1ST ISME LATIN AMERICA CONGRESS September 11 to 13, 2019. Universidad Técnica Federico Santa María, Valparaíso, Chile.

1 Local Organizing Committe

Chair Co-Chair Mónica Vásquez Michael Seeger Pontificia Universidad Católica de Chile Universidad Técnica Federico Santa María

Director Director Beatriz Cámara Cristina Dorador Universidad Técnica Federico Santa María Universidad de Antofagasta

Coordinator Coordinator Vanessa Ayala Monica Sorondo Universidad Técnica Federico Santa María Local Staff

Natalia Álvarez-Santullano Constanza Macaya Universidad Técnica Federico Santa María Universidad Técnica Federico Santa María

Bárbara Barra Leonardo Zamora Universidad Técnica Federico Santa María Universidad Técnica Federico Santa María

Roberto Durán Nicolás Zamorano Universidad Técnica Federico Santa María Universidad Técnica Federico Santa María National Scientific Committee

Beatriz Diez Verónica Molina Pontificia Universidad Católica de Chile Universidad de Playa Ancha

Eduardo Castro Nallar Julieta Orlando Universidad Andrés Bello Universidad de Chile, Chile

Martha Hengst James Robeson Universidad Católica del Norte Pontificia Universidad Católica de Valparaiso

Gloria Levicán Nicole Trefault Universidad de Santiago de Chile Universidad Mayor

Rosalba Lagos Raquel Quatrini Universidad de Chile Fundación Ciencia y Vida

2 Ximena Besoain Roberto Orellana Pontificia Universidad Católica de Chile Universidad de Playa Ancha

Rodrigo De la Iglesia Danilo Pérez Pantoja Pontificia Universidad Católica de Chile Universidad Tecnológica Metropolitana

Yoanna Eissler Francisco Remonsellez Universidad de Valparaiso Universidad Católica del Norte

Milko Jorquera Osvaldo Ulloa Universidad de la Frontera Universidad de Concepción

Miguel Martínez Universidad de Concepción International Scientific Committee

Alejandro Acosta Fernando Andreote Universidad de La Sabana, Colombia Universidad de Sao Paulo, Brasil

Cecilia Alonso Karina Antúnez Universidad de la República, Uruguay Universidad de la República, Uruguay

Luisa Falcon Filipa Godoy-Vitorino Universidad Nacional Autónoma de México, México Universidad de Puerto Rico, Puerto Rico

Leda C. Mendonça-Hagler Esperanza Martínez Universidad Federal de Rio de Janeiro, Brasil Universidad Nacional Autónoma de México, México

Luis C. Mejía Adrián Pinto Tomás INDICASAT AIP, Panamá Universidad de Costa Rica, Costa Rica

María Romina Schiaffino Diego F. Quito-Avila Consejo Nacional de Investigación Científica y Técnica Escuela Superior Politécnica del Litoral, Ecuador CONICET, Argentina Marcia María Rojas Badía Claudia Piccini Universidad de La Habana, Cuba Instituto de Investigaciones Biológicas Clemente Estable, Uruguay Luis Gabriel Wall Universidad Nacional de Quilmes, Argentina María Mercedes Zambrano Corporación CorpoGen, Colombia

César Rodríguez Universidad de Costa Rica, Costa Rica

3 Mapping 1st. ISME Latin America Congress

4 Proyección audiovisual urbana

El Taller Lowtech y Ciencia Diseño UC es una iniciativa de la Facultad de Arquitectura, Diseño y Estudios Urbanos de la Pontificia Universidad Católica de Chile, a cargo del académico e investigador Alejandro Durán, con el fin de promover el desarrollo y transferencia de proyectos con alto impacto social y una perspectiva renovada sobre la incorporación de avances tecnológicos y científicos por medio de procesos, materiales y recursos accesibles para un gran parte de la sociedad.

En este sentido, una de las líneas de investigación del taller es la divulgación y valorización científica por medios de dispositivos educativos y experiencias inmersivas.

El día 11 de septiembre, en el marco del congreso ISME-LA 2019, los estudiantes del taller realizaron una intervención digital con proyecciones en un edificio del Patio del Cañón de la Universidad Técnica Federico Santa María donde se mostraron diversas temáticas científicas plasmadas en trabajos audiovisuales.

Estudiantes: Cristóbal Alfaro, Trinidad Alliende, Eva Lea-Plaza, Francisca Brito, Andrea Diaz, Josefina Domeyko, Felipe Fuentealba, Karina Galaz, Rebeka Gallardo, María De Los Ángeles García-Huidobro, Rosario González, Teresa Millán, Jacinta San Martin, Carla Silva, Felipe Vásquez.

5 Mapping

The Lowtech and UC Design Science workshop is an initiative of the Faculty of Architecture, Design and Urban Studies of the Pontificia Universidad Católica de Chile, coordinated by the professor and researcher Alejandro Durán, in order to promote the development and transfer of projects with high social impact and a renewed perspective on the incorporation of technological and scientific advances through accessible processes, materials and resources for the society.

One of the research lines of the workshop is the dissemination and scientific valorization through educational devices and immersive experiences.

On September 11, within the framework of the ISME-LA 2019 Congress, students of the workshop carried out a digital intervention with projections in a building of the Universidad Técnica Federico Santa María where various scientific themes were shown reflected in audiovisual projections.

Students: Cristóbal Alfaro, Trinidad Alliende, Eva Lea-Plaza, Francisca Brito, Andrea Diaz, Josefina Domeyko, Felipe Fuentealba, Karina Galaz, Rebeka Gallardo, María De Los Ángeles García-Huidobro, Rosario González, Teresa Millán, Jacinta San Martin, Carla Silva, Felipe Vásquez.

6 7 Mural "Raíz de la Existencia" 1st. ISME Latin America Congress

MURAL RAÍZ DE LA EXISTENCIA Pintura mural en Cerro Larraín, frente al Parlamento chileno al otro lado de la Avenida Argentina, Valparaíso. Mural en una pared (120 m2) de un edificio de la Población Clark de 1954.

8 El objetivo de realizar un mural nace como agradecimiento a la ciudad que albergó alrededor de 400 personas durante los días del Congreso ISME-LA 2019 y refleja la idea de acercar a la comunidad de Valparaíso a los quehaceres científicos propios de esta actividad desarrollada en la Universidad Técnica Federico Santa María. También busca enaltecer el trabajo que realizan artistas y gestores culturales de organizaciones sin fines de lucro como es la ONG Valparaíso en Colores y el operador turístico Lado B Walking Tour quienes fueron los gestores de la ejecución de este mural donde el artistaJuan Pablo Gatica (Jotapé), fue capaz de plasmar su arte inspirado en la temática del congreso “Biodiversity at its best”.

Muralista: Juan Pablo Gatica, Jotapé. Nacido en Viña del Mar y vive en Valparaíso. Arquitecto con pinturas murales en Chile, Ecuador, Nicaragua, Bolivia, España y Francia. Muralista de diversos proyectos como “Valparaíso en colores” (2016-2019), Teatro Municipal Viña del Mar (2017), La Calera en colores (2018). Lema: “El hombre se hizo siempre de todo el material... con una mano blanca y otra mortal”.

9 El mural es a libre interpretación del espectador. Jotapé se inspiró en temáticas de ecología microbiana y biodiversidad para plasmar esta idea y mirada creativa y holística al mundo de los microorganismos. Se refleja la interacción entre los seres vivos que son fundamentales para la propia existencia entre el medio ambiente interno y externo, como también la imagen del ser humano surgiendo desde la cooperación. Como lo planteó Jotapé; “el Mural Raíz de la Existencia fue creado pensando en nuestro origen, la pregunta que nos hemos hecho como especie animal que en su evolución alcanzó el desarrollo de una conciencia y que hemos puesto sus facultades al servicio de buscar esa respuesta. Somos barro que originó un cuerpo vivo, un cuerpo que no ha escatimado en recursos para explicarse por qué estamos acá. Es una bella tarea entendernos, y hoy me planto con este trabajo a interpretar esa historia tan humana que traemos desde los anales remotos de nuestra existencia. Nuestros ancestros miraban las estrellas, y hoy estudiamos nuestra propia constitución y sabemos más, sin embargo, la respuesta siempre ahonda verdades cada vez más profundas e indescifrables, tal vez algún día, o tal vez nunca, contestemos la pregunta, pero qué bello es recorrer el tránsito de hallarle respuesta. Como dicen por ahí, somos una especie en viaje.”

MURAL Root of the Existence

The objective of creating a mural was born as a gift to the city that hosted around 400 persons during the days of the ISME-LA 2019 Congress held at the Universidad Técnica Federico Santa María. The mural reflects the idea of bringing the community of Valparaiso closer to the scientific world. It highlights the work of artists and cultural managers of non-profit organizations such as “Valparaiso en Colores” and the touristic operator “Lado B: Walking Tour”, who where the managers of the execution of this mural where the artist Juan Pablo Gatica (Jotapé) was able to capture his art inspired by the motto of the congress “Biodiversity at its best”.

Muralist: Juan Pablo Gatica, Jotapé. Born in Viña del Mar and lives in Valparaíso. Architect with wall paintings in Chile, Ecuador, Nicaragua, Bolivia, Spain and France. Muralist of diverse projects including “Valparaíso in colors” (2016-2019), Municipal Theater Viña del Mar (2017), La Calera in colors (2018). Motto: “The man was always made of all the material ... with a white hand and a killing hand”.

The mural is open to a free interpretation by the spectator. Jotapé was inspired by themes of microbial ecology and biodiversity, capturing this idea with a creative and holistic look to the microbial world. It reflects the interaction between living organisms that are crucial to their own existence between the internal and external environment, as well as the image of the human being emerging from the cooperation. As Jotapé says “The Mural Root of the Existence was created thinking about our origin, the question we have asked ourselves as animal species that in its evolution reached the development of a consciousness; we have put our faculties for exploring that answer. We are mud that created the living body, a body that has not spared resources to explain why we are here. It is a beautiful task to understand each other, and today with this work I try to interpret this human history, which we hold from the remote annals of our existence. Our ancestors looked at the stars, and today we study our own constitution and know more. However, the answer always delves deeper and indecipherable truths, maybe one day, or maybe never, we will answer the question, but how beautiful it is to travel searching for an answer. As some people say, we are a species on a journey”.

10 11

CONFERENCES

Bioprospection of halophilic microorganisms from the solar saltern of Manaure (Guajira, Colombia)

Bioprospección de microorganismos halófilos de las salinas de Manaure (Guajira, Colombia)

Alejandro Acosta-González2, Natalia Conde Martínez1, Edisson Tello Camacho2. (1) Doctorado en Biociencias, Facultad de Ingeniería, Universidad de la Sabana (2) Departamento de Procesos Químicos, Facultad de Ingeniería, Universidad de la Sabana

El objetivo del estudio fue la caracterización del potencial bioprospectivo de la comunidad bacteriana cultivable de las Salinas de Manaure en La Guajira, Colombia. Se implementó una estrategia de cultivos mixtos mediante la cual se seleccionó el extracto que presentó mejor actividad citotóxica y antibacteriana, para posteriormente caracterizar los aislados del cultivo mixto seleccionado. De 40 cultivos mixtos evaluados, 2 tuvieron actividad pero solo en uno de los consorcios (A1SM3-36) se pudo aislar la ceparesponsable de la actividad, identificada como Vibrio diabolicus A1SM3. A partir del fraccionamiento bioguiado del extracto del cultivo de esta cepa y su posterior análisis mediante HPLC-MS/MS y RMN, se logró identificar a la isotrisindolina como el compuesto responsable de la actividad citotóxica y antibacteriana. Posteriormente, se realizaron variaciones en la fuente de carbono, nitrógeno y de salinidad en el medio de cultivo, con el fin de establecer su efecto en la producción de este compuesto. Los datos de MS/MS obtenidos de estos cultivos fueron analizados mediante redes moleculares (molecular networking) para determinar este efecto. Adicionalmente, se logró identificar que este microorganismo también produce polihidroxibutiratos, un biopolímero comúnmente producido y acumulado por este género de bacterias, el cual es de gran interés en la industria de los plásticos. Mediante la secuenciación del genoma de Vibrio diabolicus A1SM3, se logró anotar el cluster de genes asociados a la biosíntesis de este biopolímero.La estrategía aplicada en el estudio demuestra que las estrategías clásicas de aislamiento de cepas puras es limitada para realizar estudios de bioprospección de ambientes salinos.

Universidad de la Sabana (proyectos ING139-2013 e INGPHD4-2015) y Colciencias (Beca doctoral 6172-2014)

13 Assessing the ecological role and evolutionary history of bacterial natural products biosynthesis in the genomics era

Evaluando el papel ecológico y la historia evolutiva de la biosíntesis de productos naturales bacterianos en la era (meta)genómica

Francisco Barona-Gomez1. (1) Langebio, Cinvestav-IPN

Natural products, or specialized metabolites, are important for medicine and agriculture alike, as well as for the fitness of the microorganisms that produce them. Microbial genome mining aims at extracting metabolic information from genomes of microbes presumed to produce these compounds. Typically, canonical enzyme sequences from known biosynthetic systems are identified after sequence similarity searches. Despite this being an efficient process the likelihood of identifying truly novel biosynthetic systems, referred to as chemical dark matter, is low. To overcome this limitation our group has introduced genome-mining approaches that incorporate evolutionary and ecological principles. In this talk I will present selected examples of our approaches, supported by successful cases where chemical dark matter has been unveiled, and the ecological role of the resulting natural products investigated. By defining the origins and fates of biosynthetic enzymes, as well as the biological and ecological roles of specialized metabolites, our approaches not only complement traditional genome-mining approaches as unbiased and rule- independent strategies, but they open the door to gain insights into the microbiology of specialized metabolites. In sum, our investigations provide an eco-evolutionary platform for the understanding of natural products biosynthesis in their real natural context.

14 Biotic and abiotic drivers of Mamiellophyceae picophytoplankton seasonality in north western mediterranean sea

Determinantes bióticos y abióticos en la estacionalidad del pico-plancton de la clase Mamiellophyceae en el Mediterráneo noroeste

Francois-Yves Bouget1. (1) Sorbonne Université, CNRS. Laboratory of microbial oceanography. Observatoire Oceanologique de Banyuls sur Mer, France.

In temperate regions of the ocean, phytoplankton growth is often seasonal. By conducting a 7 year metabarcoding approach in the coastal site of Banyuls Bay (North western Mediterranean sea) we unveiled significant yearly rhythms of dominant autrophs (cyanobacteria and picoeukaryotes), bacteria (sar11) and Archeae. Temperature and day length appeared to be the main drivers of seasonality (Lambert et al., ISME J, 2019). Sporadic meteorological events, in contrast had little effect of the yearly rhythms. In winter, seasonal Mamiellophyceae, including Micromonas bravo and Bathycoccus prasinos represented more than half of 18S barcodes. Together culture and microcosm studies confirmed that Mamiellophyceae strains have specific light/temperature preferenda. A bi-weekly monitoring of diversity in 3 contrasted winters revealed that co-occurences between bacteria and Mamiellophyceae varied, even though this class of microalgae are dependent on B vitamins produced by microalgae (Paerl et al., ISME J, 2018). The importance of abiotic and biotic factors in bloom regulation will be discussed in this context.

15 A chronology of multicellularity of evolution in cyanobacteria

Cronología de la evolución de la multicelularidad en cianobacterias

Tal Dagan1. (1) University of Kiel, Germany

The major transitions in evolution, such as the transition to multicellularity are characterized by cooperation between lower level entities and by division of labor. Theory suggests that division of labor drives the transition to multicellularity by eliminating the trade-off between two incompatible processes that cannot be performed simultaneously in one cell. Here we examine the evolution of the most ancient multicellular transition known today, that of cyanobacteria. We developed an approach for the precedence polarization of phenotypic traits that employs gene phylogenies and does not require a species tree. Applying our procedure to cyanobacterial genomes we reconstruct the chronology of ecological and phenotypic trait evolution in cyanobacteria. Our results show that the prime driver of multicellularity in cyanobacteria was the expansion in metabolic capacity offered by nitrogen fixation, which was accompanied by the emergence of the filamentous morphology and a reproductive life cycle. This was followed by a range of niche expansions and interactions with other species, and the progression of multicellularity into higher complexity in the form of differentiated cells and patterned multicellularity.

16 Adaptation of microbial carbon use efficiency in a warming world

Adaptación de la eficiencia del uso microbiano de carbono en un mundo en calentamiento

Kristen DeAngelis1. (1) University of Massachusetts, Amherst

Microbes are key drivers of biogeochemical cycling in terrestrial ecosystems. Terrestrial microbes and their activities regulate the amount of carbon that is stored in soils, which is more than the atmosphere and vegetation combined. Carbon use efficiency is an integrated trait that describes the portion of microbial substrate that is converted into biomass, effectively remaining in soils, with the remainder lost to the atmosphere. To understand how warming might affect this self-reinforcing feedback to the climate, we investigate a long-term field warming experiment at the Harvard Forest LTER, where soils have been heated 5 degrees Celsius above ambient temperatures for 27 years. Using field, laboratory, and modeling experiments, our research investigates how individual microbial traits, community traits and environmental factors affect carbon use efficiency and its response to temperature.

17 Microbial dynamics in space and time: the motion picture

Dinámica microbiana en el tiempo y el espacio: la película

Edward F. DeLong1. (1) Department of Oceanography, University of Hawaii at Manoa

Microbial communities regulate the cycling of energy and matter in the marine environment, yet the details of how they interact with one another, respond to environmental change, and how their activities vary in space and time, are not well understood. Genomic methods and allied technologies are now providing new perspective on the distribution of microbial taxa, genes, and processes in the marine environment. One of the larger challenges remaining is defining the dynamics and interactions of microbial taxa, gene and process distributions on appropriate spatial and temporal scales. How do microbial metabolic activities and interactions of specific planktonic microbial populations vary over the course of minutes, hours, days and weeks? Over what spatial scales? Put another way, exactly what does a typical “day in the life” of wild planktonic microbial species look like? We are leveraging Lagrangian survey strategies that employ robotic sampling techniques, and coupling these surveys with community-wide microbial gene expression analyses in wild planktonic microbial populations, to help answer some of these questions. Results using such approaches show that in surface waters, individual populations, as well as very different bacterial and archaeal species, display remarkably similar, time-variable patterns of synchronous gene expression over extended periods of time. These new results suggest that specific environmental cues may elicit cross-species coordination of gene expression among diverse microbial groups, that has potential to enable multispecies coupling of metabolic activities. We are currently trying to understand how such temporal compartmentalization of metabolism among different species might regulate matter and energy flux and biogeochemical cycles over time. The coupling of genome-enabled data with new approaches in observational oceanography has potential to advance our understanding of the inner workings of complex planktonic microbial ecosystems.

18 Bacteriophage retrospective, including some personal anecdotes

Retrospectiva de los bacteriófagos, incluyendo algunas anécdotas personales

Romilio Espejo1. (1) Biotecnología, INTA, Universidad de Chile

Los bacteriófagos recuperaron su protagonismo original en biología y medicina: En biología, al descubrirse que son los organismos mas abundantes y ubicuos, desempeñando un papel crucial en la manutención del balance microbiano en el planeta; En medicina, cuando el mayor conocimiento de sus propiedades y forma de replicación promete -y ha permitido en algunos casos- su uso exitoso como antibacterianos, en reemplazo de los antibióticos cuya efectividad es desafiada por la aparición y propagación de resistencia. Su protagonismo actual es, sin embargo, menor al que tuvieron, como objetos de estudio en los 1950s y 60s, en los descubrimientos que llevaron al advenimiento de la Biología Molecular y la comprensión de la genética: el DNA, y su mecanismo de replicación y traducción en elementos funcionales. Pero este papel tan importante fue quizás menor al que tuvieron inmediatamente después de su descubrimiento en 1915/1917 cuando fueron, como ahora, prometedores antibacterianos aplicados con relativo éxito -aun comercialmente- hasta ser reemplazados por los antibióticos descubiertos en los 1940s.

En esta presentación resumiré esta historia describiendo algunos de los hitos más importantes y algunos de los protagonistas más carismáticos que alcancé a conocer, incorporando -humildemente- algunas de mis contribuciones sobre los bacteriófagos como actores del desarrollo de la biología molecular y del balance de la microbiota y el control de infecciones bacterianas.

19 Salar´s Forests: Changing the Paradigm of Microbial Extremophiles in the Andean Altiplane

Bosques en el Salar: Cambiando el Paradigma de Microbios Extremofilos en el Altiplano

Maria Eugenia Farías1, Manuel Contreras2, Judith Klatt3, Mariana Soria1, Luis Saona1, Tatiana Stapanenko1, Daniel Kurt1, Agustina Lencina1, Patricio Villafañe1, Federico Vignale1, Pieter Visscher4. (1) Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas, PROIMI-CONICET Tucuman, Argentina (2) Centro de Ecología Aplicada (CEA) Suecia 3304, Ñuñoa, Santiago, F: 56-2-2741872 Chile (3) Microsensor Group, Max Planck Institute for Marine Microbiology, Bremen, Germany (correspondence: lgatti@ mpi-bremen.de) (4) Departments of Marine Sciences and Geoscience, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA

The central Andes represent a desert of height interspersed with abundant volcanoes, salt flats and lagoons. It is known as Puna (Argentina), Atacama (Chile) or Altiplano (Bolivia and Peru) and is characterized by extreme conditions of UV irradiation, low pressure of O2 and alkaline hypersaline waters with high abundance of S, A, Li and other compounds that are usually only found in trace concentrations. In recent decades, there has been a great increase in knowledge about the microbial communities that inhabit these environments, mainly hypersaline lagoons and salt flats. In addition, stratified communities associated with minerals such as modern stromatolites, microbial mats and gypsum endoevaporites, were reported in many of these environments increasing the interest in these ecosystems as an early earth analogue. The metagenomic, physiological and geochemical studies revealed unexpected strategies that allow these communities to thrive in salt flats by respiring As, using microbial rhodopsin systems, and diverse forms of photosynthesis, thereby serving as sinks of CO2.

In this presentation we will review these strategies and present the idea that these extremophile communities would not be restricted only to the lagoons, but that they would be extend to large areas in the salt flats, converting them into substantial CO2 sinks and O2 sources. This paradigm shift, from the perception of sterile salt flats to living salt flats would completely revolutionize their level of preservation when facing mining projects.

20 Insights into the ecology of marine aerobic anoxygenic phototrophic bacteria

Ecología de las bacterias aeróbicas anoxigénicas fototróficas marinas

Isabel Ferrera1. (1) Centro Oceanográfico de Málaga, Instituto Español de Oceanografía

The study of marine microbes has bloomed thanks to the use of molecular tools opening new windows into ecological studies. One of the major advances achieved last decade was the discovery of marine photoheterotrophic bacteria, which challenged our view on microbial food webs in the ocean. These organisms are heterotrophs that rely mainly on organic matter but are capable of harvesting light to supplement their energy requirements. In the last years, we have used various approaches to uncover the ecology of a group of marine photoheterotrophs, the aerobic anoxygenic phototrophic bacteria (AAPs). In particular, we have combined infrared microscopy, quantitative PCR and high-throughput sequencing with large sampling initiatives (i.e., the Blanes Bay Microbial Observatory, the Malaspina and Tara Oceans circumnavigation expeditions) as well as with manipulation experiments to explore their diversity, seasonality, biogeography and, more importantly, their functional role in marine ecosystems. Our results confirm that the AAPs are widely distributed in the global surface oceans and present a clear seasonality, containing ecotypes showing distinctive niche partitioning, rather than being a cohesive functional group. But foremost, we have found that the AAPs are fast-growing bacteria contributing significantly to the recycling of organic matter and that they can be stimulated by light in the marine environment.

21 Cutaneous microbiota and antimicrobial peptides may explain the coexistence of two Andean frog species with the lethal pathogen Batrachochytrium dendrobatidis

Microbiota cutánea y péptidos antimicrobianos ayudan a explicar la coexistencia de dos especies de ranas andinas con el patógeno Batrachochytrium dendrobatidis

Sandra Victoria Flechas1, Alejandro Acosta-González2, Laura A. Escobar3, Jordan Kueneman4,8, Zilpa Adriana Sánchez-Quitian3,5, Claudia M. Parra-Giraldo3, Louise Rollins-Smith6, Laura K. Reinert6, Vance T. Vredenburg7, Adolfo Amézquita1, Douglas C. Woodhams4,8. (1) Department of Biological Sciences, Universidad de los Andes, Bogotá, 111711, Colombia (2) Faculty of Engineering, Universidad de la Sabana, Chía, AA 53753, Colombia (3) Department of Microbiology, Faculty of Sciences, Pontificia Universidad Javeriana, Bogotá, AA 56710, Colombia (4) Biology Department, University of Massachusetts Boston, Boston, MA 02125, USA (5) Environmental Management Group. Department of Biology and Microbiology, Universidad de Boyacá, Tunja, 150000003, Colombia (6) Department of Pathology, Microbiology and Immunology, Vanderbilt University, School of Medicine, Nashville, TN 37232, USA (7) Department of Biology, San Francisco State University, San Francisco, CA 94132-1722, USA (8) Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Republic of Panama

The pathogenic fungus Batrachochytrium dendrobatidis (Bd) has caused dramatic declines in the populations of many amphibian species around the world. However, other species have survived these epizootic events. Several studies suggest that the bacteria present in the frog’s skin play an important role in the defense against the pathogen allowing the frogs to survive the lethal effects of Bd. To understand the role of the cutaneous microbiota as a component of the resistance to the infection, we studied two species of sympatric frogs that inhabit the Colombian Andes, Dendropsophus labialis (Hylidae) and Rheobates palmatus (Aromobatidae), which have coexisted with the pathogenic fungus for at least a decade without evidence of population decline. Previous studies showed that the prevalence of infection is high in both species, despite infection levels have remaining low. Here we evaluate both, the composition of the microbial community (cultivable and non-culturable) and the presence of antimicrobial peptides in the three stages of development (tadpole, juvenile, adult) of both species of frogs, in order to determine their ability to inhibit the pathogen and to understand the role of peptides in the structuring of the skin bacterial communities. Our results suggest that the composition of the bacterial community and the antimicrobial peptides secreted in the skin are specific at each stage of development. Additionally, a high proportion of isolated bacterial species, belonging mainly to the phylum Proteobacteria and Firmicutes, were characterized as anti-Bd. The antimicrobial peptides significantly inhibited the growth of Bd, but did not affect bacterial growth, even in some cases antimicrobia; peptides promoted the growth of the cutaneous microbiota. Our study suggests that symbiotic bacteria and antimicrobial peptides together contribute to the ability of Andean amphibian species to coexist with the global pandemic Bd lineage.

22 Ecology of supraglacial microbial habitats

Ecología de hábitats microbianos supraglaciales

Andrea Franzetti1, Francesca Pittino1, Roberto Sergio Azzoni2, Guglielmina Diolaiuti2, Roberto Ambrosini2, Veronica Molina3, Michael Seeger4. (1) Università degli Studi di Milano-Bicocca, Dipartimento di Scienze dell?Ambiente e della Terra. Piazza della Scienza 1, 20126 Milano. (2) Università degli Studi di Milano, Dipartimento di Scienze e Politiche Ambientali. Via Celoria 2, 20133 Milano. (3) Universidad de Playa Ancha, Facultad de Ciencias Naturales y Exactas. Avenida Leopoldo Carvallo 270, Playa Ancha (4) Universidad Técnica Federico Santa María, Department of Chemistry. Avenida España 1680, Valparaíso

Cryoconite holes are small ponds full of melting water with a sediment on the bottom present on the surface of glaciers. Although they are characterized by extreme conditions such as low temperature and high solar irradiance, they host highly biodiverse bacterial communities. In our studies of the last 7 years, we investigated the diversity of bacterial communities in cryoconite on Italian Alps and other mountain ranges (Andes, Karakoram) and contribute to the understanding of the ecological processes shaping their community structures. Although cryoconite bacterial communities share a similar core microbiome worldwide, dominated by Cyanobacteria, Actinobacteria, Proteobacteria and Bacteroidetes, their community structure strongly differ among the glaciers. Local conditions such as mineral composition of the debris and climatic condition might explain these differences. Cryoconite communities also differ from those present in moraine sediments, which act as sources of bacteria for these environments, and show a temporal trend along the ablation season. This temporal shift follows a typical ecological succession of newly colonized environments with autotrophs, decreasing and heterotrophs increasing during the melting season. Interestingly, this pattern could not be explained by an ecological succession occurring within each hole, due to their short life on mountain glaciers. These and other evidences suggested that the apparently simple communities of these environments are structured by a diverse range of ecological processes, that include local transport by wind, species-sorting effects, ecological succession and bacterial dispersion.

Shot-gun metagenomics and metatanscriptomics also revealed that supraglacial bacterial communities exhibit a high functional biodiversity as they can exploit organic carbon both as energy and carbon source. The high solar radiation at glacier surface favours both oxygenic and anoxygenic photosynthesis, likely by organisms with both pure autotrophic and mixotrophic lifestyles. Light might also support photochemical carbon monoxide production and its microbiologically mediated consumption. These metabolic functions are not all concomitantly expressed, but show a temporal pattern of expression along a typical day of the melting season on an Alpine glacier. Aerobic respiration, oxygenic photosynthesis and anoxygenic photosynthesis were expressed at maximum levels at different times of the day, thus suggesting the presence of temporal ecological niches that may contribute to the whole taxonomic and functional biodiversity.

23 Is it really simple? Exploring the relationship between the cervicovaginal microbiota and Human Papilloma Virus infections

¿Es realmente simple? Explorando la relación entre la microbiota cervicovaginal y las infecciones por el virus del papiloma humano

Filipa Godoy-Vitorino1, Josefina Romaguera2. (1) Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico (2) Ob/Gyn, School of Medicine, University of Puerto Rico

Cervical cancer (CC) is the fourth most common female cancer worldwide and the second most common cancer in developing countries. While persistent infection with high-risk HPV (hr-HPV) types is necessary, it is not a sufficient cause of cervical cancer and microbiome-related pathways may be involved. With the advent of the human microbiome discoveries – we now know that microbes play a role in the susceptibility to HPV and neoplasia. In fact, emerging evidence indicates that cervicovaginal microbiota plays a substantial role in the acquisition and persistence of HPV infection and subsequent development of cervical cancer. Our team has examined the association between cervical bacteria and fungi with HPV varying degrees of cervical intraepithelial neoplasia (CIN) in a sample of women infected with hr- and low-risk (LR) HPV attending two gynecology clinics in San Juan, Puerto Rico. We found that HPV diversity did not change with cervical dysplasia and cervical bacteria were more diverse in patients with CIN3 pre-cancerous lesions. In addition, we found a dysbiotic (altered homeostatic) community enriched in Atopobium vaginae and Gardnerella vaginalis in patients with CIN3 lesions. No significant association was found between bacterial biomarkers and HPV infections. However, fungal diversity was significantly higher in cervical samples with hr-HPV and in samples with Atypical Squamous Cells of Undetermined Significance (ASCUS). This is an important first step towards exploring the real picture at the cervical epithelial frontier, to appreciate microbiome-related changes conducive to cervical cancer.

24 Core Body Temperature and Thermoregulation in Space: Lessons learned from studies on ground and on the International Space Station (ISS)

Temperatura corporal y termoregulación en el espacio: Lecciones aprendidas de estudios en la Tierra y en la Estación Espacial Internacional (EEI)

Hanns-Christian Gunga1. (1) Charité University Medicine Berlin Institute of Physiology - Center for Space Medicine Berlin Charitéplatz 1, 10117 Berlin, Germany

Keywords: Heat stress, extravehicular activity, Double sensor, circadian rhythm

The hypothalamus controls and regulates thermoregulation to maintain a core body temperature of around 37 °C. On ground the body temperature fluctuates by only +/- 0.5°C throughout the day (circadian rhythm). In space the heat loss pathways are challenged due to the lack of natural convection which results in the diminished occurrence and/ or efficiency of evaporation. Three investigations will be presented. All of these dealt with core body temperature and circadian rhythm changes under terrestrial and micro-g conditions, i.e. i) bed rest, ii) during long-term isolation and confinement, and iii) in space. In the first study (study 1), a new methodology was tested in comparison to rectal temperatures in 7 male subjects during a long-term bed rest. In study 2, body core temperatures were measured in 6 male subjects who participated in MARS500. Finally, 11 astronauts were monitored before flight, several times in space on the ISS, and after spaceflight (study 3). Study 1 revealed that the device correlated well (r>0.704) with the rectal temperature recordings. Study 2 showed that the subjects lost their circadian core temperature profiles during Mars500 and study 3 showed marked and prolonged increases during exercise in space. Changes in body temperature and its circadian undulation can be markedly attenuated in space. Further studies on this topic are urgently needed because i) the frequency, length, and intensity of extravehicular activities will increase in future and ii) any alteration of the circadian rhythms might aggravate the physical, psychological, and cognitive performance of humans in space.

25 To spore or not to spore: bacterial survival revisited

Esporular o no esporular: re-explorando la supervivencia bacteriana

Pilar Junier1. (1) Laboratory of Microbiology, University of Neuchatel

Microorganisms have evolved various strategies to withstand environmental conditions that limit active growth. To endure the harsh stress and resume growth once the stress subsides some microorganisms can adopt a viable but non-growing or dormant state. Dormancy often involves the formation of a specialized cell, also known as spore or spore-like cell. The study of a group of tractable models has provided the foundation for understanding the genetic bases of spore development, and subsequently allowed the biochemical characterization of the underlying mechanism. However, studies of spore-formation are not only important for understanding mechanisms of cellular differentiation and their regulation in response to environmental cues, but also to provide insight into when and how the breakpoint between monoderm (classically called Gram-positive) bacteria and diderm (Gram-negative) bacteria occurred in evolution. Up to now, spores have been described exclusively in a small number of bacterial clades. However, given the diversity of microbial ecosystems, there is a significant chance that other pathways based on different genes and generating uncharacterized spore-like cells remain to be discovered. The development of a suite of methods to investigate sporulation in environmental samples suggest that spore-like cells are distributed in other clades as yet not known to produce such dormant structures. This is supported by a culture-based approach and by the characterization of novel sporulating clades. Our findings challenge the current knowledge of sporulation and the evolution of this trait. Furthermore, our planet is expected to undergo increasing episodes of environmental stress. Given the primordial role of bacteria in ecosystem functioning, studying microbial dormancy as a model of a natural response to changing environmental conditions could constitute a stepping-stone to improve our ability to predict the response of the biosphere to climate change.

26 Microbes in subsurface undergoing treated wastewater infiltration

Microbios en el subsuelo sometidos a infiltración de aguas residuales tratadas

AH Kaksonen1, GJ Puzon1, J Wylie1, M Morgan2, T Walsh2, K Barry3, MJ Donn1, E Bekele1, J Vanderzalm3. (1) CSIRO Land and Water, Private Bag No.5, Wembley, Western Australia 6913, Australia (2) CSIRO Land and Water, Black Mountain Laboratories, P.O. Box 1700, Canberra, Australian Capital Territory 2601, Australia (3) CSIRO Land and Water, Private Bag 2, Glen Osmond, South Australia 5064, Australia

Urbanisation and climate variability have resulted in increasing pressure on water resources and growing interest to harvest and use alternative water sources, such as treated wastewater. Aquifers can be used to improve water quality through microbial and physicochemical processes, and store water via managed aquifer recharge (MAR) to balance supply with demand for providing an alternative water source.

This study evaluated microbial communities in soil column infiltration experiments and field-scale MAR schemes which used Floreat infiltration gallery and Alice Springs open soil aquifer treatment basins. Microbial cells numbers in soil increased as a result of infiltration of treated wastewater in both column and infiltration gallery experiment. The cell numbers were considerably higher in the top clogging layer sampled from the Alice Spring field site as compared to the column and infiltration gallery studies. The results indicate that increased microbial biomass may contribute to the clogging of the aquifer.

The column and Floreat MAR studies showed clear differences in the bacterial and eukaryotic communities before and after infiltration. The bacterial families detected by pyrosequencing included both aerobes and anaerobes, and chemoorganotrophs, chemolithotrophs and phototrophs. Members of some families are common in human and animal digestive tracts and some contain pathogenic species. The dominant archaeal groups detected were methanogens and ammonia-oxidisers. Examples of eukaryotic microbes detected include fungi, protists, algae and plasmodial slime molds. This diverse microbiome can contribute to the biogeochemical cycling of various elements such as carbon, nutrients and metals.

Keywords: Archaea, Bacteria, Bioclogging, Biogeochemistry, Eukaryotes, Infiltration, Managed aquifer recharge, Microbial community, Treated wastewater

Acknowledgements: The work was supported by Australian Water Recycling Centre of Excellence, CSIRO Land and Water, Power Water Corporation, Water Corporation of Western Australia, City West Water and Barwon Water.

27 Organelle genomes of oceanic picophytoplankters (Chloropicophyceae) reveal convergent gene losses and a variant plastid genetic code

Genomas extranucleares del picofitoplancton oceánico (Chloropicophyceae) revela una perdida convergente de genes y una variante del código genético plastidial

Adriana Lopes Dos Santos1. (1) Nanyang Technological University, Singapore

Picoplanktonic green algae belonging to the class Chloropicophyceae, previously called prasinophytes clade VII, play a key role in marine phytoplankton communities. Analysis of sequences from the variable V9 region of the 18S rRNA gene collected during the Tara Oceans expedition and in the frame of the Ocean Sampling Day consortium revealed that these picoplanktonic algae are important components of marine phytoplankton communities, particularly in moderately oligotrophic waters. The newly erected class of Chloropicophyceae comprises two genera (Chloropicon and Chloroparvula) containing each several species that can only be distinguished by molecular data. We sequenced the plastomes and mitogenomes of several Chloropicophyceae species to better delineate the phylogenetic affinities of these taxa and to infer the suite of changes that their organelle genomes sustained during evolution. Although the plastome sustained considerable changes in gene content and order at the time the two genera split, subsequently it remained stable and maintained a very small size. Both organelle genomes lost a common set of three tRNA genes. This loss was accompanied by important variations in codon usage. By comparing the sequences of plastid protein- coding genes from chloropicophycean and other greeen algae with those of the corresponding predicted proteins, we discovered that the AUA codon was reassigned from isoleucine to methionine in Chloroparvula. This non-canonical genetic code has not been reported previously in plastids.

28 Diversity, temporal dynamics, and anti-pathogen activity of endophytic fungi in Coffea arabica in Panama

Diversidad, dinámica temporal, y actividad anti-patógeno de hongos endófitos en Coffee arabica en Panamá

Luis C. Mejía2,1, Luis Ramírez-Camejo2,1, Jorge S. Vinda2, Cristopher A. Boya1, Evangelina López-Vdovenko2,1, Ariel Raschella1, Kyria Ávila1, Marjorie Cedeño1, Marta Vargas2, Marcelino Gutiérrez1, Edward Allen Herre2, Kristin Saltonstall2. (1) Centro de Biodiversidad y Descubrimiento de Drogas, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT-AIP), Panamá (2) Smithsonian Tropical Research Institute, Panamá Email:[email protected]

Endophytic fungal communities include species that provide benefits, such as tolerance to pathogens and pests, to their host plants. Understanding how these communities assemble and their temporal dynamics, is key for developing strategies using applications of these fungi as protectors of plant crops. We used next generation sequencing (NGS) of amplicons of the ITS1 region to identify the endophytic fungal communities of leaves, and roots of three coffee (Coffea arabica) varieties i.e. Geisha, Catuai, and Typica. We compared these fungal communities with those in soil associated with the sampled roots to generate information on the temporal dynamics of these communities and possible factors that influence them. We found a high diversity of endophytic fungi associated with C. arabica in Panama, with > 8,000 fungal OTUs. Community composition was more influenced by plant organ and source locality than coffee variety. The relative abundance of fungal taxa also varied over the six months sampling period (one sample per month, per substrate, for each of 45 sampled trees) and we isolated fungi that inhibit the growth of coffee pathogens, in vitro. Further, we evaluated the endophytic fungi with inhibitory activity to control these pathogens, through the adaptation of MALDI imaging mass spectrometry in leaves of coffee plants co-inoculated with a pathogen and an endophytic fungus. Results show that the endophyte produce defensive metabolites only in presence of the pathogens. We will discuss these results in the context of their relevance for the development of endophytic fungi as plant protectors.

Key words: Coffee, endophytic fungi, community assembly, temporal dynamics, biological control,Hemileia vastatrix, Mycena citricolor, NGS, metagenomics, microbiome.

29 Biodiversity of yeasts associated with neotropical ecosystems

Biodiversidad de levaduras asociadas con ecosistemas neotropicales

Leda Mendonca-Hagler1, José Roberto Ribeiro1, Anderson S. Cabral1, Allen N. Hagler1. (1) Federal University of Rio de Janeiro, Brazil

Tropical biomes are rich in biodiversity with high levels of endemism, and often they harbor threatened ecosystems. Fungi, including yeasts, are good models to study Microbial Ecology. Brazil has diverse biomes, including areas with pristine forests. Results from about one hundred yeast ecology studies, including coastal ecosystems, rain forests, and agro-ecosystems, will be presented. Yeasts were isolated using traditional culture media, and additional differential and enrichment media. Hundreds of yeast cultures were deposited in Culture Collections, some representing new species. Yeast cultures were identified by conventional taxonomy, often complemented by phylogenetic criteria. Cultivation-independent methods were used in few studies. Yeast diversity studies showed distinct yeast communities associated with different habitats. Most studies detected the prevalent yeast species of communities, but detection of rare species, present in more stable environments, is incomplete and represent most of their diversty. In ephemeral habitats, temporal changes on communities were detected. The yeast communities showed the following trends: plant surfaces were covered by basidiomycetous yeasts and Aureobasidium spp. Green fruits have similar species as plant surfaces, changing during the ripening process to include ascomycetous species, vectored by insects. Rotting cacti showed specific associations with insects and characteristic yeast communities, comparable to cacti from other regions. Drosophilids of the tropical forests have similar yeast groups to those found in temperate forests, with higher proportion ofKloeckera spp., Hanseniaspora spp and Issachenkia spp and less Kluyveromyces spp. and Saccharomyces spp. Flower nectars are visited by insects transporting ascomycetous yeasts, ex.Metschinikovia spp. The role of yeasts in multiple environmental interactions will be discussed.

30 The route from soil microbial isolates to plant protection bioproducts

La ruta desde aislados microbianos de suelo hasta la obtención de bioproductos para la protección de plantas

Rolando Morán1, Idania Wong1, Danalay Somonte1, Laritza Domínguez 1, Aylin Nordelo1, Yanara Victoria1, Liszoe Galdós1, Ileana Sánchez1, Ramón Franco1, Irene Alvarez1, Yunier Paneque1, Nemecio González1, Jesús Zamora2, Eulogio Pimentel 3. (1) Investigación y Desarrollo, Centro de Ingeniería Genética y Biotecnología (CIGB) de Camagüey (2) Dirección de Producción, Centro de Ingeniería Genética y Biotecnología (3) Dirección General, Centro de Ingeniería Genética y Biotecnología

The rhizosphere microbiome plays an important role in plant growth, nutrition and health. Plants invest a significant proportion of their photosynthetically-fixed carbon sources in the maintenance of rhizosphere microbiota. In return, beneficial microbes provide important services to the plant improving root architecture, enhancing nutrient uptake, and offering protection against pathogens. Considering the rhizosphere a valuable source of useful microorganisms, the present work describes the strategy developed for isolation and evaluation of soil bacteria to elaborate agricultural bioproducts. Successful results obtained with the long-term application of the bacterial-based product called HeberNem® on plant parasitic nematode control, are discussed. Some other examples of microbial isolates with plant pest and disease control properties are shown. The study of their mechanism of action has embraced not only the direct pesticide activity against pathogens but also the role of plant-microbe interactions asaway to improve the plant protection. Apart from the metabolites acknowledged as responsible for pest control, some microbial compounds involved in plant growth promoting effects were identified. The ability of root protective biofilm formation exhibited by some of the selected microorganisms was detected. In addition, the induction of plant defense response, either local and systemic, by the application to root plant area of some of the bacterial isolates has been established, through measuring differential plant gene expression. Soluble and volatile compounds derived from microbial isolates with putative beneficial attributes are being identified combining chromatographic and mass spectrometry methods. Technological developments have been performed to optimize the appropriate formulations for agricultural application.

31 Insights into biotic and abiotic modulation of ocean´s mesopelagic plankton community

Perspectivas de la modulación biótica y abiótica de la comunidad planctónica mesopelágica en el oceano

Alejandro Andrés Murillo1, Rigonato Janaina2, Budinich Marko3, Brandão Manoela 4, Pierella Juan5, Soviadan Dodji6, Gregory Ann7, Coordinators The Tara Oceans 8, Karsenti Erik5, Bork Peer9, Lombard Fabien4, De Vargas Colomban3, Sunagawa Shinichi 10, Gehlen Marion11, Sullivan Matthew B.7, Iudicone Daniele12, Bowler Chris5, Eveillard Damien13, Stemmann Lars4, Wincker Patrick2, Jaillon Olivier2. (1) Structural and computational biology, None, European Molecular Biology Laboratory (EMBL) (2) Génomique Métabolique, Genoscope, Institut de biologie François Jacob, Commissariat à l´Energie Atomique (CEA), CNRS, Université Evry, Université Paris-Saclay (3) Sorbonne Université, CNRS, Station Biologique de Roscoff (4) Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire d´oceanographie de Villefranche (LOV), Observatoire Océanologique (5) Institut de Biologie de l´ENS (IBENS), Département de biologie, École normale supérieure, CNRS, INSERM, Université PSL (6) Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire d?oceanographie de Villefranche (LOV), Observatoire Océanologique (7) Department of Microbiology, The Ohio State University, Columbus (8) http://oceans.taraexpeditions.org (9) Structural and Computational Biology, European Molecular Biology Laboratory (10) Department of Biology; Institute of Microbiology and Swiss Institute of Bioinformatics, ETH Zurich (11) Institut Pierre Simon Laplace, Laboratoire des Sciences du Climat et de l?Environnement, Université Paris- Saclay (12) Stazione Zoologica Anton Dohrn, Naples (13) Université de Nantes, Centrale Nantes, CNRS, LS2N

In the global ocean, sunlight declines exponentially through the water column, until light-driven processes cease and alternative metabolisms take over. In this ocean layer, the mesopelagic zone (200 to 1000 m depth), a puzzling planktonic community dwell. This ecosystem has been studied for more than 20 years, but it’s still under-sampled and –studied, compared to the surface layers of the ocean (Epipelagic layer, 0 to 200 m depth), despite it represents twenty percent of the ocean volume and plays a key role in the global biogeochemical cycles. Here we use genomics and imaging approaches to characterize the diversity and structuration processes of mesopelagic plankton, across 135 samples covering 32 globally-distributed tropical/subtropical sites, including 14 samples covering 3 oxygen minimum zones (OMZs). We explore data from viral and Prokaryotic metagenomes, pico- and nano-meso eukaryotes metabarcoding and mesozooplankton imaging, to analyze in an integrated way the interactions of the plankton assemblage. Across all Domains, communities are differently composed in mesopelagic than in epipelagic waters. Most mesopelagic endemic taxa are affiliated with Proteobacteria for Prokaryotes and Diplonemida for eukaryotes. OMZ site communities are characterized by a distinctive signature of viruses and Prokaryotes, but not for Eukaryotes, suggesting different adaptation strategies to anoxic conditions. The processes structuring communities seemsto be dominated at large scale by water masses connectivity and at microscale by biotic interactions. These influences result from both autochthonous plankton as well as via sinking particles. This multidisciplinary large-scale survey provides a foundation of knowledge on the mesopelagic ecosystem at large.

This study is part of the “Ocean Plankton, Climate and Development” project funded by the French Facility for Global Environment (FFEM).

32 Riddles from the Arctic Ocean

Enigmas del Océano Ártico

Carlos Pedrós-Alió1. (1) Systems Biology Program, Centro Nacional de Biotecnología, CSIC, Madrid, Spain

Overwintering cruises carried out from 2003 to 2008 provided information about the seasonal patterns of microbial plankton including the polar night. One surprise was that phytoplankton started to grow exponentially already in the middle of February, despite a 1.7 m thick layer of ice with snow on top and the very few light hours. This growth prepared the way for the well-characterized late spring bloom that is one of the main features of polar oceans. Superimposed on this increase of algae with longer days, there are many intriguing phenomena that we have been studying for years. We will examine three examples: the metabolism of archaea during their winter bloom, the expression of the proteorhodopsin gene along the seasons, and the iron wars among different bacteria during the spring. All of these were totally unexpected events that could be analyzed only because seasonal sampling was possible.

33 The Host-Microbe Symbioses Research Group at the University of Costa Rica

Quehacer Científico del Grupo de Investigación en Simbiosis Hospedero-Microorganismo de la Universidad de Costa Rica

Adrián A. Pinto Tomás1. (1) Departamento de Bioquímica, Escuela de Medicina; Centro de Investigación en Estructuras Microscópicas y Centro de Investigación en Biología Celular y Molecular, Universidad de Costa Rica

Costa Rica is considered a biodiversity hotspot due to its wide variety of ecosystems located within a relatively small area. It is ideal for microbial ecology research because of its network of National Parks and Research Stations, which are distributed along strategically designed Conservation Areas protecting biological corridors that allow genetic exchange between wild populations. Our group studies symbiotic interactions where microbes provide essential services to their hosts that could translate into discoveries in the fields of medicine, bioenergy, and agriculture. Our main research model are leaf-cutting ants, where we showed that potentially symbiotic microbes are transferred vertically by founding queens within the inoculum of their fungus garden. Some of these symbionts are well-known antibiotic-producers that help the ants keep their colony healthy. This emerging principle of defensive symbioses alongside actinomycetes seems to be occurring in most of the insects that we have studied, including conspicuous tropical species such as Bullet Ants and Meliponid stingless bees, and has already produced leads for new antibiotics. We also tested this principle in amphibians, where we identified skin bacteria capable of inhibiting the pathogenic Batrachochytrium dendrobatidis strain that circulates in the country, and we have joined international initiatives aiming to test these principles in humans. Our efforts in these joint initiatives are centered in unique Costa Rican populations such as the so-called Blue Zone in the Nicoya Peninsula, an area with an unusually high numberof centenarians. Taken together, these examples showcase the potential of our region for international collaboration in microbial ecology.

34 Natural products involved in interspecies interactions of microbial symbionts in Brazil

Productos naturales involucrados en interacciones enrespecies de simbiontes microbianos en Brazil

Mônica T. Pupo1. (1) Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of Sao Paulo

Small molecules produced by microbial symbionts might play important roles in the fitness of different hosts. Our research group is interested in deciphering the functions of natural products produced by microbial symbionts of insects and amphibians, and also to look for possible pharmacological applications for these signaling molecules. For this, we have sampled different species of Attine ants, stingless bees and frogs in distinct Brazilian biomes. In this presentation I will discuss some examples of pyrazines isolated from bacterial symbionts that are chemical signals for their ant and frog hosts. I will also show antimicrobial polyketides and non-ribosomal peptides involved in protective bacterial symbiosis of stingless bees. Finally, understanding the roles of small molecules in their ecological niche can lead to the discovery of pharmacologically useful compounds. This is exemplified by a structurally complex polyketide isolated from a bacterial symbiont of ants that has promising in vivo antifungal activity.

35 Expanding and exploring the catalogued diversity of Acidithiobacillia class acidophiles from novel niches

Ampliando la diversidad catalogada de acidófilos de la clase Acidithiobacillia a partir de la exploración de nuevos nichos

Raquel Quatrini1,2. (1) Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile. (2) Microbial Ecophysiology Laboratory, Fundación Ciencia & Vida, Santiago, Chile.

Extreme acidophiles are responsible for accelerating the oxidative dissolution of sulfide minerals, playing central roles in the geochemical cycling of diverse elements in low pH environments. Acidithiobacillus species are frequent and numerically relevant members of most analysed microbiomes inhabiting such econiches. Being capable of biogenic acid production and oxidation of reduced sulfur compounds, three species of the genus, A. ferrooxidans, A. thiooxidans and A. caldus, have been exploited industrially in the recovery of valuable metals and other relevant elements from ores and wastes. Despite these shared abilities, phenotypic variability of strains collected worldwide for over a century has pinpointed the acidithiobacilli as a heterogeneous group requiring taxonomical revision. The genetic basis of this heterogeneity remains poorly explored.

In this work, we expand the catalogued diversity of the taxon by sampling and sequencing Acidithiobacillus representatives from novel niches. Combining molecular systematics approaches, with pangenomics and comparative genomic analyses, we provide support for the reclassification of novel and cryptic strains into new genera, species and subspecies. To achieve a better understanding of the genome-level changes that drive ecological adaptation and lineage differentiation, intra- and inter-lineage diversity has been assessed and linage-specific gene pools identified. Distribution and phylogeny of relevant lifestyle-determining traits are analysed herein to provide clues on the factors and mechanisms driving adaptation and divergence of these model acidophiles.

Acknowledgements: Fondecyt 1181251 (RQ); Basal AFB170004 (RQ); Millennium Science Initiative, Ministry of Economy, Development and Tourism of Chile under Grant “Millennium Nucleus in the Biology of the Intestinal Microbiota”.

36 Multi-omics of the hyperarid Namib Desert

Multiomicas del desierto hiper árido de Namibia

Jean-Baptiste Ramond1. (1) Pontificia Universidad Católica de Chile

Deserts cover around a fifth of the Earth´s terrestrial surface and represent over a third of the planet’s biomes. It is also predicted that these dominant ecosystems will continue to expand globally with climate change. In these poly- extreme environments, where the presence of plants and animals is limited, microbial communities dominate and drive most of nutrient biogeochemical cycling.

The Namib Desert of south western Africa is one of the oldest deserts in the world (being at least 43 million years old) and has been hyperarid in its central part for the last 5 million years in its central part. Hence, we used it as a model ecosystem to understand the long term adaptation of environmental microbial communities to deserts’ harsh conditions. To achieve this, we have employed a suite of meta-omics tools (-genomics, -transcriptomics and -proteomics) to capture the microbial diversity and evaluate their function in multiple biotopes. This holistic approach has enabled us to challenge long-lasting desert microbial ecology paradigms.

37 Bacillus from different ecosystems: potentialities for agrobiotechnological applications

Bacillus aislado de diferentes ecosistemas: potencialidades para aplicaciones agrobiotecnológicas

Marcia María Rojas1, Daymara Sánchez Castro1, Yoania Ríos Rocafull2, Janet Rodríguez Sánchez2, Michael Seeger Pfeifer3, Moore Edward R. B.4. (1) Grupo de Ecología Microbiana, Departamento de Microbiología y Virología, Facultad de Biología, Universidad de La Habana. La Habana. Cuba. [email protected] (2) Dpto. de Recursos Genéticos Microbianos, Instituto de Investigaciones Fundamentales en Agricultura Tropical “Alejandro de Humboldt”, (INIFAT), La Habana, Cuba (3) Universidad Técnica Federico Santa María, Valparaíso, Chile (4) CCUG, University of Gothenburg, Gothenburg, Suecia ABSTRACT

To ensure the increase of food production and the sustainable use of soil, the interaction and diversity of the plant growth promoting bacteria to promote the growth of plants and the biological control of pathogens and in particular the Bacillus genus can be exploited. The objective of this work was to characterize strains of the Bacilli class form different crops with potential in the promotion of plant growth and antagonistic activity against fungal pathogens. Isolation of aerobic Gram positive endospore forming bacteria associated with maize, rice and coffee plants were carried out in different growing areas. The potentialities of the strains were determined, as well as antagonism against fungal pathogens and the production of different metabolite those support it. The mobility and biofilm formation were tested as colonizing advantage for the plant-bacteria interaction. Several evaluated strains showed the ability to solubilize three sources of inorganic phosphates, produce ammonia, indoles and the enzymes ACC deaminase and phosphatases and exert an antagonistic effect based on lytic enzymes, biosurfactants and HCN production. The biological feasibility of the application of selected strains in riceand tomato under in vitro and in vivo conditions, respectively, were demonstrated. The selected strains were identified by sequencing the 16S Bacillusas , which offers good potentialities in the agrobiological application of these bacteria for the sustainable agriculture.

38 Gases and the Gut Microbiome

Gases y el microbioma intestinal

Thomas Schmidt1. (1) Departments of Internal Medicine and Ecology & Evolutionary Biology, University of Michigan, United States

Metabolites produced by microbes in the gut are essential to human health. The composition of microbial metabolites is determined largely by diet, especially the complex polysaccharides that are not digested by the host and fuel the metabolism of microbes in the large intestine – the gut microbiome. Surprisingly, dissolved gasses in the large intestine also impact the composition and metabolism of the gut microbiome. In a remarkable example of niche construction, we found that colonic epithelial cells govern the oxygen concentration in the colon through respiration, which is controlled by microbial fermentation products. Increasing the fermentation products decreases the oxygen concentration which, in turn, selects for bacteria with high-affinity cytochrome oxidases – an ideal enzyme for low- oxygen environments. Another important gas in the gut environment is hydrogen. This common product of bacterial fermentation accumulates to supersaturated concentrations and shifts the profile of fermentation products in several prevalent bacteria. Hydrogen is consumed by methanogenic archaea and acetogenic bacteria creating a dynamic regulatory process. Finally, carbon dioxide is required by most members of the gut microbiome. Even though the host buffers the environment with bicarbonate, the metabolism of some microbes suggests that concentrations of carbon dioxide are limiting. Using a combination of synthetic microbial communities, gnotobiotic mice and healthy human cohorts, we are testing a model for the controls and consequences of the composition of dissolved gases in shaping the composition and metabolism of the gut microbiome.

39 Tracking viruses in nature: Patterns, processes and paradigms throughout the global oceans

Rastreando virus en la naturaleza: patrones, procesos y paradigmas en el océano global

Matthew Sullivan1. (1) Department of Microbiology, The Ohio State University, United States

Microbes are recently recognized as driving the energy and nutrient transformations that fuel Earth’s ecosystems in soils, oceans and humans. Where studied, viruses appear to modulate these microbial impacts in ways ranging from mortality and nutrient recycling to extensive metabolic reprogramming during infection. As environmental virology strives to get a handle on the global virosphere (the diversity of viruses in nature), we face challenges to organize this ‘sequence space’ (create a sequence-based viral taxonomy), link these viruses to their natural hosts (who infects whom), and establish how virus populations are structured (ecological drivers) and impact natural ecosystems (their impacts). Here I will share current thinking on how to study viruses in complex communities and how these efforts are revealing new biology with particular focus on the patterns, processes and paradigms emergent from studying the Tara Oceans global datasets. These advances in viral ecogenomics provide fundamental information critical for bringing viruses into ecosystem models, and the new capabilities are empowering a new generation of eco-systems biologists.

40 Microbiome and biochemical profiles changes in no-till agriculture soil. Effects of intensification of crop rotation and tillage

Cambios del microbioma y de los perfiles bioquímicos del suelo por efectos de la intensificación de la rotación de cultivos en agricultura en siembra directa

Luis G. Wall1. (1) Department of Science and Technology, University of Quilmes, Argentina

In Argentina more than 22 million Ha are no-till cultivated lands. Working with actual productive fields, we have analysed different farmers’ assays aiming to look for the effects of intensification and diversification of crop rotation (5 different levels of intensification of crop rotation), or tillage effects (changing from till to no -till and vice versa), on soil health properties. Enzymatic profiles, whole soil lipids fatty acid profiles, 16s DNA bar coding sequencing, meso- and macro-fauna abundance of different taxonomic groups, and proportion of soil micro-aggregates were analysed. After three years of treatments all biological and biochemical data were able to discriminate between soil treatments. Most biological activities, at different level of complexity, show good correlation with intensification of crop rotation. It was possible to find responders OTUs to the different agricultural managements. The analyses at the water resistant microaggregate level open new scenario for searching of responders and new biological indexes. With all this data we are aiming to model soil structure and function in terms of crop rotation agricultural managements to define new soil health indexes that help farmers to take decisions on their agricultural soil managements to improve yield and soil health properties.

41 Harnessing Actinomycete Bacteria for Drug Discovery: from Bioprospecting to Synthetic Biology

Aprovechando a bacterias del orden Actinomycete para el descubrimiento de drogas: de la Bio- prospección a la Biología Sintética

Sergey B. Zotchev1. (1) Center of Pharmaceutical Sciences, Department of Pharmacognosy, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.

Although plants and higher fungi have been used by humans for ages as sources for new medicines, drug discovery from bacteria is a relatively new endeavor, its beginning dating back to 1940s. Since then, several decades of bioprospecting in the bacterial kingdom yielded many important anti-microbial and anti-cancer agents (e.g. tetracycline, vancomycin, nystatin, doxorubicin etc), although the rate of discovery declined steeply over the last 20 years. The main reasons for that were high costs of screening coupled to frequent re-discovery of already known bioactive molecules.

It has been demonstrated that certain types of bacteria, namely those belonging to the order Actinomycetales, are the most prominent producers of bioactive natural products. Today, although bioprospecting of actinomycetes still remains a viable source of new bioactive compounds, approaches based on post-genomic technologies open completely new possibilities for genome-based drug discovery. Actinomycetes’ genomes were shown to harbor dozens of orphan gene clusters that are silent under laboratory conditions, but can be activated via genetic engineering. The latter can also be used to alter natural product biosynthetic genes in order to generate new derivatives with improved pharmacological properties. Moreover, synthetic biology, a new discipline based on the use of engineering principles for the development of novel biological systems, can also be applied to harness bacteria for drug discovery.

In this presentation, examples of successful bioprospecting, genome mining, manipulation of natural products’ biosynthetic pathways, as well as synthetic biology-based approaches to engineering actinomycetes for drug discovery and development will be highlighted.

42

ORAL PRESENTATIONS

Looking for the mechanism of arsenate respiration in an arsenate-dependent growing culture independent of an ArrA

Respiración microbiana en cultivos que dependen del arsénico para crecer pero no de la presencia de la enzima ArrA

Mauricio Acosta Grinok1, Olga Encalada1, Lorena Escudero-González2, Nicolás Guiliani3, Cecilia Demergasso1. (1) Centro de Biotecnología, Vicerrectoría de Investigación , Universidad Católica del Norte (2) Centro de Investigación Científico-Tecnológica para la Minería (3) Laboratorio de Biología Celular y Molecular, Facultad de Ciencias, Universidad de Chile (Sponsored by Fondecyt 1100795 Y BHP Minerals Americas Project 32002137.)

The literature has reported the isolation of arsenate-dependent growing (ADG) microorganisms which lack a canonical homolog for respiratory arsenate reductase, ArrAB. Recently, we have isolated an ADG bacterium that is abundant in arsenic-bearing environments in Northern Chile. The aim of our work is to investigate the arsenic metabolism in the gram-positive isolate, Fusibacter ascotence (Fas). First results obtained by the use of uncouplers revealed that its growth is linked to the electron acceptor. The culture was able to grow on arsenate in the presence of an ionophore but not in the presence of a protonophore indicating that a proton gradient is essential for energy conservation. PCR experiments and genome sequence analyses revealed the lack of the membrane integral ArrAB coding genes. Moreover, genome comparison with other arsenic reducing microorganisms revealed the occurrence of Ferredoxin- NAD+ oxidoreductase (Rnf) coding genes, which are key molecular markers of the presence of a recently discovered mechanism involved in energy conservation and mostly associated with cytoplasmic enzyme complexes. Fas contains two putative cytoplasmic arsenate reductases with only 32% of identity in their aminoacidic sequences, and both of them belong to thioredoxin-coupled family. In order to assess the function of the gene products proposed to be involved in the arsenic metabolism, both arsC genes of Fas were cloned. A higher AsV resistance is conferred to the DarsC E. coli strain WC3110 by ArsC-2 compared to ArsC-1. These biological data are the first metabolic result needed for confirming the existence of the proposed metabolism in Fas.

Fondecyt 1100795

BHP Minerals Americas Project 32002137.

44 Microbial communities ensuring methanogenic potential at high salt concentration in marine sediments impacted by aquaculture

Comunidades microbianas con potencial metanogénico a altas concentraciones de sal en sedimentos marinos impactados por la acuicultura

Polette Aguilar1, Léa Cabrol2, Céline Lavergne1, Rolando Chamy1. (1) Escuela de Ingenieria Bioquimica, Pontificia Universidad Católica de Valparaíso (2) Mediterranean Institute of Oceanography (UMR 7294), CNRS/IRD, Campus de Luminy, Bâtiment Oceanomed, 13288 Marseille Cedex 9, France, Aix-Marseille Université

Methanisation (i.e. Anaerobic Digestion, AD) is an attractive bioprocess for the treatment and valorization of organic wastes. However, one of the challenge for AD of agroindustrial wastes is their high salt concentration that could inhibit the microbial actors of the system. We propose to use the methanogenic potential of natural consortia adapted to saline conditions. These consortia are presumably found in marine sediment, especially below salmon farming cages, where anoxic conditions and organic matter accumulation may favour methanogenesis. The objectives of this work are to determine the methanogenic potential of consortia from marine sediments impacted by aquaculture, and to evaluate the effect of salt concentration on methanogenic activity and microbial community structure.

We evidenced endogenous methanogenic activity in various aquaculture marine sediments, at variable magnitude depending on environmental parameters. High salt concentration (5 to 35 g L-1) did not inhibit the methanogenic activity. The active fractions of Archaea, Bacteria and methanogens were quantified through their 16S rRNAmcrA and transcripts. As expected, acetate spike resulted in increased mcrA expression. Through MiSeq sequencing of the 16S rRNA transcripts, we observed a clustering of microbial communities according to salt concentrations (dominated by Bacteroidetes, Cloacimonetes, Firmicutes and Proteobacteria), and the key OTUs for salt adaptation are currently identified.

The active methanogenic population was dominated by Methanogenium (in acetoclastic microcosms) and Methanocellus (in endogenic microcosms).

These consortia have an interesting biotechnological potential as inocula for AD of organic wastes generated by intensive aquaculture, which is an enviromental concern in the South of Chile.

45 Identity and temporal variability of ammonia-oxidizing activity in marine waters of Chile Bay, Antarctic

Identidad y variabilidad temporal de la actividad amonio-oxidante in Bahía Chile, Antártica

Maria Estrella Alcaman1,3, Jerónimo Cifuentes2, Beatriz Diez3,2, Laura Farias1,3. (1) Oceanografia, Ciencias Naturales y Oceanograficas, Universidad de Concepción (2) Genetica Molecular y Microbiologia, Ciencias Biologicas, Pontificia Universidad Católica de Chile (3) Centro del Clima y Resiliencia, CR2, Fisicas y Matematicas, Universidad de Chile

In Polar Regions, seasonal changes in taxonomic and functional diversity of marine microbial communities commonly occur in response to extreme changes in environmental conditions. Nitrification plays an important role in surface + nitrogen budgets through the stepwise oxidation of NH4 into nitrite and nitrate. Moreover, ammonia oxidation (AO) process has been measured in most oceans, however little is known in Polar Regions. Thaumarchaeota are abundant in Antarctic waters, and geochemical evidence suggests significant nitrification in Antarctic winter mixed layer. The main goal of this study was to evaluate the interannual (2018 to 2019) variability of bacteria (AOB) and archaea (AOA) ammonia-oxidizing diversity and activity (amoA genes) in surface (2m) and subsurface (30m) seawaters of Chile Bay (Greenwich Island, South Shetlands), and by mesocosms (SW+ICE) during the late summer season (February to March). Results show that Thaumarchaeota such as Nitrosopumilus and the bacterium Nitrosomonas were the most relevant AO microbes in the water profile, and in the mesocosms. A high amoA gene activity was measured by the number of transcripts (up to 1e3 gene-copies) and was related to the archaeon Nitrosopumilus in subsurface waters at 30m, while the activity of the ammonia-oxidizing bacteria (AOB) as Nitrosomonas was 3-times higher in surface 15 seawaters. Joint measurements of the AO and ammonia assimilation ( NH4Cl) rates will reveal how relevant the contribution of nitrification is as part of the nitrogen biogeochemical cycle in the seawaters of Chile Bay, and not just as a remineralization process but also by providing new inorganic nutrients for microbial communities.

Fondecyt Postdoctoral 3170807.

Centro de Ciencia del Clima y la Resiliencia (CR)2 FONDAP 15110009

46 Patterns of dissolved organic matter microbial degradation at an Atlantic coastal site

Patrones de degradación microbiana de la materia orgánica disuelta en un sitio costero en el Atlántico

María Cecilia Alonso1, Belén González1, Luciana Griffero1, Danilo Calliari1, Carolina Lescano1, Lorena Rodríguez1, Rudolf Amann2. (1) PDU Ecología Funcional de Sistemas Acuáticos, Centro Universitario Regional del Este, Universidad de la República (2) Molecular Ecology, Max Planck Institute for Marine Microbiology

A crucial process in the marine C cycle in coastal systems is the bacterial degradation of massive amounts of dissolved organic matter (DOM) derived from various sources. The environmental factors and community attributes controlling this process remain largely unknown. In this work, DOM biodegradation experiments were set along a year of regular sampling at the Uruguayan Atlantic coast. Incubations were run in triplicates for ca. 1 week, in a dark chamber at in situ temperature. Oxygen consumption in the experimental bottles was measured employing non-invasive optical sensors. At the beginning and end of each experiment, samples were taken to determine DOM quality, based on its spectral properties. Five patterns of biodegradation were identified through ordination, clustering, and partition methods. Most of the alterations in DOM after incubations related to molecular weight (MW), composition and colour, followed by humification, aromaticity, and oxygen consumed during biodegradation. The pattern encompassing most of the experiments was the one representing minor variations in DOM quality, accompanied by low to medium oxygen consumption. One outstanding pattern (pattern 5) resulted in a strong decrease in DOM MW and the maximal oxygen consumption. The occurrence of those patterns was linked to different environmental variables; e.g. pattern 5 occurred under the highest pH, the lowest salinity, the highest NO2, and the highest DOM MW. Furthermore, it was coincident with the maximal primary production rate, and one of the higher respiration rates. Thus, our results provide valuable information for understanding the factors controlling bacterial DOM degradation in the green seas. GIA ANII-MPI Recurrent bacterioplankton successions in coastal seas: an opportunity to evaluate taxonomy-based vs trait-based models for predicting ecosystem processes

47 Mineral based metabolisms and substrate acquisition mechanisms in acidic hydrothermal environments

Metabolismo de minerales y mecanismos de adquisición del substrato en ambientes hidrotermales ácidos

Maximiliano Amenabar1,2, Eric Boyd1. (1) Department of Microbiology and Immunology, Montana State University (2) Fundación Científica y Cultural Biociencia

Hydrothermal environments produce a wide array of redox-active minerals that can support microbial metabolisms including elemental sulfur (So), iron-(hydr)oxides, and arsenic sulfides. In many cases, the formation and fate of these minerals is a consequence of microbial activity, shaping the distribution, composition and activities of chemotrophic hot-spring communities. While substantial research has been conducted to uncover the ability of microorganisms to use So, few studies have focused on Fe(III) reduction in acidic high temperature ecosystems. In particular, a paucity of studies have focused on the interplay between the Fe and S cycles, despite the common co-occurrence of Fe and S minerals in these environments. Moreover, the ability to respire solid-phase minerals raises several questions including how these cells access these mineral substrates to support their metabolism. Specifically, it is not known how cells couple redox reactions that involve multiple solid-phase minerals when they serve as electron donor and acceptor [e.g., coupling So oxidation to iron-(hydr)oxide reduction]. Here we report a thermoacidophilic archaeon, isolated from an acidic hot-spring in Yellowstone National Park and designated asAcidianus strain DS80, that exhibits flexibility in its mineral-dependent energy metabolism. The energy metabolism of strain DS80 is supported by So, a variety of iron-(hydr)oxides, and arsenic sulfide. Strain DS80 reduced, oxidized, and disproportionated So. Our results indicated that the use of specific metabolisms (oxidative or reductive) in conjunction with a complex interplay of abiologically and biologically catalyzed reactions that increase the solubility or bioavailability of minerals, dictates the requirement for cells to access these minerals.

48 Disentangling the interaction between dissolved organic matter quality and bacterial degradation across Andean North-Patagonian freshwater networks (Argentina)

Desenredando la interacción entre la calidad de la materia orgánica disuelta y la degradación bacteriana en ambientes acuáticos andinos del norte de la Patagonia (Argentina)

Marcela Bastidas1, Esteban Balseiro1, Nicolás Martyniuk 1, Beatriz Modenutti1. (1) Laboratorio de Limnología, INIBIOMA (CONICET-UNCO) - Argentina (Sponsored by Consejo Nacional De Investigaciones Científicas Y Técnicas (CONICET))

Microbial degradation is one of the most important pathway by which dissolved organic matter (DOM) influence aquatic metabolism. As important as the amount of C-consumed by bacteria is the residual C-pool (molecules resistant to degradation that accumulate in the environments). Here we addressed how DOM composition and nutrients concentration (C, N, and P) affect C-consumption in Andean North-Patagonian networks (Argentina), andthe accumulation of C as residual. We combined field sampling of different aquatic ecosystems (deep, shallow, high altitude lakes, rivers, and wetlands) with DOM-lability experiments. We also analyzed different DOM sources (soil, benthic algae, macrophytes, senescent leaves leachates of different tree species) in order to track the probable origin of the DOM bulk. We observed a large variation in nutrient concentration across the different systems, being wetlands those with the widest range, and with the highest values. DOM characterization was performed by fluorescence excitation-emission matrices and analyzed with PARAFAC model. We identified 4 fluorescent components in DOM, three of which (C1, C3, and C4) had fluorescence emissions that resembled terrigenous-humic substances, and were particularly present in Nothofagus spp leachates. C2 showed fluorescence emissions similar to tryptophan (protein- like compound). Lability experiments showed that the proportion of residual C increased with the increase of dissolved N and the terrigenous C1, and decrease with increasing dissolved P concentration. High C1 was also related with low C-specific consumption. Our results showed that the highest inputs of DOM of terrigenous origin, associated also with higher N concentrations, favor DOM accumulation in the environments.

Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Fondo para la Investigación Científica y Tecnológica (FONCYT) - PICT 2015-2138, PICT 2016-2019, PICT 2018-2020

49 Deciphering a membrane fusion mechanism in archaeal viruses

Descifrando un mecanismo de fusión de membranas en virus de arqueas

Eduardo Bignon1, Felipe Hurtado1, Elina Roine2, Nicole Tischler1. (1) Molecular Virology , Fundación Ciencia & Vida (2) Laboratory of Structural Biology, Helsinki Institute of Life Science HiLIFE and Molecular and Integrative Biosciences Research Program, University of Helsinki

Membrane fusion is a fundamental process in all domains of life but still little information exists in prokaryotic systems, especially archaea. Recently in the archaea domain, the structure of the viral envelope protein VP5 was determined for two haloarchaeal pleomorphic viruses (HRPV-2 and HRPV-6). This family of archaeal viruses possess a lipid membrane with only the VP5 protein forming the viral spike protrusions, making it an ideal candidate for a membrane fusion protein. Here we aimed to determine whether pleolipoviruses infect their archaeal hosts by membrane fusion and if VP5 drives this process. Therefore, we first measured lipid mixing between the viral membrane and its host cell Halorubrum sp. SS7-4 using fluorescence de-quenching of a lipophilic dye. We found that lipid mixing only occurred with specific host cells of the virus and that this process was blocked by protease digestion of the viralsurface proteins, suggesting that lipid mixing was driven by VP5. We further established a cell-free target membrane system by using liposomes prepared from archaeal lipids. Consistent with the absence of cellular receptors, no membrane fusion occurred spontaneously. We only detected viral-liposome lipid mixing when we increased the temperature to 55°C, reported to decrease HRPV infectivity. Taken together, our results show that VP5 from HRPV is a viral membrane fusion protein driving the infection of host cells and that this protein can be specifically triggered by incubation at high temperature. Characterization of the fusion mechanism with archaeal cells is the aim of our current studies.

Funding: Grant FONDECYT postdoctoral 3190415 to EB and Programa de Apoyo a Centros con Financiamiento Basal AFB 170004 to Fundación Ciencia & Vida

50 Identification and characterization of antimicrobial peptides of the skin Patagonian frog P. somuncurense (anura: Leptodactylidae: Leiuperinae)

Identificación y caracterización de péptidos antimicrobianos de la piel de la rana patagónica Pleurodema somuncurense (Anura: Leptodactylidae: Leiuperinae)

Natalia Lorena Cancelarich1, Daniel Carneiro Moreira2, Eder Alves Barbosa3,4, Alexandra Plácido5,8, Luis Orlando Pérez6, Néstor Guillermo Basso7, A. Leite Jose Roberto Souza2,8, Mariela Mirta Marani1. (1) IPEEC-CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina. (2) Área de Morfologia, Faculdade de Medicina, Universidade de Brasília (UnB), Brasília, Brasil (3) Laboratório de Espectrometria de Massa, EMBRAPA Recursos Genéticos e Biotecnologia, Brasília, Brasil (4) Laboratório de Síntese e Análise de Biomoléculas, Instituto de Química, UnB, Brasília, Brasil (5) LAQV/REQUIMTE, Faculdade de Ciências , Universidade do Porto (UP), Porto, Portugal (6) IPCSH - CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina (7) IDEAus - CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina (8) Instituto de Investigação e Inovação em Saúde e Instituto de Biologia Molecular e Celular (IBMC), UP, Porto, Portugal

Actualmente la resistencia a los antibióticos es una de las mayores amenazas para la salud. La aparición y propagación de bacterias multirresistentes requiere la búsqueda de nuevas moléculas terapéuticas para combatirlas. En este sentido, los péptidos antimicrobianos (PAMs) han demostrado ser efectivos contra un amplio espectro de microorganismos. El objetivo de este trabajo fue la identificación de PAMs de la piel de la rana patagónica Pleurodema somuncurense. Se extrajo el ARNtotal de la piel de P. somuncurense, se obtuvieron los ADNc específicos que se transfectaron y clonaron en células competentes. Se secuenciaron 11 insertos y, mediante análisis in silico de las secuencias aminoacídicas de los prepro-péptidos obtenidos, se sintetizaron y purificaron 8 péptidos maduros empleando química F-moc y RP-HPLC respectivamente. Se evaluó la actividad antimicrobiana contraEscherichia coli (ATCC 25922) y Staphyloccocus aureus (ATCC 29213). Se determinó la actividad hemolítica y se estudió su estructura secundaria por dicroísmo circular (DC). Dos de los péptidos inhibieron el crecimiento de E. coli (CIM=600-500 µg/mL) y uno inhibió tanto el crecimiento de E.coli (CIM=250-125 µg/ml) como el de S. aureus (CIM=500-250 µg/mL). La actividad hemolítica fue baja en los tres casos. Los resultados de DC mostraron que al aumentar la concentración de TFE la tendencia a adquirir una conformación de tipo α-hélice aumenta. Este trabajo contribuye a la identificación de nuevas moléculas demostrando la importancia de la bioprospección y descripción génica de las especies y la conservación de la biodiversidad, entendiendo a la Naturaleza como fuente primordial de nuevos agentes terapéuticos.

Esta investigación se enmarca dentro de los proyectos CONICET PIP no. 11220120100050OC y PUE-CONICET N°22920160100044 (MMM). NLC agradece a CONICET por la beca doctoral otorgada.

51 Antimicrobial Resistance Genes in wild foxes inhabiting human dominated landscapes

Genes de Resistencia Antimicrobiana en zorros salvajes que habitan paisajes dominados por el ser humano

Aitor Cevidanes1, Fernando Esperón2, Sophia Di Cataldo1, Claudia Ulloa3, Irene Sacristán1, Elena Neves2, Nicole Sallaberry-Pincheira1, Javier Millán 1. (1) Universidad Andrés Bello (2) INIA, España (3) Universidad de Chile

Antimicrobial resistance (AMR) is considered an emerging problem spreading in a high variety of habitats. The greater AMR development rate is associated with “antibiotic-using” environments. Therefore, wildlife inhabiting could be good sentinels to analyze the burden of AMR on anthropized landscapes. Foxes living in rural areas could come into direct or indirect contact with human wastes and, may also acquire bacteria with antibiotic resistance genes (ARGs) through consumption of preys or during carcass scavenging. The aim of this study was to determine the presence and to quantify ARGs related to resistance against 8 antibiotic families in Lycalopex culpaeus fox feces, from Central Chile. DNA was extracted from rectal swabs from 72 foxes and 22 ARGs were evaluated using qPCR. Additionally, two foxes that were kept 6-7 days in a clinical environment (a Wildlife Rescue Center). Eighteen of the ARGs were found in at least one sample. tetQ and tet W were the most common (65.3% and 54.2%, respectively). The average of ARGs detected per sample was 3.8 (range 0-9). In addition, 47.2% of the foxes presented a “multiresistant microbiome”. Of the two rescued foxes, as much as 15 and 13 ARGs were detected in their faecal samples. The occurrence of ARGs in the present study can be considered very high when compared to similar studies. The effect of AMR in wildlife is unclear, but wild foxes seem to be good sentinels for ARGs environmental burden. Wildlife kept at rescue centers could be sources of ARGs when returned to the environment.

Fondecyt Regular 1161593 (CONICYT, Chile)

52 Know your enemy: Microbial dynamics, networks and other insights into a corrosive biofilm

Conoce a tu enemigo: Dinámicas microbianas, redes y otras historias sobre una biopelícula marina

Leslie K. Daille1,2,3, Ignacio T. Vargas2,3, Rodrigo De La Iglesia1,3. (1) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Departamento de Ingeniería Hidráulica y Ambiental, Facultad de Ingeniería, Pontificia Universidad Católica de Chile (3) Marine Energy Research & Innovation Center (MERIC)

Biocorrosion is an electrochemical phenomenon influenced by the activity of microorganisms within a complex biological matrix on the liquid-metal interface, known as a biofilm. After the establishment of the first specie that colonize the metal, a microbial succession is triggered, associated with the development of specific interactions between microorganisms and the microenvironments of the biofilm. Despite the importance of microorganisms in marine biocorrosion, it is still not clear which microorganisms will settle on the surface, how they affect the constitution of the biofilm on metal surfaces and what their corrosive capacity depends on.

The aim of this study was to determine the microbial dynamics and interactions within a marine biofilm-associated to biocorrosion. To accomplish this goal, a time series experiment was designed with exposure of stainless steel coupons to natural seawater in a running-seawater laboratory during 15 weeks of aging. Biofilmcharacterization was performed by electron scanning microscopy and Illumina high-throughput sequencing analysis of SSU rRNA gene (bacteria, archaea, and eukaryotes). Subsequently, network co-occurrence analysis was inferred per each sampling time.

Biofilm characterization revealed a dynamic assembly of the biofilm through time, with the participation of archaea and picoeukaryotes since early times of exposure. Besides, its corrosive behavior showed patterns correlated to potential ecological interactions within the biofilm. Our results suggest that the biofilm acts as a biological unit with corrosive potential, which depends on the ecological interactions that are established during its assembly, rather than as the result of the presence of a particular group of microorganisms.

Funded by Marine Energy Research & Innovation Center (MERIC) (Project CORFO 14CEI2-28228), Office Naval Research (Grant NICOPN62909-17-1-2012) & Beca de Doctorado Nacional CONICYT-PCHA/2014-21140415.

53 Deciphering the Amazon floodplains microbial community structure and its interactions networks

Descifrando la estructura de la comunidad microbiana de las llanuras de inundación del Amazonas y sus redes de interacciones

Michaela De Melo1, Stefan Bertilsson2, Dolly Kothawala2, João Henrique Amaral3, Bruce Forsberg3, Hugo Sarmento1. (1) Departamento de Hidrobiologia, Universidade Federal de São Carlos (2) Department of Ecology and Genetics, Uppsala University (3) Coordenação de Dinâmica Ambiental, Instituto Nacional de Pesquisas da Amazônia

Amazonian floodplain systems (AFS) comprise a dynamic mosaic of heterogeneous habitats that host ahuge biodiversity of animals, plants and microbes. Heterotrophic bacteria in these systems play key role in organic matter degradation, affecting regional carbon budgets and biogeochemical cycles. Yet, there is a lack of information of the mechanisms that shape bacterial community composition (BCC) in these complex ecosystems. Applying 16S rRNA gene amplicon high-throughput sequencing, we studied the BCC in an AFS (lake Janauacá - 3°23›S/60°18›W), and determined the effect of dispersal processes, environmental filtering and biotic interactions in assembling these communities. Our results pointed out that the flood pulse is the main driver of BCC, since it regulates the water exchange and connectivity with the main river channel, which ultimately impact in microbial dispersal. Moreover, there was a clear seasonal pattern in BCC, closely related to environmental variables such as the origin, molecular weight, and aromaticity of the dissolved organic matter, suggesting that the successful establishment of dispersing bacteria also depends on environmental filtering that is linked to water flow. The interactions network inferred from sparse correlations for compositional data, resulted in highly connected operational taxonomic units (OTUs, average degree of 7.994), a modular community structure (M=0.522) and a non-random organization, as demonstrated by higher topological properties comparing the observed network with random networks. Overall, our results elucidated the mechanisms that shape BCC and microbial degradation of the dissolved organic matter in an AFS throughout seasonal fluctuations in the water level.

54 Versatile methane consumers with smmo enzymes are reduced in amazon forest soils after deforestation and pasture establishment

Los metanótrofos versátiles con enzimas smmo disminuyen en suelos amazonicos como consecuencia de la deforestación y el establecimiento de pastizales

Leandro Fonseca De Souza1, Dasiel Obregon1, Fabiana De Souza Cannavan1, Klaus Nüsslein2, Siu Mui Tsai1. (1) Center for Nuclear Energy in Agriculture, University of Sao Paulo (2) Microbiology Department, University of Massachusetts - Amherst (Sponsored by FAPESP (2018/09117-1 And 2014/50320-4), CNPq (140953/2017-5) And CAPES (001 And 88881.189492/2018-01))

Methanotrophic bacteria are the only known biological sink for this greenhouse gas. They convert methane to methanol via methane-monooxygenase, which can be integrated into their membranes (pMMO) or soluble in their cytoplasm (sMMO). Here we evaluated the effect of deforestation of Amazon rainforest and establishment of pastures on these microbial communities. Topsoils (0-10 cm) were sampled in Primary Forest and Pasture areas (45 years after conversion) in Southwestern Amazon – Brazil. Extracted DNA was analyzed by high throughput sequencing (HiSeq 2500 v4) and specific functional genes were quantified by qPCR (pmoA and mmoX). Also, soil bulk chemistry (pH, O.M., N, P, K, S, Ca, Al, Fe, Cu, Mn, Mg and Zn contents) and methane fluxes were evaluated by gas chromatography (SRI 8610C). We found Forest soils to be a sink for methane (-70 ± 30 μg.m2.h-1) while pastures were a source (25 ± 30 μg.m2.h-1). Certain methanotrophs decreased with land use change: Methylocella spp. two-fold, and Methylococcus spp. and Methylosinus spp. 20-50%, with no significant changes (p<0,05) in Methylaciphilum spp. The only change in methanotrophic gene relative abundancies was mmoX-a, which decreased by half in pastures. This decrease was confirmed by qPCR quantification. These shifts may be related to higher Copper levels in pastures, known to regulate pmoA and mmoX expression in vitro, but lacking studies in soils. The decrease of sMMO methanotrophs in pasture soils may impact the resilience of the system since these methanotrophs are less versatile in dealing with other C1 compounds, variable methane concentrations, and copper-poor soils.

FAPESP (2018/09117-1 and 2014/50320-4), CNPq (140953/2017-5) and CAPES (001 and 88881.189492/2018-01)

55 Heavy metal contamination in Brazilian Port Areas and the relationship with the microbial community: the pollution in these areas can change the microbial community?

Contaminación por metales pesados en áreas portuarias brasileras y su relación con la comunidad microbiana: ¿puede la contaminación en estas áreas cambiar la comunidad microbiana?

Bruna Del Busso Zampieri1, Da Costa Andrade Vanessa1, Merguizo Chinellato Roberta1, Alexandre Borges Garcia Carlos2, Antonio Oliveira Marcos1, Brucha Gunther3, Fernandes Cardoso De Oliveira Ana Julia1. (1) Universidade Estadual Paulista”Júlio de Mesquita Filho” (2) Universidade Federal de Sergipe (3) Universidade Federal de Alfenas

Port activities are associated with the spreading of different contaminants in environmental compartments. One of the most important impacts associated with port areas is the increase of heavy metals concentration. Metal pollution can lead to severe changes in community structure and composition, and select groups can develop resistant mechanisms. Thus, the aim of the present study was to analyze how heavy metals influence the bacterial community in Brazilian port areas and the selection of resistant strains comparing to a pristine area. The community composition changed between the two port areas and pristine area. Proteobacteria, Cyanobacteria, and Thermodesulfobacteria were the phyla that showed a weak positive correlation with organic contamination and with Cu and Zn. Chloroflex, Nitrospirae, Planctomycetes, and Chlorobi showed a negative correlation to Cu, Cr, and Zn. Microbial groups involved in the nitrogen cycle and that can degrade one-carbon compounds were found in lower abundance at port areas. The diversity was lower in the port areas comparing to the Pristine area. However, it was not possible to see clearly a higher amount of heavy metal resistant strain in port areas comparing to the control area. On the other hand, it was possible to notice that some genera can develop easily heavy metal resistant mechanisms, which is why the most isolated genera were Bacillus sp, Vibrio sp, and Pseudomonas sp. This kind of study makes clear how pollutants can influence the community as a whole in complex natural environments and the further consequences of those changes.

Coordination for the Improvement of Higher Education Personnel (CAPES)

56 The Microsetta Initiative: A Global Microbiome Framework for the American Gut Project

La Iniciativa Microsetta: Un Marco Global del Microbioma en el Proyecto American Gut

Edgar Diaz1, Daniel McDonald1, Alexander Aksenov2, Alexey Melnik2, Pieter Dorrestein2, Rob Knight1. (1) Department of Pediatrics, School of Medicine, University of California, San Diego (2) Departments of Pharmacology and Pediatrics, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego

The American Gut Project (AGP) was launched as a crowdfunded citizen science effort in 2012 to assess the scope of microbial diversity associated with humans through the lens of the 16S rRNA gene and to establish an open-access discovery cohort. Using minimal exclusion criteria, cost reductive methodologies and standardized collection kits, AGP allowed virtually anyone to participate. These approaches enabled AGP to gather samples (mostly fecal) from over 20,000 individuals, uncovering a collection of previously unrecognized diversity, and discovering novel associations with lifestyle, diet, and health. When placed in the data frame of the Earth Microbiome Project, we observed that the breadth of diversity from fecal samples alone became readily apparent, underscoring our continued limited knowledge of our microbial inhabitants. By applying HPLC-MS to a subset of fecal samples, we observed a wealth of small molecule diversity mediated by lifestyle choices. Having scaled the infrastructure across the United States, the United Kingdom, and Australia, we are now expanding to the broader international community to assess what microbial factors translate between populations. Here we introduce The Microsetta Initiative, the next phase of this highly collaborative effort, with an emphasis on global inclusion, standardization of technical practices, and utilization of modern molecular methodologies including shallow shotgun sequencing and HPLC-MS. This transition emphasizes engagement with underrepresented populations both at the local level (e.g., limited disposable income populations) and global scale (e.g., Latin America), and expansion of the availability of population-specific microbiome references to improve the interpretation of regional studies.

57 Microbiota Modulates Intestinal Regeneration

La Microbiota Modula la Regeneración Intestinal

Lymarie M. Díaz-Díaz1, Natalia Rosario-Meléndez1, Ángela M. Colón-Cruz1, Sergio M. Maldonado-Chaar1, Omar A. Pérez-Villafañe1, José E., Ph.D. García-Arrarás1. (1) Biología, Ciencias Naturales, Universidad de Puerto Rico, Recinto de Río Piedras

Special attention has been given to microbiota roles associated with digestive tract function. Studies have focused on the regeneration of the intestinal luminal epithelium. We now use a novel model system, the sea cucumberHolothuria glaberrima to explore the microbiota role on the regeneration of the complete organ. For this, sea cucumbers were eviscerated and left to regenerate in seawater with different antibiotics (cocktails of Penicillin/Streptomycin (PS), Erythromycin (EryPS) or Kanamycin (KanPS)) for ten days. Immunohistochemistry was used to analyze the regenerative events, such as growth, extracellular matrix (ECM) remodeling and muscle dedifferentiation. Organisms treated with EryPS displayed a significant reduction in the size of the regenerating intestine. In addition, they showed increased collagen labeling in the rudiment suggesting a delayed clearance of this ECM components. In addition, a reduction in muscle dedifferentiation was observed in animals treated with either EryPS or KanPS. These results indicate a delayed regeneration in animals with altered microbiota as a result of treatment with the antibiotic cocktail. To rule out the possibility that the antibiotics are having a direct effect on holothurian tissues, we used the MTT assay technology to measure the cellular activity in tissue explants. Our results suggest that the tested antibiotics concentrations do not disturb the metabolism of holothurians tissues. In summary, we can point to the microbial community as an important player in modulating the regeneration of the intestine and present H. glaberrima as a promising model to study the importance of the microbiota during organ regeneration.

This project was funded in part by PRSTRT grant #20270.001.000.XXXX.220.206350070017.00 and RISE grant #5R25GM061151.

58 Microbial diversity drives carbon use efficiency in a model soil system

La diversidad microbiana afecta la eficiencia del uso del carbono en un suelo artificial

Luiz Domeignoz1, Grace Pold2, X.J.A. Liu3, J.M. Melillo4, S.D. Frey5, K.D. DeAngelis3. (1) Microbiology, University of Massachusetts (2) Graduate Program in Organismic and Evolutionary Biology, University of Massachusetts (3) Department of Microbiology, University of Massachusetts (4) Ecosystems Center, Marine Biological Laboratory (5) Department of Natural Resources and the Environment, University of New Hampshire

Soils contain the largest organic carbon pool in the terrestrial biosphere and represent an important source of carbon dioxide (CO2) to the atmosphere. Microbial carbon use efficiency (CUE) – or the fraction of C taken up by a cell that is converted to biomass – is a central determinant of how much carbon is able to be retained in soil. CUE has been proposed to vary with both biotic and abiotic conditions, but it remains elusive how this pivotal variable inthe C cycle is responding to the dually changing climate and biodiversity. The present study addressed how microbial diversity, community composition, temperature and moisture impact CUE. We extracted soil microbial communities from a mixed deciduous forest, manipulated them to generate distinct diversity levels, and inoculated them into a model soil. We evaluated CUE using the 18O-H2O method, and the diversity of bacteria and fungi by sequencing the 16S rRNA and ITS genes. Abiotic factors affected CUE primarily through shifts in the microbial community. Bacterial community structure and bacterial alpha diversity were the strongest drivers of CUE, with standardized SEM path coefficients of 0.49 and 0.4, respectively. Interestingly, drought disrupted the relationship between CUE and bacterial alpha diversity, such that there was a positive correlation between bacterial phylogenetic diversity and CUE under moist conditions (rho: 0.45, P<0.001), but no relation in the communities formed in dry soils. Altogether, these results indicate that microbial community composition, diversity and abiotic factors interact to drive changes in CUE, with yet-unknown effects on soil carbon cycling.

Department of Energy contract DE-SC0016590

59 Effect of climate change on microbial communities of altiplanic salares of northern Chile

Efecto de cambio climático en las comunidades microbianas de salares altiplánicos del norte de Chile

Cristina Inés Dorador1, Verónica Molina2, Martha Hengst3, Yoanna Eissler4, Marcela Cornejo5. (1) Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (2) Programa de Biodiversidad and Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha de Ciencias de la Educación (3) Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte (4) Centro de Investigación y Gestión de Recursos Naturales, Instituto de Química y Bioquímica, Facultad de Ciencias, Universidad de Valparaíso (5) Escuela de Ciencias del Mar e Instituto Milenio de Oceanografía, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile

Chile es un país altamente vulnerable al cambio climático, siendo la biodiversidad una de las áreas más afectadas. Los ambientes considerados extremos generalmente están dominados por microorganismos que presentan adaptaciones únicas para prevalecer bajo distintos tipos de estresores ambientales. Sin embargo, su rol e importancia en temas de adaptación al cambio climático ha sido poco estudiado. Específicamente para el Salar de Huasco se ha determinado que al año 2100 las temperaturas medias mensuales y diarias aumentarán, presentándose en el escenario más extremo, aumentos de hasta 4,5°C de temperatura diaria. Para el caso de la precipitación, la variabilidad diaria y estacional disminuirá y se presentarán con mayor frecuencia eventos extremos de precipitación de hasta 57,6 mm/ día. Por otro lado, se ha determinado que en salares el ciclaje de gases de efecto invernadero (GHG) se realiza por una comunidad microbiana activa en agua y tapetes microbianos, los cuales a su vez actuarían como una barrera mecánica de acumulación de GHG. En este trabajo se analizaron los servicios ecosistémicos microbianos de distintos ambientes acuáticos extremos del norte Chile y se realizó un análisis de escenarios futuros de cambio climático en el Altiplano respecto a las comunidades microbianas. Para el caso del Salar de Huasco, se determinaron los servicios ecosistémicos microbianos de soporte, regulación y cultural. En particular, se propone que el aumento de temperatura y de eventos extremos de precipitaciones en salares del Altiplano producirá una perturbación de las comunidades microbianas afectando directamente el ciclaje de CH4, CO2 y N2O. Es decir, la pérdida de tapetes microbianos favorecería el aumento de emisiones de GHG desde el humedal hacia la atmósfera, ya que los tapetes son mitigadores de dichas emisiones. Es crucial generar estrategias de preservación de salares para ayudar a mitigar las emisiones de GHG y favorecer la captura de CO2.

60 Dynamics and function of microbial communities involved in methane cycle in rice crop rotation systems

Dinámica y función de las comunidades microbianas del ciclo del metano en suelos de arrozales en diferentes sistemas de rotación

Ana Fernández1. (1) Laboratorio de Ecología Microbiana Medioambiental, Biociencias, Facultad de Química, Universidad de la República, Uruguay

The cultivation of irrigated rice has a strong environmental impact since two thirds of its cycle occurs under anaerobic conditions generating emissions of methane (CH4). This greenhouse gas is produced by anaerobic decomposition of organic matter by fermentative bacteria followed by methanogenic archaea. Methane can also be consumed by aerobic methanotrophic bacteria present in rice paddy soils. Therefore, methane emission during rice cultivation depends on the redox potential of the soil, nutrients availability and microbial community structure. The rotation with upland crops, introduced recently to improve sustainability of rice production, may change the carbon availability and the structure of microbial populations involved in methane emission during rice cropping. In this work, the community structure was studied by amplicon sequencing of the 16S rRNA gene (MiSeq plataform) and qPCR of specific genes (mcrA and pmoA). The methane flow was determined at the field in static chambers by GC measurements and the rate for methane production or consumption was analyzed in microcosms assays. The flow of CH4 was affected by the previous use of the soil, mainly at early steps of the rice cropping. This effect was also observed on the abundances of methanogenic and methanotrophic populations, thought these populations reached similar densities in all soils after weeks of flooding. Nevertheless, the bacterial community composition was slightly affected by the previous use of the soil. In general, the community structure and function parameters measured showed that the crop rotation influenced the methane cycle populations mainly at early stages of rice cropping.

Comisión Sectorial de Investigación Científica, CSIC, Universidad de la República. Uruguay

Agencia Nacional Investigación e Innovación, ANII, Uruguay. Fondo INNOVAGRO

Programa de Desarrollo de Ciencias Básicas, PEDECIBA, Uruguay

61 Molecular characterization of salt bacteria of the lagoons of the north of peru and evaluation of its bioactive potential against different types of tumor cells

Caracterización molecular de bacterias salinas de las lagunas del norte del perú y evaluación de su potencial bioactivo contra diferentes tipos de células tumorales

Rene Flores Clavo1, Alvaro Jose Hernandez Tasco 2, Nataly Ruiz Quiñonez 3, Ana Lucia Tasca Gois Ruiz 4, Lucia Elaine De Oliveira Braga 5, Marcos José Salvador2, Fabiana Fantinatti Garboggini6. (1) 4Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil., INSTITUTO DE BIOLOGIA, UNIVERSIDAD ESTADUAL DE CAMPINAS-UNICAMP (2) 2Department of Plant Biology Bioactive Products of the Institute of Biology, University of Campinas, INSTITUTO DE BIOLOGIA, UNIVERSIDAD ESTADUAL DE CAMPINAS (3) Microbial Resources Division, Research Center for Chemistry, Biology and Agriculture (CPQBA), University of Campinas- Sao Paulo- Brazil, INSTITUTO DE BIOLOGIA, UNIVERSIDAD ESTADUAL DE CAMPINAS (4) 3Faculty Pharmaceutical Sciences, Institute of Biology, University of Campinas, Campinas, SP, Brazil, FACULTAD DE FARMACIA, UNIVERSIDAD ESTADUAL DE CAMPINAS (5) 3Faculty Pharmaceutical Sciences, Institute of Biology, University of Campinas, Campinas, SP, Brazil,, FACULTAD DE FARMACIA, UNIVERSIDAD ESTADUAL DE CAMPINAS (6) 4Graduate Program in Genetics and Molecular Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil., INSTITUTO DE BIOLOGIA, UNIVERSIDAD ESTADUAL DE CAMPINAS he Salinas lagoons of the North of Peru are geoforms, characterized by depressions or subsidence of the coast of the Pacific Ocean. Saline habitats are considered as extremophilic and halophilic environments due to the presence of salts in water and soil, the main ones being chlorides, followed by sulfides, bicarbonates and bromides of magnesium, calcium and potassium. Sodium chloride, commercially known as common salt, is exploited by the population living in these areas. The present study aimed to isolate and taxonomically characterize bacteria present in the Salinas de Mórrope and Bayovar lagoons and to evaluate the antiproliferative activity of the crude extracts and their fractions of these microorganisms against different tumoral strains. 211 bacteria were isolated, of which 166 were reactivated and characterized morphologically and 52 were identified by sequencing and phylogenetic analysis of the 16S ribosomal RNA gene. The molecular identification grouped the bacteria in the genera Streptomyces (n = 39), Pseudonocardia (n = 3), Staphylococcus (n = 4), Pseudomonas (n = 2) and Bacillus (n = 2). Twenty-three crude extracts were obtained from the microbial growth and liquid-liquid extraction with the ethyl acetate solvent (AcOEt) for antiproliferative tests with Sulforhodamine B (SRB) against tumor lines. The isolates M-92, B-146, B-81 and B-8 belong to the genus Streptomyces and showed promising results against the following tumor cells: U251 glioma; MCF7 breast; NCI-H460 non-small cell lung type.

ESTE PROYECTO FUE FINANCIADO CON UNA BOLSA DE ESTUDIANTE DE MAESTRIA POR EL CNPQ.

62 Consistent response of microbial communities facing hydrocarbons in Antarctic soils

Respuesta consistente de las comunidades microbianas frente a hidrocarburos en suelos antárticos

Sebastián Fuentes1, Beatriz Díez1. (1) Departamento de Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica De Chile

Due to abiotic limitations, most ecological processes in Antarctic soils are driven by microorganisms. Anthropogenic disturbances can impair community stability and, eventually, their ecological functions. The present research focuses on hydrocarbon pollution – the disturbance model – over Antarctic soil microbial communities – the system model – using total-community 16S and 18S rRNA gene sequencing, hydrocarbon quantification and soil physicochemistry. In soils from South Shetland Islands and Antarctic Peninsula, hydrocarbon pollution was one of the main drivers of both Bacteria/Archaea and Eukarya diversity. Bacterial sequences related to Actinobacteria and Alphaproteobacteria were enriched in polluted sites, particularly a Williamsia sp. which accounted for ~25% of the bacterial community in heavily-polluted sites. Similarly, fungal sequences related to Leotiomycetes and Microbotryomycetes accounted for ~60% of the eukaryotic community in heavily-polluted sites. Those patterns were consistent across sites sampled kilometers far from each other. Soil microcosm experiments were used to weight the influence of community history on the stability after diesel pollution under simulated summer and winter conditions. The community from a chronically- polluted soil was more stable, in terms of beta-diversity, than a community from a pristine soil. Consistent with the sampling results, several Actinobacteria and Alphaproteobacteria taxa increased in relative abundance, whereas other taxa responded negatively. A diesel dose-dependent pattern was observed for the pristine soil during summer and for the chronically-polluted soil during winter. Altogether, our results suggest that the same disturbance can reach predictable communities across sites kilometers distant and the stability is higher in communities previously exposed to disturbances of similar nature.

FONDECYT Postdoctoral 3160424, INACH RG_09-17, CONICYT DPI20140044, FONDAP N°15110009

63 Copper Pollution: Picoeukaryote plankton responses to copper enrichments in changing modern ocean

Polución por cobre: Respuesta del plancton picoeucarionte a enriquecimientos por cobre en un cambiante océano moderno

Benjamín Glasner1, Isidora Morel1, Esteban Osses1, Fernando Alfaro3, Jean-Claude Lozano4, Valerie Vergé4, Santiago Andrade2, François-Yves Bouget4, Nicole Trefault3, Rodrigo De La Iglesia1. (1) Departamento de Genética molecular y microbiología, Facultad de Ciencias Biológicas, Av. Portugal, Santiago. Chile, 8330025, Pontificia Universidad Católica de Chile (2) Departamento de Ecología, Facultad de Ciencias Biológicas, Av. Portugal, Santiago. Chile, 8330025, Pontificia Universidad Católica de Chile (3) GEMA Center for Genomics, Facultad de Ecología y Medio ambiente, Camino La Pirámide 5750, Huechuraba, Santiago. Chile, 8580745, Universidad Mayor (4) Laboratoire d´Océanographie Microbienne (LOMIC), Observatoire Oceanologique de Banyuls-sur-mer, Av. Pierre Fabre, Banyuls-sur-Mer. France, 66650, Sorbonne université

Coastal environments are of special importance for human development. In these regions roughly half of total primary production take place, representing an important system for earth biogeochemistry and a fundamental region to ecosystemic services. However, these systems are subjects to constant pressure due to environmental variability from natural or anthropogenic sources, where human-made disturbances and chemical pollution lead to constant challenges for organisms physiology and ecological processes. The photosynthetic fraction of the planktonic microorganisms plays a key role in environmental functioning and biogeochemical processes. Within this functional group, small size organisms are getting increasing interest related to their unknown diversity and ecological relevance. Here, with remote and infield observations and highly replicated experiments at community and population levels, we evaluated the effects of copper as a relevant environmental pollutant over the abundance and composition of Picoeukaryote phytoplankton. Our analysis showed that copper act as a homogenizing force to biological diversity among picoeukaryotic communities, by decoupling biotic aspects of abiotic seasonal fluctuations incoastal communities that leads to a particular microbial community structure. Moreover, picoeukaryotic communities exposed to copper pollution showed consistent responses in terms of abundances, where Mamiellophyceae clade showed differential susceptibility. When functional response at protein level in model organism Ostreoccocus tauri was tested, ion homeostasis and nitrogen cycling transport systems were responsive in concentration-dependent manner. Our data suggest crossed regulation among metal homeostasis and nitrogen metabolism with potential ecological and biogeochemical effects and emphasize potential role of Mamiellophyceae clade as a sentinel group of changes in coastal environments.

64 Integrative Genomics Sheds Light on Microbial Evolutionary Mechanisms in Extremely Acidic Environments

Genómica Integrativa clarifica los mecanismos evolutivos microbianos en ambientes extremadamente ácidos.

Carolina González1,2, Eva Vergara2, Gonzalo Neira2,3, Jorge Valdés1, David S. Holmes1,2. (1) Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor (2) Center for Bioinformatics and Genome Biology, Fundación Ciencia & Vida (3) Universidad de Chile

Analysis of robust and coherent phylogenies of four extant hyper-acidophilic bacterial genera (pH <3), Leptospirillum, Acidithiobacillus, Methylacidiphilum and Methylacidimicrobium, from different early and late branching lineages distributed around the Tree of Life, suggest that they evolved from ancestral neutrophiles. Examination of these phylogenies, coupled with comparative genomicssheds light on how extreme acidophilia evolved, highlighting the stepwise accumulation of mutations, acquisition of genes by horizontal gene transfer (HGT) and expansion into novel habits that both challenged (e.g. need for heavy metal resistance), and provided new opportunities (e.g. for iron oxidation, diversification of sulfur metabolism and nitrogen fixation). Some important aspects of the results are the acquisition of genes and pathways for membrane stabilization at low pH and the presence of a large pool of accessory genes with functional redundancy that provide the opportunity to “hedge bet” in rapidly changing acidic environments, where it is hypothesized that the cost of maintaining genetic redundancy is offset by the ability to expeditiously adjust to environmental fluxes. All four acidophilic genera are aerobes, although three of them contain facultative anaerobic representatives. One hypothesis is that the origin of acidophiles and/or their dispersal is linked to the rise of free oxygen around the time of the Great Oxygenation Event (GOE) about 2.2 billion years ago.

This work was supported by Fondecyt Postdoctorado 3190792, Fondecyt 1181717, Programa de Apoyo a Centros con Financiamiento Basal AFB 17004 to Fundación Ciencia & Vida

65 Marine Fungi, evidence for their presence and activity in waters of the coastal ocean off Chile

Hongos marinos, evidencias para su presencia y actividad en aguas del océano costero frente a Chile

Marcelo H Gutiérrez1,2, Silvio Pantoja1,2. (1) Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad De Concepción (2) Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad De Concepción

Aunque en los últimos años el conocimiento sobre hongos marinos ha incrementado, éstos aun permanecen como uno de los grupos funcionales de microorganismos menos conocidos en el océano. Uno de los mayores problemas que ha enfrentado su estudio es que la presencia de hongos en el océano ha sido atribuida a un origen terrestre. Esto se debe a que las aproximaciones tradicionales para su detección se han basado principalmente en métodos de cultivo, los que permitirían el crecimiento de hongos no necesariamente de origen marino. El presente trabajo resume resultados obtenidos con diferentes aproximaciones metodológicas sobre la distribución, diversidad y ecología de hongos, que respaldan su presencia como componentes activos de la comunidad microbiana del océano costero. Así, resultados de la distribución espacial y temporal de la biomasa y diversidad fúngica en la columna de agua del ecosistema de surgencia de Chile central son consistentes con cambios en las condiciones fisicoquímicas, patrones de distribución de otros microorganismos y la actividad heterotrófica. También se muestra una estrecha relación simbiótica de hongos con diatomeas marinas, que evidencia su potencial efecto sobre la sucesión del fitoplancton en ecosistemas altamente productivos. Patrones de diversidad beta en fiordos y aguas oceánicas de la Patagonia chilena, sugieren también la presencia de comunidades de hongos características de las masas de agua predominantes y una relación con variables biogeoquímicas consistente con un condición de microorganismos activos. Finalmente, la presencia de abundantes taxa desconocidos sugiere un origen marino para una variedad de nuevos componentes fúngicos en el océano costero.

Financiamiento parcial de COPAS Sur-Austral CONICYT PIA APOYO CCTE AFB170006

66 Dormancy and spore formers: Investigating non-standard models

Latencia y esporulación: Investigando nuevos modelos

Mathilda Hayoz1, Ilona Palmieri1, Teddy Monrouzeau1, Matthieu Berge2, Patrick Viollier2, Thorsten Blum3,4, Benoit Zuber5, Marek Kaminek5, Adolfo Odriozola5, Pilar Junier1. (1) Laboratory of Microbiology, Institute of Biology, University of Neuchâtel (2) Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva (3) Center for Cellular Imaging and NanoAnalytics (C-CINA), Biozentrum, University of Basel (4) Biology and Chemistry, Laboratory of Biomolecular Research, Paul Scherrer Institute (5) Microscopic Anatomy and Structural Biology, Institute of Anatomy, Faculty of Medicine, University of Bern

Natural microbial communities have to cope with unstable environmental conditions, which are suboptimal for metabolic activity. There are several strategies to favour survival, among them the production of resistant bacterial spores. In order to investigate sporulation and to characterize the structure and resistance of spores, the reliable production of spores is necessary. However, information concerning triggers of sporulation is still incomplete. One of the few elements knowing to trigger sporulation is manganese, which is often used to stimulate sporulation in the genus Bacillus. Nevertheless, little is known about the effect of this chemical on sporulation, and more generally in microbial morphogenesis. We are investigating the effect of Mn on the morphogenesis of a species from the Firmicute genus Kurthia. This genus was previously considered as asporogenic, but we have unveiled the formation of spores by a putative mechanism involving a modification of the cell envelope in the absence of engulfment, in contrast to the classical endosporulation. Accordingly, we are investigating the impact of manganese on this non-standard spore- former model. Cells of Kurthia under the direct influence of MnSO4 applied as drop on nutrient 3% agar changed in morphology. However, the formation of phase-bright bodies was not observed. This is in contrast to Bacillus, in which sporulation is clearly induced by Mn. The two Kurthia morphotypes are currently under characterization by transcriptomics, Cryo electron microscopy, and other methods such as atomic force microscopy and RAMAN spectroscopy to determine the role of Mn in morphogenesis and sporulation in Kurthia.

Swiss National Science Foundation (SNSF)

67 Investigations into the community structure of potential Iron oxidizing anaerobic bacteria in the oxygen minimum Zone in the north of Chile

Investigación de la estructura comunitaria de potenciales bacterias anaeróbicas oxidantes del hierro en la zona de mínimo oxígeno del norte de Chile

Maija Heller1, Montserrat Aldunate2, Salvador Ramirez-Flandes2, Osvaldo Ulloa 2. (1) Facultad de Ciencias del Mar y Geografía, Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso (2) Departamento de Oceanografía, Universidad de Concepción (Sponsored by Pontificia Universidad Católica De Valparaíso)

Iron (Fe) is a limiting nutrient in many regions of the open ocean and can also play a key role in controlling primary productivity in Eastern Boundary Upwelling Systems (EBUS). In EBUS regions, where intense oxygen minimum zones (OMZs) contact the continental shelf, significant inputs of Fe as Fe(II) from reducing sediments can occur. How much Fe mixes into the photic zone depends on physical mixing and the kinetics of redox and complexation processes. In this presentation we combine observations from previous work in the Eastern Tropical South Pacific OMZ; (i) in situoxidation rates (Croot et al., 2019)derived from fitting Fe(II) distributions in the water column with a 1D model for Fe(II) release from sediments and (ii) particulate iron speciation in the same region (Heller et al., 2017). Both works suggest that nitrate-dependent anaerobic Fe(II) oxidizing (NDFO) bacteria are the main oxidizers for Fe(II) in OMZ waters. However at the secondary nitrite maxima (SNM), there is often a significant Fe(II) signal indicating reduction processes dominate over oxidation. At the SNM abiotic NO2− or biotic-mediated processes may also be important for Fe(II) oxidation. Current and future work is aimed linking water column distributions of nutrients and dissolved Fe(II) with metagenomic and metatrancriptomic data of microbial communities with focus in the SNM of the OMZ, in the north of Chile, to identify likely NDFO bacterial groups and their role in iron cycling in OMZs.

Pontificia Universidad Católica de Valparaíso

68 Thermophilic and thermotolerant microorganisms cohabit in extreme geochemical gradients

Microorganismos termófilos y termotolerantes cohabitan en gradientes geoquimicos extremos

Martha Brigitte Hengst9,1, Johanna Cortés9,1, Vilma Pérez2, Wade Jeffrey3, Verónica Molina5,4, Erika Neat3, Valeska Alcayaga9,1, Sara Cuadros6, Yohana Eissler7, Cristina Dorador9,8. (1) Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte (2) Australian Center for Ancient Dna (Acad), Australia, University of Adelaide (3) Center for Environmental Diagnostic & Bioremediation, University of West Florida (4) Departamento de Biologia, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha (5) Observatorio de Ecologia Microbiana (6) Escuela de Ingenieria en Biotecnologia, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule (7) Instituto de Química y Bioquímica, Facultad de Ciencias, Universidad de Valparaiso (8) Departamento de Biotecnologia, Laboratorio de Complejidad Microbiana y Ecologia Funcional, Universidad de Antofagasta (9) Cebib

Los ambientes termales de gran altura en los Andes Centrales, se ubican por sobre los 3.000 m s.n.m., y constituyen laboratorios naturales dominados por microorganismos. Estos ecosistemas han sido estudiados para determinar su potencial en la obtención de energía geotérmica; sin embargo, poco se conoce sobre la diversidad y mecanismos de adaptación que han evolucionado los organismos para proliferar bajo diversas presiones ambientales. El objetivo de este trabajo fue caracterizar la diversidad microbiana del sistema hidrotermal de Lirima (4.200 m s.n.m), determinar su rol en el ciclo del azufre y establecer los potenciales mecanismos de adaptación a gradientes geoquímicos mediante técnicas moleculares y analíticas. Los resultados demuestran que distintas pozas termales (P42, P53A,B,C y P72) son colonizadas por microorganismos termófilos anaeróbicos, micro-aerofílicos y algunos aeróbicos, y que participan en el ciclo del S como sulfato reductores y oxidantes de compuestos reducidos de azufre evidenciado mediante el gen aprAB (Illumina, itag). En pozas de menor temperatura (42°C y 53°C) Bacteria es dominado por Chloroflexi (33,36% y 58,63%, respectivamente), y a mayor temperatura por Firmicutes (49.97%, 72°C). Por otra parte, para Archaea se determinaron principalmente grupos termófilos anaerobios como Crenarchaeota, Diapherotrites, Nanoarchaeota, Hadesarchaeota, Thaumarchaeota, and Euryarchaeota. El análisis metagenómico demuestra la presencia de diversos mecanismos de adaptación en respuesta a un gradiente de temperatura (42 a 72°C) inverso al gradiente de pH (7,8 a 5,2), que aparecen como los factores mas relevantes en la estructura comunitaria; en los cuales están proteínas de estrés térmico, histona-like, formación de esporas, moléculas antioxidantes, entre otros

FONDECYT 1181773; 1171324, PIA CeBiB FB0001

69 Antimicrobial resistant bacteria and horizontal gene transfer in agricultural soils

Resistencia antimicrobiana de bacterias y transferencia horizontal de genes en suelos agrícolas

Marcela Hernández1, Dorothee Kinkel2, Marc G. Dumont1, Charles W. Keevil 1. (1) University of Southampton, United Kingdom (2) University of Bonn, Germany

Agricultural soils are a potential source of antimicrobial resistance (AMR) due to the ingress of antimicrobials into soil. In this study, we identified antimicrobial resistant bacteria and investigated if horizontal gene transfer (HGT) occurs between pathogens within soil microbiomes in British agricultural soils.Soil samples were incubated with cefotaxime, meropenem, ciprofloxacin and trimethoprim in 18O-water. After incubation, the DNA was extracted and subjected to isopycnic centrifugation to identify microorganisms enriched with 18O. The 16S rRNA gene from the “heavy” and “light” fractions was sequenced using Illumina MiSeq. Results show that members of the phyla Acidobacteria are highly abundant after two days of incubations. We also observe the presence of Proteobacteria including Stenotrophomonas after four days of incubations. To investigate HGT in soils, microcosms were established using three different agricultural soils, and inoculated with the donors Klebsiella pneumoniae NCTC 13443 and Escherichia coli NCTC 13441 together with a recipient Escherichia coli J53 and incubated at room temperature. The results showed that bacteria could be recovered on selective agar plates from the soil after 48 h, indicating that both the donors and recipient can survive in the soil. HGT of blaCTX-M- 15 from K. pneumoniae NCTC 13443 and E. coli NCTC 13441 to E. coli J53 occurred in soil. The results indicate that both native bacteria as well as potential clinical pathogens are present in this agricultural soil. Additionally, this study confirms that HGT can occur in the soil and there is the potential for dissemination of AMR genes in agricultural soils.

NERC (The Natural Environment Research Council) grant NE/N02026X/1, and NAMRIP (Network on Antimicrobial Resistance and Infection Prevention), University of Southampton, United Kingdom.

70 Composition, function and co-occurrence networks of bacterial communities present in the rhizospheres, endospheres and phyllospheres of Antarctic vascular plants

Composición, función y redes de co-ocurrencia de comunidades bacterianas presentes en las rizosferas, endosferas y filosferas de plantas vasculares antártica

Qian Zhang1, Jacquelinne Acuña2, Nitza Inostroza2, Paola Duran2, Maria De La Luz Mora3, Michael Sadowsky1, Milko Alberto Jorquera3. (1) The BioTechnology Institute, University of Minnesota (2) Scientific and Technological Bioresource Nucleus , Universidad de La Frontera (3) Departamento de Ciencias Químicas y Recursos Naturales, Ingenieria y Ciencias, Universidad de La Frontera

Studies have reported the success colonization of free-ice lands by two vascular plants (Deschampsia antarctica and Colobanthus quitensis) in Antarctic peninsula. Despite the known importance of microbiota on growth and tolerance of plants the role of plant-associated microbiota on colonization of free-ice lands remain unknown. Here, we explored the composition, predicted function and co-occurrence networks of plant-associated microbial communities in rhizosphere, endosphere and phyllosphere of D. antarctica and C. quitensis, by using high-throughput DNA sequencing. Our study showed higher number of OTUs, diversity and richness in the rhizosphere compared with endosphere and phyllosphere. Despite that taxonomic assignments showed higher relative abundances of Proteobacteria (35.7- 75.4%), Bacteroidetes (9.3-30.9%) and Actinobacteria (4.8-26.1%) in the three niches, principal coordinate analysis revealed a significant differentiation among their bacterial communities. Our results also showed that 75.8-83.2% of OTUs were not shared and they were exclusively found in each plant niche. In relation to the functions, the major functional groups were attributed to chemoheterotrophy (30.5-44.3%), aerobic chemoheterotrophy (25.8-36.3%), fermentation (3.4-9.7%) and nitrate reduction (1.8-5.2%). Respect to microbial indicators,Pseudomonas was observed as the most abundant genus in the three plant niches while Clavibacter, Novosphingobium and Dactylosporangium were identified as the best taxonomic indicators in endosphere, phyllosphere and rhizosphere, respectively. Finally, the co-occurrence networks analysis identified 5 (e.g., Microbacteriaceae, Pseudomonaceae, Lactobacillaceae and Corynebacteriaceae), 23 (e.g., Chitinophagaceae and Sphingomonadaceae) and 7 (e.g., Rhodospirillaceae) keystone taxa in endosphere, phyllosphere and rhizosphere, respectively. To our knowledge, this is the first study revealing the microbiota among niches of Antarctic plants.

This study was funded by INACH (RT_02_16 and RT_06_17) and FONDECYT (1160302, 11160112 and 1181050).

71 Uncovering the microbial life from the deep-sea sediments of the Southern Gulf of Mexico, after four years of oceanographic campaigns

Descubriendo la vida microbiana en los sedimentos de las aguas profundas del sur del golfo de México, después de cuatro años de campañas oceanográficas

M. Asunción Lago-Lestón1, Haydee López 1, Clara Barcelos1, Jennyfers Chong-Robles1, Dante Magdaleno1, Karla Sidón1, Briceida Covarrubias1. (1) Centro de Investigación Científica y Educación Superior de Ensenada (CICESE)

The Gulf of Mexico (GoM) is an ocean basin characterized by both shallow and deep-water areas, which can reach depths up to 4,000 m. Some studies describing its biological diversity have been done but very few involve microbial communities from the sediments, and even less from the deepest areas. To establish a baseline and to shed some light into the microbial diversity inhabiting the southern GoM, sediment samples were collected over different years since 2015, as part of a sampling effort doing by the CIGoM consortium. Samples were taken at different depths, from 550 to more than 3500 m. DNA was extracted from different sections of the sediment column, 16S rRNA gene was amplified and sequenced on MiSeq (Illumina) platform and data was analyzed with several bioinformatic programs including QIIME. Our results show an unusual archaeal abundance, reaching up to 40% of the total prokaryotes community, in particular, those from the deepest locations. This abundance seems to be correlated with depth since it is increased from shallow to deeper zone, but it is stable at the abyssal plain (1500 to 3500m). Besides, it was observed a strong shift on the microbial assemblages along the sediment core. The archaeal diversity was higher and distinct than those from the upper part of the core and, the bacterial abundances changed. Lokiarchaea replaced Thaumarchaea and represented 20% of the total. And in the bacterial group, Planctomycetes and Chloroflexi increased their abundances while Acidobacteria almost disappeared from the bottom of the core (30cm).

Research funded by the National Council of Science and Technology of Mexico - Mexican Ministry of Energy - Hydrocarbon Trust, project 201441. This is a contribution of the Gulf of Mexico Research Consortium (CIGoM)

72 Functional and structural response of methanogenic communities due to temperature increases in lakes of Patagonia and the Sub-Antarctic eco-region of Magallanes (Chile)

Respuesta funcional y estructural de las comunidades metanogénicas frente a aumentos de temperatura en lagos de la Patagonia y de la eco-región Sub-Antártica de Magallanes (Chile)

Céline Lavergne2, Polette Aguilar-Muñoz2, Natalia Calle1, Sebastian Olivares1, Frederic Thalasso3, Maria Soledad Astorga4, Armando Sepulveda-Jauregui4, Karla Martinez-Cruz4, Laure Gandois5, Roman Teisserenc5, Rolando Chamy2, Maialen Barret5, Léa Cabrol6. (1) Departamento de Química, Universidad Técnica Federico Santa María (2) Escuela Ingeniería Bioquímica, Laboratorio de Biotecnología Ambiental, Pontificia Universidad Católica Valparaíso (3) Departamento de Biotecnología y Bioingeniería, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (Cinvestav-IPN) (4) Departamento de Ciencias y Recursos Naturales, Universidad de Magallanes (5) UPS, INP, EcoLab, ENSAT, CNRS, EcoLab, Laboratoire d´écologie fonctionnelle et environnement, Université de Toulouse (6) CNRS-IRD, Mediterranean Institute of Oceanography (MIO-UM 110), Aix-Marseille Université/Univ Toulon

Due to organic matter accumulation and anaerobic microbial processes, wetlands are known to contribute greatly to global warming through methane emissions. Polar wetlands are more strongly affected by climate change. This could lead to a positive feedback on regional methane budget and global warming through modifications of microbial community structure and methanogenic activity. Yet, the outcome of temperature increase on methanogenic communities and processes in Sub-Antarctic wetlands has been more investigated than Sub-Arctic counterparts. We demonstrated that temperature increase stimulated methanogenic activity in microcosms from 5 Sub-Antarctic lake sediments (from Patagonia to Cape Horn, Chile) incubated at different temperatures (5-10-15-20°C). At low (close to in-situ) temperatures (5-10ºC), the acetoclastic pathway contributed predominantly (92.5%) to methane production, in all samples. At higher temperatures, the hydrogenotrophic contribution increased, up to 71.8% in the Patagonia samples. The cumulated produced methane was significantly correlated to the mcrA gene quantity, revealing an enrichment of methanogens with favorable conditions. The methanogenic archaeal community (Illumina-MiSeq 16S rRNA gene sequencing) was specialized according to the spiked substrate with a dominance of Methanobacterium in hydrogenotrophic experiments (representing up to 0.4% of total community) and Methanosarcina in acetoclastic experiments (representing up to 0.07% of total community). In unamended microcosms, the in-situ diversity was highly conserved. Peatland lakes from Cape Horn exhibited higher methanogenic potential and strongest temperature sensitivity and the investigation of their response to global changes deserves more interest. Especially, from the whole microbial community, we are currently identifying the keystone taxa, exhibiting a critical response to temperature increase.

ERANET-LAC Methabase ELAC 2014/DCC092, ECOS C16B03, FONDECYT Postdoc nº3180374 MEMARC

73 Antarctica as a natural laboratory for bioprospecting microbial resources in the context of the global antibiotic resistance crisis

Antártica: un laboratorio natural para la bioprospección de recursos microbianos en el contexto de la crisis global de resistencia a antibióticos

Andrés Marcoleta1, Macarena Varas1, José Costa1, Johanna Rojas1, Sofía Tapia1, Daniel Acuña1, Rosalba Lagos1. (1) Laboratorio de Biología Estructural y Molecular BEM, Departamento de Biología, Facultad de Ciencias, Universidad de Chile

Nowadays, the antibiotic resistance crisis is the most significant concern for public health worldwide. The increasing detection of bacterial pathogens resistant to all the available antibiotics, along with the lack of new drugs under clinical development are leading to incurable infections, taking humanity back to the pre-antibiotic era when infectious diseases were the main cause of mortality. Intensive research is required not only to obtain new antibiotics but also to understand how resistance arise and disseminate, as well as the molecular mechanisms behind it. In this context, we exploited the unique microbial resources found in Antarctica, as well as the isolation and remoteness of this territory, for the prospection of novel bacterial strains producing antimicrobial compounds, and for evaluating the influence of human activities on the presence of bacteria resistant to antibiotics. We generated a collection of ~200 strains isolated from pristine areas and human settlements in the Antarctic Peninsula, testing their antimicrobial resistance and antimicrobial activity. Strikingly, a comparable number of strains resistant to up to 10 different antibiotics classes was observed both in pristine and humanized areas. Genomic analysis of the top multiresistant strains indicated the presence of novel resistance mechanisms currently under study. Additionally, valuable strains producing antimicrobial compounds active against Pseudomonas and multiresistant Klebsiella pneumoniae were identified. Grant INACH RT-51_16 (A Marcoleta)

74 Seasonal changes in bacterial structure in a tropical estuary strongly influenced by riverine discharges

Variación estacional de la comunidad bacteriana en un estuario tropical fuertemente influenciado por la descarga riverina

Carolina Marín-Vindas1,2, Marta Sebastián1,3, Clara Ruiz-González1, Vanessa Balagué1, Luis Vega-Corrales2, Josep M Gasol1. (1) Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Catalunya, Spain (2) Estación de Biología Marina, Escuela de Ciencias Biológicas, Universidad Nacional, Costa Rica (3) Instituto de Oceanografía y Cambio Global, Universidad de Las Palmas de Gran Canaria, Gran Canaria, Spain

Estuaries are among the most productive ecosystems in the world. They are considered as changing environments because the interaction of freshwater and seawater leads to the formation of specific conditions strongly influenced by a combination of physical, chemical and biological drivers. Nicoya´s gulf is a tropical estuary located in the Pacific coast of Costa Rica and is characterized by high riverine discharges during the rainy season. Here, we sampled seawater from different sites of the gulf during the dry and rainy season and we analyzed the bacterial diversity through illumina amplicon sequencing (16S rRNA gene) in order to determine the bacterial community structure as well as the horizontal connectivity during each season. Our results show a pronounced difference in bacterial community structure between seasons and sampling sites as well as different patterns of horizontal connectivity. During the dry season, changes in the community structure occurred gradually following the movements of currents within the gulf, while in the rainy season the community structure was highly influenced by the riverine discharge. This study sheds light on the structure of bacterial communities in a highly dynamic tropical estuarine system.

75 Yeasts as plant growth promoter for rice (Oryza sativa, L.)

Levaduras promotoras de crecimiento en plantas de arroz (Oryza sativa, L.)

Kerly Martinez1, Jerri Édson Zilli2. (1) Ciencias del Suelo, Agronomia, Universidade federal Rural do Rio de Janeiro (2) Embrapa Agrobiologia

Las levaduras son hongos unicelulares que se pueden encontrar de forma natural en la rizosfera y la filósfera de las plantas. Algunas especies tienen la capacidad de participar en varios procesos biotecnológicos importantes, tales como: control biológico de hongos por su capacidad para producir toxinas killer, producción de sideróforos y otros compuestos conocidos como promotores del crecimiento en las plantas. Este trabajo tuvo como objetivo evaluar la promoción del crecimiento en plantas por levaduras de ambientes naturales. En invernadero se realizaron pruebas de germinación sobre semillas de arroz. El experimento se realizó en un diseño completamente al azar, con 6 repeticiones, 2 tratamientos (inoculados y no inoculadas) y 11 levaduras fueron evaluadas. Las levaduras se cultivaron en medio líquido YMA a 120 rpm durante 2 días. las semillas se distribuyeron en macetas Leonard que contenían arena y vermiculita 1: 1. Después de la germinación de las semillas, las plántulas se inocularon con 1000 μl de solución de levaduras, el control no se inoculó. El crecimiento fue evaluado 30 días después de la inoculación. El análises de la parte aérea, diámetro, raíz y brote mostró que 6 levaduras (Cryptococcus heveanensis, Yamadazyma riverae, Spathaspora suhii, Cyberlindnera xylosilytica, Torulaspora sp., Candida sp.) Proporcionaron un mayor aumento en la parte aérea, 25% más de diámetro y 35% más de biomasa fresca total. Los resultados indicaron que estas levaduras realizan mecanismos que proporcionan un mayor crecimiento de la planta. CNPq, Embrapa, UFRRJ.

76 Microbial gradients in carbonate tufas from Big Soda Lake, Nevada

Gradientes microbianos en tufas del lago alkalino Big Soda Lake, Nevada

Fernando Medina Ferrer1, Michael Rosen2, Virginia Russell3, Jayme Feyhl-Buska4, Fredrik Sønderholm5, Sean Loyd6, Russell Shapiro7, Blake Stamps8, Victoria Petryshyn9, Jake Bailey1, Hope Johnson10, John Spear8, Frank Corsetti4. (1) Earth Sciences, Science and Engineering , University of Minnesota, Twin Cities (2) US Geological Survey, Carson City, NV, United States (3) Department of Plant and Microbial Biology, University of California, Berkeley (4) Department of Earth Sciences, University of Southern California (5) Department of Geosciences and Natural Resource Management, University of Copenhagen (6) Department of Geological Sciences, California State University Fullerton (7) California State University Chico (8) Department of Civil and Environmental Engineering, Colorado School of Mines (9) Environmental Studies Program, University of Southern California (10) Department of Biological Science, California State University Fullerton

Big Soda Lake, a groundwater-fed, alkaline and stratified saline lake near Fallon, Nevada, host modern columnar tufas (porous, non-marine carbonates) containing diverse biological communities. Here, we show that microbial communities inhabiting subaqueous and potentially actively-accreting tufas exhibit a gradient in community composition across the carbonate structure. Correspondence analysis of microbial communities from the surface lake water through the interior of the tufa is characterized by a horseshoe effect using Euclidean, chi-squared, Bray-Curtis and unweighted UniFrac distance metrics, an effect extensively observed in environmental gradients and potentially derived from the saturation of the distance test. Tufas also show a geochemical gradient in their carbonate isotopic composition that likely originated as a consequence of the water gradient formed when freshwater upwells into the saline lake. As tufas get larger and thicker with carbonate precipitation over time, the geochemical gradient from fresh groundwater to saline lake water becomes wider. The growing gradient indicates that the tufa microbial communities likely change over time due to changing salinity, implying that the microbial communities are not static during the tufa growth. The horseshoe pattern may therefore represent niche differentiation of taxonomic units with respect to physicochemical gradients originated at Big Soda Lake, providing a wider range to host a stratified, diverse microbial community, where tufas serve as geochemical vessels of microbial diversity.

Funded by the Agouron Institute, the Center for the Dark Energy Biosphere Investigations (C-DEBI), theUSC Wrigley Institute and NASA award NNX14AK20G to JVB. FMF was supported by Fulbright #15150776 and CONICYT folio-72160214.

77 Diversity of cultivable and non-cultivable air microbiota at peninsula fildes (maritime antarctica)

Diversidad de la microbiota cultivable y no cultivable del aire en la peninsula fildes (antartida maritima)

Rodolfo Javier Menes1, Andrea Fraga1, Diego Roldan1. (1) Microbiologia-LEMM, Facultad de Química y Unidad Asociada de Facultad de Ciencias, Universidad de la República. Uruguay.

La atmósfera tiene un rol fundamental en el transporte de microorganismos por todo el planeta. Es un ambiente extremo en el cual los microorganismos están expuestos a baja temperatura y elevada radiación. Muchos de esos microorganismos pueden mantener la viabilidad durante su permanencia en el aire, debido a mecanismos moleculares de resistencia y adaptación, e incluso se ha postulado que pueden estar metabólicamente activos y multiplicarse. Dado que su presencia influye activamente en la química de la atmósfera y en procesos fisicoquímicos como la formación de nubes y nucleación del hielo, es de gran interés estudiar su biodiversidad. En el presente trabajo se estudió la microbiota total y la cultivable por medio de muestreos de aire por medio de un muestreador por impacto en placas con R2A agar y en medio líquido. Se tomaron 16 muestras a 1,5 m de altura en dos años consecutivos y en verano, en la península Fildes (isla Rey Jorge, Antártida marítima). La diversidad de la microbiota total se analizó por secuenciación masiva (Illumina MiSeq) y reveló que más del 90% de las secuencias pertenecen a los filos Proteobacteria, Firmicutes, Actinobacteria y Bacteroidetes. El recuento de microorganismos viables resultó muy variable, con valores de menos de 1 a 1000 ufc/m3. Se obtuvieron más de 100 aislamientos cuya identificación por secuenciación del gen ARNr 16S determinó que pertenecen a los filos Proteobacteria (géneros: Acinetobacter, Brevundimonas, Pseudomonas, Psychrobacter, Stenotrophomonas, Variovorax), Actinobacteria (géneros: Arthrobacter, Glaciihabitans, Leifsonia, Microbacterium, Pseudarthrobacter, Salinibacterium, Rathayibacter, Rhodococcus) y Bacteroidetes (géneros: Flavobacterium, Hymenobacter, Pedobacter).

78 Metagenomic analysis of microbial mats from McMurdo Dry Valley´s

Análisis metagenómico de tapetes microbianos de McMurdo Dry Valley´s

Ricardo Augusto Mercado1, Luisa Falcón1. (1) Laboratorio de Ecología Bacteriana, UNAM

La Antártica se caracteriza por su aislamiento geográfico y climático. Es uno de los ambientes terrestres más extremos para ser habitado por organismos vivos. “McMurdo Dry Valleys” (MDV) es la región libre de hielo más grande en el continente, localizada en el margen costero entre los ~77°-79°S y ~160°-164°E, en Victoria Land, Antártica Occidental. Es un área de especial importancia ambiental debido a las características únicas derivadas del clima extremo, topografía y posición geográfica, por lo que se considera un desierto polar extremo. La biota dominante en este sitio inhóspito son las comunidades microbianas, su actividad biológica incrementa y se hace visible en el verano austral, cuando se deshielan los glaciares y forman corrientes efímeras por ~ 10 semanas, siendo la única fuente principal de agua líquida en MDV. Las más visibles, son los tapetes microbianos de corrientes efímeras, varios estudios taxonómicos basados en 16S ARN sugieren que son comunidades diversas en MDV. En este estudio presentamos resultados sobre el potencial taxonómico (abundancia y riqueza), el potencial funcional (rutas metabólicas relacionadas con el ciclaje de carbono, nitrógeno, azufre), su relación y el aporte de los taxa raros o menos abundantes al potencial funcional, a partir del análisis metagenómico (metagenomic shotgun sequencing) de cinco metagenomas de tapetes microbianos colectados en el verano austral de 2015 en tres localidades de MDV.

79 Bacteria communities and connectivity in proglacial aquatic environments from Mount Tronador system (Patagonia; Argentina)

Comunidades bacterianas y conectividad en ambientes proglaciares del Monte Tronador (Patagonia, Argentina)

Beatriz Estela Modenutti1, Marcela Bastidas Navarro1, Nicolás Martyniuk1, Sebastián Marquez1, Esteban Balseiro1. (1) INIBIOMA, Universidad Nacional del Comahue-CONICET

Aquatic ecosystems in the North Patagonia are facing changes as a result of glacial recession due to global warming. Here, we studied different bacterial communities and connectivity in different aquatic environments of the Tronador Mountain system corresponding to both, Atlantic and Pacific watersheds. We sampled streams, a newly formed lake and two proglacial lakes (upper and lower strata) that receives the input of glacial clays. In addition, we studied two lakes in the area that, at the present, are not connected with glaciers. We determined nutrient concentrations, bacteria abundances, and bacteria community composition using next-generation sequencing of the 16S rRNA gene. Results showed that each environment had distinctive microbial assemblages and only 171 phylotypes were shared by the different studied environment. The highest species richness and the highest number of exclusive phylotypes, were observed in the newly formed lake Ventisquero Negro. However, several taxa (314) present in this proglacial lake, still in contact with the glacier, remain in downstream communities of the deep Lake Mascardi. The obtained results imply that the rapid changes that occur in proglacial lakes associated with climate warming will affect downstream microbial community structure throughout all spatially connected habitats.

PICT 2015-0418 y PICT 2017-1940

80 Temporal changes of microbial communities associated with oxygen minimum zone (OMZ) waters at the Oceanographic Station off Valparaíso (STOV at 32ºS, Chile)

Variación temporal de comunidades microbianas asociadas a la zona de minima de oxígeno (OMZ) en la Serie de Tiempo Oceanográfica de Valparaiso (STOV a los 32ºS, Chile)

Veronica Andrea Molina1, Marcela Cornejo2, Alejandro Murillo3, Hermann Peña1, Melline Fontes-Noronha1, Katterinne N. Mendez4, Eduardo Castro-Nallar4. (1) Departamento de Biologia, Facultad de Ciencias Naturales y Exactas, Universidad De Playa Ancha De Ciencias De La Educación (2) Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso (3) Structural and Computational Biology Unit, EMBL - Heidelberg, Germany (4) Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello

The Eastern South Pacific OMZ has been described as a prominent oceanographic feature characterized by diverse and active microorganisms contributing to sulfur and nitrogen recycling. Herein, present and active microbial community were studied using MiSeq-itag-16S rDNA and RNA (V4, Bacteria+Archaea) at STOV 2016 and 2018 at 25, 100, 150, 200, 300, 400 m depth (12 months from contrasting seasons). Results showed an OMZ with a variable intensity (0–1.5 ml O2 L-1) situated at 75-400 m depth related with intense nitrogen cycling evidenced by nitrogen deficiency (N* -33.2 to -11.09). Alpha diversity analyses showed a richer (ES) and diverse (H`) community at RNA compared to DNA (max 223/210; 3.9/3.6). STOV core community was associated to Gammaproteobacteria (SAR86 and Thiomicrospirales), Alphaproteobacteria (SAR11), Bacteroidetes (Flavobacteraceae) and Thaumarchaeota. This later, was associated with the aerobic ammonium oxidizing archaea (order Nitrosopumilales). Besides, other key functional microbes related with nitrogen and sulfur cycles were detected in low number (<0.4% of the sequences), i.e., anammox bacteria (anaerobic ammonium oxidizer, which oxidize ammonium with nitrite producing molecular nitrogen), facultative anaerobic sulfur oxidizing bacteria (oxidize sulfur with nitrate) and Nitrospina (nitrite oxidizer). Preliminary metagenomic analyses from this OMZ supports the relevance of nitrifying archaea and potential metabolic core OMZ functional groups associated with oxygen variability, also supported by the quantification of specific nitrifying groups (qPCR- ammonia monooxygenase subunit A and 16S rRNA, of Nitrosupumilus maritimus and Nitrospina spp). In total, our results suggest a key core OMZ microbial community in the study area as drivers of nitrogen recycling.

Fondecyt 1171324

81 Transcriptional variations of PAH degrading strain Burkholderia sp. Bk in co-culture with another PAH degrading strain

Variaciones transcripcionales de la cepa degradadora de PAH Burkholderia sp. Bk en co-cultivo con otra cepa degradadora

Esteban Nieto1, Marianela Macchi 1, Irma S Morelli2, Bibiana M Coppotelli1. (1) CINDEFI (UNLP-CONICET), Universidad Nacional de la Plata. Facultad de Ciencias Exactas (2) Comisión de Investigaciones Científicas de la Provincia de Buenos Aires- CINDEFI, Universidad Nacional de La Plata, Facultad de Ciencias Exactas

Las interacciones interespecíficas son fundamentales en consorcios microbianos responsables de procesos degradativos. En trabajos anteriores en co-cultivo se encontraron evidencias que la cepa degradadora Sphingobium sp. AM sería la responsable del ataque inicial al fenantreno. Este trabajo tuvo como objetivo estudiar las variaciones en la expresión de genes catabólicos de la degradación de fenantreno en Burkholderia sp. Bk. cuando conforma un co-cultivo con AM, ambas cepas fueron aisladas de un consorcio natural degradador de PAH. Se preparó el co-cultivo AM-Bk (proporción 65:35) en MML con 200 mg/L del hidrocarburo. Se utilizaron primers, diseñados a partir del genoma de Bk, dirigidos a genes que codifican enzimas dioxigenasa de la vía alta (Naph y Biph) y de la vía baja de degradación (Tol, Sal y Cat) (RT-qPCR) (2, 8, 24 y 72 hs). Los datos se analizaron mediante el método de ΔΔCt (gen de referencia: gen ribosomal 16S). Como condición de referencia se utilizó las 2 hs de incubación. En el análisis por RT-qPCR, el cultivo mixto mostró sub-expresión de los genes Naph y Biph desde las 24 hs de incubación y sobre- expresión a las 72 hs de incubación de los genes Sal y Cat, con respecto al cultivo puro. Adicionalmente en el co- cultivo a las 72 hs hubo mayor expresión de todos los genes de la vía baja estudiados, con respecto a las 8 hs. Los resultados obtenidos confirman la complementación de ambas cepas en la degradación de fenantreno, demostrando que Bk interviene principalmente en la degradación de compuestos intermediarios.

82 Niche Differentiation among Annually Recurrent Coastal Marine Group II Euryarchaeota

Diferenciación de nichos entre poblaciones de Euryarchaeota costeras, recurrentes y anuales del Grupo Marino II

Luis H. Orellana1, T. Ben Francis1, Karen Krüger1, Hanno Teeling1, Marie-Caroline Müller1, Bernhard Fuchs1, Konstantinos Konstantinidis2, Rudolf Amann1. (1) Max Planck Institute for Marine Microbiology (2) Georgia Institute of Technology

Since the discovery of archaeoplankton in 1992, the euryarchaeotal Marine Group II (MGII) remains uncultured and less understood than other planktonic archaea. We characterized the seasonal dynamics of MGII populations in the southern North Sea on a genomic and microscopic level over the course of four years. We recovered 34 high- quality metagenome-assembled genomes (MAGs) of MGIIa and MGIIb that corroborated proteorhodopsin-based photoheterotrophic lifestyles. However, MGIIa and MGIIb MAG genome sizes differed considerably (~1.9 vs. ~1.4 Mbp), as did their transporter, peptidase, flagella and sulfate assimilation gene repertoires. MGIIb populations were characteristic of winter samples, whereas MGIIa accounted for up to 23% of the community at the beginning of summer. Both clades consisted of annually recurring, discrete populations with low intra-population sequence diversity. Oligotyping of filtered cell-size fractions and microscopy both suggested that MGII cells were predominantly free-living. Cells were coccoid and ~0.7 µm in diameter, likely resulting in grazing avoidance. Based on multiple lines of evidence, we propose distinct niche adaptations of MGIIa and MGIIb Euryarchaeota populations that are characteristic of summer and winter conditions in the coastal North Sea.

The study was funded by the Max Planck Society.

83 Evaluating neutral- and niche-based mechanisms shaping bacterial community composition along a large environmental freshwater-marine gradient

Evaluación de los mecanismos que modulan la estructura comunitaria del bacterioplancton en un amplio gradiente ambiental: rol de procesos neutrales y basados en nicho

Claudia Piccini1, Angel Segura2, Carla Kruk3, Eliana Nervi1, Alvaro González-Revello4, Florencia Bertoglio1, José Sotelo- Silveira4. (1) Departamento de Microbiología, Ministerio de Educación y Cultura, Instituto de Investigaciones Biológicas Clemente Estable (2) Modelización y Análisis de Recursos Naturales (MAREN), Centro Universitario Regional Este, Universidad de la República (3) Ecología Funcional de Sistemas Acuáticos, Centro Universitario Regional Este, Universidad de la República (4) Departamento de Genómica, Ministerio de Educación y Cultura, Instituto de Investigaciones Biológicas Clemente Estable

Analyzing community composition across large spatial scales provide insight into the mechanisms shaping biodiversity. Two fundamental aspects of community organization are species richness and abundance. A third component is the change in species composition in space and time. Here, we describe the bacterial community structure along an environmental gradient from Uruguay river to the outer zone of the Rio de la Plata estuary (~800 km), a large, subtropical ecosystem in South America. We sampled six locations along this gradient and analyzed bacterioplankton community composition by 16S rDNA sequencing, defining operative taxonomical units (OTUs) at 97% sequence similarity. After removing singletons we identified 15705 OTUs, which exhibited a similar abundance among sites, with the highest richness (S~6000) in the river and a constant decrease towards the outer estuary. Species abundance followed a Zipf-Mandelbrot distribution (pseudoR2>0.9), with dominant species (>5%) increasing towards outer estuarine waters, while rare ones were more abundant in riverine freshwaters. According to Sorensen beta-diversity index, observed changes in community structure along the gradient were due to species turnover and not to nestedness, suggesting a niche-based mechanism. This agrees with the left-skewed distribution obtained for the genetic distances between dominant and non-dominant OTUs calculated for each site and contrary to a neutral dynamics. Our results suggest that local environmental filters (mainly salinity) strongly modify microbial community composition by e.g. constraining the viability of bacterial species, particularly that of rare ones. Migration seems to be compensated by strong environmental filters that generate specific niches along this riverine-estuarine continuum.

ANII-LATU ANII-FMV

84 Amplicon-based analysis of soil bacterial communities from 96º/100ºC fumaroles in Deception Island, Antarctica

Análisis de comunidades bacterianas en suelo de fumarolas a 96/100ºC en Isla Decepción, Antártica basado en secuenciación de amplicones

Carolina Paz Quezada1, Sebastián L Márquez2 , Nicolás Bruna1, María De Los Ángeles Cabrera1, Eduardo Castro- Nallar2, José Manuel Pérez-Donoso1. (1) Laboratorio de BioNanotecnología y Microbiología, Facultad de Ciencias Biológicas, Universidad Andrés Bello (2) Laboratorio de Genómica Microbiana, Facultad de Ciencias Biológicas, Universidad Andrés Bello

Deception Island (DI) is an active stratovolcano located in the South Shetland archipelago in Antarctica. It shows diverse geothermal activity, distributed mainly in 3 seashores: Fumarole Bay (FB), Whalers Bay and Pendulum Cove. Fumaroles in FB present unique conditions of extreme temperature (up to 100ºC) that allow the development of hyperthermophiles. In this study we analysed the bacterial community structure of fumaroles based on 16S rRNA gene amplicon sequencing. Data was obtained from the genomic DNA present in soil samples (surface and depth) in fumarole 1 (96ºC), fumarole 2 (100ºC) and 2 sites at 20 m distance from fumarole 1 (one to the inland at 4ºC and other to the seashore side at 2ºC). Bacterial community composition was revealed by assigning taxonomy to the Amplicon Sequence Variants inferred using DADA2 analysis pipeline. Our analyses showed that, at the phylum level, Deinococcus−Thermus and Aquificae are only found in the fumarole samples (Deinococcus−Thermus is only found in depth) and Chloroflexi phylum is found in higher proportions than in non-fumarole samples. The alpha- diversity is significantly lower in fumaroles than in non-fumarole sites. The bacterial compositions are very similar within fumarole samples (except for fumarole 1 depth, where the predominant genus is Hydrogenothermus) and also similar within non-fumarole sites. This is the first report of an amplicon-based analysis of bacteria in fumaroles at 100ºC in DI. Ongoing work consist in isolating hyperthermophiles and other extremophiles from fumarole samples (5 isolates grew at 70ºC in R2A medium), looking for biomolecules with biotechnological applications.

This project is supported by FONDECYT grants 3170718 and INACH RT-25_16.

85 Redox traits characterize the organization of global microbial communities

Los genes asociados a reacciones redox caracterizan a las comunidades microbianas del planeta

Salvador Francisco Ramirez1. (1) Departamento de Oceanografia, Universidad de Concepción

The structure of biological communities is conventionally described as profiles of taxonomic units, whose ecological functions are assumed to be known or, at least, predictable. In environmental microbiology, however, the functions of a majority of microorganisms are unknown and expected to be highly dynamic and collectively redundant, obscuring the link between taxonomic structure and ecosystem functioning. Although genetic trait-based approaches at the community level might overcome this problem, no obvious choice of gene categories can be identified as appropriate descriptive units in a general ecological context. We used 247 microbial metagenomes from 18 biomes to determine which set of genes better characterize the differences among biomes at the global scale. We show that profiles of oxidoreductase genes support the highest biome differentiation when compared with profiles of other categories of enzymes, general protein-coding genes, transporter genes, and taxonomic gene markers. Based on oxidoreductases’ description of microbial communities, the role of energetics in differentiation and particular ecosystem function of different biomes become readily apparent. We also show that taxonomic diversity is decoupled from functional diversity, e.g., grasslands and rhizospheres were the most diverse biomes in oxidoreductases but not in taxonomy. Considering that microbes underpin biogeochemical processes and nutrient recycling through oxidoreductases, this functional diversity should be relevant for a better understanding of the stability and conservation of biomes. Consequently, this approach might help to quantify the impact of environmental stressors on microbial ecosystems in the context of the global-scale biome crisis that our planet currently faces.

This work was supported by the Millennium Science Initiative Grant IC120019 and the Chilean National Commission for Scientific and Technological Research Grant Fondecyt 1161483 and the Center of AppliedEcology and Sustainability [CAPES].

86 Possible microbial life in depths soil in one of the hyper arid core Atacama Desert

Posible vida microbiana en las profundidades de en uno de los núcleos hiperáridos del Desierto de Atacama

Francisco Remonsellez1,2, Alessandra Choque2, Francisco Gómez2, Eduardo Castro-Nallar3, Katterinne Mendez3, Sergio Barahona4, Andrea Jara4, Roland Bol5, Bárbara Fuentes2. (1) Centro de Investigación Tecnológica del Agua en el Desierto-CEITSAZA, Universidad Católica del Norte (2) Ingeniería Química, Universidad Católica Del Norte (3) Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello (4) Laboratorio de Microbiología Aplicada y Extremófilos, Universidad Católica del Norte (5) Institute of Bio- and Geosciences, Forschungszentrum Jülich GmbH

Several studies have demonstrated microbial life in different habitats of the Atacama Desert, which have mainly showed colonization in surficial salt crusts. However, it remains unclear whether the depths of these arid environments support microbial life. The aim of this work is to evaluate possible biotic and abiotic parameters necessary for life, and the bacterial diversity in a hyper arid soil profile (0-340 cm) from Yungay (Atacama Desert) by massive sequencing of the V4 region of the 16S rRNA gene.Sampling was not performed near a rain event.

Our results showed that in the soil profile the P values ranged from 120-890 mg kg-1, but below 50 cm depth the highest values (>470 mg k-1) were found. Moreover, high pH values (average of 8.8) were registered in all soil profile, and highest values of electric conductivity (EC) were found at 30-60 cm (ranged 113-187 mS cm-1). Added to above, moisture content increased with soil depth reaching 20% at 330-340 cm. Preliminary analysis of sequences indicate that Proteobacteria, Actinobacteria and Bacteroidetes phyla showed the highest prevalence in the soil profile. The surface of the soil with high salt concentration was dominated by Proteobateria (31-49%) and Firmicutes (90% at 10-20 cm). The deepest soil was dominated by Proteobacteria, particularly Burkholderiaceae (40% at 330-340 cm), Marinobacteraceae (16% at 320-330 cm), and Sphingomonadaceae (4.7% at 270-280 cm) families. In conclusion, our results suggest that the deep soil could be another suitable life habitat in the hyper arid soils of the Atacama Desert. This work was done as part of a Collaborative Research Center project, CRC1211: ‘Earth-Evolution at the Dry Limit’, funded by German Research Foundation (DFG)

87 Microbial community structure of the subsurface oil sands in Northern Canada

Estructura de la comunidad microbiana de las arenas petrolíferas subterráneas en el norte de Canadá

Christina M. Ridley1, Voordouw Gerrit2. (1) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Biological Sciences, University of Calgary

Northern Canada is home to vast oil reserves estimated at 1.8 trillion barrels; however, unlike conventional light oils, these reserves have been progressively biodegraded over geological time, resulting in an enrichment of high molecular weight hydrocarbons. These recalcitrant hydrocarbons, known as bitumen, make up approximately 20% of the reservoir, with the remainder being sand (~78%) and water (~2%). The unconventional oil from the aptly named oil sands is difficult to extract from the subsurface because the bitumen is solid at room temperature. Despite the significance of the oil sands to the Canadian economy, little scientific research as been conducted on the microbial ecology of this unique environment. Thus, the objectives of this study were to characterize the microbiology along the depth of the subsurface oil sands reservoir using Illumina high-throughput amplicon sequencing. To that end, two samples sets were collected along the depth of the reservoir from ~220-320 meters below the surface (n= 36 samples/set). In an environment that is traditionally considered anoxic, results show a surprising predominance of aerobic Bacteria. Pseudomonas and Acinetobacter were the dominant prokaryotic genera (average relative sequence abundance >15%), while Methanoculleus was the only dominant (>1%) methanogenic Archaea. Fungi from the family Trichocomaceae and the order Hypocreales were the prevailing Eukaryotes. These, and many of the other observed taxa, have potential functions that may be beneficial for oil extraction or bioremediation, including hydrocarbon degradation, biosurfactant production and methanogenesis. Thus, the information revealed in this study could be used as the basis for future biotechnologies.

88 Volatile organic compounds produced by Bacillus paralicheniformis LBEndo1 induce salinity resistance in Arabidopsis thaliana

Los compuestos orgánicos volátiles producidos por Bacillus paralicheniformis LBEndo1 inducen resistencia a salinidad en Arabidopsis thaliana

Jorge Sáenz-Mata1, Ruben Palacio-Rodriguez1, Lourdes Iveth Macias-Rodríguez3, Gisela Muro-Perez2, Jesus Josafath Quezada Rivera1, Jaime Sánchez-Salas2. (1) Laboratorio de Ecología Microbiana, Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango (2) Laboratorio de Botánica, Facultad de Ciencias Biológicas, Universidad Juárez del Estado de Durango (3) Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo

The volatile organic compounds (VOCs) of plant growth promoting rhizobacteria (PGPR) play a significant role in the growth and development of the plants, as well as, it has been found that reduce the negative effects of stress by salinity. This study investigated the effect in vitro of the VOCs emitted by Bacillus paralicheniformis LBEndo1 in Arabidopsis thaliana as stimulated growth, development, and salinity stress tolerance. The rhizobacteria used in this study was isolated from the halophilic grass Distichlis spicata from the Mexican Chihuahuan Desert. Bacillus paralicheniformis LBEndo1 VOCs is able to promote growth and improve the salinity stress tolerance in Arabidopsis under NaCl 50 and 100 mM, increased significantly, the production of proline, chlorophyll and decreasing the amount of Na+in aerial tissues. The volatile organic compounds from halophilic rhizobacteria LBEndo1 on early exposure was sufficient to stimulate long-term effects observed in protection to salinity stress in Arabidopsis. For the identification of VOCs, the solid phase microextraction technique (SPME) was used, being able to identify Acetoin as one of the main compounds related to the promotion of growth and protection against salt stress. In addition, the analysis of the expression of some genes key Na+ transporters was carried out using RT-qPCR in A. thaliana, such as AtHKT1, AtSOS1, AP2, and AtNIT1, which are involved in the response to salt stress.

89 Temporal dynamic of microbial communities in hypertrophic Pampean shallow lakes (Argentina)

Dinámica temporal de la diversidad microbiana en lagunas hipereutróficas pampeanas (Argentina)

María Romina Schiaffino2, Paula Huber1, Mara Inés Sagua2, Carmen Sabio García3, Leonardo Lagomarsino4, Mariana Reissig5. (1) Instituto Nacional de Limnología (INALI, UNL-CONICET), Santa Fe, Argentina. (2) Centro de Investigaciones y transferencia del Noroeste de la Provincia de Buenos Aires (CITNOBA, CONICET- UNNOBA-UNSADA), 6000 Junín, Argentina (3) Instituto de Ecología, Genética y Evolución (IEGEBA, UBA-CONICET), Buenos Aires, Argentina (4) Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM) - Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), CC 164 (B7130IWA) Chascomús, Provincia de Buen (5) GESAP (Grupo de Ecología de Sistemas Acuáticos a escala de Paisaje), Instituto de Investigaciones en Biodiversidad y Medioambiente (INIBIOMA, UNComahue-CONICET), San Carlos de Bariloche, Río Negro, Argentina

La diversidad microbiana acuática es un componente clave del funcionamiento de los ecosistemas acuáticos. El objetivo del presente trabajo fue estudiar la diversidad del bacterioplancton y fitoplancton en dos lagunas hipereutróficas e interconectadas de la Región Pampeana (Gómez y Carpincho), durante un período de 4 años (octubre 2012 - octubre 2016). Asimismo, se evaluó la covariación existente entre la composición de las comunidades bacterioplanctónicas (BCC) y fitoplanctónicas (PCC). El bacterioplancton se analizó mediante secuenciación masiva del gen 16S ARNr (Illumina MiSeq) y el fitoplancton mediante recuentos al microscopio invertido (Utermöhl). Ambas lagunas mostraron el mismo comportamiento en las comunidades microbianas a lo largo del estudio. Las Actinobacterias representaron alrededor del 21% del total de las unidades taxonómicas operativas (OTUs) bacterianas, seguidas de Proteobacterias (19%), Cianobacterias (15%) y Bacteroidetes (15%), observándose además algunas OTUs bacterianas potencialmente patógenas para humanos (e.g. Rickettsia sp., Aeromonas sp., Legionella sp., Vibrio mimicus). El fitoplancton estuvo dominado por Chlorophyceae (60%), seguido por Cyanobacteria (23%) y Bacillariophyceae (13%), excepto durante las floraciones de cianobacterias (cuando las mismas dominaron). Además, la BCC y PCC presentaron una marcada estacionalidad y una covariación positiva entre ambas comunidades (Test de Mantel r = 0,67 y p = 0,0001; r = 0,63 y p = 0,0001 en Gómez y Carpincho respectivamente). Finalmente, se observó que la diversidad de bacterioplancton sufrió una fuerte disminución durante un evento de floración de cianobacterias (enero-2014).

Proyecto PAMPA2 (CONICET) PICT B 2014-0918 (FONCYT) PICT D 2017-0891 (FONCYT)

90 The monarch butterfly overwintering microbiome: a model for ecology and evolution of host- microbe interactions

El microbioma de hibernación de la mariposa monarca: un modelo para la ecología y la evolución de las interacciones entre microbios y huésped

Roberto Marín-Paredes2, Esperanza Martínez-Romero1, Luis Eduardo Servín-Garcidueñas2. (1) Laboratorio de Microbiología Ambiental y Simbiótica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (2) Laboratorio de Microbiómica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México (Sponsored by Universidad Nacional Autónoma De México)

Insect gut microbiomes seem to be highly dependent on the diet and regulated by host innate immunity. Monarch butterflies migrate from Canada and the United States for overwintering in Mexico. The migration of the monarch butterfly has been in rapid decline. Few studies have surveyed bacterial gut communities from butterflies; the microbiome of monarch butterflies had remained unknown. In this study, we used high-throughput metagenomic sequencing to describe bacterial communities and their genetic potentials in the guts of monarch butterflies collected in overwintering sites in Mexico. We analyzed 60 Gb of unpublished microbiome sequencing data from monarchs collected during springs of 2018 and 2019. Overwintering monarch butterflies have a taxonomically restricted bacterial gut microbiota dominated by acetic acid bacteria. Asaia, an acetic acid bacterium that has been associated as a symbiont of nectar-feeding species, was detected in the guts of monarch butterflies. However, the most highly represented symbiont was an acetic acid bacterium related to the Commensalibacter genus, which was present in all gut communities. We sequenced the genome of Commensalibacter isolate obtained from the gut contents of a monarch butterfly and performed comparative analyses against available Commensalibacter genomes obtained from fruit fly and bee guts. Surprisingly, Commensalibacter genomes are under 2.4 Mb in size and have a GC content of fewer than 37% thus reflecting small AT-biased genomes when compared with free-living acetic acid bacterial genomes. These results along with the available monarch genome make this butterfly an attractive model to understand host-microbe interactions during insect migration and overwintering.

This research was supported by grants from PAPIIT-UNAM (IA208019) and CONACyT-Mexico (154453).

91 Adequate Z-ring localization inAnabaena sp. PCC7120 requires KaiABC circadian clock control

El correcto posicionamiento del anillo Z en Anabaena sp. PCC7120 requiere del control del reloj circadiano KaiABC

Marcial Silva1, Javiera Jiménez2, Jorge Olivares1, Benjamin Mayer3, Peter Graumann3, Mónica Vásquez1. (1) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica De Chile (2) Universidad de Chile (3) Química, Philipps Universität Marburg (Sponsored by Fondecyt Grant 1161232; CONICYT-PCHA/Doctorado Nacional/2016-21160240)

Cyanobacteria are the oldest known organisms with a functional circadian mechanism. Nowadays, it is known that in S. elongatus PCC 7942 (unicellular model) the KaiABC clock temporarily blocks cell division through specific inhibition of Z-ring formation. The absence of the circadian clock does not affect cytokinesis, but it influences the temporality in which the event occurs (without the clock genes , it is impossible to synchronize a cell culture). On the other hand, in Anabaena sp. PCC7120 (multicellular organism) the implications of the absence of the circadian clock are unknown, although certain studies show differences in the cell division timing along its filament. In this study, we evaluated the Z-ring formation dynamics by time-lapse microscopy in kaiABC clock mutants which have a fluorescent ftsZ-sfgfp construction. Using epifluorescence and super-resolution microscopy (SIM), we could determine that kaiABC clock deletion affects the Z-ring middle positioning in the cells which generates in certain conditions that branches of the filament appear (a strange behavior for Anabaena, but typical of the Stigonematales order). Thus, the KaiABC clock circadian regulation would be fundamental for the cell division process inAnabaena sp. PCC7120 (multicellular organism). A very interesting finding considering that this differs totally from studies for unicellular organisms such as Synechococcus elongatus where the cell division process is independent of circadian control.

Fondecyt Grant 1161232; CONICYT-PCHA/Doctorado Nacional/2016-21160240

92 Exploring the bacterial community in cacao rhizosphere as a source of alternatives against cadmium accumulation in the plant

Explorando la comunidad bacteriana en rizosfera de cacao como fuente de alternativas contra la acumulación de cadmio en la planta

Alexander Cordoba1,2, Jeimmy Cáceres2, Esperanza Torres-Rojas3. (1) Laboratorio de Genética Molecular, -, Agrosavia (2) Agronomia - Laboratorio de Agrobiotecnología, Ciencias Agrarias, Universidad Nacional de Colombia (3) Agronomia. Laboratorio de Agrobiotecnología, Ciencias Agrarias, Universidad Nacional de Colombia

Cocoa has a relevant market with a global consumption of 7.5 million tons by 2017/2018. Cacao is mainly produced in Africa and Latin-America. Despite American cacao is recognized for its quality, it has been reported the presence of cadmium (Cd) in chocolate products. An agronomic strategy is reducing the absorption of Cd through the soil bacteria community. However, knowledge about population of Cd-resistant bacteria associated to cacao is scarce. This study was aimed to make a morphological and molecular identification of Cd resistant bacteria; characterize growth, functionality, Cd accumulation and Minimum Inhibitory Concentration (MIC) of isolated bacteria; and detect the presence of the Cd-related gene smtAB. Soil samples from cacao rhizosphere were collected in locations with different levels of Cd in Colombia. Bacteria were isolated in solid media with 6 mg kg-1Cd (CdCl2) and a diversity analysis was performed. Their ability to degrade cellulose, to solubilize phosphates and to fix atmospheric nitrogen was assessed with differential culture media. Strains resistant to 18 mg kg-1 were used in further evaluations. The location with the highest level of Cd (16.5 mg Kg-1, available Cd) showed the highest diversity and unique morphotypes. Pseudomonas putida-GB78 and Burkholderia sp.-NB10 growth was not notably affected in 18 mg kg-1Cd and they showed a MIC of 90 and 140 mg Kg-1Cd, respectively. GB78 had the highest Cd accumulation (5.92 mg/g). Finally, smtAB gene was detected. Overall, the results contribute to the knowledge about Cd-resistant bacteria diversity associated to cacao with the potential to develop biotechnology-based strategies.

93 Expanding the landscape of biosynthetic gene clusters involved in natural product discovery of the Rhodococcus genus

Expandiendo el paisaje de grupos de genes biosintéticos involucrados en el descubrimiento de productos naturales del genero Rhodococcus

Agustina Natalia Undabarrena1, Ricardo Valencia1, Andres Cumsille1, Eduardo Castro-Nallar2, Beatriz Cámara1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Quimica, Centro de Biotecnología Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María (2) Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andres Bello (Sponsored by Beatriz Cámara)

Natural products (NPs) provide an unsurpassed resource in drug discovery to overcome multi-resistant pathogenic diseases. NPs are synthesized by secondary metabolic pathways called biosynthetic gene clusters (BGCs), whose genes are physically clustered together and encode for the production of (a) specialized metabolite(s). The undergoing development of whole genome sequencing techniques has allowed to reveal the untapped potential of microorganisms through genome mining. However, scarce knowledge is provided in genome data regarding the evolution patterns modeling BGCs structure and distribution, which ultimately has an important effect in the production of NPs. Comparative genomics is a useful tool when dealing with high-throughput data, especially when classifying BGCs into gene cluster families (GCFs) that allow dereplication and prioritization of the ones encoding the most promising compounds. We aimed to explore the Rhodococcus genus and we used one of our Chilean fjord- derived marine strains as a proof of concept to perform an in-depth comprehensive analysis of specialized BGCs. A phylogenomic inference is presented, revealing mostly four major clades. We developed a robust pipeline for performing comparative genomics applying biological criteria in order to avoid redundant entries. A BGC network was performed, revealing that the main biosynthetic category was encompassed by non-ribosomal peptide synthetase (NRPS) pathways, where 44 GCFs were retrieved. Similarity scores were too low for their product identification, suggesting that this vast group remains mostly uncharacterized. Interestingly, a strong correlation with phylogeny -rather than isolation source- was found, revealing clade-specific GCFs along with the evolution patterns unveiling the production of NPs.

FONDECYT Postdoctorado N° 3180399, FONDECYT Regular N° 1171555, Conicyt PIA ACT172128.

94 The story of a widespread generalist, the phytoplankton Emiliania huxleyi

La historia de un generalista extendido, el fitoplancton Emiliania huxleyi

Peter von Dassow1, Uwe John2. (1) Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica De Chile (2) Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research

The phytoplankter Emiliania huxleyi is exceptionally widely distributed, being a dominant coccolithophore inall but polar waters of the surface ocean. None of the closest relatives of E. huxleyi, all taxonomically classed within Gephyrocapsa, exhibits such a wide ecological distribution. This makes theEmiliania /Gephyrocapsa genus interesting for studying what processes facilitate or inhibit adaptation to new and changing environments. Transcriptomic and genomic information was used to select 100 single-copy shared genes among four Gephyrocapsa species and 13 strains of E. huxleyi for coalescent multi-locus nuclear phylogenies. Gephyrocapsa muellerae, ericsonii, and parvula form a nuclear clade that shares loss of haploid-specific genes. E. huxleyi appeared 291 kya in the fossil record, however, apart from one clade, the principal radiation is dated in the nuclear tree at 87.9 kya, coincident with when E. huxleyi became dominant in the fossil record. Incongruences between nuclear, chloroplast, and mitochondrial phylogenies suggest either introgressive hybridization with E. huxleyi, in spite of haploid gene loss, or incomplete lineage sorting. Meanwhile, genome-wide analysis reveals 16% of SNPs specific for each clades affect CDSs. Among affected CDS, 13708 protein-coding genes distinguish theG. ericsonii-parvula clade with Ka/Ks of 1.61, 778 distinguish a tropical E. huxleyi clade with Ka/Ks of 1.44, and 167 distinguish the principal temperate E. huxleyi clade with Ka/Ks of 1.32. Affected proteins are broadly distributed among KOG functional classifications. Thus, the recent evolutionary history and forces acting on this group may involve positive selection.

FONDECYT 1181416 FONDECYT 1141106 ICM IC120019 FONDOS INTERNOS PUCCH VRI N° PBI1815

95

POSTERS

Gene pool variability, diversity and evolution of Superintegron from non-O1 Vibrio cholerae

Variabilidad del pool genético, diversidad y evolución del Superintegron de Vibrio cholerae no O1

Michel Francisco Abanto1, Andy Powell2, Charlotte Ford2, Andres Santos1, Craig Baker-Austin2, Jamie Martinez- Urtaza2. (1) BIOREN, Universidad de La Frontera (2) Centre for Environment, Fisheries and Aquaculture Science, UK (Sponsored by CEFAS - Seedcorn)

Vibrio cholerae genome consists of two chromosomes; the small chromosome carries a large gene capture and excision system of ~120 kbp called superintegron. The superintegron is a constitutive element but is source of genetic variation due to lateral gene transfer. Characterization of the superintegron gene content from genomes obtained by next-generation high-throughput sequencing with short reads has been extremely challenging due to presence of hundreds of repetitive sequences (~100bp length) which are difficult to assemble accurately. The aim of this work was to evaluate the gene diversity and structure of the superintegron in nontoxigenic V. cholerae non O1-non 139 isolated from waters samples collected in a low salinity lagoon in Southern England. Genomes from three isolates were sequenced using both Illumina and Nanopore technologies We applied a hybrid de novo assembly of Illumina/ Nanopore reads produced a complete closed genome sequence of the chromosome and plasmids to obtain a high- quality representative sequence for these strains. Additional non-O1 and reference V. cholerae genomes from different sources and geographical regions were included in study. Based on integrase (intI4) gene, a primary recombination site (attI), the large arrays of gene cassettes and the V. cholerae repeat (VCR), we were able to recover the entire superintegron region. Comparative analyses of this region among the genomes included in the study revealed the presence of a novel gene repertoire linked to the nature of the strain, suggesting that variability of gene pool in the cassette is influenced by the environment and may play a critical role in niche adaptation in transits between habitats. CEFAS; BIOREN-UFRO

97 Activity of marine ammonium recycling microbes in a experimentally growing plastisphere

Actividad de microorganismos marinos recicladores del amonio en una plastisfera crecida bajo condiciones experimentales

Carla Angélica Acuña1, Hermann Peña 2, Hector Levipan2, Marcela Cornejo3, Verónica Molina3, Roberto Orellana2. (1) Universidad Andrés Bello (2) biología, ciencias naturales y exactas, Universidad de Playa Ancha de Ciencias de La Educación (3) escuela ciencias del mar, Pontificia Universidad Católica de Valparaíso (Sponsored by Verónica Molina Trincado)

Los microplásticos (< 5mm) son la forma más abundante de plástico encontrada en el océano, distribuyéndose en grandes extensiones (e.g., 67 ítems /m2 en los grandes giros). El plástico, como otras partículas, es rápidamente colonizado por microorganismos marinos quienes forman una biopelícula o “Plastísfera”, incluyendo potenciales degradadores del plástico y microorganismos clave de los ciclos biogeoquímicos. El objetivo de este estudioes determinar la contribución de grupos funcionales del ciclo del nitrógeno en la plastísfera crecida experimentalmente (durante 30 días, evaluada por epifluorescencia) sobre micropartículas de tereftalato de polietileno y polipropileno (PET y PP), mediante técnicas moleculares itag-16Sr RNA, qPCR del gen 16S rRNA y subunidad A del amonio moonooxigenasa (amoA) de bacterias amonio oxidantes (betaproteobacterias-BAO), utilizando RNA como templado. Los resultados mostraron que la estructura y composición microbiana encontrada sobre PET & PP difieren entre sí, encontrándose 33 phyla activas, de las cuales la mayor contribución fue asociada a Nitrospinae, Planctomycetes, Proteobacteria, Firmicutes, Bacteriodetes y Verrucomicrobia. Además, mayoritariamente en PP, en comparación a PET se observó un enriquecimiento de grupos funcionales como: bacterias y arqueas amonio oxidantes, bacterias nitrito oxidantes aeróbicas, bacterias ANAMMOX (Anaerobic ammonium oxidizers). Las BAO alcanzaron >1% de la contribución en las librerías de secuencias en comparación <0.01% en el agua de mar superficial, lo que sugiere que este plástico propiciaría un ambiente favorable para grupos vinculados a partículas. En total, nuestros resultados indican que la plastisfera podría ser un “hotspot” del reciclaje de nutrientes, tanto aeróbicos como anaeróbicos del ciclo del nitrógeno en el océano.

FONDECYT #1171324 (2017-2020) Nitrite loop in aquatic ecosystems, an example of environmental microbiome cooperation on nitrogen cycle.

98 Isolation of single bacterial cells from rhizosphere of wheat plants using flow sorting techniques and their potential as PGPR

Aislamiento de células bacterianas individuales desde la rizosfera de planta de trigo utilizando técnica de cell sorting y su potencial como PGPR

Macarena Araya1, Milko Jorquera1,2, Niza Inostroza1, Rilling Joaquin1, Jacquelinne Acuña1,2. (1) Laboratorio de Ecología Microbiana Aplicada (EMAlab), Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera (2) Network for Extreme Environment Research (NEXER), Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera

Plant rhizosphere harbors thousands of different bacterial taxa, which can play a crucial role in plant health and productivity. However, only 0.1% bacteria are culturable under laboratory conditions. This limitation underestimates the total diversity of the rhizobacteria, particularly of bacterial groups defined as ‘rare taxa’ or ‘unculturable’, and which commonly occur in low abundance. The objective of this study was to isolation and characterization of bacterial strains from rare taxa by using flow sorting to select small bacterial cells. Bacterial cells were stained with SYBR Gold and sorted into single 96-well plates with LB, NM-1, and Oligotrophic media. Rhizobacterial growth were observed in 64 of well, but only 19 strains were able to growth into successive subculture. Among them, 9 isolates were able to identified on partial sequencing of 16S rRNA genes. The isolated strains were classified as members of non-common or rare bacterial taxa in soils such as Methylobacterium, Mycolicibacterium, Novosphingobium and Labrys genera. One strain from Paraburkholderia, Acinetobacter, and Staphylococcus genera also were isolated. Interestingly, a higher portion of isolates (90%) showed PGPR traits such as: ACC deaminase activity (80%), auxin production (50%), and phosphorus solubilization (20%). Finally, PCR amplification revealed the occurrence of ACC-deaminase gene (acdS), nitrogen fixation gene (nifH), and alkaline phosphomonoesterase gene (phoD) from bacterial isolates of rare taxa. Flow cells sorting in combination with 96-wells plate represents an attractive strategy to isolate rare bacterial taxa with potential as PGPR for cereal crops, such as wheat.

Acknowledgments: This study was financed by FONDECYT Iniciacion Project No. 11160112 and FONDECYT Regular Project No. 1120505.

99 ACC-deaminase activity of bacteria isolated from the phyllosphere, endosphere and rhizosphere of the Antarctic vascular

Actividad ACC-desaminasa de bacteria aisladas desde la filósfera, endósfera y rizósfera de plantas vasculares Antárticas

Jacquelinne Jovanka Acuña1,2, Macarena Araya1, Niza Inostroza1, Fumito Maruyama3, Milko Jorquera1,2. (1) Laboratorio de Ecología Microbiana Aplicada (EMAlab), Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera (2) Network for Extreme Environment Research (NEXER), Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera (3) Department of Microbiology, Graduate School of Medicine, Kyoto University

The plant growth promoting bacteria (PGPB) play a crucial role of plant health and growth, providing beneficial mechanisms to plants survive under extreme conditions. 1-aminociclopropane-1-carboxylate (ACC) deaminase producing bacteria are widely studied to alleviate a variety of stresses in plants. However, the presence of ACC deaminase-producing bacteria in plants that naturally occur in stressful ecosystems as well as the potential PGPB activity in agriculturally relevant plants has been poorly explored thus far. Here, we isolated and characterized ACC deaminase-producing bacteria from Antarctic vascular plants Deschampsia antarctica and Colobanthus quitensis. Plants and their rhizospheric soils samples were collected from South Shetlands Islands and Antarctic peninsula during Scientific Antarctic Expedition ECA53-2017. Among 578 isolated, 31 % were able to grown on DF-ACC media as a sole source of nitrogen and were distributed in 83 rhizospheric strains, 45 root endophytes and 52 phyllosphere strains. Our results showed an ACC deaminase activity ranged from 0.28 to 39.56 μmol α-ketobutyrate mg−1h−1, where rhizobacterial strains showed a higher activity in comparison with strains isolated from endosphere and phyllosphere. Based on 16SrRNA gene sequences, isolates strains were identified as members of the Enterobacteriales order (mainly Pseudomonas and Serratia). This study demonstrated that PGPB were associated with Antarctic vascular plants offers a promising potential source of novel PGPB to alleviate salt stress in plants.

This study was financed by INACH RT-02-16, FONDECYT Iniciacion Project No. 11160112 and FONDECYT Regular Project No. 1120505.

100 Physical, microbiological and antimicrobial resistance characteristics of water coming from well and distributed in ditch for surface irrigation of vegetables

Características físicas, microbiológicas y de resistencia antimicrobiana de agua proveniente de pozo y distribuida en acequia para riego por surco en hortalizas

Aiko Adell2,1, Constanza Diaz1, Carla Barría1, Daniela Cea3, Cristían Barrera3, Robert Atwill4, Jorge Olivares-Pacheco5, Aníbal Araya-Figueroa5, Pilar Gil3. (1) Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andrés Bello (2) Millennium Nucleus for Collaborative Research on Bacterial Resistance (MICROB-R) (3) Pontificia Universidad Católica de Chile (4) Western Institute for Food Safety and Security, University of California, Davis (5) Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso

Actualmente el mercado está exigiendo elevados estándares de inocuidad en los productos vegetales destinados al consumo humano. Dentro de las principales fuentes de contaminación de las hortalizas se encuentra el riego con agua microbiológicamente contaminada, por lo cual conocer la calidad del agua de riego es fundamental. En este estudio se evaluó la presencia de Coliformes fecales, Escherichia coli y Salmonella entérica en diversos puntos de sistemas de riego por surcos abiertos para hortalizas. Se procesó agua de riego para detectar Coliformes fecales y E. coli siguiendo la metodología indicada en la Norma Chilena ME-712.02-005, mientras que para Salmonella se utilizó ultrafiltrado, filtración de membrana, cultivo en agar y PCR. Se detectó la presencia de Coliformes fecales yE. coli en todos los puntos muestreados, y S. enterica en dos sitios. Estos datos preliminares indican que hay presencia E. coli y S. enterica en las aguas de riego que son utilizadas para irrigar hortalizas. A su vez, se realizó una búsqueda de bacterias resistentes a los antibióticos. Para ello 50 mL de agua fueron concentrados utilizando un flitro de 0,22 µm, para luego ser sembrados en placas de agar R2A incubándose a 3 temperaturas 37, 25 y 15ºC. Se construyeron bancos con los morfotipos de colonias a las 3 temperaturas mencionadas, los que a su vez fueron desafiados con los antibióticos imipenem, ceftazidima y ciprofloxacina. Se encontraron bacterias resistentes a imipenem y ciprofloxacina en todas las temperaturas; mientras que bacterias resistentes a ceftazidima sólo aparecieron a los 25 y 37ºC.

Fuentes de financiamiento: Programa Conicyt Acción Regional (ARII600006), FONDECYT de Iniciación 11160116 e Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo, Gobierno de Chile.

101 Microbial source tracking of fecal contamination in Maipo and Maule rivers in Central Chile

Rastreo de fuentes microbianas de contaminación fecal en los ríos Maipo y Maule en Chile central

Constanza Diaz1, Carla Barría1, Gabriela Gaona1, Nicolas Villagra2, Leonardo Vera3, Woutrina Smith4, Minji Kim5, Aiko Adell6,1. (1) Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello (2) Facultad de Medicina, Facultad de Ciencias de la Vida, Universidad Andrés Bello (3) Escuela Ingeniería Ambiental, Facultad de Ciencias de la Vida, Universidad Andres Bello (4) One Health Institute, School of Veterinary Medicine, University of California, Davis (5) Department of Civil and Environmental Engineering, University of California, Davis (6) Millennium Nucleus for Collaborative Research on Bacterial Resistance (MICROB-R)

Introduction: Waterborne infectious diseases cause an estimated of 2.2 million deaths per year. Contamination with feces is the main source of pathogens to surface water; therefore determining the origin of the fecal source contaminating surface waters is crucial, especially if these have an agricultural use. While fecal coliforms are used as indicators, these do not provide information of the source of contamination. Host specific microorganism such as Cryptosporidium, Giardia and Salmonella enterica are used to trace sources of fecal contamination in surface waters. The main objective of this work was to determine the impact of land use on fecal contamination in surface water in Maipo and Maule rivers in Central Chile Methods: Surface water was collected from Maipo and Maule rivers every three months for two years. Twelve sampling sites representing different land use (natural, agricultural, urban and livestock areas) were selected. Fecal coliforms were determined by the most probable number (NMP) method based on Chilean regulation (1,000 coliform/ ml is permitted). Cryptosporidium and Giardia were detected by means of an ultrafiltration system, the EPA method 1623 and PCR confirmation. Salmonella was isolated in agar XLT-4 and bismuth sulfite medium and confirmed by PCR for typhoidal and non-typhoidal Salmonella. Results: Up to 30,000 coliforms/ml were found in the Maipo river in the urban area in January 2018. Zoonotic genotypes of Giardia and bovine genotypes of Cryptosporidium were detected in urban areas in both rivers. One typhoid Salmonella and five non-typhoidal Salmonella were also found in urban sites of Maule river.

We acknowledge the financial support received from the FONDECYT 11160116

102 Antimicrobial resistance in water in Latin America and the Caribbean: Available research and gaps

Resistencia antimicrobiana en agua en América Latina y en El Caribe: identificación de investigaciones disponibles y brechas

Dacil Rivera1, Andrea Moreno Switt2,1, Marisa Caipo3, David Nowell3, Aiko D. Adell2,1. (1) Escuela de Medicina Veterinaria, Facultad de Ciencias de la Vida, Universidad Andres Bello (2) Millennium Nucleus for Collaborative Research on Bacterial Resistance (MICROB-R) (3) Oficina Regional de la FAO para América Latina y el Caribe, Organización de las Naciones Unidas para la Alimentación y la Agricultura

Introducción: La resistencia a los antimicrobianos (RAM) es uno de los problemas de salud pública más importantes estimándose 10 millones de muertes anuales para el año 2050. El medio ambiente (agua, suelo) tiene un rol en la diseminación de RAM, que es cada vez más transcendental, sobre todo en la diseminación de bacterias clínicamente relevantes. A pesar de que se han realizado investigaciones sobre RAM en América Latina y el Caribe (ALC), estas no han sido analizada en conjunto. Objetivo: Determinar el estado del conocimiento e identificar las brechas en la información sobre la RAM en agua en ALC por medio de una revisión exploratoria que identifique los artículos científicos que han abordado la temática. Método: El proceso de selección de los artículos científicos consistió en las cuatro fases de una revisión exploratoria centrándose en ocho temas de interés. Resultados: La mayoría de las investigaciones se han realizado en la década 2008-2017. Brasil fue el principal contribuyente al estudio de RAM en la región. Los temas en agua más investigados son detección fenotípica de RAM (tema VIII), detección de genes de resistencia a antimicrobianos (GRA) (V), y degradación de la RAM (III). Se identificó escasa investigación en insectos, productos agrícolas, organismos acuáticos, ganado, y aguas residuales diferentes de las aguas residuales hospitalarias. Investigaciones en Plagas emergentes y enfermedades con impacto potencial en la producción de RAM (VII), Impacto del uso de antimicrobianos en la producción agrícola (IV) y Efectos negativos de la RAM en vida silvestre (II) son escasas.

FAO, Oficina Regional para América Latina y el Caribe financió este proyecto. También reconocemos las fuentes de financiamiento: FONDECYT 11160116 e Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo, Gobierno de Chile.

103 Phytoremediation potential of rye and ryegrass for the treatment of a petrochemical sludge

Potencial de fitorremediación de centeno y raigrás para el tratamiento de un barro petroquímico Ana Carolina Agnello1, María Teresa Del Panno1. (1) Centro de Investigación y Desarrollo en Fermentaciones Industriales (CINDEFI) - CONICET

Petrochemical sludges (PS) are wastes generated from petroleum production. One of the present challenges of petrochemical industry is finding waste management solutions protective both for human health and the environment. The aim of this study was analysing the phytoremediation potential to treat a PS (total hydrocarbons: 62782 mg Kg- 1) rich in recalcitrant resins and asphaltenes. A pot experiment using a mix of PS (at 0, 5, 10 and 25% w/w) with soil was the substrate for rye (Secale cereale) and ryegrass (Lolium perenne) growth. After 120 d, plants were harvested to determine dry biomass. Additionally, chemical (i.e. petroleum hydrocarbons by IR and GC-FID) and microbiological (i.e. enumeration of CFU of heterothrophs and MPN of hydrocarbon degraders, number of 16S gene copies by qPCR and 16S fingerprinting by PCR-DGGE) analyses were performed. Plants were able to withstand pollutant stress in the presence of the PS at 25% w/w without negatively affecting plant biomass. Indeed, there was a significant increase in ryegrass shoots and rye roots. A significant reduction in total hydrocarbons in the presence of rye (38%) and ryegrass (46%) was observed. However, this reduction was not significantly different from that attained without plants (54%). Moreover, bacterial community structure in these treatments was alike (67% similarity) as revealed by the clustering of PCR-DGGE banding patterns. Although this demonstrates that plants did not enhance total hydrocarbon removal through the rhizosphere effect, the differences observed through GC-FID profiles suggest that a direct role of plants in hydrocarbon uptake is still open to question.

Agencia Nacional de Promoción Científica y Tecnológica (Argentina). Proyecto PICT 2016-0947

104 Changes in the structure and composition of oceanic bacteria exposed to high levels of pCO2 and low pH during a short-term microcosm experiment in the eastern Tropical South Pacific (ETSP) in northern Chile

Cambios en la estructura y composición de bacterias oceánicas expuestas a altos niveles de pCO2 y bajo pH durante un experimento de microcosmos en el Pacífico Sureste Tropical (ETSP), norte de Chile

Paulina Aguayo1, Víctor Campos 2, Carlos Henríquez 3, Rodrigo De La Iglesia4, Francisca Olivares5, Osvaldo Ulloa6, Cristian Vargas6. (1) sistemas acuáticos , Ciencias Ambientales, Universidad de Concepción, Instituto milenio de Oceanografía IMO (2) Microbiología, Ciencias Biológicas , Universidad de Concepción (3) Oceanografía, Universida de Concepción, Instituto Milenio de Oceanografía (IMO) (4) Genetica molecular y Microbiología , Pontificia Universidad Católica de Chile (5) Oceanografía, Universidad de Concepción, Instituto milenio de Oceanografía (6) Oceanografía, Universidad de Concepción,Instituto Milenio de Oceanografía (IMO)

El aumento de pCO2 y la disminución del pH alteran la química del océano, alterando la biogeoquímica, la estructura comunitaria de microorganismos marinos y el funcionamiento del ecosistema. Nuestro objetivo fue evaluar los efectos del alto pCO2 / bajo pH en la diversidad genética de la comunidad bacteriana en muestras de agua de una costa norte de Chile. Los niveles de pH investigados fueron (pH 8.05, pCO2 403 ppm) y pH 7.61 (pCO2 1162 ppm), que representan la situación actual y los escenarios de acidificación proyectados para el año 2100. La composición y la abundancia relativa se analizaron por medio de secuenciación del gen que codifica la subunidad menor del ribosoma (16S rRNA). Los resultados se contrastaron con las abundancias celulares obtenidas por citometría de flujo y las variables fisicoquímicas asociadas. Los taxones más abundantes en muestras de agua fueron SAR11 (Alphaproteobacteria), SAR324 (Deltaproteobacteria), Artic96BD-19 (Gammaproteobacteria). El análisis genético de todos los microcosmos mostró predominio de los taxa Alteromonadales, Alcanivoracaceae, Rhodobacterales, pero en microcosmos de pH bajo / alto pCO2 predominó el phylum planctomicetales que no se detectó en la estación T5 y tuvo una baja representación en el control y alto pH / bajo microcosmos de pCO2. Nuestros hallazgos que cambian en pH / pCO2 tienen el potencial de causar cambios en la composición bacteriana y, por lo tanto en los ciclos biogeoquímicos. Los resultados generados evaluarán la vulnerabilidad y la resistencia de los microorganismos frente a los cambios resultantes de la acidificación del océano.

Chilean National Commission for Scientific and Technological Research (CONICYT) grant AUB 150006/12806. FONDECYT POSTDOCTORADO 31707032

105 Novel hypothetical protein involved in cell division ofAnabaena sp. PCC7120

Nueva proteína hipotética involucrada en división celular deAnabaena sp. PCC7120

Blanca Aguila1,2, Nicole Trefault 3, Mónica Vásquez 1. (1) Genética molecular y Microbiología , Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Programa de Doctorado en Genómica Integrativa, Vicerrectoría de Investigación, Facultad de Ciencias , Universidad Mayor (3) Centro GEMA-Genómica, Ecología y Medio Ambiente, Vicerrectoría de Investigación, Facultad de Ciencias , Universidad Mayor

Cell division in bacteria require the orchestration of several proteins included in the complex named divisome. Such a process involves the formation of the Z-ring in the middle of the cell, herein constricting cells to give daughter cells. FtsZ is one of the main protein component of the Z-ring. Importantly, just few proteins have been identified in cyanobacterial cell division. In this work, we evaluated the possible role of an undescribed conserved hypothetical protein in the cell division of a multicellular cyanobacteria,Anabaena sp. PCC7120. To determine the function of this protein, gene disruption by homologous recombination and triparental conjugation was performed. The construct included spectinomycin resistance cassette to select the mutant cells. Using specific primers for our construct, uncompleted segregation was found in the Anabaena sp. PCC7120 mutant. The phenotype and cell division of Anabaena sp. PCC7120 mutant was evaluated by optical and confocal microscopy, respectively. Although segregation was not complete, the mutant shows variation in the plane division compared to the wild type strain. In addition, loss of the orientation of cell division plane was found in the Anabaena sp. PCC7120 mutant. The septum detection was done by immunofluorescence detection against FtsZ and image acquisition by confocal microscopy. These results suggest that this hypothetical protein is in fact involved in the cell division of filamentous cyanobacteria.

Acknowledgments: Fondecyt Nº 1161232, Fondecyt Nº 1190879. BA PhD fellowship Universidad Mayor.

106 Phenotypic, biochemical and genomic characterization of the cypermethrin degrading and biosurfactant producing bacterial strains isolated from the Northern Chilean Patagonia

Caracterización fenotípica, bioquímica y genómica de cepas bacterianas que degradan cipermetrina y producen biosurfactantes, aisladas desde la Patagonia del Norte de Chile

Patricia Isabel Aguila1, Mauricio González2, Jonathan Maldonado3,2, Alexis Gaete2. (1) Escuela de Tecnología Médica, Sede Puerto Montt, Universidad Austral de Chile (2) INTA-Universidad de Chile (3) Pontifica Universidad Catolica (Sponsored by Universidad Austral De Chile)

Pesticides represents a problem on the environmental marine ecosystems. One of these pesticides correspond to cypermethrin, pesticide used extensively like antiparasitic treatment in the aquaculture industry. The objective of this study was to isolate and characterize species of bacteria with cypermethrin degrading capacity and biosurfactant- producing activity in sediment samples of southern Chile. Eleven bacteria were isolated trough enrichment procedure from cypermethrin contaminated sediment samples. Isolates were identified by 16S rDNA gene sequencing, and the result showed that the strains belonged to three different genera, correspond to Pseudomonas, Rhodococcus and Serratia. Isolates were tested for biosurfactant production and emulsification activity. All isolates grew up in presence of cypermethrin, however, four isolates have a biosurfactants capacity based their high emulsification index

E24, corresponding to the strains MS13 and MS16 (Rhodococcus genera) and MS15 and MS19 (Pseudomonas genera). These strains were genome sequenced and the esterase genes was identified in silico. These novel cypermethrin- degrading and biosurfactant-producing bacterial strains could have a biotechnological potential for bioremediation on marine sediments contaminated with cypermethrin.

Proyecto DID-SEDE PM 54611210 Escuela de Tecnología Médica, Vicerrectoría Sede Puerto Montt, Universidad Austral de Chile.

107 Community assembly of lake bacterioplankton over two years is primarily governed by homogeneous selection

La estructura comunitaria del bacterioplancton de lago, a lo largo de 2 años, es principalmente gobernada por selección homogenia

Pablo Aguilar1, Ruben Sommaruga1. (1) Lake and glacier ecology research group, Institute of Ecology, University of Innsbruck

One major goal in microbial ecology is to establish how important deterministic and stochastic processes are in structuring bacterial communities. Disentangling the role of these ecological processes allows us to explain and predict how diversity and community will change under different spatial and temporal scales. However, there is a limited understanding of the relative contribution of ecological processes that structure the microbial communities in time. Here, we analyzed the bacterial community composition and diversity of two lakes of different trophic state during two consecutive years. Further, we tested the turnover of the bacterial community in the oligotrophic lake also on a weekly and daily scales. Homogeneous selection was the strongest process (explaining 66.7% of community turnover) acting over the annual scale, but at a weekly and daily scale, homogenizing dispersal was themost important (explaining 55% of community turnover). Both lakes showed the same relative contribution of the main processes (homogeneous selection and homogenizing dispersal) at the annual scale, despite differences in bacterial diversity and dynamics between them. Our results demonstrate how important temporal changes are at different scales to explain the forces that govern microbial communities. Further, our study validates for the first time and on a quantitative basis the dominance of deterministic processes in freshwater environments.

This work was supported by the Austrian Science Fund [FWF, P24442-B25] to R.S. PA was supported by a doctoral fellowship from the University of Innsbruck (Austria) and CONICYT BecasChile 72190053 (Chile)

108 Design of analogues with greater antimicrobial potential from prepro-peptides identified from the skin of Boana Pulchella (Anura: Hylidae)

Diseño de análogos con mayor potencial antimicrobiano a partir de prepro-péptidos identificados en la piel deBoana Pulchella (Anura: Hylidae)

Silvana Aguilar1, Natalia Lorena Cancelarich1, Néstor Guillermo Basso2, Luis Orlando Pérez3, Mariela Mirta Marani1. (1) IPEEC - CONICET, Instituto Patagónico para el Estudio de los Ecosistemas Continentales (2) IDEAus - CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina (3) IPCSH - CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas, Puerto Madryn, Argentina

Debido a que habitan ambientes húmedos y con una alta densidad de microorganismos, los anfibios secretan en su piel un variado arsenal de péptidos antimicrobianos (PAMs). Éstos presentan un potencial tecnológico en la búsqueda de nuevas herramientas alternativas para combatir microorganismos patógenos pero su aplicabilidad se ve limitada por su citotoxicidad. Cambios racionales en la estructura primaria podrían maximizar o ampliar el rango de actividades biológicas a través de análogos sintéticos terapéuticos, mejorando su capacidad antimicrobiana y manteniendo un balance óptimo entre estabilidad y citotoxicidad. En el presente trabajo se identificaron y caracterizaron 5 nuevos prepro-péptidos a partir de la extracción del ARNm, de la piel de Boana pulchella (Bpc), y posterioramplificación, clonación y secuenciación de los DNAc específicos. Los mismos presentaron carga neta positiva, PM entre 1870 y 1996 Da y estructura 3D teórica de tipo α-hélice anfipática, con probabilidades de ser PAMs de hasta 0.92. Sin embargo, también fue alta la predicción de actividad hemolítica (> 0.8). Con el objetivo de mejorar su potencial terapéutico se realizó un exhaustivo análisis de la relación estructura-actividad (SAR) utilizando las herramientas informáticas PEP- FOLD, HeliQuest, ProtParam, CAMPR3, DBAASP y Mutator. Se diseñaron y analizaron análogos in silico obteniendo 7 nuevas estructuras con un mayor espectro de acción (bacterias y hongos) y una disminución significativa en su actividad hemolítica. Estos péptidos están siendo sintetizados para su posterior purificación y evaluación experimental de su actividad antimicrobiana, hemolítica y citotóxica.

Esta investigación se enmarca dentro de los proyectos CONICET PIP no. 11220120100050OC y ANPCyT PICT no. 2278- 2017. SA y NLC agradecen a CONICET por las becas doctorales otorgadas.

109 Microbial diversity in groundwater samples from an agricultural shallow aquifer and its underestimation by conventional filtering methods

Diversidad microbiana en muestras de agua subterránea de un acuífero somero agrícola y su subestimación por métodos convencionales de filtrado

Eduardo Javier Aguilar-Rangel1, Rocio Jetzabel Alcántara-Hernández2, Blanca Lucía Prado-Pano2, Soledad Vázquez- Murrieta3, Paulina Estrada-de Los Santos3. (1) Departamento de Ciencias Ambientales y del Suelo, Instituto de Geología, Universidad Nacional Autónoma de México (2) Ciencias ambientales y del suelo, Instituto de Geología, Universidad Nacional Autónoma de México (3) Laboratorio de Microbiología Industrial, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional

Groundwater systems have gained attention during the last years because of their biodiversity and relevance in water quality. Thus, multiple studies have been conducted to study their microbiota, revealing several underlying attenuation pathways. The recent use of NGS has allowed us to make deeper insights into the microbial ecology of groundwater; however, these samples tend to have a low number of microorganisms. So, it is necessary to concentrate the biomass by filtration techniques with 0.22 um pore size membranes. Nonetheless, this practice could diminish the diversity estimates owing to size of some microorganisms. In this study, we evaluated the bacterial diversity in groundwater samples and its underestimation by filtering through 0.22 um membranes, by adding an extra filtering step with 0.1 um pore size membranes. The samples here used were obtained from a shallow aquifer at different sampling times. mgDNA was extracted and the 16S rRNA gene analyses were made. Our results showed that it was still possible to recover DNA in 0.1 um pore size membranes at all sampling times. The survey showed a high 16S rRNA diversity at both kind of samples: 0.22 um samples had a H’>3, while 0.1 um samples, that also harbored H’ >2. Also, according to metabolic prediction based on the 16S rRNA gene sequences, it was possible to recover metabolisms related to N-cycle or xenobiotics degradation at 0.1 um samples. So, it is important to consider the size of the pore in filtering membranes, because 0.22 um filtration can underestimate the microbial diversity.

This work was supported by the Consejo Nacional de Ciencia y Tecnología, Proyecto de Ciencia Básica [SEP-CONACYT 256332].

110 Cyanobacterial Characterization from Microbialites of lake Alchichica and lake Bacalar

Caracterización de cianobacterias en Microbialitas del lago Alchichica y laguna Bacalar

Bernardo Águila-Salgado1, Alfredo Francisco Yánez Montalvo2, Itzel Becerra Absalón3, Rocio Jetzabel Alcántara- Hernandez4, Gustavo Alberto Montejano Zurita3, Luisa Isaura Falcón Álvarez1. (1) Laboratorio de Ecologia Bacteriana, Instituto de Ecologia, Universidad Nacional Autonoma de Mexico (2) Departamento de Sistematica y Ecologia Acuatica, Ecosur, Universidad Nacional Autonoma de Mexico (3) Ficologia, Facultad de Ciencias, Universidad Nacional Autonoma de Mexico (4) Laboratorio de Biogeoquimica, Instituto de Geologia, Universidad Nacional Autonoma de Mexico

We described and characterized cyanobacterial diversity in microbialites from crater lake Alchichica, (Puebla, Mexico), and Bacalar lagoon (Quintana Roo, Mexico), using culture dependent and independent approaches. Fresh microbialite samples were examined by optical microscopy and cyanobacterial taxa were characterized by standard morphological methods. In addition, a molecular characterization was done with a clone library approach fora cyanobacterial-conserved 16S rRNA region plus 16S rRNA high throughput DNA sequencing. Alchichica crater lake microbialites exhibited a vast diversity of Nostocales and Chroococcales with Pleurocapsales as the main components present in the 30 m depth microbialites, suggesting an important role for microbialite formation. In Bacalar lagoon the northern sites showed high diversity of cyanobacteria while southern sites exhibited low diversity, with a dominance of green algae. In both, crater lake Alchichica and Cenote Azul, a sinkhole within Bacalar lagoon, we observed a taxonomic relationship between depth and the cyanobacterial diversity associated to microbialites: Nostocales, Oscillatoriales and filamentous Synechococcales were associated with shallow depths (3-10 m); while Chroococcales and Pleurocapsales were more abundant at deeper zones (10-30 m). In addition, coccoid Synechococcales and other Picocyanobacteria were found along all depths, without any specific distribution pattern.

This work was supported by UNAM-DGAPA-PAPIIT IA209516 with the project title “El componente bacteriano y su potencial biogeoquímico en sedimentos y microbialitas de un sistema salino alcalino”

111 Characterization of endophytic microbiota inAraucaria araucana to identify microorganisms related to foliar damage

Caracterización de la microbiota endofítica en Araucaria araucana para identificar microorganismos relacionados con el daño foliar

Jaime Alarcón1, Guus Teunisse2, Francisca Venegas2, Gabriela Jiménez2, Freddy Boehmwald2, Eduardo Castro-Nallar1. (1) Centro de Bioinformática y Biología Integrativa (CBIB), Facultad de Ciencias de la Vida, Universidad Andrés Bello (2) Fundación UC Davis Chile Life Sciences Innovation Center

En el año 2016, la Corporación Nacional Forestal (CONAF) reportó un masivo daño foliar y muerte de individuos de todas las edades de Araucaria araucana, en toda su distribución natural en Chile y Argentina. Debido a su sintomatología, el fenómeno fue denominado Daño Folia de la Araucaria (DFA) y cuyo origen aún es desconocido. A través de secuenciación amplicon del gen bacteriano 16S y de la región fúngica ITS, llevamos a cabo una caracterización de la microbiota endofítica de Araucaria araucana, para identificar microorganismos que puedan estar relacionados con el DFA. Más de 600 muestras fueron obtenidas en 2017 y 2018 desde 10 sitios de la Cordillera de los Andes y Nahuelbuta, desde tejido vegetal (acícula, rama, tronco, raíz) y suelo asociado a árboles fenotípicamente sanos o con sintomatología DFA y pertenecientes a 3 niveles etarios (renoval, juvenil, adulto). Nuestros resultados indican que la composición de microorganismos endofíticos de A. araucana es tejido dependiente y esta estructurada por la edad del árbol y región geográfica de origen. Además, una ASV taxonómicamente identificada dentro del orden Botryosphaeriales se encontró dentro del top 5 de abundancia relativa en todos los tipos de muestras y significativamente más abundante en acículas y ramas con fenotipo enfermo en relación a sanas. Este estudio es la primera caracterización de la microbiota de Araucaria araucaria a través de secuenciación amplicon y la base de futuros análisis para determinar el agente causal del DFA.

Proyecto Araucaria PT2-PY2, financiado por CONAF y apoyado por Fundación Mar Adentro

112 Formation of hybrid films obtained by spray pirólisis, with antibacterial activity

Formacion de películas híbridas obtenidas por spray pirólisis, con actividad antibacteriana

Valezka Del Pilar Alcayaga3,1, Martha Hengst3,2, Sandra Fuentes. (1) Biomedico, Ciencias de la salud, Universidad De Antofagasta (2) Ciencias farmacéuticas , Ciencias , Universidad católica del norte (3) Centro de Bioingeniería y Biotecnología

Existe a nivel mundial preocupación por el peligro inminente de infecciones que son causadas por bacterias patógenas; las que proliferan fácilmente en cualquier superficie donde existe materia orgánica y humedad. El Cu posee amplias propiedades como desinfectante para eliminar bacterias, hongos y virus. Chile abarca cerca del 35% del mercado mundial; sin embargo, existe poca inversión en productos con valor agregado basado en el uso de Cu. El uso de tecnologías basada en cobre para el control de patógenos en Chile, está en una etapa de desarrollo primario. Considerando que i) la ocurrencia de microorganismos patógenos multi-resistentes a antibióticos está en aumento y que, ii) el cobre posee propiedades inigualables como biocida; en esta investigación se propuso la síntesis, caracterización, encapsulación y evaluación de propiedades químicas y fisicas de Np-Cu(0) como estrategia antimicrobiana. Para ello, las NPs fueron sintetizadas con el método de poliol y su posterior encapsulación fue realizada con una matriz polimerica hibrida. Estos polímeros naturales, fueron utilizados como recubrimiento de las Np y para formar una película biodegradable y biocompatible, con actividad antimicrobiana. Las Np-Cu(0) fueron caracterizadas por tecnicas fisico y quimicas, ademas la actvidad antimicrobiana se evaluo por medio del recuento UFC. Se confirmó que el mayor porcentaje de NPs-Cu obtenidas eran de cobre puro en estado de oxidación (0). Se realizó la encapsulación de las Np en la matriz hibrida demostrando una estabilidad a la oxidación en el tiempo (1 mes) y que esta presentaba actividad inhibitoria frente a la cepa S. aureus 25923 ATCC

Proyecto Basal CeBiB FB0001

113 Evolutive convergence of Cyanobacteria in hot springs revealed through metagenomics

Convergencia evolutiva de cianobacterias de fuentes termales revelada mediante metagenómica

Jaime Andres Alcorta1, Oscar Salgado1, Beatriz Díez2,1. (1) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica De Chile (2) Centro de Ciencia del Clima y la Resiliencia (CR)2, Universidad de Chile (Sponsored by Beatriz Eugenia Díez Moreno)

Cyanobacteria are dominant primary producers in hot springs microbial mats around the world. Since two centuries ago, by diverse methods, many species have been identified living even at the temperature limit for oxygenic photosynthesis (74 °C). Their evolutive relationships revealed that the ability to live in hot springs is polyphyletic and a derived more than an ancient feature. The genomic information is available for only several genera like Fischerella or Synechococcus, but other taxa are underrepresented or with inadequate taxonomic assignation in databases. We aim to expand the genomic landscape of these thermophilic cyanobacteria through the recovery of genomes from metagenomes, together with the implementation of a genome-based taxonomy, uncovering their genomic differences respect to the most closely related cyanobacteria that live in non-thermal environments. We analyzed 10 hot spring microbial mat metagenomes (32 – 75 °C) from which were recovered 21 cyanobacterial metagenome-assembled- genomes. These high and medium quality genomes were distributed across 8 different orders in the phylum, and 13 corresponded to new species. These genomes supported previous well-known thermophilic taxa, and one could even represent a new family. Evolutionary relationships classified many of them in the same family or genus than cyanobacteria from non-thermal environments, revealing the closeness between their genomes. Comparisons showed differences in the genome size, gene content, secondary metabolite biosynthesis clusters and CRISPR arrays when their genomes evolved and diverged from non-thermal to hot spring environments. These findings reveal strategies used by cyanobacteria to adapt and be successful in these new extreme niches.

FONDECYT regular N° 1150171 and 1190998. Doctoral fellowships CONICYT N° 21191763 and 21172022.

114 Resistant rootstock decrease damage in Limachino plant during attack of the phytopathogen Pseudomonas syringae pv. tomato

Portainjerto resistente disminuye el daño en plantas de tomate Limachino durante el ataque del fitopatogeno Pseudomonas syringae pv. tomato

Juan Felipe Alfaro1, Juan Pablo Martínez 2, Stanley Lutts 3, Michael Seeger4. (1) Departamento de Quimica, Centro de Biotecnología UTFSM, Universidad Técnica Federico Santa María (2) Instituto de Investigaciones Agropecuarias, INIA La Cruz (3) Earth and Life Institute-Agronomy (ELI-A), Université Catholique de Louvain (4) Departamento de Quimica, Universidad Técnica Federico Santa María

Pseudomonas syringae pv. tomato (Pst)is one of the most harmful bacteria in the industrial and agricultural production of tomato. This phytopathogen causes bacterial speck disease and, therefore, significant economic losses. The control the pathogen, antibiotics and highly toxic chemical compounds are generally used. The objective of this study is to evaluate the effects of the use of the tomato rootstock on the physiology and antioxidant defense mechanisms in the grafted plant challenged to Pst. Rootstocks have been widely used to produce tomatoes, contributing to a clean handling, especially in tomatoes sensitive to environmental conditions such as the Limachino tomato. This genotype is highly sensitive to environments of biotic and abiotic stress. Growth parameters and damage produced were assessed in plants. Furthermore, the plant physiology, gene expression, antioxidant metabolism in the defense mechanism were studied. The plant defense response through the antioxidant mechanism in the aerial part was determined. Rootstock increased gene expression of antioxidant metabolism (APX, CAT) and salicylic acid content in Limachino plant. On the other hand, rootstockreduced the MDA increase and bacterial growth in Limachino tomato. The data were processed through principal components analysis (PCA). At 3 days after infection, significant differences between grafted plant types were observed, where L/L plants showed higher incidence, severity and bacterial CFU than L/R plants.

115 State of knowledge of extremophile microorganisms of the high andes of Bolivia and its biotehnological and ecological applications

Estado de conocimiento de microorganismos extremófilos de los altos andes de Bolivia y sus aplicaciones biotecnológicas y ecológicas

Pablo Alfaro1, Licyel Paulas2, Daniel Villarroel3, Micaela Mendieta3, Daniel Guzmán1, Erika Fernández3. (1) Centro de Biotecnología, Facultad de Ciencias y Tecnología, Universidad Mayor de San Simón (2) Centro de Aguas y Saneamiento Ambiental, Facultad de Ciencias y Tecnología, Universidad Mayor de San Simón (3) Departamento de Biología, Facultad de Ciencias y Tecnología, Universidad Mayor de San Simón

Los Altos Andes de Bolivia poseen una gran diversidad de ambientes extremos como salares, géiseres, lagos salinos y humedales geotérmicos que proporcionan un nicho ecológico único para microorganismos que prosperan en estos ambientes hostiles. Su estudio en Bolivia se ha incrementado debido a los intereses de identificar potenciales usos en la biotecnología pero que presenta baja organización y estancamiento del conocimiento en fuentes secundarias. El objetivo de esta revisión fue compilar y sistematizar la información generada en esta zona biogeográfica hasta la fecha; trascendiendo el conocimiento bajo una revisión de tendencias. Se realizó un análisis y síntesis de fuentes bibliográficas primarias y secundarias al consultar centros de investigación locales, bibliotecas y bases de datos en- línea; donde sólo el 53% se encontró en-línea. En la revisión se registra estudios de aislamiento y descripción de 47 cepas y 13 consorcios bacterianos, 4 hongos y 11 microalgas; sin embargo, sólo el 61% están identificadas a nivel de especie. A partir de ello, se construyó una base de datos con sus respectivos perfiles de aplicaciones; siendo la producción de enzimas, biorremediación y producción de bioplásticos las mayores tendencias. Los tipos de ambientes más estudiados son lagos salinos en Potosí, y géiseres y fuentes termales en Oruro; alojando a microorganismos halófilos, termófilos y acidófilos en su mayoría. Es imprescindible mayor investigación y organización para cubrir vacíos en la investigación boliviana junto a una base unificada de fácil acceso que promueva identificación y caracterización de recursos genéticos para su próxima agrupación en bancos de conservación base.

116 Potential functional role in the supply of nutrients from bacteria associated with lichens with different types of photobionts

Rol funcional potencial en el suministro de nutrientes por parte de bacterias asociadas a líquenes con diferentes tipos de fotobiontes

Katerin Almendras1, Jaime García1, Margarita Carú1, Julieta Orlando1. (1) Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile

Los líquenes son asociaciones simbióticas bi o tripartitas entre un hongo y uno o dos compañeros fotosintéticos. En las asociaciones bipartitas, el hongo puede asociarse a un alga verde (clorolíquenes), el cual aporta productos fotosintéticos; o puede asociarse a una cianobacteria (cianolíquenes), la que además de fijar carbono, puede fijar nitrógeno. Según esto, se ha propuesto que las bacterias diazotróficas asociadas a clorolíquenes podrían suministrar nitrógeno y de esta forma sustentar parte de la nutrición del liquen. En este trabajo determinamos la estructura genética y la abundancia de bacterias fijadoras de nitrógeno en la microbiota asociada a talos y sustratos de cianolíquenes del género Peltigera y clorolíquenes del género Cladonia. Proponemos que los clorolíquenes tienen mayor diversidad de bacterias fijadoras de nitrógeno que los cianolíquenes. La estructura genética del gremio se determinó mediante TRFLP del gen nifH, mientras que la abundancia se cuantificó mediante qPCR del mismo gen. Análisis multivariados mostraron que la estructura genética del gremio asociado a los talos de ambos líquenes fue distinta a la presente en sus sustratos y a la vez fue diferente al comparar clorolíquenes y cianolíquenes. Además, la diversidad de bacterias fijadoras de nitrógeno, calculada usando el Índice de Shannon, fue mayor en clorolíquenes que en cianolíquenes. Sin embargo, la cuantificación mediante qPCR reveló que la abundancia del gen nifH fue considerablemente mayor en los talos de cianolíquenes que en los clorolíquenes, probablemente debido a la presencia del cianobionte en los primeros, por lo que se propone la cuantificación del gremio excluyendo cianobacterias

FONDECYT 1181510, CONICYT-PCHA/Doctorado Nacional/2016-21160637

117 Unveiling the worldwide uv-metaresistome: metagenomic analysis of microbiomes exposed to different UV-B regimes

Develando el uv-metaresistoma mundial: analisis metagenomico de microbiomas expuestos a diferentes regímenes de UV-B

Daniel Gonzalo Alonso-Reyes1, María Eugenia Farías2, Virginia Helena Albarracín1. (1) CISME-UNT-CONICET (2) PROIMI-CONICET

Mediante el uso de metagenómica y datos climáticos georreferenciados, este trabajo describe el impacto de la radiación UV-B sobre comunidades microbianas en términos de abundancia de genes de foto-protección y de reparación del ADN, como parte del UV metaresistoma. El set de datos consistió de diez metagenomas tomados de la base de datos del NCBI, los cuales fueron posteriormente ligados a los valores de irradiación UV-B correspondientes para el sitio y tiempo de muestreo. Nuestros resultados muestran que un aumento de la intensidad de la radiación se corresponde con un acrecentamiento de la abundancia/diversidad de los genes del UV metaresistoma, así como también una disminución de la diversidad microbiana. Se realizó una investigación de los genes de la familia fotoliasa/criptocromo (CPF) en todo el set de datos, y se observó que estos genes están presentes en los taxones dominantes de aquellas comunidades que presentan una elevada exposición a la luz. Tres clados adicionales que no estaban identificados hasta el momento han sido reportados. Así mismo, se ha reportado una presencia notable de aquellas subfamilias CPF de naturaleza criptocrómica en la mayor parte del set de datos analizado, dando cuenta del éxito evolutivo de estas proteínas y su función probablemente complementaria a las fotoliasas. En resumen, los microbiomas evolucionan y se adaptan a la presión del UV diversificando los mecanismos de resistencia y elevando el número de copias de los genes correspondientes.

PIUNT CONICET

118 Characterization of the culturable fraction of ovarian microbiota of Aedes aegypti

Caracterización de la fracción cultivable de microbiota ovárica de Aedes aegypti

Wilber Alexander Alvarado1, Susana Ochoa2, Iván D. Vélez1, Rafael J. Vivero3. (1) Programa de Estudio y Control de Enfermedades Tropicales, Sede de Investigación Universitaria (2) Facultad de Ciencias de la Salud-Biociencias, Institución Universitaria Colegio Mayor, Medellín, Colombia. (3) Grupo de Microbiodiversidad y Bioprospección, Universidad Nacional de Colombia

Aedes aegyptiis the main vector of arboviral diseases and it represent a risk factor for human populations. Mosquitoes have bacterial communities in different organs, mainly in the midgut, but to a lesser extent in reproductive organs like ovaries. Bacteria affect metabolic and physiological processes in the mosquito like blood ingestion. However, the ovarian microbiota has not been studied. The present study identified the culturable bacterial communities associated with ovaries of A. aegyptiROCK strain and evaluated their potential function during oocyte development. Adult female mosquitoes (N=45) were separated in 3 groups (n=15) with different diets, sugar solution (10%), blood and blood feed with antibiotic treatment (200 ul tetracycline). Extraction and inoculation of mosquito ovaries was carried out, the bacteria isolation, morphological characterization and antimicrobial susceptibility tests by Vitek 2. Bacterial species determination was achieved by sequence analysis of 16S rRNA gene. Higher bacterial growth was observed in the sugary feeding group 6x10³ CFU/ml in contrast to the blood feeding and antibiotic treatments groups (4.03-4.04x10³CFU/ml and 4.85-5.04x10³CFU/ml). As result, a total of 35 colonies were isolated representing 80% gram-negative and 20% gram-positive, 72% lactose-negative and 11% lactose-positive. Seventeen isolates were selected to the identification by 16S rRNA. Ovarian microbiota during sugar solution feeding increases in its bacterial load, with respect to the treatment with blood feeding, in which microbiota can reduce its richness and be more specific. The isolates will be further investigated as a strategy of biological control and provide knowledge about their influence on reproduction.

Programa de Estudio y Control de Enfermedades Tropicales (PECET)

119 Polyhydroxyalkanoates production from low-cost carbon sources by Paraburkholderia xenovorans LB400 and Halomonas sp. ASL9

Producción de polihidroxialcanoatos por Paraburkholderia xenovorans LB400 y Halomonas sp. ASL9 a partir de fuentes de carbono de bajo costo

Natalia Sofía Alvarez-Santullano1, Pamela Villegas1, Ángela González1, Matt Woolery4, Pablo Alviz-Gazitúa1, Dinka Mandakovic2,3, Alexis Gaete2,3, Mauricio González2,3, Michael Seeger1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química, Universidad Técnica Federico Santa María (2) FONDAP Center for Genome Regulation , Universidad de Chile (3) INTA, Universidad de Chile (4) Center of Nanotechnology and Systems Biology, Universidad Técnica Federico Santa María

Polyhydroxyalkanoates (PHAs) are polyesters that are synthesized by diverse bacteria and accumulated as cytoplasmic granules under unbalance nutrient conditions. PHAs have physicochemical properties similar to conventional plastics (e.g., polypropylene) that allow them to be used as biodegradable and biocompatible thermoplastics. The use of low-cost carbon source has been studied as an alternative to reduce the production cost. The aim of this study is to characterize the production of PHAs by Paraburkholderia xenovorans LB400 and Halomonas sp. ALS9 from industrial by-product such as waste glycerol and agro-industrial residues. The whole genome of Halomonas sp. ASL9, isolated from Lejia Lake, Chile, was sequenced. The PHA anabolic pathways genes were identified. Nile red staining method was used as screening for PHAs production from diverse carbon sources. Bacterial growth and PHB production were monitored during 72 h. Cells were harvests and the pellet were freeze-dried and subjected to propanolysis. Propylesters obtained from propanolysis were analysed by GC-MS for identification and quantification of PHAs. During growth on glycerol, ALS9 and LB400 cell accumulated PHB up to 65% and 30% cell dry weight, respectively. Strain LB400 reached up 5 g L-1 of cell dry weight and accumulated up 17% and 20% cell dry weight when growing on orange peel and waste tomato, respectively. These results suggest that both strains can be useful for industrial production of PHA from low-cost substrates.

Proyecto FONDECYT 1151174 (MS), Proyecto Anillo GAMBIO ACT172128 (MS), USM grants.

120 CyDiv, a new protein factor in cyanobacterial cell division

CyDiv, un nuevo factor de división celular en cianobacterias

Derly Andrade Molina1, Javier Chichon2, Jose María Valpuesta2, Miguel Vicente3, Mónica Vásquez4. (1) Medicina, Ciencias médicas, Universidad Espíritu Santo. Samborondón, Ecuador (2) Estructura de Macromoléculas, Centro Nacional de Biotecnología: Madrid, España (3) Biotecnología microbiana, Centro Nacional de Biotecnología: Madrid, España (4) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica de Chile

Cyanobacteria are oxygenic photosynthetic microorganism, it cell walls and cell division proteins has properties that are a combination of both gram-positive and gram-negative bacteria. Previous studies carried out in our laboratory determined a common gene in all filamentous cyanobacteria (cyDiv), this is essential for a proper cell division. We analyzed phenotypic variations under different transcription levels controlled by copper-inducible promoter and, determined a morphological effect by CryoEM Tomography of X-ray. Furthermore, the association of CyDiv was evaluated with other protein involved in cell division by BIFc. Integral results from controlled transcription, cellular localization and protein interaction suggest that CyDiv is essential for cell division, its alteration in Anabaena sp. PCC7120 will lead to a miss Z- ring positioning, increasing the size of lipid bodies, cell wall damage, and finally triggering cell lysis. The confirmation of the critical role of CyDiv due to its interaction with elements of the divisome in filamentous cyanobacteria was confirmed by BIFc.By the use of Immunofluorescence microscopy with polyclonal antibodies, determined that CyDiv and FtsQ had a subcellular location particularly similar. These proteins are localized from cell pole to the middle of the cell depending of the division stage. Biochemical characterization of CyDiv determines that the periplasmic region is represented by a-Helix, confirming that this protein has similar topology of the protein from E. coli (FtsB). CyDiv is essential for cell division in Cyanobacteria because it interact directly with divisome proteins, being able to be FtsB homologous protein in cyanobacteria.

Fondecyt grants #1131037, 1161232, Fellowships for Graduate Student of Chilean Government # 21150983.

121 Microbial quality of São Paulo state coast (Brazil): a comparison between water and sediment

Calidad microbiana de la costa del Estado de Sao Paulo (Brasil): Una comparación entre agua y sedimento

Vanessa Da Costa Andrade1,2, Bruna Del Busso Zampieri1,2, Roberta Merguizo1, Ana Júlia Fernandes Cardoso De Oliveira1. (1) Marine and Environmental Laboratory (Micromar), Bioscience Institute, São Paulo State University - UNESP (São Vicente) (2) Biochemestry and Microbiology, Bioscience Institute, São Paulo State University - UNESP (Rio Claro)

Coastal areas concentrate most of the world´s population, and have a great importance to economy and tourism. But those areas are not always followed by sanitation. The lack of proper sanitation leads to the increase of discharge of effluents and contaminants, including pathogenic bacteria. Escherichia coli is the most common microbial indicator for water quality, but in marine areas, Enterococcus sp. represents a better indicator. The present study aimed to evaluate and compare densities of E. coli and Enterococcus sp. in water and sediment samples. Three beaches along São Paulo coast were analyzed: Port of Santos (Santos/SP), Araça Bay (São Sebastião/SP) and Fazenda Beach (Ubatuba/SP). Santos and São Sebastião are areas with a medium-high anthropogenic impact. On the other hand, Fazenda Beach is a well-preserved area and without anthropic impact. Water and sediment samples were collected at 5 points in each beach, during summer and winter. The Membrane Filter Technique was performed, with mTEC Agar (Escherichia coli) and mEnterococcus Agar (Enterococcus sp.). Densities were expressed in colony forming unit per milliliter (CFU mL-1) and CFU per gram (CFU g-1), for water and sediment, respectively. The results showed that Port of Santos, presents higher densities when compared to other areas, and above Brazilian National Council of Environment (CONAMA) standards for water. Densities in sediment samples were higher than in water samples at all beaches. The present results show the importance of creating standards and public policies for sediment, especially due the serious risk to public health.

CAPES

122 Characterization of carbapenem-resistant plasmids in ST11 Klebsiella pneumoniae during a nosocomial outbreak with environmental dissemination

Caracterización de plásmidos resistentes a carbapenem en Klebsiella pneumoniae ST11 durante un brote epidémico hospitalario con diseminación en ambientes urbanos

Verónica Antelo2,1, Cecilia Salazar2,1, Matías Giménez3,1, Gregorio Iraola 4,1,5. (1) Laboratorio de Genómica Microbiana, Institut Pasteur de Montevideo (2) Proyecto “Centro de Metagenómica”, Institut Pasteur Montevideo (3) Laboratorio de Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable (4) Unidad de Bioinformática, Institut Pasteur Montevideo (5) Centro de Biología Integrativa, Universidad Mayor

Carbapenemase-producing Klebsiella pneumoniae (KPC) is among the most life-threatening bacteria due to its capacity of acquiring extensive antimicrobial resistance.

In this study we used a combination of short and long-read sequencing technologies, metagenomics and phenotyping to characterize a nosocomial outbreak caused by multi-drug resistant KPC in Montevideo, Uruguay, 2016-2017. All were classical strains genotyped as ST11, ICEKp3 and ybt 9.

We generated draft genome sequences for 16 outbreak strains and complemented this with Oxford Nanopore long reads to close KPC genomes. This allowed the discovery of a novel megaplasmid (>150 kb.) encoding bla-KPC and bla-TEM genes. Other genes conferring resistance to aminoglycosides (AAC(6´)-Ib7), sulfonamides (sul1), quinolones (QnrB20) and trimethoprim (dfrA25) were also detected. The dfrA25 gene is carried on a class 1 integron. In addition, genes essential for conjugation processes were identified. This was confirmedin vitro, as the plasmid was transferred by conjugation from its original host to E. coli DH5α. Finally, by reconstructing metagenome-assembled genomes from urban sewage water samples from Montevideo, we were able to recover exactly the same K. pneumoniae ST11 chromosome and the full KPC megaplasmid. These results indicate that outbreak-causing strains are circulating or being delivered into the urban environment, increasing human exposure and potential transmission.

Our study represents an integrative analysis of a nosocomial outbreak, revealing previously unseen characteristics of KPC circulating in our country and the region, and confirming the mobilization and dissemination potential of KPC plasmids.

Agencia Nacional de Investigación e Innovación (ANII)

123 Propolis as a strategy to improve the health of bees: preliminary results

Una primera aproximación al uso de propóleos como estrategia para mejorar la salud de las abejas

Guillermo Añon1, Daniela Arredondo 1, Pablo Zunino1, Karina Antúnez1. (1) Departamento de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE), Montevideo, Uruguay

Las abejas melíferas son los principales agentes polinizadores de plantas silvestres y cultivos comerciales, cumpliendo así una función esencial para el mantenimiento de los ecosistemas naturales así como la producción agrícola. Durante los últimos años se han observado importantes pérdidas de colmenas alrededor del mundo, siendo la presencia de plagas y patógenos, una de las principales causas. La aplicación de químicos para su prevención o tratamiento puede traer severas consecuencias, como la aparición de organismos resistentes y afectar la calidad de la miel. El objetivo de este trabajo fue realizar un ensayo preliminar para evaluar el uso del extracto Etanólico de propóleos (EEP), como estrategia saludable para disminuir la infección por patógenos. Con este fin se empleó un modelo controlado de cría de abejas en el laboratorio. Se evaluó la toxicidad del EEP para las abejas en diferentes concentraciones (0,5; 1 y 2%), y frecuencias de aplicación. Posteriormente se evaluó el efecto de su administración sobre el número de esporas del microsporidio patógeno Nosema ceranae, en abejas infectadas artificialmente. El EEP en las dosis 0,5 % y 1% no resultó tóxico para las abejas; y logró disminuir significativamente la infección por el microsporidio (13 días post- infección: control sin propóleos vs EEP dosis 0,5% MW Test p=0,04; control sin propóleos vs EEP dosis 1% MW Test p=0,008). Estos resultados nos alientan a continuar trabajando en esta línea. Próximamente se repetirá el ensayo con el fin de evaluar el efecto del EEP en la comunidad microbiana intestinal, así como en la inmunidad de la abeja.

Este proyecto fue financiado por la Agencia Nacional de Investigación e Innovación (ANII), FMV 1 2017 2 135942

124 Plasticity of hydrocarbon biosynthetic pathways in Cyanobacteria

Plasticidad de vías biosintéticas de hidrocarburos en Cyanobacteria

Gladys A. Apaza-Castillo1, Bruno C. E. Souza1, Diego M. Riano-Pachon2, Marli F. Fiore1. (1) Cellular and Molecular Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo (2) Computational, Evolutionary and Systems Biology Laboratory, Center for Nuclear Energy in Agriculture, University of São Paulo (Sponsored by Coordenação De Aperfeiçoamento De Pessoal De Nível Superior - Brasil (CAPES) And The National Council For Scientific And Technological Development (CNPq))

Cyanobacteria are photosynthetic oxygenic bacteria that belong to a restricted group capable of synthesize long- chain hydrocarbons from fatty acids. This feature has been associated to flexibility of the cytoplasmic membrane due to the accumulation of hydrocarbons. Currently, cyanobacteria biomass is being applied for biotechnological purposes as biofuels and the biosynthetic mechanism of this natural process hit a model for genetic engineering. These microorganisms can synthesize hydrocarbons through two pathways: synthesis of terminal alkane by acyl-ACP reductase (Aar) plus aldehyde deformylating oxygenase (Ado) enzymes and production of terminal alkene by olefin synthase (Ols). Cyanobacterial genomes encoding Aar/Ado or Ols pathways have been reported, but never both together in the same taxon. However, a recent study based on GC-MS analyzes showed that the strain Oxynema sp. CENA135 synthesizes both types of hydrocarbons. Here, we sequenced the genome of strain CENA135 in order to identify the genes coding for the enzymes involved in hydrocarbon synthesis. Total genomicDNA was extracted from unicyanobacterial culture using the AllPrep DNA/RNA Kit and then subjected to construct an 8-kb mate-pair library and sequencing on the Illumina HiSeq2500 platform. The reads were pre-processed with PEAR and PRINSEQ, high quality reads were then assembled with SPAdes. Functional annotation was performed with RAST server, and the search for hydrocarbon biosynthetic pathways were submitted to antiSMASH, NAPDOS and BLAST analyses. The results of the hydrocarbons biosynthetic pathways found in the Oxynema sp. CENA135 genome are discussed in comparison to those identified in the cyanobacterial genomes available in GenBank.

Keywords: genome, biofuel Acknowledgments: This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001. We also thank CNPq (433166/2018-5) for funding the research project.

125 Effect assessment of pesticide residual dose on physiological conditions and microbiome structure of Apis mellifera larvae

Evaluación del efecto de una dosis residual de un pesticida sobre las condiciones fisiológicas y la estructura del microbioma de larvas de Apis mellifera

María Catalina Aranda1, Luis Guzmán2, Lida Marcela Franco3, Cristian Molina 2, Andrea Silva1,2. (1) Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias , Universidad Austral de Chile (2) AUSTRAL-omics, Vicerrectoría de Investigación, Desarrollo y Creación Artística, Universidad Austral de Chile (3) Programa de Biología Ambiental, Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Colombia

Uno de los factores involucrados en las causas de la crisis de polinizadores es la persistencia de insecticidas neonicotinoides en el ambiente a bajas concentraciones que producen en ellos una serie de efectos subletales, estando particularmente bien estudiados en la abeja de la miel (Apis mellifera). La evidencia muestra que estos compuestos alteran la fisiología, el comportamiento y en último término la sobrevivencia de las abejas. Adicionalmente, podrían afectar a la comunidad de microorganismos simbiontes (microbioma) del organismo, a través de alteraciones fisiológicas que alteran el ambiente en el que se desarrolla dicho microbioma. Dado que el microbioma es un elemento integral de la salud de la abeja, el objetivo del presente estudio es evaluar los cambios fisiológicos en A. mellifera producto de la exposición a dosis residuales de un neonicotinoide y determinar las alteraciones en el establecimiento del microbioma en sus larvas. El diseño experimental consta de 10 colmenas de abejas de miel que fueron sometidas a dos tratamientos: Colmenas alimentadas con jarabe de miel con una dosis subletal del neonicotinoide Imidacloprid; y colmenas alimentadas con tratamiento control sin insecticida. Se evaluó la fisiología de larvas mediante masa corporal y tasa metabólica. Además, mediante secuenciación masiva del gen rRNA 16S de larvas, se caracterizó la estructura de las comunidades bacterianas del microbioma de ambos tratamientos. Los resultados preliminares arrojan que los individuos expuestos a neonicotinoide presentan, aproximadamente, 10% mayor masa larval y 20% menor tasa metabólica. Los análisis bioinformáticos del microbioma larval están en proceso de elaboración.

Proyecto 18-545-INT. Universidad de Ibagué

126 Microbial ecology as didactic tool: Educational experience in Los Ríos

Ecología microbiana como herramienta didáctica: Experiencia educativa en Los Ríos

María Catalina Aranda1, Lavinia Armasu2. (1) Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias , Universidad Austral de Chile (2) ALTA UACh, Universidad Austral de Chile

Según la encuesta nacional del medio ambiente, en Chile, el 88% de las y los encuestados considera que el cambio climático es relevante y producido por los humanos. Además, un 96% considera que emprender acciones para cuidar el medio ambiente es un deber moral. Sin embargo, surge la pregunta, ¿cómo aplicamos en nuestro quehacer cotidiano esta creciente conciencia ambiental? Según cifras de la calidad de la educación chilena, solo un 6% de las y los estudiantes es capaz de comprender y aplicar conceptos sobre procesos ambientales globales abstractos. Es en este contexto que es necesario que las y los estudiantes tengan entendimiento de la forma en que las acciones humanas impactan en los mencionados problemas a través de metodologías alternativas. El presente trabajo propone utilizar el estudio de la ecología microbiana como herramienta para comprender los procesos ecosistémicos globales abstractos desde una perspectiva microscópica y práctica. La experiencia educativa se desarrolló en el marco de la escuela de talentos ALTA UACh (Región de los Ríos). Utilizando la metodología didáctica de aprendizaje por proyectos mediante situaciones problemáticas, las y los estudiantes fueron activos constructores de sus conocimientos realizando investigaciones grupales y actividades prácticas. Las actividades consistieron en salidas a terrenoen busca de muestras de agua y su observación al microscopio junto con la identificación de funciones para finalmente contextualizar los hallazgos a nivel ecosistémico. Los resultados de las investigaciones sobre ciclos biogeoquímicos y diversidad microbiana fueron comunicados en una muestra al final del semestre mediante herramientas literarias y/o orales.

ALTA UACh

127 Characterization of microbial metabolic associations in marine biofilms associated with biocorrosion and effect on the settlement of macroalgae spores

Caracterización de asociaciones metabólicas microbianas en biopeliculas marinas asociadas a biocorrosión y su efecto en el asentamiento de esporas de macroalgas

Camila Paulina Aravena1, Rodrigo De La Iglesia1, Leslie Daille1, Ignacio Vargas2. (1) Laboratorio Microbiología Marina, Ciencias Biológicas, Pontificia Universidad Católica De Chile (2) Laboratorio de Biotecnología y Microbiología Ambiental, Ingeniería, Pontificia Universidad Católica De Chile

Microbial biofilms are part of marine environments, and can cause material deterioration through of metabolic coupling. Also, they cause bioaccumulation of macroorganisms, through settlement of macroalgaes spores and invertebrates larvaes. The objective of research was to characterize the metabolic coupling between bacteria and microalgae in marine biocorrosive biofilms and if the presence of these produce effects on release and settlement of spores of Acrochaetium sp.

The identification of microbial communities was carried out through the SSU rRNA gene massive sequencing and Sanger sequencing of 18S rRNA gene genomic libraries, from previous biocorrosion experiment in coastal environments. Metabolic coupling was characterized by metabolic predictions of the bacterial community through PICRUSt. Finally, the biofilm effect on the release and settlement of Acrochaetium sp. spores was evaluated by incubations in aquariums, flow cytometry and epifluorescence microscopy.

Results indicate dynamic changes in bacteria abundance and eukaryotic communities in the biofilm and an accurate identification of the photosynthetic organisms present. Metabolic inferences identified the main functional pathways in the biofilm: transporters, two-component regulatory system and exopolysaccharide production. Energetic functions, such as nitrogen and sulfur metabolism, suggests competition and biocorrosion relationships, respectively. Metabolic coupling was evidenced in the vitamins production, secondary metabolites, amino acids, photosynthetic activity and respiration. Finally, it was determined that the microbial biofilm, although capable of producing a greater quantity ofAcrochaetium sp. spores, generates a development reduction of these on the biofilm. This could imply an antifouling effect of some microorganisms in the biofilm that doesn’t favor the settlement of some macro-organisms.

Marine Research and Innovation Center (MERIC)

128 Response of ammonium-oxidazing archaea (AOA) and bacteria (AOB) in agricultural soils to irrigation with greywater and filtered (sand and vermifilter)

Respuesta de arqueas (AOA) y bacterias (AOB) amonio-oxidantes en suelos de cultivo al riego con agua gris y tratada (filtro arena y vermifiltro)

Rocío Melissa Aravena1, Hermann Peña 1, Maykol Rojas 1, Cecilia Rivera 2, Veronica Molina1. (1) Observatorio de ecologia microbiana, Facultad de ciencias naturales y exactas , Universidad de Playa Ancha (2) Departamento de ciencias , Facultad de ciencias naturales y exactas , Universidad de Playa Ancha (Sponsored by Verónica Andrea Molina Trincado)

El crecimiento de vegetales depende de la biodisponibilidad de nitrógeno y del microbioma edáfico. En el reciclaje de nitrógeno participan comunidades amonio-oxidantes arqueanas (AOA) y bacterianas (AOB) quienes realizan la primera etapa de la nitrificación, cuya contribución relativa (AOA:AOB) responde a las condiciones fisicoquímicas del suelo. Se determinó la estructura y composición comunitaria bacteriana en un suelo humífero regado durante 7 semanas con: agua gris (GW), agua gris tratada en filtro de arena y vermifiltro (SFW, VFW), y agua potable (DW) como control, en comparación con las condiciones iniciales del suelo. Se determinaron parámetros fisicoquímicos asociados (n=17) a la calidad del agua de riego estándar y del suelo (pH, conductividad y materia orgánica total). La abundancia de comunidades AOA y AOB y de bacterias totales se cuantificó mediante qPCR (gen funcional amoA y 16S rRNA, respectivamente) y secuenciación (iTag-16S rDNA). El agua gris filtrada por VFW presentó un menor pH y conductividad, y un mayor contenido de nutrientes en comparación a GW y SFW. Sin embargo, VFW cumplió únicamente con 58% de los parámetros analizados con respecto a la norma ch. 1333. La razón AOA: AOB disminuyó en todos los tratamientos excepto en VFW, relacionado con el aumento de la conductividad del suelo (Spearman r=-0,9, p=0.037). Los resultados de secuenciación muestran un enriquecimiento de Planctomycetes, Gammaproteobacteria, Nitrospirae, Chlorofexi en suelos regados con aguas grises en comparación a DW. En total nuestros resultados indican que la irrigación altera el microbioma edáfico, incluyendo grupos funcionales del ciclo del nitrógeno.

FONDECYT financiaminto regular 1171324

129 Identification of genes conferring tolerance to furans and phenolics by functional selection of a genomic library based in tolerant bacterial isolates from polluted sites

Identificación de genes que confieren tolerancia a furanos y compuestos fenólicos mediante la selección funcional de una biblioteca genómica basada en aislamientos bacterianos tolerantes de sitios contaminados

Marcelo Araya1, Mauricio Guajardo-Parra2,1, Carla Gárate-Castro1, Danilo Pérez-Pantoja1. (1) de industria alimentaria y biotecnología , Facultad de ciencias naturales matemática y del medio ambiente, Universidad Tecnológica Metropolitana (2) Universidad Tecnológica de Chile Inacap

Lignocellulosic wastes are typically considered as one of the most promising feedstocks to generate a variety of renewable fuels and value-added chemicals. Nevertheless, during hydrolysis treatment of biomass several by-products are generated that are collectively termed lignocellulose-derived inhibitors (LDIs). They have a strong negative effect over biofuels production by affecting physiology of the fermentative microorganisms at different levels. A promising solution addressing LDIs toxicity is development of more robust fermentative microorganisms by increasing their tolerance. In this study we constructed a plurigenomic library, including genomes of multiple bacterial strains isolated by their high LDIs tolerance, and we used it for functional screening of tolerance genes. Tolerant microorganisms were isolated from three different environments: i) sludge treatment of pulp mill effluents, ii) olive oil wastes disposal sites, and iii) bulk soils from university campus. In total 41 tolerant microorganisms were isolated but only five genomes were selected for library construction including members ofEnterococcus, Lactobacillus, Pseudomonas and Brevibacterium genera as revealed by 16S rRNA identification. TheE. coli DH10B strain was used as library host and functional selection was performed in presence of inhibitory concentrations of furans or phenolic compounds that are recognized as conspicuous LDIs. The tested inhibitors were individually assayed and include furfural, 5-hidroximetilfurfural, vanillin, guaiacol, syryngaldehyde and 4-hydroxybenzaldehyde. Several tolerant clones were selected and their phenotype was confirmed by microdrop assay for insert sequencing. The genes putatively conferring tolerance were mostly related to DNA repair suggesting the key role of nucleic acids as main target of LDIs toxicity.

ACKNOWLEDGMENTS: This study was supported by FONDECYT Grant N° 1161750 and CONICYT Research Ring N° ACT172128 from Chilean Government.

130 Ménage à trois: Coexistence between a wild-type bacterium, a lysogenic bacterium and a temperate bacteriophage of V. anguillarum

Ménage à trois: Co-existencia entre una bacteria silvestre, una bacteria lisógena y un bacteriófago temperado de V. anguillarum

Manuel Arce1, Simone Latz1, Roberto Bastias1. (1) Laboratorio de Microbiologia, Instituto de Biologia , Pontificia Universidad Católica de Valparaíso

Los bacteriófagos temperados son capaces de persistir insertandose en el genoma del hospedero, formando bacterias lisógenas. En el ambiente coexisten bacterias lisógenas, bacteriófagos y también bacterias no lisógenas, siendo interesante estudiar las dinámicas poblacionales entre estos microorganismos para entender su ecología. Este trabajo evalúa, a través de co-cultivos y PCR específicos, la coexistencia entre la cepa PF4 de V. anguillarum, el bacteriófago temperado Valp1 específico para esta bacteria, y la cepa P1.1 de V. anguillarum, correspondiente a la cepa PF4 lisogenizada por Valp1. Los resultados mostraron que la cepa P1.1 domina el cultivo manteniéndose en una proporción cercana al 90%. A pesar de esto, la cepa PF4 nunca es totalmente desplazada del cultivo, incluso luego de 10 horas. La cepa PF4 se mantiene en las mismas proporciones incluso luego de 5 sub-cultivos seriados. Mientras que, el fago Valp1 alcanza una concentración cercana a 10E8 en el co-cultivo, que se mantiene a través de lo sub-cultivos. Finalmente se observó que parte de las cepas de PF4 presentes en el co-cultivo era resistente a Valp1, cuya proporción llegó al 100% al final del cultivo, y se mantuvo en los sub-cultivos seriados. Interesantemente la resistencia al fago se perdió luego de 10 sub-cultivos seriados en ausencia del fago. Estos resultados sugieren la existencia de un mecanismo de resistencia en PF4 que permite la co-existencia entre estas tres poblaciones. En este sentido será interesante evaluar en un futuro los mecanismos involucrados en este equilibrio y su estabilidad frente a distintos factores ambientales

131 Mining waste 16S rRNA gene sequencing for detection of potential acid drainage risk

Secuenciación del gen 16S ARNr de residuos mineros para detectar potencial riesgo de drenaje ácido

Montserrat Arciénaga1, Francisco L. Massello1, Josefina Plaza Cazón1, María Sofía Urbieta1, Edgardo Donati1. (1) CINDEFI, Facultad de Ciencias Exactas, Universidad Nacional de La Plata

Los residuos mineros que contienen sulfuros representan un gran riesgo ambiental debido a que su oxidación puede generar drenaje ácido de minas (DAM); este proceso se intensifica significativamente por acción de ciertos microorganismos. La Planta de tratamiento La Poma es un antiguo laboreo de Pb y Ag ubicado en la provincia de Salta cuyas escombreras se encuentran cercanas al cauce del río Tajamar que influye posteriormente sobre distintos ecosistemas y cuyas aguas son usadas en agricultura y para consumo en general. En muestras del dique de cola y del sedimento del río se realizaron extracciones de ADN genómico para analizar la composición microbiana por secuenciación metagenómica de las regiones hipervariables V3 y V4 del gen 16S ARNr (Ilumina MiSeq 2x300 PE). Las secuencias obtenidas fueron analizadas mediante el paquete bioinformático MOTHUR. Los filos más abundantes fueron Proteobacteria, Actinobacteria, Firmicutes y Bacteriodetes. Algunas de las secuencias se correspondieron con géneros como Leptospirillum, Acidithiobacillus, Sulfobacillus, Ferroplasma y Acidianus, mayoritariamente oxidantes de hierro y azufre, reconocidos por su capacidad para generar DAM. También se identificaron otros géneros recientemente descriptos en aislamientos realizados en entornos mineros como Geothrix, Ferrovum, Ferrithrix, Sulfuriferula, Metallibacterium y Acidithrix, que también son oxidantes de hierro y/o azufre. La presencia de estos microorganismos fue confirmada por el aislamiento posterior de algunas especies y por su acción oxidante sobre el residuo. Esto implica un serio riesgo de generación temprana de DAM en estos pasivos ambientales.

ANPCyT, PICT-2016-2535 y PICT-2015-0463

132 Removal of calcium and magnesium from seawater in a fluidized bed bioreactor with immobilized cells of Bacillus subtilisLN8B

Eliminación de calcio y magnesio desde agua de mar en un biorreactor de lecho fluidizado con células inmovilizadas de Bacillus subtilis LN8B

Dayana Arias2, Mariella Rivas1, Luis A Cisternas2, Grecia Villca2. (1) Biotecnología, Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (2) Ingeniería Química y Procesamiento de Minerales, Ingeniería, Universidad de Antofagasta

Los iones Ca2+ (~400 ppm) y Mg2+ (~1400 ppm) presentes en el agua de mar (AM) generan inconvenientes en los procesos de flotación y sedimentación cuando se usa AM sin desalar en los procesos mineros. Esta investigación estudió la eliminación de estos iones en un biorreactor de lecho fluidizado (BLF) con la cepa ureolítica halotolerante Bacillus subtilis LN8B. Se utilizó alcohol polivinílico (PVA) como matriz de inmovilización celular, en tanto el modo de operación a la fecha se ha realizado en discontinuo con un promedio de oxígeno disuelto (DO) del 104%, un pH de 9.08, una concentración de urea inicial de 30 g/L y una temperatura diaria promedio de ~ 27°C. Bajo estas condiciones, la tasa de eliminación alcanzó ~ 98.75% (5 ppm) a los 3 días para Ca2+ y ~75% a los 5 días para Mg2+ (350 ppm). Con relación a la reutilización de la matriz de PVA, esta alcanzó 6 operaciones bajo las mismas condiciones con similares tasas de remoción. La calidad del AM del BLF fue evaluada con ensayos de sedimentación con relaves y comparada con AM desalada (AMD) y sin desalar (AMS). La velocidad de sedimentación del agua generada por el BLF (6,25 m/h) generó los mejores resultados, con relación a la velocidad de sedimentación de AMD (5,23 m/h) y AMS (2,31 m/h). Finalmente, este estudio refuerza la aplicación de la biomineralización mediada por bacterias ureolíticas halotolerantes como herramienta biotecnológica para mejorar la calidad del AM para procesos mineros.

CONICYT PIA ACM170005 RELAVES Y AGUA DE MAR

133 Evaluation of plant growth-promoting (PGP) traits of selected consortia from culturable rhizobacteria associated with flowering desert phenomenon

Evaluación de características promotoras del crecimiento vegetal (PGP) de consorcios rizobacterianos seleccionados desde el Desierto Florido

Marcia Carolina Astorga1, Susett Gonzalez G.1, Milko A. Jorquera 2. (1) Doctorate Program of Science in Natural Resources, Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera (2) Scientific and Biotechnological Bioresources Nucleus (BIOREN), Applied Microbial Ecology Laboratory, Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera

The Atacama Desert considered the driest non-polar place in the world, is sporadically filled with life and color in a phenomenon called the ‘flowering desert’ (FD). Studies have described the wide diversity of bacteria associated with native plants in the Atacama Desert, including the occurrence of potential plant growth‒promoting (PGP) bacteria. The goal of this work was to evaluate some PGP-traits in selected culturable rhizobacteria during pre-flowering (PF) and full-flowering (FF) of Cisthante sp., one of the representative native plant during FD and analyze their potential use as plant growth promoting rhizobacteria. Rhizosphere soil samples were collected from Cisthante sp. mantles during PF and FF. Bacterial isolates were identified and P-solubilization, potential N fixation, tryptophan- dependent auxins production, 1-aminocyclopropane-1-carboxylate deaminase and exopolysaccharides production were assayed. After the compatibility test, three rhizobacterial consortia were assembled and the PGP-traits individually tested. All consortia presented the aforementioned traits. Even more, some of them shown a synergistic behaviour increased some of the PGP-traits activities. In preliminary assays tomato plants (CalAce variety) were used as model, the consortia were able to diminish the amount of days from sowing to germination, compared to uninoculated control. In addition, seedlings under water shortage stress for several hours were able to thrive to this stress and survive to more than 72 h of drought when rhizobacterial consortia were applied. Considering these preliminary results, it is possible to assume the potential use of rhizobacteria from the Flowering Desert as an input in agriculture to prevent damage by drought or high temperatures.

Fondecyt project N° 1160302 and Conicyt Scholarship N° 21151002

134 Insights on the longest red tide ever recorded to date in northern Chile: monitoring and accessing microorganisms with potential mitigation activity

Evidencias en la marea roja más larga reportada en el norte de Chile: monitoreando y accediendo a microorganismos con posible actividad mitigadora

Vladimir Avalos1, Henry Cameron1, Stephanie Barría1, Leonardo Gonzalez1, Camila Sayes1, Victor Sánchez1, Carlos Riquelme1. (1) Centro de Bioinnovación, Facultad Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta

Las mareas rojas, conocidas también como floración de algas dañinas (FANs), corresponden a la coloración de cuerpos de agua, manifestándose usualmente en aguas de costa, pero a menudo naciendo en mar abierto. Esto es debido a un rápido crecimiento de microalgas hasta que puntos densos coloreados son visibles al ojo humano. Este evento ha sido observado anteriormente en las costas de Chile, sin embargo, esta es la primera vez que alcanza aproximadamente 1,500 km (aproximadamente 70,000 km2), inclusive llegando al sur de Perú y durando por lo menos 5 meses, siendo Prorocentrum micans el principal dinoflagelado de esta floración. Como uno de los variados intentos para mitigar o reducir las floraciones, se realizó un ensayo de antagonismo con microorganismos previamente aislados desde la costa local, el cual consisitió en exponer el principal microorganismo de la marea roja local frente a estos diferentes aislados utilizandolos como mitigadores naturales. Resultados preliminares muestran disminución de las concentraciones de marea roja enfrentados a nuestros organismos objetivo Oxyrrhis marina y Phaeodactylum tricornutum (disminución de hasta la mitad o mantenimiento de concentración celular, respectivamente). Mediante Secuenciación masiva – Plataforma Illumina, fue posible elucidar la diversidad inicial de la comunidad fitoplanctónica y bacteriana de los ensayos de antagonismo, y luego seguir los diferentes cambios a lo largo de los días experimentales. Además, se puede observar una alta abundancia en Vibrio spp. y Thalassobius spp. en cuanto a bacterias, y una alta diversificación con leves niveles de mitigación en algunas muestras.

PROYECTO FONDEF IT17F10001

135 Effects of saponins of Quillaja saponaria Molina on hydrocarbons bioremediation of polluted marine water

Efectos de saponinas de Quillaja saponaria Molina en la biorremediación de hidrocarburos en agua marina contaminada

Bárbara Barra-Sanhueza1, Lisette Hernández1, Roberto Durán1, Myriam González1, Michael Seeger1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química, Universidad Técnica Federico Santa María

Combined bioremediation strategies are useful for the clean-up of petroleum hydrocarbon-polluted ecosystems. Hydrocarbons low bioavailability limits bioremediation in marine environments. Saponins are natural biosurfactants synthesized by specific plant species. Saponins and hydrocarbon-degrading microorganisms may increase the efficiency of hydrocarbon degradation. In this study, the effects of biostimulation withQuillaja saponaria saponins and bioaugmentation with a bacterial consortium on the hydrocarbons degradation and the bacterial community dynamics in contaminated marine water at micro- and mesocosm scales were studied. A hydrocarbonoclastic consortium was formed by Pseudarthrobacter sp. LD52b, Micrococcus sp. LD135, Alcaligenes aquatilis QD168 and Dietzia sp. LD181 isolated from crude oil-polluted marine sediments of Central Chile. The microcosms systems contained 1.5 L Bushnell-Haas minimum medium supplemented with artificial seawater and 1% diesel. Samples were taken for hydrocarbon analysis and CFU mL-1 were counted. The biostimulated-bioaugmented system showed 90% degradation of hydrocarbons (C10-C25), reaching 3.5 × 109 CFU mL-1. The mesocosm scale assay was carried out using 15 L seawater systems from Valparaíso Bay spiked with 1% diesel. Hydrocarbons degradation was evaluated by GCFID. Increased biodegradation was observed after biostimulation and bioaugmentation. Community structure and dynamics were evaluated by 16S rRNA gene sequencing by MiSeq Illumina. An increase of the Alcaligenes genus from 9 to 84% after inoculation was observed, decreasing at the last week to 27%. Alcanivorax genus from native community increased from 0.5 to 37%. Biostimulation with saponins increased hydrocarbon bioavailability, favoring their degradation.

Becas doctorado Nacional CONICYT 2013-21130742 (BBS), Beca de Gastos Operacionales CONICYT 2013-21130742 (BBS), Beca magíster Nacional CONICYT 2016-22162307 (RD), Proyecto FONDECYT 1151174 (MS), Proyecto Anillo GAMBIO ACT172128 (MS) grants

136 Is fungal-endophytes functional symbiosis necessary in stress-tolerant crops?

¿Es la simbiosis funcional de hongos endófitos necesaria en la tolerancia a estrés de cultivos?

Andrea Barrera2, Patricio Ramos1,2, Ian S Acuña-Rodriguez 2, Marco A Molina-Montenegro 2,3. (1) Núcleo Científico Multidiciplinario-DI, Universidad de Talca (2) Instituto de Ciencias Biológicas, Universidad De Talca (3) Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Universidad Católica del Norte (Sponsored by FONDECYT # 1181034)

Because of climate change, soil salinization is today among the top three threats for global food security. The management of the plant root-microbial endophytes has arisen as an alternative due to their proven role in the performance of multiple plant-hosts. Nevertheless, as this management frequently involve the generation of a new plant-endophyte interaction, it is possible that the plant response would not be positive. Using plants ofChenopodium quinoa, an Andean crop with recognized nutritional values, and two antarctic root-endophytes whit proven benefits against different abiotic stresses in both their native and alternative hosts; we test the role of the symbiosis in Fv/ Fm and relative expression of NHX1 under control and salt-stress conditions of five quinoa accessions that differs in their tolerance to salinity. Hence, we evaluated these responses in plants with (E+) and without endophytes (E-) at different soil concentrations of NaCl. We observe a negative effect of salt in most quinoa accessions, in Fv/Fm and relative expression of NHX1. Among plants whit the antarctic symbionts, these effects were less pronounced, or even overcompensated by this symbiotic condition. Nevertheless, this was largely dependent of the genotype, and could being in some cases negative (R49 accession). In conclusion, the role of the proposed antarctic plant endophytes is highly dependent of the intensity of the abiotic stress and the own capacity of the plant host to tolerate the focal pressure, which in the case of quinoa appears to be highly related with its genotype.

137 The Andean Condor (Vultur gryphus) gut microbiome

El microbioma del cóndor andino (Vultur gryphus)

Pablo Berrios1,2,3, Rodrigo Santibañez3,4, J.Eduardo Martinez3,5, Alberto J. M. Martin3, Annette Trombert 2. (1) Biotecnología, Ciencias, Universidad Mayor (2) Microbial Genomics Lab, Centro de Genomica y Bioinformatica, Facultad de Ciencias, Universidad Mayor (3) Network Biology Lab, Centro de Genomica y Bioinformatica, Facultad de Ciencias, Universidad Mayor (4) Departamento de Ingenieria Quimica y Bioprocesos, Escuela de Ingenieria, Pontificia Universidad Católica de Chile (5) Programa de Doctorado en Genomica Integrativa, Vicerrectoria de Investigacion , Universidad Mayor (Sponsored by Annette Trombert)

The Andean condor (Vultur gryphus) is a New World vulture, belonging to the family Cathartidae, all of which are associated as maintainer of a “healthy” ecosystems due to its scavenging habits. Because of its diet, the Andean condor is in contact to a wide variety of bacteria and other microorganisms, which could produce toxins or be pathogenic to other species. However, neither the Andean condor nor its microbiome have been studied with deep sequencing technologies, impeding understanding of how the Andean condor tolerates its rotting diet or to discover at what extent its microbiome protects, aids or promotes digestion and maintenance of health.

We generated and analyzed a shotgun metagenomic sequence to identify bacterial and other microorganism taxa, and from that information we determined functional annotations. We identified bacterial taxa commonly associated to decomposing meat, such as Clostridium. More importantly, we identified bacteria that could be highly pathogenic to humans, such as C.perfringens. The bacterial composition is similar to other vultures and scavenger microbiomes, and highly dissimilar to others such as the human microbiome, indicating a specialization and a possible functional role.

CONICYT-PCHA/Doctorado Nacional/2014-21140377, Beca Doctoral Mayor, FONDECYT Regular 2018 :1181089

138 The weed Conyza sp. as reservoir for Colletotrichum species: ¿plant pathogens or potential biocontrol agents?

La maleza Conyza sp. como reservorio de especies de Colletotrichum: ¿patógenos de cultivos o potenciales agentes de biocontrol?

Martín Bonacci2, Melina Sartori2, Norma Formento1, Paula Barra2, Miriam Etcheverry2, Andrea Nesci2, Germán Gustavo Barros2. (1) INTA-EEA Paraná, Oro Verde, Entre Ríos (2) Universidad Nacional de Rio Cuarto

Conyza sp. es una planta nativa de América del Sur ampliamente distribuida en Argentina, que causa interferencia en cultivos estivales impactando en el rendimiento, por lo que es considerada una maleza. Además, puede ser reservorio de patógenos fúngicos del agroecosistema. Su control se realiza con herbicidas sintéticos, sin embargo la detección biotipos resistentes, hace que control biológico a través de enemigos naturales sea una alternativa. El objetivo fue evaluar la diversidad de cepas de Colletotrichum aisladas de plantas de Conyza y confirmar su patogenicidad tanto en la maleza como en cultivos extensivos. Se analizaron 34 aislamientos de Colletotrichum recuperados de hojas de la maleza con síntomas de enfermedad fúngica. Las cepas fueron identificadas de manera polifásica a través de análisis morfológicos, fisiológicos y secuenciación del gen GADPH. La combinación de los caracteres morfológicos y moleculares permitió discriminar 6 clados dentro del complejo de especies deColletotrichum . Respecto de los ensayos de patogenicidad, 13 cepas fúngicas fueron confirmadas como patógenas en plántulas de Conyza reproduciendo los síntomas observados a nivel foliar. Cuando se observó la patogenicidad en cultivos extensivos, ninguna cepa mostró patogenicidad en maíz y trigo; mientras que en soja, 11 de las 13 cepas mostraron lesiones en plántulas. Los resultados de especificidad muestran que al menos 2 cepas de Colletotrichum podrían se consideradas potenciales agentes de biocontrol de la maleza. Actualmente se están realizando más estudios para integrar un futuro micoherbicida en el marco de un manejo integrado de malezas.

Agencia Nacional de Promoción Científica y Tecnológica PICT 2102/16

139 New genomes from uncultured members of phylum Chloroflexi obteined from metagenomes from different wastewater treatment systems

Nuevos genomas de organismos no cultivables del filoChloroflexi obtenidos a partir de metagenomas de muestras de diferentes sistemas de tratamiento de aguas residuales

P. Bovio1, L. Guerrero2, A. Cabezas3, P. Oyarzúa4, L. Erijman2, C. Etchebehere1. (1) Laboratorio de Ecología Microbiana, Departamento de Bioquímica y Genómica Microbiana, Instituto de Ciencias Biológicas (2) Instituto de Investigaciones en Ingeniería Genética y Biología Molecular “Dr Héctor N. Torres” (INGEBI-CONICET), Buenos Aires, Argentina. (3) Laboratorio de microbiologia medioambiental, Departamento de Ciencias Medioambientales, Universidad Tecnologica, (UTEC), Durazno, Uruguay. (4) Grupo de investigación GENOCOV, Departaento de Química, Escuela de Ingenieraía, Universidad Autonoma de Barcelona, España.

El filoChloroflexi es reportado como uno de los grupos predominantes en sistemas de tratamiento de aguas residuales. Debido a que son difíciles de cultivar se sabe muy poco sobre su rol en estos sistemas. De la información obtenida a partir de los 7 aislamientos y 3 genomas ensamblados recuperados de sistemas de tratamiento se ha reportado que fermentan carbohidratos y tienen lenta tasa de crecimiento. Debido a su morfología filamentosa se sugiere que cumplen un rol en la formación de gránulos y flóculos, fundamentales en estos sistemas, pero por otro lado su sobrecrecimiento está relacionado con procesos de bulking. El objetivo fue ensamblar nuevos genomas del filo Chloroflexi a partir de metagenomas secuenciados de muestras de sistemas de tratamiento de aguas residuales. Se secuenciaron los metagenomas de 3 muestras de un reactor metanogénico UASB de tratamiento de una maltería (MO), 3 muestras de un reactor aerobio de tratamiento de residuos hospitalarios (RH) y 3 muestras de un reactor Anammox de laboratorio (AMX). Los metagenomas fueron secuenciados con Illumina-Hiseq-4000 (paired-end, 100 pb) y ensamblados con MEGAHIT. Se ensamblaron 4 genomas en muestras de MO, 5 de RH y 10 de AMX con una completitud entre 85.45 y 98.18. Los genomas fueron afiliados a las clases Anaerolinea, Ardenticatenia, y Caldilinea. Los porcentajes ANI estuvieron entre 70 y 84%, por lo tanto los genomas pertenecen a nuevas especies. Los genomas ensamblados representan especies nuevas dentro de las clases Anaerolinea, Ardenticatenia y Caldilinea. Se está estudiando sus funciones a partir de los datos genómicos.

Proyecto financiado por Fondo Vaz Ferreira

Beca de Doctorado, financiado por Agencia Nacional de Investigación e Innovación

140 Molecular and metabolic characterization of sediment-associated arsenotrophic bacterial communities of Salar de Huasco, Atacama Desert, Chile

Caracterización molecular y metabólica de comunidades bacterianas arsenotróficas asociadas a sedimentos del Salar de Huasco, Desierto de Atacama, Chile

Florencia Bravo1, Cristian Valenzuela1, Rubén Moraga2, Víctor Campos1. (1) Laboratorio de Microbiología Ambiental, Facultad de Ciencias Biológicas, Universidad de Concepción (2) Laboratorio de Microbiología Aplicada, Facultad de Recursos Naturales Renovables, Universidad Arturo Prat

Comunidades bacterianas resistentes a arsénico, son relevantes no solo por su potencial biotecnológico, sino que, desde el punto de vista de la astrobiología se teoriza que este tipo de metabolismo podría promover el desarrollo de microorganismos en ambientes extraterrestres similares a los encontrados en salares y lagos hipersalinos. Además, debido a que se presume que bacterias arsenotrofas podrían haber sostenido la productividad primaria en ambientes arcaicos y a que análisis filogenéticos de genes asociados al metabolismo del arsénico, sitúan la aparición de este tipo de enzimas, previo a la separación de bacterias y arqueas, el estudio de estos microorganismos podría contribuir al conocimiento de este tipo de metabolismo en un contexto evolutivo.

En el presente trabajo se caracterizaron molecular y metabólicamente, comunidades bacterianas de sedimentos del Salar de Huasco. Análisis filogenéticos indican que los phyla más abundantes corresponden a Proteobacteria y Bacteroidetes, mientras que la abundancia relativa de genes de resistencia a arsénico (GenesarsABCM ) indican que el gen arsB corresponde al más abundante (21%), seguido por el gen asrC (18%), arsA (9%) y aioA (8%), respectivamente, mientras que análisis fenotípicos de los aislados bacterianos muestran una amplia resistencia a metales pesados, en concentraciones incluso superiores a 100 mM.

Los resultados obtenidos, demuestran que comunidades bacterianas asociadas a este tipo de ecosistemas acuáticos que, de forma natural presentan altas concentraciones de arsénico, también exhiben una alta diversidad génica de resistencia a este metaloide, lo que puede traducirse en el aislamiento de cepas bacterianas con alto potencial biotecnológico.

FONDECYT 11130383

141 Mercury-polluted agricultural soil bioremediation by Cupriavidus metallidurans strain MSR33 in a rotary drum bioreactor

Biorremediación de suelos agrícolas contaminados con mercurio por Cupriavidus metallidurans cepa MSR33 en biorreactor tambor rotatorio

Guillermo Bravo1,3, Paulina Vega-Celadón2, Juan Carlos Gentina4, Michael Seeger1. (1) Depto. Quimica, LabMMBA, Universidad Técnica Federico Santa María, Valparaiso, Chile. Avenida España 1680 (2) Quimica, Universidad Técnica Federico Santa María, Valparaiso, Chile. Avenida España 1680 (3) Escuela de Agronomia, Pontificia Universidad Católica de Valparaiso (4) Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Valparaiso, Chile. Avenida Brasil 2085

Mercury is a toxic element that affects organisms and biogeochemical cycles. In Chile from 120 to 383 tons Hg year-1 are released to soils. Mercury bioremediation is based on the reduction of Hg2+ to Hg0. Mercury bioremediation of soil has been scarcely studied. The objective of this study was establish a bioremediation process using Cupriavidus metallidurans MSR33 of a mercury-polluted agricultural soil in a rotary drum reactor (RBD). Agricultural soils were collected and spiked with 20-30 ppm mercury. 20 L volume RDB was constructed for the treatment of mercury-polluted soils using C. metallidurans MSR33. The variables: cellular concentration, addition of thioglycolate, reinoculation and mercury concentration were analyzed for soil bioremediation in RDB. High MSR33 cell concentrations increased the bioremediation rate of mercury-polluted soils. Thioglycolate enhanced mercury removal from soils. No effect of cell reinoculation of strain MSR33 on soil bioremediation was observed. Bioremediation was not affected by mercury concentration up to 30 ppm. Six mercury-tolerant strains were isolated from bioremediated soils. The isolates were identified as Arthrobacter sp. SB1a, Bergeyella sp. SB2a, Bacillus sp. SB1B, Planomicrobium sp. SB2b, Brevundimonas sp. SB3b and Ochrobactrum sp. SB4b. Strains SB1a, SB3b and SB4b possess the merG gene that is associated with the plasmid pTP6 present in C. metallidurans MSR33, suggesting the horizontal transfer of the plasmid pTP6 to native soil bacteria. Mercury soil bioremediation byC. metallidurans MSR33 in RDB is a new approach for the decontamination of mercury-polluted agricultural soil.

Anillo GAMBIO ACT172128, FONDEQUIP EQM170194

142 Taxonomic and metabolic analysis of the microbial community of Costa Rica thermal and mineral springs

Análisis taxonómico, metabólico y funcional de microorganismos fuentes minerales y termales de Costa Rica

Laura Brenes-Guillén1, Daniela Vidaurre-Barahona1, Guillermo E. Alvarado2, Marielos Mora-López1, Beatriz Díez3, Carlos Pedrós Alió4, Lorena Uribe-Lorío1. (1) Centro de Investigación en Biología Celular y Molecular (CIBCM), Universidad de Costa Rica, Ciudad Universitaria Rodrigo Facio, San José, Costa Rica (2) Escuela Centroamericana de Geología,Universidad de Costa Rica, San José, Costa Rica (3) Departamento de Microbiología y Genética, Pontificia Universidad Católica de Chile, Santiago, Chile (4) Departamento de Biología de Sistemas,Centro Nacional de Biotecnología, CSIC,Madrid, Spain

Costa Rica es un país geológicamente muy activo, con una variedad de volcanes y nacientes de aguas minerales y termales con características fisicoquímicas muy particulares. Estas características hacen de las fuentes sitios ideales para el estudio de la adaptación de los microorganismos a los ambientes extremos, así como para la caracterización de la diversidad metabólica y filogenética de las comunidades microbianas que habitan estos ambientes únicos. El objetivo de este estudio es analizar y comparar datos de secuenciación de metagenomas para la búsqueday caracterización de enzimas hidrolíticas termoestables, así como la identificación taxonómica de las comunidades. Se tomaron muestras de agua y tapetes microbianos para el cultivo de microorganismos y la extracción de ADN ambiental. Posteriormente, se realizó la secuenciación con la plataforma Illumnia Miseq e Illumina Hiseq. Para el análisis taxonómico se utilizó el paquete de herramientas Qiime2. Para el estudio funcional, se depuró la calidad de las secuencias con el programa Trimmomatic, y se realizó el ensamblaje con el programa Megahit y la anotación con Prodigal y Prokka. Además, se determinó el efecto de la temperatura y el pH en las comunidades microbianas. Este estudio se demostró que los microorganismos como Cyanobacteria y Chloroflexi dominan los tapetes microbianos, siendo Chloroflexi el más abundante conforme aumenta la temperatura. En un análisis metabólico preliminar, se encontraron genes de diversas categorías funcionales, tales como la degradación de xenobióticos y metales pesados. Esta investigación ofrece una oportunidad para caracterizar las vías metabólicas de los microorganismos y generar nueva información con potencial biotecnológico. Los resultados forman parte de diversos esfuerzos de investigación para la exploración y conservación de los recursos biológicos disponibles en las fuentes minerales y termales costarricenses, que permitan generar conocimiento a nivel ecológico y metabólico de estos ambientes, así como la biodiversidad a escala microscópica.

143 Structure and composition of bacterial and viral communities from thermophilic phototrophic mat at Kroner Lagoon (Antarctica)

Estructura y composición de comunidades virales y bacterianas de un tapete termofílico y fototrófico en la laguna Kroner (Antártica)

Marianne Buscaglia1, Oscar Salgado1, Tomás Alarcón-Schumacher2, Sergio Guajardo-Leiva1, Beatriz Díez3,1. (1) Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile (2) Max Planck Institute for Marine Microbiology (3) Center for Climate and Resilience Research (CR2), Universidad de Chile

Kroner is an intertidal geothermal lagoon located on Deception Island (Antarctica), which is subject to constant environmental perturbances on a daily basis. Kroner has characteristics of both marine and freshwater environments, with pulses of both cold and thermal waters. This unconventional combination of physicochemical factors generates a unique environment of unexplored biodiversity. Consequently, the goal of the present work was to determine the structure and composition of microbial and viral communities in phototrophic mats present in the Kroner lagoon. Here, using the recruitment of the 16S rRNA gene of two cellular metagenomes (16SmiTags) at different temperatures (32°C and 44°C), we determine that the bacterial community is dominated by Alphaproteobacteria 64%) followed by Cyanobacteria 30%) at the lowest temperature. Meanwhile, opposite abundances were found at the highest temperature, with Cyanobacteria as the dominant taxa ( 44%), followed by Alphaproteobacteria (∼ 27%) and Flavobacteria ( 9%).(∼ Associated to these bacterial communities, we detected 113 viral genotypes (contigs > 5000 bp) that were assigned to the families Siphoviridae 42%), ∼Myoviridae 3%) and Podoviridae 8%),(∼ which were predicted to infect∼ mainly Actinobacteria and Proteobacteria. This work not only allowed to identify the diversity and composition of the bacterial communities, but also(∼ shed light on the (∼1taxonomic composition of(∼ the most abundant viruses populations present in this unique Antarctic ecosystem.

FONDECYT nº 1181656, FONDAP 15110009.

144 Bacterial communities associated with heterocystous cyanobacteria in the cycad coralloid root may have a role in symbiosis

Las comunidades bacterianas asociadas a cianobacterias heterocisticas en la raíz coraloide de las cícadas tienen un rol funcional en la simbiosis

Edder Daniel Bustos-Diaz1, Karina Gutiérrez-García1, Angélica Cibrián-Jaramillo2, Francisco Barona-Gómez1. (1) LANGEBIO, Evolution of metabolic diversity laboratory, CINVESTAV (2) LANGEBIO, Ecological and evolutionary genomics, CINVESTAV

Heterocystous cyanobacteria, prokaryotic heterotrophs that fix nitrogen in specialized cells called heterocysts, can form symbiotic relationships with various hosts. Among these symboses we find that formed with cycads, one of the oldest gymnosperms. The symbiotic cyanobacteria at the coralloid root, the cycad symbiotic organ, has been found to be associated with a diverse bacterial community. A metagenomic exploration of bacterial communities from cycads species from different geographical locations revealed a taxonomic core comprised of Caulobacterales, Sphingomonadales and Rhizobiales. These bacterial orders are also found in bacterial communities associates with cyanobacteria in symbiosis with other hosts. Our results indicate that the nitrifying activity of Rhizobium found in symbiosis between the aquatic fern Azolla and cyanobacteria is also part of the cycad-cyanobacteria symbiosis, suggesting that the cycad symbiosis is also dependent upon bacteria-bacteria interactions.

145 Influence of F/M ratio and upflow velocity in microbial population dynamics and stability of aerobic granular sludge during continuous mode operation

Influencia de la razón A/M y la velocidad ascencional en la dinámica microbiana y estabilidad del lodo granular en un reactor aerobio operando en modo continuo

Oscar Franchi 1, María Ignacia Álvarez2, José Luis Campos1, Javier Santibañez1, Daniel Valenzuela1, 1, Marisol Belmonte2, Alba Pedrouso3, Paula Carrera 3, Ángeles Val Del Río3, Anuska Mosquera-Corral3. (1) Universidad Adolfo Ibáñez, Viña del Mar, Chile (2) Departamento de Medio Ambiente, Facultad de Ingeniería, Universidad de Playa Ancha de Ciencias de La Educación (3) Departamento de Ingeniería Química, Escuela Técnica Superior de Ingeniería, Universidad de Santiago de Compostela, España

The use of granular aerobic systems is an attractive technology to deal with the expected increase in organic load due to population growth. Current sludge granulation technologies are based on discontinuous processes and are not feasible to implement in plants that already operate in continuous mode. Key variables to maintain a stable granulation process are the selection of biomass with good settling and the presence of a feast/famine stages during the process. Therefore, the upflow velocity in the settler as well as the food to microorganisms ratio (F/M) could be relevant operational parameters to achieve stable granules. In this work, the formation process and stability of aerobic granules are evaluated using two continuous reactors: a piston flow reactor and a stirred tank reactor divided in two chambers with a volume ratio of 0.2, designed to emulate the feast/famine stages. In both reactors the F/M ratio was modified by changing the inlet substrate concentration (500, 1,000 and 2,000 mg ∙ L-1 of COD) and the effect of granular biomass selection was evaluated by imposing different upflow velocities in the settler (1.7, 2.7 and 5.3 m ∙ h-1). The microbial populations dynamics of granules over time was analyzed by IonTorrent sequencing technology and correlated with granules stability in terms of fractal dimension and the total suspended solids concentration in the reactors. The results of this study provides relevant information regarding the reactor´s design and the operational parameters to consider in order to implement a stable granular aerobic sludge technology in continuous mode.

Chile: FONDECYT 1180650, FONDECYT 11181107, CORFO/14ENI2-26865, CONICYT PIA/BASAL FB0002, CONICYT/ FONDAP/15130015.

España: GRANDSEA (CTM2014-55397-JIN), TREASURE (CTQ2017-83225-C2-1-R).

146 Phosphomonoesterase activity and bacterial phosphomonoesterase gene abundance in two rivers from southern Chile

Actividad fosfomonoesterasa y abundancia de genes fosfomonoesterasa bacteriana en dos ríos del sur de Chile

Marco Antonio Campos1,2, Jacqueline Jovanka Acuña1,2, Joaquín Ignacio Rilling1,2, Milko Alberto Jorquera1,2. (1) Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera (2) Applied Microbial Ecology Laboratory (EMAlab), Departamento de Ciencias Químicas y Recursos Naturales, Universidad de La Frontera (Sponsored by FONDECYT N°3180198 (postdoctoral), N°1160302 And N°11160112 Projects.)

Phosphorus (P) is an essential nutrient for life, but is also categorized as a pollutant because is constantly deposited in water body sediments by human action, contributing to the eutrophication and frequency of harmful algae blooms. In aquatic environments, P recycling is governed by several abiotic and biotic factors, being key the activity of bacterial enzymes (such as phosphomonoesterases [Pases]). In this context, rivers are important “ecosystem services” in southern Chile, but scarcely studied, particularly in P recycling regulated by bacterial activity. The objective of this study is to determine the phosphomonoesterase activity and bacterial phosphomonoesterase gene abundance in two rivers from southern Chile. Superficial sediment samples were taken in triplicate from four anthropized points of Imperial and Toltén rivers during winter 2018. Nutrient contents (C, N and P), enzymatic activity (alkaline [AKP] and acidic [AP] Pases) and bacterial gene abundance (total bacterial [16S rDNA], alkaline [phoD and phoX] and acidic [phoC] Pases) were measured. Then, data were collected and subjected to principal component analysis (PCA) and ANOVA parametric test (p<0.05). PCA analysis showed a clear separation between both rivers, where the higher values of P contents, Pase activity and Pase genes were positively correlated with Imperial river. Interestingly, in general the highest values were found in the coast closest sites with significant statistical differences respect to the coast farthest ones. Our results showed significant differences between both rivers and along their courses. However, deeper studies are required to confirm these observations.

Acknowledgment to the FONDECYT N°3180198 (postdoctoral), N°1160302 and N°11160112 projects.

147 Identification of halophilic and halotolerant microorganisms with antimicrobial and cytotoxic activity

Identificación de microorganismos halófilos y halotolerantes con actividad antimicrobiana y citotóxica

Angela Cantillo González1, Carolina Díaz Cárdenas2, Laura Yinneth Rojas3, Tito Sandoval3, Susana Fiorentino3, Jorge Robles4, Sandra Baena2, María Mercedes Zambrano5. (1) Ingeniería Hidráulica, Ingeniería, Pontificia Universidad Católica de Chile (2) Unidad de Saneamiento y Biotecnología Ambiental, Departamento de Biología, Pontificia Universidad Javeriana (3) Grupo de Inmunobiología y Unidad de Investigación en Ciencias Biomédicas, Pontificia Universidad Javeriana (4) Grupo de Investigación Fitoquímica, Pontificia Universidad Javeriana (5) Corporación Corpogen

Microorganismos de ambientes extremos, como minas de sal, tienen potencial metabólico que es de interés para el desarrollo biotecnológico. En Colombia, la bioprospección de productos microbianos es todavía incipiente y se sabe poco sobre microorganismos aislados de ambientes salinos. El objetivo de este trabajo fue evaluar la actividad citotóxica y antimicrobiana de microorganismos halófilos y halotolerantes obtenidos de minas de sal en Colombia e identificar moléculas relacionadas a la actividad citotóxica. Un total de 92 microorganismos fueron aislados de sedimentos y rocas de Colsaminas Zipaquirá/Colombia. La clasificación taxonómica, realizada mediante análisis de secuencia de 16S ADNr, mostró que 56% de las cepas pertenecían a géneros de Firmicutes y el resto a filos Proteobacteria, Bacterioidetes y Actinobacteria. Para evaluar la actividad antimicrobiana, se ensayaron 48 cepas mediante la técnica de difusión en agar usando sobrenadante, células y extractos de cloroformo y acetato de etilo obtenidos a partir de la fracción extracelular. Los extractos también fueron evaluados para citotoxicidad usando la técnica de rojo neutro contra dos líneas celulares, 4T1 y MCF-7. Dieciocho cepas mostraron actividad citotóxica contra ambas líneas celulares. Adicionalmente, 17 mostraron actividad antimicrobiana. Las cepas 22, 42 y 63 pertenecientes al género Bacillus tuvieron actividad contra Escherichia coli, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa y Klebsiella pneumoniae. Moléculas relacionadas a la actividad citotóxica de las cepas 22 (Bacillus subtilis) y 24 (Ornithinimicrobium sp.) no tuvieron coincidencia en el Diccionario de Productos Naturales de Chapman y Hall. Estos resultados muestran que microorganismos halófilos y halotolerantes son potenciales productores de nuevos compuestos con esta actividad.

Este trabajo fue financiado por Colciencias; Pontificia Universidad Javeriana y Corpogen, bajo MAD contrato No. 0104.

148 Evaluation of Antibacterial activity of the secretions produced by the skin of the frog Boana xerophylla en symbiosis with its native microbiota

Evaluación de la actividad antibacteriana de las secreciones producidas por la piel de la rana Boana xerophylla en sinergismo con su microbiota nativa

Julian Camilo Casas-Vargas1,2, Carolina Muñoz-Camargo3, Helena Groot3. (1) Ciencias Biológicas, Ciencias, Universidad de Los Andes (2) Ingeniería Hidráulica, Ingeniería, Pontificia Universidad Católica de Chile (3) Ingeniería Biomédica, Ingeniería, Universidad de los Andes (Sponsored by .)

En los últimos años, los péptidos antimicrobianos (AMPs) secretados por la piel de anfibios, como la especie Boana xerophylla, han surgido como fuentes importantes de sustancias antibióticas para contrarrestar el surgimiento de cepas bacterianas multi-resistentes. En adición, se ha demostrado que bacterias simbiontes asociadas a la piel de rana también presentan esta actividad. A pesar de esto, no existen ensayos en los cuales se evalúe actividad inhibitoria de la interacción entre la piel de la rana y su microbiota nativa. El objetivo de esta investigación fue evaluar la actividad antibacteriana de la simbiosis entre la piel de la rana B. xerophylla con su microbiota nativa. Para este fin, tres especímenes fueron capturados de los cuales se obtuvieron 77 aislamientos bacterianos identificados por 16s ADNr de las familias Enterobacteriaceae y Pseudomonadaceae, principalmente. Paralelamente, la piel de cada espécimen fue cultivada junto con su microbiota nativa (técnica de Micro-órganos) para obtener medios condicionados (MCs). A partir de estos se realizaron ensayos antimicrobianos contra las cepas bacterianasStaphylococcus aureus ATCC 25923 y55, Pseudomonas aeruginosa PAO1 y M18. Como resultado, se observó que los MCs, en diluciones 1:2, presentaron actividad inhibitoria frente a las cepas de P. aeruginosa en ensayos con y sin microbiota nativa. Sin embargo, los MCs indujeron actividad proliferativa en las cepas de S. aureus en diluciones 1:20. En conclusión, las secreciones obtenidas del cultivo de piel deB. xerophylla en conjunto con las bacterias nativas de esta poseen actividad inhibitoria y proliferativa dependiente de la concentración de MCs.

Facultad de Ciencias de la Universidad de los Andes en la convocatoria 2016-2 Para la Financiación de Proyectos de Investigación, Categoría: Estudiantes de Maestría y Doctorado.

149 The role of gut microbiota on the thermal physiology of Drosophila subobscura

El rol de la microbiota intestinal en la fisiología térmica de Drosophila subobscura

Luis Castañeda1, Angélica Jaramillo2. (1) Programa de Genética Humana, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile (2) Laboratorio de Biología Integrativa, Universidad de Chile

Gut microbiota has an important role in host traits as immune response and energy metabolism. However, the role of gut microbiota on adaptive responses to climate change are have not completely understood. Here, we evaluated the role of gut microbiota on heat tolerance, the resilience of gut microbiota to heat stress and its consequences on life- history traits of Drosophila subobscura. We found that flies harboring normal microbiota (conventional flies) exhibited higher thermal tolerance than axenic flies (germ-free flies), but only at chronic thermal stress. We also found that heat stress modified the gut microbiota structure, altering richness and diversity indices. Finally, axenic flies showed a decreased fecundity and viability after a heat shock, but life-history traits of conventional flies were not affected after by this thermal stress. Conclusions: (1) gut microbiota has an important role in heat tolerance, suggesting a nutritional and protective role mediated by gut microbiota; (2) the Drosophila gut microbiota is sensible to heat stress, modifying the diversity and abundance of gut bacteria; and (3) gut microbiota plays a thermoprotective role on Drosophila, buffering the impact of thermal stress on fitness-related traits. Therefore, gut microbiota provides to animal hosts an additional source of phenotypic variation to respond to climate change challenges. We will continue exploring the role of gut microbiota on heat tolerance to understand the underlying physiological mechanisms of the stress resistance in insect hosts.

FONDECYT 1140066 and ENL09/18.

150 Genetic diversity ofFlavobacterium psychrophilum and its phages: implications for phage therapy applications

Diversidad genética de Flavobacterium psycrophilum y sus fagos: implicaciones para aplicaciones en fagoterapia

Daniel Castillo1, Johanna Jorgensen1, Sundell Krister2, Valentina Donati3, Mathias Middelboe1. (1) Department of Biology, Marine Biological Section, University of Copenhagen (2) Environmental and Marine Biology, Laboratory of Aquatic Pathobiology, Åbo Akademi University (3) National Veterinary Institute, Section for Bacteriology and Pathology, Technical University of Denmark

Flavobacterium psychrophilum is a serious fish pathogen in salmonid aquaculture worldwide that causes cold water disease (CWD) and rainbow trout fry syndrome (RTFS). Due to increased antibiotic resistance, pathogen control using phages (phage therapy) has been explored as a possible alternative treatment. However, a successful phage therapy treatment requires a detailed knowledge of the phage-bacteria genomic composition, resistance mechanisms to phage exposition and its implications on the pathogen virulence. We have analyzed, by whole-genome sequencing, the genetic diversity of 25F. psychrohilum strains, 33 phages, and 27 phage-resistance isolates. Genomic comparison analysis showed that F. psychrophilum strains possessed an open pan genome but with limited genetic diversity, independent of isolation sites. In addition, phage genome analysis showed that they grouped in four different genetic clusters based on genetic composition and gene content, of which three groups contain candidates for phage therapy applications. Two highly virulent strains were exposed to broad host range phages to monitor resistance development. All phage-resistant isolates contained mutations in genes related to gliding motility, which were associated with a number of derived effects on the phenotype properties of the pathogen, including reduced virulence in vitro and in vivo conditions. Altogether, the results demonstrate that phage-driven physiological changes associated with resistance have large implications for the impact of the pathogen in aquaculture by reducing pathogen virulence, and these effects of phage resistance are therefore important for the ongoing exploration of phage-based control of F. psychrophilum.

BONUS FLAVOPHAGE project has received funding from BONUS (Art 185), funded jointly by the EU and Innovation Fund Denmark.

151 Evaluation of organic extracts of microbial cultures from Atacama Desert on the cellular viability of human keratinocytes

Evaluación del efecto de extractos orgánicos de origen microbiano del Desierto de Atacama en la viabilidad celular de queratinocitos humanos Francisca Castillo1,3,5, Carolina Cabalín4, Fernanda Huerta4, Johanna Cortés1,2,5, Arturo Borzutzky4, Luis Venegas4, Martha Hengst1,5. (1) Laboratorio de Ecología molecular y Microbiología aplicada, Departamento de Ciencias Farmacéuticas, Universidad Católica del Norte (2) Programa de Magister en Ciencias biomédicas con mención en Microbiología aplicada, Universidad de Antofagasta (3) Programa de Magister en Ciencias biomédicas con mención en Fisiología aplicada, Universidad de Antofagasta (4) Laboratorio de Inmunología y Alergia Traslacional, Facultad de Medicina, Pontificia Universidad Católica de Chile (5) Centro de Biotecnología y Bioingeniería

El Desierto de Atacama (DA) se caracteriza por ser un ambiente de extrema aridez, alta radiación solar, salinidad y oscilación térmica diaria, transformándolo en uno de los ambientes más inhóspitos del planeta para el desarrollo de vida. Los microorganismos (MO) que habitan aquí han desarrollado estrategias para lidiar con el estrés abiótico, produciendo una gran variedad de compuestos bioactivos de interés biotecnológico para la industria farmacéutica y cosmética. Por otro lado, la piel es el órgano más grande del cuerpo humano y su funcion principal es servir como barrera protectora contra agentes externos (e.g., químicos, físicos y biológicos), cuya exposición a factores extremos puede generar daño a nivel celular afectando su funcionamiento. El propósito de esta investigación fue evaluar el efecto de compuestos bioactivos obtenidos desde MO aislados del DA, sobre la viabilidad de una línea celular de epidermis. Para ello, se utilizaron queratinocitos humanos (HaCat) y se determinó la viabilidad celular mediante ensayo de MTT post incubación de concentraciones crecientes del extracto crudo (0-1000 μg ml-1) durante 24 y 48 horas. Los resultados mostraron que a altas concentraciones (50 a 1000 ugml-1) el extracto presentó mayor toxicidad al cultivo de queratinocitos en 48 horas de tratamiento; mientras que a una baja concentración (1-10 μgml-1) no se observó un efecto tóxico en las células de la piel. Estos resultados muestran por primera vez el efecto de toxicidad de un extracto orgánico proveniente de bacterias del Desierto de Atacama en células de piel humana.

Fondecyt regular 1140179; 1140356, 1181773, 1171324, 3180572, CeBiB (FB-0001).

152 Vesiculation is a common phenomenon in extreme acidophilic bioleaching bacteria of the Acidithiobacillus genus

La vesiculación es un fenómeno común en las bacterias biolixiviantes acidofilas extemas pertenecientes al género Acidithiobacillus

Matias Castro1,2, Stefano Rossoni1, Dilanaz Arisan1, Yasna Gallardo1, Manuel Varas-Godoy3, Patricio Martínez- Bellange4, Raquel Quatrini1,2. (1) Microbial Ecophysiology Laboratory, Santiago, Chile, Fundación Ciencia & Vida (2) Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile (3) Cancer Cell Biology Laboratory, Centro de Biología Celular y Biomedicina (CEBICEM), Facultad de Medicina y Ciencia, Universidad San Sebastián (4) Codelco Tec, Spa, Santiago, Chile

The physiology of bioleaching bacteria has been studied for decades in the context of biomining of mineral ores and environmental pollution through acid mine drainage. These phenomena are intimately related with the attachment of bacterial cells and biofilm formation on solid substrates, which in turn depend largely on the extracellular polymeric substances secreted by bacteria. For many years, we have overlooked important matrix components in biofilms formed by relevant acidophiles, such as Acidithiobacillus species. Among them, are membrane vesicles (MVs), nano-sized structures produced and secreted by bacteria under diverse growth conditions. In well-studied bacterial models, these extracellular sacs contain a wide range of cellular products and fulfill roles as diverse as waste disposal, cell-cell communication and horizontal gene transfer. Yet, the roles of MVs in acidophiles and in bioleaching are presently unknown. In this work, we show that production and secretion of MVs is a common phenomenon in different Acidithiobacillus species and under different growth conditions, including temperature variations and attached vs. planktonic lifestyles. MVs produced were characterized in terms of concentration and size distribution profiles by nanoparticles tracking analysis, and protein and DNA content by qualitative analysis. Using A. caldus as model, we explored further the specificity of the cargo of these MVs and assayed the physiological effect of MVs on population-responses coordination (swarming motility and biofilm formation). Results obtained are discussed in the context of the importance of these structures in behavioral and ecological interactions.

Acknowledgements: Fondecyt 1181251; Basal AFB170004; Millennium Science Initiative, Ministry of Economy, Development and Tourism of Chile under Grant “Millennium Nucleus in the Biology of the Intestinal Microbiota”; CodelcoTech Project 04-18.

153 A first insight into microbial communities of a unique human-impacted ecosystem in Patagonia

Comunidades microbianas de un ecosistema bajo impacto antropogénico en Patagonia

Katterinne Mendez3, Sergio Guajardo-Leiva1, Florence Gutzwiller3, Claudio Meneses2, Eduardo Castro-Nallar3. (1) Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello (3) Center for Bioinformatics and Integrative Biology, Facultad de Ciencias de la Vida, Universidad Andrés Bello

Humans have affected the Earth System in indelible ways, in what has been dubbed a new epoch in Earth’s geological history, the Anthropocene. This new epoch is characterized by humans recent, yet profound, influence on the global environment ranging from biogeochemical cycles to the evolution of life. Human industrial activity is one of the factors contributing to these long-lasting effects on the Earth System, where food animal production, e.g., animal husbandry and aquaculture, plays a key role. Here, we reveal the composition, structure, and function of microbial communities of the Comau Fjord (42ºS) and discover marked seasonal changes notable even at the Phylum level, including Dark Matter taxa (e.g., high levels of Thaumarchaeota, Cyanobacteria, and Actinobacteria phyla in Winter, as opposed to high levels of Verrucomicrobia, Proteobacteria, and Bacteroidetes in Summer). We detect consistent signals of antibiotic resistance genes, including against antibiotics used in aquaculture. With more than 70 samples (20 M reads on average), we were able to reconstruct > 100 high-quality microbial genomes, which combined with single- cell sequencing and Hi-C genomes, comprise the largest collection of fjord genomes available to date. Altogether, we were able to associate taxonomic composition with environmental drivers such as temperature and salinity, and to identify microbial lineages that carry antibiotic resistance genes and mobile genetic elements.

ECN was funded by “CONICYT-FONDECYT de iniciación en la investigación 11160905”

154 Specific niche adaptations and arsenic tolerance emerge as a manifestation of the pangenome components in polyextremophile Exiguobacterium strains isolated from different Salar de Huasco sites

Las adaptaciones nicho especificas y la tolerancia a arsénico que presentan cepas poliextremófilas de Exiguobacterium aisladas de diferentes puntos del Salar de Huasco emergen como una manifestación de los compartimientos del pangenoma

Juan Castro-Severyn1,2, Coral Pardo-Esté1, Yoelvis Sulbaran1, Naiyulin Morales1, Diego Lorca1, Francisco Romero1, Laurence Molina3, Franck Molina3, Francisco Remonsellez4, Eduardo Castro-Nallar2, Claudia P Saavedra1. (1) Laboratorio de Microbiología Molecular. Facultad de Ciencias de la Vida, Universidad Andrés Bello. Santiago - Chile (2) Center for Bioinformatics and Integrative Biology. Facultad de Ciencias de la Vida, Universidad Andrés Bello. Santiago - Chile (3) Sys2Diag CNRS/Alcediag, CNRS UMR3145, Montpellier - France. (4) Laboratorio de Microbiología Aplicada y Extremófilos, Facultad de Ingeniería y Ciencias Geológicas, Universidad Católica del Norte. Antofagasta - Chile

Polyextremophilic bacteria are those able to thrive in environments with multiple stressors, highlighting Exiguobacterium genus for its plasticity and ubiquity. Salar de Huasco (SH) is an poly-extreme habitat where these bacteria can be found, exposed to several factors such as high atmospheric pressure, UV radiation and salinity; changing temperatures and the presence of toxic compounds like arsenic (As). However, the physiological and molecular mechanisms that allow them to prosper in these environments are yet to be described. Our objective is to evaluate if specific niche adaptations emerge from a particular pangenome compartment. In addition, we aimed to describe the composition of the bacterial communities through 16S rRNA amplicon sequencing and the environmental conditions that could be affecting, being the most relevant factors salinity and As concentration. We also isolate, identify, and sequence the genomes of 14 Exiguobacterium strains with different As tolerance levels from five SH sites/niches, to describe through comparative genomics, the functional potential that could explain their As tolerance levels and the ability to resist poly-stress. Taken together, our phylogenetic results show that although these strains are monophyletic regarding all Exiguobacterium genomes (GenBank), there is genotypic variability among them, as evidenced by the COG composition of their accessory genome and its size. Furthermore, these observations are supported by experimental evidence (growth patterns, transcriptional expression and enzymatic activity) of three strains under arsenic tratments. Therefore, we can conclude that the strains and communities seem to be adapted and shaped to overcome their particular and contrasting environmental conditions.

CPS: CONICYT FONDECYT 1160315, ECOS-CONICYT 170023 and Núcleo-UNAB DI-3-17/N. FR: CONICYT FONDECYT 11100414. ECN: CONICYT-FONDECYT Inicio 11160905. JCS: CONICYT National Doctoral Fellowship 2015.

155 Changes in the bacterial community of a chronically contaminated soil as a consequence of combined bioremediation strategies

Cambios en la comunidad bacteriana de un suelo crónicamente contaminado como consecuencia de estrategias combinadas de biorremediación

Martina Cecotti1, Irma Susana Morelli2,1. (1) Laboratorio de Biorremediación de Hidrocarburos, Centro de Investigación y Desarrollo en Fermentaciones Industriales (2) Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA)

Múltiples factores pueden afectar la efectividad de estrategias de biorremediación de suelos contaminados con hidrocarburos policíclicos aromáticos (PAH). Se propuso contribuir al mejoramiento de dichas estrategias comparando 4 tratamientos sobre un suelo salino y crónicamente contaminado. Se prepararon microcosmos de 500 g de suelo seco: (C): atenuación natural; (CT): 19 mg g-1 Triton X-100; (CAM): 108 UFC g-1 Sphingobium sp. AM; (AM/T): 19 mg g-1 Triton X-100 y 108 UFC g-1 AM. Los microcosmos fueron incubados por 7 meses a 24°C y 4±1%H (55% capacidad de retención de agua). El último mes fueron suplementados con Nitrofoska®. Limitada degradación de PAH se presentó en C (19±1%, GC-FID), posiblemente por estrés osmótico o intermediarios de degradación acumulados por la historia del suelo; se descartó la biodisponibilidad como limitante al detectarse alta proporción de PAH solubles. En CAM, la secuenciación de amplicones 16S-rADN (Illumina-MiSeq) evidenció el establecimiento temporal de AM, a la cual podría atribuirse el 60±10% de degradación (sólo a expensas de fenantreno y fluoreno), impactando levemente en la comunidad bacteriana indígena, lo que indicaría baja relación entre el inoculante y dicha comunidad. Los microcosmos CT y AM/T mostraron grandes cambios en la comunidad y aumento de secuencias asociadas al metabolismo de lípidos y xenobióticos (predicción mediante PICRUST), sin evidencias de establecimiento de AM en AM/T. En AM/T se observó 77±8% de degradación, incluyendo PAH de alto peso molecular, significativamente mayor a CT (5±7%). El impacto sobre la comunidad bacteriana por la combinación de estrategias permitiría superar diversos factores limitantes de degradación.

156 Disentangling interspecific transmission: lessons from vector-borne diseases shared by Andean foxes and free-ranging dogs in human-dominated landscapes of Central Chile

Entendiendo la transmisión interespecífica: lecciones de enfermedades transmitidas por vectores y compartidas por zorros Andinos y perros callejeros en zonas de Chile central, dominadas por el ser humano

Aitor Cevidanes1, Sophia Di Cataldo1, Claudia Ulloa2, Irene Sacristán1, Andrea D. Chirife1, Carla Barria-Loaiza1, Nina Rygh3, Nicole Sallaberry1, Sebastián Klarian1, Fernando Esperón4, Javier Millán1. (1) Universidad Andrés Bello (2) Universidad de Chile (3) Nottingham Trent University (4) INIA (España)

Landscape anthropization may facilitate pathogen transmission between domestic hosts and wildlife. Andean foxes (Lycalopex culpaeus) thrive in human-dominated landscapes around Santiago (Chile), where free-ranging dogs abound. We aimed to evaluate whether foxes and dogs share ticks and vector-borne pathogens and to elucidate drivers of transmission. Molecular characterization of ticks and blood pathogens from 87 foxes and 111 sympatric dogs was performed. Drivers of transmission were tested by correlating the pathogen/parasite infection in foxes with three proxies of probability of contact with dogs: i) spatial analysis (fox distance to the nearest household and household density into the fox’s home range); ii) fox exploitation of food of anthropogenic origin throughout stable isotope analysis; and iii) burden of antimicrobial resistance genes in fox feces analyzed by qPCR. While Amblyomma tigrinum (At) ticks (typical from South-American foxes) were frequent on foxes, Rhipicephalus sanguineus (Rs) (a cosmopolitan dog tick) was the most prevalent in dogs. A similar tendency was observed forHepatozoon sp. (probably transmitted by At, only found in foxes), and Anaplasma platys (transmitted by Rs, much more prevalent in dogs). Hemotropic Mycoplasma spp. were found in both species with similar prevalences. Molecular analysis confirmed that some sequence types of all these agents are present both in foxes and sympatric dogs. No clear association was observed between landscape anthropization and the occurrence of pathogens/parasites in foxes. Despite the different ecological preferences of the ticks, spillovers seem to be occurring in the study area. Fox’s close proximity to human settlements seems unnecessary for interspecific transmission.

Fondecyt Regular 1161593 (CONICYT, Chile)

157 Rhizospheric actinomycetes isolated from organic cultures of native potato Solanum tuberosum, L. and evaluation of its antagonistic activity against Phytophthora infestans (Mont) de Bary

Actinomicetos rizosféricos aislados de cultivos orgánicos de papa nativa Solanum tuberosum, L. y evaluación de su actividad antagonista a Phytophthora infestans (Mont) de Bary

Astrid Carolina Chumpitaz1, Carolina Quispe Soto 1, Nadia Galindo Cabello1, Junior Caro Castro1, Lisset Sara Tupa Andrade1, Jeanne Alba Luna1, Jorge León Quispe1. (1) Lima, Ciencias biológicas, Universidad Nacional Mayor de San Marcos

Introducción: La papa (Solanum tuberosum L.) es el cuarto cultivo de mayor consumo a nivel mundial. En Perú, más de 600 000 agricultores disminuyen su producción debido a problemas fitosanitarios. El control de patógenos por pesticidas, cuyo uso incontrolado agrava la cadena de producción y el deterioro ambiental. Objetivo: Determinar la capacidad antagonista de actinomicetos rizosféricos de papa nativa frente al Oomiceto Phytophthora infestans, causante del “tizón tardío”. Materiales y métodos: Muestras de suelo rizosférico de papa fueron colectadas en el distrito de Cabana– Región Ayacucho. Los actinomicetos fueron aislados en Agar Avena y Agar Almidón Caseína a 28°C por 7 días. Fueron caracterizados por producir enzimas extracelulares (EEC) y su capacidad antagónica frente al oomiceto mediante co-cultivos en Agar Avena, a través de porcentajes de inhibición. Cepas seleccionadas fueron sometidas a la detección del gen policétido sintasa (PKS), observaciones por Microscopía Electrónica de Barrido y su identificación molecular. Resultados: Se logró aislar 32 cepas de actinomicetos, siendo la mayoría productores de enzimas extracelulares como amilasa (100%) y celulasa (50%); crecen mejor a pH entre 7,5 - 8,5 y temperaturas de 25 – 30°C. Las pruebas de antagonismo indicaron que 71,9% de aislados tienen actividad inhibitoria dePhytophthora infestans; tres cepas seleccionadas presentaron el gen PKS, sobresaliendo la cepa CAB10-2, la cual logró alcanzar el 80,05% de inhibición al fitopatógeno. Conclusión: Ciertos actinomicetos rizosféricos de la papa son productores de compuestos bioactivos capaces de inhibir el desarrollo de Phytophthora infestans. Palabras claves: Actinobacterias, papa nativa, biocontrol de plagas, antagonismo

Vicerrectorado de Investigación y Posgrado (VRIP)en el Programa de Tesis de Pregrado(RR N° 06369-R-17) Universidad Nacional Mayor de San Marcos

158 Marine bacteria highly transcribe the proteorhodopsin gene during summer in the coastal waters of Antarctica

Bacterias marinas de aguas costeras antárticas transcriben en altos niveles el gen de la proteorodopsina durante el periodo estival

Jerónimo Cifuentes1, María Estrella Alcamán-Arias2,3, Tomás Alarcón-Schumacher1,4, Carlos Pedrós-Alió5, Beatriz Díez1,2. (1) Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile (2) Center for Climate and Resilience Research (CR)2, Universidad de Chile (3) Department of Oceanography, Universidad de Concepción (4) Max Planck Institute for Marine Microbiology (5) Programa de Biología de Sistemas, Centro Nacional de Biotecnología (CSIC) (Sponsored by Beatriz Díez )

Microbial proton-pumping rhodopsins are considered the simplest strategy among all phototrophs to produce energy from light. Proteorhodopsins (PR) are widespread among marine bacteria, and the most studied rhodopsins due to its ubiquitous presence in the ocean. However, in the Antarctic marine system the presence and transcription of PR-gene remains poorly explored. For the first time, we investigated the taxonomic affiliation and transcriptional activity of the PR-gene in marine bacteria during the austral summer in coastal waters from Chile Bay (Greenwich Island, Antarctica). We have identified using meta-omics and qPCR that the PR-bearing bacteria represented on average the 16.7% of the marine bacterial community during the summer. PR-bearing bacteria was represented by Proteobacteria and Flavobacteriia that were actively transcribing PR during day- and night-time. Moreover, we observed that marine bacteria transcribed PR-gene two times more during the day than at night. Our results show that PR could represent the main molecular strategy used by marine phototrophic bacteria to harvest sunlight energy at these coastal seawaters. This observation gives crucial information respect the prevalence of this mechanism in Antarctic seawater and the significance of this strategy to enter sunlight energy into the Antarctic biosphere.

Programa de Cooperación Internacional PCI: Project DPI20140044. Centro de Ciencia del Clima y la Resiliencia (CR)2: Project FONDAP 15110009

159 Mechanisms of DNA repair involved in resistance to UVB radiation at low temperatures

Mecanismos de reparación del ADN involucrados en la resistencia a la radiación UVB a bajas temperaturas

P. Cifuentes1, L Zapata2, R Gajardo-1, B. Parra1, M. Martínez1. (1) Departamento de Microbiologia, Ciencias Biológicas, Universidad De Concepción (2) Centro de Biotecnología, GreenCell SpA

La Radiación Ultravioleta (RUV) de tipo B (290–320nm) daña el ADN formado dímeros de ciclobutano pirimidina (CPD) y fotoproductos (6-4 PP). Actualmente se desconoce la capacidad de reparación del ADN de sistemas enzimáticos a bajas temperaturas. Es posible que el ambiente antártico expuesto a alta RUVB seleccione bacterias con enzimas capaces de reparar el ADN a bajas temperaturas. Esta propiedad también contribuiría a explicar la posible existencia de vida en mundos fríos. El objetivo de trabajo fue detectar enzimas de reparación del daño en el ADN funcionales a 5°C. Para esto, 36 cepas bacterianas antárticas y 32 patagónicas fueron expuestas a 180 Jm−2 de RUVB y se determinó la presencia de genes que codifican para enzimas de reparación: fotoliasas (phrB) y los operones, rulAB e impCAB. La funcionalidad de las fotoliasas a 5°C se evaluó incubando las bacterias bajo luz azul (470nm) para la fotoreactivación y por Dot Blot (Ab-KTM53) se cuantificaron los CPD. Dieciséis bacterias (20,8%) resistieron (<30% de sup) la RUVB pertenecientes a los géneros Pseudonomas, Acinetobacter, Arthrobacter, Deinococcus y Colwellia, de las cuales 4 presentaron el gen phrB. Se observó una supervivencia significativa de la cepa Colwellia GW185 bajo luz azul asociado a un menor número de CPDs. Los resultados sugieren que, si bien los genes estudiados tienen baja representación, los ambientes fríos son un buen modelo para estudiar los límites de reparación del ADN y otros mecanismos que protejan de la RUV, posicionando a los microorganismos como modelo astrobiológico idóneo.

160 Exploring the long-term dynamics of a plant-related synthetic microbial consortium under the influence of Arabidopsis thaliana root exudates with varying composition

Exploración de las dinámicas a largo plazo de un consorcio microbiano sintético cuando se ve influenciado por exudados de Arabidopsis thaliana en condiciones variables

Javier Cillero2,1, Daniela Ruiz2,1, Thomas Ledger2,1, Bernardo González 2,1. (1) Bioingenieria, Ingeniería y Ciencias , Universidad Adolfo Ibáñez (2) Center of Applied Ecology and Sustainability (CAPES).

There is a large number of microbial communities that influence the growth, health and/or the development of plants in a direct or indirect fashion. This important ecologic interaction between inter-kingdom members is a key research area to develop sustainable farming and bioremediation. The design and engineering of microbial consortia on plant-host related environments is focused on the development of robust microbial consortia that can be stable on a long-term basis. Plant-root exudates are a fundamental component to study the complex dynamics that govern this system. First, it allows the exploration of microbial interactions when exudates are used as the sole carbon source; second, their composition is highly dependent of the environment at which the plant is grown. This work proposes a bottom-up design in which a selected group of plant-related Beta-protobacteria are co-cultured on different kinds of collected exudates, in order to explore the microbial consortium ecologic interactions through network inference analyses. The bacteria are: Paraburkholderia phytofirmans (PsJN), Cupriavidus taiwanensis (LMG19424), Cupriavidus pinatubunensis (JMP134) and Cupriavidus metallidurans (CH34). All the selected bacteria belong to the Burkholderiales order and have shown a different type of interaction with plants. Our experiments on fourteen-day and twenty-one-day root exudates show that the microbial consortium abundance and viability is highly dependent on the exudate composition. Furthermore, in longer interaction times, the viability of the microbial consortium is significantly diminished when exposed to plant root exudates.

This work was funded by the FONDECYT 1151130, and the Center of Applied Ecology and Sustainability (CAPES) CONICYT PIA/BASAL FB0002.

161 Phylogenomic study of a novel rare actinobacteria and assessment of the antimicrobial activities of its extracts

Estudio filogenómico de una nueva actinobacteria rara y evaluación de la actividad antimicrobiana de sus extractos

Fernanda Paz Claverías Ramos2,1, Beatriz Cámara Herrera2. (1) Escuela de Graduados Facultad de Ciencias, Universidad Austral de Chile (2) Centro de Biotecnología Daniel Alkalay & Laboratorio de Microbiología molecular y Biotecnología Ambiental, Departamento de Química , Universidad Técnica Federico Santa María

Rare actinobacteria (RA) are defined as strains belonging to the Actinobacteria that are both difficult toisolate from the environment and to grow under laboratory conditions. RA are an interesting and less explored source of antimicrobial compounds.

Bioprospecting of Chilean marine environments has demonstrated the biodiversity of Actinobacteria that inhabits our littoral. Strain VN6-2 is a new RA, isolated from Valparaíso Bay. A low similarity of the 16S rRNA gene to VN6- 2, and several phylogenetic analyses showed that strain VN6-2 appears to represent a new taxon within the Nocardiopsaceae family. The aim of this study is to determine the taxonomic position of the strain VN6-2 using a genome-based approach and to assess its ability to produce antimicrobial compounds. A phylogenomic tree was constructed with the OrthoFinder program using the sequenced genome of strain VN6- 2 and the genome of all strains belonging to the Nocardiopsaceae family available in public databases. This study revealed that the strain VN6-2 forms a distinct branch in comparison to all other members of the family, positioning it as a possible novel genus.

Fermentation of strain VN6-2 was performed under different conditions, both on solid and liquid media. Secondary metabolites were obtained by liquid-liquid and solid-liquid solvent extraction. The antimicrobial activity of the different crude extracts was evaluated against model bacteria. Crude extracts showed inhibitory activity against Gram positive and Gram negative bacteria, obtaining better results with solid cultures.

Strain VN6-2 is a novel strain from the Nocardiopsaceae family and represent a potential source for drug discovery. FONDECYT N° 1171555, Anillo project ACT128172, Ph.D. fellowship CONICYT (FC)

162 Characterization of the microbial communities inhabiting sediments of fifteen lakes from the North of the Antarctic Peninsula

Caracterización de las comunidades microbianas que habitan los sedimentos de quince lagunas del norte de la Península Antártica Silvia Herminda Coria1, Déborah Colman1, Edgardo Hernández1, Susana Claudia Vázquez2, Walter Patricio Mac Cormack2,1. (1) Microbiología Ambiental, Instituto Antártico Argentino (2) NANOBIOTEC, UBA-CONICET

El norte de la Península Antártica presenta áreas costeras libres de hielo con cuerpos de agua oligotróficos cuyos sedimentos ponen en evidencia tanto el desarrollo de las lagunas como los cambios en el ambiente circundante. Adicionalmente, permiten el establecimiento de una amplia variedad de microorganismos que cumplen un rol relevante en los procesos geoquímicos y en el ciclado de la materia. El objetivo de este trabajo es caracterizar por primera vez un conjunto de lagunas antárticas desde el punto de vista de los ensambles microbianos presentes en sedimentos costeros superficiales.

Se colectaron muestras compuestas de sedimentos costeros superficiales de 15 lagunas correspondientes a los archipiélagos Shetland del Sur y James Ross. Se aisló el ADN genómico total. Se amplificó el gen del ARNr 16S y los amplicones se secuenciaron mediante Ilumina Miseq. El análisis bioinformático de los amplicones se realizó con QIIME, se usó la estrategia “de novo” para la construcción de OTUs y la asignación taxonómica se realizó con Silva 132 con un 97% de identidad.

El análisis de los taxones y su abundancia relativa mostró que las arqueas están presentes en todas las lagunas, predominando el phylum Thaumarchaeota. Se observó un gran predominio de las bacterias por sobre las arqueas, siendo los phyla bacterianos dominantes Proteobacteria (23%-51%), Bacteroidetes (7%-23%), Actinobacteria (4%-23%) y Acidobacteria (2%-7%). El análisis discriminante de todas las muestras basado en la estructura de las comunidades evidenció una clara segregación geográfica.

163 Unveiling the Biodiversity of Bacterial Spores in the Environment

Descubriendo la biodiversidad de esporas bacterianas en el medio ambiente

Andrea Corona1, Kang Soo Lee2, Stocker Roman2, Silvia Schintke3, Pilar Junier4. (1) Microbiologia, Ciencias , Neuchatel (2) ETH Zurich (3) University of Applied Sciences Western Switzerland (4) University of Neuchatel

Since the discovery of bacterial spores, research has been mainly focused on spores produced by members of four bacterial clades: Firmicutes, Actinomycetes, Cyanobacteria and Myxococcales. However, it is possible that sporulation or a similar morphogenetic process resulting in a highly resistant cell is more widely spread in nature, in which this survival strategy could be an adaptive response of microbial communities to adverse environmental conditions. This is suggested by the use of metagenomic tools using lysis-resistance to target these populations. Nevertheless, biases in the steps leading to metagenomics can result in low coverage of the less abundant taxa or underrepresentation of certain taxa. The utilization of a DNA extraction protocol with increased physical force to enrich the endospore fraction in combination with sequencing has enabled us to obtain genetic information about the most abundant spore-forming clades present in environmental samples, but more rare species might be overlooked. One approach to address this problem is the use of single cell Raman spectroscopy or Atomic Force Microscopy to sort individual spores. The aim of this study is to develop a method to generate single-spore genomic information to characterize the diversity of spore-forming clades from environmental samples. First, we will investigate the existence of a distinctive signal for bacterial spores by analyzing pure cultures containing spores and vegetative cells in model organisms. Once we have a specific Raman signal for bacterial spores, we will assess the suitability of Raman to sort bacterial spores from synthetic communities and later from natural communities.

Swiss National Science Foundation

164 Production of bioactive compounds induced by different culture conditions in thermophilic bacteria, isolated from the hydrothermal system of Lirima (Region of Tarapacá, Chile)

Producción de compuestos bioactivos inducidos por diferentes condiciones de cultivo en bacterias termófilas, aisladas desde el Sistema hidrotermal de Lirima (Región de Tarapacá, Chile)

Johanna Alejandra Cortes1, Vilma Perez2, Cristina Dorador 3, Karem Henriquez4, Veronica Molina 5, Martha Hengst6. (1) Laboratorio de Ecologia Molecular y Microbiologia Aplicada, Centro de Biotecnología y Bioingenieria (CeBiB), Facultad de Química y Farmacia, Facultad de Ciencias biomedicas, Universidad Catolica del Norte, Universidad de Antofagasta (2) Australian Centre for Ancient DNA, University of Adelaide, Australia (3) Laboratorio de Ecología y Complejidad Microbiana, Centro de Biotecnologia y Bioingegneria (CeBiB), Universidad de Antofagasta (4) Departamento de Ciencias y Tecnología de los alimentos, Laboratorio de Tecnología de los Alimentos, Facultad de Farmacia, , Universidad de Concepcion (5) Observatorio de Ecología Microbiana, Facultad de Ciencias Naturales y Exactas, Universidad Playa Ancha (6) Laboratorio de Ecologia Molecular y Microbiologia Aplicada, Facultad Química y Farmacia , Universidad Catolica del Norte

Se ha demostrado que la síntesis de compuestos bioactivos en bacterias constituye un mecanismode adaptación metabólica, expresado bajo condiciones de estrés ambiental, otorgándole la capacidad de aumentar su supervivencia en ecosistema con alta presión ambientales, como los ambientes poliextremos. Debido a la accesibilidad, estos ambientes han sido menos explorados; sin embargo, constituyen una fuente de interés para la búsqueda de nuevos compuestos bioactivos. Además, la presencia de múltiples estresores ambientales que actúan de manera simultánea y selectiva, constituyen inductores para la síntesis de metabolitos secundarios en los microorganismos que allí habitan.

En este estudio se analizaron dos cepas bacterianas termófilas aisladas desde el campo geotermal de Lirima, ubicado a 4200 msm en los Andes Centrales. Las condiciones a evaluar fueron: i) temperatura, ii) radiación UVC, iii) NaCl, iv) pH y v) contenido de materia orgánica. Desde, los cultivos bacterianos, se realizó extracción de compuestos por acetato de etilo y los extractos fueron analizados por HTLC-MS.

Los resultados demuestran que bajo diferentes tipos de estrés físico-químico, las bacterias producen compuestos diferentes. El peso molecular de los compuestos detectados fue comparado en bases de datos para establecer los compuestos naturales presentes en los extractos bacterianos. De ellos, 60% fueron no determinados lo que sugiere la alta novedad de metabolitos en este tipo de bacterias. Por otra parte, entre los identificados, se detectaron sustancias con actividad: antibacteriana, anticancerígena, antioxidante, entre otras; muchos de estos compuestos bioactivos de alto valor biotecnológico y farmacológico.

Fondecyt 1181773, 1140179, 1140356. PIA-Conicyt,FB0001 (CeBiB).

165 Evidence of microbial life in the deposits of nitrate north of chile: geochemistry, microbiology and metabolic activity

Evidencia de vida microbiana en los depositos de nitrato del norte de chile: geoquimica, microbiologia y actividad metabolica

Mayra Cortés1, Priscilla Avendaño2, Olga Encalada 2, Alex Echeverría 3, Guillermo Chong4, Cecilia Demergasso 2, Lorena Escudero 5. (1) Biotecnología , Ciencias del Mar y Recursos Biológicos , Universidad de Antofagasta (2) Centro de Biotecnología, Universidad Católica del Norte (3) Universidad Católica del Maule (4) Geología, Universidad Católica del Norte (5) Centro Científico y Tecnológico para la Minería (CICITEM) (Sponsored by Lorena Escudero González)

La presencia de minerales higroscópicos en los depósitos de nitrato/yodo (DNY), hacen que sea posible la existencia y proliferación de vida microbiana en estos ambientes. Por lo tanto, es de relevancia, demostrar que debido a la capacidad higroscópica de los minerales de nitrato es posible la presencia y sostenibilidad de microorganismos, reductores de nitrato presente en suelos del Desierto de Atacama, considerados únicos a nivel mundial. Bajo este contexto, se analizaron tres áreas definidas como DNY: ex oficinas Pissis-Savona (PS), Pampa Unión (PU) y Toco-Zapiga (TZ).

El análisis de secuenciación del gen ARNr16S (mediante illumina Myseq) determinó que las comunidades microbianas estaban dominadas por cuatro filos:Firmicutes , Proteobacteria, Actinobacteria y Bacteriodetes. La predominancia de estos filos estaría estrechamente relacionado a los minerales presentes (identificación mediante difracción de rayos-X), donde, la abundancia de Firmicutes estaría asociada a la mayor presencia de halita, mientras que Proteobacteria con nitratina. Además, las altas concentraciones de nitratina podrían incrementar la presencia de Actinobacteria y Bacteroidetes. Se obtuvieron cultivos reductores de NO3 que alcanzan un porcentaje de reducción de 56-68% (PS), 13-31% (PU) y 4.5-24% (TZ).

Los resultados de expresión génica permitieron la identificación y cuantificación de losgenes nosZ, nirK y nirS, confirmando la utilización del proceso metabólico de desnitrificación respiratoria y disimilatoria. La interacción entre las condiciones hostiles para la vida, la diversidad microbiana y la capacidad de reducción de nitrato observadas, aporta información relevante para una mayor comprensión de como se sustenta la vida microbiana en este tipo de ambientes, reservorios naturales del Desierto de Atacama.

Este trabajo fue financiado por el proyecto 11150686 de FONDECYT DE INICIACION de la Comisión Chilena de Ciencia y Tecnología (CONICYT).

166 Streptomyces huasconensis and Streptomyces altiplanensis: Two novel Streptomyces species from the poly-extreme ecosystem Salar de Huasco, producers of peptidic natural products

Streptomyces huasconensis y Streptomyces altiplanensis: Dos nuevas especies de Streptomyces del ecosistema poly-extremo Salar de Huasco, productoras de productos naturales peptídicos

Carlos Cortés-Albayay2,1, Barbara Andrews1, Juan Asenjo1, Cristina Dorador3, Imen Nouioui2. (1) Centro de Biotecnología y Bioingeniería, Universidad de Chile (2) School of Natural and Environmental Sciences, Newcastle University (3) Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta

Salar de Huasco is an athalassohaline and poly-extreme high altitude wetland at the Chilean Altiplano of the Atacama Desert, characterized for its high levels of solar radiation, aridity and high salinity of its soils. Our first culture- dependant study carried out on this ecosystem for the selective isolation of new Streptomyces species from arid soil samples of Salar de Huasco shoreline showed the presence of a high number of differentStreptomyces strains. Some of them successfully inhibited the growth of Gram-positive and Gram-negative bacteria and fungi pathogens and showed also cytotoxicity against hepatocellular carcinoma (HepG2) and mouse fibroblast cell lines (NIH-3T3). Two of the most promisorious Streptomyces strains demonstrated phenotypic, chemotaxonomic and genetic features that distinguished them from its closest type strain neighbours and were validly described as the novel alkalitolerant species Streptomyces altiplanensis HST21T and Streptomyces huasconensis HST28T.

Genome mining analysis for these new species revealed a high number of biosynthetic gene clusters (BGCs) including lasso peptides and lanthipeptides. S. huasconensis HST28T showed 4 lasso peptide BGCs of the classes II and IV of which a new class II lasso peptide was successfully detected in vitro by mean of a peptidogenomic approach based on a MS-guided genome mining method. This new lasso peptide named as huascopeptin showed the first seven- membered macrolactam ring motif structure, the smallest ring currently described in a lasso peptide. Our findings suggest that poly-extreme environments like Salar de Huasco are still promising sources for exploring novel and valuable bacteria producers of natural products with pharmaceutical potentials.

167 Computational Approaches for Characterizing Transposable Element Diversity with Applications to Cancer

Computational Approaches for Characterizing Microbiome and Transposable Element Diversity from Metagenomic Data with Applications to Cancer

Allison Kolbe1, Matthew Bendall1, Marcos Pérez-Losada2, Keith Crandall3. (1) Computational Biology Institute, George Washington University (2) Computational Biology Institute, Assistant Professor, George Washington University (3) Computational Biology Institute, Professor, George Washington University

Microbiome characterization has become an integral component to the study of a wide variety of disease and treatment approaches. Through the collection of metagenomic sequence data from DNA and/or RNA samples isolated from host individuals, effective microbiome characterization can identify pathogens, link diversity to disease state, characterize treatment effects, and identify drug resistant variants. Less studied are the transposable element contributions to the microbiome and their impact on disease. Unlike microbiome characterization where there are a number of useful and tested tools for characterization of diversity from 16S or metagenomic data, these tools do not identify transposable elements as they are typically not in reference databases. However, these elements can have a significant impact on human health. We describe a software package, TeleScope, that characterizes transposable elements in genomic data, maps those elements back to reference genomes, and identifies active mobile elements through the analysis of RNASeq data. We present results from both empirical studies and simulation studies characterizing the utility of our computational approaches with metagenomic data and compare our approach to other leading packages. We then demonstrate the utility of our approach to identify transposable elements associated with cancer. Specifically, we demonstrate the use of the characterization of human endogenous retroviral elements (HERVs) in relation to cancer by examining RNASeq data from The Cancer Genome Atlas (TCGA). We identify 56 upregulated and 48 downregulated HERVs significantly associated with head and neck cancer and map these HERVs back to the human genome.

This work has been supported by the NIH NCI award CA206488 and NCATS award UL1TR001876.

168 Production and composition of extracellular polymeric substances (EPS) in a culture of the terrestrial cyanobacterium Trichormus sp

Producción y composición de sustancias poliméricas extracelulares (EPS) en un cultivo de la cianobacteria terrestre Trichormus sp

Pablo Dahech1, Claudia Ortiz 1, Daniel Barros 1. (1) Biología, Química y Biología , Universidad de Santiago De Chile

Las cianobacterias son organismos procariontes fotoautotróficos productoras de sustancias poliméricas extracelulares (EPS) que pueden ser recuperadas desde el medio de cultivo líquido. Las EPS presentan un esqueleto de polisacáridos con grupos funcionales de propiedades aniónica y confieren a las cianobacterias resistencia a factores abióticos, además de adhesión y agregación celular. Esta capacidad de las EPS es responsable de la adhesión a las partículas del suelo, lo que permitiría disminuir la erosión eólica, tanto en suelos desérticos como degradados. Se ha estudiado la producción de las EPS en diferentes especies de cianobacterias y diversas condiciones de cultivo, como ausencia de nitrógeno combinado, presencia de NaCl o diferentes intensidades lumínicas, sin encontrarse una condición óptima única para la producción de estas. Cultivos de 30 días de la cianobacteria Trichormus sp. obtenidos desde suelos de la IV Región, presentaron alta producción de EPS en condiciones de cultivo basal (intensidad lumínica de 2150 lux, fotoperíodo de 16 horas luz:8 horas oscuridad y medio BG-11 pH 7 a 30°C). Para determinar las condiciones de máxima producción de EPS en Trichormus sp. se evaluó el efecto de NaCl (0.2, 0.4 y 0.6M) y ausencia de Nitrógeno combinado en el medio de cultivo, sin observarse diferencias estadísticamente significativas. Sin embargo, una intensidad lumínica de 6450 lux provocó un aumento significativo en la producción de EPS por Trichormus sp. Análisis de las EPS mediante GC-MS indicó que su esqueleto se compone principalmente de glucosa y fucosa siendo estos resultados únicos en cianobacterias chilenas.

FONDEF IDEA ID14I10151; FONDEF IT 16I10090; FONDEF IT17M10006.

169 Methane production using different residues from the poultry industry as a way to mitigate a serious environmental problem

Producción de metano utilizando diferentes residuos de la industria avícola como forma de mitigar un grave problema ambiental

Victoria De La Sovera1, Claudia Etchebehere1, Guillermo Zinola2. (1) Montevideo, Instituto de Investigaciones Biológicas Clemente Estable (2) NETUM SRL

Introducción Uruguay se propuso la meta de que un 30 % de los residuos agroindustriales y urbanos del país se utilicen para generar energía. Según un estudio realizado por la UdelaR y el proyecto Biovalor, la industria avícola produce unas 25.181 t/año de residuos sólidos orgánicos y efluentes los cuales son dispuestos en rellenos o en terrenos, conformando un foco significativo de contaminación del suelo y de los recursos hídricos del país. En este proyecto nos encontramos estudiando una alternativa para abordar este problema y asimismo producir energía de forma renovable a partir de la degradación anaerobia de los residuos de la industria avícola, tanto de forma individual como en co- digestión, produciendo dos biocombustibles gaseosos: metano e hidrógeno. Como forma de entender los procesos microbiológicos que ocurren, están siendo estudiadas en paralelo las comunidades microbianas seleccionadas en cada experimento a través de secuenciación masiva. Los resultados de la caracterización fisicoquímica de 7 residuos de la industria avícola mostraron una relación de sólidos volátiles/ sólidos totales mayor al 60% sugiriendo una alta biodegradabilidad. Por otro lado, se observaron distintas relaciones de C/N sugiriendo que su co-digestión podría ser favorable para equilibrar los nutrientes requeridos para la digestión anaerobia. Actualmente nos encontramos evaluando la digestión anaerobia de cinco de estos sustratos para la producción de metano: sangre, barros grasos, efluentes, gallinaza y cama de crianza. Los resultados obtenidos hasta el momento muestran el mayor potencial bioquímico de metano para los barros grasos con un valor de (350,2 ± 7,8) mL CH4/gSV sustrato.

170 Is it possible to isolate PAH-degrading bacteria from oily sludge using ligninolytic fungi?

¿Es posible aislar bacterias degradadoras de hidrocarburos policíclicos aromáticos de un barro petroquímico mediante la utilización de hongos ligninolíticos?

Natalia A. Di Clemente1, María S. Rodríguez Varela2, Mario C. N. Saparrat3, María T. Del Panno1, Lukas Y. Wick4. (1) Industrial Fermentations Research and Development Centre (CINDEFI), La Plata, Buenos Aires, Argentina. (2) School of Natural Sciences and Museum. National University of La Plata (FCNyM, UNLP), Argentina. (3) Institute of Plant Physiology (INFIVE), La Plata, Buenos Aires, Argentina. (4) Department of Environmental Microbiology, Helmholtz Centre for Environmental Research- UFZ. Leipzig, Germany.

Nowadays is considered that the success of biological strategies to remediate polluted sites with xenobiotics could be reached through microbial consortia. Several fungi such as ligninolytic ones can degrade and/or detoxify numerous recalcitrant compounds. According to the ability of mycelia from some fungi to act as highways for bacterial dispersion, we evaluated if ligninolytic fungi Coriolopsis rigida LPSC#232 and Grammothele subargentea LPSC#436, previously selected by their ability to grow and/or degrade pollutants, are able to isolate polycyclic aromatic hydrocarbons (PAH)-degrading bacteria from an oily sludge. We estimated fungal tolerance against different PAHs on agar medium and their hydrophobicity by contact angle. Bacterial isolation assay from oily sludge was evaluated in reversed minimal medium agar plate with wheat straw (MM), without PAH (control-I), MM with pyrene (PYR-II) and MM with PYR and dibenzothiophene (PYR+DBT-III).Colonized wheat straw by each fungus was put on sludge with a malt agar disc in the lid of upside-down placed plate. Uncolonized wheat straw was used as controls. All treatments were done in triplicates. After 45 days of incubation at room temperature and under dark conditions, bacterial colonies were detected only in association with LPSC#232/PYR+DBT. Bacteria was identified by morphology and 16S rRNA sequencing as Pseudomonas sp. Axenic assays showed its ability to degrade DBT on minimal medium. Cocultivation tests have been setted to corroborate the possible interaction between this bacterium and LPSC#232 to inquire if this consortium could be used in the context of bioaugmentation strategies to remediate polluted sites with oily sludges and other pollutants.

171 The Human Diets and Microbiome Initiative (THDMI): An Exploration of Dietary Patterns and their Influence in Microbiome Composition and Function under the Framework of The Microsetta Initiative

La Iniciativa de Dietas Humanas y el Microbioma (THDMI): Una Exploración de los Patrones Dietéticos y su Influencia en la Composición y Función del Microbioma en el Marco de la Iniciativa Microsetta

Edgar Diaz1, Daniel McDonald1, Se-Jin Song2, Muriel Derrien3, Aurélie Cotillard3, Consortium THDMI4, Sandrine Miller-Montgomery2, Liliana Jimenez3, Patrick Veiga3, Rob Knight1. (1) Department of Pediatrics, School of Medicine, University of California San Diego (2) Center for Microbiome Innovation, Jacobs School of Engineering, University of California San Diego (3) Danone Nutricia Research, Palaiseau, France (4) THDMI Consortium: Danone Nutricia Research (Julien Tap, Bénédicte Monnerie, Marion Poirel, Gérald Neveu, Christophe Sauce, Amira Pierruci-Lagha, Lauriane Raidot), Department of Pediatrics UC San Diego (Franck Lejzerowicz, Bryn Taylor, Justin Shaffer, Lisa

The Microsetta Initiative (TMI), the international expansion of the American Gut Project (AGP), is a highly collaborative effort with emphasis on global inclusion, standardization of technical practices, open-access policies for data and source code, as well as a utilization of modern molecular methodologies including shallow shotgun sequencing and HPLC-MS. Critically, the project is focused on engagement with underrepresented populations both at the local level (e.g., limited disposable income populations) and global scale (e.g., Latin America), and the expansion of the availability of population-specific microbiome references to improve the interpretation of regional studies.

As part of our growing efforts, TMI and Danone Nutricia Research have partnered to study the impact of dietary patterns on the human microbiome. The study will analyze thousands of samples from TMI participants through shotgun sequencing and study associations with their self-reported nutritional habits. Data collected will be made available to the scientific community as part of the TMI/AGP open access data policies, and will serve as an ever- growing reference data set for microbiome studies. Learn more about how to get involved at https://thdmi.org.

172 Bacterial communities related to the cultivation of the microalga Muriellopsis sp

Comunidades bacterianas asociadas al cultivo masivo de la microalga Muriellopsis sp

Daniela Diaz Mac-Adoo, Vladimir Avalos 1, Yannira Castillo1, Diana Fernandez1, Carlos Riquelme1. (1) Laboratorio de Ecologia Microbiana, Centro de Bioinnovación, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta

Las interacciones microalga-bacterias cubren toda la gama de relaciones simbióticas que se consideran posibles, sin embargo, la mayoría de estos tipos de interacciones son poco estudiadas.Existe evidencia de que las microalgas comprenden una amplia gama de interacciones con bacterias afectando sinérgicamente tanto en su fisiología como en su metabolismo, demostrando un efecto positivo entre la interacción microalga-bacterias relacionadas con el crecimiento de las microalgas y la producción de compuestos de interés. En el presente estudio, investigamos en cultivos cerrados de 1000 L, la dinámica en la composición de comunidades bacterianas de vida libre y adheridas de la microalga dulceacuicola, aislada en el norte de Chile, adaptada a crecer en agua de mar y productora de luteína: Muriellopsis sp. (MCH-35).Los resultados de metagenómica revelaron que las comunidades bacterianas de vida libre y adheridas, muestran diferencias en abundancia relativa en las diferentes etapas de la curva de crecimiento de la microalga. Con respecto a las comunidades de vida libre, se observó la dominancia del género Balneola y Marinobacter en todas las etapas de crecimiento, sin embargo, Balneola también se hace dominante en las comunidades adheridas mostrando una alta abundancia en etapa exponencial de la curva de crecimiento de la microalga. Estos resultados pueden entregar aproximaciones relevantes para el cultivo a gran escala de esta microalga con el fin de obtener compuesto de alto interés comercial.

“MEJORAMIENTO Y DESARROLLO BIOTECNOLÓGICO DE LA PRODUCCIÓN DE MICROALGA CLORÓFITA Muriellopsis sp., PARA LA OBTENCIÓN COMPUESTOS ANTIOXIDANTES EN EL NORTE DE CHILE” FONDEF: ID14I10110

173 Persistence of corrosive microorganism to THPS in oil industry

Poblaciones persistentes al THPS con potencial de actividad corrosiva en la industria petrolera

Lina Edith Dominici1,2, Marisa Viera2, María Teresa Del Panno1. (1) CINDEFI (UNLP-CONICET) (2) CIDEPINT (CICPBA-CONICET)

La corrosión influenciada microbiológicamente (MIC) es un proceso donde los microorganismos pueden iniciar, facilitar o acelerar la corrosión. Los microorganismos reductores del sulfato, bacterias y arqueas, son relevantes en los daños por MIC. El sulfato de tetrakis(hidroximetil) fosfonio (THPS) es un biocida usado para el control de la MIC en la industria petrolera. El objetivo del trabajo fue evaluar la eficacia del THPS en sistemas batch de cultivos conteniendo agua de tanque de almacenamiento, crudo y dos cupones de acero al carbono SAE 1010. Se realizaron dos sistemas, con THPS (200ppm) y sin THPS (controles) que fueron incubados 60 días en anoxia. La presencia de THPS produjo un significativo descenso de la población bacteriana planctónica medida por qPCR del gen 16S rRNA en los primeros días del tratamiento. Luego de 8 días, la concentración del biocida ya no fue detectada. Al finalizar el ensayo, la densidad microbiana planctónica en ambos sistemas fue similar. Sin embargo, el análisis de diversidad del gen del 16S rRNA (Illumina-Miseq) de bacterias y arqueas evidenció una comunidad microbiana diferente en presencia del biocida, con predominio de miembros de géneros asociados a procesos de biocorrosión y un incremento en la riqueza de arqueas. Interesantemente, luego de 30 días en presencia de THPS la densidad de biofilm fue significativamente mayor, sin observarse cambios en las propiedades electroquímicas. Los resultados sugieren que el efecto inicial del THPS produjo la selección de una comunidad resiliente a largo plazo con potencial de biocorrosión.

174 Enzymatic characterization of iprodione-degrading bacteria, isolated from a biopurification system

Caracterización enzimática de cepas bacterianas degradadoras de iprodiona, aisladas desde un sistema de biopurificación

Pamela Donoso-Piñol1,2, Bárbara Leiva2, Claudio Lamilla2, María Cristina Diez2,3. (1) Doctorado en Ciencias de Recursos Naturales, Facultad de Ingeniería y Ciencias, Universidad de La Frontera (2) Centro de Excelencia en Investigación Biotecnológica Aplicada al Medio Ambiente, Facultad de Ingeniería y Ciencias, Universidad de La Frontera (3) Departamento de Ingeniería Química, Facultad de Ingeniería y Ciencias, Universidad de La Frontera

Iprodiona, es un fungicida utilizado para combatir enfermedades fitopatógenas, debido a su toxicidad, seha prohibido su uso en diferentes partes del mundo, pero en Chile aún es permitido. Los sistemas de biopurificación (SBP) se desarrollaron para evitar la contaminación puntual por plaguicidas, siendo una tecnología basada en la degradación microbiana de contaminantes como iprodiona. Se han reportado cepas bacterianas aisladas desde suelos contaminados y SBP capaces de degradar este plaguicida. Sin embargo, pocos trabajos reportan enzimas involucradas en la degradación de iprodiona. Con lo anterior, el objetivo de este trabajo fue caracterizar la actividad enzimática de bacterias aisladas desde un SBP con la capacidad de degradar iprodiona. Se seleccionaron seis cepas bacterianas aisladas de la biomezcla de un SBP con la capacidad de degradar iprodiona comercial a 50 mg∙L-1 por 48 h a 28 °C y agitación 130 rpm, cuantificando su concentración por HPLC. Las cepas fueron caracterizadas fenotípica y molecularmente (16sDNAr), además se evaluó la actividad enzimática exo e intracelular. Los resultados mostraron que las seis cepas estudiadas pertenecen a las familias de Protobacterias. Además, poseen una alta capacidad de degradación de iprodiona, siendo superior al 96%. Las cepas, muestran diversidad fenotípica y enzimática, destacando las enzimas arilamidasas, relacionadas con la degradación de plaguicidas de similares características. En conclusión, las cepas bacterianas poseen una alta capacidad de degradación de iprodiona, con actividades enzimáticas de interés para la degradación de este plaguicida.

FONDECYT 1161481, CONICYT/FONDAP/15130015, DIUFRO-2019

175 The catabolic potential of the hydrocarbonoclastic Pseudomonas stutzeri strain DN36

El potencial catabólico de la bacteria hidrocarbonoclástica Pseudomonas stutzeri cepa DN36

Flavia Dorochesi1, Francisco Salvà-Serra2, Edward R. B. Moore2, Valentina Méndez2, Roberto Durán2, Michael Seeger2. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química , Universidad Técnica Federico Santa María, Valparaíso, Chile (2) Culture Collection University of Gothenburg (CCUG) & Department of Infectious Diseases, University of Gothenburg, Gothenburg, Sweden

Pseudomonas stutzeri DN36 is a hydrocarbonoclastic bacterium isolated from a polluted soils from the Valparaíso Region, Chile. This bacterium has been applied in bioaugmentation processes for the remediation of hydrocarbons- polluted soils at pilot scale. The aim of this study was to determinate the hydrocarbons catabolic potential in P. stutzeri DN36. The bacterium was grown on several hydrocarbons (aliphatic and aromatic) as sole carbon source. The genome was completely sequenced using SMRT sequencing technique (Pacific Biosciences), assembled with SPAdes v.3.11.1 and annotated using PROKKA software. The identification of catabolic genes and their genomic context was carried out through homology-based analysis using Blast. Strain DN36 is able to grow in BHB minimal medium on hexane, octane, benzoate and phenol as sole carbon sources at 30°C. The highest growth was observed on octane. The genome is organized in one circular chromosome of 4,2 Mb with a 64,3% G+C content and possesses 4,022 coding sequences. Catabolic pathways of aliphatic hydrocarbons (alk and cyp genes), benzoate, phenol and tyrosine was identified. Due to the key role of oxygenases in the degradation of hydrocarbons, the classification of the alpha subunits of oxygenases in the genome was carried out. This study indicates that Pseudomonas stutzeri DN36 is able to grow in aliphatic and aromatic hydrocarbons as sole carbon sources.

CONICYT PhD 21171489/2017 (FD) fellowship, CONICYT PIA Anillo GAMBIO ACT172128 & Fondecyt 1151174 (MS).

176 Genome-guided physiological characterization of the hydrocarbonoclastic marine bacterium Alcaligenes aquatilis QD168 reveals a robust adaptive response to multi-stressor environments

Caracterización fisiológica guiada mediante el genoma de la bacteria marina hidrocarbonoclástica Alcaligenes aquatilis QD168 revela una robusta respuesta adaptativa a medio ambientes con múltiples estresore

Roberto Durán1, Valentina Méndez1, Bárbara Barra-Sanhueza1, Francisco Salvà-Serra2, Daniel Jaén-Luchoro2, Edward R.B. Moore2, Michael Seeger1. (1) Departamento de Química, Química, Universidad Técnica Federico Santa María (2) Sahlgrenska University Hospital, Culture Collection University of Gothenburg

Crude oil-polluted marine sediments are multi-stressor environments were the presence of hydrocarbons, as well as nutrient and salinity fluctuations portray a crucial role in bacterial fitness. Alcaligenes aquatilis QD168 is a hydrocarbonoclastic marine bacterium isolated from crude-oil marine sediment of the Quintero Bay, Valparaíso Región, Central Chile able to grow on diesel, nhexadecane and benzene. A complete genome sequence was obtained by PacBio sequencing, achieving a 4.32 Mb circular chromosome. The aims of this study were to identify the genetic determinants involved in the survival of A. aquatilis QD168 to abiotic stressors and to characterize strain QD168 capacity to overcome hydrocarbon pollution, salinity fluctuation and oxidative stress response. Seven central pathways (e.g., cat and lig genes) and 16 peripheral pathways/reactions (e.g., dmp and ben genes) for aromatic compound catabolism were identified in strain QD168 genome. Strain QD168 is able to grow on 14 compounds (e.g., benzene, phenol, nicotinate, cinnamate) corroborating some of the pathways identified previously. Genes encoding the short-chain-length polyhydroxyalkanoate biosynthetic pathway (pha genes) were detected. Genes coding for the biosynthetic pathway of the osmoprotectant, ectoine/5hydroxyectoine (ect genes) were found in QD168 genome, while QD168 strain can tolerate 010% w/v NaCl supplementation in R2A assays. Genes (30 genes) involved in oxidative stress response were identified in QD168. Oxidative stress response of strain QD168 to H2O2 and paraquat was characterized, demonstrating that A. aquatilis QD168 is notably more resistant to paraquat. The physiological adaptation of A. aquatilis QD168 to environmental stressors may be exploited for bioremediation of oil-polluted marine sites.

Beca CONICYT Magíster Nacional 2016-22162307, (RED), Proyecto FONDECYT 1151174 (MS), Proyecto Anillo GAMBIO ACT172128 (MS, VM, RD), USM grants.

177 Biological activity of external membrane vesicles (OMV) of Vibrio ordalii in vitro

Actividad biológica de Vesículas de membrana externa (OMV) de Vibrio ordalii in vitro

M., Echeverría-Bugueño3,1, D. Tapia-Cammas,3,2, R Irgang3,2, R. Avendaño-Herrera.3,2. (1) Instituto de Química, Instituto de Química, Pontificia Universidad Católica De Valparaíso (2) Laboratorio de Patología de Organismos Acuáticos y Biotecnológia Acuícola, Ciencias de la Vida, Universidad Andrés Bello (3) (INCAR), Interdisciplinary Center for Aquaculture Research

Vibrio ordalii es un patógeno marino que genera vibriosis en peces, especialmente salmones y truchas. En nuestro país la cepa nacional ha generado grandes pérdidas en la industria salmonicultora, especialmente en el año 2014. Considerando la necesidad de disminuir el uso de antibióticos en ambientes marinos se deben buscar nuevas alternativas para controlar las infecciones bacterianas. Un mecanismo de interés que ha tomado relevancia en los últimos años es el generado por las vesículas de membrana externa u OMV por sus siglas en inglés. Estas vesículas presentan actividades diversas, como citotóxica, de transporte e inmunosupresoras por lo que han sido destacadas como posibles nuevos target farmacológicos. En nuestra investigación se ha comprobado por microscopía de barrido la producción de OMV por parte de la cepa nacional de Vibrio ordalii, se han aislado y purificado comprobando estos hechos por DLS y espectroscopía RAMAN. determinado su actividad bioquímica de tipo hemolítica en placas de agar sangre, comparado los perfiles proteícos mayoritarios por SDS-PAGE y determinado la actividad citotoxica in vitro en línea celular CHSE-214 siguiendo la liberación de LDH y visualizando el tipo de daño celular con microscopía óptica. Los resultados indican que las vesículas purificadas presentan una citotoxicidad mayor frente a la bacteria y que el daño celular es provocado en horas tempranas por parte de las vesículas tardandose solo 48 horas respecto a las 148 que se requieren para la bacteria considerando una MOI 10.

Beca Doctoral Conicyt Nº 21180737 Conicyt FONDAP Nº 15110027 Conicyt FONDECYT Nº 1150695

178 Characterization of viral communities in the high-altitude wetland, Salar de Huasco, Chile

Caracterización de comunidades virales en el humedal altiplánico, Salar de Huasco, Chile

Yoanna Eissler1, Cristina Dorador5,2, Verónica Molina3, Martha Hengst5,4. (1) Instituto de Química y Bioquímica, Facultad de Ciencias, Universidad de Valparaíso (2) Laboratorio de Complejidad Microbiana y Ecología Funcional, Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (3) Programa de Biodiversidad y Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha de Ciencias de la Educación (4) Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte (5) Centre for Biotechnology and Bioengineering

El altiplano chileno se caracteriza por presentar ecosistemas diversos y sometidos a condiciones extremas, principalmente de temperatura y salinidad. Entre estos ecosistemas, se encuentra el Salar de Huasco a 3.800 m s.n.m., el cual presenta una comunidad microbiana de bacterias y archaeas abundante y muy diversa. El objetivo de este estudio fue determinar la abundancia y diversidad de las comunidades virales, así como de sus potenciales hospederos microbianos. En este trabajo se examinaron dos sitios denominados H3 y H0 en noviembre del 2015. Se colectaron datos fisicoquímicos y se tomaron muestras para la determinación de la abundancia de partículas virales y picoplancton. Además, se obtuvieron concentrados virales a través de ultrafiltración por flujo tangencial. Estos se procesaron de acuerdo a un protocolo específico para amplificación de virus ADN y luego se secuenciaron (HiSeq system, Illumina). Los sitios H3 y H0 mostraron una conductividad de 580,7 y 566,3 µS cm-1, respectivamente. La abundancia viral fue de 1,3 y 2,5 x106 VLP ml-1 y de picoplancton de 5,3 y 2,1 x105 células ml-1, con razones de virus a picoplancton de 2,3 y 12,1 para H3 y H0, respectivamente. Las secuencias dominantes en los metagenomas fueron de virus del orden Caudovirales, familias Myoviridae, Podoviridae y Siphoviridade, los cuales infectan a bacterias y archaeas. Otras familias observadas fueron Phycodnaviridae, Microviridae, Iridoviridae y Caulimoviridae. Este estudio presenta la relevancia de las comunidades virales como patógenos y potenciales agentes de transmisión de genes entre las comunidades microbianas en ambientes con condiciones extremas.

Proyectos Fondecyt #1181773 “Microbial complexity gradients in polyextreme environments” y #1171324 “Nitrite loop in aquatic ecosystems, an example of environmental microbiome cooperation on nitrogen cycle”.

179 Comparison of bacterial microbioma present in different oral microambients in patients with oral squamous cell carcinoma

Comparacion del microbioma bacteriano presente en distintos microambientes orales en pacientes con carcinoma escamocelular oral

Alveiro Erira Tupaz1, Adriana Garcia2, Fredy Gamboa2, Andrey Moreno3, Andres Chala4, Gloria Moreno2. (1) Ciencias Básicas, Ciencias, Pontificia Universidad Javeriana (2) Salud Oral, Odontología, Pontificia Universidad Javeriana (3) Patología, Medicina, Pontificia Universidad Javeriana (4) Cirugía, Medicina, Universidad De Caldas

El carcinoma oral de células escamosas (OSC) ocupa el sexto lugar de cáncer más frecuente en el mundo, los factores de riesgo incluyen bacterias. Los estudios en microbiota se han realizado mediante secuenciación del gen 16S, encontrando diferencias significativas en diversidad y abundancia en muestras tumorales. Actualmente no se cuenta con biomarcador microbiológico en OSC, debido a la diversidad y complejidad en los distintos microambientes orales. Se comparó el metagenoma oral de personas con OSC (10 tejido tumoral, 10 de saliva y 10 de placa bacteriana) con el de personas sanas (10 de saliva y 10 de placa bacteriana). Se realizó extracción de ADN, se evaluó cantidad y calidad, y se secuenciaron por ilumina MiSeq. Se realizaron análisis bioinformáticos y estadísticos para limpieza de datos, asignación taxonómica, construcción de perfiles, validación de patogenicidad y un análisis discriminatorio entre microambientes tumorales y controles con Trimmomatic, FastQc, Kraken Aligner, Krona y R-studio. Encontramos en promedio 30 Phyla bacterianos, 600 géneros y 1250 especies; 4 géneros específicos de tumor, 5 géneros específicos de placa de controles. En saliva, 20 géneros fueron específicos de pacientes con OSC y 41 géneros se encontraron únicamente en controles. 44 especies bacterianas estaban incrementadas en placa dental de pacientes y 8 en placa dental de controles. También se encontró 36 especies bacterianas incrementadas en saliva de pacientes.El Microbioma bacteriano oral es más diverso en placa dental que en saliva, y podría estar asociado a procesos carcinogénicos y saludables.

180 Biofilm formation enhanced current production in an electrogenic and genetically modified Cupriavidus metallidurans strain

La formación de biopelículas incrementa la produccion de electricidad en una cepa electrogenica y geneticamente modificada deCupriavidus metallidurans

Anna Espinoza-Tofalos1, Pablo Alviz-Gazitúa 2, Nicolas Guiliani3, Andrea Franzetti1, Michael Seeger 2. (1) Department of Earth and Environmental Sciences, Università degli Studi di Milano-Bicocca (2) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Quìmica, Universidad Técnica Federico Santa María (3) Departamento de Biología, Facultad de Ciencias, Universidad de Chile

Bioelectrochemical Systems (BES) are systems based on the connection between microbes (named as electroactive bacteria or exoelectrogens) and electrodes. Cupriavidus metallidurans CH34 is a model heavy metal resistant and hydrocarbonoclastic strain, whose exoelectrogenic activity has been recently described. Biofilm formation by electroactive microorganisms is essential for direct electron transfer. Bacterial biofilm formation is mediated by the second messenger bis-(3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP). In general, high levels of c-di- GMP promote bacterial biofilm formation through extracellular polymeric substances (EPS) production. In this study, the electrogenic activity of C. metallidurans pJB:pleD*, compared with the parental strain, was investigated. C. metallidurans CH34 was genetically modified in order to increase the levels of intracellular c-di-GMP levels. The increase in c-di-GMP levels in strain C. metallidurans pJB:pleD*promoted biofilm formation and EPS production. Current densities in the BES inoculated with C. metallidurans pJB:pleD* and the parental strain reached ~80 mA/ m2 and ~15 mA/m2, respectively. The expression of genes that encode for specific proteins associated to exchange electrons with the electrode were studied by RT-qPCR. In addition, the structure of the biofilm on the electrode surface was characterized by scanning electron microscopy. These results support that an increase in biofilm formation, improved current formation byC. metallidurans pJB:pleD* through changes in their electroactive components. These improved BES may have interesting biotechnological applications.

Anillo GAMBIO ACT172128, Fondecyt and USM grants, Italian National Institute for Insurance against Accidents at Work (INAIL) in the framework of BRIC 2016

181 Dynamics of Archaea communities in soda lakes from the Brazilian Pantanal

Dinámica de las comunidades de Archaea en lagos de soda del Pantanal brasileño

Yara Feitosa1, Fernanda Asselta1, Thierry Pellegrinetti1, Juliana Costa1, Marli Fiore1, Siu Tsai1, Fabiana Paula1. (1) Centro de Energia Nuclear na Agricultura, Universidade de São Paulo

The Pantanal is the largest tropical wetland in the world and has about 600 soda lakes, that are considered extreme environments due to its elevated pH, salinity and NaHCO3 content. Information about the microbial communities in these lakes are incipient, especially those related to the Archaea domain. Here, we provide the first insights into the taxonomic composition and dynamic of archaeal communities in these ecosystems. We used metagenomic sequencing to analyze phytoplanktonic samples collected during dry and wet seasons from three distinct soda lakes in the region of Nhecolândia, Brazil. The green water lake (GWL) is characterized by permanent cyanobacterial bloom, while the black water lake (BWL) and crystalline water lake (CWL) have low nutrient concentration. Signatures from five archaeal phyla (Crenarchaeota, Euryarchaeota Korarchaeota, Nanoarchaeota, Thaumarchaeota) were identified across all lakes. Methanomicrobia was the most abundant class, followed by Halobacteria and Thermoplasmata, regardless of season and lake type. Our data suggest that seasonality has no effect on archaeal abundance in GWL. An increased abundance of Thaumarchaeota taxa was observed in BWL during the wet season, when compared to the other lakes. Interestingly, this lake also presented higher concentration of nitrite and nitrate. The redundancy analysis showed that more than 76% of the variation in archaeal composition was explained by chemical and physical parameters of the water. Total dissolved nitrogen and ammonium were the main factors explaining the sample distribution. Ongoing investigations are exploring the interactions of this microorganisms with biotic andabiotic factors, besides their role in nutrient cycling.

This research was supported by the São Paulo Research Foundation (FAPESP) and Coordination for the Improvement of Higher Education Personnel (CAPES).

182 The small eukaryotes of great tropical African lakes: biodiversity, abundance and importance in the food web

Los pequeños eucariotas de los grandes lagos tropicales africanos: biodiversidad, abundancia e importancia en la red trófica

Paulina Fermani1, Sebastian Metz1, Vanessa Balague2, Jean Pierre Descy3, Cédric Morana4, Ramiro Logares2, Ramón Massana2, Hugo Sarmento5. (1) Laboratorio de Ecología y Fotobiología Acuática, Instituto Tecnológico de Chascomús (INTECH-UNSAM-CONICET) (2) Institute of Marine Sciences (ICM), CSIC, Passeig Marítim de la Barceloneta, Barcelona, Catalonia, Spain (3) Laboratory of Freshwater Ecology, URBE, Department of Biology, UNamur, Belgium (4) Department of Earth and Environmental Sciences, Katholieke Universiteit Leuven (KU Leuven), Belgium (5) Universidade Federal de São Carlos, Departamento de Hidrobiologia, São Carlos, Brazil

The lakes of East African Valley are unique natural resources that are heavily utilized by their bordering countries. Due to their large size, ecosystem function is dominated by pelagic processes, where microorganisms are key components of aquatic communities. Exploitation of resources, eutrophication and climate change is altering the diversity and function of these lakes and their microbial diversity is barely known, despite their importance in biogeochemical cycles. We investigated the community composition of small eukaryotes (< 5 µm) of four African great lakes (Kivu, Edward, Albert and Victoria) by sequencing the V4 region of 18S rRNA gene. Moreover, in the meromictic Lake Kivu, one of the largest methane reservoirs on Earth, two stations (Gisenyi and Ishungu) were sampled over vertical profiles. We obtained 779 operational taxonomic units (OTUs) (99% clustering similarity) grouped in 9 high-rank supergroups and 58 taxonomic classes, being Alveolata (31%), Opistokonta (20%) and Stramenopiles (17%) the most represented supergroups. In surface waters, microeukaryotes abundances differed amongst lakes according to physical and chemical variables. The cluster analysis (Bray-Curtis dissimilarity index) showed Lake Victoria, which presented the lowest abundances and the greater species richness, as the most distinct. Lake Kivu exhibited the highest abundance at 15 m in both sites, but differed in composition. Overall, we found many OTUs (40.6%) with low similarity (< 90%) with reported sequences in public databases, mostly in deep anoxic waters of Lake Kivu, suggesting a high potential for novel diversity, probably associated with their particular physical and chemical characteristics.

EAGLES (East African Great Lakes), Belgian Federal Science Policy Office (BELSPO), Fonds de la Recherche Scientifique (FNRS), FRFC (Fonds de la Recherche Fondamentale Collective) n° 2.4515.11F and MICKI (Microbial diversity and processes in Lake Kivu)

183 Probiotic administration changes fecal microbiota of dairy calves

La administración de probióticos genera cambios en la microbiota fecal de terneros de lechería

Sofía Fernández1, Pablo Zunino1. (1) Dpto de Microbiología, Instituto de Investigaciones Biológicas Clemente Estable

El uso de microorganismos nativos con capacidad probiótica puede ser una herramienta alternativa para el tratamiento y prevención de diversas patologías animales, como la diarrea neonatal de terneros. Las cepas TP1.3B (Lactobacillus reuteri) y TP1.6 (Lactobacillus johnsonii) fueron administradas en forma oral a terneros de lechería en dos ensayos in vivo, uno en primavera y otro en otoño. En cada ensayo se emplearon tres grupos de cinco animales (un grupo control, uno tratado con TP1.3B y otro con TP1.6). La administración empezó a los 5-8 días de vida (día 0) y consistió en una dosis diaria (1x10^9 UFC) durante 10 días consecutivos. Se realizó el seguimiento de los animales por un mes (score fecal diario e índice de consistencia fecal) y se analizó la microbiota fecal por secuenciación masiva del gen ribosomal 16S en los días 0, 10 y 21. En ambos ensayos, el score fecal diario y el índice de consistencia fecal de ambos grupos tratados fue significativamente menor que el control. Mediante las técnicas de PERMANOVA, DESeq2, PICRUSt2, LEFse y modelos mixtos se observaron diferencias específicas en la microbiota de los grupos tratados y el grupo control. Una de ellas fue la disminución de los géneros Escherichia/Shigella en uno de los ensayos. A su vez se establecieron patrones asociados a los cambios temporales que sufre la microbiota del tracto gastrointestinal relacionados con la transición natural desde monogástricos a rumiantes. Estos resultados indican que ambas cepas se presentan como promisorias para utilizarse como probióticos para terneros de lechería.

Este trabajo fue financiado con fondos de INIA (FPTA 325) y ANII (beca de Doctorado).

184 Characterization of a PAH chronically contaminated-soil using a metagenomic approach

Caracterización de un suelo crónicamente contaminado con PAH utilizando un enfoque metagenómico

Sabrina Festa1, Florencia Layun1, Adán Ramirez Rojas 2, Juan Manuel Anzola2, Maria Mercedes Zambrano2, Bibiana M Coppotelli 1, Irma S Morelli1. (1) Laboratorio de Biodegradación Microbiológica de Hidrocarburos, CINDEFI (CONICET-UNLP) (2) Corporación CorpoGen

El objetivo de este trabajo fue caracterizar un suelo contaminado para conocer su composición, la química y concentración del contaminante y las características microbiológicas, incluyendo un enfoque metagenómico para comprender de las redes genéticas y metabólicas presentes en ese suelo. El suelo utilizado (IPKn) se obtuvo de las inmediaciones de un complejo industrial petroquímico, que provenía de una planta de tratamiento por landfarming de un residuo de pileta API (American Petroleoum Institute). La caracterización edafológica mostró una clase textural franco, relación C:N:P 0,23:0,01:1, pH 8,2 y 9,88% de materia orgánica. La concentración de hidrocarburos totales (extracción acetona/hexano, GC-FID) fue de 608,0 ± 50,4 mg.kg-1 de suelo seco, mayor concentración de hidrocarburos aromáticos que alifáticos. La cuantificación (qPCR) del gen 16S rRNA mostró valores de 10 copias por gramo de suelo seco, mientras que el gen PAH-RHDα GN presentó valores solo dos órdenes de magnitud menor. Se encontró actividad para la enzima lipasa, fosfatasas y ureasa. En el análisis preliminar de la secuenciación del metagenoma del suelo (Illumina MiSeq) se lograron anotar proteínas con función conocida y se encontró la presencia predominante de filo Actinobacteria (MG-RAST). El análisis funcional mostró que el 5,39% del metabolismo de xenobióticos se direccionaba a la degradación de PAH. Las enzimas encontradas (EC 1.14.1.27 y EC 1.13.11-) están presentes en varios pasos de las rutas de fluoreno, antraceno, fenantreno, pireno y benzo(a)pireno. El suelo IPKn mostró una comunidad altamente seleccionada o especializada en la degradación de hidrocarburos como consecuencia del fuerte impacto de la contaminación sufrida.

UNU-BIOLAC

185 Functional and structural resilience in a full-scale sludge digester transiently submitted to sub- mesophilic temperature

Resiliencia funcional y estructural en un digestor de lodos a escala industrial sometido de forma transitoria a temperatura sub-mesófila

Oscar Franchi1,2, Delphine Conteau3, Olivier Chapleur4, Rolando Chamy5,1, Gilberte Gabal3, Pablo Kroff3, Laurent Mazeas4. (1) Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile (2) Universidad Adolfo Ibañez, Viña del Mar, Chile (3) Suez-CIRSEE, France (4) Irstea, France (5) Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile

Anaerobic digestion of sewage sludge represents a well established technology. Nevertheless, current knowledge on biomethanation at low temperature in full-scale digesters is scarce and little is known regarding the microbial community changes ocurring on these systems during low temperature operation and how this changes affects the process performance. Based on this, a full-scale experiment was carried out in an urban WWTP where a 3,000 m3 sludge digester was subjected to a transient temperature decrease from 35 °C to 25 ºC. The digester performance was monitored and the microbial dynamics was studied by 16S rRNA amplicon sequencing analysis and compared with a control digester operated in parallel. The temperature disturbance caused a transient decrease in methane production by 16% and also lowered the system´s akalinity. Microbial analysis revealed that low temperature triggered a change in the microbial community structure that was resilient once the normal temperature was restored. Low temperature operation affected negatively the abundance and potential activity of the dominant bacterial OTUs, Candidatus cloacimonas and Rikenellaceae. In addition, correlation test confirmed that activity of these dominant OTUs correlated positively with COD removal, suggesting that drop in methane production in the system due to low temperature was a consequence at some extent by the activity decrease of these bacteria. On the other hand, ecological network analysis showed that the digester submitted to low temperature displayed a less connected network in comparison to the control digester thus indicating that low temperature negatively affects the interactions of the microbial community.

Proyecto código ANR-16-CE05-0014

186 Temperatura-dependencia en la mineralización del carbono asociado a carcasas de zooplancton en hundimiento

Temperature dependence of carbon mineralization associated with sinking zooplankton carcasses

Belén Franco-Cisterna1, Peter Stief1, Ronnie N. Glud2,1. (1) Nordcee, Departament of Biology, Faculty of Science, University of Southern Denmark (2) Department of Ocean and Environmental Sciences, Tokyo University of Marine Science and Technology

It is estimated that one third of marine zooplankton are dead specimens. These zooplankton carcasses are rich in labile organic carbon compounds which can be microbially degraded in the water column, become part of the vertical particle flux, or reach the seabed to be further degraded or buried in the sediments. In this study, carbon mineralization in sinking zooplankton carcasses was quantified as aerobic microbial respiration associated with the cosmopolitan copepod Acartia tonsa at incubation temperatures between 4 and 20°C. Microbial respiration rates associated with -1 -1 A. tonsa ranged between 0.4 and 5.3 nmol O2 carcass h , were positively correlated with temperature, and gradually declined during the incubation. Up to 90% of the total carbon content of the copepod carcasses was mineralized during 25 days of oxic incubations and hence represents labile organic carbon. Carcass degradation stimulated also microbial respiration activity in the surrounding seawater and promoted growth of free-living bacteria, reaching peak abundances that were ca. 100 times higher than in control incubations without carcasses. Based on our respiration rates and assuming a sinking speed of 100 m d-1, the labile organic carbon of A. tonsa carcasses is estimated to be mineralized in the first 1000 m at 20°C and 5000 m at 4°C. At high temperature, sinking zooplankton carcasses are thus an important source of organic carbon for pelagic microbes. At low temperatures, however, zooplankton carcasses may reach the deep ocean before degradation is completed and potentially feed benthic food webs or contribute to carbon export in the oceans.

This study was funded by the HADES-ERC Advanced Grant (No. 669947) and Beca de Doctorado en el Extranjero Becas Chile.

187 Microbial life in northern Chile: beyond multiresistance to heavy metals in a Poly-extreme environment

La vida microbiana en el norte de Chile: más allá de la multiresistencia a metales pesados en un ambiente poliextremo

Katherine Frez1, Saba Martínez1, Diego Cornejo 1, Daniela Meneses 2,1, Cristina Dorador 2,1. (1) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, CL (2) Centre for Biotechnology and Bioengineering, (CeBiB), Santiago, CL

El Altiplano del norte de Chile presenta distintas condiciones ambientales consideradas extremas, tales como temperaturas fluctuantes (-10ºC a 25ºC), aguas con alta salinidad y alta radiación UV (1000 W/m2). Sumando a esto, se destaca la presencia de altas concentraciones de metales pesados como arsénico (As), boro (B) y cesio (Cs) (4,0, 13,87, 2,0 mM respectivamente) en sistemas acuáticos. Se ha demostrado que en distintos ambientes del norte de Chile existe una alta diversidad microbiana capaz de desarrollarse en estas condiciones poliextremas, por lo que se propone que bacterias de estos ambientes presentarían multiresistencia a metales pesados. En este estudio se analizó la diversidad cultivable de bacterias de un sistema termal de altura (4500 msnm) llamado “Quebrada del Zoquete” cuyas aguas presentan temperaturas entre 12 y 80ºC. Las cepas obtenidas fueron cultivadas en medios CMD y MB a 20ºC, pH=7,0 en distintas concentraciones de As y Cu entre 0 a 150 y 1,2 a 1,7 mM respectivamente, con una concentración de 86 mM de sales totales. Para determinar su capacidad de oxidación o reducción se realizó un análisis colorimétrico empleando nitrato argéntico (AgNO3). Se han aislado 133 cepas, donde 7 de ellas (e.g. Streptomyces, Gemmobacter, Micromonospora) presentaron una resistencia >100 mM de As. Los aislados no toleraron concentraciones >1,7 mM de Cu, siendo inferior a lo reportado en literatura para el género Streptomyces con 7 mM de Cu, por consiguiente, Streptomyces no presentaría multiresistencia, resistiendo Arsénico, pero no Cobre. No se encontraron estudios de resistencia para Cu en Gemmobacter y Micromonospora.

FONDECYT N° 1181773 Dra.Cristina Dorador

188 Detection of harmful algae along the chilean coast using metabarcoding: potential applications to monitoring program

Deteccion de floraciones algales nocivas en las costas chilenas usando metabarcoding: potenciales aplicaciones al monitoreo

Gonzalo Fuenzalida1, Roland Sanchez2, Alejandro Montecinos3, Andrea Silva2, Pedro Calabrano1, Leonardo Guzmán1. (1) Centro Estudios de Algas Nocivas (CREAN), Instituto de Fomento Pesquero (2) Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias Universidad Austral De Chile, Universidad Austral de Chile (3) Universidad Austral de Chile (Sponsored by Instituto Fomento Pesquero)

Las floraciones algales nocivas (FANs) son un fenómeno recurrente en las costas chilenas, principalmente asociadas a especies productoras de toxinas como Alexandrium spp, Dinophysis spp y Pseudo-nitzschia spp, las cuales registran floraciones focalizadas principalmente entre las regiones X, XI y XII. Como medida de precaución para lasalud humana, cuando se registran incrementos significativos en las abundancias celulares de alguna de estos taxa (ej. A. catenella), las autoridades determinan el cierre de zonas de extracción de recursos marinos que potencialmente podrían acumular las toxinas producidas por estas especies. Durante el último tiempo floraciones de nuevas especies han sido reportadas y asociadas a mortalidades masivas de invertebrados, peces e incluso mamíferos marinos. En base a lo anterior surge la necesidad de desarrollar aproximaciones rápidas y precisas que permitan caracterizar la composición y abundancias de las especies que componen el fitoplancton en diferentes escalas espacio-temporales. En este sentido el metabarcoding ha sido una herramienta útil, la cual ha permitido revelar una gran biodiversidad de microrganismos presente en los océanos, así como factores bióticos y abióticos que la determinan. En este trabajo se describe las variaciones espacio-temporales durante el periodo de primavera verano (2018-2019) del ensamblaje fitoplanctonico en la Región de Los Lagos usando secuenciación masiva (Miseq) de segmentos ribosomales del gen 18S. Los resultados muestran la presencia de una alta diversidad de taxa, representadas mayoritariamente por los órdenes Thalassiosirales, Chaetocerotales, Gonyaulacales, Gymnodiniales, además se discute la aplicación de esta metodología como herramienta complementaria al monitoreo actual en FANs en la costa chilena.

PROGRAMA DE MANEJO Y MONITOREO DE LAS MAREAS ROJAS EN FIORDOS Y CANALES DE CHILE, XIII Etapa años 2019 - 2020.

CENTRO DE ESTUDIOS DE ALGAS NOCIVAS (CREAN) - INSTITUTO DE FOMENTO PESQUERO (IFOP)

189 Specific difference in bacterial composition between shower-head biofilm and shower water in Japanese bathroom

Diferencia específica en la composición bacteriana entre el biofilm de la ducha y el agua de la ducha en el baño japonés

So Fujiyoshi1,2, Fumito Maruyama2. (1) Graduate school of Human and Environmental Studies, Kyoto University (2) Scientific and Technological Bio-resource Nucleus, Universidad de La Frontera

Shower head in bathroom provides an excellent growth environment to microorganisms. However, little is known about the associated health risks, underlying processes of biofilm formation and microbiological quality in shower facilities. Many Japanese people prefer to take a bath for a long time everyday. Such a unique custom may make Japanese people being exposed to the inhabiting microorganisms. A purpose of this study is to clarify the possible infectious disease risk of Japanese shower, and to characterize bacterial communities to explain how the communities being composed. Here, we collected 34 water and biofilm samples in total from 18 different buildings across Japan. The V1-V9 variable regions of the 16S rRNA gene amplicon were sequenced using Oxford Nanopore MinION sequencer. The result showed only Methylobacterium and Sphingomonas were shared in all the biofilm samples. In contrast, the water community dominantly consisted of Methylobacterium and other 10 genera. The water communities contained significantly higher number of sequences identified as Ancylobacter, Alsobacter and other 38 genera than those in biofilms (P<=7.0e-4). The result suggests that the bacterial communities in water ware distinct from those in biofilms. The proportion of the number of shared bacteria found in both water and biofilm were about two times higher in the biofilm than those in water (P=0.0008 < 0.005). This may indicate that bacteria in water primarily adhered to shower head surface and form unique bacterial community. In addition, much lower percentage of pathogen in Japanese shower were distributed compared to those found in U.S. and Europe.

This work was supported by JST-JICA, SATREPS under JPMJSA1705 and AMED under Grant Number 18fk0108 to FM.

190 Effects of copper nanoparticles and pesticides on metabolic activityNitrobacter of winogradskyi

Efectos de nanopartículas y pesticidas sobre la actividad metabólica de Nitrobacter winogradskyi

Roberto Gajardo-Alister1, Gonzalo Tortella 2, Boris Parra1, Paulina Cifuentes1, Miguel Martinez1. (1) Departamento de Microbiología, Facultad de Ciencias Biológicas, Universidad de Concepción (2) Departamento de Ingeniería Quimica , Facultad de Ingeniería, Ciencia y Administración, Universidad de La Frontera (Sponsored by Fondecyt 1161713)

Durante el último siglo, el empleo de fertilizantes y pesticidas ha mejorado la producción agrícola, sin embargo, afectando la participación bacteriana en la nitrificación, causando una alteración del ciclo del nitrógeno. El objetivo de este estudio fue evaluar el efecto de nanopartículas de cobre y pesticidas sobre la actividad metabólica de Nitrobacter winogradskyi ATCC 25391. N. winogradskyi fue expuesta simultáneamente a nanopartículas de cobre metálico, nanopartículas de óxido de cobre, Cu2SO4, Iprodione, Carbendazim, 2,4-D, 3,5-dicloroanilina, catecol y 2,4-diclorofenol. Se evaluó la actividad metabólica mediante la reducción de sales de Tetrazolium (WST) y la actividad nitrificante mediante el ensayo de Griess.

Los resultados indicaron que las nanopartículas de cobre, Cu2SO4 y derivados químicos disminuyen la reducción de WST, sugiriendo una menor actividad metabólica. Al contrario, los pesticidas no afectaron dicha actividad, mientras que la actividad nitrificante disminuyó 90% luego de 30 días en los tratamientos con nanopartículas de cobre (II). Los resultados sugieren que las nanopartículas de cobre metálico generan una mayor disminución de la actividad metabólica deN. winogradskyi en comparación con pesticidas o sus derivados. Se sugiere que el uso de las nanopartículas de cobre en agricultura podría ser riesgoso para el ciclo biogeoquímico del nitrógeno.

Este proyecto ha sido financiado por proyectoFondecyt 1161713

191 Complete genome sequencing of a guaiacol-degrading Pseudomonas sp. and identification of genes encoding a novel o-demethylase system

Secuenciación completa del genoma de una pseudomonas sp. degradadora de guaiacol e identificación de genes que codifican un nuevo sistema de o-demetilasa

Sandra Janet Galaz1, Raúl Donoso1, Danilo Pérez-Pantoja1. (1) Biotecnología e Industria Alimentaria , Facultad de ciencias naturales, matemática y medio ambiente , Universidad Tecnológica Metropolitana

The volatile compound guaiacol (2-methoxyphenol) is one of the main low-molecular weight products generated after depolymerization of lignin. For this reason, guaiacol metabolization has been identified as a key targetto increase the efficiency of lignocellulose bioconversion. Guaiacol is toxic to most bacterial species, directly acting as an inhibitor of bioconversion processes based in lignocellulose. Nevertheless, its bacterial degradation has been described both in Gram positive and negative bacteria, proceeding through O-demethylation in one single step to generate catechol. In previous reports soluble cytochrome P450 monooxygenases have been identified as responsible for aerobic demethylation of guaiacol in several bacterial species. We isolated a Gram negative bacterium by its ability to use guaiacol as sole carbon and energy source from a pulp-mill wastewater plant. The bacterium was denoted as strain GL52 and identified as Pseudomonas sp. based in partial 16S sequencing. Genomic DNA was extracted from strain GL52 for sequencing by using an Illumina MiSeq platform. A draft assembly was generated by using de novo assembler SPADES and 70 contigs were obtained encompassing a ~4Mb genome. Comparative genomics of the strain GL52 with close related Pseudomonas strains but unable to degrade guaiacol, allows us to predict genes putatively responsible for o-demethylation. These genes are not related to a cytochrome P450 system, instead would be encoding a novel o-demethylase system belonging to the Rieske-type family of oxygenases. Gene expression analysis by qPCR was performed in order to confirm its role in guaiacol catabolism. These results expand the catabolic landscape in Pseudomonas genus.

ACKNOWLEDGMENTS: This study was supported by FONDECYT Grant N° 1161750 and CONICYT Research Ring N° ACT172128 from Chilean Government.

192 Rhizospheric actinomycetes isolated from organic crops of native potato Solanum tuberosum, L. and evaluation of their antagonistic activity against Phytophthora infestans (Mont) de Bary

Actinomicetos rizosféricos aislados de cultivos orgánicos de papa nativa Solanum tuberosum, L. y evaluación de su actividad antagonista a Phytophthora infestans (Mont) de Bary

Astrid Chumpitaz1, Nadia Galindo1, Junior Caro1, Sara Tupa1, Carolina Quispe1, Jeanne Alba1, Jorge León1. (1) Laboratorio de Ecología Microbiana, Ciencias Biológicas, Universidad Nacional Mayor de San Marcos

Introducción: La papa (Solanum tuberosum L.) es el cuarto cultivo de mayor consumo a nivel mundial. En Perú, más de 600 000 agricultores ven disminuir su producción debido a problemas fitosanitarios. El control de patógenos es a través de pesticidas, cuyo uso incontrolado agrava el problema en la cadena de producción y el deterioro ambiental. Objetivo: Determinar la capacidad antagonista de actinomicetos de la rizósfera de papa nativa frente al Oomiceto Phytophthora infestans, causante del “tizón tardío de la papa”. Materiales y métodos: Muestras de suelo rizosférico de papa fueron colectadas en el distrito de Cabana, provincia de Lucanas – Región Ayacucho. Los actinomicetos fueron aislados en Agar Avena y Agar Almidón Caseína luego de una incubación a 28°C por 7 días. Fueron caracterizados por pruebas convencionales de laboratorio; las pruebas de antagonismo se realizaron en agar Avena mediante la técnica de co-cultivo en placa, expresando los resultados en porcentajes de inhibición. Una cepa seccionada fue sometida a observación por Microscopía Electrónica de Barrido y su identificación molecular.Resultados: Se logró aislar 32 cepas de actinomicetos, siendo la mayoría productores de enzimas extracelulares como amilasa (100%) y celulasa (50%); crecen mejor a pH entre 7,5 - 8,5 y temperaturas de 25 – 30°C. Las pruebas de antagonismo mostraron que 71,9% de actinomicetos tienen actividad frente Phytophthoraa infestans, sobresaliendo la cepa CAB10-2, la cual logró alcanzar el 80,05% de inhibición al fitopatógeno.Conclusión: Ciertos actinomicetos rizosféricos de la papa son productores de compuestos bioactivos capaces de inhibir el desarrollo de Phytophthora infestans.

Vicerrectorado de Investigación y Posgrado (VRIP) – Universidad Nacional Mayor de San Marcos, Programa de Tesis de Pregrado (RR N° 06369-R-17)

193 Marine actinomycetes with antimicrobial activity against multidrug-resistant pathogens (MDR)

Actinomicetos marinos con actividad antimicrobiana a patógenos multidrogo-resistentes (MDR)

Nadia Regina Galindo1, Ulrike Tarazona1, Monica Huamán1, Emilio Marguet2, Marisol Vallejo2, Jorge León1. (1) Laboratorio de Ecología Microbiana, Ciencias Biológicas, Universidad Nacional Mayor de San Marcos (2) Cátedra de Biología Celular y Molecular, Ciencias Naturales , Universidad Nacional de la Patagonia San Juan Bosco, Trelew -Argentina

Introducción: Los actinomicetos marinos conforman un grupo de microorganismos ambientales con capacidad de producir novedosos compuestos bioactivos, cuyas estructuras y actividades farmacológicas difieren de sus contrapartes terrestres. Por otro lado, la presencia de patógenos multidrogo-resistentes es cada vez más frecuente, lo que motiva a la comunidad científica a la búsqueda de nuevas fuentes de metabolitos bioactivos como agentes terapéuticos alternativos.Objetivos : Aislar y seleccionar actinomicetos marinos con capacidad de producir metabolitos con actividad inhibitoria de patógenos multidrogo-resistentes. Materiales y métodos: Actinomicetos aislados de sedimento marino e invertebrados de las Bahías Independencia, Ancón y Paracas ((Perú) fueron caracterizados fenotípicamente y evaluados por su actividad inhibitoria de patógenos drogo-resistentes Gram positivos yGram negativos de origen clínico. Se determinaron la Concentración Mínima Inhibitoria (CMI) de extractos orgánicos de cepas seleccionadas, complementando con observaciones por Microscopía Electrónica de Barrido (SEM). Resultados: De un total de 26 (100%) actinomicetos, sólo 09 (34,6%) resultaron tener actividad antagonista a las cepas testigo drogo-resistentes; siendo I300 A, M10-77, M11-116A, M11-116D y M11-116d las de mayor actividad antagonista. Los patógenos más sensibles fueron Gram positivos (E. faecium Van A, E. faecium Van B, E. faecium 1724 y S. aureus ATCC 25923). Es destacable la CMI del extracto diclorometánico de M11-116D frente a E. faecium Van A y Van B (0,062 mg/ mL) y E. faecium 1724 (0,125 mg/mL). La SEM permitió observar numerosos filamentos hifales con esporas esféricas u ovoides. Conclusión:Los actinomicetos marinos tienen capacidad de producir metabolitos bioactivos que inhiben el desarrollo de patógenos multidrogo-resistentes.

Acuerdo Cooperación Científica – Tecnológica, MINCyT (Argentina) y CONCYTEC (Perú), 2014 - 2015.

194 UV-resistant bacteria from high-altitude Andean Lakes: genomic and ultrastructural studies

Bacterias de las Lagunas de Altura Puno Andina resistentes a UV: estudios genómicos y ultraestructurales

Fátima Silvina Galván1,2, Daniel Alonso1,2, Luciano Martinez2, Manuel Siñeriz2, María Eugenia Farías 1, Virginia Albarracin2. (1) Laboratorio de Investigaciones Microbiológicas de Lagunas Andinas (LIMLA)-PROIMI-CONICET (2) Centro de Investigaciones y Servicios de Microscopia Electrónica-CONICET-UNT

The HAALs are situated in northwest Argentina, Chile, and Bolivia at higher altitudes than 3,000 m. Their microbial communities have developed mechanisms for adaptations to extreme environmental factors, specifically UV. They constituted interesting models to carry out studies of compounds and systems involved in such adaptation, with promising biotechnological applications. In this work, we analyzed the genome and ultrastructure of twopoly- extremophilic bacteria upon UV-exposure: Exiguobacterium sp. S17 isolated from modern stromatolites from Laguna Socompa (3,750 masl) and Acinetobacter sp. Ver3 isolated from the Laguna Verde (4,100 masl). Cell cultures of S17 and Ver3 were subjected to artificial UV-B radiation for different times: 0 (control), 60, 90 and 120 min, taking aliquots at each time for SEM and TEM. Genome annotation of both strains were performed using the standard operating procedures (SOPs) for prokaryotic annotation from ISGA and from the RAST annotation server. BLAST was used to compare the genome with nearby species. The results showed that UV-B exposure tends to favor a greater degree of bacterial aggregation and intercellular communications, probably as a protection mechanism against radiation stress. Genomic survey indicated in both strains the presence of coding genes for intercellular pili type IV. In Ver3 are present the genes pilE, pilV, pilX, pilQ and the pilC, pilT, PilB, where the latter were also found in S17, and are responsible the assembly and the formation of aggregates and adhesion to surfaces. In future research, the aims are to examine the proteome and transcriptome of systems that involve intercellular communication.

PIUNT y CONICET

195 Ribosome profiling, an approach to study symbiotic interactions between beta-rhizobia and their host legumes

Ribosome profiling, una aproximación para el estudio de la interacción simbiótica entre beta- rizobios y sus leguminosas hospederas

Florencia Garabato1, Guillermo Eastman2, Laura Sandes1, Cecilia Rodriguez1, José Sotelo2, Raúl Platero1. (1) Bioquímica y Genómica Microbianas, Instituto de Investigaciones Biológicas Clemente Estable (2) Departamento de Genómica, Instituto de Investigaciones Biológicas Clemente Estable

El establecimiento de la simbiosis entre rizobios y sus leguminosas hospederas exige una expresión génica coordinada entre ambos organismos. Actualmente la información que tenemos sobre este dialogo molecular se basa en el estudio de las asociaciones entre los alfa-rizobios y sus hospederos, mientras que se tiene muy poca información sobre lo que ocurre en beta-rizobios. Por este motivo nuestro objetivo es estudiar las bases moleculares de la interacción entre el par simbiótico compuesto por el beta-rizobio Cupriavidus sp. UYMMa02A y Mimosa pudica.

Para esto proponemos la técnica de Ribosome profilling.Esta consiste en extraer los polisomas activos de las células y purificar los fragmentos de ARNm contenidos para su posterior secuenciación masiva y análisis bioinformatico. Estos fragmentos son llamados huellas ribosomales pues denotan la posición en la que se encontraba un ribosoma. De esta forma podemos estudiar el conjunto de ARNm que estén siendo traducidos activamente en la condición estudiada.

Hemos logrado poner a punto un protocolo para obtener las huellas ribosomales de la cepa en estudio crecida en medio líquido, consiguiendo cantidades suficientes para su secuenciación masiva. En el momento estamos aplicando el protocolo generado para estudiar la huellas ribosomales de la cepa en presencia del flavonoide inductor luteolina, mientras que en paralelo realizaremos un RNA-seq de la misma condición con el objetivo de evaluar simultáneamente cambios en traducción y transcripción. La integración de estos datos, nos permitirá elaborar un modelo que indique las principales señales y vías metabólicas implicadas en las primeras etapas del establecimiento de la simbiosis.

196 Functional metagenomics of consortia enriched in synthetic mixtures of lignocellullose-derived inhibitors for selection of tolerance-conferring genes

Metagenómica funcional de consorcios enriquecidos en mezclas sintéticas de inhibidores derivados de lignocelulosa para selección de genes que confieren tolerancia

Carla Gárate-Castro1, Raúl Donoso1, Marcelo Araya-Nail1, Mauricio Guajardo-Parra2,1, Danilo Pérez-Pantoja1. (1) Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación (PIDi), Universidad Tecnológica Metropolitana (2) Universidad Tecnológica de Chile Inacap

The great increase in the worlds energy demand has led to the search for renewable sources not relying in fossil fuels. The bioethanol obtained from renewable substrates such as lignocellullose is an affordable and sustainable alternative. The lignocellullose is composed of lignin (aromatic heteropolymer), cellullose and hemicellullose (carbohydrate polymers) and it can be abundantly obtained from agricultural wastes. During hydrolysis of lignocellulosic biomass for bioethanol production several syde-products are generated, including furans such as furfural and 5-hydroxymethylfurfural (HMF); and phenolics such as 4-hydroxybenzaldehyde (4HB), guaiacol, vanillin, syringic acid and syringaldehyde among others. They are collectively named lignocellullose-derived inhibitors (LDIs) because are highly toxic and their presence in the bioethanol fermentation severely decrease process yield. The molecular effects of LDIs include disruption of membrane integrity, dissipation of ionic gradients, ROS generation, inhibition of glycolytic and fermentative enzymes and DNA damage, among others.

One way to solve the LDIs toxicity is to improve tolerance in fermentative microorganisms such asE. coli, by introducing tolerance genes. An attractive source of tolerance genes includes microbial communities adapted to grow in the presence of LDIs. In this work, we have constructed metagenomic libraries of microbial consortia enriched in complex mixtures of LDIs to carry out functional selection in 6 different inhibitors including furans and aromatic aldehydes. In total, 6 different clones were identified by tolerance to LDIs including Fufural/HMF, guaiacol, vanillin, 4HB and syringaldehyde. The functional analysis revealed that multiple molecular functions can be recruited in LDIs tolerance. FONDECYT Grant N° 1161750 and CONICYT Research Ring N° ACT172128 from Chilean Goverment.

197 Changes in the microbial communities of the soil of the Atacama Desert due to the presence of extraterrestrial rock

Cambios en la comunidad microbiana de suelos de el Desierto de Atacama debido a la presencia de Rocas Extraterrestres

Jonathan García Araya6,2,1, Vladimir Avalos2, Millarca Valenzuela4,3, Cristina Dorador5,2,6. (1) Facultad de Ciencias de la Salud, Doctorado en Ciencias Biológicas, Universidad de Antofagasta (2) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta (3) Departamento de Ciencias Geológicas, Universidad Católica del Norte (4) Instituto Milenio de Astrofísica (5) Departamento de Biotecnología, Facultad de Recursos del Mar y Recursos Biológicos, Universidad de Antofagasta (6) Centro de Bioingeniería y Biotecnología CeBiB

El Desierto de Atacama posee diferentes nichos ecológicos y además es una zona de acumulación natural de meteoritos debido a que no presenta alteraciones significativas en los últimos cientos de años. Los meteoritos poseen composición química diferente al resto de las rocas terrestres, por lo que es interesante saber si la presencia de estos estarían modulando la estructura microbiana de los suelos. Se realizó una recolección al sector de Los Vientos, cercano al Very Large Telescope Observatorio Astronómico Cerro Paranal, Chile. Seleccionando 3 meteoritos con zona de estudio de 2 m2, muestras en superficie (0-5 cm) y en profundidad (5-10 cm) fueron tomadas y se incluyo una zona control (no meteorito). En total, 136 muestras fueron estudiadas. El suelo fue analizado químicamente y las muestras se sometieron a secuenciación del 16S ARNr por Illumina Miseq (regiones hipervariables V3-V4). La clasificación taxonómica fue realizada con el software Qiime v1.9.1 y la base de datos SILVA 128. Lacomunidad microbiana fue dominada por los Phyla: Actinobacteria, Proteobacteria, Chloroflexi y Bacteroidetes. A nivel de Familia fue detectado que una gran parte de la abundancia fue representado por microorganismos no cultivables con un 42.5% del total de abundancia relativa, Chitinophagaceae (2.8%) y grupo DA101 (2.4%). Los resultados preliminares indican una importante diferencia entre las comunidades microbianas de superficie v/s profundidad, además, existe una modificación en la estructura de la comunidad microbiana cerca del meteorito, lo que sugiere un efecto directo debido a la presencia de esta roca extraterrestre por sobre las comunidades microbianas terrestres.

Red NEXER – CeBiB, PIA-CONICYT FB0001 - Fondecyt 1140179-1181773 and CONICYT scholarship for Doctoral studies

198 Importance of immigration in activated sludge system revealed by patterns of occurrence and bacterial abundance

Importancia de la inmigración en un sistema de lodos activados revelada por patrones de ocurrencia y abundancia bacteriana

Maria Carolina Garcia1, Hu Anyi 2, Oladier Hoyos2, Diego Fernando Ramirez2, Juan Pablo Niño Garcia2. (1) Escuela de Microbiologia, Universidad de Antioquia (2) Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences

La inmigración de bacterias del agua residual es uno de los procesos que modulan el ensamblaje de las comunidades de los sistemas de lodos activados. Se sabe que a través de este mecanismo pueden ingresar bacterias con la capacidad de crecer y mantener así su abundancia en el reactor o que pueden permanecen abundantes en el sistema a pesar de estar inactivas, debido a sus altas densidades en el afluente. Sin embargo, se desconoce cuál es la proporción de estos dos tipos de bacterias inmigrantes y cómo varía esta proporción en el tiempo. Por lo tanto, aquí se analizan los cambios en la ocurrencia y abundancia de aquellos componentes de las comunidades bacterianas que están presentes tanto en el afluente como en el tanque de aireación, a lo largo de un ciclo anual en un sistema de lodos activados de la ciudad de Medellín, Colombia. Para esto, realizamos el seguimiento de las comunidades bacterianas del afluente y del tanque de aireación, utilizando ILLUMINA Hi-Seq de las regiones variables del gen ribosomal 16S. Al analizar las ocurrencias de los cerca de 5000 OTUs, encontramos que hay una alta proporción de OTUs compartidos entre el afluente y del tanque de aireación. Un resultado interesante es que estos OTUs compartidos representan una proporción importante de la abundancia total de la comunidad de dicho tanque, lo que sugiere que estos microorganismos pueden colonizar efectivamente este sistema. Sin embargo, su importancia cuantitativa cambia a lo largo del año, en relación con los cambios hidrológicos estacionales

199 Arctic on a flask: phytoplankton culturable diversity

Ártico en un matraz: diversidad cultivable de fitoplancton

Catherine Gérikas Ribeiro1,3, Adriana Lopes Dos Santos2,3, Priscillia Gourvil1, Florence Le Gall1, Dominique Marie1, Ian Probert1, Margot Tragin1, Daniel Vaulot1,2. (1) Sorbonne Universités, UPMC Université Paris 06, CNRS, UMR7144, Station Biologique de Roscoff, Roscoff, France. (2) Nanyang Technological University, Asian School of the Environment, Singapore (3) Universidad Mayor, Centro GEMA - Genómica, Ecología y Medio Ambiente, Chile. Key words: Arctic diatoms; Arctic flagellates; isolation techniques; 18S rRNA; Roscoff Culture Collection

The increasingly thinner pack ice and the formation of melt-ponds allow viable areas for bloom development in almost one third of the ice-covered Arctic Ocean in the summer. An extensive culturing effort was conducted before and during a phytoplankton bloom in Baffin Bay between April and July 2016. Different isolation strategies were applied, including flow cytometry cell sorting, manual single cell pipetting and serial dilution. Although allthree techniques yielded the most common organisms, each technique retrieved specific taxa, highlighting the importance of using several methods to maximize the number and diversity of isolated strains. More than 1,000 cultures were obtained, characterized by 18S rRNA sequencing and optical microscopy and de-replicated to a subset of 276 strains. Strains grouped into 57 genotypes defined by 100% 18S rRNA sequence similarity. These genotypes spread across five divisions: Heterokontophyta, Chlorophyta, Cryptophyta, Haptophyta and Dinophyta. Diatoms were the most abundant group (193 strains), mostly represented by the genera Chaetoceros and Attheya. The genera Rhodomonas and Pyramimonas were the most abundant non-diatom nanoplankton strains, while Micromonas polaris dominated the picoplankton. Diversity at the class level was higher during the peak of the bloom. Potentially new species were isolated, in particular within the generaNavicula , Nitzschia, Coscinodiscus, Thalassiosira, Pyramimonas, Mantoniella and Isochrysis. It is important that culturing efforts continue in the Arctic, as ongoing and predicted loss in ice coverage and thickness will certainly impact plankton diversity, dynamics and community structure.

200 Genomic and physiologic characterization of new mixotrophic arsenic oxidizingAncylobacter isolated from high Andean sediments near Tacora volcano

Caracterización genómica y fisiológica de un nuevo Ancylobacter mixotrófico y oxidante de arsénico aislado de sedimentos del alto Andes cerca del volcán Tacora

Rosa Godoy-Morán1, Ana Moya-Beltran2,3,4, Michael Schlömann5, Ignacio T. Vargas1, Quatrini Raquel2, Mario Vera1,6. (1) Departamento de Ingeniería Hidráulica y Ambiental, Facultad de Ingeniería, Pontificia Universidad Católica de Chile (2) Microbial Ecophysiology Laboratory, Fundación Ciencia y Vida (3) Facultad de Ciencias Biológicas, Universidad Andrés Bello (4) Millennium Nucleus in the Biology of the Intestinal Microbiota (5) Institut für Biowissenschaften, Technische Universitaet Bergakademie (6) Instituto de Ingeniería Biológica y Médica, Pontificia Universidad Católica de Chile

Arsenic is an extremely toxic metalloid that causes adverse effects on human health and the environment. Its remediation requires chemical or biological oxidation of arsenite to arsenate, followed by physical removal. Much interest exists in microorganisms displaying arsenite oxidation capacities to develop cost-effective remediation biotechnologies. To date, only a handful of aerobic chemolithoautotrophic arsenite-oxidizing (CAO) bacteria have been described. Tacora, a volcano of Chilean Andes, harbors large sulfur deposits containing arsenic and other toxic elements. An arsenite-oxidizing strain (designated TS-1), with promising CAO activity, was isolated from sediments near Tacora. Here, we report the closed genome sequence (3.96 Mb) and annotation of TS-1, together with the metabolic reconstruction of its As-related capacities. The genome was assembled from PacBio and Illumina sequence information, using a hybrid method. Taxonomic assignment was done based on 16S rRNA gene phylogenetic analysis and OGRIs comparison. TS-1 shares with its closest sequenced relative (Ancylobacter rudongensis) an ANI of 83% and a dDDH of 26.6%. According to 16S rRNA gene phylogeny, it branches apart from acknowledged species. These results indicate that TS-1 is a new specie of the Ancylobacter genus. TS-1’s growth on arsenite (1mM), as only electron donor, was demonstrated. In addition, TS-1 can grow with glucose as electron donor. Genes and gene clusters for arsenite oxidation were identified and mapped to mobile genetic elements, highlighting the role of horizontal gene transfer in adaptation to arsenic-rich environments. These results outline the potential role of mixotrophic arsenite-oxidizing microorganisms in natural environments and allow to propose arsenite-oxidizing biotechnologies.

FONDECYT 1161007 (MV) FONDECYT 1160917 (IV) CONICYT-PFCHA/Doctorado Nacional/21171049 (AMB) FONDECYT 1181251 (RQ) Basal AFB170004 (RQ)

Millennium Science Initiative, Ministry of Economy, Development and Tourism of Chile under Grant “Millennium Nucleus in the Biology of the Intestinal Microbiota”

201 UbiquityMicrobiome: A new R programming package for the simultaneous visualization of ubiquity and relative abundance of microbial taxa

UbiquityMicrobiome: un paquete de R para la visualización simultánea de ubicuidad y abundancia relativa de comunidades microbianas

Gilmary Ortiz-Morales1, Filipa Godoy-Vitorino2. (1) Department of Natural Science, Interamerican University of Puerto Rico (2) Microbiome Lab, Department of Microbiology and Medical Zoology, University of Puerto Rico, School of Medicine (Sponsored by Filipa Godoy-Vitorino)

Analyses of microbiota survey datasets, typically result in OTU table formats, that are used in downstream alpha and beta diversity analyses, for the study community structure and dynamics in microbe-host associations. Here we propose the availability of an integrative visualization tool to offer new insights into community structure and ubiquity across samples, as well as to provide a practical analytical tool for simultaneous inter-kingdom or multi metadata. The program uses basic arithmetical functions that work concurrently with OTU table counts and the metadata file. Relative abundances are calculated as well as the proportion of samples associated with each taxon’s relative abundance (ubiquity). The abundance and proportion attributed to each taxon’ ID and domain are then assigned to the user metadata category. The resulting data frame is “melted” into one frame containing all the calculated elements for data visualization. Our UbiquityMicrobiome package is a new visualization tool to appreciate OTU ubiquity, relative abundance, and dominance in microbiome samples.

202 Definition of functional groups in marine bacterioplancton and their relationship with bacterial biomass production

Definición de grupos funcionales en el bacterioplancton marino y su relación con la producción de biomasa bacteriana

María Belén González1, John Garzón2, Rubén Lara2, Gonzalo Greif3, Emiliano Pereira4, Cecilia Alonso1. (1) Ecología Funcional de sistemas acuáticos , Centro Universitario de la Región Este, Universidad de la República (2) Instituto Argentino de Oceanografía, Bahía Blanca, Argentina. (3) Unidad de Biología Molecular, Istitut Pasteur de Montevideo (4) Instituto Max Planck para Microbiología Marina. Bremen, Alemania

En tiempos de auge de la evaluación exhaustiva de la diversidad microbiana y la búsqueda de patrones que vinculen dicha diversidad con funciones medibles a escala ecosistémica, es imprescindible aplicar aproximaciones que permitan organizar (y reducir) dicha diversidad a grupos funcionales. En este trabajo se definieron grupos funcionales en base a detectar asociaciones significativas de OTUs, utilizando partición por k-means y concordancia de los grupos empleando el coeficiente de Kendall. Para ello se trabajó con 51 muestras de agua superficial colectada endos muestreos de primavera (2016- 2017), en un gradiente marino desde zona costera hasta talud en el Atlántico Sur. Allí se midieron una serie de variables fisicoquímicas, incluyendo propiedades espectrales de la materia orgánica disuelta (MOD), a la vez que se estimaron las tasas de producción de biomasa bacteriana (PB). A continuación, se emplearon Modelos Lineales Generalizados y Random Forest para analizar la dependencia de la PB en relación a las diferentes variables fisicoquímicas y grupos funcionales definidos. Las variables fisicoquímicas más significativas en determinar las tasas de PB fueron oxígeno, origen y peso molecular de la MOD, en tanto que varios de los grupos funcionales bacterianos fueron retenidos en el mejor modelo, encontrándose dos de ellos entre las variables con mayor significancia. Estos resultados además de demostrar el potencial de estas herramientas de análisis, aportan una nueva mirada a la función PB, para la cual se han analizado ampliamente los condicionamientos ambientales, pero escasamente el rol de grupos bacterianos específicos.

Proyecto binacional (Uruguay-Argentina) ANII-CONICET.

203 Production and characterization of keratinolytic enzymes byStreptomyces sp. CHA1, isolated from marine sediments of the Chilean coast

Producción y caracterización de enzimas queratinolíticas sintetizadas por Streptomyces sp. CHA1, aislada de sedimentos marinos de costas chilenas

Valentina Alejandra González1, Pedro Valencia2, Beatriz Cámara1. (1) Departamento de Química, & Centro de Biotecnología D. Alkalay L. , Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Universidad Técnica Federico Santa María (2) Departamento de Ingeniería Química y Ambiental, Universidad Técnica Federico Santa María

Feathers are produced in large amounts as a waste by-product of poultry processing plants. A current value-added use for feathers is the conversion to feather meal for animal feed, using physical and chemical treatments. These methods can destroy certain amino acids and decrease protein quality and digestibility. As an alternative, keratinolytic microorganisms and their enzymes may be used to enhance the digestibility of feather keratin. Microbial keratinases can be obtained from both fungi and bacteria, where, among the latter, Actinobacteria have been recognized as important keratinase-producers. Actinobacteria are one of the most diverse groups, are present in various ecological habitats including marine environments. The enormous diversity of environmental pressures in the marine ecosystem provide a potential natural reservoir for the discovery of new enzymes. Previously, based on a screening for keratinolytic activity,Streptomyces sp. CHA1, isolated from marine sediments from Chañaral de Aceituno, showed the highest level of keratinolytic activity and was selected for further characterization. The production of keratinolytic enzyme of this strain was characterized by varying physical culture conditions such as temperature (15°C-37°C), inoculum percentage (2.5- 10% v/v), and feather concentration (5-20%). A partial characterization of its crude enzymatic extracts was carried out. Maximum keratinolytic activity was observed at 60°C. Interestingly, keratinolytic profiles (at constant temperature) presented two maximum activities, one at pH 4 and a second at pH 9. Also, at least four protein bands showed enzymatic activity in zymogram. In the present work, we report marine keratin-degrading Streptomyces, which has high potential to degrade keratin-rich waste.

Beca Doctorado Nacional CONICYT N° 21161188, Fondecyt Regular N° 1171555, Conicyt PIA ACT172128

204 Microbial communities as indicators of environmental status: preliminary study in two coastal lagoons applied to emerging pollutants

Comunidades microbianas como indicadoras de calidad ambiental: estudio preliminar en dos lagunas costeras aplicado a contaminantes emergentes

Luciana Griffero1, Belén Gonzáles1, Jaime Alcántara-Durán2, Juan Francisco García-Reyes2, Gonzalo Greif3, Emiliano Pereira4, Andrés Pérez-Parada5, Cecilia Alonso1. (1) Grupo Ecología Microbiana de Sistemas Acuáticos, Centro Universitario Regional Este, Universidad de La República (2) Departamento de Química Física y Analítica, Universidad de Jaén (3) Institut Pasteur de Montevideo (4) Instituto Max Planck para Microbiología Marina (5) Departamento de Desarrollo Tecnológico, Centro Universitario Regional Este, Universidad de La República

La ocurrencia de contaminantes emergentes (CEs) en los ecosistemas acuáticos modifica la estructura y actividad de sus comunidades biológicas. Entre éstas, la comunidad microbiana es clave en procesos que determinan la calidad ambiental, tales como la degradación de contaminantes orgánicos. Por otra parte, los microorganismos son capaces de reflejar rápidamente los cambios en su hábitat, por lo que recientemente se ha postulado su consideración como indicadores de calidad ambiental. En este trabajo, se analizaron variables fisicoquímicas (incluyendo CEs) y comunidades bacterianas en las cuencas de dos lagunas costeras ubicadas en la costa Atlántica uruguaya, en 22 puntos muestreados estacionalmente a lo largo de un año. A través de la secuenciación masiva de una región hiper- variable del gen codificante para ARNr 16S, se determinaron OTUs (Unidades Taxonómicas Operacionales) que fueron sometidas al análisis de su valor indicador (IndVal). Dicho análisis permitió identificar OTUs o combinaciones de éstas, pasibles de ser usadas como indicadoras de grupos de muestras de arroyos, lagunas y mar costero, definidos en base a la presencia de CEs. Se encontraron indicadores compuestos por especies pertenecientes a diferentes filos bacterianos, que respondieron de manera significativa y diferencial al tipo y concentración de CEs. La capacidad para predecir las muestras pertenecientes a los diferentes grupos utilizando estos indicadores fue alta. Los valores de IndVal obtenidos fueron relativamente altos en comparación con otras comunidades típicamente utilizadas como bioindicadores, confirmando a las comunidades bacterianas como candidatos prometedores para el desarrollo de estrategias de monitoreo y conservación de los sistemas acuáticos.

205 Isolation, Identification and Characterization of Acidophilic Iron-oxidizing Psychrotolerant Bacteria, From Polar and Subpolar Environments

Aislamiento, identificación y Caracterización de Bacterias Acidófilas Psicrotolerantes Hierro Oxidantes a partir de Ambientes Polares y Subpolares”

Jonnathan Grossolli Gálvez1, Claudia Muñoz-Villagrán1, Ximena Valenzuela2, Alonso Ferrer3, Beatriz Díez4, Gloria Levicán1. (1) Laboratorio de Microbiología Básica y Aplicada, Facultad de Química y Biología, Universidad de Santiago de Chile (2) Programa de Biorremediación, Campus Patagonia, Universidad Austral de Chile (3) Núcleo de Química y Bioquímica. Facultad de Estudios Interdisciplinarios, Universidad Mayor, Santiago, Chile (4) Laboratorio de Ecología Microbiana y Microbiología Ambiental, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile

Bioleaching processes are carried out by aerobic, acidophilic, iron-oxidizing and, mainly, mesophilic Bacteria and Archaea. However, most mining sites are located in areas where the mean temperature is lower than the optimal growth-temperature of these microorganisms. Therefore, the isolation of psychrophiles or psychrotolerant iron- oxidizing strains is an increasing necessity in the industry. In order to isolate this kind of microorganisms, sites located in environments with low temperature, acidic pH and high concentration of dissolved metals were selected. Sites included an abandoned mine site in Puerto Guadal in Patagonia area (Aysén, Chile) and an acid mine drainage (AMD) in Marian Cove (King George Island, Antarctic) where the temperature can be 0ºC or less. Solid samples were cultured in three variants of 9K (pH 1.6), and 882 culture media (pH 1.8), and were incubated at 20°C until achieving iron- oxidation. Cell cultures with the fastest iron-oxidation rate were characterized and identified by sequencing of 16S RNA gene. The samples PC05 from Puerto Guadal and MC02 from Marian Cove presented significant iron-oxidation at 48 h and were identified as belonging to the bacterial species Acidithiobacillus ferrivorans. The isolates strains were able to grow from 5°C to 30°C, being 20°C the optimal growth-temperature, and showed a rod-shape by TEM and SEM analyses. The finding of these strains open novel perspectives to satisfy the current challenges of the ore bioleaching industry.

This work was funded by INACH RT_31-16 Grant from government of Chile, Dicyt-USACH, and Basal project USA1799/1555/1498 from USACH. FIC-Región de Aysén 2017 BIP40000480.

206 Construction of a plurigenomic library that includes microorganisms highly tolerant to inhibitors of microbial growth derived from lignocellulose and functional selection of genes that confer tolerance to inhibitors in E. coli

Construcción de una genoteca plurigenómica que incluye microorganismos altamente tolerantes a inhibidores de crecimiento microbiano derivados de la lignocelulosa y selección funcional de genes que confieren tolerancia a los inhibidores en E. coli

Mauricio Guajardo-Parra1,2, Marcelo Araya-Nail1, Carla Gárate-Castro1, Danilo Pérez-Pantoja1. (1) Programa Institucional de Fomento a la I+D+i, Universidad Tecnológica Metropolitana. Santiago, Chile. (2) Universidad Tecnológica de Chile Inacap

The lignocellulosic biomass is a renewable alternative in the search for energy sources that would replace fossil fuels. Lignocellulose is mainly composed by cellulose and hemicellulose, both constituted by long polysaccharides; and lignin, which is formed by polymers of aromatic compounds. For biofuel production a pretreatment step capable of release sugars to be assimilated by microorganisms is necessary. However, during this step lignocellulose-derived inhibitors (LDIs) are generated that decreased the biofuel yield. The main LDIs include furan aldehydes such as furfural and 5-hydroxymethylfurfural; or phenolics such as syringaldehyde, 4-hydroxybenzaldehyde and vanillate among others. Our hypothesis is that the construction of plurigenomic libraries using microorganisms from harsh environments, will allow finding complementary genes toE. coli that can counteract the toxicity of these compounds. We explored microbial environments impossing chemical stress such activated sludge involved in pulp-mill effluents depuration or disposal lagoons of olive mill wastewater. Several strains highly tolerant to furfural, vanillate and syringaldehyde were isolated. They were identified as belonging to Microbacterium, Pseudomonas, Enterobacter and Achromobacter genera, among others. The isolates were able to grow at concentrations much higher than those reported for laboratory strains. The construction of a plurigenomic library in E. coli was carried out using isolates showing higher tolerance levels, followed by functional screening for six differents LDIs. At least eight independent clones were selected by conferring tolerance to at least one LDI. The genes identified by sequencing revealed a broad diversity of cellular functions including membrane transport proteins, transcriptional regulators, and metabolic enzymes among others.

This study was supported by FONDECYT Grant N° 1161750 and CONICYT Research Ring N° ACT172128 from Chilean Government.

207 Viral communities of thermophilic phototrophic mat: characterization and ecological function

Comunidades virales the tapetes fototróficos termales caracterización y rol ecológico

Sergio Guajardo-Leiva1, Oscar Salgado1, Beatriz Díez2,1. (1) Genética Molecular y Microbiología, Biología, Pontificia Universidad Católica De Chile (2) Centro de Ciencia del Clima y la Resiliencia (CR)2

Viruses are ubiquitous in all environments and hot-springs are not the exception even though its extreme conditions. Phototrophic mats of terrestrial hot-springs have been used for decades as models for understanding the composition, structure, and function of microbial communities in nature. Therefore, they provide a theoretical framework in which to study the viral component of these communities. Here, our main aim was to characterize the structure, activity, lifestyle, and putative host of the thermophilic viral communities and compare them at a local and global scale. In particular, we studied the lytic and lysogenic viral communities of phototrophic microbial mats in two Chilean Patagonia hot-springs (Porcelana and Cahuelmó).

Our results showed that these viral communities are dominated by Caudovirales order being cyanophages the most active group. The viral communities are also genetically diverse, and structured in a classic log-normal distribution, dominated by approximately 21 genotypes out of more than 800 detected. Our evidence, suggest that viruses exert an impact on their hosts by lytic-interactions that stimulate the coevolution of the most active and abundant host- virus pairs such as the cyanobacteria (genus Fischerella) and cyanophages (Podoviridae family). On the other hand, lysogenic-interactions influence the fitness of heterotrophic hosts such as Proteobacteria and Firmicutes, through lysogenic conversion. Lastly, we propose that hot-spring viruses followed a biogeographic pattern in which the viruses are passively transported by air on a local and global scale, but then locally structured influenced by environmental conditions (pH and temperature) that primarily affect the structure of the host community.

Beca de doctorado nacional CONICYT N° 21130667; FONDECYT N° 1150171 y N° 1181656; FONDAP 15110009

208 Impact of p-cresol intestinal metabolism on the neural morphology, electrophysical parameters and gut-microbiome

Impacto del metabolito intestinal p-cresol sobre la morfologia neuronal, parámetros electrofisiológicos y microbiota intestinal

Sheyla Guzmán1, Cristina Dorador2, Waldo Cerpa3, Pedro Zamorano1. (1) Laboratorio de Neurobiología, Ciencias de la Salud, Universidad de Antofagasta (2) Instituto Antofagasta y Biotecnología, Facultad del Ciencias del Mar , Universidad de Antofagasta (3) Biología Celular y Molecular, Ciencias Biológicas, Pontificia Universidad Católica de Chile

El trastorno del espectro autista (TEA) afecta 1 cada 59 niños. Recientemente, se ha vinculado la microbiota intestinal alterada con aumento en especies Clostridium con TEA. Clostridium producen p-cresol como producto del metabolismo de tirosina. Estudios correlacionan niveles urinarios elevados de p-cresol en niños TEA. El desarrollo dendrítico en TEA es anormal, el cual se refleja en alteraciones conductuales y función sináptica, además de presentar microbiota intestinal alterada. Este estudio analiza el efecto de p-cresol en el desarrollo morfo-dendrítico y densidad sináptica en cultivos de neuronas hipocampales, parámetros electrofisiológicos en cortes de hipocampo, comportamiento social y la microbiota intestinal. El efecto de p-cresol en la función sináptica, se evaluó mediante fEPSP (entrada/ salida) y facilitación por pulsos pareados, en ratas tratadas con 30 mg/kg de p-cresol durante 12 días. Además, se evaluó comportamiento social de ratas con la prueba de las tres cámaras. Las muestras fecales se sometieron a secuenciación masiva del gen ribosomal 16S (Ilumina) para determinar las comunidades microbianas. Nuestros resultados mostraron que 50mM de p-cresol tiene efecto significativo en el desarrollo morfo-dendrítico de neuronas hipocampales a 7DIV y 15DIV, disminuyendo ramificaciones dendríticas y densidad sináptica.Además, el tratamiento con p-cresol mostró una alteración en la maquinaria presináptica debido a una disminución en facilitación sináptica. Preliminarmente, p-cresol promueve la reducción de la relación Bacteroidetes/Firmicutes después del tratamiento. Los resultados muestran que p-cresol modula el desarrollo morfo-dendrítico y la función sináptica. Este hallazgo sugiere que p-cresol podría contribuir en las alteraciones que se presentan el sistema nervioso central en individuos TEA.

CeBiB FB0001; Fondecyt 1140179, 11817

209 The High and Low microbial abundance dichotomy in marine sponges from the north coast of São Paulo (Brazil)

La dicotomía de la alta y baja abundancia microbiana en esponjas marinas de la costa norte de San Pablo (Brasil)

Cristiane C. P. Hardoim1, Andressa C.M. Ramaglia1, Virginia Carrara1, Gisele Lobo-Hajdu2, Márcio Reis Custódio3. (1) não aplica-se, Universidade Estadual Paulista (2) Departamento de Genética, Universidade do Estado do Rio de Janeiro, Rio de Janeiro (3) Departamento de Fisiologia Geral (IB) e Centro de Biologia Marinha (CEBIMar), Universidade de São Paulo

Marine sponges harbor diverse microbial communities in which complex interactions are established. Based on the microbial abundance, the species have been classified in high microbial abundance (HMA) and low microbial abundance (LMA) sponges. Even though dozens of sponge species have being classified worldwide as HMA or LMA, there is none sponge from Brazilian coast. To address this, the sponge species Aplysina fulva, A. caissara (endemic), Tedania ignis, Ptilocaulis walpersi, Dragmacidon reticulatum, Halichondria cebimarensis (endemic) and Mycale angulosa were collected at Praia do Segredo, Praia Preta, Prainha and Ponta do Recife, in the north coast of São Paulo State (Brazil). The sponge species were identified using morphological characteristics and by barcoding using the genes cytochrome oxidase subunit 1 (cox-1) and cytochrome b (cob). The DNA was subjected to Illumina MiSeq platform using the phylogenetic marker 16S rRNA. The cob was capable to separate A. fulva, A. caissara, T. ignis, P. walpersi and D. reticulatum into distinct clusters, whereas cox-1 was able to distinguish H. cebimarensis (endemic) and M. angulosa. Preliminary results from the Illumina sequences showed that the highest alpha diversity metrics were detected in A. fulva, A. caissara and D. reticulatum than in P. walpersi, M. angulosa, H. cebimarensis and T. ignis. Several phyla, classes, and OTUs were found differentially abundant in either group. Additionally, HMA and LMA indicators were also detected. These results demonstrated for the first time that A. fulva, A. caissara and D. reticulatum are HMA, whereas P. walpersi, M. angulosa and H. cebimarensis are LMA. São Paulo Research Foundation (FAPESP, nr. 2016/17189-7)

210 Distribution, genomic potential and metatranscriptomic activity of Alteromonas in low oxygen waters of the South Pacific Ocean

Distribución, potencial genómico y actividad trancriptómica de Alteromonas en aguas deficientes de oxígeno del Océano Pacífico Sur

Carlos Henríquez-Castillo2,1, Salvador Ramírez-Flandes1, Anthony Bertagnolly3, Frank Stewart3, Osvaldo Ulloa 2,1. (1) Oceanografía, Ciencias Naturales y Oceanográficas , Universidad de Concepción (2) Instituto Milenio de Oceanografía (3) Georgia Institute of Technology

Alteromonas is a copiothropic γ-proteobacteria with ecologicalrelevance in the ocean. In this work, we explore the distribution ofAlteromonas species through the coast of the Pacific Ocean with anemphasis in Oxygen Minimum Zones (OMZs). Using amplicon sequencevariants (ASVs) for analyzing the statistics of co-occurrences withother species and their diversities across samples we characterizedthe different genetic variants of Alteromonas, allowing us to improvethe study of the distribution of this genus across the Pacific Ocean.We investigate the metabolic potential of Alteromonas in OMZs throughthe analysis of 19 Single Amplified Genomes (SAGs) obtained from theSouth Pacific Ocean OMZ as well as their potential interactions by theanalysis of metatranscriptomes from the study area. OneAlteromonas-ASV dominates in these systems, with a scarce detection inthe OMZs associated with high sulfur concentrations. Microbialcommunities in OMZs from the north and south Pacific oceans display ahigh similarity in terms of community structure, with clear patternsof co-occurrence between Alteromonas ASVs and important microbialmembers of low oxygen areas. Alteromonas SAGs recovered almost thecomplete core pangenome regardless of their phylogenetic affiliation,with unique genes related to two-component sensors, regulatoryelement, and sugar metabolism. A strong coupling between fermentationand Glyoxylate cycle was found in terms of transcriptomic activityunder low oxygen conditions. Our results expand our knowledge of thedistribution of these key microorganisms and their role in the carbonbiochemistry of marine low oxygen waters

Fondecyt postdoctorado Nº 3180724

211 Profiling of early-colonizers bacteria in soils of different ages following volcanic eruptions of Llaima volcano, Chile

Perfil de bacterias colonizadoras tempranas en suelos de diferentes edades luego de erupciones volcánicas en el volcán Llaima, Chile

Marcela Hernández4,1, Marc G Dumont2, Marcela Calabi 3, Tebbe Christoph1, Ralf Conrad 4. (1) Thünen Institute of Biodiversity, Germany (2) University of Southampton, United Kingdom (3) Universidad de La Frontera, Chile (4) Max Planck Institute for terrestrial Microbiology, Germany (Sponsored by Alexander Von Humboldt)

Volcanic eruptions provide a model to understand soil-forming processes and the role of pioneer bacteria as early colonizers. The objective of this study was to identify and characterize the microbial communities involved in soil formation. Soil samples were collected from Llaima volcano (Chile) at sites destroyed by lava in different centuries (1640, 1751 and 1957). Metagenetic analysis of bacterial 16S rRNA genes showed that the microbial profiles in the youngest soils (1957) were unusual, with a high abundance of bacteria belonging to the order Ktedonobacterales (Chloroflexi) in the 1957 soil (37 %) compared with the 1751 (18 %) and the 1640 soils (7 %). Other abundant phyla in the youngest soils included Planctomycetes (18 %) and Verrucomicrobia (10 %). On the other hand, Proteobacteria and Acidobacteria were highly abundant in the oldest soils (16 % in 1640 and 15 % in 1751 for Acidobacteria; and 38 % in 1640 and 27 % in 1751 for Proteobacteria). Ongoing research is examining the metagenomic profile of autotrophic bacteria, characterizing mostly CO-oxidizing genomes, and specifically targeting those from the order Ktedonobacterales. In this study, we showed that there is a gradual establishment of the microbial community in volcanic soils following an eruption and that specific microbial groups are able to colonize during the early stages of recovery.

Alexander von Humboldt Foundation and Max Planck Society, Germany

212 How random are bacteria metacommunity assemblages in a complex floodplain system?

Metacomunidades bacterianas de sistemas aluviales: ¿Cuánto de azar hay en su estructura?

Paula Huber1, Sebastián Metz2, Gisela Mayora 1, Fernando Unrein2, Melina Devercelli1. (1) Instituto Nacional de Limnología (INALI), UNL-CONICET. (2) Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (IIB INTECH), UNSAM-CONICET.

Determining which processes take place in the spatial distribution of bacterioplankton metacommunities has been a central goal of microbial ecology. In freshwater systems, selection has been spotted as the main driver shaping the structure of assemblages. However, its relative importance compared with other processes (i.e. dispersal, drift, speciation) may depend on spatial heterogeneity and dispersal rates within a metacommunity. Here,we design a spatio-temporal study in a complex floodplain system of Paraná River to investigate in which strength the deterministic and stochastic processes drive the structure of bacterial metacommunity. We hypothesized that the importance of the different processes depends mainly on hydrological connectivity that determines the environmental heterogeneity (EH). We used an analysis based on phylogenetic and taxa turnover and co-occurrence networks. We predicted that, as hydrological connectivity increases (i) bacterioplankton metacommunity is mainly driven by drift, leading to (ii) random associations between bacterial taxa. Contrary, we found that selection was the main driver of bacterial metacommunities regardless of hydrological periods. However, its relative importance as well as the type of selection, changed according to the EH. Homogeneous and heterogeneous selection had the major role in structuring the metacommunity in periods of high and low EH, respectively. However, in the period of intermediate EH, the relative importance of non-selection processes were twice as high as those of other periods. Additionally, changes in hydrological conditions significantly affected the associations between bacterial zOTUs being more random in the period of intermediate EH.

PICT- 201-0465. PI: Dra. Devercelli M. INALI. Argentina. PICT 2012-2016. PI: Dra. Marchese M. INALI. Argentina.

213 Understanding the effects of land use and soil type on the structure of soil bacterial communities in the Brazilian Western Amazonia

Conociendo los efectos del uso de la tierra y el tipo de suelo sobre la estructura de las comunidades bacterianas del suelo en la Amazonia Occidental brasileña

Fernando Igne Rocha1, Thiago Gonçalves Ribeiro2, Ederson Da Conceição Jesus3. (1) Departamento de Solos, Instituto de Agronomia, Universidade Federal Rural do Rio de Janeiro (2) Universidade Federal Rural do Rio de Janeiro (3) Embrapa Agrobiologia

The deforestation promoted by the extensive cattle ranching is considered one of the most influential factors of biodiversity loss in the Brazilian Amazon. Nevertheless, the environmental factors having a greater impact on microbial groups and their functional traits in Amazon soils remain still underexplored. We aimed to identify the relationship between land use and soil type on the structure of soil bacterial communities in Western Amazon. Bacterial communities were assessed through sequencing of the 16S rRNA gene in the MiSeq platform. Sitesof importance for conservation were selected in the States of Amazonas and Acre. Amplicon Sequence Variants were identified and processed in the R environment by using the DADA2 algorithm. Land use explained 43% of the total variation of the bacterial data, indicating that community structure was affected mainly by land use (PERMANOVA, p <0.001). The Proteobacteria (39.4%), Acidobacteria (32.6%), and WPS2 (3.4%) prevailed in forests, and Actinobacteria (20.6%), Verrucomicrobia (13.4%), and Firmicutes (5.0%) in pastures. Thirty percent of the variation within the same land use could be attributed to specific soil attributes (PERMANOVA, p <0.001) such as base saturation andsoil texture. The structure of soil bacterial communities differed between sites with highly and less weathered soils.

USAID, CNPq

214 Indicator microorganisms and pathogens in indirect reuse water for irrigation, Rocha River, Cochabamba, Bolivia

Microorganismos indicadores y patógenos en aguas de reúso indirecto en riego, río Rocha, Cochabamba, Bolivia

Maria De Las Mercedes Iriarte-Puña, Licyel Lenny Paulas Condori1, Javier Orellana Salazar1, Ana María Romero Jaldín1. (1) Centro de Aguas y Saneamiento Ambiental, Ciencias y Tecnología , Universidad Mayor de San Simón (Sponsored by Universidad Mayor De San Simón)

Factores como el cambio climático, la escasez de agua y el incremento poblacional están marcando tendencias en todo el mundo, sobre todo en Latino América, del uso de agua residual para riego de cultivos, actividad que incrementa la productividad debido a los contenidos en nutrientes orgánicos. Sin embargo, el uso inadecuado conlleva un riesgo elevado para la salud pública por patógenos intestinales y transmisión de enfermedades. No existe en Cochabamba una información sistematizada del comportamiento de microorganismos indicadores y patógenos en el agua del rio Rocha, muy contaminado y fuente primaria de riego de hortalizas. Este estudio evaluó la presencia y concentración de microorganismos en el agua del rio Rocha y de riego de cultivos, a través del tiempo. Los resultados de análisis fueron sistematizados y evaluados. Aquí se revela que a lo largo de los últimos años, coliformes fecales se mantienen en una concentración fuera de norma para descargas líquidas, encontrándose huevos de helmintos, Giardia, Cryptosporidium, indicadores virales y patógenos en concentraciones que implican alto riesgo para transmisión de enfermedades. La contaminación constante a lo largo de los años deberá llamar la atención de autoridades y agentes de toma de decisiones. Se encontró una concentración más baja del virus del pimiento y de Bacteroides 2.9 y 5.5 unidades log10 respectivamente en pozos de filtración a la ribera del rio Rocha, este recurso se presenta como una opción de tratamiento en el reúso indirecto del agua de rio, por lo que contribuirá en la disminución del riesgo por contaminación microbiológica.

Partnerships for Enhanced Engagement in Research Science program, under Sub-Grant No. PGA-2000001988. Universidad Mayor de San Simón

215 Adenovirus´ detection by nested-pcr in wastewater treatment plants and receiving water bodies, Cochabamba, Bolivia

Detección de adenovirus por nested-pcr en plantas de tratamiento de aguas residuales y cuerpos receptores, Cochabamba, Bolivia

Melizza Fuentes1, Maria De Las Mercedes Iriarte-Puña1, Alfredo Soliz1, Pablo Alfaro2. (1) Centro de Aguas y Saneamiento Ambiental, Ciencias y Tecnología, Universidad Mayor de San Simón (2) Departamento de Biología, Ciencias y Tecnología, Universidad Mayor de San Simón

El vertido de aguas residuales tratadas sobre cuerpos receptores y el uso para distintas actividades comoriego, consumo y otros, se ha convertido en una actividad frecuente debido a la escasez de agua en Cochabamba. La deficiencia en el tratamiento de aguas residuales provoca que el efluente no cumpla los requisitos para descargas líquidas, presumiéndose la presencia de patógenos causantes de enfermedades. Los adenovirus, causantes de gastroenteritis infantil, contribuyen al 5% de la mortalidad anual en Bolivia, siendo una amenaza a la salud pública por su difícil eliminación en procesos de tratamiento. Nested-PCR es una técnica de detección de adenovirus aún poco explorada en nuestro medio y se presenta en este trabajo como una alternativa potencial para ser incluida en programas de monitoreo. El objetivo de este trabajo fue la detección de adenovirus en aguas provenientes de cinco plantas de tratamiento que vierten efluentes sobre cuerpos receptores. Para ello, se realizó una extracción y amplificación del ADN; que comprende dos rondas de amplificación con distintos pares de cebadores cada una. Se confirmó la presencia de Adenovirus humano tipo 40 en muestras de aguas de efluentes hacia ríos y vertientes, y ausencia en pozos aledaños. Esto demuestra que no existe un correcto funcionamiento de las plantas de tratamiento además de no contar con una tecnología adecuada para la remoción de patógenos virales; necesitándose así análisis cuantitativos de concentración y evaluación dosis-respuesta del patógeno para completar estudios de riesgo y con ello coadyuvar en la prevención y mejora de la salud pública.

Universidad Mayor de San Simón - ASDI Cooperación Sueca

216 Microbial diversity across Río Agrio, an extremely acidic natural model system of interest for bioleaching

Diversidad microbiana a través de Río Agrio, un sistema de modelo natural extremadamente ácido de interés para la biolixiviación

Francisco Luciano Issotta1, Dilanaz Arisan1, Ana Moya-Beltrán1, Matías Castro1, Héctor Carrasco1, Yasna Gallardo1, Ricardo Ulloa2, Patricia Chiacharini 2, Alejandra Lima3, Barrie D Johnson4, Sofía Urbieta3, Edgardo Donati3, Alejandra Giaveno2, Raquel Quatrini5,1. (1) Laboratorio de ecofisiologia microbiana, Fundación Ciencia & Vida (2) PROBIEN, Universidad Nacional del Comahue (3) CINDEFI, Universidad Nacional de La Plata (4) School of Natural Sciences, Bangor University (5) Millennium Nucleus in the Biology of the Intestinal Microbiota (Sponsored by Raquel Quatrini)

Background: The Copahue-Caviahue geothermal (CCG) system is a natural extreme environment located in the Andes mountain, Argentina. Two hydrothermal springs near the Copahue volcano crater are the source of an acidic watershed of unique characteristics in South America named Río Agrio (RA). Along its journey from the source to Lake Caviahue and downstream, this river features an ample gradient of pH (pH 1.5–8.5), temperature (10-50ºC) and conductivity (5-20000 µS/cm).

Objectives: Directed metagenomics (DMG) of the RA gradient was used to assess the prokaryotic microbes distribution, abundance and diversity. These results were analyzed in the context of the hydrogeochemical features of the sampling points.

Methods: Microbial biomass was recovered across the basin of the river for total DNA extraction, PCR and amplicon sequencing (16S RNA gene). Samples were collected at points were pH, temperature and conductivity could be registered.

Results:Different niches were distinguished along the gradient. DMG data generated provided new insights into the community structure in these niches and the composition and diversity changes occurring along the river. The occurrence and distribution patterns of several microbial acidophiles were defined, along with their microdiversity in distinct niches. The major taxa (Genus) found was Acidiphilium, Acidocella and Microbacter. This work sets the basis for further studies aiming to explore the eco-evolutionary processes that shape this ecosystem.

Funding: CONICYT scholarship 21160871 (FI); Fondecyt 1181251 (RQ); Basal AFB170004 (RQ); Millennium Science Initiative, Ministry of Economy, Development and Tourism of Chile under Grant “Millennium Nucleus in the Biology of the Intestinal Microbiota”.

217 Microbial community responses in a chemically stressed freshwater ecosystem: do chemical mixtures play a role?

Respuesta de la comunidad microbiana en un ecosistema de agua dulce químicamente estresado: ¿Juegan un rol las mezclas de químicos?

Gerdhard L. Jessen1, P.A. Inostroza2, R.A. Quiñones4,3, C. Gallardo4, X. Zhang5, M. Krauss6, W. Brack6,7, T. Backhaus2. (1) Instituto de Ciencias Marinas y Limnológicas, Ciencias, Universidad Austral de Chile (2) Department of Biological and Environmental Sciences, University of Gothenburg (3) Department of Oceanography, University of Concepción (4) Interdisciplinary Center for Aquaculture Research (INCAR), University of Concepción, Concepción, Chile (5) State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University (6) Department of Effect-Directed Analysis, Helmholtz Centre for Environmental Research - UFZ (7) Institute of Biology V, RWTH Aachen University

Anthropogenic activities, such as agriculture, industrial/mining operations, and wastewater treatment plant discharges are considered the main sources of chemicals into the aquatic ecosystems. These contaminants affect biodiversity patterns and modify ecological function at different ecosystem levels. In case of microbial communities - main drivers of key biogeochemical cycles in freshwaters ecosystems- acute copper concentrations inhibit carbon fixation, causes oxidative stress, and ultimately inhibits cell growth. For antibiotics, even residues can favour the selection of resistant microorganisms and consequently affecting microbial activity. Although natural communities are usually exposed to pollutant mixtures of diverse toxicity, the classic single-pollutant approach to evaluate the toxicological effect of chemicals ignores its combined action. In particular, the microbial community response is poorly constrained with respect to mixture toxicity responses. Here, we investigate the interplay between complex chemical mixtures and microbial community structure through the River Aconcagua ecosystem in Chile. Samples from reference, tributary and river sites were analysed for a wide range of organic and inorganic pollutants. Preliminary results identify a series of metals and pesticides contributing the most to the total mixture toxicity. rRNA gene amplicons (Bacteria and Eukarya) sequencing will be combined to assess how the community is structured in this chemically stressed freshwater ecosystem and the role that chemical mixtures play. These results will provide new insights into ecosystem responses to contaminants and help to bridge the gap about the role of complex chemical mixture on the microbial community

218 Isolation and Identification of Psychro-metal(oid)-tolerant Bacteria from Antarctic

Aislamiento e Identificación de Bacterias Antárticas Psicro-Metalo(oide) Tolerantes

Pablo Jiménez Aliaga1, Gerardo Retamal Morales1, Gloria Levicán1. (1) Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile

Recent studies in Antarctica have reported high levels of toxic metals and metalloids caused by anthropogenic sources. This situation added to its extreme conditions, such as low temperatures, high UV radiation levels and high metal(oid) concentration could indicate the presence of poly-extremophile microorganisms with biotechnological potential for toxic metal(loid) decontamination. In this study, soil and water samples were collected from Marian Cove and Fildes Bay locations in Antarctica. Samples were cultured in ABM and marine agar at 4º, 20º and 37º C, obtaining a total of 108 isolates. The most tolerant strains were selected by evaluating their ability to grow in ABM agar supplemented with 1, 5 and 10 mM of NaAsO2; with the same concentrations for CuSO4; and 10, 100 and 500 μM of HgCl2. Twenty- two selected strains were used to study their minimal inhibitory concentration (MIC), and were identified by the sequencing of 16S rRNA gene, where taxonomic classification and phylogeny was determined. Also, siderophore- production was evaluated. Isolates from the Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes phyla were the most abundant in the collection. Among these, isolates M2.1, M1.2, M2.4, M8.5 and M10.14 showed high arsenic-tolerance, with MIC values up to 7.8 mM. Regarding copper-tolerance M2.4 showed highest tolerance of

12 mM for CuSO4 and high siderophore production, while for mercury M10.14 showed the highest tolerance value reaching up to 312 µM of HgCl2. Overall, these findings allowed the identification of psychro- and metal(loid)-tolerant microorganisms and highlight promising candidates for biotechnological applications. Keywords: Extremophiles, metal tolerance, Antarctica, arsenic, copper, mercury.

This work was funded by Fondecyt 1170799; INACH RT31-16 Grant from government of Chile, Dicyt-USACH, and Basal project USA1799/1555/1498 from USACH

219 Effects of deletion of circadian clock genes in Anabaena sp. PCC7120

Efectos de la deleción de genes del reloj circadiano en Anabaena sp. PCC7120

Javiera Jiménez1, Marcial Silva2, Mónica Vásquez2. (1) Universidad de Chile (2) Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica de Chile

In unicellular cyanobacteria has been demonstrated that the circadian clock influences the timing of certain cellular processes such as photosynthesis, cellular respiration and cell division. This regulation requires the presence of the central oscillator KaiABC to predict and anticipate environmental changes to optimize the cellular response. Studies on unicellular organisms have demonstrated the gating of cell division by the circadian clock, and the oscillation of several genes, but studies on multicellular cyanobacteria have been scarce, nonetheless, clock-controlled genes specific to heterocyst have been identified. Despite progress in understanding the factors that orchestrate cellular division, the proteins that participate and how the process occurs in multicellular cyanobacteria are still unknown, and the functional clock´s physiological and metabolic relevance has been underexplored. To evaluate the effects of the circadian clock in filamentous cyanobacteria, we generated and characterized a mutant ofAnabaena sp. PCC7120 by deletion of the kaiABC cluster through homologous recombination.

During the segregation of the kaiABC mutant, we observed that the filament’s morphology was not as the wild- type but branched filaments characteristic of the Stigonematales order. When the segregation was complete, the morphology was similar to the wild type, with the capacity to differentiate heterocysts still present, although heterocyst’s patterning seems affected which suggests an underlying control of cell differentiation by the circadian clock. The transient branched phenotype suggests that branching in cyanobacteria is not dependent of the presence of particular genes but is controlled by differential expression of cell division genes, in this case, influenced by the KaiABC oscillator. Fondecyt #1161232

220 High-level ecological processes driving microbial community structure in distinct depth layers of the global ocean

Procesos ecológicos de alto impacto que impulsan la estructura de la comunidad microbiana en distintos niveles de profundidad en el océano global

Pedro C. Junger1, Hugo Sarmento1, Caterina R. Giner2, Mireia Mestre4,2,3, Marta Sebatián5, Cèlia Marrasé2, Carlos M. Duarte6, Silvia G. Acinas2, Ramon Massana2, Josep M. Gasol2, Ramiro Logares2. (1) Departamento de Hidrobiologia (DHB), Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de São Carlos (UFSCar) (2) Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM, CSIC) (3) Centro FONDAP de Investigación en Dinámica de Ecosistemas Marinos de Altas Latitudes (IDEAL) (4) Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile (5) Oceanography and Global Change Institute (IOCAG), University of Las Palmas de Gran Canaria (6) King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia (Sponsored by Malaspina-2010 Expedition (CSD2008-00077, MINECO, Spain))

Microbes play essential trophic and biogeochemical roles from surface to bottom waters of the ocean. Understanding the underlaying mechanisms responsible for their distributions is fundamental to predict how they will respond to environmental change. A recent synthesis in community ecology indicates that four high-level processes determine the structure of communities: selection, dispersal, drift and speciation. Recent studies have determined that the relative importance of these mechanisms in structuring prokaryotic and picoeukaryotic communities in surface waters of the global ocean is different: while prokaryotes are shaped by a balanced combination of dispersal, selection and drift, picoeukaryotes are mainly driven by limited dispersal. However, it is still unknown whether the relative importance of these ecological processes change with depth at the global scale. Here, we aim to quantify the effects of these processes on marine microbial assemblages at the epi- (0-200m), meso- (200-1,000) and bathypelagic (1,000-4,000 m) layers of the ocean. To do so, we used 16-18S rRNA gene amplicon sequence variants from both prokaryotes and picoeukaryotes collected during global or regional expeditions covering the tropical and subtropical global ocean as well as the Mediterranean Sea. We hypothesize that the role of selection in structuring microbial assemblages in each of these depth layers is different due to a potential decrease in habitat heterogeneity with depth (i.e. potential decrease in selective pressure). Furthermore, we hypothesize that the importance of dispersal will change with depth, given the decrease in current speed with increasing depth and the possibility of aerial dispersal in surface waters.

This work was supported by the projects Malaspina-2010 Expedition (CSD2008-00077, MINECO, Spain) and INTERACTOMICS (CTM2015-69936-P, MINECO, Spain).

221 Rhodobacter Rb3 response to UV-R assessed by the recA gene: Laboratory vs. Antarctic

Evaluación de la respuesta de Rhodobacter sp. a estrés inducido por radiación UV mediante el gen recA: Laboratorio vs. Antártica

Lenka Kurte1,2, Vilma Pérez2,3, Cristina Dorador 4,5, Verónica Molina6, Martha Hengst2,4. (1) Programa de Magíster en Ciencias, mención Biodiversidad y Conservación, Universidad de Valparaíso (2) Laboratorio de Ecología Molecular y Microbiología Aplicada , Ciencias Farmacéuticas, Universidad Católica del Norte (3) Australian Centre for Ancient DNA, University of Adelaide, Australia (4) Centro de Biotecnología y Bioingeniería, Universidad de Chile (5) Laboratorio de Complejidad Microbiana y Ecología Funcional , Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (6) Observatorio de Ecología Microbiana , Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha

La Antártica es uno de los ecosistemas más extremos de Chile, y una de las zonas más afectadas por el adelgazamiento de la capa de ozono, produciendo un ambiente excepcional para estudiar los efectos de la radiación solar; la cual ha sido establecida como uno de los principales factores de estrés ambiental en los seres vivos, causando daño directo e indirecto en el ADN. El objetivo de este trabajo fue determinar la respuesta de Rhodobacter Rb3, a la exposición RUV. Los experimentos fueron realizados bajo condiciones de laboratorio utilizando lámparas de radiación UV-B, y en la Antártica con diferentes tratamientos (PAR, PA, NEGRO y NATURAL). Se determinó su respuesta a través de viabilidad celular, incorporación de 3H-Leucina y la cuantificación de la expresión del gen recA por qPCR. Los resultados demostraron que en los tratamientos control utilizados en ambos experimentos, existe una mayor expresión del gen recA, lo que sugiere la existencia de una respuesta al estrés inducido por radiación UV independiente de este gen. Por otro lado, en los ensayos de viabilidad celular (UFC), se observó una mayor sobrevivencia en los tratamientos control, disminuyendo en los tratamientos RUV-B y PA. Además, en los ensayos de tolerancia, se observó una relación inversa entre la viabilidad celular y la dosis de RUV-B. Esta investigación contribuye al conocimiento de los mecanismos de respuesta a RUV utilizados por bacterias, que crecen naturalmente en una de las zonas de mayor radiación del planeta, como el altiplano chileno

Fondecyt N°: 1100953; 1140179; 1140356, 1181773, 1171324, FB-0001; INACH ECA-52; ELAC/DCC-0178; AT15-2-01, Programa Magíster en Ciencias, mención en Biodiversidad y Conservación

222 Red bioactive pigment as antimicrobial compound obtained from three Serratia proteamaculans isolates: chemical, bioactivity and genetic analysis

Pigmento bioactivo rojo como compuesto antimicrobiano, obtenido desde tres aislados de Serratia proteamaculans: análisis químico, bioactivo y genético

Mijali Lampidis2,1, Martha B. Hengst3,2. (1) Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad De Antofagasta (2) Laboratorio de Ecología Molecular y Microbiología Aplicada, Departamento de Ciencias Farmacéuticas, Facultad de Ciencias, Universidad Católica del Norte (3) Centro para Biotecnología y Bioingeniería (CeBiB)

La prodigiosina es un pigmento rojo aislado por primera vez en la década del 30’ desde Serratia marescens. Es un compuesto tripirrólico que cuenta con variadas propiedades bioactivas, como antibacteriano, antifúngico, antiprotozoario, anticáncer, inmunosupresor, entre otras. El objetivo del trabajo fue determinar las propiedades antibacterianas y caracterizar la ruta de biosíntesis del pigmento rojo en tres aislados de Serratia proteomaculans con características fenotípicas diferentes: dos cepas aisladas desde una vertiente en la quebrada de Paposo (Región de Antofagasta) y una desde una laguna cercana a Neltume (Región de Los Ríos), e identificadas por secuenciación del gen 16S ARNr. El compuesto fue extraído con acetato de etilo acidificado al 4% con HCl, desde cultivos de S. proteomaculans escalados a un litro y fueron analizados por HPLC/UV-VIS/MS, determinándose que el pigmento corresponde a prodigiosina. La capacidad antibacteriana de los extractos se evaluó frente a dos cepas patógenas mediante el método de resazurina, estas fueron Bacillus subtilis y Staphylococcus aureus. La identificación de la ruta de biosíntesis de prodigiosina se realizó mediante los genes pigC y pigP, clave en la producción de prodigiosina. Los resultados demuestran la producción de prodigiosina en cepas ambientales de Serratia aisladas del desierto costero del Norte de Chile, con actividad antagonista contra dos patógenos de importancia clínica

Proyectos FB0001 (CEBIB), DAAD-CONICYT Nº 2011-698, Fondecyt Regular N° 1140179, BMBF-CONICYT (CHL12WTZ-020), FDI Línea de Emprendimiento Estudiantil Nº ANT1704 2018, Beca Tesis de Pregrado Universidad de Antofagasta 2018

223 Anaerobic digestion vs co-digestion: start-up and active microbiome analysis

Digestión anaerobia vs co-digestión: puesta en marcha y estudio del microbioma activo

Céline Lavergne2, Patricia Bovio-Winkler1, Claudia Etchebehere1, Santiago García-Gen3. (1) Laboratorio de Ecología Microbiana (Departamento de Bioquímica y Genómica Microbiana), Instituto de Investigaciones Biológicas Clemente Estable (Uruguay) (2) Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso (3) Departamento de Ingeniería Química y Ambiental, Universidad Técnica Federico Santa María

La co-digestión anaerobia (coDA) es la digestión simultánea de dos o más residuos orgánicos, un proceso biológico catalizado por diferentes grupos de microorganismos que transforma la materia orgánica en biogás. Una de las ventajas potenciales de la coDA es hacer más costo-eficientes las actuales plantas de biogás, al centralizar el tratamiento de residuos en una misma instalación. Se realizaron dos series de experimentos consecutivos de arranque de 79 y 90 días de operación en reactores (escala de laboratorio) utilizando una secuencia de arranque optimizada anteriormente. Se observaron rendimientos similares entre el sistema de mono-digestión anaerobia (con lodos activos) y el sistema de coDA (lodos activos y purín porcino) (más del 50% de la materia orgánica se transforma en metano). Por otro lado, se obtuvo una mejora del rendimiento entre la primera serie y la segunda serie, indicando una adaptación del inóculo. La diversidad activa de las Bacterias y Arqueas (secuenciación masiva de los transcriptos de la región V4 del gen ARNr 16S) reveló una gran diversidad de microorganismos activos que proviene en mayor parte del inóculo. Se observó una colaboración entre las bacterias del género Defluviitoga, generadoras de ácido acético, y las arqueas metanogénicas (representando hasta 4,6% de la comunidad activa total) y dominadas por las Methanosarcinales. La incorporación de un co-sustrato (no tóxico) en pequeñas proporciones (hasta 8% en volumen) no modifica sustancialmente la composición microbiana activa comparada con la mono-digestión y, por tanto, éste puede mantener su actividad normal y así optimizar el tratamiento de varios residuos simultáneamente.

Proyecto Conicyt-PAI (PAI77180062) de Dr. Santiago García-Gen

224 Role of methanogenic archaea in the biogeochemical cycle of mercury in natural and anthropic anaerobic ecosystems

Rol de las Arqueas metanogénicas en el ciclo biogeoquimico del mercurio (Hg) en ecosistemas naturales y antropicos anaerobios

Céline Lavergne1, Lars-Eric Heimburger2, Léa Cabrol2, Rolando Chamy1. (1) Escuela Ingeniería Bioquímica , Laboratorio de Biotecnología Ambiental, Pontificia Universidad Católica Vaparaíso (2) CNRS, IRD , Mediterranean Institute of Oceanography (MIO, UM 110), Aix-Marseille University, Univ Toulon (Sponsored by Rolando Chamy)

The methylmercury has the feature, in addition to its high toxicity for living organism, to be easily incorporated, bioaccumulated in living organisms and biomagnified through the food web. Terrestrial aquatic systems (e.g. lakes) are natural deposits of contaminants. Recently, the microorganisms implicated in the transformation of methylmercury in aquatic systems have been found much more diverse than previously thought. Among them, 9 methanogenic Archaea strain are able to methylate the mercury in pure culture. However, few proofs exist in-situ in aquatic systems. Pristine Antarctic lakes (South Shetland Islands, Antarctic), sub-Antarctic beaver ponds (Tierra del Fuego, Chile), wetlands of the Central region of Chile and anaerobic reactors were sampled as representing a gradual anthropic impact. Accordingly, we found 150 times more total mercury in human impacted zones than in pristine Antarctic lakes. Also, the archaeal community was more important in anthropic systems reaching 20% of the microbial community. Interestingly, some Archaea from the Bathyarchaeia class were more active (high-throughput sequencing of the transcripts of the 16S rRNA gene) than present (16S rRNA gene) underlying their crucial role in lake sediments. For the first time in these ecosystems, microbial mercury methylation and methylmercury demethylation activities were performed by addition of enriched stables isotopes of inorganic mercury and methylmercury, respectively and we expect to find highest methylation rates in the anoxic, rich-organic matter ecosystems such as beaver pond and wetlands. In a context of increasing releases of heavy metals in aquatic environments, these findings could then be applied in some bioremediation water-treatment systems.

ECOS C16B03, FONDECYT Postdoc nº3180374 MEMARC, Apoyo Terreno INACH Resolución exenta nº647

225 Draft genome comparison of two Antarctic Streptomyces fildesensis strains: a promising specie for novel antimicrobials

Comparación genómica de dos cepas antárticas de Streptomyces fildesensis: una especie prometedora para nuevos compuestos antimicrobianos

Paris Lavin1, Eduardo Acosta2, Pablo Aran2, Cristina Purcarea3, C. M. V. L. Wong4, Cristina Dorador1. (1) Departamento de Biotecnología, Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta (2) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, , Universidad de Antofagasta (3) Department of Microbiology, Institute of Biology, Bucharest, Romania, Institute of Biology (4) Biotechnology Research Institute, Universiti Malaysia Sabah

During the first time that penicillin was tested on humans in 1941, the Fleming team had not enough of the drug to see the patients through to a full recovery. Today, almost 80 years later, the high production and the indiscriminate use of antibiotics contribute to the global rise of multidrug-resistant bacteria. Nowadays, it has been argued that the chances of discovering novel bioactive compounds is exhausted due to over-exploration in cosmopolitan areas. Thus, targeting microorganisms in extreme environments to avoid redundancy in the isolation of compounds has become important. Therefore, it has been hypothesized that antarctic bacteria could be a potential sources of novel compounds by the mere existence of novel and diverse metabolic pathways selected by evolutionary pressures present in the Antarctic environments. Previous studies on psychrotolerant AntarcticStreptomyces fildesensis strain had shown the capability to produce antimicrobial compounds inhibiting foodborne pathogens. On the present study we exhibit the comparison of two genomes of these species based on biosynthetic gene clusters predictions (BGCs). The whole draft genome (9.47 Mb and 9.38 Mb) analysis by Antismash 5.0 showed a total of 36 and 33 BGCs, respectively. Of these, 15 clusters are shared between the studied subjects, 21 and 18 clusters are exclusive of each strain. From a total of 34 new predicted biosynthetic gene clusters, 17 of each strain, with very low similarities with other known BGCs. These results highlight the potential of the Antarctic Streptomyces fildesensis species as a promising source of novel compounds.

226 Natural pyrene-degrading consortium selection and characterization of its diversity by high- throughput sequencing

Obtención de un consorcio natural degradador de pireno y caracterización de su diversidad por secuenciación de alto rendimiento

Florencia Layun1, Sabrina Festa1, Esteban Nieto1, Irma S Morelli2,1, Bibiana M Coppotelli 1. (1) Laboratorio de Biodegradación Microbiológica de hidrocarburos, CINDEFI (CONICET-UNLP) (2) CIC-PBA

La estabilidad, robustez, diversidad taxonómica y redundancia funcional de los consorcios son características claves que le otorgan flexibilidad al realizar una función metabólica. El objetivo de este trabajo fue seleccionar un consorcio degradador de pireno, conocer su capacidad degradadora y caracterizarlo en función de su estructura y composición. Se obtuvo un consorcio degradador de pireno (enriquecimientos sucesivos con 2000 mg.l-1 de pireno) y se conservó a -80ºC, al consorcio reactivado se lo llamó EF18P. Se realizó una cinética de degradación de pireno durante21 días (HPLC) encontrando eliminación del 94,9%. Para estudiar su diversidad se analizó el gen 16S rRNA (illumina MISeq-Qiime 1-PICRUSt). Se encontró una predominancia de los filos Proteobacteria y Bacteroridetes (90,84% y 8,63% respectivamente), siendo el géneroPseudomonas quien presentó mayor abundancia relativa (81,86%) y quien contribuyó en mayor proporción a los genes que codifican enzimas dioxigenasa. En el consorcio se encontraron genes relacionados con la ruta de degradación de pireno (PAH-RHDα GN y nidA). Se aislaron e identificaron, mediante secuenciación del gen 16S rRNA, 8 cepas bacterianas, todas pertenecientes al género Pseudomonas sp. Se estudió su capacidad degradadora de pireno en medio sólido y se observó halo de solubilización en 3 de las cepas aisladas. Se logró obtener y caracterizar un consorcio degradador de pireno, un PAH de alto peso molecular, que podría ser un buen candidato como inoculante en estrategias de bioaumento y como modelo de estudio de la biodiversidad de microorganismos encargados de la degradación de pireno.

PICT 2013-0103 Agencia Nacional de Promoción Científica y Tecnológica

227 Genome plasticity of the cellulose pellicle-forming bacterium Komagataeibacter xylinusATCC 23768 underlies the reversible transition to a free-living lifestyle

La plasticidad genómica de la bacteria formadora de películas de celulosa,Komagataeibacter xylinus ATCC 23768, determina la transición reversible hacia un estado celular de vida libre

Martín Céspedes1,2, Carlos Farkas3,4, Danilo Pérez-Pantoja3,4, Thomas Ledger1,2. (1) Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Chile (2) Center of Applied Ecology and Sustainability (CAPES). Chile (3) Genomics and Applied Microbiology for Biodegradation and Bioproducts (GAMBIO) CONICYT Research Ring. Chile (4) Programa Institucional de Fomento a la Investigación, Desarrollo e Innovación, Universidad Tecnológica Metropolitana, Chile

Bacteria of the genus Komagataeibacter produce large amounts of cellulose when grown in static batch cultures. Under such conditions, wild type cells develop within a floating polysaccharide pellicle, growing on the surface of the liquid medium, and no free-living cells are detected. However, when cultures are agitated, spontaneous mutant derivatives appear at high frequency. These free-living cells have lost the ability to produce cellulose, but can fully revert to a wild type phenotype when grown under static conditions. Although several genomes and cellulose-producing genes have been analyzed, no molecular explanation has been found for the reversible transition of Komagataeibacter to a free-living lifestyle. We have studied the genomic changes of K. xylinus ATCC 23768 during transition from wild type cells to cellulose-less mutants by comparison of repeat-based BOX-PCR patterns and plasmid profiles, confirming that similar changes in BOX patterns are observed in spontaneous mutants obtained independently, which suggests that transition is determined by programmed genetic changes. Furthermore, changes in the plasmid profile (2 plasmids of sizes 50 kbp and >260Kbp, respectively) were observed, suggesting genome-wide rearrangements have occurred. Finally, sequencing of the whole genome of strain ATCC 23768 showed that high identity repeat sequences are shared between the 3.37 Mbp chromosomal replicon and the 2 plasmids, which confirms a high potential for genome plasticity in K. xylinus.

This work was funded by the Center of Applied Ecology and Sustainability (CAPES) CONICYT PIA/BASAL FB0002 and CONICYT Research Ring ACT172128 (GAMBIO)

228 Ancient microbial messages to manipulate photosynthetic hosts: Molecular interactions between plant growth promoting rhizobacteria and the microalga Chlorella vulgaris

Mensajes microbianos antiguos para la manipulación de hospederos fotosintéticos: Interacciones moleculares entre bacterias promotoras de crecimiento de plantas y la microalga Chlorella vulgaris

Mario Álvarez1,2, Thomas Ledger1,2. (1) Center of Applied Ecology and Sustainability (CAPES). Chile (2) Laboratorio de Bioingeniería, Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Chile

Mutualistic interactions among bacteria and plants usually involve direct stimulation of plant growth by beneficial Plant Growth Promoting Rhizobacteria (PGPR). This can be achieved by modification of plant hormone levels when bacteria colonize plant tissues, or by signaling through volatile compounds of microbial origin, a strategy that does not require physical contact between the host and its bacterial partner. In this work, we have studied the interaction of four well-studied PGPR from different taxonomic origins with the fresh water microalga Chlorella vulgaris, in order to compare their effects with those on the model plant Arabidopsis thaliana. Using in vitro growth stimulation assays, we have shown that co-cultivation of Azospirillum brasilense Sp7, Paraburkholderia phytofirmans PsJN, Pseudomonas simiae WCS417r or Bacillus subtilis GB03 with Chlorella cells increases the growth rate and yield of liquid and agar- based microalgae cultures. Furthermore, we have observed that those effects are largely mediated by contact- dependent mechanisms in Sp7 and WCS417r, while the effects of PsJN are due to volatile signal production. This is consistent with the respective phytostimulation mechanisms of these bacteria in A. thaliana, which would suggest an evolutionary conservation of such host-bacteria interaction mechanisms among distant members of the Viridiplantae. However, the effects of B. subtilis GB03 volatiles on Chlorella vulgaris greatly differ from those on A. thaliana, resulting in the death of the microalgae under conditions that enhance Arabidopsis growth.

This work was funded by the Center of Applied Ecology and Sustainability (CAPES) CONICYT PIA/BASAL FB0002. We thank GreenBiofactory for Chlorella vulgaris

229 Through thick and thin: An in vitro study of the dynamics of bacterial interactions in plant rhizosphere by microscopy image analyses

En la abundancia y la escasez: Un estudio in vitro de la dinámica de interacciones bacterianas en la rizósfera de plantas usando el análisis de imágenes de microscopía

María Francisca Martinich1,2, Daniela Ruiz1,2, Daniela Orellana2,1, María Josefina Poupin1,2, Thomas Ledger1,2. (1) Laboratorio de Bioingeniería, Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Chile (2) Center of Applied Ecology and Sustainability (CAPES). Chile

Mutualistic bacteria colonizing plants usually concentrate at the rhizosphere of the host, where root exudates provide nutrients suitable for bacterial growth, and where most key beneficial interactions with the host take place. However, the approaches to analyze colonization are focused on merely quantifying numbers of bacteria (CFU) in a determined volume/mass of soil or agar sample, arbitrarily defined as the “rhizosphere”. Such strategies typically involve sample homogenization to release bacterial cells, which precludes characterization of spatial distribution of bacteria within the sample and the study of population dynamics in a small scale. In this work, we studied the growth dynamics of Paraburkholderia phytofirmans PsJN and Azospirillum brasilense Sp7 at the rhizosphere of A. thaliana in vitro by taking advantage of light microscopy detection of bacterial microcolonies in the agar substrate. Using an image analysis approach, we estimated rhizosphere colonization levels of either bacterium, finding similar values to those of traditional CFU quantification procedures. We detected relevant differences in spatial distribution among Sp7 and PsJN in the substrate surrounding plant roots, showing strain specific enrichment zones in the rhizosphere. Furthermore, a marked diversity in microcolony size is observed for both bacteria in relation to root zone: small, highly abundant microcolonies in the vicinity of root meristems, while larger, less-frequent colonies appear associated to “older” root tissues, which may reflect population responses to changes in exudate content associated to root growth This work was funded by FONDECYT Project 1190634 and the Center of Applied Ecology and Sustainability (CAPES) CONICYT PIA/BASAL FB0002

230 Arsenic-tolerant consortium efficiency in the bioleaching of a zinc mineral in the presence of arsenic

Eficiencia de un consorcio arsénico-tolerante en la biolixiviación de un mineral de zinc en presencia de arsénico

Maria Alejandra Lima1, Camila Castro1, María Sofia Urbieta1, Edgardo Donati1. (1) CINDEFI, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (50 y 115, La Plata, Buenos Aires, Argentina).

La aplicación de procesos biomineros se ha incrementado notablemente en las últimas décadas debido a las ventajas relativas respecto de las técnicas tradicionales. No obstante, el uso de microorganismos para biolixiviar y/o biooxidar minerales puede ser afectado seriamente por la inhibición producida por ciertas especies químicas que son liberadas durante el proceso; entre estas especies se destaca el arsénico que está presente en muchos minerales y que es un fuerte inhibidor de los microorganismos biolixiviantes. Por esa razón, resulta importante que los consorcios presenten alta tolerancia a arsénico. En este trabajo se muestra la eficiencia de la recuperación de zinc por biolixiviación en presencia de arsénico, utilizando un consorcio azufre oxidante que fue adaptado a crecer en altas concentraciones de arsénico. El consorcio se originó a partir de una muestra tomada en el sistema geotermal Caviahue-Copahue y estaba integrado principalmente por Acidithiobacillus. La muestra de mineral utilizada provenía de la mina Hualilán (San Juan) y contenía 8% p/p de zinc. Los experimentos se llevaron a cabo en frascos erlenmeyers con 100 mL de medio mineral (pH2) con 2% p/v de densidad de pulpa, a los cuales se adicionaron concentraciones crecientes (100- 200ppm) de As(III) o As(V). Los sistemas fueron incubados en agitación a 30°C. Incluso a las mayores concentraciones de arsénico, el consorcio logró recuperar un elevado porcentaje del zinc (40-50%) en 35 días. Estos valores de recuperación son similares a los alcanzados en biolixiviaciones de este mineral, en ausencia de arsénico, utilizando otros microorganismos como Acidianus copahuensisy Sulfobacillus thermosufidooxidans.

ANPCyT, PICT-2016-2535 y PICT-2015-0463

231 Evaluation of taxonomic and functional profiles of autotrophic and heterotrophic As-tolerant consortia recovered from Salto del Agrio (Neuquén, Argentina)

Evaluación de perfil taxonómico y funcional de consorcios autótrofos y heterótrofos arsénico- tolerantes recuperados de Salto del Agrio (Neuquén, Argentina)

Maria Alejandra Lima1, Francisco Issotta2,3, Ana Moya-Beltrán2,3,4, Francisco L. Massello1, María Sofia Urbieta1, Raquel Quatrini2,4, Edgardo Donati1. (1) CINDEFI, Facultad de Ciencias Exactas, Universidad Nacional de La Plata (50 y 115, La Plata, Buenos Aires, Argentina). (2) Microbial Ecophysiology Laboratory, Fundación Ciencia y Vida (3) Facultad de Ciencias Biológicas, Universidad Andrés Bello (4) Millennium Nucleus in the Biology of the Intestinal Microbiota

El Río Agrio recorre el sistema geotermal Caviahue-Copahue integrando un ambiente extremo natural caracterizado principalmente por sus aguas ácidas con alto contenido de azufre, hierro, como así también concentraciones fluctuantes de arsénico (1302-8,3 µg/L). Estas condiciones convierten este ambiente en una importante fuente de microorganismos extremófilos potencialmente valiosos en aplicaciones biotecnológicas industriales y ambientales. A la fecha, se desconoce la influencia del arsénico en estas comunidades y los procesos metabólicos en los que está involucrado.

En este trabajo se explora la estructura comunitaria y funcional de una muestra ambiental de la cuenca del Agrio (Salto del Agrio) mediante una aproximación metagenómica. Para esto, se realizaron distintos enriquecimientos (heterótrofo, acidófilo-autotrófico y anaeróbico) adaptados a altas concentraciones de As(III)/As(V), los que posteriormente fueron secuenciados. El análisis metagenómico de los consorcios H3(heterótrofo-AsIII-tolerante), H5(heterótrofo- AsV-tolerante), A3(autótrofo-AsIII-tolerante), A5(autótrofo-AsV-tolerante), N5(anaeróbico-AsV-tolerante), reveló que los géneros más abundantes fueron Micrococcus y Pseudomonasen los consorcios heterótrofos; Acidithiobacillus, Acidiphiliumy Thiomonasen acidófilos-autótrofos; y Thiomonasen el anaerobio. La presencia de genes implicados en el metabolismo de arsénico se evaluó mediante la búsqueda específica de familias de proteínas en la anotación funcional, encontrándose en todos los consorcios genes de transporte de arsenito (arsB/acr3) y arseniato-reductasa (arsC) y, en algunos casos, genes de arsenito-oxidasa (aio). Además, se encontraron enriquecidas las categorías funcionales asociadas a metabolismo/transporte de aminoácidos y carbohidratos, mecanismos de transducción de señales y producción/conversión de energía. Los resultados obtenidos sustentan la exploración de potenciales aplicaciones de los consorcios microbianos seleccionados en prácticas biotecnológicas de remediación ambiental y biominería.

ANPCyT(PICT-2016-2535/PICT-2015-0463). PEEPg (AUGM). CONICYT-PFCHA/Doctorado Nacional/21160871. CONICYT-PFCHA/Doctorado Nacional/21171049. Fondecyt 1181251. Basal AFB170004. Millennium Science Initiative, Ministry of Economy, Development and Tourism of Chile under Grant “Millennium Nucleus in the Biology of the Intestinal Microbiota”.

232 Identification and characterization of new genes of resistome inCerrado soil

Identificación y caracterización de nuevos genes de resistoma en sueloCerrado

Philippe De Castro Lins1, Débora Farage Knupp1, Ricardo Henrique Krüger1. (1) Biologia Celular, Biologia Microbiana, Universidade de Brasília

A soil microbiota presents a high diversity of microorganisms. Consequently, their unexplored ecological and physiological relationships have great potential for the discovery of new antibiotic resistance genes (ARGs). The dissemination and surveillance of these genes produce a catastrophic effect on public health since multidrug- resistant pathogens are able to resist the antibiotics available, in order to impair the treatment of infectious diseases. The metagenomic strategy, allied to bioinformatic analyzes, has the possibility to elucidate and to understand the relation between the genes and their function in the cell. In order to understand a potential soil resistance profile, metagenomic analyzes will be performed to establish the genetic profile of microbial samples from the Cerrado soil. The objective of this work is to explore the profile of ARGs in Cerrado soil, identifying the conserved regions and the characterization of proteins that promote resistance. To date the data, two libraries were used for isolation of clones resistant to new β-lactam antibiotics; 62 clones resistant to five of the nine antibiotics were selected, divided into two libraries in vectors pCF430 and pCCFOS. These clones were sequenced in the NGS methodology. We will also perform bioinformatics analyzes in software such as the ORFfinder, blatsp NCBI, CARD, ARDs. We have identified some possible genes related to the resistance of the clones, for example: beta-lactamases, antibiotics efflux, methyl transferases, dioxigenases.Thus, it is possible, not only, to identify new classes of existing ARGs, but also accelerate the discovery of new genes that encodes molecules with antimicrobial activity.

CAPES / CNPq / FAPDF

233 Carotenoid production and metabolite analysis of Archaea species from Atacama saline lakes by high resolution UHPLC-Q-orbitrap-Mass Spectrometry

Producción de carotenoides y análisis de metabolitos de especies de Archaea de lagos salinos de Atacama por espectrometría de masas de alta resolución UHPLC-Q-orbitrap

Catherine Lizama Jiménez1, Daniel Andrade Hidalgo1, Felipe Riveros1, Jorge Bórquez2, Mario Simirgiotis3. (1) Tecnología Médica, Facultad de Ciencias de la Salud, Universidad de Antofagasta (2) Departamento de Química, Facultad de Ciencias Básicas, Universidad de Antofagasta (3) Instituto de Farmacia, Facultad de Ciencias, Universidad Austral de Chile

Carotenoid pigments are an excellent source of antioxidant compounds and are increasingly required by the food and nutraceutical industry. The biomass for six strain of Archaea isolated from the Atacama desert lakes were lyophilized and the content of total carotenoids and the antioxidant capacity are analyzed. For this study UHPLC mass spectrometry was used, which is an excellent technique for the rapid analysis of organic compounds in organic materials, including Archaea (Simirgiotis et al., 2013). Sixteen carotenoids compounds were rapidly detected using high resolution LC-MS analysis and photodiode array detection (HPLC-Orbitrap-APCI-PDA-MS). In six lyophilized samples strains isolated from the Atacama desert lakes, the compounds were the C-50 antioxidant bacterioruberin, several of its isomers and derivatives. Samples were also analyzed regarding antioxidant activity and carotenoid content as the scavenging of the 1,1-diphenyl-2-picrylhydrazyl Radical (DPPH), radical ABTS, (ABTS), Total phenolic content (TPC), and Total carotenoid content (TCC) . Strain 86 showed the highest DPPH bleaching activity (16.13 ± 3.25 μmol Trolox/g extract) followed by strain 85 (35.43 ± 3.26) and strain 51 (49.84 ± 6.21). The content of carotenoids showed the same trend, (152.63 ± 3.35; 130.7 ± 3.22 and 112.05 ± 1.87 mg astaxanthin/g dry weight for samples 86, 85 and 51, respectively) as well as the other spectroscopic measurements.The results are consistent with the fact that the antioxidant activity comes from carotenoids

Agradecimientos: Proyecto BIP 30320522-0 fondequip EQM140002. Network for Extreme Environments Research project (NEXER Project (ANT1756)), Universidad de Antofagasta, Chile.

234 Prokaryotic biodiversity of Río Agrio, Neuquén, Argentina

Biodiversidad procariota en el Río Agrio, Neuquén, Argentina

Germán A. López Bedogni1, Francisco L. Massello1, María Sofía Urbieta1, Edgardo Donati1. (1) CINDEFI, Facultad de Ciencias Exactas, Universidad Nacional de La Plata

Los microorganismos extremófilos son, desde hace varios años, objeto de exhaustiva investigación por su capacidad de vivir en condiciones muy alejadas a las de la vida humana. En este trabajo se muestra la biodiversidad procariota en el Río Agrio, un río naturalmente ácido, que se origina a partir de dos surgentes geotermales muy cerca del cráter del volcán Copahue, en el sistema geotermal Copahue-Caviahue ubicado en el noroeste de la provincia de Neuquén en la Patagonia Argentina. En su recorrido inicial el Río Agrio tiene un pH entre 1 y 2 y, a pesar de recibir diferentes cursos tributarios principalmente de deshielo, mantiene su bajo valor de pH incluso luego de atravesar el lago Caviahue. Para este trabajo se recolectaron muestras de agua en puntos representativos a lo largo del curso del río, desde las nacientes hasta la gran cascada llamada Salto del Agrio, 15 Km río abajo. A partir de éstas se realizó la extracción de ADN, la secuenciación masiva de un fragmento del gen 16S ARNr y el posterior análisis bioinformático utilizando el paquete MOTHUR y comparando contra la base de datos SILVA. Los resultados mostraron que en la primera parte del río las especies dominantes son acidófilos, mesófilos, hierro y azufre oxidantes, de los géneros Acidithiobacillus, Ferroplasma y Sulfobacillus; en cambio, en Salto del Agrio donde el pH asciende a 3, se encontró mayor riqueza y heterogeneidad de especies siendo los grupos más representativos Geothrix y Candidatus Wolfebacteria.

ANPCyT, PICT-2016-2535 y PICT-2015-0463

235 Heterotrophic flagellates sorting optimization for genome sequencing from broad range salinity aquatic systems (marine and high-altitude saline wetland)

Optimización de la selección de Flagelados Heterótrofos en sistemas acuáticos de amplio rango de salinidad (ambientes marinos y salares) para secuenciación del genoma

María Francisca Luza-Miric1,2, Cristina Dorador1, Raquel Rodríguez-Martínez1. (1) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta (2) Universidad de Antofagasta

Heterotrophic flagellates are small unpigmented protists playing an important ecological role as bacterial grazers and nutrient remineralizers in aquatic ecosystems. Moreover, this heterotrophic microbial diversity is mostly uncultivated, and it has been understudied in saline systems. Therefore, for a better understanding of their microbial diversity and ecological adaptations (UV radiation and salinity range) we are sorting marine and high-altitude aquatic systems, with samples from Antofagasta coast and Chilean Altiplano (Salar de Huasco and Salar de Tara).We are optimizing a cell sorting method using a BD FACSJazz cytometer from frozen samples of different salinities suitable of being processes for genome sequencing and visualized with a confocal microscopy. Microbial communities have been selected depending on their size (<30µm) and fluorescence (Pigment fluorescence, SybrGreen, Propidium Iodide) trying different preservation methods: direct samples without any fixative and flash frozen in liquid nitrogen samples previously fixed with glutaraldehyde, GlyTE (glycerol-TE) or DMSO. We use glutaraldehyde as a control, since it is favorable both to separate well-defined frozen communities with the flow cytometer, as well as for confocal microscope visualization, however, less optimal for high throughput sequencing than DMSO or GlyTE. Using DMSO we have obtained differentiated communities with the flow cytometer, but cell degradation observed with the confocal microscope, very evident in autotrophs. In contrast, using GlyTE we have less defined communities, however better performance in the confocal microscope. The optimization of this method is especially useful to study picoeukaryotes communities coming from frozen samples with particular physical-chemical conditions such high salinity concentrations (~50psu).

FONDECYT INICIACIÓN 11170748 (CONICYT)

236 Genomic analysis of hydrocarbon-degrading and halotolerant Acinetobacter radioresistens DD78: An attractive candidate for saline soil bioremediation

Análisis genómico de degradación de hidrocarburos y halotolerancia en Acinetobacter radioresistens DD78: Un candidato atractivo para la biorremediación de suelos salinos

Constanza C. Macaya1, Roberto E. Durán1, Valentina Méndez1, Patricia Aguila2, Francisco Sàlva-Serra3, Edward R.B. Moore 3, Constanza Cárdenas4, Michael Seeger1. (1) Departamento de Química, Departamento de Química, Universidad Técnica Federico Santa María (2) Escuela de Tecnología Médica, Laboratorio de Microbiología, Universidad Austral de Chile (3) Sahlgrenska Academy, University of Gothemburg, University of Gothemburg (4) Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso

Bioremediation is an efficient, low cost and ecological technology for decontamination. Bioremediation processes based on hydrocarbon-degrading bacteria may be limited by salinity and low hydrocarbons bioavailability on the polluted matrix. Halotolerant bacteria and biosurfactant application improves bioremediation processes and hydrocarbon bioavailability respectively. The aims of this study were identifying hydrocarbons-degrading pathways and stress proteins in Acinetobacter radioresistens DD78, and the determination of its halotolerance. Genome sequencing was performed using PacBio RSII platform. Reads were assembled by HGAP, v3.0. Annotation was performed using Prokka, RAST and NCBI PGAP, v4.6. Geneswere identified by BLAST, using Uniprot-KB/Swiss-Prot database. Halotolerant assays were performed using R2A medium with 0-14% NaCl w/v. A. radioresistens DD78 grew in n-hexadecane and diesel, and produced the polymeric biosurfactant alasan. Genome of A. radioresistens DD78 is distributed in four replicons: one chromosome (3 Mb) and three plasmids (90, 81 and 70 kb). Catabolic genes, encoding an alkane monooxygenase and rubredoxin NAD(H) reductase/rubredoxin system, benzoate and anthranilate pathways were identified. Osmoprotectant betaine operon and transporters: osmo-dependent choline transporter, sodium/proline symporter and aspartate/alanine antiporter genes were identified. Three proteic alasan components were also identified. A. radioresistens DD78 was able to grow up to 4% NaCl and possess an emulsification index (E24) of 60%. DD78 strain was able to grow on diesel and n-hexadecane as sole carbon source under salinity conditions (3.5% w/v). Therefore, Acinetobacterradioresistens DD78 is an attractive halotolerant and biosurfactant-producing strain for bioremediation of hydrocarbon-polluted saline soils.

Beca CONICYT Doctorado Nacional 21181489/2019 (CM), Proyecto FONDECYT 1151174 (MS), Proyecto Anillo GAMBIO ACT172128 (MS, VM, RD), USM grants.

237 Study of metabolic capacities at genomic level for the systematic design of synthetic microbial consortia

Estudio de las capacidades metabólicas a nivel genómico para el diseño sistemático de consorcios microbianos sintéticos

Marianela Macchi1, Nelson E. Vega-Vela3,2, Irma S. Morelli4, Bibiana M. Coppotelli1. (1) Centro de Investigación y Desarrollo en Fermentaciones Industriales, CINDEFI (UNLP; CCT-La Plata, CONICET), La Plata, Argentina (2) Pontificia Universidad Javeriana, Bogotá, Colombia (3) Universidad de Bogotá Jorge Tadeo Lozano, Bogotá, Colombia (4) Comisión de Investigaciones Científicas de la Provincia de Buenos Aires, La Plata, Argentina.

Los consorcios microbianos sintéticos (CMS) suelen ser de baja complejidad y hacen que los mecanismos de interacción y regulación sean fácilmente investigados. Con las secuencias genómicas se pueden identificar reacciones metabólicas específicas y posibles metabolitos intercambiados. Estos datos resultan útiles para desentrañar las interacciones metabólicas e investigar conceptos ecológicos claves. Este trabajo tuvo como objetivo estudiar las capacidades metabólicas de 6 cepas bacterianas (Sphingobium sp. (AM), Klebsiella aerogenes (B), Pseudomonas sp. (T y Bc-h), Inquilinus limosus (I) y Burkholderia sp. (Bk)) aisladas de un consorcio natural degradador de hidrocarburos policíclicos aromáticos (PAH), empleando genómica funcional para proveer información en el diseño sistemático de un CMS. Se desarrolló un pipeline (fastp/Spades/prodigal/InterProScan/RASTserver/modelSeed) para el preprocesamiento, ensamblaje, predicción y anotación de las secuencias genómicas. El análisis in silico reveló que sólo una quinta parte de los genes totales codifican enzimas, transportadores y reguladores con funciones asignadas. Las cepas B y Bk mostraron una baja relación entre sí y con las otras cepas. B presentó un conjunto de enzimas únicas y no posee genes relacionados con las rutas de degradación de PAH; el agrupamiento por subsistemas reveló que Bk tiene mayor número de rutas metabólicas relacionadas a la degradación de PAH. AM es la cepa que menor número de enzimas comparte con el resto de las cepas aisladas del consorcio natural. Se predijeron las funciones metabólicas que desempeña cada miembro del consorcio y las interacciones dentro de la comunidad microbiana a escala genómica, proporcionando una base para la optimización del diseño de consorcios sintéticos.

PICT 2013-0103 AGENCIA NACIONAL DE PROMOCIÓN CIENTÍFICA Y TECNOLÓGICA

238 Rhizosphere actinobacteria of Lupinus from the Atacama Desert as important source of bioactive compounds

Actinobacterias de la rizósfera de Lupinus del desierto de Atacama como fuente importante de compuestos bioactivos

Francisca Andrea Marchant1,2, Jean Franco Castro1,2, Valeria Razmilic1,2, Diego Lagos1,2, Barbara Andrews1,2, Juan Asenjo1,2. (1) Centro de Biotecnología y Bioingeniería (CeBiB) (2) Departamento de Ingeniería Química, Biotecnología y Materiales, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile

The occurrence of extensive antibiotics resistant bacteria increases the need of finding novel bioactive compounds. Rhizosphere actinomycetes have been recognized as a promising biotechnological source of new bioactive compounds with plant growth-promoting and antimicrobial activities. The search for such new compounds has shiftedto underexplored environments to increase the possibility of discovery. In this study, a total of 139 actinobacteria were isolated from rhizosphere of Lupino (Lupinus oreophilus) of the Atacama Desert, a unique and extreme environment located in the north of Chile. They were characterized by bioassays, molecular techniques and enzymatic tests. Of the total, 86 were subjected to antimicrobial tests against a set of bacterial and fungal pathogens, and to detection of biosynthetic genes of specialised metabolites (PKS-I, PKS-II, NRPS and AHBA) by PCR. Sixty-nine percent of the isolates have shown significant antimicrobial activities against at least one of the tested indicator microorganisms. Strains were classified as belonging to theStreptomyces and Micromonospora genera, through morphological and 16S rRNA phylogenetic analysis. BOX-PCR genomic fingerprints revealed genetic variations among the isolates. Furthermore, the production of industrially important hydrolytic enzymes such as cellulase, protease, amylase and chitinase were observed. This study revealed that L. oreophilus is a rich source of actinobacteria with promising antimicrobial and enzymatic activities. Key words: actinobacteria; rhizosphere; antibacterial; phytopathogenic; hydrolytic enzyme.

We thank the Basal programme of CONICYT for funding the Centre for Biotechnology and Bioegineering (CeBiB, Project FB0001) and Beca CONICYT DOCTORADO NACIONAL scholarship 2017/21171090.

239 Genome-resolved metagenomics reveal co-occurrence and metabolic patterns of Cuniculiplasma and Micrarchaeota within a terrestrial hot-spring

Estudio metagenómico a nivel de genomas individuales revela la co-ocurrencia y patrones metabólicos de Cuniculiplasma y Micrarchaeota en una fuente termal terrestre

Roberto Marín-Paredes1, Yunuen Tapia-Torres1, Esperanza Martínez-Romero2, Luis Eduardo Servín-Garcidueñas1. (1) Laboratorio de Microbiómica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México (2) Laboratorio de Microbiología Ambiental y Simbiótica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (Sponsored by Universidad Nacional Autónoma De México)

El Eje Volcánico Transmexicano alberga al campo geotérmico de Los Azufres en el Estado de Michoacán, México. Los Azufres presentan manifestaciones termales con comunidades microbianas poco analizadas. En esta investigación se secuenció y analizó un metagenoma de sedimentos termales de Los Azufres que presentaban una temperatura de 73.4 °C y un pH de 3 durante la colecta. A partir de análisis bioinformáticos se lograron recuperar genomas consenso de poblaciones de arqueas pertenecientes al orden Thermoplasmatales y al filo Micrarchaeota. En particular se obtuvo el genoma de la arquea thermoplasmatal Candidatus Cuniculiplasma sp. AZ01 integrado por 277 contigs que contienen 1,858,996 pb, con una N50 de 18,461 pb, una cobertura de 346X, y un contenido de GC de 37.3%. Los genes ribosomales 16S rRNA de Ca. Cuniculiplasma sp. AZ01 y Cuniculiplasma divulgatum PM4 presentan 100% de identidad. Comparaciones genómicas de Ca. Cuniculiplasma sp. AZ01 y Cuniculiplasma divulgatum PM4 revelaron genomas conservados que presentan valores de ANI y DDH de 99.12% y 91.50% respectivamente, lo que indica que pertenecen a la misma especie. A partir del metagenoma, también se recuperó el genoma de la micrarchaeota Candidatus Micrarchaeum sp. AZ1, en cinco contigs que contienen 980,507 pb, con una N50 de 313,950 pb, una cobertura de 146X, y un contenido de GC de 45.8%. El genoma de Ca. Micrarchaeum sp. AZ1 es reducido y carece de vías metabólicas esenciales, incluidas las relacionadas con la síntesis de nucleótidos. Este metagenoma permitirá comprender mejor las posibles interacciones metabólicas entre arqueas Thermoplasmatales y Micrarchaeota.

Esta investigación recibió un apoyo financiero de parte del Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT IA210617) de la Universidad Nacional Autónoma de México.

240 Genomic diversity and metabolic versatility of Sulfolobales archaea from Mexican hot-springs

Diversidad genómica y versatilidad metabólica de arqueasSulfolobales de fuentes termales de México

Roberto Marín-Paredes1, Yunuen Tapia-Torres1, Esperanza Martínez-Romero2, Luis Eduardo Servín-Garcidueñas1. (1) Laboratorio de Microbiómica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México (2) Laboratorio de Microbiología Ambiental y Simbiótica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (Sponsored by Universidad Nacional Autónoma De México)

Archaea from the order Sulfolobales are thermoacidophiles commonly found in volcanic environments. Here we report the metagenome of a sediment sample collected from a fumarole (88.5°C, pH 2.8) at Los Azufres volcanic complex in Mexico. The 11,295,088 bp metagenome has 1,726 contigs, a N50 of 17,474 bp, and contains four Sulfolobales 16S ribosomal RNA genes. One of the 16S rRNA genes (1,498 bp) was identical to the corresponding gene of ‘Candidatus Aramenus sulfurataquae’ which represents a candidate genus first identified by a metagenomic survey from a mud hot-spring (65 °C, pH 3.6) also at Los Azufres. Genome assemblies revealed a second genome for ‘Ca. Aramenus sulfurataquae’ that contains 381 contigs (1,683,830 bp), with 98X coverage, a N50 of 11,028 bp, and 47.8% G+C content. Genome comparisons between the two assemblies of ‘Ca. Aramenus sulfurataquae’ revealed a DDH estimate of 81.70% indicating that there exist at least two distinct populations of ‘Ca. Aramenus sulfurataquae’ inhabiting at Los Azufres. Based on the genetic potential of ‘Ca. Aramenus sulfurataquae’ we predict it is a metabolically versatile archaeon that is able to ferment some sugars and peptides, and capable to use carbon dioxide as a source of carbon. Genes involved in nitrate assimilatory reduction were found as well as ammonium transporters. Transporters for phosphate, sulfate, amino acids, peptides, sugars, and heavy metals (Cr, As, Hg, Cd) were also predicted. Other detected Sulfolobales in the metagenome were related to Acidianus and Saccharolobus genera. The recovered metagenomic sequences will be useful for comparative analyses.

Esta investigación recibió un apoyo financiero de parte del Programa de Apoyo a Proyectos de Investigación e Innovación Tecnológica (PAPIIT IA210617) de la Universidad Nacional Autónoma de México.

241 Effect of salinity on the dynamics and diversity ofMicrocystis aeruginosa complex

Efecto de la salinidad sobre la dinámica y diversidad del complejo Microcystis aeruginosa

Gabriela Martínez1, Angel Segura2, Carla Kruk3,4, Claudia Piccini1. (1) Departamento de Microbiología, MEC, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE) (2) PDU Modelización y Análisis de Recursos Naturales, CURE-UdelaR (3) IECA, Sección Limnología, Facultad de Ciencias, UdelaR (4) PDU Ecología Funcional de Sistemas Acuáticos, CURE-UdelaR

Se ha descrito que la salinidad afecta negativamente el crecimiento de especies del complejo Microcystisaeruginosa (CMA), limitando su crecimiento. Si bien se han registrado floraciones en estuarios, se desconoce su viabilidad y toxicidad en dichas condiciones. En este trabajo se evaluó el efecto de la salinidad sobre organismos del CMA, combinando estudios de campo en un gradiente ambiental agua dulce-agua marina con experimentos de laboratorio sometiendo comunidades naturales del CMA a diferentes salinidades (5, 10 y 25).En cada aproximación se evaluó la abundancia (qPCR de genes mcy) y diversidad de organismos tóxicos (HRMA y CART) del CMA, así como la concentración de microcistinas. En las muestras de campo se observó una disminución de la abundancia y riqueza de organismos tóxicos en sitios con mayor salinidad, identificándose ecotipos característicos de salinidades estuarinas (25). Similarmente, los experimentos mostraron cambios en la estructura comunitaria del CMA a salinidad 25, observándose menos riqueza en comparación con la comunidad de agua dulce. Luego de 7 días, se detectó inhibición de la síntesis de microcistinas únicamente en el tratamiento con salinidad 25. Estos hallazgos sugieren que aunque los organismos del CMA pueden sobrevivir al estrés salino en rangos estuarinos (5-25), la producción de toxinas se ve afectada según el grado de estrés. Por lo tanto, cuando el CMA es transportado de sistemas dulceacuícolas a sistemas estuarinos-marinos se seleccionarían aquellos genotipos tóxicos capaces de soportar el estrés osmótico, mientras que la concentración de salinidad local modularía la producción de toxinas.

242 Bacterial Bioaerosols at Yokohama and Toyama in Japan

Bioaerosoles bacterianos en Yokohama y Toyama, Japón

Fumito Maruyama1, So Fujiyoshi1, Daisuke Tanaka2. (1) BIOREN, Universidad La Frontera (2) University of Toyama (Sponsored by SATREPS And KAKENHI)

Airborne microbes are ubiquitous in the atmosphere and play an important role in human health, agriculture, cloud formation, global climate, and atmospheric dynamics. The aim of this study was to get knowledge of bioaerosol characteristics between various particle matter (PM) fractions or between different locations. Air sampleswere collected during 2016, at a suburban site and an urban site in Japan. Coarse particles (suspended particulate matter- PM2.5) and fine particles (PM2.5) were collected using slit-jet air samplers. In addition,we sampled using eight-stage Andersen samplers. PM mass, inorganic ions, organic and elemental carbon, and elements were measured. Airborne bacterial abundance and community structure were determined by 16S rRNA gene-targeted quantitative PCR and amplicon sequencing, respectively. Air mass backward trajectory was analyzed. The PM mass concentration, chemical composition, bacterial abundance and community structure differed between urban and suburban sites and across aerosol size fractions. From the network analysis, both coarse and fine particle samples showed the locality in biotic- abiotic interaction. Interestingly, we observed that Legionella spp., the causal agents of legionellosis and Pontiac fever in humans, were mainly detected in >2.1 μm coarse particles. Our findings indicate that a complex set of environmental factors, including changing atmospheric conditions, are related to the composition of bacterial communities in urban and suburban site environments. The results of this study provide a foundation for understanding the interaction mechanisms of environmental factors with bioaerosols and the influence of bioaerosols on human health.

This work was supported by the KAKENHI (Grant Number 17K00579, awarded to DT), a research grant from the Toyama First Bank Scholarship Foundation to DT, and JST-JICA, SATREPS to FM.

243 The dose of Bacillus velezensis Bs006 influences the response to vascular wilt and affects the microbial functional groups associated with the rhizosphere of tomato seedlings (Solanum lycopersicum)

La dosis de Bacillus velezensis Bs006 influye en la respuesta al marchitamiento vascular y afecta los grupos funcionales microbianos asociados a la rizósfera de plántulas de tomate (Solanum lycopersicum)

Julián Esteban Másmela Mendoza1, Carlos Andrés Moreno Velandia2. (1) Universidad de Antioquia (UdeA), Grupo de Investigación Biotransformación. Calle 67 #53 - 108, Medellín, Antioquia, Colombia. [email protected] (2) Corporación colombiana de Investigación agropecuaria-AGROSAVIA, Centro de Investigación Tibaitatá. Kilómetro 14-Vía Mosquera, Cundinamarca, [email protected]

El objetivo del estudio fue evaluar el efecto de la dosis de endosporas (107 y 109/ml) y sobrenadantes (1%, 10% v/v) de la cepa Bacillus velezensis Bs006 en la respuesta al marchitamiento vascular de plántulas de tomate y evaluar el impacto de los tratamientos sobre los grupos funcionales microbianos de la rizósfera. Los tratamientos con sobrenadantes al 1% y con 107 endosporas/ml tuvieron una eficacia del 86,3±8,5% y del 64,65±12,9% en el control del marchitamiento vascular causado por Fusarium oxysporum f.sp. lycopersici Fol59 en plántulas de tomate, reduciendo los porcentajes de incidencia y los valores de severidad. Por el contrario, la aplicación al 10% de sobrenadante y 109 endosporas/ml registraron una eficacia menor del 48,6±7,74% y 59,4±6% y los tratamientos aumentaron la severidad de la enfermedad [Índice= 3,98±0,5 (escala de 1 a 5)]. La aplicación de concentraciones altas de Bs006 disminuye la abundancia de bacterias solubilizadoras de fósforo (BSF) y fijadoras de nitrógeno (BFN) (BSF=4,8±1,1 x105 UFC/g de suelo, BFN=6,8±2,9 x 104 NMP/g de suelo), en comparación a las plantas control no inoculadas (BSF=1,04±3,7 x106 UFC/g, BFN= 2,8x106 NMP/g). La respuesta metabólica promedio (RMP) en el uso de fuentes de C de la comunidad microbiana fue más alta en la rizósfera de plantas inoculadas con 10% y 109 endosporas/ml (RPM= 1,97±0,51) en comparación al tratamiento control (RPM=1,32±0,67), mientras que la diversidad funcional (Shannon=1,47±0,02) fue similar. Las dosis aplicadas de un biocontrolador pueden afectar los grupos funcionales cultivables de la rizósfera, los cuales cumplen funciones importantes en la nutrición de las plantas.

El proyecto es financiado por la Corporación Colombiana de Investigación Agropecuaria-AGROSAVIA-Sede Tibatitatá, Mosquera, Colombia.

244 Potential distribution and fundamental niche of Moniliophthora spp in cocoa crops of America and Africa

Distribución potencial y nicho fundamental de Moniliophthora spp en cultivos de cacao de América y África

Julián Esteban Másmela-Mendoza1. (1) Universidad de Antioquia (UdeA), Grupo de Investigación Biotransformación. Calle 67 #53 - 108, Medellín, Antioquia, Colombia. Biólogo. [email protected] (código https://orcid.org/0000-0002-6019-1449).

El objetivo del estudio fue analizar la distribución potencial y el nicho fundamental deMoniliophthora roreri (Mr) y M. perniciosa (Mp). Los registros de ocurrencia fueron obtenidos de una revisión bibliográfica, y se utilizaron variables bioclimáticas (BIO) como predictores en el modelo de nicho de máxima entropía (MaxEnt) y para su visualización en Niche Analyst 3.0. La capacidad de predicción del modelo de distribución de Mr (AUC=0.868+-0.0139) y Mp (AUC: 0.820+-0.017) fue buena. Las zonas donde se registró mayor probabilidad (pr) de ocurrencia de Mr (pr=0,7-1) fueron Esmeraldas y Los Ríos, Ecuador, zonas costeras de Costa Rica, Santander y Antioquia de Colombia. Las variables que más influyen en la distribución (AUC= 0,86) deMr son las precipitaciones promedio del trimestre del año más caluroso y la precipitación del mes más húmedo. Las condiciones relacionadas con la temperatura (temperatura mínima del mes más frío y rango diurno medio) fueron más importantes (AUC= 0,81) en el modelo de Mp. La transferencia de los modelos evidenció el potencial de invasión de Mr y Mp en los cultivos de cacao en África. El nicho fundamental de los patógenos y el cacao presentó valores de similitud medios (Jaccard= 0,5-0,7), mientras que el nicho de las especies de hongos mostró una baja similitud (0,3-0,34) . La baja similitud de los nichos de los patógenos podría ser explicada desde la teoría de la exclusión competitiva y se relaciona con un proceso de partición del nicho.

Este trabajo investigativo fue derivado de un proyecto de aula del curso semestral de modelamiento denichos ecológicos de la maestría en Biología, Posgrado de la Universidad de Antioquia, Medellín, Colombia.

245 Heavy metal tolerant extremophilic microbial consortia: a new hope

Consorcios microbianos extremófilos tolerantes a metales pesados: Una nueva esperanza

Francisco L. Massello1, Edgardo Donati1. (1) CINDEFI, Facultad de Ciencias Exactas, Universidad Nacional de La Plata

La contaminación por metales pesados representa un riesgo ambiental a nivel global dada su toxicidad y la imposibilidad de degradación. Los microorganismos de las comunidades afectadas poseen mecanismos de resistencia que les permiten sobrevivir en dichas condiciones. En particular, los microorganismos de ambientes extremos poseen mecanismos de poli-resistencia que les confieren gran adaptabilidad. Por esta razón, resulta interesante el estudio de comunidades, consorcios y microorganismos extremófilos bajo estrés metálico; no sólo para analizar el efecto en la composición filogenética, lo que podría utilizarse para la detección temprana y el monitoreo, sino también para obtener consorcios o microorganismos de utilidad en procesos de biorremediación y biolixiviación. En este trabajo realizamos enriquecimientos en metabolismos de interés biotecnológico (azufre/hierro oxidante, organoheterótrofo y anaeróbico) a partir de dos muestras ambientales de la región volcánica Caviahue-Copahue (Neuquén, Argentina), los adaptamos a altas concentraciones de metales pesados (Cd, Cu, Co, Ni y Zn) y estudiamos su composición a partir de la secuenciación del gen 16S ARNr. Para ello, utilizamos el nuevo concepto de variantes de secuencias de amplicones (ASV). Reportamos tolerancias tan elevadas como 400 mM. Los consorcios pudieron agruparse de acuerdo con su metabolismo más allá de la presión metálica, lo que sugiere versatilidad. Los géneros tolerantes más abundantes fueron Acidithiobacillus, Acidiphilium, Alicyclobacillus, Sulfobacillus y Ferroplasma, en los consorcios acidofílicos; Lysinibacillus, Paenibacillus y Bacillus en los organoheterotróficos; y Tizzerella y Clostridium en los anaeróbicos. La versatilidad y gran tolerancia de los consorcios obtenidos los vuelven de gran interés dado su potencial uso biotecnológico.

ANPCyT, PICT-2016-2535 y PICT-2015-0463

246 Multiresistant Escherichia coli : a way to export resistances

Escherichia coli multiresistente: una vía para exportar resistencias

Mirella Massonetto1, José Augusto Souza3,2, Vanessa Costa Andrade4, Roberta Merguizo5, Bruna Del Busso Zampieri6, Ana Júlia Fernandes Cardoso De Oliveira6,1. (1) Instituto de Biociências- laboratório Micromar, Campus de Rio Claro, Universidade Estadual Paulista-UNESP Brasil (2) Institute of Biosciences, Campus do Litoral Paulista- São Vicente, São Paulo State Univiversity- UNESP- (3) Institute of Biosciences, São Vicente, São Paulo State Univiversity- UNESP- (4) Institute of Biosciences, Rio Claro, UNESP- São Paulo State University (5) Instituto de Biociências- laboratório Micromar, Campus do Litoral Paulista- São Vicente, Universidade Estadual Paulista-UNESP Brasil (6) Institute of Biosciences, Campus Rio Claro, UNESP- São Paulo State University

In Brazil the occupation of coasts areas started without planning, causing environmental impact in these areas. In São Paulo state (Brazil), CETESB is responsible for monitoring coastal areas, including beaches. This monitoring does not consider adjacent areas or drugs, (e.g antibiotics), in the marine environment. In this context, Santos does not have environmental monitoring programat the six drainage canals. This study aimed to evaluate the resistances of Escherichia coliisolated, from water and sediment samples, at three points in each canal for three months. The sampling was carried out at low tide in order to evaluate the contents of the channels. Was performed Membrane Filter Technique using mTEC Agar. Positive strains, tested by solution of urea and red phenol (2%), were isolate in selective medium. Susceptibility was performing by disc-difusion, according to BrCAST guidelines, for the following antibiotics :amoxicillin, amoxicillin+ clavulanate, ampicillin, levofloxacin, gentamicin and amikacin.All the strains (n=36) were resistant to all antibiotics. According to the present results, water samples showed densities higher than CONAMA and CETESB standards. The sediment is not included in the legislation, evidencing negligence of the authorities. It is worrisome, since the waters debouch on the beach interfering in the environment quality and being a serious risk to bathers. Other point is that high resistance can work as resistomes in the environment.. In this context, the lack of a specific legislation, represents a serious risk to the environment and the public health, once that affect local microbiota and increases pathogenic and resistant bacteria. CAPES

247 The neglected coastal areas and the problem from multiresistent microorganisms

Las áreas costeras descuidadas y el problema de microorganismos multiresistentes

Mirella Massonetto1, José Augusto Souza2, Vanessa Costa Andrade1, Roberta Merguizzo3, Bruna Del Busso Zampieri4, Ana Júlia Fernandes Cardoso De Oliveira3,1. (1) Institute of Biosciences- Micromar Laboratory, Campus Rio Claro, Universidade Estadual Paulista-UNESP Brasil (2) Institute of Biosciences - Micromar Laboratory, Campus Litoral Paulista- São Vicente, São Paulo State University (3) Institute of Biosciences - Micromar Laboratory, Campus do Litoral Paulista- São Vicente, São Paulo State University (4) Institute of Biosciences - Micromar Laboratory, Campus Rio Claro, São Paulo State University

Worldwide, coastal areas include part of population suffering many environmental impacts, such as the discharge of sewage without treatment. The input of untreated sewage in coastal areas may lead to the selection of resistant microorganisms that work as a resistome. Although the beaches receive more attention, because they are very important for the tourist, adjacent areas are neglected acting as a potential polluting source. The present study aimed monitoring Enterococcus sp presence and resistance to antibiotics at six drainage canals in Santos municipality during three months. Water and sediment samples were collected and analyzed by Membrane Filter Technique using mEnterococcus Agar. According to BrCAST guidelines the positive strains were confirmed by Enterococosel and isolated in Nutrient agar to perform the antibiogram teste by Disc-Difusion Method. From each kind of sample was isolated 36 strains in each campaign, that was tested to ampicillin, erythromycin, tetracycline, ciprofloxacin and levofloxacin. All the isolates (36) tested were considered multiresistant to all the five antibiotics. The antibiogram results revealed a kind of consumption profile about antibiotics and howit influences on the selection of resistant genes, when does not exist a sewage treatment. Enterococcus spp is known to be multiresistant to many substances and to be responsible for several cases of hospital infection, showing how important is to monitoring and treat the sewage and to rethink our antibiotics consumption.

CAPES

248 Optimization of use and traceability of probiotic strain Pseudoalteromonas sp. label with Green Fluorescent for use with marine organism

Optimización del uso y trazabilidad de la cepa probiótica Pseudoalteromonas sp. transformada con la proteína verde fluorescente (GFP) para estudios de aplicación en organismos marinos

M. Teresa Mata1, Henry Cameron1, Carlos E. Riquelme1. (1) Centro de Bioinnovación, Departamento de Biotecnología, Facultad de Ciencias del mar y recursos biológicos, Universidad de Antofagasta

El uso de probióticos en acuicultura es actualmente una alternativa al empleo de antibióticos y otros químicos perjudiciales para los organismos y el ecosistema a corto y largo plazo. En este aspecto, la búsqueda de nuevos microrganismos con capacidad probiótica es un campo con amplia proyección. La cepa SLP1 de la bacteria Pseudoalteromonas sp., de reciente descubrimiento, ha demostrado tener buenas cualidades como probiótico generando un aumento de la viabilidad de cultivos larvales de Seriala Lalandi. Para poder hacer un buen seguimiento de la ruta de inclusión en los sistemas y la actividad de dicho probiótico, el marcaje mediante la Green Fluorescent Protein (GFP) es una excelente herramienta que puede permitir el seguimiento de dicho microorganismo. En este trabajo, se consiguió transformar la cepa SLP1 con un vector que contenía el gen para GFP con resistencia para Gentamicina. Los resultados de las pruebas del cultivo indican que existen un mejor crecimiento del transformante en medio Zobell y los resultados de estabilidad del fenotipo, en diferentes medios de cultivo mediante citometría de flujo, demostraron que se requiere un proceso de activación en medio nutritivo para que se exprese el fenotipo. Por otro lado, los resultados de visualización bajo microscopia confocal demostraron que las bacterias pueden ser satisfactoriamente detectadas en conjunto con microalgas y dentro de organismos superiores como larvas de peces, así como en rotíferos, los cuales se emplean como vector de inclusión de los probióticos en los cultivos larvales.

Proyecto FONDEF DE10I1050 y FONDEQUIP EQM120137

249 Two copies of Bradyrhizobium sacchari nifH have different relative expression levels in different nitrogen fixation conditions

Dos copias del gen nifH de Bradyrhizobium sacchari presentan niveles diferenciales de expresión relativa en diferentes condiciones de fijación de nitrógeno

Gustavo Feitosa Matos1, Cleudison Gabriel Nascimento Silva2, Jean Luiz Simões-Araújo3, José Ivo Baldani3, Luc Felicianus Marie Rouws3. (1) Phytothecnics, Agronomic engineering, Federal Rural University of Rio de Janeiro (2) Federal University of Lavras (3) EMBRAPA AGROBIOLOGIA

Bradyrhizobium sacchari was isolated from sugarcane roots and found to be a legume-symbiont with ability to express nitrogenase activityin vitro. Genome sequencing of B. sacchari BR10280T revealed the presence of 43 genes involved with nitrogen fixation (NF), including duplicates of the nifHDK nitrogenase genes. Although duplication of nif-genes has been observed in other Bradyrhizobium species, phylogenetic analyzes of the nifH1 and nifH2 genes showed 15% nucleotide divergence, which is uncommon in this genus. This study aimed to verify if there are differences in expression betweennifH 1 and nifH2 genes of strain BR10280T grown in different conditions: 1)in vitro NF (semi-solid JMV medium), 2) symbiotic NF (BR10280T living inside active Vigna unguiculata nodules) and, 3) in vitro with NF suppressed (shaking in rich liquid medium). RT-qPCR (using random hexamers) was performed with RNA obtained from BR10280T cells growing in the described conditions. Transcript abundance was determined by relative quantification in relation to transcripts of two housekeeping genes. Acetylene reduction assay was performed to evaluate nitrogenase activity at time of sampling. The results showed that transcripts of nifH2 were 10 times more abundant than nifH1 in vitro NF cells. In contrast, nifH1 transcript levels were slightly higher than nifH2 in V. unguiculata nodules. Expression of both copies was strongly repressed in rich liquid medium, as expected. These results suggest that each nifH copy in strain BR10280T has a differentiated physiological function, which may have permitted adaptation of the strain to fix nitrogen in diverse environments.

National Council for Scientific and Technological Development

250 Inner and outer microbiota associated to young red sea urchin Loxechinus albus farming under controlled conditions

Microbiota interior y exterior asociada al cultivo de ejemplares jóvenes de erizo rojo Loxechinus albus bajo condiciones controladas

Daniel A Medina1, Rudy Suarez1,2,3, Florencia Navarrete4, Marcos Godoy1,2,5. (1) Laboratorio de Biotecnología Aplicada, Facultad de Medicina Veterinaria - Sede De la Patagonia, Puerto Montt, Chile, Universidad San Sebastián (2) Centro de Investigaciones Biológicas Aplicadas, Puerto Montt, Chile. (3) Magíster en Acuicultura, Antofagasta, Chile., Universidad Católica del Norte (4) Centro Acuícola Pesquero de Investigación Aplicada - CAPIA, Puerto Montt, Chile, Universidad Santo Tomás (5) Doctorado Programa Cooperativo Universidad de Chile, Universidad Católica del Norte, Antofagasta, Chile

Loxechinus albus is a shallow water sea urchin, and its distribution is related with the cold water currents of the southern hemisphere. Chile is the more important exporter, with a production around 30.000 tons per year. Diseases are an important cause of mortality of sea urchin. Bald sea urchin disease affects several species in the northern hemisphere, turning the surfaces green and causing lack of spines. Two pathogens are the main responsible for the disease, Listonella anguillarum and Aeromonas salmonicida. However, little is known about what pathogens impairs L. albus health.The importance of bacterial communities, also called microbiota, in sea urchin health has been recently started to be explored. It has been suggested that urchin gut microbiota are responsible for differences in algal digestion and synthesis of essential long-chain fatty acids. In this study, we collected young specimens of the red sea urchin L. albus to characterize the body surface and inner bacterial communities using 16S rDNA gene sequencing. Also, we analyzed specimens with surface lesions similar to those produced by bald sea disease. Alpha diversity based on Chao1 and Shannon index showed that there were statistically significant differences between inner and outer microbiota, as well as between injured and healthy surfaces. Taxonomic abundance showed diverse bacterial communities, belonging mainly to the phylum Proteobacteria, following by Bacteroidetes, Fusobacteria and Firmicutes. Besides, predictive metagenomics shows that the bacterial functionality is associated to metabolic pathways related with the use of a large variety of energy sources.

This work was Funded by CORFO-15PTEC47385-(PE0106) and supported by Universidad San Sebastián.

251 Characterization of the skin microbiota of a relict population of Agalychnis annae from Costa Rica and its possible effect on survival against chytridiomycosis

Caracterización de la microbiota de la piel de una población relicta de Agalychnis annae de Costa Rica y su posible efecto en la supervivencia contra la quitridiomicosis

Bradd Mendoza1, Juan Abarca2, Catalina Murillo3, Ibrahim Zuñiga3, Fiorella Fiatt3, Steven Whitfield4, Adrián Pinto3,1,5. (1) Centro de Investigación en Estructuras Microscópicas, Universidad de Costa Rica (2) Laboratorio de Recursos Naturales y Vida Silvestre, Universidad Nacional (3) Departamento de Bioquímica, Escuela de Medicina, Universidad de Costa Rica (4) Conservation and Research Department, Zoo Miami (5) Centro de Investigación en Biología Celular y Molecular, Universidad de Costa Rica

Chytridiomycosis caused by Batrachochytrium dendrobatidis (BD) is associated with amphibian decline throughout the world and disease severity could be linked to the pathogen’s genotype. However, some populations did not experience declines or have recovered, and therefore are considered relict. In this study, we examine a relict population of Agalychnis annae from the central valley of Costa Rica. Our aims were to characterize the skin microbiota of A. annae by 16S rRNA amplicon sequencing and to culture and test the inhibition activity of skin bacteria against four Costa Rican BD strains previously genotyped by multilocus sequence typing. The microbial community analysis shows that Proteobacteria is the most abundant phylum, followed by Actinobacteria and Bacteroidetes, with these three phyla representing 97% of the total bacterial taxa. Isolated bacteria from the genera Serratia, Pseudomonas and Chryseobacterium can inhibit growth of some BD strains, but none of these bacteria could inhibit all four of them. Finally, we found that Costa Rican BD strains belong to the global hyper-virulent group GPL2 described in previous studies. Taken together, these results suggest that it is highly relevant to understand the local dynamics of skin bacteria and circulating BD pathogens to design and implement strategies to mitigate Chytridiomycosis in the Tropical Regions.

Investigaciones ecológicas con una población de ranas costarricenses sobrevivientes al declive poblacional para desarrollar estrategias útiles en la conservación de anfibios. Número de proyecto: B7A46 inscrito en la Vicerrectoría de investigación Universidad de Costa Rica

252 Producción de compuestos de origen microbiano y conservación: ¿Por qué debemos hacer una valoración para preservar el hábitat microbiano?

Production of microbial bioactive compounds and conservation. Why we should assess the value of the preservation of microbial habitats?

Daniela Meneses1,2, Carmen Cruz1, Bárbara Ossandón1, Cristina Dorador1,2. (1) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta. (2) Centro de Biotecnología y Bioingeniería (CeBiB).

Los estudios realizados en el Norte de Chile, específicamente humedales y lagunas del Altiplano Chileno, han permitido determinar que estos sitios presentan una alta variabilidad temporal y espacial, con una gran diversidad microbiana. Las comunidades microbianas presentes en estos sitios se ven expuestas diariamente a condiciones extremas u hostiles para la vida tales como altas concentraciones salinas, amplia variación de temperatura, alta radiación UV y una alta concentración de metales o metaloides como As, Cu, Fe, Si, entre otros. Los microorganismos también son proveedores de servicios ecosistémicos, sin embargo se desconoce en detalle los alcances y características de estos servicios en ecosistemas altoandinos. Para este estudio se consideró la información existente de diversidad (aislados, secuencias ambientales del gen 16S rRNA) y función microbiana (genes funcionales) en los sistemas Salar de Huasco, Salar de Llamará y al sitio geotermal Quebrada del Zoquete.

Los resultados de este trabajo presentan a estos sitios poco estudiados como un hotspot de diversidad microbiana, quienes cumplen los servicios de regulación, soporte, provisión y cultural, lo cual permite tener un marco de referencia comparativo para la valorización ambiental de estos frágiles sistemas. Los aislados obtenidos producen unaalta variedad de compuestos con propiedades bioactivas. Grupos específicos están involucrados en el ciclaje de nutrientes y productividad primaria entre otros de acuerdo a la Evaluación de los Ecosistemas de Milenio (2005). Debido a la rápida degradación ambiental de ambientes como salares, es urgente relevar el rol de los microorganismos junto con su valorización ecosistémica.

Financiamiento: FONDECYT 1181773

253 Biodegradation of s10 diesel fuel and afff by bacillus subtilisand bacillus licheniformis isolated from Porto de Santos (sp)

Biodegradación de combustible diesel s10 y afff por bacillus subtilis y bacillus licheniformis aislados del Porto de Santos (sp)

Roberta Merguizo1, Vanessa Da Costa Andrade2, Bruna Del Busso Zampieri2, Mirella Massonetto2, José Augusto Souza1, Dejanira De Franceschi Angelis2, Ana Julia Fernandes Cardoso Oliveira1. (1) Micromar, Bioscience Institute, UNESP Litoral Paulista (2) Applied Microbiology Program, Bioscience Institute, UNESP Rio Claro

The number of accidents causing environmental damage has grown concomitantly with the development of the oil sector, leading to investment in fire and explosion protection measures in recent decades. The difficulty of fighting fires involving hydrocarbons with common compounds led to the use of special foams for fire control, the AFFF (Aqueous Film-Forming Foam). Bacterial bioremediation for petroleum derivatives is a strategy often adopted due to the low cost, there is at present no information on bacterial efficiency in the bioremediation of the AFFF co- contaminant. This study aimed to analyze the biodegradation of S10 diesel and AFFF by Bacillus subtilis and Bacillus licheniformis strains and by the consortium of two strains isolated from estuaries of Santos (SP). Bartha respirometric assays were performed with inoculum at 10% of selected strains, 5% diesel S10 and 6% AFFF. Coastal sediment was performed as negative control. The accumulated production was measured in micromol (μmol) throughout 120 days.

The strain with the best potential wasB. licheniformis. The highest CO2 production was 1.51E + 04 μmol with 72 days for respirometry with diesel, while the AFFF with the highest CO2 production was 8.41E + 03 with 52 days. The CO2 production in the S10 diesel test was higher than in the foam tests, this difference is due to the fact that heterotrophic bacteria have a greater ability to degrade PAH substances. The B. licheniformis strain has a higher bioremediation potential for both diesel and AFFF in relation to B. subtilis strain to the consortium.

CAPES

254 Seasonal changes of marine bacterial diversity along the particulate matter continuum in a temperate coastal ecosystem

Cambios estacionales en la diversidad microbiana marina presente a lo largo del contínuo de particulas marinas en un ecosistema costero templado

Mireia Mestre1, Josep M Gasol2, M Montserrat Sala2. (1) Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción (2) Biología y Oceanografía, CSIC, Instituto de Ciencias del Mar de Barcelona

The temporal dynamics of ocean prokaryotic community structure in the free-living fraction has been well studied, yet it does not take into account the heterogeneity of habitats present in particles of distinct size that are also colonized by prokaryotes. Using a serial filtration differentiating 6 size-fractions spanning from 0.2 to 200 µm, we sampled monthly during two years in a temperate oligotrophic coastal ecosystem (Blanes Bay Microbial Observatory, NW Mediterranean Sea) to describe the bacterial community structure in each particle-size range as it varies through the seasonal cycle. We observed that each size-fraction had specific bacterial communities, and that communities changed gradually with time, being the communities in smaller size-fractions the ones with lower changes through the year. Day length and surface-water temperature were the main drivers of bacterial community differentiation through the year, and communities presented two major assemblies, corresponding with the warm (from May to October) and cold (from November to April) periods. Warm and cold seasons were dominated by distinct taxa, and while some taxonomic groups, such as Synechococcus or Rhodobacterales, maintained the preference for small or large size fractions, respectively, during most of the year, others (such as SAR11 or Planctomycetes) varied their distribution into different fractions along time.Summing it up,our data indicate that the analysis of communities in the different size fractions should be incorporated in temporal surveys to obtain a more comprehensive view of the dynamics of planktonic bacterial communities over time and to better describe the diversity of the whole ecosystem.

255 The krill microbiome

El microbioma del krill

Mireia Mestre1, Juan Höfer2, Camila Fernandez1. (1) Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción (2) Escuela de Ciencias del Mar, Ciencias del Mar y Geografía , Pontificia Universidad Católica de Valparaíso

Animals are host of complex microbial communities, from all divisions of life, which are fundamental for their growth and development. In this context, zooplankters represent marine pelagic niches that microorganisms are able to colonize. The main objective of this project is to describe the microbial diversity and functioning of the microbiome associated with a key zooplankter in the Southern Ocean food webs: krill. Samples of krill (N=1300) and seawater (N=305) were taken during January and February of 2019 in areas offshore the Northern and Western Antarctic Peninsula. We collected two kinds of samples: samples to analyze Microbiome Diversity (MD samples) and samples to analyze Microbiome Function (MF samples). In MD samples, the 16S and 18S region of the rDNA was sequenced. In MF samples, all the functional genes (metaGenomes) present inside the guts of krill and seawater were sequenced. The target microorganisms were prokaryotes (bacteria and archaea) and small unicellular eukaryotes (including fungi). All raw genomic data was processed through specific bioinformatic pipelines.

FONDAP‐IDEAL (15150003); Fondecyt postdoctorado (3190369) “Connecting the zooplankton microbiome with ecosystem processes in the Southern Ocean”; Antarctic Sicence International Bursary (2019) “A detailed analysis of krill microbiome”, a bursary from Antarctic Science Ltd

256 Microbiological agriculture of the agroecological tomato: a new look of the soil and its impact on the productivity

Agricultura microbiológica del tomate agroecológico: una nueva mirada del suelo y su impacto en la productividad

Marcela Carvajal 1, Michael Seeger1, Alejandra Vergara1, Pamela Lienlaf2, Jorge Sanchez2, Alexis Velásquez1, Franco Jorquera3, Fernando Dorta3, Debora Estefania Meza4, Makarena Olivares1. (1) Química, Universidad Técnica Federico Santa María (2) Mavida (3) Universidad Técnica Federico Santa María (4) Universidad Andrés Bello

Actualmente, los agricultores de tomate de la región de Valparaíso están ampliando su foco de atención hacia nuevos tratamientos para el control de patógenos y mejoramientos de suelos cultivables. Entre los tratamientos eco-sustentables está la aplicación de diversas mezclas de abono en base a compost, bokashi, ácidos húmicos y otros, para el mejoramiento del suelo, así como también la aplicación de microorganismos benéficos que aportan al enriquecimiento del suelo, así como también al control biológico de plagas y enfermedades que afectan al cultivo del tomate.

El estudio tiene como objetivo evaluar parámetros físico-químicos y microbiológicos (identificación y cuantificación de microorganismos) durante el tiempo de cultivo en suelos tratados con compost, bokashi, Trichoderma spp. y un control en 8 predios de la región. Se estudiará el efecto en la calidad nutricional del tomate en relación a estos tratamiento orgánicos en presencia de los distintos tipos de manejo agrícola de cada productor.

Los resultados muestran que después de los 3 meses existe una tendencia en el aumento de ciertos grupos bacterianos como actinomycetes y azotobacter en predios con tratamientos convencionales y un aumento en el conteo fúngico de mesas tratadas con bokashi en predios con manejo eco-sustentable.

Algunas de las cepas identificadas, mediante secuenciación de región ITS, en los predios de uso agrícola de Limache y Quillota corresponden a Trichoderma asperellum, Trichoderma reesei, Trichodera harzianum. Esta iniciativa está financiada por el gobierno regional de Valparaíso FIC-R 2017. N°40004866

257 Effect of the application of static magnetic field, type pulse and continuous type, in the adhesion of biofilm in seawater pipes

Efecto de la aplicación de campo magnético estático tipo pulso y tipo continuo, en la adhesión del biofilm en tuberías de agua de mar

Carol Miranda1, Génesis Serrano1, Pablo Ferrada 2, Mauricio Escalona1, Victor Jimenez1, Alejandro Maureira1, Manuel Zapata1. (1) Biotecnologia, Ciencias del Mar y Recursos Biologicos, Universidad De Antofagasta (2) Centro de Desarrollo Energético Antofagasta, Ingeniería, Universidad De Antofagasta (Sponsored by Laboratorio De Biotecnología Algal Y Sustentabilidad)

En esta investigación se busca estudiar la formación del biofouling en las tuberías de transporte de agua de mar, desde un punto ecológico, sometiéndolo a perturbaciones con campos magnéticos estáticos (CME) tipo pulsoy tipo continuo (press), las cuales podrían afectar la formación del biofouling en las tuberías de transporte de agua de mar. Los parámetros físico-químicos (temperatura, pH, conductividad, oxígeno disuelto y salinidad) se midieron diariamente utilizando una sonda multiparametros. Se realizó primeramente la caracterización del CME utilizando el software Comsol Multiphysics, para conocer y dar forma a la perturbación. Para el muestreo de tuberías,se cuantificó la biomasa total adherida, recuento de bacterias totales, extracción y cuantificación de exopolisacáridos. Los resultados obtenidos en el tratamiento tipo pulso, estimulan la adhesión de biomasa en las tuberías, con una mayor concentración de bacterias totales en comparación con el control sin CME. A diferencia del tipo continuo, donde hubo una disminución en la adhesión de biomasa y en la concentración de bacterias totales en comparación al tratamiento pulso y la condición control. Se concluye que el tratamiento tipo pulso de CME estimula la proliferación de bacterias en la formación del biofilm y el tratamiento continuo produce el efecto contrario que es la disminución de proliferación de bacterias y formación de la biopelícula. El CME es una potencial herramienta biotecnológica, que puede ser utilizado como inhibidor o promotor del crecimiento, dependiendo de los requerimientos de la industria. Proyecto Programa Semillero de Investigación de la Universidad de Antofagasta

258 Compost application and phosphate solubilizing bacteria promote changes in the fungal community composition and increase sugarcane yield

La aplicación de compost y las bacterias solubilizadoras de fosfato promueven cambios en la composición de la comunidad de hongos y aumentan el rendimiento de la caña de azúcar

Antonio Marcos Miranda Silva1, Henrique Petry Feiler1, Ademir Durrer1, Gérman Andrés Estrada-Bonilla2, Rafael Otto1, Elke JBN Cardoso1. (1) Soil Science, Luiz de Queiroz College of Agriculture, University of São Paulo (2) Colombian Corporation for Agricultural Research, AGROSAVIA

Sustainable management systems have received increasing attention for crops with economic importance in Brazil, the largest world producer of sugarcane. We applied organic compost to the sugarcane crop in the field, in order to potentiate this practice and to decrease the use of phosphate soluble mineral fertilizers. The compost was prepared with sugar cane mill by-products (filter cake and ash), enriched with rock phosphate and inoculated or not with phosphate solubilizing bacteria (PSB). The experiment consisted of treatments with organic compost with different combinations of P and PSB, plus a control treatment that received only synthetic inputs (superphosphate). Twelve months after planting, soil samples (0-20 cm) were evaluated for the fungal soil community, which was sequenced (ITS region). Compost application, without enrichment (C) or enriched with phosphorite (C+P) increased the relative abundance (RA) of the genera Trichoderma, Chaetomium and Talaromyces and reduced the RA of the genus Solicoccozyma, but only in the treatments with PSB inoculation. C and C+P treatments showed significantly higher yield (153 and 147 Mg ha-1) than the control treatment (144 Mg ha-1). Thus, we demonstrated that in the presence of composted organic matter alone or when given compost plus rock phosphate and PSB, there was a great gain in sugarcane yield, reflecting a greater absorption of P. Therefore, we recommend this management in the future, because it encompasses a significant agricultural economy allied to an ecologically correct treatment and reuse of organic residues, of outstanding importance for the maintenance of the sanitary conditions in the world.

Brazilian National Council of Scientific and Technological Development (Conselho Nacional de Desenvolvimento Científico e Tecnológico-CNPq) and The São Paulo Research Foundation (Fundo de Amparo à Pesquisa do Estado de São Paulo-FAPESP) Project Number 2016/18944-3

259 Towards determining the microbial diversity associated to spheroidal particles in a travertine system in La Puna Argentina

Estudio de la diversidad microbiana asociada a partículas esferoidales en un sistema de travertínico-tufáceo en La Puna Argentina

Estela Cecilia Mlewski1, Agustin Mors1, Fernando Gomez1, Emmanuelle Gerard2, Ricardo Astini3. (1) Geomicrobiologia, Ciencias Exactas Fisicas y Naturales-UNC, Centro de Investigaciones en Ciencias de la Tierra (2) Genomic, Paris 7, Institut de Physique du Globe Paris (3) Analisis de Cuencas, Ciencias Exactas Fisicas y Naturales-UNC, Centro de Investigaciones en Ciencias de la Tierra

Termas Los Hornos (TLH, Puna-Argentina) is a hydrothermal system at 3500 masl where extreme environmental conditions yields an extensive microbialitic system. Both physical and chemical processes influence carbonate precipitation. However, the microorganisms found over all the system could also have important implications. This work focuses in the diversity of microorganisms associated to spheroidal mm-cm size particles found within shallow low-flow regime active travertine pools and their preserved biosignals. Bacterial and archaeal diversity was analyzed by 16S rDNA Illumina Miseq sequencing plus SEM and confocal microscopy observation of embedded samples. The carbonate microtextures were also analyzed. Our results show that Cyanobacteria was the most abundant phylum, followed by Proteobacteria (with Alphaproteobacteria as the most abundant order) and Bacteroidetes. Phyla like Verrucomicrobia, Spirochaetes and Acidobacteria were also observed but in much lower abundance. SEM and CSLM show diatoms and groups of Cyanobacteria. One of the most abundant Cyanobacteria observed belongs to Rivularia genus that is morphologically similar to a new species isolated from Laguna Negra (LN), a hypersaline lake at 4300 masl. Rivularia halophila and the consortia of microorganisms associated to their filaments was involved in the precipitation process of carbonates in the LN. Interestingly, in TLH, Rivularia-like filaments was observed in petrographic thin sections of the spheroidal particles. This observation suggests that specific lineages may influence calcium-carbonate precipitation and could provide clues to identify lineages that specifically leave biosignatures in fossil records.

• Proyecto PIP CONICET. Director de Proyecto: Dr. Fernando J. Gomez. • Proyecto de Cooperación Internacional CONICET-CNRS

260 First approach to the microbial diversity in the James Ross Archipelago, Antarctica

Primer acercamiento a la diversidad microbiana de lagos del archipiélago James Ross, Antártida

Guillermo Fernandez 1, Estela Cecilia Mlewski2, Eliana Soto Rueda2, Karina Lecomte2. (1) Geomicrobiologia, Ciencias Exactas Fisicas y Naturales-UNC, Centro de investigacion en Ciencias de la Tierra (2) Geomicrobiologia, Ciencias Exactas Fisicas y Naturales-UNC, Centro de Investigaciones en Ciencias de la Tierra

The Antarctic benthic areas that receive sufficient solar radiation are covered by microbial mats. For thousands of years these microorganisms were challenged to extreme conditions, such as low temperatures, freezing-thawing periods, high UV-irradiation, elevated salinity and low nutrient concentrations. In this context, many ofthem develop adaptations and in consequence potential microorganisms belonging to endogenous taxa and organisms not identified yet, can still be discovered. The terrestrial vegetation in the James Ross Archipelago is limitedto lichens and bryophytes, whereas microbial benthic mats are composed of algae and cyanobacteria. However, no studies of the microbial diversity -using high-throughput sequencing technologies as well as the analysis of mineral precipitation and fossil mats record in these lakes- have been conducted. For these reason, in a first step, we focused on the study of the bacterial diversity of three microbial mats corresponding to two lakes in James Ross Island and one in Vega Island. We used 16S rDNA amplicon secuencing by Illumina Miseq analysis. Preliminary results show that Proteobacteria was the most abundant phylum, in both island but differences were found in Bacteroidetes, Cyanobacteria and Actinobacteria phyla. These differences in abundance could be related to the physicochemical characteristic of the lakes like pH (8.5 to 10.2), the concentration of organic matter vs inorganic carbon content and trace metal concentration. This multidisciplinary study will contributes to a better understanding of Antarctic lake systems and can be used as a baseline dataset for further studies investigating the impact of climate changes in these pristine ecosystems.

supported by a bursary from Antarctic Science Ltd

261 Biofertilizers: native bacteria for exhausted horticultural soil restoration

Biofertilizantes: bacterias nativas para restauración de suelos fruti-hortícolas de uso intensivo

Andrea Micaela Monroy1, Silvana Beatriz Basack1, Diana Lía Vullo2,1. (1) Área Química, Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires, Argentina (2) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

La horticultura periurbana es una actividad con alto impacto en la calidad del suelo y su diversidad microbiana. Frecuentemente se recurre a un uso indiscriminado de fertilizantes y productos fitosanitarios para mejorar la productividad de los cultivos con un impacto negativo en el ambiente. Una manera de prevenir el deterioro del suelo es el desarrollo de inoculantes a base de bacterias nativas promotoras de crecimiento vegetal que mantienen y restauran la calidad del suelo de uso intensivo y optimizan el rendimiento del cultivo. El objetivo de este trabajo fue estudiar bacterias de vida libre y aisladas de suelos hortícolas contaminados con hidrocarburos y plaguicidas como potenciales componentes de bioinoculantes. Se evaluó la capacidad de Pseudomonas migulae S1-2, Sphingobium yanoikuyae SP-3 y Leucobacter aridicollis RP-7 para producir ácido indolacético (AIA) y solubilizar fosfato inmovilizado proveniente del mismo suelo del que fueron aisladas, sabiendo que no existen interacciones inhibitorias entre ellas. Se incubaron las bacterias en caldo Triptona bajo agitación a 32ºC. Al cabo de 6 días se cuantificó AIA en sobrenadantes de cultivo obteniendo 7,8; 3,7 y 3,5 ug AIA /ml en cepas de P.migulae S1-2, S.yanoikuyae SP-3 y L.aridicollis RP-7, respectivamente. Para el evaluar la solubilización de fosfato, se incubó en medio NBRIP con 5g de suelo fruti-hortícola por 14 días en agitación a 32ºC. Para P. migulae S1-2 se registró un aumento de 14 veces en la concentración de fósforo solubilizado. Estos resultados marcan el primer paso en el diseño de biofertilizantes para recuperación de suelos hortícolas degradados.

Este trabajo fue financiado por Universidad Nacional de General Sarmiento y CONICET.

262 Invasive capacity of the fungus Trichoderma harzianum in experimental fungal communities

Capacidad invasora del hongo Trichoderma harzianum en comunidades fúngicas experimentales

María Camila Morales1, Cecilia Muster1, Julieta Orlando1, Margarita Carú1. (1) Departamento de Ciencias Ecológicas, Facultad de Ciencia, Universidad De Chile

Las invasiones biológicas representan una amenaza para la biodiversidad y el funcionamiento de los ecosistemas. Si bien este proceso ha sido ampliamente estudiado en macroorganismos, existen escasos estudios enfocados en entender las invasiones biológicas a nivel microbiano. Para comprender este proceso en microorganismos, utilizamos un ensayo descrito previamente por nuestro laboratorio, el cual utilizó al hongo Trichoderma harzianum como invasor y 2 comunidades fúngicas diseñadas en base a la hipótesis de naturalización de Darwin, muestreadas a los 0, 3, 10, 20 y 30 días post-invasión: (i) comunidades filogenéticamente distantes al invasor (Comunidades No-Relacionadas), donde T. harzianum se establece exitosamente; y (ii) comunidades filogenéticamente cercanas a T. harzianum (Comunidades Relacionadas), donde éste no logra establecerse. Si bien la competencia estaría implicada en el éxito del invasor, es necesario considerar que T. harzianum podría utilizar otras estrategias para asegurar su establecimiento, como por ejemplo el micoparasitismo mediante quitinasas, o la autoprotección frente a la degradación de éstas. Para evaluar si estas capacidades influyen en el éxito del invasor, se realizó una cuantificación relativa (qRT-PCR) de los transcritos génicos codificantes de quitinasas de T. harzianum y un gen codificante para la proteína de autoprotección celular QID74. Se observó que, a partir de los días intermedios del ensayo, T. harzianum presenta una sobreexpresión tanto de los genes chit33, chit37 y chit42 como de qid74 en las Comunidades No-Relacionadas. Estos resultados sugieren que tanto el micoparasitismo como la capacidad de autoprotección de T. harzianum tendrían un rol determinante en el éxito invasivo de este hongo.

263 Demonstration of capacity of C-924 strain to form biofilm and effects of synthetic compounds analogous to sapogenins

Demostración de la capacidad formadora de biopelícula de la cepa C-924 y efecto de compuestos sintéticos derivados de sapogeninas

Rolando Morán1, Laritza Domínguez1, Ileana Sánchez1, Aylin Nordelo1, Liszoe Galdós1, Ramón Franco1, Danalay Somonte1, Nemecio González1. (1) Investigación y Desarrollo, Centro de Ingeniería Genética y Biotecnología (CIGB) de Camagüey

Biofilm formation is a mechanism of interaction between microorganisms and surface interfaces that confers advantages for colonization and survival. In the case of beneficial microorganisms that are formulated as biological products, the formation of biofilms can facilitate their mechanisms of action and enhance their biological activity. The main aim of this study was to evaluate the capacity of C924 strain (active ingredient of biological nematode control product HeberNem®) to form biofilm. For this purpose, the violet crystal method in microtitle plates was used as “in vitro” assay. For “ex vivo” assay, it was developed a method of interaction between C924 andArabidopsis thaliana roots. As result, it was demonstrated for the first time that C924 strain possesses the ability to form biofilms, which may be part of its mechanisms of action or at least to be an enhancer for such quality. This finding opens new possibilities for a thorough characterization of C924 strain mechanisms of action as well as it makes possible biological activity improvements. It was further demonstrated that synthetic compounds analogous to sapogenins may increases the biofilm formation capacity of this biocontrol agent. This result is a useful tool to develop biofilm induction studies for testing the effect of such compounds on improving the efficacy of new bioproduct formulations based on microorganisms

264 Sphingobacterium sp. CIGBTb a potential biofertilizer and biocontrol of plant diseases

Sphingobacterium sp. CIGBTb, un biofertilizante potencial y biocontrolador de enfermedades de plantas

Rolando Morán1, Ileana Sánchez1, Danalay Somonte1, Rosa Basulto2, Idania Wong 1, Eulogio Pimentel3, Jesús Mena4, Yassel Ramos5, Luis Javier González5. (1) Investigación y Desarrollo, Centro de Ingeniería Genética y Biotecnología (CIGB) de Camagüey (2) Aseguramiento y Control de Calidad, Centro de Ingeniería Genética y Biotecnología (CIGB) de Camagüey (3) Dirección General, Centro de Ingeniería Genética y Biotecnología (4) Regulaciones, Centro de Ingeniería Genética y Biotecnología (5) Dirección de Investigaciones Biomédicas, Centro de Ingeniería Genética y Biotecnología

The use of bacteria as fertilizers and controllers of plant diseases is an alternative to the chemicals that harm the ecosystem. In this work the bacteria CIGBTb isolated from eggs of Trichostrongylus colubriformis was identified by conventional and molecular methods. The effectiveness of CIGBTb to reduce the infestation ofMeloidogyne sp was evaluated in vitro and in vivo. In addition, antifungal properties and growth-promoting effects of the bacteria were determined. Phosphate solubilization, and IAA secretion were detected as well as some possible pathogenic traits against fungi and nematodes. In vitro treatment with Sphingobacterium sp CIGBTb resulted in 87 % inhibition of hatch of Meloidogyne spp eggs. This bacteria reduced the infestation index and the number ofCucurbita maxima root nodules. CIGBTb also promoted the growth of Lycopersicon esculentum and it reduced the gall index and root nodules. The number of egg per mass was also reduced. Strain CIGBTb antagonized in vitro with some pathogenic fungi. The strain had tripsine, chitinase, chitosanase sterase and phosphatase enzymatic activities as possible pathogenic traits according to the results of the APIZYM kit. The presence of a serine protease in the supernatants of cultures with nematicidal activity was identified by mass spectroscopy. CIGBTb produces IAA and was able to solubilize phosphate in NBRIP and Pikowskaya media. These results suggest that CIGBTb could be used in plants as a biocontrol and growth promoting agent.

265 Nematicidal bacterial strain CIGBc 8 induces systemic resistance in Arabidopsis thaliana and Solanum lycopersicum

Cepa bacteriana nematicida CIGBc 8 induce resistencia a nivel sistémico en Arabidopsis thaliana y Solanumlycopersicum

Rolando Morán1, Liszoe Galdós1, Laritza Domínguez1, Dulemys Carrazana1, Ramón Franco1, Ileana Sánchez1, Aylin Nordelo1, Raúl González1, Danalay Somonte1. (1) Investigación y Desarrollo, Centro de Ingeniería Genética y Biotecnología (CIGB) de Camagüey

The beneficial microorganisms can induce the activation of the immune system of the plants at local and systemic level. One of the objectives of the present work was to evaluate the capacity of the nematicidal bacterial strainCIGBc8, to modulate systemically the expression of resistance marker genes in tomato (Solanum lycopersicumL.) and Arabidopsisthaliana. In addition, in tomato plants through a split root system, the systemic effect of the CIGBc8 strain against Meloidogyneincognita was determined. In all the studies an application of a bacterial suspension of 1010cfu /mL was performed on the roots of plants. An inducer effect of the CIGB8c strain on the PDF1.2gene in leaves of Arabidopsisthaliana was obtained as a result. The expression of osmotin, hydroperoxide lyase, chitinase, glutathione peroxidase, phenylalanine-ammonia lyase and PR1 genes was observed in tomato. In the tomato assay againstMeloidogyneincognita, the strain showed a systemic effectt to induce resistance to this phytopathogen. The results obtained are an evidence that in addition to the direct nematicidal action of the CIGBc8 strain, it can protect the plant against pathogens through the modulation of the defense system.

266 Functional characteristics of the symbiont microorganisms of Antarctic sponges, analyzed by comparative genomics

Características funcionales de los microorganismos simbiontes de esponjas antárticas, analizadas mediante genómica comparativa

Mario Moreno-Pino1,2, Juan A Ugalde3, Nicole Trefault4,1. (1) Centro GEMA- Genómica, Ecología y Medio Ambiente, Universidad Mayor (2) Programa de Doctorado en Genómica Integrativa, Vicerrectoría de Investigación, Universidad Mayor (3) Universidad Mayor (4) Centro de Genómica y Bioinformática, Universidad Mayor

El microbioma de esponjas se compone de una amplia gama de microorganismos cuya función es relevante para la esponja y para el funcionamiento de los ecosistemas. Desafortunadamente, el estudio del rol funcional y las adaptaciones genómicas al estilo de vida simbiotico de las baterias asociadas a esponjas antárticas ha sido limitado. Este trabajo se centró en analizar el potencial metabólico de microorganismos aislados desde la esponja antártica Iophon sp.: Nesterenkonia sp. E16_10 y E16_7, Sporosarcina sp. E16_3 y E16_8, y Cellulophaga sp. E16_2, mediante su secuenciación genómica. Adicionalmente, se utilizaron 13, 43 y 17 genomas de Nesterenkonia, Sporosarcina y Cellulophaga, respectivamente, para realizar genómica comparativa. El análisis filogenómico y de identidad nucleotídica promedio (ANI) mostró que las cepas de Nesterenkonia y Sporosarcina corresponden a nuevas especies de bacterias. La genómica comparativa reveló que las cepas Nesterenkonia E16_10 y E16_7 poseen proteinas únicas relacionadas con la sintesis de ácidos grasos (Acetil-CoA carboxilasa, Biotin carboxilasa, proteina carrier de Biotina) y un número importante de genes relacionados al sistema Restricción-Modificación.Sporosarcina sp. E16_3 y E16_8 poseen proteina únicas relacionadas con la hidrólisis de carbohidratos (Alfa-galactosidasa, endo-beta-n- acetylglucosaminidasa) y múltiples transposones. Cellulophaga E16_2 posee proteinas exclusivas relacionadas con la respuesta de infección por fagos y respuesta a estrés y varios genes codificantes de proteinas de tipo eucariontes. En conclusión, los resultados muestran que todos los aislados secuenciados poseen adaptaciones al estilo de vida simbiótico y al extremo ambiente antártico.

Agradecimientos a los proyectos INACH DG_12-17, INACH RT_34-17 y Fondecyt Nº1190879

267 Metabolic analysis of the water kefir grains fermentation main products for the development of a functional drink based on panela

Análisis metabólico de los principales productos de la fermentación de gránulos de kéfir de agua para el desarrollo de una bebida funcional a base de panela

Laura Muñoz1, Michael Seeger 1, Pedro Valencia 2, Alejandra Urtubia 3, Andrea Carvajal 4, Beatriz Cámara1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología DAL , Universidad Técnica Federico Santa María (2) Laboratorio de Biocatálisis, Ingeniería Química y Ambiental, Universidad Técnica Federico Santa María (3) Laboratorio de Biorreactores, Departamento de Ingeniería Química y Ambiental, Universidad Técnica Federico Santa María (4) Departamento de Ingeniería Química y Ambiental, Universidad Técnica Federico Santa María

Water Kefir grains (WKG) are a microbial consortium consisting of lactic-acid bacteria, acid-acetic bacteria, bifidobacteria, and yeasts, embedded in exopolysaccharide. WKG transforms sucrose aqueous solutions (such as panela) into metabolic products such as alcohols and organic acids. Generally, fermented WKG beverages are artisan, but currently, these products are trying to industrialize, so standardizing the process is necessary, which is affected by variables such as the concentration, inoculum composition and substrate, the agitation and the cultivating temperature. Central Composite Design (DCC) is used to find conditions for optimal fermenting. In this study, we used WKG and panela solutions at concentrations of 80 g/L in 500 mL culture volume. Fermentations were accomplished with DCC, varying agitation (0 - 160 RPM), temperatures (20 - 40 °C), for 96 hours. Ethanol, lactic acid, acetic acid, and sugar were measured using an HPLC, and WKG wet weight were evaluated at the endpoint. As a result, the WKG increased between 8.84 and 35.12 g/L; sugar consumption was between 68.42 and 29.62 g/L, ethanol production between 0.70 and 2.55 g/L, lactic acid formation between 1.3 and 9.3 g/L and acetic acid production between 0.4 and 0.95 g/L. Multivariate regression models validated that only lactic acid has a linear relationship with the variables analyzed, whereas the agitation does not contribute to the process. This could be attributed to the orbital agitation type, which may not be suitable due to the WKG density. These results allowed to obtain standardized operative conditions for cultivating our WKG that satisfies sensorial responses.

CONICYT Ph.D. Scholarship 21160460, Regular Fondecyt N°1171555, Conicyt PIA ACT172128.

268 Abundance of phosphorus-solubilizing bacteria in lichen substrate and surrounding forest soil of the Reserva Nacional Coyhaique, Chile

Abundancia de bacterias solubilizadoras de fósforo en sustrato liquénico y suelo de bosque aledaño de la Reserva Nacional Coyhaique, Chile

Cecilia Muster1, María Camila Morales1, Margarita Carú1, Julieta Orlando1. (1) Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile

Los suelos de bosques están influenciados por el contenido de fósforo (P) foliar de los árboles que allí habitan. Antecedentes sugieren que un alto contenido de P en la cobertura arbórea generaría suelos con mayor concentración de P. No obstante, este depósito, el P se encuentra mayoritariamente inaccesible para la biota, siendo fundamental la participación de microorganismos del suelo para su solubilización. Los líquenes son componentes de labiota criptogámica de bosques y consisten en asociaciones simbióticas entre un hongo, un alga verde y/o una cianobacteria. Un componente liquénico adicional lo constituyen las bacterias asociadas, las cuales participarían en la solubilización de P, entre otras funciones. Con la finalidad de adquirir mayor conocimiento sobre la dinámica del P en suelo asociado a líquenes (sustrato) y suelo aledaño a éstos en bosques, evaluamos la disponibilidad de P y la abundancia de bacterias solubilizadoras de P presentes en ambos microambientes. Las muestras se recolectaron en 3 sitios de la Reserva Nacional Coyhaique: (i) bosque nativo maduro, (ii) bosque nativo renoval y (iii) bosque nativo reforestado con pinos. La disponibilidad de P se cuantificó mediante fraccionamiento secuencial y la abundancia de bacterias solubilizadoras de P mediante qPCR utilizando marcadores relacionados a solubilización de P. Cuanto mayor es la disponibilidad de P, menor es la abundancia de solubilizadores de P en el suelo de estos bosques. Por el contrario, el sustrato no presenta esta relación, observándose una disminución de la influencia de la cobertura arbórea sobre los solubilizadores de P por acción del liquen.

FONDECYT 1181510

269 Microbial nitrifying assemblages in seamounts of the Pacific Ocean off Valparaíso, Chile

Ensamble microbiano nitrificante en montes submarinos del Océano Pacífico frente a Valparaíso, Chile

Isabel Cristina Navarrete1, Marcela Cornejo2, Alejandro Murillo3, María Jesús Galvez1, Pierre-Amaël Auger2, Verónica Molina1. (1) Departamento de Biología, Observatorio de Ecología Microbiana, Universidad de Playa Ancha de Ciencias de La Educación (2) Pontificia Universidad Católica de Valparaíso (3) Structural and Computational Biology Unit EMBL - Heidelberg, Germany (Sponsored by Verónica Andrea Molina Trincado)

Los montes submarinos del Pacífico Sudoriental O’Higgins (MO), Juan Fernández 5 (JF5) y 6 (JF6) han sido caracterizados como sitios de alta productividad primaria y biodiversidad asociados a una gran dinámica oceanográfica que incluye remolinos de mesoescala originados desde la zona costera de Chile-central. En este estudio se determinó la influencia de las condiciones oceanográficas de los montes sobre la actividad de microorganismos nitrificantes (oxidantes de amonio a nitrito y de este último a nitrato); arqueas amonio oxidantes (AOA) (ecotipos A, B y Nitrosopumilus maritimus), bacterias amonio oxidantes (Betaproteobacteria-AOB) y Nitrospina (bacteria nitrito oxidante dominante en Zonas de Mínima de Oxígeno, ZMO), mediante qPCR con ensayos específicos de la subunidad A del gen amoA para AOA y AOB y 16 S rRNA para Nitrospina. Los resultados mostraron una abundancia de grupos activa (RT-qPCR) variable de este ensamble entre los montes y en su distribución vertical; las AOA-A y Nitrosopumilus maritimus fueron más activas en la oxiclina, en cambio, AOA-B y Nitrospina en la ZMO. Nitrospina y AOA-A fueron los grupos más activos principalmente en el monte MO, único sitio donde se detectó AOB. En comparación a los otros montes, el MO, el más costero, presentó una mayor estratificación, una oxiclina pronunciada (5,8 - 1,1 ml O2 L) y una ZMO (< 1 ml/L) mejor definida vinculada a la presencia de Aguas Ecuatoriales Subsuperficiales. En total nuestros resultados muestran una distribución de ensambles nitrificantes relacionada con la dinámica oceanográfica de los montes e indican una mayor actividad en la oxiclina.

Fondecyt 1171324 y Proyecto FIP N° 2014-04-2

270 Molecular identification of photoautotrophic organisms in a marine sponges from Pacific Coast of Costa Rica

Identificación molecular de organismos fotoautótrofos en esponjas marinas de la Costa Pacífica de Costa Rica

Valeria Navarro-Cascante1, Rodolfo Umaña-Castro2, Karol Ulate-Naranjo1. (1) Escuela de Ciencias Biológicas , Ciencias Exactas y Naturales, Universidad Nacional de Costa Rica (2) Laboratorio de Análisis Genómico, Escuela de Ciencias Biológicas , Ciencias Exactas y Naturales, Universidad Nacional de Costa Rica

The mutualist association between sponges and cyanobacteria have been amply reported at Caribbean Sea in America, but not at Pacific Ocean. These complex and diverse interactions between marine sponges and their symbiotic microbial communities have been compared to holobionts. However, these ecosystems have been threatened by the current anthropogenic impact, which puts their ecological balance at risk. Therefore, this project allows to analize the ecology and evolutionary history of these animals, in addition to generate indispensable information given the lack of studies regarding photosymbiotic organisms associated with sponges on the coasts of the American Pacific. The main aim of this study was to determine the molecular presence of photoautotrophic organisms associated with marine sponges of the Aplysina and Axinella genera at the Costa Rican North Pacific. The tissue of the marine sponges was macerated using a mechanical disrupter and the isolation of genomic DNA was performed using an optimized CTAB protocol. Molecular detection was performed by conventional PCR using universal primers for 16S ARNr region from cyanobacteria: CYAN738f-CYAN128Ir and CYAN106f-CYAN781r. Through Sanger sequencing and phylogenetic analyses was confirmed the presence of cyanobacteria Synechococcus sp. in Aplysina sp. and Axinella sp. sponges, with 87% bootstrap support. Likewise, another taxonomic cluster with 100% bootstrap value, confirms the presence of possible bacteria of the Anaerolineae family (phylum Chloroflexi) within the Aplysina sp. tissue. This study reports by the first time the presence of potential photoautotrophic organisms association with sponge tissue from America Pacific Coast, but, further studies are needed to elucidate the morphological and functional characteristics of these marine microorganisms.

Laboratorio de Análisis Genómico de la Escuela de Ciencias Biológicas de la Universidad Nacional

271 Genomic insights into the metabolism and evolution of the extremely acidophilic methanotrophs of the bacterial phylum Verrucomicrobia

Perspectivas genómicas del metabolismo y la evolución de los metanotrofos extremadamente acidófilos del filo bacteriano Verrucomicrobia

Gonzalo Neira1,2, Eva Vergara1, Carolina Gonzalez1,3, David Holmes1,3. (1) Center for Bioinformatics and Genome Biology, Fundación Ciencia y Vida (2) Bioquímica, Ciencias Químicas y Farmaceuticas, Universidad de Chile (3) Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor

Members of the phylum Verrucomicrobia are gram negative bacteria that root near the base of the Tree of Life. One family within the phylum inhabits extremely acidic environments (pH < 3). This family, which we term Methylacidiphilaceae, consists of the only known organisms able to oxidize methane in extremely acidic environments. Previous studies have focused only on the methanotrophic properties of the Methylacidiphilaceae and not on other properties that could help in deciphering their evolution. We address this hiatus by integrating phylogenomic and comparative genomics approaches. Phylogenomic inferences indicate that the Methylacidiphilaceae can be divided in two different clades distinguished by optimal temperature growth (one moderately thermophilic clade and one mesophilic). Genes involved in the methanotrophy pathway (pmoCAB), nitrogen fixation (nif) and carbon fixation (rbcS/L) were identified in all genomes. Whole genome-based comparisons were used to propose a taxonomic classification from species to order. Applying comparative genomics, we find that all organism share a core genome of about 800 genes. Several horizontal gene transfer events were predicted to play crucial roles in shaping the evolutionary differences between the different species of theMethylacidiphilaceae . The extremely acidophilic bacteria of Verrucomicrobia are a poorly understood but important lineage as they are the most abundant methane oxidizers in geothermal environments. Our research expands our knowledge of the genetic diversity and evolution of this lineage.

Programa de Apoyo a Centros con Financiamiento Basal AFB170004 to Fundación Ciencia and FONDECYT 1181717

272 Riverine bacterial microbiome in Chinese rivers: regional and local factors shaping bacterioplankton communities

Microbioma bacteriano en los ríos de China: factores regionales y locales que afectan las comunidades bacterianas acuáticas

Juan Pablo Niño1, María Carolina García-Chaves1, Chang-Ping Yu3,2, Anyi Hu4. (1) Universidad de Antioquia (2) Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, , Chinese Academy of Sciences (3) Graduate Institute of Environmental Engineering, National Taiwan University (4) Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences

The structuring of bacterioplankton communities in rivers is a complex process that results from the interaction between the growth of populations under particular local conditions and the immigration of cells from surrounding habitats, driven by the flow of water across the landscape. In order to explore how these processes shape riverine bacterial communities across the landscape, we analyzed, by sequencing the 16S rDNA using ILLUMINA Hi-Seq, the changes in bacterial microbiome composition across 11 rivers located in China Mainland and along a transect of about 400 Km within each river. As these rivers span a large gradient of geographic and environmental conditions, we were able to show that at large regional, scale variables like annual mean precipitation and annual mean temperature explain an important proportion of the variation in riverine bacterial composition across Chinese rivers. However, we identified coherent changes in bacterial microbiome of all the sampled rivers from upstream to downstream, regardless of its geographic position. Therefore, at this scale, the dynamics of bacterial taxa along this aquatic continuum seems to be driven by the movement of water through the landscape.

273 Optogenetic control and multi-fluorescence imaging of growing bacterial populations

Control optogenético e imágenes de multi-fluorescencia de poblaciones bacterianas en crecimiento

Isaac Núñez2,1,3, Tamara Matute2,3, Timothy Rudge1, Fernan Federici5,4, Fernan Federici7,6,5. (1) Ingeniería Química y bioprocesos, Ingeniería, Pontificia Universidad Católica De Chile (2) Instituto de Ingeniería Biológica y Médica, Pontificia Universidad Católica De Chile (3) Instituto Milenio de Biología Integrativa (iBio), Pontificia Universidad Católica de Chile (4) Center for Genome Regulation, Fondo de Desarrollo de A?reas Prioritarias (5) Instituto Milenio de Biología Integrativa (iBio) (6) Facultad de Biología, Departamento de genética molecular y microbiología, Pontificia Universidad Católica de Chile (7) Center for Genome Regulation, Fondo de Desarrollo de Áreas Prioritarias

Understanding spatial organization in cell populations is a major challenge in microbial ecology, biofilm research, and tissue engineering. Integrative approaches that combine computational tools, controllable inputs and synthetic genetic systems of minimal complexity would allow the development of theoretical frameworks to study these phenomena. While Synthetic Biology has enabled the construction of reliable synthetic gene networks, the open hardware movement has facilitated designs and tools to build controllable environments and inputs. Synthetic ecological relationships between growing population of cells that can be controlled with external hardware will provide tractable model systems. Here we describe an open hardware and synthetic biology platform to perform optogenetic manipulation of communities of bacterial colonies growing on hard-agar surfaces and record their dynamic behavior. The system is composed of two-wavelength optogenetic control, green light (520 nm) and red light (660 nm), which are used as environmental signals to trigger synthetic genetic circuits in E. coli cells. The device includes blue (470 nm) and white light illumination to perform multi-fluorescent and brightfield imaging. The hardware is based on a Raspberry Pi computer and camera with software control and analysis via Python, making easy to set different experimental regimes. Overall, the system allows optogenetic control and time-lapse imaging at scales ranging from single colonies to whole plate micro-ecosystems. This system will provide valuable tools and techniques for the study of microbial ecology under controlled conditions, as well as enabling engineering approaches via synthetic gene circuits.

Instituto Milenio de Biología Integrativa (iBio) Fondecyt Iniciacion 11161046

274 Whole genome hybrid assembly for comparative genomics of Antarctic bacteria

Ensamblaje híbrido de genoma completo para estudios de genomica comparativa en bacterias de la Antártica

Kattia Núñez-Montero2,1, Andrés Santos1, Jaime Martinez-Urtaza3, Leticia Barrientos1. (1) Ciencias Básicas, Medicina, Universidad de La Frontera (2) Biología, Biología, Instituto Tecnológico de Costa Rica (3) Centre for Environment, Fisheries and Aquaculture Science (CEFAS)

Microorganisms from Antarctic environments have been proposed as a promising source of multiple biotechnological applications, such as cold-stable enzymes, pigments, bioremediation and secondary metabolites for pharmaceutical industry. It has been hypothesized that Antarctic microorganisms possess unique features that help them to survive in the extreme environment, which can be exploited for biotechnology. However, the bacterial adaptative mechanisms to the Antarctic polar region have been poorly studied. Furthermore, reference genomes from Antarctic isolates are scarce on the databases, limiting the possibilities for comparative genomics studies. In this work, we applied a novel approach on whole genome sequencing to obtain reference genomes from bacterial Antarctic strains for comparative genomics, deciphering some unique features from this extremophile microorganisms. To this aim, the genomes of Antarctic bacteria Streptomyces fildesensis So13.3 and the Sphingomonas alpina So64.7 strains were sequenced by both, Illumina (Hi-seq) and Oxford Nanopore technologies (MinION). Low quality reads were filtered and adapters were eliminated using Trimmomatic and NanoFilt/Porechop, respectively. Hybrid assembly was conducted using Unicycler and quality was assessed by Quast and CheckM. The reference genomes were successfully assembled in one unique contig for both strains with high quality and completeness near to 100%. S. fildesensis resulted in a 9.56Mb genome with 70.4% GC, 8990 CDS and 87 RNA while S. alpina has a 5.06Mb genome with 63.5% GC, 4923 CDS and 51 RNAs. Preliminary comparative genomics analyses showed that Antarctic species devoted a higher percentage of its total genome for the biosynthesis of secondary metabolites, including infrequent types such as lassopeptides.

Instituto Antártico Chileno (INACH RT_14‒12), Universidad de La Frontera (DI17–0116), Network for Extreme Environments Research (NXR17-0003) and Doctoral Grant CONICYT‒PFCHA/Doctorado Nacional/2017‒21170263.

275 The planktonic microbiome of the Atacama trench

El microbioma planctónico de la fosa de Atacama

Francisca Ignacia Olivares1, Salvador Ramírez-Flandes1, Osvaldo Ulloa1. (1) Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción (Sponsored by .)

Las fosas oceánicas son los lugares más profundos del océano, superando los 6000 m bajo la superficie. En estos ambientes de alta presión (61.6 MPa) y bajas temperaturas (1 - 2.5 ºC) domina la vida microbiana. Actualmente, se conocen treinta y tres fosas, sin embargo, han sido caracterizadas las comunidades microbianas planctónicas de cuatro: la Fosa de Puerto Rico en el Océano Atlántico Nor-occidental y, de forma más exhaustiva, las fosas de Las Marianas, Kermadec y Japón del Océano Pacífico Occidental. En este trabajo se caracteriza por primera vez la comunidad microbiana planctónica de la fosa de Atacama ubicada frente a la costa de Chile-Perú. Esta fosa es la única existente en el Pacífico Sur Oriental encontrándose hidrográficamente aislada de otras. Mediante Illumina HiSeq se secuenciaron las regiones V4 y V5 del gen 16S ARNr de bacterias y arqueas de esta fosa para hacer su identificación taxonómica. Se consideraron dos fracciones de tamaño: 0.2 - 3 μm y 3 - 20 μm para caracterizar a los microorganismos de vida libre y asociados a partículas, respectivamente. Los taxa más representados en la fosa de Atacama son Thaumarchaeota, Bacteroidetes, Gammaproteobacteria, Marinimicrobia, Planctomycetes, SAR11 y otras Alphaproteobacteria. Cabe destacar que el clado SAR11 presenta mayores abundancias relativas en la fosa de Atacama que en las otras fosas del Pacífico Occidental, tanto en la fracción de vida libre (12 - 20%) como en la asociada a partículas (3 - 12%). Esta caracterización taxonómica se complementará a futuro con análisis funcionales de estos microorganismos.

Instituto Milenio de Oceanografía

276 In vivo spatial distribution and subcellular localization of FtsZ Anabaenain sp. PCC7120 by time- lapse microscopy

Distribución espacial y localización subcelular in vivo de FtsZ en Anabaena sp. PCC7120 mediante microscopía time-lapse

Jorge Olivares1, Derly Andrade1, Silva Marcial1, Sebastián Velozo1, Octavio Monasterio2, Mónica Vásquez1. (1) Departamento de Microbiología y Genética Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Universidad de Chile

A key event in bacterial cell division is the septation process, whose main component is FtsZ. This protein forms the Z-ring in the middle of the cell, which is the scaffolding for other division proteins. Super-resolution microscopies in models like Escherichia coli and Bacillus subtilis have shown that the Z-ring discontinuous, and live cell imaging studies have shown that FtsZ moves along the ring following a mechanism known as treadmilling, as its structural analog (tubulin) in eukaryotic cells. In cyanobacterial species, there are only studies of Z-ring’s structure in the unicellular model Prochlorococcus, but not in multicellular and filamentous cyanobacteria. To determine the spatial distribution of FtsZ in the Z-ring of filamentous cyanobacteria, we builded a FtsZ protein fused to sfGFP under the control of the native promoter in Anabaena sp. PCC7120. The mutant strain obtained by triparental conjugation and homologous recombination was completely segregated. Using confocal microscopy, it was determined that the FtsZ-sfGFP mutant has a wild type phenotype. The Z-ring in this mutant is discontinuous and, throughtime-lapse microscopy, a rotation and constriction of the Z-ring (in a time scale of seconds and hours, respectively) was observed. This is the first study in which the spatial organization andin vivo dynamics of the Z-ring is observed in a cyanobacterial model using a fusion protein and a complete allelic replacement, which allows us to understand how cell division occurs in multicellular bacteria and opens new questions regarding the function of the distribution patterns of FtsZ during the cell cycle. Grant Fondecyt 1161232

CONICYT-PCHA/Doctorado Nacional/2019-21191389

277 Meet MEET in sulfate-reducing bacteria: from pure cultures to complex communities

Explorando transferencia extracelular de electrones en bacterias reductoras de sulfato, desde cultivos puros a comunidades complejas

Roberto Andres Orellana1, Gabriela Arancibia2, Taha Diego2, Michael Seeger2. (1) Biologia, Facultad de Ciencias Naturales Exactas, Universidad de Playa Ancha de Ciencias de La Educación (2) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Universidad Técnica Federico Santa María

Las comunidades microbianas de ambientes anóxicos están normalmente dispuestas de una manera espacial discreta, en diferentes capas de acuerdo con una secuencia dictada por la disponibilidad de dadores y aceptores de electrones y la energía asociada a cada reacción redox. En general, mientras que la respiración de nitratos que genera la mayor ganancia de energía domina ambientes superficiales, la reducción de sulfato y metanogénesis, se restringen a capas más profundas. Recientemente, múltiples líneas de evidencia han desafiado esta visión tradicional sobre la compartimentalización de los procesos redox. Nuestro proyecto investiga la capacidad metabólica de bacterias reductoras de sulfato (SRB) para llevar a cabo la transferencia extracelular de electrones (MEET). Este mecanismo confiere a ciertos microorganismos la capacidad de intercambiar electrones con minerales insolubles, una capacidad que se pensaba era compartida solo por un selecto grupo de metabolismos reductores de metales. En este trabajo, reportamos la capacidad de MEET de la SRB, Halodesulfovibrio aestuarii. Asimismo, exploramos su genoma encontrando una serie de genes que dan cuenta de la capacidad de intercambio extracelular de electrones, incluyendo genes codificantes para quinonas y citocromos extracelulares. Adicionalmente, reportamos la capacidad MEET de una comunidad sulfidogénica nativa que reside en los estuarios de Mantagua, Valparaíso, la que es sensible a la adición de distintos dadores de electrones. Los resultados de nuestro trabajo sugieren que MEET se encuentra extendido en varios clados de SRBs, y que probablemente, corresponde a una herramienta que les permite competir, cuando el sulfato u otros aceptores de electrones solubles no están disponibles

Proyecto PAI-Insercion 79170091

278 High efficiency of nuclear transformation of the microalgae Nannochloropsis oceanica by Tn5 transposon system and analysis of different phenotypes of lipid accumulation

Alta eficiencia de transformacion nuclear de la microalga Nannochloropsis oceanica mediante el uso del transposón Tn5 y análisis de los diferentes fenotipos mutantes de acumulación de lípidos

Hector Marcelo Osorio1, Carol Jara1, Bernardita Cayupe1, Mónica Vásquez1. (1) Genética Molecular y Microbiologia, Ciencias Biologicas, Pontificia Universidad Catolica de Chile

Microalgae are photosynthetic organisms useful to obtain biofuels, since they have a high efficiency of biomass production and are able to accumulate a large amount of intracellular lipids. However, the profitability ofthe production of biomolecules from these organisms requires not only the optimization of cultivation and production conditions but also the genetic improvement of the species to be used. In this work we describe the discovery of new genetic elements involved in the biosynthesis of triglycerides (TAGs) in the microalga Nannochloropsis oceanica (N.O.) to produce strains with greater ability to produce TAGs. The use of transposons of random insertion of type Tn5 with markers of selection to antibiotics commanded by viral promoters allowed us to obtain selectable clones with altered phenotypes in lipid production.This strategy was accompanied by a large-scale identification and selection system for mutants, such as flow cytometry analysis with cell selection (FACS), allowed us to obtain clonal of each mutant. The identification and characterization of some of these mutants by RESDA-PCR and DNA sequencing, allowed us to discover new genes involved in the regulation of lipid synthesis, revealing possible responses at the cellular level influencing the intracellular homeostasis of lipids. Among these is a gene that coding for a putative haloacid dehalogenase-like hydrolase (HAD) possibly involved in the laminarin synthesis route was important in the high lipid accumulation (HL) phenotype and a gene encoding a putative ufm1-specific protease, implicated in endoplasmic reticulum (ER) homeostasis, was involved in the low lipid phenotype.

Fondecyt No. 1161232; Grant Conicyt REDES 180084; COPEC 2017.J.905

279 Colony formation in single-cell picocyanobacteria: different grazers same effect

Formación de colonias en picocianobacterias : distinto predador mismo efecto

Juliana Ospina-Serna1, Paula Huber2, Mariana Odriozola1, Fernando Unrein1. (1) Instituto Tecnológico de Chascomús, Laboratorio Ecología Acuática, Universidad de San Martin (2) Instituto Nacional de Limnologia, Universidad Nacional del Litoral

Picocyanobacteria (cells <2µm) can be found either as single-cells (Pcy) or embedded in a mucilaginous sheath as microcolonies or colonies (CPcy). It has been demonstrated that phenotypic plasticity in picocyanobacteria (i.e. the capability of single-cells to aggregate into colonies) can be induced as a response to predation pressure by flagellates. Here, we compared the effect of different predators on the morphological composition of natural communities of picocyanobacteria, and also evaluated the effect of infochemicals on the capability to form colonies in a Pcy strain. In the first experiment, the natural plankton community from a hypertrophic shallow lake was exposed to the direct contact of different predators (cladocerans and rotifers). The abundance of aggregated cells significantly increased in all treatments with zooplankton respect to the control, while the abundance of Pcy decrease. In the second experiment, we evaluated the aggregation capability in a picocyanobacteria strain isolated from the same system, by adding medium conditioned by different grazers (flagellates, rotifers and small cladocerans). The number of cells forming colonies was significantly higher in the treatments with conditioned medium regardless the predator, which suggest that Pcy has the capability to aggregate into CPcy even without a direct contact with any predator, most probably due to the presence of a chemical signal dissolved into the water. In summary, our results provide firm evidences that the formation of colonies in single-cells picocyanobacteria can be induce as a response of the predation pressure exerted by protists but also by different larger grazers like cladocerans and rotifers.

Proyecto de Investigación Cientifica y Tecnologica (PICT) 2016-1079

280 Different molecular approaches to study anammox communities

Diferentes aproximaciones moleculares para estudiar comunidades anammox

Pia Karina Oyarzua1, Claudia Etchebehere2, Patricia Bovio2, María Eugenia Suárez1. (1) Ingenieria quimica, biologica y ambiental, Ingenieria, Universitat Autonoma de Barcelona (2) Laboratorio de Ecología Microbiana, BIOGEM, Instituto de Investigación Biológica Clemente Estable

Anaerobic ammonium oxidation bacteria (anammox) have the metabolic ability to oxidize ammonium and nitrite to form nitrogen gas. Its application is now a proven technology and constitute a robust, reliable and cost-effective system, to treat effluents with high concentration of nitrogen but a relatively low level of organic carbon. DNA/ RNA-based molecular techniques are the most widely used approaches available for detecting this group of microorganisms, due at its very slowly growth rate and that have not been isolated in pure culture. The aim of this work was studying the anammox community composition of a granular sludge anammox reactor operated at stable conditions for more than one year, using different molecular approaches. Using FISH-CLSM technique in granule slices, a total of 42±10% of anammox bacteria was detected, using specific fluorescent probes was also possible to detect at species taxonomic level. Amplicon 16S rRNA gene sequencing was performed with two sets of universal primers 515F-806R and 515F -906R for bacteria and different coverage of our target group was detected, identifying at genus level a 65 and 29% of Candidatus Brocadia, respectively. Using metagenome analysis, a total of 42 genomes were assembled with over 80% of completeness, 3 of them correspond to Candidatus Brocadia. According to our results, each molecular approach has a bias and the use of several techniques are necessary to recover more reliable information. A better understanding of the community structure of the reactor will contribute to optimize a large- scale process design.

CONICYT PFCHA/DOCTORADO BECAS CHILE/2017 72180362

281 Water metagenomic analysis of La Punta and La Brava lake system in the Chilean Atacama Desert

Análisis metagenómico del agua del sistema lagunar de La Punta y La Brava en el desierto chileno de Atacama

Reynaldo Nuñez 2, Pamela Salinas 2, Carlos Salinas 2, Jorge Soto 2, Manuel Paneque1. (1) Ciencias Ambientales & Recursos Naturales Renovables, Facultad de Ciencias Agronómicas, Universidad de Chile (2) Agroenergía Ingeniería Genética S.A.

En Chile se describen 52 lagos andinos de gran altitud, que se distribuyen a lo largo del desierto de Atacama, entre ellos el sistema lagunar La Brava-La Punta en la región de Antofagasta. Este sistema lagunar tiene parámetros fisicoquímicos extremos de pH, temperatura, radiación, conductividad eléctrica y sus combinaciones, donde microorganismos extremófilos con capacidades fisiológicas amplias y versátiles son capaces de vivir. Una particularidad de este sistema lagunar es la alta salinidad que lo hace rico en extremófilos halófilos. En el presente trabajo se determinó la composición taxonómica del microbioma de 16 muestras de agua del sistema lagunar La Brava-La Punta, a partir de datos de secuenciación masiva del gen 16S ARNr. El análisis filogenético permitió identificar una población bacteriana constituida por 49 filos, 127 clases, 273 órdenes, 539 familias y 799 géneros. Entre los filos encontrados predominan Proteobacteria (45.3%), Bacteroidetes (29.3%), Actinobacteria (19.6%) y Verrucomicrobia (3.0%), con una abundancia relativa del 97.2%. Las clases más abundantes identificadas fueron Gammaprotebacteria, Alphaproteobacteria, Flavobacteria, Cytophagia, Actinobacteriay Verrucomicrobiae, que representan el 95.8% de la abundancia relativa del total de las muestras. Se realizaron correlaciones entre los parámetros fisicoquímicos y los niveles taxonómicos, mostrando que el pH es el factor de mayor influencia en la composición taxonómica (R2= 76%, p<0.05). La composición del ecosistema microbiano en esté sistema lagunar es altamente compleja y variable, por lo que es necesario ampliar nuestros estudios sobre microorganismos extremófilos en los lagos andinos de gran altitud, así como sus funciones ecológicas, que permitan desarrollar aplicaciones biotecnológicas.

282 Intra and inter specific variations of microbial communities associated with antarctic sponges and their functional potential

Variaciones intra e inter específicas de comunidades microbianas asociadas a esponjas antárticas y su potencial funcional

Génesis Parada-Pozo1, Antonia Cristi1, Felipe Morales1,3, César Cárdenas2, Nicole Trefault1. (1) Centro GEMA - Genómica Ecología y Medio Ambiente, Facultad de Ciencias, Universidad Mayor (2) Departamento científico, Intituto Chileno Antártico (3) Carrera de Biotecnología, Universidad de Antofagasta (Sponsored by Nicole Trefault Carrillo)

Los simbiontes microbianos de esponjas marinas cumplen funciones esenciales tanto para la nutrición y defensa de la esponja como para la ecología del ambiente marino. En el bentos antártico, las esponjas pueden llegar a ocupar el 80% de la superficie, por lo que el ensamble esponja-microorganismos es fundamental para la mantención de este ecosistema. En este trabajo, se analizaron las comunidades microbianas de 30 individuos de esponjas, representando 3 géneros distintos colectados en isla Doumer, costa oriental de la Península Antártica: Isodictya, Hymeniacidon y Haliclona. Estas comunidades fueron caracterizadas mediante la amplificación y secuenciación masiva del gen 16S rRNA y una posterior predicción de genes funcionales utilizando PICRUSt, con el fin de determinar patrones de variabilidad intra e inter específicos en la composición y potencial funcional de bacterias y arqueas simbiontes. En general, los perfiles microbianos revelan comunidades que son ampliamente semejantes entre diferentes individuos de cada especie con similitud intra especie entre 40 y 60%. En términos de abundancia, el core más conservado se mostró entre individuos del género Haliclona (n=10, 87%) seguido del Hymeniacidon (n=15, 75%) y de Isodyctia (n=4, 73%), entre estos, sólo un OTU fue compartido a nivel interespecie. Al analizar el potencial funcional, los resultados revelan que a pesar de la alta especificidad hospedero-huésped, las funciones inferidas son conservadas entre microbiomas de esponjas marinas antárticas que habitan la Bahía Sur de la Península Antártica.

Fondecyt Nº11150129, INACH RT_34-17 y Fondecyt Nº1190879

283 Spatial variability of epilithic biofilms on intertidal rocky shores: zonation or chance?

Variabilidad espacial de biopelículas epilíticas del intermareal rocoso: ¿zonación o azar?

Belén Pareja1, Clara Arboleda2,1, Sergio A. Navarrete3,2,4, Rodrigo De La Iglesia1,3. (1) Departamento de Genética Molecular y Microbiología, Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Departamento de Ecología, Estación Costera de Investigaciones Marinas, Pontificia Universidad Católica de Chile (3) Marine Research and Innovation Center (MERIC) (4) Center for Applied Ecology and Sustainability (CAPES), Pontificia Universidad Católica de Chile

El estudio de la variabilidad espacial de los organismos a través de gradientes ambientales nos permite entender los procesos abióticos que modulan sus distribuciones y abundancias, y las interacciones entre sí y con su entorno. En el intermareal rocoso chileno las comunidades microbianas pueden presentarse en forma de biopelículas epilíticas y/o epibiontes y llegar a determinar la trayectoria de sucesión de la comunidad de macroorganismos, quienes mediante su distribución espacial definen tres bandas de zonación cuasi-discretas (zona alta, media y baja) a través del gradiente. Por lo tanto, se desea comprobar si las comunidades microbianas intermareales también se distribuyen formando bandas de zonación o lo hacen de manera relativamente azarosa. Para esto se analizaron las biopelículas presentes en muestras de roca, obtenidas desde las tres zonas del intermareal rocoso. Usando microscopía óptica y electrónica de barrido se identificaron los morfotipos microbianos más abundantes y sus densidades poblacionales. Además, se analizaron los patrones de restricción enzimáticos de amplicones de los genes 16S y 18S rRNA mediante el coeficiente de disimilitud de Bray-Curtis y Escalamiento Multidimensional No-Métrico. Se observó quelas cianobacterias filamentosas son más abundantes en la zona alta y las diatomeas dominan en la baja. Además, la composición comunitaria microbiana de las biopelículas varía a través del gradiente ambiental, siendo la zona alta y media más parecidas entre sí que con respecto a la baja. Entonces, se sugiere de manera preliminar que existen diferencias entre las comunidades microbianas de las biopelículas asociadas a las tres zonas del intermareal rocoso.

Marine Research and Innovation Center (MERIC).

284 Meridional distribution of active nitrifying communities in the coast of Chile from 29°10´S to 41°40´S

Distribución meridional de comunidades nitrificantes activas en las costas de Chile desde los 29°10’S a los 41°40’S

Hermann Peña1, Isabel Navarrete1, Marcela Cornejo2, Verónica Molina1. (1) Observatorio de Ecología Microbiana, Ciencias Naturales y Exactas, Universidad de Playa Ancha (2) Escuela de Ciencias del Mar, Pontificia Universidad Católica de Valparaíso

El proceso de nitrificación es un proceso desarrollado por organismos quimioautotrófico que oxida elamonio aeróbicamente a nitrato vía nitrito y fija carbono inorgánico. En el océano, este proceso es realizado por un ensamble de microorganismos que incluye arqueas y bacterias oxidantes de amonio y de nitrito (AOA, AOB, NOB). Dentro de este último grupo funcional nitrificante se destaca al género Nitrospina spp el cual se acoplaría principalmente con la actividad de AOA. El objetivo de este estudio fue determinar la distribución meridional de comunidades superficiales nitrificantes activas y su relación con variables oceanográficas. Las muestras para la extracción de RNA (n=20) fueron colectadas entre la latitud 29°10’S a 41°40’S a lo largo del veril de 500 m durante julio-agosto de 2018 (FIP-MERLUZA), además de datos fisicoquímicos durante el crucero. Las comunidades nitrificantes fueron cuantificadas mediante RT-qPCR. Los resultados muestran una mayor actividad del grupo Nitrospina en el norte (2,23x10^3 n° de copias 16S rRNA/ng) en comparación al sur (1,92x10^1 n° de copias 16SrRNA/ng). La variación de la actividad se asoció con altas concentraciones de nitrato (máximo 16 μM) y bajas concentraciones de oxígeno (mínimo 3,37 mL/L). Igualmente, el coeficiente de correlación de Spearman dio cuenta de una relación significativa (p ≤ 0,05) de la actividad nitrificante con el oxígeno y nutrientes (nitrato, fosfato). En total nuestros resultados sugieren una mayor actividad nitrificante en el norte lo cual es posible asociar a variables vinculadas a la surgencia costera en superficie (disminución de oxígeno y aumento de nutrientes).

FONDECYT 1171324 y FIP Merluza 2018 (IFOP 1049-45-LE18)

285 Composition of methanogenic consortia and degradation of organic acids exuded by rice roots

Composición de consorcios metanogénicos y degradación de ácidos orgánicos exudados por raíces de arroz

Luciana Pereira Mora1, Johanna Triver Salomon1, Ana Fernández Scavino1. (1) Laboratorio de Ecología Microbiana y Microbiología Ambiental, Facultad de Química, Universidad de la República

El arroz es un cultivo importante económicamente para Uruguay que se desarrolla en condiciones de inundación y por tanto constituye una de las principales fuentes antropogénicas de emisión de metano, un potente gas de efecto invernadero. La máxima emisión se da durante la floración, donde la planta exuda ácidos orgánicos por las raíces. La degradación de esos compuestos implica, al menos, una fermentación bacteriana que produce acetato e hidrógeno que son utilizados por archaeas metanogénicas para producir metano. Hasta la fecha, no se ha descripto la ecofisiología de los consorcios bacterianos degradadores de estos ácidos, lo cual permitiría predecir y mitigar la producción de metano para hacer el cultivo más sustentable. En este trabajo se caracterizaron consorcios microbianos degradadores de dos de los principales ácidos presentes en los exudados de la planta de arroz: tartárico y succínico, a partir de suelo de cultivo de arroz con diferentes antecedentes. Los resultados de secuenciación masiva del gen ARNr 16S indican que la comunidad metanogénica se diferencia según el cultivo previo (soja, arroz o pasturas). La producción de metano a partir de tartrato fue más rápida y similar en los distintos suelos con la misma composición en los consorcios degradadores. En cambio, los consorcios degradadores de succinato fueron más diversos y diferentes en su composición respecto a los seleccionados con tartrato. La degradación de tartrato y succinato produjo diferentes intermediarios metabólicos. Estos resultados indicarían que los sustratos se degradan por vías diferentes y seleccionan comunidades con eficiencias diferentes en la producción de metano.

FCE_1_2017_1_136722

286 Analysis of the plasmidome of Puquio de Campo Naranja, a high-altitude lake from the Andean Puna

Análisis del plasmidoma de Puquio de Campo Naranja, una laguna de altura de la Puna Andina

Maria Florencia Perez1, Daniel Kurth1, Genis Andres Castillo Villamizar2, Rolf Daniel2, María Eugenia Farías1, Julián Rafael Dib1. (1) PROIMI-CONICET (2) Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Georg-August University of Göttingen

Las lagunas de altura de la Puna Andina están expuestas a múltiples condiciones extremas incluyendo alta radiación UV, alta concentración de arsénico, metales pesados y sales disueltas, elevada amplitud térmica y baja presión de oxígeno. Entre ellas se destaca Puquio de Campo Naranja en el Salar de Antofalla, a 3340 metros sobre el nivel del mar (Catamarca, Argentina). A pesar de las condiciones inhóspitas, diversos ecosistemas microbianos pueden desarrollarse exitosamente mediante mecanismos de adaptación, que pueden estar codificados en plásmidos y pueden ser así transmitidos en la comunidad microbiana. El objetivo de este estudio fue la caracterización del plasmidoma (población plasmídica total) de organismos cultivables y no cultivables de Puquio de Campo Naranja, analizando sus funciones y significancia ecológica. Se buscaron determinantes genéticos de naturaleza plasmídica esenciales para sobrevivir en este ambiente. Para ello, se realizó la extracción y secuenciación del ADN plasmídico total de microbialitos de dicha laguna. El análisis de los datos reveló gran proporción de genes que codifican para proteínas de función desconocida (39%). Se encontraron genes relacionados con la adaptación a este ambiente, incluyendo genes de resistencia al estrés oxidativo, estrés osmótico y shock térmico, resistencia a antibióticos y metales pesados, genes de reparación del ADN y genes que codifican factores de virulencia. Estos resultados resaltan el rol clave que cumplen los plásmidos en un determinado nicho y la importancia de su estudio para comprender los ambientes microbianos. Este trabajo constituye el primer estudio sobre elementos extracromosomales en conjunto de un ambiente extremo de la Puna.

287 Antimicrobial potential of bacteria isolated from the marine sponge Aplysina caissara collected in the north coast of São Paulo (Brazil)

Potencial antimicrobiano de una bacteria aislada de la esponja marina Aplysina caissara recolectada en la costa norte de Sao Paulo (Brazil)

Luiza Carminato1, Andressa A. M. Ramaglia1, Márcio Reis Custódio2, Cristiane C.P. Hardoim1. (1) não aplica-se, Universidade Estadual Paulista (2) Departamento de Fisiologia Geral (IB) e Centro de Biologia Marinha (CEBIMar), Universidade de São Paulo

Marine sponges harbor diverse bacterial communities in which complex interactions are established. It is known that several bioactive compounds obtained from these animals are synthesized by the associated bacterial communities. In this survey, bacteria were isolated from the sponge Aplysina caissara collected in the coast of São Paulo, Brazil. The microorganisms were identified by 16S rRNA gene sequencing, and their capacity to synthesize antimicrobial compounds were tested against pathogenic bacteria. In total, 36 bacteria were obtained from A. caissara on R2A medium, belonging to: Actinobacteria (Micrococcus); Bacteroidetes (Aquimarina and Aureiviga); Firmicutes (Bacillus, Brevibacillus, Cohnella, Fictibacillus, Lysinibacillus, Oceanobacillus and Staphylococcus); Gammaproteobacteria (Acinetobacter); and some unclassified below phyla level. When submitted to dual antagonistic assay on BHI and R2A, 15 of them demonstrated the potential of producing antimicrobial substances and inhibited both the growth of Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (ATCC 27853). The obtained results also reveal an improved growth of these bacteria in R2A than on BHI medium and a greater inhibitory action on S. aureus, presenting halos with an average diameter of 15 mm. One bacteria identified as belonging to the genus Fictibacillus, revealed the greatest inhibitory action, with a 30 and 18 mm halo against S. aureus and P. aeruginosa, respectively, on R2A medium. These results suggest that a simple cultivation approach can yield putatively novel bacteria species. Furthermore, almost one half of the isolated strains from A. caissara produces bioactive substances capable of impairing the growth of S. aureus and P. aeruginosa, which demostrate their antimicrobial capacity.

São Paulo Research Foundation (FAPESP, process number 2016/17189-7).

288 Novel regulators of antibiotic biosynthesis in an enterobacterium model

Nuevos reguladores de biosíntesis de antibióticos en una enterobacteria modelo

Daniel Plaza1, George Salmond1. (1) Biochemistry, Biological Sciences, University of Cambridge

Antibiotic resistance is rapidly increasing worldwide reaching dangerous levels. New resistance mechanisms are arising and being globally disseminated which could endanger our ability to treat even common infections in the future. Moreover, the discovery of novel antibiotics has dramatically plummeted in the last decades, mostly because of a profitability drop arising from the commercial effort. Thus, antibiotic resistance andthe lack of novel antibacterials loom as a huge problem for the health and welfare of both agriculture and humans. The enterobacterium Serratia sp. ATCC 39006 (S39006) is considered a model for the study of biosynthesis and regulation of diverse secondary metabolites, particularly two different antibiotics: a carbapenem and prodigiosin. Both compounds are tightly regulated by a range of molecules, which rely on physiological and environmental signals. Thus far, by using random transposon mutagenesis, 8 novel genes and intergenic regions associated with active transport systems, membrane biosynthesis, and central carbon metabolism, have been found. Their characterisation at structural and functional level are being analysed in order to understand their role in antibiotic biosynthesis modulation in the S39006 model. Deciphering unknown regulatory mechanisms may reveal novel processes involved in the antibiotic production that may prove exploitable, which embodies a valuable pursuit of solving the current and future antibiotics shortcomings.

Biotechnology and Biological Sciences Research Council (BBSRC), Becas Chile, and Cambridge Trust

289 Effect of supernatants of soil cyanobacterial cultures on the development of Polypogon australis plants

Efecto de sobrenadantes de cultivos de cianobacterias de suelo sobre el desarrollo de plantas de Polypogon australis

Darlyng Pontigo1, Marcela Wilkens2, Claudia Ortiz3. (1) Laboratorio de Microbiología Básica y Aplicada - Laboratorio de Bioquímica Vegetal y Fitorremediación, Facultad de Química y Biología, Universidad de Santiago de Chile (2) Laboratorio de Microbiología Básica y Aplicada, Facultad de Química y Biología, Universidad de Santiago de Chile (3) Laboratorio de Bioquímica Vegetal y Fitorremediación, Facultad de Química y Biología, Universidad de Santiago de Chile

Un suelo degradado es aquel que ha sufrido una pérdida de la capacidad para sustentar especies vegetales, sin embargo, existen plantas que pueden colonizar estos suelos espontáneamente, tales como la poácea nativa no endémica Polypogon australis. El establecimiento vegetal en suelos degradados se ha asociado a la presencia de cianobacterias, que son microorganismos fotoautótrofos y, algunos, fijadores de nitrógeno. Las cianobacterias de suelo interactúan positiva o negativamente con plantas mediante la producción de compuestos químicos, proceso denominado alelopatía. Para evaluar el efecto alelopático de 7 cultivos de cianobacterias aisladas desde muestras de suelo de la IV Región de Coquimbo, sobre la planta P. australis, se trató a semillas y plántulas con sobrenadantes de cultivos de 11 días en medio BG-11. Durante 14 días se evaluó el porcentaje de emergencia de coleóptilos, para luego desde el día 15 y hasta el día 25, determinar longitud foliar. A tiempo final (25 días) se midió peso fresco, contenido de proteínas, clorofila total y longitud radicular en las plantas. Los resultados mostraron que todos los sobrenadantes aumentaron significativamente el porcentaje de emergencia de coleóptilo, y 3 incrementaron la biomasa fresca de las plantas, comparado con el control agua. El sobrenadante del cultivoTrichormus sp. tuvo el mayor efecto tanto en la emergencia de coleóptilo (100% de semillas tratadas), como en el aumento de la masa fresca (2,3 veces respecto al control). Este bioensayo mostró una relación alelopática positiva de los 7 cultivos de cianobacterias conP. australis, siendo Trichormus sp. el de mayor efecto.

Proyecto FONDEF IT17M10006.

290 Methanogenic and methanotrophic microbial communities in coastal wetlands of the semiarid zone of central Chile (ZSAChC) and its relationship with changes in conductivity

Comunidades microbianas metanogénicas y metanotrofas en humedales costeros de la zona semiárida de Chile central (ZSAChC) y su relación con cambios en la conductividad

Francisco Pozo1,2, Marcela Cornejo3, Julio Salcedo-Castro3, Manuel Contreras4, Roberto Orellana 4, Veronica Molina4. (1) Departamento de Biología , Ciencias Naturales y Exactas , Universidad de Playa Ancha de Ciencias de La Educación (2) Departamente de Biología , Ciencias Naturale y Exactas , Universidad de Playa Ancha de Ciencias de La Educación (3) Pontificia Universidad Católica de Valparaíso (4) Universidad de Playa Ancha de Ciencias de La Educación (Sponsored by Veronica Molina Trincado)

Los humedales costeros son fuentes de metano (CH4), un gas de efecto invernadero con un potencial de calentamiento global 25 veces mayor que el CO2. Este gas es generado desde la actividad microbiana metanogénica y metanotrófica que producen y consumen el CH4. En este estudio se determinó la variación de la estructura microbiana bentónicas y la potencial contribución de comunidades metanogénicas y metanotrofas mediante secuenciación i-tag16SrDNA (partidores 515f y 806r, región V4 para bacterias y arqueas) en humedales costeros hiposalinos y mesosalinos de la ZSAChC (33´77´S-29´82´S). Además, se analizaron parámetros físico-químicos incluyendo las concentraciones de

CH4 disueltas y su asociación con el microbioma de los humedales. En general, el microbioma de estos humedales se componen de 37 Phyla destacándose los Proteobacteria, Bacteroidetes y Cyanobacteria quienes representan el 50, 12 y 8% de la comunidad, respectivamente, mientras que las arqueas Euryarchaeota, Thaumarchaeota y Crenarchaeota representan ~3,1%, siendo las bacterias más diversas (H´) que las arqueas (5,94 versus 3,73). Los humedales presentaron concentraciones variables de CH4 disuelto (4.4 - 1107 nM), las que se correlacionaron negativa y significativamente con la conductividad. Además, la conductividad influyó sobre la estructura de comunidades metanogénicas y metonotróficas, presentando una mayor riqueza en humedales costeros mesosalinos (>20000 mScm-1), con una mayor predominancia de los géneros Methanosaeta, Methylophaga y Methylococcus. Nuestros resultados sugieren que la conductividad tiene un rol regulador sobre la estructura de comunidades metanogénicas y metanotróficas de los humedales costeros de la ZSAChC, implicando en una mitigación de los flujos de CH4 hacia la atmósfera.

291 Antibacterial activity elicitation of Antarctic actinobacteria strains

Elicitación de actividad antibacteriana en cepas de actinobacterias Antárticas

Damian Quezada-Solís1, Kattia Núñez-Montero2,1, Leticia Barrientos1. (1) Biociencias, Ciencias Básicas, Universidad de La Frontera (2) Biología, Biología, Instituto Tecnológico de Costa Rica

The antimicrobial resistance has proven to be a raising threat in the clinical setting, while the discovery of novel compounds with antimicrobial activity has decreased in the last years. Antarctic continent is an unexplored environment which has been proposed as a promising source of new antibiotics. Recent studies in genomics of actinobacteria have shown that most genes for secondary metabolites biosynthesis remain silent under usual culture conditions. Therefore, different culture conditions tests are suggested to elicit the expression of these silent genes, boosting the possibilities to discover new molecules. The aim of this study was to evaluate different culture conditions and elicitation treatments for the expression of secondary metabolites with antibacterial activity in Antarctic actinobacteria. Previously isolated actinobacteria strains (x35) were cultured in six different media and three elicitation treatments including co-culture, sodium nitroprusside and lipopolysaccharide. A crude extract was obtained from each culture using ethyl acetate extraction, which was then tested against three pathogens (Staphylococcus aureus ATCC-25923, Escherichia coli ATCC-25922 and Enterococcus faecalis) by disk diffusion susceptibility test. The results confirmed that secondary metabolites with antibacterial activity are produced depending on the culture condition. Particularly, the strain Streptomyces fildesensis So13.3 showed an increased antibacterial activity when cultured in media containing glucose, yeast and malt extract. Furthermore, the co-culture of strains Arthrobacter sp. Se18.01 and Knoellia aerolata Se62.02 exhibited a synergic effect against Gram-positive bacteria. Our study highlights the relevance of including a multi-culture condition screening to evaluate antimicrobial activity, specially for untapped environment bacteria. Instituto Antártico Chileno (INACH RT_14‒12), Universidad de La Frontera (DI17–0116), Network for Extreme Environments Research (NXR17-0003), Doctoral Grant CONICYT‒PFCHA/ Doctorado Nacional/2017‒21170263 from Comisión Nacional de Investigación Científica y Tecnológica (CONICYT).

292 Long term patterns of picocyanobacteria from a hypertrophic shallow lake inferred through flow cytometry

Estudio a largo plazo de las picocianobacterias en una laguna somera e hipertrófica utilizando citometría de flujo

Maria Victoria Quiroga1, Paula Huber2, Juliana Ospina-Serna1, Nadia Diovisalvi1, Mariana Odriozola1, Gerardo Cueto3, Leonardo Lagomarsino1, Jose Bustingorry 1, Roberto Escaray1, Horacio Zagarese1, Fernando Unrein1. (1) INTECH (UNSAM-CONICET) (2) INALI (UNL-CONICET) (3) IEGEBA (UBA-CONICET)

Picophytoplankton from eutrophic shallow lakes are generally underrepresented in global models. Here we analyzed picocyanobacteria (Pcy) dynamics along ten years (2007-2017) in the turbid hypertrophic shallow lake Chascomús (Pampa Plain, Argentina). We used flow cytometry to detect changes in Pcy organism abundance (either single-cell or colonial), chlorophyll-a content (FL3), organism size/granularity (SSC) and cytometric diversity indexes (flowDiv package for R) in relation to environmental conditions. Intra- and interannual changes (seasonality and trend) in the former Pcy features were evaluated through generalized additive models (GAM). A second GAM was tested for each response variable with environmental factors as predictors. Contrarily to other freshwater systems, Chascomús lake showed a Pcy seasonality with higher abundances during winter, while the interannual pattern resembled a dilution effect during wet periods. The winter Pcy community was less diverse and even, suggesting that this peak was due to the proliferation of few Pcy taxa. Pcy abundance, FL3, SSC, alpha cytometric diversity and evenness were partially explained by lake depth, turbidity, expected incident radiation and the rate of change of irradiance, unrevealing the importance of underwater light climate in this light limited turbid system. Cladocerans abundance was negatively associated with Pcy abundance and positively related with FL3 and SSC. The cladocerans effect was further asses through in vitro experiments. The cytometric fingerprint (beta diversity) detected differences in Pcy community structure strongly related with differences in cladoceran abundance among samples. These results suggest a possible induced shift from unicellular Pcy to microaggregates/colonial forms during periods of high cladoceran abundance. PICT 2016-1554, PICT-2016-1079

293 How marine animals impact microbial communities from Antarctic soils? A metagenomic approach

¿Cómo impactan los animales marinos a las comunidades microbianas de suelo Antártico? Una enfoque metagenómico

Lia Ramirez-Fernandez1, Luis Orellana2, Eric Johnston2, Konstantinos T Konstantinidis3,2, Julieta Orlando1. (1) Departamento de Ciencias Ecologicas , Facultad de Ciencias, Universidad de Chile (2) School of Civil and Environmental Engineering, Environmental Microbial Genomics Laboratory, Georgia Institute of Technology (3) School of Biological Sciences, Environmental Microbial Genomics Laboratory, Georgia Institute of Technology

Antarctic soils show generally low productivity, driven by low temperature, humidity and nutrient availability. However, animals can increase nutrient availability of ice-free areas transferring nutrients from marine to terrestrial ecosystems. In this study, we employed shotgun metagenomics and population genome binning techniques to reveal the impact of marine mammals and birds on soil microbial communities in Antarctic soils from South Shetland Islands (Livingston Island and King George Island), and analyzed the impact of animal presence over genes involved in nitrogen recycling pathways. We recovered ~100 metagenome-assembled genomes (MAGs) from 8 phyla, mainly Proteobacteria, Actinobacteria and Bacteroidetes.Rhodanobacter was the most representative genera in our samples; approximately 2% of all 16S rRNA reads from bird- and mammal- impacted soils were assigned to this genus. Similarly, Rhodanobacter was one of the most abundant MAGs recovered. However, MAGs identified asRhodanobacter appeared to represent distinct species. The presence of marine animals significantly decreased soil microbial diversity and changed the soil microbial structure by increasing the abundance of Proteobacteria and Bacteroidetes compared to adjacent control soils not affected by animal activity. In addition, soils influenced by animals showed an increase in the abundance of genes related to nitrogen recycling, in particular those related to the denitrification pathway. Therefore, this study advanced our understanding about the impact of animal activity over soil microbial populations in Antarctic and described the novel microbial diversity associated with these terrestrial ecosystems and the potential contribution of N2O emission on ice-free areas from terrestrial Antarctica.

This work was supported by Instituto Antártico Chileno (project DT_10_15 to LR), US National Science Foundation (award 1831582 to KTK) and CONICYT-PIA ACT172065, http://www.antarcticgenomics.cl, to JO) and PFCHA / Nacional Scholarship nº21140997.

294 Characterization of organoarsenical compounds transformation to inorganic arsenic mediated by an aerobic bacterial consortium

Caracterización de la transformación de compuestos organoarsenicales a arsénico inorgánico mediada por un consorcio bacteriano aeróbico

Javiera Ravanal1, Carla León1, Víctor Campos1. (1) Departamento de Microbiología, Facultad de Ciencias Biológicas, Víctor Lamas 1290 Casilla 160-C, 4070386 Concepción, Chile, Universidad de Concepción

Compuestos organoarsenicales (OAC), como roxarsona (ROX), nitarsona (NIT) y metanoarsonato monosódico (MSMA), han sido utilizados en la industria avícola y agrícola. Estas prácticas han incorporado OAC a los suelos, donde son degradados a arsénico inorgánico (IAs). El objetivo del trabajo fue caracterizar la transformación de ROX, NIT y MSMA a IAs, mediada por un consorcio bacteriano aeróbico (BC). BC fue crecido en ausencia (C) y presencia de 0,5 mM de ROX (CROX), 0,5 Mm de NIT (CNIT), 0,5 mM de MSMA (CMSMA) y una mezcla de ROX, NIT y MSMA (0,5 mM final c/u) (CTODOS). Se caracterizaron las cinéticas de crecimiento por espectrofotometría y las cinéticas de transformación de los OAC mediante HPLC-HG-AAS. Los datos fueron modelados matemáticamente con el modelo de Weibull. La velocidad de crecimiento (k) de CROX (0,075±0,003 ODnm∙h-1) no presento diferencias significativas respecto de C (0,075±0,004 ODnm∙h-1). Las k de CNIT (0,048±0,003 ODnm∙h-1), CTODOS (0,054±0,003 ODnm∙h-1) y CMSMA (0,061±0,004 ODnm∙h-1) disminuyeron significativamente respecto al control. Las velocidades -1 -1 - de transformación de OAC (C/C0) en orden creciente fueron: 0,026±0,004 mg·l ∙h (CTODOS), 0,038±0,010 mg·l 1∙h-1 (CNIT), 0,039±0,004 mg·l-1∙h-1 (CROX) y 0,088±0,027 mg·l-1∙h-1 (CMSMA). Los porcentajes de transformación a IAs (IAs%) en orden creciente fueron: 96,57±0,094% (CTODOS), 96,69±0,131% (CROX), 96,95±0,056% (CNIT) y 97,21±0,169% (CMSMA). Dados los altos IAs% obtenidos, BC podría ser utilizado en la implementación de un proceso biotecnológico que efectúe la transformación hasta arsénico inorgánico de los OAC generados por la industria avícola y agrícola.

295 Characterization of PGP traits of endophyte bacteria isolated from four extreme Chilean environment plants

Caracterización de rasgos promotores del crecimiento vegetal en bacterias endofitas aisladas desde cuatro plantas de ambientes extremos de Chile

Joaquin Ignacio Rilling1,3,4, Javiera Flores2, Nitza Inostroza4, Jacquelinne Acuña3,4, Milko Jorquera3,4. (1) Doctoral Program in Science of Natural Resources, Facultad de Ingenieria y Ciencias, Universidad de La Frontera (2) Bioquimica, Facultad de Ingenieria y Ciencias, Universidad de La Frontera (3) Scientific and Technological Bioresource Nucleus (BIOREN-UFRO), Facultad de Ingenieria y Ciencias, Universidad de La Frontera (4) Applied Microbial Ecology Laboratory, Departamento de Ciencias Quimicas y Recursos Naturales, Facultad de Ingenieria y Ciencias, Universidad de La Frontera

Plant growth-promoting (PGP) bacteria are proposed since 1990 as a potential alternative to chemical fertilization in agriculture. In this study, forty two endophytic bacteria (genotyped different as revealed by ERIC-PCR) were isolated from roots and shoots of plans grown in Patagonia (Gaultheria mucronata, Hieracium pilosela), and Atacama Desert (Distichis spicata and Pluchea absinthoides). PGP traits were assessed as follow. Firstly, indol-3-acetic (IAA) production, phosphate (P)-solubilizing ability, 1-aminocyclopropane-1-carboxylic acid deaminase (ACCD) activity and halotolerance (2~10% NaCl) we assayed in all isolates. Secondly, the presence of PGP-related genes (acdS, phoD, phoC and phoX) in their genomes was evaluated by PCR. Finally, the isolates were taxonomically affiliated based on 16S rRNA gene sequences. The results revealed that 84% of isolates showed P-solubilizing ability. The ACCD activity was observed in all isolates (ranging 4.6~20.15 μmol α-ketobutyrate mg-1 h-1). The IAA was only produced by four isolates (ranging 0.1~1.3 mg l-1), but the remain of isolates were able to produce other unidentified tryptophan-induced auxins. 57% of isolates presented halotolerance at 10% NaCl. PCR reactions revealed the presence of the acdS gene in two isolates meanwhile phoD and phoC were detected in six and five isolates, respectively. Sequencing revealed that most isolates were affiliated to Bacillus and Serratia genera in both environments. This study provides evidence on the presence of potential PGP bacteria in the endosphere of plants from Chilean extreme environment plants. This study was funded by FONDECYT Regular project no. 1160302. Authors also acknowledge the laboratory support of projects FONDECYT Initiation no. 11160112, and JICA/JST SATREPS project code JPMJSA1705.

296 Biocementation of tailings mediated by Bacillus subtilis LN8B and seawater

Biocementación de relaves mediada por Bacillus subtilisLN8B y agua de mar

Dayana Arias1,2, Ximena Urzúa2, Luis Cisternas1, David Jeison3, Mariella Rivas2. (1) Ingeniería Química y Procesos de Minerales, Facultad de Ingeniería, Universidad de Antofagasta, Avda. Angamos 601, Antofagasta, Chile (2) Biotecnología, Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Avda. Angamos 601, Antofagasta, Chile (3) Escuela de Ingeniería Bioquímica, Pontificia Universidad Católica de Valparaíso, Avda. Brasil 2085, Valparaíso, Chile

Los relaves son considerados uno de los principales residuos de la industria minera, existiendo gran preocupación por las posibles consecuencias para la salud humana que pueden generar sus contaminantes, entre ellos, la liberación de material particulado. Por este motivo, se realizaron ensayos de biocementacion de tierras de relave conla bacteria ureolítica halotolerante Bacillus subtillis LN8B. Se evaluó la sobrevivencia de esta cepa bacteriana a distintas concentraciones de relave y la capacidad de biocementarlos mediante MICP en columnas durante un periodo de 5 y 15 días. Los relaves biocementados con respecto al control fueron analizados mediante ensayos de resistencia mecánica y difracción de rayos X (DRX). Los resultados demuestran que B. subtilis LN8B tolera un 1% p/v de relave alcanzando una densidad celular igual a 3 ×109 cél/ml con respecto al control igual a 4 ×109 cél/ml en 48 h. Con respecto al biocemento formado en ensayo de columna, en el día 5 se obtuvo el mejor resultado corroborado por pruebas de resistencia a la compresión soportando 13 kg a diferencia de 9 kg en el control. Los resultados de DRX indican que existe un aumento del porcentaje de CaCO3 en relaves biocementados hasta un 7,8% en comparación a un 4% del control sin tratar. Los resultados obtenidos indican que B. subtilis LN8B podría ser utilizada para biocementar relaves en presencia de agua de mar eliminando la dispersión de material particulado al ambiente con un alto contenido de metales pesados como Cu, Hg y Pb.

Proyecto Anillo ACM170005 - Tailings and seawater: from end-of-pipe toward cleaner production; Proyecto Fondecyt 1190664 – Microbial and enzymatic induced calcite precipitation as a tool to improve mine tailings sustainability.

297 Chloride Stress Induces Osmotic, pH and Oxidative Stress in Leptospirillum ferriphilum DSM14647

La exposición a NaCl induce estrés osmótico, acidificación del citoplasma y estrés oxidativo en Leptospirillum ferriphilum DSM14647

Javier Ignacio Rivera1,2,3, André Pollender3, Michael Schlömann3, Gloria Levicán2. (1) Escuela de Post grado, Ciencias, Universidad de Chile (2) Departamento de Biología, Facultad de Química y Biología, Universidad De Santiago De Chile (3) Environmental microbiology, Institute of Biosciences, TU Bergakademie Freiberg

In acidophilic microorganisms, anions like chloride have higher toxicity than their neutrophilic counterpart. In addition to the osmotic imbalance, in acidophiles chloride can also induce acidification of the cytoplasm. We predict that intracellular pH decrease produces an increase in the respiratory rate and the reactive oxygen species (ROS) generation, and therefore oxidative stress can also be induced. In this study, the multifactorial effect as inducing osmotic imbalance, cytoplasm acidification and oxidative stress in the iron-oxidizer bacterium L. ferriphilum DSM 14647 exposed to 100 mM NaCl was investigated. Results showed that chloride stress up-regulates genes for synthesis of potassium transporters (kdpC and kdpD), and biosynthesis of compatible solutes (hydroxy)ectoine (ectC and ectD) and trehalose (otsB). In addition, the intracellular level of both hydroxyectoine and trehalose increased significantly, suggesting a strong response to keep osmotic homeostasis. On the other hand, the intracellular pH significantly decreased from 6.7 to pH 5.5 and the oxygen consumption increased significantly when the cells were exposed to NaCl stress. Furthermore, this stress condition led to a significant increase of intracellular reactive oxygen species content, and activation of antioxidant cytochrome cperoxidase (CcP) and thioredoxin (Trx) activities. In agreement, ccp and trx genes were up-regulated under this condition, suggesting that this bacterium display a transcriptionally regulated response against oxidative stress induced by chloride. These results allow us better understand the multifactorial effect of chloride-stress and decipher the molecular bases that support the extreme sensitivity in acidophilic bacteria.

Financial support was provided by grants from the government of Chile Fondecyt 1170799 and USA1799. JRA was supported by Conicyt fellowship. TH was funded by Biohydrometallurgical Center Freiberg of the Dr. Erich-Krüger foundation.

298 Biochemical and microbiological soil analyses at the aggregate level in no-till agriculture field assays in Argentina. Effects of crop rotation

Análisis bioquímico y microbiológico de suelos agrícolas bajo siembra directa en Argentina. Efectos de la rotación de cultivos a nivel de agregados

Natalia Belén Robledo1, Luciano Andrés Gabbarini1, Luis Gabriel Wall1. (1) Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes

En Argentina, se cultivan más de 20 millones de hectáreas con el sistema de Siembra Directa (SD). La SD, junto con la rotación de cultivos, mejora la calidad física de los suelos en comparación con labranza convencional o monocultivo. La estructura física del suelo se ha relacionado históricamente con la actividad de la fauna del suelo, pero serían las bacterias y los hongos los principales factores de formación y estabilización de los agregados de suelo. En ensayos a campo con 5 niveles de intensidad y diversidad en la rotación de cultivos (IIR), hemos visto que el aumento de IIR conduce a mayores rendimientos y a una mejora en la salud del suelo. Los resultados del fraccionamiento mediante el tamizado en húmedo muestran que el aumento del IIR incrementa significativamente la proporción de fracciones de macroagregados del suelo con un alto porcentaje de reproducibilidad. La medición de actividades enzimáticas de los agregados muestra perfiles diferenciales según el tamaño de las fracciones y del IIR. El análisis de diversidad microbiana mediante la secuenciación masiva del gen 16S de ADN extraido directamente del suelo, muestra una estructura de comunidad bacteriana diferencial entre los macro y microagregados y el suelo sin fraccionar y entre suelos sometidos a rotación intensiva o monocultivo. Actualmente se encuentra en proceso el análisis de perfiles de lípidos totales a nivel de agregados cuyo resultado permitirá ampliar la discusión de los efectos de la rotación de cultivos sobre la biología del suelo a nivel de agregados.

299 A metabolomic approach for the study of the molecular signals involved in the early symbiotic interaction between a beta-rhizobium and its host plant

Estudio de las señales involucradas en la interacción simbiótica entre un beta-rizobio y su leguminosa hospedera, utilizando como aproximación la metabolómica

Maria Cecilia Rodriguez1, Laura Sandes1, Florencia Garabato1, Carolina Croci1, Mauricio Langleib2, Eduardo Da Silva Junior3, Andrés Iriarte 2, Mónica Tallarico Pupo3, José Sotelo4, Elena Fabiano1, Raúl Platero1. (1) Bioquímica y Genómica Microbianas (BIOGEM), IIBCE, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE) (2) Departamento de Desarrollo Biotecnológico, Facultad de Medicina, Instituto de Higiene (3) Laboratorio de Química de Microorganismos, Facultad de Ciencias Farmaceúticas de Riberao Preto, Universidad de San Pablo (4) Departamento de Genómica, IIBCE, Instituto de Investigaciones Biológicas Clemente Estable (IIBCE)

Rhizobia are soil bacteria belonging to the alpha and beta subdivision of proteobacteria, whose most notable characteristic is their ability to form symbiotic associations with plants of the Fabaceae family. The specificity of the interaction starts when both organisms mutually recognize in the rhizosphere by the exchange of molecular signals. Usually flavonoids and other compounds present in the exudates of the root of the host plants, act as inductor of the expression of the nod genes of rhizobia, responsible for the bacterial synthesis and secretion of Lipochito- oligosacharides molecules (nodulation factors), and are key molecules for the host plant recognition. However, the nature of inducing molecules naturally involved in these interactions have not been yet identified. In this work, we identify the molecular signals involved in the early steps of the model β-rhizobiumCupriavidus necator UYPR2512 and its host plant; Mimosa pudica. For this, Mimosa pudica plants were grown in hydroponic conditions in presence or absence of their symbiotic pair. The exudates lyophilized were subjected to SPE using a C18 column and the extracts were analyzed by HPLC-ESI-MS/MS. The mass pattern obtained was studied by Molecular Networking approach, using the Cytoscape program and the GNPS Molecular Networking database. Nineteen differentially expressed compounds were identified in the extracts from plants in presence of UYPR2512, suggesting the presence of β-rhizobium induces changes in the composition of the exudates. The role of the identified compounds will be further evaluated.

MOV_CA_2017_1_138164 PEDECIBA FCE_1_2014_104338 FCE_1_12017_136082

300 Pushing the Limits of Life to Extreme: a Microcosm Experiment to Explore Temporal Dynamics of Rare Bacterial Biosphere under different Environmental Stressors

Llevando los Límites de la Vida al Extremo: Un Experimento de Microcosmos para Explorar la Dinámica Temporal de la Biosfera Bacteriana Rara contra diferentes Factores De Estrés Ambiental

Sebastián Rodríguez2,1, Nicolas Miranda1,2, Vladimir Avalos2,3, Martha Hengst2,4, Verónica Molina5, Jeffrey Wade6, Cristina Dorador1,2,7. (1) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, CL (2) Centre for Biotechnology & Bioengineering (CeBiB), Chile (3) Centro de Bioinnovación Antofagasta (CBIA), Facultad de Ciencias del Mar y Recursos Biológicos , Universidad de Antofagasta, Antofagasta, CL (4) Laboratorio de Ecología Molecular y Microbiología Aplicada, Departamento de Ciencias Farmacéuticas, Universidad Católica del Norte, Antofagasta, CL (5) Departamento de Biología, Observatorio de Ecología Microbiana, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, CL. (6) Center for Environmental Diagnostics and Bioremediation, University of West Florida, Pensacola, FL, USA (7) Departamento de Biotecnología, Faculta de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, CL

“Rare Biosphere” (RB) constitutes the low-abundance and highly-diverse OTUs. This rarity serve as reservoirs of genetic diversity and perform important ecosystem roles. Previous studies revealed that high-altitude wetland Salar de Huasco (3800 masl) in the Chilean Altiplano exhibit poly-extreme environmental conditions, including solar radiation (1000 W/ m2), variable salinity (0.29 to 49.1 PSU), and temperature fluctuations (-10 to +25°C). These conditions are associated with constant change in microbial communities temporally and spatially. Nevertheless, relatively little is known about the processes and mechanisms promoting the development and maintenance of the RB. This study is to explore the response of temporal dynamics of the microbial RB against radiation, high salinity and both/combined. We developed an experimental approach, using an inoculum from a microbial mat cultivated in low-nutrient-heterotrophic medium, growing under UV-B and saline solution in a gradient of charge rates inside microcosms with controlled conditions. We used DNA metabarcoding and bacterial secondary production (BSP) for monitored microbial diversity and cellular activity respectively for 2 months. Bioinformatic analysis-approaches revealed 27 bacterial phyla, diversity increased from 14 to 18 phyla and most important changes of relative abundance were related to Proteobacteria (40-98%) and Cloacimonetes (1-20%). BPS support that members of the RB are active (~400 pmolC/Lhr highest response) during the experiment. This reveals that the RB changes and responds to perturbations in the environment. Therefore, it’s crucial to understand the succession dynamics across temporal scales to highlight the response of BR to extreme conditions, considered close to “limit of life”.

FONDECYT N° 1140179, 1181773

301 Long-chain flavodoxin FldX1 of Paraburkholderia xenovorans LB400 are involved in the resistance to the oxidizing agent paraquat

La flavodoxina de cadena larga FldX1 de Paraburkholderia xenovorans LB400 está involucrada en la resistencia al compuesto oxidante paraquat

Laura Rodríguez-Castro1, Roberto E. Durán1, Michael Seeger1. (1) Departamento de Química, Química, Universidad Técnica Federico Santa María

Paraburkholderia xenovorans LB400 is a model bacterium for the degradation of polychlorinated biphenyls and diverse aromatic compounds. The aerobic metabolism of these compounds produce reactive oxygen species, and therefore oxidative stress. Flavodoxins are small electron transfer proteins expressed in conditions of oxidative stress for cell redox balance. The overexpression of the long chain flavodoxin IsiB fromAnabaena sp. PCC7119 in bacteria increased survival in the presence of oxidizing agents. The aim of this study is to evaluate the protective effect of LB400 long- chain flavodoxins during oxidative stress inP. xenovorans LB400. Two genes encoding flavodoxins (Bxe_A0278 and Bxe_ B0391) were identified at the major chromosome (FldX1) and the minor chromosome (FldX2). A secondary structure prediction of FldX1 and FldX2 showed structural models similar to those previously described. Their genomic context showed genes encoding membrane proteins, transporters, proteins involved in redox processes and biosynthesis of macromolecules. A phylogenetic analysis indicates that they belong to different evolutionary clusters. The genes fldX1 and fldX2 were overexpressed in P. xenovorans LB400. Survival assays in presence the redox-cycling compound paraquat (1 and 20 mM) were performed with the recombinant strains. P. xenovorans strain overexpressing FldX1 showed a higher survival than the control strain at both concentrations of paraquat, while strain FldX2 displayed a protective effect only in 1 mM paraquat. A gene expression analysis revealed no induction of several antioxidant genes, predominantly in strain FldX1. In conclusion, the flavodoxin FldX1 encoded in the major chromosome of P. xenovorans LB400 confers protection during oxidative stress conditions.

FONDECYT 1151174 (MS), Anillo GAMBIO ACT172128 (MS) grants, Red RIABIN (LRC,MS), CONICYT PhD fellowship (LRC, 21170062) and CONICYT Gastos Operacionales scholarship (LRC, 21170062/2017).

302 Revealing the ‘Ribosomally active’ microbial eukaryotic communities in preserved samples from marine sediments

Desvelando las comunidades microbianas eucariontes “activas ribosomalmente” en muestras preservadas de sedimentos marinos

Raquel Rodríguez-Martínez1,2, Guy Leonard1, David S. Milner1, Sebastian Sudek4, Mike Conway4, Karen Moore1, Theresa Hudson1, Frédéric Mahé7, Patrick J. Keeling5, Alyson E. Santoro6, Alexandra Z. Worden3,4, Thomas A. Richards1. (1) Living Systems Institute, University of Exeter (2) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta , Universidad de Antofagasta (3) Ocean EcoSystems Biology , GEOMAR Helmholtz Centre for Ocean Research (4) Monterey Bay Aquarium Research Institute (5) Department of Botany, University of British Columbia (6) Department of Ecology, Evolution and Marine Biology, University of California (7) University of Montpellier

Marine sediments represent the largest carbon sink on Earth and it is one of the most important microbial-driven ecosystems, yet this environment is poorly characterized. In addition, due to the difficult sampling conditions, marine microbial eukaryotes have not been studied in detail in these environments, yet they are fundamental components of marine microbial food webs and biogeochemical cycles. In this work we are using a combination of diversity tag sequencing and meta-transcriptome analysis to understand microbial eukaryote diversity in marine sediments. Samples were taken from a cruise in the North Pacific Ocean (Monterey Bay) at depths of 200, 650, 881 and 956 metres using two approaches: injection of RNA Lifeguard in situ or when samples arrived at the surface. The study is based on RNA extractions, which were reverse transcribed into cDNA in order to obtain a diversity that likely represents ribosomally ‘active’ cells. We have characterised these communities using the V4 small subunit ribosomal RNA tag-sequencing approach using the Illumina MiSeq platform. Phylogenetic analysis of several Stramenopiles classes (Labyrinthulea, Thraustochytrids, Pseudofungi and uncultured marine stramenopile groups known as MAST) and Opisthokonta demonstrates a large diversity and relative abundance of these candidate groups, in example, the MAST-6 clade, a protist belonging to MAST, still not characterized due to the limited number of GenBank sequences (7) and ‘OTU97 pyrotags’ (BioMarKs dataset, 17). These results allow us to begin to explore community composition and function of eukaryotic microbes implicate in the marine carbon cycle in these difficult to sample environments. CONICYT FONDECYT INICIACIÓN 11170748 and Gordon and Betty Moore foundation grant (GBMF3307).

303 Revealing the complex structure of microbial mats in Antarctica by molecular tools and electron microscopy

Uso de herramientas moleculares y de microscopia electrónica para revelar la compleja estructura de tapetes microbianos de la Antártida

Diego M. Roldán1, Rodolfo J. Menes1. (1) Unidad asociada de Microbiología del IQB - Cátedra de Microbiología, Facultad de Ciencias - Facultad de Química, Universidad de la República

Los tapetes microbianos son ecosistemas en los cuales se establecen relaciones tróficas altamente complejas entre microorganismos con diferentes capacidades metabólicas, de las cuales la fototrofía puede tener gran relevancia. Están ampliamente distribuidos en diversas regiones del planeta, especialmente en zonas polares. En el presente trabajo se estudió un tapete proveniente de la Isla Rey Jorge (islas Shetland del Sur). La estructura de la comunidad microbiana se estudió por medio de secuenciación masiva (Illumina Miseq) de los genes ARNr 16S y 18S. Los resultados indican una gran biodiversidad y la presencia de 19 phyla de Bacteria, con la dominancia de Proteobacteria, Bacteroidetes y Cyanobacteria y 21 phyla de Eukarya, con predominancia de Bacillariophyta y Tardigrada. La observación macroscópica mostró que el tapete está constituido por tres capas diferenciadas y la tinción microscópica reveló la presencia de diversos protozoos, nematodos y rotíferos. Por microscopía confocal laser de barrido (CLSM) se estudió la distribución estratificada de los microorganismos y se contabilizó un elevado porcentaje de filamentos microscópicos autofluorescentes (40 % del total de células teñidas con DAPI). La microscopía electrónica de barrido (SEM) reveló la abundancia de diatomeas, que concuerda con los resultados moleculares. Además se empleó SEM- EDS para caracterizar la composición inorgánica mayoritaria. La fijación biológica de nitrógeno se estudió por medio del ensayo de reducción de acetileno, que solo se detectó en presencia de luz y a temperatura de 2°C, pero no a 15°C. No se registró actividad fijadora en oscuridad, con el agregado de glucosa como sustrato.

304 Dynamic of gut microbiota in Atlantic salmón (Salmo salar) fed a carbohydrate rich diet

Dinámica de la microbiota intestinal del salmón del Atlántico bajo una dieta experimental rica en carbohidratos

Alejandro Villasante1, Karina Kram1, Héctor Rodríguez1, Jaime Romero1. (1) Laboratorio de Biotecnología, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile

Los salmónidos como el salmón del Atlántico (Salmo salar), no exhiben un desempeño productivo óptimo cuando son alimentados con dietas ricas en polisacáridos de reserva. El objetivo de este estudio es evaluar la dinámica de la microbiota intestinal del salmón del Atlántico bajo una dieta experimental durante 12 semanas. Las tres dietas fueron: dieta alta en carbohidratos (HC/LP), dieta media en carbohidratos (MC/MP) o dieta baja en carbohidratos; con niveles crecientes (0, 15 y 30%, respectivamente) de polisacáridos de reserva. En cuanto a la composición de la microbiota intestinal,Firmicutes, Actinobacteria y Proteobacteria fueron los phyla más abundantes en los peces correspondientes a los tres grupos experimentales durante el estudio. Si bien, Firmicutes mostró ser el phylum dominante (60-78%) en los tres grupos experimentales hasta la semana 8, se observó un fuerte incremento en la abundancia relativa de Actinobacteria (40-50%) en los tres grupos experimentales (independiente al efecto dieta) hacia la semana 12. En particular, el análisis de Lefse indicó que los géneros Lactococcus, Haematobacter y Singulisphaera fueron significativamente más abundantes en el grupo HC/LP comparado con el grupo MC/MP en la semana 4. Mientras el género Enterococcus fue significativamente más abundantes en el grupo HC/LP comparado con el grupo MC/MP, tanto en la semana 8 como en la semana 12. En conclusión, nuestros resultados mostraron un efecto marginal del consumo de dieta con alto contenido de carbohidratos digestibles en la composición de la microbiota intestinal del salmón del Atlántico, afectando, principalmente, a bacterias de baja abundancia.

305 Microbiota de abalones (Haliotis rufenscens) de cultivo en individuos sanos y afectados por del síndrome del marchitamiento del pié (withering)

Microbiota of healthy and affected by withering syndrome cultured abalone Haliotis( rufenscens) individuals

Natalia Catalán1, Karina Kram1, Rodrigo Rojas2, Claudio D. Miranda2, Jaime Romero1. (1) Laboratorio de Biotecnología de los Alimentos, Instituto de Nutrición y Tecnología de los Alimentos (INTA), Universidad de Chile, Santiago, Chile (2) Laboratorio de Patobiología Acuática, Departamento de Acuicultura, Universidad Católica del Norte, Coquimbo, Chile

El abalón rojo (Haliotis rufenscens) es un importante recurso en la acuicultura chilena y además un interesante gasterópodo herbívoro. La microbiota de los herbívoros puede contribuir a la degradación de polisacáridos de las algas que consumen, por esta razón es importante el estudio de los microorganismos que componen la microbiota del abalón de cultivo y cómo puede ser modulada por dieta, enfermedades y factores ambientales. En este contexto, Candidatus Xenohaliotis californiensis es una bacteria intracelular de la familia Anaplasmataceae, que se describe en los epitelios gastrointestinales del abalón, y es considerada el agente causal del síndrome del marchitamiento del pié (Withering sindrome, WS), el cual puede ser crónico y letal. Los resultados del análisis metagenómico basado en 16SrRNA, muestran que la microbiota de abalones con síntomas de WS, presenta una composición diferente de los individuos sanos (PERMANOVA 0,002). Además, que los individuos con WS presentan hasta un 65% de abundancia relativa de Candidatus Xenohaliotis californiensis, mientras que en individuos sanos el promedio no supera el 5%; diferencia también señalada bajo el análisis de Lefse. A los individuos sanos se asociaron los géneros Ketogulonigenium y Roseobacter que ya han sido encontrados en ambientes marinos y asociados a otros eucariontes. Las bacterias del género Ketogulonigenium que tienen la capacidad de convertir azúcares en un precursor de la vitamina C, y las del género Roseobacter poseen vías claves para la degradación de osmolitos de azufre presentes en algas. Estos últimos además, se han propuesto como probióticos en larvicultura.

306 Partitioning of Autotrophic Carbon Fixation Pathways Along the Redox Gradient in Anoxic Marine Zones

Particionamiento de las vías de fijación autótrofa del carbono en zonas marinas anóxicas

Paula Sofía Ruiz1,2, Salvador Ramírez-Flandes1, Edwin Rodríguez-León1, Osvaldo Ulloa1. (1) departamento de ciencias naturales y oceanograficas, facultad de ciencias biologicas, Universidad de Concepción (2) Oceanografía, Ciencias, Universidad de Concepción (Sponsored by Instituto Milenio De Oceanografía)

Microbial processes in the waters of anoxic marine zones (AMZs) contribute to the loss of fixed nitrogen from the ocean. These microbial processes are recognised as key components of the oceanic nitrogen cycle. However, the nature and impact of such processes on the carbon cycle are insufficiently understood. Using metagenomic and metatranscriptomic data from AMZs worldwide, we report an explicit partitioning of the marker genes associated with different autotrophic carbon fixation pathways, along the redox gradients. The Calvin-Benson-Bassham cycle was the most ubiquitous along the gradient, while the reductive Acetyl-CoA pathway was restricted to suboxic and anoxic waters. Sequences putatively associated with the 3-hydroxypropionate/4-hydroxybutyrate cycle dominated in the upper and lower oxyclines. Genes related to the reductive tricarboxylic acids cycle were represented from dysoxic to anoxic waters. Taxonomic affiliation of the sequences is consistent with the presence of known microorganisms involved in the crucial steps of biogeochemical cycles in AMZs.

This study was supported by the Chilean National Commission for Scientific and Technological Research (grant Fondecyt 1161483) and the Millennium Science Initiative (grant IC 120019).

307 Comparative genomics of Enterococcus casseliflavus PAVET15, isolated from an infection of the cattle tick Rhipicephalus microplus

Genómica comparativa de Enterococcus casseliflavus PAVET15, aislado de una infección de la garrapata del ganado Rhipicephalus microplus

Luis Lozano1, Renaud Conde2, Raquel Cossío-Bayúgar3, Esthefan Miranda-Miranda4, Eduardo Hernández- Domínguez3, Víctor García5, Bernardo Sachman5. (1) Unidad de Análisis Bioinformáticos, Centro de Ciencias Genómicas, UNAM (2) Arbovirus, INSP (3) Artropodología, CENID-SAI, INIFAP (4) Hemiltología, CENID-SAI, INIFAP (5) Micología y Microbiología, Medicina, Universidad de Chile

Enterococcus casseliflavus es una cocobacteria gram positiva aislada de una presunta infección en la garrapata del ganado Rhipicephalus microplus, se identificó como PAVET15, y su genoma total fue reportado por nuestro equipo de trabajo. Hicimos la genómica comparativa, con respecto al genoma más cercano: E. casseliflavus E30 disponible en el NCBI. PAVET15 se distingue por contener 641 genes accesorios diferentes, mientras que E30 tiene 169 distintos con respecto a PAVET15. Encontramos rearreglos de genes, parecidos a los encontrados en E. gallinarum. PAVET15 presenta diversos genes involucrados en virulencia, probablemente expresados durante la infección a la garrapata del ganado, y diversos genes involucrados en la defensa contra otras bacterias como el Sistema Zeta toxina/antitoxina, que se había descubierto previamente en el plásmido de otra E. casseliflavus; también exhibe genes de protección celular y de reparación del ADN, así como genes que le confieren resistencia a antibióticos y transportadores de xenobiontes. Por lo cual, PAVET15 tendría los elementos de toxicidad contra artrópodos, y podría ser utilizada como biocontrol y coadyuvar en el control integral de la garrapata del ganado R. microplus. E. casseliflavus PAVET15 contiene los genes necesarios para mantenerse como saprofita-oportunista, y adaptarse a los desafíos que la naturaleza le impone.

Beca de Postdoctorado del CONACYT Apoyo para la Capacitación del INIFAP

308 Comparative virulome of environmental and clinical strains of Vibrio cholerae non-O1-no-O139 isolated in Chile in the period 1991-2018

Viruloma comparativo de cepas ambientales y clínicas de Vibrio cholera no-O1-no-O139 aislados en Chile en el período 1991-2018

Bernardo Sachman-Ruiz1, María Teresa Ulloa2, Gonzalo Osorio2, Luis Lozano3, Víctor García2, Natacha Monge4, John Rossen4, Camila Sanhueza2, Isabel Briceño5, Lorena Porte6, Jeannette Dabanch 6, Alberto Fica6, Mónica Lafourcade 7, Francisco Silva8, Loriana Castillo9. (1) Artropodología, CENID-SAI, INIFAP (2) Micología y Microbiología, Medicina, Universidad de Chile (3) UNAM (4) Molecular Unit Research, Centrum Groningen, Universitair Medisch (5) Hospital Naval Almirante Nef (6) Hospital Militar de Santiago (7) Clínica Santa María (8) Hospital Clínico Universidad de Chile (9) Hospital La Florida

Vibrio cholerae es una bacteria diarreogénica de alta incidencia en el mundo, todos los serotipos son capaces de sobrevivir en ambientes acuáticos, posibilitando así la ingesta directa o por contaminación de alimentos. Los serotipos toxigénicos O1 y O139 son la causa de las pandemias de cólera asociados al consumo de agua contaminada, produciendo un cuadro de gastroenteritis aguda potencialmente mortal. Las cepas de los serotipos no-O1/no-O139 han sido menos estudiadas y sus factores de virulencia aún se desconocen. En el presente estudio se realizó la genómica comparativa de 2 cepas de Vibrio cholerae no-O1, una no-O139 obtenidas directamente de bivalvos y 8 aislados clínicos de diferentes brotes del período 1991-2018 en Chile. Se utilizó la base de datos mgc.ac.cn/VFs, la cual contiene todos los factores de virulencia de varias especies del géneroVibrio : cholerae, fischeri, parahemolyticus y vulnificus. Se identificaron en promedio 142 genes en las cepas clínicas, con un rango entre 140-148. Las cepas ambientales tuvieron un promedio de 138 genes de virulencia, con un rango entre 130-143. Todas las cepas analizadas comparten 125 genes de virulencia. Entre éstos destacan los genes: hemolisina hlyA, familia msh relacionada con adhesión, familia eps relacionada a secreción, familia de toxinas rtx, entre otros. Aunque no encontramos nuevos genes de virulencia, por su estado de conservación y arreglo en el genoma, las cepas ambientales aisladas de bivalvos se podrían considerar como una amenaza a la salud pública mundial.

Beca Postdoctoral del CONACYT Apoyo movilización del INIFAP

309 Comparative Vitaminomics of Coxiella, from human pathogens to endosymbionts in ticks

Vitaminómica comparativa de Coxiella, de patógenos de humanos a endosimbiontes en garrapatas

Bernardo Sachman-Ruiz1, Víctor García2, Luis Lozano3. (1) Artropodología, CENID-SAI, INIFAP (2) Micología y Microbiología, Medicina, Universidad de Chile (3) Centro de Ciencias Genómicas, UNAM

Los genomas bacterianos son el reflejo de su compromiso evolutivo al estilo de vida: patogénico, vida libre, endosimbiótico, entre otros. Las rutas metabólicas para elaborar vitaminas son sumamente complejas. Las bacterias pueden compartir vitaminas con otros microorganismos o con sus hospederos. En este trabajo se determinó la presencia de genes biosintéticos de vitaminas del grupo B en especies bacterianas del género Coxiella, comparando entre cepas patógenas de C. burnettii y endosimbiontes de garrapatas Amblyomma americanum, Rhipicephalus sanguineus, R. turanicus y R. microplus. Los genomas de C. burnetti conservan un mayor número de genes involucrados en la producción de vitaminas con 38 en promedio, con una tendencia a organizarlos en operón, mientras que en las cepas endosimbiontes, algunos están dispersos en el cromosoma. Los árboles filogenéticos obtenidos con genes de la biosíntesis de B2, nos muestran un proceso acelerado de especiación en los genomas de los endosimbiontes. Observamos diferencias importantes entre los genomas, C. burnettiiconserva un sistema toxina-antitoxina codificado entre los genes ribD y ribE del operón de biosíntesis de riboflavina; los endosimbiontes de R. sanguineus y R. turanicus poseen una duplicación larga en un segmento genómico que incluye el set de genes de biosíntesis de vitamina B2; el endosimbionte de A. americanum perdió cuatro genes en la ruta de la B1, un gen en la B2, 3 en la B3 y 1 en la B5. La vitaminómica es un área de estudio que coadyuva a entender mejor la naturaleza de las especies bacterianas y su relación con su medio ambiente-hospedero.

Beca de Postdoctorado del CONACYT Apoyo a la Movilidad INIFAP

310 Morphological and genomic characterization of a cold active lactase-producing Antarctic bacteria

Caracterización morfológica y genómica de una bacteria antártica productora de lactasa activa en frío

Rodrigo Salazar2,1, Andrés Santos2,1, Kattia Núñez2,1, Leticia Barrientos2,1. (1) Laboratorio de Biología Molecular Aplicada, Centro de Excelencia en Medicina Traslacional, Universidad de La Frontera (2) Núcleo Científico y Tecnológico en Biorecursos (BIOREN), Universidad de La Frontera

Los hábitats antárticos representan un recurso importante de biodiversidad y, por lo tanto, de nuevos productos biológicos, tales como enzimas, proteínas, metabolitos secundarios y compuestos bioactivos, ya que varias adaptaciones extremofílicas pudieran estar presentes simultáneamente, lo que se refleja en la producción de diversas moléculas, que les permiten soportar las condiciones extremas de ese ambiente. El interés por estos compuestos microbianos ha ido en aumento ya que presentan propiedades físicas y químicas particulares a las encontradas en ambientes mesófilos. Bajo este concepto, la bioprospección de moléculas adaptadas al frío como las extremozimas representa un alto interés biotecnológico. Las β-galactosidasas son lactasas ampliamente utilizadas en la industria láctea para el proceso de deslactosado de la leche para las personas con intolerancia a la lactosa. El objetivo de este estudio fue describir la cepa antártica (Se8.10.12) productora de lactasa activa en frío. Primeramente, se realizó una caracterización morfológica mediante microscopía y pruebas bioquímicas. Luego, se realizó el análisis bioinformático mediante un ensamble híbrido utilizando datos de secuenciación obtenidos desde las tecnologías Illumina y Oxford Nanopore. Los resultados permitieron determinar que la cepa Se8.10.12 pertenece al género Rahnella, lo que coincide con los resultados de la caracterización bioquímica y morfológica. Esta cepa es poco común y nunca antes había sido descrita en suelo antártico. Además, los análisis corroboran la existencia de genes atribuibles a la producción de β-galactosidasa, confiriéndole un potencial interés biotecnológico.

Proyectos INI-4 UFRO-UAndes; DI19-0079; NXR17-0003

311 Fungal populations inside asthmatic residences in Havana, Cuba

Poblaciones fúngicas en el interior de residencias de asmáticos en La Habana, Cuba

Kenia Caridad Sánchez1, María Del Rocío Reyes Montes2, Michel Almaguer Chávez1, Sonia Rodríguez Davydenko1, Esperanza Duarte Escalante2, Teresa Irene Rojas Flores1. (1) Microbiología y Virología, Biología, Universidad de la Habana (2) Departamento de Microbiología y Parasitología, Unidad de Micología, Medicina, Universidad Nacional Autónoma de México

La exposición humana a hongos en el interior de locales se ha implicado en la etiología del asma, debido a la alergenicidad de los propágulos fúngicos y a que son fácilmente respirables. En este trabajo se caracterizaron las poblaciones fúngicas del interior de residencias de asmáticos en dos municipios de La Habana. Se estudiaron 30 residencias de dos municipios densamente poblados de la ciudad de La Habana, uno céntrico (Cerro) y otro periférico (Arroyo Naranjo). En cada casa se recolectaron e identificaron los hongos del aire, del polvo, así como de sustratos con evidencias visibles de crecimiento fúngico. Se calculó la concentración, densidad y frecuencia relativa de los hongos identificados. Las especies del género Aspergillus se caracterizaron a través de análisis filogenético. En el 33% de las residencias evaluadas se registró mayor recuento fúngico (UFC/m3) en el aire interior que en el exterior. Se identificaron 18 géneros fúngicos en el aire interior y 13 en el exterior, así como 9 en el polvo e igual número en paredes y techos. Aspergillus destacó por su frecuencia, seguido de Penicillium, Cladosporium y Curvularia, géneros considerados como alergénicos. Las especies A. heteromorphus y A. welwistschiae fueron las más frecuentes de su género. Las elevadas concentraciones de hongos en el aire interior de las residencias se correlacionaron con problemas en la ventilación, el estado constructivo y la frecuencia de limpieza.

312 Detection of the polyketide synthase gene (PKS) in actinomycetes of marine and terrestrial origin

Detección del gen de la policétido sintasa (PKS) en actinomicetos de origen marino y terrestre

Marilin Sánchez1, Junior Caro Castro2, Nadia Galindo Cabello 2, Jorge León Quispe2. (1) Departamento de Biología, Facultad de Ciencias Biológicas , Universidad Nacional Pedro Ruiz Gallo, Chiclayo- Perú (2) Departamento de Microbiología y Parasitología, Facultad de Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima- Perú

Introducción: Los actinomicetos son un grupo de bacterias que se conocen por su alta capacidad de síntesis de metabolitos secundarios tales como los antibióticos, los cuales derivan de los policétidos, que a su vez tienen su base genética en los genes PKS, por lo que su presencia en el genoma de dichas bacterias son un indicador indirecto de su potencial antimicrobiano. Objetivo: Determinar la presencia del gen policétido sintasa (PKS) en el ADN de actinomicetos marinos y terrestres.Materiales y métodos: Actinomicetos previamente evaluados como sintetizadores de sustancias antimicrobianas frente a bacterias, hongos y parásitos en el laboratorio de Ecología Microbiana de la Universidad Nacional Mayor de San Marcos, fueron reactivados en agar marino y agar avena. Luego de una caracterización morfológica y fisiológica, se sembraron en medios de propagación para la extracción de material genético con el kit comercial de purificación de ADN GeneJET Genomic DNA. El material genético fue amplificado por PCR utilizando primers específicos para el gen PKS y corroborado mediante electroforesis. Adicionalmente, se realizaron observaciones por microscopía electrónica de barrido y pruebas moleculares de identificación.Resultados: De un total de ocho actinomicetos evaluados, solo uno de ellos (AND-24, de origen terrestre) presentó el gen PKS, evidenciado por la banda de 700 pb en la electroforesis. Asimismo, esta cepa fue identificada como Streptomyces. Conclusión: Se corrobora la base genética de la actividad antimicrobiana del actinomiceto AND-24 por la presencia del gen PKS. Palabras clave: Actinomicetos, antimicrobiano, biología molecular, gen PKS.

Financiamiento: Vicerrectorado de Investigación y Posgrado (VRIP) – Universidad Nacional Mayor de San Marcos (Proyecto: Código, B18101951, RR N° 03202-R-18).

313 From endemic forests to the wine glass: structure of the fungal and bacterial diversity through the native sclerophyll vegetation, vines and wine in the Chilean Mediterranean Ecosystem

De bosques únicos a la copa de vino: estructuración de la diversidad de hongos y bacterias a través de la vegetación nativa esclerófila, vides y el vino en el ecosistema mediterráneo chileno

Roland Sanchez1, Olga Barbosa1, Andrea Silva1. (1) Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral De Chile (Sponsored by Olga Barbosa Prieto)

Los microorganismos regulan múltiples funciones que son importantes para sostener la agricultura. Debido al conflicto de uso de suelo que se origina entre la actividad productiva agrícola y la conservación de hábitats, resulta importante identificar cuales factores o prácticas asociadas a los ecosistemas naturales y el manejo agrícola mantienenla diversidad microbiana en agroecosistemas. Aquí usamos como modelo el Ecosistema Mediterráneo Chileno, parte de un Hotspot de biodiversidad, para evaluar el rol de la vegetación nativa esclerófila en la regulación de la diversidad microbiana asociada a la vid en viñedos del valle de Colchagua. La metodología consistió en colectar muestras de uvas durante 2 temporadas de cosecha con condiciones climáticas contrastantes, y caracterizar la diversidad de hongos y bacterias por medio de secuenciación de amplicones (16s, ITS2 y D2) para revelar su estructura comunitaria a través del paisaje y hasta el proceso de elaboración de vino. Los resultados muestran que uvas provenientes de viñedos circundados por una mayor cobertura de vegetación esclerófila evidenciaron una mayor riqueza de OTUs (~especies), uniformidad y diversidad filogenética fúngica. Del mismo modo, vinos elaborados con uvas provenientes de estos viñedos mostraron una menor abundancia relativa del hongo patógeno Botrytis. Estos resultados sugieren la vegetación nativa esclerófila provee beneficios a la industria vitivinícola chilena asociados a la mantención de la biodiversidad y el control biológico de plagas.

Beca CONICYT 21120897, Proyecto T7816110001 del Programa de Atracción e Inserción, Proyecto AFB170008 del Programa de Inversión Asociativa (PIA), Programa Vino, Cambio Climático y Biodiversidad, Instituto de Ecología & Biodiversidad

314 Revealing fungal richness of marine ecosystems and their biotechnological potential in Costa Rica

Revelando la riqueza fúngica de ecosistemas marinos y su potencial biotecnológico en Costa Rica

Stephanny Sánchez-Vargas1, Luis Vega-Corrales2, Stefany Solano-González1, Javier Alvarado-Mesén3. (1) Biotecnología, Ciencias Exactas y Naturales, Universidad Nacional (2) Laboratorio de Microbiología Marina, Ciencias Exactas y Naturales, Universidad Nacional (3) Laboratorio de Bioquímica y Biotecnología de Proteínas, Ciencias Exactas y Naturales, Universidad Nacional

Los hongos marinos cumplen un papel determinante en los ecosistemas acuáticos. Las condiciones ambientales de estos hábitats le confieren a los microorganismos características exclusivas que los hacen destacar sobre sus contrapartes terrestres. Esta singularidad los hace altamente atractivos por su capacidad de producir compuestos con aplicabilidad biotecnológica. Bajo este marco, la gran riqueza biológica y la favorecedora posición geográfica de Costa Rica, lo convierten en un lugar idóneo para el aislamiento de hongos marinos con potencial biotecnológico. Sin embargo, existe una falta significativa de informacion sobre esta diversidad. Actualmente, no existen registros recientes sobre la diversidad fúngica marina y mucho menos sobre su distribución en el país. Ante esta inherente necesidad, estudiamos la diversidad de hongos marinos presentes en ecosistemas de manglar y evaluamos su potencial biotecnológico en Costa Rica. A partir de sedimentos fangosos y arenosos del manglar de Puntarenas, se obtuvieron 25 aislamientos diferentes. Validamos un protocolo de muestreo y aislamiento de cepas y los resultados preliminares muestran que las cepas aisladas presentan variedad de morfologías pertenecientes al menos a los órdenes Hypocreales, Eurotiales y Capnodiales. La producción de metabolitos secundarios por parte de algunos aislamientos ha sido determinada. Proximamente evaluaremos la aplicación biotecnológica y actividades de estos metabolitos mediante la implementación de pruebas químicas y asignaremos la taxonomía a sus respectivos productores. Los resultados de este estudio, pionero en Costa Rica, para hongos aislados de manglar sienta las bases para futura bioprospección, optimización, producción y aplicación de metabolitos secundarios de hongos marinos en el país.

El desarrollo de esta investigación se realizó bajo el proyecto académico de la Universidad Nacional de Costa Rica, titulado: “Aislamiento y estudio de cepas fúngicas como potenciales productores de metabolitos secundarios de interés biotecnológico”.

315 Diversity of actinobacteria present in El Tatio soils by sequencing of the full-lenght 16S rRNA gene using nanopore technology

Diversidad de actinobacterias presentes en suelos de El Tatio mediante secuenciación del gen 16S ARNr completo empleando la tecnología de Nanoporos

Andres Santos4,1, Jaime Martinez-Urtaza2, Bernardita Valenzuela3, Pedro Zamorano3, Leticia Barrientos4,1. (1) Laboratorio de Biología Molecular Aplicada , Centro de Excelencia en Medicina Traslacional, Avenida Alemania 0458 Temuco, Universidad de La Frontera (2) The Centre for Environment, Fisheries and Aquaculture Science (CEFAS), The Nothe, Barrack Road, Weymouth, UK (3) Laboratorio de Microorganismos Extremófilos, Avenida Angamos 601, Antofagasta, Universidad de Antofagasta (4) Núcleo Científico y Tecnológico en Biorecursos (BIOREN) , Universidad de La Frontera, Avenida Francisco Salazar, 01145 Temuco, Universidad de La Frontera

Las condiciones ambientales extremas del campo de geiseres de El Tatio, probablemente, han favorecido la adaptación de grupos bacterianos de interés biotecnológico tales como las actinobacterias. Nuestro objetivo fue caracterizar la diversidad de actinobacterias presentes en suelos de El Tatio. Para ello, con el kit DNeasy PowerSoil (QIAGEN) se extrajo ADN de cinco muestras de suelos adyacentes a dos lagunas expuestas a actividad geotérmica. Luego, con el kit 16S Barcoding de Oxford Nanopore Technologies se amplificó el gen 16S ARNr y la secuenciación se llevó a cabo en la plataforma MinION. La asignación taxonómica se realizó con Centrifuge 10.3 usando la base de datos SILVA 132. Los análisis de diversidad se realizaron mediante iNEXT y Pavian 0.3. La predicción de funcionalidad se realizó con la herramienta METAGENassist. El phylum Actinobacteria fue el segundo más abundante en las muestras con 61183 (18,52%) secuencias asignadas. A nivel de Clase, Acidimicrobiia (55,32%), Actinobacteria (32,35%) y Thermeleophilia (7,53%) fueron las más abundantes, mientras que, a nivel de género fueron Streptomyces (22,1%), Mycobacterium (4,9%), Sva0996 marine group (4,4%), Corynebacterium (2,8%) y Microbacterium (2,2%). El índice de Shannon fue de 3,8 y 3,1 para los suelos adyacentes a la laguna A y B respectivamente. Los análisis de funcionalidad basados en taxonomía indican que predominan los mecanismos de deshalogenación, reducción de sulfatos y nitritos. Estos resultados pueden ayudar a direccionar estudios de bioprospección de actinobacterias en este ambiente, además, estos datos son los primeros obtenidos mediante secuenciación por nanoporos para El Tatio. Beca CONICYT ‒ Doctorado nacional ‒21171392; Universidad de La Frontera CD-FRO1204; Proyecto NXR17-0003; DIUFRO DI19-0079.

316 Microbial community structure in the subsurface seabed of the Gulf of California assessed by full-length 16S rRNA gene nanopore sequencing

Estructura de la comunidad microbiana en el lecho marino subsuperficial del Golfo de California evaluada mediante secuenciación por nanoporos del gen 16S completo

Andres Santos1,4, Nicola Coyle5, Ronny Van Aerle3, Leticia Barrientos4,1, Araxi Urrutia5, Jaime Urrutia-Fucugauchi 2, Ligia Pérez-Cruz 2, Jaime Martinez-Urtaza3. (1) Núcleo Científico y Tecnológico en Biorecursos (BIOREN), Universidad de La Frontera, Avenida Francisco Salazar, 01145 Temuco, Universidad de La Frontera (2) Laboratorio de Paleoceanografía y Paleoclimas, Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Coyoacan 04510 D.F., Mexico, Universidad Nacional Autónoma de México (3) The Centre for Environment, Fisheries and Aquaculture Science (CEFAS), The Nothe, Barrack Road, Weymouth, UK (4) Laboratorio de Biología Molecular Aplicada , Centro de Excelencia en Medicina Traslacional, Avenida Alemania 0458 Temuco, Universidad De La Frontera (5) Department of Biology and Biochemistry, The Milner Centre for Evolution, University of Bath, Bath, UK, University of Bath

Marine sediment cores are a fundamental source for information on seabed depositional history, environmental change and insights about the microbial life in these deep layers of the marine floor. We analyzed two sediment cores: one collected in the Alfonso Basin, in the Gulf of California, and a second sampled from a site at same latitude but on offshore the Pacific Ocean. Samples were collected along 50 cm of sediment core recording 500 years of depositions. Full-length 16S rRNA gene was amplified and sequenced on the MinION platform. Community analyses showed a decreasing pattern of diversity values in direct correlation with the layer depth. In addition, bacterial communities along each sediment cores were grouped in four clusters in function of layer depth. Beta diversity analyses did not show differences in taxonomic composition and superficial layer samples were the most similar between both sediment cores. In addition, samples were clustered in two main groups (superficial and depth). Sedimentary bacterial community were dominated by phylum Proteobacteria, Firmicutes and Actinobacteria while at genus level Desulfatiglans, Bacillus and Coxiella were the most abundant. Abundance of these genus consistently increased along depth of the sediment layers, most distinctive increasing was observed among the genus Desulfatiglans. Taxonomy based functional analyses showed that sulfate and nitrite reduction and ammonia oxidation mechanisms predominate in both sediment cores. This information represents a glimpse into the life in the sedimentary layers of oceans and provide unique information to understand basic biological strategies to survive under the particular conditions of these environments.

Beca CONICYT ‒ Doctorado nacional ‒21171392; Universidad de La Frontera CD-FRO1204; CEFAS internal Seedcorn funding; Academia Mexicana de Ciencias (AMC)-Newton International Collaboration Programme.

317 Bacteria or clay? A bayesian approach to the effects of glacier retreat on nanoflagellate bacterivory

¿Bacteria o arcilla? Un enfoque bayesiano a los efectos de la retracción glaciar en la bacterivoría de nanoflagelados.

Luca Schenone1, Esteban Balseiro1, Beatriz Modenutti1. (1) Laboratorio de Limnología, INIBIOMA (CONICET-UNCo)

El estudio de interacciones tróficas mediante modelos matemáticos, y su respuesta frente a variables ambientales, resulta un campo desafiante en la ecología microbiana. Diferentes enfoques han permitido separar y cuantificar esta complejidad basándose en teoría previa y experimentos que la validen. En este trabajo se modeló la bacterivoría de la comunidad de nanoflagelados en lagos glaciares del norte andino-patagónico, que reciben el ingreso de arcillas producto de la retracción glaciar. Se realizaron series de experimentos a campo con bacterias marcadas con fluorescencia (FLB): unos en un gradiente de concentración de arcillas manteniendo la luz constante y otros en condiciones de luz contrastantes. Los datos obtenidos se modelaron con sistemas de ecuaciones no lineales para representar el consumo de presas en función del tiempo, la concentración de arcillas glaciares y la luz. Los parámetros se estimaron mediante modelos jerárquicos bayesianos, que permitieron cuantificar el efecto de cada tratamiento teniendo en cuenta la estrategia nutricional de los nanoflagelados (heterotróficos y mixotróficos). Los resultados mostraron un efecto de interferencia por arcillas glaciares que reduce exponencialmente la bacterivoría tanto en flagelados heterotróficos como mixotróficos. Asimismo, para los flagelados mixotróficos se encontró una relación inversa entre la disponibilidad de luz y la bacterivoría. Debido a que la comunidad de los lagos estudiados estuvo dominada por mixótrofos, concluimos que las arcillas glaciares modulan la bacterivoría mediante interferencia y cambios en la disponibilidad de luz. De esta forma, la aproximación bayesiana resultó una herramienta útil para abordar el estudio de variables ambientales sobre el bucle microbiano planctónico.

CONICET y FONCyT. Trabajo enmarcado en el proyecto “Efecto del cambio climático en el incremento de nutrientes, el bucle microbiano y el plancton de ambientes acuáticos andino-patagónicos” PICT 2015-0418 dirigido por la Dra. Beatriz Modenutti.

318 Exploring thermophiles from an Antarctic volcano for potential application in oil industry

Exploración de termófilos de un volcán antártico para aplicación en la industria petrolera

Junia Schultz1, Isabella Campelo Vilardi Argentino1, Alexandre Soares Rosado1. (1) Laboratory of Molecular Microbial Ecology, Institute of Microbiology, Federal University of Rio de Janeiro

This study aimed to bioprospect and select bacteria from Deception Island, an active polar volcano in Antarctica, capable of degrading petroleum hydrocarbons and producing biosurfactants under thermophilic conditions. About 100 thermophilic bacteria were isolated from the Fumarole Bay and Whalers Bay sediments on Bushnell-Hass agar medium supplemented with 2% crude oil and incubated at 55 °C for 24-48h. To test the ability of the isolates to degrade oil and verify the most promising ones, they were submitted to the drop test on 24-well plate (55ºC-14 days). Also, it was performed biosurfactant production screening with the isolates: foam production test, hemolysis test, oil displacement test, drop collapse and emulsification test with crude oil and diesel. A total of 81 isolates tested showed growth in BH medium supplemented with crude oil and 25 isolates showed high degradation rate in 24-well plates, with visual difference significantly higher than the other isolates and negative control. In the biosurfactant assays, 14 of the 25 isolates presented positive results in the oil displacement test, 11 in the drop collapse, 5 isolates presented the best results in the emulsification test (50-100% crude oil and 50-60% diesel), and all the five presented halo in the hemolysis test. All isolates were identified as Geobacillus by sequencing the 16SrDNA and had their genomes sequenced. Comparative genomic analyzes are being performed to better understand the pathways involved in the degradation and production of biosurfactant under thermophilic conditions and to enhance applications in the petroleum industry.

National Council for Scientific and Technological Development (CNPq), the National Council for the Improvement of Higher Education (CAPES) and the Carlos Chagas Filho Foundation for Research Support of Rio de Janeiro State (FAPERJ).

319 Diversity, function and biogeography of the sea urchin Abatus sp. microbiota

Diversidad, función y biogeografía de la microbiota de los erizos de mar Abatus sp

Guillaume Schwob1, Julieta Orlando1, Léa Cabrol2, Elie Poulin1. (1) Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile (2) Mediterranean Institute of Oceanography (MIO) UMR 7294, Campus universitario de Luminy, Marseille

The Southern Ocean and Antarctica are brittle ecosystems in which the understanding of biogeographic patterns has become a major issue to predict the future distributions of organisms in response to global changes. Unlike the biogeography of macro-organisms, the biogeographic patterns of micro-organisms are still debated, particularly in the case of symbiotic microbes that could share an evolution history with their hosts. In that regard, the ongoing project « Genomics Antarctic Biodiversity » (GAB) aims to describe the holobiont genetic diversity among two sea urchin sister species belonging to the Abatus genus distributed along the Southern Ocean, and to investigate a possible co- evolution of the intestinal microbiota and the host. In this case study, gut tissue and gut content microbial composition of the sea urchin species Abatus cordatus and Abatus agassiizi, and their surrounding sediments, were surveyed in the Kerguelen Islands (French Southern and Antarctic Lands) and in the South Shetland Islands (Antarctica) by DNA metabarcording of 16S rDNA amplicons. Alpha and beta diversity analyses revealed distinct bacterial communities among the three micro-environments. Functional predictions of the gut microbiota showed relation to Kyoto Encyclopedia of Genes and Genomes (KEGG) categories in metabolisms of carbohydrates and lipids, transport and catabolism, and cell motility. Co-occurrence network analysis revealed Planctomycetes and Desulfococcus as potential keystone taxa influencing population structure in the gut microbiota. Finally, the micro-diversity within the OTU level was investigated to explore genetic structure of shared gut bacteria among the different Abatus populations, revealing evidence of biogeographic patterns.

CONICYT PIA ACT172065

320 The effect of the chinstrap penguin Pygoscelis( antarctica) colony on the diazotrophic bacterial community in Deception Island, Antarctica

El efecto de la colonia de pinguinos barbijos (Pygoscelis antarctica)sobre la comunidad de bacterias diazotróficas en Isla Decepción, Antártica

Diego Segura1, Jerónimo Cifuentes1, Wilson Castillo1, María Angélica Casanova2, Beatriz Díez1. (1) Laboratorio de Microbiología de Sistemas Extremos, Facultad de Ciencias Biológicas , Pontificia Universidad Católica de Chile (2) Núcleo de Estudios Ambiental, Facultad de Recursos Naturales, Universidad Católica de Temuco

El nitrógeno molecular (N2) es convertido en amoniaco (NH3) en un proceso llamado fijación de N2, mediante la acción de organismos diazotróficos. Estos organismos presentan los genes nif, los cuales codifican para la enzima nitrogenasa. El gen nifH es altamente conservado, por lo que es utilizado como marcador para estudiar la diversidad genética en diazótrofos. En muchos de estos organismos la actividad diazotrófica es inhibida en presencia de altas concentraciones de NH3.

En Antártica, los pingüinos transfieren al suelo cantidades significantes de nutrientes y contaminantes, influenciando sus propiedades fisicoquímicas, formando lo que se denomina “suelo ornitogénico”, rico en nitrógeno. De esta manera, los pingüinos a través de su contribución significativa al ingreso de nitrógeno combinado al ecosistema antártico son un componente que podría estar modulando la presencia de las poblaciones de organismos diazótrofos. En este trabajo, se analizó la diversidad y composición de la comunidad bacteriana-diazotrófica a través de análisis de genes 16S rRNA-nifH-DGGE y secuenciación masiva Illumina Mi-seq, para determinar el efecto de la contribución de N debido a colonias de pingüinos Pygoscelis antarticasobre estas comunidades en suelos de Isla Decepción. Nuestros resultados muestran una disminución de organismos diazotrófos influenciados por la presencia de la pinguinera, donde las cianobacterias diazotróficas fueron un componente importante en suelos con vegetación y menor influencia de las pinguineras.

Por efecto del cambio climático, el número de P. antartica en esta isla ha disminuido, lo cual puede tener efectos directos en la composición y estructura de las comunidades diazotróficas en estos suelos. FONDECYT n° 1181745

321 Construction of a “mutator” device via manipulation of the DNA replication machinery components of Streptomyces lividans TK24

Construcción de un dispositivo “mutador” mediante la manipulación de los componentes de la maquinaria de replicación del ADN de Streptomyces lividans TK24

Olga Sekurova1, Yi-Qian Sun2, Anna Stich1, Martin Zehl1, Tobias Busche3, Christian Rückert3, Jörn Kalinowski3, Sergey Zotchev1. (1) University of Vienna, Vienna, Austria (2) Norwegian University of Science and Technology, Trondheim, Norway (3) Universität Bielefeld, Bielefeld, Germany

In Escherichia coli, DNA replication fidelity is controlled by the exonuclease activity of the DnaQ representing epsilon subunit of DNA polymerase III (DNA PolIII), and mutations in DnaQ affecting this activity lead to a “mutator” phenotype. However, in Streptomyces lividans TK24 overexpression of various dnaQ mutants, or even complete deletions of dnaQ1 and dnaQ2 paralogues did not lead to increased spontaneous mutagenesis. Interestingly, dnaQ1 and dnaQ2 knockouts showed deficiency in the SOS response. These data suggested that S. lividans uses an alternative exonuclease activity to guarantee replication fidelity. Like inMycobacterium tuberculosis, such activity could be an intrinsic property of DnaE1 representing the alpha subunit of DNA PolIII. Eleven DnaE1 mutants were combinatorially assembled from synthetic parts and overexpressed inS. lividans. Recombinant strains overexpressing two of those mutants displayed markedly increased frequency of spontaneous mutagenesis, which was up to 1000 higher compared with the control. One of these “mutator” devices was combined in S. lividans with a previously assembled biosensor specific for coelimycin, which is not normally produced by the strain. Colonies giving positive biosensor signal appeared at a frequency of ca 10-4, while no such colonies could be detected in the control. 7 out of 8 positive colonies were found to produce coelimycin, confirming that the “mutator” device can be applied for chemical- and radiation-free mutagenesis in Streptomyces that can lead to activation of orphan biosynthetic gene clusters and discovery of novel bioactive secondary metabolites.

322 Chemo-prospecting of Streptomyces sp VB1. of the South Pacific: genomic and metabolic study for the search of new antimicrobial compounds

Quimio-prospección de Streptomyces sp VB1. del pacífico sur: Estudio metabólico y genómico para la búsqueda de nuevos compuestos antimicrobianos

Néstor Serna-Cardona1, Beatriz Cámara1. (1) Laboratorio de microbiologia molecular y biotecnología ambiental, Departamento de Química & Centro de Biotecnología DAL, Universidad Técnica Federico Santa María

The indiscriminate use of antibiotics has favoured the conditions for pathogenic microorganisms to be selected. The scientific community has highlighted the need to identify new bioactive molecules from new natural sources. Specifically, marine actinomycetes have aroused interest because they are an emerging source ofantibiotic compounds. Our group has worked in the bioprospecting of marine actinomycetes and their natural products, in this exploration we obtained a collection of around 30 strains of Streptomyces, in whichStreptomyce s sp. VB1, presented an important inhibitory activity in plate against Staphylococcus aureus (STAU). The evaluation of the antimicrobial activity from crude extracts obtained by OSMAC (One Strain Many Compounds) approach ofthis Streptomyces corroborated the observed in plates, inhibiting even strains of Methicillin-resistant Staphylococcus aureus (MRSA). Cultures supplemented with glucose and sucrose, presented higher inhibition. Analysis of the metabolic profiles of active fractions by liquid chromatography-high resolution mass spectrometry (LC-HRMS) allowed the identification of peptides such as globomycins and arilomycins; further anthracyclines and furanones, where several of them are not consigned in the dictionary of natural products (DPN). As an additional support to the search of new products, genome mining has allowed the identification of clusters of biosynthetic genes (BGCs) responsible for synthesis, finding that Streptomyces sp. VB1 has thirty BGCs, among which it was possible to identify a BGC possibly producing arilomycin and a type II PKS that may correspond to the synthesis of anthracyclines.

Financiamiento: Beca CONICYT de doctorado21181274, Fondecyt Regular N°1171555, proyecto Conicyt PIA ACT172128.

323 Effect of the application of a static magnetic field (CME) continuous type and pulse type in the microalgae Scenedesmus obliquus and Nannochloropsis gaditana

Efecto de la aplicación de un campo magnético estático (CME) tipo continuo y tipo pulso en las microalgas Scenedesmus obliquus y Nannochloropsis gaditana

Génesis Serrano1, Carol Miranda2, Alejandro Maureira2, Cristian Wulff1, Pablo Ferrada3, Manuel Zapata2, Mariella Rivas2. (1) Biomédico, Ciencias de la Salud, Universidad de Antofagasta (2) Laboratorio de Biotecnología Algal y Sustentabilidad, Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (3) Centro de Desarrollo Energético Antofagasta, Ingeniería, Universidad de Antofagasta (Sponsored by Laboratorio De Biotecnología Algal Y Sustentabilidad, Departamento De Biotecnología. Facultad De Ciencias Del Mar Y Recursos Biológicos, Universidad De Antofagasta.)

El campo magnético estático (CME) produce un efecto sobre sistemas biológicos donde el mecanismo de intercambio de información de un estado magnético (definido) genera respuestas a nivel celular sobre moléculas biológicas. En esta investigación se evaluó la influencia del CME de intensidad moderada sobre dos microalgas modelos: Scenedesmus obliquus y Nannochloropsis gaditana. Los cultivos de microalgas (3 réplicas) en fase exponencial fueron sometidos a estrés mediante un CME. Se diseñó un dispositivo compuesto por imanes de neodimio con intensidad moderada en 3 conformaciones Norte, Sur, Norte-Sur y un control sin exposición al campo magnético, se utilizaron dos métodos de exposición, continuo y pulso. En paralelo, se realizaron mediciones de los parámetros fisicoquímicos (pH y oxígeno disuelto), cinética, eficiencia fotosintética cada 24 horas por 5 días. En respuesta al estrés oxidativo producido por el CME, se evaluaron con agentes antioxidantes: superóxido dismutasa (SOD) y catalasa (CAT). Además se cuantificó la producción de metabolitos de interés, a través de cromatografía líquida de ultra alta eficiencia (UHPLC masa-masa). Finalmente, los análisis de datos fueron sometidos a análisis de varianza (ANOVA). El CME influye significativamente sobre la actividad enzimática, aumentando la SOD con el tratamiento continuo en disposición Norte y Sur para la microalga S. obliquus, en comparación con el control. Para la microalga N. gaditana, aumento en forma significativa la actividad de SOD con el tratamiento pulso en disposición Norte y Sur, en comparación con su control. El CME afecta la producción de metabolitos de interés como antioxidantes, carotenoides, pigmentos accesorios, entre otros. - Programa Semilleros de Investigación de la Universidad de Antofagasta, 2016.

- Beca “Fondo para el desarrollo en investigación científica y/o tecnologíca de actividades de titulación de pregrado”, Universidad de Antofagasta.

324 Acetic acid bacteria from the gut microbiota of pest bean weevils

Bacterias del ácido acético de la microbiota intestinal de los gorgojos del frijol

Luis Eduardo Servín-Garcidueñas1, Esperanza Martínez-Romero2. (1) Laboratorio de Microbiómica, Escuela Nacional de Estudios Superiores Unidad Morelia, Universidad Nacional Autónoma de México (2) Laboratorio de Microbiología Ambiental y Simbiótica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (Sponsored by Universidad Nacional Autónoma De México)

Weevils are important pests of stored grain legumes that feed and reproduce on dried seeds (Tuda, 2007) and are cosmopolitan. The neotropical genus Acanthoscelides Schilsky comprises a diverse group of weevils some specialized on Phaseolus seeds. Weevils were field-collected from inside wild Phaseolus vulgaris seeds and pods. The guts of adult bean weevils, Acanthoscelides obtectus (Coleoptera: Chrysomelidae, Bruchinae) were screened to detect midgut bacteria. Future usage of bacterial symbionts as biological control agents could be an alternative to pesticides. Bacterial identification was achieved by amplifying and sequencing 16S rRNA genes and performing phylogenetic analysis. Preliminary results revealed phylotypes related to Massilia, Propionibacterium as well as Bradyrhizobium. Endophytes of P. vulgaris seeds had been described (Lopez-Lopez et al, 2010) and will allow us to test the transmission of seed bacteria to beetles guts. Several insects with sugar‐based diets or phloem sap insects have been recently shown to host symbiotic acetic acid bacteria (Crotti et al., 2010). We identified the presence of acetic acid bacteria of the genus Asaia in the midguts of Acanthoscelides. Notably, Asaia has been found stably associated with malaria transmitting mosquitoes (Favia et al., 2007). Interestingly, a phylotype with only 91% sequence identity to sequences from described acetic acid bacteria was identified and may represent a novel symbiont of bean weevils. This study furthers spans the inventory of insects naturally associated with acetic acid bacteria.

This research was supported by grants from PAPIIT-UNAM (IA208019).

325 Joining extreme enviroments: Cyanobacterial diversity in Salar de Aguas Calientes and Salar de Tara

Uniendo ambientes extremos: Diversidad de Cianobacterias en Salar de Aguas Calientes y Salar de Tara

Cuellar Shelsy 1,2, Cristina Dorador1,2,3. (1) Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta (2) Laboratorio de Complejidad Microbiana y Ecología Funcional , Instituto Antofagasta, Universidad de Antofagasta (3) (CeBiB), Santiago de Chile (CL), Centre for Biotechnology and Bioengineering

El altiplano del norte de Chile es heterogéneo y se caracteriza por presentar condiciones ambientales extremas: altos niveles de radiación UV, amplias fluctuaciones de temperaturas, balance hídrico negativo y concentraciones de sales variables. A pesar de estas características extremas, estos sectores presentan una alta diversidad y variabilidad espacial microbiana. Las cianobacterias son microorganismos que tienen un importante rol en el ecosistema como productores primarios y en la formación de tapetes microbianos. Sin embargo, el conocimiento sobre su diversidad en ambientes extremos es aún insuficiente. En el Altiplano de la región de Antofagasta, sobre los 4000 msnm, se encuentra el Salar de Aguas Calientes (SAC) y Salar de Tara (ST), ubicados en la Reserva Nacional Los Flamencos, ambos sistemas son sitios de alta importancia ecológica y ambiental, sin embargo, poco se conoce sobre su diversidad microbiana. En este trabajo se analizó la estructura de la comunidad de cianobacterias en muestras de tapetes microbianos previamente colectados en diferentes sitios y muestras del SAC y ST. Los análisis se realizaron mediante librerías de clones del gen 16S rRNA y electroforesis en gel con gradiente desnaturalizante (DGGE). Los clones obtenidos fueron clasificados y los géneros más frecuentes corresponden a Gleiterinema, Nostoc, Anabaena, Dolichospermum y Phormidium. Las secuencias se encuentran relacionadas con filotipos recuperados desde distintos ambientes fríos (biósfera fría), lo que podría dar indicios sobre posibles conexiones con cianobacterias presentes en otros hábitats extremos.

Fondecyt 1181773, CeBiB FB001

326 Phytoplankton diversity in the photic zone from the oceanic region of the gulf of Mexico by metagenomic analysis

Diversidad del fitoplancton en la zona fótica de la región oceánica del golfo de México a partir de análisis metagenómico

Karla Sidón Ceseña1, María Asunción Lago Lestón1, Jennifers Chong Robles1, Dante Alberto Magdaleno-Moncayo1. (1) MICROBIOLOGIA, CICESE

La composición del fitoplancton es muy sensible a los cambios ambientales en la columna de agua. En el Golfo de México (GoM) la mayor variabilidad en la región oceánica la determina la intensidad de intrusión del flujo de la corriente de Lazo, que se intensifica en verano y llena el GoM con aguas muy oligotróficas, procedentes del mar Caribe. Por otro lado, los remolinos de mesoescala crean condiciones favorables para la productividad biológica dentro del GoM. El objetivo de este trabajo fue determinar la estructura y variabilidad del fitoplancton de aguas oceánicas del GoM mediante secuenciación masiva. Se obtuvo ADN de 72 muestras de las profundidades de superficie y del máximo de fluorescencia procedentes de las campañas oceanográficas del proyecto CIGoM: XIXIMI-4, XIXIMI-5 y XIXIMI-6, realizadas en los veranos del 2015, 2016 y 2017 respectivamente. Se amplificó la región V9 del gen ribosomal 18S, se secuenció y las secuencias se analizaron con QIIME 2 utilizando la base de datos PR2 para la asignación taxónomica.Los resultados mostraron que el micro fitoplancton dominaba las aguas superficiales con las familias como Gymnodiniales, Prorocentrales y Peridiniales aportando el 60-80% de la abundancia total. En cambio, el máximo de fluorescencia, fue dominando por el nano y picoplancton con las familias Syndiniaceae (20- 50%) seguida de Pelagophycea (10-30%) y Primnesiophyceae (10-20%), con abuncias variables dependiendo de la estación. Este es el primer estudio sobre la diversidad, distribución y variabilidad anual del fitoplancton en la región de aguas oceánicas mexicanas del GoM utilizando una aproximación metagenómica.

327 Arbuscular Mycorrhizal Fungi differ in their ability to produce glomalin in culture pots

Los hongos micorrízicos arbusculares difieren en su capacidad para producir glomalina en macetas de cultivo

Cleudison Gabriel Nascimento Silva1, Cristiane Figueira Silva2, Candido Barreto Novais2, Eliane Maria Ribeiro Silva3, Orivaldo José Saggin Júnior3, Ederson Da Conceição Jesus3. (1) Microbiologia Agrícola, Instituto de Biologia, Universidade Federal de Lavras, UFLA (2) Ciências Ambientais e Florestais, Instituto de Florestas, Universidade Federal Rural do Rio de Janeiro, UFRRJ (3) Embrapa Agrobiologia

Glomalin is a glycoprotein produced by arbuscular mycorrhizal fungi (AMF). This protein contributes greatly to carbon storage and soil aggregation. AMF species differ in the length and structure of their extraradical mycelia, which may reflect on differences in the deposition of glomalin in the soil. In this sense, the objective of this work was to evaluate the levels of glomalin related soil protein (GRSP) in culture pots of four species of AMF, Acaulospora foveata, Gigaspora candida, Glomus formosanum, and Scutellospora pellucida. The fungi belong to the AMF Collection of Embrapa Agrobiologia and were cultivated for 8 months in a greenhouse usingUrochloa decumbens as the host plant. Ten samples of 1 g of soil each were collected individually and the GRSP fractions (Easily extractable (EE-GRSP) and Total GRSP (T-GRSP)) were evaluated. Both fractions were extracted separately with sodium citrate and quantified by the Bradford method using bovine serum albumin standard. The data were submitted to an analysis of variance and Scott-Knott mean test (p <0.05). For both fractions (EE-GRSP and T-GRSP), it was verified that A. foveata contributed with higher levels of this protein if compared to the species S. pellucida, G. candida and G. formosanum. Thus, it can be inferred that A. foveata is more promising for the production of glomalin related soil protein in soil cultivated with U. decumbens under greenhouse conditions. Key-words: Arbuscular mycorrhizal fungi, glycoprotein, yield.

Funding: FAPERJ, CNPq e Capes.

328 Microbial community structure from benthic and bottom water off Valparaíso, Chile

Estructura de comunidades microbianas bentónicas y de agua de fondo frente a Valparaíso, Chile

Daniela Roccio Silva1. (1) viña del mar, Biología, Pontificia Universidad Católica de Valparaíso

La zona costera de Valparaíso (32°9´S, 71°6´W) está influenciada por condiciones oceanográficas como surgencia, que aporta aguas ricas en nutrientes que estimulan la producción primaria y aguas pobres en oxígeno (ZMO). Además, esta zona se caracteriza por la presencia del Río Aconcagua que aporta partículas y materia orgánica. En este estudio se determinó la composición de bacterias y arqueas bentónicas y del agua de fondo mediante la secuenciación masiva del gen 16S rRNA en muestras de una estación ubicada en el veril de 100 m de profundidad como parte de la Serie Oceanográfica Agua y Sedimento frente a Concón, realizada los meses de enero, abril, agosto y diciembre de 2015). Los resultados indican una mayor riqueza y diversidad asociada al sedimento en comparación con el agua (Número Otus= 439 versus 382 y H`=3,639 versus 2,687, respectivamente). En el sedimento, los taxa de arqueas más representativos fueronEuryarchaeta (65%) y Thaumarchaeota (57%)y de bacterias fueron Proteobacterias (>47%), Chloroflexi (>10%), Planctomycetes (>10%), mientras que en el agua fue Euryarchaeta, seguido del grupo Thaumarchaeota en cuanto a arqueas y Proteobacterias (>42%), Nitrospina (9-22%), Bacteroidetes (7-13%), Marinimicrobia (SAR406) (13-16%) en cuanto a bacterias. La estructura comunitaria presentó cambios vinculados con la presencia de la ZMO y el potencial efecto de ENSO evidenciado durante comienzos del año 2015, lo cual influyó en la físicoquímica del agua y el sedimento, evidenciada por variables como Redox, oxígeno disuelto, materia orgánica.

Verónica Molina Fondecyt 1171324

329 Permafrost Antarctic fungi and your potential for virulence factors in vitro

Thamar Holanda Silva1, Eldon Carlos Queres Gomes1, Luiz Henrique Rosa1. (1) Microbiology, Universidade Federal de Minas Gerais - UFMG

Concerns about global warming are closely linked to rising levels of the ocean and their consequences. However, the melting of the permafrost - soils that are permanently frozen for at least two consecutive years - also raises concerns about being able to contain cells, propagules and genetic material older of the planet, allowing the activation of fungi that, until then, were only in the inactive form. This work aimed to isolate, identify and characterize thein vitro virulence potential of permafrost fungi from different islands (King George, Robert, Deception and Livingston) in the Antarctic Peninsula. For isolation, DRBC, DG18, Minimum Medium and Sabouraud culture media were incubated at 37 ° C (to simulate body temperature) and the identification was performed through the ITS region. Growth in different pH ranges was performed in YM medium with pH 4 (vaginal pH), 7 (blood pH) and 9 (intestinal pH); the hemolytic activity (ability to break red blood cells for iron uptake) in blood agar and the production of hydrolytic enzymes (proteinase) in ASB agar medium, all at 37 °C for 7 days. Of the 48 isolates obtained, the following taxa were identified: Aspergillus hiratsukae, Aspergillus thermomutatus, Montagnula sp., Penicillium chrysogenum, Penicillium mononematosum, Penicillium rubens and Rhodotorula mucilaginosa. All isolates were able to grow at all pH ranges tested, produce proteinase enzymes and create halo hemolysis in blood agar. These in vitro results show that these fungi have virulence factors and raise great concern about their possible activation in the face of global warming.

CAPES, CNPq

330 Analysis of possible new species of the genus Glarea from the Antarctic Peninsula

Análisis de posibles nuevas especies del género Glarea de la península antártica

Thamar Holanda Silva1, Eldon Carlos Queres Gomes1, Isabel Martins Sabino Alves1, Luiz Henrique Rosa1. (1) Microbiology, Universidade Federal de Minas Gerais - UFMG

Antarctica is a unique and differentiated continent with respect to its environmental characteristics. Microorganisms present in this environment are endemic and/or adapted and present differential metabolic pathways necessary to adapt to the extreme conditions of the region. Samples of rocks, soil and permafrost were collected during five Brazilian expeditions in different islands of Antarctica, providing the isolation of seven isolates of the genus Glarea, which are deposited in the collection of Cultures of microorganisms and Cells of the Federal University of Minas Gerais (UFMGCB 10149, 10271, 10521, 10540, 14083, 14113, 14330). Taxonomic analyzes were performed through the ITS region. The optimum temperature test was performed in BDA medium (5 to 30ºC). Micro and macro-morphological analyzes were performed in BDA, YME and FB media, at 23 ºC, 12 h of photoperiod, 21 days. All isolates were able to grow between 5 and 15 °C. The micro and macro-morphological characteristics observed showed significant differences in the morphology between the UFMGCB isolates and the only specie described so far for the genus, G. lozoyensis. The isolate UFMGCB 14330 was the one that most resembled the species described, because it possesses polyblastic conidiogenesis. Taken together, such characteristics may be indicative of the presence of individuals of a new species. The major characteristic of this anamorph genus is the ability to produce pneumocandin B0, showing Antarctica not only as a potential source of new species but also as a source of fungi with promising potential in the production of metabolites of great medical interest.

CAPES, CNPq

331 Construction of bacterial Bi-Stable and Coupled Systems

Construcción de Sistemas Bacterianos Bi-estables y Acoplados

Kevin Simpson1, Janneke Noorlag2, Juan Keymer2,3, Fernán Federici1. (1) Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Fondo de Desarrollo de Áreas Prioritarias, Center for Genome Regulation, and Millennium Institute for Integrative Biology (iBio) (2) Departamento de Ecología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile (3) Departamento de Física, Facultad de Ciencias Físicas, Pontificia Universidad Católica de Chile

Deciphering the mechanisms underpinning cellular states distributions in bacterial colonies and biofilms is a long- standing challenge in Biology. Understanding how macroscopic order arises from microscopic rules and local interactions in large systems is a thoroughly studied problem in Physics. Pattern formation could also be regarded as the emergence of spatially-organized cellular states based on local cell-cell coupling. However, this type of mechanisms, such as ecological interactions or metabolic syntrophic exchanges, are difficult to study on whole systems. Here, we apply theoretical models from statistical physics and spatial biology to understand the emergence of global cellular state distributions from artificial cell-to-cell signaling and synthetic gene networks. We constructed synthetic bacterial systems that exhibit bi-stability and coupling between cellular states using acyl-homoserine lactone molecules from orthogonal quorum-sensing systems. In these synthetic minimal systems, each cell has the possibility of adopting one of two cellular states, and the adoption of a state is influenced by and influences the state of neighboring cells. Using a plate reader and a microfluidic device called the Mother Machine we showed that the systems are bi-stable and that the cellular states are coupled together at population and single-cell level. These systems will allow us to study the establishment and maintenance of cellular-state patterns during the growth of large populations of bacterial cells, and testing whether the coupling between cellular states facilitates the global pattern formation in multicellular systems. A better understanding of these processes could be instrumental in the development of biomaterials, artificial consortia, and tissue engineering.

Beca de Doctorado Nacional CONICYT 2016 (21160554)

332 Soil microbial community composition under organic and conventional management coffee systems in Costa Rica

Composición de la comunidad microbiana del suelo bajo un sistema de manejo orgánico y convencional de café en Costa Rica

Gabriela Montes De Oca-Vásquez1, Jordan Villalobos-Solís2, Frank Solano-Campos2. (1) National Center for High Technology, National Nanotechnology Laboratory (2) Escuela de Ciencias Biológicas, Ciencias Exactas y Naturales, Universidad Nacional

Microbial communities are indispensable to support soil ecosystem functions and are sensitive to agricultural management strategies. However, the effects of agricultural management on soil microbiome are complex, furthermore little is known about the soil microbial community composition in coffee under organic (OS) and conventional (CS) management systems in Costa Rica. Here we report on the soil microbiome of two coffee plots under different agricultural management using a combination of high-throughput short- and long-read sequencing. Genomic DNA was isolated from soil (0-10 cm) with a FastDNA Spin Kit and the MM400 bead beater. Amplicon libraries were prepared and sequenced with Illumina MiSeq (V3-V4) and Pacific Biosciences RSII (full 16S). USEARCH recommended pipeline was used to process raw reads, OTU clustering, generate OTU tables and perform diversity analysis. Taxonomic assignment was done with VSEARCH and SILVA v123 16S rRNA database. Clustering at 97% similarity threshold yielded 19 and 60 OTUs with total relative abundance greater than 0.5% from MiSeq and RSII platforms, respectively. Overall, Proteobacteria (up to 46.0% of the sequences), Chloroflexi (up to 21%)and Acidobacteria (up to 39.6%) were the most-abundant phyla, while Bradyrhizobium (up to 9.8%) and Acidibacter (up to 6.7%) were the most-abundant genera, with a significant number of sequences unassigned at the genus level (up to 82.1%). The richness and Shannon-Wiener index were higher in OS than in CS with both sequencing technologies, however not significantly different. Together, our work provides new insights into the microbial diversity in coffee- cultivated soils.

Universidad Nacional, FIDA project No. 0027-17.

333 Biodiversity characterization in Diamante lake (4570 m a.s.l., Argentina)

Caracterización de la biodiversidad en laguna Diamante (4570 m s.n.m., Argentina)

Mariana Noelia Soria1, Tatiana Stepanenko1, Agustina Lencina2, María Eugenia Farías1. (1) San miguel de Tucuman, Planta Piloto de Procesos Industriales Microbiológicos (PROIMI-CONICET) (2) Catamarca, Centro de investigación y transferencia de Catamarca (CITCA-CONICET)

Diamante lake, placed inside the crater of Galan supervolcano at 4589 m asl, is one of the most extreme environments in the world due to its high alkalinity (pH 11) and high arsenic concentrations 232 mgL-1. Under such conditions, red haloarchaea (Euryarchaeota phylum) biofilms develop at the bottom of calcium carbonate rocks (Rascovan et al., 2016). The hydrological mixing zones in the north and south of the lake owed to freshwater inputs from wetlands that result in a variation of the water physicochemical characteristics along this lake, especially change in salinity (60 - 104,6ppt). In this work, we studied how these environmental variations influence Diamante lake biodiversity. Biofilm and sediment samples from three different points of the lake: north (3), south (2) and east (1) were analyzed by RNAr 16S gene sequencing using the QIIME software. Higher diversity in sediment than in biofilms samples have been found in the three points studied. Sediments from the most saline zone (1) were dominated by Euryarchaeota, Firmicutes were found in the mixing zone (2) and the area with the lowest conductivity (3) (freshwater) was dominated by Cyanobacteria. While, biofilms only observed in points 1 and 2, were dominated by Euryarchaeota. The absence of biofilms in point 3 is probably due to the low salinity that inhibits the growth of halophilic organisms, like haloarchaea. These results suggest that salinity variation (or other covarying parameters) of the water surrounding the Diamante lake ecosystem has a critical influence in the structure of this microbial community.

334 Evaluation of microbial resistance from water channels of São Vicente Municipality (SP)

Evaluación de la resistencia microbiana de canales de agua de la Municipalidad de San Vicente (SP)

José Augusto Souza1, Mirella Massonetto2, Vanessa Da Costa Andrade2, Roberta Merguizo3, Ana Julia Fernandes Cardoso Oliveira1. (1) Micromar, Bioscience Institute, UNESP Litoral Paulista (2) UNESP Rio Claro (3) Micromar, UNESP Litoral Paulista, UNESP Litoral Paulista

The disordered occupation of dike areas in São Vicente municipality (São Paulo State, Brazil) leads to the improper discharge of domestic effluents, without any previous treatment. The discharge of sewage results in contamination of adjacent water bodies, especially during the rainy seasons. Some pathogens, like Escherichia coli, are commonly detected on areas contaminated by effluents, especially domestic sewage. The use of antibiotics by residents of these areas, favors the appearance of resistant bacteria that may act as resistome in the environment, being a serious risk to public health. This study aimed to verify and monitor the antibiotic resistance inE. coli on the water channels from insular area from São Vicente, during one year. E. coli were isolated in mTEC Agar, by Membrane Filter Technique. Positive strains (urea confirmatory test) were isolated in MacConkey Agar. Disc-diffusion test was performed as BrCAST guidelines and the following antibiotics were used: amoxicillin, amoxicillin+clavulanic acid, fosfomycin, amikacin, tetracycline, imipenem, ciprofloxacin, cefuroxime and sulfamethoxazole/trimethoprim. The results showed that the bacteria present in the water have a wide resistance to different antibiotics, being resistant to some antibiotics (e.g. cefuroxime 85%), and other hand, were susceptible to others, such as imipenem (75%). When compared the both seasons, winter presented a higher sensibility (51,9%) than during the summer (33,8%). Thus, it is extremely necessary to implement public sanitation policies for this area, in order to reduce the contamination that is spreading throughout the entire estuarine complex of São Vicente.

335 Study of the potential anaerobic degradation of hydrocarbons in the application of Natural Recovery Monitored of contaminated sediments of freshwater courses

Estudio de la degradación anaeróbica potencial de hidrocarburos en la aplicación de Recuperación Natural Monitoreada de sedimentos contaminados de cursos de agua dulce

Viviana Ayelén Starevich1, Laura Madueño1, Irma Susana Morelli2. (1) Laboratorio de remediación de sitios contaminados con hidrocarburos , CINDEFI CONICET- UNLP (2) Laboratorio de remediación de sitios contaminados con hidrocarburos , CINDEFI, CIC-PBA

La Recuperación Natural Monitoreada (RNM) como estrategia de remediación, aprovecha los procesos fisicoquímicos que ocurren en el ecosistema y las capacidades naturales de la población microbiana autóctona de degradar los contaminantes. Evidenciar ese potencial degradador es indispensable en el diagnóstico y monitoreo. El objetivo de este trabajo fue estudiar el potencial degradador de sedimentos anóxicos con distinta historia de impacto ambiental, mediante la predicción, detección y cuantificación de los genes biomarcadores bssA (bencilsuccinato sintasa) y bamA (6- oxociclohex-1-ene-1-carbonilCoA hidrolasa), vinculados con la degradación anaeróbica de hidrocarburos aromáticos. A partir de tres sitios D19, C21 y O1, se extrajo ADN de 16 horizontes y se secuenció la región V4 del gen 16s rRNA mediante Illumina-Miseq. Se detectó in silico (software PICRUSt) la presencia de los genes bssA y bamA en la mayoría de los horizontes superficiales de los tres sitios, y de bamA en algunos profundos. Mediante qPCR se cuantificaron dichos genes funcionales y las eubacterias totales (gen 16s rRNA). En concordancia con lo predicho in silico, los resultados de qPCR mostraron que el número de secuencias del gen bamA fue mayor que bssA en la mayoría de los horizontes. Al analizar la relación gen funcional/gen 16S rRNA se observó en la muestra O1 un incremento de número de copias del gen bamA con la profundidad y no con la concentración de hidrocarburos. La predicción funcional sitio específica permitió optimizar la selección y cuantificación de genes funcionales, que evidenciaron la capacidad degradadora anaeróbica potencial de hidrocarburos en los sitios afectados.

336 Characterization of biological crust cyanobacteria from Coquimbo drylands

Caracterización de cianobacterias de costras biológicas de la región de Coquimbo

Christopher Concha2, Karen Godoy1, Lorgio Aguilera1, Claudia Barraza-Cepeda1, Cristian Ibañez1, Karina Stucken2. (1) Departamento de Biología, Facultad de Ciencias, Universidad de La Serena (2) Departamento de Ingeniería en Alimentos, Facultad de Ingeniería, Universidad de La Serena

Desertification affects 1,5 billion people globally. In Coquimbo, an important part of soil degradation is given by soil erosion; in fact, Coquimbo is the most desertification-threatened region in Chile, where 84% of its soils are eroded. Soil rehabilitation by biological soil crusts (biocrusts) has been considered as a promising but still underexplored alternative to decrease desertification processes. Biocrusts are complex soil surface communities of cyanobacteria, mosses, lichens, and heterotrophs held together by cyanobacteria. Cyanobacteria play important roles in biocrust formation and in their ecological services. Filamentous and N2-fixing species stabilize the soil serving as a scaffold for successional colonizers and contribute to N2-fixation, respectively. With the aim to identify and characterize the cyanobacterial diversity present in biological soil crusts from the Coquimbo region drylands, we sampled 6 sites differing in erosion levels in a latitudinal gradient within the Coquimbo region. All sites shared the presence of a black and rugose crust. Most sites contained consolidated biocrusts, except in the highly eroded La Higuera site. Biocrust coverage was low in all sites, with an average biomass between 0.71 to 12.9 μg chl a g-1 soil in La Higuera. This shows that photosynthetic microorganisms exist in La Higuera soils, although biocrust consolidation is low. Morphological classification identified mostly Nostocalean (Nostoc spp. and Tolypothrix spp.) and Oscillatorean cyanobacteria. Further functional (N2-fixation, scytonemin production) and phylogenetic characterization of cyanobacterial isolates and the estimation of total microbial diversity, will identify the diversity of biocrust microorganisms and their ecosystemic functions in semiarid zones in Chile.

KS acknowledges the financial support of Conicyt through the project Fondecyt 11170842 and DIDULS/ULS, through the project PR17122/010201020913

337 Analysis of mobile Genetic elements in a latitudinal and longitudinal ocean gradient

Análisis de elementos genéticos móviles en un gradiente latitudinal y longitudinal a través de los océanos

Javier Tamayo-Leiva1,2, Beatriz Díez1,2. (1) Department of Molecular Genetics and Microbiology, Pontificia Universidad Católica de Chile (2) Center for Climate and Resilience Research (CR)2, Universidad de Chile

Marine microbial communities are highly dynamic systems, where microbes interact actively. Community dynamic is influenced by water mass circulation, migrations and anthropogenic activity, processes that allow the dispersal of microorganisms and genes through the oceans. However, genetic/genes mobility is mainly associated to horizontal gene transfer between organisms from a same location, through transduction, transformation or conjugation. The study of the mobility of genes through the oceans becomes relevant to understand the real contribution of horizontal gene transfer to the genetic diversity of the marine microbial community. The aim of this work is to identify and determine the diversemobile genetic elements and genes they mobilize to understand genetic diversity in marine microbial communities geographical separated. Through a bioinformatic approach, we analyzed relaxases and VirD4-like predicted proteins as markers for the identification of mobile genetic elements from 45 TARA Ocean metagenomes, using a classification based on their ability to be transferred. The results from the 45 TARA Ocean metagenomes suggest that, although there are dispersion events that homogenize genes through the oceans, many of the genes that are carried in mobile genetic elements are widely distributed among the oceans. Factors such as taxonomy and environmental conditions determine which genes are mediating the mobility of genetic elements on each local marine microbial community whilst common genes mobilized across oceans are carried by different mobile genetic elements, due to geographical factors which play a major role into the distribution of these mobile genetic elements across the oceans.

338 Characterization of microbial diversity associated with the production and preservation of gypsum microbialites from Salar Pajonales, northern Chile

Caracterización de la diversidad microbiana asociada con la producción y preservación de microbialitos de yeso, Salar Pajonales, Chile

Cinthya Tebes1, Constanza Rodriguez2, Cecilia Demergasso2, Guillermo Chong2, Nancy Hinman 2, Victor Parro3, Eduardo Castro-Callar4, Nathalie Cabrol5. (1) Departamento de Geología, Doctorado en Ciencias mención Geología, Universidad Católica del Norte (2) Universidad Católica del Norte (3) Astrobiology Center, España (4) Center for Bioinformatics & Integrative Biology (5) Carl Sagan Center, SETI, NASA

In the Andean Southeast area of Antofagasta, Salar Pajonales (SP) is one potential site for studying biotic and abiotic gypsum precipitation. Gypsum results from organ-mineralization and can exhibit distinctive features as biomineral. We are working with gypsum microbialites forming in brines with high concentrations of Ca (598-12300 ppm) and SO4 ions (480-2860 ppm) and their evolution colonized by living microorganisms up to microfossils. However, the microbial role in the gypsum precipitation and in the evolution of gypsum structure needs clarification. Our objective is to characterize the microbial communities in forming and preserved gypsum structures. Differential hydrochemistry was registered for abiotically/biotically gypsum precipitation. Microbialites were classified according to morphology, humidity, texture, mineralogy, microscopy, lipids-biomarkers, and microbial diversity. Today, microbialites are forming in brines in the SP’s center where significantly gypsum is oversaturated. Preserved outcrops are in the southeast part of the salar. XRD and XRF analyses showed gypsum crystals in both microbialites. The biogeochemistry/salinity and gypsum- morphology/relative humidity are important factors for differencing microbial diversity in brines and microbialites, respectively. The predominant phyla in the system were Cyanobacteria, Proteobacteria, and Bacteroidetes. The predominance of Dactyloccocopsis in forming-structures could play some role in gypsum precipitation. Conversely, Chroococcidiopsis found in preserved-domes is consistent with their adaptation to the surface mineral refuge that favors photoautotrophy. None of microorganisms identified in forming-microbialites was seen in the preserved ones. Whether preserved microbialites at SP grew similarly than today, the extant microorganisms should be the product of a re-colonization process rather than microbial remains involved in their origin.

339 Zygosaccharomyces as a new symbiont of the brood cell of stingless bees

Zygosaccharomyces como un nuevo simbionte de la célula de cría de abejas sin aguijón

Gabriela Toninato De Paula1, Weilan Gomes Da Paixão Melo1, Camila Raquel Paludo1, Mônica Tallarico Pupo1. (1) Department of Pharmaceutical Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo

A symbiotic interaction between the stingless bee Scaptotrigona depilis and the fungus Zygosaccharomyces sp. has been recently described. The fungus grows inside the brood cell and is eaten by the larvae, providing steroidal precursors for the developing bee to complete the metamorphic process.The objective of this study is to verify if this fungus-food symbiont is present in other species of stingless bees, as well as fungal steroidal content. Samples were obtained from the brood cell of 18 species of stingless bees, and 26S rRNA sequencing confirmed the presence of Zygosaccharomyces in seven species. It was also possible to obtain Zygosaccharomyces from other colony sites, such as honey, pollen, adult insects and scrap. Fungal cell analyses by fluorescence microscopy showed that all Zygosaccharomyces lineages are able to accumulate lipids in their cytoplasm. In addition, strains isolated from brood cells are able to form pseudohyphae whereas those isolated from other parts of the colony show only spherical and/or ovoid cells. Phylogenetic analysis showed a clade formed only by Zygosaccharomyces strains isolated from the brood cells of different species of stingless bees. Ergosterol was quantified by GC-MS analysis and three isolated strains recovered from the brood cells stood out by their higher steroidal content. These results obtained so far allow us to infer that Zygosaccharomyces is likely a common symbiont of different species stingless bees.

São Paulo Research Foundation (FAPESP), nº process 2018/03650-0

340 Use of Next-Generation Sequencing to Characterize Changes in Water Microbiota Across an Urban Watershed in San Juan Puerto Rico

Uso de Secuenciación de Nueva Generación para Caracterizar una Cuenca Urbana en San Juan de Puerto Rico

Eduardo Tosado1, Frances Vázquez2, Ernesto Torres2, Filipa Godoy-Vitorino1. (1) Microbiología y Zoología Medica, Medicina, Universidad de Puerto Rico, Recinto de Ciencias Medicas (2) Departamento de Ciencias Naturales, Universidad Interamericana de Puerto Rico

The Rio Piedras river is the most important watershed in the urban area of San Juan, Puerto Rico. Throughout years, this watershed has been anthropogenically impacted by urban development and contaminants. Currently, only culture dependent methods are used to evaluate water microbial diversity and quality. We hypothesized that the structure and diversity of the water bacterial communities changed according to the anthropogenic impact levels. To test our hypothesis, we performed a molecular 16S rDNA profiling to a watershed gradient using next-generation sequencing. Water samples were collected on the river in four sites over an urbanization gradient. Water was filtered, gDNA was extracted from the filters and 16S rDNA V4 region genes were sequenced by Illumina MiSeq. Analyses were done using QIIME1 with the SILVA database as reference. A total of 29 phyla and 213 genera were found, in varying complexity along river sites. The less impacted site showed only 5 phyla with a dominance of Proteobacteria and Actinobacteria the medium impact sites had 15 phyla and a dominance of Chlorobi, Actinobacteria and Bacteroidetes while the most impacted site had a higher diversity and number of phyla (26) with a dominance of Proteobacteria, Firmicutes and Bacteroidetes. With a 16S rDNA approach, we were able to define the dynamic microbiota of this urban watershed to a much more detailed depth, revealing association of bacterial diversity to anthropogenic impact. We found an unprecedented diversity of microbial communities in water samples directly linked to an increase in human impact of overall environmental bacteria.

341 Gut Microbiota of Four Adult Caribbean Sea Urchins with Different Trophic Niches

Microbiota Intestinal de Cuatro Erizos de Mar Adultos del Mar Caribe y de Diferentes Nichos Troficos

Eduardo Tosado-Rodriguez1, Rodríguez-Barreras Ruber2, Godoy-Vitorino Filipa1. (1) Microbiología y Zoología Medica, Medicina, Universidad de Puerto Rico, Recinto de Ciencias Medicas (2) Departamento de Biología, Universidad de Puerto Rico, Recinto de Bayamon

Sea urchins are considered one of the most common benthic grazers in tropical marine ecosystems and can exert a strong influence in the community structure. The sea urchins Diadema antillarum, Echinometra lucunter, Lytechinus variegatus, and Tripneustes ventricosus are the most common species in the Caribbean shallow water ecosystems. Unfortunately, we lack basic knowledge of the molecular ecophysiology of these sea urchin species, particularly with respect to their bacterial microbiota. Here, we characterized the gut microbiota of four Caribbean sea urchins collected in the Northeastern coast of Puerto Rico.We compared their ecogenomic composition in different niches, and in varying water temperatures to be able to project how climate change will affect this species. This study will thus be the steppingstone to properly understand the microbe-host interactions in this echinoderm system and how it varies with sea conditions and dietary niches. A total of 126 samples were sequenced using Illumina MiSeq and characterized QIITA and QIIME to establish a baseline bacterial profile of gut digesta of sea urchins within the herbivorous (seagrass) and omnivorous (coral) biotopes, inhabiting Puerto Rico shallow waters.

342 Megathyrsus maximus and Brachiaria decumbens root-associated microbiome in a phytoremediation system of petroleum hydrocarbon contaminated soils

Microbioma asociado a raíces de Brachiaria decumbens y de Megathyrsus maximus en un sistema de fitorremediación de suelos contaminados por hidrocarburos derivados del petróleo

Melissa Uribe Acosta1, Diego León Flórez Olarte1, Nancy Johanna Pino Rodríguez2, Gustavo Antonio Peñuela Mesa1. (1) Laboratorio GDCON, Facultad de Ingeniería, Universidad de Antioquia (2) Laboratorio GDCON, Escuela de Microbiología, Universidad de Antioquia (Sponsored by Departamento Administrativo De Ciencia, Tecnología E Innovación, COLCIENCIAS)

La contaminación del suelo por hidrocarburos es uno de los grandes problemas ambientales en la actualidad. La rizoremediación es una técnica prometedora, basada en la asociación entre plantas y microorganismos para la remoción de contaminantes, pero su éxito depende de las comunidades microbianas del suelo. Este estudio evaluó la estructura de las comunidades bacterianas asociadas a raíces de Brachiaria decumbens y de Megathyrsus maximus, cultivadas en suelos contaminados con hidrocarburos. Los ensayos se realizaron en invernadero por 3 meses, con 5 réplicas por planta y control sin plantar. Los suelos fueron evaluados al inicio y final del experimento para determinar la concentración de hidrocarburos, variables fisicoquímicas y la estructura de las comunidades bacterianas mediante la secuenciación del gen 16S rARN con Illumina. Al finalizar la experimentación se encontró una disminución de 43,95% de Hidrocarburos totales del petróleo (TPH) con M. maximus estadísticamente significativa (p<0,05) respecto al control. El análisis PERMANOVA para las distancias weighted UniFrac mostró diferencias significativas entre M. maximus y el control y el análisis de abundancia diferencial con ANCOM encontró 1351 Amplicon sequence variants (ASVs) con diferencias significativas entre las que se encontraron géneros y familias descritos en matrices ambientales como Oligoflexales, Phycisphaerales y Taibaiella, claves en el ciclo del nitrógeno como Bradyrhizobium, Pirellula, Opitutus, Chryseobacterium y Azospirillaceae y asociadas a la degradación de contaminantes como Alkanibacter y Phenylobacterium. Estos resultados indican una relación entre las comunidades bacterianas y la rizoremediación de hidrocarburos y señala taxa bacterianos claves que deben ser analizados para optimizar el proceso.

Departamento Administrativo de Ciencia, Tecnología e Innovación, COLCIENCIAS

343 Functional bioprospecting approach for the obtention of a thermoactive and thermostable nitrilase with potential biotechnological applications

Enfoque de bioprospección funcional para la obtención de una nitrilasa termoactiva y termoestable con potenciales aplicaciones biotecnológicas

Patricio Uribe-Redlich1,2, Maximiliano Amenabar2, Jenny Blamey3,2. (1) Universidad de Chile (2) Fundación Científica y Cultural Biociencia (3) Universidad de Santiago de Chile

Industrial applications heavily rely on chemical catalysts to increase the rate of reactions. These reactions usually involve the use of toxic compounds, are poorly efficient and produce high amount of biproducts that can pollut the environment. This is especially true in nitrile-derived synthesis of carboxylic acids, where toxic compounds are used. Nitrilases are highly efficient biocatalysts that directly convert nitriles into its corresponding carboxylic acid, producing low amount of biproducts, allowing to decrease overall production costs and environmental pollution associated to industrial processes. However, although these enzymes have been shown to be a good alternative to chemical catalysts, most of the nitrilases reported to date are from mesophilic origin, thus active in a low temperature range (20-60°C), which have limited their use in biotechnological applications where harsh conditions are present. Here we described a functional bioprospecting approach for the environmental screening of hyperthermophilic microorganisms with nitrilase activity. A hyperthermophilic archaeon belonging to thePyrococcus genus was isolated from Deception Island, Antarctica. This microorganism was able to grow in the presence of benzonitrile displaying a high nitrilase activity. Biochemical characterization of the purified nitrilase indicated this enzyme is thermostable, havingan optimal activity at 85°C. This enzyme can use phenil-glycine-nitrile, benzonitrile, 2-cyanopyridine, 3-cyanopyridine and butyronitrile, showing a versatile substrate specificity in contrast to previously reported nitrilases that display high specificity for few substrates. A recombinant version of this enzyme was succesfully generated and characterized. Its biochemical characterization is presented and discussed in context of potential biotechnological applications and/ or bioremediation capabilities.

344 Microbial responses to organic matter additions in contrasting areas in Martinez and Baker fjords

Respuestas de microorganismos a las adiciones de materia orgánica en áreas contrastantes en los fiordos Martínez y Baker

Valentina Paz Valdes1, Humberto González3,2, Ricardo Giesecke2, Camila Fernandez1,4, María Jesús Galvez5, Veronica Molina5. (1) Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción (2) Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile (3) Centro de Investigación Dinámica de Ecosistemas Marinos de Altas Laltitudes, Universidad Austral de Chile (4) Laboratoire d´Océanographie Microbienne, Observatoire Océanologique Banyuls/Mer, Unversité Pierre et Marie Curie, Univ Paris 06 (5) Departamento de Biología y Programa de Biodiversidad, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha (Sponsored by Veronica Molina)

Patagonian fjords in southern Chile are characterized by high spatial variability in physical, biological and chemical characteristics influencing organic matter degradation by aquatic microbial communities. These communities are naturally subjected to organic matter originated from terrestrial (drainage, rivers, precipitation and ice melting) or from seawater at deep layer. Here, we study the response of estuarine and marine bacterioplankton of two sizes class of bacteria (0.7 µm and 1.6 µm), from the head and mouth of the fjord to organic matter enrichment. To study this, bacteria composition, picoplankton abundance and dissolved organic carbon (DOC) was determined. Our results showed that estuarine and marine bacterioplankton was dominated by different Proteobacteria classes in control experiments (natural conditions without organic matter addition), characterized by Alphaproteobacteria (mainly Rickettsiales) and Gammaproteobacteria, respectively. An increase of Alphaproteobacteria, mainly Rhodobacterales and Flavobacteria was observed as a result of the organic matter addition and time course of the experiment, independently of the origin of the community or size fractions analyzed. These changes were associated with organic matter degradation, with a slight decrease of DOC concentration after eight hours of incubation in both treatments, with and without organic matter addition, and in both areas. Cell number increase at different incubation times, with a higher increase in the treatment with organic matter addition (>2x105cell mL-1) in both size classes. We conclude that the organic matter additions can significantly modify the structure of microbial communities favoring groups adapted to rapidly react to changes in their organic matter availability.

Programa CIMAR 20, FONDECYT 1171324

345 Antibiotic resistance of Clavibacter michiganensis subsp. michiganensis Chilean strains isolated from tomato plants

Resistencia a antibióticos de cepas chilenas de Clavibacter michiganensis subsp. michiganensis aisladas de plantas de tomate

Miryam Valenzuela1, Valentina Mendez1, Marianela Gonzalez2, Iván Montenegro3, Ximena Besoain4, Michael Seeger1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología DAL, Universidad Técnica Federico Santa María (2) Instituto de Quimica, Pontificia Universidad Católica de Valparaíso (3) Escuela de Obstetricia y Puericultura, Medicina, Universidad de Valparaíso (4) Escuela de Agronomía, Pontificia Universidad Católica de Valparaíso

Clavibacter michiganensis subsp. michiganensis (Cmm) is the causal agent of bacterial canker of tomato. Commercial products containing mix of antibiotics, i.e. streptomycin plus oxytetracycline and gentamicin plus oxytetracycline are used to control this pathogen in Chile. This work aimed to evaluate the Cmm resistance to streptomycin, gentamicin and oxytetracycline, and to analyze the presence of resistance-related genes in Cmm strains from Chile. A collection of 25 Cmm strains isolated between 1996 and 2015 from different locations in Central Chile was analyzed. Minimum inhibitory concentration (MIC) of these antibiotics was determined. Presence of antibiotic resistance-related genes in all Chilean strains was assessed using PCR and whole-genome sequencing techniques. MIC results showed that the 25 strains were sensitive to gentamicin and oxytetracycline with MIC values ≤10 µg/mL. Four strains out of 25 were highly sensitive to streptomycin, with MIC values <2 µg/mL. The remaining 21 strains possessed MIC of streptomycin ≥100 µg/mL. The strB gene, encoding an aminoglycoside 6-phosphotransferase that inactivates streptomycin, was detected in all Chilean strains, including sensitive and resistant strains. In the 21 resistant Cmm strains, a mutation in codon 43 of the rpsL gene was determined, explaining their high resistance to streptomycin. Interestingly, the four streptomycin-sensitive Cmm strains did not possess this mutation. This study proposes that the continuous application of streptomycin to control Cmm leads to emergence of resistant strains. Therefore, novel alternatives should be established to control this plant pathogenic bacterium.

CONICYT Doctorado Nacional (MV) y PIA-Anillo GAMBIO ACT172128 (MS, VM, MV).

346 Agroecosystem services of Pseudomonas sp. strain ABC1 (Pseudomonas chilensis ABC1)

Potencial agrícola de Pseudomonas sp. cepa ABC1 (Pseudomonas chilensis ABC1)

Daniel Valenzuela-Heredia1, Oscar Franchi1, Marisol Belmonte 2, Jose Luis Campos1. (1) Energía y medio ambiente, FIC, UAI (2) Ingeniería, Ingeniería, UPLA

La agricultura es la base de la sociedad y su desarrollo es función de la demanda. Estrategias que permitan aumentar la capacidad agrícola de suelos es fundamental para satisfacer las necesidades actuales de alimento. La carencia de hierro biodisponible en los suelos es una de las principales deficiencias a las que se exponen los cultivos, estimándose un efecto sobre el 30% de la agricultura actual. El género Pseudomonas se caracteriza por la producción de sideróforos, moléculas quelantes de hierro que tienen la capacidad de nutrir con Fe cultivos de importancia agrícola. El uso de estas moléculas es clave para sustituir la aplicación de EDTA y análogos, por estar cuestionados ambientalmente. Limitaciones productivas han frenado la utilización de sideróforos a escala industrial, así Pseudomonas sp. ABC1 se presenta como una plataforma para la producción de sideróforos que pueden llevar estas moléculas desde el laboratorio a la industria, por ejemplo para aplicación agrícola. Se describe un proceso productivo de bajos requerimientos técnicos y económicos que utiliza Pseudomonas sp. ABC1 para producir sideróforos del tipo pioverdina. Fito ensayos en Vaccinium sp. y Arabidopsis thaliana demostraron que la aplicacion de este sideroforo es capaz de estimular el vigor de las plantas.

FONDECYT POSTDOCTORADO 3180762

347 Isolation of UV-resistant bacteria from hyper-extreme environments of the Antarctic (Union Glacier): application in the biosynthesis of highly photostable fluorescent nanoparticles (Quantum Dots)

Aislamiento de bacterias resistentes a radiación UV desde ambientes hiper-extremos de la Antártica (Glaciar Unión): aplicación en la biosíntesis de nanopartículas fluorescentes (Quantum Dots) altamente fotoestables

Matías Vargas-Reyes1, Nicolás Bruna1, Claudio Navarro1, José Manuel Pérez-Donoso1. (1) BioNanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Ciencias de la Vida, Universidad Andrés Bello

Los Quantum Dots generados por organismos vivos (bio-QDs) poseen grandes ventajas de ser utilizados en aplicaciones fotovoltaicas y en biomedicina. Sin embargo, presentan una pobre estabilidad frente a la exposición a la radiación UV. Con tal de solucionar este problema, los microorganismos extremófilos resultan de gran interés para sintetizar bio- QDs con nuevas y únicas propiedades. El Glaciar Unión, ubicado a 1000 km del Polo Sur, presenta índices de radiación UV permanentes durante el verano (24 h), el cual es amplificado por el albedo. Esta zona resulta interesante para la búsqueda de microorganismos capaces de generar moléculas que contrarresten los efectos de la radiación UV. En esta investigación se evaluó la capacidad de bacterias aisladas desde Glaciar Unión resistentes a la radiación UV de sintetizar bio-QDs de CdS. Se tomaron muestras de suelo a partir de los sitiosi) Elephant Head y ii) Rossman Cove. La obtención de aislados se realizó mediante la suspensión de suelo en buffer PBS, con posterior incubación en medio sólido R2A a 10 y 28 °C. Además, se logró cultivar 2 bacterias utilizando suelo del lugar, como sustrato de crecimiento. Las bacterias fueron identificadas mediante secuenciación del gen ribosomal 16S, correspondiendo a los géneros Rodhococcus y Arthrobacter. Los aislados obtenidos fueron capaces de soportar altas dosis de radiación UV-C (sobre 300 J/m2). Finalmente, la tolerancia a la exposición a la radiación UV (fotoestabilidad) será evaluada en los bio-QDs de CdS sintetizados por las bacterias resistentes a UV-C.

INACH RT-25_16

348 Anogenital Bacteria Associated to HPV Infections in Puerto Rican Women

Bacterias Anogenitales Asociadas a Infecciones por VPH en Mujeres Puertorriqueñas

Frances Vazquez-Sanchez2,1, Brayan Vilanova-Cuevas2,1, Gilmary Ortiz2,1, Ana P. Ortiz3, Filipa Godoy-Vitorino1. (1) Microbiology and Medical Zoology, University of Puerto Rico, Medical Sciences Campus (2) Science and Technology, Inter American University of Puerto Rico, Metropolitan Campus (3) University of Puerto Rico Comprehensive Cancer Center

Anogenital human papillomavirus (HPV) are the world’s most commonly diagnosed sexually transmitted infections and high-risk types are linked to cervical and anal neoplasia. Susceptibility to HPV infections is related to the microbial communities of these genital surfaces, which are interfaces between the host and environment. We hypothesized that bacterial communities may differ in the anus and cervix and may reveal populations associated to HPV infections in these two body sites. To test this hypothesis, we characterized the microbiota of a cross-sectional population-based sample of Puerto Rican women (self-sampled) from the San Juan metropolitan area (n=506 samples) and related them to anogenital HPV infections (HPV typing performed by PCR; HPV types classified as high-risk and low-risk). The bacterial characterization was performed through sequencing of the 16S rRNA gene V4 region with the Illumina platform. Significant differences in alphadiversity were found according to patients BMI (p-value <0.00005), but not according to HPV risk (p-value >0.05) in any of the body sites. Indeed, overall anal communities were dominated by OTUs within Prevotella and Bacteroides, while cervical samples were dominated by Lactobacillusand Gardnerella. Although not significant, cervical samples of HPV positive patients revealed a decrease in enrichment of L. iners, while a decrease in Bacteroides was associated with anal HPV infections. Although more analyses are needed, our data suggests that specific cervical and anal keystone bacteria change in abundance with HPV infections, which could pave the way to the development of early detection methods or novel probiotics for the prevention of anogenital HPV-related malignancies.

Research reported in this publication was supported by an Institutional Development Award (IDeA) from the National Institute of General Medical Sciences of the National Institutes of Health under grant number P20GM103475.

349 Fecal contamination, pathogenic bacteria and antibiotic resistant-bacteria in household water from the Mezquital Valley, Hidalgo, Mexico

Contaminación fecal, bacterias patógenas y bacterias resistentes a antibióticos en agua de tomas domiciliarias del Valle del Mezquital, Hidalgo, México

Nallely Vázquez1, Manuel Mora López 2, Marisa Mazari Hiriart1. (1) Laboratorio Nacional de Ciencias de la Sostenibilidad, Instituto de Ecología, Universidad Nacional Autónoma de México (2) Universidad Nacional Autónoma de México

El agua residual para riego puede infiltrarse y contribuir a la recarga de acuíferos. En el Valle del Mezquital (VM), área más grande del mundo regada con agua residual, la infiltración ha aumentado 13 veces. Durante 2015-2017 colectamos agua de 20 tomas domiciliarias en Tula y Tlahuelilpan, VM, y en cuatro tomas de una zona control regada con agua subterránea. Suponemos que el agua residual contamina las fuentes de abastecimiento y la calidad del agua es mejor en la zona control. El agua se procesó mediante cultivo para indicadores de contaminación fecal (coliformes fecales, Escherichia coli); por PCR para E. coli patógenas: (EAEC-enteroagregativa, EHEC-enterohemorrágica, EPEC- enteropatogénica, ETEC-enterotoxigénica), y por MicroScan para E. coli resistentes a antibióticos. El agua distribuida a la población es segura si está libre de bacterias; sin embargo, el 48% de las muestras presentó contaminación fecal, el 12% patógenas y el 11% resistencia. El agua de Tula, zona más urbanizada e industrializada presentó 18.5 coliformes/100 mL en promedio. En Tlahuelilpan y en la zona control las medias fueron 1.8 y 4.1 coliformes/100 mL. En Tula y en la zona control detectamos EHEC, EPEC y ETEC, en Tlahuelilpan detectamos EAEC. Esto depende del almacenamiento del agua dada una distribución intermitente (P= 0.0034) y de deficiencias en la desinfección (cloración). Se requiere mejorar la cobertura de agua para uso humano y de servicios básicos de saneamiento a las poblaciones. El VM se sugiere como modelo para la implementación del Objetivo de Desarrollo Sostenible 6 en agua para consumo y riego.

Prevalencia de enfermedades Gastrointestinales y presencia de Multidrogoresistencia en comunidades Expuestas al reúso de agua residual en el Valle del Mezquital, Hidalgo” financiado por el Consejo Nacional de Ciencia y Tecnología, proyecto número PDCPN2014-14-247779

350 Bacterial diversity associated with the degree of contamination by heavy metals in sediments from the Reconquista River, Buenos Aires, Argentina, and its role in bioremediation processes

Diversidad bacteriana asociada al grado de contaminación por metales pesados en sedimentos del Rio Reconquista, Buenos Aires, Argentina, y su rol en procesos de biorremediación

Celeste Grimolizzi1, Susana Vazquez2, Natalia Porzionato1, Ana Tufo1, Agustina Ziliani1, Angela Cabezas Da Rosa3, Gustavo Curutchet1. (1) Instituto de Investigación e Ingeniería Ambiental, Universidad de San Martín, Pcia. de Buenos Aires, Argentina (2) Instituto de Nanobiotecnología NANOBIOTEC UBA-CONICET, Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina (3) Departamento de Ciencias Ambientales, Universidad Tecnológica (UTEC), Durazno, Uruguay

Los sedimentos de los cursos de agua contaminada acumulan mucha materia orgánica (MO) y contaminantes persistentes como metales pesados que afectan la estructura fisicoquímica y la microbiota de los sedimentos. Dado el riesgo ambiental, es imprescindible desarrollar tecnologías de remediación como la recuperación de metales por biolixiviación. En este trabajo analizamos la diversidad microbiana (secuenciación Illumina-MiSeq de amplicones del gen RNAr16S) de sedimentos fluviales en una zona no contaminada (DR) y otra con contaminación moderada/ alta (R8) y la evolución de la microbiota de R8 en reactores sin y con adición de fuente de electrones alternativa, con y sin bioaumento con bacterias nativas hierro y azufre oxidantes, monitoreando la extracción y especiación de metales, acidificación y poblaciones bacterianas. En DR y R8 dominó el filo Proteobacteria, seguido de Nitrospirae (DR) y Bacteroidetes, Chloroflexi y Caldiserica (R8) y se aislaron bacterias afiliadas a Acidithiobaclllus, Clostridium, Desulfovibrio y Shewanella. En los biorreactores el Eh subió en 20d (-200 a +400 mV), comenzando la oxidación de sulfuros y MO. Luego, los adicionados acidificaron y lixiviaron metales. La microbiota inicial, dominada por anaerobios, se enriqueció en aerobios y oxidantes de azufre. El material tratado formó una estructura tipo suelo, macroporosa con buena ciculación de agua y aire, probablemente por formación microbiana de cementantes como el CaSO4. No hubo diferencias con el bioaumento, llegando todos los biorreactores al mismo estado luego de 4 meses de operación, mostrando gran potencial de la microbiota nativa del Río Reconquista para remediar los sedimentos cuando se aplica un proceso adecuado.

PICT2017- 2787, MINCyT/FONCyT, 2018. OBSERVATORIO AMBIENTAL CARCOVA Proyecto Interdisciplinario “Dialogo entre las Ciencias 2015”. UNSAM. 2018-2020.

351 Phosphorus availability in lichen-associated substrate in forest and grassland of Reserva Nacional Coyhaique, Chile

Disponibilidad de fósforo en sustrato asociado a líquenes de bosque y pradera de la Reserva Nacional Coyhaique, Chile

Karla Veas1, Katerin Almendras1, Cecilia Muster1, Karla Villalobos1, María Camila Morales1, Margarita Carú1, Julieta Orlando 1. (1) Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile

Los líquenes son asociaciones simbióticas compuestas por un hongo y un alga y/o cianobacteria. Un componente liquénico adicional lo constituyen las comunidades bacterianas asociadas a éstos, que cumplirían un rol esencial en el éxito ecológico de los líquenes, participando en procesos claves del ciclo de nutrientes, incluyendo el ciclo del fósforo (P). El P es un macronutriente esencial para el crecimiento y desarrollo de los organismos, el cual existe en formas orgánicas (Po) e inorgánicas (Pi) en el suelo, clasificándose según su biodisponibilidad en P soluble, lábil y no lábil. Estudios en gradientes altitudinales de montañas, muestran una tendencia al aumento de P en suelos de sitios ubicados a una baja altitud, probablemente relacionado a la caída de la hojarasca desde losárboles, fenómeno que disminuiría al perderse vegetación cumbre arriba. Con el objetivo de evaluar la influencia de líquenes sobre la disponibilidad de P en sitios con diferente altitud y vegetación, estudiamos distintas fracciones de P en suelo asociado a líquenes (sustrato) de un bosque de Nothofagus y una pradera altoandina en la Reserva Nacional Coyhaique. Se seleccionaron muestras de cianolíquenes del género Peltigera, se obtuvo el sustrato asociado y se evaluó la disponibilidad de P mediante fraccionamiento de Hedley. Si bien se observó una mayor disponibilidad de P soluble, Pi lábil y Pi moderadamente lábil en sustrato de bosque en comparación a pradera, las fracciones de Po no fueron significativamente diferentes entre ambos sitios, sugiriendo una influencia de la microbiota liquénica sobre la concentración de Po del sustrato.

FONDECYT 1181510

352 Nutrient effect of goose and European hare faeces on bacterial carbon consumption in a proglacial lake

El efecto de los nutrientes provenientes de las heces de cauquén y de liebre europea sobre el consumo de carbono bacteriano en un lago proglaciar

Evelyn Nathalie Vega1, Marcela Bastidas Navarro1, Beatriz Modenutti1. (1) Limnología, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue - Instituto de Investigaciones en Biodiversidad y Medioambiente

Los animales que frecuentan los ambientes acuáticos influyen en los ingresos de materia orgánica disuelta (MOD) vía sus heces aportando nutrientes importantes para la producción bacteriana, como carbono (C), fósforo (P) y nitrógeno (N). La retracción glaciar reciente en Patagonia Norte ha provocado la formación de lagos proglaciares. Se caracterizan por ser lagos oscuros, debido a las arcillas glaciares, y colonizados exclusivamente por bacterias. Nuestro objetivo fue analizar la respuesta de las bacterias del Lago proglaciar Ventisquero Negro (Monte Tronador) a la adición de nutrientes disueltos provenientes del lixiviado de heces de cauquenes autóctonos (Chloephaga poliocephala) y de liebres europeas (Lepus europaeus) que frecuentan el ambiente periglaciario. Se realizó un experimento de incubación de agua de lago durante 14 días en condiciones de oscuridad con tres tratamientos: sin enriquecimiento, con enriquecimiento: con lixiviado de heces de cauquén y con lixiviado de heces de liebre. Se analizó el contenido de nutrientes de las heces y sus lixiviados, respiración bacteriana, consumo de C a corto y largo plazo, abundancia y biomasa bacteriana. Las heces y los lixiviados de heces de cauquén fueron más ricas en nutrientes que las de liebre. El enriquecimiento con nutrientes afecta positivamente a las variables estudiadas. Nuestros resultados indican que las bacterias consumen más C por la adición de compuestos disueltos provenientes de heces especialmente de cauquén. Por lo tanto, las aves y los pequeños mamíferos cumplen un importante papel ecológico abasteciendo de MOD alóctona y nutrientes, a través del lixiviado de sus heces, en este ecosistema.

-Consejo Nacional de Investigaciones Científicas y Técnicas -FONCyT. Efecto del cambio climático en el incremento de nutrientes, el bucle microbiano y el plancton de ambientes acuáticos andinos norpatagónicos. FONCyT PICT 2015-0418. B. Modenutti.

353 Selection of psychrotolerant bacterial consortia: isolation from wild flora of Chile, plant growth- promoting activities and effects on tomato seeds at low temperatures

Selección de consorcios bacterianos psicrotolerantes: aislamiento desde flora silvestre de Chile, actividades promotoras del crecimiento vegetal y efectos sobre semillas de tomate a bajas temperaturas

Paulina Vega-Celedón1, Guillermo Bravo1, Michael Seeger1. (1) Quimica, Quimica, Universidad Tecnica Federico Santa Maria

Every year agriculture is affected by low temperatures. Central and southern agricultural zones of Chile are the most affected areas by this abiotic stress.Psychrotolerant plant growth-promoting bacteria have the ability to promote plant growth at low temperatures. The aim of this study was to select psychrotolerant bacterial consortia through the evaluation of its plant growth-promoting activities and effects on tomato seeds at cold stress conditions. Psychrotolerant bacteria strains were isolated from wild flora sampled during winter 2015. Bacterial cell survival at temperatures below zero was analyzed to determine the psychrotolerant potential. Strains were identified by 16S rRNA gene sequence. The auxin production was evaluated by growths supplemented with tryptophan with the Salkowski colorimetric method. The phosphate solubilization was analyzed on Pikovskaya medium. Biocontrol activities against phytopathogenic ice nucleation active bacteria Pseudomonas syringae and Pectobacterium carotovourum was evaluated by cross streak method. Eight strains presented the best activities and were selected to conform bacterial consortia. The plant growth-promoting effect on tomato seeds was evaluated under the following treatments with the selected consortia: Bacterial consortium 1 (BC1), 2 (BC2), 3 (BC3) and 4 (BC4) and negative control. Seeds were sterilized and embedded in the different treatments, and ten seeds were germinated with wet filter paper at 14 °C for 12 d. Increased values (P <0.05) were observed in germination percentage and the root length after BC2, BC3 and BC4 treatments. These bacterial consortia have the biotechnological potential for further growth promotion assays on other seeds plants at cold stress.

Conicyt PhD fellowship (PVC, GB), Anillo GAMBIO ACT172128, FONDECYT 1151174, USM and PMI InES FSM1402_B_02 (MS) grants.

354 Distribution and diversity of anoxygenic phototrophic bacteria in a microbial mat of Salar Huasco, Chile

Distribución y diversidad de bacterias fotótrofas anoxigénicas en un tapete microbiano del Salar de Huasco, Chile

Drina Vejar1,2, Diego Cornejo1, Pablo Aguilar1, Cristina Dorador1,2,3. (1) Laboratorio de Complejidad Microbiana y Ecología Funcional, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile. (2) Centro de Biotecnología y Bioingeniería (CeBiB), Universidad de Antofagasta (3) Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta

Los salares del norte de Chile son ecosistemas acuáticos dominados por microorganismos. En los tapetes microbianos es posible reconocer una alta diversidad de Bacteria y microorganismos fotosintéticos. Se ha reconocido que las bacterias fotótrofas anoxigénicas tienen un rol importante en la productividad primaria, sin embargo, su diversidad y función ha sido escasamente estudiada. En este trabajo se analizó la composición y diversidad de bacterianas fotótrofas anoxigénicas en distintas capas estratificadas de un tapete microbiano (4 capas, 1mm de espesor cada una) del Salar de Huasco. La diversidad microbiana (gen 16S rRNA) fue analizada mediante T-RFLP (enzimas AluI y DpnI). La comunidad fotótrofa fue analizada a través del clonamiento y secuenciación del gen bchY que está relacionado con la síntesis de bacterioclorofila. Se obtuvo un total de 37 unidades taxonómicas operacionales (OTUs) en digestiones con la enzima AluI y un total de 41 OTUs con la enzima DpnI. Los índices de riqueza y diversidad obtenidos por análisis de T-RFLP no mostraron diferencias (p>0,05) entre las capas del tapete microbiano; sin embargo, las capas superiores del tapete microbiano se asemejan entre ellas, presentando menor riqueza y diversidad (15-17 OTUs; H´= 2,4), al contrario de las capas inferiores (26-27 OTUs; H´= 3,2). En el caso del análisis del gen bchY, se obtuvo un total de 268 secuencias, las cuales fueron afiliadas mayormente a Proteobacteria (α, β y γ). Además, se pudo verificar un patrón de distribución vertical específico para cada capa del tapete microbiano caracterizado por la presencia de: i) Bradyrhizobium sp. (capa 1; 33, 3%); ii) Rubrivivax sp. (capa 2; 11,1%); iii) Rhodopseudomonas sp. (capa 3; 10,1%) y iv) Sphingomonas sp. (capa 4, 9,2%). Los resultados indican que miembros del clado Roseobacter están presentes en todas las capas del tapete y tienen la mayor diversidad genética en el grupo de las AAPB.

Funding: Fondecyt 1181773; CeBiB FB0001 (PIA-CONICYT)

355 Effect of arbuscular mycorrhizal fungi and plant growth-promoting rhizobacteria on volatile organic compounds in Vitis vinifera cv. Cabernet Sauvignon roots

Efecto de hongos micorrízicos arbusculares y bacterias promotoras del crecimiento vegetal sobre los compuestos orgánicos volátiles en raíces de Vitis vinifera cv. Cabernet Sauvignon

Alexis Andrés Velásquez1, Paulina Vega-Celedón1, Grazia Fiaschi2, Monica Agnolucci2, Luciano Avio2, Manuela Giovannetti2, Claudio D’Onofrio2, Michael Seeger1. (1) Química, Universidad Técnica Federico Santa María (2) Agriculture Food and Environment, University of Pisa

Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) are beneficial microorganisms that may stablish symbiotic association with grapevine roots, improving stress tolerance and plant growth. AMF and PGPR enhance the production of plant secondary metabolites, including volatile organic compounds (VOCs), that are involved in plant-environment interaction and are related to plant defense. The aim of this work was to analyze the effects of AMF and PGPR on root VOC emission in Vitis vinifera cv. Cabernet Sauvignon to gain insight into the potential role of plant-rhizosphere microorganisms in vineyard growth and health. Grapevines were inoculated with the mycorrhizal fungus Funneliformis mosseae IN101 and/or the PGPR Ensifer meliloti TSA41. Fifty- eight VOCs were identified usingheadspace solid-phase microextraction (HS-SPME) coupled to gas chromatography/ mass spectrometry. VOC emission was highly induced by IN101, increasing by 69%,compared with control plants. By contrast, TSA41 only increased VOC emission by 11%. Monoterpenes were strongly enhanced by IN101, increasing by 87% compared with control plants. Interestingly, monoterpene alcohols related to plant defense were increased. Knowledge of the positive effects of AMF and PGPR on grapevine VOCs may lead to their use as bioinoculants in an integrated and sustainable management of vineyards.

Beca Doctorado Nacional CONICYT (AV, PV), CONICYT PIA Anillo de Investigación en Ciencia y Tecnología ACT172128 Proyecto GAMBIO (MS), Dirección General de Investigación, Innovación y Postgrado y Programa de Incentivos a la Iniciación Científica USM

356 Analysis of the role of FtsZ domains in the cell division of Anabaena sp. PCC7120

Análisis del rol de los dominios de FtsZ en la división celular de Anabaena sp. PCC7120

Sebastián Ignacio Velozo1, Blanca Aguila-Llanquilef1, Francisco Barahona1, Mónica Vásquez1. (1) Genetica molecular y microbiologia, ciencias biologicas, Pontificia Universidad Católica de Chile

Raphidiopsis raciborskii (in the past Cylindrospermopsis raciborskii) species belongs to order Nostocales, is a filamentous diazotrophic cyanobacterium. Along the filament, the multiseptum formation can be observed. However, the cause of this phenotype is still unknown. In this study, we explored the role of FtsZ, akey protein involved in cell division, over the septum formation and other cellular features. Within the bacterial cytoskeleton, FtsZ protein plays a crucial role during cellular division, where this protein serves as a scaffold to the process of cytokinesis and septum formation (protein complex involved in the septum formation is named septosome). In silico analysis of FtsZ from R. raciborskii showed an increase in proline frequency of 8% approximately in this variable region respect to the FtsZ of Anabaena sp. PCC7120 (where the multiseptum formation is not observed). To evaluate the role of FtsZ from R. raciborskii in the multiseptum formation, we replaced ftsZ in Anabaena with the one from R. raciborskii by homologous recombination. Preliminary results gave a statistically significant reduction of ~50% on cellular size and formation of mini-cells on Anabaena sp. PCC7120, suggesting a faster contraction on the cytokinesis or a higher frequency of this process, the last option is coherent with the phenotypes observed in R. raciborskii. The mutant also presents irregular division planes and differences on septum thickness, indicating the critical role of the proline-rich region in the interaction with other proteins of the septosome.

Fondecyt 1161232

357 Effect of temperature and thermal-gradient adaptation on photosynthesis ofFischerella thermalis

Efecto de la temperatura y la adaptación a gradientes termales en la fotosíntesis de Fischerella thermalis

Pablo Vergara-Barros1, Beatriz Díez2,1. (1) Genética molecular y microbiología, Ciencias biológicas, Pontificia Universidad Católica De Chile (2) Centro de Ciencia del Clima y Resiliencia (CR)2, Universidad de Chile

Oxygenic photosynthesis is one of the most relevant processes in nature, being the entry point of energy to the food chain and releasing oxygen to the atmosphere. However, this biological process has been described as very sensitive and then affected by environmental conditions such as pH, salinity, and temperature. In hot springs, Fischerella thermalis is a key organism of the food chain, providing with the organic carbon and nitrogen to this environment. In Porcelana hot spring, F. thermalis dominates the microbial community at temperatures below 58°C, where different strains showed a differential proteomic pattern depending on its temperature origin, suggesting a niche- specific adaptation. Then, we asked if F. thermalis adapted its photosynthetic activity to the different temperatures over the thermal gradient. To answer this, we evaluated at several temperatures the oxygen production of three F. thermalis strains isolated at different temperatures from Porcelana hot spring and the reference strain F. thermalis PCC 7521. As a result, we found that the strains isolated at higher temperatures can produce oxygen even when they were exposed to higher temperatures than those described as the photosynthetic limit previously suggested for F. thermalis. Meanwhile, the F. thermalis strain from lower temperature origin had a photosynthetic activity similar to the reference strain F. thermalis PCC 7521, both stopped producing oxygen at ~60 °C. These results strongly suggest that the environmental thermal gradient affects F. thermalis photosynthesis performance, generating strains with photosynthetic thermotolerance. Now further experiments are needed to uncover the molecular mechanisms behind this photosynthetic thermal-adaptation.

FONDECYT nº 1105171; FONDECYT nº 1181656; FONDAP (CR)215110009 (CONICYT).

358 Open-Source Paper-Fluidic Device for Bacterial Culture, Communication and Biocomputation

Dispositivo de Papel-Fluido, de libre disposición, para cultivos bacterianos, Comunicación y Biocomputación

Gonzalo Andrés Vidal1, Timothy James Rudge2. (1) Instituto de Ingeniería Biológica y Médica, Ciencias Biológicas, Pontificia Universidad Católica de Chile (2) Instituto de Ingeniería Biológica y Médica, Ingeniería, Pontificia Universidad Católica de Chile

El cultivo bacteriano se ha hecho tradicionalmente en medios en placas de Petri y tubos bacterianos con agitación, el movimiento del medio ayuda al crecimiento bacteriano. Desarrollamos un dispositivo de bajo costo donde las bacterias crecen y nadan en un medio líquido que fluye a través de la matriz sólida inerte del papel que se asemeja mucho más al ambiente natural para algunas bacterias. Similar al lecho de río o tracto gastrointestinal y que permite un gran desempeño para análisis mediante técnicas de fluorescencia ya que está diseñado para acoplarlo al sistema de imagenes de multi-fluorescencia, FluoPi. El flujo de líquido está restringido a canales formados porparedes hidrofóbicas que pueden ser impresas o dibujadas con crayones. El hardware se fabrica a través de impresión 3D y corte láser de acrílico para facilitar el acceso a esta tecnología por parte de toda la comunidad científica. Se caracterizó el crecimiento de bacterias en el dispositivo usando unidades formadoras de colonias. Se demostró comunicación direccional, siguiendo el flujo, entre bacterias con plásmidos que expresan la acil-homoserina lactona sintetasa (emisor), y bacterias con un plásmido que expresa la proteína fluorescente sfGFP en respuesta a lactona. El traspaso de información de forma secuencial es de gran importancia para una aplicación en biocomputación. Usando este dispositivo se crearon biopelículas donde se estudiaron fenómenos de colonización, migración e invasión. Este novedoso dispositivo cuesta menos de $8.500 CLP y permite el estudio de comunidades bacterianas en un mejor modelo de ecosistema para muchas bacterias.

This project was supported by Fondecyt Iniciaci´on 11161046, awarded to TR.

359 Probiotic microbiota of tropical fermented drinks: Mauby and Tepache

Caracterización de la Microbiota Probiotica de bebidas tropicales fermentadas: Mavi y Tepache

Brayan Vilanova-Cuevas2,1, Freddy R Medina1, Carolan Navarro1,2, Enrique Pablo Jove1, Filipa Godoy-Vitorino2. (1) Ciencias Naturales, Ciencias y Tecnologia, Universidad Interamericana de Puerto Rico, Recinto Metropolitano (2) Zoologia y Microbiologia Medica, Universidad de Puerto Rico Escuela de Medicina

Microbial species derived from fermented foods are able to colonize the gastrointestinal tract. As antibiotics and processed foods have a detrimental effect on the human microbiome, it is important to identify new fermented foods and beverages that could benefit us. Mauby and Tepache are tropical fermented beverages made from wood and pineapples respectively. We hypothesized they likely possess probiotic bacteria. We produced a robust microbiota study comparing fermented mauby made with wood a tree (Colubrina elliptica) from Puerto Rico and a vine (Gouania lupuloides) from the Dominican Republic, using different wood material (cortex and medulla), as well as prepared Tepache using pineapple rind (Ananas comosus).The preparations were done in a mini-fermenter at 28°C for ~5-6 days. Genomic DNA extraction was followed by amplification of16S V4 region and sequenced with Illumina MiSeq. Data analyses were done in QIITA and QIIME using the SILVA database as reference. We found a variety of at least 26 different Lactobacilli species. We found a significant dominance ofOenococcus oeni, Lactobacillus mali in PR mauby and dominance of L. ghanensis, L. casei, Lactococcus sp and L. uvarum in the cortex-derived DR mauby. Mauby made with medulla did not yield particularly a probiotic-rich content. Tepache was enriched with L. Paracasei and L. fermentum. Our preliminary data suggest that mauby and tepache are probiotic-rich beverages, containing a variety of Lactobacillaceae OTUs as well as other non-conventional lactic acid bacteria beneficial for human consumption.

360 Structure of native bacterial communities in Carlini Station soils, Antarctica: effects of an accidental oil spill

Estructura de las comunidades bacterianas nativas de suelos de la Base Carlini, Antártida: efectos de un derrame accidental de gasoil

Julia Villalba Primitz1, Déborah Colman2, Edgardo Hernández2, Kian Mau Goh3, Kok-Gan Chan4,5, Chia Sing Chan3, Valeria Careaga6, Diana Castellanos Rodríguez6, Gerhard Kuhn7, Susana Vázquez1,8, Walter Mac Cormack2. (1) Instituto de Nanobiotecnología - Universidad de Buenos Aires (UBA)-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) (2) Instituto Antártico Argentino, Buenos Aires, Argentina (3) Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor, Malaysia (4) International Genome Centre, Jiangsu University, Zhenjiang 212013, China (5) Division of Genetics and Molecular Biology, Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia (6) Universidad de Buenos Aires, CONICET-UMYMFOR, Buenos Aires, Argentina (7) Alfred Wegener Institute-Helmholtz Centre for Polar and Marine Research, Bremerhaven, Alemania. (8) Cátedra de Biotecnología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Buenos Aires, Argentina

El estudio de las alteraciones en la composición de la comunidad microbiana nativa ante un derrame de combustible es clave para inferir el grado de impacto de este evento sobre la microbiota del suelo y aportar conocimientos para el diseño de estrategias que atenúen estos efectos. La Antártida no es la excepción, ya que las principales causas de contaminación de sus suelos son los derrames de hidrocarburos ocasionados durante el transporte, la descarga, el almacenamiento y la distribución de estos combustibles. En este trabajo, la ruptura de una tubería subterránea de combustible en la Base Antártica Carlini se utilizó como escenario natural para evaluar las alteraciones estructurales sufridas por la microbiota nativa del suelo. El ADN de las comunidades bacterianas de suelos con diferentes grados de exposición al derrame (directamente afectados, periféricos y no afectados) se analizó mediante secuenciación de amplicones (V3-V4) del gen RNAr 16S por Illumina-MiSeq y posterior procesamiento usando QIIME y SILVA v132 para la asignación taxonómica. Se determinó la concentración y perfil de hidrocarburos, C-total y orgánico, N-total, P-extraíble, nitrato y amonio. Se observó que el impacto por hidrocarburos afectó la riqueza y la equitatividad de las comunidades, siendo menores en los suelos directamente afectados, en donde predominaron los géneros Sphingomonas, Novosphingobium y Polaromonas. Por otro lado, algunos miembros del Phylum Chloroflexi, presentes en suelos no afectados (36%), fueron detectados en muy baja proporción en los suelos directamente afectados (1,5%) sugiriendo que este grupo podría representar un buen indicador de contaminación en estos suelos.

Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT)-(PICT 2016-7271), Argentina.

Universidad de Buenos Aires-(UBA)-(UBACyT-20020130100569BA), Argentina.

Proyecto IMCONet-(International Research Staff Exchange Scheme)-(FP7404-IRSES, action-318718).

K-G Chan thanked-University of Malaya for financial support (PPP grants-PG136-2016A, PG133-2016A, HIR grant- H50001-A-000027).

361 Comparative analysis of the N2-fixing and phosphate-solubilizing bacterial communities associated with greenhouse-tomato crops

Analisis comparativo de las comunidades fijadoras de nitrogeno y solubilizadoras de fosforo asociadas al cultivo de tomate bajo cubierta

Santiago Adolfo Vio1, Sabrina Soledad García1, Pamela Romina Bernabéu1, Joaquín Ignacio Rilling2, Mariano Pistorio3, Milko Alberto Jorquera2, Maria Flavia Luna1. (1) Laboratorio de Microorganismos de Aplicación en Agricultura, CCT CONICET La Plata / Universidad Nacional de La Plata, Centro de Investigación y Desarrollo en Fermentaciones Industriales; CIC-PBA (2) Laboratorio de Ecología Microbiana Aplicada, Universidad de La Frontera, Departamento de Ciencias Químicas y Recursos Naturales (3) Depto. de Ciencias Biológicas, CCT CONICET La Plata / Universidad Nacional de La Plata, Instituto de Biotecnología y Biología Molecular

The potential plant growth promotion functions of plant-associated bacterial communities have received significant attention in recent years. In this way, we assessed the bacterial functional diversity associated with greenhouse- tomato plants in two sites of the horticultural belt of La Plata, Argentina: Site-I, large story of tomato crops and Site-II, pristine land with its first tomato crop. Total DNA was obtained from samples of bulk soilBS ( ), rhizosphere (Rh) and surface-disinfected root (Rt), stem (St) and fruit (Ft) samples of tomato var. elpida. The diversity of nifH and phoD genes was assessed with PCR-DGGE. Total bacteria (16S-rRNA), phoD and nifH gene abundances were evaluated with qPCR. PCR-DGGE revealed differences in all communities from both sites. For phoD, all samples were different at 70%. For nifH gene, BS and Rh of both sites were different at 70%, whereas plant tissue samples presented large similarities between sites. qPCR revealed similar copy numbers between both sites total and phoD communities (~1014, ~1014, ~1010, ~109, and ~108 16S copies g-1 sample, and ~106, ~106, ~105, ~103 and ~103 phoD copies g-1 sample in BS, Rh, Rt, St and Ft, respectively). For nifH, both sites contained ~106 and ~107 gcopies -1 sample in BS and Rh, respectively. Rt, St and Ft samples were not successfully quantified. Results suggest that (I) agronomic usage of soil in this crop modified the diversity of functional genes in all studied niches; (II) plant selection of its functional internal microbiome might occur; (III) the abundance of specialized bacterial communities remains constant.

362 Bacterial-multispecies bioinput: growth-promotion effect in plants of letucce var. Sagess

Inoculante bacteriano multiespecie: efecto promotor del crecimiento en cultivo de lechuga trocadero var. Sagess

Santiago Adolfo Vio1, Sabrina Soledad García1, María Lina Galar1, Pamela Bernabéu1, Mariana Garbi2,3, Pedro Balatti4, Aníbal Lodeiro5, Maria Flavia Luna1. (1) Laboratorio de Microorganismos de Aplicación en Agricultura, CONICET La Plata - Universidad Nacional de La Plata. CIC-PBA, Centro de Investigación y Desarrollo en Fermentaciones Industriales (2) Facultad de Cs. Agrarias y Forestales, Universidad Nacional de La Plata (3) Universidad Nacional de Luján (4) Centro de Investigaciones en Fitopatología (CIDEFI) (5) Instituto de Biotecnología y Biología Molecular

Bioinputs based on Plant Growth Promoting Bacteria (PGPB) have emerged as a sustainable agricultural alternative. However, its adoption is still incipient in the Argentine horticultural area. We assessed the effect of a multispecies inoculant (Mz) on lettuce var. Sagess in seedling and productive stage in two experimental fields:I ( ) EE-J.H. and (II) EE-Gorina, La Plata (Argentina). Mz was formulated with 4 PGPB: Azospirillum brasilense Az39 (Az), Bacillus subtilis Dm-B10 (Ba) Gluconacetobacter diazotrophicus PAL-5 (Gl) and Pseudomonas fluorescens (Ps) (108-109 CFU ml-1), using equal volumes of each one. Mz was applied at sowing (S), transplant (T) and both times (ST), and each bacterium was applied individually at ST, adding 1 ml per 10 ml of substrate. The presence of the inoculated bacteria was determined at 20 days post inoculation in seedlings with Mz, detecting 104, 105 and 106 CFU g-1 of root for Ba, Gl, Ps, respectively. Az could not be identified by the used methodology. The aerial and root dry weight of inoculated seedlings significantly increased compared to the non-inoculated ones: 45%, 32% and 28% on average for Mz, Ba and Gl, respectively. The commercial fresh weight of inoculated plant was 38.5% significantly higher in Mz (Mz-S in I and Mz-S and Mz-SyT in II) compared to the non-inoculated ones. Gl was the only individually inoculated bacteria that significantly increased in 27% the commercial fresh weight per plant compared to the non-inoculated treatment. In the evaluated parameters, the multispecies inoculant achieved a greater effect regarding to the individually inoculated microorganisms.

363 The gut microbiome of the vector Lutzomyia evansi

El microbioma intestinal del vector Lutzomyia evansi

RAFAEL JOSE VIVERO, Sandra I Uribe1, Gloria Cadavid-Restrepo2, Claudia X Moreno Herrera2, Howard Junca3. (1) Antioquia, Ciencias, Universidad Nacional de Colombia sede Medellin (2) Ciencias, Biociencias, Universidad Nacional de Colombia Sede Medellin (3) Ecogenomics & Holobionts, Microbiomas Foundation

Lu. evansi, is an insect vector recognized for the transmission of parasites causing visceral and cutaneous leishmaniasis in rural and urban environments of the caribbean coast of Colombia. In this study, we investigated the bacterial microbiome from digestive tracts of Lu. evansi adults using 16S rRNA gene amplicon high throughput sequencing (Illumina MiSeq). The samples were collected at two locations with high incidence of the disease in humans: peri-urban and selvatic ecosystems from the department of Sucre, Colombia. High quality reads of V4 region of 16S rRNA gene were obtained and clustered into 1,762 OTUs with 97% similarity. Regarding eubacterial diversity, 14 bacterial phyla and 2 new candidate phyla were found to be consistently associated with the gut microbiome content. Proteobacteria, Firmicutes, and Bacteroidetes were the most abundant phyla in all the samples and the core microbiome was particularly dominated by Methylobacterium genus. The presence of OTUs of Oxalabacteraceae and Staphylococcus in Lu. evansi, is also very remarkable, mainly in males and unfed females. As a remarkable feature, OTUs classified as Wolbachia spp. were found abundant on peri-urban ecosystem samples, in adult male (OTUs n= 776) and unfed female (OTUs n= 324). Furthermore, our results provide evidence of OTUs classified as Cardinium endosymbiont in higher relative abundance with respect to Wolbachia. Therefore, this finding could have potential and significance for biological control design. Cardinium is also vertically transmitted to progeny but rarely show co- speciation with the host.

Grupo de Microbiodiversidad y Bioprospección, Laboratorio de Biología Celular y Molecular, Universidad Nacional de Colombia sede Medellín.

364 Extracurricular professional training in Environmental Biotechnology

Formación continua: experiencias docentes extracurriculares en Biotecnología Ambiental

Natalia I. Martínez1, Silvana B. Basack2, Silvana A. Ramírez2, Diana Lia Vullo3,2. (1) INEXBI S.R.L. Soluciones Biotecnológicas para la Industria, Buenos Aires, Argentina (2) Área Química Ambiental, Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires, Argentina (3) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)

Los cursos de formación continua son una herramienta pedagógica que la Universidad Nacional de General Sarmiento ofrece desde sus diferentes áreas docentes con el objeto de transferir el conocimiento al sector productivo. El Área Química Ambiental desarrolló cursos extracurriculares dirigidos a la capacitación profesional de estudiantes avanzados o graduados recientes en Tecnicatura Superior en Química, Ingeniería Química y Licenciatura en Ecología. Esta capacitación se ofreció con el objeto de efectuar un entrenamiento específico en el desarrollo de nuevas tecnologías de tratamiento biológico de efluentes provenientes de la industria farmacéutica con el seguimiento de su eficiencia mediante el análisis de sus parámetros fisicoquímicos y biológicos, acorde con la normativa internacional. El tratamiento de efluentes es tema abordado desde la teoría en el plan de estudios, por lo que el trabajo propuesto complementa la formación experimental de las carreras. De esta manera se generaron nuevas habilidades en el manejo de técnicas en microbiología yde análisis químico cuantitativo, diseño de sistemas de cultivo y desarrollo de biorreactores a escala laboratorio, así como también búsqueda de normativas vigentes. Los participantes prepararon sus protocolos de trabajo, evaluaron las metodologías propuestas y realizaron en laboratorio simulaciones de biotratamientos para implementar mejoras en el funcionamiento de las plantas de tratamiento a partir de resultados propios. Se generaron espacios de discusión y se los evaluó mediante el seguimiento de sus respectivos cuadernos de laboratorio de uso rutinario en su actividad profesional futura y finalmente con un informe final amodode presentación oral.

Este trabajo fue financiado por la Universidad Nacional de General Sarmiento y la empresa INEXBI S.R.L. Soluciones Biotecnológicas para la Industria.

365 Fleas (Ctenocephalides felis) raised in a laboratory colony present a stable core microbiota predominated by staphylococcal species

Las pulgas (Ctenochalides felieps) criadas en una colonia de laboratorio presentan una microbiota estable predominante por especies de estafilococos coagulasa-negativos

Tatiana Werneck1, Douglas McIntosh1. (1) Departamento De Parasitologia Animal, Universidade Federal Rural Do Rio De Janeiro, Universidade Federal Rural Do Rio De Janeiro

The flea (Ctenocephalides felis) is the principal ectoparasite of dogs and cats worldwide acting as a vector of zoonotic pathogens including Rickettsia felis and Bartonella. The diversity of host associated microbes and their interactions within their hosts, including arthropods, are fundamental to the ecological functions within those communities and may contribute to host evolution. Moreover, symbiotic interactions may influence the transmissions of zoonotic pathogens, via effects upon vectoral competence. Knowledge of the microbiota of vectors has been used to develop novel approaches for control based on the concept of microbiota manipulation. A key component in this strategy is the presence of a stable/core microbiota. The present study characterized the stability, over seven years, of the cultivable microbiota of a laboratory colony of C. felis. Bacteria associated with different life stages were cultured and identified by sequencing of the gene encoding 16S ribosomal RNA. Cultures were characterized for resistance to antibiotics and were screened for the presence of lysogenic phages. Each of the different life stages presented a unique microbiota, however a core component of all samples were members of the genus Staphylococcus, with some demonstrating multiple-drug resistant phenotypes. Analysis of phage carriage is on-going. The constant presence of the same species of Staphylococcus, in multiple life stages, suggests they are essential components of the microbiota and by implication of the biology of the fleas. Future research will examine the effects of manipulating the core microbiome as the first step in the development of novel strategies for infestation control.

CAPES

366 Self-organized Patterns from a Synthetic Genetic Oscillator in Bacterial Colonies

Patrones auto-organizados de un oscilador genético sintético en colonias bacterianas

Guillermo Yanez1, Gonzalo Vidal1, Macarena Muñoz1, Sofía Figueroa1, Timothy J. Rudge1. (1) Departamento de Ingeniería Química y Bioprocesos, Ingeniería, Pontificia Universidad Católica de Chile

The most common lifestyle in bacteria is multicellular communities called biofilms. Oscillations are observed in all types of cell populations from the simplest to the most complex, including biofilms. Here we present a theoretical study of oscillator dynamics in growing cell populations, using a dynamical gene network system of 3 repressors in a loop and simple bacterial colonies as model systems. We show that the combination of growth and gene circuit dynamics gives rise to emergent travelling waves in self-organized ring patterns in bacterial colonies. Tracking the development of fluorescence-labeled cellular domains, with dilution due to growth we observed the emergence of travelling waves in the form of periodic ring patterns. As we increased the growth rate, gene expression decreased due to faster dilution. The speed of travelling waves increased as the growth rate was increased. When we simulated oscillator colonies with no dilution due to growth, we observed synchronized oscillation of the whole colony. We also found a simple emergent linear relation between the average wavelength of travelling waves and growth rate; the higher the growth rate, the lower the wavelength of the traveling waves. These results demonstrate that populations of relatively simple bacterial cells can possess emergent spatio-temporal organization due to the dynamical behaviour of an oscillatory gene circuit. This may have important implications for understanding the dynamics of growing biofilms.

This project was supported by Fondecyt Iniciacion 11161046, awarded to Tim Rudge.

367 Degradation of sinking copepods: to explore their importance for N cycling in oxygen depleted waters

Degradación de carcasas de copépodos: explorando la comunidad bacteriana y su importancia para el ciclo del N en aguas deficientes de oxígeno

Sonia Yanez1, Pamela Hidalgo1, Nicole Trefault2, Osvaldo Ulloa1, Rodrigo De La Iglesia3. (1) Departamento de Oceanografía, Instituto Milenio de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Instituto Milenio de Oceanografía, Universidad de Concepción (2) GEMA Center for Genomics, Ecology & Environment, Universidad Mayor (3) Department of Molecular Genetics and Microbiology, Pontifica Universidad Católica de Chile (Sponsored by Osvaldo Ulloa)

Marine copepods form one of the most abundant mesozooplankton groups in the oceans provide favourable surface for bacterial attachment.Thus, in pelagic ecosystems, copepods represent vastly abundant “microbial hotspots” with unique biogeochemical features. By the use of laboratory experiments, we followed the course of carcass decomposition of the copepod Acartia tonsa. In oxic conditions, copepod bodies began to degrade rapidly and continued to do so during 18 h. Between 24 ̶ 30 h later, it showed a gradual increase, towards the last 6 h of incubation, carcasses were degraded at a ~ 20% of total copepod bodies. In contrast, the decomposition process was much slower in the anoxic conditions. During the first 18 hours decomposition process shows an increase of >50% towards the 24 hours, which was even greater and higher during the last 6 hours, reaching degradation values similar to those observed in oxygenated water. Using Illumina sequencing of the 16S rRNA gene, we followed the changes on members of the bacterial community during the carcasses decomposition of A. tonsa. Results indicated that A. tonsa carcass was mainly dominated by Verrucomicrobiaceae and Rhodobacteraceae in oxic conditions; whereas Vibrionaceae and Rhodobacteraceae dominated A. tonsa carcass in anoxic conditions. The denitrification associated genes, nirK and nosZ, were detected increasingly trough time under anoxic conditions, mainly associated with the late stage of decomposition. Thus, the functioning of these carcasses as pelagic hotspots for bacterial decomposition may have implications in nitrogen cycling via denitrification.

This work was supported by Millennium Institute of Oceanography ICM 120019. Sonia Yañez was supported by the Scholarship of CONICYT-PCHA/Doctorado Nacional/2013-21130213.

368 Bacalar Lagoon: Spatial study of bacterial diversity in microbialite communities and its relationship with environmental conditions

Laguna de Bacalar: Estudio espacial de la diversidad bacteriana en comunidades de microbialitos y su relación con las condiciones ambientales

Alfredo Yanez-Montalvo2,1, Hernández Héctor1, Selene Gómez2, Luisa Falcón2. (1) Departamento de Sistemática y Ecología Acuática, El Colegio de la Frontera Sur, Quintana Roo, México 77014 (2) Laboratorio de Ecología Bacteriana, Universidad Nacional Autónoma de México, PCTY, Yucatán, México 97302

Los microbialitos son comunidades bacterianas sésiles, distribuidas en pocas regiones del mundo, que representan símiles modernos de las formas de vida más antiguas, los estromatolitos (>3,500 MYA). Laguna de Bacalar, en México, es el sitio con la mayor presencia de microbialitos de agua dulce en el mundo. Este trabajo realizó la exploración espacial de los microbialitos, para entender si existe una sola comunidad bacteriana o si presenta cambios a nivel espacial, por último, comprender qué parámetros condicionan la estructura de las comunidades. Metodológicamente, el trabajo consistió en georreferenciar los microbialitos en laguna Bacalar. Se colectaron muestras de agua para análisis de nutrientes y muestras de microbialitos. Se usó un protocolo para secuenciación de la región V4 del gen 16S SSU en IIIumina Mi-Seq-250 (Caporaso et al. 2011). El análisis de datos se realizó en QIIME versión 2.16.9, y los estadísticos en R. Los resultados indican la presencia de arrecifes de microbialitos en toda la laguna. Encontramos dos comunidades filogenéticamente diferentes, denominadas Norte y Sur. En la estructura de la comunidad participan principalmente Cianobacterias, Bacteriodetes, Plantomycetes, Proteobacteria, Verrucromicobia, Firmicutes y Chloroflexi. El Norte, correlacionado con a la conductividad, contiene la mayor diversidad bacteriana de los microbialitos. En el Sur, existe una menor diversidad y se correlaciona a bicarbonatos, amonio y nitratos. La diferencia entre los grupos se asocia a la afectación de la calidad del agua por una fuerte presión antropogénica (agricultura, lixiviados de vertederos, falta de infraestructura de tratamientos de agua domésticas y el turismo intensivo).

Este proyecto fue financiado con los recursos de SEP CONACYT254962 (LIF).

369 Characterization of rhizobacteria isolated from Salar de Huasco (Taparacá Region, Chile), a poly- extreme environment in the Chilean Altiplano

Caracterización de rizobacterias aisladas desde el Salar de Huasco (Región de Taparacá, Chile), un ambiente poli-extremo en el altiplano chileno

Natali Zamora 1, Rodolfo Paredes1, Martha Hengst2, Sara Cuadros-Orellana3, Verónica Molina4, Cristina Dorador5, Carolina Yáñez1. (1) Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica De Valparaíso (2) Laboratorio de Ecología Molecular y Microbiología Aplicada, Departamento de Ciencias Farmacéuticas, Universidad Católica del Norte (3) Centro de Biotecnología de los Recursos Naturales, Facultad de Ciencias Agrarias y Forestales, Universidad Católica del Maule (4) Laboratorio Observatorio de Ecología Microbiana, Departamento de Biología, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha de Ciencias de La Educación (5) Laboratorio de Complejidad Microbiana y Ecología Funcional, Universidad de Antofagasta

El salar del Huascoes un humedal ubicado en la zona altiplánica de la Región de Tarapacá (20°15S - 68°50W) a unos 3800 m.s.n.m. El salar se compone de cuerpos de agua con características salinas y dulces que albergan una gran diversidad microbiana. Sin embargo, poco se ha explorado sobre las bacterias que colonizan suelos y rizósferas. El objetivo de este estudio fue caracterizar las rizobacterias y las comunidades bacterianas presentes en la rizósfera de plantas provenientes de dos sitios diferentes del Salar de Huasco: H0 (vega salina) y H3 (bofedal). El aislamiento de las rizobacterias se realizó en agar marino suplementado con soluciones de tallos y hojas de las plantas recolectadas en cada sitio (teabags). Se obtuvo un total de 76 aislados. La genotipificación mediante ARDRA reveló 34 ribotipos diferentes entre las bacterias obtenidas. Mediante la secuenciación del gen 16S rRNA se logró determinar que las cepas de la estación H3 se afilian a los génerosPseudomonas , Exiguobacterium, Staphylococcus, Pseudoalteromonas, Halomonas, Bacillus y Aeromonas, mientras que las de la estación H0 se asocian a Bacillus, Halomonas, Aliidiomarina y Halobacillus. El análisis de las comunidades bacterianas fue realizado mediante 16S rRNA-DGGE, observándose comunidades heterogéneas entre la técnica de aislamiento por teabags y las estaciones analizadas en el estudio. En conclusión, la rizósfera de plantas altiplánicas alberga comunidades bacterianas altamente diversas. Representan un reservorio importante de microorganismos que podrían poseer mecanismos de promoción de crecimiento vegetal aplicables a suelos con alto stress hídrico y salino, a explorar próximamente.

FONDECYT 1181773; DI PUCV Consolidado 039.367/2019.

370 Genome-mining of chilean marine Streptomyces unveil a vast production capability and specific adaptation features.

Minería genómica de Streptomyces marinas chilenas revela una amplia capacidad productina y caracterícas adaptativas específicas.

Leonardo Zamora-Leiva1, Ricardo Valencia1, Agustina Undabarrena1, Francisco Barona-Gómez2, Beatriz Cámara1. (1) Departamento de Química , Centro de Biotecnología Dr. Daniel Alkalay Lowitt, Universidad Técnica Federico Santa María (2) Unidad de Genómica Avanzada, Evolution of Metabolic Diversity Laboratory, Cinvestav-IPN

Novel antimicrobial compounds are a major need. The appearance of multi-resistant bacterial pathogens is a reality that hospitals worldwide must face on a daily basis. In addition, after the golden age of antibiotics we are facing the high re-discovery rates of the same compounds, leading us into a dangerous position that even the World Health Organization catalogued as a global crisis. To contribute to knowledge for dealing with this problem, our research group have collected marine samples from the Chilean coastline for the search of actinobacterial strains with antibiotic activity. These strains present a wide phylogenetic distribution, showing an example of the extensive biodiversity of the Chilean marine environment. To unlock the true biosynthetic potential of these bacteria, the complete genome of 29 Streptomyces strains were sequenced using a combination of Illumina and PacBio technologies for mining their Biosynthetic Gene Clusters (BGCs), which are groups of genes that together synthesize for specialized metabolites. Genomes presented an average of 8,0 Mbp in length, 72 % of G+C content and approximately 20 BGCs per strain, involved in the synthesis of several specialized metabolites (e.g., non-ribosomal peptides, polyketides, ectoines, lanthipeptides, siderophores), according to predictions using antiSMASH v5.0 software. Predicted results were complemented with the utilization of Evomining, a software less rigorous than antiSMASH, wich is capable of finding several putative BGCs not yet characterized, thus expanding the possibility to find novel biosynthetic pathways and their congener compounds.

Beca CONICYT Doctorado N° 21180908, FONDECYT Regular N° 1171555, Conicyt PIA ACT172128.

371 Marine Streptomyces from Chilean coasts: a prospective source for the discovery of compounds against pathogenic fish oomycete Saprolegnia parasitica

Streptomyces marinas de las costas chilenas: una fuente prospectiva para el descubrimiento de compuestos contra el oomiceto patógeno de peces Saprolegnia parasitica

Nicolás Zamorano1, Néstor Serna1, Iván Montenegro2, Beatriz Cámara1. (1) Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Centro de Biotecnología Daniel Alkalay Lowitt, Departamento de Quimica, Universidad Técnica Federico Santa María (2) Escuela de Obstetricia y Puericultura, Medicina, Universidad de Valparaíso

Chile is the second largest producer of salmon worldwide, with exports of around US $ 4,000 million.These fish are prone to infection by various pathogens, includingSaprolegnia parasitica, an oomycete that generates losses of up to 10% of annual production.A series of compounds have been used to control this pathogen, however, none of them has given a solution to the problem. The new compounds are of great importance to the salmon industry. In this context, bacteria of the genus Streptomyces have been studied for producing various compounds with antimicrobial properties. Our working group has a collection of Streptomyces isolated from different marine environments along the coast of Chile.In this work, the capacity of these strains against Saprolegnia parasitica was evaluated. Initially, 29 streptomycete strains were plated on agar plates using 5 different culture media (ISP1-1/ASW, ISP-2/ASW, R5A, ISP-1, ISP-2) and the anti-saprolegnia activity was evaluated by an antagonism assay for up to 7 days. Five selected strains were then cultured that showed activity in liquid media. Extraction was carried out with ethyl acetate (EtOAc) and the effect of the extracts was evaluated by the agar diffusion method at a concentration of 5 mg/mL. The results show that strains isolated from Rapa Nui and cultured in ISP-2 culture medium, showed activity against Saprolegnia. In conclusion, the metabolites produced by the marine Streptomyces from Rapa Nui are presented as potential candidates to generate new alternatives against the fish pathogen Saprolegnia parasitica.

Fondecyt regular N°1171555 (BC), Proyecto Anillo ACT172128 (BC), DGIIP Beca Magíster USM (NZ)

372 The influence of different heavy metals concentrations on Sulfate-reducing bacteria enrichments using sediment of a port area as inoculum

Influencia de la concentración de diferentes metales pesados sobre el enriquecimiento de bacterias sulfato-reductoras, utilizando sedimentos de un área portuaria como inoculo

Bruna Zampieri1, Brucha Gunther2, Sanchèz-Andrea Irene3, Fernandes Cardoso De Oliveira Ana Julia4. (1) Bioquímica e Microbiologia, Universidade Estadual Paulista”Júlio de Mesquita Filho” (2) Universidade Federal de Alfenas (3) Wageningen University and Research (4) Universidade Estadual Paulista”Júlio de Mesquita Filho”

Sulfate-reducing bacteria (SRB) are a group of anaerobic bacteria that have great potential for bioremediation studies of areas contaminated with heavy metals. The microbial community is sensitive to toxicity caused and generally, SRB’s activity decreased. Thus, to potentiate this use it is still necessary to know which groups of sulfate-reducing bacteria are actually more resistant to metals. Port areas are known around the world as areas that present metals concentrations above acceptable levels, being areas where microbial communities have been exposed by this type of contamination for a long time and can be an important inoculum for isolation of metal-resistant SRB. In this way, the objective of the present study was to analyze how heavy metals influence the community of sulfate-reducing bacteria present in the sediment of a port area and to isolate resistant species that can be further utilized in biotechnological applications. The enrichments demonstrated the microbial activity of an SRB community decreased with the increase of all heavy metals tested. At the end of the experiment, the community was dominated by Desulfovibrio sp, but it was also found Desulfobulbos sp and Thermodesulfovibrio sp that were capable of precipitating about 80% of the metals with initial concentrations of 6.0 mM Zn; 8.0mM Cr, 0.3mM Cd, and 1.3mM Cu. Cu was the metal that presented more toxicity for the SRB and the community was more resistant to Zn. At the end of the study, a new specie of Desulfovibrio capable to resist to high levels of heavy metals was isolated.

Coordination for the Improvement of Higher Education Personnel (CAPES)

373 SPONSORS

374 INDEX

Allen Herre Edward 29 A Almaguer Chávez Michel 312 Abanto Michel Francisco 97 Almendras Katerin 117, 352 Abarca Juan 252 Alonso Cecilia 47, 203, 205 Acinas Silvia G. 221 Alonso Daniel 118, 195 Acosta Eduardo 226 Alvarado Wilber Alexander 119 Acosta Grinok Mauricio 44 Alvarado-Mesén Javier 315 Acosta-González Alejandro 13, 22 Alvarez Irene 31 Acuña Carla Angélica 98 Álvarez María Ignacia Acuña Daniel 74 Álvarez Mario 229 Acuña Jacquelinne Jovanka 71, 99, 100, 147, 296 Alvarez-Santullano Natalia Sofía 120 Acuña-Rodriguez Ian S 137 Alves Isabel Martins Sabino 331 Adell Aiko D. 101, 102, 103 Alviz-Gazitúa Pablo 120, 181 Agnello Ana Carolina 104 Amann Rudolf 47, 83 Agnolucci Monica 356 Amaral João Henrique 54 Aguayo Paulina 105 Ambrosini Roberto 23 Aguila Patricia Isabel 107, 237 Amenabar Maximiliano 48, 344 Aguila Blanca 106, 357 Amézquita Adolfo 22 Aguilar Pablo 108, 355 Andrade Derly 121, 277 Aguilar Polette 45 Andrade Hidalgo Daniel 234 Aguilar Silvana 109 Andrade Santiago 64 Aguilar-Muñoz Polette 73 Andrade Vanessa Da Costa 122, 254, 335 Aguilar-Rangel Eduardo Javier 110 Andrews Barbara 167, 239 Águila-Salgado Bernardo 111 Angelis Dejanira De Franceschi 254 Aguilera Lorgio 337 Ann Gregory 32 Aksenov Alexander 57 Antelo Verónica 123 Alarcón Jaime 112 Antúnez Karina 124 Alarcón-Schumacher Tomás 144, 159 Anyi Hu 199 Alba Jeanne 158, 193 Anzola Juan Manuel 185 Albarracín Virginia Helena 118, 195 Añon Guillermo 124 Alcaman Maria Estrella 46, 159 Apaza-Castillo Gladys A. 125 Alcántara-Durán Jaime 205 Aran Pablo 226 Alcántara-Hernández Rocio Jetzabel 110, 111 Arancibia Gabriela 278 Alcayaga Valezka Del Pilar 69, 113 Aranda María Catalina 126, 127 Alcorta Jaime Andres 114 Aravena Camila Paulina 128 Aldunate Montserrat 68 Aravena Rocío Melissa 129 Alfaro Fernando 64 Araya Macarena 99, 100 Alfaro Juan Felipe 115 Araya Marcelo 130, 197, 207 Alfaro Pablo 116, 216 Araya-Figueroa Aníbal 101

375 Arboleda Clara 284 Barría Carla 101, 102, 157 Arce Manuel 131 Barría Stephanie 135 Arciénaga Montserrat 132 Barrientos Leticia 275, 292, 311, 316, 317 Arias Dayana 133, 297 Barros Daniel 169 Arisan Dilanaz 153, 217 Barros Germán Gustavo 139 Armasu Lavinia 127 Barry K 27 Arredondo Daniela 124 Basack Silvana Beatriz 262, 365 Asenjo Juan 167, 239 Basso Néstor Guillermo 51, 109 Asselta Fernanda 182 Bastias Roberto 131 Astini Ricardo 260 Bastidas Marcela 49, 80, 353 Astorga Marcia Carolina 134 Basulto Rosa 265 Astorga Maria Soledad 73 Becerra Absalón Itzel 111 Atwill Robert 101 Bekele E 27 Auger Pierre-amaël 270 Belmonte Marisol 347 Avalos Vladimir 135, 173, 198, 301 Bendall Matthew 168 Avendaño Priscilla 166 Berge Matthieu 67 Avendaño-Herrera. R. 178 Bernabéu Pamela Romina 362, 363 Ávila Kyria 29 Berrios Pablo 138 Avio Luciano 356 Bertagnolly Anthony 211 Azzoni Roberto Sergio 23 Bertilsson Stefan 54 Bertoglio Florencia 84 B Besoain Ximena 346 Backhaus T. 218 Bignon Eduardo 50 Baena Sandra 148 Blamey Jenny 344 Bailey Jake 77 Blum Thorsten 67 Baker-Austin Craig 97 Boehmwald Freddy 112 Balagué Vanessa 75, 183 Bol Roland 87 Balatti Pedro 363 Bonacci Martín 139 Baldani José Ivo 250 Borges Garcia Carlos Alexandre 56 Balseiro Esteban 49, 80, 318 Bórquez Jorge 234 Barahona Francisco 14, 145, 371, 357 Borzutzky Arturo 152 Barahona Sergio 87 Bouget Francois-yves 15, 64 Barbosa Eder Alves 51 Bovio Patricia 140, 224, 281 Barbosa Olga 314 Boya Cristopher A. 29 Barcelos Clara 72 Boyd Eric 48 Barra Paula 139 Brack W. 218 Barra-Sanhueza Bárbara 136, 177 Bravo Florencia 141 Barraza-Cepeda Claudia 337 Bravo Guillermo 142, 354 Barrera Andrea 137 Brenes-Guillén Laura 143 Barrera Cristían 101 Briceño Isabel 309 Barret Maialen 73 Bruna Nicolás 85, 348

376 Buscaglia Marianne 144 Casanova María Angélica 321 Busche Tobias 322 Casas-Vargas Julian Camilo 149 Bustingorry Jose 293 Castañeda Luis 150 Bustos-Diaz Edder Daniel 145 Castellanos Rodríguez Diana 361 Castillo Daniel 151 C Castillo Francisca 152 Cabalín Carolina 152 Castillo Loriana 309 Cabezas Da Rosa Angela 140, 351 Castillo Villamizar Genis Andres 287 Cabral Anderson S. 30 Castillo Wilson 321 Cabrera María De Los Ángeles 85 Castillo Yannira 173 Cabrol Léa 45, 73, 225, 320 Castro Camila 231 Cabrol Nathalie 339 Castro Jean Franco 239 Cáceres Jeimmy 93 Castro Matias 153, 217 Cadavid-Restrepo Gloria 364 Castro-Nallar Eduardo 81, 85, 87, 94, 112, 154, 155, 339 Caipo Marisa 103 Castro-Severyn Juan 155 Calabi Marcela 212 Catalán Natalia 306 Calabrano Pedro 189 Cayupe Bernardita 279 Calle Natalia 73 Cea Daniela 101 Calliari Danilo 47 Cecotti Martina 156 Cámara Herrera Beatriz 94, 162, 204, 268, 323, 371, Cedeño Marjorie 29 372 Cerpa Waldo 209 Cameron Henry 135, 249 Céspedes Martín 228 Campelo Vilardi Argentino Isabella 319 Cevidanes Aitor 52, 157 Campos Jose Luis 347 Chala Andres 180 Campos Marco Antonio 147 Chamy Rolando 45, 73, 186, 225 Campos Víctor 105, 141, 295 Chan Chia Sing 361 Cancelarich Natalia Lorena 51, 109 Chan Kok-gan 361 Cannavan Fabiana De Souza 55 Chapleur Olivier 186 Cantillo González Angela 148 Chiacharini Patricia 217 Cárdenas César 283 Chichon Javier 121 Cárdenas Constanza 237 Chirife Andrea D. 157 Cardoso Elke Jbn 259 Chong Guillermo 166, 339 Careaga Valeria 361 Chong Robles Jennifers 72, 327 Carminato Luiza 288 Choque Alessandra 87 Caro Castro Junior 158, 193, 313 Chris Bowler 32 Carrara Virginia 210 Christoph Tebbe 212 Carrasco Héctor 217 Chumpitaz Astrid Carolina 158, 193 Carrazana Dulemys 266 Cibrián-Jaramillo Angélica Carrera Paula 146 Cifuentes Jerónimo 46, 159, 321 Carú Margarita 117, 263, 269, 352 Cifuentes Paulina 160, 191 Carvajal Andrea 268 Cillero Javier Ignacio 161 Carvajal Marcela 257

377 Cisternas Luis A 133, 297 Claverías Ramos Fernanda Paz 162 D Da Conceição Jesus Ederson 214 Colman Déborah 163, 361 Da Silva Junior Eduardo 300 Colomban De Vargas 32 Dabanch Jeannette 309 Colón-Cruz Ángela M. 58 Dagan Tal 16 Concha Christopher 337 Dahech Pablo 169 Conde Martínez Natalia 13 Daille Leslie K. 53, 128 Conde Renaud 308 Damien Eveillard 32 Conrad Ralf 212 Daniel Rolf 287 Conteau Delphine 186 Daniele Iudicone 32 Contreras Manuel 20, 291 De La Iglesia Rodrigo 53, 64, 105, 128, 284, 368 Conway Mike 303 De La Sovera Victoria 170 Coppotelli Bibiana M 82, 185, 227, 238 De Melo Michaela 54 Cordoba Alexander 93 De Oliveira Braga Lucia Elaine 62 Coria Silvia Herminda 163 De Souza Leandro Fonseca 55 Cornejo Diego 188, 355 Deangelis Kristen 17, 59 Cornejo Marcela 60, 81, 98, 270, 285, 291 Del Busso Zampieri Bruna 56, 247, 248 Corona Andrea 164 Del Panno María Teresa 104, 171, 174 Corsetti Frank 77 Delong Edward F. 18 Cortes Johanna Alejandra 69, 152, 165 Demergasso Cecilia 44, 166, 339 Cortés Mayra 166 Derrien Muriel 172 Cortés-Albayay Carlos 167 Descy Jean Pierre 183 Cossío-Bayúgar Raquel 308 Devercelli Melina 213 Costa Andrade Vanessa 247, 248 Di Cataldo Sophia 52, 157 Costa José 74 Di Clemente Natalia A. 171 Costa Juliana 182 Díaz Cárdenas Carolina 148 Cotillard Aurélie 172 Diaz Constanza 101, 102 Covarrubias Briceida 72 Diaz Edgar 57, 172 Coyle Nicola 317 Diaz Mac-Adoo Daniela 173 Crandall Keith 168 Díaz-Díaz Lymarie M. 58 Cristi Antonia 283 Dib Julián Rafael 287 Croci Carolina 300 Diego Taha 278 Cruz Carmen 253 Diez Beatriz 46, 63, 114, 143, 144, 159, 206, 208, 321, Cuadros Sara 69, 370 338, 358 Cueto Gerardo 293 Diez María Cristina 175 Cumsille Andres 94 Diolaiuti Guglielmina 23 Curutchet Gustavo 351 Diovisalvi Nadia 293 Custódio Márcio Reis 210, 288 Dodji Soviadan 32 Domeignoz Luiz 59 Domínguez Laritza 31, 264, 266 Dominici Lina Edith 174

378 Donati Edgardo 132, 217, 231, 232, 235, 246 Donati Valentina 151 F Fabiano Elena 300 Donn Mj 27 Fabien Lombard 32 D’onofrio Claudio 356 Falcón Luisa 79, 111, 369 Donoso Raúl 192, 197 Fantinatti Garboggini Fabiana 62 Donoso-Piñol Pamela Paulina 175 Farias Laura 46 Dorador Cristina Inés 60, 69, 165, 167, 179, 188, 198, 209, 222, 226, 236, 253, 301, 326, 355, 370 Farías Maria Eugenia 20, 118, 195, 287, 334 Dorochesi Flavia 176 Farkas Carlos 228 Dorrestein Pieter 57 Federici Fernan 274, 332 Dorta Fernando 257 Feitosa Yara 182 Duarte Carlos M. 221 Fermani Paulina 183 Duarte Escalante Esperanza 312 Fernandes Cardoso De Oliveira Ana Júlia 56, 247, 248, 373 Dumont Marc G. 70, 212 Fernández Ana 61 Duran Paola 71 Fernandez Camila 256, 345 Durán Roberto E. 136, 176, 177, 237, 302 Fernandez Diana 173 Durrer Ademir 259 Fernández Erika 116 Fernandez Guillermo 261 E Fernández Scavino Ana 286 E. Alvarado Guillermo 143 Fernández Sofía 184 Eastman Guillermo 196 Ferrada Pablo 258, 324 Echeverría Alex 166 Ferrer Alonso 206 Echeverría-Bugueño M., 178 Ferrera Isabel 21 Edward R. B. Moore 38 Festa Sabrina 185, 227 Eissler Yoanna 60, 69, 179 Feyhl-Buska Jayme 77 Encalada Olga 44, 166 Fiaschi Grazia 356 Erijman L. 140 Fiatt Fiorella 252 Erik Karsenti 32 Fica Alberto 309 Erira Tupaz Alveiro 180 Figueroa Sofía 367 Escalona Mauricio 258 Filipa Godoy-vitorino 342 Escaray Roberto 293 Fiore Marli F. 125, 182 Escobar Laura A. 22 Fiorentino Susana 148 Escudero-González Lorena 44, 166 Flechas Sandra Victoria 22 Espejo Romilio 19 Flores Clavo Rene 62 Esperón Fernando 52, 157 Flores Javiera 296 Espinoza-Tofalos Anna 181 Flórez Olarte Diego León 343 Estrada-Bonilla Gérman Andrés 259 Fontes-Noronha Melline 81 Estrada-De Los Santos Paulina 110 Ford Charlotte 97 Etchebehere Claudia 140, 170, 224, 281 Formento Norma 139 Etcheverry Miriam 139 Forsberg Bruce 54 Fraga Andrea 78

379 Franchi Oscar 186, 347 García-Arrarás José E., Ph.d. 58 Francis T. Ben 83 García-Gen Santiago 224 Franco Lida Marcela 126 García-Reyes Juan Francisco 205 Franco Ramón 31, 264, 266 Garzón John 203 Franco-Cisterna Belén 187 Gasol Josep M. 75, 221, 255 Franzetti Andrea 23, 181 Gentina Juan Carlos 142 Frey S.d. 59 Gerard Emmanuelle 260 Frez Katherine 188 Gérikas Ribeiro Catherine 200 Fuchs Bernhard 83 Gerrit Voordouw 88 Fuentes Bárbara 87 Giaveno Alejandra 217 Fuentes Melizza 216 Giesecke Ricardo 345 Fuentes Sandra 113 Gil Pilar 101 Fuentes Sebastián 63 Giménez Matías 123 Fuenzalida Gonzalo 189 Giner Caterina R. 221 Fujiyoshi So 190, 243 Giovannetti Manuela 356 Glasner Benjamín 64 G Glud Ronnie N. 187 Gabal Gilberte 186 Godoy Karen 337 Gabbarini Luciano Andrés 299 Godoy Marcos 251 Gaete Alexis 107, 120 Godoy-Morán Rosa 201 Gajardo-Alister Roberto 160, 191 Godoy-Vitorino Filipa 24, 202, 341, 349, 360 Galar María Lina 363 Goh Kian Mau 361 Galaz Sandra Janet 192 Gomes Da Paixão Melo Weilan 340 Galdós Liszoe 31, 264, 266 Gomes Eldon Carlos Queres 330, 331 Galindo Cabello Nadia 158, 193, 194, 313 Gomez Fernando 260 Gallardo C. 218 Gómez Francisco 87 Gallardo Yasna 153, 217 Gómez Selene 369 Galván Fátima Silvina 195 Gonçalves Ribeiro Thiago 214 Galvez María Jesús 270, 345 Gonzáles Belén 205 Gamboa Fredy 180 González Ángela 120 Gandois Laure 73 González Belén 47 Gaona Gabriela 102 González Bernardo 161 Garabato Florencia 196, 300 González Carolina 65, 272 Gárate-Castro Carla 130, 197, 207 Gonzalez G. Susett 134 Garbi Mariana 363 González Humberto 345 Garcia Adriana 180 Gonzalez Leonardo 135 García Araya Jonathan 198 González Luis Javier 265 García Jaime 117 González María Belén 203 Garcia Maria Carolina 199, 273 Gonzalez Marianela 346 García Sabrina Soledad 362, 363 González Mauricio 107, 120 García Víctor 308, 309, 310 González Myriam 136

380 González Nemecio 31, 264 Hidalgo Pamela 368 González Raúl 266 Hinman Nancy 339 González Valentina Alejandra 204 Höfer Juan 256 González-Revello Alvaro 84 Holmes David S. 65, 272 Gourvil Priscillia 200 Hoyos Oladier 199 Graumann Peter 92 Hu Anyi 273 Greif Gonzalo 203, 205 Huamán Monica 194 Griffero Luciana 47, 205 Huber Paula 90, 213, 280, 293 Grimolizzi Celeste 351 Hudson Theresa 303 Groot Helena 149 Huerta Fernanda 152 Grossolli Gálvez Jonnathan 206 Hurtado Felipe 50 Guajardo Mauricio 130, 197, 207 Guajardo-Leiva Sergio 144, 154, 208 I Guerrero L. 140 Ibañez Cristian 337 Guiliani Nicolás 44, 181 Igne Rocha Fernando 214 Gunga Hanns-christian 25 Inostroza Nitza 71, 99, 100, 296 Gunther Brucha 56, 373 Inostroza P.a. 218 Gutiérrez Marcelino 29 Iraola Gregorio 123 Gutiérrez Marcelo H 66 Irene Sanchèz-andrea 373 Gutiérrez-García Karina 145 Irgang R 178 Gutzwiller Florence 154 Iriarte Andrés 300 Guzmán Daniel 116 Iriarte-Puña Maria De Las Mercedes 215, 216 Guzmán Leonardo 189 Issotta Francisco Luciano 217, 232 Guzmán Luis 126 Guzmán Sheyla 209 J Jaén-Luchoro Daniel 177 H Janaina Rigonato 32 Hagler Allen N. 30 Jara Andrea 87 Hardoim Cristiane C.p. 210, 288 Jara Carol 279 Hayoz Mathilda 67 Jaramillo Angélica 150 Héctor Hernández 369 Jeffrey Wade 69 Heimburger Lars-eric 225 Jeison David 297 Heller Maija 68 Jessen Gerdhard L. 218 Hengst Martha Brigitte 60, 69, 113, 152, 165, 179, Jesus Ederson Da Conceição 328 222, 223, 301, 370 Jiménez Aliaga Pablo 219 Henríquez Carlos 105, 211 Jiménez Gabriela 112 Henriquez Karem 165 Jiménez Javiera 92, 220 Hernández Edgardo 163, 361 Jimenez Liliana 172 Hernández Lisette 136 Jimenez Victor 258 Hernández Marcela 70, 212 Joaquin Rilling 99 Hernandez Tasco Alvaro Jose 62 John Uwe 95 Hernández-Domínguez Eduardo 308

381 Johnson Barrie D 217 Johnson Hope 77 L Lafourcade Mónica 309 Johnston Eric 294 Lago Lestón María Asunción 72, 327 Jorgensen Johanna 151 Lagomarsino Leonardo 90, 293 Jorquera Franco 257 Lagos Diego 239 Jorquera Milko 71, 99, 100, 134, 147, 296, 362 Lagos Rosalba 74 José Salvador Marcos 62 Lamilla Claudio 175 Jove Enrique Pablo 360 Lampidis Mijali 223 Juan Pierella 32 Langleib Mauricio 300 Junca Howard 364 Lara Rubén 203 Junger Pedro C. 221 Lars Stemmann 32 Junier Pilar 26, 67, 164 Latz Simone 131 Lavergne Céline 45, 73, 224, 225 K Lavin Paris 226 Kaksonen Ah 27 Layun Florencia 185, 227 Kalinowski Jörn 322 Le Gall Florence 200 Kaminek Marek 67 Lecomte Karina 261 Keeling Patrick J. 303 Ledger Thomas 161, 228, 229, 230 Keevil Charles W. 70 Lee Kang Soo 164 Keymer Juan 332 Leiva Bárbara 175 Kim Minji 102 Lencina Agustina 20, 334 Kinkel Dorothee 70 León Carla 295 Klarian Sebastián 157 León Jorge 193, 158, 194, 313 Klatt Judith 20 Leonard Guy 303 Knight Rob 57, 172 Lescano Carolina 47 Knupp Débora Farage 233 Levicán Gloria 206, 219, 298 Kolbe Allison 168 Levipan Hector 98 Konstantinos T Konstantinidis 83, 294 Lienlaf Pamela 257 Kothawala Dolly 54 Lima Maria Alejandra 217, 231, 232 Kram Karina 305, 306 Lins Philippe De Castro 233 Krauss M. 218 Liu X.j.a. 59 Krister Sundell 151 Lizama Jiménez Catherine 234 Kroff Pablo 186 Lobo-Hajdu Gisele 210 Krüger Karen 83 Lodeiro Aníbal 363 Krüger Ricardo Henrique 233 Logares Ramiro 183, 221 Kruk Carla 84, 242 Lopes Dos Santos Adriana 28, 200 Kueneman Jordan 22 López Bedogni Germán A. 235 Kuhn Gerhard 361 López Haydee 72 Kurt Daniel 20 López-Vdovenko Evangelina 29 Kurte Lenka 222 Lorca Diego 155 Kurth Daniel 287 Loyd Sean 77

382 Lozano Jean-claude 64 Martinez-Cruz Karla 73 Lozano Luis 308, 309, 310 Martínez-Romero Esperanza 91, 240, 241, 325 Luna Maria Flavia 362, 363 Martinez-Urtaza Jaime 97, 275, 316, 317 Lutts Stanley 115 Martinich María Francisca 230 Luza-Miric María Francisca 236 Martyniuk Nicolás 49, 80 Maruyama Fumito 100, 190, 243 M Másmela Mendoza Julián Esteban 244, 245 M. Martin Alberto J. 138 Massana Ramón 183, 221 Mac Cormack Walter Patricio 163, 361 Massello Francisco L. 132, 232, 235, 246 Macaya Constanza C. 237 Massonetto Mirella 247, 248, 254, 335 Macchi Marianela 82, 238 Mata M. Teresa 249 Macias-Rodríguez Lourdes Iveth 89 Matos Gustavo Feitosa 250 Madueño Laura 336 Matthew B. Sullivan 32 Magdaleno Dante 72, 327 Matute Tamara 274 Mahé Frédéric 303 Maureira Alejandro 258, 324 Maldonado Jonathan 107 Mayer Benjamin 92 Maldonado-Chaar Sergio M. 58 Mayora Gisela 213 Mandakovic Dinka 120 Mazari Hiriart Marisa 350 Manoela Brandão 32 Mazeas Laurent 186 Marani Mariela Mirta 51, 109 Mcdonald Daniel 57, 172 Marchant Francisca Andrea 239 Mcintosh Douglas 366 Marcial Silva 277 Medina Daniel A 251 Marcoleta Andrés 74 Medina Ferrer Fernando 77 Marcos Antonio Oliveira 56 Medina Freddy R 360 Marguet Emilio 194 Mejía Luis C. 29 Marie Dominique 200 Melillo J.m. 59 Marín-Paredes Roberto 91, 240, 241 Melnik Alexey 57 Marín-Vindas Carolina 75 Mena Jesús 265 Marion Gehlen 32 Mendez Katterinne N. 81, 87, 154 Marko Budinich 32 Méndez Valentina 176, 177, 237, 346 Márquez Sebastián L. 80, 85 Mendieta Micaela 116 Marrasé Cèlia 221 Mendonca-Hagler Leda 30 Martínez Gabriela 242 Mendoza Bradd 252 Martinez J.eduardo 138 Menes Rodolfo Javier 78, 304 Martínez Juan Pablo 115 Meneses Claudio 154 Martinez Kerly 76 Meneses Daniela 188, 253 Martinez Luciano 195 Mercado Ricardo Augusto 79 Martinez Miguel 160, 191 Merguizo Roberta 122, 247, 248, 254, 335 Martínez Natalia I. 365 Mestre Mireia 221, 255, 256 Martínez Saba 188 Metz Sebastian 183, 213 Martínez-Bellange Patricio 153 Meza Debora Estefania 257

383 Middelboe Mathias 151 Moreno Mario 267 Millán Javier 52, 157 Moreno Switt Andrea 103 Miller-Montgomery Sandrine 172 Moreno Velandia Carlos Andrés 244 Milner David S. 303 Moreno-Pino Mario 267 Miranda Carol 258, 324 Morgan M 27 Miranda Claudio D. 306 Mors Agustin 260 Miranda Nicolas 301 Mosquera-Corral Anuska 146 Miranda Silva Antonio Marcos 259 Moya-Beltran Ana 201, 217, 232 Miranda-Miranda Esthefan 308 Müller Marie-caroline 83 Mlewski Estela Cecilia 260, 261 Muñoz Laura 268 Modenutti Beatriz Estela 49, 80, 318, 353 Muñoz Macarena 367 Molina Cristian 126 Muñoz-Camargo Carolina 149 Molina Franck 155 Muñoz-Villagrán Claudia 206 Molina Laurence 155 Murillo Alejandro Andrés 32, 81, 270 Molina Veronica Andrea 23, 60, 69, 81, 98, 129, 165, Murillo Catalina 252 179, 222, 270, 285, 291, 301, 345, 370 Muro-Perez Gisela 89 Molina-Montenegro Marco A 137 Muster Cecilia 263, 269, 352 Monasterio Octavio 277 Monge Natacha 309 N Monrouzeau Teddy 67 Navarrete Florencia 251 Monroy Andrea Micaela 262 Navarrete Isabel Cristina 270, 285 Montecinos Alejandro 189 Navarrete Sergio A. 284 Montejano Zurita Gustavo Alberto 111 Navarro Carolan 360 Montenegro Iván 346, 372 Navarro Claudio 348 Montes De Oca-Vásquez Gabriela 333 Navarro-Cascante Valeria 271 Moore Edward R. B. 176, 177, 237 Neat Erika 69 Moore Karen 303 Neira Gonzalo 65, 272 Mora López Manuel 350 Nervi Eliana 84 Mora Maria De La Luz 71 Nesci Andrea 139 Moraga Rubén 141 Neves Elena 52 Morales Felipe 283 Nieto Esteban 82, 227 Morales María Camila 263, 269, 352 Niño Juan Pablo 199, 273 Morales Naiyulin 155 Noorlag Janneke 332 Mora-López Marielos 143 Nordelo Aylin 31, 264, 266 Morán Rolando 31, 264, 265, 266 Nouioui Imen 167 Morana Cédric 183 Novais Candido Barreto 328 Moreira Daniel Carneiro 51 Nowell David 103 Morel Isidora 64 Núñez Isaac 274 Morelli Irma Susana 82, 156, 185, 227, 238, 336 Nuñez Reynaldo 282 Moreno Andrey 180 Núñez-Montero Kattia 275, 292, 311 Moreno Gloria 180 Nüsslein Klaus 55 Moreno Herrera Claudia X 364

384 Patrick Wincker 32 O Paula Fabiana 182 Obregon Dasiel 55 Paulas Condori Licyel Lenny 215 Ochoa Susana 119 Paulas Licyel 116 Odriozola Adolfo 67 Pedrós Alió Carlos 33, 143, 159 Odriozola Mariana 280, 293 Pedrouso Alba 146 Olivares Francisca Ignacia 105, 276 Peer Bork 32 Olivares Jorge 92, 101, 277 Pellegrinetti Thierry 182 Olivares Makarena 257 Peña Hermann 81, 129, 285 Olivares Sebastian 73 Peñuela Mesa Gustavo Antonio 343 Oliveira Ana Julia Fernandes Cardoso 122, 254, 335 Pereira Emiliano 203, 205 Olivier Jaillon 32 Pereira Mora Luciana 286 Orellana Daniela 230 Pérez Luis Orlando 51, 109 Orellana Luis H. 83, 294 Perez Maria Florencia 287 Orellana Roberto Andres 98, 291, 278 Pérez-Cruz Ligia 317 Orellana Salazar Javier 215 Pérez-Donoso José Manuel 85, 348 Orlando Julieta 117, 263, 269, 294, 320, 352 Pérez-Losada Marcos 168 Ortiz Ana P. 349 Pérez-Pantoja Danilo 130, 192, 197, 207, 228 Ortiz Claudia 169, 290 Pérez-Parada Andrés 205 Ortiz-Morales Gilmary 202, 349 Pérez-Villafañe Omar A. 58 Osorio Gonzalo 309 Pérez Vilma 69, 165, 222 Osorio Hector Marcelo 279 Petry Feiler Henrique 259 Ospina-Serna Juliana 280, 293 Petryshyn Victoria 77 Ossandón Bárbara 253 Piccini Claudia 84, 242 Osses Esteban 64 Pimentel Eulogio 31, 265 Otto Rafael 259 Pino Rodríguez Nancy Johanna 343 Oyarzua Pia Karina 140, 281 Pinto Adrián 34, 252 Pistorio Mariano 362 P Pittino Francesca 23 Palacio-Rodriguez Ruben 89 Plácido Alexandra 51 Palmieri Ilona 67 Platero Raúl 196, 300 Paludo Camila Raquel 340 Plaza Cazón Josefina 132 Paneque Manuel 282 Plaza Daniel 289 Paneque Yunier 31 Pold Grace 59 Pantoja Silvio 66 Pollender André 298 Parada-Pozo Génesis 283 Pontigo Darlyng 290 Pardo-Esté Coral 155 Porte Lorena 309 Paredes Rodolfo 370 Porzionato Natalia 351 Pareja Belén 284 Poulin Elie 320 Parra Boris 160, 191 Poupin María Josefina 230 Parra-Giraldo Claudia M. 22 Powell Andy 97 Parro Victor 339

385 Pozo Francisco 291 Ridley Christina M. 88 Prado-Pano Blanca Lucía 110 Rilling Joaquín Ignacio 147, 296, 362 Probert Ian 200 Ríos Rocafull Yoania 38 Pupo Mônica T. 35 Riquelme Carlos E. 135, 173, 249 Purcarea Cristina 226 Rivas Mariella 133, 297, 324 Puzon Gj 27 Rivera Cecilia 129 Rivera Dacil 103 Q Rivera Javier Ignacio 298 Quatrini Raquel 36, 153, 217, 232 Riveros Felipe 234 Quezada Carolina Paz 85 Roberta Merguizo Chinellato 56 Quezada Rivera Jesus Josafath 89 Robledo Natalia Belén 299 Quezada-Solís Damian 292 Robles Jorge 148 Quiñones R.a. 218 Rodriguez Cecilia 196 Quiroga Maria Victoria 293 Rodriguez Constanza 339 Quispe Carolina 158, 193 Rodríguez Davydenko Sonia 312 Rodríguez Héctor 305 R Rodríguez Lorena 47 Ramaglia Andressa A. M. 288 Rodriguez Maria Cecilia 300 Ramaglia Andressa C.m. 210 Rodríguez Sánchez Janet 38 Ramirez Diego Fernando 199 Rodríguez Sebastián 301 Ramirez Rojas Adán 185 Rodríguez Varela María S. 171 Ramirez Salvador Francisco 86 Rodríguez-Castro Laura 302 Ramírez Silvana A. 365 Rodríguez-León Edwin 307 Ramírez-Camejo Luis 29 Rodríguez-Martínez Raquel 303 Ramirez-Fernandez Lia 294 Roine Elina 50 Ramirez-Flandes Salvador 68, 211, 276, 307 Rojas Flores Teresa Irene 312 Ramond Jean-baptiste 37 Rojas Johanna 74 Ramos Patricio 137 Rojas Laura Yinneth 148 Ramos Yassel 265 Rojas Marcia María 38 Raquel Quatrini 201 Rojas Maykol 129 Raschella Ariel 29 Rojas Rodrigo 306 Ravanal Javiera 295 Roldán Diego M. 78, 304 Razmilic Valeria 239 Rollins-Smith Louise 22 Reinert Laura K. 22 Romaguera Josefina 24 Reissig Mariana 90 Roman Stocker 164 Remonsellez Francisco 87, 155 Romero Francisco 155 Retamal Morales Gerardo 219 Romero Jaime 305, 306 Reyes Montes María Del Rocío 312 Romero Jaldín Ana María 215 Riano-Pachon Diego M. 125 Rosa Luiz Henrique 330, 331 Ribeiro José Roberto 30 Rosario-Meléndez Natalia 58 Richards Thomas A. 303 Rosen Michael 77

386 Rossen John 309 Sánchez-Salas Jaime 89 Rossoni Stefano 153 Sánchez-Vargas Stephanny 315 Rouws Luc Felicianus Marie 250 Sandes Laura 196, 300 Ruber Rodríguez-barreras 342 Sandoval Tito 148 Rückert Christian 322 Sanhueza Camila 309 Rudge Timothy James 274, 359, 367 Santibañez Rodrigo 138 Ruiz Daniela 161, 230 Santoro Alyson E. 303 Ruiz Paula Sofía 307 Santos Andres 97, 275, 311, 316, 317 Ruiz Quiñonez Nataly 62 Saona Luis 20 Ruiz-González Clara 75 Saparrat Mario C. N. 171 Russell Virginia 77 Sarmento Hugo 54, 183, 221 Rygh Nina 157 Sartori Melina 139 Sayes Camila 135 S Schenone Luca 318 Saavedra Claudia P 155 Schiaffino María Romina 90 Sabio García Carmen 90 Schintke Silvia 164 Sachman Bernardo 308, 309, 310 Schlömann Michael 201, 298 Sacristán Irene 52, 157 Schmidt Thomas 39 Sadowsky Michael 71 Schultz Junia 319 Sáenz-Mata Jorge 89 Schwob Guillaume 320 Saggin Júnior Orivaldo José 328 Sebastián Marta 75 Sagua Mara Inés 90 Sebatián Marta 221 Sala M Montserrat 255 Seeger Michael 23, 115, 120, 136, 142, 176, 177, 181, Salazar Cecilia 123 237, 257, 268, 278, 302, 346, 354, 356 Salazar Rodrigo 311 Seeger Pfeifer Michael 38 Salcedo-Castro Julio 291 Segura Angel 84, 242 Salgado Oscar 114, 144, 208 Segura Diego 321 Salinas Carlos 282 Sekurova Olga 322 Salinas Pamela 282 Sepulveda-Jauregui Armando 73 Sallaberry Nicole 52, 157 Serna Néstor 372 Salmond George 289 Serna-Cardona Néstor 323 Saltonstall Kristin 29 Serrano Génesis 258, 324 Salvà-Serra Francisco 176, 177, 237 Servín-Garcidueñas Luis Eduardo 91, 240, 241, 325 Sánchez Castro Daymara 38 Shapiro Russell 77 Sánchez Ileana 31, 264, 265, 266 Shelsy Cuellar 326 Sanchez Jorge 257 Shinichi Sunagawa 32 Sánchez Kenia Caridad 312 Sidón Ceseña Karla 327 Sánchez Marilin 313 Sidón Karla 72 Sanchez Roland 189, 314 Silva Andrea 126, 189, 314 Sánchez Victor 135 Silva Cleudison Gabriel Nascimento 250, 328 Sánchez-Quitian Zilpa Adriana 22 Silva Cristiane Figueira 328 Silva Daniela Roccio 329

387 Silva Eliane Maria Ribeiro 328 Tanaka Daisuke 243 Silva Francisco 309 Tapia Sofía 74 Silva Marcial 92, 220 Tapia-Cammas, D. 178 Silva Thamar Holanda 330, 331 Tapia-Torres Yunuen 240, 241 Simirgiotis Mario 234 Tarazona Ulrike 194 Simões-Araújo Jean Luiz 250 Tasca Gois Ruiz Ana Lucia 62 Simpson Kevin 332 Tebes Cinthya 339 Siñeriz Manuel 195 Teeling Hanno 83 Smith Woutrina 102 Teisserenc Roman 73 Soares Rosado Alexandre 319 Tello Camacho Edisson 13 Solano-Campos Frank 333 Teunisse Guus 112 Solano-González Stefany 315 Thalasso Frederic 73 Soliz Alfredo 216 Thdmi Consortium 172 Sommaruga Ruben 108 The Tara Oceans Coordinators 32 Somonte Danalay 31, 264, 265, 266 Thomas Ledger 161 Sønderholm Fredrik 77 Tischler Nicole 50 Song Se-jin 172 Toninato De Paula Gabriela 340 Soria Mariana Noelia 20, 334 Torres Ernesto 341 Sotelo José 84, 196, 300 Torres-Rojas Esperanza 93 Soto Jorge 282 Tortella Gonzalo 191 Soto Rueda Eliana 261 Tosado Eduardo 341, 342 Souza Bruno C. E. 125 Tragin Margot 200 Souza José Augusto 51, 247, 248, 254, 335 Trefault Nicole 64, 106, 267, 283, 368 Spear John 77 Triver Salomon Johanna 286 Stamps Blake 77 Trombert Annette 138 Stapanenko Tatiana 20, 334 Tsai Siu Mui 55, 182 Starevich Viviana Ayelén 336 Tufo Ana 351 Stewart Frank 211 Tupa Andrade Lisset Sara 158, 193 Stich Anna 322 Stief Peter 187 U Stucken Karina 337 Ulate-Naranjo Karol 271 Suárez María Eugenia 281 Ulloa Claudia 52, 157 Suarez Rudy 251 Ulloa María Teresa 309 Sudek Sebastian 303 Ulloa Osvaldo 68, 105, 211, 276, 307, 368 Sulbaran Yoelvis 155 Ulloa Ricardo 217 Sullivan Matthew 40 Umaña-Castro Rodolfo 271 Sun Yi-qian 322 Undabarrena Agustina 94, 371 Unrein Fernando 213, 280, 293 T Urbieta María Sofía 132, 217, 231, 232, 235 Tallarico Pupo Mónica 300, 340 Uribe Acosta Melissa 343 Tamayo-Leiva Javier 338 Uribe Sandra I 364

388 Uribe-Lorío Lorena 143 Vega-Vela Nelson E. 238 Uribe-Redlich Patricio 344 Veiga Patrick 172 Urrutia Araxi 317 Vejar Drina 355 Urrutia-Fucugauchi Jaime 317 Velásquez Alexis Andrés 257, 356 Urtubia Alejandra 268 Vélez Iván D. 119 Urzúa Ximena 297 Velozo Sebastián Ignacio 277, 357 Venegas Francisca 112 V Venegas Luis 152 Val Del Río Ángeles 146 Vera Leonardo 102 Valdés Jorge 65 Vera Mario 201 Valdes Valentina Paz 345 Vergara Alejandra 257 Valencia Pedro 204, 268 Vergara Eva 65, 272 Valencia Ricardo 94, 371 Vergara-Barros Pablo 358 Valenzuela Bernardita 316 Vergé Valerie 64 Valenzuela Cristian 141 Vicente Miguel 121 Valenzuela Daniel 347 Victoria Yanara 31 Valenzuela Millarca 198 Vidal Gonzalo Andrés 359, 367 Valenzuela Miryam 346 Vidaurre-Barahona Daniela 143 Valenzuela Ximena 206 Viera Marisa 174 Vallejo Marisol 194 Vignale Federico 20 Valpuesta Jose María 121 Vilanova-Cuevas Brayan 349, 360 Van Aerle Ronny 317 Villafañe Patricio 20 Vanderzalm J 27 Villagra Nicolas 102 Vanessa Da Costa Andrade 56 Villalba Primitz Julia 361 Varas Macarena 74 Villalobos Karla 352 Varas-Godoy Manuel 153 Villalobos-Solís Jordan 333 Vargas Cristian 105 Villarroel Daniel 116 Vargas Ignacio T. 53, 201, 128 Villasante Alejandro 305 Vargas Marta 29 Villca Grecia 133 Vargas-Reyes Matías 348 Villegas Pamela 120 Vásquez Mónica 92, 106, 121, 220, 277, 279, 357 Vinda Jorge S. 29 Vaulot Daniel 200 Vio Santiago Adolfo 362, 363 Vazquez Frances Enid 341, 349 Viollier Patrick 67 Vázquez Nallely 350 Visscher Pieter 20 Vazquez Susana 163, 351, 361 Vivero Rafael Jose 119, 364 Vázquez-Murrieta Soledad 110 Von Peter 95 Vazquez-Sanchez Frances 349 Vredenburg Vance T. 22 Veas Karla 352 Vullo Diana Lía 262, 365 Vega Evelyn Nathalie 353 Vega-Celedón Paulina 142, 354, 356 Vega-Corrales Luis 75, 315

389 W Z Wade Jeffrey 301 Zagarese Horacio 293 Wall Luis Gabriel 41, 299 Zambrano María Mercedes 148, 185 Walsh T 27 Zamora Jesús 31 Werneck Tatiana 366 Zamora Natali 370 Whitfield Steven 252 Zamora-Leiva Leonardo 371 Wick Lukas Y. 171 Zamorano Nicolás 372 Wilkens Marcela 290 Zamorano Pedro 209, 316 Wong C. M. V. L. 226 Zampieri Bruna Del Busso 122, 254, 373 Wong Idania 31, 265 Zapata L 160 Woodhams Douglas C. 22 Zapata Manuel 258, 324 Woolery Matt 120 Zehl Martin 322 Worden Alexandra Z. 303 Zhang Qian 71 Wulff Cristian 324 Zhang X. 218 Wylie J 27 Ziliani Agustina 351 Zilli Jerri Édson 76 Y Zinola Guillermo 170 Yanez Guillermo 367 Zotchev Sergey 42, 322 Yánez Montalvo Alfredo Francisco 111, 369 Zuber Benoit 67 Yanez Sonia 368 Zunino Pablo 124, 184 Yáñez Carolina 370 Zuñiga Ibrahim 252 Yu Chang-ping 273

390