DOCSLIB.ORG

Probing the Evolution, Ecology and Physiology of Marine Protists Using Transcriptomics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Probing the Evolution, Ecology and Physiology of Marine Protists Using Transcriptomics REVIEWS Probing the evolution, ecology and physiology of marine protists using transcriptomics David A. Caron1, Harriet Alexander2, Andrew E. Allen3,4, John M. Archibald5,6, E. Virginia Armbrust7, Charles Bachy8, Callum J. Bell9, Arvind Bharti10, Sonya T. Dyhrman11, Stephanie M. Guida9, Karla B. Heidelberg1, Jonathan Z. Kaye12, Julia Metzner12, Sarah R. Smith4 and Alexandra Z. Worden6,8 Abstract | Protists, which are single-celled eukaryotes, critically influence the ecology and chemistry of marine ecosystems, but genome-based studies of these organisms have lagged behind those of other microorganisms. However, recent transcriptomic studies of cultured species, complemented by meta-omics analyses of natural communities, have increased the amount of genetic information available for poorly represented branches on the tree of eukaryotic life. This information is providing insights into the adaptations and interactions between protists and other microorganisms and macroorganisms, but many of the genes sequenced show no similarity to sequences currently available in public databases. A better understanding of these newly discovered genes will lead to a deeper appreciation of the functional diversity and metabolic processes in the ocean. In this Review, we summarize recent developments in our understanding of the ecology, physiology and evolution of protists, derived from transcriptomic studies of cultured strains and natural communities, and discuss how these novel large-scale genetic datasets will be used in the future. Phototrophy Marine protists are a phylogenetically broad group of chloroplasts but also consume prey. Protists typically A nutritional mode that eukaryotic organisms that are capable of existence as reproduce through mitotic division rather than through involves the use of light for the single cells, although many form colonies that exhibit sexual reproduction, which enables populations to double production of organic carbon coordinated behaviour. The term protist is largely histor- in a few hours to a few days. Their rapid growth rates ena- and the acquisition of energy. ical in nature, at one time referring to a kingdom-level ble them to contribute to important ecosystem functions: 1 Phytoplankton distinction in Whittaker’s tree of life , but still commonly protists have roles in primary production, as partners in Planktonic protists that use applied to all eukaryotes that are not plants, multi cellular various symbiotic relation ships and, at multiple trophic phototrophy as their nutritional animals or fungi. Most protists are microscopic, but levels, as links between the small animals that prey on mode. The term has ecological collectively these species span more than five orders of them and the vast numbers of bacteria, archaea, protists importance but little (FIG. 1) phylogenetic importance magnitude in size, display a myriad of morphologies, and even some metazoa that they consume . These because the behaviour occurs behaviours and nutritional modes, and have pivotal eco- links in the food web are essential for the biogeochemi- across many lineages of logical roles in marine ecosystems2,3. Protistan species cal cycles of the ocean, including the transport of carbon protists. are the most abundant eukaryotes in marine pelagic to the deep ocean. communities and constitute a substantial portion of the Despite the fundamental roles of protists in marine total biomass in the plankton. ecosystems, genome-based studies of these species Correspondence to D.A.C. Nutritional modes of protists range from pure have lagged behind those of other marine organ- Department of Biological photo trophy among many phytoplankton to the pure isms. However, in the past few decades, a lot of DNA Sciences, University of hetero trophy of species traditionally called protozoa. sequence information has become available for proti- Southern California, Protozoa generally derive their nutrition from the inges- stan marker genes4, transcriptomes5, genomes (almost 3616 Trousdale Parkway, 6 metatranscriptomes5 Los Angeles, California tion of bacteria, archaea or other eukaryotes, but some 20 complete genomes in total) , and 7 90089, USA. are parasites (or more accurately, parasitoids) of other even metagenomes . Analyses of these data have altered [email protected] protists and metazoa. In addition, many protists com- our understanding of protistan diversity, phylogeny, doi:10.1038/nrmicro.2016.160 bine photo trophy and heterotrophy in a single species evolution and physiology, and enriched our knowledge Published online 21 Nov 2016 (mixotrophy), such as phytoflagellates that have of various ecological interactions. NATURE REVIEWS | MICROBIOLOGY ADVANCE ONLINE PUBLICATION | 1 ©2016 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved. REVIEWS Author addresses A few large culture-based and field-based projects have begun to address this disparity. The Marine 1 Department of Biological Sciences, University of Southern California, 3616 Trousdale Parkway, Microbial Eukaryote Transcriptome Sequencing Los Angeles, California 90089, USA. 2Department of Population Health and Reproduction, School of Veterinary Medicine, Project (MMETSP) released nearly 680 transcriptome 1 Shields Avenue, University of California Davis, Davis, California 95616, USA. assemblies of pure cultures of protists in 2014, repre- 3Microbial and Environmental Genomics, J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, senting isolates from much of the world’s oceans and a San Diego, California 92037, USA. few freshwater ecosystems (BOX 1). The MMETSP was 4Scripps Institution of Oceanography, Integrative Oceanography Division, University of California San Diego, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA. conceived to facilitate comparative transcriptomics of 5Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper environmentally important microbial eukaryotes. The Medical Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2, Canada. dataset increased ~50-fold the amount of information 6Canadian Institute for Advanced Research, 180 Dundas Street W, Toronto, Ontario M5G 1Z8, available on gene expression from free-living protists, Canada. and doubled the number of protistan lineages for which 7School of Oceanography, University of Washington, 1503 NE Boat Street, Seattle, 5 Washington 98195, USA. genomic studies have been conducted . Subsequent 17 8Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, work has continued to improve the gene assemblies . California 95039, USA. Concomitantly, two field programmes (the Tara Oceans 9National Center for Genome Resources, 2935 Rodeo Park Drive East, Santa Fe, and Malaspina expeditions)4,18 have circumnavigated the New Mexico 87505, USA. 10Syngenta Biotechnology, 629 Davis Drive, Research Triangle Park, North Carolina 27709, USA. planet collecting samples to provide an enormous sam- 11Department of Earth and Environmental Sciences and the Lamont-Doherty Earth Observatory, ple set for the investigation of the abundances, morph- Columbia University, 61 Route 9W, Palisades, New York 10964, USA. ologies, genetic diversity and ecological significance of 12Gordon and Betty Moore Foundation, 1661 Page Mill Road, Palo Alto, California 94304, USA. marine protists. These studies highlight the importance of marine protists, demonstrate the genetic and physio- The historical partitioning of eukaryotes into king- logical potentials that underpin their activities and doms based on morphological characteristics, multi- provide new insights into the evolution of these species. cellularity or trophic mode1 has been challenged and Heterotrophy changed in recent years by information on genetic Insights into protistan phylogeny and evolution A nutritional mode that relatedness. The resulting framework for a molecular Modern protistan phylogeny. Our view of the evolution- involves the use of preformed organic matter for the taxonomy for protists has raised questions regarding ary relationships among protistan lineages has changed acquisition of carbon and the biogeography of these taxa and the adequacy of the substantially during the past few decades (FIG. 2). The energy. classical morphological species concept for protists8–10. Whittaker system1, which prevailed for two decades, Direct sequencing of rRNA genes from environmental grouped organisms into five kingdoms: Monera, Protista, Protozoa samples has revealed a huge protistan diversity, includ- Plantae, Fungi and Animalia. Eukaryotes that can exist as Protists that are not 11,12 photosynthetic, but are instead ing new lineages , and has stimulated hypotheses single cells were contained within the kingdom Protista. dependent on the ingestion of regarding the protistan rare biosphere — diverse taxa Protists were further organized according to morphology preformed organic matter present at low relative abundances in virtually all nat- and nutritional preferences, a scheme that was practical (usually prey) for their ural ecosystems — which may play important parts in for biologists of the time but artificially separated some nutrition. This older term is still in use; ‘heterotrophic protists’ the evolution of eukaryotes as well as in the stability closely related taxa that have different nutritional behav- 13–15 is used synonymously. and functional resilience of microbial communities . iours (for example, photosynthetic and heterotrophic Importantly, studies of protistan gene expression
Load more

Recommended publications
  • Molecular Data and the Evolutionary History of Dinoflagellates by Juan Fernando Saldarriaga Echavarria Diplom, Ruprecht-Karls-Un
    Molecular data and the evolutionary history of dinoflagellates by Juan Fernando Saldarriaga Echavarria Diplom, Ruprecht-Karls-Universitat Heidelberg, 1993 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES Department of Botany We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA November 2003 © Juan Fernando Saldarriaga Echavarria, 2003 ABSTRACT New sequences of ribosomal and protein genes were combined with available morphological and paleontological data to produce a phylogenetic framework for dinoflagellates. The evolutionary history of some of the major morphological features of the group was then investigated in the light of that framework. Phylogenetic trees of dinoflagellates based on the small subunit ribosomal RNA gene (SSU) are generally poorly resolved but include many well- supported clades, and while combined analyses of SSU and LSU (large subunit ribosomal RNA) improve the support for several nodes, they are still generally unsatisfactory. Protein-gene based trees lack the degree of species representation necessary for meaningful in-group phylogenetic analyses, but do provide important insights to the phylogenetic position of dinoflagellates as a whole and on the identity of their close relatives. Molecular data agree with paleontology in suggesting an early evolutionary radiation of the group, but whereas paleontological data include only taxa with fossilizable cysts, the new data examined here establish that this radiation event included all dinokaryotic lineages, including athecate forms. Plastids were lost and replaced many times in dinoflagellates, a situation entirely unique for this group. Histones could well have been lost earlier in the lineage than previously assumed.
    [Show full text]
  • Molecular Underpinnings and Biogeochemical Consequences of Enhanced 8 Diatom Growth in a Warming Southern Ocean
    bioRxiv preprint doi: https://doi.org/10.1101/2020.07.01.177865; this version posted July 2, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 2 3 4 Main Manuscript for: 5 6 7 Molecular underpinnings and biogeochemical consequences of enhanced 8 diatom growth in a warming Southern Ocean 9 10 11 Loay Jabrea, Andrew E. Allenb,c*, J. Scott P. McCaina, John P. McCrowb, Nancy Tenenbaumd, 12 Jenna L. Spackeene, Rachel E. Siplere,f, Beverley R. Greeng, Deborah A. Bronke,h, David A. 13 Hutchinsd*, Erin M. Bertranda,*# 14 a Dept. of Biology, Dalhousie University, 1355 Oxford Street, PO BOX 15000, Life Sciences 15 Center, Halifax, NS, Canada, B3H 4R2 16 b Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, CA 92037, USA 17 c Integrative Oceanography Division, Scripps Institution of Oceanography, University of 18 California, San Diego, La Jolla, CA 92037, USA 19 d University of Southern California, 3616 Trousdale Parkway, Los Angeles, CA 90089, USA 20 e Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA, 23062, 21 USA 22 f Memorial University of Newfoundland, 0 Marine Drive, Ocean Sciences Centre, St. John’s, NL, 23 Canada, A1A 4A8 24 g Dept. of Botany, University of British Columbia, #3200-6270 University Boulevard, Vancouver, 25 BC, Canada, V6T 1Z4 26 h Bigelow Laboratory for Ocean Sciences, 60 Bigelow Drive, East Boothbay, ME 04544, USA 27 *Corresponding Authors.
    [Show full text]
  • Akashiwo Sanguinea
    Ocean ORIGINAL ARTICLE and Coastal http://doi.org/10.1590/2675-2824069.20-004hmdja Research ISSN 2675-2824 Phytoplankton community in a tropical estuarine gradient after an exceptional harmful bloom of Akashiwo sanguinea (Dinophyceae) in the Todos os Santos Bay Helen Michelle de Jesus Affe1,2,* , Lorena Pedreira Conceição3,4 , Diogo Souza Bezerra Rocha5 , Luis Antônio de Oliveira Proença6 , José Marcos de Castro Nunes3,4 1 Universidade do Estado do Rio de Janeiro - Faculdade de Oceanografia (Bloco E - 900, Pavilhão João Lyra Filho, 4º andar, sala 4018, R. São Francisco Xavier, 524 - Maracanã - 20550-000 - Rio de Janeiro - RJ - Brazil) 2 Instituto Nacional de Pesquisas Espaciais/INPE - Rede Clima - Sub-rede Oceanos (Av. dos Astronautas, 1758. Jd. da Granja -12227-010 - São José dos Campos - SP - Brazil) 3 Universidade Estadual de Feira de Santana - Departamento de Ciências Biológicas - Programa de Pós-graduação em Botânica (Av. Transnordestina s/n - Novo Horizonte - 44036-900 - Feira de Santana - BA - Brazil) 4 Universidade Federal da Bahia - Instituto de Biologia - Laboratório de Algas Marinhas (Rua Barão de Jeremoabo, 668 - Campus de Ondina 40170-115 - Salvador - BA - Brazil) 5 Instituto Internacional para Sustentabilidade - (Estr. Dona Castorina, 124 - Jardim Botânico - 22460-320 - Rio de Janeiro - RJ - Brazil) 6 Instituto Federal de Santa Catarina (Av. Ver. Abrahão João Francisco, 3899 - Ressacada, Itajaí - 88307-303 - SC - Brazil) * Corresponding author: [email protected] ABSTRAct The objective of this study was to evaluate variations in the composition and abundance of the phytoplankton community after an exceptional harmful bloom of Akashiwo sanguinea that occurred in Todos os Santos Bay (BTS) in early March, 2007.
    [Show full text]
  • Growth and Grazing Rates of the Herbivorous Dinoflagellate Gymnodinium Sp
    MARINE ECOLOGY PROGRESS SERIES Published December 16 Mar. Ecol. Prog. Ser. Growth and grazing rates of the herbivorous dinoflagellate Gymnodinium sp. from the open subarctic Pacific Ocean Suzanne L. Strom' School of Oceanography WB-10, University of Washington. Seattle. Washington 98195, USA ABSTRACT: Growth, grazing and cell volume of the small heterotroph~cdinoflagellate Gyrnnodin~um sp. Isolated from the open subarctic Pacific Ocean were measured as a funct~onof food concentration using 2 phytoplankton food species. Growth and lngestlon rates increased asymptotically with Increas- ing phytoplankon food levels, as did grazer cell volume; rates at representative oceanic food levels were high but below maxima. Clearance rates decreased with lncreaslng food levels when Isochrysis galbana was the food source; they increased ~vithlncreaslng food levels when Synechococcus sp. was the food source. There was apparently a grazlng threshold for Ingestion of Synechococcus: below an initial Synechococcus concentration of 20 pgC 1.' ingestion rates on this alga were very low, while above this initial concentratlon Synechococcus was grazed preferent~ally Gross growth efficiency varied between 0.03 and 0.53 (mean 0.21) and was highest at low food concentrations. Results support the hypothesis that heterotrophic d~noflagellatesmay contribute to controlling population increases of small, rap~dly-grow~ngphytoplankton specles even at low oceanic phytoplankton concentrations. INTRODUCTION as Gymnodinium and Gyrodinium is difficult or impos- sible using older preservation and microscopy tech- Heterotrophic dinoflagellates can be a significant niques; experimental emphasis has been on more component of the microzooplankton in marine waters. easily recognizable and collectable microzooplankton In the oceanic realm, Lessard (1984) and Shapiro et al.
    [Show full text]
  • The Planktonic Protist Interactome: Where Do We Stand After a Century of Research?
    bioRxiv preprint doi: https://doi.org/10.1101/587352; this version posted May 2, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Bjorbækmo et al., 23.03.2019 – preprint copy - BioRxiv The planktonic protist interactome: where do we stand after a century of research? Marit F. Markussen Bjorbækmo1*, Andreas Evenstad1* and Line Lieblein Røsæg1*, Anders K. Krabberød1**, and Ramiro Logares2,1** 1 University of Oslo, Department of Biosciences, Section for Genetics and Evolutionary Biology (Evogene), Blindernv. 31, N- 0316 Oslo, Norway 2 Institut de Ciències del Mar (CSIC), Passeig Marítim de la Barceloneta, 37-49, ES-08003, Barcelona, Catalonia, Spain * The three authors contributed equally ** Corresponding authors: Ramiro Logares: Institute of Marine Sciences (ICM-CSIC), Passeig Marítim de la Barceloneta 37-49, 08003, Barcelona, Catalonia, Spain. Phone: 34-93-2309500; Fax: 34-93-2309555. [email protected] Anders K. Krabberød: University of Oslo, Department of Biosciences, Section for Genetics and Evolutionary Biology (Evogene), Blindernv. 31, N-0316 Oslo, Norway. Phone +47 22845986, Fax: +47 22854726. [email protected] Abstract Microbial interactions are crucial for Earth ecosystem function, yet our knowledge about them is limited and has so far mainly existed as scattered records. Here, we have surveyed the literature involving planktonic protist interactions and gathered the information in a manually curated Protist Interaction DAtabase (PIDA). In total, we have registered ~2,500 ecological interactions from ~500 publications, spanning the last 150 years.
    [Show full text]
  • Check List 15 (5): 951–963
    15 5 ANNOTATED LIST OF SPECIES Check List 15 (5): 951–963 https://doi.org/10.15560/15.5.951 Dinoflagellates in tropical estuarine waters from the Maraú River, Camamu Bay, northeastern Brazil Caio Ceza da Silva Nunes1, Sylvia Maria Moreira Susini-Ribeiro1, 2, Kaoli Pereira Cavalcante3 1 Mestrado em Sistemas Aquáticos Tropicais, Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, Salobrinho, 45662090 Ilhéus, BA, Brazil. 2 Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, Salobrinho, 45662090 Ilhéus, BA, Brazil. 3 Universidade Estadual Vale do Acaraú, Avenida da Universidade, 850, Campus da Betânia, Betânia, 62040370, Sobral, CE, Brazil. Corresponding author: Caio Ceza da Silva Nunes, [email protected] Abstract Dinoflagellates display great diversity in tropical regions and play an important role in the complex microbial food webs of marine and brackish environments. The goal of this study is to identify planktonic dinoflagellates and their distribution in the estuary of the Maraú River, Camamu Bay, state of Bahia, in a region with increasing use of shellfish farming. Samples were carried out monthly from August 2006 to July 2007 at four stations along the estuary. Plankton was sampled with a 20 μm mesh net. We identified 20 dinoflagellate species. The greatest species richness was ob- served in the genera Protoperidinium (five spp.), Tripos (four spp.), and Prorocentrum (three spp.). Based on literature, six species were classified as potentially harmful: Akashiwo sanguinea, Dinophysis caudata, Gonyaulax spinifera, Prorocentrum micans, Scrippsiella cf. acuminata, and Tripos furca. Protoperidinium venustum was recorded for the first time in coastal waters of Bahia. Keywords Brackish water, Dinophyta, distribution, potentially harmful species, taxonomy.
    [Show full text]
  • A Morphological Re-Description of Ploeotia Pseudanisonema, and Phylogenetic Analysis of the Genus Ploeotia
    A Morphological Re-Description of Ploeotia pseudanisonema, and Phylogenetic Analysis of the Genus Ploeotia by Andrew Buren Brooks (Under the direction of Mark A. Farmer) Abstract The genus Ploeotia represents a group of small, colorless, heterotrophic euglenids commonly found in shallow-water marine sediments. Species belonging to this genus have histori- cally been poorly described and studied. However, a Group I intron discovered within the small subunit ribosomal DNA gene of Ploeotia costata, makes P. costata the only euglena- zoan known to possess an actively splicing Group I intron. This intron contains conserved secondary structures that indicate monophyly with introns found in Stramenopiles and Ban- giales red algae. This project describes the internal and external morphology of a related species, Ploeotia pseudanisonema, using light and electron microscopy, and investigates the possibility of a Group I intron within P. pseudanisonema. Using recently obtained SSU rRNA sequences, we also examine the phylogeny of Ploeotia, and comment on the relationship of the genus Keelungia to Ploeotia. Index words: Ploeotia pseudanisonema, Ploeotia costata, Ploeotia vitrea, Keelungia pulex, Transmission electron microscopy, Scanning electron microscopy, Small subunit rRNA, Euglenozoan Phylogeny A Morphological Re-Description of Ploeotia pseudanisonema, and Phylogenetic Analysis of the Genus Ploeotia by Andrew Buren Brooks B.S., University of Alabama, 2009 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree Master of Science Athens, Georgia 2010 c 2014 Andrew Buren Brooks All Right Reserved A Morphological Re-Description of Ploeotia pseudanisonema, and Phylogenetic Analysis of the Genus Ploeotia by Andrew Buren Brooks Approved: Major Professor: Mark A.
    [Show full text]
  • Analysis of Transposable Elements and Protein Divergence Across Diatoms
    Analysis of Transposable Elements and Protein Divergence across Diatoms Nina Denne, Illinois Mathematics and Science Academy Matthew Parks, Norm Wickett, & Matthew Johnson, Chicago Botanic Garden IMSAloquium – 4/26/2017 IMSAloquium 2017 1 Outline • Topic 1: Introduction to Diatoms • Topic 2: Introduction to Transposable Elements • Topic 3: Introduction to Protein Divergence • Topic 4: Methods • Topic 5: Transposable Element Results • Topic 6: Protein Divergence Results • Topic 7: Discussion IMSAloquium 2017 2 Diatoms • Responsible for up to 20% of total global photosynthesis • 3 diatom genomes have been sequenced: Thalassiosira pseudonana, Phaeodactylum tricornutum, Fragiliariopsis cylindrus (closest relative: Nannochloropsis gaditana) • How do these diatom genomes compare to Psammoneis japonica in terms of transposable elements and protein divergence? Topic: Introduction to Diatoms - IMSAloquium 2017 3 Diatoms Us! Topic: Introduction to Diatoms IMSAloquium 2017 4 Nannochloropsis gaditana Thalassiosira pseudonana Psammoneis japonica Phaeodactylum tricornutum Fragilariopsis cylindrus Topic: Introduction to Diatoms - IMSAloquium 2017 5 Transposable Elements • DNA sequences that can excise themselves and reinsert themselves in the genome • Regulate gene expression • Two main classes: • 1. Class 1 transposons (retrotransposons) • 2. Class 2 transposons (DNA transposons) • Diatom-specific lineages: CoDiI and CoDiII • Important in understanding genome function and evolution Topic: Transposable Element Introduction - IMSAloquium 2017 6 Protein
    [Show full text]
  • Biology and Systematics of Heterokont and Haptophyte Algae1
    American Journal of Botany 91(10): 1508±1522. 2004. BIOLOGY AND SYSTEMATICS OF HETEROKONT AND HAPTOPHYTE ALGAE1 ROBERT A. ANDERSEN Bigelow Laboratory for Ocean Sciences, P.O. Box 475, West Boothbay Harbor, Maine 04575 USA In this paper, I review what is currently known of phylogenetic relationships of heterokont and haptophyte algae. Heterokont algae are a monophyletic group that is classi®ed into 17 classes and represents a diverse group of marine, freshwater, and terrestrial algae. Classes are distinguished by morphology, chloroplast pigments, ultrastructural features, and gene sequence data. Electron microscopy and molecular biology have contributed signi®cantly to our understanding of their evolutionary relationships, but even today class relationships are poorly understood. Haptophyte algae are a second monophyletic group that consists of two classes of predominately marine phytoplankton. The closest relatives of the haptophytes are currently unknown, but recent evidence indicates they may be part of a large assemblage (chromalveolates) that includes heterokont algae and other stramenopiles, alveolates, and cryptophytes. Heter- okont and haptophyte algae are important primary producers in aquatic habitats, and they are probably the primary carbon source for petroleum products (crude oil, natural gas). Key words: chromalveolate; chromist; chromophyte; ¯agella; phylogeny; stramenopile; tree of life. Heterokont algae are a monophyletic group that includes all (Phaeophyceae) by Linnaeus (1753), and shortly thereafter, photosynthetic organisms with tripartite tubular hairs on the microscopic chrysophytes (currently 5 Oikomonas, Anthophy- mature ¯agellum (discussed later; also see Wetherbee et al., sa) were described by MuÈller (1773, 1786). The history of 1988, for de®nitions of mature and immature ¯agella), as well heterokont algae was recently discussed in detail (Andersen, as some nonphotosynthetic relatives and some that have sec- 2004), and four distinct periods were identi®ed.
    [Show full text]
  • Massisteria Marina Larsen & Patterson 1990
    l MARINE ECOLOGY PROGRESS SERIES Vol. 62: 11-19, 1990 1 Published April 5 l Mar. Ecol. Prog. Ser. l Massisteria marina Larsen & Patterson 1990, a widespread and abundant bacterivorous protist associated with marine detritus David J. patterson', Tom ~enchel~ ' Department of Zoology. University of Bristol. Bristol BS8 IUG. United Kingdom Marine Biological Laboratory, Strandpromenaden, DK-3000 Helsinger, Denmark ABSTRACT: An account is given of Massisteria marina Larsen & Patterson 1990, a small phagotrophic protist associated with sediment particles and with suspended detrital material in littoral and oceanic marine waters. It has been found at sites around the world. The organism has an irregular star-shaped body from which radiate thin pseudopodia with extrusomes. There are 2 inactive flagella. The organism is normally sedentary but, under adverse conditions, the arms are resorbed, the flagella become active, and the organism becomes a motile non-feeding flagellate. The ecological niche occupied by this organism and its phylogenetic affinities are discussed. INTRODUCTION (Patterson & Fenchel 1985, Fenchel & Patterson 1986, 1988, V~rs1988, Larsen & Patterson 1990). Here we Much of the carbon fixed in marine ecosystems is report on a protist, Massisteria marina ', that is specifi- degraded by microbial communities and it is held that cally associated with planktonic and benthic detritus protists, especially flagellates under 10 pm in size, and appears to be widespread and common. exercise one of the principal controlling influences over bacterial growth rates and numbers (Fenchel 1982, Azam et al. 1983, Ducklow 1983, Proctor & Fuhrman MATERIALS AND METHODS 1990). Detrital aggregates, whether benthic or in the water column, may support diverse and active microbial Cultures were established by dilution series from communities that include flagellates (Wiebe & Pomeroy water samples taken in the Limfjord (Denmark), and 1972, Caron et al.
    [Show full text]
  • Medical Parasitology
    MEDICAL PARASITOLOGY Anna B. Semerjyan Marina G. Susanyan Yerevan State Medical University Yerevan 2020 1 Chapter 15 Medical Parasitology. General understandings Parasitology is the study of parasites, their hosts, and the relationship between them. Medical Parasitology focuses on parasites which cause diseases in humans. Awareness and understanding about medically important parasites is necessary for proper diagnosis, prevention and treatment of parasitic diseases. The most important element in diagnosing a parasitic infection is the knowledge of the biology, or life cycle, of the parasites. Medical parasitology traditionally has included the study of three major groups of animals: 1. Parasitic protozoa (protists). 2. Parasitic worms (helminthes). 3. Arthropods that directly cause disease or act as transmitters of various pathogens. Parasitism is a form of association between organisms of different species known as symbiosis. Symbiosis means literally “living together”. Symbiosis can be between any plant, animal, or protist that is intimately associated with another organism of a different species. The most common types of symbiosis are commensalism, mutualism and parasitism. 1. Commensalism involves one-way benefit, but no harm is exerted in either direction. For example, mouth amoeba Entamoeba gingivalis, uses human for habitat (mouth cavity) and for food source without harming the host organism. 2. Mutualism is a highly interdependent association, in which both partners benefit from the relationship: two-way (mutual) benefit and no harm. Each member depends upon the other. For example, in humans’ large intestine the bacterium Escherichia coli produces the complex of vitamin B and suppresses pathogenic fungi, bacteria, while sheltering and getting nutrients in the intestine. 3.
    [Show full text]
  • Mixotrophic Protists Among Marine Ciliates and Dinoflagellates: Distribution, Physiology and Ecology
    FACULTY OF SCIENCE UNIVERSITY OF COPENHAGEN PhD thesis Woraporn Tarangkoon Mixotrophic Protists among Marine Ciliates and Dinoflagellates: Distribution, Physiology and Ecology Academic advisor: Associate Professor Per Juel Hansen Submitted: 29/04/10 Contents List of publications 3 Preface 4 Summary 6 Sammenfating (Danish summary) 8 สรุป (Thai summary) 10 The sections and objectives of the thesis 12 Introduction 14 1) Mixotrophy among marine planktonic protists 14 1.1) The role of light, food concentration and nutrients for 17 the growth of marine mixotrophic planktonic protists 1.2) Importance of marine mixotrophic protists in the 20 planktonic food web 2) Marine symbiont-bearing dinoflagellates 24 2.1) Occurrence of symbionts in the order Dinophysiales 24 2.2) The spatial distribution of symbiont-bearing dinoflagellates in 27 marine waters 2.3) The role of symbionts and phagotrophy in dinoflagellates with symbionts 28 3) Symbiosis and mixotrophy in the marine ciliate genus Mesodinium 30 3.1) Occurrence of symbiosis in Mesodinium spp. 30 3.2) The distribution of marine Mesodinium spp. 30 3.3) The role of symbionts and phagotrophy in marine Mesodinium rubrum 33 and Mesodinium pulex Conclusion and future perspectives 36 References 38 Paper I Paper II Paper III Appendix-Paper IV Appendix-I Lists of publications The thesis consists of the following papers, referred to in the synthesis by their roman numerals. Co-author statements are attached to the thesis (Appendix-I). Paper I Tarangkoon W, Hansen G Hansen PJ (2010) Spatial distribution of symbiont-bearing dinoflagellates in the Indian Ocean in relation to oceanographic regimes. Aquat Microb Ecol 58:197-213.
    [Show full text]