DOCSLIB.ORG

Harmful Cyanobacteria Blooms and Their Toxins In

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Harmful Cyanobacteria Blooms and Their Toxins In Harmful cyanobacteria blooms and their toxins in Clear Lake and the Sacramento-San Joaquin Delta (California) 10-058-150 Surface Water Ambient Monitoring Program (SWAMP) Prepared for: Central Valley Regional Water Quality Control Board 11020 Sun Center Drive, Suite 200 Rancho Cordova, CA 95670 Prepared by: Cécile Mioni (Project Director) & Raphael Kudela (Project co-Director) University of California, Santa Cruz - Institute of Marine Sciences Dolores Baxa (Project co-Director) University of California, Davis – School of Veterinary Medicine Contract manager: Meghan Sullivan Central Valley Regional Water Quality Control Board _________________ With technical contributions by: Kendra Hayashi (Project manager), UCSC Thomas Smythe (Field Officer) and Chris White, Lake County Water Resources Scott Waller (Field Officer) and Brianne Sakata, EMP/DWR Tomo Kurobe (Molecular Biologist), UCD David Crane (Toxicology), DFG-WPCL Kim Ward, SWRCB/DWQ Lenny Grimaldo (Assistance for Statistic Analyses), Bureau of Reclamation Peter Raimondi (Assistance for Statistic Analyses), UCSC Karen Tait, Lake County Health Office Abstract Harmful cyanobacteria and their toxins are growing contaminants of concern. Noxious toxins produced by HC, collectively referred as cyanotoxins, reduce the water quality and may impact the supply of clean water for drinking as well as the water quality which directly impacts the livelihood of other species including several endangered species. USEPA recently (May 29, 2008) made the decision to add microcystin toxins as an additional cause of impairment for the Klamath River, CA. However, harmful cyanobacteria are some of the less studied causes of impairment in California water bodies and their distribution, abundance and dynamics, as well as the conditions promoting their proliferation and toxin production are not well characterized. The goal of the work presented here was to monitor the distribution of Microcystis aeruginosa as well as other harmful cyanobacteria of concern and their associated toxins in the surface waters of two California water bodies listed in the 303(d) and that have been impacted by recurrent harmful cyanobacterial blooms (cyanoHABs): the Sacramento-San Joaquin Delta and Clear Lake. We used a multidisciplinary approach combining traditional microscopy and toxicology analyses with molecular analyses. Using this approach, we successfully identified key cyanobacteria species that could not be identified using traditional microscopy-based techniques alone. This combined approach allowed us to accurately determine the cyanoHABs composition and toxicity as well as to gather critical information from the literature to interpret the correlations between individual cyanoHABs taxa and their environmental controls. Results from this study indicate that several environmental drivers rather than one single stressor act in conjunction to control cyanoHABs and toxicity in Clear Lake and the Delta. Surface water temperature, nitrogen and phosphorus concentrations appear to be key drivers of cyanoHABs composition and toxicity but additional environmental stressors specific to each system and to each individual taxa may also play a significant role. Based on our findings, suggestions for the implementation of future research programs as well as future management plans are also provided in this report. i List of abbreviations and acronyms Abbreviation Definition Comments ALG-sp. Algoriphagus sp. Either Algoriphagus yeomjeoni or A. ratkowskyi ANA-LM Anabaena lemmermannii Taxonomic synonym of Dolichospermum lemmermannii ANA-sp Anabaena spp. APHA-FL Aphanizomenon flos-aquae aPR Alpha proteobacterium Sequences of alpha proteobacterium in the data base are limited precluding identification at species level BCL-PM Bacillus pumilus CyanoHABS Harmful Cyanobacterial Blooms DIN Dissolved inorganic nitrogen DO Dissolved oxygen DOC Dissolved Organic Carbon DWR Department of Water Resources EC Electrical conductivity EMP Environmental Monitoring Program FLV-TF Fluviicola taffensis IEP Interagency Ecological Program LYNG-HIE Lyngbya hieronymusii f. robusta Planktothrix cryptovaginata has identical sequences in GenBank database but microscopic observations validated L. hieronymusii as the taxonomic ID LYNG-sp Lyngbya spp. MSAE Microcystis aeruginosa NH4 Ammonium NO3 Nitrate NTU Nephelometric Turbidity Unit PNB-AL Paenibacillus alvei PNB-sp. Paenibacillus sp. PO4 Phosphate POD Pelagic Organism Decline QA Quality Assurance QAPP Quality Assurance Project Plan QC Quality Control RHD-SPH Rhodobacter sphaeroides RHD-sp. Rhodobacter sp. SOP Standard Operating Procedures SYN Synechococcus sp. WHO World Health Organization ii TABLE OF CONTENTS Page: Introduction ................................................................................................................................................................. 1 Report purpose ................................................................................................................................................ 1 Study Goal and Objectives .............................................................................................................................. 1 Background ..................................................................................................................................................... 2 Description of Study Areas ........................................................................................................................................ 5 Sacramento-San Joaquin Delta ....................................................................................................................... 5 Clear Lake ....................................................................................................................................................... 6 Materials and Methods ............................................................................................................................................... 9 Data Quality Assurance and Quality Controls ................................................................................................ 9 Summary of QC samples ................................................................................................................................. 9 Sampling and Field Water Quality Measurements ........................................................................................ 10 Sample Preparation and Processing ............................................................................................................. 11 Microscopy preparation and analysis ........................................................................................................... 12 Molecular analysis for species identification ................................................................................................ 12 Analytical chemistry procedures ................................................................................................................... 14 Toxicology analyses ...................................................................................................................................... 15 Statistics ........................................................................................................................................................ 17 Predictive modeling ....................................................................................................................................... 18 Results and discussion ............................................................................................................................................... 19 1. Sacramento-San Joaquin Delta ................................................................................................................................ 19 Physico-chemical conditions ......................................................................................................................... 19 Biological conditions ..................................................................................................................................... 20 Molecular analyses ....................................................................................................................................... 21 Toxicology analyses ...................................................................................................................................... 21 Correlations .................................................................................................................................................. 22 Modeling ....................................................................................................................................................... 22 2. Clear Lake ............................................................................................................................................................... 23 Physico-chemical conditions ......................................................................................................................... 23 Biological conditions ..................................................................................................................................... 25 Molecular analyses ....................................................................................................................................... 26 Toxicology analyses .....................................................................................................................................
Load more

Recommended publications
  • Azolla-Anabaena Symbiosis-From Traditional Agriculture to Biotechnology
    Indian Journal of Biotechnology Vol 2, January 2003, pp 26-37 Azolla-Anabaena Symbiosis-From Traditional Agriculture to Biotechnology Anjuli Pabby, Radha Prasanna and P K Singh* National Centre for Conservation and Utilization of Blue-Green Algae, Indian Agricultural Research Institute, New Delhi 110 012, India The Azolla - Anabaena symbiosis has attracted attention as a biofertilizer worldwide, especially in South East Asia. But its utilization and genetic improvement has been limited mainly due to problems associated with the isolation and characterization of cyanobionts and the relative sensitivity of the fern to extremes of temperature and light intensity. This paper reviews the historical background of Azolla, its metabolic capabilities and present day utilization in agriculture. An outline of biotechnological interventions, carried out in India and abroad, is also discussed for a better understanding of the symbiotic interactions, which can go a long way in further exploitation of this association in agriculture and environmental management. Keywords: Azolla, Anabaena, biofertilizer, fingerprinting, symbiont Introduction food and medicine, besides its role in environmental Azolla is a small aquatic fern of demonstrated management and as controlling agent for weeds and agronomic significance in both developed and mosquitoes. It also improves water quality by removal developing countries (Singh, 1979a; Lumpkin & of excess quantities of nitrate and phosphorus and is Plucknett, 1980; Watanabe, 1982; Giller, 2002). The also used as fodder, feed for fish, ducks and rabbits association between Azolla and Anabaena azollae is a (Wagner, 1997). Besides its extensive use as a N- symbiotic one, wherein the eukaryotic partner Azolla supplement in rice-based ecosystems, it has also been houses the prokaryotic endosymbiont in its leaf used in other crops such as taro, wheat, tomato and cavities and provides carbon sources and in turn banana (Van Hove, 1989; Marwaha et al.
    [Show full text]
  • Microcystis Sp. Co-Producing Microcystin and Saxitoxin from Songkhla Lake Basin, Thailand
    toxins Article Microcystis Sp. Co-Producing Microcystin and Saxitoxin from Songkhla Lake Basin, Thailand Ampapan Naknaen 1, Waraporn Ratsameepakai 2, Oramas Suttinun 1,3, Yaowapa Sukpondma 4, Eakalak Khan 5 and Rattanaruji Pomwised 6,* 1 Environmental Assessment and Technology for Hazardous Waste Management Research Center, Faculty of Environmental Management, Prince of Songkla University, Hat Yai 90110, Thailand; [email protected] (A.N.); [email protected] (O.S.) 2 Office of Scientific Instrument and Testing, Prince of Songkla University, Hat Yai 90110, Thailand; [email protected] 3 Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10330, Thailand 4 Division of Physical Science, Faculty of Science, Prince of Songkla University, Hat Yai 90110, Thailand; [email protected] 5 Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, NV 89154-4015, USA; [email protected] 6 Division of Biological Science, Faculty of Science, Prince of Songkla University, Hat Yai 90110, Thailand * Correspondence: [email protected]; Tel.: +66-74-288-325 Abstract: The Songkhla Lake Basin (SLB) located in Southern Thailand, has been increasingly polluted by urban and industrial wastewater, while the lake water has been intensively used. Here, we aimed to investigate cyanobacteria and cyanotoxins in the SLB. Ten cyanobacteria isolates were identified as Microcystis genus based on16S rDNA analysis. All isolates harbored microcystin genes, while five of them carried saxitoxin genes. On day 15 of culturing, the specific growth rate and Chl-a content were 0.2–0.3 per day and 4 µg/mL. The total extracellular polymeric substances (EPS) content was Citation: Naknaen, A.; 0.37–0.49 µg/mL.
    [Show full text]
  • State of the Science for Cyanobacterial Blooms (Microcystis Species) in Florida a Summary Document from the 2019 Harmful Algal Bloom State of the Science Symposium
    State of the Science for Cyanobacterial Blooms (Microcystis species) in Florida A summary document from the 2019 Harmful Algal Bloom State of the Science Symposium Image: Cyanobacterial bloom in Lake Okeechobee Credit: L. Krimsky, Florida Sea Grant Contents: Introduction In recent years, intense blooms of Karenia brevis red tide and Introduction.....................................................2 Microcystis aeruginosa cyanobacteria, known commonly as Current Understanding.....................................3 blue-green algae, have plagued Florida waterways, impacting the state’s economy, environment and public health. Though Bloom Initiation, Development notable in their duration and intensity, these harmful algal and Termination...............................................3 blooms, or HABs, are not uncommon. Florida experiences a variety of HABs in its marine and fresh waters. Public Health....................................................4 Bloom Prediction and Modeling .......................5 In 2019, Governor Ron DeSantis’ Executive Order 19-12 established the Blue-Green Algae Task Force and revived the Bloom Detection and Monitoring......................5 state’s Harmful Algal Bloom Task Force to provide technical expertise and recommendations to reduce the adverse Bloom Mitigation and Control...........................6 impacts of future blooms. Next Steps........................................................6 This fact sheet represents the latest science-based Conclusion.......................................................6
    [Show full text]
  • Understanding the Interaction Between Anabaena Sp. and a Heterocyst-Specific Epibiont
    Understanding the interaction between Anabaena sp. and a heterocyst-specific epibiont Iglika V. Pavlova MBL Microbial Diversity course 2005 Abstract Anabaena sp. and an associated heterocyst-specific epibiontic bacterium were isolated from School Street Marsh in Woods Hole, MA in 1997 during the Microbial Diversity course. A two-member culture of the cyanobacterium and the epibiont have been maintained at WHOI by John Waterbury. Anabaena species with similar heterocyst-specific epibionts have also been isolated from other locations (7, 8, 9). Successful culture of the epibiont separately from the School Street Marsh cyanobacterium was achieved on two occasions (1, 10), but the isolates were not preserved. The epibiont was identified to be an α-proteobacterium within the Rhizobiaceae group (10). The close and specific association between the cyanobacterium and the epibiont strongly suggests there might be a physiological benefit or benefits to the cyanobacterium, the epibiont, or to both partners. This study was designed to understand the potential benefits of the interaction for the epibiontic bacterium. Several approaches were used to isolate the epibiont in pure culture, unsuccessfully. This report describes the rationale for undertaking the project and the approaches used to isolate the epibiont, in the hopes that this will be useful information for the future isolation of an axenic epibiont culture. Rationale Cyanobacterial associations with heterotrophic bacteria from environmental isolates have been described before and have been implicated in increasing the growth of the cyanobacterium (5, 6, 7). Benefit to the cyanobacterium may be derived from a range of associations, including the presence of heterotrophic bacteria in the culture medium, attraction of such bacteria to cyanobacterial secretions (either along the whole filament, or secretions stemming from the heterocyst in filamentous bacteria), or the attachment of the bacterium to the cyanobacterium outer surface (5, 6, 7, 9).
    [Show full text]
  • Planktothrix Agardhii É a Mais Comum
    Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters Catarina Isabel Prata Pereira Leitão Churro Doutoramento em Biologia Departamento Biologia 2015 Orientador Vitor Manuel de Oliveira e Vasconcelos, Professor Catedrático Faculdade de Ciências iv FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters The research presented in this thesis was supported by the Portuguese Foundation for Science and Technology (FCT, I.P.) national funds through the project PPCDT/AMB/67075/2006 and through the individual Ph.D. research grant SFRH/BD65706/2009 to Catarina Churro co-funded by the European Social Fund (Fundo Social Europeu, FSE), through Programa Operacional Potencial Humano – Quadro de Referência Estratégico Nacional (POPH – QREN) and Foundation for Science and Technology (FCT). The research was performed in the host institutions: National Institute of Health Dr. Ricardo Jorge (INSA, I.P.), Lisboa; Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), Porto and Centre for Microbial Resources (CREM - FCT/UNL), Caparica that provided the laboratories, materials, regents, equipment’s and logistics to perform the experiments. v FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters vi FCUP Accessing Planktothrix species diversity and associated toxins using quantitative real-time PCR in natural waters ACKNOWLEDGMENTS I would like to express my gratitude to my supervisor Professor Vitor Vasconcelos for accepting to embark in this research and supervising this project and without whom this work would not be possible. I am also greatly thankful to my co-supervisor Elisabete Valério for the encouragement in pursuing a graduate program and for accompanying me all the way through it.
    [Show full text]
  • Cylindrospermopsis Raciborskii. Retrieved From
    Cyanobacterium Cylindro I. Current Status and Distribution Cylindrospermopsis raciborskii (previously Anabaenopsis raciborskii) a. Range Global/Continental Wisconsin Native Range Great Lakes strain may have originated in South America1 Figure 1: U.S. Distribution Map2 Figure 2: Midwest Distribution Map2 Abundance/Range Widespread: Tropical and subtropical regions1 Not applicable Locally Abundant: Some temperate areas of northern Lake Michigan basin6, Lake hemisphere1; low levels of toxins Erie1, and a few southern reported in Indiana3 Wisconsin lakes; however there are no detectable toxins4 Sparse: Undocumented Undocumented Range Expansion Date Introduced: First described in Indonesian island of 1980’s or earlier4 Java, 19125 Rate of Spread: Rapid under optimal conditions; Rapid in temperate regions; 357,592 cells/mL in Lake Lemon, U.S. strain may have Indiana3 originated in South America1 Density Risk of Monoculture: High High Facilitated By: Warm temperature, eutrophic Warm temperature, eutrophic conditions conditions b. Habitat Lakes, reservoirs, streams, rivers, ponds, shallow systems Tolerance Chart of tolerances: Increasingly dark color indicates increasingly optimal range1,6,,,,,,7 8 9 10 11 12 Page 1 of 7 Wisconsin Department of Natural Resources – Aquatic Invasive Species Literature Review Preferences Low flow; low water level; low nitrogen to phosphorous ratio; high water temperature; stable thermal stratification; increased retention time; high pH; high sulfate concentration; anoxia in at least some strata; high turbidity; high incident irradiation; low macrophyte biomass1; high total phosphorus and chl-a3; requires high levels of reactive phosphorous13,14 c. Regulation Noxious/Regulated: Not regulated Minnesota Regulations: Not regulated Michigan Regulations: Not regulated Washington Regulations: Secondary Species of Concern II. Establishment Potential and Life History Traits a.
    [Show full text]
  • Anabaena Variabilis ATCC 29413
    Standards in Genomic Sciences (2014) 9:562-573 DOI:10.4056/sig s.3899418 Complete genome sequence of Anabaena variabilis ATCC 29413 Teresa Thiel1*, Brenda S. Pratte1 and Jinshun Zhong1, Lynne Goodwin 5, Alex Copeland2,4, Susan Lucas 3, Cliff Han 5, Sam Pitluck2,4, Miriam L. Land 6, Nikos C Kyrpides 2,4, Tanja Woyke 2,4 1Department of Biology, University of Missouri-St. Louis, St. Louis, MO 2DOE Joint Genome Institute, Walnut Creek, CA 3Lawrence Livermore National Laboratory, Livermore, CA 4Lawrence Berkeley National Laboratory, Berkeley, CA 5Los Alamos National Laboratory, Los Alamos, NM 6Oak Ridge National Laboratory, Oak Ridge, TN *Correspondence: Teresa Thiel ([email protected]) Anabaena variabilis ATCC 29413 is a filamentous, heterocyst-forming cyanobacterium that has served as a model organism, with an extensive literature extending over 40 years. The strain has three distinct nitrogenases that function under different environmental conditions and is capable of photoautotrophic growth in the light and true heterotrophic growth in the dark using fructose as both carbon and energy source. While this strain was first isolated in 1964 in Mississippi and named Ana- baena flos-aquae MSU A-37, it clusters phylogenetically with cyanobacteria of the genus Nostoc . The strain is a moderate thermophile, growing well at approximately 40° C. Here we provide some additional characteristics of the strain, and an analysis of the complete genome sequence. Introduction Classification and features Anabaena variabilis ATCC 29413 (=IUCC 1444 = The general characteristics of A. variabilis are PCC 7937) is a semi-thermophilic, filamentous, summarized in Table 1 and its phylogeny is shown heterocyst-forming cyanobacterium.
    [Show full text]
  • The Fate of Microcystins in the Environment and Challenges for Monitoring
    Toxins 2014, 6, 3354-3387; doi:10.3390/toxins6123354 OPEN ACCESS toxins ISSN 2072-6651 www.mdpi.com/journal/toxins Review The Fate of Microcystins in the Environment and Challenges for Monitoring Justine R. Schmidt 1,*, Steven W. Wilhelm 2 and Gregory L. Boyer 1 1 Department of Chemistry, College of Environmental Science and Forestry, State University of New York, Syracuse, NY 13210, USA; E-Mail: [email protected] 2 Department of Microbiology, University of Tennessee, Knoxville, TN 37996-0845, USA; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +1-315-470-6844; Fax: +1-315-470-6856. External Editor: Lesley V. D'Anglada Received: 1 November 2014; in revised form: 29 November 2014 / Accepted: 5 December 2014 / Published: 12 December 2014 Abstract: Microcystins are secondary metabolites produced by cyanobacteria that act as hepatotoxins in higher organisms. These toxins can be altered through abiotic processes, such as photodegradation and adsorption, as well as through biological processes via metabolism and bacterial degradation. Some species of bacteria can degrade microcystins, and many other organisms metabolize microcystins into a series of conjugated products. There are toxicokinetic models used to examine microcystin uptake and elimination, which can be difficult to compare due to differences in compartmentalization and speciation. Metabolites of microcystins are formed as a detoxification mechanism, and little is known about how quickly these metabolites are formed. In summary, microcystins can undergo abiotic and biotic processes that alter the toxicity and structure of the microcystin molecule. The environmental impact and toxicity of these alterations and the metabolism of microcystins remains uncertain, making it difficult to establish guidelines for human health.
    [Show full text]
  • Bacterial Community Composition of Size-Fractioned Aggregates Within the Phycosphere of Cyanobacterial Blooms in a Eutrophic Freshwater Lake
    Bacterial Community Composition of Size-Fractioned Aggregates within the Phycosphere of Cyanobacterial Blooms in a Eutrophic Freshwater Lake Haiyuan Cai1, Helong Jiang1*, Lee R. Krumholz2, Zhen Yang1 1 State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China, 2 Department of Botany and Microbiology, University of Oklahoma, Norman, Oklahoma, United States of America Abstract Bacterial community composition of different sized aggregates within the Microcystis cyanobacterial phycosphere were determined during summer and fall in Lake Taihu, a eutrophic lake in eastern China. Bloom samples taken in August and September represent healthy bloom biomass, whereas samples from October represent decomposing bloom biomass. To improve our understanding of the complex interior structure in the phycosphere, bloom samples were separated into large (.100 mm), medium (10–100 mm) and small (0.2–10 mm) size aggregates. Species richness and library coverage indicated that pyrosequencing recovered a large bacterial diversity. The community of each size aggregate was highly organized, indicating highly specific conditions within the Microcystis phycosphere. While the communities of medium and small-size aggregates clustered together in August and September samples, large- and medium-size aggregate communities in the October sample were grouped together and distinct from small-size aggregate community. Pronounced changes in the absolute and relative percentages of the dominant genus from the two most important phyla Proteobacteria and Bacteroidetes were observed among the various size aggregates. Bacterial species on large and small-size aggregates likely have the ability to degrade high and low molecular weight compounds, respectively. Thus, there exists a spatial differentiation of bacterial taxa within the phycosphere, possibly operating in sequence and synergy to catalyze the turnover of complex organic matters.
    [Show full text]
  • Umezakia Natans M.Watan. Does Not Belong to Stigonemataceae but To
    Fottea 11(1): 163–169, 2011 163 Umezakia natans M.WATAN . does not belong to Stigonemataceae but to Nostocaceae Yuko NIIYAMA 1, Akihiro TUJI 1 & Shigeo TSUJIMURA 2 1Department of Botany, National Museum of Nature and Science, 4–1–1 Amakubo, Tsukuba, Ibaraki 305–0005, Japan; e–mail: [email protected] 2Lake Biwa Environmental Research Institute, 5–34 Yanagasaki, Otsu, Shiga 520–0022, Japan Abstract: Umezakia natans M.WA T A N . was described by Dr. M. Watanabe in 1987 as a new species in the family of Stigonemataceae, following the rules of the Botanical Code. According to the original description, this planktonic filamentous species grows well in a growth media with pH being 7 to 9, and with a smaller proportion of sea water. Both heterocytes and akinetes were observed, as well as true branches developing perpendicular to the original trichomes in cultures older than one month. Watanabe concluded that Umezakia was a monotypic and only planktonic genus belonging to the family of Stigonemataceae. Unfortunately, the type culture has been lost. In 2008, we successfully isolated a new strain of Umezakia natans from a sample collected from Lake Suga. This lake is situated very close to the type locality, Lake Mikata in Fukui Prefecture, Japan. We examined the morphology of this U. natans strain, and conducted a DNA analysis using 16S rDNA regions. Morphological characters of the newly isolated strain were in a good agreement with the original description of U. natans. Furthermore, results of the DNA analysis showed that U. natans appeared in a cluster containing Aphanizomenon ovalisporum and Anabaena bergii.
    [Show full text]
  • Protein Phosphorylation and a Novel Phosphatase in the Cyanobacterium Anabaena
    Cyanobacteria 1 Running head: CYANOBACTERIA Protein Phosphorylation and a Novel Phosphatase in the Cyanobacterium Anabaena Robert Mullis A Senior Thesis submitted in partial fulfillment of the requirements for graduation in the Honors Program Liberty University Spring 2008 Cyanobacteria 2 Acceptance of Senior Honors Thesis This Senior Honors Thesis is accepted in partial fulfillment of the requirements for graduation from the Honors Program of Liberty University. _______________________________ L. Daniel Howell, Ph.D. Chairman of Thesis _______________________________ Mark Hemric, Ph.D. Committee Member _______________________________ Emily Heady, Ph.D. Committee Member _______________________________ Brenda Ayres, Ph.D. Honors Assistant Director _______________________________ Date Cyanobacteria 3 Abstract The focus of this paper is a dual-specific protein phosphatase (DSP) previously found in the periplasm of the cyanobacterium Anabaena PCC 7120 that may regulate circadian rhythms in that organism. To fully understand the topic, summaries of enzyme action, cyanobacteria, circadian rhythms, and phosphorylation cycles are required and therefore discussed in this report before the presentation of previous and current laboratory research centered on the phosphatase. A continuous cyanobacterial culture was maintained while cells were collected for harvesting periplasm. Tests to determine size, enzyme activity, and protein content were performed on the periplasm of the bacterial cells. Initial findings revealed at least one periplasmic protein
    [Show full text]
  • Zooming in on the Phycosphere: the Ecological Interface for Phytoplankton–Bacteria Relationships Justin R
    REVIEW ARTICLE PUBLISHED: 30 MAY 2017 | VOLUME: 2 | ARTICLE NUMBER: 17065 Zooming in on the phycosphere: the ecological interface for phytoplankton–bacteria relationships Justin R. Seymour1*, Shady A. Amin2,3, Jean-Baptiste Raina1 and Roman Stocker4 By controlling nutrient cycling and biomass production at the base of the food web, interactions between phytoplankton and bacteria represent a fundamental ecological relationship in aquatic environments. Although typically studied over large spa- tiotemporal scales, emerging evidence indicates that this relationship is often governed by microscale interactions played out within the region immediately surrounding individual phytoplankton cells. This microenvironment, known as the phycosphere, is the planktonic analogue of the rhizosphere in plants. The exchange of metabolites and infochemicals at this interface governs phytoplankton–bacteria relationships, which span mutualism, commensalism, antagonism, parasitism and competition. The importance of the phycosphere has been postulated for four decades, yet only recently have new technological and conceptual frameworks made it possible to start teasing apart the complex nature of this unique microbial habitat. It has subsequently become apparent that the chemical exchanges and ecological interactions between phytoplankton and bacteria are far more sophisticated than previously thought and often require close proximity of the two partners, which is facilitated by bacterial col- onization of the phycosphere. It is also becoming increasingly clear that while interactions taking place within the phycosphere occur at the scale of individual microorganisms, they exert an ecosystem-scale influence on fundamental processes including nutrient provision and regeneration, primary production, toxin biosynthesis and biogeochemical cycling. Here we review the fundamental physical, chemical and ecological features of the phycosphere, with the goal of delivering a fresh perspective on the nature and importance of phytoplankton–bacteria interactions in aquatic ecosystems.
    [Show full text]