2008 Center for Microbial Oceanography Research and Education (CMORE) Summer Course “Microbial Oceanography Genomes to Biomes” Student Symposium, June 6th, 2008 University of Hawaii

2008 Center for Microbial Oceanography: Research and Education CMORE Summer Course “Microbial Oceanography: Genomes to Biomes” Student Symposium, June 6th, 2008 University of Hawaii Reb

2008 Center for Microbial Oceanography:

Research and Education (CMORE) Summer Course “Microbial Oceanography: Genomes to Biomes”

Student Symposium, June 6th, 2008

University of Hawaii

Rebecca Case Harvard University Sophie Clayton MIT/WHOI Joint Program Alejandro Andrés Murillo Córdova Pontificia Universidad Católica de Chile

Li Deng The University of Bristol Caroline Fortunato University of Maryland Melissa Laghdass CNRS/UMR-France Christopher Reisch University of Georgia Claudia Hernandez Rondón Estación de Fotobiología Playa Unión-Argentina

Sandra Schöttner Max Planck Institute for Marine Microbiology Christine Shulse Scripps Institution of Oceanography

Yuna Seo The University of Tokyo Nellie Shaul Scripps Institution of Oceanography Danielle Morgan-Smith Old Dominion University

Elena Stoica University of Liverpool Frank K Thomson, III Old Dominion University Laure-Anne Ventouras Massachusetts Institute of Technology

REBECCA CASE

AFFILIATION: Harvard University

TITLE: Bacterial-algal interactions and the sulfur cycle

ABSTRACT:

Algae produce and store the major biogenic source of sulfur in the marine environment,

dimethylsulfoniopropionate (DMSP) DMSP is an osmolyte in algae and is made accessible for microbial degradation in the ocean through lysis of algal cells DMSP is degraded by bacteria through the demethylation/demethiolation pathway or the cleavage pathway The former

pathway degrades DMSP to sulfate, while the latter pathways product is dimethyl sulfide (DMS) DMS is an important intermediate in the sulfur cycle and influences climate through the

formation of cloud condensation nuclei (CCN) Model calculations have shown a (theoretical) negative feedback between DMS producing communities and global mean temperature,

suggesting these communities could play a role in climate

SOPHIE CLAYTON

AFFILIATION: MIT/WHOI Joint Program

TITLE: Investigating controls on the seasonal cycle of /Synechococcus/ biomass

at MVCO using a simple box model

ABSTRACT:

It is generally thought that the interaction of physical and biological processes in the open ocean results in a relatively constant background of small phytoplankton cells This has not, however, been fully investigated in coastal ecosystems Recent observations from the

Martha's Vineyard Coastal Observatory (MVCO), made using an automated submersible flow cytometer, have shown that this does not seem to be the case there (Sosik & Olson, 2006) Time series of picoplankton biomass, comprised mainly of /Synechococcus/ and picoeukaryotes, from

2003 to the present, show that there is an increase in picoplankton biomass in the spring,

sustained throughout the summer, followed by a decrease in the autumn Temperature has been suggested to play a role in limiting growth during the winter months, but the combination of physical and biological processes operating to regulate picoplankton biomass during the spring and autumn transition periods is not well understood The aim of this study, therefore, is to use a simple box model which incorporates temperature-dependent growth, nutrient limitation and a closure term representing the sum of all loss processes to Synechococcus (e.g grazing, mortality, advection,etc ) to investigate the controls on these seasonal variations at MVCO The model is optimized to find the parameters which best fit the observations, and the model-data misfit assessed quantitatively The structure of the model is modified, and the subsequent model-data misfits compared, to test hypotheses about which environmental factors control the seasonal cycle of /Synechococcus/ biomass

ALEJANDRO ANDRÉS MURILLO CÓRDOVA

AFFILIATION: Pontificia Universidad Católica de Chile

TITLE: Cylindrospermopsis raciborskii has model organism for PSP toxins pathway synthesis

study

ABSTRACT:

In Chile, annually in summer an algal bloom (red tide) occur in the sea in austral regions and the

microorganism responsible is the dinoflagellate Alexandrium Catenella a eukaryotic microalga

that produce saxitoxin (STX) and their analogs, this neurotoxins act blocking the voltage gate sodium channel and can be accumulated by bivalves, producing the “Paralytic Shellfish

Poisoning” (PSP) syndrome In the case of fresh water sources the algal blooms with de

concomitant toxin contamination are produced by cyanobacteria Cyanobacteria are

photosynthetic bacteria that are capable of produce a wide variety of injurious compounds toxics

or irritants The species of cyanobacteria that are STX producers are Aphanizomenon flos-aquae,

Anabaena circinalis, Lyngbya wollei, Cylindrospermopsis raciborskii and Planktothrix agardhii.

The pathway of synthesis of STX or genes related with the toxin remains unknown for all the producer organisms, but we know that the precursors are the same for cyanobacteria and

dinoflagellate Among the STX producers microorganisms the cyanobacteria are de best model

of study, especially de specie Cylindrospermopsis raciborskii, because it has strains that produce

toxin; STX and their analogs or cylindrospermopsin and strains non toxin producers and all the strain are genetically homogeneous Our objective is to characterize the toxin producer strains genetically and functionally to identified de enzymatic machinery involved in STX production

LI DENG

AFFILIATION: The University of Bristol

TITLE: The role of cyanophages in regulating bloom-forming freshwater cyanobacteria

ABSTRACT:

Cyanobacteria are important and diverse members of aquatic systems both in marine and

freshwater environments Cyanobacterial viruses (cyanophages) in marine systems have been shown to play roles in mortality of their hosts, as well as driving evolution of core metabolic functions even photosynthesis Thus I wondered what roles cyanophages might play in

freshwater systems where cyanobacterial genera were predominately filamentous and bloom-forming, rather than unicellular non-bloom-forming cells To this end, I used multiple genetic loci (T4-phage portal protein, major capsid protein) to gain an overall understanding of the phylogenetic diversity of these genes within natural phage communities in a couple of European lakes I next isolated 35 cyanophages that infect bloom-forming freshwater cyanobacteria (Microcystis, Anabaena and Planktothrix) using viral-fraction waters from Lake Zurich,

Switzerland and lakes in the Cotswold Water Park, U.K Morphological characterization

revealed a variety of morphotypes, including commonly observed tailed phage morphotypes (e.g., podo-, myo-, siphoviruses), as well as the first filamentous cyanophage Host range characterization showed that some cyanophages were capable of infecting cyanobacterial hosts across three genera The ability to infect a wide range of host taxa which dominant water bodies

in variable depth and variable time extends the potential reproductive period for lytic

propagation of cyanophages, and also has implications for the transfer of genetic information between phylogenetically disparate cyanobacterial lineages A primary example of such viral-mediated HGT might be the discovery of a phycocyanin gene previously thought to be

horizontally transferred in the host cells and was found in a cyanophage isolate A-CP1 by PCR screen with substantive controls to minimize the probability of amplifying a host gene

Phycocyanin is ubiquitous accessory photosynthesis gene thought to be important in host

metabolism during phage infection, but also previously hypothesized to have been horizontally transferred is my phage a smoking gun for a mechanism?

CAROLINE FORTUNATO

AFFILIATION: University of Maryland

TITLE: Microbial community observation and prediction in the Columbia River, its estuary and

the adjacent coastal ocean

ABSTRACT:

Microbial communities are dynamic and vary over many environmental gradients The goal of this study is to determine the composition of the microbial communities of the Columbia River system and how the different populations of this community are distributed from river to estuary and across the coastal ocean A 16S rRNA gene based microbial community record will be created using the community fingerprinting technique, denaturing gradient gel electrophoresis (DGGE) Once a map of microbial communities is established, shifts in the distribution of individual microbial populations over space and time will then be connected with environmental factors and linked to forecast models of coastal margin environmental conditions Currently, cruise data from August 2007 is being used to construct a system-wide map of microbial

population distributions, with future plans to examine seasonal and interannual changes in these populations

MELISSA LAGHDASS

AFFILIATION: CNRS/UMR France

TITLE: External sources of organic carbon in marine oligotrophic environment: degradation by

different functional and phylogenetic groups of the heterotrophic prokaryotes and impact on the metabolic balance

ABSTRACT:

The metabolic balance (ration between respiration and production of the organic matter) depends directly of the ecosystem functioning Studies suggest that the respiration exceed the production

in the oligotrophic ocean causing a visible deficit of organic carbon This deficit can be explain either by a decoupling between production and respiration or by an external source of organic matter that would provide the respiration A temporal monitoring of this deficit is also essential

in order to understand the origin of this deficit Besides, the heterotrophic prokaryotes contribute

to the essential of the respiration in the oligotrophic environment Their metabolic activity plays also a key role in the metabolic balance The variability of the prokaryotic respiration depends essentially of the bioavailability of organic matter and the nutrient concentration Furthermore, the nature of organic matter would play a role in the presence and activity of phylogenetic groups The identification of these groups is very important in order to understand their role in the metabolic balance In situ observations started in the NW Mediterranean Sea (MOLA station) on February 2007 Samples are carrying out once a month to determine the metabolic balance and identify the phylogenetic prokaryotes of heterotrophic prokaryotes The metabolic balance is evaluated by winckler method Using molecular biology, oligonucleotidic probes specific of bacterial groups or target probes will create So, by combining microautoradiography and in situ hybridization from created probes, activity of these groups could determine An experimental approach based on the chemostat culture is too envisaged to know the response of different bacterial groups according to the sources of organic matter

CHRISTOPHER REISCH

AFFILIATION: University of Georgia

TITLE: Purification and Characterization of DMSP Dependent Demethylase (DmdA) from

icMarine Bacteria

ABSTRACT:

The algal metabolite dimethylsulfoniopropionate (DMSP) is ubiquitous in marine environments, ranging in concentration from 5-200 nM in surface waters DMSP is the precursor of the volatile compound dimethylsulfide, whh is the primary natural source of sulfur in the atmosphere Degradation of DMSP occurs through two competing pathways, yielding DMS in the cleavage pathway or methanethiol through the demethylation pathway Recently, the enzyme responsible for the demethylation of DMSP, designated DmdA, was discovered in two marine isolates, Silicibacter pomeroyi DSS-3 and Pelagibacter ubique HTCC1062 To further our understanding

of DMSP demethylation, recombinant DmdA from P ubique was purified The purified enzyme exhibited strict substrate specificity for DMSP The apparent Vmax of DmdA was 7.6µmols min-1 mg-1 with an apparent Km for DMSP of 11.5 mM In cell extracts of S pomeroyi DSS-3 the apparent Km for DMSP was 10.2 mM, similar to that of purified recombinant DmdA The intracellular concentration of DMSP in chemostat-grown S pomeroyi DSS-3 was found to range from 66-93 mM, depending on growth conditions These results suggest that cells actively accumulate DMSP as an osmolyte Moreover, initiation of DMSP demethylation by DmdA only occurs at very high intracellular concentrations

CLAUDIA HERNÁNDEZ RONDÓN

AFFILIATION: Estación de Fotobiología Playa Unión-Argentina

Title: Solar radiation effects on bacterioplankton of Patagonia.

ABSTRACT:

The decrease on stratospheric Ozone levels and the rise of incident solar radiation (mainly on UVB range) affects aquatic systems Even under normal levels, solar and UVB radiation

generates variety of responses (typically deleterious) on metabolic activity, physiology and diversity of microorganisms Therefore, the bacterioplankton response is related with light penetration and with biogeochemical composition of each ecosystem Chubut area (43° S, Argentinean Patagonia) possesses strong winds that turn in low cloud cover and consequently high levels of solar radiation along the year A decade of punctual studies at this zone evidenced the impact of solar radiation (PAR and UVR).At the Chubut River “mouth” there is high primary and fishery production present Photoinhibition and repair processes related to cell size were reported mainly for phytoplankton In the case of heterotrophic bacteria, there are not internal protection mechanisms to deal with solar stress I developed punctual experiments at the pier with river and seawater (according to tides) along summer Previous results showed mainly UVB effects on bacterioplankton abundance, and growth At the same time samples to check bacterial diversity changes by solar stress are a work on progress

SANDRA SCHÖTTNER

AFFILIATION: Max Plank Institute for Marine Microbiology

TITLE: Microbial habitats in cold-water coral reef ecosystems

ABSTRACT:

The potential of key ecosystems like cold-water coral reefs to foster enhanced species diversity

in the ocean is undisputed However, little is known about the putative role that cold-water coral reefs play as biodiversity hotspots for the “unseen majority” in the oceans: prokaryotic

communities Our current efforts evolve around the central question, if cold-water corals act as ecosystem engineers in their reef environment by shaping microbial diversity, activity and functionality via habitat differentiation and release of organic matter Pilot studies in 2006/2007 revealed that bacterial communities may associate very specifically with distinct microbial

habitats generated by the reef-building coral Lophelia pertusa, such as the coral skeleton surface,

mucus and tissue when compared to ambient sediments and seawater In particular, coral mucus was characterized by distinct and very diverse bacterial patterns, and has shown to act as possible energy vector from corals to microbes in reef waters Whether these trends have a general

validity for cold-water coral reef ecosystems is currently under investigation in more extensive studies targeting the diversity, dynamics and potential function of prokaryotes along horizontal and vertical gradients in different reef systems off Northern Norway and Chile