A5064718190- Geophysics and Gravity Measurements
- Methane Hydrates and Related Phenomena
- Ionosphere and magnetosphere dynamics
- Seismic Waves and Analysis
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Microbial Community Ecology and Physiology
- Algal biology and biofuel production
- Marine and coastal ecosystems
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Genomics and Chromatin Dynamics
- Photosynthetic Processes and Mechanisms
- RNA and protein synthesis mechanisms
- Metabolomics and Mass Spectrometry Studies
- Mycorrhizal Fungi and Plant Interactions
- Biocrusts and Microbial Ecology
- Microbial Fuel Cells and Bioremediation
- Trace Elements in Health
- Plant Pathogens and Fungal Diseases
- Analytical Chemistry and Chromatography
- Mass Spectrometry Techniques and Applications
- Chromium effects and bioremediation
- Aquatic Ecosystems and Phytoplankton Dynamics
- RNA Research and Splicing
Lawrence Livermore National Laboratory
2015-2024
Scripps Institution of Oceanography
2008-2019
University of California, San Diego
2007-2019
Ludwig Cancer Research
2007-2008
Ludwig Cancer Research
2007
Cyanobacterial organic matter excretion is crucial to carbon cycling in many microbial communities, but the nature and bioavailability of this C depend on unknown physiological functions. Cyanobacteria-dominated hypersaline laminated mats are a useful model ecosystem for study flow complex as they use photosynthesis sustain more or less closed system. Although such have large reservoir extracellular polymeric substances (EPSs), production degradation not well defined. To identify processes...
Abstract Drought disrupts soil microbial activity and many biogeochemical processes. Although plant-associated fungi can support plant performance nutrient cycling during drought, their effects on nearby drought-exposed communities are not well resolved. We used H218O quantitative stable isotope probing (qSIP) 16S rRNA gene profiling to investigate bacterial community dynamics following water limitation in the hyphospheres of two distinct fungal lineages (Rhizophagus irregularis Serendipita...
Abstract Dinitrogen (N2)-fixation by cyanobacteria in symbiosis with feathermosses is the primary pathway of biological nitrogen (N) input into boreal forests. Despite its significance, little known about cyanobacterial gene repertoire and regulatory rewiring needed for establishment maintenance symbiosis. To determine acquisitions changes allowing to form maintain this symbiosis, we compared genomically closely related symbiotic-competent -incompetent Nostoc strains using a proteogenomics...
Subsurface chlorophyll maximum layers (SCMLs) are nearly ubiquitous in stratified water columns and exist at horizontal scales ranging from the submesoscale to extent of oligotrophic gyres. These heightened and/or phytoplankton concentrations generally thought be a consequence balance between light energy above limiting nutrient flux below, typically nitrate (NO 3 ). Here we present multiple lines evidence demonstrating that iron (Fe) limits or with colimits communities SCMLs along primary...
In nitrogen-limited boreal forests, associations between feathermoss and diazotrophic cyanobacteria control nitrogen inputs thus carbon cycling, but little is known about the molecular regulators required for initiation maintenance of these associations. Specifically, a benefit to not known, challenging whether association nutritional mutualism. Targeted mutagenesis cyanobacterial alkane sulfonate monooxygenase results in an inability colonize feathermosses by cyanobacterium Nostoc...
Bacterial remineralization of algal organic matter fuels growth but is rarely quantified. Consequently, we cannot currently predict whether some bacterial taxa may provide more remineralized nutrients to algae than others. Here, quantified incorporation algal-derived complex dissolved carbon and nitrogen in fifteen co-cultures growing with the diatom Phaeodactylum tricornutum at single-cell level using isotope tracing nanoSIMS. We found unexpected strain-to-strain cell-to-cell variability...
Roles of different ecological classes algal exometabolites in regulating microbial community composition are not well understood. Here, we identify from the model diatom Phaeodactylum tricornutum and demonstrate their potential to influence bacterial abundances. We profiled across a time course axenic growth using liquid chromatography-tandem mass spectrometry. then investigated 12 isolates on individual-identified exometabolites. Lastly, compared responses P. tricornutum-adapted enrichment...
Copper appears to be influencing the distribution and abundance of phytoplankton in marine environments, cyanobacteria are thought most sensitive groups copper toxicity. By using growth assays phylogenetically divergent clades, we found that coastal strains Synechococcus species were more tolerant shock than open-ocean strains. The global transcriptional response two levels determined for both a strain an whole-genome expression microarrays. Both showed osmoregulatory-like response, perhaps...
Abstract Dust is an important iron (Fe) source to the ocean, but its utilization by phytoplankton constrained rapid sinking and slow dissolution dust-bound (dust-Fe). Colonies of globally cyanobacterium, Trichodesmium, overcome these constraints efficient dust capturing active dust-Fe dissolution. In this study we examined ability Trichodesmium colonies maximize their Fe supply from selectively collecting Fe-rich particles. Testing for selectivity in particle collection, supplied ~600...
Dissolved exometabolites mediate algal interactions in aquatic ecosystems, but microalgal exometabolomes remain understudied. We conducted an untargeted metabolomic analysis of nonpolar exuded from four phylogenetically and ecologically diverse eukaryotic strains grown the laboratory, freshwater Chlamydomonas reinhardtii, brackish Desmodesmus sp., marine Phaeodactylum tricornutum, Microchloropsis salina, to identify released metabolites based on relative enrichment compared cell pellet...
AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout JournalEditorsTheme Sections 4:117-133 (2013) - DOI: https://doi.org/10.3354/aei00078 Ecosystem modelling for ecosystem-based management of bivalve aquaculture sites in data‑poor environments R. Filgueira1,3,*, J. Grant1, Stuart2, M. S. Brown1 1Department Oceanography, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada 2PO...
The gene encoding the cyanobacterial ferritin SynFtn is up-regulated in response to copper stress. Here, we show that, while does not interact directly with copper, it highly unusual several ways. First, its catalytic diiron ferroxidase center unlike those of all other characterized prokaryotic ferritins and instead resembles an animal H-chain center. Second, as demonstrated by kinetic, spectroscopic, high-resolution X-ray crystallographic data, reaction O2 di-Fe2+ results a direct,...
Although it is becoming clear that many microbial primary producers can also play a role as organic consumers, we know very little about the metabolic regulation of photoautotroph matter consumption. Cyanobacteria in phototrophic biofilms reuse extracellular carbon, but drivers processes are surprisingly complex. We investigated foundations by comparing exoproteome composition and incorporation (13)C-labeled (15)N-labeled cyanobacterial (EOM) unicyanobacterial biofilm incubated using...
Marine microorganisms, particularly those residing in coastal areas, may come contact with any number of chemicals environmental or xenobiotic origin. The sensitivity and response marine cyanobacteria to such is, at present, poorly understood. We have looked the transcriptional well characterized Synechococcus open ocean (WH8102) (CC9311) isolates two DNA damaging agents, mitomycin C ethidium bromide, using whole-genome expression microarrays. strain showed differential regulation a larger...
Abstract Background Osmotic stress is caused by sudden changes in the impermeable solute concentration around a cell, which induces instantaneous water flow or out of cell to balance concentration. Very little known about detailed response mechanism osmotic marine Synechococcus , one major oxygenic phototrophic cyanobacterial genera that contribute greatly global CO 2 fixation. Results We present here computational study osmoregulation network hyperosmotic sp strain WH8102 using comparative...
Phylogenetically closely related bacteria can thrive in diverse environmental habitats due to adaptive evolution. Genomic changes resulting from evolution lead variations cellular function, metabolism, and secondary metabolite biosynthesis.
Picocyanobacteria from the genus Synechococcus are ubiquitous in ocean waters. Their phylogenetic and genomic diversity suggests ecological niche differentiation, but selective forces influencing this not well defined. Marine picocyanobacteria sensitive to Cu toxicity, so adaptations stress could represent a force within, between, 'species', also known as clades. Here, we compared responses cultures natural populations of marine two co-occurring major mesotrophic clades (I IV). Using custom...