A5085731355- Microbial Community Ecology and Physiology
- Marine and coastal ecosystems
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Marine Biology and Ecology Research
- Aquatic Ecosystems and Phytoplankton Dynamics
- Microbial Fuel Cells and Bioremediation
- Isotope Analysis in Ecology
- Folate and B Vitamins Research
- Alcoholism and Thiamine Deficiency
- Wastewater Treatment and Nitrogen Removal
- Algal biology and biofuel production
- Geochemistry and Elemental Analysis
- Methane Hydrates and Related Phenomena
- Marine Bivalve and Aquaculture Studies
- Ocean Acidification Effects and Responses
- Metabolism and Genetic Disorders
- Metal Extraction and Bioleaching
- Porphyrin Metabolism and Disorders
- Epigenetics and DNA Methylation
- Legume Nitrogen Fixing Symbiosis
- Physiological and biochemical adaptations
- Microbial Natural Products and Biosynthesis
- Biocrusts and Microbial Ecology
- Chemistry and Stereochemistry Studies
University of Southern California
2016-2025
Southern California University for Professional Studies
2009-2025
Woods Hole Oceanographic Institution
2002-2009
Furman University
2007
University of Wisconsin–Madison
1996-2000
Aerospace Technology Institute
1998
Louisiana State University Agricultural Center
1997
Oak Ridge National Laboratory
1974-1978
International Union of Pure and Applied Chemistry
1975
Roche (Switzerland)
1975
Abstract. Marine N2 fixing microorganisms, termed diazotrophs, are a key functional group in marine pelagic ecosystems. The biological fixation of dinitrogen (N2) to bioavailable nitrogen provides an important new source for ecosystems and influences primary productivity organic matter export the deep ocean. As one series efforts collect biomass rates specific different phytoplankton groups, we have constructed database on diazotrophic organisms global upper ocean by compiling about 12 000...
I. Fatty acids, neutral fats, long-chain alcohols and bases A. Generic terms (Lip-1.1 -1.5).B. Individual compounds .1. acids (Lip-1.6 -1.7) .2. Sphinganine derivatives (Lip-1.8 -1.11) 3. Glycerol (Lip-1.12-1.13) C. Symbols abbreviations (Lip-1.14-1.18).II.Phospholipids.A. (Lip-2.1 -2.10) B. (Lip-2.11 -2.12) III.Glycolipids.A. General considerations (Lip-3.1 -3.5) .C. (Lip-3.6 -3. 12).D. (Lip-3.12 -3.14).IV.Neuraminic acid (Lip-4.1 -4.3).Appendix A: names of symbols for higher fatty acids.
B vitamins are some of the most commonly required biochemical cofactors in living systems. Therefore, cellular metabolism marine vitamin-requiring (auxotrophic) phytoplankton and bacteria would likely be significantly compromised if (thiamin 1 , riboflavin 2 pyridoxine 6 biotin 7 cobalamin 12 ) were unavailable. However, factors controlling synthesis, ambient concentrations, uptake these key organic compounds environment still not well understood. Here, we report vertical distributions five...
Abstract Nitrogen fixation rates of the globally distributed, biogeochemically important marine cyanobacterium Trichodesmium increase under high carbon dioxide (CO 2 ) levels in short-term studies due to physiological plasticity. However, its long-term adaptive responses ongoing anthropogenic CO increases are unknown. Here we show that experimental evolution extended selection at projected future elevated results irreversible, large nitrogen and growth rates, even after being moved back...
Mariprofundus ferrooxydans PV-1 has provided the first genome of recently discovered Zetaproteobacteria subdivision. Genome analysis reveals a complete TCA cycle, ability to fix CO2, carbon-storage proteins and sugar phosphotransferase system (PTS). The latter could facilitate transport carbohydrates across cell membrane possibly aid in stalk formation, matrix composed exopolymers and/or exopolysaccharides, which is used store oxidized iron minerals outside cell. Two-component signal...
The genus of Marinobacter is one the most ubiquitous in global oceans and assumed to significantly impact various biogeochemical cycles. genome structure content aquaeolei VT8 was analyzed compared with those from other organisms diverse adaptive strategies. Here, we report many "opportunitrophic" genetic characteristics strategies that M. has adopted promote survival under environmental conditions. Genome analysis revealed its metabolic potential utilize oxygen nitrate as terminal electron...
ABSTRACT Natural products are a functionally diverse class of biochemically synthesized compounds, which include antibiotics, toxins, and siderophores. In this paper, we describe both the detection natural product activities sequence identification gene fragments from two molecular systems that have previously been implicated in production, i.e., nonribosomal peptide synthetases (NRPSs) modular polyketide synthases (PKSs), marine freshwater cyanobacterial cultures. Using degenerate PCR...
Cyanobacteria are prominent constituents of the marine biosphere that account for a significant percentage oceanic primary productivity. In an effort to resolve how open-ocean cyanobacteria persist in regions where Fe concentration is thought be limiting their productivity, we performed number stress experiments on axenic cultures Synechococcus spp., Crocosphaera sp., and Trichodesmium sp. Through this work, determined all these mount adaptive responses stress, which resulted induction...
The marine diazotroph Trichodesmium is a major contributor to primary production and nitrogen fixation in the tropical subtropical oceans. These regions are often characterized by low phosphorus (P) concentrations, P starvation of could limit growth, potentially constrain fixation. To better understand how this genus responds we examined four genes involved acquisition: two copies high-affinity phosphate binding protein (pstS sphX) putative alkaline phosphatases (phoA phoX). Sequence...
Diazotrophic cyanobacteria have long been recognized as important sources of reduced nitrogen (N) and therefore are ecosystem components. Until recently, species the filamentous cyanobacterium Trichodesmium were thought to be primary fixed N open ocean euphotic zone. It is now that unicellular also contributors, with members oligotrophic genus Crocosphaera being only cultured examples. Herein we genetically phenotypically characterize 10 strains isolated from tropical Atlantic North Pacific...
Trichodesmium spp. play key roles in global carbon and nitrogen budgets thus defining what controls their productivity is important for understanding climate change. While iron availability has been shown to be an chemical factor controlling both growth fixation rates Trichodesmium, all culture experiments date have focused solely on representatives from one clade of Trichodesmium. Genomic sequence analysis determined that the erythraeum (IMS101) genome contains many archetypical genes...
Axenic cultures of the N 2 ‐fixing marine cyanobacterium Crocosphaera watsonii exhibit very high B 12 excretion rates (up to 40 times higher per cell), compared smaller non‐N strain Synechococcus . The effect availability on vitamin synthesis is also evident in non‐diazotrophic strain, as they release five more under N‐replete conditions relative N‐limiting conditions, although this value still an order magnitude than amount produced by diazotroph. cyanobacterial contribution oceanic supply...
[1] Dinitrogen (N2) fixation is recognized as an important input of new nitrogen (N) to the open ocean gyres, contributing export organic matter from surface waters. However, very little N2-fixation research has focused on South Atlantic Gyre, where dust deposition iron (Fe), micronutrient for diazotrophs, seasonally low. Recent modeling efforts suggest that may in fact be closely coupled to, and greatest in, areas denitrification, opposed oceanic gyres. One these areas, Benguela Upwelling...
Abstract Nitrogen fixation by cyanobacteria supplies critical bioavailable nitrogen to marine ecosystems worldwide; however, field and lab data have demonstrated it be limited iron, phosphorus and/or CO 2 . To address unknown future interactions among these factors, we grew the nitrogen-fixing cyanobacterium Trichodesmium for 1 year under Fe/P co-limitation following 7 years of both low high selection. co-limited cell lines a complex cellular response including increased growth rates, broad...