A5020312707- Microbial Community Ecology and Physiology
- Groundwater flow and contamination studies
- Radioactive element chemistry and processing
- Genomics and Phylogenetic Studies
- Coastal wetland ecosystem dynamics
- Radioactive contamination and transfer
- Methane Hydrates and Related Phenomena
- Wastewater Treatment and Nitrogen Removal
- Groundwater and Isotope Geochemistry
- Microbial bioremediation and biosurfactants
- Hydrocarbon exploration and reservoir analysis
- Algal biology and biofuel production
- Analytical chemistry methods development
- Hydraulic Fracturing and Reservoir Analysis
- Water Treatment and Disinfection
- Geophysical Methods and Applications
- Environmental DNA in Biodiversity Studies
- Radioactivity and Radon Measurements
- Legume Nitrogen Fixing Symbiosis
- CO2 Sequestration and Geologic Interactions
- Mine drainage and remediation techniques
- Corrosion Behavior and Inhibition
- Trace Elements in Health
- Microbial Fuel Cells and Bioremediation
- Environmental remediation with nanomaterials
Pacific Northwest National Laboratory
2018-2025
Massachusetts Institute of Technology
2024
Savannah River National Laboratory
2006-2023
United States Department of Energy
2018
Battelle
2018
University of South Carolina
1998-2010
University of South Carolina Aiken
2009
Oak Ridge National Laboratory
2003-2006
Miami University
2006
Stanford University
2006
ABSTRACT Despite the ubiquity of ammonium in geothermal environments and thermodynamic favorability aerobic ammonia oxidation, thermophilic ammonia-oxidizing microorganisms belonging to crenarchaeota kingdom have only recently been described. In this study, we analyzed microbial mats surface sediments from 21 hot spring samples (pH 3.4 9.0; temperature, 41 86°C) United States, China, Russia obtained 846 putative archaeal monooxygenase large-subunit ( amoA ) gene transcript sequences,...
ABSTRACT N 2 fixation by diazotrophic bacteria associated with the roots of smooth cordgrass, Spartina alterniflora , is an important source new nitrogen in many salt marsh ecosystems. However, diversity and phylogenetic affiliations these rhizosphere diazotrophs are unknown. Denaturing gradient gel electrophoresis (DGGE) PCR-amplified nifH sequence segments was used previous studies to examine stability dynamics diazotroph assemblages North Inlet marsh, near Georgetown, S.C. In this study,...
Pseudomonas putida strain AJ and Ochrobactrum TD were isolated from hazardous waste sites based on their ability to use vinyl chloride (VC) as the sole source of carbon energy under aerobic conditions. Strains also ethene ethylene oxide growth substrates. Strain contained a linear megaplasmid (approximately 260 kb) when grown VC or ethene, but it no circular plasmids. While was growing oxide, observed contain 100-kb plasmid, its substrate retained. The plasmids in cured, consume VC, lost...
The detection and identification of microorganisms in natural communities is a great challenge to biologists. Microarray-based genomic technology provides promising high-throughput alternative traditional microbial characterization. A novel prototype microarray containing whole DNA, termed community genome array (CGA), was constructed evaluated. Microarray hybridizations at 55 °C using 50% formamide permitted the examined bacteria be distinguished species level, while strain-level...
Precision measurements by the Alpha Magnetic Spectrometer (AMS) on International Space Station of deuteron (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>D</a:mi></a:mrow></a:math>) flux are presented. The based <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mn>21</c:mn><c:mo>×</c:mo><c:msup><c:mrow><c:mn>10</c:mn></c:mrow><c:mrow><c:mn>6</c:mn></c:mrow></c:msup></c:mrow></c:math> <e:math...
ABSTRACT Rhizosphere diazotroph assemblages of salt marsh grasses are thought to be influenced by host plant species and a number porewater geochemical parameters. Several variables can adversely affect productivity spatial distributions, resulting in strong zonation growth forms. This geochemically induced stress may also influence the compositions distributions rhizosphere assemblages, but little is currently known about these organisms. The diversity key physiological features culturable,...
Denaturing gradient gel electrophoresis (DGGE) was employed to resolve PCR-amplified nifH sequences from vegetated and unvegetated sediments two oligotrophic seagrass bed sites on San Salvador Island, Bahamas, in order assess diazotroph species composition. All DGGE profiles these showed the same prominent bands. These bands were sequenced, yielding 67 different sequences, which used phylogenetic reconstructions. Most anaerobes, but some affiliated with alpha- (gamma-+beta-) Proteobacteria....
Kineococcus radiotolerans SRS30216 was isolated from a high-level radioactive environment at the Savannah River Site (SRS) and exhibits gamma-radiation resistance approaching that of Deinococcus radiodurans. The genome sequenced by U.S. Department Energy's Joint Genome Institute which suggested existence three replicons, 4.76 Mb linear chromosome, 0.18 plasmid, 12.92 Kb circular plasmid. Southern hybridization confirmed chromosome is linear. K. sequence examined to learn about physiology...
ABSTRACT DNA was extracted from dry standing dead Spartina alterniflora stalks as well wrack the North Inlet (South Carolina) and Sapelo Island (Georgia) salt marshes. Partial nifH sequences were PCR amplified, products separated by denaturing gradient gel electrophoresis (DGGE), prominent DGGE bands sequenced. Most (109 of 121) clustered with those α- Proteobacteria , 4 very similar (>99%) to that Azospirillum brasilense . Seven known γ- five anaerobic diazotrophs. The diazotroph...
1,2-Dichloroethane (1,2-DCA) and 1,2-dibromoethane (ethylene dibromide [EDB]) contaminate groundwater at many hazardous waste sites. The objectives of this study were to measure yields, maximum specific growth rates (μ), half-saturation coefficients (K(S)) in enrichment cultures that use 1,2-DCA EDB as terminal electron acceptors lactate the donor evaluate if presence has an effect on kinetics dehalogenation vice versa. Biodegradation was evaluated high concentrations found some industrial...
ABSTRACT Rhizoplane-rhizosphere nitrogen-fixing microorganisms (diazotrophs) are thought to provide a major source of biologically available nitrogen in salt marshes dominated by Spartina alterniflora . Compositional and functional stability has been demonstrated for this important group; however, the quantitative responses specific diazotroph populations environmental variability have not assessed. Changes relative abundances selected rhizoplane diazotrophs response long-term fertilization...
ABSTRACT This study examined the natural diversity and distributions of sulfate-reducing bacteria along a carbon gradient extending down shelf-slope transition zone eastern Pacific continental margin. Dissimilatory (bi)sulfite reductase gene sequences ( dsrAB ) were PCR amplified cloned from five different sampling sites, each at discrete depth, two margin systems, one off coast Mexico another Washington State. A total 1,762 clones recovered evaluated by restriction fragment length...
ABSTRACT Genomic techniques commonly used for assessing distributions of microorganisms in the environment often produce small sample sizes. We investigated artificial neural networks analyzing nitrite reductase genes ( nirS and nirK ) two sets dissimilatory sulfite dsrAB 1 2 sets. Data reduction (to reduce number input parameters), cross-validation measure generalization error), weight decay adjust model parameters to importance analysis determine which variables had most influence) were...
Few studies have demonstrated changes in community structure along a contaminant plume terms of phylogenetic, functional, and geochemical changes, such are essential to understand how microbial ecosystem responds perturbations. Clonal libraries multiple genes (SSU rDNA, nirK, nirS, amoA, pmoA, dsrAB) were analyzed from groundwater samples (n = 6) that varied levels, 107 parameters measured. Principal components analyses (PCA) used compare the relationships among sites with respect biomarker...
Microalgae could become an important resource for addressing increasing global demand food, energy, and commodities while helping to reduce atmospheric greenhouse gases. Even though Chlorophytes are generally regarded safe human consumption, there is still much we do not understand about the metabolic biochemical potential of microscopic algae. The aim this study was evaluate biofuel candidate strains Chlorella Scenedesmus produce bioactive metabolites when grown under nutrient depletion...
Five strains representing a novel family within the Gammaproteobacteria were isolated from estuarine grasses Spartina alterniflora and Juncus roemerianus. All facultatively anaerobic, Gram-negative, short, motile, polar monotrichous rods that mesophilic, oxidase-negative, catalase-positive, had DNA G+C contents of 41.5-44.4 mol% required seawater salts or NaCl. Growth was observed at pH 3.5-8.0. Polar lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine,...
ABSTRACT The actinobacterium Kineococcus radiotolerans is highly resistant to ionizing radiation, desiccation, and oxidative stress, though the underlying biochemical mechanisms are unknown. purpose of this study was explore a possible linkage between uptake transition metals extreme resistance radiation stress. effects six different divalent cationic on growth were examined in absence radiation. None tested stimulatory, cobalt inhibitory growth. In contrast, copper supplementation...