Browsing by Author "Martinez, Robert J."
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Item Complete Genome Sequence of Rahnella aquatilis CIP 78.65(American Society of Microbiology, 2012) Martinez, Robert J.; Bruce, David; Detter, Chris; Goodwin, Lynne A.; Han, James; Han, Cliff S.; Held, Brittany; Land, Miriam L.; Mikhailova, Natalia; Nolan, Matt; Pennacchio, Len; Pitluck, Sam; Tapia, Roxanne; Woyke, Tanja; Sobeckya, Patricia A.; University of Alabama Tuscaloosa; United States Department of Energy (DOE); Los Alamos National Laboratory; Joint BioEnergy Institute - JBEI; Joint Genome Institute - JGI; Oak Ridge National LaboratoryRahnella aquatilis CIP 78.65 is a gammaproteobacterium isolated from a drinking water source in Lille, France. Here we report the complete genome sequence of Rahnella aquatilis CIP 78.65, the type strain of R. aquatilis.Item Complete Genome Sequence of Rahnella sp Strain Y9602, a Gammaproteobacterium Isolate from Metal- and Radionuclide-Contaminated Soil(American Society of Microbiology, 2012) Martinez, Robert J.; Bruce, David; Detter, Chris; Goodwin, Lynne A.; Han, James; Han, Cliff S.; Held, Brittany; Land, Miriam L.; Mikhailova, Natalia; Nolan, Matt; Pennacchio, Len; Pitluck, Sam; Tapia, Roxanne; Woyke, Tanja; Sobecky, Patricia A.; University of Alabama Tuscaloosa; United States Department of Energy (DOE); Los Alamos National Laboratory; Oak Ridge National LaboratoryRahnella sp. strain Y9602 is a gammaproteobacterium isolated from contaminated subsurface soils that is capable of promoting uranium phosphate mineralization as a result of constitutive phosphatase activity. Here we report the first complete genome sequence of an isolate belonging to the genus Rahnella.Item Microbial Community Analysis of a Coastal Salt Marsh Affected by the Deepwater Horizon Oil Spill(PLOS, 2012) Beazley, Melanie J.; Martinez, Robert J.; Rajan, Suja; Powell, Jessica; Piceno, Yvette M.; Tom, Lauren M.; Andersen, Gary L.; Hazen, Terry C.; Van Nostrand, Joy D.; Zhou, Jizhong; Mortazavi, Behzad; Sobecky, Patricia A.; University of Alabama Tuscaloosa; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of California Berkeley; University of Tennessee Knoxville; University of Oklahoma - Norman; Dauphin Island Sea LabCoastal salt marshes are highly sensitive wetland ecosystems that can sustain long-term impacts from anthropogenic events such as oil spills. In this study, we examined the microbial communities of a Gulf of Mexico coastal salt marsh during and after the influx of petroleum hydrocarbons following the Deepwater Horizon oil spill. Total hydrocarbon concentrations in salt marsh sediments were highest in June and July 2010 and decreased in September 2010. Coupled PhyloChip and GeoChip microarray analyses demonstrated that the microbial community structure and function of the extant salt marsh hydrocarbon-degrading microbial populations changed significantly during the study. The relative richness and abundance of phyla containing previously described hydrocarbon-degrading bacteria (Proteobacteria, Bacteroidetes, and Actinobacteria) increased in hydrocarbon-contaminated sediments and then decreased once hydrocarbons were below detection. Firmicutes, however, continued to increase in relative richness and abundance after hydrocarbon concentrations were below detection. Functional genes involved in hydrocarbon degradation were enriched in hydrocarbon-contaminated sediments then declined significantly (p<0.05) once hydrocarbon concentrations decreased. A greater decrease in hydrocarbon concentrations among marsh grass sediments compared to inlet sediments (lacking marsh grass) suggests that the marsh rhizosphere microbial communities could also be contributing to hydrocarbon degradation. The results of this study provide a comprehensive view of microbial community structural and functional dynamics within perturbed salt marsh ecosystems.Item Microbial Community Responses to Organophosphate Substrate Additions in Contaminated Subsurface Sediments(PLOS, 2014) Martinez, Robert J.; Wu, Cindy H.; Beazley, Melanie J.; Andersen, Gary L.; Conrad, Mark E.; Hazen, Terry C.; Taillefert, Martial; Sobecky, Patricia A.; University of Alabama Tuscaloosa; University of California Berkeley; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; University of Tennessee Knoxville; Georgia Institute of TechnologyBackground: Radionuclide-and heavy metal-contaminated subsurface sediments remain a legacy of Cold War nuclear weapons research and recent nuclear power plant failures. Within such contaminated sediments, remediation activities are necessary to mitigate groundwater contamination. A promising approach makes use of extant microbial communities capable of hydrolyzing organophosphate substrates to promote mineralization of soluble contaminants within deep subsurface environments. Methodology/Principal Findings: Uranium-contaminated sediments from the U. S. Department of Energy Oak Ridge Field Research Center (ORFRC) Area 2 site were used in slurry experiments to identify microbial communities involved in hydrolysis of 10 mM organophosphate amendments [i.e., glycerol-2-phosphate (G2P) or glycerol-3-phosphate (G3P)] in synthetic groundwater at pH 5.5 and pH 6.8. Following 36 day (G2P) and 20 day (G3P) amended treatments, maximum phosphate (PO43-) concentrations of 4.8 mM and 8.9 mM were measured, respectively. Use of the PhyloChip 16S rRNA microarray identified 2,120 archaeal and bacterial taxa representing 46 phyla, 66 classes, 110 orders, and 186 families among all treatments. Measures of archaeal and bacterial richness were lowest under G2P (pH 5.5) treatments and greatest with G3P (pH 6.8) treatments. Members of the phyla Crenarchaeota, Euryarchaeota, Bacteroidetes, and Proteobacteria demonstrated the greatest enrichment in response to organophosphate amendments and the OTUs that increased in relative abundance by 2-fold or greater accounted for 9%-50% and 3%-17% of total detected Archaea and Bacteria, respectively. Conclusions/Significance: This work provided a characterization of the distinct ORFRC subsurface microbial communities that contributed to increased concentrations of extracellular phosphate via hydrolysis of organophosphate substrate amendments. Within subsurface environments that are not ideal for reductive precipitation of uranium, strategies that harness microbial phosphate metabolism to promote uranium phosphate precipitation could offer an alternative approach for in situ sequestration.