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Elucidating the Molecular Basis and Regulation of Chromium(VI) Reduction by Shewanella oneidensis MR-1 and Resistance to Metal Toxicity Using Integrated Biochemical, Genomic, and Proteomic Approaches

Conference ·
OSTI ID:895560
The mediation of metal reduction by microorganisms has been investigated intensively from physiological and biochemical perspectives; however, little is known about the genetic basis and regulatory mechanisms underlying the ability of certain bacteria to transform or immobilize a wide array of heavy metals contaminating DOE field sites. Chromium(VI), for example, is one of several risk-driving contaminants at DOE sites and has been targeted by the DOE for bioremediation research. The bacterium Shewanella oneidensis MR-1 can potentially be used to immobilize chromium, a toxic and mutagenic metal, by reducing soluble Cr(VI) to the insoluble and less bioavailable form of Cr(III), thus facilitating its removal from contained-storage and natural sites. The overall goal of this study is to integrate targeted biochemical and proteomic analyses with genome-wide gene expression profiling to examine the molecular basis and regulation of chromium(VI) reduction by Shewanella oneidensis MR-1. Towards this goal, we will (1) isolate and identify the terminal chromium(VI) reductase and the gene(s) encoding this activity using whole-genome sequence information for MR-1 and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in conjunction with conventional protein purification and characterization techniques; (2) verify the function of the gene(s) encoding the terminal Cr(VI) reductase and compare whole transcriptome data with whole proteome data in order to understand the regulation of chromium reduction; and (3) investigate the molecular stress response and adaptation of S. oneidensis to toxic levels of soluble Cr(VI) and other heavy metals. This research will provide important information on the functional components and regulatory mechanisms of microbial metal reduction, which should prove valuable in developing effective assessment strategies for in situ bioremediation and genetically engineering desired bacteria for enhanced bioremediation.
Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN; University of Tennessee, Knoxville, TN
Sponsoring Organization:
USDOE - Office of Science (SC)
OSTI ID:
895560
Report Number(s):
CONF-NABIR2004-46
Country of Publication:
United States
Language:
English