Mechanisms of Resistance to Ionizing Radiation in Extremophiles

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dc.contributor.advisorRobb, Frank T.en_US
dc.contributor.authorWebb, Kimberly Michelleen_US
dc.contributor.departmentMarine-Estuarine-Environmental Sciencesen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2012-10-11T05:56:02Z
dc.date.available2012-10-11T05:56:02Z
dc.date.issued2012en_US
dc.description.abstractExtremophiles display an astonishing array of adaptations to harsh environmental conditions. We analyzed the mechanisms of ionizing radiation resistance from a diverse group of extremophilic archaea and bacteria. In Halobacterium salinarum IR resistance is conferred by antioxidant Mn2+-complexes, and protein-free cell extracts (ultrafiltrates, UFs) of super-resistant (IR+) isolates of H. salinarum had increased concentrations of Mn, PO4 and amino acids compared to the founder strain. Proteomic analysis determined that IR+ isolates with increased Mn had elevated protein expression for central carbon metabolism, suggesting a Mn-stimulated metabolic route to increased IR resistance. We examined the role of mannosylglycerate, di-myo-inositol phosphate, and trehalose in the IR resistance of various thermophiles; aerobic thermophiles had UFs which were radioprotective of enzyme activity under aerobic conditions, which is attributed to Mn, PO4 and trehalose accumulation. In contrast, anaerobic thermophile UFs did not contain significant amounts of Mn, and were radioprotective only under anaerobic conditions; we conclude the anaerobic environment confers their IR resistance.en_US
dc.identifier.urihttp://hdl.handle.net/1903/13190
dc.subject.pqcontrolledMolecular biologyen_US
dc.subject.pquncontrolledHalophileen_US
dc.subject.pquncontrolledIonizing Radiationen_US
dc.subject.pquncontrolledManganeseen_US
dc.subject.pquncontrolledThermophileen_US
dc.titleMechanisms of Resistance to Ionizing Radiation in Extremophilesen_US
dc.typeThesisen_US

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