Year: 2003
Type: dissertation
Abstract: The extremely radiation resistant vegetative bacterium Deinococcus radiodurans was isolated in 1956 from gamma-irradiated meat. Since then, it has been the subject of research aimed at understanding the genetic mechanisms underlying its resistance phenotype. In addition to being able to survive high doses of acute gamma radiation, the organism can grow under chronic gamma radiation and recover from a range of other DNA damaging conditions including exposure to desiccation, ultraviolet (UV) radiation and chemical genotoxic agents. This remarkable range of resistance has been attributed to efficient DNA repair processes capable of mending hundreds of single- and double-stranded DNA breaks without lethality or induced mutation. These characteristics were the impetus for sequencing the D. radiodurans genome, ongoing development for bioremediation, proteome and whole genome expression analyses. This thesis examines the relationships between radiation resistance, desiccation resistance, and thermotolerance in three novel D. radiodurans mutants (DR0070, DR0105, and DR2339). Mutants were tested for their ability to survive gamma radiation, desiccation, and elevated temperature. Results support that i) radiation resistance mechanisms responsible for survival following exposure to acute radiation are distinct from those needed for survival under chronic radiation, and ii) radiation resistance mechanisms responsible for survival under chronic radiation appear to be related to those involved with growth at elevated temperatures and desiccation resistance.
Source: KOPS (University of Konstanz)
Author: Matthias Hess
Language: Italian
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2104409683