Moeller, Ralf and Reitz, Günther and Li, Zuofeng and Klein, Stuart and Nicholson, Wayne L. (2012) Multifactorial Resistance of Bacillus subtilis Spores to High-Energy Proton Radiation: Role of Spore Structural Components and the Homologous Recombination and Non-Homologous End Joining DNA Repair Pathways. Astrobiology, 12 (11), pp. 1069-1077. Mary Ann Liebert, Inc.. DOI: 10.1089/ast.2012.0890.
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The space environment contains high-energy charged particles (e.g., protons, neutrons, electrons, α-particles, heavy ions) emitted by the Sun and galactic sources or trapped in the radiation belts. Protons constitute the majority (87%) of high-energy charged particles. Spores of Bacillus species are one of the model systems used for astro- and radiobiological studies. In this study, spores of different Bacillus subtilis strains were used to study the effects of high energetic proton irradiation on spore survival. Spores of the wild-type B. subtilis strain [mutants deficient in the homologous recombination (HR) and non-homologous end joining (NHEJ) DNA repair pathways and mutants deficient in various spore structural components such as dipicolinic acid (DPA), α/β type small, acidsoluble spore protein (SASP) formation, spore coats, pigmentation, or spore core water content] were irradiated as air-dried multilayers on spacecraft-qualified aluminum coupons with 218 MeV protons [with a linear energy transfer (LET) of 0.4 keV/μm] to various final doses up to 2500 Gy. Spores deficient in NHEJ- and HR-mediated DNA repair were significantly more sensitive to proton radiation than wild-type spores, indicating that both HR and NHEJ DNA repair pathways are needed for spore survival. Spores lacking DPA, α/β-type SASP, or with increased core water content were also significantly more sensitive to proton radiation, whereas the resistance of spores lacking pigmentation or spore coats was essentially identical to that of the wild-type spores. Our results indicate that α/β-type SASP, core water content, and DPA play an important role in spore resistance to high-energy proton irradiation, suggesting their essential function as radioprotectants of the spore interior.
|Title:||Multifactorial Resistance of Bacillus subtilis Spores to High-Energy Proton Radiation: Role of Spore Structural Components and the Homologous Recombination and Non-Homologous End Joining DNA Repair Pathways|
|Journal or Publication Title:||Astrobiology|
|In ISI Web of Science:||Yes|
|Page Range:||pp. 1069-1077|
|Publisher:||Mary Ann Liebert, Inc.|
|Keywords:||Bacillus, Spores, DNA repair, Protection, High-energy proton radiation|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Space|
|HGF - Program Themes:||Research under Space Conditions|
|DLR - Research area:||Raumfahrt|
|DLR - Program:||R FR - Forschung unter Weltraumbedingungen|
|DLR - Research theme (Project):||R - Vorhaben Strahlenbiologie|
|Institutes and Institutions:||Institute of Aerospace Medicine > Radiation Biology|
|Deposited By:||Kerstin Kopp|
|Deposited On:||12 Nov 2012 09:15|
|Last Modified:||20 Mar 2013 19:45|
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