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Astrobiological Aspects of the Mutagenesis of Cosmic Radiation on Bacterial Spores

Moeller, Ralf and Reitz, Guenther and Berger, Thomas and Okayasu, Ryuichi and Nicholson, Wayne L. and Horneck, Gerda (2010) Astrobiological Aspects of the Mutagenesis of Cosmic Radiation on Bacterial Spores. Astrobiology, 10 (5), pp. 509-521. Mary Ann Liebert, Inc.. DOI: 10.1089/ast.2009.0429.

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Abstract

Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. In this study, spores of B. subtilis were used to study the effects of galactic cosmic radiation (GCR) on spore survival and induced mutagenesis. In interplanetary space, outside Earth's protective magnetic field, spore-containing rocks would be exposed to bombardment by high-energy charged particle radiation from galactic sources and from the Sun, which consists of photons (X-rays, γ rays), protons, electrons, and heavy, high-energy charged (HZE) particles. B. subtilis spores were irradiated with X-rays and accelerated heavy ions (helium, carbon, silicon and iron) in the linear energy transfer (LET) range of 2–200keV/μm. Spore survival and the rate of the induced mutations to Rifampicin-resistance depended on the LET of the applied species of ions and radiation, whereas the exposure to high-energy charged particles, for example, iron ions, led to a low level of spore survival and increased frequency of mutation to Rifampicin-resistance compared to low-energy charged particles and X-rays. Twenty-one Rifampicin-resistance mutant spores were isolated from X-ray and heavy ion–irradiated samples. Nucleotide sequencing located the Rifampicin-resistance mutations in the rpoB gene encoding the β-subunit of RNA polymerase. Most mutations were primarily found in Cluster I and were predicted to result in amino acid changes at residues Q469L, A478V, and H482P/Y. Four previously undescribed alleles in B. subtilis rpoB were isolated: L467P, R484P, and A488P in Cluster I and H507R in the spacer between Clusters I and II. The spectrum of Rifampicin-resistance mutations arising from spores exposed to components of GCR is distinctly different from those of spores exposed to simulated space vacuum and martian conditions.

Document Type:Article
Title:Astrobiological Aspects of the Mutagenesis of Cosmic Radiation on Bacterial Spores
Authors:
AuthorsInstitution or Email of Authors
Moeller, Ralf UNSPECIFIED
Reitz, Guenther UNSPECIFIED
Berger, Thomas UNSPECIFIED
Okayasu, Ryuichi National Institute of Radiological Sciences (NIRS), Research Center for Charged Particle Therapy, Heavy-Ion Radiobiology Research Group, Chiba-shi, Japan.
Nicholson, Wayne L. University of Florida, Department of Microbiology and Cell Science, Space Life Sciences Laboratory, Kennedy Space Center, Florida, USA.
Horneck, Gerda UNSPECIFIED
Date:2010
Journal or Publication Title:Astrobiology
Refereed publication:Yes
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:10
DOI:10.1089/ast.2009.0429
Page Range:pp. 509-521
Publisher:Mary Ann Liebert, Inc.
Status:Published
Keywords:Bacillus, Spores, High-energy charged particle bombardment, Lithopanspermia
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W FR - Forschung unter Weltraumbedingungen (old)
DLR - Research area:Space
DLR - Program:W FR - Forschung unter Weltraumbedingungen
DLR - Research theme (Project):W - Vorhaben Strahlenbiologie (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Aerospace Medicine > Radiation Biology
Deposited By: Kerstin Kopp
Deposited On:16 Jul 2010 09:21
Last Modified:20 Mar 2013 19:42

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