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A Major Role for Non-Enzymatic Antioxidant Processes in the Radioresistance of Halobacterium salinarum



M Miral Dizdar, Pawel Jaruga, Courtney K. Robinson, Kim Webb, Amardeep Kaur, Nitin S. Baliga, Allen Place, Jocelyne DiRuggiero


Oxidative stress occurs when the generation of reactive oxygen species (ROS) exceeds the capacity of the cell’s endogenous systems to neutralize them. We analyzed the oxidative stress responses and cellular damage of the archaeon Halobacterium salinarum exposed to ionizing radiation (IR) and to chemical oxidants. We found that the damage caused by -irradiation was mechanistically different than that produced by hydrogen peroxide or by the superoxide-generating redox-cycling drug paraquat. ROS scavenging enzymes were essential for resistance to chemical oxidants, yet those enzymes were not necessary for H. salinarum resistance to IR. We showed that protein-free cell extracts from H. salinarum provided a high level of protection for protein activity against IR, in vitro, but did not protect DNA significantly. When compared with cell extracts of radiation sensitive bacteria, H. salinarum extracts were enriched in manganese, amino acids, and peptides supporting an essential role in ROS scavenging for those small molecules, in vivo. The data presented here contribute novel findings on the critical role played by non-enzymatic antioxidant processes in the resistance of H. salinarum to IR.
Journal of Bacteriology


DNA damage, DNA repair, GC/MS, Halobacterium salinarum, ionizing radiation, radioresistance


, M. , Jaruga, P. , Robinson, C. , Webb, K. , Kaur, A. , Baliga, N. , Place, A. and DiRuggiero, J. (2011), A Major Role for Non-Enzymatic Antioxidant Processes in the Radioresistance of Halobacterium salinarum, Journal of Bacteriology, [online], (Accessed May 30, 2024)


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Created April 1, 2011, Updated November 10, 2018