Some bacteria can adapt to radiation stress. With their short generation time, they are ideal subjects for studies of the cell protection systems and genetic controls of variability that enable resistance and survival. There is a general decrease in the number and variety of bacteria present in radiation contaminated soil. Cellulose fermenting, nitrifying and sulphate reducing bacteria show drastically reduced levels. While Bacillus cereus is the dominant heterotrophic bacterium, the facultative methylotrophic bacteria such as Methylobacterium extorquens and Methylobacterium mesophilicum are represented equally in contaminated and control soil samples. The strains of Methylobacterium and Bacillus isolated from the polluted area show high levels of superoxide dismutase activity as compared with other heterotrophic bacteria. These bacteria are highly resistant to hydrogen peroxide, and ultra-violet light has only a limited mutagenic effect. Anti-oxidant enzymes appear to protect cells from radiation damage and an enhanced capacity to repair DNA may also be involved. Information collected from these organisms will be transferred to the treatment of humans and animals suffering from radiation poisoning in the future.
Investigation of the effect of prolonged nuclear radiation on the aboriginal bacterial populations in the zone of the Chernobyl atomic power station catastrophe
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8 June 2021