[Inactivation of isogenous strains of Bacillus subtilis and their mixtures by ionizing radiation]

Resistance to ionizing radiation of vegetative cells, spores and dehydrated cultures was studied with isogenous strains of Bacillus subtilis with defects in the repair systems. In vegetative cells of different classes of the recombination deficient mutants, DL90 was 31-35% of LD90 of the wild type cells. Differences in radiosensitivity of the vegetative cells were more pronounced cf. the spores and dehydrated cells: LD90 of rec- mutants was 55-88%; LD90 of uvr- mutants was 120% of LD90 of the parent bacterial cells.