Antibiotic-resistant mutants of γ-irradiated vibrios

It was demonstrated that a nutrition medium has a protective effect against γ-radiation-induced lethal damages to vibrios. The values of D0 and LD90 were 3 times higher for vibrios irradiated in a nutrition medium than in a physiological solution. There was a small shoulder in the survival curve under both irradiation conditions. Exposure of vibrios to γ-quanta induced mutations resistant to streptomycin, their frequency increasing exponentially with radiation dose. The frequency of spontaneous mutations resistant to streptomycin was (5.85+-1.90)x10-8. Mutations resistant to chloramphenicol did not occur spontaneously and were not induced by γ-radiation. A spontaneous streptomycin-resistant mutant did not differ in radiosensitivity from the parent strain: n=1.54 and 1.46, D0=12.2 and 12.1 Gy and LD90=32.7 and 33.9 Gy respectively