Bresler S E, Verbenko V N, Kalinin V L
Genetika. 1985 Mar;21(3):384-90.
The frequencies of spontaneous mutations (reversions his-4----His+ and forward mutations to rifampicin-, nalidixic acid- or valine-resistance) in radiation-resistant mutants Gamr444 and Gamr445 are much lower than in the wild-type strain AB1157. His+ revertants and rifampicin-resistant mutants Rifr are induced by low doses of gamma-rays more efficiently than in the wild-type. Low doses of UV light only enhanced mutagenic activity in Gamr strains for induction of His+ reversions but not for Rifr mutations. For the wild-type strain the frequencies of His+ and Rifr mutations increase proportionally to the square of dose both of UV light and gamma-rays. For the most radioresistant Gamr444 mutant the frequencies of UV- and gamma-rays-induced Rifr mutations and of gamma-rays-induced reversions increase linearly with the dose. Possible reasons for these anomalies of radiation-induced mutagenesis in Gamr mutants are discussed.
耐辐射突变体Gamr444和Gamr445中自发突变（组氨酸-4----组氨酸+回复突变以及向利福平抗性、萘啶酸抗性或缬氨酸抗性的正向突变）的频率远低于野生型菌株AB1157。低剂量γ射线比野生型更有效地诱导组氨酸+回复突变体和利福平抗性突变体Rifr。低剂量紫外线仅增强了Gamr菌株中诱导组氨酸+回复突变的诱变活性，而对Rifr突变则没有增强作用。对于野生型菌株，紫外线和γ射线诱导的组氨酸+和Rifr突变频率均与剂量的平方成正比。对于最耐辐射的Gamr444突变体，紫外线和γ射线诱导的Rifr突变频率以及γ射线诱导的回复突变频率随剂量呈线性增加。文中讨论了Gamr突变体中辐射诱导诱变这些异常现象的可能原因。
