辐射诱发缺色氨酸型大肠杆菌致死和致突变试验

RADIATION-INDUCED MUTAGENICITY AND LETHALITY IN TRYPTOPHAN-REQUIRING AUXOTROPHS OF ESCHERICHIA COLI

本文研究了X线和^(60)Coγ线在3种不同色氨酸营养缺陷型大肠杆菌中的致死和致突变效应。此三株菌为wP_2、wP_2A和Cm 891,均为硷基置换型。Cm 891具有R因子显示了对射线致突变有较高的敏感性。从实验中得到以下结果:(1)使用体外致突变试验确认电离辐射是一种致突变因子。(2)射线对三种菌的致死和较突变效应的敏感程度Cm 891>wP_2A>wP_2。(3)γ射线剂量率对三株菌的致死和致突变影响大剂量率强于小剂量率。(4)小剂量率γ射线对Cm 891的致死和致突效应与X射线相接近,但在wP_2和wP_2A则γ射线强于X射线。

Mutation and killing caused by X-ray radiation and ^(60)Co γ-rayradiation were studied in three different tryptophan-requiring auxotrophs (wp2,Wp2A, Cm 891) of Escherichia coli. These testers are sensitive to base pair substitu-tion mutagens. Cm891 carries a R-factor and is more sensitive than wp2 and wp2Ato radiation-induced mutation and lethality. The results of our study show that (1)ionizing radiation was mutagenic to E. coli, (2) the order of mutagenic sensitivityamong three strains to ionizing radiation was Cm 891>wp2A>wp2, (3) the dose rateof γ-ray influence mutagenicity and lethalty of E. coli strain, (4)the toxicity andmutagenicity of γ-ray were similar to X-ray when Cm891 was tested, however,γ-ray was more toxic and mutagenic than X-ray to wp2A ang wp2.