Waleh N S, Stocker B A
J Bacteriol. 1979 Feb;137(2):830-8. doi: 10.1128/jb.137.2.830-838.1979.
The ability of plasmid R46 to reduce the lethal but enhance the mutagenic effect of ultraviolet (UV) irradiation was tested in sets of Escherichia coli K-12 derivatives, wild type or with different mutations affecting DNA repair capacity, but otherwise isogenic. UV protection and enhancement of UV mutagenic effect were obtained in uvrA6, uvrB5, uvrD3, and recF143 hosts, but not in a recA56 strain. The plasmid gave some UV protection in two lexA1 and two lexA101 strains and in one lexA102 host, but produced no such effect in another lexA102 host. The plasmid restored UV mutagenic effect in a lexB30 strain, the yield of induced mutants per survivor of irradiation (10 J/m2) being about the same for the lexB30(R46) and lex+(R46) strains; by contrast the plasmid, though it reduced the UV sensitivity of the lexB30 strain, did not make it as UV-resistant as the lex+ R-strain.
在一组大肠杆菌K-12衍生物中测试了质粒R46降低紫外线(UV)照射致死效应但增强其诱变效应的能力,这些衍生物为野生型或带有影响DNA修复能力的不同突变,但在其他方面是同基因的。在uvrA6、uvrB5、uvrD3和recF143宿主中获得了紫外线防护和紫外线诱变效应增强,但在recA56菌株中未获得。该质粒在两个lexA1和两个lexA101菌株以及一个lexA102宿主中提供了一定的紫外线防护,但在另一个lexA102宿主中未产生这种效果。该质粒在lexB30菌株中恢复了紫外线诱变效应,lexB30(R46)和lex+(R46)菌株经照射(10 J/m2)后每个存活者诱导突变体的产量大致相同;相比之下,该质粒虽然降低了lexB30菌株的紫外线敏感性,但并未使其具有与lex+ R菌株一样的抗紫外线能力。