Filippov V D, Lotareva O V
Genetika. 1978 Aug;14(8):1303-9.
UV-light induces reversions to threonine-independence in BD170 Rec+ cells, and does not induce them in isogenic strain BD241 recF. Reversions to methionine-independence are induced in cells GSY1028 recB, and are not in isogenic strain GSY1025 recA. It is possible to construct, with the use of transformation, a viable strain carrying mutations recF and su, the latter imparts threinine-independence to cells. Hence, the absence of UV-induced reversions in recF (and probably in recA) cells can not be explained by the lethal effect of joining, in one genome, two mutations each of which decreases a viability of bacteria. Formation of UV-induced forward mutations which provide additional growth requirements to bacteria is not disturbed in strains recA and recF. Experimental data allow to conclude that UV-induced mutagenesis is not a function of any of two known mechanisms of recombination which function in Bacillus subtilis cells.
紫外线可诱导BD170 Rec⁺细胞回复为苏氨酸非依赖型，而在同基因菌株BD241 recF中则不会诱导这种回复。GSY1028 recB细胞可诱导回复为甲硫氨酸非依赖型，而在同基因菌株GSY1025 recA中则不会。通过转化可以构建出携带recF和su突变的活菌株，后者可使细胞对苏氨酸产生非依赖性。因此，recF（可能还有recA）细胞中不存在紫外线诱导的回复突变，不能用在一个基因组中同时存在两个降低细菌生存能力的突变所产生的致死效应来解释。在recA和recF菌株中，紫外线诱导的正向突变的形成并未受到干扰，这些正向突变为细菌提供了额外的生长需求。实验数据表明，紫外线诱导的诱变作用并非枯草芽孢杆菌细胞中两种已知重组机制中任何一种的功能。
