Qadri S A, Ahmad M
Department of Biochemistry, A.M.U., Aligarh, India.
Mutat Res. 1994 Dec 1;311(2):199-208. doi: 10.1016/0027-5107(94)90177-5.
lambda-Escherichia coli complexes exhibited remarkable sensitivity to the treatment with test steroidal derivatives in the presence of Cu(II). The decline in plaque-forming units after steroid treatment was more pronounced in complexes with some of the radiation repair-defective mutants of E. coli K-12, i.e., recA, lexA and polA, as compared to uvrA and wild-type strains. The red gene of lambda phage and recA gene of E. coli seem to have a complementary effect on the steroid-induced lesions. An enhanced level of mutagenesis was observed when steroid-treated E. coli cells were transformed with steroid-treated pBR322 plasmid DNA. A remarkable degree of c mutation was also observed when steroid I-treated phage particles were allowed to adsorb on steroid-treated wild-type bacteria. Moreover, the oxathiolane steroid treatment of lambda cI857-E. coli lysogen resulted in prophage induction in nutrient broth even at 32 degrees C. Thus on the basis of these results, the role of SOS repair system in steroid-induced mutagenesis and repair of DNA lesions in E. coli and bacteriophage lambda has been suggested.
在铜（II）存在的情况下，λ-大肠杆菌复合物对测试甾体衍生物的处理表现出显著的敏感性。与uvrA和野生型菌株相比，甾体处理后噬菌斑形成单位的下降在与大肠杆菌K-12的一些辐射修复缺陷突变体（即recA、lexA和polA）形成的复合物中更为明显。λ噬菌体的red基因和大肠杆菌的recA基因似乎对甾体诱导的损伤有互补作用。当用甾体处理的pBR322质粒DNA转化经甾体处理的大肠杆菌细胞时，观察到诱变水平增强。当用甾体I处理的噬菌体颗粒吸附在经甾体处理的野生型细菌上时，也观察到显著程度的c突变。此外，对λcI857-大肠杆菌溶原菌进行氧杂硫杂环戊烷甾体处理，即使在32℃下的营养肉汤中也会导致原噬菌体诱导。因此，基于这些结果，有人提出了SOS修复系统在大肠杆菌和噬菌体λ中甾体诱导的诱变和DNA损伤修复中的作用。
