DAMAGE AND MUTAGENESIS OF ESCHERICHIA-COLI AND BACTERIOPHAGE-LAMBDA INDUCED BY OXATHIOLANE AND AZIRIDINYL STEROIDS

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 mor e 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 uvr A 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 le sions. An enhanced level of mutagenesis was observed when steroid-trea ted 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 w ild-type bacteria. Moreover, the oxathiolane steroid treatment of lamb da cI857-E. coli lysogen resulted in prophage induction in nutrient br oth 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.