RESISTANCE AND CROSS-RESISTANCE OF ESCHERICHIA COLI MUTANTS TO ANTICANCER AGENTS. 1-METHYL-3-NITRO-1-NITROSOGUANIDINE

Abstract

Two sequential-step mutants.of Escherichia coli strain S, resistant to l-methyl-3-nitro-l-nitroso-guanidine, were tested for their resistance to other radiomimetic compounds and to UV light. S/Ng 1, the first-step resistant mutant, was significantly resistant to l-chloroethyl-3-nitro-l-nitrosoguanidine, l-chloropropyl-3-nitro-l-nitrosoguanidine, nitrogen mustard, nitromin, azaserine, and Mitomycin C. It was as sensitive as the parent strain S to 6-diazo-5-oxo-L-norleucine and penicillin. The second-step resistant mutant (S/Ng 2) was significantly more resistant than S/Ng 1 to 1-methyl-, 1-chloroethyl-, and l-chloropropyl-3-nitro-l-nitrosoguanidine. It was slightly (2-fold) more resistant to Mitomycin C, but much more sensitive to nitrogen mustard and nitromin, and slightly more sensitive to azaserine than was S/Ng 1. It was as sensitive as S and S/Ng 1 to 6-diazo-5-oxonorleucine and penicillin. S/Ng 1 and S/Ng 2 responded similarly to UV light; both were 10 times more resistant than S.