Enhancement of deoxyribonucleic acid polymerase I-directed repair synthesis in toluene-treated Escherichia coli after growth in the presence of low levels of N-methyl-N'-nitro-N-nitrosoguanidine.

Deoxyribonucleic acid polymerase I-directed repair synthesis can be selectively measured in toluene-treated Escherichia coli cells exposed to alkylating chemicals such as N-methyl-N'-nitro-N-nitrosoguanidine. Prior growth of the cells in the presence of a low dose of N-methyl-N'-nitro-N-nitrosoguanidine results in an enhanced deoxyribonucleic acid polymerase I-directed repair synthesis and an increase in single-strand breaks.