title: Exposure to low concentrations of mutagens alters the mutagenic and lethal effects of 4-nitroquinoline-N-oxide and mitomycin C in Escherichia coli.
abstract: Mitomycin C and 4-nitroquinoline-N-oxide are two mutagens which can induce the SOS DNA repair system in Escherichia coli. Growth of E. coli B/r strain WP2, or its uvrA- derivative, in very low concentrations of either mutagen led to the increased sensitization to the lethal and/or mutagenic effects of a subsequent challenge with the same mutagen. These phenomena were not observed in either the recA- or lexA- derivatives of the parent strain. Induction of the adaptive response repair pathway by prior cultivation in low concentrations of N-methyl-N'-nitro-N-nitrosoguanidine reduced both the mutagenic and lethal effects of a subsequent challenge with mitomycin C but not 4-nitroquinoline-N-oxide.
mesh_terms: D015112:4-Nitroquinoline-1-oxide / Q000633:toxicity*; D004260:DNA Repair / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology; D016685:Mitomycin; D008937:Mitomycins / Q000633:toxicity*; D009154:Mutation / Q000187:drug effects*; D009600:Nitroquinolines / Q000633:toxicity*
chemical_list: D008937:Mitomycins; D009600:Nitroquinolines; D008769:Methylnitronitrosoguanidine; D016685:Mitomycin; D015112:4-Nitroquinoline-1-oxide