title: Mutagenesis by nitrosoguanidine, ethyl methanesulfonate, and mutator gene mutH in continuous cultures of Escherichia coli.
abstract: Induction of T5-R mutations by alkylating agents N-methyl-N'-nitro-N-nitrosoguanidine (NTG) and ethyl methanesulfonate (EMS) was examined in glucose limited chemostat cultures of non-mutator and mutator (mutH) bacteria. In agreement with the proposal that NTG mutagenizes DNA at the replication fork, this mutagen (6.8 X 10-minus 6 M) showed replication-dependent mutagenesis in continuous culture. EMS (5-10-minus M)) induced mutagenesis could not be correlated with growth rate, which probably means that induction of mutagenic lesions (promutations) by this mutagen does not involve replicating genes. A large synergic response was found for the mutH gene in combination with NTG, supporting the hypothesis that the mutH gene product acts during DNA replication.
mesh_terms: D001431:Bacteriological Techniques; D004261:DNA Replication; D004926:Escherichia coli / Q000378:metabolism; D005020:Ethyl Methanesulfonate / Q000494:pharmacology*; D005809:Genes, Regulator; D005827:Genetics, Microbial; D008698:Mesylates / Q000494:pharmacology*; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D009153:Mutagens; D009154:Mutation / Q000187:drug effects; D009604:Nitrosoguanidines / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D008698:Mesylates; D009153:Mutagens; D009604:Nitrosoguanidines; D008769:Methylnitronitrosoguanidine; D005020:Ethyl Methanesulfonate