title: Effect of metal ions on the adaptive response induced by N-methyl-N-nitrosourea in Escherichia coli.
abstract: Induction of the adaptive response was quantified by analysis of beta-galactosidase released after the treatment of Escherichia coli CHS26/pYM3 (ada'-lacZ') with N-methyl-N-nitrosourea (MNU). Of the 15 metal ions examined, only Cd++ and Hg++ inhibited induction of the adaptive response with neither severe suppression of cell growth nor inhibition of the induction of the SOS response by MNU. Mutagenicity of MNU was potentiated by the presence of these metal ions in an E. coli strain. These results suggest that the inhibition mechanism involves a specific interaction of Cd++ or Hg++ with O6-methyl-guanine-DNA methyltransferase.
authors.affiliation: Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takahashi
authors.forename: T
authors.initials: T
authors.lastname: Imaeda
authors.forename: Y
authors.initials: Y
authors.lastname: Kawazoe
mesh_terms: D002104:Cadmium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D003300:Copper / Q000494:pharmacology; D004269:DNA, Bacterial / Q000187:drug effects* / Q000528:radiation effects; D004357:Drug Synergism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D008628:Mercury / Q000494:pharmacology; D008670:Metals / Q000494:pharmacology*; D008770:Methylnitrosourea / Q000494:pharmacology*; D008780:Methyltransferases / Q000378:metabolism; D009154:Mutation; D019853:O(6)-Methylguanine-DNA Methyltransferase; D013014:SOS Response, Genetics / Q000187:drug effects / Q000528:radiation effects; D012834:Silver / Q000494:pharmacology; D014466:Ultraviolet Rays; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D004269:DNA, Bacterial; D008670:Metals; D002104:Cadmium; D003035:Cobalt; D012834:Silver; D008770:Methylnitrosourea; D003300:Copper; D008780:Methyltransferases; D019853:O(6)-Methylguanine-DNA Methyltransferase; D001616:beta-Galactosidase; D008628:Mercury