title: Enhancement by cysteamine of N-methyl-N-nitrosourea mutagenesis in E. coli.
abstract: Cysteamine (MEA) is comutagenic to methylnitrosourea (MNU) in E. coli AB 1157 but not in the nonadaptable mutant derivative ada-6 of that strain. The comutagenic action of MEA was eliminated by cysteine at low concentrations, which also lowered mutation frequencies in AB1157 but not in ada-6. In model experiments it was shown that cysteine counteracted the inhibition by MEA of beta-galactosidase induction in both bacterium strains. The comutagenic action of MEA is interpreted as being due to an inhibition of induction of methyltransferase during treatment with MNU.
authors.forename: M
authors.initials: M
authors.lastname: Näslund
authors.forename: A
authors.initials: A
authors.lastname: Kolman
authors.forename: L
authors.initials: L
authors.lastname: Ehrenberg
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D003543:Cysteamine / Q000494:pharmacology*; D003864:Depression, Chemical; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D004790:Enzyme Induction / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects; D008770:Methylnitrosourea / Q000494:pharmacology*; D008780:Methyltransferases / Q000037:antagonists & inhibitors; D001616:beta-Galactosidase / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D003543:Cysteamine; D008770:Methylnitrosourea; D008780:Methyltransferases; D001616:beta-Galactosidase