title: [Differences in the mutagenic effectiveness of N-nitrosomethyl- and N-nitrosoethylurea acting on bacterial DNA in vivo].
abstract: Chemically induced lethals and reversion frequencies of two mutants of Salmonella typhimurium LT-2 1530 and 1532 were examined. Prototrophic mutants to histidine independence occurred by two different mechanisms and were induced by nitrous acid, hydroxylamine, N-nitrosomethylurea (NMU), N-nitrosoethylurea (NEU) and N, N, nitrosodimethylurea (NDMU). The ability of the mutants to revert was affected by the chemical structure (in the row of N-nitrosoalkylurea - by alkyl group) of the mutagen. NEU is found to induce in bacterial DNA only base pair substitutions; NMU and NDMU - deletions and base pair substitutions. An original model of deletion mechanism with Goldwait endonuclease II participation is proposed.
mesh_terms: D001483:Base Sequence / Q000187:drug effects; D004269:DNA, Bacterial; D005038:Ethylnitrosourea / Q000494:pharmacology*; D008770:Methylnitrosourea / Q000494:pharmacology*; D009153:Mutagens / Q000494:pharmacology*; D009607:Nitrosourea Compounds / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects*
chemical_list: D004269:DNA, Bacterial; D009153:Mutagens; D009607:Nitrosourea Compounds; D008770:Methylnitrosourea; D005038:Ethylnitrosourea
vernacular_title: Razlichiia v mutagennoĭ éffektivnosti N-nitrozometil- i N-nitrozoétilmocheviny pri deĭstvii na bakterial'nuiu DNK in vivo