title: Mutagenicity of nitrosocarbaryl and other methylating nitrosamides as related to uptake in Haemophilus influenzae.
abstract: Differences greater than 6,000-fold in the mutagenic potency of three nitrosamides that are methylating agents [N-methyl-N-nitrosourea (MNU), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-nitrosocarbaryl (NC)] could be accounted for in part by differences in their uptake into the Haemophilus influenzae cells. Uptake was roughly correlated with the octanol/water partition coefficient. The most potent mutagen, NC, was concentrated by the cells. The least potent, MNU, was essentially excluded from the bacteria. Uptake was a linear function of concentration, whereas induction of novobiocin-resistant mutations followed higher-order kinetics. The effective dose of chemical to the bacteria (number of molecules taken up) under conditions of mutagenesis could be calculated.
mesh_terms: D012721:Carbaryl / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006193:Haemophilus influenzae / Q000235:genetics* / Q000378:metabolism*; D008769:Methylnitronitrosoguanidine / Q000494:pharmacology*; D008770:Methylnitrosourea / Q000494:pharmacology*; D009152:Mutagenicity Tests; D009153:Mutagens; D009602:Nitrosamines / Q000494:pharmacology*; D009603:Nitroso Compounds / Q000378:metabolism; D009607:Nitrosourea Compounds / Q000494:pharmacology*
chemical_list: D009153:Mutagens; D009602:Nitrosamines; D009603:Nitroso Compounds; D009607:Nitrosourea Compounds; D008769:Methylnitronitrosoguanidine; D008770:Methylnitrosourea; C008649:nitrosocarbaryl; D012721:Carbaryl