title: Adaptive response of Micrococcus luteus to alkylating chemicals.
abstract: Wild type M. luteus cells have been adapted by a step-wise treatment with sub-lethal concentrations of MNNG. The adapted cells exhibit 5.7 fold increased resistance to the killing effects of the mutagen and a simultaneous efficient removal of various base modifications present in cellular DNA. A protein extract prepared from adapted cells contains inducible repair functions which can reduce 80-90% of the alkylated DNA content of 06-MeG is effected by a transmethylase and there is no concomitant release of the modified base. However, N-3 MeG is released as a free modified base through the action of a DNA glycosylase. The release of N-3 MeA is unaffected by the induction treatment whereas that of N-7 methylpurine is slightly improved in the adapted cells.
mesh_terms: D000477:Alkylating Agents / Q000633:toxicity*; D004260:DNA Repair; D004269:DNA, Bacterial / Q000235:genetics; D004351:Drug Resistance; D007700:Kinetics; D008745:Methylation; D008769:Methylnitronitrosoguanidine / Q000633:toxicity*; D008770:Methylnitrosourea / Q000633:toxicity; D008837:Micrococcus / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development; D013329:Structure-Activity Relationship
chemical_list: D000477:Alkylating Agents; D004269:DNA, Bacterial; D008769:Methylnitronitrosoguanidine; D008770:Methylnitrosourea