Bacillus subtilis mutants deficient in the adaptive response to simple alkylating agents.
AUTOR(ES)
Morohoshi, F
RESUMO
Three mutant strains exhibiting hyper-sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine, but not to methyl methanesulfonate, were selected by a replica method from mutagenized spores of Bacillus subtilis. All three were totally deficient in the adaptive response to N-methyl-N'-nitro-N-nitrosoguanidine with regard to both lethality and mutagenesis. The activity to destroy O6-methylguanine residues in the methylated DNA was not elevated in the mutant cells by the pretreatment with sublethal concentrations of N-methyl-N'-nitro-N-nitrosoguanidine. This deficiency corresponded to the persistence of O6-methylguanine residues in the DNA of both control and pretreated mutant cells challenged with the drug. The lethal and mutagenic sensitivity of the mutant strains were observed only for methyl- or ethyl-nitroso compounds that are thought to be active as inducers and are also active in O-alkylation. Except for the insensitivity to methyl methanesulfonate, the phenotypes of these mutants look very similar to those of ada mutants isolated previously in Escherichia coli.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=214972Documentos Relacionados
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