Mutation enhancing effect of o-vanillin in the lacZ gene of Escherichia coli: characterization of mutational spectrum.
The enhancing effect of o-vanillin (2-hydroxy-3-methoxybenz-aldehyde) on mutations induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) was characterized with mutational specificity. The mutational spectrum of MNNG-induced mutations in the presence of o-vanillin was compared with that in the absence of o-vanillin by means of a series of mutant lacZ genes in E. coli that can detect each of the six types of base substitutions and five kinds of frameshift events. In the absence of o-vanillin, the mutational spectrum induced by MNNG consisted mainly of G.C-->A.T transitions and, to a lesser extent, -1(G.C) frameshift mutations. By adding o-vanillin at 75 micrograms/plate, a marked enhancement was observed in two transitions, G.C-->A.T and A.T-->G.C, and in two frameshift mutations, +1(G.C) and -1(G.C). Only a small change was observed in the -2(C.G-G.C) fraction. Regarding the MNNG-induced frameshifts at the A.T base pair, the +1(A.T) frameshift was much more enhanced by o-vanillin than the -1(A.T) frameshift.
Watanabe
K
K
Institute of Environmental Toxicology, Tokyo, Japan.
Ohta
T
T
D001547:Benzaldehydes / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004926:Escherichia coli / Q000235:genetics; D016368:Frameshift Mutation / Q000187:drug effects; D005798:Genes, Bacterial / Q000187:drug effects; D008769:Methylnitronitrosoguanidine / Q000008:administration & dosage*; D009152:Mutagenicity Tests; D009153:Mutagens; D017354:Point Mutation / Q000187:drug effects; D001616:beta-Galactosidase / Q000235:genetics*
D001547:Benzaldehydes; D009153:Mutagens; C060843:2-vanillin; D008769:Methylnitronitrosoguanidine; D001616:beta-Galactosidase