Using a nonselective method, we have estimated the proportion of untargeted mutations in the lad gene of E. coli by transferring either irradiated or unirradiated F' pro lac plasmids from an excision deficient donor to an excision deficient pro lac deleted recipient that had been irradiated and allo
Analysis of the antimutagenic effect of cinnamaldehyde on chemically induced mutagenesis in Escherichia coli
β Scribed by Ohta, Toshihiro ;Watanabe, Kazuko ;Moriya, Masaaki ;Shirasu, Yasuhiko ;Kada, Tsuneo
- Publisher
- Springer
- Year
- 1983
- Tongue
- English
- Weight
- 754 KB
- Volume
- 192
- Category
- Article
- ISSN
- 0026-8925
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β¦ Synopsis
The antimutagenic effect of cinnamaldehyde on mutagenesis was investigated using ten kinds of chemical mutagen in Escherichia coli WP2s (uvr A-). In addition, the frequency of mutation induction by each mutagen in an SOS repair deficient (umuC-) strain was compared with that in a wild-type (umuC+) strain. Cinnamaldehyde greatly suppressed the umuC-dependent mutagenesis induced by 4-nitroquinoline 1-oxide (4-NQO), furylfuramide or captan. However, cinnamaldehyde was less effective against the umuC-independent mutagenesis by alkylating agents such as N-methyl-N'-nitro-N-nitrosoguanidine and ethylmethanesulfonate. On the other hand, no inhibitory effect of cinnamaldehyde was observed on prophage induction or tif-mediated filamentous growth. These results suggest that a cinnamaldehyde does not prevent the induction of the SOS functions. Despite the decrease in the number of revertants, a remarkable increase was observed in the survival of 4-NQO-treated WP2s cells after exposure to cinnamaldehyde. The reactivation of survival suggests the promotion of some DNA repair system by cinnamaldehyde. This enhancement of survival was also observed in uvr B, polA, recF or umuC mutants and less in lexA or recB, C mutants. However, it was not observed in recA mutants. Therefore, we assume that cinnamaldehyde may enhance an error-free recombinational repair system by acting on recA-enzyme activity.
π SIMILAR VOLUMES
The E. coli dnaQ gene encodes the epsilon subunit of DNA polymerase III (pol III) responsible for the proofreading activity of this polymerase. The mutD5 mutant of dnaQ chronically expresses the SOS response and exhibits a mutator phenotype. In this study we have constructed a set of E. coli AB1157