380

58 Sasaki, Y.F., H. Tezuka 1, M. Inoue, A. Uchida, M. Moriya and Y. Shirasu, Institute of Environ- mental Toxicology, Kodaira, Tokyo, and 1Na- tional Institute of Genetics, Mishima, Shizuoka (Japan)

Heritable translocation test on trimethyiphosphate in C3H mice

We reported at the last EMS (Syuzenji, 1982) that heritable translocations were induced by tri- methylphosphate (TMP) in C3H male mice at the stage of late spermatids. Heritable translocation tests were further carried out to investigate the dose-dependent effect of TMP.

Heritable translocation tests were performed in C3H male mice that received a single intraperi- toneal injection of TMP at a dose of 1000 or 1500 mg / kg at the post-meiotic sensitive stage of late spermatids. Inducibility of heritable translocations was assayed by fertility diagnosis and cytogenetic analysis of chromosomes of F 1 male mice. In this study, increases in the frequency of translocation carrier mice were detected at both 1000 mg/kg (15 of 284 F 1, 5.3%) and 1500 mg/kg (29 of 203 F~, 14.3%).

These results indicate that heritable transloca- tions were induced by TMP with clear dose de- pendency in male mice at the stage of late spermatids.

59 Sawada, M., T. Sofuni and M. Ishidate Jr., Na- tional Institute of Hygienic Sciences, Tokyo (Japan)

Cytogenetic effects of l , l-dichioroethylene in mammalian cells (II)

1,1-Dichloroethylene (DCE) was examined for its ability to induce chromosome aberrations and sister-chromatid exchanges (SCEs) in cultured Chinese hamster cells (CHL). When the rat micro- somal fraction ($9) was added at a relatively higher concentration, 1,1-DCE showed a significant in- crease of chromosome aberrations, and a weakly positive response in the SCE assay.

The incidence of chromosome aberrations in- duced by 1,1-DCE decreased on addition of glutathione (reduced form) or metyrapone. Two possible intermediate metabolites of 1,1-DCE in vivo, chloroacetyl chloride and chloroacetic acid, did not produce chromosome aberrations or SCEs. These findings agree with the hypothesis that the epoxide formed from 1,1-DCE by cytochrome P450, is mutagenic.

Furthermore, we carried out the micronucleus test in mice both by single and 4 repeated adminis- trations (1-day interval), but no positive result was obtained.

60 Shimoi, K., Y. Takagaki, Y. Nakamura, T. Noro, S. Fukushima, I. Tomita and T. Kada i, Shizuoka College of Pharmaceutical Sciences, Shizuoka, and 1 National Institute of Genetics, Mishima (Japan)

Antimutagenic effects of the crude extracts of plant and tannic acid on the mutagenesis induced by UV or chemicals

The antimutagenic activities of the crude ex- tracts of 150 kinds of plants were tested using E. coli B / r WP2. Methanol or ethylacetate extracts of Liquidambar forrnosana Hance (leaf), Sophora angustifolia Sieb et Zucc (rout), Fraxinus japonica Blume (bark), Terminalia chebuba Retz (fruit), Di- ospyros kaki Thunb (leaf) showed antimutagenic effects on UV-induced mutagenesis. Tannic acid was also tested. This suppressed mutagenesis in- duced by UV or 4NQO, but not that induced by MNNG. In E. coli B / r WP2, uvrA-, however, tannic acid showed no antimutagenic effect on UV- or 4NQO-induced mutagenesis under the test conditions in which no cellular toxicity was ob- served. WP2, was more sensitive to tannic acid than WP2. Tannic acid showed no inhibition on the expression of Trp + phenotype and its anti- mutagenic effect was not seen after 30 min incuba- tion of the UV-irradiated cells.

The above results suggest that the antimuta- genic effect of tannic acid is closely correlated with DNA repair occurring immediately after the UV irradiation.