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NTP non-carcinogens
92 threshold concentration between 0.01% and 0.025%, but not in the case of natural soap. The result supported our previous observations that AS and LAS can interrupt pregnancy of mice by killing fertilized eggs.
22 Jinno, H. l, T. Matsuda 2, H. Sekita 1, M. Ando 1 and M. Takeda 1, i Division of Environmental Chemistry, National Institute of Hygienic Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158 and 2 Water Examination Laboratory, Sapporo Water Works Bureau (Japan)
Mutagenic activity of diphenyl ether herbicides and their reactivity with chlorine in aqueous solution Diphenyl ether herbicides, chlornitrofen (CNP), chlormethoxynil (X-52) and bifenox were tested for mutagenic activity toward Salmonella typhimurium YG1021 and YG1026, which are more sensitive to nitroarenes than the conventional tester strains TA98 and TA100. Using tester strains TA98 and TA100, only X-52 was detected as a weak mutagen in strain TA100 without $9 mix. When YG1021 and YG1026 were used, however, not only X-52 but also CNP was found to possess mutagenic activity, yielding 70 revertants/~g and 15 revertants/#g in strain YG1026 without $9 mix, respectively. The reactivity of diphenyl ether herbicides with chlorine, which is used as a disinfectant in the treatment of drinking water, was examined in aqueous solution. Under the conditions employed in this study (herbicide: 0.2 rag/l, CI:: 100 mg/1, reaction time: 24 h, pH 5, 7 or 9), only X-52 reacted at pH 5 and decreased to 40% of the initial amount. The mutagenic activity of the reaction mixture was at least 5 times higher than that of X-52. The chlorination mixture was separated by HPLC and the mutagenic fraction was analyzed by G C / M S and NMR. The mutagenic chlorination product was identified as chloro-substituted X-52, 2,4-dichlorophenyl 2'-chloro-5'-methoxy4'-nitrophenyl ether. 23 Kabaya, K., M. Kobayashi, H. Inoue and K. Yoshikawa, Toxicology Laboratory, Life Science
Sector, Research Center, Mitsubishi Kasei Co., 1000, Kamoshida-cho, Midori-ku, Kanagawa-ken, Yokohama 227 (Japan)
Results of Drosophila wing spot test (SMART) with 23 N C I / N T P non-carcinogens The Drosophila SMART assay detects various types of carcinogens including those that require metabolic activation with a frequency of 92% (57/62) (Wtirgler and Vogel, 1985). However, only a few non-carcinogens have been tested in this assay. As stated by Shelby and Stasiewicz (1984), the scarce results for non-carcinogens in short-term tests (STTs) impeded the evaluation of the predictive value of STYs. Therefore, we performed the SMART assay with 23 non-carcinogens evaluated in carcinogenicity tests conducted by the NCI and the NTP (Tennant et al., 1987). mwh ÷/÷ fir J larvae, 48-72 h old, were fed on Drosophila Instant Medium hydrated with a solution or emulsion of the test chemical, until pupation. The criterion for positive response was a significant increase in the frequency of mwh large spots (>/3 cells) in flies recovered from subtoxic (70-90% survival) or toxic (30-70% survival) cultures over that in the control flies. The results revealed that, of the 23 chemicals tested, only 2,6-toluenediamine gave a positive response, the specificity (percentage of correctly identified non-carcinogens) being 96% (22/23)° This value is higher than those reported in 4 STYs for the corresponding chemicals, 86% (19/22) for SAL, 41% (9/22) for MOLY, 59% (13/22) for ABS and 36% (8/22) for SCE (Tennant et al., 1987). These results allow us to conclude that the SMART assay gives the lowest number of false-positive responses.
24 Kato, T., K. Kikugawa, M. Asanoma I and Y. Sakabe 1, Tokyo College of Pharmacy, 1432-1 Horinouchi, Hachioji, Tokyo 192-03 and i Nagoya City Health Research Institute, 1-11 Hagiyama-cho, Mizuho-ku, Nagoya 467 (Japan)
Occurrence of heterocyclic amine mutagens in oil of charred egg yolk (ranyu) The mutagenicity of oil of charred egg yolk (called ranyu in Japanese), which is commercially
22 Jinno, H. l, T. Matsuda 2, H. Sekita 1, M. Ando 1 and M. Takeda 1, i Division of Environmental Chemistry, National Institute of Hygienic Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158 and 2 Water Examination Laboratory, Sapporo Water Works Bureau (Japan)
Mutagenic activity of diphenyl ether herbicides and their reactivity with chlorine in aqueous solution Diphenyl ether herbicides, chlornitrofen (CNP), chlormethoxynil (X-52) and bifenox were tested for mutagenic activity toward Salmonella typhimurium YG1021 and YG1026, which are more sensitive to nitroarenes than the conventional tester strains TA98 and TA100. Using tester strains TA98 and TA100, only X-52 was detected as a weak mutagen in strain TA100 without $9 mix. When YG1021 and YG1026 were used, however, not only X-52 but also CNP was found to possess mutagenic activity, yielding 70 revertants/~g and 15 revertants/#g in strain YG1026 without $9 mix, respectively. The reactivity of diphenyl ether herbicides with chlorine, which is used as a disinfectant in the treatment of drinking water, was examined in aqueous solution. Under the conditions employed in this study (herbicide: 0.2 rag/l, CI:: 100 mg/1, reaction time: 24 h, pH 5, 7 or 9), only X-52 reacted at pH 5 and decreased to 40% of the initial amount. The mutagenic activity of the reaction mixture was at least 5 times higher than that of X-52. The chlorination mixture was separated by HPLC and the mutagenic fraction was analyzed by G C / M S and NMR. The mutagenic chlorination product was identified as chloro-substituted X-52, 2,4-dichlorophenyl 2'-chloro-5'-methoxy4'-nitrophenyl ether. 23 Kabaya, K., M. Kobayashi, H. Inoue and K. Yoshikawa, Toxicology Laboratory, Life Science
Sector, Research Center, Mitsubishi Kasei Co., 1000, Kamoshida-cho, Midori-ku, Kanagawa-ken, Yokohama 227 (Japan)
Results of Drosophila wing spot test (SMART) with 23 N C I / N T P non-carcinogens The Drosophila SMART assay detects various types of carcinogens including those that require metabolic activation with a frequency of 92% (57/62) (Wtirgler and Vogel, 1985). However, only a few non-carcinogens have been tested in this assay. As stated by Shelby and Stasiewicz (1984), the scarce results for non-carcinogens in short-term tests (STTs) impeded the evaluation of the predictive value of STYs. Therefore, we performed the SMART assay with 23 non-carcinogens evaluated in carcinogenicity tests conducted by the NCI and the NTP (Tennant et al., 1987). mwh ÷/÷ fir J larvae, 48-72 h old, were fed on Drosophila Instant Medium hydrated with a solution or emulsion of the test chemical, until pupation. The criterion for positive response was a significant increase in the frequency of mwh large spots (>/3 cells) in flies recovered from subtoxic (70-90% survival) or toxic (30-70% survival) cultures over that in the control flies. The results revealed that, of the 23 chemicals tested, only 2,6-toluenediamine gave a positive response, the specificity (percentage of correctly identified non-carcinogens) being 96% (22/23)° This value is higher than those reported in 4 STYs for the corresponding chemicals, 86% (19/22) for SAL, 41% (9/22) for MOLY, 59% (13/22) for ABS and 36% (8/22) for SCE (Tennant et al., 1987). These results allow us to conclude that the SMART assay gives the lowest number of false-positive responses.
24 Kato, T., K. Kikugawa, M. Asanoma I and Y. Sakabe 1, Tokyo College of Pharmacy, 1432-1 Horinouchi, Hachioji, Tokyo 192-03 and i Nagoya City Health Research Institute, 1-11 Hagiyama-cho, Mizuho-ku, Nagoya 467 (Japan)
Occurrence of heterocyclic amine mutagens in oil of charred egg yolk (ranyu) The mutagenicity of oil of charred egg yolk (called ranyu in Japanese), which is commercially