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Mutagenic activity of cytidine analogs in cultured mammalian cells
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increased with age, which makes individual differences greater and greater in the male saline group. In the MMC group, this incidence increased with aging but decreased at the age of 80 weeks, in both males and females. In the MMC group, the 60-week-old males showed an incidence of 12%, almost twice that found in the 40-week-old males. The ratio of polychromatic erythrocytes to total erythrocytes, which indicates the hematopoietic function of the bone marrow, decreased with age up to 60 weeks in the male saline group but the ratio in the 80-week-old animals was similar to that in the 20-week-old animals. This ratio was little influenced by aging in the female saline group.
19 Kojima, M., The Biological Research Center for The Protection of Environment, Minakuchi, Koka, Shiga (Japan) Mutagenicity of anthocyanin-chromosome aberration test and mieronucleus test Recent work on the mutagenic activity of keracyanin, a kind of anthocyanin widely found as a plant pigment, has shown that keracyanin is nonmutagenic by the Salmonella/microsome activation system. We have studied the mutagenicities of keracyanin and cyanidin by the chromosome aberration test in vitro and by the micronucleus test in vivo. Keracyanin was obtained by the Mg + HC1 reduction of rutin and cyanidin was prepared by hydrolysis of keracyanin. Keracyanin was assayed by the chromosome aberration test with or without metabolic activation using Chinese hamster V79 cells, and by the micronucleus test using the bone marrow of BDF1 male mice. Cyanidin was assayed by the chromosome aberration test without metabolic activation. Incidence of cells with chromosome aberrations was elevated by 13-27% when V79 cells were exposed to keracyanin at a concentration of 2 mg/ml for 48 h without metabolic activation. Keracyanin and cyanidin were nonmutagenic in other test systems.
20 Kuroda, M., D. Yoshida and S. Mizusaki, Central Research Institute, The Japan Tabacco and Salt Public Corporation, Yokohama, Kanagawa 227 (Japan) Mutagenicity of pyrenequinone and perylenequinone on Salmonella typhimurium
Salmonella typhimurium TA97 is mutagenized by PAHs. We observed that the mutagenic response of TA97 to many PAHs was greater than that of TA98 or TA100. Pyrene and perylene were highly mutagenic to TA97. We consider that pyrene and perylene act through its metabolic conversion into quinones. Therefore, the mutagenicity of pyrenequinone and perylenequinone on TA97 was determined. Both 1,8-pyrenequinone and 3,10-perylenequinone were mutagenic without $9 mix. It was found that TA97 and the active-oxygen sensitive strains, TA102 and TA104 were sensitive to tert.-butylhydroperoxide. This suggests that the mutagenicity of these quinones is due to cellular enzyme-mediated production of active oxygen from the quinones. The mutagenicity of pyrenequinone on TA102 was increased by the addition of cell-free extract from TA97. This cell-free extract was more effective than those obtained from TA98, TA100, TA102 or TA104. No DT-diaphorase was detected in TA97.
21 Kuroda, Y., H. Hayatsu ~ and K. Negishi ~, Laboratory of Phenogenetics, Department of Ontogenetics, National Institute of Genetics, Mishima, Shizuoka 411, and ~Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700 (Japan) Mutagenic activity of cytidine analogs in cultured mammalian cells Among analogs of nucleic acid bases and nucleosides, 5-bromouridine and 2-aminopurine were mutagenic in microorganisms, fungi and mammalian cells. Recently, it has been found that
263
a reaction product of cytidine with hydrazine, N4-aminocytidine, was strongly mutagenic to bacteria and phage. In the present experiment, the mutagenic activity of N4-aminocytidine and N 4amino-2'-deoxycytidine in cultured Chinese hamster V79 cells was examined. The cytotoxic effects of both nucleoside analogs on V79 cells were determined by scoring the colony-forming activity of cells treated with these analogs for 3 h. The LDs0 value of N4-aminocytidine was 22 /tg/ml and that of N4-amino-2'-deoxycytidine was 50/~g/ml. Cells were treated with each of the analogs for 3 h, cultured in normal medium for 6 days, replated in fresh dishes, and cultured in 5 /tg/ml 6-thioguanine-containing medium for 10 days. The number of 6-thioguanine-resistant cell colonies formed was scored. N4-Aminocytidine had a moderate mutagenic activity, giving the induced mutation frequency of 0.12 × 10-6//tg-h/ml. N4-Amino2'-deoxycytidine was more strongly mutagenic and showed an induced mutation frequency of 1.1 × 10-6//~g-h/ml. It was suggested that the difference in the mutagenic response of microorganisms and mammalian cells to these analogs is due to the difference in metabolic activity in these organisms.
ponents were purified by means of Sephadex gel filtration, high-performance liquid chromatography and gas chromatography. A Bunsen burner connected to the city gas was used to generate the combustion products. Products of a slightly incomplete combustion, which generated 1.03 mg of particulates per hour, were found to contain directly acting mutagens, as assayed by the Ames test. The principal mutagens were identified as dinitropyrenes (1,3-, 1,6- and 1,8-isomers) and 1nitropyrene. A highly incomplete combustion, which generated 5.37 mg of particulates per hour, was found to produce various toxic agents showing direct- or indirect-acting mutagenicity. The directacting mutagens in these materials consisted of 3 isomers of dinitropyrenes and 8-nitrofluoranthrene, and the indirect-acting species were identified as benzo[a]anthracene, benzo[k]fluoranthene and benzo[a]pyrene. Materials generated from an LPG burner were also examined. Relative amounts of the identifiable mutagens in the LPG emissions were approximately the same as those of the gas burner emissions. These results suggest that in the combustion products of gas, nitropyrenes, nitrofluoranthenes and some polycyclic aromatic hydrocarbons are produced even when such gaseous fuel is burned under normal conditions.
22 Kuromoto, M., R. Nakagawa, K. Horikawa and H. Tokiwa, Epidemiology and Bacteriology Divisions, Fukuoka Environmental Research Center, Fukuoka 818-01 (Japan)
23 Kushi, A., D. Yoshida and S. Mizusaki, Central Research Institute, The Japan Tobacco & Salt Public Corporation, Yokohama, Kanagawa 227 (JapaI0
Identification of mutagens generated from gas- and liquefied-petroleum gas burners
Mutagenicity of gaseous nitrogen oxides and olefins on Salmonella TA102 and TA104
In Japan, gas and liquefied petroleum gas (LPG) are widely used for cooking and heating. The combustion products from these gases are suspected to contain several mutagens/carcinogens, in addition to some other indoor pollutants such as nitrogen dioxide and sulfur dioxide. The particulates that were formed in an incomplete combustion were collected by adsorption on XAD-2 resin. The materials were extracted with benzene-methanol, and the major mutagenic com-
The mutagenicity of NO2 and olefin compounds was examined by Salmonella tester strains TA102 and TA104, which are sensitive to oxidative mutagens and oxygen radicals. NO 2 was generated by addition of H2SO4 to an NaNO 2 solution, and the bacteria were exposed to the gas. Isoprene was used as a representative of gaseous olefins. NO 2 showed positive mutagenicity in both of the strains. A dose-response up to 100 #g NaNO 2
increased with age, which makes individual differences greater and greater in the male saline group. In the MMC group, this incidence increased with aging but decreased at the age of 80 weeks, in both males and females. In the MMC group, the 60-week-old males showed an incidence of 12%, almost twice that found in the 40-week-old males. The ratio of polychromatic erythrocytes to total erythrocytes, which indicates the hematopoietic function of the bone marrow, decreased with age up to 60 weeks in the male saline group but the ratio in the 80-week-old animals was similar to that in the 20-week-old animals. This ratio was little influenced by aging in the female saline group.
19 Kojima, M., The Biological Research Center for The Protection of Environment, Minakuchi, Koka, Shiga (Japan) Mutagenicity of anthocyanin-chromosome aberration test and mieronucleus test Recent work on the mutagenic activity of keracyanin, a kind of anthocyanin widely found as a plant pigment, has shown that keracyanin is nonmutagenic by the Salmonella/microsome activation system. We have studied the mutagenicities of keracyanin and cyanidin by the chromosome aberration test in vitro and by the micronucleus test in vivo. Keracyanin was obtained by the Mg + HC1 reduction of rutin and cyanidin was prepared by hydrolysis of keracyanin. Keracyanin was assayed by the chromosome aberration test with or without metabolic activation using Chinese hamster V79 cells, and by the micronucleus test using the bone marrow of BDF1 male mice. Cyanidin was assayed by the chromosome aberration test without metabolic activation. Incidence of cells with chromosome aberrations was elevated by 13-27% when V79 cells were exposed to keracyanin at a concentration of 2 mg/ml for 48 h without metabolic activation. Keracyanin and cyanidin were nonmutagenic in other test systems.
20 Kuroda, M., D. Yoshida and S. Mizusaki, Central Research Institute, The Japan Tabacco and Salt Public Corporation, Yokohama, Kanagawa 227 (Japan) Mutagenicity of pyrenequinone and perylenequinone on Salmonella typhimurium
Salmonella typhimurium TA97 is mutagenized by PAHs. We observed that the mutagenic response of TA97 to many PAHs was greater than that of TA98 or TA100. Pyrene and perylene were highly mutagenic to TA97. We consider that pyrene and perylene act through its metabolic conversion into quinones. Therefore, the mutagenicity of pyrenequinone and perylenequinone on TA97 was determined. Both 1,8-pyrenequinone and 3,10-perylenequinone were mutagenic without $9 mix. It was found that TA97 and the active-oxygen sensitive strains, TA102 and TA104 were sensitive to tert.-butylhydroperoxide. This suggests that the mutagenicity of these quinones is due to cellular enzyme-mediated production of active oxygen from the quinones. The mutagenicity of pyrenequinone on TA102 was increased by the addition of cell-free extract from TA97. This cell-free extract was more effective than those obtained from TA98, TA100, TA102 or TA104. No DT-diaphorase was detected in TA97.
21 Kuroda, Y., H. Hayatsu ~ and K. Negishi ~, Laboratory of Phenogenetics, Department of Ontogenetics, National Institute of Genetics, Mishima, Shizuoka 411, and ~Faculty of Pharmaceutical Sciences, Okayama University, Tsushima, Okayama 700 (Japan) Mutagenic activity of cytidine analogs in cultured mammalian cells Among analogs of nucleic acid bases and nucleosides, 5-bromouridine and 2-aminopurine were mutagenic in microorganisms, fungi and mammalian cells. Recently, it has been found that
263
a reaction product of cytidine with hydrazine, N4-aminocytidine, was strongly mutagenic to bacteria and phage. In the present experiment, the mutagenic activity of N4-aminocytidine and N 4amino-2'-deoxycytidine in cultured Chinese hamster V79 cells was examined. The cytotoxic effects of both nucleoside analogs on V79 cells were determined by scoring the colony-forming activity of cells treated with these analogs for 3 h. The LDs0 value of N4-aminocytidine was 22 /tg/ml and that of N4-amino-2'-deoxycytidine was 50/~g/ml. Cells were treated with each of the analogs for 3 h, cultured in normal medium for 6 days, replated in fresh dishes, and cultured in 5 /tg/ml 6-thioguanine-containing medium for 10 days. The number of 6-thioguanine-resistant cell colonies formed was scored. N4-Aminocytidine had a moderate mutagenic activity, giving the induced mutation frequency of 0.12 × 10-6//tg-h/ml. N4-Amino2'-deoxycytidine was more strongly mutagenic and showed an induced mutation frequency of 1.1 × 10-6//~g-h/ml. It was suggested that the difference in the mutagenic response of microorganisms and mammalian cells to these analogs is due to the difference in metabolic activity in these organisms.
ponents were purified by means of Sephadex gel filtration, high-performance liquid chromatography and gas chromatography. A Bunsen burner connected to the city gas was used to generate the combustion products. Products of a slightly incomplete combustion, which generated 1.03 mg of particulates per hour, were found to contain directly acting mutagens, as assayed by the Ames test. The principal mutagens were identified as dinitropyrenes (1,3-, 1,6- and 1,8-isomers) and 1nitropyrene. A highly incomplete combustion, which generated 5.37 mg of particulates per hour, was found to produce various toxic agents showing direct- or indirect-acting mutagenicity. The directacting mutagens in these materials consisted of 3 isomers of dinitropyrenes and 8-nitrofluoranthrene, and the indirect-acting species were identified as benzo[a]anthracene, benzo[k]fluoranthene and benzo[a]pyrene. Materials generated from an LPG burner were also examined. Relative amounts of the identifiable mutagens in the LPG emissions were approximately the same as those of the gas burner emissions. These results suggest that in the combustion products of gas, nitropyrenes, nitrofluoranthenes and some polycyclic aromatic hydrocarbons are produced even when such gaseous fuel is burned under normal conditions.
22 Kuromoto, M., R. Nakagawa, K. Horikawa and H. Tokiwa, Epidemiology and Bacteriology Divisions, Fukuoka Environmental Research Center, Fukuoka 818-01 (Japan)
23 Kushi, A., D. Yoshida and S. Mizusaki, Central Research Institute, The Japan Tobacco & Salt Public Corporation, Yokohama, Kanagawa 227 (JapaI0
Identification of mutagens generated from gas- and liquefied-petroleum gas burners
Mutagenicity of gaseous nitrogen oxides and olefins on Salmonella TA102 and TA104
In Japan, gas and liquefied petroleum gas (LPG) are widely used for cooking and heating. The combustion products from these gases are suspected to contain several mutagens/carcinogens, in addition to some other indoor pollutants such as nitrogen dioxide and sulfur dioxide. The particulates that were formed in an incomplete combustion were collected by adsorption on XAD-2 resin. The materials were extracted with benzene-methanol, and the major mutagenic com-
The mutagenicity of NO2 and olefin compounds was examined by Salmonella tester strains TA102 and TA104, which are sensitive to oxidative mutagens and oxygen radicals. NO 2 was generated by addition of H2SO4 to an NaNO 2 solution, and the bacteria were exposed to the gas. Isoprene was used as a representative of gaseous olefins. NO 2 showed positive mutagenicity in both of the strains. A dose-response up to 100 #g NaNO 2