Oda Y, Shimada T, Watanabe M, Ishidate M, Nohmi T
Osaka Prefectural Institute of Public Health, Japan.
Mutat Res. 1992 Oct;272(2):91-9. doi: 10.1016/0165-1161(92)90037-m.
A sensitive umu test system for the detection of mutagenic nitroarenes has been developed using a new tester strain Salmonella typhimurium NM1011 having a high nitroreductase activity. The new strain was constructed by subcloning the bacterial nitroreductase gene into a plasmid pACYC184 and introducing the plasmid into the original strain S. typhimurium TA1535/pSK1002 harboring a fusion gene umuC'-'lacZ (pSK1002). Thus, the tester strain enabled us to monitor the genotoxic activities of various nitroarene compounds by measuring the beta-galactosidase activity in the cells. The sensitivity of strain NM1011 was compared with that of the parent tester strain S. typhimurium TA1535/pSK1002 or a nitroreductase-deficient strain S. typhimurium NM1000 with respect to the induction of umuC gene expression by 17 mutagenic nitroarenes. The newly developed strain with high nitroreductase activity had about 3 times higher nitrofurazone-reductase activity than the parent strain and was highly sensitive to the compounds 2-nitrofluorene, 1-nitronaphthalene, 2-nitronaphthalene, 1-nitropyrene, m-dinitrobenzene, 4,4'-dinitrobiphenyl, 3-nitrofluoranthene, 3,7-dinitrofluoranthene, 3,9-dinitrofluoranthene, 5-nitroacenaphthene and 2,4-dinitrotoluene. By contrast, the enzyme-deficient strain did not show any considerable response to 2-nitrofluorene, m-dinitrobenzene, 1-nitronaphthalene, 2-nitronaphthalene, 1-nitropyrene, 4,4'-dinitrobiphenyl, 3-nitrofluoranthene, 3,7-dinitrofluoranthene, 2,4-dinitrotoluene and 5-nitroacenaphthene. These results suggest that the newly developed tester strain with high nitroreductase activity is very useful for the detection of potent mutagenic nitroarene compounds.
利用具有高硝基还原酶活性的新型测试菌株鼠伤寒沙门氏菌NM1011，开发了一种用于检测诱变硝基芳烃的灵敏umu测试系统。通过将细菌硝基还原酶基因亚克隆到质粒pACYC184中，并将该质粒导入携带融合基因umuC'-'lacZ（pSK1002）的原始菌株鼠伤寒沙门氏菌TA1535/pSK1002中，构建了新菌株。因此，该测试菌株使我们能够通过测量细胞中的β-半乳糖苷酶活性来监测各种硝基芳烃化合物的遗传毒性活性。就17种诱变硝基芳烃对umuC基因表达的诱导作用而言，将菌株NM1011的敏感性与亲本测试菌株鼠伤寒沙门氏菌TA1535/pSK1002或硝基还原酶缺陷型菌株鼠伤寒沙门氏菌NM1000的敏感性进行了比较。新开发的具有高硝基还原酶活性的菌株，其呋喃西林还原酶活性比亲本菌株高约3倍，并且对2-硝基芴、1-硝基萘、2-硝基萘、1-硝基芘、间二硝基苯、4,4'-二硝基联苯、3-硝基荧蒽、3,7-二硝基荧蒽、3,9-二硝基荧蒽、5-硝基苊和2,4-二硝基甲苯等化合物高度敏感。相比之下，酶缺陷型菌株对2-硝基芴、间二硝基苯、1-硝基萘、2-硝基萘、1-硝基芘、4,4'-二硝基联苯、3-硝基荧蒽、3,7-二硝基荧蒽、2,4-二硝基甲苯和5-硝基苊没有表现出任何明显的反应。这些结果表明，新开发的具有高硝基还原酶活性的测试菌株对于检测强效诱变硝基芳烃化合物非常有用。
