Yamazaki H, Oda Y, Shimada T
Osaka Prefectural Institute of Public Health, Japan.
Mutat Res. 1992 Oct;272(2):183-92. doi: 10.1016/0165-1161(92)90046-o.
Using an O-acetyltransferase-overexpressing strain Salmonella typhimurium NM2009 we measured the activities for metabolic activation of several carcinogenic arylamines to genotoxic products by rat liver microsomal cytochrome P-450 enzymes, and compared them with the activities obtained in the original tester strain Salmonella typhimurium TA1535/pSK1002 or the O-acetyltransferase-defective strain Salmonella typhimurium NM2000. Since all of the tester strains had introduced the umuC'-'lacZ gene, we could detect the genotoxic activities by measuring bacterial beta-galactosidase activity resulting from the DNA damage. In the O-acetyltransferase-defective strain NM2000 most of the arylamines tested showed weak responses in inducing umu gene expression after metabolic activation by liver microsomes. The strain NM2009, on the other hand, was found to be highly sensitive towards a variety of aromatic amines, and these activities were greater than those seen in the original tester strain S. typhimurium TA1535/pSK1002. The chemicals which marked responses in strain NM2009 include 2-aminoanthracene, 6-aminochrysene, 2-aminofluorene, 2-acetylaminofluorene, 3-methoxy-4-aminoazobenzene, O-aminoazotoluene, Glu-P-1, Trp-P-2, A alpha C, MeA alpha C, MeIQ, MeIQx and IQ. Of these procarcinogens tested MeIQ, MeIQx and IQ also showed strong cytotoxic effects in S. typhimurium NM2009 after metabolic activation by liver microsomes. Only PhIP was the substrate showing similar responses in strains TA1535/pSK1002 and NM2009. The results with the reconstituted monooxygenase system containing purified cytochrome P-450 enzymes support the above findings obtained with the liver microsomal enzyme system. Thus, the usefulness of the newly developed strain NM2009 for the detection of reactive metabolites of several carcinogenic aromatic amines after metabolism by the liver microsomal cytochrome P-450-linked monooxygenase system has been ascertained.
我们使用过表达O - 乙酰基转移酶的鼠伤寒沙门氏菌NM2009菌株，通过大鼠肝脏微粒体细胞色素P - 450酶来测定几种致癌芳胺代谢活化为遗传毒性产物的活性，并将其与原始测试菌株鼠伤寒沙门氏菌TA1535/pSK1002或O - 乙酰基转移酶缺陷型菌株鼠伤寒沙门氏菌NM2000中获得的活性进行比较。由于所有测试菌株都引入了umuC'-'lacZ基因，我们可以通过测量DNA损伤导致的细菌β - 半乳糖苷酶活性来检测遗传毒性活性。在O - 乙酰基转移酶缺陷型菌株NM2000中，大多数测试的芳胺在经肝脏微粒体代谢活化后诱导umu基因表达的反应较弱。另一方面，发现菌株NM2009对多种芳香胺高度敏感，并且这些活性大于原始测试菌株鼠伤寒沙门氏菌TA1535/pSK1002中的活性。在菌株NM2009中表现出明显反应的化学物质包括2 - 氨基蒽、6 - 氨基 Chrysene、2 - 氨基芴、2 - 乙酰氨基芴、3 - 甲氧基 - 4 - 氨基偶氮苯、O - 氨基偶氮甲苯、Glu - P - 1、Trp - P - 2、AαC、MeAαC、MeIQ、MeIQx和IQ。在这些测试的前致癌物中，MeIQ、MeIQx和IQ在经肝脏微粒体代谢活化后在鼠伤寒沙门氏菌NM2009中也表现出强烈的细胞毒性作用。只有PhIP是在菌株TA1535/pSK1002和NM2009中表现出相似反应的底物。含有纯化细胞色素P - 450酶的重组单加氧酶系统的结果支持了上述在肝脏微粒体酶系统中获得的发现。因此，已确定新开发的菌株NM2009在检测几种致癌芳香胺经肝脏微粒体细胞色素P - 450连接的单加氧酶系统代谢后的反应性代谢产物方面的有用性。
