摘要:
SOS/umu遗传毒性测试方法被广泛应用于化合物和复杂混合物遗传毒性的评价,但是目前已报道方法的实验周期长达17 h,给实验操作带来了不便,因此亟需对常规方法进行改进。建立了测试周期可小于8 h (2 h预培养,4.5 h暴露培养)的SOS/umu快速测定方法之后,应用改进后的方法对5种典型遗传毒性物质,4-硝基喹啉1-氧化物(4-NQO)、丝裂霉素C (MMC)、甲磺酸甲酯(MMS)、2-氨基蒽(2-AA)和苯并芘(BaP)进行测定,结果表明,改进后的SOS/umu方法对4-NQO、MMC、MMS、2-AA和BaP的检测限分别为0.013 ±0.0031、0.031 ±0.0028、229.18 ±60.51、2.29 ±1.22和1.28 ±0.0698 μmol·L-1,优于或者相当于报道方法。采用经典方法和改进后的方法对全国两个地区6个环境水样的遗传毒性进行测定,结果表明,两种方法检测出的6个环境水样的遗传毒性强度无显著性差异。另外,将研究方法应用于北方某市甲乙两个水厂原水、出厂水和管网水的遗传毒性评价,结果表明,两个水厂的原水、出厂水和管网水均表现出一定的直接遗传毒性,对应的4-NQO当量浓度(TEQ4-NQO)在0.0012 μg·L-1至0.0129 μg·L-1之间;加入鼠肝微粒体酶系统(S9)后,仅有乙水厂的管网水检测出极其微弱的遗传毒性效应。以上研究结果表明,改进后的SOS/umu快速测定方法能够实现在短时间(8h)内完成环境化合物及环境样品的遗传毒性检测,为筛选和评价化合物和复杂环境样品的遗传毒性提供了更为快捷的手段。
Abstract:
SOS/umu test is one of the widely used methods to determine genotoxicity of both chemicals and complex mixtures. However, more than 17-hour test cycle of published methods make it inconvenient, the growth curve of Salmonella typhimurium TA1535/pSK1002 was firstly analyzed to obtain a better method. With the modification of test method, 2 hours pre-culture with 4.5 hour exposure system were used to determine five genotoxins with different mode of action including 4-NQO, MMC, MMS, 2-AA and BaP. The results showed that the detection limits of 4-NQO, MMC, MMS, 2-AA and BaP were 0.013 0.0031、0.031 ±0.0028、229.18 ±60.51、2.29 ±1.22 and 1.28 ±0.069 μmol·L-1 respectively, better than those reported before. In addition, 6 source waters were detected,no differences were found between the genotoxic potencies using the methods published by Oda and the modified methods in the absence of S9. Additionally, the genotoxicity of six complex mixtures from raw, treated and pipe waters of two waterworks in a northern city of China were analyzed. In the absence of rat liver microsomal enzyme system (S9), positive results were induced by all the complex mixtures, with toxic equivalent quantity of 4-NQO in the concentration range of 0.0012 μg·L-1 and 0.0129 μg·L-1. Only one sample from pipe water was tested as weakly positive to S9. Therefore, the above results demonstrated that the improved SOS/umu test would be a faster but reliable way to determine genotoxicity of both compounds and complex environmental samples.
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