Ames试验假阳性的判断方法

目的:确立一种判断Ames试验假阳性的可靠方法。方法:在Ames平皿掺入试验中发现经受试物处理的TA97和TA1535的菌落数相比溶媒对照组明显增加,为了证实其是因为受试物致突变性导致的回变菌落数增加还是由受试物毒性导致的菌落数增加,对分别经受试物和阳性对照物处理的Ames菌落进行增菌培养后接种于无组氨酸的培养基上,观察比较细菌的生长情况。结果:经受试物处理的菌株不能生长在无组氨酸的培养基中,而经阳性对照物处理的菌株则可以生长在无组氨酸的培养基上,说明经受试物处理的菌株没有发生突变。结论:此方法能可靠地验证菌株是否为突变菌株,由本研究可以发现经受试物处理的菌株没有发生突变,Ames平皿掺入试验中所观察到的菌落数增加是由于受试物毒性造成的假阳性。

A Judgment Method of the False Positive Result in Ames Test

Objective： We affirmed a reliable method to judge the false positive resuh in Ames test. Meth ods： In the plate incorporation test, we found that compared with the vehicle control group the colony number of the TA97 and TA1535 were remarkably increased. In order to verify whether it is because of the mutagenicity of the test compound or the toxicity of the compound, we entichment cultured the single colony which treatment with the test compound or the positive control, then we streak inoculated the bacteria in the medium without histidine to observe their growth. Results： The bacteria which treatment with the test compound can＇t grow in the medium without histidine, but the bacteria treatment with the positive control can. That fact illustrated that the strain which treatment with the test compound did not mutate so they couldn＇t grow in culture medium without histidine. Conclusion： This method can reliably verify whether the mutant strain is, from this study we could found that the test compound doesn＇t make the strain mutation, the increasing result in the plate incorporation test was because of the toxicity of the compound.