22种化学物和紫外线对λDNA的遗传毒性分析

ANALYSIS OF GENETIC TOXICITY OF 22 CHEMICALS AND ULTRAVIOLET(UV) TO λDNA

采用具有遗传毒性的受试化学物处理λＤＮＡ后，经体外包装，形成噬菌体颗粒，感染宿主菌ＬＥ３９２，噬菌斑发生率将显著降低。用这一方法对２２种化学物和紫外线测试的结果表明，丝裂霉素Ｃ等１３种受试化学物和紫外线对λＤＮＡ具有遗传毒性。根据用限制性内切酶消化和凝胶电泳分析的结果认为，丝裂霉素Ｃ（ＭＭＣ）、甲基磺酸乙酯（ＥＭＳ）和９－氨基吖啶（９－ＡＡ）对λＤＮＡ的遗传毒作用机理，可能是它们分别造成了λＤＮＡ分子发生随机断裂、ＤＮＡ交联和在碱基热点上结合的移码突变。

DNA damaged by chemical was packaged in vitro to form phage,which infected the host LE_(392),and the percentage of clear-plaques decreased obviously in result.22 chemicals and ultraviolet(UV) were tested to examine their genetic toxicity to λDNA.The results show that 13 chemicals and UV have genetic toxicity to λDNA.In another experiment,λDNA damaged by chemical was treated with restriction endonuclease,thererafter,agarose gel electrophoresis was performed.The results reval that Mitomyucin C(MMC),Ethyl methanesulfonate(EMS) and 9-Aminoaeridine(9-AA) Cause the random fragments,crosslinking and frameshift mutation in basic hotspot in λDNA respectively.