六种重金属对大肠杆菌体内质粒DNA一级结构的影响

将质粒ｐＢＲ３２２、ｃ－Ｍｙｃ、ｐＣ５３－ＳＮ_３、ｐＴＢ２９转入大肠杆菌（Ｅｓｃｈｅｒｉｃｈｉａｃｏｌｉ）ＨＢ１０１中使其各自分别在含亚致死浓度Ｐｂ²⁺、Ｃｄ^2-、Ｚｎ²⁺、Ｃｕ²⁺、Ｍｎ²⁺、Ｈｇ²⁺的液体氨苄ＬＢ培养基中，振荡培养２４ｈ后，再将这些质粒抽提出来，通过限制性内切酶分析，研究了这些重金属离子对大肠杆菌体内质粒ＤＮＡ分子一级结构的影响。结果表明，在供试的６种重金属离子中只有Ｈｇ^２＋处理可明显导致质粒ＤＮＡ序列的改变。此外，供试６种重金属离子连续处理２４ｈ未发现可明显导致大肠杆菌体内质粒ＤＮＡ链的随机断裂。

Effects of six heavy metals on plasmid DNA sequence in vivo of E.coli HB101

Transformating the plasmids of PBR322. pC53-SN3, c-Myc and PTB29 into Escherichia coli HB101 andcultured with vibration in LB which contained separately sublethal concentration of Pb2 ,Cd2 , Zn2 ,Cu2 ,Mn2 orHg2 , constantly for 24 h,these plasmids were isolated.The effect of the heavy metals on plasmid DNA were studiedthrough the analysis of restriction fragment length polymorphism(RFLP). The result showed that only Hg2 could lead tothe change of plasmid DNA sequence. Moreover, these heavy metals did not cause the random break of the double-strandplasmid DNA after the treatment in vivo of E. coli HB 101 for 24h.