离子注入对微生物细胞的刻蚀与对DNA的损伤及修复

The Etching of Cells and Damage and Repair of DNA in Deinococcus radiodurans by N + Implantation

以耐辐射异常球菌为试材， 以 Ｅｃｏｌｉ 为对照， 用显微扫描电镜和３ Ｈ－ Ｔｄ Ｒ 标记， 研究了离子注入对微生物细胞的刻蚀与对 Ｄ Ｎ Ａ 的损伤及其修复。结果表明， 注入离子对细胞存在着刻蚀损伤；中性蔗糖梯度密度离心沉降分析证明， 大剂量下离子注入可直接导致 Ｄ Ｎ Ａ 损伤， 并观察到在对应的存活率峰值注入剂量下， Ｄｒａｄｉｏｄｕｒａｎｓ 修复损伤 Ｄ Ｎ Ａ 的能力比 Ｅｃｏｌｉ 强， 还证明了细胞经不同时间温育后， 损伤的 Ｄ Ｎ Ａ 分子得到了部分修复。

The direct action of N + implantationin on D radiodurans and E coli was investigated by SEM, and their cells were labeled with 3 H-TdR, which were implanted by 20keV N + after incubation 18hours, then the DNA of lysed cells was subjected to the neutral sucrose gradient(5%～20%) ultra-centrifugation sedimentation analysis The results showed that N + implantation exerted direct action on two kinds of microorganisms; the momentum transfer and energy deposition of implantation ions produced the direct etching damage on cells, and repair DNA efficiency of D radiodurans was higher than that of E coli Meanwhile, the damaged DNA incomplete repairing was observed When incubation was continued up to 6 hours, the rejoined DNA molecules broke again The repair of damaged DNA could be inhibited by 200μg/ml chloramphenicol This suggested that DNA damage was serious by ion implantation and damaged DNA repair of cells need continuously synthesizing repair enzyme