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低LET 辐射引起细胞死亡的主要原因是间接效应,这是现代放射生物学的原理之一。水辐射分解产物的间接效应中,OH 基很可能是导致细菌、哺乳动物细胞及噬菌体的DNA 链断裂和细胞死亡的主要原因。X 射线间接作用诱发DNA 单链断裂的修复,大都是DNA 聚合酶I 依赖系统完成的。为了探讨DNA 聚合酶I 在防止X 射线间接作用所致潜在性致死损伤中的作用,特采用缺乏DNA 聚合酶I 的E.Coli 突变株进行了研究。并在OH 基清除剂存在的情况下,测量了E.Coli 突变株对X 射线的辐射敏感性。使用的细菌包括AB3063F~-endAI,W3110thy~-pol
The main cause of cell death caused by low LET radiation is the indirect effect, which is one of the principles of modern radiobiology. Among the indirect effects of water decomposition products, the OH group is likely to be the major cause of DNA strand breaks and cell death in bacteria, mammalian cells and phages. Indirect X-ray induced DNA single-strand break repair, mostly DNA polymerase I-dependent system to complete. To investigate the role of DNA polymerase I in preventing potentially lethal damage caused by indirect effects of X-rays, we investigated the E. coli mutants lacking DNA polymerase I. The radiosensitivity of E. coli mutants to X-rays was measured in the presence of OH-scavengers. The bacteria used include AB3063F ~ -endAI, W3110thy ~ -pol