【摘要】 目的 :利用原子力显微镜 (AFM)直接观察技术 ,检测α粒子辐射对质粒DNA的损伤。方法 :照射质粒DNA吸附于云母表面 ,用AFM观察DNA的分子结构 ;用琼脂糖凝胶电泳检测开环和超螺旋结构的质粒DNA相对含量变化。结果 :AFM下清晰观察到开环、线性和超螺旋结构的质粒DNA分子。在 2Gyα粒子照射下 ,开环质粒DNA的比例就明显增多 ,并随照射剂量的增加而上升。相比之下 ,γ射线需要更大剂量照射才能产生同等的损伤效应。结论 :本文获得了AFM下辐射所致DNA损伤的直观图像 ,体外照射下α粒子对DNA的损伤大于γ射线。更多还原

【Abstract】 Objective:To examine the lesions of plasmid DNA induced by α particle exposure.Methods:The α-particle irradiated plasmid pGEM-T1 DNA was deposited on mica and was observed with Nanoscope Ⅲa atomic force microscopy. The irradiated DNA was concurrently analyzed by electrophoresis.Results:The three types of plasmid DNA molecules, i.e,open circle (OC), super coiled (SC) and linear were seen clearly under atomic force microscopy. The proportion of OC plasmid DNA was obviously increased at as less as 2?Gy of α particle exposure as compared with 10?Gy of γ-ray exposure.Conclusions:Clear image of plasmid DNA molecules was obtained using atomic force microscopy. The lesions of plasmid DNA induced by α particles were more serious than those by γ-ray with the same dose of exposure in vitro.更多还原