用脉冲电场凝胶电泳研究γ射线诱导的DNA双链断裂

Fragmentations in DNA Double-strand Breaks irradiated with Gamma Ray by PFGE

用不同剂量的60Coγ射线照射GM0639细胞,利用脉冲电场电泳仪测量DNA双链断裂后的断裂片段分布.结果表明在20～100Gy的照射剂量下, γ射线引起的DNA断裂片段释放的比例(FAR)随照射剂量的增加而增加,在剂量比较大时释放的比例(FAR)趋于饱和, DNA断裂片段的平均长度随照射剂量的增加而减小,60Coγ射线对GM0639细胞的断裂产额为(6.00±0.6)×10-9Dsb/Bp/Gy.

GM0639 cells were irradiated by Gamma ray emitted from source ^60Co, and the yields and distributions of double-strand breaks （DSB） were measured by he method of pulsed-field gel electrophoresis （PFGE）. The results showed that the fractions of the activity released （FAR） of DNA increased with the increase of dose and ap- proached to a threshold （-85%） at larger doses, while the mean sizes of DNA fragments decreased when the dose increased. The yield of DSB of GM0639 induced by ^60Co Gamma rays was calculated as （6.00±0.6）×10^-9 Dsb/Bp/Gy.