离子束辐照对pUC18质粒DNA结构和功能影响的初步研究  

Research on Damage of Ion Beam irradiated pUC18 plasmid DNA

作　　者：李莉[1] 杨剑波[1] 李俊[1] 吴李君[1] 吴家道[1] 余增亮[1] 罗宁进 

机构地区：[1]安徽省农科院水稻研究所,中国科学院等离子体物理研究所,安徽省农科院科技情报研究所,安徽省食品发酵研究所

出　　处：《安徽农业科学》1994年第4期300-304,共5页Journal of Anhui Agricultural Sciences

摘　　要：离子束辐照ｐＵＣ１８质粒ＤＮＡ，可以造成其ＤＮＡ链的断裂。在剂量较低的情况下（５～１５×１０１５Ｎ＋／ｃｍ２），以单链断裂为主，电镜下主要呈开环结构；在相对较高的剂量下（２５×１０１５Ｎ＋／ｃｍ２），由于相对部位双链的断裂出现，电镜下可观察到线性质粒结构。经离子束辐照的质粒ＤＮＡ，其转化活性（即存活率）随处理剂量的增加而降低，且ＬａｃＺ基因也能发生较高频率的突变，与６０Ｃｏ—ｒ射线相比，在存活率相近的情况下，突变率较高。DNA damage could be induced by ion beam irradiating pUC18 plasmid.The conversion of pUC18 supercoiled molecules (SC)to relaxed open circles(OC)at a low dose(5×1015N+/cm2)was observed since DNA single-strand breaks occurred.Double-strand breaks,which could convert the plasmid to linear molecules(L),were induced at a lesser extent as increasing of dose applied.Average biological survival was measured by transformation of irradiated pUC18 plasmid to E.coli DH5a.host.Because pUC18 DNA contains the lacz promoter/operator region and a part of the lacz gene,lacz transformants showed white colonies instead of blue colonies on x-gal indicator plates.Comparing lacz mutation frequency induced by ion beam irradiation with that by 60Co-r irradiation,ion beam irradiation seemed to be more effective when their average biological survival rates were close

关 键 词：离子束 辐照 DNA 转化 突变 

分 类 号：S335.2[农业科学—作物遗传育种]