摘要
利用琼脂糖凝胶电泳法研究了铜离子对超螺旋X174RFDNA结构的影响 .铜离子浓度为 10 -3 mol/L和 10 -4mol/L时 ,与DNA作用 2 4h后 ,可直接使质粒DNA的超螺旋结构完全转化为其它结构 .低浓度铜溶液 (10 -6mol/L)与DNA作用2 4h后 ,5 2 %的超螺旋结构发生了转化 .4 8h时 ,6 9%的超螺旋结构转化为其它结构 .在铜离子浓度一定的条件下 ,随着二者相互作用时间的延长 ,DNA超螺旋结构逐渐开环 ,断裂直至完全消失 .作用时间一定的条件下 ,铜离子浓度越高 ,越容易开环断裂 ,形成其它结构 .铜离子浓度、铜离子与DNA作用的时间以及DNA各种结构百分含量之间具有一定的剂量 效应关系 .通过测定DNA超螺旋结构的这种变化有可能发展一种相对于同一标准的比较污染物环境有害性的方法 .
The interaction of cupric ions with supercoiled DNA was investigated by agarose gel electrophoresis. Experimental results indicate that cupric ions could convert DNA structure from supercoiled to relaxed forms outside the cells in distilled water medium. At the levels of 10 -3 mol/L and 10 -4 mol/L copper, supercoiled DNA was totally converted into other forms of DNA after 24 hours. At a lower cupric level of 10 -6 mol/L, 52% supercoiled DNA was converted to other forms after 24 h and the relaxed form increased by 17% at 48h. Supercoiled form of DNA relaxed and gradually disappeared with the increase of incubation period of copper ions with the plasmid DNA. Supercoiled DNA degraded into other forms more rapidly at higher copper concentration. The percentages of different forms of DNA were related to copper concentration and incubation time. These results suggested that changes in supercoiled DNA structure may provide a rapid and sensitive method to assess the harmfulness of copper in aquatic environment.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2005年第2期185-189,共5页
Environmental Science
基金
国家重点基础研究发展规划项目 (2 0 0 2CB412 3 0 8)
中科院优秀'百人计划'资助项目
