Tris对高LET碳重离子辐照下质粒DNA链断裂的保护作用

利用100 keV/μm碳离子束(初始能量为290 MeV/u)照射溶解于纯水、10 mmol/L Tris、1 mmol/L EDTA及TE 缓冲液中的pUC19质粒DNA.通过琼脂糖凝胶电泳技术分析了不同溶液中各种形态DNA分子所占份额,并计算得到不同剂量下平均每个质粒分子中单链断裂(SSB)及双链断裂(DSB)的数目.发现Tris通过抑制SSB和DSB的产生对碳重离子辐照下的质粒DNA有明显的保护作用,而EDTA能够加剧SSB的产生而抑制DSB的形成.

Protective effects of Tris on Plasmid DNA from High-LET Carbon Beam

To probe into the effects of tris (hydroxymethyl) aminomethane on DNA irradiated by carbon beam, the plasmid pUC19 in water, 10 mmol/L Tris, 1 mmol/L EDTA or TE Buffer, was irradiated with 100 keV/μm ~(12) C~(6+) ions (original energy was 290 MeV/u). Through agarose gel electrophoresis and quantification, Tris was found to have obvious protective effects on plasmid DNA irradiated by carbon beam by inhibiting the formation of both DNA single strand breaks (SSBs) and double strand breaks (DSBs). EDTA, another component of TE Buffer, was found to promote the formation of SSBs while inhibit the formation of DSBs.