C离子辐照对酿酒酵母DNA损伤研究

Study on DNA damage of Saccharomyces cerevisiae irradiated with C ion beams

利用不同剂量的C离子辐照酿酒酵母,研究了C离子辐照对真核生物DNA损伤的影响。使用100MeV/u12C6+辐照酵母细胞,计算细胞的存活率,使用脉冲场凝胶电泳技术分析DNA损伤的剂量效应。酵母细胞接受50 Gy辐照后,经培育筛选获得菌株CZF 303,将该菌株和原始出发菌株的乙醇脱氢酶Ⅴ的基因扩增、测序并进行比对分析。发现C离子辐照严重损伤酿酒酵母基因DNA,并产生基因突变。大剂量辐照除导致DNA双链断裂外,还导致细胞大量死亡。可以使用C离子辐照酵母菌株所致基因的点突变,作为一种优良和高效地培育高产菌种的好方法。

The different absorbed doses of 100MeV/u 12C6 ion beams was used to investigate the DNA dam- ages and relative mechanism of Saccharomyces cerevisiae. After irradiation, the survival rates were estimated, and the DNA double strand breaks （DSBs） were tested by pulsed-field gel electrophoresis （PFGE）. At the absorbed dose of 50 Gy, the yeast cells semi-lethal dose, a strains named CZF 303 was cultured after comparing the alcohol dehydro- genase V （adh4） gene sequence of CZF303 with the original strain. It was found that heavy ion beam could cause se- rious damage of yeast chromosomal DNA meanwhile large doses could cause yeast cell death. And amount of point mutations were found in adh4, which might be heritable mutations if the absorbed doses were suitable. As conclusion heavy ion irradiation can induce heritable mutations on S. cerevisiae gene. And it is an excellent and efficient method for breeding mutants.