Development of method for detection of DNA damages by the comet assay with Daphnia magna

研究了一种检测环境诱变剂对大型蚤DNA损伤的方法。最近开发的体内碱性单细胞凝胶电泳试验（SCG试验，彗星试验）有助于检测同一动物多个器官的体内遗传毒性。我们改进了用于大型果蝇细胞核的新彗星试验方法。确定了从大型果蝇细胞匀浆中获得细胞核组分的条件。用50 μg/ml以上的甲基磺酸甲酯（MMS）处理大型蚤30 min，其细胞核DNA损伤率明显高于对照组。认为从匀浆中提取和纯化细胞核的方法还需要进一步改进。

A method to detect DNA damages in vivo induced by environmental mutagens in water flea, Daphnia magna, was investigated. Recent development of the in vivo alkaline single cell gel electrophoresis assay (SCG assay, comet assay) facilitates the detection of in vivo genotoxicity in multiple organs from the same animal. We modified the new comet assay method for the nuclei of D.magna cells. Conditions to obtain nuclei fraction from the homogenate of D.magna cells were determined. When D.magna was treated with methyl methane sulfonate (MMS) at 50 μg/ml or more for 30 min, the frequency of DNA damaged nuclei was apparently higher compared with that observed in untreated control. It is considered that much improvement in extraction and purification of nuclei from homogenate is needed.