Aoyama Kotaro, Iwahori Keisuke, Miyata Naoyuki
Hitachi Plant Engineering and Construction Co., Ltd., Matsudo, Chiba, Japan.
Mutat Res. 2003 Jul 8;538(1-2):155-62. doi: 10.1016/s1383-5718(03)00113-x.
Alkaline single-cell gel electrophoresis (comet assay) enables sensitive detection of DNA damage in eukaryotic cells induced by genotoxic agents. We performed a comet assay of unicellular green alga Euglena gracilis that was exposed to genotoxic chemicals, 1-methyl-3-nitro-1-nitrosoguanidine (MNNG), benzo[a]pyrene (BAP), mitomycin C (MMC) and actinomycin D (AMD). Tail length and tail moment in migrated DNA were measured as indications of DNA damage. MNNG and BAP were found to cause concentration-dependent increases in DNA damage. The responses were more sensitive than those of human lymphocytes under the same treatment conditions. MMC and AMD showed no positive response, as reported elsewhere. The comet assays performed at specified times after treatment revealed that the DNA damaged by MNNG and gamma-ray irradiation was repaired during the initial 1h. The results clearly show that the comet assay is useful for evaluating chemically-induced DNA damage and repair in E. gracilis. Given the ease of culturing and handling E. gracilis as well as its sensitivity, the comet assay of this alga would undoubtedly prove to be a useful tool for testing the genotoxicity of chemicals and monitoring of environmental pollution.
碱性单细胞凝胶电泳（彗星试验）能够灵敏地检测遗传毒性剂诱导的真核细胞中的DNA损伤。我们对暴露于遗传毒性化学物质1-甲基-3-硝基-1-亚硝基胍（MNNG）、苯并[a]芘（BAP）、丝裂霉素C（MMC）和放线菌素D（AMD）的单细胞绿藻纤细裸藻进行了彗星试验。测量迁移DNA中的尾长和尾矩作为DNA损伤的指标。发现MNNG和BAP会导致DNA损伤呈浓度依赖性增加。在相同处理条件下，这些反应比人类淋巴细胞的反应更敏感。MMC和AMD未显示出阳性反应，正如其他地方所报道的那样。在处理后的特定时间进行的彗星试验表明，MNNG和γ射线照射损伤的DNA在最初1小时内得到修复。结果清楚地表明，彗星试验可用于评估纤细裸藻中化学诱导的DNA损伤和修复。鉴于纤细裸藻易于培养和处理及其敏感性，这种藻类的彗星试验无疑将被证明是检测化学物质遗传毒性和监测环境污染的有用工具。
