利用彗星试验检测Cu^(2+)对驯化蚯蚓的基因损伤

Detection of Cu^(2+)-induced DNA damage of acclimated earthworms by comet assay

为研究Cu2+对驯化蚯蚓的损伤影响,将赤子爱胜蚓(Eisenia fetida)在非致死浓度(100mgCu2+·kg-1)下驯化培养2周,以未驯化的蚯蚓为对照,测定Cu2+对驯化及未驯化蚯蚓的急性毒性,并通过彗星试验(cometassay)观察铜胁迫下(400mg·kg-1)驯化后蚯蚓基因损伤的动态变化。结果显示:14d时,Cu2+对驯化蚯蚓和未驯化蚯蚓的半致死浓度(LC50)分别为321.83～542.45和230.83～342.91mg·kg-1,驯化后蚯蚓的存活率得到显著提高。彗星试验结果表示:蚯蚓体腔细胞的尾长、尾部DNA含量以及尾矩呈非正态分布,在11和14d时,驯化后的蚯蚓基因损伤程度明显比未驯化蚯蚓低。彗星试验是检测Cu2+对蚯蚓活体基因损伤的有效手段,蚯蚓体的DNA损伤可以作为指示重金属污染物影响的生物标志物。

To study the damage of Cu2＋ to acclimated earthworms,Eisenia fetida was acclimated under the exposure to a non-lethal concentration of copper（100 mg Cu2＋·kg-1） for two weeks,with the un-acclimated E.fetida as the control.The acute toxicity of Cu2＋ to the acclimated and un-acclimated E.fetida was determined,and the DNA damage of acclimated E.fetida under Cu2＋ stress（400 mg·kg-1） was detected by comet assay.On day 14,the 50% lethal concentration（LC50） of Cu2＋ for acclimated and un-acclimated E.fetida was 321.83-542.45 and 230.83-342.91 mg·kg-1,respectively,and the survival rate of acclimated E.fetida increased significantly.The comet assay showed that the tail length,tail DNA content,and tail moment of the earthworms were in non-normal distribution.On day 11 and day 14,the damaged level of DNA in acclimated E.fetida was much lower than that in un-acclimated E.fetida.The results indicated that comet assay was an effective way to detect the gene damage of living E.fetida under copper stress,and the DNA damage of E.fetida could be used as a biomarker to indicate the impacts of heavy metals pollutants.