氨氮对斑马鱼3种酶活性和基因表达的影响

Effect of activity and gene expression of three enzymes on Zebrafish(Daniorerio) stressed by ammonia nitrogen

目的:从酶活性测定和酶基因表达两方面探讨氨氮对斑马鱼的毒性效应,为快速准确评价氨氮水环境质量提供理论依据。方法:以斑马鱼为受试生物,研究氨氮对其毒性效应,分别在第3d和第14d测定斑马鱼肝脏组织SOD和AChE酶活性变化,进一步运用半定量RT-PCR测定AChE、SOD以及CYP450基因相对转录量。结论:氨氮对斑马鱼96h-LC50为86.36mg·L-1;SOD和AChE酶活性在暴露3d时变化均不显著,暴露14d时前者表现为低浓度促进高浓度抑制的趋势,后者始终处于抑制状态,且具明显的剂量-效应关系;与酶活性测定相比,相应基因(SOD、CYP450和AChE)在转录水平上的变化出现更早,更灵敏,用于氨氮污染检测更具有时效性。

Objective：In order to provide a theoretical basis for the rapid and accurate evaluation of ammonia in water environment,the toxic effect of ammonia to zebra fish（Daniorerio）was discussed by two ways of enzyme activity determination and enzyme gene expression.Methods：The toxicity tests were conducted to determine the lethal toxic effect of ammonia to Daniorerio.Superoxide dismutase（SOD）and acetylcholinesterase（AChE）activities were measured after 3d and 14 d.RNA from liver was extracted and transcription amounts of AChE,Cu/Zn-SOD,CYP450 were determined by semi-quantitative RT-PCR determination.Conclusion：The 96 hof half lethal concentration（LC50）value was 86.36mg·L^-1.The activity of SOD was without obvious change after 3d,while a trend of＂more active at low concentration and less active at high concentration＂was shown after exposed by 14 days.The activity of AChE was inactive all the time and a significant＂dose-response＂relationship was observed.Compared with enzyme＇s activity,the corresponding of gene expression was more sensitive,making it more time-sensitive in the detection of ammonia pollution.