类球红细菌对敌敌畏暴露中斑马鱼的保护作用

Protection of Zebrafish Against Dichlorvos by Rhodobacter sphaeroides

敌敌畏是广泛使用的有机磷农药之一,具有较高的水溶性,对水生动物的危害较大.为探讨敌敌畏降解菌对水体中中毒鱼类的降毒效果,测定了敌敌畏对斑马鱼(Brachydanio rerio)的急性毒性,研究了一株敌敌畏高效降解菌--类球红细菌(Rhodobacter sphaeroides)的解毒作用.结果显示:敌敌畏对斑马鱼24、48、72、96h的LC50分别为42.9、37.5、30.7、25.6mg L-1,安全浓度为2.6mg L-1,属低毒农药;在不同敌敌畏暴露浓度的养鱼水中添加类球红细菌(5×107CFU mL-1)可以显著降低斑马鱼的死亡率,28.3mg L-1和33.6mg L-1敌敌畏暴露浓度下,斑马鱼96h死亡率分别由对照组(不添加类球红细菌)的63.3%和96.7%降低到0;利用液相色谱检测了敌敌畏在添加和不添加类球红细菌的养鱼水中的降解规律,结果表明类球红细菌对斑马鱼的保护作用主要是快速降解水中的敌敌畏,并且没有产生对鱼有毒的降解产物.本研究获得了敌敌畏对斑马鱼的基础毒理学数据,同时为微生物降解水体中的农药残留提供了科学依据.

Dichlorvos（DDVP） is one of widely used organophosphate insecticides,with high water solubility and high risk to aquatic animals.In order to explore the detoxification of poisoned fish by DDVP using degrading strains,the acute toxicity of DDVP to zebrafish（Brachydanio rerio） was determined,and the detoxification by using a strain of Rhodobacter sphaeroides with high degradation capability to DDVP was investigated.The result showed that the half lethal concentration（LC50） of DDVP to zebrafish within 24,48,72 and 96 h were 42.9,37.5,30.7 and 2.6 mg L-1,respectively.The safe concentration was 2.56 mg L-1 which showed that DDVP belonged to low poisonous pesticide to zebrafish.Adding R.sphaeroides（5×107 CFU mL-1） to 28.3 mg L-1 and 33.6 mg L-1 of DDVP-exposed fish water reduced zebrafish mortality significantly from 63.3% and 96.7% both to 0 within 96 h.The degradation of DDVP was detected by HPLC in fish water with and without R.sphaeroides respectively.The result showed that the detoxification by R.sphaeroides was mainly due to DDVP degradation without poisonous degradation products to fish.