可食用文蛤中氧化性胁迫的生物标记物与甲基毒死蜱和草甘膦的生物富集

近几十年期间,在种群和个体受干扰后,对作为早期指示剂的生物标记物的研究受到越来越多的关注。我们用对水生生态系统污染敏感的生物标记物双壳类软体动物(文蛤)来评估两种有机磷杀虫剂(甲基毒死蜱、草甘膦)的影响。文蛤是水生生态系统污染的一种敏感的指示物种。在不同时间段测定文蛤中不同组织的非酶的(谷胱苷肽)和酶的(过氧化氢酶)抗氧化剂,作为文蛤中生物标记物的反应。在实验室条件下,测定了脂质过氧化作用、蛋白羰基含量、总蛋白含量、总脂质含量以及胆碱酯酶的活性。对不同的生物标记与杀虫剂的生物体内积累的相互关系进行了研究。甲基毒死蜱在文蛤组织中具有最大的诱导氧化胁迫的潜能,导致脂质过氧化反应增加并抑制抗氧化剂。而且,鳃是对该反应最敏感的器官。文蛤是一种极好的甲基毒死蜱的积聚者,因为暴露60天后,可以测定到其组织中浓度为824.0 mg/kg w.w的甲基毒死蜱。随着在草甘膦中暴露时间的增加,与背景水平相比,组织中草甘膦的浓度增加大约8×103mg/kg w.w。可以得出这样的结论:在一种生物中测定几种生物标记物是有用的。在双壳类中,蛋白质的羰基诱导可用于双壳类中化学污染物诱导的氧化胁迫的生物指示剂。抗氧化剂的防御成分是敏感的参数,是评估污染的水生生态系统的有用的生物标记物。辅以蛤组织的化学分析,生物标记参数能够提供一种有力的监测工具。

Oxidative stress biomarkers and bioconcentration of reldan and roundup by the edible clam Ruditapes decussatus

Research on biomarkers as early indicators of perturbation in populations and individuals has received increasing interest during recent decades. We used bivalve molluscs (clams), which are known to be biomarkers sensitive to aquatic ecosystem pollution, in order to assess the effects of two organophosphorus pesticides:reldan and roundup. Biomarker responses of Ruditapes decussatus were assessed by measuring non-enzymatic (glutathione; GSH) and enzymatic (catalase; CAT) antioxidants in different tissues of the clam at different time intervals. Lipid peroxidation (LPO), protein carbonyl content, total proteins and total lipid as well as the activity of cholinesterase (ChE) were evaluated under laboratory conditions. The correlations between the different biomarkers and the bioaccumulation of the pesticides were studied. Reldan had the maximum oxidative stress-inducing potential in clam tissues leading to increased LPO and inhibition of the antioxidants. Gills showed the most sensitive response. R.decussatus is an excellent accumulator of chlorpyrifos A concentration of 824.0 mg/kg w.w was detected in the tissue after 60 days of reldan exposure. Level of glyphosate increased to approximately 8×103 mg/kg w.w as compared to background level by increasing the time of exposure to roundup. It is concluded that measurement of several biomarkers in a single organism is useful. Protein carbonyl induction could be used as bioindicator of oxidative stress-inducing chemical contaminants in bivalves. Antioxidant defense components are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. Biomarker parameters, when complemented with chemical analysis of clam tissues, provide a powerful monitoring tool.