Department of Biology and CESAM, University of Aveiro, Aveiro, Portugal; MARE - Marine and Environmental Sciences Centre, ESTM, Polytechnic Institute of Leiria, Peniche, Portugal; Department of Biochemistry and Microbiology, Laboratory for Microbiology, Ghent University, Ghent, Belgium.
Department of Biology and CESAM, University of Aveiro, Aveiro, Portugal.
Aquat Toxicol. 2019 Nov;216:105292. doi: 10.1016/j.aquatox.2019.105292. Epub 2019 Sep 4.
Fipronil is a phenylpyrazole insecticide that entered the market to replace organochlorides and organophosphates. Fipronil impairs the regular inhibition of nerve impulses that ultimately result in paralysis and death of insects. Because of its use as a pest control, and due to runoff events, fipronil has been detected in freshwater systems near agricultural areas, and therefore might represent a threat to non-target aquatic organisms. In this study, the toxicity of fipronil to the freshwater midge Chironomus riparius was investigated at biochemical, molecular, and whole organism (e.g. growth, emergence, and behavior) levels. At the individual level, chronic (28 days) exposure to fipronil resulted in reduced larval growth and emergence with a lowest observed effect concentration (LOEC) of 0.081 μg L. Adult weight, which is directly linked to the flying performance and fecundity of midges, was also affected (LOEC = 0.040 μg L). Additionally, behavioral changes such as irregular burrowing behavior of C. riparius larvae (EC = 0.084 μg L) and impairment of adult flying performance were observed. At a biochemical level, acute (48 h) exposure to fipronil increased cellular oxygen consumption (as indicated by the increase of electron transport system (ETS) activity) and decreased antioxidant and detoxification defenses (as suggested by the decrease in catalase (CAT) and glutathione S-transferase (GST) activities). Exposure to fipronil also caused alterations in the fatty acid profile of C. riparius, since high levels of stearidonic acid (SDA) were observed. A comparison between exposed and non-exposed larvae also revealed alterations in the expression of globins, cytoskeleton and motor proteins, and proteins involved in protein biosynthesis. These alterations may aid in the interpretation of potential mechanisms of action that lead to the effects observed at the organism level. Present results show that environmentally relevant concentrations of fipronil are toxic to chironomid populations which call for monitoring of phenylpyrazole insecticides and of their ecological effects in freshwaters. Present results also emphasize the importance of complementing ecotoxicological data with molecular approaches such as proteomics, for a better interpretation of the mode of action of insecticides in aquatic invertebrates.
氟虫腈是一种苯吡唑类杀虫剂，用于取代有机氯和有机磷杀虫剂。氟虫腈通过破坏昆虫神经冲动的正常抑制作用，最终导致昆虫麻痹和死亡。由于其作为一种害虫防治剂的使用，以及由于径流事件，氟虫腈已在农业区附近的淡水系统中被检测到，因此可能对非靶标水生生物构成威胁。在这项研究中，研究了氟虫腈对淡水摇蚊 Chironomus riparius 的毒性，包括生化、分子和整体生物（如生长、出现和行为）水平。在个体水平上，慢性（28 天）暴露于氟虫腈导致幼虫生长和出现减少，最低观察到的效应浓度（LOEC）为 0.081μg/L。成虫体重也受到影响，成虫体重直接与摇蚊的飞行性能和繁殖力有关（LOEC=0.040μg/L）。此外，还观察到行为变化，如摇蚊幼虫不规则的挖掘行为（EC=0.084μg/L）和成虫飞行性能受损。在生化水平上，急性（48 小时）暴露于氟虫腈增加了细胞耗氧量（如电子传递系统（ETS）活性的增加所示），降低了抗氧化和解毒防御能力（如过氧化氢酶（CAT）和谷胱甘肽 S-转移酶（GST）活性的降低所示）。氟虫腈暴露还导致了 C. riparius 脂肪酸谱的改变，因为观察到高水平的硬脂烯酸（SDA）。暴露和未暴露幼虫之间的比较还揭示了球蛋白、细胞骨架和运动蛋白以及参与蛋白质生物合成的蛋白质的表达改变。这些变化可能有助于解释导致在生物体水平上观察到的效应的潜在作用机制。目前的结果表明，环境相关浓度的氟虫腈对摇蚊种群有毒，这需要对苯并吡唑类杀虫剂及其在淡水中的生态效应进行监测。目前的结果还强调了在水生无脊椎动物中，用蛋白质组学等分子方法补充生态毒理学数据的重要性，以便更好地解释杀虫剂的作用模式。
