Lüchmann Karim H, Righetto Bárbara P H, Lima Daína, Luz Hortência C, Ferreira Clarissa P, Schallenberger Bárbara H, Gomes Carlos H A M, Bainy Afonso C D
Department of Scientific and Technological Education, Santa Catarina State University, Florianópolis 88035-001, Brazil.
Laboratory of Biomarkers of Aquatic Contamination and Immunochemistry - LABCAI, Federal University of Santa Catarina, Florianópolis 88034-257, Brazil.
Aquat Toxicol. 2025 Feb;279:107225. doi: 10.1016/j.aquatox.2024.107225. Epub 2024 Dec 27.
Brazil is one of the world's leading consumers of agricultural pesticides, highlighting the urgent need to identify responsive biomarkers as diagnostic and prognostic tools for monitoring aquatic pollution. Acetylcholinesterase (AChE) and carboxylesterases (CbE) are B-esterases enzymes expressed in several organisms. AChE plays an essential role in neural transmission at cholinergic synapses, while CbE are directly involved in the detoxification of organic pollutants, including organophosphorus pesticides. The activities of AChE and CbE in bivalves have not been extensively investigated, despite their suitability as sentinel organisms for environmental monitoring. In this study, we characterized the activities of AChE and CbE in the mangrove oyster Crassostrea gasar, collected from an estuarine system in southern Brazil. We compared enzymatic activities between the gills and the digestive gland, revealing that CbE activity was significantly higher in the digestive gland, while AChE activity did not differ between the two tissues. These results indicate that the digestive gland functions as the primary metabolic organ in C. gasar. Additionally, we observed notable differences in CbE activity depending on the substrate used: ρ-nitrophenyl acetate (ρNPA), ρ-nitrophenyl butyrate (ρNPB), α-naphtyl acetate (αNA), and α-naphtyl butyrate (αNB). Our findings suggest that more lipophilic substrates are metabolized more rapidly in both the digestive gland and gills. These results enhance our understanding of the biotransformation processes and neurotoxicity potential of pesticides in oysters. However, further in vitro validation is needed to confirm the utility of these biomarkers for monitoring environmental pollution in coastal waters.
巴西是全球主要的农用杀虫剂消费国之一，这凸显了迫切需要确定反应性生物标志物，作为监测水体污染的诊断和预后工具。乙酰胆碱酯酶（AChE）和羧酸酯酶（CbE）是在多种生物中表达的B-酯酶。AChE在胆碱能突触的神经传递中起关键作用，而CbE直接参与包括有机磷农药在内的有机污染物的解毒过程。尽管双壳贝类作为环境监测的指示生物具有适用性，但尚未对其体内AChE和CbE的活性进行广泛研究。在本研究中，我们对从巴西南部一个河口系统采集的红树蚶（Crassostrea gasar）体内AChE和CbE的活性进行了表征。我们比较了鳃和消化腺之间的酶活性，发现消化腺中的CbE活性显著更高，而两种组织中的AChE活性没有差异。这些结果表明，消化腺是红树蚶的主要代谢器官。此外，我们观察到根据所使用的底物：对硝基苯乙酸（ρNPA）、对硝基苯丁酸（ρNPB）、α-萘乙酸（αNA）和α-萘丁酸（αNB），CbE活性存在显著差异。我们的研究结果表明，在消化腺和鳃中，亲脂性更强的底物代谢更快。这些结果加深了我们对牡蛎体内农药生物转化过程和神经毒性潜力的理解。然而，需要进一步的体外验证来确认这些生物标志物在监测沿海水域环境污染方面的实用性。
