Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, 105 McGill St., Montreal, QC H2E 2E7, Canada.
Aquatic Contaminants Research Division, Water Science and Technology Directorate, Environment and Climate Change Canada, 105 McGill St., Montreal, QC H2E 2E7, Canada.
Sci Total Environ. 2019 May 15;665:797-809. doi: 10.1016/j.scitotenv.2019.02.155. Epub 2019 Feb 13.
Multiple metabolic, immune and reproductive effects have been reported in fish residing in effluent-impacted sites. Natural stressors such as parasites also have been shown to impact the responses of organisms to chronic exposure to municipal effluent in the St. Lawrence River (Quebec, Canada). In order to comprehensively evaluate the cumulative impacts of anthropogenic and natural stressors on the health of yellow perch, differential mRNA transcription profiles were examined in juvenile females collected from effluent-impacted and upstream sites with low or high infection levels of the larval trematode Apophallus brevis. Transcriptomics was used to identify biological pathways associated with environmental exposure. In total, 3463 isoforms were differentially transcribed between sites. Patterns reflecting the combined effects of stressors were numerically dominant, with a majority of downregulated transcripts (68%). The differentially expressed transcripts were associated with 27 molecular and cellular functions ranging from cellular development to xenobiotic metabolism and were involved in the development and function of 13 organ systems including hematological, hepatic, nervous, reproductive and endocrine systems. Based on RNA-seq results, sixteen genes were measured by qPCR. Significant differences were observed for six genes in fish exposed to both stressors combined, whereas parasites and effluent individually impacted the transcription of one gene. Lysozyme activity, lipid peroxidation, retinol-binding protein and glucose-6-phosphate dehydrogenase were selected as potential biomarkers of effects to study specific pathways of interest. Lipid peroxidation in perch liver was different between sites, parasite loads, and for combined stressors. Overall, results indicated that juvenile yellow perch responded strongly to combined parasite and effluent exposure, suggesting cumulative effects on immune responses, inflammation and lipid metabolism mediated by retinoid receptors. The present study highlight the importance of using a comprehensive approach combining transcriptomics and endpoints measured at higher levels of biological organization to better understand cumulative risks of contaminants and pathogens in aquatic ecosystems.
在受废水影响的地点生活的鱼类已报告出现多种代谢、免疫和生殖效应。自然胁迫因子，如寄生虫，也被证明会影响生物体对圣劳伦斯河（加拿大魁北克）城市废水中的慢性暴露的反应。为了全面评估人为和自然胁迫因子对黄鲈健康的累积影响，从受废水影响和上游低感染水平和高感染水平的幼虫短口吸虫的幼体雌性中检查了差异 mRNA 转录谱。转录组学用于鉴定与环境暴露相关的生物途径。总共，在受污染和上游站点之间，有 3463 个同工型转录差异。反映胁迫综合效应的模式在数量上占主导地位，大多数下调转录本（68%）。差异表达的转录本与 27 个分子和细胞功能相关，从细胞发育到异生物质代谢，涉及 13 个器官系统的发育和功能，包括血液学、肝脏、神经、生殖和内分泌系统。根据 RNA-seq 结果，通过 qPCR 测量了 16 个基因。在同时暴露于两种胁迫因子的鱼类中，观察到六个基因存在显著差异，而寄生虫和废水单独影响一个基因的转录。溶菌酶活性、脂质过氧化、视黄醇结合蛋白和葡萄糖-6-磷酸脱氢酶被选为研究特定感兴趣途径的潜在效应生物标志物。鲈鱼肝脏中的脂质过氧化作用在不同地点、寄生虫负荷以及在联合胁迫因子下均存在差异。总体而言，结果表明，幼年黄鲈对寄生虫和废水的联合暴露反应强烈，表明视黄酸受体介导的免疫反应、炎症和脂质代谢的累积效应。本研究强调了使用结合转录组学和在更高生物组织水平测量的终点的综合方法的重要性，以更好地理解水生生态系统中污染物和病原体的累积风险。
