School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada.
Faculty of Science, Ontario Tech University, Oshawa, Ontario, Canada.
Comp Biochem Physiol Part D Genomics Proteomics. 2020 Mar;33:100656. doi: 10.1016/j.cbd.2020.100656. Epub 2020 Jan 29.
Microcystins that are cell-bound within Microcystis have demonstrated the ability to cause lethal and reproductive impairment in Daphnia, who constitute an important part of aquatic food chains and are known to feed on viable cyanobacterial cells. Recent advances in environmental toxicogenomics can be used to better understand the mechanistic effects from exposure to cell-bound microcystins in Daphnia; however, there remains a need to examine the effects of microcystins exposure as a function of dose and time in order to help elucidate the progression of (sub-)lethal effects. This study examines the effects of cell-bound microcystin exposure in Daphnia magna as a function of dose and time with shotgun proteomics in order to measure and provide insightful evidence describing functional mechanisms from, and relationships between, protein populations in response to toxic Microcystis aeruginosa. We further characterize the life-history fitness of D. magna in the presence of toxic exposure by measuring somatic growth rate. Chronic dietary exposure to cell-bound microcystins reduced the somatic growth rate of D. magna. Through proteomics analysis, we identified a significant increase in abundance of proteins related to reproductive success and development, removal of superoxide radicals, and motor activity in D. magna parents exposed to cell-bound microcystins at sub-lethal concentrations. We also identified a significant decrease in abundance of proteins related to apoptosis, metabolism, DNA damage repair, and immunity in D. magna neonates. This information will improve our understanding of the risks posed by cell-bound microcystins to cladocerans in freshwater ecosystems.
细胞内结合的微囊藻毒素已被证明能够对水蚤造成致命和生殖损伤，水蚤是水生食物链的重要组成部分，已知以活的蓝藻细胞为食。环境毒理基因组学的最新进展可用于更好地了解暴露于细胞结合微囊藻毒素后在水蚤中的作用机制；然而，仍需要研究微囊藻毒素暴露的剂量和时间效应，以帮助阐明（亚）致死效应的进展。本研究通过 shotgun 蛋白质组学研究了细胞结合微囊藻毒素暴露对大型水蚤的剂量和时间的影响，以测量并提供有见地的证据，描述了对有毒铜绿微囊藻的蛋白质群体的功能机制和关系。我们通过测量体生长率，进一步描述了有毒暴露下大型水蚤的生活史适应性。慢性饮食暴露于细胞结合的微囊藻毒素会降低大型水蚤的体生长率。通过蛋白质组学分析，我们发现暴露于亚致死浓度的细胞结合微囊藻毒素的水蚤父母体内与生殖成功和发育、清除超氧自由基以及运动活性相关的蛋白质丰度显著增加。我们还发现与凋亡、代谢、DNA 损伤修复和免疫相关的蛋白质丰度在水蚤幼体中显著降低。这些信息将提高我们对淡水生态系统中细胞结合微囊藻毒素对有甲类动物的风险的认识。
