海洋桡足类对微塑料和汞污染复合作用的生理响应及其分子机理

Targeting at microplastics and mercury pollution (the major environmental problems in Chinese coastal zones), and using Calanus sinicus or Tigriopus japonicus as a model organism, this project aims to elucidate the mechanism concerning the effects of microplastics (collected from the marine environment) and mercury pollution on marine copepod from molecular to populational levels, as well as their related acclimatization/adaptation mechanism. Firstly, we will perform an acute test for microplastics and mercury pollution (alone or combined) in copepod so as to determine the impact of microplastics pollution on mercury toxicity to marine copepod and vice versa. Secondly, we try to examine the biochemical and proteomic response of copepods to microplastics and mercury pollution (alone or combined), which, together with metal content and speciation analysis in different subcellular compartments of the copepods, will help elucidate the response mechanism in marine copepod. Specifically, this study could provide a mechanistic answer to the interaction between the effects of microplastics and mercury pollution in marine copepod. Finally, we particularly intend to undertake a multi-generation study in copepod under microplastics and mercury pollution (alone or combined), and measure several important life traits (e.g., survival, egg production, hatching rate, and development time) for each generation, in order to quantify the change in copepod population dynamics. Additionally, a proteomic analysis for their adults will be done in each generation, helping reveal the acclimatization/adaptation mechanism of marine copepod against multiple stressors exemplified by microplastics and mercury pollution. Taken together, this project helps to accurately assess the influence on coastal ecosystem produced by the combined stress of microplastics and metal pollution, and also it should facilitate to make the marine ecological assessment and benchmark setting for microplastics pollution.

本项目瞄准中国近海主要环境问题—微塑料和汞污染，拟以中华哲水蚤或日本虎斑猛水蚤为研究对象，选取现场采集的微塑料为暴露源，从分子水平到种群层面来探讨环境特征微塑料和汞污染对海洋桡足类的作用机制以及该类群的适应机理：首先进行微塑料和汞污染对桡足类的急性测试，探讨微塑料效应与汞毒性之间的相互作用；开展微塑料和汞污染下桡足类的生理生化响应及其蛋白质组的分析，结合不同亚细胞组分内汞含量和形态的测定，阐述桡足类对两种胁迫的应激机制，重点揭示微塑料和汞污染对桡足类效应之间相互作用的机理；特别地开展微塑料和汞污染下桡足类的多世代培养及其蛋白质组学研究，测定桡足类的重要发育繁殖参数，衡量微塑料和汞污染对桡足类种群动态的影响，结合蛋白质组学分析，阐述桡足类对多重环境压力的适应机制。本项目可为微塑料和重金属污染的联合胁迫对近海生态系统的扰乱的评估提供理论支撑，同时有助于海洋微塑料污染的生态风险评估和基准制定。

本项目瞄准中国近海主要环境问题（微塑料和汞污染），以海洋桡足类模式种--日本虎斑猛水蚤为研究对象，利用生理、生化和生态学研究方法，结合蛋白质组学技术等，从分子水平至种群层面探讨不同微塑料污染下海洋桡足类的生理响应和恢复效应及其分子机理，同时还分别开展短期、长期多世代胁迫下不同微塑料和汞污染对桡足类的效应及其机理研究。主要发现如下：1）微塑料污染显著增加日本虎斑猛水蚤的核糖体、基因表达、肽生物合成、蛋白质翻译等生物学过程，这些生物合成过程的增加可能减少了细胞内能量储存，从而对生存和繁殖产生不利影响。有趣的是，桡足类会通过上调细胞氧化还原稳态、碳水化合物代谢、溶酶体等重要过程，促进几丁质形成，提高能量代谢，增强与应激相关防御途径的表达，从而使受抑制的存活率和繁殖力恢复正常。2）短期实验发现微塑料显著提高汞在日本虎斑猛水蚤体内的累积，而且吸附饱和后作用更强。虽然两种污染物对桡足类应激/解毒相关过程的效应存在协同作用，但在其能量代谢和生殖繁育相关基因表达中却存在拮抗效应。3）长期多世代暴露结合多组学研究手段分析表明，汞的多世代毒性显著诱导日本虎斑猛水蚤体内氧化胁迫、细胞凋亡的发生，从而抑制发育和繁殖。此外，微塑料的载体作用使更多的汞累积在桡足类体内，造成更严重的细胞凋亡，从而增加汞对桡足类发育和繁殖的影响。综上，该项目研究探讨海洋桡足类对微塑料和汞胁迫的响应机理，为环境特征微塑料和汞污染对近海生态系统的影响的准确评估提供了科技支撑，同时有助于海洋微塑料污染的生态风险评估和基准制定。