摘要
随着多溴联苯醚被逐步禁用,有机磷酸酯成为主要的替代品被广泛使用,逐渐进入到海洋环境中,给海洋生物带来极大威胁。由有机磷酸酯导致的活性氧(ROS)过多积累而产生的氧化损伤被认为是其致毒的主要机制。但在浮游植物细胞中,ROS如何被诱导产生并不清晰。本文以海洋硅藻——三角褐指藻为研究对象,利用转录组和生理生化手段,研究了浮游植物细胞ROS产生与清除过程对一种烷基有机磷酸酯——磷酸三丁酯(TnBP)的响应特征。结果表明,不同浓度TnBP胁迫(1.5、3.0和4.5μmol·L^(-1))能够诱导三角褐指藻细胞内ROS含量上升。转录组和生理生化验证结果显示,TnBP抑制了三角褐指藻的岩藻黄素-叶绿素a/c蛋白复合体捕光天线蛋白和放氧复合体关键组分的基因表达,下调了铁氧还蛋白-NADP+还原酶等电子传递链关键基因的表达量和电子传递速率,促进了ROS的产生。同时,TnBP抑制了过氧化物酶体中与货物蛋白转运相关基因的表达。在谷胱甘肽代谢途径中,TnBP虽然诱导抗坏血酸抗氧化酶活性升高,但降低了谷胱甘肽还原酶活性和基因表达,造成还原型/氧化型谷胱甘肽比值下降,表明TnBP抑制了藻细胞对ROS的清除能力,最终引起了ROS的过量积累。在所有的生理生化指标中,光合电子传递速率可以作为敏感的生物标志物来反映TnBP对浮游植物的生态毒性。研究结果将为包含TnBP在内的烷基有机磷酸酯的毒性作用模式提供依据,对于海洋生态系统中有机磷酸酯的风险评估具有实际意义。
With the gradual phasing out of polybrominated diphenyl ethers,organophosphorus esters are widely used as the main alternatives.Nowadays,they are frequently detected in the marine environment,posing a great threat to marine organism.Previous studies have shown that organophosphorus esters induced toxicity was attributed as oxidative damage via the overproduction of reactive oxygen species(ROS).However,the cause of excess ROS accumulation in phytoplankton cells is unclear.This study treated the marine diatom Phaeodactylum tricornutum as targets when exposed to an alkyl organophosphate tributyl phosphate(TnBP).The changes of the generation and scavenging of ROS were studied using transcriptomics and physiological and biochemical approaches.Results showed that different concentrations of TnBP exposure(1.5,3.0,and 4.5μmol·L^(-1))induced an increase in ROS levels in P.tricornutum cells.Transcriptomics and its subsequent physiological and biochemical validation revealed that TnBP inhibited the gene expression encoding the fucoxanthin-chlorophyll a/c protein complex and oxygen-evolving complex in P.tricornutum.The expression levels of key genes in the electron transport chain,such as ferredoxin-NADP+reductase,were downregulated,which could promote ROS production.Simultaneously,TnBP suppressed the expression of genes related to matrix protein import in peroxisomes.In the glutathione metabolic pathway,TnBP induced an increase in ascorbate peroxidase antioxidant activity but reduced the activity of glutathione reductase and its gene expression,resulting in a decrease in the ratio of reduced to oxidized glutathione.It indicated that the ability of algal cell to scavenge ROS was inhibited by TnBP exposure,inevitably leading to the excessive accumulation of ROS.Among all physiological and biochemical indicators,the photosynthetic electron transport rate is suggested to be a sensitive biomarker to reflect the ecotoxicity of TnBP on phytoplankton.These results will provide a basis for recognizing the toxic action mode of alkyl organophosphates,including TnBP,and have practical significance for the risk assessment of organophosphorus esters in the marine ecosystem.
作者
王承敏
菅潇扬
张鑫
唐学玺
张鑫鑫
Wang Chengmin;Jian Xiaoyang;Zhang Xin;Tang Xuexi;Zhang Xinxin(College of Marine Life Sciences,Ocean University of China,Qingdao 266003,China;North China Sea Environmental Monitoring Center,State Oceanic Administration,Qingdao 266000,China;Laboratory for Marine Ecology and Environmental Science,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China)
出处
《生态毒理学报》
CAS
CSCD
北大核心
2023年第4期313-323,共11页
Asian Journal of Ecotoxicology
基金
青岛海洋科学与技术试点国家实验室“十四五”重大项目(LSKJ202203900)。
关键词
磷酸三丁酯
三角褐指藻
植物毒性
氧化应激
有机磷酸酯
TnBP
Phaeodactylum tricornutum
phytotoxicity
oxidative stress
organophosphorus esters
