纳米二氧化钛与镉对斜生栅藻(Scenedesmus obliquus)生长的拮抗效应及其作用机制  

Antagonistic Effect and Mechanism of Nano Titanium Dioxide and Cadmium on the Growth of Scenedesmus obliquus

作　　者：王璞 赵丽红 朱小山[1,2] WANG Pu;ZHAO Li-hong;ZHU Xiao-shan(Shenzhen International Graduate School,Tsinghua University,Shenzhen 518055,China;School of Environment,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学深圳国际研究生院,深圳518055 [2]清华大学环境学院,北京100084

出　　处：《环境科学》2021年第9期4350-4357,共8页Environmental Science

基　　金：国家自然科学基金项目(41877352,42077227);广东省促进海洋经济发展专项项目(GDOE[2019]A06);广东省自然科学基金项目(2114050000281);深圳市基础研究项目(JCYJ20180507182227257)。

摘　　要：人工纳米材料(MNMs)进入水环境将改变传统环境污染物的环境归趋及其毒性作用,两者的相互作用及其机制一直是环境科学领域的热点问题.迄今为止,已有大量MNMs与现存污染物联合毒性作用的研究成果发表,但其潜在的作用机制,尤其是联合作用下的生物响应机制仍未清楚.本文以典型MNMs——纳米二氧化钛(nTiO_(2))与重金属镉(Cd^(2+))为研究目标,以斜生栅藻(Scenedesmus obliquus)为受试生物,考察在等效剂量(毒性比1∶1)下不同浓度组合nTiO_(2)和Cd^(2+)对斜生栅藻的联合毒性作用模式及其分子机制.结果表明,等效剂量下Cd^(2+)和nTiO_(2)的72h EC50值对比单独暴露时均有显著升高,呈拮抗效应.进一步开展转录组学分析发现,nTiO_(2)存在下斜生栅藻能量代谢所涉及的光合作用、叶绿素代谢以及淀粉与蔗糖代谢通路发生了显著上调,与藻细胞抗逆效应相关的精氨酸与脯氨酸代谢通路同样呈正向刺激表现.本文首次报道了nTiO_(2)与Cd^(2+)等效剂量联合暴露下,浮游植物通过改变藻细胞抗逆能力与加强能量代谢来降低毒性的生物响应机制.本研究结果为深入理解MNMs与现存污染物的复合环境健康效应提供重要参考和研究基础.The release of manufactured nanomaterials( MNMs) into the environment has raised concerns about combined toxicological risks,as MNMs could significantly alter the environmental behavior and fate of co-existing contaminants. Numerous studies have been published on the combined toxicity of MNMs and co-existing contaminants,but the potential mechanisms controlling the combined toxicity,especially the biological response mechanism,remain unclear. This study investigated the combined toxicity of nano-titanium dioxide( nTiO_(2)),a typical MNM,and the heavy metal cadmium( Cd^(2+)),using Scenedesmus obliquus as the test organism. The molecular mechanism was examined under different concentrations,using an equivalent dose( toxic ratio 1 ∶ 1) on S. obliquus. The results showed that the 72 h-EC50 of nTiO_(2) and Cd^(2+)at the equivalent dose was significantly higher than that of single exposure,indicating an antagonistic effect. Further transcriptomics analysis revealed that the photosynthesis,chlorophyll metabolism,and starch and sucrose metabolism pathways involved in the energy metabolism of S. obliquus were significantly up-regulated in the presence of nTiO_(2). The arginine and proline metabolic pathways related to the anti-stress effect of algae cells also showed positive stimulation. The results of this study provide an important reference and a research basis for in-depth understanding of the environmental effects of MNMs and co-existing contaminants.

关 键 词：纳米二氧化钛(nTiO2) 镉 等效剂量 拮抗 转录组学 人工纳米材料(MNMs) 

分 类 号：X171.5[环境科学与工程—环境科学]