中文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) 英文关键词nano-titanium dioxide (nTiO₂)cadmiumequivalent doseantagonismtranscriptomicsmanufactured nanomaterials (MNMs)

作者	单位	E-mail
王璞	清华大学深圳国际研究生院, 深圳 518055 清华大学环境学院, 北京 100084	wang-p19@mails.tsinghua.edu.cn
赵丽红	清华大学深圳国际研究生院, 深圳 518055 清华大学环境学院, 北京 100084
朱小山	清华大学深圳国际研究生院, 深圳 518055 清华大学环境学院, 北京 100084	zhu.xiaoshan@sz.tsinghua.edu.cn

中文摘要 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（nTiO₂）与重金属镉（Cd²⁺）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nTiO₂和Cd²⁺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Cd²⁺和nTiO₂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，nTiO₂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nTiO₂与Cd²⁺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. 英文摘要 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 (nTiO₂), a typical MNM, and the heavy metal cadmium (Cd²⁺), 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 72h-EC₅₀ of nTiO₂ and Cd²⁺ 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 nTiO₂. 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.

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