This study of the combined toxic effects of zinc oxide (ZnO) and nano- and microplastics (NMPs) on the marine rotifer Brachionus koreanus demonstrates that co-exposure leads to significant physiological disruptions. The presence of NMPs increased the acute toxicity of ZnO compared to ZnO-only exposure, particularly in NP rather than MP. Combination exposure reduced both reproduction and population compared to ZnO-only exposure. We observed an increased ingestion of fluorescent MNPs in combined exposures. The ZnO + NP group showed a higher bioaccumulation of Zn compared to the ZnO and ZnO + MP groups, which resulted in increased toxicity. Also, ZnO mitigated the oxidative stress, antioxidant activity, and gene expression levels caused by NMPs. Overall, the combined exposures had more complex effects than individual exposures. ZnO altered acetylcholine esterase activity with and without NMPs, suggesting an adverse neurotoxic impact. Only the ZnO + NP group showed enhanced ERK protein level, a mitogen-activated protein kinase, suggesting a modulated cellular stress mechanism. Molecular analyses supported these in vivo findings, revealing that the combined effects of ZnO and NMPs vary by particle size, resulting in distinct toxicity pathways for NMPs. These findings highlight the need for comprehensive environmental assessments considering multiple pollutant interactions to understand their full ecological impact.

中文翻译：

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纳米塑料和微塑料与氧化锌纳米颗粒在海洋轮虫 Brachionus koreanus 中的尺寸依赖性毒性


这项关于氧化锌 （ZnO） 以及纳米和微塑料 （NMP） 对海洋轮虫 Brachionus koreanus 的综合毒性作用的研究表明，共同暴露会导致严重的生理破坏。与仅暴露于 ZnO 相比，NMP 的存在增加了 ZnO 的急性毒性，尤其是在 NP 而不是 MP 中。与仅 ZnO 暴露相比，组合暴露减少了繁殖和种群。我们观察到在联合暴露中荧光 MNP 的摄入增加。与 ZnO 和 ZnO + MP 组相比，ZnO + NP 组显示出更高的 Zn 生物蓄积性，这导致毒性增加。此外，ZnO 减轻了 NMP 引起的氧化应激、抗氧化活性和基因表达水平。总体而言，联合暴露的影响比单个暴露更复杂。ZnO 改变了乙酰胆碱酯酶活性，有和没有 NMP，表明有不良的神经毒性影响。只有 ZnO + NP 组显示 ERK 蛋白水平增强，一种丝裂原活化蛋白激酶，表明细胞应激机制的调节。分子分析支持这些体内发现，揭示了 ZnO 和 NMP 的综合作用因粒径而异，导致 NMP 具有不同的毒性途径。这些发现突出表明，需要考虑多种污染物的相互作用进行全面的环境评估，以了解其完整的生态影响。