College of Marine Life Sciences & Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
College of Marine Life Sciences & Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Evolution & Marine Biodiversity of Ministry of Education, Ocean University of China, Qingdao, 266003, China.
Environ Pollut. 2024 Nov 1;360:124667. doi: 10.1016/j.envpol.2024.124667. Epub 2024 Aug 3.
The escalating presence of microplastics and heavy metals in marine environments significantly jeopardizes ecological stability and human health. Despite this, research on the combined effects of microplastics/nanoplastics (MPs/NPs) and heavy metals on marine organisms remains limited. This study evaluated the impact of two sizes of polystyrene beads (approximately 2 μm and 200 nm) combined with cadmium (Cd) on the ciliate species Euplotes vannus. Results demonstrated that co-exposure of MPs/NPs and Cd markedly elevated reactive oxygen species (ROS) levels in ciliates while impairing antioxidant enzyme activities, thus enhancing oxidative damage and significantly reducing carbon biomass in ciliates. Transcriptomic profiling indicated that co-exposure of MPs/NPs and Cd potentially caused severe DNA damage and protein oxidation, as evidenced by numerous differentially expressed genes (DEGs) associated with mismatch repair, DNA replication, and proteasome function. Integrated transcriptomic and metabolomic analysis revealed that DEGs and differentially accumulated metabolites (DAMs) were significantly enriched in the TCA cycle, glycolysis, tryptophan metabolism, and glutathione metabolism. This suggests that co-exposure of MPs/NPs and Cd may reduce ciliate abundance and carbon biomass by inhibiting energy metabolism and antioxidant pathways. Additionally, compared to MPs, the co-exposure of NPs and Cd exhibited more severe negative effects due to the larger specific surface area of NPs, which can carry more Cd. These findings provide novel insights into the toxic effects of MPs/NPs and heavy metals on protozoan ciliates, offering foundational data for assessing the ecological risks of heavy metals exacerbated by MPs/NPs.
海洋环境中微塑料和重金属的不断增加严重威胁着生态稳定和人类健康。尽管如此，关于微塑料/纳米塑料（MPs/NPs）和重金属对海洋生物综合影响的研究仍然有限。本研究评估了两种聚苯乙烯珠大小（约 2μm 和 200nm）与镉（Cd）结合对缘毛目纤毛虫品种 Euplotes vannus 的影响。结果表明，MPs/NPs 和 Cd 的共暴露显著增加了纤毛虫体内的活性氧（ROS）水平，同时损害了抗氧化酶活性，从而增强了氧化损伤，并显著降低了纤毛虫体内的碳生物质。转录组分析表明，MPs/NPs 和 Cd 的共暴露可能导致严重的 DNA 损伤和蛋白质氧化，这可以从与错配修复、DNA 复制和蛋白酶体功能相关的大量差异表达基因（DEGs）中得到证明。整合的转录组和代谢组分析表明，DEGs 和差异积累代谢物（DAMs）在三羧酸循环、糖酵解、色氨酸代谢和谷胱甘肽代谢中显著富集。这表明 MPs/NPs 和 Cd 的共暴露可能通过抑制能量代谢和抗氧化途径来减少纤毛虫的丰度和碳生物质。此外，与 MPs 相比，由于 NPs 的比表面积更大，可以携带更多的 Cd，因此 NPs 和 Cd 的共暴露表现出更严重的负面效应。这些发现为 MPs/NPs 和重金属对原生动物纤毛虫的毒性影响提供了新的见解，为评估 MPs/NPs 加剧重金属的生态风险提供了基础数据。
