State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
Department of Environmental Engineering, School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072, China.
Chemosphere. 2020 Sep;255:126914. doi: 10.1016/j.chemosphere.2020.126914. Epub 2020 May 1.
Microplastics have aroused widespread concern because of their adverse effects on aquatic organisms. However, the underlying toxicity mechanisms have not been examined in detail. This study investigated the interactions between polystyrene microplastics (PS-MPs) and the model freshwater microalgae Euglena gracilis. The results of transmission electron microscopy showed that the vacuoles of microalgae were induced after 24 h exposure to 1 mg/L PS-MPs (5 μm and 0.1 μm). Furthermore, PS-MPs significantly (p < 0.05) reduced pigment contents. Moreover, superoxide dismutase activities were significantly (p < 0.05) induced in all PS-MPs treated groups. Peroxidase activities were also significantly (p < 0.05) affected by two sizes of PS-MPs (5 μm and 0.1 μm), indicating that oxidative stress was induced after exposure to PS-MPs. At the molecular level, PS-MPs dysregulated the expression of genes involved in cellular processes, genetic information processing, organismal systems, and metabolisms. The KCS gene and the CTR1 gene may be key pathways to induce adverse effects on the E. gracilis after exposure to 5 μm PS-MPs. These findings will help to elucidate the underlying molecular mechanism of microplastics toxicity on freshwater organisms.
微塑料因其对水生生物的不利影响而引起了广泛关注。然而，其潜在的毒性机制尚未得到详细研究。本研究调查了聚苯乙烯微塑料（PS-MPs）与模式淡水微藻眼虫之间的相互作用。透射电子显微镜的结果表明，在暴露于 1mg/L PS-MPs（5μm 和 0.1μm）24 小时后，微藻的液泡被诱导。此外，PS-MPs 显著（p<0.05）降低了色素含量。此外，所有 PS-MPs 处理组的超氧化物歧化酶活性均显著（p<0.05）诱导。过氧化物酶活性也受到两种尺寸的 PS-MPs（5μm 和 0.1μm）的显著（p<0.05）影响，表明 PS-MPs 暴露后诱导了氧化应激。在分子水平上，PS-MPs 失调了与细胞过程、遗传信息处理、生物体系统和代谢相关的基因的表达。KCS 基因和 CTR1 基因可能是 5μm PS-MPs 暴露后对眼虫产生不利影响的关键途径。这些发现将有助于阐明微塑料对淡水生物毒性的潜在分子机制。
