College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.
Institute for Sustainable Industries and Liveable Cities, Victoria University, PO Box 14428, Melbourne, Victoria 8001, Australia.
J Hazard Mater. 2021 Oct 15;420:126591. doi: 10.1016/j.jhazmat.2021.126591. Epub 2021 Jul 6.
Microplastics (MPs) are a concerning environmental pollutant due to their adverse effects on aquatic organisms. However, the dose- and size-dependent effects of MPs on toxigenic cyanobacteria have not been extensively studied. Herein, we explored the effects of polystyrene MPs (PS-MPs) of varying particle sizes and concentrations on the growth and physiology of Microcystis aeruginosa. The results showed that exposure to 1 µm PS-MPs at a concentration of 2-10 mg L significantly inhibited the growth of M. aeruginosa in a concentration-dependent manner. After 12 days of exposure, high concentrations of 1 µm PS-MPs (≥ 2 mg L) increased levels of reactive oxygen species. Following exposure to 5 mg L PS-MPs of different particle sizes, algal growth was inhibited and oxidative stress was induced by 0.5 and 1 µm PS-MPs. At the molecular level, transcription of the atpB gene was generally downregulated in all PS-MPs treatments, while ftsH and fabZ were upregulated. Exposure to PS-MPs also altered the transcription levels of microcystin-related genes (mcyA and mcyH), causing more microcystin to be produced by M. aeruginosa. The results will be useful for understanding the toxicity of MPs toward toxigenic cyanobacteria, and evaluating the ecological risks of MPs in aquatic environments.
微塑料（MPs）是一种令人担忧的环境污染物，因为它们对水生生物有不良影响。然而，MPs 对产毒蓝藻的剂量和尺寸依赖性影响尚未得到广泛研究。在此，我们研究了不同粒径和浓度的聚苯乙烯 MPs（PS-MPs）对铜绿微囊藻生长和生理的影响。结果表明，在浓度为 2-10mg/L 时，暴露于 1µm PS-MPs 会以浓度依赖性方式显著抑制铜绿微囊藻的生长。暴露 12 天后，高浓度的 1µm PS-MPs（≥2mg/L）会增加活性氧的水平。在暴露于不同粒径的 5mg/L PS-MPs 后，0.5 和 1µm PS-MPs 抑制藻类生长并诱导氧化应激。在分子水平上，所有 PS-MPs 处理均普遍下调了 atpB 基因的转录，而 ftsH 和 fabZ 则上调。PS-MPs 的暴露还改变了与微囊藻毒素相关的基因（mcyA 和 mcyH）的转录水平，导致铜绿微囊藻产生更多的微囊藻毒素。这些结果将有助于理解 MPs 对产毒蓝藻的毒性，并评估 MPs 在水生环境中的生态风险。
