College of Environmental Science and Engineering, Ocean University of China, Qingdao 266100, China.
Key Laboratory of Marine Environment and Ecology, Ocean University of China, Ministry of Education, Qingdao 266100, China.
Toxins (Basel). 2021 Apr 20;13(4):293. doi: 10.3390/toxins13040293.
Microplastics (MP) widely distributed in aquatic environments have adverse effects on aquatic organisms. Currently, the impact of MP on toxigenic red tide microalgae is poorly understood. In this study, the strain of ATHK, typically producing paralytic shellfish toxins (PST), was selected as the target. Effects of 1 and 0.1 μm polystyrene MP with three concentration gradients (5 mg L, 25 mg L and 100 mg L) on the growth, chlorophyll (Chl ), photosynthetic activity (F/F) and PST production of ATHK were explored. Results showed that the high concentration (100 mg L) of 1 μm and 0.1 μm MP significantly inhibited the growth of ATHK, and the inhibition depended on the size and concentration of MP. Contents of Chl showed an increase with various degrees after MP exposure in all cases. The photosynthesis indicator F/F of ATHK was significantly inhibited in the first 11 days, then gradually returned to the level of control group at day 13, and finally was gradually inhibited in the 1 μm MP treatments, and promotion or inhibition to some degree also occurred at different periods after exposure to 0.1 μm MP. Overall, both particle sizes of MP at 5 and 25 mg L had no significant effect on cell toxin quota, and the high concentration 100 mg L significantly promoted the PST biosynthesis on the day 7, 11 and 15. No significant difference occurred in the cell toxin quota and the total toxin content in all treatments at the end of the experiment (day 21). All MP treatments did not change the toxin profiles of ATHK, nor did the relative molar percentage of main PST components. The growth of ATHK, Chl content, F/F and toxin production were not affected by MP shading. This is the first report on the effects of MP on the PST-producing microalgae, which will improve the understanding of the adverse impact of MP on the growth and toxin production of .
微塑料（MP）广泛分布于水生环境中，对水生生物具有不良影响。目前，MP 对产毒赤潮微藻的影响尚不清楚。本研究选择典型产生麻痹性贝类毒素（PST）的 ATHK 菌株作为目标。探讨了 1μm 和 0.1μm 聚苯乙烯 MP（浓度梯度为 5mg/L、25mg/L 和 100mg/L）对 ATHK 生长、叶绿素（Chl）、光合活性（F/F）和 PST 产量的影响。结果表明，高浓度（100mg/L）的 1μm 和 0.1μm MP 显著抑制了 ATHK 的生长，且抑制作用取决于 MP 的尺寸和浓度。在所有情况下，暴露于 MP 后 Chl 的含量都有不同程度的增加。暴露后第 11 天，ATHK 的光合作用指标 F/F 显著受到抑制，第 13 天逐渐恢复到对照组水平，随后在 1μm MP 处理中逐渐受到抑制，而 0.1μm MP 暴露后的不同时期也发生了不同程度的促进或抑制。总体而言，两种 MP 粒径在 5mg/L 和 25mg/L 时对细胞毒素配额均无显著影响，高浓度 100mg/L 在第 7、11 和 15 天显著促进 PST 生物合成。实验结束时（第 21 天），所有处理组的细胞毒素配额和总毒素含量均无显著差异。所有 MP 处理均未改变 ATHK 的毒素谱，也未改变主要 PST 成分的相对摩尔百分比。MP 处理不影响 ATHK 的生长、Chl 含量、F/F 和毒素产生。这是首次报道 MP 对产毒微藻的影响，将提高对 MP 对微藻生长和毒素产生的不良影响的认识。
