School of Resource and Environmental Sciences, Hubei Biomass-Resource Chemistry and Environmental Biotechnology Key Laboratory, Wuhan University, Wuhan, Hubei, 430079, PR China.
Key Laboratory of Molecular Biophysics of Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, 430074, PR China.
Environ Pollut. 2021 Sep 1;284:117413. doi: 10.1016/j.envpol.2021.117413. Epub 2021 May 19.
The toxicity of nanoplastics to aquatic organisms has been widely studied in terms of biochemical indicators. However, there is little discussion about the underlying toxic mechanism of nanoplastics on microalgae. Therefore, the chronic effect of polystyrene (PS) nanoplastics (80 nm) on Chlorella pyrenoidosa was investigated, in terms of responses at the biochemical and molecular/omic level. It was surprising that both inhibitory and promoting effects of nanoplastcis on C. pyrenoidosa were found during chronic exposure. Before 13 days, the maximum growth inhibition rate was 7.55% during 10 mg/L PS nanoplastics treatment at 9 d. However, the inhibitory effect gradually weakened with the prolongation of exposure time. Interestingly, algal growth was promoted for 1-5 mg/L nanoplastics during 15-21 d exposure. Transcriptomic analysis explained that the inhibitory effect of nanoplastics could be attributed to suppressed gene expression of aminoacyl-tRNA synthetase that resulted in the reduced synthesis of related enzymes. The promotion phenomenon may be due to that C. pyrenoidosa defended against nanoplastics stress by promoting cell proliferation, regulating intracellular osmotic pressure, and accelerating the degradation of damaged proteins and organs. This study is conducive to provide theoretical basis for evaluating the actual hazard of nanoplastics to aquatic organisms.
纳米塑料对水生生物的毒性已在生化指标方面得到了广泛研究。然而，关于纳米塑料对微藻的潜在毒性机制却鲜有讨论。因此，本研究以圆褐固氮菌（Chlorella pyrenoidosa）为研究对象，探讨了聚苯乙烯（PS）纳米塑料（80nm）在慢性暴露条件下对其产生的生化和分子/组学层面的影响。结果令人惊讶的是，在慢性暴露期间，纳米塑料对圆褐固氮菌表现出抑制和促进的双重作用。在 9d 时，10mg/L PS 纳米塑料处理组的最大生长抑制率为 7.55%，在 13d 之前。然而，随着暴露时间的延长，抑制作用逐渐减弱。有趣的是，在 15-21d 暴露期间，1-5mg/L 纳米塑料促进了藻类的生长。转录组分析表明，纳米塑料的抑制作用可能归因于抑制了氨酰-tRNA 合成酶的基因表达，从而减少了相关酶的合成。促进现象可能是由于圆褐固氮菌通过促进细胞增殖、调节细胞内渗透压以及加速降解受损蛋白质和器官来抵御纳米塑料的胁迫。本研究有助于为评估纳米塑料对水生生物的实际危害提供理论依据。
