Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China.
Key Laboratory of Biodiversity of Aquatic Organisms, College of Life Science and Technology, Harbin Normal University, Harbin, 150025, China.
Ecotoxicol Environ Saf. 2020 Jan 15;187:109825. doi: 10.1016/j.ecoenv.2019.109825. Epub 2019 Oct 31.
In recent years, the release of nanomaterials pollutants to water bodies, to a great extent, attributed to anthropogenic activities. Their impacts on aquatic organisms as well as nanomaterial monitoring and bioremediation using organism have drawn much attentions. However, studies on relationship of nano-contaminants and aquatic organisms are very scarce. Our results showed that titanium dioxide nanoparticles (TiO-NPs) and Multi-walled carbon nanotubes (MWCNTs) caused an obvious cell decreases on the whole, but a significant increase at 48 h TiO-NPs exposure, indicating a resistant mechanism in ciliates for nano-toxic. Besides, MWCNTs was more toxic to Pseudocohnilembus persalinus than that of TiO-NPs in terms of EC value. It is firstly found that P. persalinus ingested and released TiO-NPs through cytostome and cytoproct, which might be the reason that TiO-NPs less toxic than MWCNTs. The significantly increased superoxide dismutase (SOD) and glutathione S-transferase (GST) enzyme activities and expression levels were evaluated by reactive oxygen species ROS generation, which demonstrated that P. persalinus antioxidant defense enzyme played roles on nano-toxic resistant in ciliates. Moreover, the integrated biomarker response (IBR) was also determined, which demonstrated that MWCNTs had comparatively higher values than those of TiO-NPs after higher concentration exposure to ciliates. In addition, it was confirmed by the present work that sod, gst and cat played different roles on immunity, and the sensitivity of cat gene expression to these two nanomaterials exposure was dissimilar. Damages of shrunk as well as losses of cilia on the cell surface caused by TiO-NPs and MWCNTs exposure in P. persalinus using SEM revealed possible physical hazards of aggregated nanomaterials. Our findings will be helpful to understand the effect mechanisms of NPs on ciliates, and also demonstrated the possibility of P. persalinus as bio-indicator of nanomaterials in aquatic and potentials on bioremediation.
近年来，纳米材料污染物向水体的释放在很大程度上归因于人为活动。它们对水生生物的影响以及利用生物进行纳米材料监测和生物修复引起了广泛关注。然而，关于纳米污染物与水生生物关系的研究还很少。我们的研究结果表明，二氧化钛纳米颗粒（TiO-NPs）和多壁碳纳米管（MWCNTs）总体上导致细胞数量明显减少，但在 48 h TiO-NPs 暴露时显著增加，表明纤毛虫对纳米毒性具有抵抗机制。此外，就 EC 值而言，MWCNTs 对 P. persalinus 的毒性比 TiO-NPs 更大。首次发现 P. persalinus 通过口沟和胞肛摄入和释放 TiO-NPs，这可能是 TiO-NPs 毒性比 MWCNTs 低的原因。通过活性氧物种（ROS）生成评估超氧化物歧化酶（SOD）和谷胱甘肽 S-转移酶（GST）酶活性和表达水平的显著增加，表明 P. persalinus 抗氧化防御酶在纤毛虫的纳米毒性抵抗中发挥作用。此外，还确定了综合生物标志物响应（IBR），结果表明，在较高浓度暴露于纤毛虫后，MWCNTs 的值比 TiO-NPs 高。此外，本工作还证实， sod、gst 和 cat 在免疫方面发挥着不同的作用，并且 cat 基因表达对这两种纳米材料暴露的敏感性不同。使用 SEM 观察到 TiO-NPs 和 MWCNTs 暴露对 P. persalinus 细胞表面的收缩和纤毛损失，这表明聚集纳米材料可能具有潜在的物理危害。我们的研究结果将有助于了解 NPs 对纤毛虫的影响机制，并展示了 P. persalinus 作为水生纳米材料生物指示剂的可能性及其在生物修复方面的潜力。
