Bioengineering Laboratory-CIETI, ISEP-School of Engineering, Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4249-015 Porto, Portugal; CEB-Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
REQUIMTE/LAQV, Departamento de Engenharia Química, Faculdade de Engenharia, Universidade do Porto, rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
Aquat Toxicol. 2018 Nov;204:80-90. doi: 10.1016/j.aquatox.2018.08.022. Epub 2018 Sep 1.
Over the last decade, concerns have been raised regarding the potential health and environmental effects associated with the release of metal oxide nanoparticles (NPs) into ecosystems. In the present work, the potential hazards of nickel oxide (NiO) NPs were investigated using the ecologically relevant freshwater alga Pseudokirchneriella subcapitata. NiO NP suspensions in algal OECD medium were characterized with regard to their physicochemical properties: agglomeration, surface charge, stability (dissolution of the NPs) and abiotic reactive oxygen species (ROS) production. NiO NPs formed loose agglomerates and released Ni. NiO NPs presented a 72 h-EC of 1.6 mg L, which was evaluated using the algal growth inhibition assay and allowed this NP to be classified as toxic. NiO NPs caused the loss of esterase activity (metabolic activity), the bleaching of photosynthetic pigments and the intracellular accumulation of reactive oxygen species (ROS) in the absence of the disruption of plasma membrane integrity. NiO NPs also disturbed the photosynthetic process. A reduction in the photosynthetic efficiency (Φ) accompanied by a decrease in the flow rate of electrons through the photosynthetic chain was also observed. The leakage of electrons from the photosynthetic chain may be the origin of the ROS found in the algal cells. The exposure to NiO NPs led to the arrest of the cell cycle prior to the first cell division (primary mitosis), an increase in cell volume and the presence of aberrant morphology in the algal cells. In this work, the use of different approaches allowed new clues related to the toxicity mechanisms of NiO NPs to be obtained. This work also contributes to the characterization of the environmental and toxicological hazards of NiO NPs and provides information on the possible adverse effects of these NPs on aquatic systems.
在过去的十年中，人们对金属氧化物纳米粒子（NPs）释放到生态系统中可能带来的健康和环境影响表示担忧。在本工作中，使用生态相关的淡水藻类斜生栅藻（Pseudokirchneriella subcapitata）研究了氧化镍（NiO）NPs 的潜在危害。用 OECD 藻类培养液对 NiO NP 悬浮液的理化性质进行了表征：团聚、表面电荷、稳定性（NPs 的溶解）和非生物活性氧物质（ROS）的产生。NiO NPs 形成松散的聚集体并释放出 Ni。NiO NPs 的 72 h-EC 值为 1.6 mg·L-1，通过藻类生长抑制试验进行评估，可将该 NP 归为有毒物质。NiO NPs 导致酯酶活性（代谢活性）丧失、光合作用色素漂白和细胞内活性氧物质（ROS）积累，而细胞膜完整性未被破坏。NiO NPs 还干扰了光合作用过程。观察到光合效率（Φ）降低，同时通过光合链的电子流速也降低。电子从光合链的泄漏可能是藻类细胞中发现的 ROS 的来源。暴露于 NiO NPs 会导致细胞周期在第一次细胞分裂（有丝分裂）之前停止，细胞体积增加，藻类细胞出现异常形态。在这项工作中，使用不同的方法获得了与 NiO NPs 毒性机制相关的新线索。这项工作还有助于 NiO NPs 的环境和毒理学危害的表征，并提供了有关这些 NPs 对水生系统可能产生的不利影响的信息。
