纳米二氧化铈对蛋白核小球藻的生物学效应研究

纳米二氧化铈(CeO_2)在被广泛使用的同时,其潜在的环境效应也受到人们越来越多的关注。以蛋白核小球藻(Chlorella pyrenoidosa)为实验材料,研究纳米CeO_2的生物学效应,为探索纳米材料对微藻的生物学效应提供理论基础和数据支持。研究结果显示:1)纳米CeO_2在低浓度(≤80 mg·L~(-1))时可促进蛋白核小球藻的生长及色素、可溶性蛋白等的合成,但在高浓度(80 mg·L~(-1))下具有毒性效应;2)低浓度纳米CeO_2可诱导藻细胞合成超氧化物歧化酶(superoxide dismutase,SOD)等可溶性蛋白,以抵御纳米CeO_2的胁迫;但在高浓度时又会降低SOD活力;3)随着纳米CeO_2浓度的升高,藻细胞中丙二醛(malondialdehyde,MDA)含量显著增加,说明藻细胞中活性氧自由基(reactive oxygen species,ROS)过量积累,这将破坏藻细胞的膜结构与功能,使细胞遭受严重损伤。

Effects of Nanoparticle CeO2 on the Physiology of Chlorella pyrenoidosa

Nanoparticle cerium oxide (CeO2) has been widely used in industries and material sciences.Its toxicity on the aquatic environment has been increasingly concerned recently.This study is aimed to explore effects of nanomaterials CeO2 on the physiology of a microalga, Chlorella pyrenoidosa.Results showed that low concentrations of nanoparticle CeO2 (≤80 mg·L-1) resulted in an increase of growth, pigments and soluble protein contents in C.pyrenoidosa, but high concentrations CeO2 (>80 mg·L-1) significantly inhibited the growth and synthesis of the pigments, and decreased soluble protein in C.pyrenoidosa.The superoxide dismutase (SOD) activity was enhanced in the treatment of low concentrations of the nanoparticle CeO2, while SOD activity decreased in the treatment of high concentrations of nanoparticle CeO2.Malondialdehyde (MDA) contents in C.pyrenoidosa were significantly increased with an increase of the nanoparticle CeO2 concentrations, indicating that an excessive accumulation of reactive oxygen species (ROS) may result in damage of the structure and function of the microalgal cell membrane.