氧化石墨烯对2种海洋微藻的毒性效应研究  

Toxicological Effects of Graphene Oxide on Two Species of Marine Microalgae:Dunaliella salina and Nannochloropsis oceanic

作　　者：杜树豪 孟范平[1] 张倩[1] 彭晓玲 DU Shu-Hao;MENG Fan-Ping;ZHANG Qian;PENG Xiao-Ling(The Key Laboratory for Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China)

机构地区：[1]中国海洋大学海洋环境与生态教育部重点实验室,山东青岛266100

出　　处：《中国海洋大学学报（自然科学版）》2020年第12期115-125,共11页Periodical of Ocean University of China

基　　金：国家自然科学基金项目(41276104)资助。

摘　　要：氧化石墨烯(GO)是一种具有独特电学、热学和力学性能的新型纳米材料。随着GO在工业上的广泛应用,其通过随意排放或不适当处理而进入海洋环境的数量将不断增加,因此,评估这种纳米材料对海洋生物的潜在毒性十分必要。本研究将2种海洋微藻——盐生杜氏藻(Dunaliella salina)和海洋微拟球藻(Nannochloropsis oceanic)暴露于含GO的F/2培养基中,根据其生长、细胞形态、超微结构、光合色素、抗氧化防御系统和脂质过氧化对GO的毒性效应进行评价。结果表明,GO对2种微藻具有不同毒性,72 h EC50值分别为13.04和79.10 mg·L-1。GO纳米片层既能通过吸附直接与藻细胞表面作用,也能侵入藻细胞内部,造成2种微藻的细胞形态畸变和淀粉粒积累量增加,无细胞壁的盐生杜氏藻还出现细胞膜破损、内容物外泄、细胞核皱缩、核膜模糊不清、核质凝聚等异常现象。GO对光合色素合成具有促进作用而非抑制作用,这与细胞中淀粉的积累相一致。GO暴露引起藻细胞谷胱甘肽抗氧化系统的明显变化,包括GSH大量消耗、GPx活性受抑、GST和GR活性上扬。高浓度(100 mg·L-1)GO胁迫下细胞内MDA含量激增,表明脂质过氧化严重,而盐生杜氏藻更为明显。总之,海洋微藻对GO的敏感性与其是否存在细胞壁及其抗氧化能力有关。Graphene oxide(GO)is a new class of nanomaterial with unique electrical,thermal,and mechanical properties.With the wide application of GO in industry,its presence in marine environment will continuously increase due to random discharge or improper disposal practices.Therefore,the potential hazards of GO to the marine organisms need to be evaluated.In this study,two species of marine microalgae,Dunaliella salina and Nannochloropsis oceanic,were exposed to different concentrations of GO in F/2 culture medium.Algal growth,cell morphology,ultrastructure,photosynthetic pigments,antioxidant defense system and lipid peroxidation were used to assess the toxic effects of GO.The results showed that GO had a different toxicity to two species with the 72 h EC50 values of 13.04 and 79.10 mg·L^-1 respectively.GO nanosheets were able to interact directly with the cell surface through adsorption as well as invade the algal cells.This caused morphological aberration and starch accumulation of two microalgae.In addition,D.salina,which cell-wall was lacking,showed more abnormal phenomena such as cell membrane damage,content leakage,nuclear shrinkage,blurred nuclear envelope,chromatin condensation and so on.GO exposure showed a promotion instead of inhibition in the synthesis of photosynthetic pigments,which was consistent with the accumulation of starch in algal cells.GO exposure caused significant changes in the glutathione(GSH)-based antioxidant system in microalgae,including an excessive consumption in GSH,an inhibition of glutathione peroxidase(GPx)activity,and an increase of glutathione s-transferases(GST)and glutathione reductase(GR)activity.A sharp rise in malondialdehyde(MDA)content in cells was detected under high GO(100 mg·L^-1),suggesting a serious lipid peroxidation,and this is especially true for D.salina.In conclusion,the sensitivity of marine microalgae to GO was related to both the presence or absence of cell wall and the antioxidant capacity in algal cells.

关 键 词：氧化石墨烯(GO) 盐生杜氏藻 海洋微拟球藻 超微结构 抗氧化防御系统 

分 类 号：X171.5[环境科学与工程—环境科学]