外源一氧化氮和金属铜对海洋微藻抗氧化系统的影响

The Effect of Exogenous Nitric Oxide and Copper on the Antioxidant Systems of Marine Algae

以亚心形扁藻为研究对象,通过添加不同浓度一氧化氮(NO)(1.4×10-10～1.4×10-5 mol/L)培养,探讨NO对微藻生长、H2O2和MDA含量以及SOD活性的影响;通过对只添加金属Cu、同时添加Cu与NO实验,对微藻的H2O2和MDA含量以及SOD活性的影响进行了对比研究。结果表明,藻细胞活性氧的代谢有随NO浓度增加的趋势,同时细胞内的抗氧化酶SOD活性和MDA含量都有相应的变化,NO作为环境的"刺激物"提高了细胞内的活性氧水平,对抗氧化系统起到激活或伤害作用。在Cu胁迫下,藻细胞活性氧代谢明显提高,SOD活性提高,并导致细胞膜脂过氧化;但外源NO能明显降低活性氧的水平,并恢复SOD活性和MDA含量,对抗氧化系统起到保护作用,提高微藻的抗氧化能力。研究表明,NO在海洋浮游植物中扮演着"双重角色"——氧化剂和抗氧化剂,从而对微藻的生长起到重要的调节作用。

Platymonas subcordiformis was chosen to conduct the cultivation experiments when different concentration（1.4×10-10~1.4×10-5mol/L） of nitric oxide（NO） was added.The effect of NO on the microalgae growth was observed.The H2O2 and MDA contents and the activity of SOD of Platymonas subcordiforms were determined.The contrast study was conducted about the parameters of H2O2,MDA and SOD between the algae added copper ion only and the algae added copper ion and NO.The results were as follows： The reactive oxygen species（ROS） metabolism of algae cell had an increasing trend with the enhancing of NO concentration,and the SOD activity and the MDA contents also had corresponding change.So NO,as the environmental stimulator,could enhance the ROS level in algae cells,and had an activation or damage effect on the antioxidant systems.Under the condition of copper stresses,the reactive oxygen metabolism of algae cell increased apparently,and the SOD activity was enhanced,and the cell membrane lipid peroxidation was induced.But exogenous NO could reduce the ROS level evidently,and recover the SOD activity and the MDA contents.Therefore,NO had the protection effect on the antioxidant systems,and increases the antioxidant capability of marine microalgae.Therefore,it could be found that NO act as ＂dual roles＂ in marine phytoplankton,that is,oxidant and antioxidant,on the basis of which the algae growth was regulated.