Wang Gaohong, Chen Kun, Chen Lanzhou, Hu Chunxiang, Zhang Delu, Liu Yongding
State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, The Chinese Academy of Sciences, Wuhan 430072, People's Republic of China.
Ecotoxicol Environ Saf. 2008 Jan;69(1):150-7. doi: 10.1016/j.ecoenv.2006.03.014. Epub 2006 Jun 8.
In this study, we found that UV-B radiation decreased photosynthetic activity and boosted lipid peroxidation of desert Nostoc sp., and exogenous chemicals (ascorbate acid (ASC), N-acetylcysteine (NAC), and sodium nitroprusside (SNP)) had obvious protective effects on photosynthesis and membranes under UV-B radiation. High-concentration SNP boosted the activities of antioxidant enzymes, but low-concentration SNP reduced the activities of antioxidant enzymes. Both NAC and ASC treatments of cells decreased activities of antioxidant enzymes. The results suggested that those chemicals possibly had different mechanisms of protection of algae cells against UV-B radiation. SNP might play double roles as a signal molecule in the formation of algae cell protection of Photosystem II under UV-B radiation and as a (reactive oxygen species) scavenger, while NAC and ASC might function as antioxidant reagents or precursors of other antioxidant molecules, which could protect cells directly against ROS initiated by UV-B radiation.
在本研究中，我们发现UV-B辐射降低了沙漠念珠藻的光合活性并增强了脂质过氧化作用，并且外源化学物质（抗坏血酸（ASC）、N-乙酰半胱氨酸（NAC）和硝普钠（SNP））在UV-B辐射下对光合作用和膜具有明显的保护作用。高浓度的SNP提高了抗氧化酶的活性，但低浓度的SNP降低了抗氧化酶的活性。对细胞进行NAC和ASC处理均降低了抗氧化酶的活性。结果表明，这些化学物质对藻类细胞抵御UV-B辐射可能具有不同的保护机制。SNP在UV-B辐射下藻类细胞对光系统II的保护形成过程中可能作为信号分子发挥双重作用，同时作为（活性氧）清除剂，而NAC和ASC可能作为抗氧化试剂或其他抗氧化分子的前体，可直接保护细胞免受UV-B辐射引发的活性氧的伤害。
