Xue Lingui, Li Shiweng, Sheng Hongmei, Feng Huyuan, Xu Shijian, An Lizhe
School of Chemistry and Bioengineering, Lanzhou Jiaotong University, Lanzhou, PR China.
Curr Microbiol. 2007 Oct;55(4):294-301. doi: 10.1007/s00284-006-0621-5. Epub 2007 Aug 13.
To study the role of nitric oxide (NO) on enhanced ultraviolet-B (UV-B) radiation (280-320 nm)-induced damage of Cyanobacterium, the growth, pigment content, and antioxidative activity of Spirulina platensis-794 cells were investigated under enhanced UV-B radiation and under different chemical treatments with or without UV-B radiation for 6 h. The changes in chlorophyll-a, malondialdehyde content, and biomass confirmed that 0.5 mM: sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the damage caused by enhanced UV-B. Specifically, the biomass and the chlorophyll-a content in S. platensis-794 cells decreased 40% and 42%, respectively under enhanced UV-B stress alone, but they only decreased 10% and 18% in the cells treated with UV-B irradiation and 0.5 mM: SNP. Further experiments suggested that NO treatment significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT), and decreased the accumulation of O (2)(-) in enhanced UV-B-irradiated cells. SOD and CAT activity increased 0.95- and 6.73-fold, respectively. The accumulation of reduced glutathione (GSH) increased during treatment with 0.5 mM: SNP in normal S. platensis cells, but SNP treatment could inhibit the increase of GSH in enhanced UV-B-stressed S. platensis cells. Thus, these results suggest that NO can strongly alleviate oxidative damage caused by UV-B stress by increasing the activities of SOD, peroxidase, CAT, and the accumulation of GSH, and by eliminating O (2)(-) in S. platensis-794 cells. In addition, the difference of NO origin between plants and cyanobacteria are discussed.
为研究一氧化氮（NO）对增强型紫外线 -B（UV -B，280 - 320 nm）辐射诱导的蓝藻损伤的作用，在增强型UV -B辐射下以及在有或无UV -B辐射的不同化学处理下，对钝顶螺旋藻 -794细胞进行6小时处理，研究其生长、色素含量和抗氧化活性。叶绿素 -a、丙二醛含量和生物量的变化证实，0.5 mM的一氧化氮供体硝普钠（SNP）可显著减轻增强型UV -B造成的损伤。具体而言，仅在增强型UV -B胁迫下，钝顶螺旋藻 -794细胞的生物量和叶绿素 -a含量分别下降了40%和42%，但在经UV -B照射和0.5 mM SNP处理的细胞中，它们仅下降了10%和18%。进一步实验表明，NO处理显著提高了超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性，并减少了增强型UV -B照射细胞中O₂⁻的积累。SOD和CAT活性分别提高了0.95倍和6.73倍。在正常钝顶螺旋藻细胞中，用0.5 mM SNP处理期间还原型谷胱甘肽（GSH）的积累增加，但SNP处理可抑制增强型UV -B胁迫下钝顶螺旋藻细胞中GSH的增加。因此，这些结果表明，NO可通过提高SOD、过氧化物酶、CAT的活性以及GSH的积累，并通过消除钝顶螺旋藻 -794细胞中的O₂⁻，强烈减轻UV -B胁迫引起的氧化损伤。此外，还讨论了植物和蓝藻中NO来源的差异。
