一氧化氮对增强的UV_B胁迫下螺旋藻生物损伤的减缓作用

为了探讨一氧化氮对增强的UV-B胁迫下螺旋藻生物学特性的影响,通过色素含量、蛋白质含量和生物量3个方面的变化证实了0.5mmol/L的一氧化氮(Nitric oxide,NO)供体硝普钠(Sodium nitroprusside,SNP)对增强UV-B胁迫下的螺旋藻(Spirulina platensis)794细胞生物损伤有明显的减缓作用。实验结果显示,NO能够显著诱导增强的UV-B胁迫下螺旋藻细胞内蛋白质含量、脯氨酸含量的提高,促进正常生长条件下螺旋藻(Spirulina platensis)794细胞内抗氧化物质GSH含量的增多,但外源NO又可以降低增强UV-B胁迫下螺旋藻细胞中GSH含量的增加。说明NO对增强UV-B胁迫下的螺旋藻794细胞有保护作用,可以减轻UV-B胁迫对螺旋藻(S.platensis)细胞引起的生物损伤。首次研究报道了增强UV-B胁迫下NO信号分子对蓝细菌———螺旋藻细胞生物损伤调节能力的影响,为进一步探讨NO信号及其与其它信号分子之间相互作用、相互关联来调节细胞的生理生化过程,以减缓UV-B胁迫下的生物损伤机理奠定了基础。

Alleviative effects of nitric oxide on the biological damage of Spirulina platensis induced by enhanced ultraviolet-B

Continuing depletion of the stratospheric ozone layer by atmospheric pollutants, in particular chlorofluorocarbons (CFCs), has resulted in an increasing incidence of solar UV-B (280-320 nm) at the Earth's surface. Enhanced UV-B radiation has been considered as important global environmental problem and results in important effects to mankind and the entire global ecosystem. Nitric oxide (NO) is not only a toxic molecule, one of reactive nitrogen species (RNS), but also an important redox-active signaling molecule. NO is really a double-edged sword, it can be either beneficial and activate defense responses in plants and animals or toxic, together with ROS. Besides those, NO can also act as a signal molecule and play very important roles in life of organisms. To study the effects of NO on the biological specific property of enhanced UV-B stressed Spirulina platensis, the chlorophyll-a, protein contents and biomass were investigated under enhanced UV-B radiation and its combination with different chemical treatment. The changes of chlorophyll-a, protein contents and biomass confirmed that 0.5 mmol/L sodium nitroprusside (SNP), a donor of nitric oxide (NO), could markedly alleviate the biological damage of cyanobacteria-Spirulina platensis 794 caused by enhanced ultraviolet-B. Further results proved that NO significantly increase the content of protein and proline. Meanwhile, the accumulation of reduced glutathione (GSH) in S. platensis cells were raised under normal growth condition. But exogenous NO could decrease the increasing of reduced glutathione (GSH) in enhanced UV-B stressed S. platensis cells. These results suggest that NO has protective effect and can strongly alleviate biological damage caused by UV-B stress in S. platensis 794 cells. For the first time, reported the effect of NO on the regulating ability of biological damage of S. platensis induced by enhanced UV-B. Therefore, further investigations will be necessary to inquire into the interaction and inter-correlation of signal molecules and the mechanism in cyanobacterium under enhanced UV-B stress.