Mallick Nirupama, Mohn Friedrich H, Soeder Carl J, Grobbelaar Johan U
Agricultural and Food Engineering Department, Indian Institute of Technology, Kharagpur 721 302, India.
J Gen Appl Microbiol. 2002 Feb;48(1):1-7. doi: 10.2323/jgam.48.1.
A concentration-dependent toxicity of hydrogen peroxide (H(2)O(2)) was observed on growth yield, chlorophyll a content and chlorophyll fluorescence characteristics of the green microalga Scenedesmus obliquus under laboratory batch culture conditions. The addition of sodium nitroprusside, a nitric oxide (NO) donor, in combination with H(2)O(2) prevented chlorophyll losses, and the inhibition level of growth yield, maximum quantum yield of photosystem II (PSII) and the light-adapted quantum yield of PSII were significantly reduced. The antioxidant compounds, penicillamine and thiourea also reduced the damage caused by H(2)O(2) exposure. The protective actions of sodium nitroprusside were, however, arrested in cultures where sodium nitroprusside was supplemented in combination with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (c-PTIO), a specific scavenger of NO. The NO(3)(-)-grown Scenedesmus depicted less sensitivity to H(2)O(2) toxicity with respect to the quantum yields of PSII as compared to its NH(4)(1)-grown counterpart. The role of NO in providing protection against H(2)O(2) toxicity to the processes under study was discussed.
在实验室分批培养条件下，观察到过氧化氢（H₂O₂）对斜生栅藻的生长量、叶绿素a含量及叶绿素荧光特性具有浓度依赖性毒性。添加一氧化氮（NO）供体硝普钠与H₂O₂共同作用可防止叶绿素损失，且生长量、光系统II（PSII）的最大量子产率和PSII的光适应量子产率的抑制水平显著降低。抗氧化化合物青霉胺和硫脲也可减少H₂O₂暴露造成的损伤。然而，在添加硝普钠与NO特异性清除剂2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物（c-PTIO）的培养物中，硝普钠的保护作用被抑制。与以NH₄⁺为氮源培养的斜生栅藻相比，以NO₃⁻为氮源培养的斜生栅藻在PSII量子产率方面对H₂O₂毒性的敏感性较低。本文讨论了NO在为所研究过程提供抗H₂O₂毒性保护中的作用。
