Department of Biology, Xinyang Normal University, Xinyang, 46400, Henan Province, Peoples Republic of China.
Folia Microbiol (Praha). 2010 Jan;55(1):53-60. doi: 10.1007/s12223-010-0009-6. Epub 2010 Mar 25.
Nitric oxide (NO) stimulated the activity of plasma membrane H+-ATPase, 5'-nucleotidase, peroxidase, ascorbate peroxidase and glutathione reductase in ultraviolet B (UV-B) irradiated Chlorella pyrenoidosa. It also boosted the activity of nitrogen-metabolism enzymes such as nitrate reductase, nitrite reductase, glutamine synthetase, which were inhibited by UV-B irradiation. The chlorophyll fluorescence ratio (Fv/Fm) of the UV-B irradiated algae and decreased continuously after the cells were transferred to UV-B irradiation. A continuing decrease of the Fv/Fm was observed even after the cells were transferred to photosynthetically active radiation (PAR). After adaptation for 8 h under PAR (after treatment with nitric oxide), Fv/Fm recovered to 55 % of normal levels--without NO the value approached zero. Exogenous NO stopped the decay of chlorophyll and thylakoid membrane in cells exposed to UV-B irradiation. NO plays probably a key role in damage induced by UV-B irradiation in green algae.
一氧化氮（NO）刺激了经紫外线 B（UV-B）照射的蛋白核小球藻的质膜 H+-ATP 酶、5'-核苷酸酶、过氧化物酶、抗坏血酸过氧化物酶和谷胱甘肽还原酶的活性。它还促进了氮代谢酶的活性，如硝酸还原酶、亚硝酸还原酶、谷氨酰胺合成酶，这些酶的活性被 UV-B 照射所抑制。经 UV-B 照射的藻类的叶绿素荧光比（Fv/Fm）在细胞转移到 UV-B 照射后持续下降。即使细胞转移到光合有效辐射（PAR）后，Fv/Fm 仍继续下降。在 PAR 下适应 8 小时（用一氧化氮处理后），Fv/Fm 恢复到正常水平的 55%——没有 NO，该值接近零。外源 NO 阻止了暴露于 UV-B 照射下的细胞中叶绿素和类囊体膜的降解。NO 可能在绿藻的 UV-B 照射诱导损伤中起关键作用。
