title: Nitric oxide alleviates oxidative damage induced by enhanced ultraviolet-B radiation in cyanobacterium.
abstract: 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.
authors: School of Chemistry and Bioengineering, Lanzhou Jiaotong University, Lanzhou, PR China. xuelg@mail.lzjtu.cn
authors: Lingui
authors: L
authors: Xue
authors: Shiweng
authors: S
authors: Li
authors: Hongmei
authors: H
authors: Sheng
authors: Huyuan
authors: H
authors: Feng
authors: Shijian
authors: S
authors: Xu
authors: Lizhe
authors: L
authors: An
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D002338:Carotenoids / Q000032:analysis / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000201:enzymology / Q000378:metabolism* / Q000528:radiation effects*; D016166:Free Radical Scavengers / Q000494:pharmacology; D008315:Malondialdehyde / Q000032:analysis / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000032:analysis / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D020030:Nitric Oxide Donors; D013481:Superoxides; D002734:Chlorophyll; D009569:Nitric Oxide; D002338:Carotenoids; D008315:Malondialdehyde; D002374:Catalase; D013482:Superoxide Dismutase; D000077194:Chlorophyll A
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