title: UV-B-induced oxidative damage and protective role of exopolysaccharides in desert cyanobacterium Microcoleus vaginatus.
abstract: UV-B-induced oxidative damage and the protective effect of exopolysaccharides (EPS) in Microcoleus vaginatus, a cyanobacterium isolated from desert crust, were investigated. After being irradiated with UV-B radiation, photosynthetic activity (Fv/Fm), cellular total carbohydrates, EPS and sucrose production of irradiated cells decreased, while reducing sugars, reactive oxygen species (ROS) generation, malondialdehyde (MDA) production and DNA strand breaks increased significantly. However, when pretreated with 100 mg/L exogenous EPS, EPS production in the culture medium of UV-B stressed cells decreased significantly; Fv/Fm, cellular total carbohydrates, reducing sugars and sucrose synthase (SS) activity of irradiated cells increased significantly, while ROS generation, MDA production and DNA strand breaks of irradiated cells decreased significantly. The results suggested that EPS exhibited a significant protective effect on DNA strand breaks and lipid peroxidation by effectively eliminating ROS induced by UV-B radiation in M. vaginatus.
authors.affiliation: School of Resource & Environmental Science, Wuhan University, Wuhan 430079, China.
authors.forename: Lan-Zhou
authors.initials: LZ
authors.lastname: Chen
authors.forename: Gao-Hong
authors.initials: GH
authors.lastname: Wang
authors.forename: Song
authors.initials: S
authors.lastname: Hong
authors.forename: An
authors.initials: A
authors.lastname: Liu
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.forename: Yong-Ding
authors.initials: YD
authors.lastname: Liu
mesh_terms: D002734:Chlorophyll / Q000378:metabolism; D000077194:Chlorophyll A; D000458:Cyanobacteria / Q000378:metabolism / Q000528:radiation effects*; D053960:DNA Breaks; D004269:DNA, Bacterial / Q000378:metabolism / Q000528:radiation effects; D003889:Desert Climate; D008315:Malondialdehyde / Q000378:metabolism; D018384:Oxidative Stress; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D004269:DNA, Bacterial; D011135:Polysaccharides, Bacterial; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D008315:Malondialdehyde; D013395:Sucrose; D000077194:Chlorophyll A