UV-B辐射对大型海藻鼠尾藻抗氧化酶活性及同工酶谱的影响

Effect of UV-B Irradiation on the Activity and Isoforms of Antioxidant Enzymes in the Brown Alga Sargassum thunbergii(Mert.) O.Kuntze

选择1种代表性的潮间带大型海藻鼠尾藻(Sargassum thunbergii)为试材,研究了其抗氧化酶体系对不同剂量UV-B胁迫的响应。结果显示,SOD及其CAT酶活性与UV-B辐射的剂量和时间关系密切,而POX活性与此相关不显著。各处理和对照中均未测出有效的APX活性。抗氧化剂AsA含量在低、中剂量UV-B辐射时呈增加趋势。SOD同工酶谱受到UV-B辐射的显著影响。中度剂量下CAT酶出现新的谱带(CATⅡ)。低、中剂量胁迫下POXⅡ活性有轻微增加,而在此次研究中,未能检测到APX同工酶谱带。这些结果表明鼠尾藻中SOD与CAT酶活性及AsA水平对UV-B辐射增强响应最敏感,在该藻抗紫外胁迫的应激反应体系中处于核心地位。

The response of the antioxidant defense system of a representative intertidal macroalga of S. thunbergii in coping with different dosages of UV-B irradiation was investigated. Superoxide dimutase（SOD） and catalase（CAT） were active in lieu of peroxidase（POX） depending on the dosage and exposure time of UV-B irradiation. No effective activity of ascorbate peroxidase（APX） was detected in either the control or the treatment group. AsA concentration increased with Luv and Muv（Low and medium dosage of UV-B irradiation） exposure. Some bands of SOD isoenzyme were also influenced by UV-B irradiation. An additional CAT band（CAT II ） was observed in the Muv treatment. POX 11 isoenzyme activity slightly increased under Luv and Muv treatments. However, no APX isoenzyme was detected in this study. These data suggest that the activity of SOD and CAT and AsA level played a key role against UV-B induced oxidative damage.