UV-B辐射对发菜细胞活性氧及抗氧化酶活性的影响

Effect of UV-B radiation on Reactive Oxygen Species and Antioxidant Enzymes of Nostoc flagelliforme Cells

以液体悬浮培养的发菜细胞为研究对象，测定UV-B辐射处理后发菜细胞中活性氧含量和抗氧化酶活性的变化，探讨UV-B辐射对发菜细胞活性氧代谢的影响。实验结果表明，在1W／m2和5W／m2UV-B辐射下，处理时间延长，发菜细胞中的超氧阴离子（02。）与过氧化氢（H2O2）的含量显著增加，02的含量在辐射处理6h时达到最大值480．62、510。34nmol／gDW，分别为对照的160．09％和169．99％，H202的含量是持续增加，在48h达到210．24和229．89nmoVgDW。丙二醛（MDA）含量在48h时达到0．085和0．147mnol／gDW，分别为对照的251．70％和413．72％。超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的活性先升高后降低，在辐射12h时均达到最大：抗坏血酸过氧化物酶（APX）的活性在辐射初期（0-6h）呈增长趋势，随后经1w，m0UV-B辐射处理的APX活性变化不稳定，5W／m2UV-B辐射处理的APX活性迅速降低。

In order to explore the impact of ullraviolet-B （UV-B） radiation on reactive oxygen species （ROS） metabolism, the changes of reactive oxygen species（ROS） content and antioxidant enzyme activities were determined in liquid suspension cultivation of Nostoc flagelliforme cells. The results indicated that the superoxide anion （02） production and hydrogen peroxide （H2O2） content of Nostoc flagelliforme cells were increased under 1 and 5 W/m2 UV-B treatment, and the maximum of 02 production reached under UV-B treatment for 6 h, that were 480.62 and 510.34 nmol/g DW, respectively. The H202 content was increased at all times and reached 210.24 and 229.89 nmol/g DW under UV-B treatment for 48 h .The malondialdehyde （MDA） content attained 0.085 and 0.147 μmol/g DW ,which were 251.70% and 413.72% of the control exposure to UV-B for 48 h. The activities of superoxide dismutase （SOD） and catalase （CAT） reached the maximum at 12 h at both intensities. The ascorbate peroxidase （APX） activity was increased in the early radiation （0-6h）, then APX activity was unstable under 1 W/m2 UV-B treatment and declined rapidly under 5 W/m2 UV-B treatment.