肥皂草素对斑玉蕈菌丝体抗氧化酶活性及相关基因表达量的影响

【目的】研究肥皂草素对斑玉蕈菌丝体的活性氧代谢、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性及其基因表达的影响。【方法】在摇瓶培养基中添加不同浓度的肥皂草素研究菌丝体在不同培养时间内活性氧代谢、SOD和CAT的活性及其基因表达的变化。【结果】添加肥皂草素后，在7?11 d内超氧阴离子及丙二醛(MDA)的含量整体较对照组有升高趋势，但是在13?15 d含量较对照又有所下降；肥皂草素处理的菌丝体SOD活性随着浓度的增加而逐渐增强(第9天除外)，特别是在培养13?15 d更加明显；CAT活性同样随着浓度的增加而逐渐增强，特别是0.05 g/L实验组酶活性始终保持在较高的水平；不同浓度的肥皂草素都能使Mn-SOD基因、CAT基因的表达出现上调趋势，在0.05 g/L时，肥皂草素诱导Mn-SOD基因的表达与其活性的变化趋势基本一致，而CAT基因表达与其活性的变化并不一致，其活性可能受基因翻译后的修饰调控等因素的影响。【结论】肥皂草素的添加能够诱导SOD和CAT酶活性的增强及上调Mn-SOD、CAT基因的表达量，减缓菌丝培养后期活性氧和MDA的积累。

Effects of saponin on activities and gene expressions of antioxidant enzyme in Hypsizygus marmoreus mycelium

Objective] To examine the effects of saponin on the metabolism of reactive oxygen species (ROS), the activities and the gene expressions of superoxide dismutase (SOD) and catalase (CAT) in Hypsizygus marmoreus mycelium. Methods] Hypsizygus marmoreus mycelium were treated with 0, 0.01, 0.05 g/L saponin for 7 to 15 days under shake-flask culture condition. Results] The content of superoxide radical and MDA increased than the control group during 7 to 11 days adding saponin to the culture, and then decreased than the control group after 13 days. SOD activities enhanced with the increasing of saponin concentration during 7 to 15 days (except the 9th day), especially during 13 to 15 days. CAT activities showed the same trends as SOD activities, and always kept a high level with 0.05 g/L saponin exposure. The abundance of Mn-SOD and CAT genes were up-regulated in all concentration treatments. With 0.05 g/L treatment, the expression of gene encoding Mn-SOD showed the same trend as SOD activities. However, expression of CAT gene was not in accordance with the trend of CAT activities. It inferred that CAT activities might effected by post-translational modification. Conclusion] Saponin can induce the increase of antioxidant enzyme activities of SOD and CAT, as well as up-regulate corresponding gene expressions, which might slow down the accumulation of MDA and superoxide radical in the later culture period.