【作者】 武明珠；

【导师】 沈文飚；

【作者基本信息】 南京农业大学 ， 生物化学与分子生物学， 2009， 硕士

【摘要】 血红素加氧酶(HO)在动物体内是血红素分解代谢过程中的限速酶。最近的研究发现HO在植物体内也发挥着重要的作用。本文研究发现,单独以赤霉素(gibberellic acide, GA)处理或与HO-1诱导物高铁血红素(Hematin, Ht)和CO水溶液组合处理均导致小麦糊粉层中HO活性的提高,同时α-淀粉酶基因表达和α-淀粉酶活性也明显受诱导；用HO-1的专一性抑制剂锌原卟啉ZnPPIX预处理6 h后上述效应部分受阻断。这暗示HO可能参与GA诱导的α-淀粉酶基因表达。进一步的研究发现,Ht或CO水溶液与GA组合能够延迟GA诱导的小麦糊粉层细胞PCD; GA与Ht和CO组合处理的HO活性以及HO-1蛋白表达也明显高于GA单独处理；采用ZnPPIX预处理6 h能部分逆转上述作用,抗氧化剂BHT、DTT和AsA则能模拟Ht和CO的延迟效应。此外,与GA单独处理相比,Ht和CO和GA共处理后CAT和APX两种重要的抗氧化酶活性和相关基因表达均有明显提高。上述结果表明,HO可以延迟GA诱导的小麦糊粉层细胞PCD,并可能与HO的抗氧化有关。更多还原

【Abstract】 Heme oxygenase (HO) has been regarded as a rate-limiting enzyme in heme degradation. Recently, it was also found that HO exhibited important functions in planta. In this study, we showed that gibberellic acid (GA) with or without HO-1 inducer hematin (Ht) or carbon monoxide (CO) aqueous solution not only led to promote heme oxygenase (HO) activity in wheat aleurone layer, but also enhancedα-amylase gene expression and its enzyme activities. Whereas, application of HO-1 inhibitor zinc protoporphyrin IX (ZnPPIX) for 6 h blocks partially above processes. Together, above results suggested that HO might be involved in GA-induced a-amylase gene expression.we further found that Ht or CO plus GA treatments delays programmed cell death (PCD) elicited by GA in wheat aleurone layer as well as enhances HO activity and HO-1 protein expression, which can be reversed partially by pretreatment with HO-1 specific inhibitor ZnPPIX for 6 h. The application of the well-known antioxidant butylated hydroxyl toluene (BHT), ascorbic acid (AsA), and dithiothreitol (DTT) could mimick the antiodative effects conferred by Ht or CO treatment. Furthermore, GA with Ht or CO up-regulated CAT and APX activities and its gene expression in comparison with the sample treated with GA alone. Overall, above results illustrated that HO delays GA-induced programmed cell death in wheat aleurone layer, which might be related to its antioxidative behavior.更多还原