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为了探索外源一氧化氮(NO)提高食用菌菌丝体耐热性的生化途径,以白灵侧耳Pleurotus eryngii var.tuoliensis菌株CCMSSC 00489为材料,通过测定高温胁迫下外源添加硝普钠(sodium nitroprusside,SNP,NO供体)后,菌丝体内超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)和过氧化物酶(POD)等4个抗氧化酶活性的变化,研究外源NO在高温胁迫响应中对抗氧化酶的影响。试验表明,高温胁迫致使菌丝体内TBARS含量升高,膜脂过氧化加剧。在正常温度培养(CK)下,外源添加SNP无显著缓解膜脂过氧化的效果,而高温胁迫条件下缓解效果显著,高温胁迫6h和12h,TBARS含量较对照(未添加)分别下降31.5%和25%。研究表明,抗氧化酶类对外源NO的响应不同。在有外源添加SNP的高温胁迫条件下,菌丝体内的SOD、CAT和GR活性随处理时间的延长而显著增强,在处理72h达到最高,分别是对照(0h)的1.73、7.29和4.95倍。其中CAT是高温胁迫响应的主要抗氧化酶类,其活力可以mmol/L·min-1·mg-1 of protein计量,而其他种类的活力均仅以μmol/L·min-1·mg-1 of protein计量。在试验条件下,这些抗氧化酶类活性的提高与TBARS含量的降低相呼应,表明外源NO通过提高SOD、CAT、GR的活性降低高温胁迫下的活性氧水平,缓解其氧化损伤,提高菌丝体耐热性。POD活性在外源添加SNP的高温胁迫条件下显著降低。
In order to explore the biochemical pathway of exogenous nitric oxide (NO) increasing the thermotolerance of mycelium of Pleurotus eryngii var. Tuoliensis, CCMSSC 00489 was used to investigate the effects of high concentration of sodium nitroprusside sodium nitroprusside, SNP and NO donor, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and peroxidase (POD) Antioxidant enzymes activities of exogenous NO in response to high temperature stress on the antioxidant enzymes. The results showed that high temperature stress caused the content of TBARS in mycelium to increase and the lipid peroxidation increased. Under normal temperature (CK), exogenous SNP did not significantly alleviate the lipid peroxidation, while under high temperature stress, the alleviating effect was remarkable. TBARS content decreased by 31.5% at 6h and 12h And 25%. Studies have shown that antioxidant enzymes respond differently to exogenous NO. The activities of SOD, CAT and GR in mycelia increased significantly with the prolongation of treatment time under the conditions of high temperature stress with exogenous SNP addition, reaching the highest at 72h, which were 1.73, 7.29 and 4.95 times of control (0h) . Among them, CAT was the main antioxidant enzyme in response to high temperature stress. The activity of CAT was measured in mmol / L · min-1 · mg-1 of protein, while the activity of other species was only in μmol / L · min-1 · mg-1 of protein measurement. Under the experimental conditions, the increase of these antioxidant enzymes activity was in accordance with the decrease of TBARS content, indicating that exogenous NO could reduce the level of reactive oxygen species under high temperature stress by increasing the activities of SOD, CAT and GR, relieve the oxidative damage, Silk heat resistance. POD activity was significantly decreased under high temperature stress with exogenous SNP addition.