柱状田头菇菌丝对镉胁迫的抗氧化响应

Anti-oxidative responses of Agrocybe aegerita mycelia to cadmium stress

研究了不同浓度Cd处理对柱状田头菇菌丝抗氧化酶及谷胱甘肽含量的影响.结果表明,在低浓度范围内随着Cd处理浓度的增加,菌丝抗氧化酶的活力上升,过氧化氢酶（CAT）与超氧化物歧化酶（SOD）的活性分别在Cd浓度为0.1和0.4 mmol·L^-1时达最大值;过氧化物酶（POD）、谷胱甘肽还原酶（GR）和脂氧合酶（LOX）的活性在Cd浓度为0.2 mmol·L^-1时达到峰值.而在高Cd浓度处理时,柱状田头菇菌丝抗氧化酶系（POD、CAT、SOD等）显著受到抑制.0.4～1.6 mmol·L^-1Cd处理可显著提高菌丝体内还原型谷胱甘肽（GSH）水平,却不影响氧化型谷胱甘肽（GSSG）含量.在整个试验过程中,均未检测到抗坏血酸及抗坏血酸过氧化物酶（APX）的活性.用聚丙烯酰胺凝胶电泳分析Cd胁迫下柱状田头菇菌丝抗氧化酶的同工酶谱发现,0.1～0.8 mmol·L^-1Cd处理可诱导过氧化物酶（POD）、酯酶（EST）和脂氧合酶（LOX）新同工酶的表达,提高组成型过氧化氢酶（CAT）、超氧化物歧化酶（SOD）同工酶的表达强度;1.6 mmol·L^-1Cd处理显著抑制POD、CAT、SOD等的表达.

This paper studied the effects of different concentration Cd on the anti-oxidative enzyme activities and glutathione content in Agrocybe aegerita cultivated in liquid medium. The results indicated that at low concentrations of Cd, the test enzyme activities increased with increasing Cd concentration, being the maximum at 0. 1 mmol·L^-1 for CAT, at 0. 2 mmol·L^-1 for POD, GR and LOX, and at 0. 4 mmol·L^-1 for SOD. At 1.6 mmol·L^-1 of Cd, the activities of POD, CAT and SOD were inhibited markedly. 0. 4-1.6 mmol·L^- 1 of Cd resulted in an increase of glutathione content, but glutathione disulfide content was less affected. The ascorbate acid content and APX activity were too low to be detectable. The PAGE analysis revealed that 0. 1-0. 8 mmol·L^-1 of Cd induced the additional isozyme bands of POD, EST and LOX, and increased the intensity of the constitutive isozymes of CAT and SOD. 1.6 mmol·L^-1 of Cd decreased the intensity of the isozymes of POD, CAT and SOD significantly.