镉对灵芝菌丝抗氧化系统的影响

研究了不同浓度镉(Cd) (0、10、50、100、200和400 μmol·L^-1)对灵芝菌丝抗氧化系统的影响.结果表明，随着Cd浓度增加，菌丝鲜质量、脯氨酸、总糖和还原糖含量逐渐下降，非蛋白巯基化合物（NPT）水平逐渐上升，当Cd浓度达到400 μmol·L^-1时，NPT含量急剧上升至对照组的6.7倍.在试验浓度范围内，灵芝菌丝体过氧化物酶（POD）、谷胱甘肽还原酶（GR）和过氧化氢酶（CAT）活性呈显先上升后下降的变化趋势，并均在Cd浓度为100 μmol·L^-1时达峰值；超氧化物歧化酶（SOD）和脂氧合酶（LOX）活性则随着Cd浓度的增加而逐渐上升，在Cd浓度为400 μmol·L^-1时达峰值.采用聚丙烯酰胺凝胶电泳分析Cd胁迫下灵芝菌丝抗氧化酶的同工酶谱发现，100～400 μmol·L^-1 Cd处理诱导出2条Mn-SOD型同工酶带；10～200 μmol·L^-1 浓度Cd上调组成型CAT、SOD、POD和LOX同工酶的表达强度；而400 μmol·L^-1 Cd的则显著抑制了POD同工酶的表达.

Effects of cadmium stress on the antioxidative system in Ganoderma lucidum mycelia

The study on the effects of different concentration (0, 10, 50, 100, 200 and 400 micromol x L(-1)) cadmium (Cd) on the antioxidative system in Ganoderma lucidum mycelia indicated that with increasing concentration of Cd, the fresh mass and the proline, total polysaccharides, and reduced polysaccharides contents of G. lucidum mycelia decreased, but non-protein thiol (NPT) content increased. At 400 micromol x L(-1) of Cd, the NPT content increased dramatically, being 5.7 times higher than control. Within the range of test Cd concentrations, the activities of CAT, GR and POD increased first and decreased then, with the peak at 100 micromol x L(-1) of Cd, while the activities of LOX and SOD increased with increasing Cd concentration, with the maximum at 400 micromol x L(-1) of Cd. Polyacrylamide gel electrophoresis analysis revealed that 100-400 micromol x L(-1) of Cd induced two additional isozymes bands of Mn-SOD, 10-200 micromol x L(-1) of Cd increased the intensity of constitutive isozymes of CAT, POD, SOD and LOX, while 400 micromol x L(-1) of Cd decreased the intensity of isozymes of POD significantly.