福建沿海米氏凯伦藻赤潮对皱纹盘鲍鳃组织抗氧化酶活性的影响研究

摘要

本文初步研究了在较低赤潮密度(低于107个/mL)下,一株米氏凯伦藻(Karenia mikimotoi)对皱纹盘鲍(Haliotis discus hannai)鳃内几种抗氧化酶,如超氧化物歧化酶(Superoxide dismutase, SOD)、过氧化氢酶(Catalase, CAT)、谷胱甘肽过氧化物酶(Glutathione peroxidase, GSH-Px)的毒性效应,以期分析米氏凯伦藻对鲍鱼生命活动可能的胁迫方式。研究表明,米氏凯伦藻对 SOD、CAT 酶活性均造成不利影响,并未对 GSH-Px 酶造成不利影响,其酶活性显著高于对照组。米氏凯伦藻对 SOD 酶活性的影响表现为“先诱导后抑制”效应,24 h 内,各处理组(0.1个/mL,0.5个/mL,1.0×104个/mL)中,酶活性急剧增高,分别是对照组的1.2,1.3,1.3倍,之后酶活性迅速下降,分别是对照组的77%,77%,73%。SOD 能够清除机体体内多余的自由基,其活力变化反映了机体抵制自由基损伤能力已受到明显抑制。此外,米氏凯伦藻处理组中, CAT 酶活性则处于“被抑制”状态,48 h 内酶活性持续下降,分别降低至对照组的58%,51%,37%。CAT 可以清除 SOD 歧化超氧阴离子自由基产生的 H2O2,其活力的下降也可能造成机体内过氧化物的累积及氧化损伤。结果表明,即使未达到较高赤潮密度(不超过107个/mL)时,米氏凯伦藻短时间内仍可对鲍鱼鳃内关键抗氧化酶活性造成显著抑制效应,这极有可能导致鲍鱼机体抗氧化系统遭受严重损伤。%To analyze the main threat of K. mikimotoi on the physiological features of abalones, we investigated the effects of K. mikimotoi on antioxidant enzymes of the abalone Haliotis discus hannai, including superoxide dismu-tase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). The results showed that exposure to a low cell concentration of K. mikimotoi (not exceeding 104 cell/mL) caused significantly adverse effects on the activity of SOD and CAT enzymes in the abalone gills, whereas no adverse effects were observed for the activity of GSH-Px. SOD activity showed an “induced and then inhibited” trend. Compared to the control group, K. mikimotoi increased SOD activities by 120%, 130%, and 130% during the first 24 h, respectively. Thereafter, K. mikimotoi caused sig-nificant declines in SOD activity of 77%, 77%, and 73% at 48 h. Moreover, compared to the control group, CAT activity was inhibited and declined continuously over 48 h, decreasing by 58%, 51%, and 37%. These results indi-cate that K. mikimotoi (not exceeding 104 cell/mL) can cause inhibitory effects on the activities of antioxidant en-zymes (SOD and CAT).We speculate that the occurrence of a K. mikimotoi bloom could cause oxidative damage to abalone organs during short-term exposure.