硫化物胁迫对凡纳滨对虾血细胞抗氧化酶基因表达的影响

Effects of Sulfide Stress on Expressions of Antioxidant Enzymes in Litopenaeus vannamei Haemocytes

硫化物是水产养殖过程中常见的水体污染物之一,为探讨抗氧化酶在凡纳滨对虾Litopenaeus vannamei血细胞抗硫化物胁迫中的作用,以不同浓度(0 mg·L^(-1)和2.0 mg·L^(-1))的硫化物对凡纳滨对虾进行胁迫,于胁迫后的0 h、6 h、12 h、24 h和48 h取血淋巴,测定血细胞中铜锌超氧化物歧化酶(Cu,Zn-SOD)、锰超氧化物歧化酶(Mn-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GPx)和硫氧还蛋白(TRx)基因表达量的变化。结果显示,Cu,Zn-SOD和TRx的表达量在胁迫的6~24 h显著上升,在48 h时恢复至对照组水平;Mn-SOD和GPx的表达量在胁迫的6~48 h均显著上调;CAT表达水平在胁迫的12 h开始有显著提高。这些结果表明凡纳滨对虾血细胞抗氧化相关基因的表达均被诱导上调,以进行防御;Cu,Zn-SOD、Mn-SOD、GPx和TRx均对硫化物胁迫敏感,在胁迫前期发挥作用,CAT主要在胁迫后期发挥作用。

Sulfide is one of the common water pollutants in aquaculture. To investigate the role of antioxidant enzymes in anti-sulfide defense of shrimp haemoeytes, gene expression levels of copper, ziue-superoxide dismutase （ Cu, Zu-SOD ） , manganese-superoxide dismutase （Mn-SOD） , catalase （CAT）, glutathion peroxidase （GPx） and thioredoxin （TRx） were determined in haemocytes of the white shrimp （Litopenaeus vannamei） exposure to sulfide （0 mg · L-1 and 2. 0 mg·L-1 ） for 0 h, 6 h, 12 h, 24 h and 48 h. The results showed that expression levels of Cu, Zn-SOD and TRx significantly increased after 6 - 24 h exposure, and reduced to the control levels at 48 h. Mn-SOD and GPx mRNA expression levels were up-regu- lated after 6 ~48 h exposure. CAT expression level began to increase after 12 h exposure. These results indicated that the mRNA expressions of antioxidant enzymes were induced to protect the haemocytes against sulfide stress. Cu, Zn-SOD, Mn- SOD, GPx and TRx displayed high sensitivity to sulfide stress, and might play the dominant role at the initial stage of sulfide stress, whereas CAT mainly worked at the later period.