State Key Laboratory of Marine Environmental Science, College of Oceanography and Environmental Science, Xiamen University, Xiamen 361005, Fujian, PR China.
Fish Shellfish Immunol. 2010 May-Jun;28(5-6):862-71. doi: 10.1016/j.fsi.2010.02.008. Epub 2010 Feb 11.
Recent studies revealed that antioxidant enzymes play important roles in antioxidant responses caused by metabolic process or pathogen invasion. Catalase is one of these key enzymes which has been characterized and highly conserved from invertebrates to vertebrates. In the present study, a full-length cDNA sequence of catalase was cloned from the hemocyte suppression subtractive hybridization library of the crab Scylla paramamosain. The Sp-catalase (Sp-CAT) cDNA sequence contained 2551bp with an open reading frame of 1551bp encoding 517 amino acid residues. The conserved catalytic active residues His-71, Asn-144 and Tyr-354 were predicted in the amino acid sequence of Sp-CAT. The deduced Sp-CAT protein had a calculated molecular mass of 59 kDa with an estimated isoelectric point of 6.4. Multiple alignment analysis revealed that the deduced amino acid sequence of Sp-CAT shared high identity (75.4%) with those of other species. The Sp-CAT mRNA transcripts were demonstrated in multiple tissues of normal S. paramamosain. After LPS challenge, the expression level of Sp-CAT gene was increased significantly in hemocyte at 3 and 6 h, and in hepatopancreas at 6 h, respectively, determined by quantitative real-time PCR. Furthermore, the activities of CAT and SOD were also measured in different tissues and serum after LPS challenge. The CAT activity was significantly increased at 3, 6, 24 and 48 h in hemocyte lysate, at 3 h in serum, and at 24 and 48 h in hepatopancreas after LPS challenge. In addition, the SOD activity was significantly induced at 3 and 6 h in hemocyte lysate, 3 and 12 h in serum, 12 and 48 h in hepatopancreas post LPS stimulation, indicating a tissue and time-dependent antioxidant response in the crab. Taken together, these data demonstrated that a strong antioxidant response occurred in the LPS-challenged crab, which might be involved in the protection of host against microbial infections.
最近的研究表明，抗氧化酶在代谢过程或病原体入侵引起的抗氧化反应中发挥重要作用。过氧化氢酶是这些关键酶之一，它在从无脊椎动物到脊椎动物的物种中都得到了很好的鉴定和高度保守。本研究从锯缘青蟹血细胞抑制消减杂交文库中克隆到过氧化氢酶的全长 cDNA 序列。Sp-catalase（Sp-CAT）cDNA 序列全长 2551bp，开放阅读框 1551bp，编码 517 个氨基酸残基。在 Sp-CAT 的氨基酸序列中预测到保守的催化活性残基 His-71、Asn-144 和 Tyr-354。推导出的 Sp-CAT 蛋白的计算分子量为 59 kDa，估计等电点为 6.4。多重比对分析表明，Sp-CAT 的推导氨基酸序列与其他物种的序列具有高度同源性（75.4%）。通过定量实时 PCR 证实 Sp-CATmRNA 转录本在正常锯缘青蟹的多种组织中表达。在 LPS 刺激后，Sp-CAT 基因在 3 和 6 h 的血细胞中以及在 6 h 的肝胰腺中的表达水平显著增加。此外，还在 LPS 刺激后不同组织和血清中测量了 CAT 和 SOD 的活性。在 LPS 刺激后，血细胞裂解物中的 CAT 活性在 3、6、24 和 48 h 时显著增加，在血清中在 3 h 时显著增加，在肝胰腺中在 24 和 48 h 时显著增加。此外，在 LPS 刺激后 3 和 6 h 的血细胞裂解物中、3 和 12 h 的血清中、12 和 48 h 的肝胰腺中，SOD 活性显著诱导，表明在 LPS 刺激的蟹中存在组织和时间依赖性的抗氧化反应。综上所述，这些数据表明，在 LPS 刺激的蟹中发生了强烈的抗氧化反应，这可能参与了宿主对抗微生物感染的保护。
