Vaseeharan Baskaralingam, Shanthi Sathappan, Chen Jiann-Chu, Espiñeira Montserrat
Department of Animal Health and Management, Alagappa University, Karaikudi 630 003, Tamil Nadu, India.
Department of Aquaculture, College of Life Sciences, National Taiwan Ocean University, 202, Keelung, Taiwan, ROC.
Results Immunol. 2012 Feb 14;2:35-43. doi: 10.1016/j.rinim.2012.02.001. eCollection 2012.
Penaeidins are members of a special family of antimicrobial peptide existing in penaeid shrimp and play an important role in the immunological defense of shrimp. Here, we report a penaeidin sequence cloned from the Indian white shrimp Fenneropenaus indicus (Fein-Penaeidin). The Fein-Penaeidin open reading frame encodes a 77 amino acid peptide including a 19 amino acid signal peptide. The deduced amino acid sequences of Fein-Penaeidin include a proline rich N-terminal domain and a carboxyl-domain that contains six cysteine residues. Structural analysis revealed an alpha-helix in its secondary structure and the predicted 3D structure indicated two-disulphide bridges in the alpha-helix. Phylogenetic analysis and sequence comparison with other known peaneidin suggest the gene shows high similarity to that of penaeidin from Peneaus monodon (95%), F. indicus (80%) and Fenneropenaeus chinensis (74%). Fein-Penaeidin was examined in normal and microbial challenged shrimp and was found to be constitutively expressed in haemocytes, Heart, gills, muscles, intestine, hepatopancreas and eyestalk. Bacterial challenge resulted in mRNA up-regulation, inducing expression at 6 h post injection indicating the penaeidin involved in the innate immunity.
对虾抗菌肽是存在于对虾中的一类特殊抗菌肽家族成员，在对虾的免疫防御中发挥重要作用。在此，我们报道了从印度白对虾（Fenneropenaus indicus）克隆的一种对虾抗菌肽序列（Fein - 对虾抗菌肽）。Fein - 对虾抗菌肽的开放阅读框编码一个77个氨基酸的肽段，包括一个19个氨基酸的信号肽。Fein - 对虾抗菌肽推导的氨基酸序列包括一个富含脯氨酸的N端结构域和一个含有六个半胱氨酸残基的羧基结构域。结构分析显示其二级结构中有一个α - 螺旋，预测的三维结构表明在α - 螺旋中有两个二硫键。系统发育分析以及与其他已知对虾抗菌肽的序列比较表明，该基因与斑节对虾（Peneaus monodon）的对虾抗菌肽基因相似度很高（95%），与印度白对虾自身的相似度为80%，与中国对虾（Fenneropenaeus chinensis）的相似度为74%。在正常和受到微生物攻击的对虾中检测了Fein - 对虾抗菌肽，发现它在血细胞、心脏、鳃、肌肉、肠道、肝胰腺和眼柄中组成性表达。细菌攻击导致mRNA上调，在注射后6小时诱导表达，表明对虾抗菌肽参与先天免疫。
