中华乌塘鳢NK-lysin基因的克隆鉴定、表达分析及抗菌功能研究

Molecular Characterization,Expression and Antibacterial Activity of NK-lysin in Bostrychus sinensis

NK-lysin是一种具有广谱抗菌活性和免疫调节功能的阳离子抗菌肽。通过分子克隆方法获得中华乌塘鳢的NK-lysin基因(BsNKL)cDNA序列。BsNKL编码152个氨基酸,包含1个信号肽、1个SapB结构域和6个保守半胱氨酸残基。基因表达分析表明,BsNKL在主要器官组织中均有表达,副溶血弧菌感染能够引起BsNKL表达量在脾脏、头肾和鳃中发生显著变化。中华乌塘鳢BsNKL抗菌肽对金黄色葡萄球菌、大肠杆菌、副溶血弧菌和哈维氏弧菌等4种细菌均具有较好的抑菌活性。腹腔注射BsNKL能够为细菌感染的中华乌塘鳢提供有效的免疫保护并显著提高其存活率。综上所述,BsNKL在中华乌塘鳢抗细菌感染天然免疫应答方面发挥重要作用。

NK-lysin is a cationic antimicrobial peptide with a broad spectrum of antibacterial activities and the function of immune regulation.In this study,the cDNA sequence of the NK-lysin gene(BsNKL)was obtained from Bostrychus sinensis.BsNKL encodes 152 amino acids,including a signal peptide,a SapB domain and six conserved cysteine residues.Gene expression analyses revealed that BsNKL is constitutively expressed in major organs of B.sinensis,and could be significantly induced in the spleen,head kidney and gills after Vibrio parahaemolyticus infection.The BsNKL peptide exhibited antibacterial activity against Staphylococcus aureus,Escherichia coli,V.parahaemolyticus and V.harveyi.The intraperitoneal injection of synthetic BsNKL peptide could significantly improve the survival rate of B.sinensis against V.parahaemolyticus infection.These results indicated that BsNKL plays an important role in innate immune defense against bacterial infection in B.sinensis.