Department of Marine Life Sciences, College of Ocean Sciences, Jeju National University, Jeju Special Self-Governing Province 690-756, Republic of Korea.
Fish Shellfish Immunol. 2010 Feb;28(2):261-6. doi: 10.1016/j.fsi.2009.11.005. Epub 2009 Nov 14.
Gene-encoded antimicrobial peptides (AMPs) serve a major role in host defense systems against pathogens. In this study, cDNA of a new mollusk defensin was identified from a normalized cDNA library constructed from whole tissues of disk abalone. Abalone defensin peptide (pro-defensin) has a 198-bp coding sequence comprised of a putative 66 amino acids with a mature defensin consisting of 48 amino acid residues. The presence of an invertebrate defensin family domain, an arrangement of six cysteine residues and their disulfide linkage in C(1)-C(4), C(2)-C(5) and C(3)-C(6) form, an alpha helix in three-dimensional structure and a phylogenetic relationship suggests that abalone defensin could be a new member of the invertebrate defensin family, and related to arthropod defensins. In non-stimulated abalone, defensin transcripts were constitutively expressed in all examined tissues including hemocytes, gills, mantle, muscle, digestive tract and hepatopancreas. It was observed that abalone defensin transcripts were significantly induced in hemocytes, gills and digestive tract at different time intervals after infection by pathogenic bacteria mixture containing Vibrio alginolyticus, Vibrio parahemolyticus and Lysteria monocytogenes. Our overall results suggest that disk abalone defensin could be involved in the immune response reactions as a host defense against pathogenic bacteria.
基因编码的抗菌肽 (AMPs) 在宿主防御系统对抗病原体方面发挥着重要作用。在这项研究中，从盘鲍整体组织构建的标准化 cDNA 文库中鉴定出一种新的贝类防御素 cDNA。鲍防御素肽（原防御素）具有 198bp 的编码序列，由 66 个氨基酸组成，成熟防御素由 48 个氨基酸残基组成。该防御素具有无脊椎动物防御素家族结构域、6 个半胱氨酸残基的排列以及在 C(1)-C(4)、C(2)-C(5) 和 C(3)-C(6) 形成的二硫键连接、三维结构中的α螺旋和系统发育关系表明，鲍防御素可能是无脊椎动物防御素家族的一个新成员，与节肢动物防御素有亲缘关系。在未受刺激的鲍中，防御素转录本在所有检测到的组织中均持续表达，包括血细胞、鳃、套膜、肌肉、消化道和肝胰腺。观察到在感染含有溶藻弧菌、副溶血弧菌和单核细胞增生李斯特菌的混合致病菌后不同时间间隔，血细胞、鳃和消化道中的鲍防御素转录本显著诱导。我们的总体结果表明，盘鲍防御素可能作为宿主防御系统的一部分参与免疫反应，以抵抗致病菌。
