Ali Wajid, Chen Ying, Wang Zhuoyu, Sun Minmin, Song Yongkang, Guo Xiaodan, Wang Xiangyuan, He Yan, Qi Jie
Key Laboratory of Marine Genetics and Breeding, Ministry of Education/ Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution, Ocean University of China, Qingdao, 266003, Shandong, China.
The University of New South Wales, Kensington NSW, 2033, Australia.
Fish Shellfish Immunol. 2025 Jul;162:110310. doi: 10.1016/j.fsi.2025.110310. Epub 2025 Apr 3.
Amicrobial peptides are crucial components of immune system, acting as the first line of defense against microbial invasion. This study investigated the antimicrobial activity of TroLEAP2 like-27, a novel 27-amino acid peptide derived from golden pompano (Trachinotus ovatus), against Gram-positive Lactococcus garvieae and Staphylococcus epidermidis, and Gram-negative Vibrio alginolyticus and Vibrio harveyi. The 3D structure and helical wheel presentation of TroLEAP2 like-27 were consistent with typical AMP features. The hydrophobic ratio of TroLEAP2 like-27 was 47 %, and its α-helical structure suggested strong antimicrobial potential. The expression levels of the TroLEAP2 like gene in the liver and intestines tissues of T. ovatus were significantly upregulated following infection with L. garvieae and V. harveyi. The peptide induced bacterial agglutination in the presence of Ca and exhibited bactericidal activity with a MIC of 60 μM. Transmission electron microscopy (TEM) revealed structural damage to bacterial membranes, while membrane permeability assays showed dose-dependent disruption and depolarization in all tested strains. Additionally, TroLEAP2 like-27 exhibited a potent capacity to interact with and degrade genomic DNA of all tested bacteria. The peptide treatment significantly reduced bacterial loads in the gill, liver, and intestinal tissues of the fish, with histological analysis revealing a remarkable protective effect on the tissues. Furthermore, fish treated with TroLEAP2 like-27 exhibited improved survival rates following bacterial infection. These findings suggest that TroLEAP2 like-27 is a promising antimicrobial peptide with potential therapeutic applications.
抗菌肽是免疫系统的关键组成部分，作为抵御微生物入侵的第一道防线。本研究调查了一种源自卵形鲳鲹（Trachinotus ovatus）的新型27氨基酸肽TroLEAP2 like-27对革兰氏阳性加氏乳球菌和表皮葡萄球菌以及革兰氏阴性溶藻弧菌和哈维氏弧菌的抗菌活性。TroLEAP2 like-27的三维结构和螺旋轮展示与典型的抗菌肽特征一致。TroLEAP2 like-27的疏水率为47%，其α-螺旋结构表明具有强大的抗菌潜力。卵形鲳鲹肝脏和肠道组织中TroLEAP2 like基因的表达水平在感染加氏乳球菌和哈维氏弧菌后显著上调。该肽在有钙存在的情况下诱导细菌凝集，并表现出杀菌活性，最低抑菌浓度为60μM。透射电子显微镜（TEM）显示细菌膜结构受损，而膜通透性测定表明所有测试菌株均有剂量依赖性的破坏和去极化。此外，TroLEAP2 like-27表现出与所有测试细菌的基因组DNA相互作用并降解的强大能力。肽处理显著降低了鱼鳃、肝脏和肠道组织中的细菌载量，组织学分析显示对组织有显著的保护作用。此外，用TroLEAP2 like-27处理的鱼在细菌感染后存活率提高。这些发现表明TroLEAP2 like-27是一种有前途的抗菌肽，具有潜在的治疗应用。
