College of Life Sciences, Henan Normal University, Xinxiang, Henan 453007, China.
College of Life Sciences, Henan Normal University, Xinxiang, Henan 453007, China; State Key Laboratory of Cell Differentiation and Regulation, Henan International Joint Laboratory of Pulmonary Fibrosis, Henan center for outstanding overseas scientists of pulmonary fibrosis, College of Life Science, Institute of Biomedical Science, Henan Normal University, Xinxiang, Henan 453007, China.
Int J Biol Macromol. 2023 Jul 1;242(Pt 2):124833. doi: 10.1016/j.ijbiomac.2023.124833. Epub 2023 May 18.
Antimicrobial peptides (AMPs) are members of humoral immunity and particpate in resisting microbial invasion. In this study, an AMP gene hepcidin was obtained from the oriental loach Misgurnus anguillicaudatus and named Ma-Hep. This Ma-Hep encodes a peptide of 90 amino acids, with a predicted active peptide segment (Ma-sHep) of 25 amino acids at C terminus. Stimulation by a bacterial pathogen Aeromonas hydrophila resulted in significant up-regulation of Ma-Hep transcripts in loach midgut, head kidney, and gill. Ma-Hep and Ma-sHep proteins were expressed in Pichia pastoris and their antibacterial activity was examined. Results showed that Ma-sHep possessed stronger antibacterial activity against various Gram-positive and Gram-negative bacteria, compared to Ma-Hep. Scanning electron microscopy showed that Ma-sHep might kill bacteria by destroying bacterial cell membranes. Moreover, we found that Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila and facilitated the bacterial phagocytosis and clearance in loach. Histopathological analysis indicated Ma-sHep could protect liver and gut of loach from bacterial infection. Ma-sHep has high thermal stability and PH stability, which is conducive to further feed addition. Feed supplemented with Ma-sHep expressing yeast improved the intestinal flora of loach by increasing the dominant bacteria and decreasing the harmful bacteria. Feed supplemented with Ma-sHep expressing yeast also regulated the expression of inflammatory related factors in various tissues of loach and reduced the mortality of loach upon bacterial infection. These findings show that the antibacterial peptide Ma-sHep is involved in the antibacterial defense of loach and can be used as a candidate for new antimicrobial agents in aquaculture.
抗菌肽 (AMPs) 是体液免疫的成员，参与抵抗微生物入侵。本研究从泥鳅 (Misgurnus anguillicaudatus) 中获得了一个 AMP 基因 hepcidin，并将其命名为 Ma-Hep。该 Ma-Hep 编码一个 90 个氨基酸的肽，C 末端有一个预测的活性肽段 (Ma-sHep)，由 25 个氨基酸组成。细菌病原体嗜水气单胞菌刺激后，泥鳅中肠、头肾和鳃中 Ma-Hep 转录本显著上调。Ma-Hep 和 Ma-sHep 蛋白在毕赤酵母中表达，并检测了它们的抗菌活性。结果表明，与 Ma-Hep 相比，Ma-sHep 对各种革兰氏阳性和革兰氏阴性菌具有更强的抗菌活性。扫描电子显微镜显示，Ma-sHep 可能通过破坏细菌细胞膜来杀死细菌。此外，我们发现 Ma-sHep 对嗜水气单胞菌诱导的血细胞凋亡具有抑制作用，并促进泥鳅中细菌的吞噬和清除。组织病理学分析表明，Ma-sHep 可以保护泥鳅的肝脏和肠道免受细菌感染。Ma-sHep 具有较高的热稳定性和 PH 稳定性，有利于进一步添加到饲料中。添加表达 Ma-sHep 的酵母的饲料通过增加优势菌和减少有害菌来改善泥鳅的肠道菌群。添加表达 Ma-sHep 的酵母的饲料还调节了泥鳅各组织中炎症相关因子的表达，降低了泥鳅在细菌感染时的死亡率。这些发现表明，抗菌肽 Ma-sHep 参与了泥鳅的抗菌防御，可以作为水产养殖中新型抗菌剂的候选物。
