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Background: Vibrio are the main pathogenic bacteria in aquaculture. The flagellin protein C (FlaC) of Vibrio alginolyticus has good immunogenicity and the prospect of potential application in a vaccine., Objectives: We aimed to evaluate the immunogenicity, protective immunity, and prokaryotic expression fermentation of V. alginolyticus FlaC protein for the vaccine in aquaculture., Material and Methods: A molecular cloning method was used to construct the expression strain of FlaC protein, and the protein was purified with Ni-affinity chromatography. Polyclonal antiserum was prepared via mice immunized with the FlaC protein. The Western blot and enzyme-linked immunosorbent assay (ELISA) were used to check the specificity and titre of the antiserum. ELISA and pull-down assay detected the interaction between FlaC protein antiserum and Vibrio . The immune protection function of FlaC protein was detected with mice actively immunized with FlaC protein and challenged by V. alginolyticus and V. parahaemolyticus . The optimal expression conditions for FlaC protein were detected using an L 9 (3 4 ) orthogonal design model., Results: The expression strain of FlaC protein was obtained successfully, and purified FlaC protein was prepared using a mice polyclonal antibody. The FlaC protein antiserum held a high specificity, and the titre was 13200. The antiserum directly interacted with V. alginolyticus and V. parahaemolyticus , and the FlaC protein demonstrated a significant immune protection function (50%) against V. alginolyticus infection and some immune protection function (41.66%) against V. parahaemolyticus . The optimal expression conditions for FlaC protein included a strain OD 600 value of 0.8, final isopropyl-β-d-thiogalactoside (IPTG) concentration of 0.1 mmol/L, an inducing time of 8 hours, and an inducing temperature of 28°C., Conclusions: This study showed that the FlaC protein possesses a significant immunogenicity and immune protection effect and obtained the optimal fermentation conditions. It is expected to be a potential vaccine against V. alginolyticus and V. parahaemolyticus ., (Copyright: © 2019 The Author(s); Published by National Institute of Genetic Engineering and Biotechnology.)

Antibacterial peptides are a family of host-defense peptides most of which are gene-encoded and produced by living organisms of all types. Antibacterial peptides are small molecular proteins with broad antimicrobial spectrum against bacteria, viruses, fungi and sometimes even as anticancer peptide. SMAP-29, a cathelicidin-like peptide derived from sheep myeloid, line alpha-helical Structure, exerts a powerful broad antimicrobial activity against different pathogens including Gram-positive and Gram-negative bacteria, fungi, viruses, parasites, spirochaetes, chlamydia and antiendotoxin activity, and particular antibacterial mechanism, rapidly to permeabilize membranes of susceptible organisms. This paper summarizes the lately research progress of SMAP-29 and Variants including the characteristics of structure, structure-activity relationships, mode of action, diverse biological functions, gene recombinant and expression. We put emphasis on the necessity of molecular design, and primary and secondary structure-based modification, to provides a strong foundation for further drug development and design of SMAP-29.