关键词: 副溶血性弧菌, 噬菌体, 裂解酶, 生物抗菌剂, 食品安全

Abstract: [Background] Vibrio parahaemolyticus is one of the common zoonotic pathogens. Due to the increasing number of multi-drug resistant strains and people's concern about food safety, it is of great significance to develop biological antimicrobials that act differently from traditional antimicrobials. [Objective] To study the in vitro cleavage effect of bacteriophage vB_VpP_1 lysin on V. parahaemolyticus. [Methods] The gp32 gene fragment of bacteriophage vB_VpP_1 was identified as lysin gene according to the results of whole genome sequencing and functional analysis. The amino acid sequence composition and structure of gp32 were analyzed by Expasy and other tools. Primers were designed using Primer 5.0 software and cloned into pET-28a(+) vector for prokaryotic expression. The purified lysin was treated on host bacteria and EDTA treated host bacteria, and the activity of lysin was measured. [Results] The tertiary structure of vB_VpP_1 lysin was a spherical hydrophilic protein, which was predicted to contain two catalytic domains, and was consistent with the basic characteristics of Gram-negative phage lysin. There was no transmembrane region and signal peptide. The purified bacteriophage vB_VpP_1 had a lysin activity of about 1487±182 U/mg, which showed a strong ability to lyse V. parahaemolyticus whose cell wall was damaged by EDTA, but could not effectively lyse V. parahaemolyticus whose cell wall was intact. [Conclusion] The prokaryotic expression vector of bacteriophage vB_VpP_1 lysin was successfully constructed, and the expressed and purified lysin could lyse V. parahaemolyticus with damaged cell wall.

Key words: Vibrio parahaemolyticus, bacteriophage, lysin, biocontrol agents, food safety