Abstract:Vibrio parahaemolyticus phages were isolated and purified from fish market effluent. One particular phage, phage vB_VpP_AC2 (AC2), was Vibrio parahaemolyticus phages were isolated and purified from fish market effluent. One particular phage, phage vB_VpP_AC2 (AC2), was isolated, genetically sequenced, and subjected to partial biological analysis to investigate its potential as a biocontrol agent against V. parahaemolyticus. The viral plaques of phage AC2 were transparent with clear boundaries; the diameter of the transparent parts was approximately 1.12 mm, with no visible halos. The genome sequence of phage AC2 was 44 270 bp long, with a guanine-cytosine content of 49.30%. In all, 55 putative open reading frames were predicted, and 37 (67.27%) of these were similar to genes encoding proteins of known function, including a holin-like protein (AC2_gp43, UTQ72417.1) that was first characterized in the genus Maculvirus. The results of protein-protein interaction network and terminase phylogenetic analyses showed that phage AC2 belongs to the family Autograohiviridae and genus Maculvirus. The Vibrio phage vB_VpaP_MGD1 shared the highest Average Nucleotide Identity based on BLAST (ANIb) value with AC2, at 95.62%. Biological analysis revealed that phage AC2 lysed 30.77% of the tested strains, with optimal multiplicities of infection of 0.001~0.1. Its one-step growth curve showed that its latent and lytic phases were 20 and 35 min long, respectively, with a burst size of 143 pfu/cell. In summary, the isolation and identification of phage AC2 provided useful information on its functional proteins, indicating that it is a valuable phage for aquatic food safety.
