Characterisation of Vibrio parahaemolyticus phage lyase LysF23s2 and LysH256D1
Vibrio parahaemolyticus poses a great threat to food safety,while the misuse of antibiotics has led to the increase of drug-resistant bacteria.In this paper,two Vibrio parahaemolyticus phage lytic enzymes were expressed using the BL21 and T7 expression systems at 16 ℃ and 37 ℃.After successful expression and purification of the lyase enzyme,the lyase enzyme was analyzed for its lysing ability and thermal stability against Vibrio parahaemolytic-us,as well as the effect of metal ions on its activity.The results showed that LysF23s2 and LysH256D1 were ex-pressed at higher concentrations when induced by low temperature in BL21.The lysis rates of LysF23s2 and Ly-sH256D1 reached 75.24%and 71%,respectively,against the host bacteria at a concentration of 10 μmol/L.The lysis rates of LysF23s2 and LysH256D1 were reduced to 10%and 8.82%after being incubated at 90 ℃ for 30 min,but still maintained some activity.The activity of LysF23s2 and LysH256D1 was inhibited by Na2+,Ca2+and Zn2+,In this study,the phage lytic enzymes LysF23s2 and LysH256D1,which are capable of lysing Vibrio parahae-molyticus,were expressed in the E.coli system,and two lytic enzymes with good lysing activity and heat resistance were obtained.