Fig. 6

Lytic activity assay of the phage S10 lysis proteins. A E. coli BL21 carrying recombinant plasmid (pCold-lysin1, pCold-holin, pCold-lysin2) was induced with 0.5 mM IPTG at 16 °C for 16 h. Colony counts were performed at 16 h to test the intracellular lytic activities of lysin1, holin and lysin2. E. coli BL21 carrying the pCold-TF plasmid was used as the control. B S. enterica 35 was treated with lysin1, holin, lysin2 or their mixture, and the titers were assessed at 0.5 h and 2 h to determine the extracellular antibacterial activities of protein. TF protein was used as the control. C The effect of lysis proteins against S. enterica 35 with EDTA treatment at 0.5 h and 2 h. TF protein was used as the control. D The antibacterial activities of lysis proteins against E. coli BL21 without EDTA treatment at 0.5 h and 2 h. All assays were repeated three times, and the data are expressed as the mean ± SD