The relative number of E. coli 40 min (A) and 3 h (B) after the injection of recombinant proPO fragments. The following were mixed with E. coli and injected separately: Tris-HCl (buffer control), proPO-ppA, proPO-casp1, proPO-casp2 and GFP (protein control). The relative number of E. coli in units of CFU/ml was calculated as the number for the specific fragments compared with the number for Tris-HCl. The results were analyzed using one-way ANOVA. * P<0.05, ** P<0.01, *** P<0.001 indicate a significant differences between the treatment and the Tris-HCl control. All experiments were repeated three times (N = 3). Each bar represents the mean ± SEM.