Fig. 5: Natively-expressed Zorya II halts phage infection by mediating population-wide immunity.
From: Modularity of Zorya defense systems during phage inhibition
a The anti-phage activity of Zorya I and Zorya II under the control of their native promoter was evaluated by calculation of their fold protection against a suite of newly isolated environmental coliphages. As a control, ɸAlma, ɸMav, ɸT7, and ɸCS16F were included. Fold protection was calculated by dividing the value of efficiency of plating (EOP) for strains expressing Zorya I or Zorya II by the EOP value of a strain carrying the empty vector (pSUPROM), when infected with phages as shown in panel (a). b Efficiency of plating (EOP) measurement for E. coli MT56 carrying the empty vector (VC, pSUPROM) or the same vector carrying Zorya II, ZorAE, ZorBE, Zor AB II or ZorE under the control of their native promoter, when infected with ɸphAvM. Points show mean ± SEM (n = 3 biological replicates). Statistical significance was calculated with Graphpad applying a one-way ANOVA with Dunnett’s multiple comparison test. No significance was detected, unless indicated (*p ≤ 0.05). For VC vs Zorya II comparison, p-value = <0.0001. c–h E. coli MT56 carrying the empty vector (VC, pSUPROM) or the same vector expressing Zorya II under its native promoter was infected with ɸphAvM at MOI 5 or 0.05. The c, f, titer (PFU/mL), d, g cell counts (CFU/mL) and e, h, and g, the growth rate (OD600nm) of each culture was measured at several time points, as shown in panels (c–h), over the course of 12 h post-infection. For panels c–h, points show mean ± SEM (n = 3 biological replicates). Statistical significance was calculated with Graphpad applying a two-way ANOVA comparison test. No significance was detected, unless indicated (*p ≤ 0.05). c The p-values for the VC vs Zorya II comparisons are as follows: for the 3-h time point, p = 0.0066; for the 6-h time point, p = 0.045; for the 9-h time point, p = 0.049; and for the 12-h time point, p = 0.0006. f The p-values for the VC vs Zorya II comparisons are as follows: for the 3-h time point, p = 0.013; for the 6-h time point, p = 0.019; for the 9-h time point, p = 0.007; and for the 12-h time point, p = 0.0028.
