FIG. 4.
PFU per ml on C600 strains harboring recombinant plasmids with genes influencing phage propagation. White bars indicate strains with functional regulatory genes; black bars indicate control strains harboring genes with frameshift mutations. In C600 strains with functional CI and CII repressors, phage titers were reduced to below 1% (white bars missing). (A) Phage lysate from strain CB2851 had a titer of 7.5 × 104 phages (PFU/ml) on C600; the standard deviations for control strains were too low to be visible. (B) Phage lysate from strain TPE1874 had a titer of 1.5 × 106 (PFU/ml) on C600. Means and standard deviations are derived from three different experiments.