FIG. 3.

In vitro phage delivery of lethal agents to E. coli. A CFU assay was performed to evaluate the effects of the phage-delivered lethal agents on the killing of E. coli ER2738. Target cells were grown to mid-exponential phase (OD₆₀₀ of 0.8) in LB broth containing tetracycline and diluted to approximately 10⁶ CFU/ml in LB broth containing 1 mM IPTG. An aliquot of cells (10⁵ CFU, 100 μl) was incubated at 37°C with an equal volume of phage lysate (8 × 10⁹ PFU/ml). Control experiments were carried out in the absence of phage lysate. Treatments were as follows: (first bar) cells plus buffer, (second bar) cells plus Gef phagemid lysate, and (third bar) cells plus ChpBK phagemid lysate. Treatments reflect viable cell counts following 30 min of incubation at 37°C. Viable counts were determined following dilution and plating of the infection on LB plates containing 1 mM IPTG. The figure is representative of at least two experiments with each infection performed in triplicate. All values are means ± standard deviation.