Comparison of TU-counting and qPhage.
(A) Representation of phage genome and relative location of the cloning site and two sets of primers used. Primer set #1 targets the TetR gene and was used for quantification with real-time PCR; primer set #2 flanks the insert coding for the peptide displayed in pIII, and served for large-scale sequencing (B and C, respectively). TU-counting and qPhage titration output [determined by cycle-thresholds (Ct)]; note the limited quantification range for TU-counting relative to qPhage. Comparative results of TU-counting and qPhage titration of Fd-tet (D) and RGD-4C phage (E) are shown. Asterisk indicates that the high bacterial density prevented accurate TU determination.