Schematic and PCR analysis of parent and recombinant endolysin-deficient phage P954. Alignment of primers to the (a) parent phage DNA template and (b) recombinant phage DNA template, in which the cat gene had been inserted into the endolysin gene (LYS). (c) Endolysin forward and reverse primers yield a 750-bp PCR product of the parent phage P954 and 2400-bp product of the recombinant phage P954. (d) The holin forward primer and endolysin reverse primer yield a 1000-bp PCR product with parent phage P954 and 2650-bp product of the recombinant phage P954. Both PCR panels include lane 1: PCR buffer (negative control); lane 2: parent phage P954 lysogen B7, lane 3: molecular weight marker (λ/HindIII-EcoRI); lane 4: recombinant phage P954 lysogen H10.