FIG. 2.

Peptide wrwycr inhibits excision of Salmonella prophage. (A) Chloroform lysates of LT2 P22 lysogen cultures treated with MMC, peptide, or both (as indicated on the left). (B) Chloroform lysates of wild-type LT2 cultures treated with MMC or peptide (as indicated). Lysates were serially diluted 10-fold and plated onto a lawn of MA8508, an LT2-derived strain cured of three of its four naturally occurring prophages and deleted for a large fraction of the fourth prophage (Gifsy-1, Gifsy-2, Fels-1, and Fels-2). Two microliters of each lysate, either undiluted or subsequent 10-fold dilutions, was spotted onto the bacterial lawns. These plates are representative of four to eight independent induction experiments.