FIG. 6.
Increased excision of ST64B does not contribute to the phenotype of envelope instability of dam mutants. Protein extracts were prepared from culture supernatants of the following isogenic strains: SL1344, wild type; SV1610, dam; MD1104, Δ[ST64B]; MD1202, Δ[ST64B] dam; MA6247, Δ[Gifsy-1 Gifsy-2]; MD1203, Δ[Gifsy-1 Gifsy-2] dam; MA7551, Δ[ST64B Gifsy-1 Gifsy-2]; MD1201, Δ[ST64B Gifsy-1 Gifsy-2] dam; MA7891, Δ[ST64B Gifsy-1 Gifsy-2 SopEΦ]; and MD0200, Δ[ST64B Gifsy-1 Gifsy-2 SopEΦ] dam. Bacteria were grown overnight in LB medium at 37°C in static conditions. The amount loaded per lane corresponded to the same number of bacteria (2 × 109). The sizes of the prestained molecular weight markers are indicated in kilodaltons. Arrows highlight a prominent protein that is only observed in dam mutants carrying the ST64B prophage. The assay was repeated three times with similar results.