FIG. 2.

Visualization of virulence plasmid transfer from Salmonella to E. coli. (A) Pulsed-field gel stained with ethidium bromide. (B) Southern hybridization of the pulsed-field gel with a probe specific to the kanamycin resistance gene of MudJ. The virulence plasmid is present in the donor Salmonella strain, BA1541 (spv::MudJ), and the three transconjugants but is not present in the recipient E. coli strain, BA769. Pulsed-field gel electrophoresis and Southern blotting were performed as described in the legend to Fig. 1.