FIG. 6.

Broth growth appearance of E. coli and Y. pseudotuberculosis strains transformed with either pHMS1, pHMSXB, or both plasmids. After transformation and growth on CR plates, colonies were cultured in BHI broth for 2 days at 28°C. In the presence of both plasmids, E. coli and Y. pseudotuberculosis PTB51 have a growth pattern similar to that of Y. pestis, with flecks of bacterial growth on the walls and bottom of the tube but little turbidity. PTB55 shows only a few of these growth characteristics. This experiment was repeated three times with similar results.