Figure 3. Bacterial lysates from BL-21 E. coli transformed with pTrc-BME constructs and used as inoculums in mouse alveolar type II epithelial cells invasion assays.

Bacteria were grown to log phase in LB broth supplemented with antibiotic followed by the addition or exclusion of IPTG and 4 hours of continued incubation. Bacterial lysates were diluted with SDS loading buffer, incubated at 95°C for 5 minutes and electrophoresed in a 12.5% SDS-PAGE gel. Lanes 1, 3, 5, 7, 9, lysate from BL-21 cells stimulated with IPTG and overexpressing OmpW, BtuB, Omp22, cell surface protein, and FlgK (arrows), respectively. Lanes 2, 4, 6, 8, 10, lysates from non-stimulated BL-21 cells containing protein expression constructs for OmpW, BtuB, Omp22, cell surface protein, and FlgK.