Fig. 4

Flow cytometry analysis, in the FACS format, of surface modified and negative control recombinant B. subtilis cells. a Bs-NC1 strain as a negative control, b Bs-SpA strain. Vertical line denotes the number of cells and horizontal line is the strength of fluorescence. M1 shows a gate to detect only cells that fall in a positive area. All the cells outside this gate are ignored as a background. The cells that are located in M1 region represent the cell that display the SpA protein on their surface