FIG 4.

EsrF and flhB promotes O157 motility. (A) Representative images of swimming motility of O157 WT, ΔesrF, ΔesrF+PesrF, ΔflhB, ΔflhB+PflhB, and ΔesrF ΔflhB strains. All strains were observed after 12 h of growth in semisolid LB medium at 25°C. (B) Representative TEM images of O157 WT, ΔesrF, ΔesrF+PesrF, ΔflhB, ΔflhB+PflhB, and ΔesrF ΔflhB strains. Scale bar, 500 nm. (C) qRT-PCR of the expression of flhD, flhC, fliA, and fliC in WT, ΔflhB, and ΔflhB+PflhB strains. The data are presented as means ± the SD (n = 3; ns, no significance; *, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001). All P values were calculated using a Student t test.