Fig. S1.
Effects of BtrA on growth and on protein expression and secretion. (A) Growth in baffled 250-mL Erlenmeyer flasks containing Stainer–Scholte medium incubated at 37 °C with shaking. Doubling times, calculated from cfu on Bordet–Gengou agar, were 1.89 ± 0.17 h for RB50 and 6.78 ± 1.35 h for the ∆btrA derivative. Each point on the curve is an average from triplicate experiments. Error bars represent ±SEM. B. bronchiseptica RB50 is represented with circles and ∆btrA with squares. (B–D) Protein expression and secretion from midlog phase deletion mutants (B), pbtrA complemented strains (C), or pbtrS complemented strains (D) grown in Stainer–Scholte medium. (Top) Coomassie brilliant blue-stained SDS/PAGE showing pellet and culture supernatant fraction profiles. (Bottom) Immunoblot analysis of culture supernatant or pellet fractions from the indicated strains. Blots were probed with antisera against CyaA, FhaB, Prn, and Bsp22. Asterisks indicate T3SSBsc secretion substrates.