FIG. 3.

Detection of protease secretion by B. pseudomallei strains on 3% skim milk agar. (A) Plasmid disruption of gspE and gspN resulted in strains that were completely or partially defective in protease secretion, respectively. The strains were grown on 3% skim milk agar plates containing tetracycline, and protease activity is indicated by a dark zone of clearing around the isolated colonies. (B) Complementation of the gspC::Tn5-OT182 mutation in DD214 by supplying gspC in trans on pIR2. The strains were grown on 3% skim milk agar plates containing trimethoprim, and protease activity is indicated by a light zone of clearing around the isolated colonies.