FIG. 1.

Expression of type III secretion genes in Tn insertional mutants of mucA. PAK, PAKexsA, and mucA mutants A44 and A61 harboring pHW0006 containing exoT::lacZ (A), pHW0032 containing exsA::lacZ (B), pHW0005 containing exoS::lacZ(C), or pHW0024 containing pscN::lacZ (D) were tested for β-galactosidase activities. Bacteria were grown in LB (white bars) or LB containing 5 mM EGTA (black bars) to an OD₆₀₀ of 1 to 2 before β-galactosidase assays. Each assay was done in triplicate, and the error bars indicate standard deviations.