Characterization of DltA expression in mutants. Proteins from solubilized H. ducreyi (∼107 CFU/lane) were subjected to SDS-PAGE under nonreducing conditions and Western blotting with anti-rDltA (panel 1) and DIG-FN (panel 2). Lanes: 35000HP, H. ducreyi 35000HP parental strain; FX533dltA, 35000HP dltA::Kan; FX533+p1286, FX533 complemented in trans with pUNCH1286dltA; FX533+pLSKS, FX533 complemented in trans with the empty vector pLSKS; FX517dsrA, 35000HP dsrA::CAT; FX534dsrAdltA, 35000HP dltA::Kan dsrA::CAT; FX534+p1286, FX534 complemented in trans with pUNCH1286dltA; FX534+pLSKS, FX534 complemented in trans with the empty vector pLSKS; H. flu+p1286, H. influenzae strain Rd containing pUNCH1286dltA; H. flu+pLSKS, H. influenzae strain Rd containing pLSKS.