Figure 1.
Effect of Bam overexpression on sensitivity to NTZ. Strains BW25113/pMJ3 (PapCHis) + pTRYC (Vector) (A) and BW25113/pMJ3 + pBamABCDE (B) were grown in the presence of the indicated concentrations of NTZ. E. coli containing vector pMON6235Δcat served as a negative control for PapC expression. OM fractions isolated from normalized bacterial cultures were subjected to SDS-PAGE and Coomassie Blue staining to observe PapC and the overall OMP profile (top panels). Samples were also probed with anti-His tag and anti-BamA antibodies to visualize PapC and BamA, respectively (bottom panels). PapC levels were measured by densitometry of the anti-His tag blot, and percentage PapC levels were calculated relative to 0 μg/ml NTZ (C). The graph shows individual data points and means ± S.D. (error bars) from three independent experiments. *, p < 0.05; ***, p < 0.001 for comparison of OM PapC levels at each NTZ concentration.