Fig. 6.
Secretion profiles of B. bronchiseptica strain RB50 and isogenic Bvg− phenotypic phase-locked derivative RB54. Proteins were recovered from supernatant fluids of B. bronchiseptica strains cultured for 16 h in iron-replete (+Fe) or iron-depleted (−Fe) SS medium and separated by SDS-PAGE. Sizes of molecular mass markers (M) are given in kDa. (A) Secreted protein profiles of RB50 and RB54. Normalized sample loads represent proteins recovered from 1.2 ml of supernatant fluid (cell densities [OD600] of cultures: RB50 +Fe, 5.52; RB50 −Fe, 2.80; RB54 +Fe, 8.89; RB54 −Fe, 2.18). Bands (white arrows numbered 1 to 6) were excised from replicate gels for identification by LC-MS/MS. (B) Secreted proteins from RB50 cultures used as RNA sources in microarray analysis. The black arrow indicates the Bsp22 protein band in −Fe samples. Normalized sample loads represent proteins recovered from 1 ml of supernatant fluid. Bands (white arrows numbered 7 to 9) were excised from replicate gels for identification by LC-MS/MS. (C) Protein identities as determined by LC-MS/MS. Relative abundance of BteA (also known as BopC) in 16-h +Fe and −Fe sample bands was estimated by spectral counting (quantitative value). ND, not determined.