Western blotting. (A) The identification of the mutant Yb2Δ02955 and complementation strain cYb2Δ02955. Lane M, PageRuler prestained protein ladder; lanes 1 to 3, whole-cell proteins from Yb2, Yb2Δ02955, and cYb2Δ02955 strains, respectively. A mouse antiserum directed against the TonB-dependent receptor of R. anatipestifer was used to control for protein loading. (B) The identification of the bacterial secretion proteins. Lane M, PageRuler prestained protein ladder; lanes 1 to 3, secretion proteins from Yb2, Yb2Δ02955, and cYb2Δ02955 strains, respectively. The TonB-dependent receptor was used to control for protein loading.