FIG. 3.

CsgG is spatially restricted in the outer membrane. (A and B) Typical images of cells obtained after anti-CsgG indirect immunofluorescence staining of the WT (A) or the isogenic csgG mutant (B). Shown are merged images of cells probed with rabbit anti-CsgG primary antibody and goat anti-rabbit secondary antibody conjugated to Alexa488 (green) and DAPI-stained nucleoid (blue). Bars, 12.5 μm. Quantification of the immunofluorescent foci is presented in Fig. 4B (see text). (C and D) Typical transmission EM images obtained after indirect immunogold labeling with 10-nm gold particles of WT cells probed with anti-CsgG antibodies (C) or without primary antibody (D), as described in Materials and Methods. Cells were grown on YESCA plates at 26°C for 40 h to induce curli expression. Bars, 200 nm.