Figure 4. Immunogold labeling and transmission electron microscopy of pilus-like structures on the cell surface of S. suis P1/7 and its derived mutants.

In the WT strain P1/7 (left) immunogold labeling showed the presence of thin pilus-like structures that were entirely decorated by the anti Sfp1-specific antiserum and 10 nm colloidal gold-conjugated anti-rabbit IgG antibodies. In contrast, no labeling was detected in the Δsfp1 mutant (center) while the ΔsrtF mutant (right) presented labeling of the bacterial surface but not pilus-like appendages. Magnification: 60,000×.