Figure 3

Production of type 1 fimbriae by the strain K3. A, B and C) Electron microscopy performed onto χ7122, K3 and CK3 strains, respectively, at 12 000×. Images show a typical field of view of bacteria and demonstrate that the K3 strain lacks fimbriae, compared to the χ7122 and CK3 strains. Arrow shows fimbriae on cell surface. D) Minimal bacterial titer allowing yeast agglutination. The χ7122 Δfim (χ7279) strain was used as negative control and did not show agglutination (data not shown). The § symbol shows that at mid-log phase of growth, no agglutination was observed at the highest cell titer for the K3 strain, which was also observed for Δfim strain χ7279 (data not shown). Asterisks indicate significant differences observed between bacterial concentration of the wild-type χ7122 and the pst mutant strain K3 (P value = 0.0001) as calculated by Student's t test. No difference was observed between the χ7122 and the CK3 strains. E) Western blot of protein extracts from strains χ7122 (lane 1), K3 (lane 2), CK3 (lane 3), and χ7279 (lane 4) using anti-FimA serum.