Figure 4.

Biofilm formation by the wild‐type (WT), ΔpilA and ΔtfpO mutants and the ΔtfpO complemented strain. Each bacterium was grown in Luria–Bertani (LB) broth medium with 10 mm MgCl₂, transferred to fresh MMMF medium (see Experimental procedures) and incubated for 48 h at 25 °C without agitation. Averages obtained from three independent experiments are shown. Asterisks indicate a significant difference from the WT in a t‐test (**P < 0.005).