Fig 4.

(A) Yeast cells binding to C3091 fimbriae in a PPFC. Fimbriae were immobilized on the surface of the flow chamber, yeast cells were loaded and allowed to settle, and then the flow was turned on at various shear stresses. The numbers of yeast cells at the surface moving slower than the free-floating cells were determined for all shear stress values and divided by the initial number of cells, to calculate the percentage. Error bars represent the standard deviations of bound yeast cells throughout the recorded video for duplicate experiments. As a negative control, the same set of experiments was performed on bacterial cell debris quenched (i.e., debris from the expressing strain from which type 3 fimbriae were purified, without type 3 fimbriae), with plates without immobilized type 3 fimbriae. Here, no slowing of yeast cells on the surface was observed; all the cells were moving with hydrodynamic velocity (data not shown). (B) Yeast cells binding to isogenic strains expressing MrkD protein variants from strains C3091, FHM19, and 3148. Bacteria were immobilized on the surface of the flow chamber, yeast cells were loaded and allowed to settle, and then the flow was turned on at various shear stresses. The numbers of yeast cells at the surface moving slower than the free-floating cells were determined for all shear stress values and divided by the initial number of cells, to calculate the percentage. Error bars represent the standard deviations of bound yeast cells throughout the recorded video for duplicated experiments.