Schematic illustration of the principle of atomic force microscopy and definition of different hyphal regions. (A) Schematic presentation of AFM set-up. A sample with attached C. albicans cells is positioned by a xyz piezo scanner, while a bacterium attached to a tipless AFM cantilever is brought into contact with the hyphal surface. The deflection of the cantilever upon retract is a measure of the adhesion forces between a bacterium and the hyphal surface and is detected by an optical laser. The laser beam is focused on the very end of the cantilever and reflected onto a position sensitive detector from which the adhesion forces can be calculated, provided the mechanical properties of the cantilever are known. (B) Schematic indication of the different hyphal regions defined for bacterial-hyphal adhesion force measurements.