Time course of loss of adhesion and accompanying microscopic and macroscopic structural changes. a) Cryosections of biofilms at different time points. Sections acquired at 30 and 60 min appear to conform to the curved surface of the tubing. Arrows indicate substratum side. The structure in which hyphae at the edges extend into the surrounding medium becomes apparent between 60 and 90 min. (Scale bars are all 50 μm). b) SEM images of the colonized (lower) surface of the tubing after the tubing was drained. Between 60 and 90 min there is a sharp transition in which most of the cells have lost their surface adhesion. (Scale bars are all 20 μm). c) Time course of gross structural changes during loss of adhesion. The biofilm is visible at 40 min. At 90 min the flanking sections detach as flaps (arrow); these flaps are more visible at later time points. At 135 min wrinkles begin to form (arrow) and become more prominent at later time points (185 min).