Freshly prepared bacterial cell sus

Freshly prepared bacterial cell suspensionswere incubated together with polystyrene disks ona rotary shaker at 25°C. After incubation for 0.5 h, the diskswere taken from the suspension and rinsed gently for 30 s in0.1 M phosphate-buffered saline to remove nonattachedcells. The rinsing was performed by moving the disks slowlythrough the water to prevent detachment of cells due toshear forces. Possible transfer of the cells from the polystyrenesurface to the air-water interface during the washingprocedure could not occur because a drop of liquid alwaysremained on the disk during the washing procedure. Rinseddisks were dried and colored with Erythrocyne red. Thenumber of cells adhering to the surface were counted undera light microscope with a calibrated eyepiece. Surface coveragewas calculated by multiplying the number of cells persquare meter by the cross-sectional area of the cell.