3-DIMENSIONAL TRACKING OF MOTILE BACTERIA NEAR A SOLID PLANAR SURFACE

Knowing how motile bacteria move near and along a solid surface is cru cial to understanding such diverse phenomena as the migration of infec tious bacteria along a catheter, biofilm growth, and the movement of b acteria through the pore spaces of saturated soil, a critical step in the in situ bioremediation of contaminated aquifers, In this study, a tracking microscope is used to record the three dimensional motion of Escherichia coli near a planar glass surface, Data from the tracking m icroscope are analyzed to quantify the effects of bacteria-surface int eractions on the swimming behavior of bacteria, The speed of cells app roaching the surface is found to decrease in agreement with the mathem atical model of Ramia et al, [Ramia, M., Tullock, D. L, & Phan-Tien, N . (1993) Biophys J. 65,755-778], which represents the bacteria as sphe res with a single polar flagellum rotating at a constant rate, The ten dency of cells to swim adjacent to the surface is shown in computer-ge nerated reproductions of cell traces, The attractive interaction poten tial between the cells and the solid surface is offered as one of seve ral possible explanations for this tendency.