FIG 1.

Pairwise summation of long-range Lifshitz-Van der Waals molecular interaction forces in the bacterial cell and substratum yields the long-range adhesion force between the interacting surfaces. Deformation of the bacterial cell wall brings more molecules in the bacterium into the close vicinity of the substratum, which increases the adhesion force. In this schematic, the undeformed bacterial cell is taken as a sphere with radius R₀ deforming under the influence of the adhesion forces into an oblate spheroid with polar radius r and equatorial radius R. D indicates the separation distance.