Figure. (A) Two-day-old sucrose-dependent biofilms produced within 24-well microtiter dishes according to previously published procedures (Banas et al., 2001). The GbpA-strain produced a flatter biofilm that coated the surface more evenly. The GbpC-strain produced a biofilm that was at least twice as thick as that produced by wild-type S. mutans. (B) We estimated the thicknesses of the biofilms formed by wild-type and GbpC-strains by inverting the contrast (making the background white and cells black) of microtiter well images and using the software program NIH Image for densitometry.