FIG. 1.

(a) Water-insoluble glucans synthesized by S. mutans glucosyltransferase B (labeled with Alexa Fluor 647; maximum absorbance wavelength, 647 nm; maximum fluorescence emission wavelength, 668 nm). (a-1) Phase-contrast image of glucans before excitation with a laser at 633 nm (×20 oil objective; numerical aperture, 0.70). (a-2) Fluorescence image of glucans (adapted from reference 22). (b) Saliva-coated hydroxyapatite (sHA) biofilm model: simultaneous visualization of EPS (red) and bacteria and microcolonies (green) in a three-dimensional image of an S. mutans biofilm formed on the surface of an sHA disk.