FIG 7.

(A) Western blot analysis for glucosyltransferase derived from cell surface protein extracts of wild-type S. mutans and SMΔtrk2 grown in MMSK with various KCl concentrations. Twenty micrograms of SDS-extracted cell surface proteins from 24-h duplicate cultures of wild-type and trk2-null mutant strains grown in MMSK with 5, 25, and 50 mM KCl were separated on 4-to-20% TGX gradient gels, blotted, and stained for total protein (left) or probed with anti-GtfD (right). (B) Glucan production by S. mutans wild-type (a and b) and trk2-null mutant (c and d) strains. Strains were grown on TSY20B (20% sucrose) agar plates for 48 h at 37°C and an additional 72 h at 25°C. Colony morphology was imaged using a Leica MZ8 dissecting microscope with DFC320 camera and Firecam v.3.4.1 software (Leica Microsystems, Buffalo Grove, IL) using incident lighting. Magnification, ×63 (a and c) and ×160 (b and d).