FIG. 1.

(A) Southern hybridization of HindIII-digested DNA from biofilm-defective S. gordonii fruK::Tn917-lac mutant. Digoxigenin-labeled pTV32-OK containing Tn917-lac (which has two HindIII sites) was used as the probe. Three hybridizing bands were produced with HindIII-digested DNA, demonstrating the presence of a single transposon insertion. (B) Gene organization of the fructose PTS operon. Genes of the fructose PTS operon are shown in grey. fruR encodes a putative transcriptional repressor, fruK encodes a fructose-1-phosphate kinase, and fruI encodes a fructose-specific enzyme II (EIIABC components). Maps of S. gordonii Challis 2 and fruK::Tn917-lac mutant are shown along with the corresponding biofilm phenotypes on polystyrene, uncoated glass, and saliva-coated glass surfaces as determined directly by phase-contrast microscopy. Cells were grown in BM for 24 h at 37°C under anaerobic conditions.