FIG. 5.

Mutation of luxS causes an alteration in S. mutans biofilm. (A) Two images of in vitro biofilms representing both the wild type and the mutant using dark-field microscopy at magnifications ×20 and ×40. Cells were grown on glass coverslips as described in Materials and Methods. Similar results were obtained for more than 100 independent wild-type and luxS mutant biofilms examined. (B) Biofilms were tested for their ability to resist detergent treatment with SDS. Three samples of wild-type and mutant biofilms grown on glass coverslips were shaken at 150 rpm for 1 h. The OD₆₀₀s of the resulting supernatants were compared.