FIG. 3.

AI-2 induction in the presence or absence of sugar. S. mutans was grown and assayed as described in Materials and Methods. Cells were grown overnight and resuspended to an OD₆₀₀ of 0.4 in reporter assay (AB) medium and incubated with aeration for 3 h at 37°C. One sample was incubated in AB alone, while for the other, sucrose was added to a final concentration of 1%. The presence of sucrose in the medium caused a potent reduction in luminescence to below background values.