FIG. 5.

(A) Growth curve (closed triangles) and CAT specific activities (open circles) for S. mutans GMS100 cultures grown in CDM supplemented with 1% glucose. Each CAT specific activity data point represents the mean of values from three independent experiments. Standard deviations are negligible except where indicated by vertical bars. (B) Total RNA (1 μg) isolated from S. mutans UA130 grown to early, mid-, or late logarithmic phase or to stationary phase in CDM supplemented with 1% glucose was dot blotted onto a nitrocellulose membrane and probed with a DNA fragment which is internal to dlt1. Individual dots were excised, and the radioactivity was counted in a Packard Tri-Carb model 1900CA liquid scintillation analyzer. A dot representing nonspecific hybridization was included as a control. Shown are the results of a single representative experiment. Note the maximal expression of dlt during mid-logarithmic phase.