FIG. 7.

Fba is removed from the cell surface in stationary phase. (A) FH binding activity is lost in stationary phase. Wells of microtiter plates were coated with GAS grown to mid-exponential phase (hatched bars) or stationary phase (open bars). FH binding was assayed and is presented as described in the legend to Fig. 2. (B) E64 stabilizes FH binding activity. Microtiter plates were coated with GAS grown to stationary phase in THY medium (open bars) or THY medium containing 25 μM of E64 (hatched bars). (C) E64 stabilizes Fba expression. Wells were coated with GAS grown to stationary phase in THY medium (open bars) or THY medium containing 25 μM of E64 (hatched bars). Fba expression was assayed with Fba antiserum. All data are from two independent experiments in which assays were performed in triplicate (panels A and B) or duplicate (panel C).