FIG. 4.

TCA cycle intermediates stimulate biofilm formation. (A) Diagram of the TCA cycle. Boxed compounds stimulate biofilm formation in an FnbA-dependent manner. (B) Biofilm formation by the WT (black bars) and the fnbA mutant (white bars) in the presence of TCA cycle intermediates. Saline served as a control in these studies. The biofilm assay was performed as described in Materials and Methods. (C) Biofilm formation by the WT (black bars) and the acn mutant (white bars) in the presence of TCA cycle intermediates. These assays were performed as described above (B). (D) Expression of the fnbA-gfp fusion was assessed in a solution containing TSB plus 0.2% glucose supplemented with saline or the indicated TCA cycle intermediates. Expression is presented as relative fluorescence units (RFU).