Biofilm-regulated S . Typhimurium gene expression. (A) A subset of genes up-regulated in the biofilm that encode cell surface structures, motility, global regulation, and oxygen diffusion. Representative examples of the functional categories (Figure 1) are shown. (B) Type III secretion genes. Transcriptomic data from the flowing biofilm system (72 h) was normalised to the planktonic samples and values are shown as fold change on a logarithmic scale (e.g. value of 10 on the Y-axis corresponds to 10-fold up-regulated). All genes were significant at P < 0.01 (* denotes that the csgA gene was significant at P < 0.05).