Fig 3.

Responses to pH mediated by periplasmic domains of multiple P. aeruginosa chemoreceptors. (A–D) FRET response measurements for E. coli cells that expressed PctA-Tar (A), PctC-Tar (B), PctP-Tar (C), or TlpQ-Tar (D) as the sole chemoreceptor to the indicated changes in pH from default 7.0, which were performed as in Fig. 2. L-Ala (L-alanine), GABA (γ-aminobutyrate), guanine, and D-glucose were used as positive controls for PctA-Tar, PctC-Tar, PctP-Tar, and TlpQ-Tar, respectively. (E) pH taxis of P. aeruginosa PAO1 colonies that were inoculated at different points of the soft-agar plate with the established pH gradient. Estimated pH values along the gradient are indicated.