Fig. 1.

Conditioning media suppresses flow-sensitive gene expression in P. aeruginosa. (A) Microfluidic setup used in this study. Microfluidic devices are custom fabricated with polydimethylsiloxane and glass coverslips. Channels are 50 µm tall × 500 µm wide. Bacteria adhere to the channel wall. Microfluidic devices are simultaneously subjected to flow from a syringe pump and imaged 1 cm into the channel by a fluorescence microscope. (B) Fluorescence and phase images of the P. aeruginosa fro reporter strain in flow (at a shear rate of 800 s⁻¹) over 180 min. Cell density in channels remains relatively constant due to the combinatorial effects of cell growth and cell departure. Images are representative of three biological replicates. (Scale bars, 5 µm.) (C) Quantification of fro expression by dividing YFP intensity by mCherry intensity as described in SI Appendix, Fig. S1. Green represents cells exposed to LB media, while gray represents cells exposed to conditioned LB. Shaded regions show SD of three biological replicates.