FIG 2.

Rapid development of nfxB mutants in a 24-h-old PAO1 flow cell biofilm treated with low-dose CIP. The biofilms of PAO1-mCherry-P_CD-gfp+ were grown in flow cell chambers with a continuous flow of minimal medium for 24 h at 37°C and then grown for an additional 24 h with 0.2 μg/ml CIP (24 h +CIP for 24 h) or without CIP (24 h −CIP for 24 h). Red shows wild-type cells (elongated or filamentous) due to the constitutive expression of mCherry, and green shows nfxB mutants due to the expression of GFP via the P_CD-gfp+ reporter. z-stacks were generated by using a Zeiss LSM 710 microscope and processed with Imaris 8.2 software (Bitplane). Top-row images show orthogonal 3D views, and middle and bottom (for treated biofilms only) rows show perspective 3D views of biofilms with an overlay of red and green fluorescence. The images shown are representative of results for two independent flow cell channels.