FIGURE 4.

c-di-GMP accumulation assay using a specific biosensor. Representative images of visible fluorescence of concentrated cultures and microscopic fluorescence detection in individual cells in (A) control strains E. coli S17.1 pDZ-119 and E. coli S17.1 pDZ-119/pGEX; (B) strains overproducing CdgC or CdgA. The microscopic assessment of c-di-GMP levels was performed using a Nikon Eclipse TE2000-U fluorescence microscope. The excitation and emission of the AmCyan fluorophore were recorded at 489 and 519 nm, respectively. The TurboRFP fluorophore was excited at 553 nm, and emission was measured at 574 nm. Images obtained were edited with Nikon NIS Elements software. Bar 10 μm. The data presented are representative of three independent experiments.