Representative scatter plot graph (A) and analysis of two-dimensional gel similarities by scatter plot (B). Solid bars, linear dependence; shaded bars, correlation; ∗, reference gel for the scatter plot analysis; CHEMO, chemostat-grown P. aeruginosa strain PAO1; 8 h, 1 day, 6 days, and 12 days, P. aeruginosa strain PAO1 biofilm after 8 h, 1 day, 6 days, and 12 days of attachment time, respectively; tube 8 h, biofilm after 8 h of attachment time; JP1, P. aeruginosa strain PAO-JP1; PAO1, chemostat-grown P. aeruginosa strain PAO1; P. putida (ATCC 39168), chemostat grown. Vol (%), relative volume (according to Melanie 3.0 software description), volume divided by the total volume over the whole image.