Gel electrophoresis of proteins extracted from planktonic and sessile PAO1 bacteria. (A) Bacterial suspensions were prepared at 107 or 109°CFU/mL from an overnight culture and cultivated for 3 h or 1 h at 37°C respectively in planktonic or adsorption mode. Proteins were directly extracted from 108 or 109 PAO1 planktonic cells (PC) and sessile bacteria attached to glass wool (GW). (B) Proteins were separated on SDS-PAGE (12%) and stained with a colloidal blue stain. Arrows indicate changes in protein pattern between PC and GW bacterial populations. M: Protein markers.