FIGURE 7.
Pellicle formation of S. typhimurium csgA− was complemented by exogenous E. coli CsgA subunits. S. typhimurium WT, csgA−, or csgBA− mutants were incubated in static LB-no salt for 3 days at 26 °C in glass tubes. 10 μg/ml of freshly purified CsgAEC or CsgAEC seeds, or products from a mock CsgA purification from strains harboring an empty vector were added to each tube. The liquid culture underneath pellicles was removed and tubes were stained with crystal violet. When the liquid media was removed, pellicles fell against the wall of the glass tubes.