FIG 1 .

Assays of biofilm formation by P. denitrificans Pd1222 and by ΔbapBCD and ΔbapA mutants. Cultures were incubated for 72 h without shaking in 6-cm-diameter petri dishes. The growth medium was liquid L broth, supplemented with 10 mM calcium chloride as indicated. (A and B) Dishes were washed, stained with crystal violet, and photographed from the top (A) and side (B). (C) Crystal violet was extracted from biofilms and quantified by absorption at 595 nm. Means and standard deviations were calculated from results of triplicate assays. wt, wild type.