FIG 2.

Both the mucoid polymer and the biosurfactant are regulated by RsmE, but not by RsmA or RsmI. (A) Colony morphology comparisons of WT and deletion mutants of rsmE, rsmA, and rsmI. Liquid cultures were spotted on PAF plates 7 days prior to capturing the images. Only the ΔrsmE strain was mucoid in appearance, and new mucoid patches naturally emerged in WT, ΔrsmA, and ΔrsmI colonies that characteristically represented de novo rsmE mutations. Scale bar, 10 mm. (B) Comparison of biosurfactant production on the dull (left) and shiny (right) sides of the polycarbonate membrane overlaid on PAF. The M strain is a naturally selected mutant from a WT colony and harbors a frameshift mutation in rsmE. Only the ΔrsmE and M strains produced the biosurfactant ring on the dull side, which promoted spreading of cells on the shiny side of the membrane.