FIG. 3.

(A) Effect of precoating with surfactin on colony morphology. An overnight wild-type (WT) culture was spot inoculated onto EPS agar plates after the plates were coated with 10 μl of 0 or 0.1 mg of surfactin/ml. Colony morphology was observed after 40 h at 32°C (bar, 0.5 cm). Colony margins were observed by microscopy (bar, 100 μm). Cells were lifted from the colony margins, stained, and observed by microscopy for the production of flagella (bar, 10 μm). (B) Effect of precoating with purified biosurfactant from the ΔplcR mutant on colony morphology. Overnight cultures of the wild type and the complemented ΔplcR mutant strain (CM) were spot inoculated onto EPS plates after the plates were coated with 40 μl of Tris-HCl or the purified biosurfactant from the ΔplcR mutant. Colony morphology was observed after 40 h at 32°C (bar, 0.5 cm). Colony margins were observed by microscopy (bar, 100 μm). Cells were lifted from the colony margins, stained, and observed by microscopy for the production of flagella (bar, 10 μm). The results presented are representative of triplicate experiments.