FIG. 2.

RcsB enhances piliation. Cells were grown aerobically with 250-rpm agitation at 37°C in tryptone broth. Samples were negatively stained with 2% phosphotungstic acid (pH 7.0) and observed with a JEM-1200EXII electron microscope (JEOL, Tokyo, Japan). Micrographs were taken at an accelerating voltage of 80 kV. Transmission electron micrographs of WT cells (strain AJW678) (A) and rcsB mutant cells (strain AJW2143) (B) harvested at an optical density at 600 nm of 0.5 are shown. The thin and thick appendages are type 1 pili and flagella, respectively. The bar represents 2 μm. (C) Histogram showing percentages of piliated cells harvested at either 0.5 (solid bar) or 1.0 (open bar) optical density units at 600 nm. The sample sizes ranged from 83 to 178 cells.