Fig. 3.

Phase variation of PSH in ΔungD1ΔungD2 mutant. (A) Appearance of cultures after overnight growth demonstrating that most of the bacteria with deletions of ungD2 are settled at the bottom of the tube compared with the wild-type culture and that the acapsular mutant grows as a completely aggregated population. (B) PCR-digestion scheme used to determine quantitatively the portions of a given population with the PSH promoter in the on and off orientations. (C) PCR-digestion results for the PSH promoter from the aggregated bacteria versus those growing in suspension for the ΔungD1ΔungD2 mutant. (D) PSH promoter orientations of bacteria from fecal samples of mice monoassociated with ΔungD1ΔungD2 for various intervals. (E) PSH promoter orientations of bacteria from fecal samples of 2 mice monoassociated with wild type for 7 or 28 days.