FIG. 9.

Percentages of recovery of sorted cFDA⁺ PI⁻ and cFDA⁺ PI⁺ cells derived from nonadapted and acid-adapted populations after acid challenge at pH 3.5 for 15 min. Medium-based recovery of sorted cells was examined on MRS-MOPS, MRS (pH 6.0 and 5.5), and MRS-MOPS-1% NaCl agar plates. It should be noted that cFDA⁻ PI⁺ cells exhibited no recovery in all cases (data not shown).