FIG. 4.

(A) Transcriptional analysis of RNAIII, hla, sspA, and spa in an rsr-sarR and an rsr-agr double mutant from post-exponential-phase cells (OD₆₅₀ of 1.7), treated with RNase-free DNase, reverse transcribed into cDNA, and analyzed by real-time PCR. (B) Real time-PCR of RNAIII of late-exponential-phase cells (OD₆₅₀ of 1.1) from rsr, sarR, sarR-agr, and rsr-sarR mutants. Transcription levels in the mutants are normalized to the levels of gyrB and are reported relative to their transcription in the SH1000 parent (set to 1). The error bars represent individual standard deviations. The P values for SH1000 compared to the single rsr mutant, sarR mutants, and double mutants are <0.0008, <0.02, and <0.0006, respectively. The P values for the rsr-sarR double mutant compared to the rsr single mutant and the sarR mutant are <0.005 and <0.008, respectively.