FIG. 6.

TCA cycle inactivation derepresses icaADBC transcription. Total RNA was isolated from S. epidermidis strains 1457 and 1457-acnA, 1457-sarA, 1457-icaR, and 1457-sigB, and Northern blot analysis was performed using an icaD-specific probe. To make certain equivalent quantities of RNA were loaded, 23S and 16S rRNA were visualized by ethidium bromide staining and used as loading controls (bottom blots). To permit direct comparison of autoradiographs, total RNA from strains 1457-acnA and 1457 isolated at 6 h and 4 h postinoculation, respectively, were used to normalize the exposure times. (To minimize variation, the same preparations of RNA were used as exposure controls in all experiments.) The results are representative of at least two independent experiments.