FIG. 2.
Activation and inhibition of RNAIII transcription in agr group IV strains by culture supernatants. Early-exponential-phase bacteria (5 × 107 cells/ml, strain RN4850, lanes 1, 3, 5, and 6, or RN4846, lanes 2 and 4) were treated with Casamino Acids-yeast extract broth (lanes 1, 2, and 5), with supernatant from post-exponential-phase cells of the same strain (lanes 3 and 4), or with supernatant from a group II strain (RN6607) (lane 6). Whole-cell RNA samples were prepared after 1 h (lanes 1 to 4) or after 80 min (lanes 5 and 6) (5) and analyzed by Northern hybridization with an RNAIII-specific probe.