FIG. 4.

(A) Northern blot hybridization of E. faecalis JH2-2 RNA extracted from exponentially growing cells (lane 1) and from cells harvested 1 h after the onset of stationary phase (lane 2) and from exponentially growing cells incubated for 3 h in seawater (lane 3). (B) Dot blot hybridization of total RNA (1 μg) harvested from exponentially growing E. faecalis JH2-2 cells (spot 1) and from exponentially growing cells incubated for 10 min in 50 μM CdCl₂ (spot 2) or incubated for 1 and 3 h in tap water (spots 3 and 4, respectively). (C) Northern blot hybridization of E. faecalis JH2-2 RNA extracted from exponentially growing cells (lane 1) and from exponentially growing cells incubated for 10 min in 0.08% bile salts (lane 2), 2 mM tBOOH (lane 3), 2.4 mM H₂O₂ (lane 4), 50°C (lane 5), 0.01% SDS (lane 6), pH 4.8 (lane 7), or 1 M NaCl (lane 8). Hybridizations were performed with a single-stranded DNA probe which corresponds to the SP1-S1 region. The size of the transcript determined with RNA molecular size markers (Amersham) is indicated on the left.