FIG. 3.

Northern blot analyses of the sar locus. Total RNAs (8 μg/lane) of S. aureus strains BB255 (A), MSSA1112 (B), Newman (C), and their respective sigB mutants were blotted onto positively charged nylon membranes and subjected to Northern blot analyses. RNAs were obtained from cells grown in LB medium at 37°C and harvested at different growth stages (indicated as OD₆₀₀ values [numbers above the lanes]). The blotted membranes were hybridized using a digoxigenin-labeled DNA probe specific for sarA (for details on the construction, see Materials and Methods). The RNA molecular weight marker I (Roche) was used as a size marker. Relevant transcript signals are indicated.