FIG. 3.

Northern blot analysis of clpL and purCLFMN-vanZ-purH transcripts from S. pneumoniae R6 cells treated with various antibiotics. Growth of cultures, treatment with compounds, and Northern blotting were performed as described in Materials and Methods. (A) Expression of the 2.1-kb monocistronic clpL transcript hybridized to a probe internal to the clpL ORF. (B) Expression of a ≈10-kb purCLFMN-vanZ-purH operon transcript hybridized to a probe that extends from the end of purC to the beginning of purL. (C) Hybridization signals from both blots were analyzed using ImageQuant software (Molecular Dynamics). The relative fold changes in transcript amounts for each treatment were compared to that of the control (DMSO). DMSO, solvent control; Erm, erythromycin; Cm, chloramphenicol; Tet, tetracycline; Pur, puromycin; Rif, rifampin; Str, streptomycin.