FIG. 6.

Northern blot analysis for the detection of the phage-encoded sak. Strain 8325-4φ13 was treated with one-half the MIC of either ciprofloxacin (Cipro; lanes +) or trimethoprim (Trim.; lanes +) or with 300 ng/ml mitomycin C (Mito.; lanes +) or was left untreated (lanes −). (A) The blots were hybridized by using digoxigenin-labeled PCR fragments specific for sak; (B) loading control; the intensities of the 23S and 16S rRNA bands stained with ethidium bromide were equivalent in all the samples before Northern transfer.