Figure 4

Validation of selected microarray results with Northern blot analysis. (A) RNAs from wild-type and spf and VSsrna24 deletion mutants (Δspf and ΔVSsrna24, respectively) were separated on 5% denaturating polyacrylamide gels, transferred to membranes and tested for presence of the sRNAs Spot 42, RyhB, Qrr and VSsrna24. 5S rRNA was used as control and to normalize the results. Plus (+) indicates that glucose was added to the culture 15 min prior to sampling, whereas minus indicates that no glucose was added. Numbers to the right of gel pictures indicate the length of RNAs as measured from the gel. Fold change values ≥ 2 are shown below samples, and are always comparisons between deletion mutants and wild-type control samples, at same conditions. (B) Same samples as described above separated on a 1.2% denaturating formamide gel.