Figure 2

Comparison of microarray analysis to real-time PCR revealed 78% of true positives. Log2-values of fold-changes of differentially expressed genes under stringent conditions are shown for normalized microarray data and RT-qPCR of 13 ORFs (out of 40 total; see also Additional file 2: Figure S1) representing the different functional groups: A- Amino acid metabolism; B- Cell Division; C- Cell envelope; D- Central intermediary metabolism; G- Detoxification. Expression of 78% of all chosen ORFs (including those presented in Additional file 2: Figure S1) was consistent for both methods, with a log2(x) > 0.66 or log2(1/x) < −0.66 (representing a plain fold-change > 1.5). For the remaining 22%, the fold-change was inferior to log2(x) = 0.66 or superior to log2(1/x) = −0.66 (representing a fold change < 1.5) or not consistent with microarray analysis. Relative differences of transcription levels between B. suis wild-type and the Δrsh mutant were determined as 2^-ΔΔCt values, as described in Methods.