Experimental design and strategy for microarray data analysis.

<p>A. Scheme representing the four experimental conditions and transcriptome comparisons. B. Cross-comparative analysis accomplished to identify strain-specific and common responses under the two conditions tested. The transcriptome data were processed as indicated in order to identify gene expression profiles associated with the strain and the colon explant contact. A/B designates the pool of genes overexpressed in condition A compared to condition B. + means that the common overexpressed genes of the comparisons are kept, whereas - indicates genes that were discarded. Note that the profiles obtained by this strategy are composed of genes with increase transcript levels in a particular strain versus the other.