Comparison of gene expression patterns between mutant and parental strains, based on the predictions of the SPABBATS algorithm for pathway analysis. The predictions of the SPABBATS algorithm (see Figure 2) were further characterised by transcription analysis. The expression of the ald and bcd genes remains constant between the mutant (GP717) and parental (GP28) strains, suggesting that these genes are not involved in the newly activated catabolic pathway. In contrast, the expression of the ansAB operon is strongly increased in the mutant. This hints to a gain of function in the mutant strain that was analyzed further.