Figure 1

Re-ordered metabolite concentration data. In the lower matrix, the partitioning of columns into regions A, B, C, D, and E after computing the cluster boundaries is presented given the optimal re-ordering over all conditions. The upper matrices illustrate the subsequent optimal ordering of the metabolites over the regions A and E. The labels on the x-axis denote starvation conditions, where "YN" and "YC" denote the starvation of S. cerevisiae, Y, of nitrogen (N) and carbon (C), respectively. Similarly, the x-axis labels "BN" and "BC" denote the starvation of E. coli, B, of nitrogen (N) and carbon (C), respectively. The numbers succeeding these x-axis labels denote the time, in hours, at which the concentration was measured. The y-axis labels in the bottom matrix provide the names of the metabolites. In the upper two matrices, the relative groupings of related metabolites are illustrated using the labels "***" for amino acid metabolites, "ooo" for biosynthetic intermediates, and "+++" for TCA compounds. The values in the data matrix correspond to the logarithm (base 2) of the fold-change in relative metabolite concentration as measured using liquid chromatography and tandem mass spectrometry. Fold-change is relative to exponentially growing cells. Blue colors indicate fold decreases and red colors indicate fold increases.