Combined analysis of metabolome and transcriptome: Catabolism in bacillus subtilis

Abstract

5. Conclusions: The metabolite profiles of the B. subtilis cells are similarly independent on the carbon sources regardless of whether they suppress others or are suppressed by others. All the similar profiles were measured at the maximum growth rate, suggesting that B. subtilis has a predetermined metabolite profile optimized for the maximum growth rate. Differences in carbon sources induced local perturbations in the predetermined profile. One of such perturbations was the accumulation of the starting metabolites in the suppressed carbon sources. Combined analysis of the metabolite profile and DNA microarrays revealed that the first reaction in the catabolism was rate-limiting when B. subtilis was grown on suppressed carbon sources, although the enzyme genes of the reactions were upregulated. The present analysis suggests that the decrease or increase in the gene expression of an enzyme does not always result in the accumulation or decrease in its substrates or products, because of the multiplicity of metabolic pathway networks. Metabolome and transcriptome data that supplement each other provide much informatiion to study the global regulation of metabolism.