Figure 5

Metabolic capacity of S. typhimurium in the host cell or in vivo. (A) In silico flux range for operational metabolic reactions in a simulated host environment using flux variability analysis. The plot shows the flux span normalized to the maximum cytochrome b556 production flux. The red area indicates the flux span during optimal growth of salmonella, while the yellow area represents the flux span during suboptimal growth. During sub-optimal growth, a higher internal flexibility is observed as compared to that during optimal growth. 417 reactions are predicted to be operational during optimal growth and an additional 319 are operational during suboptimal of salmonella inside the host cell. (B) Comparison of in silico prediction of the reactome (red) to the established metabolic proteome (light blue) [5] and transcriptome (green) [2] of S. typhimurium extracted from macrophage post infection and under different in vitro environmental conditions (orange) [56]; 88% of the metabolic proteome, 80% of the metabolic transcriptome and 83% of the proteome established as a result of 3 different environmental responses in vitro are a subset of the in silico predicted reactome. Several genes down regulated in the metabolic transcriptome are associated with blocked reactions (i.e. inactive reaction in host cell environment) and correlate with those predicted in silico using FVA.