Figure 2. Incorporation of ¹³C atoms in central metabolites after a pulse of ¹³C-acetate during exponential growth on glucose or during the acetate consumption phase.

E. coli K-12 MG1655 was grown on M9 supplemented with 15 mM glucose. ¹³C-acetate was added at a final concentration of 1 mM in mid exponential phase (dark grey bars) or during the phase of net acetate consumption (light grey bars). Intracellular metabolites were collected before each isotopic switch and one hour after the addition of labeled acetate, and the molecular ¹³C-enrichments of central metabolites were quantified by mass spectrometry. Results are displayed as the ratio between the ¹³C-enrichments of metabolite before and after the pulse. Asterisk (*) represents a p-value lower than 0.01 when compared to the label incorporation observed during glucose consumption.