cultured in minimal medium with 0.3% unlabeled glucose to
OD600=0.4 in an anaerobic chamber heated to
37°C and transferred to a prewarmed filter membrane as described
for metabolomics extractions. Medium switch was performed under
continual flow of minimal medium with 0.3% of 100%
[U-13C]-glucose (Cambridge Isotope
Laboratories CLM-1396-PK) for up to 5 minutes, and metabolites were
extracted after 10, 20, 40, 80, 160 and 320 seconds as described above
(without the spike-in of the 13C labeled internal standard).
The acetate growth shift experiment was conducted following the same
procedure, with the cells grown in minimal medium containing
0.3% unlabeled glucose and 0.1% unlabeled acetate and
switched to medium containing 0.3% unlabeled glucose and
0.1% of 100% [U-13C]-acetate
(Cambridge Isotope Laboratories).