Figure 5. M. tuberculosis co-metabolises nitrogen sources.

(a) Representative extracted ion chromatograms (EICs) for intracellular metabolites from cultures obtained in the presence of dual nitrogen sources (Glu + Gln or Asp +Asn), with one of the nitrogen sources ¹⁵N-labelled. (b) Representative mass spectra corresponding to the metabolites in Figure 5a. The following m/z values were used in positive mode (M + H)⁺: Glu – 148.0604, ¹⁵N-Glu – 149.0575, Gln – 147.0764, ¹⁵N-Gln – 148.0735, ¹⁵N₂-Gln – 149.0705, Asp – 134.0448, ¹⁵N-Asp – 135.0418, Asn – 133.0608, ¹⁵N-Asn – 135.0578, and ¹⁵N₂Asn – 135.0548. (c) Combined labelling data obtained for the same metabolites, in different combinations of two carbon sources. Bars are averages of three biological replicates, colour indicates labelled metabolites/nitrogen sources and error bars are the standard error of the mean.

Figure 5—figure supplement 1. Growth of M. tuberculosis in single or dual nitrogen sources.

On the top panel, growth curves are shown to illustrate the delay in growth observed at 8 mM (green, yellow, dark purple and teal traces), in comparison to the rest of the conditions. On the bottom panel, average OD values obtained at 20 days are re-plotted.