Figure 2.

PCA scores plots generated from 1D ¹H NMR spectra obtained from M. smegmatis TAM23 (red) and mc²155 (blue) cell lysates (A) without or (C) with media supplemented with D-alanine. OPLS-DA S-plots comparing the 1D ¹H NMR spectra obtained from TAM23 and mc²155 cell lysates (B) without or (D) with media supplemented with D-alanine. Each point in the S-plot represents a specific bin of integrals for a chemical shift range of 0.25 ppm. The points at the extreme ends of the S-plots are major contributors to class distinction. The red points represent a decrease in the binned integrals for TAM23 compared to mc²155. The blue points represent an increase in the binned integrals for TAM23 compared to mc²155. Green points represent metabolites that are approximately equally in both strains. The labeled points were assigned to the following metabolites: 1) fatty acids, 2) ethanol, 3) glutamate, 4) oxaloacetate, 5) GABA, 6) succinate, 7) glycerol, 8) isoleucine, 9) valerate, 10) lactate, 11) N-acetylglucosamine-6-phosphate, 12) α-ketoisovalerate, 13) glycolate, 14) serine, 15) phosphoserine, 16) threonine, 17) lysine, 18) alanine, 19) glucarate, 20) ATP, 21) unidentified (UD), 22) trehalose, 23) valine, 24) ornithine, 25) α-ketoglutarate and 26) citrulline.