FIGURE 1.

Extracellular Δtggt1 strain is deficient in utilizing glucose-derived carbon, whereas glutamine metabolism is constitutively active. Shown is fractional abundance of ¹³C atoms in the carbon pool of selected metabolites from the indicated parasite strains labeled either with [U-¹³C]glucose or [U-¹³C]glutamine. Extracellular parasites were incubated with 5 mm [U-¹³C]glucose and 2 mm glutamine or with 2 mm [U-¹³C]glutamine and 5 mm glucose for 4 h (37 °C, 5% CO₂) and then subjected to metabolomics analysis by GC-MS, as described under “Materials and Methods” (mean ± S.E., n = 4 assays). Corresponding heat-maps and labeling of individual isotopomers are illustrated in supplemental Figs. S3 and S4, respectively. Statistical significance was measured separately for each group compared with the parental strain using Student's t test (*, p < 0.05; **, p < 0.01; ***, p < 0.001). n.d., not detectable.