FIGURE 4.

¹³C profiles of de novo synthesized amino acids of S. suis strain 10 cultivated in porcine blood and cerebrospinal fluid ex vivo. A, color map for the overall ¹³C excess (mol %) of labeled amino acids after growth of S. suis strain 10 in porcine blood (B columns) and cerebrospinal fluid (C columns) in the presence of [U-¹³C₆]glucose or [1,2-¹³C₂]glucose. White boxes indicate amino acids that could not be detected in these experiments. Mean values of five (blood) and six (CSF) biological replicates for which MS measurements were performed in triplicate are given. B and C, relative isotopologue composition of amino acids derived from S. suis grown in porcine blood (B columns) and cerebrospinal fluid (C columns) with [U-¹³C₆]glucose (B) or [1,2-¹³C₂]glucose (C). ¹³C excess values (mol %) are shown as black columns on the left y axis. Colored columns on the right y axis indicate the percentages of labeled isotopologues comprising up to nine ¹³C atoms (M+1 to M+9). Mean values are shown for five (blood) and six (CSF) biological experiments each measured in triplicate. The horizontal line indicates the detection limit set to 0.5 mol % ¹³C excess in these experiments. D, relative fractions of isotopologues in the Ala-232 and Ala-260 fragments, which were relevant to discriminate glucose fluxes of the EMP pathway and the PPP, are shown. S. suis strain 10 was incubated for 6 h in porcine cerebrospinal fluid (C columns) or porcine blood (B columns) supplemented with 5 mm [1,2-¹³C₂]glucose, respectively. Colored columns on the left y axis indicate the percentages of isotopologues comprising up to three ¹³C atoms (M+1 to M+3). Note that M+0 stands for unlabeled Ala and indicates uptake of extracellular Ala. Mean values and standard deviations are shown for two independent biological experiments, each measured in triplicate.