Aufklärung grundlegender Aminosäuresynthesewege von Streptococcus pneumoniae mittels Isotopolog Profiling und Einfluss des Glutaminmangels auf die bakterielle Virulenz Streptococcus pneumoniae (pneumococci) are human pathogens which are able to pass the host nasopharyngeal barriers and cause severe diseases such as pneumonia meningitis and septicemia. As pneumococci are members of the order of lactobacillales the major catabolite of carbohydrate metabolism under aerobe and microaerophilic atmosphere is lactate. However S. pneumoniae synthesizes also a large fraction of ABC transporter systems involved in uptake and metabolism of carbohydrates soluble compounds and amino acids. Here we started to analyze carbon metabolism by 13C isotopologue perturbation after growth of pneumococci in chemically defined media (CDM) in the presence of [U 13C6]glucose or [1 2 13C2]glucose as the sole C source. GC MS analysis showed a pattern of labeled and non labeled amino acids. The results suggest that pneumococci take up specific amino acids while others are synthesized de novo by classical or non classical biosynthesis pathways. His Glu Ile Leu Val Pro and Gly remain unlabeled which is a hint for the lack of de novo synthesis pathways or their regulation under certain environmental conditions. Strikingly the data for the essential branched amino acids (BAA; Ile Leu and Val) are unexpected as genes encoding enzymes required for the synthesis were annotated (http: www.genome.jp kegg ). Moreover Asp is not synthesized via the general pathway including pyruvate and acetyl CoA ... Stoffwechsel Virulenz Streptococcus pneumoniae Glutaminstoffwechsel Aminosäurenstoffwechsel Isotopolog Profiling Langzeit NMR Glutamintransporter GlnQPH