Characterization of flux distribution of S. pyogenes M9 wild type and the arcA- and glnA-knockout mutant in continuous cultures

Comparative Systems Biology: Lactic Acid Bacteria

Basically extending SYSMO-LAB 1st phase into second with addition of fourth species, Lb. plantarum. The main focus is amino acid metabolism. primary metabolisms, like glycolysis is also interest.

Lactic acid bacteria generally use homolactic fermentation for generation of ATP. Here we studied the role of Arginine and Glutamine metabolism on the general physiology of the lactic acid bacteria Streptococcus pyogenes.
A deletion mutant of glnA (glutamine synthetase) has been constructed in the S. pyogenes M49 591 background. The glnA mutant strain shows decreased growth in low glutamine and excess glutamate conditions and no growth at all in low glutamine and low glutamate conditions.
An arcA
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S. pyogenes was grown in C-limited cultures at pH 6.5 and 7.5 and at a growth rate of 0.05
The glnA mutant strain shows decreased growth in low glutamine and excess glutamate conditions and no growth at all in low glutamine and low glutamate conditions. Preliminary results of glucose-limited chemostat cultures indicate a reversion of the pH dependency of the shift from homolactic to more mixed acid fermentation:
wild type - lactate/formate ratio at pH 6.5 = 11.8, at pH 7.5 = 2.8
glnA mutant -
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This HPLC method uses a isocratic method and a RI detector to identify and quantify almost all excreted catabolic metabolites.