Study of the physiological characterization of three lactic acid bacteria and their isogenic ldh deletion mutants

SysMO is a European transnational funding and research initiative on "Systems Biology of Microorganisms".

The goal pursued by SysMO was to record and describe the dynamic molecular processes going on in unicellular microorganisms in a comprehensive way and to present these processes in the form of computerized mathematical models.

Systems biology will raise biomedical and biotechnological research to a new quality level and contribute markedly to progress in understanding. Pooling European research ...

Comparative Systems Biology: Lactic Acid Bacteria

Challenge: Comparative analyses, as demonstrated by comparative genomics and bioinformatics, are extremely powerful for (i) transfer of information from (experimentally) well-studied organisms to the other organisms, and (ii) when coupled to functional and phenotypic information, insight in the relative importance of components to the observed differences and simalities. The central principle of this proposal is that important aspects of the functional differences between organisms derive not ...

S. pyogenes M49 (591), E. faecalis V583, and L. lacis NZ9000 and their isogenic ldh deletion mutants were grown glucose free CDM-LAB medium in BIOLOG phenotype microarray plates PM01 and PM02. With this assay the abilitiy of the strains to grow on 190 different carbon sources was determined in 96 well format.

L. lactis, E. faecalis and S. pyogenes are referred to as LAB because of the fact that in the presence of glucose lactate is produced as the main fermentation product . This metabolic pathway is relatively inefficient, since only 2 ATP are generated from one glucose molecule. All three LAB possess the genetic make up for mixed acid fermentation, a more effective way of fermentation generating 3 ATP per molecule of glucose. All three genomes reveal (at least) two genes encoding a lactate dehydrogenase ...

L. lactis, S. pyogenes and E. faecalis were grown in C-limited chemostat cultures at various pH's and dilution rates. General flux distribution, yields and other physiological factors were studied.

. L. lactis (NZ9000), E. faecalis (V538) and S. pyogenes (M49) wild type strain and their ldh- mutants were grown in batch cultures at 37°C in anaerobic 96 wells plates in either TH-broth supplemented with 0.5% (w/v) yeast (THY) or a chemically defined medium for LAB (pH 7.4) (CDM-LAB (10)). Both media were buffered with either 100 mM MES buffer or 100 mM MOPS buffer for growth at pH 6.5 and 7.5 respectively.

S. pyogenes was grown in C-limited cultures at pH 6.7 and 7.5 and at a growth rate of 0.05 and 0.15

E. faecalis was grown in C-limited cultures at pH 6.7 and 7.5 and at a growth rate of 0.05 and 0.15

L. lactis was grown in C-limited cultures at pH 6.7 and 7.5 and at a growth rate of 0.05, 0.15 and 0.40