Dataset Information

Phosphoketolase pathway dominates in Lactobacillus reuteri ATCC 55730 containing dual pathways for glycolysis.

ABSTRACT: Metabolic flux analysis indicated that the heterofermentative Lactobacillus reuteri strain ATCC 55730 uses both the Embden-Meyerhof pathway (EMP) and phosphoketolase pathway (PKP) when glucose or sucrose is converted into the three-carbon intermediate stage of glycolysis. In all cases studied, the main flux is through the PKP, while the EMP is used as a shunt. In the exponential growth phase, 70%, 73%, and 84% of the flux goes through the PKP in cells metabolizing (i) glucose plus fructose, (ii) glucose alone, and (iii) sucrose alone, respectively. Analysis of the genome of L. reuteri ATCC 55730 confirmed the presence of the genes for both pathways. Further evidence for the simultaneous operation of two central carbon metabolic pathways was found through the detection of fructose-1,6-bisphosphate aldolase, phosphofructokinase, and phosphoglucoisomerase activities and the presence of phosphorylated EMP and PKP intermediates using in vitro 31P NMR. The maximum specific growth rate and biomass yield obtained on glucose were twice as low as on sucrose. This was the result of low ATP levels being present in glucose-metabolizing cells, although the ATP production flux was as high as in sucrose-metabolizing cells due to a twofold increase of enzyme activities in both glycolytic pathways. Growth performance on glucose could be improved by adding fructose as an external electron acceptor, suggesting that the observed behavior is due to a redox imbalance causing energy starvation.

SUBMITTER: Arskold E

PROVIDER: S-EPMC2223725 | biostudies-literature | 2008 Jan

REPOSITORIES: biostudies-literature

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Phosphoketolase pathway dominates in Lactobacillus reuteri ATCC 55730 containing dual pathways for glycolysis.

Arsköld Emma E Lohmeier-Vogel Elke E Cao Rong R Roos Stefan S Rådström Peter P van Niel Ed W J EW

Journal of bacteriology 20071026 1

Metabolic flux analysis indicated that the heterofermentative Lactobacillus reuteri strain ATCC 55730 uses both the Embden-Meyerhof pathway (EMP) and phosphoketolase pathway (PKP) when glucose or sucrose is converted into the three-carbon intermediate stage of glycolysis. In all cases studied, the main flux is through the PKP, while the EMP is used as a shunt. In the exponential growth phase, 70%, 73%, and 84% of the flux goes through the PKP in cells metabolizing (i) glucose plus fructose, (ii) ...[more]

PMID: 17965151

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Project description:Following an application from BioGaia AB submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Sweden, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to orodispersible lozenges containing a combination of Lactobacillus reuteri DSM 17938 and Lactobacillus reuteri ATCC PTA 5289 and normal gum function. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The Panel considers that orodispersible lozenges containing L. reuteri DSM 17938 and L. reuteri ATCC PTA 5289 are sufficiently characterised. Maintenance of normal gum function is a beneficial physiological effect. Out of the two studies from which conclusions could be drawn and that investigated the effect of lozenges containing L. reuteri at the proposed conditions of use (i.e. consumption twice daily) on appropriate gingival outcomes (bleeding on probing (PoB) and gingival index (GI)) in subjects with gingivitis, but without periodontitis, one showed a large effect on BoP and other gingival outcomes and one showed no effect. No effect was found in one study with the use of one lozenge daily. The three studies that investigated, at the proposed conditions of use, modified GI (and not BoP or GI) in subjects with gingivitis, but without periodontitis, or were conducted in patients with periodontitis support an effect of lozenges with L. reuteri on gum function. Some evidence has been provided for mechanisms by which consumption of lozenges containing L. reuteri could improve outcomes of gingivitis in patients with chronic periodontitis but the relevance of such mechanisms for the target population of the claim (i.e. subjects without periodontitis) is unclear. The Panel concludes that the evidence provided is insufficient to establish a cause and effect relationship between the consumption of orodispersible lozenges containing a combination of L. reuteri DSM 17938 and L. reuteri ATCC PTA 5289 and maintenance of normal gum function.

Dataset Information

Phosphoketolase pathway dominates in Lactobacillus reuteri ATCC 55730 containing dual pathways for glycolysis.

Publications

Phosphoketolase pathway dominates in Lactobacillus reuteri ATCC 55730 containing dual pathways for glycolysis.

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