PUL ID

PUL0203

PubMed

25841008, Appl Environ Microbiol. 2015 Jun 15;81(12):3973-83. doi: 10.1128/AEM.00149-15. Epub 2015 Apr 3.

Characterization method

qPCR, thin layer chromatography, substrate binding assay

Genomic accession number

NC_004663.1

Nucelotide position range

2173001-2186087

Substrate

exopolysaccharide

Loci

BT_1759-BT_1765

Species

Bacteroides thetaiotaomicron/818

Degradation or Biosynthesis

degradation

Cluster number

1

Gene name

Gene position

Gene type

Found by CGCFinder?

- 1 - 1833 (-) CAZyme: GH32 Yes
- 1963 - 3531 (-) CAZyme: GH32 Yes
- 3550 - 4935 (-) other Yes
- 4962 - 6674 (-) TC: gnl|TC-DB|C6Y217|8.A.46.1.3 Yes
- 6702 - 9827 (-) TC: gnl|TC-DB|Q45780|1.B.14.6.1 Yes
- 10127 - 10999 (+) other Yes
- 11204 - 13087 (-) CAZyme: GH32 Yes

PUL ID

PUL0203

PubMed

25841008, Appl Environ Microbiol. 2015 Jun 15;81(12):3973-83. doi: 10.1128/AEM.00149-15. Epub 2015 Apr 3.

Title

Differential Metabolism of Exopolysaccharides from Probiotic Lactobacilli by the Human Gut Symbiont Bacteroides thetaiotaomicron.

Author

Lammerts van Bueren A, Saraf A, Martens EC, Dijkhuizen L

Abstract

Probiotic microorganisms are ingested as food or supplements and impart positive health benefits to consumers. Previous studies have indicated that probiotics transiently reside in the gastrointestinal tract and, in addition to modulating commensal species diversity, increase the expression of genes for carbohydrate metabolism in resident commensal bacterial species. In this study, it is demonstrated that the human gut commensal species Bacteroides thetaiotaomicron efficiently metabolizes fructan exopolysaccharide (EPS) synthesized by probiotic Lactobacillus reuteri strain 121 while only partially degrading reuteran and isomalto/malto-polysaccharide (IMMP) alpha-glucan EPS polymers. B. thetaiotaomicron metabolized these EPS molecules via the activation of enzymes and transport systems encoded by dedicated polysaccharide utilization loci specific for beta-fructans and alpha-glucans. Reduced metabolism of reuteran and IMMP alpha-glucan EPS molecules may be due to reduced substrate binding by components of the starch utilization system (sus). This study reveals that microbial EPS substrates activate genes for carbohydrate metabolism in B. thetaiotaomicron and suggests that microbially derived carbohydrates provide a carbohydrate-rich reservoir for B. thetaiotaomicron nutrient acquisition in the gastrointestinal tract.