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Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/7140
Title: Bifidobacterium exopolysaccharides fermented by human microbiota
Authors: Salazar, Nuria; Gueimonde Fernández, Miguel; Hernández-Barranco, Ana María; Ruas-Madiedo, Patricia; González de los Reyes-Gavilán, Clara
Issue Date: 6-Jun-2008
Publisher: American Society for Microbiology
Citation: Applied and Environmental Microbiology 74(15): 4737-4745 (2008)
Abstract: Eleven exopolysaccharides (EPS) isolated from different human intestinal Bifidobacterium strains were tested in fecal slurry batch cultures and compared with glucose and the prebiotic inulin, for their ability to act as fermentable substrates for intestinal bacteria. During incubation, the increase of short chain fatty acids (SCFA) was considerably more pronounced in cultures with EPS, glucose, and inulin than in controls without carbohydrates added, indicating that the substrates assayed were fermented by intestinal bacteria. Shifts in molar proportions of SCFA during incubation with EPS and inulin caused a decrease on the acetic to propionic acids ratio, a possible indicator of the hypolipidemic effect of prebiotics,with the lowest values for this parameter obtained for EPS from the species B. longum, and from the strain B. pseudocatenulatum C52. This behaviour was contrary to that found with glucose, carbohydrate not considered as a prebiotic and for which a clear increase of this ratio was obtained during incubation. Quantitative real time PCR showed that EPS exerted a moderate bifidogenic effect, which was comparable for some polymers to inulin, but which was lower to that found for glucose. PCR-DGGE of 16S rDNA fragments using universal primers was employed to analyse microbial groups other than bifidobacteria. Changes in banding patterns during incubation with EPS indicated microbial rearrangements of Bacteroides and Escherichia coli relatives. Moreover, the use of EPS from B. pseudocatenulatum accounted, in fecal cultures from some individuals, for the prevalence of Desulfovibrio and Faecalibacterium prausnitzii whereas incubation with EPS from B. longum supported populations close to Anaerostipes, Prevotella, and/or Oscillospira. Thus, EPS synthesized by intestinal bifidobacteria could act as fermentable substrates for microorganisms in the human gut environment, modifying interactions among intestinal populations.
URI: http://hdl.handle.net/10261/7140
ISSN: 0099-2240
DOI: 10.1128/AEM.00325-08
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