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Human Milk Oligosaccharides (human + milk_oligosaccharide)

Distribution by Scientific Domains

Life Sciences	83%

Selected Abstracts

Assessment of the Two Helicobacter pylori ,-1,3-Fucosyltransferase Ortholog Genes for the Large-Scale Synthesis of LewisX Human Milk Oligosaccharides by Metabolically Engineered Escherichia coli

BIOTECHNOLOGY PROGRESS, Issue 2 2004
Claire Dumon
We previously described a bacterial fermentation process for the in vivo conversion of lactose into fucosylated derivatives of lacto- N -neotetraose Gal(,1,4)GlcNAc(,1,3)Gal(,1,4)Glc (LNnT). The major product obtained was lacto- N -neofucopentaose-V Gal(,1,4)GlcNAc(,1,3)Gal(,1,4)[Fuc(,1,3)]Glc, carrying fucose on the glucosyl residue of LNnT. Only a small amount of oligosaccharides fucosylated on N -acetylglucosaminyl residues and thus carrying the LewisX group (LeX) was also produced. We report here a fermentation process for the large-scale production of LeX oligosaccharides. The two fucosyltransferase genes futA and futB of Helicobacter pylori (strain 26695) were compared in order to optimize fucosylation in vivo. futA was found to provide the best activity on the LNnT acceptor, whereas futB expressed a better LeX activity in vitro. Both genes were expressed to produce oligosaccharides in engineered Escherichia coli ( E. coli) cells. The fucosylation pattern of the recombinant oligosaccharides was closely correlated with the specificity observed in vitro, FutB favoring the formation of LeX carrying oligosaccharides. Lacto- N -neodifucohexaose-II Gal(,1,4)[Fuc(,1,3)]GlcNAc(,1,3)Gal(,1,4)[Fuc(,1,3)]Glc represented 70% of the total oligosaccharide amount of futA -on-driven fermentation and was produced at a concentration of 1.7 g/L. Fermentation driven by futBled to equal amounts of both lacto- N -neofucopentaose-V and lacto- N -neofucopentaose-II Gal(,1,4)[Fuc(,1,3)]GlcNAc(,1,3)Gal(,1,4)Glc, produced at 280 and 260 mg/L, respectively. Unexpectedly, a noticeable proportion (0.5 g/L) of the human milk oligosaccharide 3-fucosyllactose Gal(,1,4)[Fuc(,1,3)]Glc was produced in futA -on-driven fermentation, underlining the activity of fucosyltransferase FutA in E.coli and leading to a reassessment of its activity on lactose. All oligosaccharides produced by the products of both fut genes were natural compounds of human milk. [source]

CE-LIF-MSn profiling of oligosaccharides in human milk and feces of breast-fed babies

ELECTROPHORESIS, Issue 7 2010
Simone Albrecht
Abstract Mixtures of the complex human milk oligosaccharides (HMOs) are difficult to analyze and gastrointestinal bioconversion products of HMOs may complicate analysis even more. Their analysis, therefore, requires the combination of a sensitive and high-resolution separation technique with a mass identification tool. This study introduces for the first time the hyphenation of CE with an electrospray mass spectrometer, capable to perform multiple MS analysis (ESI-MSn) for the separation and characterization of HMOs in breast milk and feces of breast-fed babies. LIF was used for on- and off-line detections. From the overall 47 peaks detected in off-line CE-LIF electropherograms, 21 peaks could be unambiguously and 11 peaks could be tentatively assigned. The detailed structural characterization of a novel lacto- N -neo-tetraose isomer and a novel lacto- N -fucopentaose isomer was established in baby feces and pointed to gastrointestinal hydrolysis of higher-Mw HMOs. CE-LIF-ESI-MSn presents, therefore, a useful tool which contributes to an advanced understanding on the fate of individual HMOs during their gastrointestinal passage. [source]

In vitro fermentability of human milk oligosaccharides by several strains of bifidobacteria

MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 11 2007
Robert E. Ward
Abstract This study was conducted to investigate the catabolism and fermentation of human milk oligosaccharides (HMO) by individual strains of bifidobacteria. Oligosaccharides were isolated from a pooled sample of human milk using solid-phase extraction, and then added to a growth medium as the sole source of fermentable carbohydrate. Of five strains of bifidobacteria tested (Bifidobacterium longum biovar infantis, Bifidobacterium bifidum, Bifidobacterium longum biovar longum, Bifidobacterium breve, and Bifidobacterium adolescentis), B. longum bv. infantis grew better, achieving triple the cell density then the other strains. B. bifidum did not reach a high cell density, yet generated free sialic acid, fucose and N-acetylglucosamine in the media, suggesting some capacity for HMO degradation. Thin layer chromatography profiles of spent fermentation broth suggests substantial degradation of oligosaccharides by B. longum bv. infantis, moderate degradation by B. bifidum and little degradation by other strains. While all strains were able to individually ferment two monosaccharide constituents of HMO, glucose and galactose, only B. longum bv. infantis and B. breve were able to ferment glucosamine, fucose and sialic acid. These results suggest that as a potential prebiotic, HMO may selectively promote the growth of certain bifidobacteria strains, and their catabolism may result in free monosaccharides in the colonic lumen. [source]

Reproducing the bifidogenic effect of human milk in formula-fed infants: Why and how?

ACTA PAEDIATRICA, Issue 2005
Guido E Moro
Abstract Awareness of the key role of the intestinal microflora in the generation of the immunophysiological regulation and in the defence against pathogenic agents has attracted our interest in ways of manipulating the microbiota to improve health. Dietary modulation of the intestinal microflora is today one of the main topics of interest in the nutritional sciences. Performing this modulation in the neonatal or early infancy period, when immunological programming takes place, is a relatively new concept. Fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) are prebiotics whose bifidogenic activity has been proven in adults. However, only recently have they been combined in infant formulas to reproduce the prebiotic effect of human milk oligosaccharides. In two consecutive trials, it has been demonstrated that supplementation of infant formulas with a mixture of GOS and FOS modified the fecal flora of term and preterm infants, stimulating the growth of Bifidobacteria. In the trial with term infants, the bifidogenic effect of the prebiotic mixture was dose dependent and there was also a significant increase in the number of Lactobacilli in the supplemented group. These findings offer a promising horizon for the early prevention of allergy and infections in infants. [source]