Identification of Oligosaccharides in Feces of Breast-fed Infants and Their Correlation with the Gut Microbial Community
| Autor: | Zachery T. Lewis, Jennifer T. Smilowitz, Jasmine C.C. Davis, Lauren D. Wu, Carlito B. Lebrilla, Sadaf Nagshbandi, David A. Mills, Sarah M. Totten, Nina Kirmiz, Daniel Garrido, J. Bruce German, Julie O. Huang |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Biochemistry & Molecular Biology Glycan Bifidobacterium longum Glycoside Hydrolases Glycoconjugate Population Oligosaccharides Breast milk Biochemistry Mass Spectrometry Analytical Chemistry Feces 03 medical and health sciences fluids and secretions Bacterial Proteins Humans Glycoside hydrolase education Molecular Biology health care economics and organizations Nutrition Pediatric chemistry.chemical_classification Chromatography Liquid education.field_of_study Milk Human 030102 biochemistry & molecular biology biology Research Infant biology.organism_classification Gastrointestinal Microbiome Milk 030104 developmental biology chemistry biology.protein Bifidobacterium Digestive Diseases Bacteria Human Chromatography Liquid |
| Zdroj: | Molecular & cellular proteomics : MCP, vol 15, iss 9 |
| ISSN: | 1535-9476 |
| Popis: | Glycans in breast milk are abundant and found as either free oligosaccharides or conjugated to proteins and lipids. Free human milk oligosaccharides (HMOs) function as prebiotics by stimulating the growth of beneficial bacteria while preventing the binding of harmful bacteria to intestinal epithelial cells. Bacteria have adapted to the glycan-rich environment of the gut by developing enzymes that catabolize glycans. The decrease in HMOs and the increase in glycan digestion products give indications of the active enzymes in the microbial population. In this study, we quantitated the disappearance of intact HMOs and characterized the glycan digestion products in the gut that are produced by the action of microbial enzymes on HMOs and glycoconjugates from breast milk. Oligosaccharides from fecal samples of exclusively breast-fed infants were extracted and profiled using nanoLC-MS. Intact HMOs were found in the fecal samples, additionally, other oligosaccharides were found corresponding to degraded HMOs and non-HMO based compounds. The latter compounds were fragments of N-glycans released through the cleavage of the linkage to the asparagine residue and through cleavage of the chitobiose core of the N-glycan. Marker gene sequencing of the fecal samples revealed bifidobacteria as the dominant inhabitants of the infant gastrointestinal tracts. A glycosidase from Bifidobacterium longum subsp. longum was then expressed to digest HMOs in vitro, which showed that the digested oligosaccharides in feces corresponded to the action of glycosidases on HMOs. Similar expression of endoglycosidases also showed that N-glycans were released by bacterial enzymes. Although bifidobacteria may dominate the gut, it is possible that specific minority species are also responsible for the major products observed in feces. Nonetheless, the enzymatic activity correlated well with the known glycosidases in the respective bacteria, suggesting a direct relationship between microbial abundances and catabolic activity. |
| Databáze: | OpenAIRE |
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