Advanced Characterization of Biofunctional Human Milk Oligosaccharides by Mass Spectrometry and Complementary Methods

10.33540/897 ◽  
2021 ◽  
Author(s):  
◽  
Marko Mank
Keyword(s):  
Mass Spectrometry ◽  
Human Milk ◽  
Advanced Characterization ◽  
Human Milk Oligosaccharides ◽  
Milk Oligosaccharides ◽  
Complementary Methods

scholarly journals New strategies for profiling and characterization of human milk oligosaccharides

Glycobiology ◽  
2020 ◽  
Vol 30 (10) ◽  
pp. 774-786 ◽  
Author(s):  
Sara Porfirio ◽  
Stephanie Archer-Hartmann ◽  
G Brett Moreau ◽  
Girija Ramakrishnan ◽  
Rashidul Haque ◽  
...  
Keyword(s):  
Breast Milk ◽  
Human Milk ◽  
Milk Composition ◽  
Human Breast Milk ◽  
Human Milk Oligosaccharides ◽  
Bacterial Strains ◽  
Milk Oligosaccharides ◽  
Vast Number ◽  
The Impact

Abstract Human breast milk is an incredibly rich and complex biofluid composed of proteins, lipids and complex carbohydrates, including a diverse repertoire of free human milk oligosaccharides (HMOs). Strikingly, HMOs are not digested by the infant but function as prebiotics for bacterial strains associated with numerous benefits. Considering the broad variety of beneficial effects of HMOs, and the vast number of factors that affect breast milk composition, the analysis of HMO diversity and complexity is of utmost relevance. Using human milk samples from a cohort of Bangladeshi mothers participating in a study on malnutrition and stunting in children, we have characterized breast milk oligosaccharide composition by means of permethylation followed by liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-MS/MS) analysis. This approach identified over 100 different glycoforms and showed a wide diversity of milk composition, with a predominance of fucosylated and sialylated HMOs over nonmodified HMOs. We observed that these samples contain on average 80 HMOs, with the highest permethylated masses detected being >5000 mass units. Here we report an easily implemented method developed for the separation, characterization and relative quantitation of large arrays of HMOs, including higher molecular weight sialylated HMOs. Our ultimate goal is to create a simple, high-throughput method, which can be used for full characterization of sialylated and/or fucosylated HMOs. These results demonstrate how current analytical techniques can be applied to characterize human milk composition, providing new tools to help the scientific community shed new light on the impact of HMOs during infant development.

scholarly journals Oligosaccharides Released from Milk Glycoproteins Are Selective Growth Substrates for Infant-Associated Bifidobacteria

2016 ◽  
Vol 82 (12) ◽  
pp. 3622-3630 ◽  
Author(s):  
Sercan Karav ◽  
Annabelle Le Parc ◽  
Juliana Maria Leite Nobrega de Moura Bell ◽  
Steven A. Frese ◽  
Nina Kirmiz ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Milk ◽  
Bifidobacterium Longum ◽  
Bovine Milk ◽  
Selective Growth ◽  
Whey Protein Concentrate ◽  
Human Milk Oligosaccharides ◽  
Milk Oligosaccharides ◽  
Content Type ◽  
Growth Substrates

ABSTRACTMilk, in addition to nourishing the neonate, provides a range of complex glycans whose construction ensures a specific enrichment of key members of the gut microbiota in the nursing infant, a consortium known as the milk-oriented microbiome. Milk glycoproteins are thought to function similarly, as specific growth substrates for bifidobacteria common to the breast-fed infant gut. Recently, a cell wall-associated endo-β-N-acetylglucosaminidase (EndoBI-1) found in various infant-borne bifidobacteria was shown to remove a range of intactN-linked glycans. We hypothesized that these released oligosaccharide structures can serve as a sole source for the selective growth of bifidobacteria. We demonstrated that EndoBI-1 releasedN-glycans from concentrated bovine colostrum at the pilot scale. EndoBI-1-releasedN-glycans supported the rapid growth ofBifidobacterium longumsubsp.infantis(B. infantis), a species that grows well on human milk oligosaccharides, but did not support growth ofBifidobacterium animalissubsp.lactis(B. lactis), a species which does not. Conversely,B. infantisATCC 15697 did not grow on the deglycosylated milk protein fraction, clearly demonstrating that the glycan portion of milk glycoproteins provided the key substrate for growth. Mass spectrometry-based profiling revealed thatB. infantisconsumed 73% of neutral and 92% of sialylatedN-glycans, whileB. lactisdegraded only 11% of neutral and virtually no (<1%) sialylatedN-glycans. These results provide mechanistic support thatN-linked glycoproteins from milk serve as selective substrates for the enrichment of infant-associated bifidobacteria capable of carrying out the initial deglycosylation. Moreover, releasedN-glycans were better growth substrates than the intact milk glycoproteins, suggesting that EndoBI-1 cleavage is a key initial step in consumption of glycoproteins. Finally, the variety ofN-glycans released from bovine milk glycoproteins suggests that they may serve as novel prebiotic substrates with selective properties similar to those of human milk oligosaccharides.IMPORTANCEIt has been previously shown that glycoproteins serve as growth substrates for bifidobacteria. However, which part of a glycoprotein (glycans or polypeptides) is responsible for this function was not known. In this study, we used a novel enzyme to cleave conjugatedN-glycans from milk glycoproteins and tested their consumption by various bifidobacteria. The results showed that the glycans selectively stimulated the growth ofB. infantis, which is a key infant gut microbe. The selectivity of consumption of individualN-glycans was determined using advanced mass spectrometry (nano-liquid chromatography chip–quadrupole time of flight mass spectrometry [nano-LC-Chip-Q-TOF MS]) to reveal thatB. infantiscan consume the range of glycan structures released from whey protein concentrate.

scholarly journals Comparison of Different Labeling Techniques for the LC-MS Profiling of Human Milk Oligosaccharides

2021 ◽  
Vol 9 ◽  
Author(s):  
Yinzhi Lang ◽  
Yongzhen Zhang ◽  
Chen Wang ◽  
Limei Huang ◽  
Xiaoxiao Liu ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Milk ◽  
Biological Activities ◽  
Complex Mixture ◽  
Molecular Ions ◽  
Quantitative Detection ◽  
Human Milk Oligosaccharides ◽  
Combination Strategy ◽  
Milk Oligosaccharides ◽  
Chromatography Mass Spectrometry

Human milk oligosaccharides (HMOs) exhibit various biological activities for infants, such as serving as prebiotics, blocking pathogens, and aiding in brain development. HMOs are a complex mixture of hetero-oligosaccharides that are generally highly branched, containing multiple structural isomers and no intrinsic chromophores, presenting a challenge to both their resolution and quantitative detection. While liquid chromatography-mass spectrometry (LC-MS) has become the primary strategy for analysis of various compounds, the very polar and chromophore-free properties of native glycans hinder their separation in LC and ionization in MS. Various labeling approaches have been developed to achieve separation of glycans with higher resolution and greater sensitivity of detection. Here, we compared five commonly used labeling techniques [by 2-aminobenzamide, 2-aminopyridine, 2-aminobenzoic acid (2-AA), 2,6-diaminopyridine, and 1-phenyl-3-methyl-5-pyrazolone] for analyzing HMOs specifically under hydrophilic-interaction chromatography-mass spectrometry (HILIC-MS) conditions. The 2-AA labeling showed the most consistent deprotonated molecular ions, the enhanced sensitivity with the least structural selectivity, and the sequencing-informative tandem MS fragmentation spectra for the widest range of HMOs; therefore, this labeling technique was selected for further optimization under the porous graphitized carbon chromatography-mass spectrometry (PGC-MS) conditions. The combination strategy of 2-AA labeling and PGC-MS techniques provided online decontamination (removal of excess 2-AA, salts, and lactose) and resolute detection of many HMOs, enabling us to characterize the profiles of complicated HMO mixtures comprehensively in a simple protocol.

Methods for the quantitation of human milk oligosaccharides in bacterial fermentation by mass spectrometry

2007 ◽  
Vol 361 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Milady R. Ninonuevo ◽  
Robert E. Ward ◽  
Riccardo G. LoCascio ◽  
J. Bruce German ◽  
Samara L. Freeman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Human Milk ◽  
Human Milk Oligosaccharides ◽  
Milk Oligosaccharides ◽  
Bacterial Fermentation

scholarly journals Enzymatic Cascades for Tailored 13C6 and 15N Enriched Human Milk Oligosaccharides

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3482 ◽  
Author(s):  
Fischöder ◽  
Cajic ◽  
Grote ◽  
Heinzler ◽  
Reichl ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Human Milk ◽  
Absolute Quantification ◽  
Human Milk Oligosaccharides ◽  
Milk Oligosaccharides ◽  
Enzymatic Production ◽  
Flight Mass Spectrometry ◽  
Enzymatic Cascades ◽  
Biological Mixtures

Several health benefits, associated with human milk oligosaccharides (HMOS), have been revealed in the last decades. Further progress, however, requires not only the establishment of a simple "routine" method for absolute quantification of complex HMOS mixtures but also the development of novel synthesis strategies to improve access to tailored HMOS. Here, we introduce a combination of salvage-like nucleotide sugar-producing enzyme cascades with Leloir-glycosyltransferases in a sequential pattern for the convenient tailoring of stable isotope-labeled HMOS. We demonstrate the assembly of [13C6]galactose into lacto-N- and lacto-N-neo-type HMOS structures up to octaoses. Further, we present the enzymatic production of UDP-[15N]GlcNAc and its application for the enzymatic synthesis of [13C6/15N]lacto-N-neo-tetraose for the first time. An exemplary application was selected—analysis of tetraose in complex biological mixtures—to show the potential of tailored stable isotope reference standards for the mass spectrometry-based quantification, using matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) as a fast and straightforward method for absolute quantification of HMOS. Together with the newly available well-defined tailored isotopic HMOS, this can make a crucial contribution to prospective research aiming for a more profound understanding of HMOS structure-function relations.

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