Interaction between reacetylated chitosan and albumin in alcalescent media.

Interaction of chitosan and its derivatives with proteins of animal blood at blood pH relevant conditions is of a particular interest for construction of antimicrobial chitosan/protein-based drug delivery systems. In this work, the interaction of a series of N-reacetylated oligochitosans (RA-CHI) having M of 10-12 kDa and differing in the degree of acetylation (DA 19, 24, and 40 %) with bovine serum albumin (BSA) in alkalescent media is described in first. It is shown that RA-CHI forms soluble complexes with BSA in solutions with pH 7.

Identifying human milk glycans that inhibit norovirus binding using surface plasmon resonance.

Human milk glycans inhibit binding between norovirus and its host glycan receptor; such competitive inhibition by human milk glycans is associated with a reduced risk of infection. The relationship between the presence of specific structural motifs in the human milk glycan and its ability to inhibit binding by specific norovirus strains requires facile, accurate and miniaturized-binding assays. Toward this end, a high-throughput biosensor platform was developed based on surface plasmon resonance imaging (SPRi) of glycan microarrays.

Analysis of chain and blood group type and branching pattern of sialylated oligosaccharides by negative ion electrospray tandem mass spectrometry.

We previously reported sequence determination of neutral oligosaccharides by negative ion electrospray tandem mass spectrometry on a quadrupole-orthogonal time-of-flight instrument with high sensitivity and without the need of derivatization. In the present report, we extend our strategies to sialylated oligosaccharides for analysis of chain and blood group types together with branching patterns. A main feature in the negative ion mass spectrometry approach is the unique double glycosidic cleavage induced by 3-glycosidic substitution, producing characteristic D-type fragments which can be used to distinguish the type 1 and type 2 chains, the blood group related Lewis determinants, 3,6-disubstituted core branching patterns, and to assign the structural details of each of the branches.

Structural determination of novel lacto-N-decaose and its monofucosylated analogue from human milk by electrospray tandem mass spectrometry and 1H NMR spectroscopy.

We have isolated and characterised two neutral oligosaccharides, one nonfucosylated and the other monofucosylated, from human milk that are based on the doubly branched lacto-N-decaose core. Their structures have been determined by a combined use of electrospray tandem mass spectrometry (ES-MS/MS) and NMR spectroscopy. The sequences of the three branches resulted from the double-branching, including the identity and location of the blood-group-related Lewis determinant and partial linkages, were elucidated by the unique method of high sensitivity negative-ion ES-MS/MS analysis.

Determination by electrospray mass spectrometry and 1H-NMR spectroscopy of primary structures of variously fucosylated neutral oligosaccharides based on the iso-lacto-N-octaose core.

We have isolated a nonfucosylated and three variously fucosylated neutral oligosaccharides from human milk that are based on the iso-lacto-N-octaose core. Their structures were characterized by the combined use of electrospray mass spectrometry (ES-MS) and NMR spectroscopy. The branching pattern and blood group-related Lewis determinants, together with partial sequences and linkages of these oligosaccharides, were initially elucidated by high-sensitivity ES-MS/MS analysis, and then their full structure assignment was completed by methylation analysis and 1H-NMR.

An investigation of the interactions of E-selectin with fuco-oligosaccharides of the blood group family.

This investigation is concerned with assignments of Lewis(a) (Le(a)) and Le(x) analogs on linear and branched di- to hexasaccharide backbones as components of the recognition motifs for E-selectin. The influence of the location of fucose residue(s) was investigated using 14 structurally defined and variously fucosylated oligosaccharides in biotinylated form or as neoglycolipids in static binding assays, in microwells, and on thin-layer chromatograms. Results of the two assay systems were in agreement overall and showed that the recognition motifs for E-selectin include 4-fucosyl-lacto (Le(a)) and 3-fucosyl-neo-lacto (Le(x)) sequences strictly at capping positions and not Le(x) at an internal position as a part of VIM-2 antigen sequence.