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Lipids of Histoplasma Capsulatum
Published in Rajendra Prasad, Mahmoud A. Ghannoum, Lipids of Pathogenic Fungi, 2017
Oligosaccharide-VI was converted to partially methylated alditol acetates and the products were analyzed by gas chromatography/mass spectrometry. Four peaks were evident in the mass spectrum of oligosaccharide-VI. Peak I was identified as penta-O-methyl-mono-O-acetylinositol. The ion profile of peak II indicated that it was l,5-di-0-acetyl-2,3,4,6-tetra-0-methyl-mannitol, or an unsubstituted mannopyranoside. Peak IV had the same retention time and mass spectrum as authentic 2,4-di-0-methyl-l,3,5,6-tetra-O-acetylmannitol.
Enzymatically synthesized exopolysaccharide of a probiotic strain Leuconostoc mesenteroides NTM048 shows adjuvant activity to promote IgA antibody responses
Published in Gut Microbes, 2021
Chiaki Matsuzaki, Yukari Nakashima, Ikuto Endo, Yusuke Tomabechi, Yasuki Higashimura, Saki Itonori, Koji Hosomi, Jun Kunisawa, Kenji Yamamoto, Keiko Hisa
To elucidate the linkage pattern of glucan samples, we prepared partially methylated alditol acetate derivatives and analyzed them using GC-MS (Table 2). S-glucans from Gtf1 and LEUM1747 harbored 6-linked glucose units in a polymer backbone and exhibited 10–12% branching with 3,6-linked residues. On the other hand, 3-linked and 6-linked glucose with 3,6-linked branching residues were detected in both S- and P-glucans from Gtf2 and LEUM1752, but the 3-linkage/6-linkage ratio was different. For S-glucan, the ratio of 3-linkage was lower than that of 6-linkage, whereas the former was higher than the latter in P-glucan. Glucans mainly harboring α-1,3-linked glucose are generally water-insoluble, whereas glucans consisting of a high level of α-1,6-linked glucose are soluble in water.36,38,39 A high ratio of 1,3-linked glucose might cause precipitation of P-glucans.
Characterization of the EPS from a thermophilic corrosive consortium
Published in Biofouling, 2019
J. Atalah, L. Blamey, I. Gelineo-Albersheim, J. M. Blamey
Two separate glycosyl composition analyses were performed, based on previously described methods (York et al. 1986; Gatlin et al. 2013). The first analysis was performed using gas chromatography/mass spectroscopy (GC/MS) of the per-O-trimethylsilyl (TMS) derivatives of the monosaccharide methyl glycosides. The second glycosyl composition analysis was done using GC/MS of partially methylated alditol acetates. Both methods used myo-inositol as an internal standard. The standard mix of known monosaccharides underwent the same procedural steps and were used as a reference for monosaccharide retention time calculation. Both methods are described below.
Mass spectrometric analysis of glycosylated viral proteins
Published in Expert Review of Proteomics, 2018
Electron (or electron-impact) ionization involves bombardment of the sample molecules in the gas phase causing them to both ionize by loss of an electron and to fragment. The technique can conveniently be combined with gas–liquid chromatography (gas chromatography/mass spectrometry [GC/MS]) for mixture analysis. Problems with volatility limit the use of the technique to monosaccharides or small oligosaccharides but, even then, derivatization is necessary to make them sufficiently volatile. Although not applicable to N-glycans directly, the technique is still useful because the newer ionization techniques of matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) that are capable of ionizing these compounds do not provide information on the nature of the constituent monosaccharides. Consequently, this information must be obtained by orthogonal techniques such as GC/MS following hydrolysis or by use of exoglycosidases. One manifestation of the use of GC/MS is methylation or linkage analysis which provides information both on the nature of the monosaccharides and on which positions are involved in linkage. There are numerous variations of this technique that was developed in the late 1960s [17,18], reviewed by Hanisch [19], but essentially they consist of permethylation of the glycan [20–22], acid hydrolysis to release the constituent monosaccharides which are then derivatized with another reagent to label the newly released hydroxyl groups. Acetylation is a favorite method to give permethylated alditol acetates which are identified by GC/MS. Reduction of the reducing end monosaccharide with a deuterated reagent enables that monosaccharide to be easily identified. Although the method provides information on the nature of the monosaccharide and the positions involved in linkage, it does not provide information on what was attached at each position. The method has been used many times for analysis of viral N-glycans, such as those from Friend murine leukemia virus (see references in Table 5), hepatitis B surface antigens [23], HIV [24], and Newcastle disease virus [25].