Structures of the oligosaccharides isolated from milk of the platypus

Eight major oligosaccharides were isolated from platypus milk. By sequential exoglycosidase digestion and methylation study, their structures were elucidated as shown in Fig. 9 of this paper. The characteristics feature of the platypus milk oligosaccharides is that lacto-N-neotetraose and lacto-N-neohexaose are the major cores in contrast to human milk oligosaccharides in which lacto-N-tetraose and lacto-N-hexaose are found as the major core.     

Structures of the neutral oligosaccharides isolated from A-active human gastric mucin

Alkaline borohydride reductive cleavage of the mucin, purified from gastric aspirates of the secretors with blood group A, resulted in a heterogeneous population of neutral (79.7%) and acidic (20.3%) oligosaccharide alditols. Nine oligosaccharides (I-IX), ranging from 6 to 15 sugar units, have been purified from the neutral oligosaccharide fraction. Based on the results of immunological assays, sugar composition, degradation with specific exoglycosidases, and methylation analyses, we propose the following structures for these oligosaccharides: (sequence in text)     

Structural analysis of three sulfated oligosaccharides isolated from human milk

The structures of two sulfated octasaccharides and one sulfated nonasaccharide isolated from human milk have been investigated. Using 13C and 1H NMR spectroscopy and ESMS, the following structures 1-3 were established: [formula: see text].     

Structures of novel sialylated O-linked oligosaccharides isolated from human erythrocyte glycophorins

The O-linked oligosaccharides attached to human erythrocyte glycophorins were extensively characterized. In addition to the previously described disialylated tetrasaccharide, NeuNAc alpha 2----3Gal beta 1----3 (Neu-NAc alpha 2----6)GalNAcOH and monosialylated trisaccharide, NeuNAc alpha 2----3Gal beta 1----3GalNAcOH, novel trisialylated oligosaccharides were isolated. Methylation analysis, fast atom bombardment-mass spectrometry, and enzymatic degradation were used to elucidate the following novel structures: formula; see text: These results suggest that O-linked oligosaccharides with a disialosyl group, NeuNAc alpha 2----8NeuNAc alpha 2----, may be present in various tissues.     

Fractionation and characterization of acidic oligosaccharides and glycopeptides from normal and pathological urines

A general procedure is described for the isolation of urinary acidic oligosaccharides and glycopeptides resulting from catabolism of glycoproteins. This procedure has been applied to normal urine and to urine from patients with diseases of the metabolism, including mucolipidosis and fucosidosis.     

Characterization of Escherichia coli strains isolated from urine of secretors and non-secretors

Strains of Escherichia coli isolated from urine of secretors (242) and non-secretors (121) were compared for their serotype and their ability to express mannose-sensitive (MS) haemagglutinins and mannose-resistant (MR) haemagglutinins and to produce haemolysin. The results of the survey refuted our hypothesis that strains with characteristics associated with virulence, those with MR haemagglutinins and/or haemolysins, would be isolated more frequently from non-secretors. MR haemagglutinins were detected among 36.4% of isolates from secretors and 27.3% of isolates from non-secretors. Haemolysin production was detected among 19.8% of isolates from secretors and 12.5% of isolates from non-secretors. Both MR haemagglutinins and haemolysin were detected only on 12.4% of strains from secretors and 6.7% of strains from non-secretors.     

Structures of oligosaccharides on beta-galactosidase from Aspergillus oryzae

The carbohydrate portions of beta-galactosidase from Aspergillus oryzae were found to be composed of two types of sugar chains. They were released equally well with endo-beta-N-acetylglucosaminidase H, but were distinct in their chain length. The long sugar chains (fraction I), corresponding to 4% of the total carbohydrate chains, were composed of galactomannan-type oligosaccharides, which consisted of mannose, galactose, glucose, and glucosamine in the molar ratios of 30.0, 16.4, 1.4, and 2.1 per mol of aspartic acid, respectively. The short sugar chains (fraction II), corresponding to 96% of the total carbohydrate chains, consisted of mannose, galactose, glucose, and glucosamine in the molar ratios of 9.4, 0.6, 0.3, and 1.7 per mol of aspartic acid, respectively. Both types of sugar chains were fractionated into neutral and acidic subfractions. The neutral subfraction of fraction I (I-N), corresponding to 1% of the total carbohydrate chains, was very heterogeneous in length and was resistant to digestion with alpha-mannosidase and beta-galactosidase. The neutral subfraction of fraction II (II-N), corresponding to 91% of the total carbohydrate, was composed of a mixture of oligosaccharides with oligomanneoside chains (Mann GlcNAcol). The major components were similar to high mannose-type oligosaccharides of mammalian origin in their composition and size (n = 5-9). However, digestion of II-N with alpha 1,2-mannosidase produced considerable amounts of Man6GlcNAcol, an unusual product in the case of high mannose-type oligosaccharides of mammalian origin, in addition to the common one, Man5GlcNAcol.     

Characterization of Escherichia coli strains isolated from urine of secretors and non-secretors

Abstract Strains of Escherichia coli isolated from urine of secretors (242) and non-secretors (121) were compared for their serotype and their ability to express mannose-sensitive (MS) haemagglutinins and mannose-resistant (MR) haemagglutinins and to produce haemolysin. The results of the survey refuted our hypothesis that strains with characteristics associated with virulence, those with MR haemagglutinins and/or haemolysins, would be isolated more frequently from non-secretors. MR haemagglutinins were detected among 36.4% of isolates from secretors and 27.3% of isolates from non-secretors. Haemolysin production was detected among 19.8% of isolates from secretors and 12.5% of isolates from non-secretors. Both MR haemagglutinins and haemolysin were detected only on 12.4% of strains from secretors and 6.7% of strains from non-secretors.     

Structural characterization and immunological activities of the water-soluble oligosaccharides isolated from the Panax ginseng roots

Water-soluble ginseng oligosaccharides (designated as WGOS) with a degree of polymerization ranging from 2 to 10 were obtained from warm-water extract of Panax ginseng roots, and fractionated into five purified fractions (i.e., WGOS-0, WGOS-1, WGOS-2, WGOS-3, and WGOS-4) by gel-filtration chromatography. In order to ascertain the monosaccharide residues in the WGOS, a technique that combines acid hydrolysis and high-performance liquid chromatography was employed. It was found that only glucose residues were present in the WGOS. Fourier transform infrared spectroscopy and electrospray ionization tandem mass spectrometry provided the sequence, linkage, and configuration information. It is noteworthy that α-Glcp-(1?→?6)-α-Glcp, α-Glcp-(1?→?6)-α-Glcp-(1?→?4)-α-Glcp, α-Glcp-(1?→?6)-α-Glcp-(1?→?6)-α-Glcp-(1?→?4)-α-Glcp, and other six malto-oligosaccharides (i.e., maltopentaose, maltohexaose, maltoheptaose, maltooctaose, maltononaose, and maltodecaose) were detected in ginseng. Preliminary immunological tests in vitro indicated that WGOS were potent B and T-cell stimulators and WGOS-1 has the highest immunostimulating effect on lymphocyte proliferation among those purified fractions. It is hoped that the WGOS will be developed into functional food or medicine.     

Structures of wall heterogalactomannans isolated from three genera of entomopathogenic fungi

O-linked heterogalactomannans with similar structural features have been purified from the fungal walls of the entomopathogenic fungi Lecanicillium muscarium, Beauveria bassiana, Beauveriabrongniartii, and Cordyceps sphingum. Their composition and structure have been determined using acid hydrolysis, methylation analysis, gas-liquid chromatography-mass spectrometry (GC-MS) and Nuclear magnetic resonance spectroscopy (NMR). All structures have an α-(1→6)-mannose backbone, but one of the two strains of L. muscarium included in this study contained an acidic heterogalactomannan instead of the neutral polysaccharide isolated in the rest of the species analyzed. Sequence analysis of the internal transcribed spacer (ITS) region of this strain indicated that it belongs to the related genus Simplicillium, displaying low identity (83%) with the closest Lecanicillium species. This is a new demonstration of the structural diversity of fungal wall heteromannans and validates their interest as chemotaxonomic markers. The production of a pullulan-like extracellular polysaccharide in strain CBS 413.70C of L. muscarium is also reported.     

Structures and biological activities of three synaptic antagonists from orb weaver spider venom

The venom of Argiope aurantia, an orb weaver spider, contains a mixture of low molecular weight "argiotoxins", which block neuromuscular transmission in insects. Complete structure elucidation of three argiotoxins reveals common features; a hydrophilic, basic domain of arginine, a polyamine and asparagine is connected to an aromatic moiety contributed either by 4-hydroxyindole-3-acetic acid or 2,4-dihydroxyphenylacetic acid. Structural assignments of two argiotoxins are verified by chemical synthesis. The argiotoxins cause reversible paralysis when injected into insects and this is correlated with a stimulus-dependent inhibition of skeletal neuromuscular transmission at submicromolar concentrations.     

Structures of asparagine linked oligosaccharides of immunoglobulins (IgY) isolated from egg-yolk of Japanese quail

Structures of the Asn linked oligosaccharides of quail egg-yolk immunoglobulin (IgY) were determined in this study. Asn linked oligosaccharides were cleaved from IgY by hydrazinolysis and labelled withp-aminobenzoic acid ethyl ester (ABEE) afterN-acetylation. The ABEE labelled oligosaccharides were then fractionated by a combination of Concanavalin A-agarose column chromatography and anion exchange, normal phase and reversed phase HPLC before their structures were determined by sequential exoglycosidase digestion, methylation analysis, HPLC, and 500 MHz¹H-NMR spectroscopy. Quail IgY contained only neutral oligosaccharides of the following categories: the glucosylated oligomannose type (0.6%, Glc1-3Glc1-3Man₉GlcNAc₂; 35.6%, Glc1-3Man_7–9GlcNAc₂). oligomannose type (15.0%, with the structure Man_5–9GlcNAc₂) and biantennary complex type with core structures of-Man1-3(-Man1-6)Man1-4GlcNAc1-4GlcNAc (9.9%),-Man1-3(GlcNAc1-4)(-Man1-6)Man1-4GlcNAc1-4GlcNAc (25.1%) and-Man1-3(GlcNAc1-4)(-Man1-6)Man1-4GlcNAc1-4(Fuc1-6)GlcNAc (11.4%). Although never found in mammalian proteins, glucosylated oligosaccharides (Glc₁Man_7–9GlcNAc₂) have been located previously in hen IgY.Abbreviations IgG, IgM, IgA, IgY immunoglobulin G, M, A and Y, respectively - ABEE p-aminobenzoic acid ethyl ester     

Evolution of milk oligosaccharides and lactose: a hypothesis

Mammalian milk or colostrum contains up to 10% of carbohydrate, of which free lactose usually constitutes more than 80%. Lactose is synthesized within lactating mammary glands from uridine diphosphate galactose (UDP-Gal) and glucose by a transgalactosylation catalysed by a complex of β4-galactosyltransferase and α-lactalbumin (α-LA). α-LA is believed to have evolved from C-type lysozyme. Mammalian milk or colostrum usually contains a variety of oligosaccharides in addition to free lactose. Each oligosaccharide has a lactose unit at its reducing end; this unit acts as a precursor that is essential for its biosynthesis. It is generally believed that milk oligosaccharides act as prebiotics and also as receptor analogues that act as anti-infection factors. We propose the following hypothesis. The proto-lacteal secretions of the primitive mammary glands of the common ancestor of mammals contained fat and protein including lysozyme, but no lactose or oligosaccharides because of the absence of α-LA. When α-LA first appeared as a result of its evolution from lysozyme, its content within the lactating mammary glands was low and lactose was therefore synthesized at a slow rate. Because of the presence of glycosyltransferases, almost all of the nascent lactose was utilized for the biosynthesis of oligosaccharides. The predominant saccharides in the proto-lacteal secretions or primitive milk produced by this common ancestor were therefore oligosaccharides rather than free lactose. Subsequent to this initial period, the oligosaccharides began to serve as anti-infection factors. They were then recruited as a significant energy source for the neonate, which was achieved by an increase in the synthesis of α-LA. This produced a concomitant increase in the concentration of lactose in the milk, and lactose therefore became an important energy source for most eutherians, whereas oligosaccharides continued to serve mainly as anti-microbial agents. Lactose, in addition, began to act as an osmoregulatory molecule, controlling the milk volume. Studies on the chemical structures of the milk oligosaccharides of a variety of mammalian species suggest that human milk or colostrum is unique in that oligosaccharides containing lacto-N-biose I (LNB) (Gal(β1 → 3)GlcNAc, type I) predominate over those containing N-acetyllactosamine (Gal(β1 → 4)GlcNAc, type II), whereas in other species only type II oligosaccharides are found or else they predominate over type I oligosaccharides. It can be hypothesized that this feature may have a selective advantage in that it may promote the growth of beneficial colonic bacteria, Bifidobacteria, in the human infant colon.     

Structures of galactose-containing oligosaccharides of alpha-mannosidase from porcine kidney

Oligosaccharides of a non-oligomannoside type were released from porcine alpha-mannosidase by hydrazinolysis, and were fractionated into at least 15 homogeneous oligosaccharides. Most of them are oligosaccharides with galactose and N-acetylglucosamine residues attached to a common core, alpha Man2 beta Man beta GlcNAc(+/- alpha-L-Fuc)beta GlcNAc. About 50% of the oligosaccharides contain one or two outer chains composed of one beta-linked N-acetylglucosamine and two beta-linked galactose residues attached to the core portions, and the others seem to be metabolic intermediates. Based on the results of studies on the binding of alpha-mannosidase to RCA (Ricinus communis agglutinin) I-agarose and MBP (mannan-binding protein)-Sepharose, which are specific for glycoproteins possessing N-acetyllactosamine-type and oligomannoside-type (including oligomannosides with N-acetylglucosamine at the reducing termini) oligosaccharides, respectively, about 85% of the enzyme molecules were found to have both types of oligosaccharides. Similarly, it was shown that of the several acid hydrolases present in the lysosomes purified from rat liver, only alpha-mannosidase has both types of oligosaccharides, and the greater parts of beta-glucuronidase, acid phosphatase and beta-N-acetylhexosaminidase seem to have only oligomannoside-type oligosaccharides.