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The paper describes the synthesis of an aminopropyl glycoside of hexasaccharide structurally related to the branched fragment of Candida utilis glucomannan, consisting of tetra-α-(1→2)-d-mannoside, the non-reducing end of which is glycosylated with α-glucopyranose and α-mannopyranose residues attached through the (1→2) and (1→3) linkages, respectively. The target structure was assembled by block synthesis with controlled α-stereoselectivity of formation of each glycosidic bond. The resulting hexasaccharide was further converted to a biotinylated conjugate, which, together with previously synthesized similar oligosaccharides, will be used to study the antigenic properties of mannans of Candida fungi. [ABSTRACT FROM AUTHOR]

Naturally circulating antibodies could dramatically change the activity of immunogens. In some cases, cross-interference between antibodies led to the loss of their opsonizing ability. Therefore, the study of antibody repertoire in blood sera of healthy donors is helpful for the development of vaccines and diagnostic kits. Levels of antibodies to fragments of biologically significant glucosamine and galactosamine polysaccharides and their N-acetylated derivatives were first studied in blood sera of 34 healthy donors using six biotinylated carbohydrate ligands. The highest titer of antibodies was found to poly-β-(1→6)-N-acetylglucosamine (PNAG), including its fully de-N-acetylated fragment. High antibody titers to the galactosaminoglycan (GG) fragments were also detected. For both PNAG and GG, the level of antibodies to N-acetylated ligands was higher than to the ligands with free amino groups. A correlation between the antibody titers for the respective N-acetylated and N-deacetylated forms was observed, which may suggest a cross interaction. No significant amounts of the antibodies to the chitooligosaccharides were detected. The results obtained will help to rationally plan further immunological studies aimed at the development of new vaccines and diagnostic kits. [ABSTRACT FROM AUTHOR]

Substituted β-glucosides of gallic acid and resorcinol, occurring naturally in trace amounts, as well as their O-gallates, which are of interest as covalent blockers of the main protease of the SARS-CoV-2 virus, were synthesized. [ABSTRACT FROM AUTHOR]

3-Aminopropyl-4,6-dideoxy-4-formamido-α-d-mannopyranosyl-(1→3)-4,6-dideoxy-4-formamido-α-d-mannopyranoside, a disaccharide structurally related to the M antigenic fragment of Brucella O-polysaccharides, was synthesized starting from 1,2,3-tri-O-acetyl-4-azido-4,6-dideoxy- and 1,3-di-O-acetyl-4-azido-2-O-benzyl-4,6-dideoxy-α-d-mannopyranoses. [ABSTRACT FROM AUTHOR]

Fucosylated chondroitin sulfate FCS-Hf and preparations of fucan sulfates Hf-Fuc1 and Hf-Fuc2 were isolated from the Vietnamese sea cucumber Holothuria (Stauropora) fuscocinerea. Separation of the polysaccharides was carried out using anion-exchange chromatography on DEAE-Sephacel. The structure of polysaccharides was established by determinations of the content of monosaccharides and sulfate, as well as by NMR spectra. It was shown that FCS-Hf was built of the repeating trisaccharide fragments, with alternating 3-linked N-acetyl-β-D-galactosamine and 4-linked β-D-glucuronic acid residues forming the main polymer chain, which carries α-L-fucose residues as side branches attached to O3 of glucuronic acid. The regular structure of the polymer is masked by an uneven distribution of sulfate groups attached to fucose residues (2,4-disulfate, 3,4-disulfate and 4-monosulfate in a ratio of 2 : 2 : 1) and galactosamine residues (4,6-disulfate and 4-monosulfate in a ratio of 3 : 1). It was also shown that fucan sulfate Hf-Fuc1 contained predominantly linear molecules built of 4-linked α-L-fucose 3-sulfate residues, while Hf-Fuc2 appeared to be a mixture of several related linear and branched fucan sulfates containing 3-linked and 4-linked α-L-Fuc residues sulfated at different positions. [ABSTRACT FROM AUTHOR]

In the course of synthesis of oligosaccharides related to fragments of the capsular polysaccharide of Haemophilus influenzae type e, reactions of 2-O-trifluoromethanesulfonate β-D-glucopyranoside derivatives with the azide anion were studied. The reactions gave products of both nucleophilic substitution and rearrangement accompanied by 6-membered pyranose ring contraction to a 5-membered ring through (O5–C2)-cyclization. The formation of these products was interpreted for the first time using quantum mechanical calculations. [ABSTRACT FROM AUTHOR]

Glycosylation of primary (3-trifluoroacetamidopropanol) and secondary (methyl 2,3-O-isopropylidene-α-l-rhamnopyranoside) alcohols with phenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-1-seleno-α-d-glucopyranoside in the presence of N-iodosuccinimide and trimethylsilyl triflate in diethyl ether afforded the corresponding 2-azido-2-deoxyglu-cosides in rather high yields and with good α-stereoselectivity (α:β = 3−5:1). Similar glycosylation with phenyl 3,4,6-tri-O-acetyl-2-azido-2-deoxy-1-seleno-α-d-manno-pyranoside resulted exclusively in α-linked 2-azido-2-deoxymannosides. [ABSTRACT FROM AUTHOR]

Fungal mannans are polysaccharide antigens located on the cell wall surface of various representatives of the fungal kingdom. Titers of the IgG antibodies to Candida albicans mannan are determined in the diagnosis of the candidiasis infection. Owing to high complexity and heterogeneity of the structure of natural mannans, the determination of the exact epitope structure recognized by antibodies is extremely important for the improvement of diagnostic tools based on the detection of anti-mannan antibodies. A high level of the antibodies to mannan was also found in healthy donors. However, it remains undetermined what structural epitope was recognized in this case. The levels of the IgG and IgM antibodies against individual structural fragments of mannan in the blood sera of healthy donors were determined. The anti-mannan antibody response was measured using enzyme immunoassay in a random sample of 31 blood sera of healthy donors on a panel of 11 synthetic mannooligosaccharides of various structures. A high antibody titer was found for the antigens containing the β-mannosidic bond, and the highest values were achieved in the case of two (1→2)-linked β-mannose residues. No significant level of the antibodies was revealed for antigens containing only α-mannose residues. Thus, it can be concluded that β-mannans appear to be much stronger antigens. It is assumed that the detection of antibodies to β-mannans in the sera of healthy donors can be a source of false positive results in the serological diagnosis of the Candida infection. [ABSTRACT FROM AUTHOR]

Symptoms of the new coronavirus infection that appeared in 2019 (COVID-19) range from low fever and fatigue to acute pneumonia and multiple organ failure. The clinical picture of COVID-19 is heterogeneous and involves most physiological systems; therefore, drugs with a wide spectrum of mechanism of action are required. The choice of the treatment strategy for post-COVID-19 syndrome is still a challenge to be resolved. Polysaccharides with a high fucose content derived from seaweed and marine animals can form the basis for the subsequent development of promising agents for the treatment of COVID-19 and post-COVID-19 syndrome. This class of biopolymers is characterized by a variety of biological activities, including antiviral, antithrombotic, anticoagulant, hemo-stimulating, anti-inflammatory and immune-regulatory. Low molecular weight derivatives of these polysaccharides, as well as synthetic oligosaccharides with a sufficient amount and sulfation type may be considered as the most promising compounds due to their better bioavailability, which undoubtedly increases their therapeutic potential. [ABSTRACT FROM AUTHOR]

In order to find efficient anticancer agents among natural sulfated polysaccharides and their analogs, we studied the anti-angiogenic capacity of natural fucoidans from brown algae Saccharina latissima (SL) and Chordaria flagelliformis (CF) along with chemically modified fucoidan from Punctaria plantaginea (MF) and synthetic completely sulfated fucooctasaccharide (OS) built of (1→3)-bonded residues of α-l-fucopyranose of exhibiting anti-angiogenic activity in vitro on the model of formation of capillary-like structures (precapillaries) by endothelial cells or their precursors, mesenchymal stem cells. The activity of the studied compounds was tested on cells of low-grade human breast cancer of the MDA-MB-231 line and multipotent mesenchymal stem cells (MSCs) of dogs. Fucoidan CF and its derivatives SL and MF in a concentration of 0.1 mg mL−1 reliably suppress the formation of closed circular structures by cancer cells. The formation of capillary-like structures of MSC is inhibited by fucoidan CF in concentrations of 0.1 and 0.01 mg mL−1. Modified fucoidan MF and synthetic oligosaccharide OS are somewhat less active, which can be due to their insufficiently high molecular weights and specific features of the sulfation character. The obtained data indicate that the search for anti-angiogenic agents in the series of sulfated oligosaccharides with the variation of the molecular size, structure, and sulfation pattern should be extended. [ABSTRACT FROM AUTHOR]

An extract from the knotwood of Populus tremula (quaking aspen) was studied by HPLC, NMR spectroscopy, and mass spectrometry in order to identify new sources of natural compounds as promising basis for the development of medicinal agents. The following compounds were detected and characterized in the extract: 6-O-(α-l-rhamnopyranosyl)-β-d-glucopyranosyl E-3-(4-hydroxyphenyl)acrylate, 6-O-(α-l-rhamnopyranosyl)-β-d-glucopyranosyl Z-3-(4-hydroxyphenyl)acrylate, trans-3-(4-hydroxyphenyl)acrylic acid, 7-O-(β-d-glucopyranosyl)naringenin, dihydrokaempferol, and naringenin. [ABSTRACT FROM AUTHOR]

Hyaluronic acid (HA) is a natural polysaccharide constructed from the alternating residues of β-D-glucuronic acid and N-acetyl-β-D-glucosamine. Being a component of glycoproteins and proteoglycans, HA performs important functions in living organisms. For example, HA plays a key role in the development of cell division and migration, vascular formation, inflammation, and oncogenesis. The review summarizes the successfully accomplished syntheses of oligosaccharides related to HA chains, an analysis of strategies for assembling the corresponding carbohydrate chains, and the evaluation of types of the used glycosyl-donors and glycosyl-acceptors, as well as strategies for choosing protective groups in the synthetic blocks. The use of enzymatic splitting of natural samples of HA and chondroitin sulfate in the work to produce appropriate low-molecular-weight oligosaccharides is also considered. Synthesized oligosaccharides and glycoconjugates based on them are valuable models for establishing a relationship between the structure and biological properties of HA and for developing approaches to the production of therapeutic drugs based on HA, including those for wound healing and treatment of inflammatory processes, as well as inhibitors of certain stages of oncogenesis. [ABSTRACT FROM AUTHOR]

The polysaccharide mannan is the main surface antigen of the cell wall of Candida fungi, playing an important role in the pathogenesis of diseases caused by these mycopathogens. Mannan has a complex, comb-like structure and includes a variety of structural units, with their combination varying depending on the Candida species and strain. Glucomannan, a polysaccharide from Candida utilis, contains terminal α-d-glucose residues attached to oligomannoside side chains. This paper describes the first synthesis of a pentasaccharide structurally related to C. utilis glucomannan fragment, which is an α-(1→2)-linked tetramannoside terminated at the non-reducing end by an α-d-glucopyranosyl residue. The pentasaccharide was obtained as a 3-aminopropyl glycoside, which made it possible to synthesize also its biotinylated derivative, suitable for various glycobiological studies. The most complicated step in the pentasaccharide synthesis was stereoselective 1,2-cis-glycosylation to attach the α-d-glucopyranosyl residue. This was accomplished using a glucosyl donor specially developed in our laboratory, the protecting groups of which provide the necessary α-stereoselectivity. The target biotinylated pentasaccharide thus obtained will be used in the future as a model antigen for the detection of immunodeterminant epitopes of Candida mannans. [ABSTRACT FROM AUTHOR]

An extract from the knotwood of Abies sibirica (Siberian fir) was studied by HPLC, NMR spectroscopy, and mass spectrometry with the goal to identify new sources of phytoestrogens, which are promising medicinal agents, and to obtain new representatives of natural compounds of the indicated group. The following compounds were found in the extract and identified: 2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-4-[1-hydroxy-1-(4-hydroxy-3-methoxy-phenyl)methyl]tetrahydrofuran (1), 5′-(7-hydroxymatairesinyl)-5″-(7‴-hydroxymatairesinol) (2), 2,3-bis(4-hydroxy-3-methoxybenzyl)butane-1,4-diol (3, (−)-secoisolariciresinol), and 3-(4-hydroxy-3-methoxybenzyl)-5-(4-hydroxy-3-methoxyphenyl)-4-(hydroxymethyl)dihydro-furan-2(3H)-one (4). Compound 2 was previously unknown. [ABSTRACT FROM AUTHOR]

β-(1→3)-d-Glucan is a branched polysaccharide present in the inner layer of the cell wall of various representatives of the fungal kingdom. Therefore, this polysaccharide is considered as a common marker for the laboratory diagnosis of mycoses of various etiologies. However, low concentration of β-(1→3)-d-glucan in biological fluids (∼40 pg mL−1) requires the development of highly sensitive methods for its determination. One of the most convenient types of bioassays is based on immunochemical approaches, in which the most important stage is selection and characterization of monoclonal antibodies (mAb). In this communication, the binding constant of mAb 3G11 and the synthetic oligosaccharide β-d-Glcp-[(1→3)-Glcp]8, which is related to the linear moiety of fungal glucan, was determined in solution for the first time using fluorescence polarization immunoassay (FPIA) method. The obtained information will be used subsequently for the development of analytical systems for FPIA detection of β-(1→3)-d-glucan. [ABSTRACT FROM AUTHOR]

This review summarizes the experience in laboratory- and industrial-scale syntheses of glycoconjugate vaccines used for prevention of infectious diseases caused by Haemophilus influenzae type b bacteria based on the linear capsular polysaccharide poly-3-β-D-ribosyl-(1→1)-D-ribitol-5-phosphate (PRP) or related synthetic oligosaccharide ligands. The methods for preparation of related oligosaccharide derivatives and results of the studies evaluating effect of their length on immunogenic properties of the conjugates with protein carriers are overviewed. [ABSTRACT FROM AUTHOR]

Two stilbenoids previously not observed in Shorea robusta (Sal) were isolated from 30% aqueous isopropanol extract of its knotwood. The compounds were purified by HPLC and identified as ampelopsin A and vatalbinoside A by NMR spectroscopy and mass-spectrometry. [ABSTRACT FROM AUTHOR]

6-O-Acetylated derivatives of D-hexopyranosides are valuable intermediates in synthetic carbohydrate chemistry. We have developed a new simple procedure for selective acetylation of the primary hydroxyl group in methyl D-hexopyranosides consisting in treatment with a mixture of acetic anhydride and acetic acid at 50°C. As a result, corresponding 6-acetates were formed in 40–50% yield. [ABSTRACT FROM AUTHOR]

Synthetic oligosaccharides are objects of interest as model compounds in studies on the biological activity of natural compounds, but also as components for new drugs, glycoconjugate vaccines, carbohydrate diagnostic agents and various other products. The key stage in oligosaccharide synthesis is the glycosylation reaction, which leads to the formation of a linkage between carbohydrate fragments. This review highlights a current problem in modern glycochemistry – the methods of stereocontrol in the glycosylation reaction. Protecting groups within the structure of glycosyl donors are considered as stereocontrolling factors, affecting the reaction mechanism by means of (1) participation or anchimeric assistance, (2) deactivation, (3) intramolecular aglycone delivery. The well-established mechanism of neighboring group participation at O-2 for the synthesis of 1,2- trans glycosides is shown, as well as its modern modifications, including activating ethers, chiral protecting groups and achiral bicyclic glycosyl donors. The mechanisms of remote participation from O-3, O-4 and O-6 of the glycosyl donor are discussed in detail. In addition, approaches to stereocontrol using deactivating protection (conformation constraining and electron withdrawing groups) are described. Finally, synthetic approaches based on intramolecular aglycone delivery are considered. Both classical and novel protecting groups used to control the steric outcome of glycosylation are presented, the mechanisms underlying the presented approaches are discussed in detail, while also showing how the described strategies apply to the synthesis of complex structures. [ABSTRACT FROM AUTHOR]

Streptococcus pneumoniae is a Gram-positive bacterium (pneumococcus) that causes severe diseases in adults and children. It was established that some capsular polysaccharides of the clinically significant serotypes of S. pneumoniae in the composition of commercial pneumococcal polysaccharide or conjugate vaccines exhibit low immunogenicity. The review considers production methods and structural features of the synthetic oligosaccharides from the problematic pneumococcal serotypes that are characterized with low immunogenicity due to destruction or detrimental modification occurring in the process of their preparation and purification. Bacterial serotypes that cause severe pneumococcal diseases as well as serotypes not included in the composition of the pneumococcal conjugate vaccines are also discussed. It is demonstrated that the synthetic oligosaccharides corresponding to protective glycotopes of the capsular polysaccharides of various pneumococcal serotypes are capable of inducing formation of the protective opsonizing antibodies and immunological memory. Optimal constructs of oligosaccharides from the epidemiologically significant pneumococcal serotypes are presented that can be used for designing synthetic pneumococcal vaccines, as well as test systems for diagnosis of S. pneumoniae infections and monitoring of vaccination efficiency. [ABSTRACT FROM AUTHOR]

According to HPLC, NMR spectroscopy, and mass spectrometry, the extracts of the knotwood of Salix capreal. contain catechin (1), 7-O-(β-d-glucopyranosyl)dihydrokaempferol (2), 7-O-(β-d-glucopyranosyl)dihydrokaempferol-4′-O-methyl ether (3), 7-O-(β-d-glucopyranosyl)naringenin (prunin) (4), naringenin (5), and dihydrokaempferide (6). Compound 3 was not described previously. [ABSTRACT FROM AUTHOR]

Electrospray ionization (ESI) high resolution mass spectra of positively charged ions (the first and the second order) of protonated molecules of isomeric β-(1→6)-linked cyclic tetrasaccharides of the Glcp2GlcpN2 composition were recorded and interpret. It was shown that the second-order mass spectra of these compounds have some differences reflecting the mutual positions of the glucopyranose and glucosamine residues. The most significant qualitative differences were observed for MS/MS spectra of doubly protonated, doubly charged molecules. [ABSTRACT FROM AUTHOR]

Galactomannan (GM) is a specific polysaccharide antigen of opportunistic mold fungi of the genus Aspergillus. The detection of GM in patients' biological fluids is a reliable criterion for the diagnosis of invasive pulmonary aspergillosis, a severe disease. In this report, we evaluated the analytical capabilities of the fluorescence polarization immunoassay (FPIA) for detection of GM. Using FPIA, the high affinity of the monoclonal antibody 7B8 to the synthetic oligosaccharide β-d-Galf-[(1→5)-β-d-Galf]3-(1→6)-α-d-Manp related to the galactomannan fragment was shown. The binding constant in this interaction was found to be equal to (1.02±0.01) • 108 L mol-1. The detection limit determined for this oligosaccharide with the competitive FPIA method is 3 ng mL-1. The data obtained indicate the possibility of using FPIA for the diagnosis of invasive aspergillosis. [ABSTRACT FROM AUTHOR]

Chemical composition of the extract from the Pinus roxburghii Sarg. knotwood was studied for the first time. The extracts were obtained by ultrasound assisted sequential extraction of knotwood with hexane, acetone—water (95 : 5, v/v), and water. According to GC-MS analysis, hexane extract was dominated by monoterpenoids amounting to 53.57% and sesquiterpenoids (41.05%). Components of the acetone—water (95 : 5, v/v) extract were isolated, purified by HPLC, and identified by NMR spectroscopy and mass spectrometry as 2,3-bis(4-hydroxy-3-methoxybenzyl)butan-1,4-diol, 3-hydroxy-3,4-bis(4-hydroxy-3-methoxybenzyl)dihydrofuran-2(3H)-one and 3,4-bis(4-hydroxy-3-methoxybenzyl)dihydrofuran-2(3H)-one. These compounds demonstrated notable antioxidant capacity determined using the amperometric method. [ABSTRACT FROM AUTHOR]

The composition of the extract from the Dalbergia Sissoo Linn. knot wood was studied. Components obtained by extraction with 95% aqueous acetone were isolated, purified by HPLC, and identified by NMR spectroscopy and mass spectrometry as 7,6,3',5'-trihydroxyflavanone (1), 7,3',4'-trihydroxy-6-methoxyflavanone (2), 7,3',5'-trihydroxyflavanone (3), 6-hydroxy-7-methoxy-4-phenyl-2H-chromen-2-one (dalbergin) (4), 2-methoxy-5-(1-phenylallyl)cyclohexa-2,5-diene-1,4-dione (dalbegione) (5), and 2,4-dimethoxy-5-(1-phenylallyl)phenol (dalbergiphenol) (6). In the extract from the Dalbergia Sissoo Linn. wood knots, compounds 1–3 were found for the first time. The isolated compounds demonstrated notable antioxidant ability determined by using the amperometric method. [ABSTRACT FROM AUTHOR]

We studied carbohydrate specificity and isotypes of antibodies to BSA-conjugated tetrasaccharide, a repeating unit of the capsular polysaccharide of Streptococcus pneumoniae serotype 14, in mouse polyclonal sera and hybridoma-synthesized products. Natural IgM antibodies to the tetrasaccharide containing epitopes similar to surface carbohydrate structures of mammalian and human cells in low titers were determined in native mouse serum by ELISA using biotinylated tetrasaccharide and synthetic capsular polysaccharide as the solid-phase antigens. Polyclonal sera to the conjugated tetrasaccharide contained IgM and all subclasses of IgG antibodies, which were detected in a higher titer when the biotinylated tetrasaccharide was used as a solid phase antigen compared to synthetic capsular polysaccharide. Monoclonal antibodies to S. pneumoniae serotype 14 tetrasaccharide were identified in an equivalent titer using either biotinylated tetrasaccharide or synthetic capsular polysaccharide. Monoclonal antibodies obtained in vitro belonged to IgM isotype and cross-reacted with secondary full-size IgG antibodies. In the serum of mice inoculated with hybridoma, IgM and IgG2a antibodies recognizing the tetrasaccharide epitope in the structure of synthetic capsular polysaccharide were simultaneously determined. [ABSTRACT FROM AUTHOR]

Noncatalytic acetylation of methyl 2,3-di-O-benzoyl-α-d-glucopyranoside with acetic acid or acetic anhydride proceeds regioselectively at the primary hydroxyl group and affords methyl 6-O-acetyl-2,3-di-O-benzoyl-α-d-glucopyranoside in good yield. The possibility of 6-O-acetylation should be taken into account when removing a 4,6-O-benzylidene protecting group with aqueous acetic acid at elevated temperature. [ABSTRACT FROM AUTHOR]

Abstract: Laboratory animals (the California rabbit) were immunized with natural preparations of Saccharomyces cerevisiae and Candida krusei yeasts. The resulting sera have been analyzed with ligand libraries constructed from synthetic oligosaccharides related to the main carbohydrate components of the fungal cell wall. It is shown that the antibodies in the studied sera predominantly recognize mannan fragments, with the carbohydrate specificity profile being different for S. cerevisiae and C. krusei. Sera against S. cerevisiae contained antibodies that recognize β-glucan, and the minimal recognizable epitope is linear trisaccharide. These results are necessary for the creation of needed immunoenzyme diagnostics for the detection and species characterization of fungi. [ABSTRACT FROM AUTHOR]

Brush rabbits were immunized with injections prepared from the fungi Aspergillus fumigatus, Aspergillus niger, and Aspergillus repens. A library of synthetic biotinylated oligosaccharides containing the key fragments of antigenic polysaccharides of the fungal cell wall—galctomannan, α- and β-glucans, mannan, and chitin—was used to analyze carbohydrate specificity. The anticarbohydrate antibodies obtained from animals immunized with preparations from A. fumigatus and A. repens predominantly recognized epitopes containing galactofuranoside residues, while the majority of the antibodies against A. niger bound the chitooligosaccharide ligand. These results are the basis for the identification of specific markers required for the development of immunoenzyme test systems. [ABSTRACT FROM AUTHOR]

The carbohydrate specificity of antibodies obtained by immunizing laboratory animals with immunogens prepared from the Aspergillus fumigatus cell wall was analyzed using the library of biotinylated synthetic oligosaccharides. It has been shown that the main part of antipolysaccharide antibodies recognizes galactomannan in the studied immunogens with preference to its fragments containing more than two β-(1→5)-linked galactofuranosyl units. The data obtained can form the basis for the development of enzyme immunoassay for the detection of this dangerous fungal pathogen. [ABSTRACT FROM AUTHOR]

Positive and negative ion high-resolution electrospray ionization mass spectra (MS and MS2) of cyclooligo-β-(1→6)-D-glucosamines and cyclooligo-β-(1→6)-N-acetyl-D-glucosamines were acquired and interpret. It was shown that the cleavages of glycosidic bonds are the main processes in the decay of protonated and metallated molecules. In addition, elimination of the water molecules (and ammonia for cyclooligo-β-(1→6)-D-glucosamines) was observed along with other processes including the unknown skeletal rearrangement. A primary fragmentation of the negatively charged ions (deprotonated molecules) differed from that of the positively charged ones. [ABSTRACT FROM AUTHOR]

The electrospray ionization high-resolution mass spectra of biotinylated hexaethylene glycol-spacered molecular probes bearing biologically relevant carbohydrate moieties in positive and negative modes were recorded and interpreted. Collisionally induced decay mass spectra (positive mode) revealed different patterns depending on the charge of the parent ion, attached cations (or ions), the composition, and the sequence of carbohydrate fragments. The most intense peaks (two series) originated from the sequential cleavage of glycoside bonds resulting in charge location on the reducing end (Y series observed for all of the test compounds) or nonreducing end (B series). Hexaethylene glycol chain fragmentation giving rise to the cleavage of the C-O bond remote from the biotin moiety was observed. Other fragment ions lighter than the above by a difference of (C2H4O)n were absent or much smaller. Similar fragmentation was found for all of the nonsulfated biotinylated glycosides with the hexaethylene glycol spacer thus demonstrating that this type of fragmentation was characteristic of such molecular probes. Similar cleavages along with biotin moiety decay via the elimination of H2S and H2CS were observed for negative ions in the collisionally induced decay mass spectra of sulfated and neutral molecular probes. [ABSTRACT FROM AUTHOR]

An Erratum to this paper has been published: https://doi.org/10.1134/S1068162022340015 [ABSTRACT FROM AUTHOR]

Persulfated derivatives of natural polyhydroxy compounds, such as lignans secoisolariciresinol, and isolariciresinol, flavonoid dihydroquercetin, and myo-inositol, have been synthesized. The ability of these compounds to inhibit the intrinsic pathway of blood coagulation (APTT-test) and to reduce the activity of coagulation factor Xa in the presence of antithrombin(III) has been studied. [ABSTRACT FROM AUTHOR]

A fucoidanase preparation from the marine mollusk Littorina kurila cleaved some glycosidic bonds in fucoidan from the brown alga Fucus distichus, but neither fucose nor lower oligosaccharides were produced. The main product isolated from the incubation mixture was a polysaccharide built up of disaccharide repeating units →3)-α-L-Fuc p-(2,4-di-SO)-(1→4)-α-L-Fuc p-(2SO)-(1→, the structure coinciding with the idealized formula proposed for the initial substance. A polymer fraction with the same carbohydrate chain but sulfated only at positions 2 and nonstoichiometrically acetylated at positions 3 and 4 of fucose residues was isolated as a minor component. It is suggested that the native polysaccharide should contain small amounts of non-sulfated and non-acetylated fucose residues, and only their glycosidic bonds are cleaved by the enzyme. The enzymatic hydrolysis showed that irregular regions of the native polysaccharide containing acetylated and partially sulfated repeating units were assembled in blocks. [ABSTRACT FROM AUTHOR]