Grigorij Kogan - Academia.edu (original) (raw)
Papers by Grigorij Kogan
Comptes Rendus De L Academie Bulgare Des Sciences, 2000
Journal of Biological Chemistry, Apr 1, 1996
PubMed, Nov 1, 1990
Yeast cell wall contains mainly polysaccharides. Among them beta-1,3-D-glucans play role of the s... more Yeast cell wall contains mainly polysaccharides. Among them beta-1,3-D-glucans play role of the skeletal carcass of the yeast cell wall, while D-mannans represent its surface antigens. Mannans are built of alpha-1,6-linked polymannosyl backbone with the side chains consisting of alpha-1,2- and alpha-1,3-linked mannosyl units. The branching degree and length of the side chains are specific for individual yeast strains. By means of subsequent alkaline and acid extractions mannans and soluble glucans can be separated, leaving insoluble particulate glucan. The latter is inhomogenous and consists of microfibrillar and amorphous components. By means of gamma-irradiation these two components were separated and the structure of each was determined. It was found that microfibrillar glucan had a structure close to that of immunomodulating glucans isolated from Japanese fungi. By means of carboxymethylation of particulate glucan its water-soluble derivatives were prepared. Some immunopharmacological properties of the particulate glucan and its soluble derivatives are discussed in relation to their structural and physico-chemical characteristics.
Сибирский научный медицинский журнал, 2007
Сибирский научный медицинский журнал, 2006
Folia Microbiologica, Jun 1, 1993
Elsevier eBooks, 2019
Abstract Chronic respiratory diseases (CRDs) are diseases of the airways and other structures of ... more Abstract Chronic respiratory diseases (CRDs) are diseases of the airways and other structures of the lung. Some of the most common are asthma, chronic obstructive pulmonary disease, occupational lung diseases, and pulmonary hypertension. CRDs affect hundreds of millions people and cause an immense health burden as leading cause of disability and mortality. Tackling respiratory diseases also poses enormous economic burden on national health care systems. Therefore, finding solutions to deal with the growing incidence of respiratory diseases requires a global approach integrating international efforts in health research and disease management in the area of respiratory diseases. Through its Framework Programmes for Research and Innovation, the European Union (EU) funds frontier research, basic and clinical research and innovative product development, and training and mobility of researchers. Collaborative, multidisciplinary research is not limited to EU member states, and in providing its support, the EU is involved in a strategic cooperation with other public and private funders worldwide. Over the past 10 years, the EU invested over € 538 million into research on respiratory diseases that helped broaden knowledge in this area and led to the development of novel therapies and medical devices. This chapter presents a brief overview of the results of support of the EU in the area of respiratory diseases.
Journal of Magnetic Resonance, Series B, Jul 1, 1994
Ultrasonics Sonochemistry, Mar 1, 1999
By means of ultrasonication two fractions of the carboxymethylated chitin-glucan complex isolated... more By means of ultrasonication two fractions of the carboxymethylated chitin-glucan complex isolated from the cell walls of 13 the filamentous fungus Aspergillus niger were obtained. Elemental analysis as well as C NMR investigation of the high-molecular weight (M 680 kDa) and low-molecular weight (M 75 kDa) fractions revealed their essentially different w w chitin content. HPLC analysis of the fractions produced by ultrasonic treatment of different duration, combined with nitrogen assay showed steadily increasing chitin content in the faster eluted fraction that allows one to suggest the different susceptibility of the two components of the chitin-glucan complex to the ultrasonication.
Journal of Medicinal Food, Jun 1, 2002
Antioxidative capabilities of carboxymethylated (1 R 3)-b-D-glucan from Saccharomyces cerevisiae ... more Antioxidative capabilities of carboxymethylated (1 R 3)-b-D-glucan from Saccharomyces cerevisiae cell wall, a-tocopherol, and mannitol against lipid peroxidation in phosphatidylcholine liposomes induced by OH. radicals produced with Fenton's reagent (H 2 O 2 /Fe 21) were studied using absorption ultraviolet-visible spectrophotometry. It was found that (1 R 3)-b-Dglucan is an antioxidant with the scavenging ability lying between that of a-tocopherol, which is known to be incorporated in the lipid bilayer, and the water-soluble antioxidant, mannitol.
Studies in natural products chemistry, 2000
Abstract Glucans, or polymers of D-glucose linked by (1→3)-β and (1→6)-β glycosidic linkages are ... more Abstract Glucans, or polymers of D-glucose linked by (1→3)-β and (1→6)-β glycosidic linkages are the common polysaccharides of the fungal cell wall. They are usually located in the inner part of the wall and play the role of skeletal polysaccharide contributing to the shape and rigidity of the cell wall. The β-glucan molecules are interlinked by the hydrogen bonds and sometimes occur in a complex with other polysaccharides, such as chitin. β-Glucans isolated from the various yeast and fungal species may have different molecular weight or other structural parameters such as degree of branching or the length of the side-chains which may affect their solubility in water. Many fungal β-glucans possess remarkable ability to enhance the immune system, i.e. act as immunomodulators. Numerous studies have demonstrated the activity of β-glucans as biological response modifiers that are able to exert beneficial effect in host by demonstrating antitumor, antibacterial, antiviral and antiparasitic activities. Some studies have attempted to correlate biological activity of individual β-glucans to their spatial structure or helical conformation. However neither such correlation nor the precise mechanism of the activation of the immune system by β-glucans have been unambiguously proven. The present article reviews the existing knowledge on the immunological activity of the fungal β-glucans and provides some recent results on the radioprotective and antimutagenic activity of the β-glucan isolated from the baker's yeast.
Water vapour sorption by vinyl caprolactam polymer samples with the molar masses in the range of ... more Water vapour sorption by vinyl caprolactam polymer samples with the molar masses in the range of 2.6—25 × 103 g mol−1 was investigated. Influence of the degree of polymerization on sorption was discovered for the oligomers. This dependence was not observed for the high-molar-mass polymers. The possible causes of this phenomenon are discussed.
Free-radical polymerization of N-vinylcaprolactam (VCL) in the presence of chain-transfer agents ... more Free-radical polymerization of N-vinylcaprolactam (VCL) in the presence of chain-transfer agents has been studied to obtain polyvinylcaprolactam possessing a predetermined relative molecular mass. Allyl compounds have been used as chain-transfer agents. Free-radical polymerization kinetics of VCL in the presence of allylbenzene and allylcaprolactam has been investigated as well as free-radical polymerization of VCL in isopropyl alcohol solution. The effect of reaction mixture composition on the rate and degree of polymerization has been studied, too. Possibility of synthesis of vinylcaprolactam oligomers with terminal hydroxyl groups has been demonstrated. Influence of a series of substituents at allylic compounds on kinetics of chain transfer has been investigated using quantum-chemical methods.
Russian Journal of Bioorganic Chemistry, Feb 1, 2007
3-Aminopropyl glycosides of α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-Dmannopyranosyl-(... more 3-Aminopropyl glycosides of α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-Dmannopyranosyl-(1 2)-α-D-mannopyranose, α-D-mannopyranosyl-(1 3)-α-D-mannopyranosyl-(1 2)α-D-mannopyranosyl-(1 2)-α-D-mannopyranose, and α-D-mannopyranosyl-(1 2)-[ α-D-mannopyranosyl-(1 3)]-α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-D-mannopyranose were efficiently synthesized starting from ethyl 2-O-acetyl(benzoyl)-3,4,6-triO -benzyl-1-thio-α-D-mannopyranoside, ethyl 4,6-di-O-benzyl-2-O-benzoyl-1-thio-α-D-mannopyranoside, ethyl 4,6-di-O-benzyl-2,3-di-O-benzoyl-1-thio-α-D-mannopyranoside, and 2,3,4,6-tetra-O-benzoyl-α-D-mannopyranosyl bromide. The oligosaccharide chains synthesized correspond to the three structural types of side chains of mannan from Candida albicans cell wall. A conjugate of the third pentasaccharide with bovine serum albumin was prepared using the squarate method.
Experimental oncology, 2006
One of the advanced methodologies of the tumor therapy is the application of the so-called biolog... more One of the advanced methodologies of the tumor therapy is the application of the so-called biological response modifiers used for activation of the endogenous antitumor mechanisms and combined with classical cytotoxic agents. The aim of this work was the investigation of the effect of sulfoethylated (1-->3)-beta-D-glucan (SEG) in the treatment of experimental murine leukoses in combination with cyclophosphamide (CPA) and its ability to modulate the activity of lysosomal enzymes in tumor tissues. The solid forms of inoculated murine leukoses P388 and L1210/1 were transplantated to male DBA/2 mice. The therapy was performed by treating animals with CPA (Biokhimik, Saransk, Russia) alone or in combination with SEG (Institute of Chemistry, Slovak Academy of Sciences, Slovakia). CPA was administered in saline as a single intraperitoneal (ip) injection on the 10th day after tumor transplantation; SEG was administered to mice ip 3 days after tumor transplantation with the intervals in 3...
Carbohydrate Polymers, 1990
Cell wall o-mannans were isolated from all eight known pathogenic strains of genus Candida. Their... more Cell wall o-mannans were isolated from all eight known pathogenic strains of genus Candida. Their structural characterization was carried out by means of acetolysis and methylation analysis, as well as NMR spectroscopy. The results point out some common features and peculiarities of the structures of individual o-mannans. Differences observed in the structures of investigated mannans may be responsible for the differences in immunological properties of the corresponding yeast strains.
Plant Protection Science, 2017
Most of the experiments carried out in the area of plant protection have used chitin and chitosan... more Most of the experiments carried out in the area of plant protection have used chitin and chitosan obtained from the crustacean chitin which production is rather expensive. In our study we have applied the chitin-glucan complex prepared from the waste mycelia of filamentous fungi, from baker’s yeast. Five different polysaccharides have been used for the preparation of water-soluble compounds and the assay of their antifungal activity against plant pathogen Fusarium oxysporum. In the field experiments, application of the polysaccharides led to the diminished infestation as well as to significantly increased productivity of fresh weight of the plants (tomato). The results demonstrated that application of the polysaccharides led to increased production of cell wall and some outher and intermembrane-bound proteins. Although the nature of the observed proteins has not been yet established, it can be speculated that they represent some enzymes involved in the antiinfective defense mechanis...
Journal of Applied Polymer Science, 1995
Enzymatic and ultrasonic degradations of the carboxymethyl derivative of the p-1,3-Dglucan, isola... more Enzymatic and ultrasonic degradations of the carboxymethyl derivative of the p-1,3-Dglucan, isolated from the cell walls of baker's yeast Saccharomyces cerevisiae, are described. The samples obtained upon partial depolymerization of the two carboxymethylated glucans with the substitution degree of 0.56 and 0.91 were characterized by the distributions of their molecular weights and 13C-NMR spectra.
L'invention concerne un clathrate forme par association d'un derive d'acide hyaluroni... more L'invention concerne un clathrate forme par association d'un derive d'acide hyaluronique (a), d'un derive d'acide hyaluronique (b1) different de (a) capable de former un clathrate avec (a), et/ou d'un composant (b2) ne contenant pas de fraction d'acide hyaluronique mais pouvant former un clathrate avec (a); et son utilisation dans le domaine pharmaceutique.
Comptes Rendus De L Academie Bulgare Des Sciences, 2000
Journal of Biological Chemistry, Apr 1, 1996
PubMed, Nov 1, 1990
Yeast cell wall contains mainly polysaccharides. Among them beta-1,3-D-glucans play role of the s... more Yeast cell wall contains mainly polysaccharides. Among them beta-1,3-D-glucans play role of the skeletal carcass of the yeast cell wall, while D-mannans represent its surface antigens. Mannans are built of alpha-1,6-linked polymannosyl backbone with the side chains consisting of alpha-1,2- and alpha-1,3-linked mannosyl units. The branching degree and length of the side chains are specific for individual yeast strains. By means of subsequent alkaline and acid extractions mannans and soluble glucans can be separated, leaving insoluble particulate glucan. The latter is inhomogenous and consists of microfibrillar and amorphous components. By means of gamma-irradiation these two components were separated and the structure of each was determined. It was found that microfibrillar glucan had a structure close to that of immunomodulating glucans isolated from Japanese fungi. By means of carboxymethylation of particulate glucan its water-soluble derivatives were prepared. Some immunopharmacological properties of the particulate glucan and its soluble derivatives are discussed in relation to their structural and physico-chemical characteristics.
Сибирский научный медицинский журнал, 2007
Сибирский научный медицинский журнал, 2006
Folia Microbiologica, Jun 1, 1993
Elsevier eBooks, 2019
Abstract Chronic respiratory diseases (CRDs) are diseases of the airways and other structures of ... more Abstract Chronic respiratory diseases (CRDs) are diseases of the airways and other structures of the lung. Some of the most common are asthma, chronic obstructive pulmonary disease, occupational lung diseases, and pulmonary hypertension. CRDs affect hundreds of millions people and cause an immense health burden as leading cause of disability and mortality. Tackling respiratory diseases also poses enormous economic burden on national health care systems. Therefore, finding solutions to deal with the growing incidence of respiratory diseases requires a global approach integrating international efforts in health research and disease management in the area of respiratory diseases. Through its Framework Programmes for Research and Innovation, the European Union (EU) funds frontier research, basic and clinical research and innovative product development, and training and mobility of researchers. Collaborative, multidisciplinary research is not limited to EU member states, and in providing its support, the EU is involved in a strategic cooperation with other public and private funders worldwide. Over the past 10 years, the EU invested over € 538 million into research on respiratory diseases that helped broaden knowledge in this area and led to the development of novel therapies and medical devices. This chapter presents a brief overview of the results of support of the EU in the area of respiratory diseases.
Journal of Magnetic Resonance, Series B, Jul 1, 1994
Ultrasonics Sonochemistry, Mar 1, 1999
By means of ultrasonication two fractions of the carboxymethylated chitin-glucan complex isolated... more By means of ultrasonication two fractions of the carboxymethylated chitin-glucan complex isolated from the cell walls of 13 the filamentous fungus Aspergillus niger were obtained. Elemental analysis as well as C NMR investigation of the high-molecular weight (M 680 kDa) and low-molecular weight (M 75 kDa) fractions revealed their essentially different w w chitin content. HPLC analysis of the fractions produced by ultrasonic treatment of different duration, combined with nitrogen assay showed steadily increasing chitin content in the faster eluted fraction that allows one to suggest the different susceptibility of the two components of the chitin-glucan complex to the ultrasonication.
Journal of Medicinal Food, Jun 1, 2002
Antioxidative capabilities of carboxymethylated (1 R 3)-b-D-glucan from Saccharomyces cerevisiae ... more Antioxidative capabilities of carboxymethylated (1 R 3)-b-D-glucan from Saccharomyces cerevisiae cell wall, a-tocopherol, and mannitol against lipid peroxidation in phosphatidylcholine liposomes induced by OH. radicals produced with Fenton's reagent (H 2 O 2 /Fe 21) were studied using absorption ultraviolet-visible spectrophotometry. It was found that (1 R 3)-b-Dglucan is an antioxidant with the scavenging ability lying between that of a-tocopherol, which is known to be incorporated in the lipid bilayer, and the water-soluble antioxidant, mannitol.
Studies in natural products chemistry, 2000
Abstract Glucans, or polymers of D-glucose linked by (1→3)-β and (1→6)-β glycosidic linkages are ... more Abstract Glucans, or polymers of D-glucose linked by (1→3)-β and (1→6)-β glycosidic linkages are the common polysaccharides of the fungal cell wall. They are usually located in the inner part of the wall and play the role of skeletal polysaccharide contributing to the shape and rigidity of the cell wall. The β-glucan molecules are interlinked by the hydrogen bonds and sometimes occur in a complex with other polysaccharides, such as chitin. β-Glucans isolated from the various yeast and fungal species may have different molecular weight or other structural parameters such as degree of branching or the length of the side-chains which may affect their solubility in water. Many fungal β-glucans possess remarkable ability to enhance the immune system, i.e. act as immunomodulators. Numerous studies have demonstrated the activity of β-glucans as biological response modifiers that are able to exert beneficial effect in host by demonstrating antitumor, antibacterial, antiviral and antiparasitic activities. Some studies have attempted to correlate biological activity of individual β-glucans to their spatial structure or helical conformation. However neither such correlation nor the precise mechanism of the activation of the immune system by β-glucans have been unambiguously proven. The present article reviews the existing knowledge on the immunological activity of the fungal β-glucans and provides some recent results on the radioprotective and antimutagenic activity of the β-glucan isolated from the baker's yeast.
Water vapour sorption by vinyl caprolactam polymer samples with the molar masses in the range of ... more Water vapour sorption by vinyl caprolactam polymer samples with the molar masses in the range of 2.6—25 × 103 g mol−1 was investigated. Influence of the degree of polymerization on sorption was discovered for the oligomers. This dependence was not observed for the high-molar-mass polymers. The possible causes of this phenomenon are discussed.
Free-radical polymerization of N-vinylcaprolactam (VCL) in the presence of chain-transfer agents ... more Free-radical polymerization of N-vinylcaprolactam (VCL) in the presence of chain-transfer agents has been studied to obtain polyvinylcaprolactam possessing a predetermined relative molecular mass. Allyl compounds have been used as chain-transfer agents. Free-radical polymerization kinetics of VCL in the presence of allylbenzene and allylcaprolactam has been investigated as well as free-radical polymerization of VCL in isopropyl alcohol solution. The effect of reaction mixture composition on the rate and degree of polymerization has been studied, too. Possibility of synthesis of vinylcaprolactam oligomers with terminal hydroxyl groups has been demonstrated. Influence of a series of substituents at allylic compounds on kinetics of chain transfer has been investigated using quantum-chemical methods.
Russian Journal of Bioorganic Chemistry, Feb 1, 2007
3-Aminopropyl glycosides of α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-Dmannopyranosyl-(... more 3-Aminopropyl glycosides of α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-Dmannopyranosyl-(1 2)-α-D-mannopyranose, α-D-mannopyranosyl-(1 3)-α-D-mannopyranosyl-(1 2)α-D-mannopyranosyl-(1 2)-α-D-mannopyranose, and α-D-mannopyranosyl-(1 2)-[ α-D-mannopyranosyl-(1 3)]-α-D-mannopyranosyl-(1 2)-α-D-mannopyranosyl-(1 2)-α-D-mannopyranose were efficiently synthesized starting from ethyl 2-O-acetyl(benzoyl)-3,4,6-triO -benzyl-1-thio-α-D-mannopyranoside, ethyl 4,6-di-O-benzyl-2-O-benzoyl-1-thio-α-D-mannopyranoside, ethyl 4,6-di-O-benzyl-2,3-di-O-benzoyl-1-thio-α-D-mannopyranoside, and 2,3,4,6-tetra-O-benzoyl-α-D-mannopyranosyl bromide. The oligosaccharide chains synthesized correspond to the three structural types of side chains of mannan from Candida albicans cell wall. A conjugate of the third pentasaccharide with bovine serum albumin was prepared using the squarate method.
Experimental oncology, 2006
One of the advanced methodologies of the tumor therapy is the application of the so-called biolog... more One of the advanced methodologies of the tumor therapy is the application of the so-called biological response modifiers used for activation of the endogenous antitumor mechanisms and combined with classical cytotoxic agents. The aim of this work was the investigation of the effect of sulfoethylated (1-->3)-beta-D-glucan (SEG) in the treatment of experimental murine leukoses in combination with cyclophosphamide (CPA) and its ability to modulate the activity of lysosomal enzymes in tumor tissues. The solid forms of inoculated murine leukoses P388 and L1210/1 were transplantated to male DBA/2 mice. The therapy was performed by treating animals with CPA (Biokhimik, Saransk, Russia) alone or in combination with SEG (Institute of Chemistry, Slovak Academy of Sciences, Slovakia). CPA was administered in saline as a single intraperitoneal (ip) injection on the 10th day after tumor transplantation; SEG was administered to mice ip 3 days after tumor transplantation with the intervals in 3...
Carbohydrate Polymers, 1990
Cell wall o-mannans were isolated from all eight known pathogenic strains of genus Candida. Their... more Cell wall o-mannans were isolated from all eight known pathogenic strains of genus Candida. Their structural characterization was carried out by means of acetolysis and methylation analysis, as well as NMR spectroscopy. The results point out some common features and peculiarities of the structures of individual o-mannans. Differences observed in the structures of investigated mannans may be responsible for the differences in immunological properties of the corresponding yeast strains.
Plant Protection Science, 2017
Most of the experiments carried out in the area of plant protection have used chitin and chitosan... more Most of the experiments carried out in the area of plant protection have used chitin and chitosan obtained from the crustacean chitin which production is rather expensive. In our study we have applied the chitin-glucan complex prepared from the waste mycelia of filamentous fungi, from baker’s yeast. Five different polysaccharides have been used for the preparation of water-soluble compounds and the assay of their antifungal activity against plant pathogen Fusarium oxysporum. In the field experiments, application of the polysaccharides led to the diminished infestation as well as to significantly increased productivity of fresh weight of the plants (tomato). The results demonstrated that application of the polysaccharides led to increased production of cell wall and some outher and intermembrane-bound proteins. Although the nature of the observed proteins has not been yet established, it can be speculated that they represent some enzymes involved in the antiinfective defense mechanis...
Journal of Applied Polymer Science, 1995
Enzymatic and ultrasonic degradations of the carboxymethyl derivative of the p-1,3-Dglucan, isola... more Enzymatic and ultrasonic degradations of the carboxymethyl derivative of the p-1,3-Dglucan, isolated from the cell walls of baker's yeast Saccharomyces cerevisiae, are described. The samples obtained upon partial depolymerization of the two carboxymethylated glucans with the substitution degree of 0.56 and 0.91 were characterized by the distributions of their molecular weights and 13C-NMR spectra.
L'invention concerne un clathrate forme par association d'un derive d'acide hyaluroni... more L'invention concerne un clathrate forme par association d'un derive d'acide hyaluronique (a), d'un derive d'acide hyaluronique (b1) different de (a) capable de former un clathrate avec (a), et/ou d'un composant (b2) ne contenant pas de fraction d'acide hyaluronique mais pouvant former un clathrate avec (a); et son utilisation dans le domaine pharmaceutique.