Neoglycoconjugates: trade and art

2002 ◽  
Vol 69 ◽  
pp. 143-160 ◽  
Author(s):  
Nicolai V. Bovin
Keyword(s):  
Resonance Method ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Multiple Point ◽  
Point Interactions ◽  
Selectin Ligands ◽  
Carbohydrate Ligands ◽  
Multiple Ligands ◽  
Tethered Ligands ◽  
Kinetics Of

This chapter deals with the tendencies in design of multivalent neoglycoconjugates for glycobiology research and high-throughput profiling technologies, including cellular phenotyping. Soluble polyacrylamide (PAA) conjugates are remarkable owing to a variety of possibilities for synthesis and application. PAA is soluble and stable, and the molecule is flexible, PAA-tethered ligands are capable of adjusting to a receptor during multiple-point interactions and PAA does not bind to the cell surface. Synthesis provides unlimited diversity of the probe types (biotin, fluorescein, allyl, digoxygenin, 3H, radiolabelled I), glyco-particles, glyco-surfaces, multiarrays, immunogens etc. Several examples illustrate the most advanced applications. (i) Dynamic systems: the selectin ligands immobilized on the surface as sugar–PAA conjugates made the study of the kinetics of rolling in the model system possible. Carbohydrate ligands that are covalently attached to the chip as sugar–PAA conjugates are of use with the surface plasmon resonance method. (ii) Pseudoglycoprotein: some questions arise regarding the biologically active glycoproteins, e.g.: is a carbohydrate or peptide fragment responsible for the activity? We have proposed the approach that promotes to answer this and other questions. The pool of oligosaccharides that were spitted off a glycoprotein is attached to PAA resulting in a pseudoglycoprotein. (iii) Virtual (dynamic) glycotope: receptor-ligand recognition, such as that of P-selectin with its receptor P-selectin glycoprotein ligand 1, frequently involves molecular interactions at two distinct sites. Using P-selectin as a model, we developed an approach to discover novel ligands. PAA was synthesized with multiple ligands; a marked synergistic inhibitory effect was observed.

The effect of origin and physico-chemical properties on the kinetics of reduction of mixed NiO-Fe2O3 oxides with hydrogen

1986 ◽  
Vol 51 (10) ◽  
pp. 2098-2108 ◽  
Author(s):  
Milan Pospíšil ◽  
Jan Topinka
Keyword(s):  
Mixed Oxides ◽  
Mutual Influence ◽  
Spinel Phase ◽  
Chemical Properties ◽  
Inhibitory Effect ◽  
Chemical Parameters ◽  
Physico Chemical ◽  
Preliminary Annealing ◽  
Kinetics Of ◽  
Kinetics Of Reduction

We investigated the effect of origin and some physico-chemical parameters on the kinetics of reduction with hydrogen of two series of mixed NiO-Fe2O3 oxides differing by their composition, the character of their precursors (mixed crystalline nitrates and coprecipitated hydroxides) and their decomposition temperature.This effect manifested itself by different magnitudes of specific surfaces of the mixed oxides and coherent regions of present phases as well as by different oxidizing abilities of the surface and differences in morphology and phase composition of corresponding samples in both series investigated. Nonlinear or nonmonotonous composition dependences of physico-chemical parameters investigated point to a mutual influence of individual components, which is also a function of the system origin and which modifies its reactivity during its reduction with hydrogen. The kinetics of the reduction was studied thermogravimetrically at 320-410 °C. The reduction of oxides of the hydroxide origin is catalytically accelerated by primarily reduced nickel, whereas in corresponding samples of the nitrate series, the total NiO is bound to the spinel phase and the reduction is delayed. Experimental IR spectra, the effect of preliminary annealing and DTA of the mixed oxides point to an inhibitory effect of water, which is constitutionally bound in trace admixtures of the goethite phase, on the kinetics of reduction of samples in the hydroxide series.

scholarly journals Evaluation of Basidiomycetes Wild Strains Grown in Agro-Industrial Residues for Their Anti-Tyrosinase and Antioxidant Potential and for the Production of Biocatalysts

Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Anastasia Zerva ◽  
Nikolaos Tsafantakis ◽  
Evangelos Topakas
Keyword(s):  
Biomass Conversion ◽  
White Rot Fungi ◽  
Ligninolytic Enzymes ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
White Rot ◽  
Oxidative Enzymes ◽  
Industrial Residues ◽  
Pure Compounds ◽  
Wild Strains

White-rot basidiomycetes are the only microorganisms with the ability to produce both hydrolytic (cellulases and hemicellulases) and oxidative (ligninolytic) enzymes for degrading cellulose/hemicellulose and lignin. In addition, they produce biologically active natural products with important application in cosmetic formulations, either as pure compounds or as standardized extracts. In the present work, three wild strains of Basidiomycetes fungi (Pleurotus citrinopileatus, Abortiporus biennis and Ganoderma resinaceum) from Greek habitats were grown in agro-industrial residues (oil mill wastewater, and corn cob) and evaluated for their anti-tyrosinase and antioxidant activity and for the production of biotechnologically relevant enzymes. P. citrinopileatus showed the most interesting tyrosinase inhibitory activity, while A. biennis showed the highest DPPH(2,2-diphenyl-1-picryl-hydrazyl) scavenging potential. Corn cobs were the most appropriate carbon source for maximizing the inhibitory effect of fungal biomasses on both activities, while the use of oil mill wastewater selectively increased the anti-tyrosinase potential of P. citrinopileatus culture filtrate. All strains were found to be preferential lignin degraders, similarly to most white-rot fungi. Bioinformatic analyses were performed on the proteome of the strains P. citrinopileatus and A. biennis, focusing on CAZymes with biotechnological relevance, and the results were compared with the enzyme activities of culture supernatants. Overall, all three strains showed strong production of oxidative enzymes for biomass conversion applications.

Effect of Hypertonic Sucrose Upon the Immune Bactericidal Reaction

1970 ◽  
Vol 1 (1) ◽  
pp. 51-55
Author(s):  
Louis H. Muschel ◽  
Linda J. Larsen
Keyword(s):  
Cell Death ◽  
Cell Wall ◽  
Enzymatic Reaction ◽  
Inhibitory Effect ◽  
Lag Phase ◽  
Inner Membrane ◽  
Bactericidal Antibody ◽  
Kinetics Of ◽  
Free Serum ◽  
Supporting Structures

This study was performed to determine the mechanism whereby hypertonic sucrose inhibits the immune bactericidal reaction. Other investigators had postulated that the initial attack of complement (C) on the cell wall was followed with lysozyme-containing whole serum by an enzymatic reaction upon the peptidoglycan substrate resulting in cell death. In the absence of serum lysozyme, secondary lethal changes might occur from damage to the cell's inner membrane as a result of osmotic forces in the presence of a defective cell wall. Hypertonic sucrose giving rise to plasmolysis and protection of the inner membrane was presumed to differentially inhibit the immune response mediated by lysozyme-free serum. The experimental results observed in this investigation have indicated, however, that the inhibitory effect of sucrose upon the bactericidal reaction may be explained simply by its anticomplementary effect and not by any effect on the bacterial cell. This view was supported by the following observations: (i) the comparability of the inhibitory effect of sucrose upon the immune hemolytic and bactericidal reactions, (ii) the comparable percentage loss in bactericidal activity of whole serum and lysozyme-free serum resulting from hypertonic sucrose, (iii) bactericidal antibody titrations were relatively unaffected and C titrations markedly inhibited by sucrose, (iv) the inhibitory effect of sucrose on the bactericidal reaction was unaffected by prior growth of the organism in the presence of sucrose, (v) the kinetics of the bactericidal reactivity of lysozyme-free serum in hypertonic sucrose, compared with whole serum, did not reveal a prolonged lag phase with lysozyme-free serum, but simply diminished reactivity at all times. These observations are compatible with the view that the C attack upon the outer surface of gram-negative bacteria, which plays a part in the cell's permeability control, may account for cell death. In this regard, the immune bactericidal reaction is quite comparable to the lysis of red cells or nucleated cells by C despite the lack of overt lysis in bacteria, probably because of their underlying supporting structures.

Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

1971 ◽  
Vol 26 (7) ◽  
pp. 710-719 ◽  
Author(s):  
Kunhard Pollow ◽  
Barbara Pollow
Keyword(s):  
Hydrogen Transfer ◽  
Microsomal Fraction ◽  
Close Relation ◽  
Inhibitory Effect ◽  
Magnesium Ions ◽  
Michaelis Constant ◽  
Temperature Optimum ◽  
Optimum Ph ◽  
Kinetics Of ◽  
Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

scholarly journals FEATURES OF QUANTITATIVE MEASUREMENTS OF THE DYNAMIC MODULE OF ELASTICITY OF BINDERS IN OPTIMIZATION OF PRODUCTION TECHNOLOGY SEROGYPSUM COMPOSITE

2021 ◽  
pp. 86-92
Author(s):  
V.I. Tarasevych ◽  
◽  
Yu.G. Gasan ◽  
V.B. Dolgoshey ◽  
◽  
...  
Keyword(s):  
Time Dependence ◽  
Structure Formation ◽  
Elastic Properties ◽  
Physicochemical Characteristic ◽  
Resonance Method ◽  
Acoustic Resonance ◽  
Mechanical Action ◽  
Bending Vibrations ◽  
Damping Decrement ◽  
Kinetics Of

The paper considers the issues of studying the structure formation of binders during hardening to determine the optimal moments of mechanical action on gypsum concrete specimens, which makes it possible to optimize the technology of their impregnation with sulfur melt. The time dependence of the elastic modulus of a hardening, binder is its important physicochemical characteristic, since it is used to objectively identify the stages of structure formation, to simulate the processes occurring at each of the stages. It is noted that the method of acoustic resonance of bending vibrations, in the case of hardening binders, needs correction with respect to the measurement technique and interpretation of the results obtained. The kinetics of the resonance frequency of a sample consisting of a rigid cell and a dispersion poured into it is a function of the elastic properties of the cell, the dispersion itself, the contact zone of the dispersion with cell and therefore cannot be used for either qualitative or quantitative analysis of the kinetics of hardening. Taking into account the elasticity of cuvette is necessary to obtain reliable information. It has been established that in the presence of shrinkage or significant expansion of the binder, the study of structure formation by the resonance method should be carried out in plastic cuvettes. Regardless of shrinkage, the use of a cuvette requires compulsory consideration of its elastic properties. It is advisable to objectively distinguish the stages of structure formation on the basis of the kinetics of not the dynamic modulus of elasticity itself, but the rate of its change. The time dependence of the logarithmic damping decrement is also an important characteristic of the concrete structure. The studies carried out make it possible to obtain serogypsum composites with the necessary performance characteristics and to manufacture elements of architectural décor, wall fencing products of increased aesthetics, durability and reliability from them.

scholarly journals Antifungal activity of Mentha piperita and Carum carvi essential oils

2017 ◽  
pp. 201-207 ◽  
Author(s):  
Dragana Plavsic ◽  
Gordana Dimic ◽  
Djordje Psodorov ◽  
Dragan Psodorov ◽  
Ljubisa Saric ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Essential Oils ◽  
Inhibition Zone ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Mentha Piperita ◽  
Diffusion Method ◽  
Aromatic Plants ◽  
Disc Diffusion Method ◽  
Penicillium Aurantiogriseum

Aromatic plants are one of the most important sources of biologically active secondary metabolites, which possess various antimicrobial characteristics. The aim of this work was to examine the effect of antifungal activities of mint and caraway essential oils against the selected fungi. Eight species of molds were selected for antifungal testing: Alternaria alternata, Aspegillus flavus, A. niger, A. versicolor, Eurotium herbariorum, Penicillium aurantiogriseum, P. chrysogenum and P. expansum. Testing of essential oils antifungal activity against the selected species was conducted using the disc diffusion method by adding mint and caraway essential oils (0.5, 1, 5, and 10 ?l per disc). Antifungal activity of essential oils was expressed by the diameter of inhibition zone (mm). The most powerful effect of mint essential oil was recorded against E. herbariorum, as its growth was completely inhibited by the quantity of 5 ?l. The weakest inhibitory effect was observed against P. chrysogenum (inhibition zone 13.67 mm) by the quantity of 10 ?l. The most powerful antifungal activity of caraway was observed against E. herbariorum as growth was completely inhibited by the quantity of 10 ?l. The weakest inhibitory effect was observed against A. niger (inhibition zone 28 mm) by the quantity of 10 ?l.

scholarly journals Synthesis of New Antibiotics Derivatives by the Photocatalytic Method: A Screening Research

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1102
Author(s):  
Wojciech Baran ◽  
Ewa Masternak ◽  
Dominika Sapińska ◽  
Andrzej Sobczak ◽  
Ewa Adamek
Keyword(s):  
Quantum Yield ◽  
Biologically Active ◽  
Quantum Yields ◽  
Photocatalytic Process ◽  
Experimental Conditions ◽  
New Antibiotics ◽  
Photocatalytic Reactions ◽  
Kinetics Of ◽  
Derivatives Of ◽  
Uva Radiation

The aim of our study was to assess the possibility of using the photocatalytic process conducted in the presence of TiO2 to obtain new stable derivatives of antibacterial drugs. The possibility of introducing hydroxyl, chlorine, or bromide groups into antibiotics molecules was investigated. The experiments were conducted in aqueous solutions in the presence of TiO2-P25 as a photocatalyst, Cl− and Br- ions, and antibiotics belonging to eight different chemical classes. All experiments were initiated by UVa radiation. The kinetics of photocatalytic reactions and their quantum yield were determined, and the stable products were identified. All of the antibiotics used in the experiments underwent a photocatalytic transformation, and the quantum yields were in the range from 0.63 to 22.3%. The presence of Br- or FeCl3 significantly increased the efficiency of the photocatalytic process performed in the presence of TiO2, although Br- ion also acted as an inhibitor. Potentially biologically active chlorine derivatives from Trimethoprim, Metronidazole, Chloramphenicol, and bromine derivatives from Trimethoprim, Amoxicillin were obtained under experimental conditions. The potentially inactive halogen derivatives of Sulfamethoxazole and hydroxyl derivatives described in the literature were also identified.

Inhibition of endotoxin-induced lung inflammation by interleukin-10 gene transfer in mice

2000 ◽  
Vol 279 (5) ◽  
pp. L872-L877 ◽  
Author(s):  
Sujatha Dokka ◽  
Carl J. Malanga ◽  
Xianglin Shi ◽  
Fei Chen ◽  
Vincent Castranova ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Lung Inflammation ◽  
Transgene Expression ◽  
Tumor Necrosis ◽  
Interleukin 10 ◽  
Inhibitory Effect ◽  
Biologically Active ◽  
Tnf Α ◽  
Anti Inflammatory Cytokine ◽  
Necrosis Factor

Interleukin (IL)-10 is an anti-inflammatory cytokine that has great potential for use in the treatment of inflammatory and immune illnesses. In this study, gene transfer was used to induce IL-10 transgene expression in murine lungs for treatment of endotoxin-induced lung inflammation. Gene transfer was performed with a cytomegalovirus (CMV)-IL-10 plasmid with the aid of the liposomal agents LipofectAMINE and N-[1-(2,3-dioleoyl)propyl]- N, N, N-trimethylammonium methylsulfate (DOTAP). Administration of the endotoxin caused a marked increase in lung inflammation as indicated by increased tumor necrosis factor (TNF)-α release and neutrophil count. Pretreatment of the mice with IL-10 plasmid with and without LipofectAMINE had no inhibitory effect on lung inflammation and IL-10 transgene expression. LipofectAMINE by itself induced lung inflammation, an effect that was not observed with DOTAP. IL-10 plasmid when codelivered with DOTAP expressed biologically active IL-10 protein and caused a reduction in endotoxin-induced inflammation. Transgene expression was observed as early as 3 h after administration, peaked at 12 h, and declined thereafter. We conclude that IL-10 gene transfer is a feasible approach for the treatment of lung inflammation.

scholarly journals P-selectin mediates Ca(2+)-dependent adhesion of activated platelets to many different types of leukocytes: detection by flow cytometry

Blood ◽  
1992 ◽  
Vol 80 (1) ◽  
pp. 134-142 ◽  
Author(s):  
LG de Bruijne-Admiraal ◽  
PW Modderman ◽  
AE Von dem Borne ◽  
A Sonnenberg
Keyword(s):  
T Cells ◽  
Divalent Cations ◽  
Phosphatidyl Inositol ◽  
Cell Types ◽  
Inhibitory Effect ◽  
Immunofluorescence Assay ◽  
Cd8 Cells ◽  
Activated Platelets ◽  
Selectin Ligands ◽  
Different Types

Abstract Previous studies have shown that thrombin-activated platelets interact through the P-selectin with neutrophils and monocytes. To identify other types of leukocytes capable of such an interaction, eosinophils, basophils, and lymphocytes were isolated from whole blood. Binding of these cells to activated platelets was examined in a double immunofluorescence assay and the results show that activated platelets not only bind to neutrophils and monocytes, but also to eosinophils, basophils, and subpopulations of T lymphocytes. Using monoclonal antibodies (MoAbs) specific for subsets of T cells, we could further demonstrate that the T cells which bind activated platelets are natural killer (NK) cells and an undefined subpopulation of CD4+ and CD8+ cells. All these interactions were dependent on divalent cations and were completely inhibited by an MoAb against P-selectin. Thus, P- selectin mediates the binding of activated platelets to many different types of leukocytes. Studies with leukocytes treated with proteases or neuraminidase have shown that the structures recognized by P-selectin are glycoproteins carrying sialic acid residues. Because the loss of binding of activated platelets to neuraminidase-treated neutrophils was almost complete, but only partial to treated eosinophils, basophils, and monocytes, the latter cell types may have different P-selectin ligands in addition to those present on neutrophils. We found that two previously identified ligands for P-selectin, the oligosaccharides Le(x) and sialyl-Le(x), had little or no inhibitory effect on adhesion of activated platelets to leukocytes and that binding was not inhibited by MoAbs against these oligosaccharides. In addition, there was no correlation between the expression of Le(x) on several cell types and their capacity to bind activated platelets. In contrast, the expression of sialyl-Le(x) on cells was almost perfectly correlated with their ability to bind activated platelets. Thus, while Le(x) cannot be a major ligand for P-selectin, a possible role for sialyl-Le(x) in P- selectin-mediated adhesion processes cannot be dismissed. Finally, activated platelets were found to bind normally to monocytes and neutrophils of patients with paroxysmal nocturnal hemoglobulinuria (PNH) and to neutrophils from which phosphatidyl inositol (PI)-linked proteins had been removed by glycosylphosphatidyl inositol-specific phospholipase C (GPI-PLC) digestion. This suggests that at least part of the P-selectin ligands on these cells are not GPI-anchored.

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