Статті в журналах: "Oligo- polysaccharides"

1

Kadokawa, Jun-ichi. "α-Glucan Phosphorylase-Catalyzed Enzymatic Reactions Using Analog Substrates to Synthesize Non-Natural Oligo- and Polysaccharides". Catalysts 8, № 10 (19 жовтня 2018): 473. http://dx.doi.org/10.3390/catal8100473.

Повний текст джерела

Анотація:

As natural oligo- and polysaccharides are important biomass resources and exhibit vital biological functions, non-natural oligo- and polysaccharides with a well-defined structure can be expected to act as new functional materials with specific natures and properties. α-Glucan phosphorylase (GP) is one of the enzymes that have been used as catalysts for practical synthesis of oligo- and polysaccharides. By means of weak specificity for the recognition of substrates by GP, non-natural oligo- and polysaccharides has precisely been synthesized. GP-catalyzed enzymatic glycosylations using several analog substrates as glycosyl donors have been carried out to produce oligosaccharides having different monosaccharide residues at the non-reducing end. Glycogen, a highly branched natural polysaccharide, has been used as the polymeric glycosyl acceptor and primer for the GP-catalyzed glycosylation and polymerization to obtain glycogen-based non-natural polysaccharide materials. Under the conditions of removal of inorganic phosphate, thermostable GP-catalyzed enzymatic polymerization of analog monomers occurred to give amylose analog polysaccharides.

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Iravani, Siavash, and Rajender S. Varma. "Important Roles of Oligo- and Polysaccharides against SARS-CoV-2: Recent Advances." Applied Sciences 11, no. 8 (April 14, 2021): 3512. http://dx.doi.org/10.3390/app11083512.

Повний текст джерела

Анотація:

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-initiated outbreak of COVID-19 has spread rapidly around the world, posing a huge threat to public health. Natural oligo- and polysaccharides with low toxicity, good sustainability, high biocompatibility, respectable safety, immune regulation, and antiviral activity can be employed as promising candidates for the prevention and inhibition of viral infections, especially COVID-19. Glycosaminoglycans, marine polysaccharides, terrestrial plant polysaccharides, and some others have exhibited potential antiviral activity against pathogenic viruses, in the format of polysaccharide-centered vaccine adjuvants, nano-based structures, drug conveyance platforms, etc. In this review, significant recent advancements pertaining to the antiviral applications of oligo- and polysaccharides against SARS-CoV-2 are highlighted, including important challenges and future perspectives.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Vessella, Giulia, Serena Traboni, Antonio Laezza, Alfonso Iadonisi, and Emiliano Bedini. "(Semi)-Synthetic Fucosylated Chondroitin Sulfate Oligo- and Polysaccharides." Marine Drugs 18, no. 6 (June 1, 2020): 293. http://dx.doi.org/10.3390/md18060293.

Повний текст джерела

Анотація:

Fucosylated chondroitin sulfate (fCS) is a glycosaminoglycan (GAG) polysaccharide with a unique structure, displaying a backbone composed of alternating N-acetyl-d-galactosamine (GalNAc) and d-glucuronic acid (GlcA) units on which l-fucose (Fuc) branches are installed. fCS shows several potential biomedical applications, with the anticoagulant activity standing as the most promising and widely investigated one. Natural fCS polysaccharides extracted from marine organisms (Echinoidea, Holothuroidea) present some advantages over a largely employed antithrombotic drug such as heparin, but some adverse effects as well as a frequently found structural heterogeneity hamper its development as a new drug. To circumvent these drawbacks, several efforts have been made in the last decade to obtain synthetic and semi-synthetic fCS oligosaccharides and low molecular weight polysaccharides. In this Review we have for the first time collected these reports together, dividing them in two topics: (i) total syntheses of fCS oligosaccharides and (ii) semi-synthetic approaches to fCS oligosaccharides and low molecular weight polysaccharides as well as glycoclusters displaying multiple copies of fCS species.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Cuthbertson, Leslie, Veronica Kos, and Chris Whitfield. "ABC Transporters Involved in Export of Cell Surface Glycoconjugates." Microbiology and Molecular Biology Reviews 74, no. 3 (September 2010): 341–62. http://dx.doi.org/10.1128/mmbr.00009-10.

Повний текст джерела

Анотація:

SUMMARY Complex glycoconjugates play critical roles in the biology of microorganisms. Despite the remarkable diversity in glycan structures and the bacteria that produce them, conserved themes are evident in the biosynthesis-export pathways. One of the primary pathways involves representatives of the ATP-binding cassette (ABC) transporter superfamily. These proteins are responsible for the export of a wide variety of cell surface oligo- and polysaccharides in both Gram-positive and Gram-negative bacteria. Recent investigations of the structure and function of ABC transporters involved in the export of lipopolysaccharide O antigens have revealed two fundamentally different strategies for coupling glycan polymerization to export. These mechanisms are distinguished by the presence (or absence) of characteristic nonreducing terminal modifications on the export substrates, which serve as chain termination and/or export signals, and by the presence (or absence) of a discrete substrate-binding domain in the nucleotide-binding domain polypeptide of the ABC transporter. A bioinformatic survey examining ABC exporters from known oligo- and polysaccharide biosynthesis loci identifies conserved nucleotide-binding domain protein families that correlate well with themes in the structures and assembly of glycans. The familial relationships among the ABC exporters generate hypotheses concerning the biosynthesis of structurally diverse oligo- and polysaccharides, which play important roles in the biology of bacteria with different lifestyles.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Turdumambetov, K., D. A. Rakhimov, and M. Kh Malikova. "Oligo- and polysaccharides from Cousinia umbrosa." Chemistry of Natural Compounds 43, no. 3 (May 2007): 308–9. http://dx.doi.org/10.1007/s10600-007-0112-3.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

6

TANAKA, Toshio. "Enzymic Synthesis of Oligo- and Polysaccharides." Journal of the Japanese Society of Starch Science 40, no. 2 (1993): 203–8. http://dx.doi.org/10.5458/jag1972.40.203.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Pálvölgyi, Adrienn, Veronika Deák, Véréna Poinsot, Tibor Nagy, Enik Nagy, Ildikó Kerepesi, and Péter Putnoky. "Genetic Analysis of the rkp-3 Gene Region in Sinorhizobium meliloti 41: rkpY Directs Capsular Polysaccharide Synthesis to KR5 Antigen Production." Molecular Plant-Microbe Interactions® 22, no. 11 (November 2009): 1422–30. http://dx.doi.org/10.1094/mpmi-22-11-1422.

Повний текст джерела

Анотація:

Rhizobial surface polysaccharides, including capsular polysaccharides (KPS), are involved in symbiotic infection. The rkp-3 locus of Sinorhizobium meliloti 41 is responsible for the production of pseudaminic acid, one of the components of the KR5 antigen, a strain-specific KPS. We have extended the sequence determination and genetic dissection of the rkp-3 region to clarify the structure and function of the rkpY gene and to identify additional rkp genes. Except for rkpY, no other genes were found where mutation affected the KPS structure and symbiosis. These mutants show a unique phenotype producing a low molecular weight polysaccharide (LMW PS). Creating double mutants, we have shown that biosynthesis genes of the KR5 antigen except rkpZ are not necessary for the production of this LMW PS. Polysaccharide analysis of genetically modified strains suggests that rkpY has pleiotropic effects on polysaccharide production. It directs KPS synthesis to the KR5 antigen and influences lipo-oligo 3-deoxy-d-manno-2 octulosonic acid (Kdo) production in S. meliloti 41. In addition, rkpY suppresses the lipo-oligoKdo production when it is introduced into S. meliloti 1021.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Wang, Yvonne, Michael G. Gänzle, and Clarissa Schwab. "Exopolysaccharide Synthesized by Lactobacillus reuteri Decreases the Ability of Enterotoxigenic Escherichia coli To Bind to Porcine Erythrocytes." Applied and Environmental Microbiology 76, no. 14 (May 14, 2010): 4863–66. http://dx.doi.org/10.1128/aem.03137-09.

Повний текст джерела

Анотація:

ABSTRACT This study investigated the therapeutic potential of bacterial polysaccharides by employing a model system based on enteroxigenic Escherichia coli (ETEC)-induced hemagglutination of erythrocytes. Exopolysaccharides produced by strains of Lactobacillus reuteri inhibited ETEC-induced hemagglutination of porcine erythrocytes. No effect was observed for dextran produced from Weissella cibaria and commercially available oligo- and polysaccharides.

Стилі APA, Harvard, Vancouver, ISO та ін.

9

Li, Xiaowei, and Yan Zhao. "Synthetic glycosidases for the precise hydrolysis of oligosaccharides and polysaccharides." Chemical Science 12, no. 1 (2021): 374–83. http://dx.doi.org/10.1039/d0sc05338d.

Повний текст джерела

Анотація:

Synthetic glycosidases with a sugar-binding active site and a precisely positioned acidic group hydrolyze oligo- and polysaccharides selectively in hot water to afford desired sugar products in a single step.

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Uhr�n, Du?an, Jean-Robert Brisson, and DavidR Bundle. "Pseudo-3D NMR spectroscopy: Application to oligo- and polysaccharides." Journal of Biomolecular NMR 3, no. 3 (May 1993): 367–73. http://dx.doi.org/10.1007/bf00212523.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

GAROZZO, D. "ChemInform Abstract: MALDI Mass Spectra of Oligo- and Polysaccharides." ChemInform 29, no. 21 (June 22, 2010): no. http://dx.doi.org/10.1002/chin.199821277.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Christy, Alfred A. "Comparison of Water Adsorption Characteristics of Oligo and Polysaccharides of α-Glucose Studied by Near Infrared Spectroscopy". Advanced Materials Research 1035 (жовтень 2014): 476–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1035.476.

Повний текст джерела

Анотація:

The adsorption properties of water molecules on oligo and polysaccharides are attributed to the OH groups of the glucose rings in the molecules. The water molecules are adsorbed onto OH groups by hydrogen bond formation. Near infrared spectroscopic and gravimetric techniques were used in analysing the adsorption characteristics of malto-oligosaccharides and some polysaccharides. Near infrared spectra of the dry oligo and polysaccharides were acquired during the adsorption of water molecules at a relative humidity of 50-55%. The amounts of water adsorbed by the samples were also recorded by an analytical balance. Second derivative techniques were used in decomposing the OH combination frequencies of the adsorbed water molecules in the region 5300-5000 cm -1.The results indicate that the water molecules are adsorbed on to C2 and C3-OH groups at a higher rate compared to the adsorption onto C1-OH groups in the molecules. Adsorption also takes place onto the ethereal oxygen atoms in the glucose rings in malto-oligosaccarides. The gravimetric results show that the adsorption of water molecules increases with the number of glucose units in the malto-oligosaccharides except maltotriose which has the highest adsorption over a period of 75 minutes. Furthermore, the adsorption characteristics of amylose and amylopectin are similar.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Li, Jun, Chao Cai, Chendong Yang, Jianghua Li, Tiantian Sun, and Guangli Yu. "Recent Advances in Pharmaceutical Potential of Brown Algal Polysaccharides and their Derivatives." Current Pharmaceutical Design 25, no. 11 (August 6, 2019): 1290–311. http://dx.doi.org/10.2174/1381612825666190618143952.

Повний текст джерела

Анотація:

Marine plants, animals and microorganisms display steady growth in the ocean and are abundant carbohydrate resources. Specifically, natural polysaccharides obtained from brown algae have been drawing increasing attention owing to their great potential in pharmaceutical applications. This review describes the structural and biological features of brown algal polysaccharides, including alginates, fucoidans, and laminarins, and it highlights recently developed approaches used to obtain the oligo- and polysaccharides with defined structures. Functional modification of these polysaccharides promotes their advanced applications in biomedical materials for controlled release and targeted drug delivery, etc. Moreover, brown algal polysaccharides and their derivatives possess numerous biological activities with anticancer, anticoagulant, wound healing, and antiviral properties. In addition, we also discuss carbohydrate- based substrates from brown algae, which are currently in clinical and preclinical studies, as well as the marine drugs that are already on the market. The present review summarizes the recent development in carbohydratebased products from brown algae, with promising findings that could rapidly facilitate the future discovery of novel marine drugs.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Said, Joanna S., Edward Trybala, Staffan Görander, Maria Ekblad, Jan-Åke Liljeqvist, Eva Jennische, Stefan Lange, and Tomas Bergström. "The Cholestanol-Conjugated Sulfated Oligosaccharide PG545 Disrupts the Lipid Envelope of Herpes Simplex Virus Particles." Antimicrobial Agents and Chemotherapy 60, no. 2 (December 7, 2015): 1049–57. http://dx.doi.org/10.1128/aac.02132-15.

Повний текст джерела

Анотація:

ABSTRACTHerpes simplex virus (HSV) and many other viruses, including HIV, initiate infection of host cells by binding to glycosaminoglycan (GAG) chains of cell surface proteoglycans. Although GAG mimetics, such as sulfated oligo- and polysaccharides, exhibit potent antiviral activities in cultured cells, the prophylactic application of these inhibitors as vaginal microbicides failed to protect women upon their exposure to HIV. A possible explanation for this failure is that sulfated oligo- and polysaccharides exhibit no typical virucidal activity, as their interaction with viral particles is largely electrostatic and reversible and thereby vulnerable to competition with GAG-binding proteins of the genital tract. Here we report that the cholestanol-conjugated sulfated oligosaccharide PG545, but not several other sulfated oligosaccharides lacking this modification, exhibited virucidal activity manifested as disruption of the lipid envelope of HSV-2 particles. The significance of the virus particle-disrupting activity of PG545 was also demonstrated in experimental animals, as this compound, in contrast to unmodified sulfated oligosaccharide, protected mice against genital infection with HSV-2. Thus, PG545 offers a novel prophylaxis option against infections caused by GAG-binding viruses.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

Bohne, A., E. Lang, and C. W. von der Lieth. "SWEET - WWW-based rapid 3D construction of oligo- and polysaccharides." Bioinformatics 15, no. 9 (September 1, 1999): 767–68. http://dx.doi.org/10.1093/bioinformatics/15.9.767.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Stark, Timo, Daniela Keller, Kerstin Wenker, Hedda Hillmann, and Thomas Hofmann. "NonenzymaticC-Glycosylation of Flavan-3-ols by Oligo- and Polysaccharides." Journal of Agricultural and Food Chemistry 55, no. 23 (November 2007): 9685–97. http://dx.doi.org/10.1021/jf0719508.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Timotiwu, P. B., and N. Sakurai. "Identification of mono-, oligo-, and polysaccharides secreted from soybean roots." Journal of Plant Research 115, no. 2 (April 1, 2002): 77–85. http://dx.doi.org/10.1007/s102650200012.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Chester, T. L., and D. P. Innis. "Separation of oligo- and polysaccharides by capillary supercritical fluid chromatography." Journal of High Resolution Chromatography 9, no. 4 (April 1986): 209–12. http://dx.doi.org/10.1002/jhrc.1240090403.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

Dias-Tagliacozzo, Gláucia M., Nair M. Itaya, M. Angela Machado de Carvalho, Rita de Cássia L. Figueiredo-Ribeiro, and Sonia M. C. Dietrich. "Fructans and water suppression on intact and fragmented rhizophores of Vernonia herbacea." Brazilian Archives of Biology and Technology 47, no. 3 (July 2004): 363–73. http://dx.doi.org/10.1590/s1516-89132004000300005.

Повний текст джерела

Анотація:

In order to evaluate the involvement of fructans in drought tolerance, experiments were conducted using intact plants and excised rhizophores of Vernonia herbacea. The water content in rhizophores of intact plants was maintained for 30 days when plants were watered every 7 and 15 days, whereas plants remained alive up to 60 days without water. Total fructan, oligo- to polysaccharides ratio and mean molecular mass of polysaccharides increased in these plants indicating depolymerization of median size molecules. In apical fragments of rhizophores kept dry the oligosaccharides increased in relation to polysaccharides one day after excision in treated tissues. This was reflected in the HPLC profile of the oligosaccharides in which the proportion of free fructose and fructans with DP 4-10 increased markedly. Results indicate that fructan metabolism is involved in drought tolerance of V. herbacea.

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Chursin, Vyacheslav I., and Alena O. Zaitseva. "SYNTHESIS OF CHROME TANNING AGENT IN PRESENCE OF OLIGO - AND POLYSACCHARIDES." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 64, no. 5 (May 14, 2021): 63–70. http://dx.doi.org/10.6060/ivkkt.20216405.6350.

Повний текст джерела

Анотація:

The conditions for the synthesis of chrome tanning agent during the reduction of sodium dichromate with oligo - and polysaccharides have been investigated. The synthesis of the tanning agent is based on the reduction of hexavalent chromium Cr (VI) in the form of sodium dichromate with reducing agents from the class of vegetable oligo- and polysaccharides with a different sequence of their introduction into the reaction mixture in the presence of sulfuric acid. The introduction of sulfuric acid was carried out gradually to avoid overheating and splashing of the reaction mixture, since the reduction reaction is accompanied by a significant thermal effect. Glucose, maltodextrin and pectin were used as reducing agents. The properties of the obtained products were evaluated by spectrophotometry, conductometry, and analytical methods. It has been shown that the use of native pectin leads to the formation of a gel like mass due to the coordination of the functional groups of galacturonic acid, which is part of the pectin, with chromium atoms. Pretreatment of pectin with a citric acid solution and optimization of synthesis conditions made it possible to obtain a chromium tanning agent that does not contain unreduced chromium. The influence of oligosaccharides on the properties of chromium tanning agents, including their ability to dissolve, is considered. It is shown that the reduction of sodium dichromate with maltodextrin during the reaction results in the formation of incomplete oxidation products of the oligosaccharide, which cause the masking effect of the chromium complex and increase in the resistance of the tanning agent to the action of alkaline reagents used to increase in the basicity during tanning. Experimental samples of chrome tanning agent in dry form were obtained and their leatherprocessing characteristics were studied. The results of technological tests have confirmed the theoretical propositions, according to which the high hydrothermal stability of the leather semifinished product, the almost complete depletion of the processing solution and the required physical and mechanical properties of the finished leather are achieved by introducing the products of incomplete oxidation of oligosaccharides into the inner sphere of the chromium complex.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Delbianco, Martina, Andrew Kononov, Ana Poveda, Yang Yu, Tammo Diercks, Jesús Jiménez-Barbero, and Peter H. Seeberger. "Well-Defined Oligo- and Polysaccharides as Ideal Probes for Structural Studies." Journal of the American Chemical Society 140, no. 16 (April 6, 2018): 5421–26. http://dx.doi.org/10.1021/jacs.8b00254.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Williams, Alan G., and Colin G. Orpin. "Glycoside hydrolase enzymes present in the zoospore and vegetative growth stages of the rumen fungi Neocallimastix patriciarum, Piromonas communis, and an unidentified isolate, grown on a range of carbohydrates." Canadian Journal of Microbiology 33, no. 5 (May 1, 1987): 427–34. http://dx.doi.org/10.1139/m87-072.

Повний текст джерела

Анотація:

The rumen fungi Neocallimastix patriciarum, Piromonas communis, and a morphologically distinct but unidentified isolate were cultivated on the polysaccharides starch, cellulose, xylan, and their principal component monosaccharides and disaccharides, and the range and specific activities of the glycoside hdyrolases formed were monitored using gluco-oligo-saccharide and p-nitrophenyl glycoside substrates. A wide range of enzyme activities was detected in preparations from vegetative growth and zoospores of all three isolates. Enzyme activity was also present in the culture medium. The specific activities were affected by the carbohydrate source available in the growth medium, although the more active hydrolases involved in the degradation of plant structural and storage polysaccharides were formed on all seven carbohydrate sources evaluated. Enzyme activities were increased in the zoospore, vegetative, and extracellular preparations after growth on the appropriate structurally related disaccharide or polysaccharide. The hemicellulolytic glycosidases (α-L-arabinofuranosidase, β-D-xylosidase) were most active after growth on xylan, whereas α-/β-glucosidase activity was increased with the corresponding glucan as growth substrate. However, whereas wide-ranging β-glucosidase activity was detected following growth on maltose or starch, the α-glucosidase activities of P. communis were lower or undetectable in vegetative preparations grown on glucose or the β-glucans cellobiose and cellulose.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Corradini, Claudio, Antonella Cavazza, and Chiara Bignardi. "High-Performance Anion-Exchange Chromatography Coupled with Pulsed Electrochemical Detection as a Powerful Tool to Evaluate Carbohydrates of Food Interest: Principles and Applications." International Journal of Carbohydrate Chemistry 2012 (May 9, 2012): 1–13. http://dx.doi.org/10.1155/2012/487564.

Повний текст джерела

Анотація:

Specific HPLC approaches are essential for carbohydrate characterization in food products. Carbohydrates are weak acids with pKa values in the range 12–14 and, consequently, at high pH can be transformed into oxyanions, and can be readily separated using highly efficient anion-exchange columns. Electrochemical detection in HPLC has been proven to be a powerful analytical technique for the determination of compounds containing electroactive groups; pulsed amperometric detection of carbohydrates is favourably performed by taking advantage of their electrocatalytic oxidation mechanism at a gold working electrode in a basic media. High-performance Anion Exchange Chromatography (HPAEC) at high pH coupled with pulsed electrochemical detection (PED) is one of the most useful techniques for carbohydrate determination either for routine monitoring or research application. This technique has been of a great impact on the analysis of oligo- and polysaccharides. The compatibility of electrochemical detection with gradient elution, coupled with the high selectivity of the anion-exchange stationary phases, allows mixtures of simple sugars, oligo- and polysaccharides to be separated with high resolution in a single run. A few reviews have been written on HPAEC-PED of carbohydrates of food interest in the last years. In this paper the recent developments in this field are examined.

Стилі APA, Harvard, Vancouver, ISO та ін.

24

FAIJES, Magda, Tomoya IMAI, Vincent BULONE, and Antoni PLANAS. "In vitro synthesis of a crystalline (1 3,1 4)-beta-d-glucan by a mutated (1 3,1 4)-beta-d-glucanase from Bacillus." Biochemical Journal 380, no. 3 (June 15, 2004): 635–41. http://dx.doi.org/10.1042/bj20040145.

Повний текст джерела

Анотація:

Oligo- and poly-saccharides have a large number of important biological functions, and they occur in natural composite materials, such as plant cell walls, where they self-assemble during biosynthesis in a poorly understood manner. They can also be used for the formation of artificial composite materials with industrial applications. Fundamental and applied research in biology and nanobiotechnology would benefit from the possibility of synthesizing tailor-made oligo-/poly-saccharides. In the present paper, we demonstrate that such syntheses are possible using genetically modified glycoside hydrolases, i.e. glycosynthases. The ability of the endoglycosynthase derived from Bacillus (1→3,1→4)-β-d-glucanase to catalyse self-condensation of sugar donors was exploited for the in vitro synthesis of a regular polysaccharide. The specificity of the enzyme allowed the polymerization of α-laminaribiosyl fluoride via the formation of (1→4)-β-linkages to yield a new linear crystalline (1→3,1→4)-β-d-glucan with a repeating 4βG3βG unit. MS and methylation analyses indicated that the in vitro product consisted of a mixture of oligosaccharides, the one having a degree of polymerization of 12 being the most abundant. Morphological characterization revealed that the (1→3,1→4)-β-d-glucan forms spherulites which are composed of platelet crystals. X-ray and electron diffraction analyses allowed the proposition of a putative crystallographic structure which corresponds to a monoclinic unit cell with a=0.834 nm, b=0.825 nm, c=2.04 nm and γ=90.5°. The dimensions of the ab plane are similar to those of cellulose Iβ, but the length of the c-axis is nearly twice that of cellulose I. It is proposed that four glucose residues are present in an extended conformation along the c-axis of the unit cell. The data presented show that glycosynthases represent promising enzymic systems for the synthesis of novel polysaccharides with specific and controlled structures, and for the analysis in vitro of the mechanisms of polymerization and crystallization of polysaccharides.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Gomes, Tânia P., Vera L. D. Costa, Álvaro F. C. Vaz, and Rogério M. S. Simões. "Fractionation of broom (Cytisus striatus) biomass components via mild sulfite pretreatment and enzymatic hydrolysis." BioResources 16, no. 1 (November 9, 2020): 118–40. http://dx.doi.org/10.15376/biores.16.1.118-140.

Повний текст джерела

Анотація:

The potential of broom biomass to produce oligo- and monosaccharides was investigated using mild sulfite pretreatment conditions followed by enzymatic hydrolysis. Both treatments were analyzed via response surface methodology using an experimental central composite rotatable design 24 + star, which explored the following variables: sulfuric acid charge (0% to 3%), sodium sulfite charge (0% to 4%, maximum temperature (150 °C to 190 °C), and time at maximum temperature (0 min to 30 min). Oligo- and monosaccharides in the pretreatment hydrolysates were determined using high performance liquid chromatography. The amount of total extracted xylose, mannose, and galactose ranged from 3.5% to 15.8% of the initial biomass, while the model estimated optimal reaction conditions enabled the extraction of practically all hemicellulose in the raw material. However, the mildest pretreatment reaction conditions, with low temperature and low sulfuric acid charges, provided a hydrolysate where a major part of the extracted polysaccharides remained in oligomer form, enabling their separation by filtration. The cellulose-rich solid residue was submitted to enzymatic hydrolysis using a Novozymes® enzymatic cocktail. The enzymatic hydrolysis was successful, but some polysaccharides remained in the solid residue, mainly composed of lignin. An enzymatic yield of 60% was attained with no added sulfite in the pretreatment at 190 °C, despite the confirmed positive role of sulfur content in the solid residues.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Grachev, Alexey A., Alexey G. Gerbst, Alexander S. Shashkov, and Nikolay E. Nifantiev. "Application of modern NMR techniques for conformational analysis of oligo- and polysaccharides." Russian Chemical Reviews 78, no. 8 (August 31, 2009): 717–36. http://dx.doi.org/10.1070/rc2009v078n08abeh004061.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Chernykh, Ivan V., Alexey V. Shchulkin, Natalya M. Popova, Ekaterina E. Kirichenko, and Elena N. Yakusheva. "Vegetative polysaccharides: new target and direction of clinical use." Reviews on Clinical Pharmacology and Drug Therapy 16, no. 4 (December 15, 2018): 5–9. http://dx.doi.org/10.17816/rcf1645-9.

Повний текст джерела

Анотація:

P-glycoprotein (Pgp, ABCB1-protein) is a membrane efflux protein transporter located in hepatocytes, enterocytes, epithelial cells of the proximal renal tubules, histogematic barriers, and also in tumor cells, which releases the substrates from cells and plays an important role in pharmacokinetics of drugs. Inhibition of Pgp functional activity is promising for increasing the effectiveness of drug treatment of oncological diseases and pharmacoresistant epilepsy, but today no synthetic inhibitor of the transporter can be used in clinical practice because of side effects development. The aim of this review is to prove the relevance to use polysaccharides of plant origin, their derivatives and chemical modifications as effective, safe and cost-effective inhibitors of the transporter protein. The article describes the chemical structure of Pgp substrates and inhibitors, the ability to predict the drugs belonging to the transporter protein substrates or inhibitors. Some results of investigations of the belonging of oligo- and polysaccharides to Pgp substrates and inhibitors are presented. They are premises for carrying out appropriate experiments for polysaccharides of plant origin both in vitro and in vivo.

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Davies, Gideon J., and Spencer J. Williams. "Carbohydrate-active enzymes: sequences, shapes, contortions and cells." Biochemical Society Transactions 44, no. 1 (February 9, 2016): 79–87. http://dx.doi.org/10.1042/bst20150186.

Повний текст джерела

Анотація:

The enzyme-catalysed degradation of oligo and polysaccharides is of considerable interest in many fields ranging from the fundamental–understanding the intrinsic chemical beauty–through to the applied, including diverse practical applications in medicine and biotechnology. Carbohydrates are the most stereochemically-complex biopolymer, and myriad different natural polysaccharides have led to evolution of multifaceted enzyme consortia for their degradation. The glycosidic bonds that link sugar monomers are among the most chemically-stable, yet enzymatically-labile, bonds in the biosphere. That glycoside hydrolases can achieve a rate enhancement (kcat/kuncat) >1017-fold provides testament to their remarkable proficiency and the sophistication of their catalysis reaction mechanisms. The last two decades have seen significant advances in the discovery of new glycosidase sequences, sequence-based classification into families and clans, 3D structures and reaction mechanisms, providing new insights into enzymatic catalysis. New impetus to these studies has been provided by the challenges inherent in plant and microbial polysaccharide degradation, both in the context of environmentally-sustainable routes to foods and biofuels, and increasingly in human nutrition. Study of the reaction mechanism of glycoside hydrolases has also inspired the development of enzyme inhibitors, both as mechanistic probes and increasingly as therapeutic agents. We are on the cusp of a new era where we are learning how to dovetail powerful computational techniques with structural and kinetic data to provide an unprecedented view of conformational details of enzyme action.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Theodorou, Ilias, Pascal Courtin, Simon Palussière, Saulius Kulakauskas, Elena Bidnenko, Christine Péchoux, François Fenaille, et al. "A dual-chain assembly pathway generates the high structural diversity of cell-wall polysaccharides in Lactococcus lactis." Journal of Biological Chemistry 294, no. 46 (October 3, 2019): 17612–25. http://dx.doi.org/10.1074/jbc.ra119.009957.

Повний текст джерела

Анотація:

In Lactococcus lactis, cell-wall polysaccharides (CWPSs) act as receptors for many bacteriophages, and their structural diversity among strains explains, at least partially, the narrow host range of these viral predators. Previous studies have reported that lactococcal CWPS consists of two distinct components, a variable chain exposed at the bacterial surface, named polysaccharide pellicle (PSP), and a more conserved rhamnan chain anchored to, and embedded inside, peptidoglycan. These two chains appear to be covalently linked to form a large heteropolysaccharide. The molecular machinery for biosynthesis of both components is encoded by a large gene cluster, named cwps. In this study, using a CRISPR/Cas-based method, we performed a mutational analysis of the cwps genes. MALDI-TOF MS-based structural analysis of the mutant CWPS combined with sequence homology, transmission EM, and phage sensitivity analyses enabled us to infer a role for each protein encoded by the cwps cluster. We propose a comprehensive CWPS biosynthesis scheme in which the rhamnan and PSP chains are independently synthesized from two distinct lipid-sugar precursors and are joined at the extracellular side of the cytoplasmic membrane by a mechanism involving a membrane-embedded glycosyltransferase with a GT-C fold. The proposed scheme encompasses a system that allows extracytoplasmic modification of rhamnan by complex substituting oligo-/polysaccharides. It accounts for the extensive diversity of CWPS structures observed among lactococci and may also have relevance to the biosynthesis of complex rhamnose-containing CWPSs in other Gram-positive bacteria.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Qiu, Yanjun, Hong Jiang, Yueyang Dong, Yongzhen Wang, Hamed I. Hamouda, Mohamed A. Balah, and Xiangzhao Mao. "Expression and Biochemical Characterization of a Novel Fucoidanase from Flavobacteriumalgicola with the Principal Product of Fucoidan-Derived Disaccharide." Foods 11, no. 7 (April 1, 2022): 1025. http://dx.doi.org/10.3390/foods11071025.

Повний текст джерела

Анотація:

Fucoidan is one of the main polysaccharides of brown algae and echinoderm, which has nutritional and pharmacological functions. Due to the low molecular weight and exposure of more sulfate groups, oligo-fucoidan or fucoidan oligosaccharides have potential for broader applications. In this research, a novel endo-α-1,4-L-fucoidanase OUC-FaFcn1 which can degrade fucoidan into oligo-fucoidan was discovered from the fucoidan-digesting strain Flavobacterium algicola 12,076. OUC-FaFcn1 belongs to glycoside hydrolases (GH) family 107 and shows highest activity at 40 °C and pH 9.0. It can degrade the α-1,4 glycosidic bond, instead of α-1,3 glycosidic bond, of the fucoidan with a random tangent way to generate the principal product of disaccharide, which accounts for 49.4% of the total products. Therefore, OUC-FaFcn1 is a promising bio-catalyst for the preparation of fucoidan-derived disaccharide. These results further enrich the resource library of fucoidanase and provide the basis for the directional preparation of fucoidan-derived oligosaccharide with specific polymerization.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Adamiak, Beata, Maria Ekblad, Tomas Bergström, Vito Ferro, and Edward Trybala. "Herpes Simplex Virus Type 2 Glycoprotein G Is Targeted by the Sulfated Oligo- and Polysaccharide Inhibitors of Virus Attachment to Cells." Journal of Virology 81, no. 24 (September 10, 2007): 13424–34. http://dx.doi.org/10.1128/jvi.01528-07.

Повний текст джерела

Анотація:

ABSTRACT Variants of herpes simplex virus type 2 (HSV-2) generated by virus passage in GMK-AH1 cells in the presence of the sulfated oligosaccharide PI-88 were analyzed. Many of these variants were substantially resistant to PI-88 in their initial infection of cells and/or their cell-to-cell spread. The major alteration detected in all variants resistant to PI-88 in the initial infection of cells was a frameshift mutation(s) in the glycoprotein G (gG) gene that resulted in the lack of protein expression. Molecular transfer of the altered gG gene into the wild-type background confirmed that the gG-deficient recombinants were resistant to PI-88. In addition to PI-88, all gG-deficient variants of HSV-2 were resistant to the sulfated polysaccharide heparin. The gG-deficient virions were capable of attaching to cells, and this activity was relatively resistant to PI-88. In addition to having a drug-resistant phenotype, the gG-deficient variants were inefficiently released from infected cells. Purified gG bound to heparin and showed the cell-binding activity which was inhibited by PI-88. Many PI-88 variants produced syncytia in cultured cells and contained alterations in gB, including the syncytium-inducing L792P amino acid substitution. Although this phenotype can enhance the lateral spread of HSV in cells, it conferred no virus resistance to PI-88. Some PI-88 variants also contained occasional alterations in gC, gD, gE, gK, and UL24. In conclusion, we found that glycoprotein gG, a mucin-like component of the HSV-2 envelope, was targeted by sulfated oligo- and polysaccharides. This is a novel finding that suggests the involvement of HSV-2 gG in interactions with sulfated polysaccharides, including cell surface glycosaminoglycans.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Ghiulai, Roxana, Mirela Galusca, Ioana Sisu, Eugen Sisu, and Alina Zamfir. "High resolution mass spectrometric characterization of amino linked oligosaccharides — a preliminary study." Open Chemistry 11, no. 8 (August 1, 2013): 1309–19. http://dx.doi.org/10.2478/s11532-013-0265-9.

Повний текст джерела

Анотація:

AbstractIn this study maltose, maltotriose and maltotetraose were for the first time, coupled to 4,4′-methylenedianiline (MDA). The aim of this preliminary work was to test the feasibility of oligo- and polysaccharide coupling to MDA and the characterization of the coupling products by high resolution mass spectrometry (MS). (+) nanoESI in combination with a quadrupole time of flight (QTOF) MS in full scan (MS) and MS/MS was optimized first on underivatized maltose, maltotriose and maltotetraose. The optimal screening and sequencing conditions were further applied to the MDA-functionalized oligosaccharides. The obtained results revealed a straightforward MS detection of the functionalized oligomers, high sequence coverage and a fragmentation pathway with the formation of B and Y ions as well as the complementary C and Z ions along with a typical cleavage of the aglycon. We consider that this methodology is fully applicable also to polydisperse mixtures of long chain polysaccharides, which due to the large number of components and their size require a systematic method of development and testing.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Slobodova, D. A., R. M. Gorshkova, S. A. Pankov, B. S. Erova, V. Yu Elokhovskiy, E. F. Panarin, N. P. Novoselov, and D. Kh Khalikov. "RHEOLOGY OF WATER SOLUTIONS OF OLIGO- AND POLYSACCHARIDES IN A WIDE TEMPERATURE RANGE." Вестник Санкт-Петербургского государственного университета технологии и дизайна. Серия 1: Естественные и технические науки, no. 3 (2020): 102–6. http://dx.doi.org/10.46418/2079-8199_2020_3_15.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Deters, Alexandra M., Christian Lengsfeld, and Andreas Hensel. "Oligo- and polysaccharides exhibit a structure-dependent bioactivity on human keratinocytes in vitro." Journal of Ethnopharmacology 102, no. 3 (December 2005): 391–99. http://dx.doi.org/10.1016/j.jep.2005.06.038.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Mueller, Monika, Andrea Čavarkapa, Frank M. Unger, Helmut Viernstein, and Werner Praznik. "Prebiotic potential of neutral oligo- and polysaccharides from seed mucilage of Hyptis suaveolens." Food Chemistry 221 (April 2017): 508–14. http://dx.doi.org/10.1016/j.foodchem.2016.10.075.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Chernykh, Ivan V., Ekarina E. Kirichenko, Aleksey V. Shchulkin, Natalia M. Popova, and Anna A. Kotlyarova. "Possibilities of use of plant derived nonstarch polysaccharides in clinical practice." I.P. Pavlov Russian Medical Biological Herald 26, no. 2 (July 20, 2018): 305–16. http://dx.doi.org/10.23888/pavlovj20182305-316.

Повний текст джерела

Анотація:

Inhibition of Pglycoprotein transporter protein (ABCB1protein, Pgp) is a promising method to increase the effectiveness of pharmacotherapy in different pathologies: neoplastic diseases, epilepsy, cerebral circulation disorders. Pgp is a large transmembrane protein that provides efflux of a wide range of endo and xenobiotics from cells, and plays a significant role in pharmacokinetics of many medical drugs. Nowadays not a single synthetic inhibitor of the transporter is used in clinical practice due to nonselectivity of action, toxicity and high cost. Medicinal herbal remedies possess different pharmacological and therapeutic effects, rarely cause side effects and are economically accessible. This review presents the results of experiments in which affiliation of the oligo and polysaccharides to substrates and inhibitors of Pgp was analyzed, and which precondition further studies of other plant derived polysaccharides. Possibilities of using plant derived nonstarch polysaccharides in complex therapy of tumors are described, since along with potential inhibition of the transporter, they possess an antitumor effect and can also assist in correction of side effects of cytostatics. The prospects of using plant derived nonstarch polysaccharides for improvement of the effectiveness of neuroprotective therapy are presented, because they not only can increase the penetration of neuroprotective drugs across the bloodbrain barrier through Pgp inhibition, but also possess their own neuroprotective activity, as well as a number of pharmacological effects that can give a positive result in the complex treatment of brain pathologies. Thus investigations of plant nonstarch polysaccharides, their isolation and development of medical drugs on their basis is a promising direction of modern medicine.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Chernykh, Ivan V., Ekarina E. Kirichenko, Aleksey V. Shchulkin, Natalia M. Popova, and Anna A. Kotlyarova. "Possibilities of use of plant derived nonstarch polysaccharides in clinical practice." I.P. Pavlov Russian Medical Biological Herald 26, no. 2 (July 20, 2018): 305–16. http://dx.doi.org/10.23888/pavlovj2018262305-316.

Повний текст джерела

Анотація:

Inhibition of Pglycoprotein transporter protein (ABCB1protein, Pgp) is a promising method to increase the effectiveness of pharmacotherapy in different pathologies: neoplastic diseases, epilepsy, cerebral circulation disorders. Pgp is a large transmembrane protein that provides efflux of a wide range of endo and xenobiotics from cells, and plays a significant role in pharmacokinetics of many medical drugs. Nowadays not a single synthetic inhibitor of the transporter is used in clinical practice due to nonselectivity of action, toxicity and high cost. Medicinal herbal remedies possess different pharmacological and therapeutic effects, rarely cause side effects and are economically accessible. This review presents the results of experiments in which affiliation of the oligo and polysaccharides to substrates and inhibitors of Pgp was analyzed, and which precondition further studies of other plant derived polysaccharides. Possibilities of using plant derived nonstarch polysaccharides in complex therapy of tumors are described, since along with potential inhibition of the transporter, they possess an antitumor effect and can also assist in correction of side effects of cytostatics. The prospects of using plant derived nonstarch polysaccharides for improvement of the effectiveness of neuroprotective therapy are presented, because they not only can increase the penetration of neuroprotective drugs across the bloodbrain barrier through Pgp inhibition, but also possess their own neuroprotective activity, as well as a number of pharmacological effects that can give a positive result in the complex treatment of brain pathologies. Thus investigations of plant nonstarch polysaccharides, their isolation and development of medical drugs on their basis is a promising direction of modern medicine.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Cheng, Qian, Shuhuan Peng, Fangyi Li, Pengdi Cui, Chunxia Zhao, Xiaohui Yan, Tongchuan Suo, Chunhua Wang, Yongzhi He, and Zheng Li. "Quality Distinguish of Red Ginseng from Different Origins by HPLC–ELSD/PDA Combined with HPSEC–MALLS–RID, Focus on the Sugar-Markers." Separations 8, no. 11 (October 27, 2021): 198. http://dx.doi.org/10.3390/separations8110198.

Повний текст джерела

Анотація:

Red ginseng (RG) has been extensively utilized in Asian countries due to its pharmacological effects. For the quality evaluation of RG, small molecules, such as ginsenosides, have been widely considered as candidates of its quality markers (Q-markers), and various analytical techniques have been developed in order to identify these compounds. However, despite the efforts to analyze the hydrophobic constituents, it is worth pointing out that about 60% of the mass of RG is made of carbohydrates, including mono-, oligo- and polysaccharides. Consequently, the quality differentiation and identification of RG from the perspective of sugar-markers should be focused. High performance liquid chromatography and evaporative light scattering detector (HPLC–ELSD) method for the determination of disaccharides in RG was established. Furthermore, high performance size exclusion chromatography–multi-angle laser light scattering–refractive index detector (HPSEC–MALLS–RID) for the determination of molecular weight and high performance liquid chromatography photodiode array (HPLC–PDA) for the determination of compositional monosaccharides in RG polysaccharides were also established. HPLC–ELSD/PDA combined with HPSEC–MALLS–RID could be used to determine the contents of disaccharides, molecular weights, and compositional monosaccharides of RG polysaccharides, which could be used for quality control, and this is a new view on the sugar marker to quality differentiation of various origins of RG.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Kadokawa, Jun-ichi. "α-Glucan Phosphorylase: A Useful Catalyst for Precision Enzymatic Synthesis of Oligo- and Polysaccharides". Current Organic Chemistry 21, № 13 (11 травня 2017): 1192–204. http://dx.doi.org/10.2174/1385272821666170222124526.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Karboune, Salwa, Erin J. Davis, Ismail Fliss, and Eugenio Spadoni Andreani. "In-vitro digestion and fermentation of cranberry extracts rich in cell wall oligo/polysaccharides." Journal of Functional Foods 92 (May 2022): 105039. http://dx.doi.org/10.1016/j.jff.2022.105039.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Megherbi, M., B. Herbreteau, R. Faure, G. Dessalces, and M. ‐F Grenier‐Loustalot. "Solid Phase Extraction of Oligo‐ and Polysaccharides; Application to Maltodextrins and Honey Qualitative Analysis." Journal of Liquid Chromatography & Related Technologies 31, no. 7 (February 29, 2008): 1033–46. http://dx.doi.org/10.1080/10826070801924915.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Fort, Sébastien, Viviane Boyer, Lionel Greffe, Gideon J. Davies, Olga Moroz, Lars Christiansen, Martin Schülein, Sylvain Cottaz та Hugues Driguez. "Highly Efficient Synthesis of β(1 → 4)-Oligo- and -Polysaccharides Using a Mutant Cellulase". Journal of the American Chemical Society 122, № 23 (червень 2000): 5429–37. http://dx.doi.org/10.1021/ja9936520.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Nishi, Hiroyuki, and Yukari Kuwahara. "Enantiomer separation by capillary electrophoresis utilizing noncyclic mono-, oligo- and polysaccharides as chiral selectors." Journal of Biochemical and Biophysical Methods 48, no. 2 (April 2001): 89–102. http://dx.doi.org/10.1016/s0165-022x(01)00142-7.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Courtin, C. M., H. Van den Broeck, and J. A. Delcour. "Determination of reducing end sugar residues in oligo- and polysaccharides by gas–liquid chromatography." Journal of Chromatography A 866, no. 1 (January 2000): 97–104. http://dx.doi.org/10.1016/s0021-9673(99)01064-x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Sack, E. L. W., P. W. J. J. van der Wielen, and D. van der Kooij. "Utilization of oligo- and polysaccharides at microgram-per-litre levels in freshwater byFlavobacterium johnsoniae." Journal of Applied Microbiology 108, no. 4 (April 2010): 1430–40. http://dx.doi.org/10.1111/j.1365-2672.2009.04546.x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Greffe, Lionel, Morten T. Jensen, Claude Bosso, Birte Svensson, and Hugues Driguez. "Chemoenzymatic Synthesis of Branched Oligo- and Polysaccharides as Potential Substrates for Starch Active Enzymes." ChemBioChem 4, no. 12 (November 24, 2003): 1307–11. http://dx.doi.org/10.1002/cbic.200300692.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Ludwigs, U., A. Elgavish, J. D. Esko, E. Meezan та L. Rodén. "Reaction of unsaturated uronic acid residues with mercuric salts. Cleavage of the hyaluronic acid disaccharide 2-acetamido-2-deoxy-3-O-(β-d-gluco-4-enepyranosyluronic acid)-d-glucose". Biochemical Journal 245, № 3 (1 серпня 1987): 795–804. http://dx.doi.org/10.1042/bj2450795.

Повний текст джерела

Анотація:

Degradation of connective-tissue polysaccharides with bacterial or fungal eliminases and subsequent characterization of the reaction products are now part of standard methodology for the analysis of these compounds. However, the scope of preparative and analytical work based on the use of eliminases has been limited by the lack of procedures for specific removal of the unsaturated uronic acid residues generated in the eliminase reactions. In the present investigation, we have shown that these residues are cleaved by mercuric salts under mild conditions that are not likely to affect other structures in an oligo- or poly-saccharide molecule. Thus the disaccharide generated from hyaluronic acid by digestion with chondroitinase AC or ABC was cleaved into a keto acid and free N-acetylglucosamine within 10 min at room temperature upon exposure to 14 mM-mercuric acetate at pH 5. The reaction of the disaccharide with mercuric salts was used for ready determination of the distribution of radioactivity between the glucuronic acid and N-acetylglucosamine moieties in radioactive hyaluronic acid that had been synthesized by IMR-90 fibroblasts from 3H-labelled monosaccharides. When the precursor was [3H]galactose, over 95% of the incorporated radioactivity was found in the glucuronic acid moiety. In contrast, cells grown in the presence of [3H]glucosamine synthesized a polysaccharide in which almost all of the label was located in the N-acetylglucosamine units. It is apparent from these experiments that the reaction of unsaturated uronic acid residues with mercuric salts provides a new tool with potential for many applications in the study of the structure and metabolism of connective-tissue polysaccharides.

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Rastall, R. A., M. Diez-Municio, S. D. Forssten, B. Hamaker, A. Meynier, F. Javier Moreno, F. Respondek, B. Stah, K. Venema, and M. Wiese. "Structure and function of non-digestible carbohydrates in the gut microbiome." Beneficial Microbes 13, no. 2 (June 18, 2022): 95–168. http://dx.doi.org/10.3920/bm2021.0090.

Повний текст джерела

Анотація:

Together with proteins and fats, carbohydrates are one of the macronutrients in the human diet. Digestible carbohydrates, such as starch, starch-based products, sucrose, lactose, glucose and some sugar alcohols and unusual (and fairly rare) α-linked glucans, directly provide us with energy while other carbohydrates including high molecular weight polysaccharides, mainly from plant cell walls, provide us with dietary fibre. Carbohydrates which are efficiently digested in the small intestine are not available in appreciable quantities to act as substrates for gut bacteria. Some oligo- and polysaccharides, many of which are also dietary fibres, are resistant to digestion in the small intestines and enter the colon where they provide substrates for the complex bacterial ecosystem that resides there. This review will focus on these non-digestible carbohydrates (NDC) and examine their impact on the gut microbiota and their physiological impact. Of particular focus will be the potential of non-digestible carbohydrates to act as prebiotics, but the review will also evaluate direct effects of NDC on human cells and systems.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Prosky, Leon. "Inulin and Oligofructose Are Part of the Dietary Fiber Complex." Journal of AOAC INTERNATIONAL 82, no. 2 (March 1, 1999): 223–26. http://dx.doi.org/10.1093/jaoac/82.2.223.

Повний текст джерела

Анотація:

Abstract Dietary fiber has been defined as the remnants of plant cells resistant to hydrolysis by human alimentary enzymes. Its main chemical constituents are hemicelluloses, celluloses, lignin, pectins, gums, and waxes. The U.S. Food and Drug Administration and the U.S. Department of Agriculture determine compliance with nutritional labeling regulations for dietary fiber by use of the existing AOAC INTERNATIONAL methods for total dietary fiber. The above compounds are readily detected by these methods. However, some oligo and polysaccharides are resistant to human alimentary enzymes and do not precipitate in 78% ethanol, the usual reagent for precipitating dietary fiber in analytical procedures. Some of these saccharides, termed fructans, are inulin and oligofructose. They possess many physiological attributes normally associated with dietary fiber. Inulin is a mixture of oligo and polysaccharides composed of fructose moieties joined by β(2→1) linkages in linear chains. Almost each chain ends with a glucose moiety. Oligofructose is a synonym for fructooligosaccharides, with fructose moieties joined by β(2→1) linkages, as in inulin. Not all molecules have a glucose unit, and the chain length is less than 10 units. A method for inulin and oligofructose was developed andapproved official first action by AOAC INTERNATIONAL in early 1997. It involves extraction of sample and treatment of the extract with amyloglucosidase followed by fructozyme (Fructozyme™ Enzyme Process Division, Novo Nordisk, Novo Industry, Copenhagen, Denmark). The sugars released in each of the 3 steps are measured by anion-exchange chromatography. The concentration of fructans is calculated as the difference of sugars, glucose and fructose, after the enzymatic treatments and the initial sample. The repeatability standard deviations for inulin and oligofructose ranged from 2.9 to 5.8% and the reproducibility standard deviations ranged

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Tungland, B. C., and D. Meyer. "Nondigestible Oligo- and Polysaccharides (Dietary Fiber): Their Physiology and Role in Human Health and Food." Comprehensive Reviews in Food Science and Food Safety 1, no. 3 (October 2002): 90–109. http://dx.doi.org/10.1111/j.1541-4337.2002.tb00009.x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Oligo- polysaccharides"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями