ISOLATION AND SOME STRUCTURAL FEATURES OF A POLYSACCHARIDE FROM BIRCH SAP

1964 ◽  
Vol 42 (9) ◽  
pp. 2093-2100 ◽  
Author(s):  
B. Urbas ◽  
G. A. Adams ◽  
C. T. Bishop
Keyword(s):  
Glucuronic Acid ◽  
Xylem Sap ◽  
Periodate Oxidation ◽  
Structural Features ◽  
The Other ◽  
Molar Ratio ◽  
Plant Products ◽  
End Groups

A polysaccharide, precipitated by cetyltrimethylammonium hydroxide from the non-dialyzable portion of birch xylem sap, contained D-galactose, D-mannose, and D-glucose in a molar ratio of 2:1.4:1 and small amounts of D-glucuronic acid. Periodate oxidation studies indicated that the polysaccharide was branched and contained a high proportion of periodate-resistant monosaccharides. This was confirmed by methylation and hydrolysis which yielded 2,3,4,6-tetra-O-methyl-D-glucose (2.0 moles); 2,4,6-tri-O-methyl-D-mannose (0.9 mole); 2,4,6-tri-O-methyl-D-galactose (3.8 moles); unidentified tri-O-methyl hexose (1.2 moles); and 3,5-di-O-methyl-D-mannose (1.8 moles). The latter, a new di-O-methyl-D-mannose, snowed the presence of D-mannofuranose units in the polysaccharide. This, together with the 1 → 3 linked α-D-mannopyranose units, makes this polysaccharide unique among plant products. Immunochemical tests with antipneumococcal and antiparatyphoid B horse sera confirmed the presence of D-glucuronic acid and D-glucopyranose non-reducing end groups and supported the other structural conclusions by showing that there were few, if any, 1 → 4 and 1 → 6 linked D-mannopyranose units or D-galactopyranose non-reducing end groups.

STRUCTURAL FEATURES OF TWO EXTRACELLULAR POLYSACCHARIDES FROM SERRATIA MARCESCENS

1965 ◽  
Vol 43 (11) ◽  
pp. 2929-2939 ◽  
Author(s):  
Robert Young ◽  
G. A. Adams
Keyword(s):  
Serratia Marcescens ◽  
Culture Filtrate ◽  
Cetyltrimethylammonium Bromide ◽  
Main Chain ◽  
Deae Cellulose ◽  
Structural Features ◽  
Ethanol Solution ◽  
Molar Ratio ◽  
Extracellular Polysaccharides ◽  
End Groups

A polysaccharide insoluble in acidified ethanol solution has been isolated from a culture filtrate of Serratia marcescens. Fractionation by cetyltrimethylammonium bromide ("Cetavlon") and by diethylaminoethyl (DEAE) cellulose yielded a polysaccharide which was electrophoretically homogeneous and contained D-glucose, L-rhamnose, D-galactose, L-glycero-D-mano-heptose, D-glycero-D-manno-heptose, glucosamine, and galactosamine in an approximate molar ratio of 6.5:3.5:0.5:1.0:0.5:1.0:0.2. However, following methylation it was found that the fully methylated polysaccharide could be fractionated by organic solvents into a rhamnoglucan and a heptoglucan. Both polysaccharides contained lipid material consisting mainly of hydroxy myristic acid and hydroxy lauric acid. The main chain of the rhamnoglucan was composed of (1 → 3) linked L-rhamnopyranose units and (1 → 4) linked D-glucose units with the non reducing end groups being D-glucose; some branching occurred through D-glucose units. The heptoglucan was composed mainly of chains of (1 → 4) linked D-glucose units with smaller amounts of (1 → 6) linked D-glucose and (1 → 2) linked D-glycero-D-manno-heptose units; these chains were terminated by D-glucopyranose and L-glycero-D-manno-heptose end groups.

AN EXTRACELLULAR POLYSACCHARIDE FROM GIBBERELLA FUJIKUROI (FUSARIUM MONILIFORME)

1961 ◽  
Vol 39 (8) ◽  
pp. 1683-1694 ◽  
Author(s):  
I. R. Siddiqui ◽  
G. A. Adams
Keyword(s):  
Fusarium Moniliforme ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Extracellular Polysaccharide ◽  
Gibberella Fujikuroi ◽  
Molar Ratio ◽  
Glucose Medium ◽  
Mannuronic Acid ◽  
Acid Protein ◽  
Furanose Form

Growth of Gibberellafujikuroi (Fusariummoniliforme) on a glucose medium produced au extracellular polysaccharide containing D-glucose, D-mannose, D-galactose, D-glucuronic acid (molar ratio 1.0:1.1:1.3:0.6), and possibly D-mannuronic acid. Protein was retained tenaciously by the polysaccharide and several deproteinization methods reduced the nitrogen content only slightly. Methylation studies showed that the polysaccharide was highly branched with D-glucose and D-mannose forming the non-reducing ends in the molecule. Most of the D-mannose and D-galactose units were joined by 1 → 2 and 1 → 6 linkages with some branching also at C2 and C6 positions; D-galactose occurred exclusively in the furanose form. D-Glucose units were joined by 1 → 2 and 1 → 3 linkages. The D-glucuronic acid residues were mainly non-terminal and were attached to both D-galactose and D-mannose units. Periodate oxidation studies supported the foregoing conclusions.

THE STRUCTURE OF A SYNTHETIC GLUCAN: I. GENERAL STRUCTURAL FEATURES

1962 ◽  
Vol 40 (6) ◽  
pp. 1196-1200 ◽  
Author(s):  
G. G. S. Dutton ◽  
A. M. Unrau
Keyword(s):  
Petroleum Ether ◽  
Acid Hydrolysis ◽  
Direct Evidence ◽  
Periodate Oxidation ◽  
Structural Features ◽  
Degree Of Polymerization ◽  
Molar Ratio ◽  
Partial Hydrolysis ◽  
Large Numbers ◽  
Hydrolysis Of

Only D-glucose was obtained on acid hydrolysis of the glucan. Periodate oxidation released formaldehyde, which was believed to arise from C6 of D-glucofuranose units. From the additional formaldehyde liberated from the borohydride-reduced glucan the degree of polymerization was estimated to be about 165. Complete hydrolysis of the derived polyalcohol gave glycerol, erythritol, D-glucose, and D-xylose. Partial hydrolysis gave glycerol, erythritol, and at least seven non-reducing oligosaccharides. Direct evidence for the existence of relatively large numbers of 1 → 6 and 1 → 4 linkages was found, together with smaller numbers of 1 → 2 linkages. The methylated glucan was freely soluble in chloroform – petroleum ether (5:95), and hydrolysis gave tetra, tri, di, and mono-O-methyl-D-glucoses in a 6:6:3:1 molar ratio.

THE CONSTITUTION OF A POLYURONIDE HEMICELLULOSE FROM WHEAT STRAW

1952 ◽  
Vol 30 (9) ◽  
pp. 698-710 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Uronic Acid ◽  
Glucuronic Acid ◽  
Periodate Oxidation ◽  
Reducing Power ◽  
Molar Ratio ◽  
Acid Complex ◽  
Glycosidic Bonds ◽  
A Chain ◽  
End Group

The structure of a polyuronide hemicellulose from wheat straw containing xylose, arabinose, and hexuronic acid units has been investigated. Graded hydrolysis preferentially removed anhydro-L-arabinose units leaving a xylan to which uronic acid units were attached. Methylation and hydrolysis yielded 2,3,4-trimetliyl xylose (2.7%) indicating one nonreducing end group per 37 units; 2,3,5-trimethyl-L-arabinose, 2,3-dimethyl-D-xylose, and 2-methyl-D-xylose were found in a molar ratio 1:5:1. In addition, a methylated uronic acid complex was recovered which on extensive hydrolysis yielded an aldobiuronic acid. The latter, on reduction with sodium borohydride, yielded 2,3,4-trimethyl glucose (1 mole) and 2-methyl xylose (1 mole); the structure 2-methyl 3[2,3,4-trimethyl α-D-glucuronosido] D-xylose was therefore indicated for the methylated aldobiuronic acid.A structure for the hemicellulose is proposed which consists of approximately 32 anhydro-D-xylose units linked β 1,4- in a chain to which five anhydro-L-arabinose and three D-glucuronic acid units are attached as side groups by 1,3-glycosidic bonds. Results of periodate oxidation and estimation of reducing power support the proposed structure.

Cytochemical Studies of Cell Wall Biosynthesis in Staphylococcus Aureus

1972 ◽  
Vol 30 ◽  
pp. 328-329
Author(s):  
Masaatsu Koike ◽  
Koichi Nakashima ◽  
Kyoko Iida
Keyword(s):  
Staphylococcus Aureus ◽  
Periodate Oxidation ◽  
Early Time ◽  
The Other ◽  
Penicillin G ◽  
Cell Wall Biosynthesis ◽  
Septal Wall ◽  
Peptidoglycan Biosynthesis ◽  
Gram Positive Bacteria ◽  
Cross Linkage

Penicillin exerts the activity to inhibit the peptide cross linkage between each polysaccharide backbone at the final stage of wall-peptidoglycan biosynthesis of bacteria. Morphologically, alterations of the septal wall and mesosome in gram-positive bacteria, which were occurred in early time after treatment with penicillin, have been observed. In this experiment, these alterations were cytochemically investigated by means of silver-methenamine staining after periodate oxidation, which is applied for detection of localization of wall mucopolysaccharide.Staphylococcus aureus strain 209P treated with 100 u/ml of penicillin G was divided into two aliquotes. One was fixed by Kellenberger-Ryter's OSO4 fixative at 30, 60 and 120 min after addition of the antibiotic, dehydrated through alcohol series, and embedded in Epon 812 (Specimen A). The other was fixed by 21 glutaraldehyde, dehydrated through glycolmethacrylate series and embedded in glycolmethacrylate mixture, according to Bernhard's method (Specimen B).

Binding of lead and copper(II) cations to hemicelluloses of rye bran

1986 ◽  
Vol 51 (10) ◽  
pp. 2250-2258 ◽  
Author(s):  
Rudolf Kohn ◽  
Zdena Hromádková ◽  
Anna Ebringerová
Keyword(s):  
Uronic Acid ◽  
Equilibrium Solution ◽  
Glucuronic Acid ◽  
The Other ◽  
Carboxyl Groups ◽  
Stoichiometric Ratio ◽  
Molar Ratios ◽  
Free Ions ◽  
Uronic Acid Content ◽  
The Relationship

Several fractions of acid hemicelluloses isolated from rye bran were characterized by molar ratios of saccharides (D-Xyl, L-Ara, D-Glc, D-Gal) and 4-O-methyl-D-glucuronic acid and protein content. Binding of Pb2+ and Cu2+ ions to these acid polysaccharides was considered according to function (M)b = f([M2+]f), expressing the relationship between the amount of metal (M)b bound to 1 g of the substance and the concentration of free ions [M2+]f in the equilibrium solution and according to the association degree β of these cations with carboxyl groups of uronic acid at a stoichiometric ratio of both components in the system under investigation. Acid hemicelluloses contained only a very small portion of uronic acid ((COOH) 0.05-0.18 mmol g-1); the model polysaccharide, 4-O-methyl-D-glucurono-D-xylan of beech, was substantially richer in uronic acid content ((COOH) 0.73 mmol g-1). Consequently, the amount of lead and copper bound to acid hemicelluloses is very small ((M)b 0.017-0.025 mmol g-1) at [M2+]f = 0.10 mmol l-1. On the other hand, much greater amount of cations ((M)f 0.09-0.10 mmol g-1) was bound to the glucuronoxylan. The association degree β was like with the majority of samples (β = 0.31-0.38). The amount of lead and copper(II) bound to acid hemicelluloses from rye bran is several times lower than that bound to dietary fiber isolated from vegetables (cabbage, carrot), rich in pectic substances.

scholarly journals Copper(II) 2,2-Bis(Hydroxymethyl)Propionate Coordination Compounds with Hexamethylenetetramine: From Mononuclear Complex to One-Dimensional Coordination Polymer

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3358
Author(s):  
Sadaf Rauf ◽  
Agata Trzesowska-Kruszynska ◽  
Tomasz Sierański ◽  
Marcin Świątkowski
Keyword(s):  
Coordination Polymer ◽  
Coordination Compounds ◽  
Structural Diversity ◽  
Structural Features ◽  
Mononuclear Complex ◽  
Molar Ratio ◽  
One Dimensional ◽  
1D Coordination Polymer ◽  
Copper Coordination ◽  
Stretching Vibrations

Three new copper coordination compounds derived from 2,2-bis(hydroxymethyl)propionic acid (dmpa) and hexamethylenetetramine (hmta) were obtained and their crystal structures were determined. The stoichiometry of the reagents applied in the syntheses reflects the metal to ligand molar ratio in the formed solid products. Due to the multiple coordination modes of the used ligands, wide structural diversity was achieved among synthesized compounds, i.e., mononuclear [Cu(dmp)2(hmta)2(H2O)] (1), dinuclear [Cu2(dmp)4(hmta)2] (2), and 1D coordination polymer [Cu2(dmp)4(hmta)]n (3). Their supramolecular structures are governed by O—H•••O and O—H•••N hydrogen bonds. The compounds were characterized in terms of absorption (UV-Vis and IR) and thermal properties. The relationships between structural features and properties were discussed in detail. Owing to discrepancies in the coordination mode of a dmp ligand, bidentate chelating in 1, and bidentate bridging in 2 and 3, there is a noticeable change in the position of the bands corresponding to the stretching vibrations of the carboxylate group in the IR spectra. The differences in the structures of the compounds are also reflected in the nature and position of the UV-Vis absorption maxima, which are located at lower wavelengths for 1.

Quo Vadis Tyrannosaurus?: The Future of Dinosaur Studies

1989 ◽  
Vol 2 ◽  
pp. 175-183 ◽  
Author(s):  
Daniel J. Chure
Keyword(s):  
Public Relations ◽  
Earth Science ◽  
Structural Features ◽  
The Other ◽  
Canada Geese ◽  
New Genera ◽  
Research Activity ◽  
Detailed Understanding ◽  
The Public ◽  
Quo Vadis

“Although I work a lot with fossils in my own research on fishes, I do not care to be called a paleontologist; and I am turned off by many aspects of the public-relations hoopla surrounding paleontology, especially dinosaurs…. One could easily argue that the schools' fascination with dinosaurs might also detract from the other aspects of earth science and biological science and, in the end, weaken paleontology's image as an activity for hard-nosed grown-ups.”K.S. Thomson, 1985: p. 73“Let dinosaurs be dinosaurs. Let the Dinosauria stand proudly alone, a Class by itself. They merit it. And let us squarely face the dinosaurness of birds and the birdness of the Dinosauria. When the Canada geese honk their way northward, we can say: “The dinosaurs are migrating, it must be spring!”R.T. Bakker, 1986: p. 462It is a now oft-repeated statement that we are in the Second Golden Age of dinosaur studies. This may at first seem to be yet another overstatement by dinosaur fanatics; in fact, it is substantiated on a number of fronts. Research activity is certainly at an all-time high, with resident dinosaur researchers on every continent (except Antarctica) and dinosaurs known from every continent (including Antarctica). This activity has resulted in a spate of discoveries, including not only new genera and species, but entirely new types of dinosaurs, such as the segnosaurs. Well-known groups are producing surprises, such as armored sauropods and sauropods bearing tail clubs. Good specimens of previously named genera are revealing unsuspected structural features that almost defy explanation, as in the skull of Oviraptor. However, dinosaur studies extend far beyond the traditional emphasis on dinosaur morphology, and encompass paleobiogeography, paleoecology, taphonomy, physiology, tracks, eggs, histology, and extinction, among others. In some cases, several of these studies can be applied to a single taxon or locality to give us a fairly detailed understanding of the paleobiology of some species.

scholarly journals IgA: Structure, Function, and Developability

Antibodies ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 57 ◽  
Author(s):  
Patrícia de Sousa-Pereira ◽  
Jenny M. Woof
Keyword(s):  
Monoclonal Antibodies ◽  
Structure Function ◽  
Immunoglobulin A ◽  
Structural Features ◽  
The Other ◽  
Immune Defence ◽  
Major Site ◽  
Mucosal Surfaces ◽  
Serum Iga ◽  
Antibody Class

Immunoglobulin A (IgA) plays a key role in defending mucosal surfaces against attack by infectious microorganisms. Such sites present a major site of susceptibility due to their vast surface area and their constant exposure to ingested and inhaled material. The importance of IgA to effective immune defence is signalled by the fact that more IgA is produced than all the other immunoglobulin classes combined. Indeed, IgA is not just the most prevalent antibody class at mucosal sites, but is also present at significant concentrations in serum. The unique structural features of the IgA heavy chain allow IgA to polymerise, resulting in mainly dimeric forms, along with some higher polymers, in secretions. Both serum IgA, which is principally monomeric, and secretory forms of IgA are capable of neutralising and removing pathogens through a range of mechanisms, including triggering the IgA Fc receptor known as FcαRI or CD89 on phagocytes. The effectiveness of these elimination processes is highlighted by the fact that various pathogens have evolved mechanisms to thwart such IgA-mediated clearance. As the structure–function relationships governing the varied capabilities of this immunoglobulin class come into increasingly clear focus, and means to circumvent any inherent limitations are developed, IgA-based monoclonal antibodies are set to emerge as new and potent options in the therapeutic arena.

Degradation of chlorpyriphos in water by advanced oxidation processes

2010 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Murillo ◽  
J. Sarasa ◽  
M. Lanao ◽  
J. L. Ovelleiro
Keyword(s):  
Reaction Time ◽  
Light Source ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
The Other ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Other Hand ◽  
Initial Ph

The degradation of chlorpyriphos by different advanced oxidation processes such as photo-Fenton, TiO2, TiO2/H2O2, O3 and O3/H2O2 was investigated. The photo-Fenton and TiO2 processes were optimized using a solar chamber as light source. The optimum dosages of the photo-Fenton treatment were: [H2O2]=0.01 M; [Fe3 + ]=10 mg l−1; initial pH = 3.5. With these optimum conditions total degradation was observed after 15 minutes of reaction time. The application of sunlight was also efficient as total degradation was achieved after 60 minutes. The optimum dosage using only TiO2 as catalyst was 1,000 mg l−1, obtaining the maximum degradation at 20 minutes of reaction time. On the other hand, the addition of 0.02 M of H2O2 to a lower dosage of TiO2 (10 mg l−1) provides the same degradation. The ozonation treatment achieved complete degradation at 30 minutes of reaction time. On the other hand, it was observed that the degradation was faster by adding H2O2 (H2O2/O3 molar ratio = 0.5). In this case, total degradation was observed after 20 minutes.

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