scholarly journals Structural studies of the carbohydrate moieties of lectins from potato (Solanum tuberosum) tubers and thorn-apple (Datura stramonium) seeds

1982 ◽  
Vol 201 (1) ◽  
pp. 199-208 ◽  
Author(s):  
David Ashford ◽  
Nila N. Desai ◽  
Anthony K. Allen ◽  
Albert Neuberger ◽  
Malcolm A. O'Neill ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Chemical Ionization ◽  
Optical Rotation ◽  
Gel Filtration ◽  
Datura Stramonium ◽  
Plant Cell Walls ◽  
Methylation Analysis ◽  
Thorn Apple ◽  
Optical Rotations ◽  
Potato Lectin

1. Methylation analysis of potato (Solanum tuberosum) lectin and thorn-apple (Datura stramonium) lectin confirmed previous conclusions that both glycoproteins contained high proportions of l-arabinofuranosides and lesser amounts of d-galactopyranosides. The arabinofuranosides are present in both lectins as short unbranched chains containing 1→2- and 1→3-linkages, which are known to be linked to hydroxyproline. Galactopyranosides are present as monosaccharides, which are known to be attached to serine, in potato lectin and as both the monosaccharide and the 1→3-linked disaccharide in Datura lectin. 2. Alkaline digestion of potato lectin and subsequent separation of the components by gel filtration led to the isolation of four fractions corresponding to the mono-, di-, tri- and tetra-arabinosides of hydroxyproline. The latter two fractions accounted for over 70% of the total hydroxyproline. 3. Methylation analysis was used to show that the triarabinoside contained only 1→2-linkages between sugars, but that the tetra-arabinoside contained both 1→2- and 1→3-linkages. Direct-insertion mass spectrometry of these compounds using electron impact and chemical ionization, in a comparison with other known structural patterns, was used to determine the sequences of the sugars, which were Araƒ1→2Araƒ1→2Araƒ1→Hyp and Araƒ1→3Araƒ1→2Araƒ1→2Araƒ 1→Hyp. 4. On the basis of optical rotation it had previously been suggested [Allen, Desai, Neuberger & Creeth (1978) Biochem. J.171, 665–674] that all the arabinose of potato lectin was present as the β-l-furanoside. However, measurement of the optical rotations of the hydroxyprolyl arabinosides showed that whereas the diarabinoside had a molar rotation ([m]) value close to that predicted, the triarabinoside was more dextrorotatory and the tetra-arabinoside was less dextrorotatory than expected. Possible explanations for these findings are that, although the di- and tri-arabinosides contain exclusively β-arabinofuranosides, in the tri-arabinoside, interactions between pentose units lead to an enhanced positive rotation. The tetra-arabinoside, however, is proposed to contain a single α-arabinofuranoside residue, which is responsible for the lower than expected positive rotation. The observed rotation of the tetra-arabinoside was found to be close to the theoretical value predicted on that basis. Furthermore, the action of a specific α-arabinofuranosidase on the tetrasaccharide was to remove a single arabinose residue, presumably the terminal non-reducing sugar, and to produce a product that was indistinguishable on electrophoresis from the triarabinoside. Changes in rotation were compatible with this assumption. 5. It is concluded that the structures of the hydroxyprolyl tri- and tetra-arabinosides of potato lectin are: βAraƒ1→2βAraƒ1→2βAraƒ1→Hyp and αAraƒ1→3βAraƒ1→2βAraƒ 1→2βAraƒ1→Hyp. These are identical with compounds that have been isolated from the insoluble hydroxyproline-rich glycoproteins of plant cell walls.

scholarly journals Some properties of the lectin from Datura stramonium (thorn-apple) and the nature of its glycoprotein linkages

1981 ◽  
Vol 197 (2) ◽  
pp. 345-353 ◽  
Author(s):  
Nila N. Desai ◽  
Anthony K. Allen ◽  
Albert Neuberger
Keyword(s):  
Amino Acids ◽  
Polypeptide Chain ◽  
Gel Filtration ◽  
Datura Stramonium ◽  
Inhibitory Effect ◽  
Plant Cell Walls ◽  
Thorn Apple ◽  
A Subunit ◽  
Sepharose 4B ◽  
Derivatives Of

The lectin from Datura stramonium (thorn-apple; Solanaceae) has been purified by affinity chromatography and shown to be a glycoprotein containing about 40% (w/w) of carbohydrate. The most abundant amino acids are hydroxyproline, cystine, glycine and serine. Results obtained by gel filtration in 6m-guanidinium chloride on Sepharose 4B suggest that it has a subunit mol.wt. of about 30000 and that it probably associates into dimers. The lectin is inhibited specifically by chitin oligosaccharides and bacterial-cell-wall oligosaccharides, but only weakly by N-acetylglucosamine. Glycopeptides from soya-bean (Glycine max) lectin and fetuin are also strong inhibitors of Datura lectin, indicating that it interacts with internal N-acetylglucosamine residues. Its specificity is similar to, but not identical with, that of potato (Solanum tuberosum) lectin. After prolonged proteolytic digestion of reduced and S-carboxymethylated or S-aminoethylated derivatives of the lectin, glycopeptides of mol.wt. of about 18000 were isolated. The glycopeptides contained all the carbohydrate and hydroxyproline of the original glycoprotein, and lesser amounts of serine, S-carboxymethylcysteine and other amino acids. The arabinose residues of the glycoprotein are present as β-l-arabinofuranosides linked to the polypeptide chain through the hydroxyproline residues, and can be removed by mild acid treatment; the ratio of arabinose to hydroxyproline is 3.4:1. Some of the serine residues of the polypeptide chain are substituted with one or two α-galactopyranoside residues, most of which can be removed by the action of α-galactosidase. The galactose residues are more easily removed from the acid-treated glycopeptide (from which arabinose has been removed) than from the complete glycopeptide, indicating a steric hindrance of the galactosidase action by the adjacent chains of arabinosides. There is a slow release of galactose residues by a process of β-elimination in 0.5m-NaOH (pH13.7) from the complete glycopeptide, and a fairly rapid release of galactose by this process from the acid-treated glycopeptide, which lacks arabinose. This is probably due to the inhibitory effect of the negative charge on the adjacent arabinofuranoside residues. The similarities and differences between the lectins from Datura and potato are discussed, as are their structural resemblance to glycopeptides that have been isolated from plant cell walls.

Allelopathic potential of Datura stramonium L. (Thorn-apple)

Weed Research ◽  
1981 ◽  
Vol 21 (3-4) ◽  
pp. 165-170 ◽  
Author(s):  
J. V. LOVETT ◽  
JUDY LEVITT ◽  
A. M. DUFFIELD ◽  
N.G. SMITH
Keyword(s):  
Datura Stramonium ◽  
Allelopathic Potential ◽  
Thorn Apple

scholarly journals A glucan from active dry baker’s yeast (Saccharomyces cerevisiae): A chemical and enzymatic investigation of the structure

2003 ◽  
Vol 68 (11) ◽  
pp. 805-809 ◽  
Author(s):  
Dragan Zlatkovic ◽  
Dragica Jakovljevic ◽  
Djordje Zekovic ◽  
Miroslav Vrvic
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Optical Rotation ◽  
Linear Chain ◽  
Periodate Oxidation ◽  
Methylation Analysis ◽  
Yeast Saccharomyces Cerevisiae ◽  
New Approach ◽  
Main Structural Feature ◽  
Or Groups

The structure of a polysaccharide consisting of D-glucose isolated from the cell-wall of active dry baker?s yeast (Saccharomyces cerevisiae) was investigated by using methylation analysis, periodate oxidation, mass spectrometry, NMR spectroscopy, and enzymic hydrolysis, as a new approach in determination of structures. The main structural feature of the polysaccharide deduced on the basis of the obtained results is a linear chain of (1?3)-linked ?-D-glucopyranoses, a part of which is substituted through the positions O-6. The side units or groups are either a single D-glucopyranose or (1?3)-?-oligoglucosides, linked to the main chaing through (1?6)-glucosidic linkages. The low optical rotation as well as the 13C-NMR and FTIR spectra suggest that the glycosidic linkages are in the ?-D-configuration.

Identification of d- or di-∝-Tocopherol in Pharmaceuticals, Food Supplements, or Feed Supplements: A Collaborative Study

1975 ◽  
Vol 58 (3) ◽  
pp. 585-594
Author(s):  
Stanley R Ames ◽  
Emma-Jane E Drury
Keyword(s):  
Vitamin E ◽  
Oxidation Product ◽  
Optical Rotation ◽  
Collaborative Study ◽  
Food Supplements ◽  
Tocopheryl Acetate ◽  
Specific Optical Rotation ◽  
Feed Supplements ◽  
Before And After ◽  
Optical Rotations

Abstract A collaborative study was conducted to evaluate a method for identifying d- or dl-∝-tocopherol in pharmaceuticals, food supplements, or feed supplements. The sample is extracted and saponified, the extraneous color is removed by chromatography, and the sample is assayed for vitamin E. Optical rotations are determined before and after formation of the ferricyanide oxidation product. The specific optical rotation of the oxidation product is negligible for the dJ-form and +25.5° for the d-form. Statistical analysis of the data reported by 8 collaborators for the standard d-∝-tocopheryl acetate and for 6 unknown samples indicates a significant interaction between laboratories and samples. The mean coefficients of variation among laboratories for the determinations of the corrected specific optical rotation of the standard and the rotation ratio for the unknown samples containing d-∝-tocopherol were 11.7 and 21.6%, respectively, for all laboratories and 5.8 and 11.8%, respectively, for experienced laboratories. This identification test for vitamin E is acceptable for determining the form of vitamin E as either d or dl, but is not acceptable for accurately determining mixtures of the 2 forms. The method has been adopted as official first action for the identification of d- or dl-∝-tocopherol.

scholarly journals Studies of the polysaccharide fraction from the lipopolysaccharide of Pseudomonas alcaligenes

1974 ◽  
Vol 139 (3) ◽  
pp. 633-643 ◽  
Author(s):  
James A. Lomax ◽  
George W. Gray ◽  
Stephen G. Wilkinson
Keyword(s):  
Gel Filtration ◽  
Periodate Oxidation ◽  
Side Chain ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Mild Acid Hydrolysis ◽  
Pseudomonas Alcaligenes ◽  
Crude Polysaccharide ◽  
Hydrolysis Of ◽  
Mild Acid

Studies of the lipopolysaccharide of Pseudomonas alcaligenes strain BR 1/2 were extended to the polysaccharide moiety. The crude polysaccharide, obtained by mild acid hydrolysis of the lipopolysaccharide, was fractionated by gel filtration. The major fraction was the phosphorylated polysaccharide, for which the approximate proportions of residues were; glucose (2), rhamnose (0.7), heptose (2–3), galactosamine (1), alanine (1), 3-deoxy-2-octulonic acid (1), phosphorus (5–6). The heptose was l-glycero-d-manno-heptose. The minor fractions from gel filtration contained free 3-deoxy-2-octulonic acid, Pi and PPi. The purified polysaccharide was studied by periodate oxidation, methylation analysis, partial hydrolysis, and dephosphorylation. All the rhamnose and part of the glucose and heptose occur as non-reducing terminal residues. Other glucose residues are 3-substituted, and most heptose residues are esterified with condensed phosphate residues, possibly in the C-4 position. Free heptose and a heptosylglucose were isolated from a partial hydrolysate of the polysaccharide. The location of galactosamine in the polysaccharide was not established, but either the C-3 or C-4 position appears to be substituted and a linkage to alanine was indicated. In its composition, the polysaccharide from Ps. alcaligenes resembles core polysaccharides from other pseudomonads: no possible side-chain polysaccharide was detected.

scholarly journals THE INTERRELATION OF THE SURVIVING HEART AND PANCREAS OF THE DOG IN SUGAR METABOLISM

1917 ◽  
Vol 26 (5) ◽  
pp. 721-744 ◽  
Author(s):  
Admont H. Clark
Keyword(s):  
Optical Rotation ◽  
Reducing Power ◽  
Sugar Metabolism ◽  
Weak Acid ◽  
Perfused Pancreas ◽  
Melting Points ◽  
Optical Rotations ◽  
Normal Utilization ◽  
Hydrolysis Of ◽  
Reducing Properties

When the pancreas of a dog is perfused aseptically with a Locke's solution containing dextrose in physiological concentrations, the optical rotation of the perfusate is diminished, but its reducing power is unaltered. This change also occurs if dextrose is added to a sugarfree pancreatic perfusate and the mixture incubated. These perfusates yield osazones with lower melting points than glucosazone, but when the perfusates are hydrolyzed with weak acid their optical, rotations and the melting points of their osazones are increased. These changes do not occur with levulose, or with an extract of the pancreas and dextrose. When the heart, spleen, or kidneys are perfused with dextrose solutions hydrolysis of the perfusates does not increase their optical rotation or power of reduction. When a pancreatic perfusate containing dextrose is circulated through a living heart not only do the above changes take place but, in addition, the reducing properties of the perfusate are altered. Hydrolysis of such a perfusate increases its reducing power, its optical rotation, and the melting point of its osazone. A heart does not cause this effect either alone or when perfused together with the spleen or kidneys. Levulose perfused through the heart and pancreas is unchanged. These phenomena are believed to be due to an enzyme or enzymes obtained from the perfused pancreas. The changes in optical rotation, in reduction, and in the osazones are accounted for by different degrees of dextrose condensation. While the living heart can destroy both dextrose and levulose to some extent, the experimental results suggest that the enzyme or enzymes derived from the perfused pancreas have a specific action on dextrose and are responsible for certain essential steps by which dextrose is prepared for normal utilization.

Acidic exopolysaccharide from Penicillium allahabadense

1984 ◽  
Vol 30 (9) ◽  
pp. 1157-1162 ◽  
Author(s):  
P. Rupérez ◽  
B. Gomez-Miranda ◽  
J. A. Leal
Keyword(s):  
Liquid Medium ◽  
Infrared Spectra ◽  
Optical Rotation ◽  
Extracellular Polysaccharide ◽  
Acid Form ◽  
Equivalent Weight ◽  
Methylation Analysis ◽  
Polysaccharide Fraction ◽  
Main Component ◽  
Ethanol Fraction

Penicillium allahabadense grown statically in liquid medium formed an extracellular polysaccharide which was collected by precipitation with ethanol (fraction A). The mycelium mat retained a considerable amount of polysaccharide extractable with water, which did not precipitate with ethanol but precipitated with FeCl3 (fraction B). Both fractions were formed mainly by glucose and malonic acid. Their optical rotation values and infrared spectra indicated β configuration. From fraction A was obtained the polysaccharide in the acid form (fraction C), whose equivalent weight is 425, and the demalonylated polysaccharide (fraction D). The main linkage type among glucose residues in the demalonylated polysaccharide, determined after Smith degradation, was 1 → 6. The main component obtained by methylation analysis was 2,3,4-tri-O-methyl-glucitol.

scholarly journals Molecular cohesion in plant cell walls. Methylation analysis of pectic polysaccharides from the cotyledons of white mustard

1969 ◽  
Vol 115 (3) ◽  
pp. 431-439 ◽  
Author(s):  
D. A. Rees ◽  
N. J. Wight
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Uronic Acid ◽  
Structural Elements ◽  
Plant Cell Walls ◽  
White Mustard ◽  
Methylation Analysis ◽  
Structural Units ◽  
Pectic Polysaccharides ◽  
Derivatives Of

Methylation analysis was used to characterize the pectic polysaccharides from mustard cotyledons, a tissue with potential for rapid biological change involving the walls. The methylated sugars were identified by g.l.c. and paper chromatography after conversion of uronic acid derivatives into [3H]hexoses, and confirmed by the formation of crystalline derivatives of most of the main products, which were: 2,3-di-O-methyl-d-[6−3H]galactose, 2-O-methyl-d-[6−3H]galactose, 3,4-di-O-methylrhamnose, 3-O-methylrhamnose, 2,3,5-tri-O-methyl-l-arabinose, 2,3-di-O-methyl-l-arabinose, 2-O-methyl-l-arabinose, 2,3,4-tri-O-methyl-d-xylose and 2,3,4,6-tetra-O-methyl-d-galactose in the molar proportions 1·00:1·14:0·54:0·74:2·86:2·50:2·24:1·88:0·32. The structural units present are similar to those in wellknown polysaccharides from mature tissues, but their proportions are strikingly different. Uninterrupted and unbranched galacturonan segments can therefore contribute little cohesion to these walls, and it is suggested that this correlates with a function of the wall matrix to hydrate and permit readjustment, during germination, of structural elements or wall surfaces or both.

scholarly journals Effects of Sowing Date on Some Agronomic Characteristics and Alkaloid Content of Datura Stramonium in Semi-Arid Conditions

2016 ◽  
Vol 49 (1) ◽  
pp. 41-50
Author(s):  
S. Kizil ◽  
Ö. Tonçer
Keyword(s):  
Seed Yield ◽  
Total Alkaloid ◽  
Datura Stramonium ◽  
Sowing Date ◽  
Pharmaceutical Products ◽  
Alkaloid Content ◽  
Agronomic Characteristics ◽  
Thorn Apple ◽  
Total Alkaloid Content ◽  
Herb Yield

Abstract Alkaloids of diferent plant, including many Solanaceae species, constitute important natural sources for variety of pharmaceutical products. The amounts of various secondary plant products are strongly dependent on the growing conditions and agronomical applications such as planting date, fertilization, irrigation etc. The aim of this was to study the effects of sowing date on some agronomic characteristics and total alkaloid content of thorn apple (Datura stramonium), investigated in the environmental conditions from Dicle University, Agricultural Faculty, Field Crops Department experimental area, during 2010 and 2011 growing years. In the research, plant height, stem diameter, number of branches per plant, number of capsule per plant, capsule width, capsule length, 1000-seed weight, fresh herb yield, herba yield, seed yield and total alkaloid content were examined. At the end of the study, in the trial of thorn apple with sowing dates, according to two years mean, seed yield, fresh herb yield, dry herb yield and total alkaloid yield were changed between 335 kg ha−1 and 704 kg ha−1, 5933 and 20537 kg ha−1, 1613 kg ha−1 and 4800 kg ha−1, and 0.270% and 0.391%, respectively. The effect of sowing date was found significant on the investigated characteristics, when sowing delayed, agronomic characteristics were also decreased. The highest values related with seed yield, fresh and dry herbage of thorn apple were obtained sowing of 01 Apr. Moreover, thorn apple plant showed morphogenetic variation when compared leaf and seed alkaloid contents.

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