Cleavage of dioxane lignin of the cotton plant with thioacetic acid

Summary 1. It has been established that the dioxane lignin of mature cotton-plant stems is cleaved by thioacetic acid. About 3/4 of the bonds in the lignin are alkyl-aryl ether bonds and only 1/4 are C-C bonds.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 505–507, July–August, 1978.     

A study of the structure of lignins of healthy and wilt-affected cotton plants of the variety Tashkent-1

Continuing a study of the dioxiane lignins of healthy and wilt-affected cotton plants of variety Tashkent-1 (DLCT) according to vegetation period, we have performed nitrobenzene oxidation and cleavage with sodium in liquid ammonia of the natural and isolated dioxane lignins. It has been established that in the wilt-affected samples of cotton-plant stems the amount of guaiacyl and syringyl structural units increases.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 392–396, May–June, 1979.     

Investigation of the dioxane lignin of the cotton plant

Summary 1. The dioxane lignins of the stems of cotton plants in the early vegetation period, DLA-I, and in the flowering period, DLA-II, have been investigated. Their developed semiempirical formulas have been established by elementary and functional-group analyses.2. The amounts of catechol structural units in cotton-plant dioxane lignins have been determined for the first time.3. The molecular-weight distribution of the dioxane lignins has been studied and it has been shown that they have high molecular weights (22,000–23,500).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 80–83, January–February, 1976.     

Metabolites of the pathogenic fungus Verticillium dahliae VII. The phytotoxic pigment PKZh-1 from the culture liquid

Summary The phytotoxic pigment PKZh-1 that causes the characteristic symptoms of wilt in tests on cotton-plant shoots in a concentration of 100–150 µg/ml, has been isolated from the culture liquid of the fungusVerticillium dahliae Kleb.On the basis of qualitative reaction, spectral characteristics, and a study of hydrolysis products, PKZh-1 has been assigned to the peptide group. A red substance identified as 3,6,8-trihydroxy-1,4-naphthaquinone has been isolated from an acid hydrolyzate of PKZh-1.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 690–693, September–October, 1977.     

Lignin of the fine-fibered cotton plant of variety S-6030 affected by fusarial wilt. II

A comparative study of the products of cleavage by sodium in liquid ammonia of the dioxane lignins (DLAs) from healthy and fusarial-wilt-affected stems of the fine-fibered cotton plant of variety S-6030 and a study of the PMR spectra of both lignins has shown that the DLA from the healthy stems is more highly condensed than the DLA of the stems affected by wilt. The main structures of DNA wilt are of the guaiacyl type. In the DLA from the affected stems, the amount of p-coumaryl structures had increased, which confirms the demethylating action of fusarial wilt on cotton-plant lignin.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 364–366, May–June, 1986.     

Structure of a glucuronoxylan from alfalfa stems

The results are given of a study of the primary structure of a xylan from the stems of alfalfa,Medicago sativa. The structural features of the xylan were established by comparing the results of chemical and physical methods of investigation: methylation, periodate oxidation, acid and enzymatic hydrolysis, oxidation with CrO₃, and IR and NMR spectroscopy. It was found that the macromolecule is based on a linear chain constructed of D-xylopyranose residues, and side chains constructed of 4-O-methylglucuronic acid residues are attached to the second carbon atoms.M. V. Lomonosov Odessa Technological Institute of the Food Industry. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 324–327, May–June, 1989.     

Study of the fractional composition of the dioxane lignin from the cotton plant

Summary 1. The dioxane lignin of ripe cotton-plant stems has been separated into six fractions of different molecular weights which were fairly homogeneous and differed considerably in their molecular weights.2. It follows from the semiempirical formulas that in all the fractions guaiacyl structural units predominated. The chemical nonidentity of the fractions is shown by the different amounts of functional groups in the phenylpropane structural units and by the relative optical densities of the main bands in the IR spectra of the fractions.3. The low-molecular-weight fraction differed markedly from the others by a higher content of carbohydrates bound to the lignin and by a greater degree of oxidation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 69–74, January–February, 1979.     

Reductive cleavage by sodium in liquid ammonia of the lignin of cotton-plant stems

Summary 1. The reductive degradation by metallic sodium and liquid ammonia of the lignin of green cotton-plant stems has confirmed the presence in them of three types of structural units: syringyl, guaiacyl, and p-hydroxycoumaryl.2. The preliminary sonication of the plant with ultrasound leads to a decrease in the amount of products containing methoxy groups in the aromatic nucleus, particularly syringyl structures.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 643–646, September–October, 1976.     

Influence of additions of anthraquinone on the alkaline hydrolysis of cotton-plant lignin

The action of catalytic amounts of anthraquinone on the alkaline hydrolysis of the stems and dioxane lignin of the cotton plant of the ssp.mexicanium has been investigated. It has been established that this leads to a substantial increase in the yield of low-molecular-weight hydrolysis products. Analysis of the monomeric fractions of the hydrolysis products by the GLC method has shown the presence in them of large amounts of substances with a p-coumaryl structure. This, and also the low level of syringyl derivatives, may be caused by the demethoxylation of the lignin under the conditions described.Institute of the Chemistry of Plant Substances, Academy of Sciences of the USSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 391–395, May–June, 1985.     

Cellulose crystallinity and ordering of hemicelluloses in pine and birch pulps as revealed by solid-state NMR spectroscopic methods

Solid-state ¹³C NMR spectroscopy was used to determine the degree of cellulose crystallinity (CrI) in kraft, flow-through kraft and polysulphide–anthraquinone (PS–AQ) pulps of pine and birch containing various amounts of hemicelluloses. The applicability of acid hydrolysis and the purely spectroscopic proton spin-relaxation based spectral edition (PSRE) method to remove the interfering hemicellulose signals prior to the determination of CrI were also compared. For softwood pulps, the spectroscopic removal of hemicelluloses by PSRE was found to be more efficient than the removal of hemicelluloses by acid hydrolysis. In addition to that, the PSRE method also provides information on the associations between cellulose and hemicelluloses. On the basis of the incomplete removal of xylan from the cellulose subspectra by PSRE, the deposition of xylan on cellulose fibrils and therefore an ordered ultrastructure of xylan in birch pulps was suggested. The ordered structure of xylan in birch pulps was also supported by the observed change of xylan conformation after regeneration. Similarly, glucomannan in pine pulps may have an ordered structure. According to the ¹³C CPMAS measurements conducted after acid hydrolysis, the degree of cellulose crystallinity was found to be slightly lower in birch pulps than in the pine pulps. Any significant differences in cellulose crystallinity were not found between the pulps obtained by the various pulping methods. Only in pine PS–AQ pulp, the degree of cellulose crystallinity may be slightly lower than in the kraft pulps containing less hemicelluloses.     

Isolation and characterization of phytokinin-binding proteins from the cotton plant

A highly purified site of a cytokinin-binding protein with a K_D value for³H-BAP of 4.3 nM has been isolated from cotton-plant seedlings by the methods of biospecific and hydrophobic chromatography. According to the results of electrophoretic analysis under denaturing conditions its molecular mass is 43 kDa.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbekestan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 702–706, November–December, 1992.     

Separation of the lignocellulose of nonwoody plants into its main components and study of their properties

It has been shown that as a result of preliminary acid hydrolysis followed by alkaline treatment there is a separation of the lignocellulose of nonwoody plants (cotton plant stems, kenaf tow) into the structural substances of the cell wall. The nature of the separated components has been established as cellulose and a lignocarbohydrate mixture.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 118–122, January–February, 1998.     

The structure of the xylan from cotton-plant stems

Summary The results of a study of the products of the hydrolysis and oxidative cleavage according to Barry of cotton-plant-stem xylan has shown that its main chain consists of 14--L-anhydroxylopyranose units. Each elementary link of the xylan contains 6–7 xylopyranose units and has two side chains formed by residues of D-glucose and D-glucuronic acid, which are attached in position 2 or 3 of the xylose units of the main chain.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 305–308, May–June, 1973.     

Study of the lignin of cotton plants of the variety AN Bayaut-2. I

The dioxane lignin has been isolated from ripe stems of a cotton plant of the variety AN Bayaut-2. Its developed empirical formula has been derived, its UV, IR, and PMR spectra have been recorded, and its molecular weight has been determined. It has been shown that the dioxane lignins of the stems of cotton plants of different varieties differ in chemical structure.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 101–104, January–February, 1986.     

Detection and separation of two forms of cotton-plant pyrophosphatase

Two pyrophosphatase isoenzymes with identical molecular weights but differing in the pH optima of their action and also in their senstivity to some bivalent metal ions have been isolated from extracts of the cotyledons of three-day cotton-plant shoots by gel filtration and ion-exchange chromatography.V. I. Lenin Tashkent State University. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 375–378, May–June, 1985.     

Structure of a glucuronoxylan of the stems ofSymphytum asperum

The results are given of an investigation of the structure of a glucuronoxylan of the stems ofSymphytum asperum Ler. The xylan was isolated by alkaline extraction and was purified by reprecipitation via the copper complex. The polysaccharide was homogeneous according to the results of gel filtration and electrophoresis. It was shown by hydrolysis, periodate oxidation, methylation, oxidation with chromium trioxide and IR and¹³C NMR spectroscopy that the macromolecules were based on a -(14)-polyxyloside chain having side chains at the second carbon atoms in the form of 4-O-Me-D-glucuronic acid. To each side chain there were not less than 12 xylose residues.M. V. Lomonosov Technological Institute of the Food Industry, Odessa. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 478–481, July–August, 1985.     

Alkaline hydrolysis of the natural lignin of cottonplant stems in the presence of anthraquinone

The study of a three-stage alkaline hydrolysis of the natural lignin of cottonplant stems has shown that the bulk of the lignin undergoes fragmentation during stage I. The addition of anthraquinone leads to an appreciable increase in the yield of low-molecular-mass hydrolysis products.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 89 14 75. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 743–748, September–October, 1996. Original article submitted March 1, 1993.     

Aminomethylation of dioxane lignins of healthy and wilt-diseased cotton plants of the variety Tashkent-1

The products of the aminomethylation of dioxane lignins of healthy and wilt-diseased plants of variety Tashkent-1 according to the vegetation periods (ADLKhT-1-VII) have been studied. It has been established that the dioxane lignins of the wilt-diseased cotton-plant stems are less condensed. Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 704–706, September–October, 1980.     

Kinetics of the formation of a complex of the palladium ion with 1,8-dihydroxy-2-(2-pyrazoline-5-azo) naphthalene-3,6-disulfonic acid

The kinetics of the complex-formation of the palladium ion with 1,8-dihydroxy-2-(2-pyrazolin-5-azo)naphthalene-3,6-disulfonic acid has been studied in aqueous solution (pH 0–5). It has been shown that the rate of the reaction is a maximum at pH 2.8 and falls at pH > 2.9 because of the hydrolysis of the palladium ions and at pH < 2.9 as a consequence of the protonation of the reagent molecule.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 21, No. 5, pp. 611–613, September–October, 1985.     

Influence of defoliating agents on the level of some secondary metabolites in cotton-plant leaves

The change in the composition of the secondary metabolites (SMs) of cotton-plant leaves under the influence of two modifications of defoliating agents in the period of leaf fall has been studied. It has been shown that, in contrast to the dynamics of the SMs in genetic deciduous lines, up to the period of leaf-fall the amount of free sterols in the petioles decreases, while in the leaf blades it remains unchanged. In experiments with cotyledons, the opposite effect was observed. In all cases, the amount of polyprenols decreased substantially.Institute of Chemistry of Plant Substances, Uzbekistan Republic Academy of Sciences, Tashkent. Institute of Experimental Plant Biology, Uzbekistan Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 67–71, January–February, 1992.