[Pectic polysaccharides in the stem calli of the rowan tree Sorbus aucuparia L].

The water-soluble polysaccharide fractions SAcI and SAclI were isolated from rowan tree stem calli. The SAcI fraction was shown to contain compounds belonging to the arabinogalactan II group. The SAcII fraction, termed sorban, was found to contain pectic polysaccharides that make up the protopectin complex of the cell wall callusand that had a high content of galacturonic acid residues together with neutral sugars characteristic of rhamnogalacturonan I (RG-I) polysaccharides. Using methylation assays, some structural features of the ramified region of sorban were elucidated. The backbone of sorban was found to consist of 1,4-α-D-galacto-pyranosyluronic acid residues. The neutral sugars are represented by 1,6-linked galactopyranose and 1,5-linked arabinofuranose residues as the primary constituents, as well as 1,6-linked mannopyranose and 1,4-linked glucopyranose and xylopyranose residues. Callus growth was shown to be accompanied by nearly constant quantities of galacturonic acid and neutral sugar residues in sorban (fraction SAcII) from the rowan stem callus.

[Effect of the rol genes from Agrobacterium rhizogenes on the content and structure of pectic substances and glycanase activity in Rubia cordifolia transgenic cell cultures].

The expression of the rolB gene was found to increase the pectic yield in Rubia cordifolia cells, while the rolC gene inhibited the pectin production, which correlated with its expression level. The expression of the rolA, rolB, and rolC genes led to an increase in the content of arabinogalactan (AG) in cells. The increase in the expression of the rolB and rolC genes resulted in a more significant reduction in the content of arabinose residues in pectin, which was accompanied by an increased activity of alpha-L-arabinofuranosidase in cells. Moreover, the amount of galactose residues in pectin increased with the enhancement of the rolB expression due to a decrease in the activity of beta-galactosidase in cells. The content of galacturonic acid residues in pectin from transgenic cultures increased in the following order: rolC < rolB < rolA. The amount of arabinose residues in AG decreased independently of the gene type. The amount of arabinose residues in AG was found to be considerably reduced when the rolB expression level was increased.

[Pectin substances of the callus culture of Silene vulgaris (M.) G].

Pectin-protein fraction SVC was isolated from the callus culture of the bladder campion (Silene vulgaris). The main components in it were residues of D-galacturonic acid, galactose, arabinose, rhamnose, and protein. Using ion-exchange chromatography, ultrafiltration, and acid and enzymatic hydrolysis, it was shown that SVC contained a mixture of molecules of linear pectin, branched pectin polysaccharide, and pectin-protein polymer. A fragment of the linear chain of galacturonan amounted to more than half of the entire carbohydrate silenan chain. The branched area of the macromolecule is represented by rhamnogalacturonan I. The pectin-protein polymer consisted mainly of protein and weakly branched pectin fragments with molecular mass of more than 300 kDa.

[The effects of ultraviolet irradiation upon structure and antioxidant activity of silenan from bladder campion callus].

Effects of UV-B (280-315 nm) and UV-C (254 nm) at various doses upon callus of bladder campion (Silene vulgaris (M.) G. were studied. It was revealed that UV irradiation results in the decrease in arabinose and galactose residues in the silenan--the pectin fraction isolated from callus. The silenan possesses antioxidant activity (AOA) as assessed by the reaction with a stable radical. At the irradiation of callus by UV, the AOA of the silenan and the relative content of phenolic compounds in it increased; the highest increase was observed after the irradiation of callus by UV-B. Positive correlation between the AOA of the pectin fraction and an increase in phenolic compounds was revealed. This evidences that the AOA of the silenan relates to and is partially determined by phenolic compounds in its composition. The UV irradiation may be used as a tool to modify the structural features of the cell walls' polysaccharides in order to produce physiologically-active polysaccharides with desired properties.

[Current information about pectin substances].

This review concerns pectin substances, the most complex class of plant polysaccharides. For the most part, the data reported after 1998 are presented; the references to earlier works are made only in the historical aspect. New data on the structure of pectin substances, their physiological activity, their role in plants, and their valuable physical properties are surveyed.

[Production of polysaccharides by callus cultures of common duckweed].

Callus lines of common duckweed produced acid arabinogalactan and pectin in an amount varying from 1 to 3% of dry weight. The arabinogalactan specimens from the cell lines studied displayed a similar monosaccharide composition. The duckweed callus lines whose arabinogalactans contained apiose residues (1-2%) were found. All pectin specimens had a similar qualitative monosaccharide composition but differed in the quantitative content of monosaccharide residues. The lines with high contents of galactose, arabinose, and apiose in pectin specimens were obtained. The total content of neutral monosaccharide residues in pectins varied from 26 to 50%.

[The effect of ultraviolet radiation on the growth and polysaccharide composition of a callus culture of Silene vulgaris].

Ultraviolet radiation (wavelength, 280-315 nm; power, 0.2-13.0 W/m2; exposure, 1 or 3 h) was shown to change the growth of campion callus and the polysaccharide (pectin and arabinogalactan) composition of cell walls. An increase in the concentration of polysaccharides and a decrease in the content of arabinose and galactose residues in pectin and arabinogalactan were noted. For the majority of calluses, growth indices, specific growth rate, and biomass productivity (per 11 medium) were almost the same as in nonirradiated control cells. Maximum values of the growth index and specific growth rate, determined for dry biomass, were observed at a low dose of irradiation (0.2 W/m2) and an exposure of 3 h. A considerable decrease in the content of arabinose and galactose in pectin was noted at high doses of irradiation (exposure, 3 h). Samples of arabinogalactan were characterized by variable arabinose to galactose ratios, which were in the range 1 : (3.4-8.3).

[Structural study of bergenan, a pectin from Bergenia crassifolia].

A pectin polysaccharide named bergenan was isolated from the freshly collected leaves of the leather bergenia Bergenia crassifolia by extraction with an aqueous solution of ammonium oxalate. The main component of its carbohydrate chain was shown to be the residues of D-galacturonic acid (about 80%). In addition, the polysaccharide contains residues of galactose, arabinose, and rhamnose; their total content is less than 15%. It was shown that the bergenan samples from bergenia leaves collected at different vegetation periods (from July to September) do not substantially differ either in monosaccharide composition or in the viscosity of aqueous solutions they form. The results of enzymatic hydrolysis by alpha-1,4-galacturonase (pectinase), partial acidic hydrolysis, NMR spectroscopy, and methylation with subsequent analysis of the results by GC-MS indicate that the bergenan macromolecule contains the regions of a linear alpha--1,4-D-galactopyranosyluronan and rhamnogalacturonan-I (RG-1). Galacturonan responds for a greater part of the macromolecule. A considerable amount of its constituent galacturonic acid residues are present as methyl esters. The side chains in RG-I are attached to the rhamnopyranose residues of the main carbohydrate chain by 1,4-link and are composed of the residues of terminal arabinofuranose and galactopyranose, 1,5-linked (-arabinofuranose, and 1,4-and 1,6-linked beta-galactopyranose. The branching points of the side chains of the RG-I molecule are 3,4- and 3,6-di-O-substituted galactose residues.

[Inhibition of neutrophil adhesion by pectic galacturonans].

The inhibition of the adhesion of neutrophils to fibronectin by the fragments of the main galacturonan chain of the following pectins was demonstrated: comaruman from the marsh cinquefoil Comarum polustre, bergenan from the Siberian tea Bergenia crassifolia, lemnan from the duckweed Lemna minor, zosteran from the seagrass Zostera marina, and citrus pectin. The parent pectins, except for comaruman, did not affect the cell adhesion. Galacturonans prepared from the starting pectins by acidic hydrolysis were shown to reduce the neutrophil adhesion stimulated by phorbol 12-myristate 13-acetate (1.625 microM) and dithiothreitol (0.5 mM) at a concentration of 50-200 microg/ml. The presence of carbohydrate chains with molecular masses higher than 300, from 100 to 300, and from 50 to 100 kDa in the galacturonan fractions was proved by membrane ultrafiltration.

[Isolation and structural study of polysaccharides from campion Silene vulgaris]. / Vydelenie i issledovanie stroeniia polisakharidov iz smolevki obyknovennoi Silene vulgaris.

Silenan SV, a pectic polysaccharide, was isolated from the aerial part of Silene vulgaris (Moench) Garke (Oberna behen (L.) Ikonn.), widespread through the European North of Russia. The polysaccharide was found to contain residues of galacturonic acid (63%), arabinose, galactose, and rhamnose as the main constituents. The results of a partial acidic hydrolysis, pectinase digestion, and NMR studies of silenan SV indicated that its molecule contains a linear alpha-1,4-D-galacturonan backbone and ramified regions. The core of the ramified regions is composed of residues of alpha-1,4-D-galacturonic acid along with 2-substituted alpha-rhamnopyranose residues. The NMR data showed that the silenan SV side chains are composed of the blocks built from the terminal alpha-1,5-linked arabinofuranose and beta-1,4-linked galactopyranose residues; these most likely are the side chains of rhamnogalacturonan, characteristic of other pectic polysaccharides. The nonreducing ends of these side chains contain alpha-arabinofuranose residues.

[The isolation, preliminary study of structure and physiological activity of water-soluble polysaccharides from squeezed berries of Snowball tree Viburnum opulus]. / Vydelenie i predvaritel'noe issledovanie stroeniia i fiziologicheskoi aktivnosti vodorastvorimykh polisakharidov iz shrota iagod Kaliny obyknovennoi Viburnum opulus.

Water-soluble polysaccharide fractions VO1-VO4 were isolated from the squeezed berries of snowball tree (Viburnum opulus) by successive extraction with water at various temperatures and pH and with aqueous solutions of ammonium oxalate. These fractions were purified by ion-exchange chromatography on DEAE cellulose, and the homogeneity of the purified polysaccharides was determined by gel filtration on Sephacryl S-500. Acidic polysaccharides close to pectins in their sugar composition were found in all the extracts (fractions VO1-1, VO2-1, VO3-2, and VO4-2). Residues of galacturonic acid, galactose, arabinose, and (to a lesser extent) rhamnose are their main constituents. Neutral polysaccharides composed mainly of galactose and mannose residues were additionally found in fractions extracted with acidified water (pH 4.0) and with aqueous ammonium oxalate solutions. Partial acidic hydrolysis and digestion with pectinase of acidic polysaccharides indicated that their carbohydrate backbone consists of alpha-1,4-linked residues of D-galacturonic acid. NMR spectra of acidic polysaccharides (fractions VO3-2 and VO3-3) confirmed this and demonstrated that their side oligosaccharide chains are composed of beta-1,4-linked galactopyranose residues and of terminal and 2,5- and 3,5-substituted residues of alpha-arabinofuranose at a Gal: Ara ratio of 3:1. Some polysaccharides from V. opulus were found to possess an immunostimulating activity: they enhance phagocytosis, in particular, the phagocytic index and the secretion of lysosomal enzymes with peritoneal macrophages. Calcium ions were found to be necessary for the appearance of the stimulating effect of acidic polysaccharides from V. opulus.

[Structure and physiological activity of lemnan, Lemna minor L. pectin]. / Strukturnoe issledovanie i fiziologicheskaia aktivnost' lemnana, pektina iz Lemna minor L..

A pectic polysaccharide, lemnan, was isolated from freshly collected duckweed Lemna minor L. Its sugar chain was shown to be mainly composed of the residues of D-galacturonic acid (64%), galactose, arabinose, xylose, and D-apiose, a branched chain sugar. The high content of D-apiose (25%) indicated that lemnan is an apiogalacturonan type pectin similar to zosteran, a pectic polysaccharide from a sea phanerogam of the Zosteraceae family. The results of partial acidic hydrolysis, pectinase digestion, and NMR studies of lemnan demonstrated that its macromolecule contains regions of the linear alpha-1,4-D-galacturonan and branched apiogalacturonan. The side chains of apiogalacturonan were found to be formed of single and 1,5-linked residues of D-apiofuranose attached to 2- and 3-positions of the D-galacturonic acid residues of the apiogalacturonan backbone. Lemnan was shown to exhibit an immunomodulatory effect by activating the system of phagocytosis.

[The immunomodulating action of mytilan in an experimental influenza infection]. / Immunomoduliruiushchee deistvie mitalana pri éksperimental'noi grippoznoi infektsii.

The materials characterizing the immunomodulating activity of mytilan, a bioglycane from an industrial object of Japanese sea, Crenomytilus grayanus, in experimental influenza infection are presented. The preparation protected up to 60% of mice intranasally inoculated with influenza virus, and significantly inhibited influenza virus reproduction. It induced interferon (possibly gamma IF) synthesis in low titres. The immunomodulating effect of mytilan consisted in stimulation of specific antibody genesis, enhancement of chemotaxis, increasing oxidation-reduction activity, enhancement of expression of Fc gamma-receptors by splenocytes and macrophages, enhancement of antibody-dependent spleen cell cytotoxicity, increased activity of natural killer cells, as well as increased complementary activity of blood serum and enhanced expression of C3 receptors by mouse spleen cells.

[Phagocytosis-stimulating effect of polysaccharides isolated from ginseng tissue culture]. / Fagotsitozstimuliruiushchee deistvie polisakharidov, vydelennykh iz ku'ltury tkani zhe'nshenia.

Materials characterizing immunostimulating activity of a polysaccharide fraction isolated from two lines of the ginseng tissue culture are presented. It was shown that under the drug action, the effector functions of polymorphonuclear leukocytes and macrophages activated.