pectins and arabinogalactan

Arabinogalactans (AGs) are plant heteropolysaccharides with complex structures occasionally attached to proteins (AGPs). AGs in cell matrix of different parts of plant are freely available or chemically bound to pectin rhamnogalactan. Type I with predominantly β-d-(1 → 4)-galactan and type II with β-d-(1 → 3) and/or (1 → 6)-galactan structural backbones construct the two main groups of AGs. In the current review, the chemical structure of AGs is firstly discussed focusing on non-traditional plant sources and not including well known industrial gums. After that, processes for their extraction and purification are considered and finally their techno-functional and biological properties are highlighted. The role of AG structure and function on health advantages such as anti-tumor, antioxidant, anti-ulcer- anti-diabetic and other activites and also the immunomodulatory effects on in-vivo model systems are overviewed.

Topics: Galactans; Pectins

Complexation of known drugs with carbohydrate-containing plant metabolites is a promising way to synthesize new drugs that does not only save pharmacological properties of initial agent but also acquire a number of advantageous features such as increased water solubility, bioavailability and decreased toxicity. This review reports on the development and pharmacological evaluation of novel complexes of various well-known drugs with vegetable coplexation agents: glycyrrhizic acid, Stevia glycosides, gypsogenin tetraoside, pectin, xyloglucan, arabinogalactan. The aim of this review is to describe advantages of the new approach, suggested by authors, in the development of low toxic and high-performance drugs.

Topics: Carbohydrates; Diterpenes, Kaurane; Galactans; Glucans; Glucosides; Glycyrrhizic Acid; Pectins; Pharmaceutical Preparations; Plants, Medicinal; Xylans

The non-cellulosic polysaccharides present in cereals (2-8%) are mostly arabinoxylans, (1 --> 3),(1 --> 4)-beta -glucans, pectins and arabinogalactans. Of these, the arabinoxylans are known to absorb large amounts of water and influence significantly the water balance, rheological properties of dough, and the retrogradation of starch and bread quality. (1 --> 3),(1 --> 4)-beta -glucans are known as biological response modifiers (BMS) as they are believed to modulate the immune response. Cereal Pectins and arabinogalactans form a very small amount and do not contribute substantially to the functionality of noncellulosic polysaccharides. Detailed structural investigations on cereal hetero xylans using modern techniques were initiated in the 1990s and still pose a challenge to carbohydrate chemists because of their structural complexity. Nutritionally, they are classified under "unavailable carbohydrates" (dietary fiber) along with lignin and cellulose and are known to have beneficial effects in alleviating disease symptoms such as diabetes, atherosclerosis, and colon cancer. In this review isolation, purification, characterization, structural elucidation, functional, and nutritional attributes of cereal heteroxylans are covered with particular emphasis on recently characterized finger millet arabinoxylans.

Topics: Dietary Fiber; Edible Grain; Food Analysis; Food Technology; Galactans; Glucans; Humans; Nutritive Value; Pectins; Polysaccharides; Rheology; Spectroscopy, Near-Infrared; Structure-Activity Relationship; Xylans

Non-lignified fibre cells (named gelatinous fibres) are present in tension wood and the stems of fibre crops (such as flax and hemp). These cells develop a very thick S2 layer within the secondary cell wall, which is characterised by (1) cellulose microfibrils largely parallel to the longitudinal axis of the cell, and (2) a high proportion of galactose-containing polymers among the non-cellulosic polysaccharides. In this review, we focus on the role of these polymers in the assembly of gelatinous fibres of flax. At the different stages of fibre development, we analyse in detail data based on sugar composition, linkages of pectic polymers, and immunolocalisation of the beta-(1-->4)-galactans. These data indicate that high molecular-mass gelatinous galactans accumulate in specialised Golgi-derived vesicles during fibre cell-wall thickening. They consist of RG-I-like polymers with side chains of beta-(1-->4)-linked galactose. Most of them are short, but there are also long chains containing up to 28 galactosyl residues. At fibre maturity, two types of cross-linked galactans are identified, a C-L structure that resembles the part of soluble galactan with long side chains and a C-S structure with short chains. Different possibilities for soluble galactan to give rise to C-L and C-S are analysed. In addition, we discuss the prospect for the soluble galactan in preventing the newly formed cellulose chains from completing immediate crystallisation. This leads to a hypothesis that firstly the secretion of soluble galactans plays a role in the axial orientation of cellulose microfibrils, and secondly the remodelling and cross-linking of pectic galactans are linked to the dehydration and the assembly of S2 layer.

Topics: Cell Wall; Cellulose; Flax; Galactans; Galactose; Golgi Apparatus; Microfibrils; Pectins; Plant Stems; Proteoglycans; Solubility

This review presents recent data about cell wall involvement in plant embryogenesis. During plant development, the cell wall is subjected to precise regulation. During this process a bidirectional information exchange between the cell wall and the protoplast is observed. The cell wall also mediates in the cell-cell (apoplastic) and cell to cell (symplastic) information flow. Especially some products derived from the hydrolysis of specific cell wall compounds can act as short distance signal transduction molecules during the development. Oligosaccharins are a group of such products. Their activity and sources focused the researchers' attention on the biochemical composition of the cell wall and the activity of some cell wall enzymes. The dramatic influence on the embryo body shape has also the cell wall synthesis machinery, including vesicular secretion pathways. Moreover, the interplay between the turgor pressure and counteracting cell walls and neighbouring cells (in higher organisms) creates the specific mechanical forces influencing the development of the whole plant. We conclude that discovering factors which can influence cell wall physiology and architecture is crucial for a better understanding of plant embryogenesis. In this review we summarize some recent experimental data reporting plant cell wall involvement in embryogenesis, putting special emphasis on somatic embryogenesis.

Topics: Cell Wall; Chitinases; Galactans; Glycoproteins; Glycosyltransferases; Pectins; Peroxidases; Plants

Topics: Cell Wall; Cellulose; Chemical Phenomena; Chemistry; Galactans; Glucans; Glycoproteins; Models, Molecular; Pectins; Phytoalexins; Plant Cells; Plant Extracts; Plant Growth Regulators; Plant Physiological Phenomena; Plant Proteins; Plants; Polysaccharides; Protease Inhibitors; Sesquiterpenes; Terpenes; Xylans

The aim of this study was to prepare conjugates of casein (CA) with pectin (CP) or arabinogalactan (AG) by the Maillard reaction (wet-heating) and to investigate the effects of CP or AG on the structural and functional properties of casein. The results indicated that the highest grafting degree of CA with CP or AG was observed at 90 °C for 1.5 h or 1 h, respectively. Secondary structure showed that grafting with CP or AG reduced the α-helix level and increased the random coil level of CA. Glycosylation treatment of CA-CP and CA-AG exhibited lower surface hydrophobicity and higher absolute ζ-potential values, further significantly improving the functional properties of CA (e.g., solubility, foaming property, emulsifying property, thermal stability, and antioxidant activity). Accordingly, our results indicated that it is feasible for CP or AG to improve the functional properties of CA by the Maillard reaction.

Topics: Caseins; Galactans; Maillard Reaction; Pectins

This study characterised the in vitro ileal fermentability of different substrates in the growing pig, adopted as an animal model for the adult human, and compared in vitro ileal and caecal fermentation in the pig. Substrates (arabinogalactan (AG), cellulose, fructo-oligosaccharide (FOS), inulin, mucin, citrus pectin and resistant starch) were fermented in vitro (ileal 2 h and caecal 24 h) with an ileal or caecal inoculum prepared from ileal or caecal digesta collected from growing pigs (n 5) fed a human-type diet for 15 d. The organic matter (OM) fermentability and production of organic acids were determined. In general, there was considerable in vitro ileal fermentation of fibre, and the substrates differed (P < 0·001) for both in vitro ileal and caecal OM fermentability and for organic acid production. Pectin had the greatest in vitro ileal OM fermentability (26 %) followed by AG, FOS and resistant starch (15 % on average), and cellulose, inulin and mucin (3 % on average). The fermentation of FOS, inulin and mucin was greater for in vitro caecal fermentation compared with the ileal counterpart (P ≤ 0·05). In general, the organic acid production was higher for in vitro caecal fermentation (P ≤ 0·05). For instance, the in vitro ileal acetic acid production represented 4-46 % of in vitro caecal production. Energy from fibre fermentation of 0·6-11 kJ/g substrate fermented could be expected in the ileum of the pig. In conclusion, substrates are fermented in both the ileum and caecum. The degree of fermentation varies among substrates, especially for in vitro ileal fermentation.

Topics: Animals; Bacteria; Cecum; Cellulose; Diet, Western; Dietary Fiber; Digestion; Fermentation; Galactans; Humans; Ileum; Male; Models, Animal; Mucins; Oligosaccharides; Pectins; Starch; Swine

Platycodonis Radix is widely used as homology of medicine and food in China; polysaccharides are thought to be one of its functional constituents. In this study, a pectic polysaccharide, PGP-I-I, was obtained from the root of the traditional medicine plant Platycodon grandiflorus through ion exchange chromatography and gel filtration. This was characterized being mainly composed of 1,5-α-L-arabinan and both arabinogalactan type I (AG-I) and II chains linked to rhamnogalacturonan I (RG-I) backbone linked to longer galacturonan chains. In vitro bioactivity study showed that PGP-I-I could restore the intestinal cellular antioxidant defense under the condition of hydrogen peroxide (H

Topics: Animals; Antioxidants; Cell Line; Chromatography, Gel; Chromatography, Ion Exchange; Dietary Carbohydrates; Galactans; Hydrogen Peroxide; Pectins; Plant Extracts; Plant Roots; Platycodon; Polysaccharides; Swine

Pectin in Diospyros kaki (persimmon) is a complex polysaccharide and is classified as a dietary fiber. Pectin is characterized by the presence of side chains of neutral sugars, such as galactose residues; however, the structure and properties of these sugars vary greatly depending on the plant species from which it is derived. Here, we report the structural features of pectin extracted from persimmon. The polysaccharide was low-methoxy pectin with a degree of methyl esterification <50% and ratio of side chain galactan to arabinan in the rhamnogalacturonan-I region of pectin of 3-20. To investigate the physiological function of pectin from persimmon, we performed a coculture assay using Caco-2 cells. As a result, it was shown that the proliferation of undifferentiated Caco-2 cells was promoted, and further, the importance of arabinogalactan among the pectin structures was shown.

Topics: Caco-2 Cells; Diospyros; Epithelial Cells; Galactans; Humans; Intestine, Small; Pectins

Arabinogalactan-proteins (AGPs) are heavily glycosylated with type II arabinogalactan (AG) polysaccharides attached to hydroxyproline residues in their protein backbone. Type II AGs are necessary for plant growth and critically important for the establishment of normal cellular functions. Despite the importance of type II AGs in plant development, our understanding of the underlying role of these glycans/sugar residues in mucilage formation and seed coat epidermal cell development is poorly understood and far from complete. One such sugar residue is the glucuronic acid residues of AGPs that are transferred onto AGP glycans by the action of β-glucuronosyltransferase genes/enzymes.. Here, we have characterized two β-glucuronosyltransferase genes, GLCAT14A and GLCAT14C, that are involved in the transfer of β-glucuronic acid (GlcA) to type II AGs. Using a reverse genetics approach, we observed that glcat14a-1 mutants displayed subtle alterations in mucilage pectin homogalacturonan (HG) compared to wild type (WT), while glcat14a-1glcat14c-1 mutants displayed much more severe mucilage phenotypes, including loss of adherent mucilage and significant alterations in cellulose ray formation and seed coat morphology. Monosaccharide composition analysis showed significant alterations in the sugar amounts of glcat14a-1glcat14c-1 mutants relative to WT in the adherent and non-adherent seed mucilage. Also, a reduction in total mucilage content was observed in glcat14a-1glcat14c-1 mutants relative to WT. In addition, glcat14a-1glcat14c-1 mutants showed defects in pectin formation, calcium content and the degree of pectin methyl-esterification (DM) as well as reductions in crystalline cellulose content and seed size.. These results raise important questions regarding cell wall polymer interactions and organization during mucilage formation. We propose that the enzymatic activities of GLCAT14A and GLCAT14C play partially redundant roles and are required for the organization of the mucilage matrix and seed size in Arabidopsis thaliana. This work brings us a step closer towards identifying potential gene targets for engineering plant cell walls for industrial applications.

Topics: Arabidopsis; Arabidopsis Proteins; Calcium; Cell Wall; Cellulose; Esterification; Galactans; Glucuronosyltransferase; Monosaccharides; Pectins; Phenotype; Polysaccharides; Seeds

The elucidation of the structural characteristics of polysaccharides from natural sources is generally difficult owing to their structural complexity and heterogeneity. In our previous study, an immuno-stimulatory polysaccharide (RGP-AP-I) was isolated from Korean red ginseng (Panax ginseng C.A. Meyer). The present study aims to elucidate the structural characteristics of RGP-AP-I. Sequential enzyme hydrolysis was performed using four specific glycosylases, and chemical cleavage via β-elimination was carried out to determine the fine structure of RGP-AP-I. The degraded fragments were chemically identified using various chromatographic and spectrometric analyses, including HPLC-UVD, GC-MS, and tandem mass spectrometry. The results indicated that RGP-AP-I comprises a rhamnogalacturonan I (RG-I) backbone with repeating disaccharide units [→2)-Rhap-(1 → 4)-GalAp-(1→] and three side chains substituted at the C(O)4 position of the rhamnose residue in the backbone. The three side chains were identified as a highly branched α-(1 → 5)-arabinan, a branched β-(1 → 4)-galactan, and an arabino-β-3,6-galactan. Our results represent the first findings regarding the fine structure of the immuno-stimulatory polysaccharide RG-AP-I isolated from red ginseng.

Topics: Adjuvants, Immunologic; Chemical Fractionation; Galactans; Glycoside Hydrolases; Hydrolysis; Molecular Structure; Panax; Pectins; Polysaccharides; Structure-Activity Relationship

In this work, high-performance liquid chromatography, fluorescence quenching, nephelometry, and sodium dodecyl sulfate polyacrylamide gel electrophoresis were used to study the effect of polysaccharides naturally present in wine [rhamnogalacturonan II (RG II) and arabinogalactan proteins (AGPs)] on the interaction between salivary proteins (SP) together present in saliva and tannins (punicalagin (PNG) and procyanidin B2). In general, the RG II fraction was more efficient to inhibit SP precipitation by tannins, especially for acidic proline-rich proteins (aPRPs) and statherin/P-B peptide, than AGPs. The RG II fraction can act mainly by a competition mechanism in which polysaccharides compete by tannin binding. However, in the presence of Na

Topics: Chemical Precipitation; Galactans; Humans; Pectins; Polysaccharides; Saliva; Salivary Proteins and Peptides; Tannins; Wine

Topics: Adsorption; Coloring Agents; Cost-Benefit Analysis; Galactans; Hydrogen-Ion Concentration; Kinetics; Methylene Blue; Opuntia; Pectins; Temperature; Thermodynamics; Wastewater; Water; Water Pollutants, Chemical; Water Purification

Cell wall modification is integral to many plant developmental processes where cells need to separate, such as abscission. However, changes in cell wall composition during natural fruit abscission are poorly understood. In olive (Olea europaea L.), some cultivars such as 'Picual' undergo massive natural fruit abscission after fruit ripening. This study investigates the differences in cell wall polysaccharide composition and the localization of pectins and arabinogalactan protein (AGP) in the abscission zone (AZ) during cell separation to understand fruit abscission control in 'Picual' olive. To this end, immunogold labeling employing a suite of monoclonal antibodies to cell wall components (JIM13, LM5, LM6, LM19 and LM20) was investigated in olive fruit AZ. Cell wall polysaccharide extraction revealed that the AZ cell separation is related to the de-esterification and degradation of pectic polysaccharides. Moreover, ultrastructural localization showed that both esterified and unesterified homogalacturonans (HGs) localize mainly in the AZ cell walls, including the middle lamella and tricellular junction zones. Our results indicate that unesterified HGs are likely to contribute to cell separation in the olive fruit AZ. Similarly, immunogold labeling demonstrated a decrease in both galactose-rich and arabinose-rich pectins in AZ cell walls during ripe fruit abscission. In addition, AGPs were localized in the cell wall, plasma membrane and cytoplasm of AZ cells with lower levels of AGPs during ripe fruit abscission. This detailed temporal profile of the cell wall polysaccharide composition, and the pectins and AGP immunolocalization in the olive fruit AZ, offers new insights into cell wall remodeling during ripe fruit abscission.

Topics: Arabinose; Cell Wall; Esterification; Fruit; Galactans; Galactose; Mucoproteins; Olea; Pectins; Plant Proteins; Polysaccharides

Panax notoginseng is a widely used traditional Chinese medicine and has extensive pharmacological effects. In this work, water-soluble polysaccharides from Panax notoginseng were isolated and fractionated. One starch-like polysaccharide (PNPN) and six pectin fractions (PNPA-1A, PNPA-1B, PNPA-2A, PNPA-2B, PNPA-3A and PNPA-3B) were obtained. Monosaccharide composition, enzymatic hydrolysis, nuclear magnetic resonance and methylation analysis were combined to characterize their structures. PNPA-1A and PNPA-2A mainly contained 1,4-β-D-galactans, 1,5-α-L-arabinan and arabinogalactan II (AG-II). PNPA-3A was a typical rhamnogalacturonan I (RG-I) type pectin with 1,4-β-D-galactan and 1,5/1,3,5-α-L-arabinan side chains. PNPA-1B, PNPA-2B and PNPA-3B consisted of homogalacturonan (HG) as major domains, together with different ratios of RG-I and rhamnogalacturonan II (RG-II) domains. These results will provide basis for further investigation of structure-activity relationships of Panax notoginseng polysaccharides and be useful for the application of Panax notoginseng.

Topics: Galactans; Hydrolysis; Magnetic Resonance Spectroscopy; Monosaccharides; Panax notoginseng; Pectins; Polysaccharides; Water

Exotic fruits and their co-products may be valuable sources of antioxidant dietary fibres (DF) which are useful for food industry and human health. In this study, we aimed to characterize DF obtained from guavira fruit pomace and investigate its antioxidant potential employing TEAC assay as well as a cell model. The DF were chemically characterized as containing arabinan, highly-methoxylated homogalacturonan and arabinogalactan. The DF-containing fraction (CPW) presented ABTS free radical scavenger activity. MTT and DCFH-DA assay were performed to assess, respectively, changes in cell viability and the potential intracellular antioxidant activity against H

Topics: Animals; Antioxidants; Cell Survival; Dietary Fiber; Fibroblasts; Fruit; Galactans; Hydrogen Peroxide; Mice; NIH 3T3 Cells; Oxidative Stress; Pectins; Polysaccharides

From the leaves of Silybum marianum L. were isolated arabinogalactan with molecular weight 38 kDa and pectic substances. The monosaccharide composition of arabinogalactan was represented by β-galactose and α-arabinose in a ratio of 2.6:1.0 and β-galacturonic acid as a minor component. By chemical methods and GC, GC-MS, 1D and 2D NMR spectroscopy was established that the arabinogalactan consists of d-galactopyranose residues linked by β-1,6-glycosidic bonds as a main chain, and the side chain was represented by α-arabinose, β-galactose and 4-O-methylglucuronic acid. Pectic substance was found in small amounts. According to NMR data it contains also a branched rhamnogalacturonan.

Topics: Asteraceae; Carbohydrate Sequence; Galactans; Pectins

Changes in the arrangement of cell wall components determine cell wall properties (integrity, stiffness), thereby affecting the macro-scale properties of fruits, which are important for consumers and industry. Arabinogalactan proteins (AGPs) are ubiquitous components of the plant cell, in which they have various functions. Currently, AGPs are considered to be one of the less well-known, enigmatic proteoglycans, a consequence of their heterogeneous structure and unclear mechanism of activity.. An immunocytochemical study was conducted to elucidate the distribution of AGPs and pectic polysaccharides contained in apple (Malus × domestica) fruit during senescence. De-esterified homogalacturonan (LM19), methyl-esterified homogalacturonan (LM20), processed arabinan (LM16) and three AGP epitopes (JIM13, JIM15, MAC207) were identified in the fruit at three stages: fresh fruit, and fruit at 1 and 3 months of post-harvest storage.. Microscopy revealed spatio-temporal changes in the localization of all examined epitopes. Changes of fruit cell wall assembly and its degradation were confirmed by determination of the galacturonic acid content in the WSP (water soluble pectins), CSP (chelator soluble pectins) and DASP (dilute alkali soluble pectins) fractions.. The results revealed dependencies between AGPs, arabinan and homogalacturonan distribution in apple fruit, which are correlated with changes in microstructure during senescence. We propose that AGPs are involved in establishment of the cell wall - plasma membrane continuum.

Topics: Food Storage; Fruit; Galactans; Malus; Pectins; Plant Proteins

l-Arabinose and d-galactose are the principal constituents of l-arabinogalactan, and also co-occur in other hemicelluloses and pectins. In this work we hypothesized that similar to the induction of relevant glycoside hydrolases by monomers liberated from these plant heteropolymers, their respective catabolisms in saprophytic and phytopathogenic fungi may respond to the presence of the other sugar to promote synergistic use of the complex growth substrate. We showed that these two sugars are indeed consumed simultaneously by Aspergillus nidulans, while l-arabinose is utilised faster in the presence than in the absence of d-galactose. Furthermore, the first two genes of the Leloir pathway for d-galactose catabolism - encoding d-galactose 1-epimerase and galactokinase - are induced more rapidly by l-arabinose than by d-galactose eventhough deletion mutants thereof grow as well as a wild type strain on the pentose. d-Galactose 1-epimerase is hyperinduced by l-arabinose, d-xylose and l-arabitol but not by xylitol. The results suggest that in A. nidulans, l-arabinose and d-xylose - both requiring NADPH for their catabolisation - actively promote the enzyme infrastructure necessary to convert β-d-galactopyranose via the Leloir pathway with its α-anomer specific enzymes, into β-d-glucose-6-phosphate (the starting substrate of the oxidative part of the pentose phosphate pathway) even in the absence of d-galactose.

Topics: Arabinose; Aspergillus nidulans; Galactans; Galactose; Gene Expression Regulation, Fungal; Metabolic Networks and Pathways; Metabolism; Pectins; Polysaccharides; UDPglucose 4-Epimerase; Xylose

The chemical and sensory profiles of wines prepared from Cabernet Sauvignon grapes at different ripening stages vary greatly. Here, the soluble cell wall carbohydrate (SCWC) and phenolic profiles of wines were analyzed in parallel with the sensory evaluation of their mouthfeel and taste characteristics. Both SCWCs and phenolic compounds correlated with wine mouthfeel. When analyses were extended to specific classes of cell wall carbohydrates, it was shown that rhamnogalacturonan I/II, arabinan, arabinogalactan types I and II and xyloglucan from grapes were the key determinants of overall mouthfeel descriptors, particularly viscosity, astringency and roughness, whereas heteromannan from grapes was associated with mouth coating and chalkiness. A perceived sour taste was notably associated with higher homogalacturonan contents. This finding provides insights into the contributions of non-phenolic compounds to wine mouthfeel. The data provide opportunities for the development of simple monosaccharide marker assays to monitor major mouthfeel characteristics in red wines.

Topics: Astringents; Carbohydrates; Cell Wall; Galactans; Humans; Molecular Weight; Mouth; Pectins; Phenols; Taste; Vitis; Wine

Artemisia afra (Jacq. Ex. Willd), is an indigenous plant in South Africa and other parts of the African continent, where it is used as traditional medicine mostly for respiratory conditions. The objective of this study was to investigate the structural features of the polysaccharides from the leaves of this plant, as well as the biological activities of the polysaccharide fractions against the complement assay. Leaves of Artemisia afra were extracted sequentially with organic solvents (dichloromethane and methanol), 50% aqueous ethanol, and water at 50 and 100°C respectively. The polysaccharide extracts were fractionated by ion exchange chromatography and the resulting fractions were tested for biological activity against the complement fixation assay. Active fractions were further fractionated using gel filtration. Monosaccharide compositions and linkage analyses were determined for the relevant fractions. Polysaccharides were shown to be of the pectin type, and largely contain arabinogalactan, rhamnogalacturonan and homogalacturonan structural features. The presence of arabinogalactan type II features as suggested by methylation analysis was further confirmed by the ready precipitation of the relevant polysaccharides with the Yariv reagent. An unusual feature of some of these polysaccharides was the presence of relatively high levels of xylose as one of its monosaccharide constituents. Purified polysaccharide fractions were shown to possess higher biological activity than the selected standard in the complement assay. Digestion of these polysaccharides with an endo-polygalacturonase enzyme resulted in polymers with lower molecular weights as expected, but still with biological activity which exceeded that of the standard. Thus on the basis of these studies it may be suggested that immunomodulating properties probably contribute significantly to the health-promoting effects of this medicinal plant.

Topics: Artemisia; Complement Fixation Tests; Galactans; Pectins; Plant Extracts; Plant Leaves; Plants, Medicinal; Polysaccharides; South Africa; Structure-Activity Relationship

Purification, characterization and biological activities of polysaccharides from Lycium barbarum pedicel were investigated in this study. Two polysaccharides, PLBP-I-I and PLBP-II-I, were obtained from water extracts by anion exchange chromatography and gel filtration. Structural elucidation based on IR,

Topics: Antioxidants; Galactans; Hexuronic Acids; Immunologic Factors; Lycium; Magnetic Resonance Spectroscopy; Pectins; Plant Extracts; Polysaccharides

During somatic embryogenesis (SE), explant cells undergo changes in the direction of their differentiation, which lead to diverse cell phenotypes. Although the genetic bases of the SE have been extensively studied in Arabidopsis thaliana, little is known about the chemical characteristics of the wall of the explant cells, which undergo changes in the direction of differentiation. Thus, we examined the occurrence of selected pectic and AGP epitopes in explant cells that display different phenotypes during SE. Explants examinations have been supplemented with an analysis of the ultrastructure. The deposition of selected pectic and AGP epitopes in somatic embryos was determined. Compared to an explant at the initial stage, a/embryogenic/totipotent and meristematic/pluripotent cells were characterized by a decrease in the presence of AGP epitopes, b/the presence of AGP epitopes in differentiated cells was similar, and c/an increase of analyzed epitopes was detected in the callus cells. Totipotent cells could be distinguished from pluripotent cells by: 1/the presence of the LM2 epitope in the latest one, 2/the appearance of the JIM16 epitope in totipotent cells, and 3/the more abundant presence of the JIM7 epitope in the totipotent cells. The LM5 epitope characterized the wall of the cells that were localized within the mass of embryogenic domain. The JIM8, JIM13 and JIM16 AGP epitopes appeared to be the most specific for the callus cells. The results indicate a relationship between the developmental state of the explant cells and the chemical composition of the cell walls.

Topics: Arabidopsis; Arabidopsis Proteins; Galactans; Pectins; Plant Cells; Plant Somatic Embryogenesis Techniques

The cell wall is an essential framework determining the overall form of the plant cell. Our study was focused on the distribution of arabinogalactan proteins (AGPs), arabinan, and homogalacturonan in fruit cells during ripening and storage with emphasis on quantitative analysis of their presence in particular regions of the cell wall - plasma membrane. The localization of the examined compounds was determined with immunohistochemistry techniques and immunogold labelling. Spatio-temporal colocalization between AGPs epitopes - [βGlcA(1→3)-αGalA(1→2)Rha] recognized by JIM13 and MAC207 antibodies, and arabinan labelled by the LM16 antibody was detected in the inner cell wall layer, in association with the plasma membrane. The specific arrangement of AGP and arabinan epitopes differentiated them from homogalacturonan epitopes, consisting of GalA residues recognized by LM19 and LM20 antibodies in all the examined fruit maturity stages. The disruption of cell wall - plasma membrane continuum, observed during ripening-associated softening process, was associated with both the substantial decrease of AGPs, pectins content and with remodeling of their arrangement. The results indicate that the textural properties of fruit during growth and postharvest storage, an attribute of fruit quality becoming selection criteria for consumers, depend on the existence of dynamic network organizing polysaccharides and glycoproteins in the extracellular matrix.

Topics: Cell Membrane; Cell Wall; Food Storage; Fruit; Galactans; Malus; Microscopy, Electron, Transmission; Pectins; Plant Proteins; Proteoglycans

Pollen exine is essential for protection from the environment of the male gametes of seed-producing plants, but its assembly and composition remain poorly understood. We previously characterized Arabidopsis (Arabidopsis thaliana) mutants with abnormal pollen exine structure and morphology that we named kaonashi (kns). Here we describe the identification of the causal gene of kns4 that was found to be a member of the CAZy glycosyltransferase 31 gene family, identical to UNEVEN PATTERN OF EXINE1, and the biochemical characterization of the encoded protein. The characteristic exine phenotype in the kns4 mutant is related to an abnormality of the primexine matrix laid on the surface of developing microspores. Using light microscopy with a combination of type II arabinogalactan (AG) antibodies and staining with the arabinogalactan-protein (AGP)-specific β-Glc Yariv reagent, we show that the levels of AGPs in the kns4 microspore primexine are considerably diminished, and their location differs from that of wild type, as does the distribution of pectin labeling. Furthermore, kns4 mutants exhibit reduced fertility as indicated by shorter fruit lengths and lower seed set compared to the wild type, confirming that KNS4 is critical for pollen viability and development. KNS4 was heterologously expressed in Nicotiana benthamiana, and was shown to possess β-(1,3)-galactosyltransferase activity responsible for the synthesis of AG glycans that are present on both AGPs and/or the pectic polysaccharide rhamnogalacturonan I. These data demonstrate that defects in AGP/pectic glycans, caused by disruption of KNS4 function, impact pollen development and viability in Arabidopsis.

Topics: Arabidopsis; Arabidopsis Proteins; Biopolymers; Carotenoids; Epitopes; Fertility; Galactans; Galactosyltransferases; Gene Expression Regulation, Plant; Genes, Plant; Models, Biological; Mutation; Pectins; Phenotype; Pollen

Piper nigrum L. fruits are not only a prized spice, but also highly valued therapeutic agent that heals many ailments including asthma, cold and respiratory problems. Herein, we have investigated structural features and in vivo antitussive activity of three fractions isolated from Piper nigrum fruits. The water extract (PN-WE) upon fractionation with EtOH yielded two fractions: a soluble fraction (PN-eSf) and a precipitated (PN-ePf) one. The existence of a pectic polysaccharide with arabinogalactan type II side chains (147kDa) in PN-ePf and piperine in PN-eSf were revealed. Moreover, oligosaccharides providing fine structural details of side chains were generated from PN-ePf and then characterized. The parental water extract (PN-WE) that contained both pectic polysaccharide and piperine, after oral administration (50mgkg

Topics: Animals; Antitussive Agents; Cough; Drug Synergism; Ethanol; Fruit; Galactans; Guinea Pigs; Male; Monosaccharides; Pectins; Piper nigrum; Piperidines; Reflex; Respiratory System; Solubility; Water

It is established that arabinogalactan and pectinaceous polysaccharides isolated from Ferula kuchistanica are capable of stimulating a primary immune response in mice by increasing the number of antibody-producing cells in the spleen in response to immunization with sheep red blood cells in both intact animals (on average by 51.0%; p < 0.005) and those with secondary immunodeficiency caused by irradiation (on average by 164.4%; p < 0.005). The treatment with compounds studied also significantly increased the functional condition of cells of the mononuclear phagocyte system (on average by 27.0%; p < 0.005).

Topics: Adjuvants, Immunologic; Animals; Disease Models, Animal; Female; Ferula; Galactans; Immunologic Deficiency Syndromes; Male; Mice; Pectins; Phagocytes

Pectins are a group of structurally complex plant cell wall polysaccharides whose biosynthesis and function remain poorly understood. The pectic polysaccharide rhamnogalacturonan-I (RG-I) has two types of arabinogalactan side chains, type-I and type-II arabinogalactans. To date few enzymes involved in the biosynthesis of pectin have been described. Here we report the identification of a highly conserved putative glycosyltransferase encoding gene, Pectic ArabinoGalactan synthesis-Related (PAGR), affecting the biosynthesis of RG-I arabinogalactans and critical for pollen tube growth.. T-DNA insertions in PAGR were identified in Arabidopsis thaliana and were found to segregate at a 1:1 ratio of heterozygotes to wild type. We were unable to isolate homozygous pagr mutants as pagr mutant alleles were not transmitted via pollen. In vitro pollen germination assays revealed reduced rates of pollen tube formation in pollen from pagr heterozygotes. To characterize a loss-of-function phenotype for PAGR, the Nicotiana benthamiana orthologs, NbPAGR-A and B, were transiently silenced using Virus Induced Gene Silencing. NbPAGR-silenced plants exhibited reduced internode and petiole expansion. Cell wall materials from NbPAGR-silenced plants had reduced galactose content compared to the control. Immunological and linkage analyses support that RG-I has reduced type-I arabinogalactan content and reduced branching of the RG-I backbone in NbPAGR-silenced plants. Arabidopsis lines overexpressing PAGR exhibit pleiotropic developmental phenotypes and the loss of apical dominance as well as an increase in RG-I type-II arabinogalactan content.. Together, results support a function for PAGR in the biosynthesis of RG-I arabinogalactans and illustrate the essential roles of these polysaccharides in vegetative and reproductive plant growth.

Topics: Arabidopsis; Arabidopsis Proteins; Fertility; Galactans; Gene Expression Regulation, Plant; Gene Silencing; Genotype; Glycosyltransferases; Golgi Apparatus; Immunoblotting; Luminescent Proteins; Microscopy, Confocal; Mutation; Nicotiana; Pectins; Phenotype; Plants, Genetically Modified; Pollen; Pollen Tube; Reverse Transcriptase Polymerase Chain Reaction

Arabinogalactan proteins (AGP) and pectic polysaccharides were isolated from above-ground parts of Heracleum sosnowskyi. The structural study has shown that a linear region of the pectic macromolecules consists of 1,4-α-d-galactopyranosyluronan blocks partially methyl esterified and acetylated. The branched region consists of 3-O- and partially 2-O-acetylated rhamnogalacturonan I. Side chains of the RG-I backbone include the regions of arabinogalactan I and branched 1,5-α-l-arabinan. The carbohydrate part of AGP consists of arabinogalactan II with a 1,3-β-d-Galp main chain. The side chains of the branched area of AG-II are composed of 1,6-β-d-Galp, 1,5-, 1,3,5-α-l-Araf, 4-O-Me-β-d-GlcA and 1,4-β-d-GlcpA, and non-reducing ends residues of β-d-Galp, α-l-Araf, α-l-Rhap and α-l-Fucp. The branch points of the main and side chains are formed by 3,6-di-O-substituted β-d-Galp. It was found that at least a portion of pectin is probably covalently linked to AGP, wherein AGP is linked to RG-I, but not with galacturonan.

Topics: Galactans; Heracleum; Magnetic Resonance Spectroscopy; Mucoproteins; Oxalates; Pectins; Plant Proteins; Polysaccharides; Solubility

Maple syrup is a widely consumed plant-derived natural sweetener produced by concentrating xylem sap collected from certain maple (Acer) species. During thermal evaporation of water, natural phytochemical components are concentrated in maple syrup. The polymeric components from maple syrup were isolated by ethanol precipitation, dialysis, and anion exchange chromatography and structurally characterized by glycosyl composition analysis, glycosyl linkage analysis, and nuclear magnetic resonance spectroscopy. Among the maple syrup polysaccharides, one neutral polysaccharide was characterized as inulin with a broad molecular weight distribution, representing the first isolation of this prebiotic carbohydrate from a xylem sap. In addition, two acidic polysaccharides with structural similarity were identified as arabinogalactans derived from rhamnogalacturonan type I pectic polysaccharides.

Topics: Acer; Galactans; Inulin; Molecular Weight; Nutritive Sweeteners; Pectins; Prebiotics

The aim of this research is to investigate the effects of the Agrobacterium rhizogenes rol genes on the composition of cell-wall polysaccharides and glycanase activity in the campion callus. The expression of the rolC gene reduces the yield of campion pectin, while the expression of the rolB or rolC gene inhibits the volumetric production of both pectin and intracellular arabinogalactan. The rol genes are involved in regulating the activity of glycanases and esterases, thereby contributing to the modification of polysaccharide structures, their molecular weight (Mw) and the degree of pectin methyl esterification (DE). The increase in pectin arabinose residue appears to be connected to a decrease in intracellular and extracellular α-l-arabinofuranosidase activity in transgenic campion calluses. In transgenic calluses expressing the rolB and rolC genes, the increase in pectin galactose residue is likely due to a decrease in β-galactosidase activity. The decrease in the Mw of pectin and its d-galacturonic acid content appears to be connected to an increase in extracellular polygalacturonase activity. Finally, the increase in pectinesterase activity causes a decrease in the DE of pectin. Thus, the expression of rolB and rolC genes in campion callus has a considerable effect on pectin's sugar composition, DE and Mw, while it appears to have an insignificant influence on intracellular and extracellular arabinogalactans.

Topics: Agrobacterium; Bacterial Proteins; Cell Wall; Galactans; Glycoside Hydrolases; Pectins; Polysaccharides

A structural characterization of polysaccharides obtained from edible tropical fruit named starfruit (Averrhoa carambola L.) was carried out. After fractionation by freeze-thaw and Fehling precipitation, a pectic polysaccharide was obtained. It was composed of rhamnose, arabinose, galactose and uronic acid in the 5.0:72.5:12.1:10.4 molar ratios, respectively. A combination of monosaccharide, GPC, methylation and NMR analysis and enzymatic hydrolysis with endo-β-(1→4)-D-galactanase showed the presence of a rhamnogalacturonan I to which a branched arabinan and a type I arabinogalactan are attached. The arabinan moiety was formed by (1→5)-linked α-L-Araf units in the backbone, branched only at O-3 by (1→2)- and (1→3)-linked α-L-Araf units, while the type I arabinogalactan was formed by (1→4)- and (1→4,6)-linked β-D-Galp units in the backbone with (1→5)-, (1→3,5)- and (1→3)-linked α-L-Araf units as side chains.

Topics: Galactans; Oxalidaceae; Pectins

Corn pectic polysaccharide (COPP) inhibited galectin-3 mediated hemagglutination at Minimum Inhibitory Concentration (MIC) of 4.08 μg/mL as opposed to citrus pectin (25 μg/mL), a well known galectin-3 inhibitor and lactose (4.16 μg/mL)--sugar specific to galectin-3. COPP effectively (72%) inhibited invasion and metastasis in experimental animals. In vivo results were substantiated by modulation of cancer specific markers such as galectin-3, which is a key molecule for initiation of metastatic cascade, vascular endothelial growth factor (VEGF) that enhances angiogenesis, matrix metalloproteinases 2 and 9 that are required for invasion, NF-κB, a transcription factor for proliferative potency of tumor cells and a phosphoglucoisomerase (PGI), the activity of which favors cancer cell growth. Structural characterization studies indicate the active component (relatively less acidic, 0.05 M ammonium carbonate, 160 kDa fraction) which showed antimetastatic potency in vitro with MIC of 0.09 μg/mL, and ∼ 45 fold increase in the activity when compared to that of COPP. Gas liquid chromatographic analysis indicated the presence of rhamnose (1%), arabinose (20%), xylose (3%), mannose (4%), galactose (54%) and uronic acid (10%) in different proportions. However, correlative data attributed galectin-3 inhibitory activity to enhanced levels of arabinose and galactose. FTIR, HPLC and NMR spectroscopic analysis further highlights that COPP is an arabinogalactan with methyl/ethyl esters. It is therefore suggested that the blockade of galectin-3 mediated lung metastasis appears to be a result of an inhibition of mixed functions induced during metastasis. The data signifies the importance of dietary carbohydrate as cancer-preventive agent. Although pectin digestibility and absorption are issues of concern, promising in vivo data provides evidence for the cancer preventive property of corn. The present study reveals for the first time a new component of corn, i.e.,--corn pectin with cancer preventive activity apart from corn starch that has been in wide use for multipurpose health benefits.

Topics: Animals; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Neoplastic; Dietary Carbohydrates; Galactans; Galectin 3; Melanoma, Experimental; Neoplasm Metastasis; Neovascularization, Pathologic; NF-kappa B; Pectins; Polysaccharides; Vascular Endothelial Growth Factor A; Zea mays

Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

Topics: beta-Galactosidase; Biopolymers; Cell Wall; Cellulose; Galactans; Galactose; Gelatin; Glucans; Microfibrils; Models, Biological; Pectins; Polysaccharides; Populus; Wood; Xylans

Rhamnogalacturonan I (RGI) is a pectic polysaccharide composed of a backbone of alternating rhamnose and galacturonic acid residues with side chains containing galactose and/or arabinose residues. The structure of these side chains and the degree of substitution of rhamnose residues are extremely variable and depend on species, organs, cell types and developmental stages. Deciphering RGI function requires extending the current set of monoclonal antibodies (mAbs) directed to this polymer. Here, we describe the generation of a new mAb that recognizes a heterogeneous subdomain of RGI. The mAb, INRA-AGI-1, was produced by immunization of mice with RGI oligosaccharides isolated from potato tubers. These oligomers consisted of highly branched RGI backbones substituted with short side chains. INRA-AGI-1 bound specifically to RGI isolated from galactan-rich cell walls and displayed no binding to other pectic domains. In order to identify its RGI-related epitope, potato RGI oligosaccharides were fractionated by anion-exchange chromatography. Antibody recognition was assessed for each chromatographic fraction. INRA-AGI-1 recognizes a linear chain of (1→4)-linked galactose and (1→5)-linked arabinose residues. By combining the use of INRA-AGI-1 with LM5, LM6 and INRA-RU1 mAbs and enzymatic pre-treatments, evidence is presented of spatial differences in RGI motif distribution within individual cell walls of potato tubers and carrot roots. These observations raise questions about the biosynthesis and assembly of pectin structural domains and their integration and remodeling in cell walls.

Topics: Animals; Cell Wall; Daucus carota; Epitopes; Galactans; Mice; Pectins; Plant Roots; Polysaccharides; Solanum tuberosum

Type VI glandular trichomes represent the most abundant trichome type on leaves and stems of tomato plants and significantly contribute to herbivore resistance, particularly in the wild species. Despite this, their development has been poorly studied so far. The goal of this study is to fill this gap. Using a variety of cell imaging techniques, a detailed record of the anatomy and developmental stages of type VI trichomes in the cultivated tomato (Solanum lycopersicum) and in a related wild species (S. habrochaites) is provided.. In both species, the development of these structures follows a highly reproducible cell division pattern. The two species differ in the shape of the trichome head which is round in S. habrochaites and like a four-leaf clover in S. lycopersicum, correlating with the presence of a large intercellular cavity in S. habrochaites where the produced metabolites accumulate. In both species, the junction between the intermediate cell and the four glandular cells constitute a breaking point facilitating the decapitation of the trichome and thereby the quick release of the metabolites. A strongly auto-fluorescent compound transiently accumulates in the early stages of development suggesting a potential role in the differentiation process. Finally, immuno-labelling with antibodies recognizing specific cell wall components indicate a key role of pectin and arabinogalactan components in the differentiation of type VI trichomes.. Our observations explain the adaptive morphologies of type VI trichomes for metabolite storage and release and provide a framework for further studies of these important metabolic cellular factories. This is required to better exploit their potential, in particular for the breeding of pest resistance in tomato.

Topics: Galactans; Pectins; Solanum; Trichomes

In Malian traditional medicine infusions of the roots of Vernonia kotschyana or Cochlospermum tinctorium in water are used for treating gastric ulcer. Helicobacter pylori is known to play a major role in gastric ulcer development, and it was of interest to evaluate a potential anti-adhesive activity towards H. pylori by crude water extracts and isolated polysaccharide fractions from the roots of V. kotschyana and C. tinctorium. The inhibitory effects were examined by an in vitro flow cytometric assay using human gastric adenocarcinoma epithelial cells, where fluorescent-labeled H. pylori were pre-treated with the test fractions. The crude extract Ctw50 from C. tinctorium, containing a mixture of inulin, pectic polysaccharides, phenols and protein, led to a 43% reduction of bacterial attachment. The isolated pectic type fractions CtwA1 and CtwA2 from C. tinctorium, and Vko-I from V. kotschyana resulted in approximately 30% inhibition of H. pylori adhesion. These fractions consist of rhamnogalacturonan backbones with side chains of arabinogalactans and/or arabinans. The low degree of uronic acids in the fractions compared to anti-adhesive polysaccharides reported previously, suggests that the neutral side chains might play a role in the binding of bacterial adhesins. The fraction Vko-III.1 from V. kotschyana consisting mainly of galacturonic acid resulted only in a 19% inhibition of H. pylori adhesion. The anti-adhesive properties shown by the crude water extracts and isolated polysaccharide fractions in the present study might partly explain the anti-ulcer activities by the roots of V. kotschyana and C. tinctorium.

Topics: Adenocarcinoma; Bixaceae; Cell Adhesion; Epithelial Cells; Galactans; Helicobacter pylori; Humans; Medicine, Traditional; Pectins; Phenols; Plant Extracts; Plant Roots; Polysaccharides; Stomach Ulcer; Vernonia

Arabinogalactan protein 31 (AGP31) is a remarkable plant cell-wall protein displaying a multi-domain organization unique in Arabidopsis thaliana: it comprises a predicted signal peptide (SP), a short AGP domain of seven amino acids, a His-stretch, a Pro-rich domain and a PAC (PRP-AGP containing Cys) domain. AGP31 displays different O-glycosylation patterns with arabinogalactans on the AGP domain and Hyp-O-Gal/Ara-rich motifs on the Pro-rich domain. AGP31 has been identified as an abundant protein in cell walls of etiolated hypocotyls, but its function has not been investigated thus far. Literature data suggest that AGP31 may interact with cell-wall components. The purpose of the present study was to identify AGP31 partners to gain new insight into its function in cell walls.. Nitrocellulose membranes were prepared by spotting different polysaccharides, which were either obtained commercially or extracted from cell walls of Arabidopsis thaliana and Brachypodium distachyon. After validation of the arrays, in vitro interaction assays were carried out by probing the membranes with purified native AGP31 or recombinant PAC-V5-6xHis. In addition, dynamic light scattering (DLS) analyses were carried out on an AGP31 purified fraction.. It was demonstrated that AGP31 interacts through its PAC domain with galactans that are branches of rhamnogalacturonan I. This is the first experimental evidence that a PAC domain, also found as an entire protein or a domain of AGP31 homologues, can bind carbohydrates. AGP31 was also found to bind methylesterified polygalacturonic acid, possibly through its His-stretch. Finally, AGP31 was able to interact with itself in vitro through its PAC domain. DLS data showed that AGP31 forms aggregates in solution, corroborating the hypothesis of an auto-assembly.. These results allow the proposal of a model of interactions of AGP31 with different cell-wall components, in which AGP31 participates in complex supra-molecular scaffolds. Such scaffolds could contribute to the strengthening of cell walls of quickly growing organs such as etiolated hypocotyls.

Topics: Arabidopsis; Arabidopsis Proteins; Brachypodium; Cell Wall; Galactans; Glycosylation; Models, Biological; Mucoproteins; Nicotiana; Pectins; Plant Proteins; Polysaccharides; Protein Binding; Protein Structure, Tertiary; Recombinant Proteins; Seedlings

Two pectic polysaccharides, 50 WCP-II-I and 100 WCP-II-I, were obtained from 50 and 100 °C water extracts of Codonopsis pilosula roots by ion exchange chromatography and gel filtration. The study of the sub-fractions obtained after pectinase degradation showed that the complement fixation activities of these pectins are expressed mainly by their ramified regions. The structure studies of native and sub-fractions showed the 50 WCP-II-I is a pectic polysaccharide, with long homogalacturonan regions (some of the galacturonic acid units were methyl esterified), interrupted by one short rhamnogalacturonan I (RG-I) region. The side chains of the RG-I region are arabinogalactan type I (AG-I) and type II (AG-II) attached on position 4 of rhamnose. The 100 WCP-II-I has two main ramified regions, one is galacturonan region with AG-I side chain on position 2 of GalA, and the other one is RG-I region with AG-II side chain on position 4 of Rha.

Topics: Chromatography, Gel; Chromatography, Ion Exchange; Codonopsis; Galactans; Hexuronic Acids; Pectins; Plant Roots; Polysaccharides; Water

Coffee plants were subjected to heat stress (37 °C) and compared with control plants (24 °C). Cell wall polysaccharides were extracted using water (W), EDTA (E) and 4M NaOH (H30 and H70). In addition, monolignols were analyzed, and the leaves were observed by microscopy. Plants under heat stress accumulated higher contents of arabinose and galactose in fraction W. Xylose contents were observed to decrease in H30 fractions after the heat stress, whereas galactose and uronic acid increased. H70 fractions from plants exposed to heat stress showed increased xylose contents, whereas the contents of arabinose and glucose decreased. Differences in the molar-mass profiles of polysaccharides were also observed. The primary monolignol contents increased after the heat stress. Structural alterations in palisade cells and ultrastructural damage in chloroplasts were also observed. Our results demonstrate that the chemical profile of coffee cell-wall polymers and structural cell anatomy change under heat stress.

Topics: Arabinose; Cell Wall; Chromatography, Gel; Coffea; Galactans; Hot Temperature; Lignin; Pectins; Plant Cells; Plant Leaves; Polysaccharides; Stress, Physiological; Uronic Acids; Water

Cell wall pectins and arabinogalactan proteins (AGPs) are important for pollen tube growth. The aim of this work was to study the temporal and spatial dynamics of these compounds in olive pollen during germination.. Immunoblot profiling analyses combined with confocal and transmission electron microscopy immunocytochemical detection techniques were carried out using four anti-pectin (JIM7, JIM5, LM5 and LM6) and two anti-AGP (JIM13 and JIM14) monoclonal antibodies.. Pectin and AGP levels increased during olive pollen in vitro germination. (1 → 4)-β-d-Galactans localized in the cytoplasm of the vegetative cell, the pollen wall and the apertural intine. After the pollen tube emerged, galactans localized in the pollen tube wall, particularly at the tip, and formed a collar-like structure around the germinative aperture. (1 → 5)-α-l-Arabinans were mainly present in the pollen tube cell wall, forming characteristic ring-shaped deposits at regular intervals in the sub-apical zone. As expected, the pollen tube wall was rich in highly esterified pectic compounds at the apex, while the cell wall mainly contained de-esterified pectins in the shank. The wall of the generative cell was specifically labelled with arabinans, highly methyl-esterified homogalacturonans and JIM13 epitopes. In addition, the extracellular material that coated the outer exine layer was rich in arabinans, de-esterified pectins and JIM13 epitopes.. Pectins and AGPs are newly synthesized in the pollen tube during pollen germination. The synthesis and secretion of these compounds are temporally and spatially regulated. Galactans might provide mechanical stability to the pollen tube, reinforcing those regions that are particularly sensitive to tension stress (the pollen tube-pollen grain joint site) and mechanical damage (the tip). Arabinans and AGPs might be important in recognition and adhesion phenomena of the pollen tube and the stylar transmitting cells, as well as the egg and sperm cells.

Topics: Electrophoresis; Galactans; Germination; Immunohistochemistry; Microscopy, Electron, Transmission; Olea; Pectins; Pollen Tube

To enable structural characteristics of individual cell wall polysaccharides from rapeseed (Brassica napus) meal (RSM) to be studied, polysaccharide fractions were sequentially extracted. Fractions were analysed for their carbohydrate (linkage) composition and polysaccharide structures were also studied by enzymatic fingerprinting. The RSM fractions analysed contained pectic polysaccharides: homogalacturonan in which 60% of the galacturonic acid residues are methyl-esterified, arabinan branched at the O-2 position and arabinogalactan mainly type II. This differs from characteristics previously reported for Brassica campestris meal, another rapeseed cultivar. Also, in the alkali extracts hemicelluloses were analysed as xyloglucan both of the XXGG- and XXXG-type decorated with galactosyl, fucosyl and arabinosyl residues, and as xylan with O-methyl-uronic acid attached. The final residue after extraction still contained xyloglucan and remaining (pectic) polysaccharides next to cellulose, showing that the cell wall matrix of RSM is very strongly interconnected.

Topics: Brassica napus; Carbohydrate Sequence; Cell Wall; Chromatography, Ion Exchange; Enzyme Assays; Galactans; Glucans; Hexuronic Acids; Molecular Sequence Data; Pectins; Polysaccharides; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Xylans

Date palm (Phoenix dactylifera) is an important crop providing a valuable nutrition source for people in many countries including the Middle East and North Africa. In recent years, the amount of rain in North Africa and especially in the Tunisian palm grove areas has dropped significantly. We investigated the growth and cell wall remodelling of fruits harvested at three key development stages from trees grown with or without water supply. During development, cell wall solubilization and remodelling was characterized by a decrease of the degree of methylesterification of pectin, an important loss of galactose content and a reduction of the branching of xylan by arabinose in irrigated condition. Water deficit had a profound effect on fruit size, pulp content, cell wall composition and remodelling. Loss of galactose content was not as important, arabinose content was significantly higher in the pectin-enriched extracts from non-irrigated condition, and the levels of methylesterification of pectin and O-acetylation of xyloglucan were lower than in irrigated condition. The lower levels of hydrophobic groups (methylester and O-acetyl) and the less intensive degradation of the hydrophilic galactan, arabinan and arabinogalactan in the cell wall may be implicated in maintaining the hydration status of the cells under water deficit.

Topics: Acetylation; Arecaceae; Cell Wall; Dehydration; Esterification; Fruit; Galactans; Galactose; Glucans; Hydrophobic and Hydrophilic Interactions; Pectins; Polysaccharides; Solubility; Water; Xylans

The late stages of microsporogenesis in the family Cyperaceae are marked by the formation of an asymmetrical tetrad, degeneration of three of the four nuclei resulting from meiosis and the formation of pseudomonads. In order to understand the cytological changes involved in the development of pseudomonads, a combination of 11 different techniques (conventional staining, cytochemistry procedures, immunofluorescence, FISH and transmission electron microscopy: TEM) were used to study the later stages of microsporogenesis in Rhynchospora pubera. The results demonstrated the occurrence of two cytoplasmic domains in the pseudomonads, one functional and the other degenerative, which are physically and asymmetrically separated by cell plate with an endomembrane system rich in polysaccharides. Other changes associated with endomembrane behaviour were observed, such as a large number of lipid droplets, vacuoles containing electron-dense material and concentric layers of endoplasmic reticulum. Concomitant with the isolation of degenerative nuclei, the tapetal cells also showed evidence of degeneration, indicating that both tissues under programmed cell death (PCD), as indicated by immunofluorescence and TEM procedures. The results are significant because they associate cellular polarisation and asymmetry with different cytoplasmic domains, and hence open new possibilities for studying cellular compartmentalisation and PCD.

Topics: Apoptosis; Base Sequence; Cell Nucleus; Cell Wall; Cyperaceae; Cytokinesis; Galactans; Pectins; Pollen

Pulp from peaches contained polygalacturonic acid and arabinogalactan as main polysaccharides, which were isolated and characterised. The polygalacturonic acid (AE-CWI) contained 95% GalA and its (13)C NMR spectrum showed signals at δ 98.9, 78.0, 71.4, 69.1, 68.4, and 175.1 from C-1, C-4, C-5, C-3, C-2, and C-6 respectively, from (1→4)-linked α-GalpA units. Methylation-MS analysis of carboxy-reduced material (AE-CWI-CR) gave 90% of 2,3,6-Me(3)-galactitol acetate. The arabinogalactan (AE-AG) was composed mainly of Ara (41%) and Gal (50%) and was characterised (methylation analysis and (13)C NMR) as a type II-arabinogalactan. It induced peritoneal macrophage activation in mice, ~70% of cells treated with this fraction (1-50 μg/mL) having morphology of activated cells. However, NO production in macrophages treated with AE-AG was not affected. This suggests a new biological activity for peach polysaccharides.

Topics: Animals; Galactans; Macrophages, Peritoneal; Male; Mice; Molecular Structure; Pectins; Plant Extracts; Prunus

The pH-modified citrus pectin (MCP) has been demonstrated to inhibit galectin-3 in cancer progression. The components and structures of MCP related to this inhibition remained unknown. In this paper, we fractionated MCP on DEAE-cellulose column into a homogenous neutral fraction MCP-N (about 20 kDa) and a pectin mixture fraction MCP-A (wide molecular distribution on Sepharose CL-6B chromatography). Both MCP-N and MCP-A inhibited hemagglutination mediated by galectin-3 with minimum inhibition concentration (MIC) 625 and 0.5 μg/ml, respectively. MCP-N was identified to be a type I arabinogalactan (AG-I) with a main chain of β-1→4-galactan. MCP-N was digested by α-L-arabinofuranosidase to give its main chain structure fraction (M-galactan, around 18 kDa), which was more active than the original molecule, MIC 50 μg/ml. The acidic degradation of M-galactan increased the inhibitory activity, MIC about 5 times lower than M-galactan. These results above showed that the functional motif of the β-1→4-galactan fragment might lie in the terminal residues rather than in the internal region of the chain. Therefore, MCP-N and its degraded products might be developed to new potential galectin-3 inhibitors. This is the first report concerning the fractionation of MCP and its components on galectin-3 inhibition. The information provided in this paper is valuable for screening more active galectin-3 inhibitors from natural polysaccharides.

Topics: Animals; Cell Aggregation; Cells, Cultured; Chickens; Citrus; Galactans; Galectin 3; Glycoside Hydrolases; Pectins; Polysaccharides

Enzyme-resistant pectin or modified hairy regions were subjected to size exclusion (HPSEC) and weak anion exchange (WAX) chromatography. Fractions collected after separation were tested for the presence of different pectic epitopes using the monoclonal antibodies LM2, LM5, LM6, and JIM7. Separation by HPSEC showed that based on molecular weight the different epitopes were restricted to distinct molecular weight populations. WAX chromatography resulted in an even better separation of the different pectic epitopes present. A clear separation between arabino galactan type II epitopes and the RG I side chains, (1,5)-alpha-l-arabinan and (1,4)-beta-d-galactan, could be established. Arabinogalactan type II was found in the first populations eluting off the WAX column. The observations made within the ELISA assays of the collected fractions could be confirmed by determination of the sugar composition of the individual populations obtained. The sugar composition of the AGII positive populations eluting off the WAX column shows the presence of significant amounts of rhamnose and galacturonic acid. Together with the delay on an anion exchanger, this observation indicates a possible linkage between RGI and AGII. The volume of the individual fractions collected provides enough material for a maximum of 20 different antibodies to be tested from one analytical separation.

Topics: Antibodies, Monoclonal; Chromatography, High Pressure Liquid; Chromatography, Ion Exchange; Enzyme-Linked Immunosorbent Assay; Galactans; Hexuronic Acids; Pectins; Rhamnose

Border-like cells are released by Arabidopsis (Arabidopsis thaliana) root tips as organized layers of several cells that remain attached to each other rather than completely detached from each other, as is usually observed in border cells of many species. Unlike border cells, cell attachment between border-like cells is maintained after their release into the external environment. To investigate the role of cell wall polysaccharides in the attachment and organization of border-like cells, we have examined their release in several well-characterized mutants defective in the biosynthesis of xyloglucan, cellulose, or pectin. Our data show that among all mutants examined, only quasimodo mutants (qua1-1 and qua2-1), which have been characterized as producing less homogalacturonan, had an altered border-like cell phenotype as compared with the wild type. Border-like cells in both lines were released as isolated cells separated from each other, with the phenotype being much more pronounced in qua1-1 than in qua2-1. Further analysis of border-like cells in the qua1-1 mutant using immunocytochemistry and a set of anti-cell wall polysaccharide antibodies showed that the loss of the wild-type phenotype was accompanied by (1) a reduction in homogalacturonan-JIM5 epitope in the cell wall of border-like cells, confirmed by Fourier transform infrared microspectrometry, and (2) the secretion of an abundant mucilage that is enriched in xylogalacturonan and arabinogalactan-protein epitopes, in which the cells are trapped in the vicinity of the root tip.

Topics: Arabidopsis; Arabidopsis Proteins; Cell Wall; Galactans; Glucans; Hexosyltransferases; Hexuronic Acids; Immunohistochemistry; Mutation; Pectins; Phenotype; Plant Roots; Spectroscopy, Fourier Transform Infrared; Xylans

The callus culture of duckweed cultivated on medium containing different concentrations of beta-galactosidase was shown to produce the following polysaccharides: pectin lemnan LMC, intracellular AG1, and extracellular AG2 arabinogalactans. The samples of lemnan with 46% galactose residue reduction and 9-46% increased galacturonic acid residue content were obtained at beta-galactosidase concentrations of 10(-3)-10(-1)mg/mL. The most substantial alterations in the sugar composition of pectin were found to occur in the fraction with a molecular mass of 100-300 kDa. Low concentrations of enzyme failed to influence the sugar composition of intracellular arabinogalactan, whereas high concentrations were shown to decrease the amount of arabinose residues in AG1 and to cause galactan formation. Extracellular galactan was found to be produced on the medium with 10(-1) and 1mg/mL beta-galactosidase whereas extracellular arabinogalactan AG2 was shown to be biosynthesized without beta-galactosidase or at a beta-galactosidase concentration of 10(-3)mg/mL. Alterations in the sugar composition of polysaccharides were shown to be connected with the increasing activity of alpha-l-arabinofuranosidase and beta-galactosidase, and with the decreasing activity of intracellular polygalacturonase.

Topics: Araceae; beta-Galactosidase; Galactans; Glycoside Hydrolases; Pectins; Polygalacturonase; Polysaccharides

The distribution of several arabinogalactan protein and pectic epitopes were studied during organogenesis in androgenic callus of wheat. In cell wall of mature and degenerating parenchyma cells, the arabinogalactan epitopes JIM4, JIM14, JIM16 or LM2 were expressed differently according to the cells location. LM2 was observed also in meristematic cells of regenerated shoot buds and leaves. Anti-pectin JIM7 labelled the wall of meristematic cells but fluorescence was strongest in outer walls of surface cells of callus and shoot buds coated by extracellular matrix surface network (ECMSN). During leaves growth the ECMSN disappeared, and JIM7 fluorescence decreased. JIM5 epitope was abundant in the cell walls lining the intercellular spaces of callus parenchyma and in tricellular junctions within regenerated buds and leaves.

Topics: Culture Media; Epitopes; Galactans; Organogenesis; Pectins; Plant Leaves; Plant Shoots; Tissue Culture Techniques; Triticum

UV-C irradiation (254 nm) was found to enhance the secretion of some cell-wall-degrading enzymes, especially the following carbohydrases: beta-galactosidase, alpha-L-arabinofuranosidase, polygalacturonase, pectinesterase, cellulase, xylanase, and beta-xylosidase, in the campion callus, contributing thereby to an alteration in the polysaccharide structure. The relative amounts of the galactose and arabinose residues in pectin (silenan) and of arabinose in arabinogalactan of calli irradiated during the exponential phase were shown to decrease during the stationary phase. A decrease in the degree of SV methylesterification was found for the irradiated callus. These alterations were found to persist over a long period of culturing time. Decreasing the relative amounts of the arabinose residues in arabinogalactan and pectin and the galactose residues in silenan corresponded to increasing activity of alpha-L-arabinofuranosidase and beta-galactosidase, respectively, due to treatment with UV-C. UV-C irradiation may be used as a tool for modifying the structural features of the cell-wall polysaccharides, such as the relative amounts of galactose and arabinose residues in the side chains of polysaccharides, with the purpose of obtaining physiologically active polysaccharides with the desired properties and structural features.

Topics: Cell Wall; Enzyme Activation; Galactans; Glycoside Hydrolases; Pectins; Polysaccharides; Silene; Tissue Culture Techniques; Ultraviolet Rays

An immunomodulating pectic polymer, GOA1, obtained from the aerial parts of the Malian medicinal plant Glinus oppositifolius (L.) Aug. DC. (Aizoaceae) has previously been reported to consist of arabinogalactans type I and II, probably linked to a rhamnogalacturonan backbone. To further elucidate the structure of the polymer GOA1, enzymatic degradation studies and weak acid hydrolysis were performed. Five different glycosidases were used, endo-alpha-D-(1-->4)-polygalacturonase, exo-alpha-L-arabinofuranosidase, endo-alpha-L-(1-->5)-arabinanase, endo-beta-D-(1-->4)-galactanase and exo-beta-D-galactosidase. It appears that GOA1 may contain a structural moiety consisting of a 1,3-linked galactopyranosyl (Galp) main chain with 1,6-linked Galp side chains attached to position 6 of the main chain. The 1,6-linked Galp side chain may be branched in position 3 with arabinofuranosyl (Araf) side chains. A 1,4-linked Galp backbone which might carry side chains or glycosyl units attached to position 3 is also a structural element in the polymer. We further show that GOA1 induce proliferation of B cells and the secretion of IL-1beta by macrophages, in addition to a marked increase of mRNA for IFN-gamma in NK-cells. To elucidate structure-activity relations the native polymer and the digested fractions were tested for complement fixing activity and intestinal immune stimulating activity. The partial removal of Araf residues after enzymatic degradations did not affect the bioactivities, while the acid hydrolysed fraction showed reduced complement fixing activity. A decrease in Araf units, 1,3,6-linked Galp units and a partial hydrolysed rhamnogalacturonan backbone, in addition to a reduction in molecular weight are factors that might have contributed to reduced bioactivity.

Topics: Aizoaceae; Animals; Cell Line; Cell Line, Tumor; Cytokines; Dose-Response Relationship, Drug; Female; Galactans; Gene Expression; Humans; Hydrolysis; Immunologic Factors; Killer Cells, Natural; Macrophages; Magnetic Resonance Spectroscopy; Mice; Mice, Inbred C3H; Pectins; Peyer's Patches; Rats; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Polysaccharides (pectin and intracellular and extracellular arabinogalactans) were isolated from campion callus culture cultivated on medium with varied concentrations of pectinase and beta-galactosidase. A decrease in contents of arabinose residues in pectin and arabinogalactans and of galactose residues in arabinogalactans was associated with an increase in the activities of alpha-L-arabinofuranosidase and beta-galactosidase upon addition of pectinase into the medium. Pectinase destroyed the high-molecular-weight (more than 300 kD) fraction of pectin and decreased the content of galacturonic acid residues. alpha-L-Arabinofuranosidase transformed arabinogalactan into galactan, and galactan was destroyed under the influence of galactosidase. The contents of arabinogalactan and/or galactan in the cells were decreased, and it was released into the culture medium. Pectin samples with low contents of arabinose and galactose in the side chains and galactan samples were obtained from the callus grown on the medium with beta-galactosidase. Cultivation of the plant cells on medium containing carbohydrases resulted in modification of pectin and arabinogalactan of the cell walls.

Topics: Arabinose; beta-Galactosidase; Galactans; Glycoside Hydrolases; Hexuronic Acids; Pectins; Polygalacturonase; Polysaccharides; Silene

Structures of three pectic arabinogalactans, one from Vernonia kotschyana (Vk2a) and two from Cochlospermum tinctorium (Ct50A1 and Ct50A2), and their complement fixation and induction of B cell proliferation in vitro were compared. The polysaccharide Vk2a expressed potent biological activity in both assays compared with Ct50A1 and Ct50A2. Vk2a possessed a very high molecular weight (1150 +/- 20 kDa) compared with Ct50A1 and Ct50A2 which both showed a polydisperse nature with the highest molecular weight polymers in each fraction estimated at approximately 105 kDa (Ct1a) and 640 +/- 100 kDa (Ct2a), respectively. The HMW polymers showed complement fixation in the same range as the native fractions. The arabinogalactan II content was low in Vk2a (2%) compared with that in Ct50A1 (23%) and Ct50A2 (12%). The high molecular weight polymers were subjected to digestion with a beta-d-(1, 3)-galactanase-rich fraction from Driselase, oligomers were isolated by HPAEC, and their finer structures were determined by MALDI- and ES-qoToF-MS, linkage, and monosaccharide composition analyses. Vk2a consists of both a galacturonan core and a rhamnogalacturonan core rich in neutral side chains. The backbones of both Ct-polysaccharides consist mainly of RG-I regions with numerous neutral side chains dominated by galactosyl residues, whereas the homogalacturonan regions seem to be small. Differences in the chain lengths of the 6-linked galacto-oligosaccharides attached to the 3-linked galactan core could not be related to the differences in the potencies of the biological activities observed.

Topics: Amino Acids; Animals; Anti-Ulcer Agents; B-Lymphocytes; Bixaceae; Cells, Cultured; Complement Fixation Tests; Complement System Proteins; Female; Galactans; Glycosylation; Magnetic Resonance Spectroscopy; Mice; Mitogens; Mitosis; Molecular Weight; Monosaccharides; Oceans and Seas; Pectins; Structure-Activity Relationship; Vernonia

Arabinogalactan and pectin (named silenan) were isolated from Silene vulgaris (M.) G. callus. Fractionation by ion-exchange chromatography on DEAE-cellulose and digestion with pectinase demonstrated that silenan from S. vulgaris callus (80% of D-galacturonic acid) and silenan from the aerial part of the campion S. vulgaris are similar: both pectins contain a high quantity of homogalacturonan segments. The NMR spectral data and mass spectrometry of the purified polysaccharide and its fragment obtained by Smith degradation confirmed that the core of the arabinogalactan consisted of the different segments of beta-1,3-D-galactopyranan. Some of the beta-galactopyranose residues of the backbone are branched at O-6. The side chains of the arabinogalactan were shown to contain residues of terminal and 3-O-substituted beta-galactopyranose, terminal alpha-arabinofuranose and alpha-rhamnopyranose, and 2-O-substituted alpha-rhamnopyranose. The alpha-rhamnopyranose residues in the sugar chain appeared to be 2-O-glycosylated by the beta-1,4-D-galactopyranosyl uronic acid residues.

Topics: Amino Acid Sequence; Caryophyllaceae; Cell Fractionation; Galactans; Methylation; Nuclear Magnetic Resonance, Biomolecular; Pectins; Plant Proteins; Plant Tumors; Protein Denaturation

Two polysaccharides, a pectin (Vk100A2b) and a pectic arabinogalactan (Vk100A2a) with mean Mw 2 x 10(4) and 1.15 x 10(6)Da, respectively, were isolated from the dried powdered roots of Vernonia kotschyana Sch. Bip. ex Walp. by hot water extraction followed by fractionation on DEAE-Sepharose fast flow and Sephacryl S-400 HR. The pectin showed low-complement fixation activity and no influence on proliferation of B or T cells, while the pectic arabinogalactan showed a potent, dose-dependent complement fixation activity and a T cell independent induction of B-cell proliferation. Both polysaccharides induced chemotaxis of human macrophages, T cells and NK cells. exo-alpha-L-arabinofuranosidase and exo-beta-D-galactosidase digestion followed by component sugar and methylation analysis indicated that Vk100A2a consisted of a highly branched rhamnogalacturonan core with approximately 50% of the rhamnose 1,2,4-substituted, side chains rich in terminal-, 1,5-linked and 1,3,5-branched arabinose and terminal-, 1,4-, 1,6-linked and 1,3,6-branched galactose. The enzyme resistant part of Vk100A2a still showed strong complement fixating activity, suggesting that this activity may at least in part be expressed by carbohydrate structures present in the enzyme resistant, inner portion of the polymer.

Topics: Chemotaxis; Complement Fixation Tests; Complement System Proteins; Flow Cytometry; Galactans; Humans; Immunity; Macrophages; Nitric Oxide; Pectins; Plant Roots; T-Lymphocytes; Vernonia

Structure and immunological characteristics of the pectic arabinogalactan Vk2a (previously reported as Vk100A2a) from the roots of Vernonia kotschyana Sch. Bip. ex Walp. were investigated after enzymatic digestion of the galacturonan moiety and the side chains of the rhamnogalacturonan structure of Vk2a. endo-alpha-D-(1-->4)-Polygalacturonase digestion released the high molecular weight 'hairy region' (Vk2a-HR) and oligogalacturonides. Vk2a-HR consisted of GalA (4-linked) and Rha (2- or 2,4-linked) in a 1:1 ratio, with 60% of Rha branched at C-4. The Rha located in the rhamnogalacturonan core was branched randomly by Gal units. Vk2a-HR was rich in neutral sugars such as Araf 5- (12.2%) and 3,5-substituted (12.8%) and terminally- (14.1%) linked and Gal 4- (13.0%), 3- (0.9%), 6- (2.2%) and 3,6- (1.1%) substituted. Arabinans with chain lengths up to 11 units were identified. Araf residues were attached to C-3 of alpha-L-(1-->5)-Araf chains and to C-4 of Gal residues. Single Gal units and chains of beta-D-(1-->6)-linked galacto di- to penta-saccharides were attached to a beta-D-(1-->3)-galactan core. All the enzyme resistant fractions expressed potent complement fixation and induction of B-cell mitogenic activity, and the present study indicates that there may be several and possibly structurally different active sites involved in the bioactivity of Vk2a. The bioactive sites may be located both in the more peripheral parts of the molecule but also in the inner core of the 'hairy region' or in larger enzyme-resistant chains.

Topics: Animals; Binding Sites; Carbohydrate Conformation; Carbohydrates; Chromatography, Gel; Chromatography, High Pressure Liquid; Complement System Proteins; Erythrocytes; Galactans; Galactose; Gas Chromatography-Mass Spectrometry; Humans; Ions; Mass Spectrometry; Methylation; Mice; Mice, Inbred C3H; Mitogens; Oligosaccharides; Pectins; Plant Roots; Polysaccharides; Sheep; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Structure-Activity Relationship

A rhamnogalacturonan I polysaccharide was isolated from potato (Solanum tuberosum cv. Posmo) tuber cell walls and characterised by enzymatic digestion with an endo-beta-1 --> 4-galactanase and an endo-alpha-1 --> 5-arabinanase, individually or in combination. The reaction products were separated using size-exclusion chromatography and further analysed for monosaccharide composition and presence of epitopes using the LM5 anti-beta-1 --> 4-galactan and LM6 anti-alpha-1 --> 5-arabinan monoclonal antibodies. The analyses point to distinct structural features of potato tuber rhamnogalacturonan I, such as the abundance of beta-1 --> 4-galactan side chains that are poorly substituted with short arabinose-containing side chains, the presence of alpha-1 --> 5-arabinan side chains substituted with beta-1 --> 4-galactan oligomers (degree of polymerisation > 4), and the presence of alpha-1 --> 5-arabinans that resist enzymatic degradation. A synergy between the enzymes was observed towards the degradation of arabinans but not towards the degradation of galactans. The effect of the enzymes on isolated RG I is discussed in relation to documented effects of enzymes heterologously expressed in potato tubers. In addition, a novel and rapid method for the determination of the monosaccharide and uronic acid composition of cell wall polysaccharides using high-performance anion exchange chromatography with pulsed amperometric detection is described.

Topics: Cell Wall; Galactans; Pectins; Plant Roots; Solanum tuberosum

The cell wall composition of germinating pollen grains of Actinidia deliciosa was studied by immunolocalization with monoclonal antibodies against arabinogalactan proteins (AGPs) and pectins. In ungerminated pollen, the JIM8 epitope (against a subset of AGPs) was located in the intine and in the cytoplasm, while the MAC207 epitope (against AGPs) was located only in the exine. After germination, the JIM8 and MAC 207 epitopes were located in the cytoplasm and in the pollen tube wall. The Yariv reagent that binds to AGPs was added to the germination medium inducing a reduction or inhibition in pollen germination. This indicates that AGPs are present in the growing pollen tube and play an important role in pollen germination. To identify the nature of the pectins found in pollen grains and tubes, four monoclonal antibodies were used. The JIM5 epitope (against unesterifled pectins) was located in the intine, more intensely in the pore region, and along the pollen tube wall, and the JIM7 epitope (against methylesterified pectins) was also observed in the cytoplasm. After germination, the JIM5 epitope was located in the pollen tube wall; although, the tube tip was not labelled. The JIM7 epitope was located in the entire pollen tube wall. LM5 (against galactans) showed a labelling pattern similar to that of JIM5 and the pattern of LM6 (against arabinans) was similar to that of JIM7. Pectins show different distribution patterns when the degree of esterification is considered. Pollen tube wall pectins are less esterified than those of the pollen tube tip. The association of AGPs with pectins in the cell wall of the pollen grain and the pollen tube may play an important role in the maintenance of cell shape during pollen growth and development.

Topics: Actinidia; Antibodies, Monoclonal; Cell Wall; Galactans; Glycoproteins; Immunohistochemistry; Pectins; Pollen

A water-soluble acidic heteroglycan, DL-3Bb, isolated from the leaves of Diospyros kaki, had [alpha](D)(20) -19.9 degrees (c 0.30, water), and contained rhamnose, arabinose, xylose, galactose and galacturonic acid in the molar ratio of 1.0:4.5:0.7:1.5:1.0. About 44% of the galacturonic acid existed as its methyl ester, and O-acetyl groups (approx 5.7%) were also identified. Its molecular weight was determined to be 9.0x10(5) Da by high-performance gel-permeation chromatography. Its structural features were elucidated by a combination of methylation analysis, periodate oxidation, two steps of partial acid hydrolysis, and 1H and 13C NMR spectroscopy and ESI mass spectrometry. The data obtained indicated that DL-3Bb possessed a backbone of a disaccharide of [-->4)-alpha-GalAp-(1-->2)-alpha-Rhap-(1-->], with approx 58.7% substitution at O-4 of the rhamnopyranosyl residues by beta-(1-->4)-linked xylopyranosyl residues, and by beta-(1-->3) and beta-(1-->6)-linked galactopyranosyl (galactan) residues. The side chains were further substituted by arabinofuranosyl residues at O-2 by beta-(1-->4)-linked xylopyranosyl residues and at O-3 by beta-(1-->6)-linked galactopyranosyl residues. Preliminary tests in vitro revealed that it could stimulate LPS-induced B lymphocyte proliferation, but not for ConA-induced T lymphocyte proliferation. It was proposed that the acid-labile arabinofuranosyl residues in the side chains would not be needed for the expression of the enhancement of the immunological activity, and that the presence of GalAp in the backbone has an important, but not crucial effect on the expression of the activity.

Topics: Animals; Concanavalin A; Diospyros; Dose-Response Relationship, Drug; Galactans; Hydrolysis; Lipopolysaccharides; Lymphocyte Activation; Magnetic Resonance Spectroscopy; Methylation; Mice; Molecular Weight; Pectins; Plant Leaves; Polysaccharides; Spectrometry, Mass, Electrospray Ionization; Spleen

Crude polysaccharide fractions, rich mainly in arabinogalactans (A), pectin (B) and glucuronoxylan-related polymers (D), have been obtained from aerial parts of sage (Salvia officinalis L.) by sequential extraction with various reagents. Arabinogalactans displayed on HPLC a dominance of lower molecular-mass polymers (MW < 10,000), while pectin and glucuronoxylan-related polysaccharides showed predominance of polymers with MW > 50,000. Individual polysaccharide fractions were examined for their immunomodulatory activity in the in vitro comitogenic thymocyte test. The polysaccharide fractions tested possessed the capacity to induce rat thymocyte proliferation in the order D>B>A. Besides, fraction D possessed a significant comitogenic effect, and the SIcomit/SImit ratio 3-4 indicates potential adjuvant properties of this glucuronoxylan-rich material.

Topics: Adjuvants, Immunologic; Animals; Biochemistry; Cell Division; Cells, Cultured; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Dose-Response Relationship, Immunologic; Galactans; Magnetic Resonance Spectroscopy; Mitogens; Molecular Weight; Pectins; Polysaccharides; Rats; Rats, Wistar; Salvia officinalis; Spectroscopy, Fourier Transform Infrared; Thymus Gland; Xylans

Nonarticulated laticifers are latex-containing cells that elongate indefinitely and grow intrusively between the walls of meristematic cells. To identify biochemical mechanisms involved in the growth of nonarticulated laticifers, we have analyzed the distribution of various polysaccharides and proteoglycans in walls of meristematic cells in contact with laticifers, nonadjacent to laticifers, and in laticifer walls. In the shoot apex of Asclepias speciosa, the levels of callose and a (1-->4)-beta-galactan epitope are lower in meristematic walls in contact with laticifers than in nonadjacent walls. In contrast, we did not detect a decline in xyloglucan, homogalacturonan, and arabinogalactan-protein epitopes upon contact of meristematic cells with laticifers. Laticifer elongation is also associated with the development of a homogalacturonan-rich middle lamella between laticifers and their neighboring cells. Furthermore, laticifers lay down walls that differ from those of their surrounding cells. This is particularly evident for epitopes in rhamnogalacturonan I. A (1-->5)-alpha-arabinan epitope in this pectin is more abundant in laticifers than meristematic cells, while the opposite is observed for a (1-->4)-beta-galactan epitope. Also, different cell wall components exhibit distinct distribution patterns within laticifer walls. The (1-->5)-alpha-arabinan epitope is distributed throughout the laticifer walls while certain homogalacturonan and arabinogalactan-protein epitopes are preferentially located in particular regions of laticifer walls. Taken together, our results indicate that laticifer penetration causes changes in the walls of meristematic cells and that there are differences in wall composition within laticifer walls and between laticifers and their surrounding cells.

Topics: Apocynaceae; Galactans; Glucans; Immunohistochemistry; Meristem; Microscopy, Immunoelectron; Pectins; Seeds

Pectin termed silenan and acidic arabinogalactan were isolated as cell-wall polysaccharides of Silene vulgaris callus in the presence of various carbon sources as components of the media. The maximum yields, productivity per litre of medium and production per day of acidic arabinogalactan, were achieved using glucose or galactose as the carbon source. Sucrose was found to increase the production of the polysaccharides. Yields, productivity and rate of production of arabinogalactan per day were decreased in the presence of arabinose. Yields of silenan, productivity and rate of production per day were closely related irrespective of the sugar used as the carbon source in the media (sucrose, glucose or galactose) and yields of silenan from the callus growing on arabinose were comparable. A concentration of sucrose in the 20-50 g/L range enhanced the biosynthesis of silenan and at 50 g/L the silenan contained the linear backbone and the ramified regions of the macromolecule.

Topics: Carbon; Cell Wall; Galactans; Oligosaccharides; Pectins; Silene

In Silene vulgaris (M.) G. cell culture three growth phases were distinguished, namely, a lag phase, an exponential phase and a stationary phase. Pectin termed silenan and an acidic arabinogalactan were isolated as cell wall polysaccharides of S. vulgaris callus at the different growth phases during culture. Production of silenan as the galacturonan (or rhamnogalacturonan) core was observed at the beginning of the exponential phase and at the stationary phase of the callus growth. Arabinogalactan, containing the galacturonic acid residues, is formed at the exponential phase followed by attachment to the core of silenan in the middle of the exponential phase. The arabinogalactan constituent of silenan appeared to be destroyed gradually at the stationary growth phase. The monosaccharide compositions of silenan and arabinogalactan were determined at various phases of the callus growth. Silenan was found to be formed in maximum amounts at the exponential phase of the cell growth. Insignificant alterations of the yields of acidic arabinogalactan were found during culture while total productivity per litre of medium and rate of production per day of arabinogalactan were found to be maximal at the exponential phase of growth.

Topics: Cell Wall; Culture Techniques; Galactans; Pectins; Polysaccharides; Silene

The composition of guard cell walls in sugar beet leaves (Beta vulgaris L.) was studied by using histochemical staining and immunocytochemical detection of cell wall antigens. The findings were compared with those in the walls of epidermal and mesophyll cells. Probing of leaf sections with monoclonal antibodies against pectins, terminal fucosyl residues linked alpha-(1-->2) to galactose, beta-(1-->3)-glucans and arabinogalactan-proteins revealed several specific features of guard cells. Pectic epitopes recognized by JIM7 were homogeneously distributed in the wall, whereas pectins recognized by JIM5 were not found in the walls themselves, but were abundant in the cuticular layer. Large amounts of molecules bearing terminal fucose were located predominantly in ventral and lateral guard cell walls. Much smaller amounts were detected in dorsal walls of these cells, as well as in the walls of pavement and mesophyll cells. Conspicuous accumulation of these compounds was observed in the vicinity of the guard cell plasmalemma, whereas labelling was scarce in the areas of the wall adjacent to the cell surface. The presence of callose clearly marked the ventral wall between the recently formed, very young guard cells. Callose also appeared in some mature walls, where it was seen as punctate deposits that probably reflected a specific physiological state of the guard cells. Large amounts of arabinogalactan-proteins were deposited within the cuticle, and smaller amounts of these proteoglycans were also detected in other tissues of the leaf. The histochemical and immunocytochemical structure of the guard cell wall is discussed in the light of its multiple functions, most of which involve changes in cell size and shape.

Topics: Antibodies, Monoclonal; Beta vulgaris; Cell Differentiation; Cell Wall; Epitopes; Fucose; Galactans; Glucans; Immunohistochemistry; Microscopy, Electron; Pectins; Plant Structures; Polysaccharides; Xylans

CDTA-extractable soybean pectic substances were subjected to enzymatic digestion with arabinogalactan degrading enzymes yielding a resistant polymeric pectic backbone and arabino-, galacto-, and arabinogalacto-oligomers. The complex digest was fractionated using size-exclusion chromatography. Monosaccharide composition analysis, HPAEC fractionation and MALDI-TOF MS analysis of the resulting fractions showed that each contained a mixture of oligosaccharides of essentially the same degree of polymerisation, composed of only arabinose and galactose. MALDI-TOF MS analysis was used for molecular mass screening of oligosaccharides in underivatised HPAEC fractions. The monosaccharide sequence and the branching pattern of oligosaccharides (degree of polymerisation from 4 to 8) were determined using linkage analysis and ES-CID tandem MS analysis of the per-O-methylated oligosaccharides in each of the HPAEC fractions. These analyses indicated the presence of common linear (1 --> 4)-linked galacto-oligosaccharides, and both linear and branched arabino-oligosaccharides. In addition, the results unambiguously showed the presence of oligosaccharides containing (1 --> 4)-linked galactose residues bearing an arabinopyranose residue as the non-reducing terminal residue, and a mixture of linear oligosaccharides constructed of (1 --> 4)-linked galactose residues interspersed with an internal (1 --> 5)-linked arabinofuranose residue. The consequences of these two new structural features of pectic arabinogalactan side chains are discussed.

Topics: Arabinose; Carbohydrate Conformation; Chelating Agents; Chromatography, Gel; Edetic Acid; Galactans; Glycine max; Glycoside Hydrolases; Models, Molecular; Oligosaccharides; Pectins; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Monoclonal antibody CCRC-M7 is representative of a group of antibodies with similar binding specificity that were generated using the plant cell-wall pectic polysaccharide, rhamnogalacturonan I, as immunogen. The epitope recognized by CCRC-M7 is present in several plant polysaccharides and membrane glycoproteins. Selective enzymatic or chemical removal of arabinosyl residues from rhamnogalacturonan I reduced, but did not abolish, the ability of CCRC-M7 to bind to the polysaccharide. In contrast, enzymatic removal of both arabinosyl and galactosyl residues from rhamnogalacturonan I completely abolished binding of CCRC-M7 to the resulting polysaccharide. Competitive ELISAs using chemically defined oligosaccharides to compete for the CCRC-M7 binding site showed that oligosaccharides containing (1-->6)-linked beta-D-galactosyl residues were the best competitors among those tested, with the tri-, penta-, and hexa-saccharides being equally effective. The combined results from indirect and competitive ELISAs suggest that the minimal epitope recognized by CCRC-M7 encompasses a (1-->6)-linked beta-galactan containing at least three galactosyl residues with at least one arabinosyl residue attached.

Topics: Antibodies, Monoclonal; Binding Sites, Antibody; Binding, Competitive; Cell Wall; Cells, Cultured; Chromatography, High Pressure Liquid; Enzyme-Linked Immunosorbent Assay; Epitopes; Galactans; Hydrolysis; Molecular Structure; Pectins; Plants

Fusarium oxysporum f. sp. vasinfectum penetration hyphae infect living cells in the meristematic zone of cotton (Gossypium barbadense L.) roots. We characterized wall modifications induced by the fungus during infection of the protodermis using antibodies against callose, arabinogalactan-proteins, xyloglucan, pectin, polygalacturonic acid and rhamnogalacturonan I in high-pressure frozen, freeze-substituted root tissue. Using quantitative immunogold labelling we compared the cell walls before and after hyphal contact, cell plates with plasmodesmata during cytokinesis, and wall appositions induced by fungal contact. In the already-existing wall, fungal contact induced only minor modifications such as an increase of xyloglucan epitopes. Wall appositions mostly exhibited epitopes similar to the cell plate except that wall appositions had a much higher callose content. This study shows that wall appositions induced by Fusarium oxysporum hyphae are the result of normal cell wall synthesis and the addition of large amounts of callose. The appositions do not stop fungal growth.

Topics: Cell Wall; Fusarium; Galactans; Glucans; Gossypium; Pectins; Plant Diseases; Plant Roots; Polysaccharides; Xylans

An in vitro faecal incubation system was used to study the metabolism of complex carbohydrates by intestinal bacteria. Homogenates of human faeces were incubated anaerobically with added lactulose, pectin, the hemicellulose arabinogalactan, and cellulose, both before and after subjects had been pre-fed each carbohydrate. Fermentation of added substrate was assessed by the production of short-chain fatty acids (SCFA) and suppression of net ammonia generation over 48 h of incubation. Control faecal homogenates to which carbohydrate was not added yielded an average increment of SCFA of 43 mmol/l, equivalent to 172 mmol/kg in the original stool. The addition of lactulose, pectin and arabinogalactan each increased the yield of SCFA by a similar amount, averaging 6.5 mmol/g carbohydrate or 1.05 mol/mol hexose equivalent; organic acid yield was not increased by pre-feeding these substances for up to 2 weeks. Acetate was the major SCFA in all samples at all times and, after pre-feeding with extra carbohydrate, butyrate concentrations exceeded propionate in all samples. Faecal homogenates incubated with cellulose showed no greater SCFA production than controls over the first 48 h, but there was a slight increase when samples from two subjects pre-fed cellulose were incubated for 14 d. Net ammonia generation was markedly suppressed by addition of lactulose to faecal incubates with an initial period of net bacterial uptake of ammonia. Pectin and arabinogalactan also decreased ammonia generation, but the reductions were not significant unless subjects were pre-fed these materials; cellulose had no effect on ammonia generation.

Topics: Adult; Ammonia; Cellulose; Dietary Carbohydrates; Fatty Acids, Volatile; Feces; Galactans; Humans; Hydrogen-Ion Concentration; Lactulose; Middle Aged; Osmolar Concentration; Pectins

Organisms able to grow on arabinogalactan, pectin, xylan, wheat bran, guar, apple cell walls, and mucin were isolated by enrichment from human feces. The number of polysaccharide fermenters and the properties of the predominant bacteria varied between subjects. The ability to use one polysaccharide was not related to the ability to use others. Some organisms (e.g., Bacteroides spp.) isolated on other substrates also utilized mucin, but were not isolated in the mucin enrichment. The mucin fermenters isolated by enrichment had a very restricted ability to utilize complex polysaccharides and their constituent monosaccharides, suggesting that the presence of plant polysaccharides in the human colon is unlikely to prevent the use of colonic mucin as an energy source by bacteria. Characterization with a range of biochemical tests showed that many of the isolates, but especially the mucin fermenters, did not resemble organisms described previously.

Topics: Bacteria, Anaerobic; Dietary Fiber; Feces; Fermentation; Galactans; Humans; Mannans; Mucins; Pectins; Plant Gums; Polysaccharides; Xylans