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Siberian larch wood (Larix sibirica Lebed.) contains such valuable biologically active substances as dihydroquercetin (DHQ) and arabinogalactan (AG), promising for the use in the pharmaceutical and food industries. An urgent task is to improve the methods of extraction isolation of these compounds from wood. In this work, we studied the possibility of simultaneous isolation of dihydroquercetin and arabinogalactan by extraction of larch wood with 5–25% aqueous ethanol solutions. It has been shown that by extracting wood with aqueous solutions with a low concentration of ethanol, it is possible to exclude the stage of separation of resinous substances from the target products of DHQ and AG. By experimentally optimizing of water-ethanol extraction process, it was shown that the highest yields of DHQ (1.8% mas.) and AG (18.0% mas.) were achieved by extraction of larch wood, crushed to particles of 1–3 mm in size, with a 15% ethanol solution for 2 hours. That the preliminarily mechanical treatment of larch wood allows to reduce the time of water-alcohol extraction to 30 minutes and to obtain DHQ and AG with high yields. The structure of DHQ and AG was confirmed by FTIR and NMR spectroscopy. Identification and purity of DHQ isolated from larch wood were confirmed by a photometric method using the reaction of cyanidin chloride formation when DHQ in heated in ethanol in the presence of hydrochloric acid., Древесина лиственницы сибирской (Larix sibirica Lebed.) содержит такие ценные биологически активные вещества, как флавоноид дигидрокверцетин (ДКВ) и полисахарид арабиногалактан (АГ), перспективные для использования в фармацевтической и пищевой промышленности. Актуальной задачей является совершенствование методов экстракционного извлечения этих соединений из древесины лиственницы. В данной работе изучена возможность одновременного извлечения дигидрокверцетина и арабиногалактана путем экстракции древесины лиственницы 5–25% водными растворами этанола. Показано, что экстракция древесины водными растворами с невысокой концентрацией этанола позволяет исключить стадию отделения смолистых веществ от целевых продуктов ДКВ и АГ. Путем экспериментальной оптимизации процесса водно-этанольной экстракции установлено, что наиболее высокий выход ДКВ (до 1.8%) и АГ (до 18.0%) достигается при экстракции древесины лиственницы, измельченной до частиц размером 1–3 мм, 15% раствором этанола в течение 2 ч. Показано, что предварительная механоактивация древесины лиственницы позволяет сократить продолжительность водно-спиртовой экстракции до 30 мин и получить ДКВ и АГ с высоким выходом. Строение ДКВ и АГ подтверждено методами ИК- и ЯМР-спектроскопии. Идентификация и чистота выделенного из древесины лиственницы ДКВ подтверждена фотометрическим методом с использованием реакции образования цианидинхлорида при нагревании ДКВ в этаноле в присутствии соляной кислоты.

In the present study, a water-soluble neutral polysaccharide (CAPW-1) with an average molecular weight of 64 kDa was purified from the root of Cynanchum atratum Bunge (Apocynaceae). The monosaccharide residue analysis revealed that CAPW-1 was composed of arabinose and galactose with a relative molar ratio of 7: 3. The backbone of CAPW-1 was consisted of 1,3-Galp and 1,3,6-Galp, the branches were attached to the O-6 of 1,3-Galp, and the side chains contained 1,6-Galp, 1,3,6-Galp, 1,5-linked, 1,3-linked, 1,3,5-linked, and terminal-Araf, which was attached to the O-3 of side 1,6-Galp. The bioactivity study indicated CAPW-1 could stimulate the proliferation of RAW264.7 cells and promote the secretion of nitric oxide (NO), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) with no cytotoxicity. The results suggested a potential application of CAPW-1 as an immunostimulant for the treatment of diseases such as infection and tumor.

Mycobacteria, which cause tuberculosis and related diseases, possess a diverse set of complex envelope lipids that provide remarkable tolerance to antibiotics and are major virulence factors that drive pathogenesis. Recently, metabolic labeling and bio-orthogonal chemistry have been harnessed to develop chemical probes for tagging specific lipids in live mycobacteria, enabling a range of new basic and translational research avenues. A toolbox of probes has been developed for labeling mycolic acids and their derivatives, including trehalose-, arabinogalactan-, and protein-linked mycolates, as well as newer probes for labeling phthiocerol dimycocerosates (PDIMs) and potentially other envelope lipids. These lipid-centric tools have yielded fresh insights into mycobacterial growth and host interactions, provided new avenues for drug target discovery and characterization, and inspired innovative diagnostic and therapeutic strategies.

Arabinogalactan-proteins (AGPs) are complex, hyperglycosylated plant cell wall proteins with little known about the biological roles of their glycan moieties in sexual reproduction. Here, we report that GLCAT14A, GLCAT14B and GLCAT14C, three enzymes responsible for the addition of glucuronic acid residues to AGPs, function in pollen development, polytubey block, and normal embryo development in Arabidopsis. Using biochemical and immunolabelling techniques, we demonstrated that the loss of function of the GLCAT14A, GLCAT14B and GLCAT14C genes resulted in disorganization of the reticulate structure of the exine wall, abnormal development of the intine layer, and collapse of pollen grains in glcat14a/b and glcat14a/b/c mutants. Synchronous development between locules within the same anther was also lost in some glcat14a/b/c stamens. In addition, we observed excessive attraction of pollen tubes targeting glcat14a/b/c ovules, indicating that the polytubey block mechanism was compromised. Monosaccharide composition analysis revealed significant reductions in all sugars in glcat14a/b and glcat14a/b/c mutants except for arabinose and galactose, while immunolabeling showed decreased amounts of AGP sugar epitopes recognized by glcat14a/b and glcat14a/b/c mutants compared to wild type. This work demonstrates the important roles that AG glucuronidation plays in Arabidopsis sexual reproduction and reproductive development. Supporting Information.

The article considers the possibility of expanding the range of fermented milk products enriched with natural sources of biologically active substances, which is an urgent task today, as it corresponds to the concept of state policy of the Russian Federation in the field of healthy nutrition. As a solution to this problem, it has proposed to enrich the curd mass as part of the daily diet. Promising plant raw materials of the Far Eastern region, such as Ahnfeltia tobuchinensis, a representative of the genus of red algae growing in the Far Eastern Seas, are used as functional and enriching ingredients; Dahurian larch wood extract – arabinogalactan (Lavitol-arabinogalactan) and peppermint (Méntha piperíta). Grounded ahnfeltia was used in the size of not more than 0,5 mm. On the basis of the analysis of the composition and properties of the applied non-traditional additives, the possibility of enrichment of curd products with dietary fiber and organic iodine from plant components has been substantiated. Optimal ratios of enriching prescription components to the weight of cottage cheese in a finished product are the following: ahnfeltia powder – 1,5%, arabinogalactan – 2,5%, peppermint – 1%. Also, when determining the optimal dosages of the introduced components, it is proposed to replace the prescription amount of sugar with flower honey, which is a natural sweetener and a powerful antioxidant. Organoleptic and physicochemical parameters of the finished samples have been analyzed. As a result of the research the functional curd product one portion (100 g) of which is capable to satisfy daily physiological need of an organism for iodine for 29,32%, in dietary fibers for 12,38% has been developed.

The present study explored the effects of combination of Tinospora cordifolia and Arabinogalactan on surface membrane dynamics and programmed cell deaths in rat model of lung cancer. The rats were divided into different groups namely normal control, benzo(a)pyrene (BP) treated, BP + Tinospora cordifolia (TC)-treated, BP + Arabinogalactan (A)-treated and BP + TC + A-treated groups. Significant changes were observed in the membrane dynamics of rats treated with BP. The carcinogen treatment demonstrated a marked decrease in membrane microviscosity. Also, excimer/monomer ratio and fluidity parameters of BP treated rats showed significant rise. On the other hand, combination of Tinospora cordifolia and Arabinogalactan improvised surface membrane dynamics. Moreover, micronuclei formation along with protein expression of bcl-2 showed significant increase in the lungs of BP treated rats. The combined treatment of Tinospora cordifolia and Arabinogalactan moderated the micronuclei formation in BP treated rats. Also, the combined treatment regulated the protein expressions of bcl-2 in BP-treated rats. As a result, marked improvement was noticed in apoptosis of BP treated cells treated with combination treatment. This study concludes that the Tinospora cordifolia and Arabinogalactan in combination improve the surface membrane dynamics and apoptosis in BP-treated rats.

Biodegradable compositions based on low-density polyethylene and polylactide containing arabinogalactan are obtained. Their mechanical properties are studied. It is shown that the development of absorbents based on arabinogalactan is complicated by specific features of the structure of its macromolecules, and possible methods of for overcoming them are considered.

Macromolecular structure of iron-containing bionanocomposites based on natural polysaccharide arabinogalactan has been studied. Also, the magnetic properties of Fe3O4 nanoparticles stabilized by the arabinogalactan matrix for biomedical applications have been evaluated. The electron paramagnetic resonance broad line, attributable to the core of Fe3O4 nanoparticles, shows some anisotropy, this signal being broadened with decreasing temperature. The dependence of the spectral characteristics (such as $g$ -factor, linewidth, and anisotropy), coercive field, and remanence magnetization of nanocomposites on the size of magnetite nanoparticles is presented. The effects of the novel bionanocomposite on erythrocyte systems in experimental anemia, as well as the iron-stabilizing effect, correction of iron deficiency, and relief of the manifestations of iron deficiency anemia, are analyzed.

The valuable cannabinoid and terpenoid metabolites of Cannabis sativa L. are produced by floral glandular trichomes. The trichomes consist of secretory disk cells, which produce the abundant lipidic metabolites, and an extracellular storage cavity. The mechanisms of apoplastic cavity formation to accumulate and store metabolites in cannabis glandular trichomes remain wholly unexplored. Here, we identify key wall components and how they change during cannabis trichome development. While glycome and monosaccharide analyses revealed that glandular trichomes have loosely bound xyloglucans and pectic polysaccharides, quantitative immunolabeling with wall-directed antibodies revealed precise spatiotemporal distributions of cell wall epitopes. An epidermal-like identity of early trichome walls matured into specialized wall domains over development. Cavity biogenesis was marked by separation of the subcuticular wall from the underlying surface wall in a homogalacturonan and α-1,5 arabinan epitope-rich zone and was associated with a reduction in fucosylated xyloglucan epitopes. As the cavity filled, a matrix with arabinogalactan and α-1,5 arabinan epitopes enclosed the metabolite droplets. At maturity, the disk cells’ apical wall facing the storage cavity accumulated rhamnogalacturonan-I epitopes near the plasma membrane. Together, these data indicate that cannabis glandular trichomes undergo spatiotemporal remodeling at specific wall subdomains to facilitate storage cavity formation and metabolite storage.

International audience; Adsorption of five different hyperbranched arabinogalactan-protein (AGP) fractions from Acacia senegal gum was thoroughly studied at the solid-liquid interface using a quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasmon resonance (SPR), and atomic force microscopy (AFM). The impact of the protein/sugar ratio, molecular weight, and aggregation state on the adsorption capacity was investigated by studying AGP fractions with different structural and biochemical features. Adsorption on a solid surface would be primarily driven by the protein moiety of the AGPs through hydrophobic forces and electrostatic interactions. Increasing ionic strength allows the decrease in electrostatic repulsions and, therefore, the formation of high-coverage films with aggregates on the surface. However, the maximum adsorption capacity was not reached by fractions with a higher protein content but by a fraction that contains an average protein quantity and presents a high content of high-molecular-weight AGPs. The results of this thorough study highlighted that the AGP surface adsorption process would depend not only on the protein moiety and high-molecular-weight AGP content but also on other parameters such as the structural accessibility of proteins, the molecular weight distribution, and the AGP flexibility, allowing structural rearrangements on the surface and spreading to form a viscoelastic film

1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) is widely used as a crosslinker for fluorescence labeling of protein in the fields of biochemistry and food analysis. Many natural polysaccharides often contain some proteins or peptides that are very low in content but play a vital role in their biological function as well as technical applications. Determination of these low-content proteinaceous matters requires a highly sensitive and selective method. In this study, a methodological approach for investigations of the presence of proteinaceous material over the molar mass distribution (MD) of polysaccharides was developed using gum acacia (GA) as a model polysaccharide. EDC fluorescence-labeling method was modified by changing the pH (7, 9, and 11) of the solution for the analysis of low-content protein in food materials. Fluorescence spectroscopy and asymmetrical flow field-flow fractionation (AF4) were employed for characterizing the labeling efficiency and physiochemical properties of unlabeled and fluorescence-labeled GA. AF4 provided molar mass (M) and the radius of gyration (rG) of arabinogalactan (AG) and arabinogalactan protein complex (AGP) and determined the presence of proteinaceous matter over the MD. The labeling efficiencies of GA at pH 7, 9, and 11 determined by fluorescence spectroscopy were 56.5, 68.4, and 72.0%, respectively, with an increment of 15.5% when pH was increased from 7 to 11. The modified EDC fluorescence-labeling method allows highly sensitive and selective analysis of low-content proteinaceous matters and their distribution in natural polysaccharides. Graphical abstract

Haloalkane dehalogenase DhaA can catalyze the hydrolytic cleavage of carbonhalogen bonds, along with production of the corresponding alcohol, a proton and a halide. However, DhaA suffers from poor environmental tolerance, such as sensitivity to high temperature, low pH and hypersaline. Arabinogalactan (AG) is a hydrophilic polysaccharide with highly branched long chains. DhaA was conjugated with AG to improve the environmental stability of DhaA in the present study. Each DhaA was averagely conjugated with 4∼5 AG molecules. Conjugation of AG essentially maintained the enzymatic activity of DhaA (91.4 %) without apparent structural alteration. The hydration layer formed by AG could reduce the solvent accessible area of DhaA and slow the protonation process, thereby improving the pH and high salt stability of DhaA. In particular, the remaining activities of the conjugate (AG-DhaA) were 35.3 % after treatment at pH4.0 for 1 h, and 80.8 % in 1 M NaCl after treatment for 16 h. As compared with DhaA, AG-DhaA showed slightly different kinetic parameters (K M of 1.90 μmol/L and k cat of 2.60 s -1).

Root cap-derived cells and mucilage provide the first line of defense of the plant against soil microbial pathogens. These cells form a mucilaginous root extracellular trap (RET), which also harbors a range of molecules including exDNA and defensive peptides and proteins much like the neutrophil extracellular trap (NET) of mammalians. Plant RETs resemble mucus structures found in mammalian systems and are rich in arabinogalactan proteins that have similarities to highly glycosylated human mucins. Human mucus and mucins regulate the intestinal flora microbiome through recruiting certain species of microbes and it is plausible that the arabinogalactan protein-rich mucilage found in plant roots fulfills a similar function by attracting specific microbes to the rhizosphere. The role of RETs in root defense functioning is highlighted.

Orevac–crumb rubber–arabinogalactan composites of different composition are obtained under the action of shear deformations in a Brabender mixer. The structure, mechanical properties, and biodegradability of the materials are studied. It is shown that an increase in arabinogalactan content leads to increase in elastic modulus and decrease in elongation at break, as well as slightly affecting the tensile strength. The mass loss of the samples after exposure in soil defining their biodegradability rises with an increase in arabinogalactan content in the composites.

Water-soluble polysaccharides (WSPS), pectinic substances, and hemicelluloses were isolated from the aerial part of Ferula tenuisecta. Their physicochemical parameters were characterized. The monosaccharide composition was established. Fractionation of the WSPS produced the arabinogalactan AG-Ften. Periodate oxidation and methylation established that the polysaccharide was an arabino-3,6-galactan.

An analysis of the acute and subacute toxicity of a copper oxide nanocomposite (NC) encapsulated in natural polymeric matrix of arabinogalactan is presented. The study was carried out in two stages. At the first stage, the acute toxicity of the NC was studied. For this, white mice were orally administered one time with an aqueous solution of NC at a dose 2000 mg/kg. The study demonstrated that according to this parameter, NC belongs to low-toxicity substances of hazard class 5. At the second stage, the biological response of the white rats was evaluated with a subacute intragastric effect of Cu2ОAG NC at a dose of 500 µg/kg (based on Cu) body weight within 10 days. The study demonstrated an increase in the contents of copper in the brain tissue, liver, and kidneys compared with the control group. Morphological and neurophysiological changes were detected in white rats treated with this NC. A pronounced macrophage reaction consisting in an increase in the number of Kupffer cells in the organ sinusoids was observed in liver tissue. In the tissues of the sensorimotor cortex of the brain, a sharp decrease in the number of astroglia cells was detected, which indicates a selective cytotoxicity of this NC. When studying the bioelectric activity of the sensorimotor cortex of the brain in animals a decrease in β-2 rhythm of background electroencephalogram, as well as a decrease in the amplitude of the P2 and N2-P3 peaks of the visually evoked potentials, were observed. No genotoxic effects were detected under the influence of the NC.

Herpes simplex virus type 1(HSV-1) attaches to cell surface heparan sulfate aiming to enter into susceptible cells. In this work, we utilized a sulfur trioxide-pyridine in N,N-dimethylformamide (SO3·Pyr/DMF) based amalgamated extraction-sulfation procedure for producing arabinogalactan sulfates from Anogeissus latifolia gum. Chemical, chromatographic, spectroscopic and chemical data revealed that the derived polymers contained varying molecular masses (31–69 kDa) and degrees of sulfation (0.1–0.5), but similar saccharide compositions. The highly active polymer (HSV-1: IC50 and SI, respectively, of 127 μg/mL and 15.7) was a 69 kDa arabinogalactan holding sulfates at O-5 of arabinofuranosyl residues and showed no cytotoxicity as far as 2 mg/mL concentration. This chemically sulfated macromolecule acted by obstructing viral attachment and entry. Thus, SO3·Pyr/DMF is suitable for producing new molecules with varied structures and altered pharmacological activities from plant sources.

Water-soluble nanocomposites consisting of arabinogalactan (AG)-stabilized Bi2Te3 nanoparticles with an average size of 32–44 nm were synthesized for the first time on the basis of the natural polysaccharide arabinogalactan and telluride ions generated from elemental tellurium in the system N2H4·H2O–KOH. The phase composition, morphology, and average size of Bi2Te3 nanoparticles were found to be determined by the conditions of their synthesis. Increase of the ratio AG/Bi3+/Te2– is accompanied by reduction of the degree of sphericity and increase of the average size of Bi2Te3 nanoparticles, as well as by the transition of the AG/Bi2Te3 nanocomposite from amorphous to amorphous–crystalline state.

The purpose of the research is studying the influence of various components on the targeted delivery of fenbendazole and evaluation of their efficacy in mice experimentally infected with Trichinella spiralis.Materials and methods. The experiment used 80 white mice experimentally infected with T. spiralis, at a dose of 200 larvae per animal. Each group of 10 animals was administered intragastrically solid dispersion of fenbendazole (SDF) with polyvinyl pyrrolidone (PVP), arabinogalactan (AG), disodium salt of glycyrrhizinic acid (Na2 GA), sodium dioctyl sulfosuccinate (SDS), licorice extract (LE) and hydroxyethyl starch (HES) at a single dose of 2.0 mg/kg of active substance as compared with the fenbendazole substance at the same dose. The control group did not receive the drug. The anthelmintic efficacy was studied by the results of necropsy of the small intestine of mice on the second day after drugs administration. The concentration of fenbendazole and its metabolites in the small intestine was determined by high-performance liquid chromatography with tandem mass spectrometry detection.Results and discussion. SDF with PVP, AG, Na2 GA, SDS, LE and HES showed 98.0, 94.9, 96.6, 100, 86.0 and 81.0% efficacy against intestinal nematode T. spiralis at a dose of 2.0 mg/kg of AS (fenbendazole). The maximum concentration of fenbendazole and its metabolites – sulfone and sulfoxide - was determined in the small intestine wall of animals on the second day after SDF with SDS administration and amounted to 3117.8, 614.6 and 2998.6 ng/g respectively. After fenbendazole substance administration, the drug and its metabolites were found in trace quantity.

Synthesis, structural features, and paramagnetic properties of manganese-containing nanocomposites based on polysaccharides arabinogalactan, sulfated arabinogalactan, and κ-carrageenan have been st...

The nanoscale 20-hydroxyecdysone was first proposed and obtained in the form of a clathrate complex with arabinogalactan with an average particle size of 35,3 nm. The study of its acute toxicity has revealed that the product belongs to class VI of relatively harmless drugs according to Hodge and to class 5th in accordance with GOST 32644-2014.

Pistil AGPs display dynamic localization patterns in response to fertilization in tomato. SlyFLA9 (Solyc07g065540.1) is a chimeric Fasciclin-like AGP with enriched expression in the ovary, suggesting a potential function during pollen–pistil interaction. During fertilization, the male gametes are delivered by pollen tubes to receptive ovules, deeply embedded in the sporophytic tissues of the pistil. Arabinogalactan glycoproteins (AGPs) are a diverse family of highly glycosylated, secreted proteins which have been widely implicated in plant reproduction, particularly within the pistil. Though tomato (Solanum lycopersicum) is an important crop requiring successful fertilization for production, the molecular basis of this event remains understudied. Here we explore the spatiotemporal localization of AGPs in the mature tomato pistil before and after fertilization. Using histological techniques to detect AGP sugar moieties, we found that accumulation of AGPs correlated with the maturation of the stigma and we identified an AGP subpopulation restricted to the micropyle that was no longer visible upon fertilization. To identify candidate pistil AGP genes, we used an RNA-sequencing approach to catalog gene expression in functionally distinct subsections of the mature tomato pistil (the stigma, apical and basal style and ovary) as well as pollen and pollen tubes. Of 161 predicted AGP and AGP-like proteins encoded in the tomato genome, we identified four genes with specifically enriched expression in reproductive tissues. We further validated expression of two of these, a Fasciclin-like AGP (SlyFLA9, Solyc07g065540.1) and a novel hybrid AGP (SlyHAE, Solyc09g075580.1). Using in situ hybridization, we also found SlyFLA9 was expressed in the integuments of the ovule and the pericarp. Additionally, differential expression analyses of the pistil transcriptome revealed previously unreported genes with enriched expression in each subsection of the mature pistil, setting the foundation for future functional studies.

Stinging nettle is a perennial herbaceous species holding value as a multi-purpose plant. Indeed, its leaves and roots are phytofactories providing functional ingredients of medicinal interest and its stems produce silky and resistant extraxylary fibers (a.k.a. bast fibers) valued in the biocomposite sector. Similarly to what is reported in other fiber crops, the stem of nettle contains both lignified and hypolignified fibers in the core and cortex, respectively, and it is therefore a useful model for cell wall research. Indeed, data on nettle stem tissues can be compared to those obtained in other models, such as hemp and flax, to support hypotheses on the differentiation and development of bast fibers. The suitability of the nettle stem as model for cell wall-related research was already validated using a transcriptomics and biochemical approach focused on internodes at different developmental stages sampled at the top, middle, and bottom of the stem. We here sought to complement and enrich these data by providing immunohistochemical and ultrastructural details on young and older stem internodes. Antibodies recognizing non-cellulosic polysaccharides (galactans, arabinans, rhamnogalacturonans) and arabinogalactan proteins were here investigated with the goal of understanding whether their distribution changes in the stem tissues in relation to the bast fiber and vascular tissue development. The results obtained indicate that the occurrence and distribution of cell wall polysaccharides and proteins differ between young and older internodes and that these changes are particularly evident in the bast fibers. Supplementary Information The online version contains supplementary material available at 10.1007/s00709-021-01641-1.

The article studied the structural features of solid dispersions of pinostrobin oxime with arabinogalactan, disodium salt of glycyrrhizic acid, polyvinylpyrrolidone and basic magnesium carbonate obtained by mechanochemical treatment. The obtained complexes of pinostrobin oxime with arabinogalactan, disodium salt of glycyrrhizic acid, polyvinylpyrrolidone, and basic magnesium carbonate have increased water solubility in comparison with the initial pinostrobin oxime. The thermal effects of pinostrobin oxime and its complex compounds have been studied by differential scanning calorimetry. At the same time, on the DSC-curve, the melting peak of solid dispersions of pinostrobin oxime with disodium salt of glycyrrhizated acid and pinostrobin oxime with arabinogalactan is not displayed, which is associated with the intermolecular interaction of the components of the complex, where the molecule of pinostrobin oxime forms a bond with a complexformation agent during mechanochemical treatment. The complex of pinostrobin oxime with magnesium carbonate is not formed, as evidenced by the thermal curve, where the melting of the sample begins at 182 °C, and complete destruction occurs at a temperature of 782 °C, which is similar to the melting peak of the initial pinostrobin oxime. The results of studying intermolecular bonds in complexes of pinostrobin oxime by the method of NMR-relaxation indicate that the times of spin-lattice and spin-spin relaxation are very sensitive to intermolecular interaction and to the diffusion mobility of molecules.

An effective culture system for producing embryos was developed from isolated microspores of sweet pepper (Capsicum annuum L.). The present work aimed to define exogenous arabinogalactan proteins (AGPs) on the embryogenesis of sweet pepper under the growth environments of donor plants. The experiments were performed with the cultivars Arancia, California wonder, Californium, Camelot, Inspiration, Plato, and Taranto under three different growth environments of the donor plants. The impacts of the different numbers of sweet pepper ovaries (0, 5, 10, and 15) were evaluated on microspore embryogenesis of cultivars in a factorial design with five replications. The simultaneous application of 10 ovaries in stress (sucrose starvation; temperature) and induction media resulted in the highest embryogenesis of the seven aforementioned cultivars under field conditions. Also, the impacts of 0, 80, 120, and 200 mg L−1 gum arabic were studied on embryogenesis in stress and induction media. The treatments containing 120 mg L−1 gum arabic showed the highest embryogenesis across all cultivars, except the California Wonder cultivar in the field conditions. Also, the simultaneous impact of the number of ovaries and concentrations of gum arabic on embryogenesis were studied. A combination of ten ovaries and 120 mg L−1 gum arabic generated the highest embryogenesis in the majority of cultivars. The results revealed that ovaries of sweet pepper and gum arabic had a significant impact on the efficiency of microspore embryogenesis in sweet pepper plants under field conditions.

New water-soluble SeS2 containing nanocomposites are obtained via ion-exchange interaction between selenous acid and ammonium sulfide in water using natural arabinogalactan and starch polysaccharides as nanoparticle stabilizers. The transmission electron microscopy, X-ray diffraction analysis, and dynamic light scattering data show that nanocomposites are formed as spherical crystalline SeS2 nanoparticles 5–140 nm in size, dispersed in polysaccharide matrices. The type of stabilization matrix and ratio of reactants have a decisive influence on the nanomorphological properties of the materials obtained.

The aim of this research was to introduce and characterize a novel plant-based polysaccharide. Ornithogalum cuspidatum (OC) was used for mucilage extraction and chemical, physical, thermal and rheological properties of raw extracted mucilage (OMA), purified (OMB) and acid hydrolyzed mucilage (OMC) were compared. The purified mucilage (OMB) had the highest molecular weight (1.7 × 106 kDa). Nuclear magnetic resonance spectroscopy showed that the extracted mucilage is a member of arabinogalactan family. high performance liquid chromatography analysis showed that the mucilage is a hetropolysaccharide composed of galactose, glucose, arabinose and galacturonic acid, that galactose was the main monosaccharide in all samples. The functional groups and morphology of samples were characterized by Fourier transform infrared and Field emission scanning electron microscope analyses, respectively. Zeta potential was negative for three samples indicating the anionic nature of mucilage. The thermal analysis showed that the highest thermal stability was related to sample OMC. Water holding capacity of sample OMB was significantly higher than other two samples (p

Common centaury (Centaurium erythraea Rafn) is a medicinal plant of great importance for both pharmaceutical and food industries. Distribution of arabinogalactan proteins (AGPs) with specific epitopes recognized by seven monoclonal antibodies (mAbs) was investigated during indirect somatic embryogenesis (ISE) and shoot organogenesis (ISO) in centaury leaf culture. Dynamic changes were observed in localization of JIM4, JIM8, JIM13, JIM15, LM2, LM14, and MAC207 epitopes during somatic embryo (SE) and adventitious bud (AB) development. AGPs responded to all tested mAbs and expressed in numerous meristematic centers that were formed on leaf explants. In globular SEs, the distribution pattern of JIM4, JIM13, JIM15, LM2, and MAC207 epitopes was observed, while during the progression of somatic embryo development, the number of detected AGPs decreased. During formation of ABs, the number of detected AGPs also decreased. In fully formed ABs, only JIM4 and MAC207 were detected. The present study suggests JIM13 antibody as a marker for ISE in centaury leaf culture. These results implicated that AGPs were developmentally regulated during centaury ISE and ISO.

Prunus armeniaca gum exudate (PAGE) is obtained from the trunk branches of apricot trees. PAGE is a high‐molecular‐weight polysaccharide with arabinogalactan structure. The physicochemical and rheological characteristics of this gum have been investigated in various researches. PAGE offers a good potential for use as an emulsifying, binding, and stabilizing agent in food and pharmaceutical industries. It also can be used as an organic additive in tissue culture media, synthesizing of metallic nanoparticles, binding potential in tablets, antioxidant agent, and corrosion inhibitor. For desirable emulsifying, stabilizing, shelf life‐enhancing properties, and antioxidant activity of PAGE, it can be used as additive in many foods. We present here a comprehensive review on the existing literatures on characterization of this source of polysaccharide to explore its potential applications in various systems., We present here a comprehensive review on the existing literatures on characterization of this source of polysaccharide to explore its potential applications in various systems.

Studies were conducted on two groups of calves during the growing period from 1 to 6 months in conditions of unfavorable respiratory and gastrointestinal diseases. Calves of the experimental group with a diet were given dihydroquercetin and arabinogalactan at a dose of 1 and 75 mg/ kg of live weight / day, respectively. DHQ and AG, in accordance with their biological properties, provided a high level of antioxidant protection, the formation of microbiocenosis and intestinal immunity, correction and control of mineral homeostasis in the body of calves. As a result, there was a normalization and increase in the intensity of protein, nitrogen, lipid, carbohydrate, energy and mineral metabolism, improved the functional state of the liver and increased pathogenetic resistance, which generally had a positive effect on the formation of productive health, viability and resistance of the body to the action of biotic and abiotic environmental factors, safety and average daily growth of calves.

Recently, research associated with natural anti-oxidants leads to the chemical characterization of many compounds possessing strong anti-oxidant activity. Among these anti-oxidants, naturally occurring carbohydrate polymers containing pectic arabinogalactans esterified with phenolic acids in monomeric and dimeric forms are noteworthy. The presence of highly branched arabinogalactan type II side chains and sugar linked phenolic acid residues have been resolved as important parameters. The anti-oxidant activity of these compounds depend on their ability to convert free radicals into stable by-products and themselves oxidized to more stable and less reactive resonance stabilized radicals. Moreover, these carbohydrate polymers form water soluble stable complexes with protein. Such findings support their applications in a diversity of fields including food industry and pharmacy. This review highlights experimental evidences supporting that the carbohydrate polymers containing phenolic polysaccharides may become promising drug candidate for the prevention of aging and age related diseases.

Ulcerative colitis (UC) is an incurable chronic inflammation of the enteric tract. The aim of this study was to investigate the protective effects of arabinogalactan from Lycium barbarum on DSS-induced chronic colitis. A homogeneous arabinogalactan was isolated and purified from L. barbarum, named LBP-3, which mainly consisted of arabinose and galactose with a molar ratio of 1.00 : 0.82. LBP-3 treatment remarkably alleviated body weight loss, histopathological damage and the overproduction of pro-inflammatory cytokines and enzymes in UC mice. Additionally, the intestinal barrier integrity was partially recovered by the up-regulated expression of MUC2 and tight junction proteins. Moreover, the gut microbiota shift was reversed by LBP-3 administration by enriching potential probiotic bacteria (e.g., Ruminococcaceae) and inhibiting the proliferation of harmful bacteria (e.g., Enterobacteriaceae). Furthermore, SCFAs, as major metabolites of LBP-3 fermentation by gut microbiota, were also promoted so as to maintain relatively favorable intestinal homeostasis. Overall, our findings suggested LBP-3 from L. barbarum could be a potential therapeutic candidate against UC via improving intestinal barrier function and partially restoring gut microbiota and its metabolites.

The arabinogalactan of Corynebacterianeae is a critical heteropolysaccharide that tethers outer membrane mycolic acids to peptidoglycan thus forming the characteristic cell wall core of these prokaryotes. An essential α-(1→5)-arabinosyltransferase, AftA, is responsible for the transfer of the first arabinofuranosyl (Araf) unit of the arabinan domain to the galactan backbone of arabinogalactan, but the number and precise position at which Araf residue(s) is/are added in mycobacteria remain ill-defined. Using membrane preparations from Mycobacterium smegmatis overexpressing aftA, farnesyl-phospho-arabinose as an Araf donor, and a series of synthetic galactan acceptors of various lengths, we here show that a single priming arabinosyl residue substitutes the C-5 position of a precisely positioned internal 6-linked galactofuranosyl residue of the galactan acceptors, irrespective of their length. This unexpected result suggests that, like the structurally related mycobacterial lipoarabinomannans, the arabinogalactan of mycobacteria may in fact harbor a single arabinan chain.

Barks of trees of the genus Handroanthus are known for their antitumor activity, which is attributed to naphthoquinones. Another class of molecules that has shown antitumor activity are the polysaccharides, however those from Handroanthus barks have never been studied. Accordingly, the aim of this study was to extract polysaccharides from H. heptaphyllus and H. albus barks, to characterize them structurally and to evaluate their cytotoxic effects on the human colon and human breast cancer cell lines, Caco-2 and MCF-7, respectively. The polysaccharides were extracted with boiling water and fractionated by freeze-thawing process. The soluble polysaccharide fractions HHBSF and HABSF were characterized by monosaccharide composition, methylation and NMR analyses, and their effects on proliferation of Caco-2 and MCF-7 cells were evaluated using MTT cell viability assay. HHBSF and HABSF were mainly constituted of galactoglucomannan, type II arabinogalactan (AGII) and type I rhamnogalacturonan (RGI), however, only HABSF significantly inhibited the growth of MCF-7 (CC50 = 327 μg/mL) and Caco-2 (CC50 = 2258 μg/mL) cells. Differences in the fine structure and proportion of their polysaccharides, and maybe in the composition of associated phenolic compounds could explain the different effects of HHBSF and HABSF.

A comparison of IR spectra and molecular weight distribution of arabinogalactan sulfates as sodium and ammonium salts obtained using various sulfating reagents was performed. According to the data, sulfated derivatives of arabinogalactan differ from each other in the nature of hydrogen bonds and molecular weight distribution. Using coagulological tests during activation of coagulation of platelet-poor human plasma in vitro, the anticoagulant properties of sulfated arabinogalactan derivatives in various salt forms differing in the preparation method, sulfation degree, and molecular weight were studied. It was found that the sample in the form of the sodium salt of sulfated arabinogalactan (SAG 1) with a sulfur content of 13.2 wt % and a polydispersity degree of 1.52 exhibited twofold greater anticoagulant activity than the sample in the form of the ammonium salt of sulfated arabinogalactan (SAG 2) with a sulfur content of 6.6 wt % and a polydispersity degree of 1.30. The antithrombin (aIIa) activity of the samples obtained by sulfation with a complex of pyridine and sulfuric anhydride (SAG 1) and a complex of sulfamic acid (SAG 2) was 23.42 ± 1.86 and 10.20 ± 1.50 U/mg, respectively; the value of the antifactor Xa activity of SAG 1 and SAG 2 was 2.13 ± 0.42 and 0.37 ± 0.08 U/mg; the aIIa/aXa ratio for SAG 1 and SAG 2 was 11 and 28, respectively. The antifactor Xa (aXa) activity of SAG, which is lower than that of unfractionated heparin (UFH), and a high aIIa/aXa activity ratio may contribute to less provocation of bleeding by SAG samples compared to UFH.

Introduction. Based on arabinogalactan, a complex of hybrid nanobiocomposites has been created, which carry a balanced amount of macro- and microelements necessary for the body. A feature of the action of nanoparticles on the body is their ability to easily penetrate all organs and tissues. The aim of the work is to study the effect of copper arabinogalactan on the content of copper in the main tissues and organs of rats. Material and methods. The content of copper in organs and tissues of rats after a 10-day intragastric administration of a solution of copper arabinogalactan in a dose of 500 μg per kg of weight was studied by the atomic absorption method. Results. A high level of copper (above 2 μg/g) was found in wool, kidneys, liver, and heart. The brain and testes contain from 1 to 2 μg/g of copper. In the tissues of the stomach, small and large intestines, thymus, pancreas, blood, eyes, spleen, lungs, and skeletal muscles - less than 1 μg/g. Conclusion. The study of the distribution of copper in the organs of rats after oral administration of the nanocomposite of copper oxide with arabinogalactan demonstrated the main target organs for the accumulation of the element to be the kidneys, liver, brain, and stomach. The different character of the accumulation of copper in the tissues of the body of the rats received arabinogalactan of copper in the form of a nanocomposite, may indicate the selective ability of tissues and organs to accumulate this element. For further work on the possible use of the drug for medicinal purposes, it is necessary to take into account the peculiarities of biodistribution and bioaccumulation in various organs.

The effect of aqueous extract of pine needles, pine nut shells and arabinogalactan on the metabolism of dairy cows was studied. The objectives of the research were to investigate the elemental composition of aqueous extract of pine needles, pine nut shells and arabinogalactan and to study the effect of cows’ feeding on aqueous extract containing these supplements on the biochemical parameters of blood, physical and biochemical parameters of cows’ urine. The experiment was carried out in theKrasnoyarskTerritoryon black-and-white cows at the age of fi calving with an average body condition and life weight of 580-600 kg. Two groups of cows were formed, 10 animals in each. The duration of the experiment was 100 days. The cows were kept tied, in year-round stalls, milking was carried out automatically into the milk pipe. According to the scheme of the experiment, the control group was fed on the main diet, the experimental group was given aqueous extract (200 ml/head/day) of pine needles (15 g/l), pine nut shells (25 g/l) and arabinogalactan (25 g/l) in addition to the main diet. The test infusion was fed in a mixture with concentrated feed. The feeding ration corresponded to the zootechnical standards. It was found that feeding cows on aqueous extract of the studied forest components did not have a negative eff on the metabolism in the body of the animals: the biochemical parameters of blood and the physicochemical parameters of cows’ urine corresponded to the norm of healthy animals. At the same time, metabolic processes in the blood of the cows in the experimental group were very intensive, mineral and carbohydrate metabolism improved, as evidenced by an increase in glucose content by 16.6%, iron – by 17.8, phosphorus – by 13.0%.

The extract from leaves of Genipa americana L., Rubiaceae, has antichagasic effect. The major components of this extract, arabinogalactan-glycoconjugate fractions (PFI and PFII), have shown similar biological effects of the crude extract, becoming interesting to evaluate the antichagasic effect of PFI and PFII. This work aimed to access the trypanocidal effect of PFI and PFII against the benznidazole-resistant Trypanosoma cruzi Y strain and to investigate the mechanism of action. PFI and PFII were evaluated on epimastigote (24, 48, 72 h), trypomastigote (24 h), and amastigote (24 and 48 h) forms. The cytotoxicity on LLC-MK2 cells was made by MTT assay. Flow cytometry analysis with PE-annexin V (Ax), 7-AAD, and DCFH-DA staining and scanning electron microscopy (SEM) were performed in epimastigote forms for evaluation of the cell death pathway. PFI showed effect against epimastigote forms (EC50/24 h = 580 ± 0.17 μg/ml; EC50/48 h = 530 ± 0.13 μg/ml; EC50/72 h = 500 ± 0.14 μg/ml), while PFII did not show effect on any tested concentrations. In trypomastigotes, the PFI and PFII showed effect with EC50 values of 100 ± 0.09 and 23 ± 0.06 μg/ml respectively. PFI and PFII were also able to decrease amastigotes/100 cells parameter. PFI and PFII were not cytotoxic in LLC-MK2 cells at the highest tested concentration, resulting in selectivity index (SI) higher than 15 for PFI and higher than 65 for PFII. The increase in labeling of 7-AAD and DCFH-DA fluorescence on cytometry flow assays suggested necrosis as the cell death pathway of PFI in epimastigotes of T. cruzi, being confirmed by pores in the membrane observed on SEM. PFI and PFII are partially responsible by the trypanocidal effect of the crude extract of G. americana, with PFI showing the same action mechanism of crude extract and PFII being the most selective and potent fraction, presenting the biotechnological potential for antichagasic natural products.

The growth-stimulating activity of three selenium nanocomposites (NCs) in various matrices based on arabinogalactan (NC Se/AG, 6.4% Se), starch (NC Se/St, 2% Se), and carrageenan (NC Se/Car, 12% Se) with respect to plants of radish, soybean, and potato was investigated. It was shown that the treatment of plant seeds with NCs stimulated root growth during germination. It was found that the studied NCs affected both the level of lipid peroxidation and the activity of the antioxidant enzyme glutathione peroxidase (GPX). The treatment of radish seeds with NCs stimulated root growth during their germination and reduced the content of diene conjugates (DC) in root tissues. It was shown that soaking seeds in NC Se/AG solution increased the GPX activity in the tissues of the radish root by 40%. Stimulation of soybean root growth under the influence of NC Se/Car may also be associated with the activation of GPX. Furthermore, in potato plants, this NC led to the stimulation of germination; however, this was probably due to the activation of other antioxidant enzymes. The results obtained allow us to consider Se NCs as potential plant growth stimulants.

In the manuscript, water-soluble polysaccharides WPNI was extracted from notopterygium incisum roots and separated into two homogeneous fractions WPNI-A-a and WPNI-A-b. WPNI-A-a was an arabinogalactan (AG). WPNI-A-b belonged to HG type pectin. The structure of WPNI-A-b was analyzed by FT-IR, NMR, enzymatic hydrolysis (Endo-PG) and UPLC-FLD-MSn. WPNI-A-b was dominated by HG domain, covalently linked with AG and RG-II domains. Oligogalacturonides produced by Endo-PG from HG domain were non-, mono-, di- or tri-methyl esterified with degree of polymerization (DP) from 1 to 6. The distribution of methyl-ester groups was in a block-wise manner. The interaction of WPNI-A-b and its enzymatic hydrolysis products with galectin-1, galectin-3, galectin-7 and galectin-8 showed that AG domain exhibited stronger binding avidity to galectins than RG-II and HG domain, while oligogalacturonides showed no binding activities to galectins. The results would be useful for the application of the pectin from notopterygium incisum.

The aim of the present study was to unveil the chemopreventive potentials of aqueous Tinospora cordifolia stem extract and its active component viz. Arabinogalactan against Benzo(a)pyrene-induced pulmonary carcinogenesis. Animals were divided into six groups: (I) Control, (II) aqueous Tinospora cordifolia (200 mg/kg b.wt, p.o.), (III) arabinogalactan (7.5 mg/kg b.wt, p.o.), (IV) benzo(a)pyrene (50 mg/kg b.wt, i.p.) at second and fourth week of study, (V) benzo(a)pyrene + aqueous Tinospora cordifolia, and (VI) benzo(a)pyrene + arabinogalactan. The benzo(a)pyrene treatment resulted in severe alterations in the cellular arrangement and morphology of the alveolar tissue in benzo(a)pyrene group. However, benzo(a)pyrene + aqueous Tinospora cordifolia and benzo(a)pyrene + arabinogalactan groups revealed classical features of apoptosis including chromatin condensation and formation of apoptotic bodies. Furthermore, Fourier transform Infrared spectroscopy analysis showed disturbed phospholipid saturation and protein secondary structures in benzo(a)pyrene treated animals. Depletion in relative glycogen and enhancement in total nucleic acid content was observed in benzo(a)pyrene treated animals, and the same was found to be restored upon arabinogalactan and aqueous Tinospora cordifolia supplementation. Benzo(a)pyrene insult also upregulated the phase I carcinogen metabolizing enzymes and differentially modulated the phase II metabolizing enzymes during pulmonary carcinogenesis. Also, depleted (reduced glutathione) and increased lipid peroxidation levels were observed in benzo(a)pyrene treated animals, which was found to be normalized upon aqueous Tinospora cordifolia and arabinogalactan administration. Clastogenic damage inflicted by benzo(a)pyrene was also reversed in benzo(a)pyrene + aqueous Tinospora cordifolia and benzo(a)pyrene + arabinogalactan group. Thus, the present study infers that aqueous Tinospora cordifolia and arabinogalactan showed promising anticancer activity against lung tumorigenesis in terms of ultrastructural, biochemical, and biomolecular aspects.

Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy‐protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy‐protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subsequently coupled to a carrier protein to form a neoglycoconjugate. The allergy‐protective activity of arabinogalactan could be reproduced with the partial structure in subsequent in vivo experiments. This is the first example of a successful simplification of arabinogalactan with a single partial structure while retaining its allergy‐preventive potential., Total synthesis of a pentasaccharide containing l‐arabinose‐ and d‐galactose was accomplished and covalently coupled to a carrier protein to form a neoglycoconjugate that mimics partial structures of allergy‐preventive arabinogalactan. Inhalative treatment of mice with the neoglycoconjugate protects them against allergic inflammation by the induction of immune regulation involving antibodies and interleukin‐10.

Cereus hildmannianus is a cactus exhibiting morphological and physiological adaptation of its cladodes which ensuring growth in climatic and soil conditions unfavourable for many plant species. Currently, limited water resources and increasing demand for renewable energy make cacti a biomass source for the production of biofuels. Somaclones regenerated from callus in vitro can be a source of new raw material in useful plants. The objective of this work was to determine if the regenerated plants showing two different morphologies present polysaccharide composition different from the wild plant. Somaclones aqueous extraction shows the absence of soluble polysaccharides as mucilage. The alkaline extraction of in vivo cultivated plant showed the presence of starch, type I arabinogalactan, and arabinoxylan and the somaclones showed type I arabinogalactan and arabinoxylan in both morphologies. Hemicelluloses found in the somaclones are not different from in vivo cultivated plants, but somaclones not almost biosynthesize mucilage and starch.

Siraitia grosvenori fruits are used as a sweetener and in traditional medicine. Their composition is more frequently studied contrary to flowers or herbal tea made of this plant. Infusions or decoctions of S. grosvenori flowers and herbal tea, commercially available products for daily use, are ingested into our body in terms of herbal medicine with potentially health beneficial impact. Mogrosides are supposed to be responsible for biological activities of S. grosvenori; however, it is well known that polysaccharides can also exhibit interesting biological activities. Composition of purified polysaccharidic complex matrices, isolated from S. grosvenori flowers and herbal tea by infusion and decoction, was the target of our study performed mainly by GC–MS and NMR. Characteristic NMR spectral features allowed an identification of the arabinogalactan type II and acidic biopolymers, homogalacturonan and highly esterified homogalacturonan in infusions of the herbal tea and flower and decoction of flowers. In the decoction sample of herbal tea inulin was found as the dominant polysaccharide. Comparison of compositional and linkage analyses data with those of 2D NMR spectra allowed an identification of fine structural elements of arabinogalactan polymers.

In this study, two pectic polysaccharides from stems of Codonopsis pilosula (CPSP-1) and C. tangshen (CTSP-1) were obtained by ion exchange chromatography and gel filtration. The molecular weight of CPSP-1 and CTSP-1 were 13.1 and 23.0 kDa, respectively. The results of structure elucidation indicated that both CPSP-1 and CTSP-1 are pectic polysaccharides with long homogalacturonan regions (HG) (some of galacturonic acid units were methyl esterified) and rhamnogalacturonan I (RG-I) regions. Side chains for CTSP-1 are both arabinogalactan type I (AG-I) and type II (AG-II), while CPSP-1 only has AG-II. The biological test demonstrated that CPSP-1 and CTSP-1 displayed an antioxidant property through mediating the intestinal cellular antioxidant defense system, which could protect cultured intestinal cells from oxidative stress induced oxidative damages and cell viability suppression. CPSP-1 and CTSP-I showed different bioactivities and mechanisms, which may be due to the difference in their structures.

Transfer cells (TCs) support high nutrient rates into, or at symplasmic discontinuities within, the plant body. Their transport capacity is conferred by an amplified plasma membrane surface area, enriched in nutrient transporters, supported on an intricately invaginated wall labyrinth (WL). Thus, development of the WL is at the heart of TC function. Enquiry has shifted from describing WL architecture and formation to discovering mechanisms regulating WL assembly. Experimental systems used to examine these phenomena are critiqued. Considerable progress has been made in identifying master regulators that commit stem cells to a TC fate (e.g. the maize Myeloblastosis (MYB)-related R1-type transcription factor) and signals that induce differentiated cells to undergo trans-differentiation to a TC phenotype (e.g. sugar, auxin and ethylene). In addition, signals that provide positional information for assembly of the WL include apoplasmic hydrogen peroxide and cytosolic Ca2+ plumes. The former switches on, and specifies the intracellular site for WL construction, while the latter creates subdomains to direct assembly of WL invaginations. Less is known about macromolecule species and their spatial organization essential for WL assembly. Emerging evidence points to a dependency on methyl-esterified homogalacturonan accumulation, unique patterns of cellulose and callose deposition and spatial positioning of arabinogalactan proteins.

Matrix polysaccharides are a diverse group of structurally complex carbohydrates and account for a large portion of the biomass consumed as food or used to produce fuels and materials. Glucuronoxylan and arabinogalactan protein are matrix glycans that have sidechains decorated with 4-O-methyl glucuronosyl residues. Methylation is a key determinant of the physical properties of these wall glycopolymers and consequently affects both their biological function and ability to interact with other wall polymers. Indeed, there is increasing interest in determining the distribution and abundance of methyl-etherified polysaccharides in different plant species, tissues, and developmental stages. There is also a need to understand the mechanisms involved in their biosynthesis. Members of the Domain of Unknown Function (DUF) 579 family have been demonstrated to have a role in the biosynthesis of methyl-etherified glycans. Here we describe methods for the analysis of the 4-O-methyl glucuronic acid moieties that are present in sidechains of arabinogalactan proteins. These methods are then applied toward the analysis of loss-of-function mutants of two DUF579 family members that lack this modification in muro. We also present a procedure to assay DUF579 family members for enzymatic activity in vitro using acceptor oligosaccharides prepared from xylan of loss-of-function mutants. Our approach facilitates the characterization of enzymes that modify glycosyl residues during cell wall synthesis and the structures that they generate.

The effect of the natural saponin glycyrrhizic acid (GA) and polysaccharide arabinogalactan (AG) on the transmembrane potential of rat thymocytes was investigated using the potential-sensitive fluorescent probe 4-(p-dimethylaminostyryl)-1-methylpyridinium (DSM). Incubation of cells with GA in micellar form resulted in a decrease of the amplitude of observed fluorescence kinetics that points out to a decrease of the transmembrane potential. The proposed mechanism is an increase of membrane ion permeability (passive ion transport) of the plasma cell membrane due to GA incorporation. The incorporation of GA molecules into the cell membrane is extremely sensitive to the degree of GA dissociation. The neutral form of glycyrrhizic acid enters the lipid bilayer in contrast to the deprotonated anionic form. The incubation of rat thymocytes with anionic form of GA, namely with its disodium salt, has no effect on the fluorescence kinetics. The possible reasons of this phenomenon are discussed in the light of the nuclear magnetic resonance (NMR) and molecular dynamics (MD) data. The treatment of thymocytes with AG affects only the initial rate of the probe incorporation. The proposed mechanism is that AG covers the surface of the cell membrane and forms a barrier for the probe. Additionally, our experiments demonstrated that both polysaccharide AG and GA in the neutral form (but not Na2GA) effectively capture the cationic probe in an aqueous solution and then deliver it to the cell membrane.