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We designed stable and highly reproducible hydrogels by external unidirectional diffusion of Fe 2+ ions into aqueous solutions of polygalacturonate (polyGal) chains. The Fe 2+ ions act as cross-linkers between the Gal units in such a way that both the molar ratio R ([Fe 2+ ]/[Gal units] = 0.25) and the mesh size of the polyGal network at the local scale (ξ = 75 ± 5 Å) have constant values within the whole gel, as respectively determined by titration and Small Angle Neutron Scattering. From macroscopic point of view, there is a progressive decrease of polyGal concentration from the part of the gel formed in the early stages of the gelation process, which is homogeneous, transparent and whose Young modulus has a high value of ∼10 5  Pa, up to the part of the gel formed in the late stages, which is heterogeneous, highly turbid and has a much lower Young modulus of ∼10 3  Pa. Since the local organization of the polyGal chains remains identical all along the hydrogels, this macroscopic concentration gradient originates from the formation of heterogeneities at a mesoscopic length scale during the gelation process. In addition, X-ray Absorption Spectroscopy measurements remarkably reveal that Fe 2+ ions keep their +II oxidation state in the whole gels once they have cross-linked the Gal units. These polyGal hydrogels thus protect iron against oxidation and could be used for iron fortification., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The present study is focused on the development of a composition based on three pectin metal complexes (NaMg‐PG, NaZn‐PG and NaCr‐PG) at a mass ratio 7:0.3:0.001. It was evaluated by the methods of infrared spectroscopy (IR spectroscopy), atomic force microscopy (AFM), dynamic light scattering (DLS) and TEM‐EDS. The data, obtained by simultaneous thermal analysis and Fourier transform IR spectroscopy, showed that water was the main component of the gas phase at the first stage of mass loss of the specified compounds, whereas further heating led to decarboxylation and degradation. The results of Forced Swim Test (FST) showed that the specified composition at the dose of 50–100 mg/kg contributed to the stimulation of an organism's adaptive capacity under intensive physical loads and could be considered as a potential adaptogen and stimulator of erythropoiesis that could normalize metabolism. [ABSTRACT FROM AUTHOR]

Esterified acid soluble pectins from flax (Linun usitatissimumL.) were degraded either with HCl or pectin lyase. Centrifugation and 2-propanol precipitation led to the isolation of two low molecular weight polygalacturonates after acid hydrolysis of pectins. However, after pectin lyase digestion and purification by size-exclusion HPLC,1H NMR analyses indicated that acetylated hairy regions, large methylated and acetylated oligogalacturonides together with small unsubstituted oligogalacturonides were produced. Thus, in a few steps, a panel of substituted neutral and acidic oligosaccharides was produced from a raw plant material. Such oligosaccharides could be useful for further fractionations such as chemical saponification and enzymatic removal of neutral sugar chains from the hairy regions. The procedures used for pectin extraction, for degradation, and for the purification of fragments seem appropriate for large-scale production of biologically active oligosaccharides from flax. [ABSTRACT FROM AUTHOR]

Cell walls isolated from dicotyledon tissues compete with natural plant host sites for Agrobacterium tumefaciens (strain B6) when co-inoculated with infectious bacteria, thereby reducing tumor initiation. Removal of the pectic fraction from the cell walls results in loss of inhibition and the soluble pectic fraction is inhibitory. On treatment with pectin methyl transferase plus S-adenosyl-L-methionine these cell walls become less inhibitory and this change is reversible by pectinesterase. Cell walls isolated from monocotyledons, crown gall tumors or embryonic dicotyledons do not compete for Agrobacterium in the infection assay. These cell walls, become inhibitory on treatment with pectinesterase and this is partially reversed by pectin methyl transferase. These data indicate that the pectic portion of the host cell wall is involved in the Agrobacterium-host adherence which is essential for tumor initiation and that the degree of methylation of polygalacturonic acid is critical to this adherence. [ABSTRACT FROM AUTHOR]