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Buckwheat is introduced into the diet as an alternative crop of renewed interest due to its nutritive and health-promoting value. Experiments with animal models have demonstrated that buckwheat flour may alleviate diabetes, obesity, hypertension, and hypercholesterolemia. A number of nutraceutical compounds exist in buckwheat grains and other tissues. These are a rich source of starch, proteins, antioxidants, and dietary fibre as well as trace elements. The biological value (BV) of buckwheat proteins is comparable to BV of other protein sources. Besides high-quality proteins, buckwheat grains contain some components with prophylactic value: flavonoids, fagopyrins, or thiamin-binding proteins. For the food industry, buckwheat grains are a valuable raw material to be used for the production of functional foods. Buckwheat flour may be a valuable and important ingredient in diets or food products, taking into consideration its nutritive value and potential promotion of human health.

Deproteinization procedure is a fundamental step for analyzing polysaccharide from natural plants. In this study, in the course of refining bioactive polysaccharides from lingzhi (Ganoderma atrum), an effective deproteinization method using lead acetate solution was established by comparing with other available methods. The percentages of deproteinization, polysaccharide loss, and its antioxidant activities loss were used as the index to evaluate and optimize the precipitation experimental conditions. The results showed that the modified method, precipitation with the addition of 0.4–0.52%(w/v) lead acetate, was superior to the others, as evidenced by the highest deproteinization efficiency (88%), as well as the lowest polysaccharide loss (17%). And notably its antioxidant activity also remained good (loss 15%). It provides a simple prefractionation step for the analysis of polysaccharide from natural plants. Polysaccharide isolated by this method is in the native state. Our method may offer a rapid method for removing protein from plant polysaccharides in large scale.

Cereals are generally known to have a positive influence on the general state of the human organism. The attention of the nutritional experts is paid especially to oats and barley. Besides their accessibility, these cereals are interesting due to their relatively high contents of soluble non-starch polysaccharides (fibrous material), out of which beta-glucans have a dominant position from the aspect of health benefit. This paper presents a brief review of the latest knowledge on the positive effects of beta-glucans on the consumer's health. The structure, occurrence, sources, and positive physiological effects of beta-glucans on the cardiovascular system but also their antibacterial, antitumoral, immunomodulant, and radioprotective properties are mentioned. In the paper are given examples of beta-glucans exploitation as functional ingredients in food, cosmetic, and pharmaceutical industries and as food additives on the basis of cereal fibres and cereal beta-glucans.

▪ Abstract  New and exciting developments in boron research in the past few years greatly contributed to better understanding of the role of boron in plants. Purification and identification of the first boron-polyol transport molecules resolved much of the controversy about boron phloem mobility. Isolation and characterization of the boron-polysaccharide complex from cell walls provided the first direct evidence for boron crosslinking of pectin polymers. Inhibition and recovery of proton release upon boron withdrawal and restitution in plant culture medium demonstrated boron involvement in membrane processes. Rapid boron-induced changes in membrane function could be attributed to boron-complexing membrane constituents. Boron may affect metabolic pathways by binding apoplastic proteins to cis-hydroxyl groups of cell walls and membranes, and by interfering with manganese-dependent enzymatic reactions. In addition, boron has been implicated in counteracting toxic effects of aluminum on root growth of dicotyledonous plants. Molecular investigations of boron nutrition have been initiated by the discovery of a novel mutant of Arabidopsis thaliana with an altered requirement for boron.

A water-soluble polysaccharide was isolated and purified from the culture filtrate of the photosynthetic green microalgae Haematococcus lacustris by 75% ethanol precipitation and Sepharose CL-6B column chromatography. The molecular mass of the purified polysaccharide (named HCP) was estimated to be approximately 135 kDa by size-exclusion HPLC and its monosaccharide composition was galactose, glucose and mannose at a relative molar ratio of 2.0, 1.0, and 4.1, respectively, suggesting that HCP is a galactomannan. Fourier-transform infrared and elemental analysis revealed that the purified HCP contains sulfate esters by 1.08% (in mass) and no detectable level of protein. The HCP significantly stimulated murine macrophage RAW264.7 cells to secrete the pro-inflammatory cytokine, TNF-α, in a dose-dependent manner and also enhanced the expression of COX-2 and iNOS genes at a concentration of lower than 10 ㎍/mL HCP. These results indicated that the sulfated HCP of H. lacustris has potent early innate immune stimulating activities.

Innate nonself recognition must rely on common structures of invading microbes. In a differential display screen for up-regulated immune genes in the moth Trichoplusia ni we have found mechanisms for recognition of bacterial cell wall fragments. One bacteria-induced gene encodes a protein that, after expression in the baculovirus system, was shown to be a peptidoglycan recognition protein (PGRP). It binds strongly to Gram-positive bacteria. We have also cloned the corresponding cDNA from mouse and human and shown this gene to be expressed in a variety of organs, notably organs of the immune system-i.e., bone marrow and spleen. In addition, purified recombinant murine PGRP was shown to possess peptidoglycan affinity. From our results and the sequence homology, we conclude that PGRP is a ubiquitous protein involved in innate immunity, conserved from insects to humans

Two polysaccharides (WEA and WEB) were isolated from Enteromorpha intestinalis by hot water extraction, anion-exchange, and gel-permeation chromatography. The average molecular weights (Mw) of the two fractions were 72.03 kDa (WEA) and 60.12 kDa (WEB). WEA was composed of Rha, Xyl, Man, and Glc in a molar ratio of 1.39:1.00:0.13:3.23. WEB consisted of Rha, Xyl, Gal, and GlcA (glucuronic acid) in a molar ratio of 7.32:1.00:0.51:1.28. Both polysaccharides could inhibit tumor growth in S180 tumor-bearing mice, and increased the relative spleen and thymus weight. They also increased the expression of tumor necrosis factor-alpha (TNF-α) in serum. WEA and WEB induced lymphocyte proliferation, increased the production of TNF-α in macrophages, and stimulated macrophages to produce nitric oxide dose-dependently through the up-regulation of inducible NO synthase activity. However, no direct cytotoxicity against Sarcoma 180 was investigated in vitro. These results indicate that the antitumor effects of these polysaccharides are associated with immunostimulation.

Protein-polysaccharide conjugates were generally prepared by dry-heating. However, it was time-consuming and the sample gained was inhomogeneous. A faster way of preparing protein-polysaccharide conjugates is needed. Accordingly, soy protein isolates (SPI)-acacia gum (GA) conjugates prepared by the wet-heating method were studied in the present work. Physicochemical properties of SPI-GA conjugates were also determined. The results showed that the wet-heating method could improve the rate of the graft reaction of protein and polysaccharide. The solubility of SPI-GA conjugates was significantly higher than that of unreacted SPI-GA mixtures and SPI at the same pH values. The emulsion activity index of the grafted SPI increased remarkably. Moreover, a significant improvement of the emulsifying stability index was observed and emulsions with a smaller droplet size were obtained. No visible flocculation during extended storage (30 days) was observed. The time course of the development of the graft reaction of SPI with GA was also shown by SDS-PAGE.

For a better understanding of Al inhibition of root elongation, knowledge of the morphological and functional organization of the root apex is a prerequisite. We developed a polyvinyl chloride-block technique to supply Al (90 micromolar monomeric Al) in a medium containing agarose to individual 1-mm root zones of intact seedlings of maize (Zea mays L. cv Lixis). Root elongation was measured during a period of 5 h. After Al treatment, callose (5 h) and Al (1 h) contents of individual 1-mm apical root segments were determined. For comparison, callose and Al levels were also measured in root segments after uniform Al supply in agarose blocks to the 10-mm root apex. Only applying Al to the three apical 1-mm root zones inhibited root elongation after 1 h. The order of sensitivity was 1 to 2 0 to 1 2 to 3 mm. In the 1- to 2-mm root zone high levels of Al-induced callose formation and accumulation of Al was found, independently of whether Al was applied to individual apical root zones or uniformly to the whole-root apex. We conclude from these results that the distal part of the transition zone of the root apex, where the cells are undergoing a preparatory phase for rapid elongation (F. Baluska, D. Volkmann, P.W. Barlow [1996] Plant Physiol 112: 3-4), is the primary target of Al in this Al-sensitive maize cultivar

Sucrose synthase (SuSy; EC 2.4.1.13; sucrose + UDP reversibly UDPglucose + fructose) has always been studied as a cytoplasmic enzyme in plant cells where it serves to degrade sucrose and provide carbon for respiration and synthesis of cell wall polysaccharides and starch. We report here that at least half of the total SuSy of developing cotton fibers (Gossypium hirsutum) is tightly associated with the plasma membrane. Therefore, this form of SuSy might serve to channel carbon directly from sucrose to cellulose and/or callose synthases in the plasma membrane. By using detached and permeabilized cotton fibers, we show that carbon from sucrose can be converted at high rates to both cellulose and callose. Synthesis of cellulose or callose is favored by addition of EGTA or calcium and cellobiose, respectively. These findings contrast with the traditional observation that when UDPglucose is used as substrate in vitro, callose is the major product synthesized. Immunolocalization studies show that SuSy can be localized at the fiber surface in patterns consistent with the deposition of cellulose or callose. Thus, these results support a model in which SuSy exists in a complex with the beta-glucan synthases and serves to channel carbon from sucrose to glucan.