The clay-polysaccharide interaction is of practical importance in the formation and stabilization of soil aggregates. This study examined the adsorption of three synthetic polysaccharides (PSS) and one soil PSS on Silver Hill illite. The adsorption of PSS was influenced by both the adsorbed cations on the adsorbents and the charge characteristics of the polymers. The adsorbed cations formed different surface complexes with the clay surfaces, with varying ability to screen the surface negative charge and thereby influenced the adsorption of charged polymers. Na-illite adsorbed substantially higher amounts of the cationic PSS, but lower amounts of the anionic PSS, than hydroxy-Al illite. The adsorption of the nonionic PSS was, however, little influenced by those adsorbed cations. The adsorption of the soil PSS resembled that of anionic PSS. However, it yielded linear adsorption isotherms due to the heterogeneous nature of the soil PSS. The adsorption of the three synthetic PSS on Na-illite was in the general order: cationic > nonionic > anionic, confirming that electrostatic forces played a role in the adsorption of charged polymers. pH and ionic strength influenced the adsorption of the charged PSS, because of their influences on the charge characteristics of both the polymer and the clay, and on polymer conformation. This study indicates that surface charge properties of both clays and organic polymers and the presence of polyvalent cations in the system are important factors influencing the complexation between soil clays and organic constituents.

Bacteria play an important role in determining the properties and behavior of clay minerals in natural environments and such interactions have great potential for creating stable biofilms and carbon storage sites in soils, but our knowledge of these interactions are far from complete. The purpose of this study was to understand better the effects of bacteria-generated biofilms on clay interlayer expansion. Mixtures of a colloidal, 2-water hectorite clay and Pseudomonas syringae in a minimal media suspension evolve into a polysaccharide-rich biofilm aggregate in time-series experiments lasting up to 1 week. X-ray diffraction analysis reveals that upon aggregation, the clay undergoes an initial interlayer contraction. Short-duration experiments, up to 72 h, result in a decrease in the d001 value from 1.50 to 1.26 nm. The initial interlayer contraction is followed in long-duration (up to 1 week) experiments by an expansion of the d001 value of 1.84 nm. The expansion is probably a result of large, biofilm-produced, polymeric molecules being emplaced in the interlayer site. The resultant organo-clay could provide a possible storage medium for carbon in a microbial colony setting.

Apart from its role as a digestive and absorptive organ, the gastrointestinal (GI) tract is a vital immune organ that encompasses roughly 70 % of the total immune cells of the body. As such, the physical, chemical and nutrient composition of the diet influences overall GI function, effectively as an immune organ. With the improvement in feed technology, agro-industrial co-products that are high in fibre have been widely used as a feed ingredient in the diets of pigs and poultry. Arabinoxylan (AX) and mannan are the most abundant hemicellulosic polysaccharides present in cereal grain and co-product ingredients used in the livestock industry. When monogastric animals consume diets containing high amounts of AX and mannans, stimulation of GI immune cells may occur. This involves the activation of several cellular and molecular pathways of the immune system and requires a considerable amount of energy and nutrients to be expended by the animal, which may ultimately influence overall health and growth performance of animals. Therefore, a better understanding of the role of AX and mannan in immune modulation will be helpful in modulating untoward GI immune responses, thereby minimising nutrient and energy expenditure toward this effort. This review will summarise pertinent research on the role of oligosaccharides and polysaccharides containing AX and mannans in immune modulation in order to preserve gut integrity.

Astragalus membranaceus (AM) is a member of the family Leguminosae which has been widely used as immunomodulatory agent. Astragalus polysaccharides (APS) possess promising biological activities like immune enhancing, anti-oxidant, anti-viral, anti-microbial and anti-parasitic activities. Researchers have studied the immune enhancing activities of AM in birds and reported that APS and sulphated APS (4 or 8 mg/kg of body weight) showed immunomodulatory effects broiler chicks infected with lipopolysaccharide and modulated the resulting negative effects. AM powder supplementation in broiler feed at levels of 0, 100, 200 and 300 mg /kg diet increased the immune organs weight and IgG level and improved the liver and kidney functions and antioxidant status. Dietary APS (10 g/kg) promoted the growth rate and the histology of jejunum of offspring chickens. The addition of crude AM at 0.5% in laying hen feed for 21 days was able to improve the composition of faecal microorganisms. The following review describes the structure and chemical composition of AM and its immunomodulatory role in improving the health status of poultry and its mechanisms of action.

During diabetes, structural and functional changes in the alimentary tract are known to take place resulting in an increased absorption of intestinal glucose and alterations in the activities of brush-border disaccharidases. To elucidate the effect of administrating polysaccharide from Gynura divaricata (PGD) on disaccharidase activities, the specific activities of intestinal disaccharidases, namely sucrase, maltase and lactase, were measured in streptozotocin-induced diabetic rats. Normal control and diabetic rats were treated by oral administration with PGD. Specific activities of intestinal disaccharidases were increased significantly during diabetes, and amelioration of the activities of sucrase and maltase during diabetes was clearly visible by the treatment with PGD. However, the increased activity of lactase during diabetes mellitus was remarkably alleviated by the administration of PGD only in the duodenum. Meanwhile, oral sucrose tolerance tests demonstrated that PGD alleviated the hyperglycaemia during diabetes mellitus, resulting from the amelioration in the activities of intestinal disaccharidases. The present investigation suggests that PGD exerted an anti-diabetic effect partly via inhibiting the increased intestinal disaccharidase activities of diabetic rats. This beneficial influence of administration of PGD on intestinal disaccharidases clearly indicates their helpful role in the management of diabetes.

Introduction. Mature green vanilla pods accumulate 4-O-(3-methoxy-benzaldehyde)-β-D-glucoside (glucovanillin), which, upon hydrolysis by an endogenous β-glucosidase, liberates vanillin, the major aroma component of vanilla. Sites of storage of glucovanillin in the pod have been controversially reported for decades; we aim, using precise and widely accepted technical terminology, to clarify this controversy by providing an anatomical, histochemical and biochemical evidence-based picture of glucovanillin accumulation sites. The pod also synthesizes an oleoresin and a mucilage of unknown constitutions; we report here their localization and structures. Materials and methods. The pod anatomy was examined by light and epifluorescence microscopy. A protocol was established allowing fine hand-dissection of diverse anatomical parts of the pod (mesocarp, placentae, trichomes, intralocular interstitial cell-free region and seeds). Glucovanillin and γ-pyranones were extracted and analyzed by HPLC, while the structures of the mucilaginous polysaccharides were determined after permethylation. Results and discussion. Glucovanillin is essentially stored in the placentae (92%) and marginally in trichomes (7%); traces were measured in the mesocarp and intralocular interstitial cell-free medium. Trichomes store massive amounts of a fluorescing oleoresin (44%) rich in alkenylmethyldihydro-γ-pyranones and synthesize a mucilage made of a glucomannan and a pectic polysaccharide carrying monomeric arabinose and galactose side-chains. Conclusion. To date, the physiological roles of glucovanillin, long-chain pyranones, and mucilage remain unknown.

At its most fundamental, cancer is a genetic disease resulting from inherited or acquired mutations in tumour suppressor genes and proto-oncogenes. Environmental factors, including ingested food components, interact with genetic inheritance to determine individual cancer risk. There is growing evidence that the immune system exerts selective pressure during neoplastic development. Tumour cells that evade this immunosurveillance because they are non-antigenic or because they defend themselves successfully against immune attack have a survival advantage. Effective chemopreventative agents will include dietary components that enhance the immune system’s ability to identify transformed cells and to target them for apoptosis.

Si-Jun-Zi decoction (SJZD), a traditional Chinese herbal prescription, has been used clinically for treating patients with disorders of the digestive system. Previous studies indicated that the polysaccharides of SJZD (SJZPS) are the active components contributing towards its pharmacological effects in improving gastrointestinal function and immunity. However, the protective and restitutive effects on intestinal epithelial cells remain unknown. In the present study, SJZPS were first extracted and chemically characterized. Then their stimulatory and restitutive effects on intestinal epithelial cells (IEC-6 cells) were elicited by different in vitro models including migration of wounded IEC-6 cells and cell proliferation. Results indicated that SJZPS not only protects the cells against the harmful impairment of indomethacin but also enhances re-epithelialization of a wounded monolayer at an optimal dose of 100 μg/ml at 24 h incubation. To elucidate the modulatory effect of SJZPS on wounded IEC-6 cells at the molecular level, an oligonucleotide microarray was employed to study differential gene expression of SJZPS-treated IEC-6 cells and the candidate genes were validated by RT-PCR. There was increased expression of genes coding for ion channels and transporters, which are critical to cell migration and restoration of wounded intestinal cells, suggesting a possible mechanism for re-epithelialization. In conclusion, our data show for the first time that SJZPS can enhance intestinal restitution and protect against indomethacin-induced damage of intestinal epithelial cells. These findings provide new insight into the mechanism of action of a traditional Chinese herbal prescription, SJZD, in intestinal wound restitution.

Chinese natural medicinal products as feed supplements have been used as growth and health promoters in farm animals in China for centuries. A current estimation of the number of Chinese natural medicines ranges between 6,000 and 8,000, of which less than 5% has immuno-active properties. Most of these medicinal products originate from plants. Polysaccharides are considered to be the most important components, which may act as immune enhancers or immuno-modulators. The relationship between polysaccharide structure and bio-activity is, however, not well understood. In this review, immune activities of the polysaccharides from two mushrooms, Lentinus edodes and Tremella fuciformis, and a herb, Astragalus membranaceus radix, are reported, based on studies in chickens, mice, rats and humans. It can be concluded from these studies that polysaccharides derived from these products can play important roles in: (1) stimulating the growth of immune organs such as spleen, thymus and bursa; (2) increasing the number and activities of many interdependent cell types such as T, B lymphocytes, macrophages, natural killer (NK) cells and lymphokine-activated killer (LAK) cells; (3) enhancing T-cell mediated immune response, such as an increased rate of T-lymphocyte transformation and proliferation; (4) enhancing humoral immune response, such as spleen and serum antibody production, the number of haemolytic plague forming cells (PFC) and haemolysin production and (5) inducing secretion and production of cytokines and complements of T-cells and NK cells.

Today's poultry producers are confronted by numerous prophylactic techniques to prevent diseases. The immuno-active polysaccharides from mushrooms and herbs might be good candidates as health promoting feed additives in poultry diets. Further studies are needed to investigate the effects of such bioactive components to improve productive performance in chicken and to elucidate the possible modes of action related to the gut ecosystem and the immune response.

Polysaccharides from thalli of Lasallia pustulata were extracted and characterized. The major fractions were characterized as pustulan, a β-glucan-chitin complex and a β-(1→3)-glucan. Other polysaccharides, which are minor components (less than 5%) solubilized with water from the alkali extracts of thalli, were shown to be galactomannans with a backbone of α-(l→6)- mannose partially substituted at positions 2 by galactofuranose and/or mannopyranose side chains of variable length. The relationship between these polysaccharides and those obtained by the same method from free-living fungi is discussed. The proportion or composition of the different polysaccharides studied was not affected by seasonal environmental conditions over a 2-year period.

The present work was undertaken to study the gastrointestinal effects of wheat and oat dietary fibre (DF) using 40–50 kg pigs cannulated in the terminal ileum. The variables studied were: chemical characteristics of the DF, ileal and faecal digestibility of nutrients and bulking properties of polysaccharides and other major constituents. The wheat products studied included refined wheat flour and wheat fractions rich in the following botanical components: aleurone, pericarp/testa and bran. The oat products used were rolled oats and oat bran. The products varied considerably in DF content (g/kg dry matter) and composition; non-starch polysaccharides (NSP) and Klason lignin content ranged from 34 and 1 g/kg respectively in wheat flour, to 465 and 92 g/kg in pericarp/testa. The main NSPs in the wheat were arabinoxylans (AX) (64–69%) and cellulose (15–31%) and in oats mixed linked β(1 → 3; 1 → 4)-D-glucans (β-glucans; 46–63%) and AX (28–32%). The lowest content of soluble NSP was found in the lignified wheat fractions (bran and pericarp/testa) and the highest in oat bran. Eight diets were produced using the wheat and oat products and studied in two series of experiments using wheat flour as the DF-depleted control. The diets in Expt 1 were based on wheat flour and three iso-DF enriched diets prepared by adding DF from the fractions rich in wheat aleurone, pericarp/testa or bran. In Expt 2, oat bran was added to wheat flour to achieve the same DF intake level as in Expt 1. This series also included diets based on rolled oats and rolled oats plus oat bran. Starch was almost completely digested in the small intestine (0.97–1.00). However, there was a tendency to a slightly lower digestibility of oat starch compared with wheat starch. The recovery of wheat NSP in ileal digesta was 82–104 % compared with 64–66% for oats. The low recovery of NSP in oat diets was primarily due to the low recovery of β-glucans (25–36%). In the large intestine NSP and starch residues were extensively degraded. For the DF-depleted control diets or diets based on oats, 8–17% NSP survived breakdown while in the diets enriched with aleurone, pericarp/testa or bran fractions, NSP recovery was 33, 50 and 38 % respectively. Fermentative breakdown of carbohydrates in the large intestine was estimated to contribute between 10 and 24 % of the energy for maintenance. Energy derived from the inflow of organic acids from the ileum contributed an additional 1–4% of maintenance energy. In wheat endosperm, AX were broken down to a greater extent than cellulose, while the breakdown of AX in pericarp/testa was similar to that of cellulose. This difference in NSP breakdown can be explained by structural differences in the two types of cell walls. The breakdown of oat AX was lower than that of wheat flour. Wheat DF increased faecal bulk primarily by virtue of its physical presence and its water-holding capacity, while the oat DF stimulated faecal output through an increase in microbial biomass (Bach Knudsen et al. 1991). The result was a higher excretion of protein and fat. The higher fat excretion with the oat diets was probably due to a higher bile acid excretion caused by the more extensive fermentation of carbohydrates and the lower lumen pH.