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Increased production of valuable secondary products in plants by leaf applied radiation-processed polysaccharides.
Ahmad, B, Khan, MMA, Jahan, A, Shabbir, A, Jaleel, H
International journal of biological macromolecules. 2020;:286-294
Abstract
Oligosaccharides derived through irradiation of polysaccharides act as efficient plant elicitors and stimulate responses associated with primary as well as secondary metabolic pathways in plants. Reduced molecular weight together with the structural rearrangement, induce plant growth promotion activity in the polysaccharides after irradiation. In addition to the increased activities of different enzymes involved in photosynthesis and nutrient assimilation, various secondary metabolism enzymes are up-regulated by the leaf-applied oligomers. Oligosaccharide-induced elicitation of different signal transduction cascades leads to the increased biosynthesis of valuable secondary metabolism products in plants. The present review presents a comprehensive approach regarding the irradiation-induced structural changes and molecular weight reduction in polysaccharides and their role in increasing the production of economically valuable secondary products in various medicinally important plants. This review also encompasses the role of oligosaccharides in regulation of plant growth and enzyme activities as well as the signal transduction mechanism involved in the elicitation of secondary metabolites.
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Oxidoreductases in Glycoprotein Glycosylation, Folding, and ERAD.
Patel, C, Saad, H, Shenkman, M, Lederkremer, GZ
Cells. 2020;(9)
Abstract
N-linked glycosylation and sugar chain processing, as well as disulfide bond formation, are among the most common post-translational protein modifications taking place in the endoplasmic reticulum (ER). They are essential modifications that are required for membrane and secretory proteins to achieve their correct folding and native structure. Several oxidoreductases responsible for disulfide bond formation, isomerization, and reduction have been shown to form stable, functional complexes with enzymes and chaperones that are involved in the initial addition of an N-glycan and in folding and quality control of the glycoproteins. Some of these oxidoreductases are selenoproteins. Recent studies also implicate glycan machinery-oxidoreductase complexes in the recognition and processing of misfolded glycoproteins and their reduction and targeting to ER-associated degradation. This review focuses on the intriguing cooperation between the glycoprotein-specific cell machineries and ER oxidoreductases, and highlights open questions regarding the functions of many members of this large family.
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3D biofilms: in search of the polysaccharides holding together lichen symbioses.
Spribille, T, Tagirdzhanova, G, Goyette, S, Tuovinen, V, Case, R, Zandberg, WF
FEMS microbiology letters. 2020;(5)
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Abstract
Stable, long-term interactions between fungi and algae or cyanobacteria, collectively known as lichens, have repeatedly evolved complex architectures with little resemblance to their component parts. Lacking any central scaffold, the shapes they assume are casts of secreted polymers that cement cells into place, determine the angle of phototropic exposure and regulate water relations. A growing body of evidence suggests that many lichen extracellular polymer matrices harbor unicellular, non-photosynthesizing organisms (UNPOs) not traditionally recognized as lichen symbionts. Understanding organismal input and uptake in this layer is key to interpreting the role UNPOs play in lichen biology. Here, we review both polysaccharide composition determined from whole, pulverized lichens and UNPOs reported from lichens to date. Most reported polysaccharides are thought to be structural cell wall components. The composition of the extracellular matrix is not definitively known. Several lines of evidence suggest some acidic polysaccharides have evaded detection in routine analysis of neutral sugars and may be involved in the extracellular matrix. UNPOs reported from lichens include diverse bacteria and yeasts for which secreted polysaccharides play important biological roles. We conclude by proposing testable hypotheses on the role that symbiont give-and-take in this layer could play in determining or modifying lichen symbiotic outcomes.
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Polysaccharide nanoparticles for oral controlled drug delivery: the role of drug-polymer and interpolymer interactions.
Bianchera, A, Bettini, R
Expert opinion on drug delivery. 2020;(10):1345-1359
Abstract
Introduction: The oral route still represents the most popular way of administering drugs; nowadays oral administration faces new challenges, in particular with regards to the delivery of APIs that are poorly absorbed and sensitive to degradation such as macromolecules and biotechnological drugs. Nanoparticles are promising tools for the efficient delivery of these drugs to the gastrointestinal tract. Areas covered:Approaches and techniques for the formulation of drugs, with particular focus on the preparation of polysaccharide nanoparticles obtained by non-covalent interactions. Expert opinion:Polysaccharide-based nanoparticulate systems offer the opportunity to address some of the issues posed by biotechnological drugs, as well as by small molecules, with problems of stability/intestinal absorption, by exploiting the capability of the polymer to establish non-covalent bonds with functional groups in the chemical structure of the API. This area of research will continue to grow, provided that these drug delivery technologies will efficaciously be translated into systems that can be manufactured on a large scale under GMP conditions. Industrial scale-up represents the biggest obstacle to overcome in view of the transformation of very promising results obtained on lab scale into medicinal products. To do that, an effort toward the simplification of the process and technologies is necessary.
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Dietary fiber polysaccharides of amaranth, buckwheat and quinoa grains: A review of chemical structure, biological functions and food uses.
Zhu, F
Carbohydrate polymers. 2020;:116819
Abstract
Seeds of amaranth (Amaranthus spp.), buckwheat (Fagopyrum esculentum and F. tataricum) and quinoa (Chenopodium quinoa) become popular foods due to their attractive health effects. Cell wall polysaccharides are the major components of dietary fiber and significantly contribute to diverse health effects of the grains. This review summarizes chemical and physical structure, biological functions and food uses of the cell wall polysaccharides and fractions as fiber components from the 3 pseudocereals. The properties and uses of the polysaccharides and fractions are compared with those of fiber polysaccharides from common sources such as fruits and vegetables. Overall, the fiber polysaccharide composition of the pseudocereals is more similar to that of fruits and vegetables than to that of cereals. The fiber polysaccharides showed a range of biological functions such as antioxidation, anticancer and immunomodulation. The fiber polysaccharides of amaranth, buckwheat and quinoa have potential to be used in formulations of functional foods.
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Research progress on the biological activities of selenium polysaccharides.
Zhou, N, Long, H, Wang, C, Yu, L, Zhao, M, Liu, X
Food & function. 2020;(6):4834-4852
Abstract
Selenium polysaccharides are a new type of functional polysaccharide that combines inorganic selenium with polysaccharides to form an organic selenium product. Selenium polysaccharides are obtained using three different methods, have no toxicity or side effects, and are easily absorbed and utilized by the body. A number of studies have demonstrated that selenium polysaccharides possess better antioxidant, antitumour, immune regulation, hypoglycaemic, and heavy metal removal activities than that of either polysaccharides or inorganic selenium. Selenium polysaccharides have gradually become a research topic of interest for the development of functional foods and pharmaceutical products. However, further studies are required to investigate the structures and mechanisms of selenium polysaccharides. At present, reviews that focus on the bioactivities of selenium polysaccharides are lacking. The aim of this study was to summarize the selenium polysaccharide bioactivity reports from the past decades, describe the mechanisms and shortcomings of these studies, and evaluate the need for further development.
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Intestinal epithelial glycosylation in homeostasis and gut microbiota interactions in IBD.
Kudelka, MR, Stowell, SR, Cummings, RD, Neish, AS
Nature reviews. Gastroenterology & hepatology. 2020;(10):597-617
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Abstract
Inflammatory bowel disease (IBD) affects 6.8 million people globally. A variety of factors have been implicated in IBD pathogenesis, including host genetics, immune dysregulation and gut microbiota alterations. Emerging evidence implicates intestinal epithelial glycosylation as an underappreciated process that interfaces with these three factors. IBD is associated with increased expression of truncated O-glycans as well as altered expression of terminal glycan structures. IBD genes, glycosyltransferase mislocalization, altered glycosyltransferase and glycosidase expression and dysbiosis drive changes in the glycome. These glycan changes disrupt the mucus layer, glycan-lectin interactions, host-microorganism interactions and mucosal immunity, and ultimately contribute to IBD pathogenesis. Epithelial glycans are especially critical in regulating the gut microbiota through providing bacterial ligands and nutrients and ultimately determining the spatial organization of the gut microbiota. In this Review, we discuss the regulation of intestinal epithelial glycosylation, altered epithelial glycosylation in IBD and mechanisms for how these alterations contribute to disease pathobiology. We hope that this Review provides a foundation for future studies on IBD glycosylation and the emergence of glycan-inspired therapies for IBD.
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Interactions between cell wall polysaccharides and polyphenols: Effect of molecular internal structure.
Liu, X, Le Bourvellec, C, Renard, CMGC
Comprehensive reviews in food science and food safety. 2020;(6):3574-3617
Abstract
Cell wall polysaccharides (CPSs) and polyphenols are major constituents of the dietary fiber complex in plant-based foods. Their digestion (by gut microbiota) and bioefficacy depend not only on their structure and quantity, but also on their intermolecular interactions. The composition and structure of these compounds vary with their dietary source (i.e., fruit or vegetable of origin) and can be further modified by food processing. Various components and structures of CPSs and polyphenols have been observed to demonstrate common and characteristic behaviors during interactions. However, at a fundamental level, the mechanisms that ultimately drive these interactions are still not fully understood. This review summarizes the current state of knowledge on the internal factors that influence CPS-polyphenol interactions, describes the different ways in which these interactions can be mediated by molecular composition or structure, and introduces the main methods for the analysis of these interactions, as well as the mechanisms involved. Furthermore, a comprehensive overview is provided of recent key findings in the area of CPS-polyphenol interactions. It is becoming clear that these interactions are shaped by a multitude of factors, the most important of which are the physicochemical properties of the partners: their morphology (surface area and porosity/pore shape), chemical composition (sugar ratio, solubility, and non-sugar components), and molecular architecture (molecular weight, degree of esterification, functional groups, and conformation). An improved understanding of the molecular mechanisms that drive interactions between CPSs and polyphenols may allow us to better establish a bridge between food processing and the bioavailability of colonic fermentation products from CPSs and antioxidant polyphenols, which could ultimately lead to the development of new guidelines for the design of healthier and more nutritious foods.
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Polysaccharides at fluid interfaces of food systems.
Kontogiorgos, V
Advances in colloid and interface science. 2019;:28-37
Abstract
Fabrication of next generation polysaccharides with interfacial properties is driven by the need to create high performance surfactants that operate at extreme environments, as for example in complex food formulations or in the gastrointestinal tract. The present review examines the behaviour of polysaccharides at fluid food interfaces focusing on their performance in the absence of any other intentionally added interfacially active components. Relevant theoretical principles of colloidal stabilisation using concepts that have been developed for synthetic polymers at interfaces are firstly introduced. The role of protein that in most cases is present in polysaccharide preparations either as contaminant or as integral part of the structure is also discussed. Critical assessment of the literature reveals that although protein may contribute to emulsion formation mostly as an anchor for polysaccharides to attach, it is not the determinant factor for the long-term emulsion stability, irrespectively of polysaccharide structure. Interfacial performance of key polysaccharides is also assessed revealing shared characteristics in their modes of adsorption. Conformation of polysaccharides, as affected by the composition of the aqueous solvent needs to be closely controlled, as it seems to be the underlying fundamental cause of stabilisation events and appears to be more important than the constituent polysaccharide sugar-monomers. Finally, polysaccharide adsorption is better understood by regarding them as copolymers, as this approach may assist to better control their properties with the aim to create the next generation biosurfactants.
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Bioactive Algal-Derived Polysaccharides: Multi-Functionalization, Therapeutic Potential and Biomedical Applications.
Muhamad, II, Zulkifli, N, Selvakumaran, SA, Lazim, NAM
Current pharmaceutical design. 2019;(11):1147-1162
Abstract
BACKGROUND In recent decades, there has been an increased interest in the utilization of polysaccharides showing biological activity for various novel applications owing to their biocompatibility, biodegradability, non-toxicity, and some specific therapeutic activities. Increasing studies have started in the past few years to develop algal polysaccharides-based biomaterials for various applications. METHODS Saccharide mapping or enzymatic profiling plays a role in quality control of polysaccharides. Whereby, in vitro and in vivo tests as well as toxicity level discriminating polysaccharides biological activities. Extraction and purification methods are performed in obtaining algal derived polysaccharides followed by chromatographic profiles of their active compounds, structural features, physicochemical properties, and reported biological activities. RESULTS Marine algae are capable of synthesizing Glycosaminoglycans (GAGs) and non-GAGs or GAG mimetics such as sulfated glycans. The cell walls of algae are rich in sulfated polysaccharides, including alginate, carrageenan, ulvan and fucoidan. These biopolymers are widely used algal-derived polysaccharides for biological and biomedical applications due to their biocompatibility and availability. They constitute biochemical compounds that have multi-functionalization, therapeutic potential and immunomodulatory abilities, making them promising bioactive products and biomaterials with a wide range of biomedical applications. CONCLUSION Algal-derived polysaccharides with clearly elucidated compositions/structures, identified cellular activities, as well as desirable physical properties have shown the potential that may create new opportunities. They could be maximally exploited to serve as therapeutic tools such as immunoregulatory agents or drug delivery vehicles. Hence, novel strategies could be applied to tailor multi-functionalization of the polysaccharides from algal species with vast biomedical application potentials.