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Wheat and Rice – Ancient and Modern Cereals
Published in Raymond Cooper, Jeffrey John Deakin, Natural Products of Silk Road Plants, 2020
Raymond Cooper, Jeffrey John Deakin
White rice has had the bran and germ removed through the process of milling. White rice consists of just the endosperm layer, and it is almost entirely composed of starch. White rice grain consists of about 90% carbohydrate, 8% protein, and 2% fat but is low in fiber. Most of the available carbohydrate in rice grain is starch, which is broken down into glucose by enzymes in the human body to provide energy. There are two types of starch in rice grain: amylose and amylopectin, and they are shown in Figure 10.6. Both amylose and amylopectin are large carbohydrate polymers made of glucose molecules. The difference between them is that amylose has a straight chain, while amylopectin is highly branched. These are very large polymeric molecules, made up of a high number and/or a great variety of monosaccharides, and known as polysaccharides. Polysaccharides are a major source of metabolic energy, both for plants and for those animals, which depend on plants for food. Polysaccharides are a component of the energy transport compound, ATP. Starch is also a homopolysaccharide and only very partially soluble in water. Starch is the substance in which plants store their reserves of carbohydrate and is typically found in bulbs, tubers, and seeds. The main commercial sources of starch are found particularly in rice, and in wheat, maize, and potatoes. Starch is hydrolyzed and broken down in human metabolism to provide glucose.
Nutraceuticals and Functional Foods
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
Another homopolysaccharide is pectin, where the repeating subunits are largely methylgalacturonic acid units. It is a jelly-like material that acts as a cellular cement in plants. The linkage between the subunits is also β1-4 bonds. The carboxyl groups become methylated in a seemingly random manner as fruit ripen. Chemically related to pectin is chitin. Chitin is not a plant polysaccharide but is found within the animal kingdom, although not necessarily in humans. It is a β1-4 homopolymer of N-acetyl-glucosamine found in shells or exoskeletons of insects and crustacea. Chitin has been positioned as a dietary ingredient for weight loss.
Seaweeds
Published in Parimelazhagan Thangaraj, Phytomedicine, 2020
L. Stanley Abraham, Vasantharaja Raguraman, R. Thirugnanasambandam, K. M. Smitha, D. Inbakandan, P. Premasudha
The polysaccharides in their sulfated form were abundantly found in the cell wall of seaweeds (Pereira 2018). The sulfated polysaccharides and their derivatives are the complex polymers that differ by their occurrence, structure, and function. They can be extracted from all the classes of macro algae, such as green (Chlorophyceae), red (Rhodophyceae), and brown (Phaeophyceae). The Chlorophyceae such as Monostroma and Ulva sp. result in the production of sulfated polysaccharides viz. ulvan and rhamnan (Liu et al. 2018; Tziveleka et al. 2018; Wang et al. 2018). The Rhodophyceae species of Gracilaria, Hypnea, Laurencia, and Gigartina contribute to the production of galactans and carrageenan (De Almeida et al. 2011). Fucoidans and fucans are brown seaweed’s sulfated polysaccharides, which are abundant in several species such as Sargassum, Padina, Ascophyllum, Nizamuddina, Dictyopteris, Dictyota, and Kjellmaniella (Li et al. 2008). Polysaccharides are biopolymers comprising of same or different monomers to form the essential components for the living system. They have a wide diversity among their composition of monomers, such as direct, interrupted repeat, alternating repeat, block copolymer, branched, and complex repeat. The analysis made on these structures may lead to a better understanding of their function. The polysaccharide is composed of individual sugar units linked with glycosidic linkages, and functional groups. Based on monomeric constituents, it can be divided into a homopolysaccharide, acquired from the same type of sugar residues, and heteropolysaccharide, made from the linkage of different monomers as tabulated in Table 3. The higher and diverse structure of various kinds of polysaccharides tends to possess certain unique biological activities. Specificity augments among these polysaccharides due to their interchain interactions (Eric 2005; Harding et al. 2017). Moreover, the sulfated polysaccharides possess high therapeutic potential as compared to other forms of polysaccharides.
The ancestral stringent response potentiator, DksA has been adapted throughout Salmonella evolution to orchestrate the expression of metabolic, motility, and virulence pathways
Published in Gut Microbes, 2022
Helit Cohen, Boaz Adani, Emiliano Cohen, Bar Piscon, Shalhevet Azriel, Prerak Desai, Heike Bähre, Michael McClelland, Galia Rahav, Ohad Gal-Mor
Another important carbon metabolic pathway in Enterobacteriaceae is glycogen biosynthesis. Glycogen is a branched homopolysaccharide that accumulates in Enterobacteriaceae during growth arrest in the presence of a carbon source excess. In Salmonella and E. coli, glycogen is synthesized by both glycogen synthase GlgA and the branching enzyme GlgB. Glycogen biosynthesis is highly interlinked with a wide range of cellular and physiological processes and is dependent on the expression of the glgBX, glgS, and glgCAP operons.30 RNA-Seq analysis showed that expression of the entire glycogen biosynthesis regulon (glgBXCAPS) decreased in the absence of DksA in E. coli, S. bongori, and S. Typhimurium (Figure 3(c)). In agreement with these data, qRT-PCR experiments showed that glgS and glgX are downregulated by about 9 and 2.5-fold, respectively in the dksA background in S. Typhimurium (Figure 3(b)), indicating that DksA acts as an activator of the glycogen biosynthesis genes.
Enzymatically synthesized exopolysaccharide of a probiotic strain Leuconostoc mesenteroides NTM048 shows adjuvant activity to promote IgA antibody responses
Published in Gut Microbes, 2021
Chiaki Matsuzaki, Yukari Nakashima, Ikuto Endo, Yusuke Tomabechi, Yasuki Higashimura, Saki Itonori, Koji Hosomi, Jun Kunisawa, Kenji Yamamoto, Keiko Hisa
We recently demonstrated that the administration of homopolysaccharide-producing Leuconostoc mesenteroides strain NTM048 cells or EPS produced by this strain (NTM048 EPS) increased intestinal immunoglobulin A (IgA), which is a crucial mucosal barrier.15,23 IgA is secreted onto mucosal surfaces and makes dietary antigens, toxins, and pathogenic microorganisms as targets for attack.24,25In vitro treatment of NTM048 EPS to murine Payer’s patch (PP) cells also stimulated IgA production, indicating that IgA-inducing ability of NTM048 EPS is not caused indirectly by prebiotic effects involving intestinal microbiota but rather that it is the result of a direct stimulant against immune cells.15,26 Furthermore, nasal administration of NTM048 EPS induced an antigen-specific antibody response, demonstrating the possibility for the use of adjuvants for mucosal vaccination.16
Prioritization and characterization of validated biofilm blockers targeting glucosyltransferase C of Streptococcus mutans
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Hazza A. Alhobeira, Mohammed Al Mogbel, Saif Khan, Mahvish Khan, Shafiul Haque, Pallavi Somvanshi, Mohd Wahid, Raju K. Mandal
Biofilm exopolysaccharides (EPS also termed as glucan) are responsible for the growth and colonization of the cariogenic bacteria. Several Streptococci strains including S. mutans are capable of synthesizing EPS. Streptococci EPS are either homopolysaccharides or heteropolysaccharides. Streptococcus mutans secretes an EPS, which is a homopolysaccharide [1]. Glucosyltransferases (also known as Glycosyltransferases Gtfs; i.e. GtfB, GtfC and GtfD) are known to play central role in biofilm EPS (glucan) generation [2–5]. Streptococcus mutans synthesizes at the minimum 3 genetically different Gtfs, and each of them forms a structurally discrete glucan by using sucrose. The special features of the structural and functional organization of Gtfs have been reported earlier [6,7]. GtfB (generally known as GtfI) produces firstly an insoluble glucan with plenty of 1,3-linkages. Whereas, GtfD (GtfS) produces primarily a soluble glucan [8–10]. Unlike above two Gtfs, GtfC (GtfSI) synthesizes an amalgam of insoluble and soluble (having more α-1,6-linkages) forms of glucans. The reaction showing glucan generation catalyzed by GtfC has been presented in Figure 1. Earlier, Ooshima et al. [12] reported that the presence of GtfC intensifies the glucan formation in vitro model, which was later endorsed by the report of Tamesada et al. [13]. GtfC is adsorbed into pellicle, where – when exposed to sucrose, and under in situ condition it synthesizes glucan.