The role of surface carbohydrates on the interaction of microconidia of Trichophyton mentagrophytes with epithelial cells.

PubMed

Esquenazi, Daniele; de Souza, Wanderley; Alviano, Celuta Sales; Rozental, Sonia

2003-03-20

The presence of carbohydrate-binding adhesins on the microconidia of Trichophyton mentagrophytes surface and their role on cellular interactions were investigated. Flow cytometry showed that this fungus recognizes the sugars mannose and galactose. The binding was inhibited by the addition of methyl alpha-D-mannopyranoside and methyl alpha-D-galactopyranoside, and showed higher fluorescence intensity at 37 degrees C than 28 degrees C. Trypsin treatment and heating of the cells reduced the binding, suggesting a (glyco) protein nature of the microconidia adhesin. The interaction of the fungus to Chinese hamster ovary epithelial cells and its glycosylation-deficient mutants demonstrated a higher adhesion index in Lec1 and Lec2 mutants, which express mannose and galactose, respectively, as the terminal carbohydrate on the cell surface. Endocytosed fungi were shown preferentially in Lec2 cells. Addition of the carbohydrates methyl alpha-D-mannopyranoside and methyl alpha-D-galactopyranoside to the interaction medium, pretreatment of Lec1 and Lec2 cells with lectins Concanavalina A and Arachis hypogaea and pretreatment with sodium periodate decreased the adhesion and the endocytic index. Examination of thin section by transmission electron microscopy showed that after fungal ingestion by Lec2 cells the fungi are enclosed in a 'loose'-type vacuole while the other cells are found within a 'tight'-type membrane-bound cytoplasmic vacuole. Our results suggest the occurrence of carbohydrate-specific adhesins on microconidia surface that recognize mannose and galactose. This may have a role in the adhesion process during the infectious process of dermatophytosis.

Multivalent interaction based carbohydrate biosensors for signal amplification

PubMed Central

Wang, Yanyan; Chalagalla, Srinivas; Li, Tiehai; Sun, Xue-long; Zhao, Wei; Wang, Peng; Zeng, Xiangqun

2010-01-01

Multivalent interaction between boronic acids immobilized on Quartz Crystal Microbalance (QCM) sensor surface and the carbohydrates modified Au - nanoparticle (AuNP) has been demonstrated for the development of a sensitive carbohydrate biosensor. Briefly, a boronic acid - containing polymer (boropolymer) as multivalent carbohydrate receptor was oriented immobilized on the cysteamine coated electrode through isourea bond formation. Carbohydrates were conjugated to AuNPs to generate a multivalent carbohydrates moiety to amplify the response signal. Thus, the binding of the carbohydrate conjugated AuNPs to the boropolymer surface are multivalent which could simultaneously increase the binding affinity and specificity. We systematically studied the binding between five carbohydrate conjugated AuNPs and the boropolymer. Our studies show that the associate constant (Ka) was in the order of fucose < glucose < mannose < galactose < maltose. A linear response in the range from 23 µM to 3.83 mM was observed for mannose conjugated AuNPs and the boropolymer recognition elements, with the lower detection limit of 1.5 µM for the carbohydrate analytes. Furthermore, the multivalent binding between carbohydrates and boronic acids are reversible and allow the regeneration of boropolymer surface by using 1M acetic acid so as to sequentially capture and release the carbohydrate analytes. PMID:20863680

Fabrication of Carbohydrate Microarrays by Boronate Formation.

PubMed

Adak, Avijit K; Lin, Ting-Wei; Li, Ben-Yuan; Lin, Chun-Cheng

2017-01-01

The interactions between soluble carbohydrates and/or surface displayed glycans and protein receptors are essential to many biological processes and cellular recognition events. Carbohydrate microarrays provide opportunities for high-throughput quantitative analysis of carbohydrate-protein interactions. Over the past decade, various techniques have been implemented for immobilizing glycans on solid surfaces in a microarray format. Herein, we describe a detailed protocol for fabricating carbohydrate microarrays that capitalizes on the intrinsic reactivity of boronic acid toward carbohydrates to form stable boronate diesters. A large variety of unprotected carbohydrates ranging in structure from simple disaccharides and trisaccharides to considerably more complex human milk and blood group (oligo)saccharides have been covalently immobilized in a single step on glass slides, which were derivatized with high-affinity boronic acid ligands. The immobilized ligands in these microarrays maintain the receptor-binding activities including those of lectins and antibodies according to the structures of their pendant carbohydrates for rapid analysis of a number of carbohydrate-recognition events within 30 h. This method facilitates the direct construction of otherwise difficult to obtain carbohydrate microarrays from underivatized glycans.

A Universal Protocol for Photochemical Covalent Immobilization of Intact Carbohydrates for the Preparation of Carbohydrate Microarrays

PubMed Central

Wang, Huibin; Zhang, Yiming; Yuan, Xun; Chen, Yi; Yan, Mingdi

2010-01-01

A universal photochemical method has been established for the immobilization of intact carbohydrates and their analogues, and for the fabrication of carbohydrate microarrays. The method features the use of perfluorophenyl azide (PFPA)-modified substrates and the photochemical reaction of surface azido groups with printed carbohydrates. Various aldoses, ketoses, non-reducing sugars such as alditols and their derivatives can be directly arrayed on the PFPA-modified chips. The lectin-recognition ability of arrayed mannose, glucose and their oligo- and polysaccharides were confirmed using surface plasmon resonance imaging and laser-induced fluorescence imaging. PMID:21138274

A universal protocol for photochemical covalent immobilization of intact carbohydrates for the preparation of carbohydrate microarrays.

PubMed

Wang, Huibin; Zhang, Yiming; Yuan, Xun; Chen, Yi; Yan, Mingdi

2011-01-19

A universal photochemical method has been established for the immobilization of intact carbohydrates and their analogues, and for the fabrication of carbohydrate microarrays. The method features the use of perfluorophenyl azide (PFPA)-modified substrates and the photochemical reaction of surface azido groups with printed carbohydrates. Various aldoses, ketoses, nonreducing sugars such as alditols, and their derivatives can be directly arrayed on the PFPA-modified chips. The lectin-recognition ability of arrayed mannose, glucose, and their oligo- and polysaccharides were confirmed using surface plasmon resonance imaging and laser-induced fluorescence imaging.

Relationship between Cell Surface Carbohydrates and Intrastrain Variation on Opsonophagocytosis of Streptococcus pneumoniae

PubMed Central

Kim, Jean O.; Romero-Steiner, Sandra; Sørensen, Uffe B. Skov; Blom, Jens; Carvalho, M.; Barnard, S.; Carlone, George; Weiser, Jeffrey N.

1999-01-01

Streptococcus pneumoniae undergoes spontaneous phase variation between a transparent and an opaque colony phenotype, the latter being more virulent in a murine model of sepsis. Opaque pneumococci have previously been shown to express lower amounts of C polysaccharide (cell wall teichoic acid) and in this study were shown to have a higher content of capsular polysaccharide by immunoelectron microscopy. This report then examined the relationship between expression of these two cell surface carbohydrate structures and their relative contribution to the increased virulence of opaque variants. Comparison of genetically related strains showed that the differential content of capsular polysaccharide did not affect the amount of teichoic acid as measured by a capture enzyme-linked immunosorbent assay (ELISA). In contrast, when the teichoic acid structure was altered by replacing choline in the growth medium with structural analogs, the quantity of capsular polysaccharide as measured by a capture ELISA was decreased, demonstrating a linkage in the expression of the two surface carbohydrate structures. A standardized assay was used to assess the relative contribution of cell surface carbohydrates to opsonophagocytosis. The opaque variants required 1.2- to 30-fold more immune human serum to achieve 50% opsonophagocytic killing than did related transparent variants (types 6B and 9V). The opsonophagocytic titer was proportional to the quantity of capsular polysaccharide rather than teichoic acid. The major factor in binding of the opsonin, C-reactive protein (CRP), was also the amount of capsular polysaccharide rather than the teichoic acid ligand. Only for the transparent variant (type 6B), which bound more CRP, was there enhanced opsonophagocytic killing in the presence of this serum protein. Increased expression of capsular polysaccharide, therefore, appeared to be the major factor in the decreased opsonophagocytic killing of opaque pneumococci. PMID:10225891

Analysis of Carbohydrate-Carbohydrate Interactions Using Sugar-Functionalized Silicon Nanoparticles for Cell Imaging.

PubMed

Lai, Chian-Hui; Hütter, Julia; Hsu, Chien-Wei; Tanaka, Hidenori; Varela-Aramburu, Silvia; De Cola, Luisa; Lepenies, Bernd; Seeberger, Peter H

2016-01-13

Protein-carbohydrate binding depends on multivalent ligand display that is even more important for low affinity carbohydrate-carbohydrate interactions. Detection and analysis of these low affinity multivalent binding events are technically challenging. We describe the synthesis of dual-fluorescent sugar-capped silicon nanoparticles that proved to be an attractive tool for the analysis of low affinity interactions. These ultrasmall NPs with sizes of around 4 nm can be used for NMR quantification of coupled sugars. The silicon nanoparticles are employed to measure the interaction between the cancer-associated glycosphingolipids GM3 and Gg3 and the associated kD value by surface plasmon resonance experiments. Cell binding studies, to investigate the biological relevance of these carbohydrate-carbohydrate interactions, also benefit from these fluorescent sugar-capped nanoparticles.

The effect of grain size and surface area on organic matter, lignin and carbohydrate concentration, and molecular compositions in Peru Margin sediments

NASA Astrophysics Data System (ADS)

Bergamaschi, Brian A.; Tsamakis, Elizabeth; Keil, Richard G.; Eglinton, Timothy I.; Montluçon, Daniel B.; Hedges, John I.

1997-03-01

A C-rich sediment sample from the Peru Margin was sorted into nine hydrodynamically-determined grain size fractions to explore the effect of grain size distribution and sediment surface area on organic matter content and composition. The neutral monomeric carbohydrate composition, lignin oxidation product yields, total organic carbon, and total nitrogen contents were determined independently for each size fraction, in addition to sediment surface area and abundance of biogenic opal. The percent organic carbon and percent total nitrogen were strongly related to surface area in these sediments. In turn, the distribution of surface area closely followed mass distribution among the textural size classes, suggesting hydrodynamic controls on grain size also control organic carbon content. Nevertheless, organic compositional distinctions were observed between textural size classes. Total neutral carbohydrate yields in the Peru Margin sediments were found to closely parallel trends in total organic carbon, increasing in abundance among grain size fractions in proportion to sediment surface area. Coincident with the increases in absolute abundance, rhamnose and mannose increased as a fraction of the total carbohydrate yield in concert with surface area, indicating these monomers were preferentially represented in carbohydrates associated with surfaces. Lignin oxidation product yields varied with surface area when normalized to organic carbon, suggesting that the terrestrially-derived component may be diluted by sorption of marine derived material. Lignin-based parameters suggest a separate source for terrestrially derived material associated with sand-size material as opposed to that associated with silts and clays.

Multivalent dendrimeric compounds containing carbohydrates expressed on immune cells inhibit infection by primary isolates of HIV-1

PubMed Central

Borges, Andrew Rosa; Wieczorek, Lindsay; Johnson, Benitra; Benesi, Alan J.; Brown, Bruce K.; Kensinger, Richard D.; Krebs, Fred C.; Wigdahl, Brian; Blumenthal, Robert; Puri, Anu; McCutchan, Francine E.; Birx, Deborah L.; Polonis, Victoria R.; Schengrund, Cara-Lynne

2010-01-01

Specific glycosphingolipids (GSL), found on the surface of target immune cells, are recognized as alternate cell surface receptors by the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein. In this study, the globotriose and 3’-sialyllactose carbohydrate head groups found on two GSL were covalently attached to a dendrimer core to produce two types of unique multivalent carbohydrates (MVC). These MVC inhibited HIV-1 infection of T cell lines and primary peripheral blood mononuclear cells (PBMC) by T cell line-adapted viruses or primary isolates, with IC50s ranging from 0.1 – 7.4 µg/ml. Inhibition of Env-mediated membrane fusion by MVC was also observed using a dye-transfer assay. These carbohydrate compounds warrant further investigation as a potential new class of HIV-1 entry inhibitors. The data presented also shed light on the role of carbohydrate moieties in HIV-1 virus-host cell interactions. PMID:20880566

Analysis of the surfaces of wood tissues and pulp fibers using carbohydrate-binding modules specific for crystalline cellulose and mannan.

PubMed

Filonova, Lada; Kallas, Asa M; Greffe, Lionel; Johansson, Gunnar; Teeri, Tuula T; Daniel, Geoffrey

2007-01-01

Carbohydrate binding modules (CBMs) are noncatalytic substrate binding domains of many enzymes involved in carbohydrate metabolism. Here we used fluorescent labeled recombinant CBMs specific for crystalline cellulose (CBM1(HjCel7A)) and mannans (CBM27(TmMan5) and CBM35(CjMan5C)) to analyze the complex surfaces of wood tissues and pulp fibers. The crystalline cellulose CBM1(HjCel7A) was found as a reliable marker of both bacterially produced and plant G-layer cellulose, and labeling of spruce pulp fibers with CBM1(HjCel7A) revealed a signal that increased with degree of fiber damage. The mannan-specific CBM27(TmMan5) and CBM35(CjMan5C) CBMs were found to be more specific reagents than a monoclonal antibody specific for (1-->4)-beta-mannan/galacto-(1-->4)-beta-mannan for mapping carbohydrates on native substrates. We have developed a quantitative fluorometric method for analysis of crystalline cellulose accumulation on fiber surfaces and shown a quantitative difference in crystalline cellulose binding sites in differently processed pulp fibers. Our results indicated that CBMs provide useful, novel tools for monitoring changes in carbohydrate content of nonuniform substrate surfaces, for example, during wood or pulping processes and possibly fiber biosynthesis.

Hyper-Assembly of Self-Assembled Glycoclusters Mediated by Specific Carbohydrate-Carbohydrate Interactions.

PubMed

Yan, Gengwei; Yamaguchi, Takumi; Suzuki, Tatsuya; Yanaka, Saeko; Sato, Sota; Fujita, Makoto; Kato, Koichi

2017-05-04

Hybridization of a self-assembled, spherical complex with oligosaccharides containing Lewis X, a functional trisaccharide displayed on various cell surfaces, yielded well-defined glycoclusters. The self-assembled glycoclusters exhibited homophilic hyper-assembly in aqueous solution in a Ca 2+ -dependent manner through specific carbohydrate-carbohydrate interactions, offering a structural scaffold for functional biomimetic systems. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of grain size and surface area on organic matter, lignin and carbohydrate concentration, and molecular compositions in Peru Margin sediments

USGS Publications Warehouse

Bergamaschi, B.A.; Tsamakis, E.; Keil, R.G.; Eglinton, T.I.; Montlucon, D.B.; Hedges, J.I.

1997-01-01

A C-rich sediment sample from the Peru Margin was sorted into nine hydrodynamically-determined grain size fractions to explore the effect of grain size distribution and sediment surface area on organic matter content and composition. The neutral monomeric carbohydrate composition, lignin oxidation product yields, total organic carbon, and total nitrogen contents were determined independently for each size fraction, in addition to sediment surface area and abundance of biogenic opal. The percent organic carbon and percent total nitrogen were strongly related to surface area in these sediments. In turn, the distribution of surface area closely followed mass distribution among the textural size classes, suggesting hydrodynamic controls on grain size also control organic carbon content. Nevertheless, organic compositional distinctions were observed between textural size classes. Total neutral carbohydrate yields in the Peru Margin sediments were found to closely parallel trends in total organic carbon, increasing in abundance among grain size fractions in proportion to sediment surface area. Coincident with the increases in absolute abundance, rhamnose and mannose increased as a fraction of the total carbohydrate yield in concert with surface area, indicating these monomers were preferentially represented in carbohydrates associated with surfaces. Lignin oxidation product yields varied with surface area when normalized to organic carbon, suggesting that the terrestrially-derived component may be diluted by sorption of marine derived material. Lignin-based parameters suggest a separate source for terrestrially derived material associated with sand-size material as opposed to that associated with silts and clays. Copyright ?? 1997 Elsevier Science Ltd.

Glycosylation of dengue virus glycoproteins and their interactions with carbohydrate receptors: possible targets for antiviral therapy.

PubMed

Idris, Fakhriedzwan; Muharram, Siti Hanna; Diah, Suwarni

2016-07-01

Dengue virus, an RNA virus belonging to the genus Flavivirus, affects 50 million individuals annually, and approximately 500,000-1,000,000 of these infections lead to dengue hemorrhagic fever or dengue shock syndrome. With no licensed vaccine or specific antiviral treatments available to prevent dengue infection, dengue is considered a major public health problem in subtropical and tropical regions. The virus, like other enveloped viruses, uses the host's cellular enzymes to synthesize its structural (C, E, and prM/M) and nonstructural proteins (NS1-5) and, subsequently, to glycosylate these proteins to produce complete and functional glycoproteins. The structural glycoproteins, specifically the E protein, are known to interact with the host's carbohydrate receptors through the viral proteins' N-glycosylation sites and thus mediate the viral invasion of cells. This review focuses on the involvement of dengue glycoproteins in the course of infection and the virus' exploitation of the host's glycans, especially the interactions between host receptors and carbohydrate moieties. We also discuss the recent developments in antiviral therapies that target these processes and interactions, focusing specifically on the use of carbohydrate-binding agents derived from plants, commonly known as lectins, to inhibit the progression of infection.

Hydration Repulsion between Carbohydrate Surfaces Mediated by Temperature and Specific Ions

PubMed Central

Chen, Hsieh; Cox, Jason R.; Ow, Hooisweng; Shi, Rena; Panagiotopoulos, Athanassios Z.

2016-01-01

Stabilizing colloids or nanoparticles in solution involves a fine balance between surface charges, steric repulsion of coating molecules, and hydration forces against van der Waals attractions. At high temperature and electrolyte concentrations, the colloidal stability of suspensions usually decreases rapidly. Here, we report a new experimental and simulation discovery that the polysaccharide (dextran) coated nanoparticles show ion-specific colloidal stability at high temperature, where we observed enhanced colloidal stability of nanoparticles in CaCl2 solution but rapid nanoparticle-nanoparticle aggregation in MgCl2 solution. The microscopic mechanism was unveiled in atomistic simulations. The presence of surface bound Ca2+ ions increases the carbohydrate hydration and induces strongly polarized repulsive water structures beyond at least three hydration shells which is farther-reaching than previously assumed. We believe leveraging the binding of strongly hydrated ions to macromolecular surfaces represents a new paradigm in achieving absolute hydration and colloidal stability for a variety of materials, particularly under extreme conditions. PMID:27334145

Hydration Repulsion between Carbohydrate Surfaces Mediated by Temperature and Specific Ions

NASA Astrophysics Data System (ADS)

Chen, Hsieh; Cox, Jason R.; Ow, Hooisweng; Shi, Rena; Panagiotopoulos, Athanassios Z.

2016-06-01

Stabilizing colloids or nanoparticles in solution involves a fine balance between surface charges, steric repulsion of coating molecules, and hydration forces against van der Waals attractions. At high temperature and electrolyte concentrations, the colloidal stability of suspensions usually decreases rapidly. Here, we report a new experimental and simulation discovery that the polysaccharide (dextran) coated nanoparticles show ion-specific colloidal stability at high temperature, where we observed enhanced colloidal stability of nanoparticles in CaCl2 solution but rapid nanoparticle-nanoparticle aggregation in MgCl2 solution. The microscopic mechanism was unveiled in atomistic simulations. The presence of surface bound Ca2+ ions increases the carbohydrate hydration and induces strongly polarized repulsive water structures beyond at least three hydration shells which is farther-reaching than previously assumed. We believe leveraging the binding of strongly hydrated ions to macromolecular surfaces represents a new paradigm in achieving absolute hydration and colloidal stability for a variety of materials, particularly under extreme conditions.

Switching of bacterial adhesion to a glycosylated surface by reversible reorientation of the carbohydrate ligand.

PubMed

Weber, Theresa; Chandrasekaran, Vijayanand; Stamer, Insa; Thygesen, Mikkel B; Terfort, Andreas; Lindhorst, Thisbe K

2014-12-22

The surface recognition in many biological systems is guided by the interaction of carbohydrate-specific proteins (lectins) with carbohydrate epitopes (ligands) located within the unordered glycoconjugate layer (glycocalyx) of cells. Thus, for recognition, the respective ligand has to reorient for a successful matching event. Herein, we present for the first time a model system, in which only the orientation of the ligand is altered in a controlled manner without changing the recognition quality of the ligand itself. The key for this orientational control is the embedding into an interfacial system and the use of a photoswitchable mechanical joint, such as azobenzene. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multivalent dendrimeric compounds containing carbohydrates expressed on immune cells inhibit infection by primary isolates of HIV-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosa Borges, Andrew; Wieczorek, Lindsay; Johnson, Benitra

2010-12-05

Specific glycosphingolipids (GSL), found on the surface of target immune cells, are recognized as alternate cell surface receptors by the human immunodeficiency virus type 1 (HIV-1) external envelope glycoprotein. In this study, the globotriose and 3'-sialyllactose carbohydrate head groups found on two GSL were covalently attached to a dendrimer core to produce two types of unique multivalent carbohydrates (MVC). These MVC inhibited HIV-1 infection of T cell lines and primary peripheral blood mononuclear cells (PBMC) by T cell line-adapted viruses or primary isolates, with IC{sub 50}s ranging from 0.1 to 7.4 {mu}g/ml. Inhibition of Env-mediated membrane fusion by MVC wasmore » also observed using a dye-transfer assay. These carbohydrate compounds warrant further investigation as a potential new class of HIV-1 entry inhibitors. The data presented also shed light on the role of carbohydrate moieties in HIV-1 virus-host cell interactions. -- Research Highlights: {yields}Multivalent carbohydrates (MVCs) inhibited infection of PBMCs by HIV-1. {yields}MVCs inhibited infection by T cell line-adapted viruses. {yields}MVCs inhibited infection by primary isolates of HIV-1. {yields}MVCs inhibited Env-mediated membrane fusion.« less

Surrogate target cells expressing surface anti-idiotype antibody for the clinical evaluation of an internalizing CD22-specific antibody.

PubMed

Leung, Shui-On; Gao, Kai; Wang, Guang Yu; Cheung, Benny Ka-Wa; Lee, Kwan-Yeung; Zhao, Qi; Cheung, Wing-Tai; Wang, Jun Zhi

2015-01-01

SM03, a chimeric antibody that targets the B-cell restricted antigen CD22, is currently being clinically evaluated for the treatment of lymphomas and other autoimmune diseases in China. SM03 binding to surface CD22 leads to rapid internalization, making the development of an appropriate cell-based bioassay for monitoring changes in SM03 bioactivities during production, purification, storage, and clinical trials difficult. We report herein the development of an anti-idiotype antibody against SM03. Apart from its being used as a surrogate antigen for monitoring SM03 binding affinities, the anti-idiotype antibody was engineered to express as fusion proteins on cell surfaces in a non-internalizing manner, and the engineered cells were used as novel "surrogate target cells" for SM03. SM03-induced complement-mediated cytotoxicity (CMC) against these "surrogate target cells" proved to be an effective bioassay for monitoring changes in Fc functions, including those resulting from minor structural modifications borne within the Fc-appended carbohydrates. The approach can be generally applied for antibodies that target rapidly internalizing or non-surface bound antigens. The combined use of the anti-idiotype antibody and the surrogate target cells could help evaluate clinical parameters associated with safety and efficacies, and possibly the mechanisms of action of SM03.

The Synthesis and Biological Characterization of Acetal-Free Mimics of the Tumor-Associated Carbohydrate Antigens.

PubMed

Sadraei, Seyed I; Reynolds, Michael R; Trant, John F

2017-01-01

Carcinomas express unique carbohydrates, known as tumor-associated carbohydrate antigens (TACAs), on their surface. These are potential targets for anticancer vaccines; however, to date, no such vaccine has reached the clinic. One factor that may complicate the success of this effort is the lability of the glycosidic bond. Acetal-free carbohydrates are analogues that lack the glycosidic linkage by replacing either the endo or exo oxygen with a methylene. This chapter summarizes the seminal syntheses of the mucin TACAs, provides an overview of common techniques for the synthesis of carbasugars and C-glycosides, reviews the syntheses published to date of acetal-free TACA analogues, and provides an overview of their observed biological activity. We conclude by offering a summation of the challenges remaining to the field biologically and the potential that acetal-free TACAs have of answering several basic questions in carbohydrate immunology. © 2017 Elsevier Inc. All rights reserved.

Targeted identification of metastasis-associated cell-surface sialoglycoproteins in prostate cancer.

PubMed

Yang, Lifang; Nyalwidhe, Julius O; Guo, Siqi; Drake, Richard R; Semmes, O John

2011-06-01

Covalent attachment of carbohydrates to proteins is one of the most common post-translational modifications. At the cell surface, sugar moieties of glycoproteins contribute to molecular recognition events involved in cancer metastasis. We have combined glycan metabolic labeling with mass spectrometry analysis to identify and characterize metastasis-associated cell surface sialoglycoproteins. Our model system used syngeneic prostate cancer cell lines derived from PC3 (N2, nonmetastatic, and ML2, highly metastatic). The metabolic incorporation of AC(4)ManNAz and subsequent specific labeling of cell surface sialylation was confirmed by flow cytometry and confocal microscopy. Affinity isolation of the modified sialic-acid containing cell surface proteins via click chemistry was followed by SDS-PAGE separation and liquid chromatography-tandem MS analysis. We identified 324 proteins from N2 and 372 proteins of ML2. Using conservative annotation, 64 proteins (26%) from N2 and 72 proteins (29%) from ML2 were classified as extracellular or membrane-associated glycoproteins. A selective enrichment of sialoglycoproteins was confirmed. When compared with global proteomic analysis of the same cells, the proportion of identified glycoprotein and cell-surface proteins were on average threefold higher using the selective capture approach. Functional clustering of differentially expressed proteins by Ingenuity Pathway Analysis revealed that the vast majority of glycoproteins overexpressed in the metastatic ML2 subline were involved in cell motility, migration, and invasion. Our approach effectively targeted surface sialoglycoproteins and efficiently identified proteins that underlie the metastatic potential of the ML2 cells.

The influence of surface carbohydrates during in vitro infection of mammalian cells by the dermatophyte Trichophyton rubrum.

PubMed

Esquenazi, Daniele; Alviano, Celuta S; de Souza, Wanderley; Rozental, Sonia

2004-04-01

In order to better understand the role played by surface glycoconjugates during host cell adhesion and endocytosis of Trichophyton rubrum, we looked for the presence of carbohydrate-binding adhesins on the microconidia surface and their role on cellular interaction with epithelial and macrophages cells. The interaction of T. rubrum with chinese hamster ovary epithelial cells and their glycosylation-deficient mutants demonstrated a higher adhesion index in Lec1 and Lec2 mutants, that express mannose and galactose, respectively. Endocytosed fungi were shown preferentially in Lec2 cells. Addition of the carbohydrates to the interaction medium, pretreatment with lectins and with sodium periodate decreased the adhesion and endocytic index for all mutants. The ability of the fungus to penetrate into mammalian cells was confirmed in experiments using macrophages treated with cytochalasin D. Flow cytometric analysis showed that this fungus recognizes mannose and galactose. The binding was inhibited by the addition of methyl alpha-D-mannopyranoside and methyl alpha-D-galactopyranoside, and showed higher fluorescence intensity at 37 than at 28 degrees C. Trypsin treatment and heating of the cells reduced the binding, suggesting a (glyco) protein nature for the microconidia adhesins. The presence of lectin-like molecules in fungus cell could be observed by scanning electron microscopy of the fungus incubated with colloidal-gold labeled neoglycoproteins. Our results suggest that T. rubrum has the ability to invade mammalian cells and expresses carbohydrate-specific adhesins on microconidia surface that recognize mannose and galactose. These adhesins may play an important role on the adhesion and invasion of the fungus during the infectious process of dermatophytosis.

Carbohydrate Recognition by Boronolectins, Small Molecules, and Lectins

PubMed Central

Jin, Shan; Cheng, Yunfeng; Reid, Suazette; Li, Minyong; Wang, Binghe

2009-01-01

Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents. However, this potential is far from being realized. One key issue is the difficulty in the development of “binders” capable of specific recognition of carbohydrates of biological relevance. This review discusses systematically the general approaches that are available in developing carbohydrate sensors and “binders/receptors,” and their applications. The focus is on discoveries during the last five years. PMID:19291708

Targeting C-type lectin receptors: a high-carbohydrate diet for dendritic cells to improve cancer vaccines

PubMed Central

van Dinther, Dieke; Stolk, Dorian A.; van de Ven, Rieneke; van Kooyk, Yvette; de Gruijl, Tanja D.; den Haan, Joke M. M.

2017-01-01

There is a growing understanding of why certain patients do or do not respond to checkpoint inhibition therapy. This opens new opportunities to reconsider and redevelop vaccine strategies to prime an anticancer immune response. Combination of such vaccines with checkpoint inhibitors will both provide the fuel and release the brake for an efficient anticancer response. Here, we discuss vaccine strategies that use C-type lectin receptor (CLR) targeting of APCs, such as dendritic cells and macrophages. APCs are a necessity for the priming of antigen-specific cytotoxic and helper T cells. Because CLRs are natural carbohydrate-recognition receptors highly expressed by multiple subsets of APCs and involved in uptake and processing of Ags for presentation, these receptors seem particularly interesting for targeting purposes. PMID:28729358

Role of Carbohydrate in Glycoprotein Traffic and Secretion

DTIC Science & Technology

1988-01-01

synthesized in normal amounts but accumu- lated intracellularly, with transport to the cell surface being greatly de - layed. Glycoprotein E2 isolated from...UNcLA ,F E 2 Role of Carbohydrate in Glycoprotein Traffic and Secretion JAMES B. PARENT I. Introduction I!. Evidence for Intracellular Transport Signals...Ill. Oligosaccharide Biosynthesis IV. Role of Carbohydrate in Protein Solubility. Structure, and Stability V. Evidence for Carbohydrate Transport

Targeted Identification of Metastasis-associated Cell-surface Sialoglycoproteins in Prostate Cancer*

PubMed Central

Yang, Lifang; Nyalwidhe, Julius O.; Guo, Siqi; Drake, Richard R.; Semmes, O. John

2011-01-01

Covalent attachment of carbohydrates to proteins is one of the most common post-translational modifications. At the cell surface, sugar moieties of glycoproteins contribute to molecular recognition events involved in cancer metastasis. We have combined glycan metabolic labeling with mass spectrometry analysis to identify and characterize metastasis-associated cell surface sialoglycoproteins. Our model system used syngeneic prostate cancer cell lines derived from PC3 (N2, nonmetastatic, and ML2, highly metastatic). The metabolic incorporation of AC4ManNAz and subsequent specific labeling of cell surface sialylation was confirmed by flow cytometry and confocal microscopy. Affinity isolation of the modified sialic-acid containing cell surface proteins via click chemistry was followed by SDS-PAGE separation and liquid chromatography-tandem MS analysis. We identified 324 proteins from N2 and 372 proteins of ML2. Using conservative annotation, 64 proteins (26%) from N2 and 72 proteins (29%) from ML2 were classified as extracellular or membrane-associated glycoproteins. A selective enrichment of sialoglycoproteins was confirmed. When compared with global proteomic analysis of the same cells, the proportion of identified glycoprotein and cell-surface proteins were on average threefold higher using the selective capture approach. Functional clustering of differentially expressed proteins by Ingenuity Pathway Analysis revealed that the vast majority of glycoproteins overexpressed in the metastatic ML2 subline were involved in cell motility, migration, and invasion. Our approach effectively targeted surface sialoglycoproteins and efficiently identified proteins that underlie the metastatic potential of the ML2 cells. PMID:21447706

Multifunctional cellulase catalysis targeted by fusion to different carbohydrate-binding modules

DOE PAGES

Walker, Johnnie A.; Takasuka, Taichi E.; Deng, Kai; ...

2015-12-21

Carbohydrate binding modules (CBMs) bind polysaccharides and help target glycoside hydrolases catalytic domains to their appropriate carbohydrate substrates. To better understand how CBMs can improve cellulolytic enzyme reactivity, representatives from each of the 18 families of CBM found in Ruminoclostridium thermocellum were fused to the multifunctional GH5 catalytic domain of CelE (Cthe_0797, CelEcc), which can hydrolyze numerous types of polysaccharides including cellulose, mannan, and xylan. Since CelE is a cellulosomal enzyme, none of these fusions to a CBM previously existed. CelEcc_CBM fusions were assayed for their ability to hydrolyze cellulose, lichenan, xylan, and mannan. Several CelEcc_CBM fusions showed enhanced hydrolyticmore » activity with different substrates relative to the fusion to CBM3a from the cellulosome scaffoldin, which has high affinity for binding to crystalline cellulose. Additional binding studies and quantitative catalysis studies using nanostructure-initiator mass spectrometry (NIMS) were carried out with the CBM3a, CBM6, CBM30, and CBM44 fusion enzymes. In general, and consistent with observations of others, enhanced enzyme reactivity was correlated with moderate binding affinity of the CBM. Numerical analysis of reaction time courses showed that CelEcc_CBM44, a combination of a multifunctional enzyme domain with a CBM having broad binding specificity, gave the fastest rates for hydrolysis of both the hexose and pentose fractions of ionic-liquid pretreated switchgrass. In conclusion, we have shown that fusions of different CBMs to a single multifunctional GH5 catalytic domain can increase its rate of reaction with different pure polysaccharides and with pretreated biomass. This fusion approach, incorporating domains with broad specificity for binding and catalysis, provides a new avenue to improve reactivity of simple combinations of enzymes within the complexity of plant biomass.« less

Functional interaction analysis of GM1-related carbohydrates and Vibrio cholerae toxins using carbohydrate microarray.

PubMed

Kim, Chang Sup; Seo, Jeong Hyun; Cha, Hyung Joon

2012-08-07

The development of analytical tools is important for understanding the infection mechanisms of pathogenic bacteria or viruses. In the present work, a functional carbohydrate microarray combined with a fluorescence immunoassay was developed to analyze the interactions of Vibrio cholerae toxin (ctx) proteins and GM1-related carbohydrates. Ctx proteins were loaded onto the surface-immobilized GM1 pentasaccharide and six related carbohydrates, and their binding affinities were detected immunologically. The analysis of the ctx-carbohydrate interactions revealed that the intrinsic selectivity of ctx was GM1 pentasaccharide ≫ GM2 tetrasaccharide > asialo GM1 tetrasaccharide ≥ GM3trisaccharide, indicating that a two-finger grip formation and the terminal monosaccharides play important roles in the ctx-GM1 interaction. In addition, whole cholera toxin (ctxAB(5)) had a stricter substrate specificity and a stronger binding affinity than only the cholera toxin B subunit (ctxB). On the basis of the quantitative analysis, the carbohydrate microarray showed the sensitivity of detection of the ctxAB(5)-GM1 interaction with a limit-of-detection (LOD) of 2 ng mL(-1) (23 pM), which is comparable to other reported high sensitivity assay tools. In addition, the carbohydrate microarray successfully detected the actual toxin directly secreted from V. cholerae, without showing cross-reactivity to other bacteria. Collectively, these results demonstrate that the functional carbohydrate microarray is suitable for analyzing toxin protein-carbohydrate interactions and can be applied as a biosensor for toxin detection.

Computational modeling of carbohydrate recognition in protein complex

NASA Astrophysics Data System (ADS)

Ishida, Toyokazu

2017-11-01

To understand the mechanistic principle of carbohydrate recognition in proteins, we propose a systematic computational modeling strategy to identify complex carbohydrate chain onto the reduced 2D free energy surface (2D-FES), determined by MD sampling combined with QM/MM energy corrections. In this article, we first report a detailed atomistic simulation study of the norovirus capsid proteins with carbohydrate antigens based on ab initio QM/MM combined with MD-FEP simulations. The present result clearly shows that the binding geometries of complex carbohydrate antigen are determined not by one single, rigid carbohydrate structure, but rather by the sum of averaged conformations mapped onto the minimum free energy region of QM/MM 2D-FES.

Boosting immunity to small tumor-associated carbohydrates with bacteriophage qβ capsids.

PubMed

Yin, Zhaojun; Comellas-Aragones, Marta; Chowdhury, Sudipa; Bentley, Philip; Kaczanowska, Katarzyna; Benmohamed, Lbachir; Gildersleeve, Jeffrey C; Finn, M G; Huang, Xuefei

2013-01-01

The development of an effective immunotherapy is an attractive strategy toward cancer treatment. Tumor associated carbohydrate antigens (TACAs) are overexpressed on a variety of cancer cell surfaces, which present tempting targets for anticancer vaccine development. However, such carbohydrates are often poorly immunogenic. To overcome this challenge, we show here that the display of a very weak TACA, the monomeric Tn antigen, on bacteriophage Qβ virus-like particles elicits powerful humoral responses to the carbohydrate. The effects of adjuvants, antigen display pattern, and vaccine dose on the strength and subclasses of antibody responses were established. The local density of antigen rather than the total amount of antigen administered was found to be crucial for induction of high Tn-specific IgG titers. The ability to display antigens in an organized and high density manner is a key advantage of virus-like particles such as Qβ as vaccine carriers. Glycan microarray analysis showed that the antibodies generated were highly selective toward Tn antigens. Furthermore, Qβ elicited much higher levels of IgG antibodies than other types of virus-like particles, and the IgG antibodies produced reacted strongly with the native Tn antigens on human leukemia cells. Thus, Qβ presents a highly attractive platform for the development of carbohydrate-based anticancer vaccines.

Surface Behavior of BSA/Water/Carbohydrate Systems from Molecular Polarizability Measurements.

PubMed

Alvarado, Ysaías J; Ferrebuz, Atilio; Paz, Jose Luis; Rodríguez-Lugo, Patricia; Restrepo, Jelem; Romero, Freddy; Fernández-Acuña, Jaqueline; Williams, Yhan O'Neil; Toro-Mendoza, Jhoan

2018-04-19

The effect of the presence of glucose and sucrose on the nonintrinsic contribution to partial molar volume ⟨Θ⟩ ni of bovine serum albumin (BSA) is determined by means of static and dynamic electronic polarizability measurements. For that aim, a combined strategy based on high-resolution refractometry, high exactitude densitometry, and synchronous fluorescence spectroscopy is applied. Both static and dynamic mean electronic molecular polarizability values are found to be sensitive to the presence of glucose. In the case of sucrose, the polarizability of BSA is not appreciably affected. In fact, our results revealed that the electronic changes observed occurred without a modification of the native conformation of BSA. On the contrary, a nonmonotonous behavior with the concentration is observed in presence of glucose. These results advocate the influence of the electronic polarization on the repulsive and attractive protein-carbohydrate interactions. An analysis using the scaled particle theory indicates that the accumulation of glucose on the protein surface promotes dehydration. Inversely, hydration and preferential exclusion occur in the vicinity of the protein surface for sucrose-enriched systems.

Hemiuroid trematode sporocysts are undetected by hemocytes of their intermediate host, the ark cockle Anadara trapezia: potential role of surface carbohydrates in successful parasitism.

PubMed

Kawasaki, Minami; Delamare-Deboutteville, Jerome; Dang, Cecile; Barnes, Andrew C

2013-12-01

In order to establish a successful relationship with their hosts, parasites must subvert or evade immune defences. Cockle Anadara trapezia and Sydney Rock oyster (SRO) Saccostrea glomerata live in the same location but only ark cockles are infected by sporocysts of hemiuroid trematode. This provides an opportunity to explore differing interactions between the parasite and the immune system of susceptible and refractive hosts. Rapid migration and encapsulation of sporocysts was observed by SRO hemocytes but not by cockle hemocytes. This migration/encapsulation was inhibited by N-acetylglucosamine or N-acetylgalactosamine but not by the other sugars, implicating specific surface carbohydrates in immune detection. Effector responses of hemocytes were investigated in vitro in terms of production of reactive oxygen production (ROS). Hemocytes of both species strongly reacted to Zymosan, but only SRO hemocytes responded to live sporocysts. Neither species' hemocytes produced ROS in the presence of dead/fixed sporocysts, and there was no suppression of Zymosan-induced respiratory burst by sporocysts. This suggests that immune escape is mediated by avoiding encapsulation, perhaps through molecular mimicry. Membrane-shaving with proteases indicated that sporocyst surface proteins are not a key factors in hemocytic detection. Surface carbohydrates of SRO and cockle hemocytes and of sporocysts were profiled with a panel of biotinylated lectins. This revealed substantial differences between cockle and SRO hemocytes, but greater similarity between cockle hemocytes and sporocysts. Results suggest that surface carbohydrates play an integral role in hemocyte immunorecognition and that surface carbohydrate molecular mimicry is a potential strategy for immune evasion in cockles by hemiuroid trematode sporocysts. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Real-time and label-free analysis of binding thermodynamics of carbohydrate-protein interactions on unfixed cancer cell surfaces using a QCM biosensor

PubMed Central

Li, Xueming; Song, Siyu; Shuai, Qi; Pei, Yihan; Aastrup, Teodor; Pei, Yuxin; Pei, Zhichao

2015-01-01

A novel approach to the study of binding thermodynamics and kinetics of carbohydrate-protein interactions on unfixed cancer cell surfaces using a quartz crystal microbalance (QCM) biosensor was developed, in which binding events take place at the cell surface, more closely mimicking a biologically relevant environment. In this study, colon adenocarcinoma cells (KM-12) and ovary adenocarcinoma cells (SKOV-3) grew on the optimized polystyrene-coated biosensor chip without fixation. The association and dissociation between the cell surface carbohydrates and a range of lectins, including WGA, Con A, UEA-I, GS-II, PNA and SBA, were monitored in real time and without label for evaluation of cell surface glycosylation. Furthermore, the thermodynamic and kinetic parameters of the interaction between lectins and cell surface glycan were studied, providing detailed information about the interactions, such as the association rate constant, dissociation rate constant, affinity constant, as well as the changes of entropy, enthalpy and Gibbs free energy. This application provides an insight into the cell surface glycosylation and the complex molecular recognition on the intact cell surface, which may have impacts on disease diagnosis and drug discovery. PMID:26369583

Characterizing carbohydrate-protein interactions by NMR

PubMed Central

Bewley, Carole A.; Shahzad-ul-Hussan, Syed

2013-01-01

Interactions between proteins and soluble carbohydrates and/or surface displayed glycans are central to countless recognition, attachment and signaling events in biology. The physical chemical features associated with these binding events vary considerably, depending on the biological system of interest. For example, carbohydrate-protein interactions can be stoichiometric or multivalent, the protein receptors can be monomeric or oligomeric, and the specificity of recognition can be highly stringent or rather promiscuous. Equilibrium dissociation constants for carbohydrate binding are known to vary from micromolar to millimolar, with weak interactions being far more prevalent; and individual carbohydrate binding sites can be truly symmetrical or merely homologous, and hence, the affinities of individual sites within a single protein can vary, as can the order of binding. Several factors, including the weak affinities with which glycans bind their protein receptors, the dynamic nature of the glycans themselves, and the non-equivalent interactions among oligomeric carbohydrate receptors, have made NMR an especially powerful tool for studying and defining carbohydrate-protein interactions. Here we describe those NMR approaches that have proven to be the most robust in characterizing these systems, and explain what type of information can (or cannot) be obtained from each. Our goal is to provide to the reader the information necessary for selecting the correct experiment or sets of experiments to characterize their carbohydrate-protein interaction of interest. PMID:23784792

Carbohydrate recognition by the antiviral lectin cyanovirin-N

PubMed Central

Fujimoto, Yukiji K.; Green, David F.

2012-01-01

Cyanovirin-N is a cyanobacterial lectin with potent antiviral activity, and has been the focus of extensive pre-clinical investigation as a potential prophylactic for the prevention of the sexual transmission of the human immunodeficiency virus (HIV). Here we present a detailed analysis of carbohydrate recognition by this important protein, using a combination of computational methods, including extensive molecular dynamics simulations and Molecular-Mechanics/ Poisson–Boltzmann/Surface-Area (MM/PBSA) energetic analysis. The simulation results strongly suggest that the observed tendency of wildtype CVN to form domain-swapped dimers is the result of a previously unidentified cis-peptide bond present in the monomeric state. The energetic analysis additionally indicates that the highest-affinity ligand for CVN characterized to date (α-Man-(1,2)-α-Man-(1,2)-α-Man) is recognized asymmetrically by the two binding sites. Finally, we are able to provide a detailed map of the role of all binding site functional groups (both backbone and side chain) to various aspects of molecular recognition: general affinity for cognate ligands, specificity for distinct oligosaccharide targets and the asymmetric recognition of α-Man-(1,2)-α-Man-(1,2)-α-Man. Taken as a whole, these results complement past experimental characterization (both structural and thermodynamic) to provide the most complete understanding of carbohydrate recognition by CVN to date. The results also provide strong support for the application of similar approaches to the understanding of other protein–carbohydrate complexes. PMID:23057413

Carbohydrate and exercise performance: the role of multiple transportable carbohydrates.

PubMed

Jeukendrup, Asker E

2010-07-01

Carbohydrate feeding has been shown to be ergogenic, but recently substantial advances have been made in optimizing the guidelines for carbohydrate intake during prolonged exercise. It was found that limitations to carbohydrate oxidation were in the absorptive process most likely because of a saturation of carbohydrate transporters. By using a combination of carbohydrates that use different intestinal transporters for absorption it was shown that carbohydrate delivery and oxidation could be increased. Studies demonstrated increases in exogenous carbohydrate oxidation rates of up to 65% of glucose: fructose compared with glucose only. Exogenous carbohydrate oxidation rates reach values of 1.75 g/min whereas previously it was thought that 1 g/min was the absolute maximum. The increased carbohydrate oxidation with multiple transportable carbohydrates was accompanied by increased fluid delivery and improved oxidation efficiency, and thus the likelihood of gastrointestinal distress may be diminished. Studies also demonstrated reduced fatigue and improved exercise performance with multiple transportable carbohydrates compared with a single carbohydrate. Multiple transportable carbohydrates, ingested at high rates, can be beneficial during endurance sports in which the duration of exercise is 3 h or more.

A platform to screen for C-type lectin receptor-binding carbohydrates and their potential for cell-specific targeting and immune modulation.

PubMed

Maglinao, Maha; Eriksson, Magdalena; Schlegel, Mark K; Zimmermann, Stephanie; Johannssen, Timo; Götze, Sebastian; Seeberger, Peter H; Lepenies, Bernd

2014-02-10

Myeloid C-type lectin receptors (CLRs) in innate immunity represent a superfamily of pattern recognition receptors that recognize carbohydrate structures on pathogens and self-antigens. The primary interaction of an antigen-presenting cell and a pathogen shapes the following immune response. Therefore, the identification of CLR ligands that can either enhance or modulate the immune response is of interest. We have developed a screening platform based on glycan arrays to identify immune modulatory carbohydrate ligands of CLRs. A comprehensive library of CLRs was expressed by fusing the extracellular part of each respective CLR, the part containing the carbohydrate-recognition domain (CRD), to the Fc fragment of human IgG1 molecules. CLR-Fc fusion proteins display the CRD in a dimeric form, are properly glycosylated, and can be detected by a secondary antibody with a conjugated fluorophore. Thus, they are valuable tools for high-throughput screening. We were able to identify novel carbohydrate binders of CLRs using the glycan array technology. These CLR-binding carbohydrates were then covalently attached to the model antigen ovalbumin. The ovalbumin neoglycoconjugates were used in a dendritic cell/T cell co-culture assay to stimulate transgenic T cells in vitro. In addition, mice were immunized with these conjugates to analyze the immune modulatory properties of the CLR ligands in vivo. The CLR ligands induced an increased Th1 cytokine production in vitro and modulated the humoral response in vivo. The platform described here allows for the identification of CLR ligands, as well as the evaluation of each ligand's cell-specific targeting and immune modulatory properties. Copyright © 2013 Elsevier B.V. All rights reserved.

Recent progress in chemical and chemoenzymatic synthesis of carbohydrates.

PubMed

Muthana, Saddam; Cao, Hongzhi; Chen, Xi

2009-12-01

The important roles that carbohydrates play in biological processes and their potential application in diagnosis, therapeutics, and vaccine development have made them attractive synthetic targets. Despite ongoing challenges, tremendous progresses have been made in recent years for the synthesis of carbohydrates. The chemical glycosylation methods have become more sophisticated and the synthesis of oligosaccharides has become more predictable. Simplified one-pot glycosylation strategy and automated synthesis are increasingly used to obtain biologically important glycans. On the other hand, chemoenzymatic synthesis continues to be a powerful alternative for obtaining complex carbohydrates. This review highlights recent progress in chemical and chemoenzymatic synthesis of carbohydrates with a particular focus on the methods developed for the synthesis of oligosaccharides, polysaccharides, glycolipids, and glycosylated natural products.

Recent Progress in Chemical and Chemoenzymatic Synthesis of Carbohydrates

PubMed Central

Muthana, Saddam; Cao, Hongzhi; Chen, Xi

2011-01-01

Summary The important roles that carbohydrates play in biological processes and their potential application in diagnosis, therapeutics, and vaccine development have made them attractive synthetic targets. Despite ongoing challenges, tremendous progresses have been made in recent years for the synthesis of carbohydrates. The chemical glycosylation methods have become more sophisticated and the synthesis of oligosaccharides has become more predictable. Simplified one-pot glycosylation strategy and automated synthesis are increasingly used to obtain biologically important glycans. On the other hand, chemoenzymatic synthesis continues to be a powerful alternative for obtaining complex carbohydrates. This review highlights recent progress in chemical and chemoenzymatic synthesis of carbohydrates with a particular focus on the methods developed for the synthesis of oligosaccharides, polysaccharides, glycolipids, and glycosylated natural products. PMID:19833544

Reuteran and levan as carbohydrate sinks in transgenic sugarcane.

PubMed

Bauer, Rolene; Basson, Carin E; Bekker, Jan; Eduardo, Iban; Rohwer, Johann M; Uys, Lafras; van Wyk, Johannes H; Kossmann, Jens

2012-12-01

The present study reports the effect of high molecular weight bacterial fructan (levan) and glucan (reuteran) on growth and carbohydrate partitioning in transgenic sugarcane plants. These biopolymers are products of bacterial glycosyltransferases, enzymes that catalyze the polymerization of glucose or fructose residues from sucrose. Constructs, targeted to different subcellular compartments (cell wall and cytosol) and driven by the Cauliflower mosaic virus-35S: maize-ubiquitin promoter, were introduced into sugarcane by biolistic transformation. Polysaccharide accumulation severely affected growth of callus suspension cultures. Regeneration of embryonic callus tissue into plants proved problematic for cell wall-targeted lines. When targeted to the cytosol, only plants with relative low levels of biopolymer accumulation survived. In internodal stalk tissue that accumulate reuteran (max 0.03 mg/g FW), sucrose content (ca 60 mg/g FW) was not affected, while starch content (<0.4 mg/g FW) was increased up to four times. Total carbohydrate content was not significantly altered. On the other hand, starch and sucrose levels were significantly reduced in plants accumulating levan (max 0.01 mg/g FW). Heterologous expression resulted in a reduction in total carbohydrate assimilation rather than a simple diversion by competition for substrate.

Dynamic Fluctuations of Protein-Carbohydrate Interactions Promote Protein Aggregation

PubMed Central

Voynov, Vladimir; Chennamsetty, Naresh; Kayser, Veysel; Helk, Bernhard; Forrer, Kurt; Zhang, Heidi; Fritsch, Cornelius; Heine, Holger; Trout, Bernhardt L.

2009-01-01

Protein-carbohydrate interactions are important for glycoprotein structure and function. Antibodies of the IgG class, with increasing significance as therapeutics, are glycosylated at a conserved site in the constant Fc region. We hypothesized that disruption of protein-carbohydrate interactions in the glycosylated domain of antibodies leads to the exposure of aggregation-prone motifs. Aggregation is one of the main problems in protein-based therapeutics because of immunogenicity concerns and decreased efficacy. To explore the significance of intramolecular interactions between aromatic amino acids and carbohydrates in the IgG glycosylated domain, we utilized computer simulations, fluorescence analysis, and site-directed mutagenesis. We find that the surface exposure of one aromatic amino acid increases due to dynamic fluctuations. Moreover, protein-carbohydrate interactions decrease upon stress, while protein-protein and carbohydrate-carbohydrate interactions increase. Substitution of the carbohydrate-interacting aromatic amino acids with non-aromatic residues leads to a significantly lower stability than wild type, and to compromised binding to Fc receptors. Our results support a mechanism for antibody aggregation via decreased protein-carbohydrate interactions, leading to the exposure of aggregation-prone regions, and to aggregation. PMID:20037630

Carbohydrate-protein interactions: molecular modeling insights.

PubMed

Pérez, Serge; Tvaroška, Igor

2014-01-01

The article reviews the significant contributions to, and the present status of, applications of computational methods for the characterization and prediction of protein-carbohydrate interactions. After a presentation of the specific features of carbohydrate modeling, along with a brief description of the experimental data and general features of carbohydrate-protein interactions, the survey provides a thorough coverage of the available computational methods and tools. At the quantum-mechanical level, the use of both molecular orbitals and density-functional theory is critically assessed. These are followed by a presentation and critical evaluation of the applications of semiempirical and empirical methods: QM/MM, molecular dynamics, free-energy calculations, metadynamics, molecular robotics, and others. The usefulness of molecular docking in structural glycobiology is evaluated by considering recent docking- validation studies on a range of protein targets. The range of applications of these theoretical methods provides insights into the structural, energetic, and mechanistic facets that occur in the course of the recognition processes. Selected examples are provided to exemplify the usefulness and the present limitations of these computational methods in their ability to assist in elucidation of the structural basis underlying the diverse function and biological roles of carbohydrates in their dialogue with proteins. These test cases cover the field of both carbohydrate biosynthesis and glycosyltransferases, as well as glycoside hydrolases. The phenomenon of (macro)molecular recognition is illustrated for the interactions of carbohydrates with such proteins as lectins, monoclonal antibodies, GAG-binding proteins, porins, and viruses. © 2014 Elsevier Inc. All rights reserved.

Abuse potential of carbohydrates for overweight carbohydrate cravers

PubMed Central

Spring, Bonnie; Schneider, Kristin; Smith, Malaina; Kendzor, Darla; Appelhans, Bradley; Hedeker, Donald; Pagoto, Sherry

2010-01-01

Rationale The long-rejected construct of food addiction is undergoing re-examination. Objectives . To evaluate whether a novel carbohydrate food shows abuse potential for rigorously defined carbohydrate cravers, as evidenced by selective self-administration and mood enhancement during double-blind discrimination testing. Methods Discrete trials choice testing was performed with 61 overweight (BMI m=27.64, SD=2.59) women (ages 18–45; 19.70% African American) whose diet records showed >4 weekly afternoon/evening emotional eating episodes confined to snacks with carbohydrate:protein ≥ 6:1. After being induced into a sad mood, participants were exposed, double-blind and in counterbalanced order, to taste-matched carbohydrate and protein beverages. They were asked to choose and self-administer the drink that made them feel better. Results Women overwhelmingly chose the carbohydrate beverage, even though blinded. Mixed-effects regression modeling, controlling for beverage order, revealed greater liking and greater reduction in dysphoria following the carbohydrate beverage compared to the protein beverage, but no differential effect on vigor. Conclusion For women who crave them, carbohydrates appear to display abuse potential, plausibly contributing to overconsumption and overweight. PMID:18273603

Understanding carbohydrate-carbohydrate interactions by means of glyconanotechnology.

PubMed

de la Fuente, Jesus M; Penadés, Soledad

2004-01-01

Carbohydrate-carbohydrate interaction is a reliable and versatile mechanism for cell adhesion and recognition. Glycosphingolipid (GSL) clusters at the cell membrane are mainly involved in this interaction. To investigate carbohydrate-carbohydrate interaction an integrated strategy (Glyconanotechnology) was developed. This strategy includes polyvalent tools (gold glyconanoparticles) mimicking GSL clustering at the cell membrane as well as analytical techniques such as AFM, TEM, and SPR to evaluate the interactions. The results obtained by means of this strategy and current status are presented.

Boronic acids for fluorescence imaging of carbohydrates.

PubMed

Sun, Xiaolong; Zhai, Wenlei; Fossey, John S; James, Tony D

2016-02-28

"Fluorescence imaging" is a particularly exciting and rapidly developing area of research; the annual number of publications in the area has increased ten-fold over the last decade. The rapid increase of interest in fluorescence imaging will necessitate the development of an increasing number of molecular receptors and binding agents in order to meet the demand in this rapidly expanding area. Carbohydrate biomarkers are particularly important targets for fluorescence imaging given their pivotal role in numerous important biological events, including the development and progression of many diseases. Therefore, the development of new fluorescent receptors and binding agents for carbohydrates is and will be increasing in demand. This review highlights the development of fluorescence imaging agents based on boronic acids a particularly promising class of receptors given their strong and selective binding with carbohydrates in aqueous media.

Carbohydrate coated, folate functionalized colloidal graphene as a nanocarrier for both hydrophobic and hydrophilic drugs.

PubMed

Maity, Amit Ranjan; Chakraborty, Atanu; Mondal, Avijit; Jana, Nikhil R

2014-03-07

Although graphene based drug delivery has gained significant recent interest, the synthesis of colloidal graphene based nanocarriers with high drug loading capacities and with targeting ligands at the outer surface is a challenging issue. We have synthesized carbohydrate coated and folate functionalized colloidal graphene which can be used as a nanocarrier for a wide variety of hydrophobic and hydrophilic drugs. The synthesized colloidal graphene is loaded with paclitaxol, camptothecin, doxorubicin, curcumin and used for their targeted delivery to cancer cells. We demonstrate that this drug loaded functional graphene nanocarrier can successfully deliver drugs into target cells and offers an enhanced therapeutic performance. The reported approach can be extended to the cellular delivery of other hydrophobic and hydrophilic drugs and the simultaneous delivery of multiple drugs.

Carbohydrates

MedlinePlus

... include sugars added during food processing and refining. Complex carbohydrates include whole grain breads and cereals, starchy vegetables and legumes. Many of the complex carbohydrates are good sources of fiber. For a healthy ...

Defined presentation of carbohydrates on a duplex DNA scaffold.

PubMed

Schlegel, Mark K; Hütter, Julia; Eriksson, Magdalena; Lepenies, Bernd; Seeberger, Peter H

2011-12-16

A new method for the spatially defined alignment of carbohydrates on a duplex DNA scaffold is presented. The use of an N-hydroxysuccinimide (NHS)-ester phosphoramidite along with carbohydrates containing an alkylamine linker allows for on-column labeling during solid-phase oligonucleotide synthesis. This modification method during solid-phase synthesis only requires the use of minimal amounts of complex carbohydrates. The covalently attached carbohydrates are presented in the major groove of the B-form duplex DNA as potential substrates for murine type II C-type lectin receptors mMGL1 and mMGL2. CD spectroscopy and thermal melting revealed only minimal disturbance of the overall helical structure. Surface plasmon resonance and cellular uptake studies with bone-marrow-derived dendritic cells were used to assess the capability of these carbohydrate-modified duplexes to bind to mMGL receptors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Current concepts of digestion and absorption of carbohydrates].

PubMed

Luz, S dos S; de Campos, P L; Ribeiro, S M; Tirapegui, J

1997-01-01

The aim of this paper is to review recent aspects of digestion and absorption of carbohydrates that are the main source of energy in human diets. Recent researches have found that starch is not largely hydrolysed and absorbed in the small bowel but one part of it is resistant to digestion. Several food factors may be responsible for digestion and absorption velocity and totality of carbohydrates. Therefore, carbohydrate classification must be based not only on molecular size to express the real carbohydrates utilization as an energy source by humans. In agreement with molecular size of carbohydrate, its classification can be: a) monosaccharides; b) disaccharides; c) oligosaccharides; d) polysaccharides. In agreement with carbohydrate digestibility or availability, its classification can be: a) digestible carbohydrates; b) undigestable carbohydrates (NSP). Carbohydrate digestibility can be altered by several factors like: Intrinsic factors: a) physical structure; b) molecular physical distribution; c) physical state of food; d) food antinutrients. Extrinsics factors: a) chewing; b) transit time of food; c) amount of starch present; d) diet antinutrients. Under influence of this factors, process of digestion happen by enzymatic activity a long the gastrointestinal tract. Salivary and pancreatic amylase; glycosidases of the duodenal enterocyte brush border (lactase, sacarase and maltase), whose activity happen by close interaction of digestive breakdown with transport. The summarized pathways of the absorptive process: 1. movement from the bulk phase of the lumenal or mucosal fluid to enterocyte surface; 2. movement across the brush border membrane through specific transporters: a) SGLT1; b) GLUT 5; c) passive diffusion. 3. movement across the basolateral membrane by the GLUT 2.

Carbohydrate Analysis

NASA Astrophysics Data System (ADS)

Bemiller, James N.

Carbohydrates are important in foods as a major source of energy, to impart crucial textural properties, and as dietary fiber which influences physiological processes. Digestible carbohydrates, which are converted into monosaccharides, which are absorbed, provide metabolic energy. Worldwide, carbohydrates account for more than 70% of the caloric value of the human diet. It is recommended that all persons should limit calories from fat (the other significant source) to not more than 30% and that most of the carbohydrate calories should come from starch. Nondigestible polysaccharides (all those other than starch) comprise the major portion of dietary fiber (Sect. 10.5). Carbohydrates also contribute other attributes, including bulk, body, viscosity, stability to emulsions and foams, water-holding capacity, freeze-thaw stability, browning, flavors, aromas, and a range of desirable textures (from crispness to smooth, soft gels). They also provide satiety. Basic carbohydrate structures, chemistry, and terminology can be found in references (1, 2).

Chemoselective Reactions for the Synthesis of Glycoconjugates from Unprotected Carbohydrates.

PubMed

Villadsen, Klaus; Martos-Maldonado, Manuel C; Jensen, Knud J; Thygesen, Mikkel B

2017-04-04

Glycobiology is the comprehensive biological investigation of carbohydrates. The study of the role and function of complex carbohydrates often requires the attachment of carbohydrates to surfaces, their tagging with fluorophores, or their conversion into natural or non-natural glycoconjugates, such as glycopeptides or glycolipids. Glycobiology and its "omics", glycomics, require easy and robust chemical methods for the construction of these glycoconjugates. This review gives an overview of the rapidly expanding field of chemical reactions that selectively convert unprotected carbohydrates into glycoconjugates through the anomeric position. The discussion is divided in terms of the anomeric bond type of the newly formed glycoconjugates, including O-, N-, S-, and C-glycosides. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improved AFM Mapping of ICF Target Surfaces

NASA Astrophysics Data System (ADS)

Olson, D. K.; Drake, T.; Frey, D.; Huang, H.; Stephens, R. B.

2003-10-01

Targets for Inertial Confinement Fusion (ICF) research are made from spherical shells with very strict requirements on surface smoothness. Hydrodynamic instabilities are amplified by the presence of surface defects, greatly reducing the gain of ICF targets. Sub-micron variations in the surface can be examined using an Atomic Force Microscope. The current sphere mapping assembly at General Atomics is designed to trace near the equator of a rotating sphere under the AFM head. Spheres are traced on three mutually orthogonal planes. The ˜10 mm piezo-electric actuator range limits how far off the equator we can scan spheres of millimeter diameter. Because only a small fraction of the target's surface can be covered, localized high-mode defects are difficult to detect. In order to meet the needs of ICF research, we need to scan more surface area of the sphere with the AFM. By integrating an additional stepping motor to the sphere mapping assembly, we will be able to recenter the piezo driver of the AFM while mapping. This additional ability allows us to increase the amount of the sphere's surface we are able to scan with the AFM by extending the range of the AFM from the sphere's equator.

Study of surface carbohydrates in Galba truncatula tissues before and after infection with Fasciola hepatica

PubMed Central

Georgieva, Katya; Georgieva, Liliya; Mizinska-Boevska, Yana; Stoitsova, Stoyanka R

2016-01-01

The presence and distribution of surface carbohydrates in the tissues of Galba truncatula snails uninfected or after infection with Fasciola hepatica as well as on the surface of the snail-pathogenic larval stages of the parasite were studied by lectin labelling assay. This is an attempt to find similarities that indicate possible mimicry, utilised by the parasite as an evasion strategy in this snail-trematode system. Different binding patterns were identified on head-foot-mantle, hepatopancreas, genital glands, renopericardial complex of the host as well as of the snail-pathogenic larval stages of F. hepatica. The infection with F. hepatica leads to changes of labelling with Glycine max in the head-mantle cells and Arachis hypogaea in the tubular epithelium of the hepatopancreas. The lectin binding on the other snail tissues is not changed by the development of the larvae. Our data clearly demonstrated the similarity in labelling of G. truncatula tissues and the surface of the snail-pathogenic larval stages of F. hepatica. The role of glycosylation of the contact surfaces of both organisms in relation to the host-parasite interactions is also discussed. PMID:27384082

Study of surface carbohydrates in Galba truncatula tissues before and after infection with Fasciola hepatica.

PubMed

Georgieva, Katya; Georgieva, Liliya; Mizinska-Boevska, Yana; Stoitsova, Stoyanka R

2016-07-04

The presence and distribution of surface carbohydrates in the tissues of Galba truncatula snails uninfected or after infection with Fasciola hepatica as well as on the surface of the snail-pathogenic larval stages of the parasite were studied by lectin labelling assay. This is an attempt to find similarities that indicate possible mimicry, utilised by the parasite as an evasion strategy in this snail-trematode system. Different binding patterns were identified on head-foot-mantle, hepatopancreas, genital glands, renopericardial complex of the host as well as of the snail-pathogenic larval stages of F. hepatica. The infection with F. hepatica leads to changes of labelling with Glycine max in the head-mantle cells and Arachis hypogaea in the tubular epithelium of the hepatopancreas. The lectin binding on the other snail tissues is not changed by the development of the larvae. Our data clearly demonstrated the similarity in labelling of G. truncatula tissues and the surface of the snail-pathogenic larval stages of F. hepatica. The role of glycosylation of the contact surfaces of both organisms in relation to the host-parasite interactions is also discussed.

Development of gastrointestinal surface. VIII. Lectin identification of carbohydrate differences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pang, K.Y.; Bresson, J.L.; Walker, W.A.

Binding of microvillus membranes (MVM) from newborn and adult rats by concanavalin A (Con A), Ulex europaeus (UEA I), Dolichos bifluorus (DBA), and Triticum vulgaris (WGA) was examined to determine the availability of carbohydrate-containing sites for these lectins on the intestinal surface during development. Consistent patterns of differences in the reaction of MVM with these lectins were found. Con A and UEA had much higher reactivities to MVM of adult than newborn rats. /sup 125/I-labeled-UEA gel overlay experiments revealed the abundance of UEA-binding sites in MVM of adult rat in contrast to the two binding sites in MVM of amore » newborn rat. DBA bound only to MVM of the adults, and very few binding sites were found in immature MVM. In contrast to these lectins, WGA binding was much higher in MVM of the newborns and decreased with maturation. Additional experiments on the age dependence of UEA and DBA reactivities revealed that the most striking changes occur in animals from 2 to 2 wk of age. In MVM from 2-wk-old rats, there were only 13.9% and < 0.2% of the adult binding capacities for UEA and DBA, respectively. By the time the animals were 4 wk old, the binding capacity for UEA had attained close to the level of the adults, whereas for DBA it reached 71.3% of the adult value. These results provide definite evidence of changes in the intestinal surface during perinatal development.« less

A photo-cleavable biotin affinity tag for the facile release of a photo-crosslinked carbohydrate-binding protein.

PubMed

Chang, Tsung-Che; Adak, Avijit K; Lin, Ting-Wei; Li, Pei-Jhen; Chen, Yi-Ju; Lai, Chain-Hui; Liang, Chien-Fu; Chen, Yu-Ju; Lin, Chun-Cheng

2016-03-15

The use of photo-crosslinking glycoprobes represents a powerful strategy for the covalent capture of labile protein complexes and allows detailed characterization of carbohydrate-mediated interactions. The selective release of target proteins from solid support is a key step in functional proteomics. We envisaged that light activation can be exploited for releasing labeled protein in a dual photo-affinity probe-based strategy. To investigate this possibility, we designed a trifunctional, galactose-based, multivalent glycoprobe for affinity labeling of carbohydrate-binding proteins. The resulting covalent protein-probe adduct is attached to a photo-cleavable biotin affinity tag; the biotin moiety enables specific presentation of the conjugate on streptavidin-coated beads, and the photolabile linker allows the release of the labeled proteins. This dual probe promotes both the labeling and the facile cleavage of the target protein complexes from the solid surfaces and the remainder of the cell lysate in a completely unaltered form, thus eliminating many of the common pitfalls associated with traditional affinity-based purification methods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging.

PubMed

Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

2016-07-25

Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes.

Systemic localization of seven major types of carbohydrates on cell membranes by dSTORM imaging

PubMed Central

Chen, Junling; Gao, Jing; Zhang, Min; Cai, Mingjun; Xu, Haijiao; Jiang, Junguang; Tian, Zhiyuan; Wang, Hongda

2016-01-01

Carbohydrates on the cell surface control intercellular interactions and play a vital role in various physiological processes. However, their systemic distribution patterns are poorly understood. Through the direct stochastic optical reconstruction microscopy (dSTORM) strategy, we systematically revealed that several types of representative carbohydrates are found in clustered states. Interestingly, the results from dual-color dSTORM imaging indicate that these carbohydrate clusters are prone to connect with one another and eventually form conjoined platforms where different functional glycoproteins aggregate (e.g., epidermal growth factor receptor, (EGFR) and band 3 protein). A thorough understanding of the ensemble distribution of carbohydrates on the cell surface paves the way for elucidating the structure-function relationship of cell membranes and the critical roles of carbohydrates in various physiological and pathological cell processes. PMID:27453176

Carbohydrates.

PubMed

Cocinero, Emilio J; Çarçabal, Pierre

2015-01-01

Although carbohydrates represent one of the most important families of biomolecules, they remain under-studied in comparison to the other biomolecular families (peptides, nucleobases). Beyond their best-known function of energy source in living systems, they act as mediator of molecular recognition processes, carrying molecular information in the so-called "sugar code," just to name one of their countless functions. Owing to their high conformational flexibility, they encode extremely rich information conveyed via the non-covalent hydrogen bonds within the carbohydrate and with other biomolecular assemblies, such as peptide subunits of proteins. Over the last decade there has been tremendous progress in the study of the conformational preferences of neutral oligosaccharides, and of the interactions between carbohydrates and various molecular partners (water, aromatic models, and peptide models), using vibrational spectroscopy as a sensitive probe. In parallel, other spectroscopic techniques have recently become available to the study of carbohydrates in the gas phase (microwave spectroscopy, IRMPD on charged species).

A convenient method for synthesis of glyconanoparticles for colorimetric measuring carbohydrate-protein interactions

PubMed Central

Chuang, Yen-Jun; Zhou, Xichun; Pan, Zhengwei; Turchi, Craig

2009-01-01

Carbohydrate functionalized nanoparticles, i.e., the glyconanoparticles, have wide application ranging from studies of carbohydrate-protein interactions, in vivo cell imaging, biolabeling, etc. Currently reported methods for preparation of glyconanoaprticles require multi-step modifications of carbohydrates moieties to conjugate to nanoparticle surface. However, the required synthetic manipulations are difficult and time consuming. We report herewith a simple and versatile method for preparing glyconanoparticles. This method is based on the utilization of clean and convenient microwave irradiation energy for one-step, site-specific conjugation of unmodified carbohydrates onto hydrazide-functionalized Au nanoparticles. A colorimetric assay that utilizes the ensemble of gold glyconanoparticles and Concanavalin A (ConA) was also presented. This feasible assay system was developed to analyze multivalent interactions and to determine the dissociation constant (Kd) for five kind of Au glyconanoparticles with lectin. Surface plasmon changes of the Au glyconanparticles as a function of lectin-carbohydrate interactions were measured and the dissociation constants were determined based on non-linear curve fitting. The strength of the interaction of carbohydrates with ConA was found to be as follows: Maltose > Mannose > Glucose > Lactose > MAN5. PMID:19698698

Parasite Carbohydrate Vaccines.

PubMed

Jaurigue, Jonnel A; Seeberger, Peter H

2017-01-01

Vaccination is an efficient means of combating infectious disease burden globally. However, routine vaccines for the world's major human parasitic diseases do not yet exist. Vaccines based on carbohydrate antigens are a viable option for parasite vaccine development, given the proven success of carbohydrate vaccines to combat bacterial infections. We will review the key components of carbohydrate vaccines that have remained largely consistent since their inception, and the success of bacterial carbohydrate vaccines. We will then explore the latest developments for both traditional and non-traditional carbohydrate vaccine approaches for three of the world's major protozoan parasitic diseases-malaria, toxoplasmosis, and leishmaniasis. The traditional prophylactic carbohydrate vaccine strategy is being explored for malaria. However, given that parasite disease biology is complex and often arises from host immune responses to parasite antigens, carbohydrate vaccines against deleterious immune responses in host-parasite interactions are also being explored. In particular, the highly abundant glycosylphosphatidylinositol molecules specific for Plasmodium, Toxoplasma , and Leishmania spp. are considered exploitable antigens for this non-traditional vaccine approach. Discussion will revolve around the application of these protozoan carbohydrate antigens for vaccines currently in preclinical development.

Parasite Carbohydrate Vaccines

PubMed Central

Jaurigue, Jonnel A.; Seeberger, Peter H.

2017-01-01

Vaccination is an efficient means of combating infectious disease burden globally. However, routine vaccines for the world's major human parasitic diseases do not yet exist. Vaccines based on carbohydrate antigens are a viable option for parasite vaccine development, given the proven success of carbohydrate vaccines to combat bacterial infections. We will review the key components of carbohydrate vaccines that have remained largely consistent since their inception, and the success of bacterial carbohydrate vaccines. We will then explore the latest developments for both traditional and non-traditional carbohydrate vaccine approaches for three of the world's major protozoan parasitic diseases—malaria, toxoplasmosis, and leishmaniasis. The traditional prophylactic carbohydrate vaccine strategy is being explored for malaria. However, given that parasite disease biology is complex and often arises from host immune responses to parasite antigens, carbohydrate vaccines against deleterious immune responses in host-parasite interactions are also being explored. In particular, the highly abundant glycosylphosphatidylinositol molecules specific for Plasmodium, Toxoplasma, and Leishmania spp. are considered exploitable antigens for this non-traditional vaccine approach. Discussion will revolve around the application of these protozoan carbohydrate antigens for vaccines currently in preclinical development. PMID:28660174

A novel carbohydrate-binding surface layer protein from the hyperthermophilic archaeon Pyrococcus horikoshii.

PubMed

Goda, Shuichiro; Koga, Tomoyuki; Yamashita, Kenichiro; Kuriura, Ryo; Ueda, Toshifumi

2018-04-08

In Archaea and Bacteria, surface layer (S-layer) proteins form the cell envelope and are involved in cell protection. In the present study, a putative S-layer protein was purified from the crude extract of Pyrococcus horikoshii using affinity chromatography. The S-layer gene was cloned and expressed in Escherichia coli. Isothermal titration calorimetry analyses showed that the S-layer protein bound N-acetylglucosamine and induced agglutination of the gram-positive bacterium Micrococcus lysodeikticus. The protein comprised a 21-mer structure, with a molecular mass of 1,340 kDa, as determined using small-angle X-ray scattering. This protein showed high thermal stability, with a midpoint of thermal denaturation of 79 °C in dynamic light scattering experiments. This is the first description of the carbohydrate-binding archaeal S-layer protein and its characteristics.

Quantitative assessment of the multivalent protein-carbohydrate interactions on silicon.

PubMed

Yang, Jie; Chazalviel, Jean-Noël; Siriwardena, Aloysius; Boukherroub, Rabah; Ozanam, François; Szunerits, Sabine; Gouget-Laemmel, Anne Chantal

2014-10-21

A key challenge in the development of glycan arrays is that the sensing interface be fabricated reliably so as to ensure the sensitive and accurate analysis of the protein-carbohydrate interaction of interest, reproducibly. These goals are complicated in the case of glycan arrays as surface sugar density can influence dramatically the strength and mode of interaction of the sugar ligand at any interface with lectin partners. In this Article, we describe the preparation of carboxydecyl-terminated crystalline silicon (111) surfaces onto which are grafted either mannosyl moieties or a mixture of mannose and spacer alcohol molecules to provide "diluted" surfaces. The fabrication of the silicon surfaces was achieved efficiently through a strategy implicating a "click" coupling step. The interactions of these newly fabricated glycan interfaces with the lectin, Lens culinaris, have been characterized using quantitative infrared (IR) spectroscopy in the attenuated total geometry (ATR). The density of mannose probes and lectin targets was precisely determined for the first time by the aid of special IR calibration experiments, thus allowing for the interpretation of the distribution of mannose and its multivalent binding with lectins. These experimental findings were accounted for by numerical simulations of lectin adsorption.

Binding Preferences, Surface Attachment, Diffusivity, and Orientation of a Family 1 Carbohydrate-binding Module on Cellulose*

PubMed Central

Nimlos, Mark R.; Beckham, Gregg T.; Matthews, James F.; Bu, Lintao; Himmel, Michael E.; Crowley, Michael F.

2012-01-01

Cellulase enzymes often contain carbohydrate-binding modules (CBMs) for binding to cellulose. The mechanisms by which CBMs recognize specific surfaces of cellulose and aid in deconstruction are essential to understand cellulase action. The Family 1 CBM from the Trichoderma reesei Family 7 cellobiohydrolase, Cel7A, is known to selectively bind to hydrophobic surfaces of native cellulose. It is most commonly suggested that three aromatic residues identify the planar binding face of this CBM, but several recent studies have challenged this hypothesis. Here, we use molecular simulation to study the CBM binding orientation and affinity on hydrophilic and hydrophobic cellulose surfaces. Roughly 43 μs of molecular dynamics simulations were conducted, which enables statistically significant observations. We quantify the fractions of the CBMs that detach from crystal surfaces or diffuse to other surfaces, the diffusivity along the hydrophobic surface, and the overall orientation of the CBM on both hydrophobic and hydrophilic faces. The simulations demonstrate that there is a thermodynamic driving force for the Cel7A CBM to bind preferentially to the hydrophobic surface of cellulose relative to hydrophilic surfaces. In addition, the simulations demonstrate that the CBM can diffuse from hydrophilic surfaces to the hydrophobic surface, whereas the reverse transition is not observed. Lastly, our simulations suggest that the flat faces of Family 1 CBMs are the preferred binding surfaces. These results enhance our understanding of how Family 1 CBMs interact with and recognize specific cellulose surfaces and provide insights into the initial events of cellulase adsorption and diffusion on cellulose. PMID:22496371

Potential targets for next generation antimicrobial glycoconjugate vaccines

PubMed Central

Micoli, Francesca; Costantino, Paolo; Adamo, Roberto

2018-01-01

Abstract Cell surface carbohydrates have been proven optimal targets for vaccine development. Conjugation of polysaccharides to a carrier protein triggers a T-cell-dependent immune response to the glycan moiety. Licensed glycoconjugate vaccines are produced by chemical conjugation of capsular polysaccharides to prevent meningitis caused by meningococcus, pneumococcus and Haemophilus influenzae type b. However, other classes of carbohydrates (O-antigens, exopolysaccharides, wall/teichoic acids) represent attractive targets for developing vaccines. Recent analysis from WHO/CHO underpins alarming concern toward antibiotic-resistant bacteria, such as the so called ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) and additional pathogens such as Clostridium difficile and Group A Streptococcus. Fungal infections are also becoming increasingly invasive for immunocompromised patients or hospitalized individuals. Other emergencies could derive from bacteria which spread during environmental calamities (Vibrio cholerae) or with potential as bioterrorism weapons (Burkholderia pseudomallei and mallei, Francisella tularensis). Vaccination could aid reducing the use of broad-spectrum antibiotics and provide protection by herd immunity also to individuals who are not vaccinated. This review analyzes structural and functional differences of the polysaccharides exposed on the surface of emerging pathogenic bacteria, combined with medical need and technological feasibility of corresponding glycoconjugate vaccines. PMID:29547971

Carbohydrates as allergens.

PubMed

Commins, Scott P

2015-01-01

Complex carbohydrates are effective inducers of Th2 responses, and carbohydrate antigens can stimulate the production of glycan-specific antibodies. In instances where the antigen exposure occurs through the skin, the resulting antibody production can contain IgE class antibody. The glycan-stimulated IgE may be non-specific but may also be antigen specific. This review focuses on the production of cross-reactive carbohydrate determinants, the recently identified IgE antibody response to a mammalian oligosaccharide epitope, galactose-alpha-1,3-galactose (alpha-gal), as well as discusses practical implications of carbohydrates in allergy. In addition, the biological effects of carbohydrate antigens are reviewed in setting of receptors and host recognition.

Carbohydrates in Supramolecular Chemistry.

PubMed

Delbianco, Martina; Bharate, Priya; Varela-Aramburu, Silvia; Seeberger, Peter H

2016-02-24

Carbohydrates are involved in a variety of biological processes. The ability of sugars to form a large number of hydrogen bonds has made them important components for supramolecular chemistry. We discuss recent advances in the use of carbohydrates in supramolecular chemistry and reveal that carbohydrates are useful building blocks for the stabilization of complex architectures. Systems are presented according to the scaffold that supports the glyco-conjugate: organic macrocycles, dendrimers, nanomaterials, and polymers are considered. Glyco-conjugates can form host-guest complexes, and can self-assemble by using carbohydrate-carbohydrate interactions and other weak interactions such as π-π interactions. Finally, complex supramolecular architectures based on carbohydrate-protein interactions are discussed.

Distributions and seasonal variations of dissolved carbohydrates in the Jiaozhou Bay, China

NASA Astrophysics Data System (ADS)

Yang, Gui-Peng; Zhang, Yan-Ping; Lu, Xiao-Lan; Ding, Hai-Bing

2010-06-01

Surface seawater samples were collected in the Jiaozhou Bay, a typical semi-closed basin located at the western part of the Shandong Peninsula, China, during four cruises. Concentrations of monosaccharides (MCHO), polysaccharides (PCHO) and total dissolved carbohydrates (TCHO) were measured with the 2,4,6-tripyridyl- s-triazine spectroscopic method. Concentrations of TCHO varied from 10.8 to 276.1 μM C for all samples and the ratios of TCHO to dissolved organic carbon (DOC) ranged from 1.1 to 67.9% with an average of 10.1%. This result indicated that dissolved carbohydrates were an important constituent of DOC in the surface seawater of the Jiaozhou Bay. In all samples, the concentrations of MCHO ranged from 2.9 to 65.9 μM C, comprising 46.1 ± 16.6% of TCHO on average, while PCHO ranged from 0.3 to 210.2 μM C, comprising 53.9 ± 16.6% of TCHO on average. As a major part of dissolved carbohydrates, the concentrations of PCHO were higher than those of MCHO. MCHO and PCHO accumulated in January and July, with minimum average concentration in April. The seasonal variation in the ratios of TCHO to DOC was related to water temperature, with high values in January and low values in July and October. The concentrations of dissolved carbohydrates displayed a decreasing trend from the coastal to the central areas. Negative correlations between concentrations of TCHO and salinity in July suggested that riverine input around the Jiaozhou Bay had an important effect on the concentrations of dissolved carbohydrates in surface seawater. The pattern of distributions of MCHO and PCHO reported in this study added to the global picture of dissolved carbohydrates distribution.

Attachment of Salmonella strains to a plant cell wall model is modulated by surface characteristics and not by specific carbohydrate interactions.

PubMed

Tan, Michelle Sze-Fan; Moore, Sean C; Tabor, Rico F; Fegan, Narelle; Rahman, Sadequr; Dykes, Gary A

2016-09-15

Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface. We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin. Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by

Carbohydrate terminology and classification.

PubMed

Cummings, J H; Stephen, A M

2007-12-01

Dietary carbohydrates are a group of chemically defined substances with a range of physical and physiological properties and health benefits. As with other macronutrients, the primary classification of dietary carbohydrate is based on chemistry, that is character of individual monomers, degree of polymerization (DP) and type of linkage (alpha or beta), as agreed at the Food and Agriculture Organization/World Health Organization Expert Consultation in 1997. This divides carbohydrates into three main groups, sugars (DP 1-2), oligosaccharides (short-chain carbohydrates) (DP 3-9) and polysaccharides (DP> or =10). Within this classification, a number of terms are used such as mono- and disaccharides, polyols, oligosaccharides, starch, modified starch, non-starch polysaccharides, total carbohydrate, sugars, etc. While effects of carbohydrates are ultimately related to their primary chemistry, they are modified by their physical properties. These include water solubility, hydration, gel formation, crystalline state, association with other molecules such as protein, lipid and divalent cations and aggregation into complex structures in cell walls and other specialized plant tissues. A classification based on chemistry is essential for a system of measurement, predication of properties and estimation of intakes, but does not allow a simple translation into nutritional effects since each class of carbohydrate has overlapping physiological properties and effects on health. This dichotomy has led to the use of a number of terms to describe carbohydrate in foods, for example intrinsic and extrinsic sugars, prebiotic, resistant starch, dietary fibre, available and unavailable carbohydrate, complex carbohydrate, glycaemic and whole grain. This paper reviews these terms and suggests that some are more useful than others. A clearer understanding of what is meant by any particular word used to describe carbohydrate is essential to progress in translating the growing knowledge of the

Different allocation of carbohydrates and phenolics in dehydrated leaves of triticale.

PubMed

Hura, Tomasz; Dziurka, Michał; Hura, Katarzyna; Ostrowska, Agnieszka; Dziurka, Kinga

2016-09-01

Carbohydrates are used in plant growth processes, osmotic regulation and secondary metabolism. A study of the allocation of carbohydrates to a target set of metabolites during triticale acclimation to soil drought was performed. The study included a semi-dwarf cultivar 'Woltario' and a long-stemmed cultivar 'Moderato', differing in the activity of the photosynthetic apparatus under optimum growth conditions. Differences were found in the quantitative and qualitative composition of individual carbohydrates and phenolic compounds, depending on the developmental stage and water availability. Soluble carbohydrates in the semi-dwarf 'Woltario' cv. under soil drought were utilized for synthesis of starch, soluble phenolic compounds and an accumulation of cell wall carbohydrates. In the typical 'Moderato' cv., soluble carbohydrates were primarily used for the synthesis of phenolic compounds that were then incorporated into cell wall structures. Increased content of cell wall-bound phenolics in 'Moderato' cv. improved the cell wall tightness and reduced the rate of leaf water loss. In 'Woltario' cv., the increase in cell osmotic potential due to an enhanced concentration of carbohydrates and proline was insufficient to slow down the rate of leaf water loss. The mechanism of cell wall tightening in response to leaf desiccation may be the main key in the process of triticale acclimation to soil drought. Copyright © 2016 Elsevier GmbH. All rights reserved.

Radiolabeled Peptide Scaffolds for PET/SPECT - Optical in Vivo Imaging of Carbohydrate-Lectin Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deutscher, Susan

2014-09-30

The objective of this research is to develop phage display-selected peptides into radio- and fluoresecently- labeled scaffolds for the multimodal imaging of carbohydrate-lectin interactions. While numerous protein and receptor systems are being explored for the development of targeted imaging agents, the targeting and analysis of carbohydrate-lectin complexes in vivo remains relatively unexplored. Antibodies, nanoparticles, and peptides are being developed that target carbohydrate-lectin complexes in living systems. However, antibodies and nanoparticles often suffer from slow clearance and toxicity problems. Peptides are attractive alternative vehicles for the specific delivery of radionuclides or fluorophores to sites of interest in vivo, although, because ofmore » their size, uptake and retention may be less than antibodies. We have selected high affinity peptides that bind a specific carbohydrate-lectin complex involved in cell-cell adhesion and cross-linking using bacteriophage (phage) display technologies (1,2). These peptides have allowed us to probe the role of these antigens in cell adhesion. Fluorescent versions of the peptides have been developed for optical imaging and radiolabeled versions have been used in single photon emission computed tomography (SPECT) and positron emission tomography (PET) in vivo imaging (3-6). A benefit in employing the radiolabeled peptides in SPECT and PET is that these imaging modalities are widely used in living systems and offer deep tissue sensitivity. Radiolabeled peptides, however, often exhibit poor stability and high kidney uptake in vivo. Conversely, optical imaging is sensitive and offers good spatial resolution, but is not useful for deep tissue penetration and is semi-quantitative. Thus, multimodality imaging that relies on the strengths of both radio- and optical- imaging is a current focus for development of new in vivo imaging agents. We propose a novel means to improve the efficacy of radiolabeled and

Carbohydrate-Aromatic Interactions in Proteins.

PubMed

Hudson, Kieran L; Bartlett, Gail J; Diehl, Roger C; Agirre, Jon; Gallagher, Timothy; Kiessling, Laura L; Woolfson, Derek N

2015-12-09

Protein-carbohydrate interactions play pivotal roles in health and disease. However, defining and manipulating these interactions has been hindered by an incomplete understanding of the underlying fundamental forces. To elucidate common and discriminating features in carbohydrate recognition, we have analyzed quantitatively X-ray crystal structures of proteins with noncovalently bound carbohydrates. Within the carbohydrate-binding pockets, aliphatic hydrophobic residues are disfavored, whereas aromatic side chains are enriched. The greatest preference is for tryptophan with an increased prevalence of 9-fold. Variations in the spatial orientation of amino acids around different monosaccharides indicate specific carbohydrate C-H bonds interact preferentially with aromatic residues. These preferences are consistent with the electronic properties of both the carbohydrate C-H bonds and the aromatic residues. Those carbohydrates that present patches of electropositive saccharide C-H bonds engage more often in CH-π interactions involving electron-rich aromatic partners. These electronic effects are also manifested when carbohydrate-aromatic interactions are monitored in solution: NMR analysis indicates that indole favorably binds to electron-poor C-H bonds of model carbohydrates, and a clear linear free energy relationships with substituted indoles supports the importance of complementary electronic effects in driving protein-carbohydrate interactions. Together, our data indicate that electrostatic and electronic complementarity between carbohydrates and aromatic residues play key roles in driving protein-carbohydrate complexation. Moreover, these weak noncovalent interactions influence which saccharide residues bind to proteins, and how they are positioned within carbohydrate-binding sites.

Energy and carbohydrate for training and recovery.

PubMed

Burke, Louise M; Loucks, Anne B; Broad, Nick

2006-07-01

Soccer players should achieve an energy intake that provides sufficient carbohydrate to fuel the training and competition programme, supplies all nutrient requirements, and allows manipulation of energy or nutrient balance to achieve changes in lean body mass, body fat or growth. Although the traditional culture of soccer has focused on carbohydrate intake for immediate match preparation, top players should adapt their carbohydrate intake on a daily basis to ensure adequate fuel for training and recovery between matches. For players with a mobile playing style, there is sound evidence that dietary programmes that restore and even super-compensate muscle glycogen levels can enhance activity patterns during matches. This will presumably also benefit intensive training, such as twice daily practices. As well as achieving a total intake of carbohydrate commensurate with fuel needs, the everyday diet should promote strategic intake of carbohydrate and protein before and after key training sessions to optimize the adaptations and enhance recovery. The achievement of the ideal physique for soccer is a long-term goal that should be undertaken over successive years, and particularly during the off-season and pre-season. An increase in lean body mass or a decrease in body fat is the product of a targeted training and eating programme. Consultation with a sports nutrition expert can assist soccer players to manipulate energy and nutrient intake to meet such goals. Players should be warned against the accidental or deliberate mismatch of energy intake and energy expenditure, such that energy availability (intake minus the cost of exercise) falls below 125 kJ (30 kcal) per kilogram of fat-free mass per day. Such low energy availability causes disturbances to hormonal, metabolic, and immune function.

Separation of carbohydrates using hydrophilic interaction liquid chromatography.

PubMed

Fu, Qing; Liang, Tu; Li, Zhenyu; Xu, Xiaoyong; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

2013-09-20

A strategy was developed to rapidly evaluate chromatographic properties of hydrophilic interaction chromatography (HILIC) columns for separating carbohydrates. Seven HILIC columns (Silica, Diol, TSK Amide-80, XAmide, Click Maltose, Click β-CD, and Click TE-Cys columns) were evaluated by using three monosaccharide and seven disaccharides as probes. The influence of column temperature on the peak shape and tautomerization of carbohydrates, as well as column selectivity were investigated. The influence of surface charge property on the retention was also studied by using glucose, glucuronic acid, and glucosamine, which indicated that buffer salt concentration and pH value in mobile phase was necessary to control the ionic interactions between ionic carbohydrates and HILIC columns. According to evaluation results, the XAmide column was selected as an example to establish experimental schemes for separation of complex mixtures of oligosaccharide. Copyright © 2013 Elsevier Ltd. All rights reserved.

Flow cytometric analysis of lectin binding to in vitro-cultured Perkinsus marinus surface carbohydrates

USGS Publications Warehouse

Gauthier, J.D.; Jenkins, J.A.; La Peyre, Jerome F.

2004-01-01

Parasite surface glycoconjugates are frequently involved in cellular recognition and colonization of the host. This study reports on the identification of Perkinsus marinus surface carbohydrates by flow cytometric analyses of fluorescein isothiocyanate-conjugated lectin binding. Lectin-binding specificity was confirmed by sugar inhibition and Kolmogorov-Smirnov statistics. Clear, measurable fluorescence peaks were discriminated, and no parasite autofluorescence was observed. Parasites (GTLA-5 and Perkinsus-1 strains) harvested during log and stationary phases of growth in a protein-free medium reacted strongly with concanavalin A and wheat germ agglutinin, which bind to glucose-mannose and N-acetyl-D-glucosamine (GlcNAc) moieties, respectively. Both P. marinus strains bound with lower intensity to Maclura pomifera agglutinin, Bauhinia purpurea agglutinin, soybean agglutinin (N-acetyl-D-galactosamine-specific lectins), peanut agglutinin (PNA) (terminal galactose specific), and Griffonia simplicifolia II (GlcNAc specific). Only background fluorescence levels were detected with Ulex europaeus agglutinin I (L-fucose specific) and Limulus polyphemus agglutinin (sialic acid specific). The lectin-binding profiles were similar for the 2 strains except for a greater relative binding intensity of PNA for Perkinsus-1 and an overall greater lectin-binding capacity of Perkinsus-1 compared with GTLA-5. Growth stage comparisons revealed increased lectin-binding intensities during stationary phase compared with log phase of growth. This is the first report of the identification of surface glycoconjugates on a Perkinsus spp. by flow cytometry and the first to demonstrate that differential surface sugar expression is growth phase and strain dependent. ?? American Society of Parasitologists 2004.

Characterization of the carbohydrate components of Taenia solium oncosphere proteins and their role in the antigenicity.

PubMed

Arana, Yanina; Verastegui, Manuela; Tuero, Iskra; Grandjean, Louis; Garcia, Hector H; Gilman, Robert H

2013-10-01

This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that posttranslational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells.

CHARACTERIZATION OF THE CARBOHYDRATE COMPONENTS OF Taenia solium ONCOSPHERE PROTEINS AND THEIR ROLE IN THE ANTIGENICITY

PubMed Central

Arana, Yanina; Verastegui, Manuela; Tuero, Iskra; Grandjean, Louis; Garcia, Hector H.; Gilman, Robert H.

2015-01-01

This study examines the carbohydrate composition of Taenia solium whole oncosphere antigens (WOAs), in order to improve the understanding of the antigenicity of the T. solium. Better knowledge of oncosphere antigens is crucial to accurately diagnose previous exposure to T. solium eggs and thus predict the development of neurocysticercosis. A set of seven lectins conjugates with wide carbohydrate specificity were used on parasite fixations and somatic extracts. Lectin fluorescence revealed that D-mannose, D-glucose, D-galactose and N-acetyl-D-galactosamine residues were the most abundant constituents of carbohydrate chains on the surface of T. solium oncosphere. Lectin blotting showed that post-translational modification with N-glycosylation was abundant while little evidence of O-linked carbohydrates was observed. Chemical oxidation and enzymatic deglycosylation in situ were performed to investigate the immunoreactivity of the carbohydrate moieties. Linearizing or removing the carbohydrate moieties from the protein backbones did not diminish the immunoreactivity of these antigens, suggesting that a substantial part of the host immune response against T. solium oncosphere is directed against the peptide epitopes on the parasite antigens. Finally, using carbohydrate probes, we demonstrated for the first time that the presence of several lectins on the surface of the oncosphere was specific to carbohydrates found in intestinal mucus, suggesting a possible role in initial attachment of the parasite to host cells. PMID:23982308

High carbohydrate-low protein consumption maximizes Drosophila lifespan

PubMed Central

Bruce, Kimberley D.; Hoxha, Sany; Carvalho, Gil B.; Yamada, Ryuichi; Wang, Horng-Dar; Karayan, Paul; He, Shan; Brummel, Ted; Kapahi, Pankaj; Ja, William W.

2013-01-01

Dietary restriction extends lifespan in a variety of organisms, but the key nutritional components driving this process and how they interact remain uncertain. In Drosophila, while a substantial body of research suggests that protein is the major dietary component affecting longevity, recent studies claim that carbohydrates also play a central role. To clarify how nutritional factors influence longevity, nutrient consumption and lifespan were measured on a series of diets with varying yeast and sugar content. We show that optimal lifespan requires both high carbohydrate and low protein consumption, but neither nutrient by itself entirely predicts lifespan. Increased dietary carbohydrate or protein concentration does not always result in reduced feeding—the regulation of food consumption is best described by a constant daily caloric intake target. Moreover, due to differences in food intake, increased concentration of a nutrient within the diet does not necessarily result in increased consumption of that particular nutrient. Our results shed light on the issue of dietary effects on lifespan and highlight the need for accurate measures of nutrient intake in dietary manipulation studies. PMID:23403040

Dietary intakes, attitudes toward carbohydrates of postmenopausal women following low carbohydrate diets.

PubMed

Winham, Donna M; Collins, Courtney B; Hutchins, Andrea M

2009-01-01

Middle-aged women have the highest levels of obesity and comprise the largest group of dieters. Few investigators have examined how women apply weight-loss diet principles in an unsupervised setting. Dietary intakes and attitudes toward carbohydrates were examined in women who were self-reported low carbohydrate dieters (SRLCDs); these intakes and attitudes were compared with those of women who were following their normal diet (non-dieters [NDs]). A convenience sample of 29 postmenopausal women aged 45 to 65 was recruited. Data were obtained by interview, questionnaire, and direct anthropometric measurement. Descriptive statistics, chi-square analysis, and analysis of variance were used to compare groups. Although total energy and protein intakes were similar, SRLCDs consumed significantly more fat and less carbohydrate (expressed as a percentage of total energy) and more cholesterol and less fibre than did NDs. Both groups had unfavourable attitudes toward carbohydrates. The SRLCDs ate more fat than recommended. Women who are considering following a low carbohydrate diet need to know the nutritional risks of unbalanced self-designed low carbohydrate diets. Negative attitudes toward carbohydrates were not confined to dieters. Nutrition education is necessary to help consumers understand basic nutrition principles and to be more skeptical of fad diets.

Streptococcus oralis Neuraminidase Modulates Adherence to Multiple Carbohydrates on Platelets.

PubMed

Singh, Anirudh K; Woodiga, Shireen A; Grau, Margaret A; King, Samantha J

2017-03-01

Adherence to host surfaces is often mediated by bacterial binding to surface carbohydrates. Although it is widely appreciated that some bacterial species express glycosidases, previous studies have not considered whether bacteria bind to multiple carbohydrates within host glycans as they are modified by bacterial glycosidases. Streptococcus oralis is a leading cause of subacute infective endocarditis. Binding to platelets is a critical step in disease; however, the mechanisms utilized by S. oralis remain largely undefined. Studies revealed that S. oralis , like Streptococcus gordonii and Streptococcus sanguinis , binds platelets via terminal sialic acid. However, unlike those organisms, S. oralis produces a neuraminidase, NanA, which cleaves terminal sialic acid. Further studies revealed that following NanA-dependent removal of terminal sialic acid, S. oralis bound exposed β-1,4-linked galactose. Adherence to both these carbohydrates required Fap1, the S. oralis member of the serine-rich repeat protein (SRRP) family of adhesins. Mutation of a conserved residue required for sialic acid binding by other SRRPs significantly reduced platelet binding, supporting the hypothesis that Fap1 binds this carbohydrate. The mechanism by which Fap1 contributes to β-1,4-linked galactose binding remains to be defined; however, binding may occur via additional domains of unknown function within the nonrepeat region, one of which shares some similarity with a carbohydrate binding module. This study is the first demonstration that an SRRP is required to bind β-1,4-linked galactose and the first time that one of these adhesins has been shown to be required for binding of multiple glycan receptors. Copyright © 2017 American Society for Microbiology.

Digestion and Absorption of Carbohydrates

USDA-ARS?s Scientific Manuscript database

Carbohydrates are the major dietary sources of energy for humans. While most dietary carbohydrates are derived from multiple botanical sources, lactose and trehalose are the only animal-derived carbohydrates. Digestion of starch, the carbohydrate most abundantly consumed by humans, depends on the c...

Carbohydrate Nanoparticles for Brain Delivery.

PubMed

Lalatsa, A; Barbu, E

2016-01-01

Many brain tumors and neurological diseases can greatly benefit from the use of emerging nanotechnologies based on targeted nanomedicines that are able to noninvasively transport highly potent and specific pharmaceuticals across the blood-brain barrier. Carbohydrates have received considerable interest as materials for drug carriers due to their natural origin and inherent biodegradability and biocompatibility, as well as due to their hydrophilic character and ease of chemical modification combined with low cost and the possibility for large-scale manufacturing. This chapter provides an overview of the latest research involving the use of carbohydrate-based nanoparticles for drug delivery to the central nervous system. After reviewing the challenges posed by delivering drugs into the brain, the current state-of-the-art approaches for delivery of actives across the blood-brain barrier, including invasive and noninvasive strategies, are presented. A particular focus has been placed on chitosan polymers as they are among the most promising carbohydrate nanocarriers for the preparation and testing of chitosan-based nanomedicines that led, in preclinical proof-of-concept studies, to enhanced brain drug levels and increased pharmacodynamics responses after intravenous, nasal, and oral administration. While chitosan nanoparticles are to date among the most studied and most promising carriers, approaches based on other polysaccharides such as dextran, pullulan, and cellulose warrant further research in the attempt to advance the existing technologies for overcoming the blood-brain barrier. © 2016 Elsevier Inc. All rights reserved.

A monoclonal antibody recognizes undifferentiation-specific carbohydrate moieties expressed on cell surface of the human dental pulp cells.

PubMed

Kang, Kyung-Jung; Ko, Seon-Yle; Ryu, Chun-Jeih; Jang, Young-Joo

2017-05-01

Human dental pulp cells are obtained from dental pulp tissue, and have the ability to form dentin and a pulp-like complex. Although adult stem cells have been identified from the primary culture by using specific cell surface markers, the identity of surface markers for the purification of stem cells within the dental pulp population are still unclear. Previously, we had constructed monoclonal antibodies against the undifferentiated cell-specific surface markers of human dental pulp cells (hDPCs) by performing decoy immunization. Among them, a monoclonal antibody against the cell surface antigen of the undifferentiated hDPCs (named UPSA-1) was purified and its heavy and light chain consensus regions were analyzed. The cell surface binding affinity of UPSA-1 mAb on the undifferentiated hDPCs was stronger than that on the differentiated cells. When tunicamycin was applied to hDPSCs during culture, the cell surface binding affinity of the antibody was dramatically decreased, and dentinogenic differentiation was reduced. The purified UPSA-1 antigen band resulting from immunoprecipitation disappeared or shifted down on the SDS-PAGE by deglycosylation. These data suggested that glycosylation on the cell surface might be a marker of an undifferentiated state, and that UPSA-1 mAb might be useful for identifying the carbohydrate moiety on the cell surface of undifferentiated pulp cells. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Lectin-Binding Specificity of the Fertilization-Relevant Protein PDC-109 by Means of Surface Plasmon Resonance and Carbohydrate REcognition Domain EXcision-Mass Spectrometry.

PubMed

Defaus, Sira; Avilés, Manuel; Andreu, David; Gutiérrez-Gallego, Ricardo

2018-04-04

Seminal plasma proteins are relevant for sperm functionality and some appear responsible for establishing sperm interactions with the various environments along the female genital tract towards the oocyte. In recent years, research has focused on characterizing the role of these proteins in the context of reproductive biology, fertility diagnostics and treatment of related problems. Herein, we focus on the main protein of bovine seminal plasma, PDC-109 (BSP-A1/-A2), which by virtue of its lectin properties is involved in fertilization. By means of surface plasmon resonance, the interaction of PDC-109 with a panel of the most relevant glycosidic epitopes of mammals has been qualitatively and quantitatively characterized, and a higher affinity for carbohydrates containing fucose has been observed, in line with previous studies. Additionally, using the orthogonal technique of Carbohydrate REcognition Domain EXcision-Mass Spectrometry (CREDEX-MS), the recognition domain of the interaction complexes between PDC-109 and all fucosylated disaccharides [(Fuc-α1,(3,4,6)-GlcNAc)] has been defined, revealing the specific glycotope and the peptide domain likely to act as the PDC-109 carbohydrate binding site.

Carbohydrates in diversity-oriented synthesis: challenges and opportunities.

PubMed

Lenci, E; Menchi, G; Trabocchi, A

2016-01-21

Over the last decade, Diversity-Oriented Synthesis (DOS) has become a new paradigm for developing large collections of structurally diverse small molecules as probes to investigate biological pathways, and to provide a larger array of the chemical space. Drug discovery and chemical biology are taking advantage of DOS approaches to exploit highly-diverse and complex molecular platforms, producing advances in both target and ligand discovery. In this view, carbohydrates are attractive building blocks for DOS libraries, due to their stereochemical diversity and high density of polar functional groups, thus offering many possibilities for chemical manipulation and scaffold decoration. This review will discuss research contributions and perspectives on the application of carbohydrate chemistry to explore the accessible chemical space through appendage, stereochemical and scaffold diversity.

Target surface finding using 3D SAR data

NASA Astrophysics Data System (ADS)

Ruiter, Jason R.; Burns, Joseph W.; Subotic, Nikola S.

2005-05-01

Methods of generating more literal, easily interpretable imagery from 3-D SAR data are being studied to provide all weather, near-visual target identification and/or scene interpretation. One method of approaching this problem is to automatically generate shape-based geometric renderings from the SAR data. In this paper we describe the application of the Marching Tetrahedrons surface finding algorithm to 3-D SAR data. The Marching Tetrahedrons algorithm finds a surface through the 3-D data cube, which provides a recognizable representation of the target surface. This algorithm was applied to the public-release X-patch simulations of a backhoe, which provided densely sampled 3-D SAR data sets. The performance of the algorithm to noise and spatial resolution were explored. Surface renderings were readily recognizable over a range of spatial resolution, and maintained their fidelity even under relatively low Signal-to-Noise Ratio (SNR) conditions.

Target Trailing With Safe Navigation for Maritime Autonomous Surface Vehicles

NASA Technical Reports Server (NTRS)

Wolf, Michael; Kuwata, Yoshiaki; Zarzhitsky, Dimitri V.

2013-01-01

This software implements a motion-planning module for a maritime autonomous surface vehicle (ASV). The module trails a given target while also avoiding static and dynamic surface hazards. When surface hazards are other moving boats, the motion planner must apply International Regulations for Avoiding Collisions at Sea (COLREGS). A key subset of these rules has been implemented in the software. In case contact with the target is lost, the software can receive and follow a "reacquisition route," provided by a complementary system, until the target is reacquired. The programmatic intention is that the trailed target is a submarine, although any mobile naval platform could serve as the target. The algorithmic approach to combining motion with a (possibly moving) goal location, while avoiding local hazards, may be applicable to robotic rovers, automated landing systems, and autonomous airships. The software operates in JPL s CARACaS (Control Architecture for Robotic Agent Command and Sensing) software architecture and relies on other modules for environmental perception data and information on the predicted detectability of the target, as well as the low-level interface to the boat controls.

Molecular simulations of carbohydrates and protein-carbohydrate interactions: motivation, issues and prospects.

PubMed

Fadda, Elisa; Woods, Robert J

2010-08-01

The characterization of the 3D structure of oligosaccharides, their conjugates and analogs is particularly challenging for traditional experimental methods. Molecular simulation methods provide a basis for interpreting sparse experimental data and for independently predicting conformational and dynamic properties of glycans. Here, we summarize and analyze the issues associated with modeling carbohydrates, with a detailed discussion of four of the most recently developed carbohydrate force fields, reviewed in terms of applicability to natural glycans, carbohydrate-protein complexes and the emerging area of glycomimetic drugs. In addition, we discuss prospectives and new applications of carbohydrate modeling in drug discovery.

A Carbohydrate Moiety of Secreted Stage-Specific Glycoprotein 4 Participates in Host Cell Invasion by Trypanosoma cruzi Extracellular Amastigotes.

PubMed

Florentino, Pilar T V; Real, Fernando; Orikaza, Cristina M; da Cunha, Julia P C; Vitorino, Francisca N L; Cordero, Esteban M; Sobreira, Tiago J P; Mortara, Renato A

2018-01-01

Trypanosoma cruzi is the etiologic agent of Chagas' disease. It is known that amastigotes derived from trypomastigotes in the extracellular milieu are infective in vitro and in vivo . Extracellular amastigotes (EAs) have a stage-specific surface antigen called Ssp-4, a GPI-anchored glycoprotein that is secreted by the parasites. By immunoprecipitation with the Ssp-4-specific monoclonal antibodies (mAb) 2C2 and 1D9, we isolated the glycoprotein from EAs. By mass spectrometry, we identified the core protein of Ssp-4 and evaluated mRNA expression and the presence of Ssp-4 carbohydrate epitopes recognized by mAb1D9. We demonstrated that the carbohydrate epitope recognized by mAb1D9 could promote host cell invasion by EAs. Although infectious EAs express lower amounts of Ssp-4 compared with less-infectious EAs (at the mRNA and protein levels), it is the glycosylation of Ssp-4 (identified by mAb1D9 staining only in infectious strains and recognized by galectin-3 on host cells) that is the determinant of EA invasion of host cells. Furthermore, Ssp-4 is secreted by EAs, either free or associated with parasite vesicles, and can participate in host-cell interactions. The results presented here describe the possible role of a carbohydrate moiety of T. cruzi surface glycoproteins in host cell invasion by EA forms, highlighting the potential of these moieties as therapeutic and vaccine targets for the treatment of Chagas' disease.

A Carbohydrate Moiety of Secreted Stage-Specific Glycoprotein 4 Participates in Host Cell Invasion by Trypanosoma cruzi Extracellular Amastigotes

PubMed Central

Florentino, Pilar T. V.; Real, Fernando; Orikaza, Cristina M.; da Cunha, Julia P. C.; Vitorino, Francisca N. L.; Cordero, Esteban M.; Sobreira, Tiago J. P.; Mortara, Renato A.

2018-01-01

Trypanosoma cruzi is the etiologic agent of Chagas’ disease. It is known that amastigotes derived from trypomastigotes in the extracellular milieu are infective in vitro and in vivo. Extracellular amastigotes (EAs) have a stage-specific surface antigen called Ssp-4, a GPI-anchored glycoprotein that is secreted by the parasites. By immunoprecipitation with the Ssp-4-specific monoclonal antibodies (mAb) 2C2 and 1D9, we isolated the glycoprotein from EAs. By mass spectrometry, we identified the core protein of Ssp-4 and evaluated mRNA expression and the presence of Ssp-4 carbohydrate epitopes recognized by mAb1D9. We demonstrated that the carbohydrate epitope recognized by mAb1D9 could promote host cell invasion by EAs. Although infectious EAs express lower amounts of Ssp-4 compared with less-infectious EAs (at the mRNA and protein levels), it is the glycosylation of Ssp-4 (identified by mAb1D9 staining only in infectious strains and recognized by galectin-3 on host cells) that is the determinant of EA invasion of host cells. Furthermore, Ssp-4 is secreted by EAs, either free or associated with parasite vesicles, and can participate in host-cell interactions. The results presented here describe the possible role of a carbohydrate moiety of T. cruzi surface glycoproteins in host cell invasion by EA forms, highlighting the potential of these moieties as therapeutic and vaccine targets for the treatment of Chagas’ disease. PMID:29692765

Carbohydrate Loading.

ERIC Educational Resources Information Center

Csernus, Marilyn

Carbohydrate loading is a frequently used technique to improve performance by altering an athlete's diet. The objective is to increase glycogen stored in muscles for use in prolonged strenuous exercise. For two to three days, the athlete consumes a diet that is low in carbohydrates and high in fat and protein while continuing to exercise and…

Using Carbohydrate Interaction Assays to Reveal Novel Binding Sites in Carbohydrate Active Enzymes.

PubMed

Cockburn, Darrell; Wilkens, Casper; Dilokpimol, Adiphol; Nakai, Hiroyuki; Lewińska, Anna; Abou Hachem, Maher; Svensson, Birte

2016-01-01

Carbohydrate active enzymes often contain auxiliary binding sites located either on independent domains termed carbohydrate binding modules (CBMs) or as so-called surface binding sites (SBSs) on the catalytic module at a certain distance from the active site. The SBSs are usually critical for the activity of their cognate enzyme, though they are not readily detected in the sequence of a protein, but normally require a crystal structure of a complex for their identification. A variety of methods, including affinity electrophoresis (AE), insoluble polysaccharide pulldown (IPP) and surface plasmon resonance (SPR) have been used to study auxiliary binding sites. These techniques are complementary as AE allows monitoring of binding to soluble polysaccharides, IPP to insoluble polysaccharides and SPR to oligosaccharides. Here we show that these methods are useful not only for analyzing known binding sites, but also for identifying new ones, even without structural data available. We further verify the chosen assays discriminate between known SBS/CBM containing enzymes and negative controls. Altogether 35 enzymes are screened for the presence of SBSs or CBMs and several novel binding sites are identified, including the first SBS ever reported in a cellulase. This work demonstrates that combinations of these methods can be used as a part of routine enzyme characterization to identify new binding sites and advance the study of SBSs and CBMs, allowing them to be detected in the absence of structural data.

Using Carbohydrate Interaction Assays to Reveal Novel Binding Sites in Carbohydrate Active Enzymes

PubMed Central

Wilkens, Casper; Dilokpimol, Adiphol; Nakai, Hiroyuki; Lewińska, Anna; Abou Hachem, Maher; Svensson, Birte

2016-01-01

Carbohydrate active enzymes often contain auxiliary binding sites located either on independent domains termed carbohydrate binding modules (CBMs) or as so-called surface binding sites (SBSs) on the catalytic module at a certain distance from the active site. The SBSs are usually critical for the activity of their cognate enzyme, though they are not readily detected in the sequence of a protein, but normally require a crystal structure of a complex for their identification. A variety of methods, including affinity electrophoresis (AE), insoluble polysaccharide pulldown (IPP) and surface plasmon resonance (SPR) have been used to study auxiliary binding sites. These techniques are complementary as AE allows monitoring of binding to soluble polysaccharides, IPP to insoluble polysaccharides and SPR to oligosaccharides. Here we show that these methods are useful not only for analyzing known binding sites, but also for identifying new ones, even without structural data available. We further verify the chosen assays discriminate between known SBS/CBM containing enzymes and negative controls. Altogether 35 enzymes are screened for the presence of SBSs or CBMs and several novel binding sites are identified, including the first SBS ever reported in a cellulase. This work demonstrates that combinations of these methods can be used as a part of routine enzyme characterization to identify new binding sites and advance the study of SBSs and CBMs, allowing them to be detected in the absence of structural data. PMID:27504624

Recognition of xyloglucan by the crystalline cellulose-binding site of a family 3a carbohydrate-binding module

PubMed Central

Hernandez-Gomez, Mercedes C.; Rydahl, Maja G.; Rogowski, Artur; Morland, Carl; Cartmell, Alan; Crouch, Lucy; Labourel, Aurore; Fontes, Carlos M. G. A.; Willats, William G. T.; Gilbert, Harry J; Knox, J. Paul

2018-01-01

Type A non-catalytic carbohydrate-binding modules (CBMs), exemplified by CtCBM3acipA, are widely believed to specifically target crystalline cellulose through entropic forces. Here we have tested the hypothesis that type A CBMs can also bind to xyloglucan, a soluble β-1,4-glucan containing α-1,6-xylose side chains. CtCBM3acipA bound to xyloglucan in cell walls and arrayed on solid surfaces. Xyloglucan and cellulose were shown to bind to the same planar surface on CBM3acipA. A range of type A CBMs from different families were shown to bind to xyloglucan in solution with ligand binding driven by enthalpic changes. The nature of CBM-polysaccharide interactions is discussed. PMID:26193423

Molecular Tools for Facilitative Carbohydrate Transporters (Gluts).

PubMed

Tanasova, Marina; Fedie, Joseph R

2017-09-19

Facilitative carbohydrate transporters-Gluts-have received wide attention over decades due to their essential role in nutrient uptake and links with various metabolic disorders, including diabetes, obesity, and cancer. Endeavors directed towards understanding the mechanisms of Glut-mediated nutrient uptake have resulted in a multidisciplinary research field spanning protein chemistry, chemical biology, organic synthesis, crystallography, and biomolecular modeling. Gluts became attractive targets for cancer research and medicinal chemistry, leading to the development of new approaches to cancer diagnostics and providing avenues for cancer-targeting therapeutics. In this review, the current state of knowledge of the molecular interactions behind Glut-mediated sugar uptake, Glut-targeting probes, therapeutics, and inhibitors are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sugar-binding sites on the surface of the carbohydrate-binding module of CBH I from Trichoderma reesei.

PubMed

Tavagnacco, Letizia; Mason, Philip E; Schnupf, Udo; Pitici, Felicia; Zhong, Linghao; Himmel, Michael E; Crowley, Michael; Cesàro, Attilio; Brady, John W

2011-05-01

Molecular dynamics simulations were carried out for a system consisting of the carbohydrate-binding module (CBM) of the cellulase CBH I from Trichoderma reesei (Hypocrea jecorina) in a concentrated solution of β-D-glucopyranose, to determine whether there is any tendency for the sugar molecules to bind to the CBM. In spite of the general tendency of glucose to behave as an osmolyte, a marked tendency for the sugar molecules to bind to the protein was observed. However, the glucose molecules tended to bind only to specific sites on the protein. As expected, the hydrophobic face of the sugar molecules, comprising the axial H1, H3, and H5 aliphatic protons, tended to adhere to the flat faces of the three tyrosine side chains on the planar binding surface of the CBM. However, a significant tendency to bind to a groove-like feature on the upper surface of the CBM was also observed. These results would not be inconsistent with a model of the mechanism for this globular domain in which the cellodextrin chain being removed from the surface of crystalline cellulose passes over the upper surface of the CBM, presumably then available for hydrolysis in the active site tunnel of this processive cellulase. Copyright © 2011 Elsevier Ltd. All rights reserved.

Synthesis of Carbohydrate Capped Silicon Nanoparticles and their Reduced Cytotoxicity, In Vivo Toxicity, and Cellular Uptake.

PubMed

Ahire, Jayshree H; Behray, Mehrnaz; Webster, Carl A; Wang, Qi; Sherwood, Victoria; Saengkrit, Nattika; Ruktanonchai, Uracha; Woramongkolchai, Noppawan; Chao, Yimin

2015-08-26

The development of smart targeted nanoparticles (NPs) that can identify and deliver drugs at a sustained rate directly to cancer cells may provide better efficacy and lower toxicity for treating primary and advanced metastatic tumors. Obtaining knowledge of the diseases at the molecular level can facilitate the identification of biological targets. In particular, carbohydrate-mediated molecular recognitions using nano-vehicles are likely to increasingly affect cancer treatment methods, opening a new area in biomedical applications. Here, silicon NPs (SiNPs) capped with carbohydrates including galactose, glucose, mannose, and lactose are successfully synthesized from amine terminated SiNPs. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] analysis shows an extensive reduction in toxicity of SiNPs by functionalizing with carbohydrate moiety both in vitro and in vivo. Cellular uptake is investigated with flow cytometry and confocal fluorescence microscope. The results show the carbohydrate capped SiNPs can be internalized in the cells within 24 h of incubation, and can be taken up more readily by cancer cells than noncancerous cells. Moreover, these results reinforce the use of carbohydrates for the internalization of a variety of similar compounds into cancer cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Learning about Carbohydrates

MedlinePlus

... added sugar and doesn't contain important nutrients. Complex carbohydrates: These are also called starches. Starches include grain ... pasta, and rice. As with simple sugars, some complex carbohydrate foods are better choices than others. Refined (say: ...

Carbohydrates and Diabetes

MedlinePlus

... Staying Safe Videos for Educators Search English Español Carbohydrates and Diabetes KidsHealth / For Teens / Carbohydrates and Diabetes ... Los carbohidratos y la diabetes Carbs and Blood Sugar Keeping your blood sugar levels on track means ...

Impact of Dietary Carbohydrate and Protein Levels on Carbohydrate Metabolism

ERIC Educational Resources Information Center

Lasker, Denise Ann

2009-01-01

The goal of this dissertation was to investigate the impact of changing dietary carbohydrate (CARB) intakes within recommended dietary guidelines on metabolic outcomes specifically associated with glycemic regulations and carbohydrate metabolism. This research utilized both human and animal studies to examine changes in metabolism across a wide…

Lanthanide-IMAC enrichment of carbohydrates and polyols.

PubMed

Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

2014-03-01

In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions. Copyright © 2013 John Wiley & Sons, Ltd.

Surface-modified gold nanorods for specific cell targeting

NASA Astrophysics Data System (ADS)

Wang, Chan-Ung; Arai, Yoshie; Kim, Insun; Jang, Wonhee; Lee, Seonghyun; Hafner, Jason H.; Jeoung, Eunhee; Jung, Deokho; Kwon, Youngeun

2012-05-01

Gold nanoparticles (GNPs) have unique properties that make them highly attractive materials for developing functional reagents for various biomedical applications including photothermal therapy, targeted drug delivery, and molecular imaging. For in vivo applications, GNPs need to be prepared with very little or negligible cytotoxicitiy. Most GNPs are, however, prepared using growth-directing surfactants such as cetyl trimethylammonium bromide (CTAB), which are known to have considerable cytotoxicity. In this paper, we describe an approach to remove CTAB to a non-toxic concentration. We optimized the conditions for surface modification with methoxypolyethylene glycol thiol (mPEG), which replaced CTAB and formed a protective layer on the surface of gold nanorods (GNRs). The cytotoxicities of pristine and surface-modified GNRs were measured in primary human umbilical vein endothelial cells and human cell lines derived from hepatic carcinoma cells, embryonic kidney cells, and thyroid papillary carcinoma cells. Cytotoxicity assays revealed that treating cells with GNRs did not significantly affect cell viability except for thyroid papillary carcinoma cells. Thyroid cancer cells were more susceptible to residual CTAB, so CTAB had to be further removed by dialysis in order to use GNRs for thyroid cell targeting. PEGylated GNRs are further modified to present monoclonal antibodies that recognize a specific surface marker, Na-I symporter, for thyroid cells. Antibody-conjugated GNRs specifically targeted human thyroid cells in vitro.

The carbohydrate sequence markup language (CabosML): an XML description of carbohydrate structures.

PubMed

Kikuchi, Norihiro; Kameyama, Akihiko; Nakaya, Shuuichi; Ito, Hiromi; Sato, Takashi; Shikanai, Toshihide; Takahashi, Yoriko; Narimatsu, Hisashi

2005-04-15

Bioinformatics resources for glycomics are very poor as compared with those for genomics and proteomics. The complexity of carbohydrate sequences makes it difficult to define a common language to represent them, and the development of bioinformatics tools for glycomics has not progressed. In this study, we developed a carbohydrate sequence markup language (CabosML), an XML description of carbohydrate structures. The language definition (XML Schema) and an experimental database of carbohydrate structures using an XML database management system are available at http://www.phoenix.hydra.mki.co.jp/CabosDemo.html kikuchi@hydra.mki.co.jp.

Synthesis of carbohydrate-based surfactants

DOEpatents

Pemberton, Jeanne E.; Polt, Robin L.; Maier, Raina M.

2016-11-22

The present invention provides carbohydrate-based surfactants and methods for producing the same. Methods for producing carbohydrate-based surfactants include using a glycosylation promoter to link a carbohydrate or its derivative to a hydrophobic compound.

Modeling and validation of spectral BRDF on material surface of space target

NASA Astrophysics Data System (ADS)

Hou, Qingyu; Zhi, Xiyang; Zhang, Huili; Zhang, Wei

2014-11-01

The modeling and the validation methods of the spectral BRDF on the material surface of space target were presented. First, the microscopic characteristics of the space targets' material surface were analyzed based on fiber-optic spectrometer using to measure the direction reflectivity of the typical materials surface. To determine the material surface of space target is isotropic, atomic force microscopy was used to measure the material surface structure of space target and obtain Gaussian distribution model of microscopic surface element height. Then, the spectral BRDF model based on that the characteristics of the material surface were isotropic and the surface micro-facet with the Gaussian distribution which we obtained was constructed. The model characterizes smooth and rough surface well for describing the material surface of the space target appropriately. Finally, a spectral BRDF measurement platform in a laboratory was set up, which contains tungsten halogen lamp lighting system, fiber optic spectrometer detection system and measuring mechanical systems with controlling the entire experimental measurement and collecting measurement data by computers automatically. Yellow thermal control material and solar cell were measured with the spectral BRDF, which showed the relationship between the reflection angle and BRDF values at three wavelengths in 380nm, 550nm, 780nm, and the difference between theoretical model values and the measured data was evaluated by relative RMS error. Data analysis shows that the relative RMS error is less than 6%, which verified the correctness of the spectral BRDF model.

Carbohydrates and Diabetes (For Parents)

MedlinePlus

... Staying Safe Videos for Educators Search English Español Carbohydrates and Diabetes KidsHealth / For Parents / Carbohydrates and Diabetes ... many kids with diabetes take to stay healthy. Carbohydrates and Blood Sugar The two main forms of ...

Carbohydrate-protein interactions investigated on plastic chips statically coated with hydrophobically modified hydroxyethylcellulose.

PubMed

Dang, Fuquan; Maeda, Eiki; Osafune, Tomo; Nakajima, Kazuki; Kakehi, Kazuaki; Ishikawa, Mitsuru; Baba, Yoshinobu

2009-12-15

We developed a novel method for rapid screening of carbohydrate-protein interactions using poly(methyl methacrylate) (PMMA) channels statically coated with hydrophobically modified hydroxyethylcellulose (HM-HEC). We found that a self-assembled monolayer (SAM) of HM-HEC on a PMMA surface intact by water allows rapid and reproducible separations of glycan samples using a 20 mM phosphate without HM-HEC. The underlying mechanism for dynamic and static coatings on the PMMA surface is discussed. Simultaneous analysis of the molecular interaction between a complex mixture of carbohydrates from alpha1-acid glycoprotein and proteins has been successfully achieved in PMMA channels statically coated with a SAM of HM-HEC.

Exponential increase in postprandial blood-glucose exposure with increasing carbohydrate loads using a linear carbohydrate-to-insulin ratio.

PubMed

Marran, K J; Davey, B; Lang, A; Segal, D G

2013-04-10

Postprandial glucose excursions contribute significantly to average blood glucose, glycaemic variability and cardiovascular risk. Carbohydrate counting is a method of insulin dosing that balances carbohydrate load to insulin dose using a fixed ratio. Many patients and current insulin pumps calculate insulin delivery for meals based on a linear carbohydrate-to-insulin relationship. It is our hypothesis that a non-linear relationship exists between the amounts of carbohydrate consumed and the insulin required to cover it. To document blood glucose exposure in response to increasing carbohydrate loads on fixed carbohydrate-to-insulin ratios. Five type 1 diabetic subjects receiving insulin pump therapy with good control were recruited. Morning basal rates and carbohydrate- to-insulin ratios were optimised. A Medtronic glucose sensor was used for 5 days to collect data for area-under-the-curve (AUC) analysis, during which standardised meals of increasing carbohydrate loads were consumed. Increasing carbohydrate loads using a fixed carbohydrate-to-insulin ratio resulted in increasing glucose AUC. The relationship was found to be exponential rather than linear. Late postprandial hypoglycaemia followed carbohydrate loads of >60 g and this was often followed by rebound hyperglycaemia that lasted >6 hours. A non-linear relationship exists between carbohydrates consumed and the insulin required to cover them. This has implications for control of postprandial blood sugars, especially when consuming large carbohydrate loads. Further studies are required to look at the optimal ratios, duration and type of insulin boluses required to cover increasing carbohydrate loads.

[Performance enhancement by carbohydrate intake during sport: effects of carbohydrates during and after high-intensity exercise].

PubMed

Beelen, Milou; Cermak, Naomi M; van Loon, Luc J C

2015-01-01

Endogenous carbohydrate availability does not provide sufficient energy for prolonged moderate to high-intensity exercise. Carbohydrate ingestion during high-intensity exercise can therefore enhance performance.- For exercise lasting 1 to 2.5 hours, athletes are advised to ingest 30-60 g of carbohydrates per hour.- Well-trained endurance athletes competing for longer than 2.5 hours at high intensity can metabolise up to 90 g of carbohydrates per hour, provided that a mixture of glucose and fructose is ingested.- Athletes participating in intermittent or team sports are advised to follow the same strategies but the timing of carbohydrate intake depends on the type of sport.- If top performance is required again within 24 hours after strenuous exercise, the advice is to supplement endogenous carbohydrate supplies quickly within the first few hours post-exercise by ingesting large amounts of carbohydrate (1.2 g/kg/h) or a lower amount of carbohydrate (0.8 g/kg/h) with a small amount of protein (0.2-0.4 g/kg/h).

Unique carbohydrate binding platforms employed by the glucan phosphatases

PubMed Central

MEEKINS, David A.; GENTRY, Matthew S.

2016-01-01

Glucan phosphatases are a family of enzymes that are functionally conserved at the enzymatic level in animals and plants. These enzymes bind and dephosphorylate glycogen in animals and starch in plants. While the enzymatic function is conserved, the glucan phosphatases employ distinct mechanisms to bind and dephosphorylate glycogen or starch. The founding member of the family is a bimodular human protein called laforin that is comprised of a carbohydrate binding module 20 (CBM20) followed by a dual specificity phosphatase domain. Plants contain two glucan phosphatases: Starch EXcess4 (SEX4) and Like Sex Four2 (LSF2). SEX4 contains a chloroplast targeting peptide, dual specificity phosphatase (DSP) domain, a CBM45, and a carboxy-terminal motif. LSF2 is comprised of simply a chloroplast targeting peptide, DSP domain, and carboxy-terminal motif. SEX4 employs an integrated DSP-CBM glucan-binding platform to engage and dephosphorylate starch. LSF2 lacks a CBM and instead utilizes two surface binding sites to bind and dephosphorylate starch. Laforin is a dimeric protein in solution and it utilizes a tetramodular architecture and cooperativity to bind and dephosphorylate glycogen. This chapter describes the biological role of glucan phosphatases in glycogen and starch metabolism and compares and contrasts their ability to bind and dephosphorylate glucans. PMID:27147465

Quantitative NMR Approach to Optimize the Formation of Chemical Building Blocks from Abundant Carbohydrates.

PubMed

Elliot, Samuel G; Tolborg, Søren; Sádaba, Irantzu; Taarning, Esben; Meier, Sebastian

2017-07-21

The future role of biomass-derived chemicals relies on the formation of diverse functional monomers in high yields from carbohydrates. Recently, it has become clear that a series of α-hydroxy acids, esters, and lactones can be formed from carbohydrates in alcohol and water solvents using tin-containing catalysts such as Sn-Beta. These compounds are potential building blocks for polyesters bearing additional olefin and alcohol functionalities. An NMR approach was used to identify, quantify, and optimize the formation of these building blocks in the Sn-Beta-catalyzed transformation of abundant carbohydrates. Record yields of the target molecules can be achieved by obstructing competing reactions through solvent selection. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radioiodinated branched carbohydrates

DOEpatents

Goodman, Mark M.; Knapp, Jr., Furn F.

1989-01-01

A radioiodinated branched carbohydrate for tissue imaging. Iodine-123 is stabilized in the compound by attaching it to a vinyl functional group that is on the carbohydrate. The compound exhibits good uptake and retention and is promising in the development of radiopharmaceuticals for brain, heart and tumor imaging.

Cats and Carbohydrates: The Carnivore Fantasy?

PubMed Central

Verbrugghe, Adronie; Hesta, Myriam

2017-01-01

The domestic cat’s wild ancestors are obligate carnivores that consume prey containing only minimal amounts of carbohydrates. Evolutionary events adapted the cat’s metabolism and physiology to this diet strictly composed of animal tissues and led to unique digestive and metabolic peculiarities of carbohydrate metabolism. The domestic cat still closely resembles its wild ancestor. Although the carnivore connection of domestic cats is well recognised, little is known about the precise nutrient profile to which the digestive physiology and metabolism of the cat have adapted throughout evolution. Moreover, studies show that domestic cats balance macronutrient intake by selecting low-carbohydrate foods. The fact that cats evolved consuming low-carbohydrate prey has led to speculations that high-carbohydrate diets could be detrimental for a cat’s health. More specifically, it has been suggested that excess carbohydrates could lead to feline obesity and diabetes mellitus. Additionally, the chances for remission of diabetes mellitus are higher in cats that consume a low-carbohydrate diet. This literature review will summarise current carbohydrate knowledge pertaining to digestion, absorption and metabolism of carbohydrates, food selection and macronutrient balancing in healthy, obese and diabetic cats, as well as the role of carbohydrates in prevention and treatment of obesity and diabetes mellitus. PMID:29140289

Carbohydrate Cluster Microarrays Fabricated on 3-Dimensional Dendrimeric Platforms for Functional Glycomics Exploration

PubMed Central

Zhou, Xichun; Turchi, Craig; Wang, Denong

2009-01-01

We reported here a novel, ready-to-use bioarray platform and methodology for construction of sensitive carbohydrate cluster microarrays. This technology utilizes a 3-dimensional (3-D) poly(amidoamine) starburst dendrimer monolayer assembled on glass surface, which is functionalized with terminal aminooxy and hydrazide groups for site-specific coupling of carbohydrates. A wide range of saccharides, including monosaccharides, oligosaccharides and polysaccharides of diverse structures, are applicable for the 3-D bioarray platform without prior chemical derivatization. The process of carbohydrate coupling is effectively accelerated by microwave radiation energy. The carbohydrate concentration required for microarray fabrication is substantially reduced using this technology. Importantly, this bioarray platform presents sugar chains in defined orientation and cluster configurations. It is, thus, uniquely useful for exploration of the structural and conformational diversities of glyco-epitope and their functional properties. PMID:19791771

Glycan Reader: Automated Sugar Identification and Simulation Preparation for Carbohydrates and Glycoproteins

PubMed Central

Jo, Sunhwan; Song, Kevin C.; Desaire, Heather; MacKerell, Alexander D.; Im, Wonpil

2011-01-01

Understanding how glycosylation affects protein structure, dynamics, and function is an emerging and challenging problem in biology. As a first step toward glycan modeling in the context of structural glycobiology, we have developed Glycan Reader and integrated it into the CHARMM-GUI, http://www.charmm-gui.org/input/glycan. Glycan Reader greatly simplifies the reading of PDB structure files containing glycans through (i) detection of carbohydrate molecules, (ii) automatic annotation of carbohydrates based on their three-dimensional structures, (iii) recognition of glycosidic linkages between carbohydrates as well as N-/O-glycosidic linkages to proteins, and (iv) generation of inputs for the biomolecular simulation program CHARMM with the proper glycosidic linkage setup. In addition, Glycan Reader is linked to other functional modules in CHARMM-GUI, allowing users to easily generate carbohydrate or glycoprotein molecular simulation systems in solution or membrane environments and visualize the electrostatic potential on glycoprotein surfaces. These tools are useful for studying the impact of glycosylation on protein structure and dynamics. PMID:21815173

Behavioural responses of the snail Lymnaea acuminata to carbohydrates in snail-attractant pellets

NASA Astrophysics Data System (ADS)

Tiwari, Farindra; Singh, D. K.

Snail control is one of the most important tools in the campaign to reduce the incidence of fascioliasis. In order to attain this objective, the method of bait formulation in order to contain an attractant and a molluscicide is an expedient approach to lure the target snail population to the molluscicide. This study identifies certain carbohydrates, namely sucrose, maltose, glucose, fructose and starch, for preparing such baits. These were tested on Lymnaea acuminata, an intermediate host of the digenean trematodes Fasciola hepatica and Fasciola gigantica. The behavioural responses of snails to these carbohydrates were examined. Significant variations in behavioural responses were observed in the snail even when the five carbohydrates were used in low concentrations in snail-attractant pellets. Starch emerged as the strongest attractant for Lymnaea acuminata, followed by maltose.

Benefits and hazards of dietary carbohydrate.

PubMed

Connor, William E; Duell, P Barton; Connor, Sonja L

2005-11-01

Since the dawn of civilization, carbohydrate has comprised the largest source of energy in the diet for most populations. The source of the carbohydrate has been from plants in the form of complex carbohydrate high in fiber. Only in affluent cultures has sugar contributed so much of the total energy. When carbohydrate is consumed as a major component of a plant-based diet, a high-carbohydrate, low-fat diet is associated with low plasma levels of total and low-density lipoprotein cholesterol, less coronary heart disease, less diabetes, and less obesity. Very low-carbohydrate (ketogenic) diets may provide short-term solutions but do not lead to a long-term solution for most people.

Renewable Hydrogen Carrier - Carbohydrate: Constructing the Carbon-Neutral Carbohydrate Economy

DTIC Science & Technology

2011-01-31

temperature. High fructose corn syrup , low-cost sucrose replacement, is made by stabilized glucose isomerase, which can work at ~60 °C for even about two...sustainable production, high -density storage, costly infrastructure, to eliminating safety concern. The use of renewable carbohydrate as a high -density...100% selectivity of enzymes, modest reaction conditions, and high -purity of generated hydrogen, carbohydrate is a promising hydrogen carrier for end

CH/π Interactions in Carbohydrate Recognition.

PubMed

Spiwok, Vojtěch

2017-06-23

Many carbohydrate-binding proteins contain aromatic amino acid residues in their binding sites. These residues interact with carbohydrates in a stacking geometry via CH/π interactions. These interactions can be found in carbohydrate-binding proteins, including lectins, enzymes and carbohydrate transporters. Besides this, many non-protein aromatic molecules (natural as well as artificial) can bind saccharides using these interactions. Recent computational and experimental studies have shown that carbohydrate-aromatic CH/π interactions are dispersion interactions, tuned by electrostatics and partially stabilized by a hydrophobic effect in solvated systems.

Expanded potential of seleno-carbohydrates as a molecular tool for X-ray structural determination of a carbohydrate-protein complex with single/multi-wavelength anomalous dispersion phasing.

PubMed

Suzuki, Tatsuya; Makyio, Hisayoshi; Ando, Hiromune; Komura, Naoko; Menjo, Masanori; Yamada, Yusuke; Imamura, Akihiro; Ishida, Hideharu; Wakatsuki, Soichi; Kato, Ryuichi; Kiso, Makoto

2014-04-01

Seleno-lactoses have been successfully synthesized as candidates for mimicking carbohydrate ligands for human galectin-9 N-terminal carbohydrate recognition domain (NCRD). Selenium was introduced into the mono- or di-saccharides using p-methylselenobenzoic anhydride (Tol2Se) as a novel selenating reagent. The TolSe-substituted monosaccharides were converted into selenoglycosyl donors or acceptors, which were reacted with coupling partners to afford seleno-lactoses. The seleno-lactoses were converted to the target compounds. The structure of human galectin-9 NCRD co-crystallized with 6-MeSe-lactose was determined with single/multi-wavelength anomalous dispersion (SAD/MAD) phasing and was similar to that of the co-crystal with natural lactose. Copyright © 2014 Elsevier Ltd. All rights reserved.

Target surface area effects on hot electron dynamics from high intensity laser–plasma interactions

DOE PAGES

Zulick, C.; Raymond, A.; McKelvey, A.; ...

2016-06-15

Reduced surface area targets were studied using an ultra-high intensity femtosecond laser in order to determine the effect of electron sheath field confinement on electron dynamics. X-ray emission due to energetic electrons was imaged using a K α imaging crystal. Electrons were observed to travel along the surface of wire targets, and were slowed mainly by the induced fields. Targets with reduced surface areas were correlated with increased hot electron densities and proton energies. Furthermore, Hybrid Vlasov–Fokker–Planck simulations demonstrated increased electric sheath field strength in reduced surface area targets.

Molecular simulations of carbohydrates and protein-carbohydrate interactions: motivation, issues and prospects

PubMed Central

Fadda, Elisa; Woods, Robert J.

2014-01-01

The characterization of the 3D structure of oligosaccharides, their conjugates and analogs is particularly challenging for traditional experimental methods. Molecular simulation methods provide a basis for interpreting sparse experimental data and for independently predicting conformational and dynamic properties of glycans. Here, we summarize and analyze the issues associated with modeling carbohydrates, with a detailed discussion of four of the most recently developed carbohydrate force fields, reviewed in terms of applicability to natural glycans, carbohydrate–protein complexes and the emerging area of glycomimetic drugs. In addition, we discuss prospectives and new applications of carbohydrate modeling in drug discovery. PMID:20594934

Isolation of carbohydrate-metabolizing, extremely halophilic bacteria.

NASA Technical Reports Server (NTRS)

Tomlinson, G. A.; Hochstein, L. I.

1972-01-01

Four previously unrecognized strains of extremely halophilic bacteria that utilize carbohydrates have been isolated. Gas production proved an unreliable index of carbohydrate metabolism; therefore, carbohydrate utilization was measured by determining acid formation and sugar disappearance during growth. By these procedures, carbohydrate utilization was readily detected. The results suggest that carbohydrate dissimilation by extremely halophilic bacteria may be more common than previously thought and that the apparent rarity of carbohydrate-metabolizing halophiles may be an artifact of the isolation procedures used.

Sialic acid-triggered macroscopic properties switching on a smart polymer surface

NASA Astrophysics Data System (ADS)

Xiong, Yuting; Li, Minmin; Wang, Hongxi; Qing, Guangyan; Sun, Taolei

2018-01-01

Constructing smart surfaces with responsive polymers capable of dynamically and reversibly changing their chemical and physical properties by responding to the recognition of biomolecules remains a challenging task. And, the key to achieving this purpose relies on the design of polymers to precisely interact with the target molecule and successfully transform the interaction signal into tunable macroscopic properties, further achieve special bio-functions. Herein, inspired by carbohydrate-carbohydrate interaction (CCI) in life system, we developed a three-component copolymer poly(NIPAAm-co-PT-co-Glc) bearing a binding unit glucose (Glc) capable of recognizing sialic acid, a type of important molecular targets for cancer diagnosis and therapy, and reported the sialic acid triggered macroscopic properties switching on this smart polymer surface. Detailed mechanism studies indicated that multiple hydrogen bonding interactions between Glc unit and Neu5Ac destroyed the initial hydrogen bond network of the copolymer, leading to a reversible "contraction-to-swelling" conformational transition of the copolymer chains, accompanied with distinct macroscopic property switching (i.e., surface wettability, morphology, stiffness) of the copolymer film. And these features enabled this copolymer to selectively capture sialic acid-containing glycopeptides from complex protein samples. This work provides an inspiration for the design of novel smart polymeric materials with sensitive responsiveness to sialic acid, which would promote the development of sialic acid-specific bio-devices and drug delivery systems.

Modification of surface oxide layers of titanium targets for increasing lifetime of neutron tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zakharov, A. M., E-mail: zam@plasma.mephi.ru; Dvoichenkova, O. A.; Evsin, A. E.

The peculiarities of interaction of hydrogen ions with a titanium target and its surface oxide layer were studied. Two ways of modification of the surface oxide layers of titanium targets for increasing the lifetime of neutron tubes were proposed: (1) deposition of an yttrium oxide barrier layer on the target surface; (2) implementation of neutron tube work regime in which the target is irradiated with ions with energies lower than 1000 eV between high-energy ion irradiation pulses.

Effects of sugar functional groups, hydrophobicity, and fluorination on carbohydrate-DNA stacking interactions in water.

PubMed

Lucas, Ricardo; Peñalver, Pablo; Gómez-Pinto, Irene; Vengut-Climent, Empar; Mtashobya, Lewis; Cousin, Jonathan; Maldonado, Olivia S; Perez, Violaine; Reynes, Virginie; Aviñó, Anna; Eritja, Ramón; González, Carlos; Linclau, Bruno; Morales, Juan C

2014-03-21

Carbohydrate-aromatic interactions are highly relevant for many biological processes. Nevertheless, experimental data in aqueous solution relating structure and energetics for sugar-arene stacking interactions are very scarce. Here, we evaluate how structural variations in a monosaccharide including carboxyl, N-acetyl, fluorine, and methyl groups affect stacking interactions with aromatic DNA bases. We find small differences on stacking interaction among the natural carbohydrates examined. The presence of fluorine atoms within the pyranose ring slightly increases the interaction with the C-G DNA base pair. Carbohydrate hydrophobicity is the most determinant factor. However, gradual increase in hydrophobicity of the carbohydrate does not translate directly into a steady growth in stacking interaction. The energetics correlates better with the amount of apolar surface buried upon sugar stacking on top of the aromatic DNA base pair.

Carbohydrate Strategies for Injury Prevention

PubMed Central

Schlabach, Gretchen

1994-01-01

Prevention of injury involves identifying risk factors that would predispose one to injury and developing strategies to attenuate or eliminate their presence. Because muscle glycogen depletion is associated with fatigue and injury, it should be treated as a possible risk factor. Muscle glycogen stores are derived almost entirely from carbohydrate intake. Because there is a limited capacity to store muscle glycogen, and because muscle glycogen is the predominant fuel in exercise of moderate to severe intensity, the nutritional focus should be on carbohydrate consumption. Easy-to-follow nutritional strategies should be employed that will maximize muscle glycogen stores and delay the onset of fatigue. Individuals involved in activities lasting less than 60 minutes need to consume an adequate amount of carbohydrate daily and a pre-event meal before the start of the activity. However, individuals participating in activities longer than 60 minutes or participating in activities requiring repeated bouts of high intensity exercise need to: 1) consume an adequate amount of carbohydrate daily, 2) practice carbohydrate loading, 3) consume the pre-event meal, and 4) ingest carbohydrates immediately before, during, and after the activity. PMID:16558287

Autonomous target recognition using remotely sensed surface vibration measurements

NASA Astrophysics Data System (ADS)

Geurts, James; Ruck, Dennis W.; Rogers, Steven K.; Oxley, Mark E.; Barr, Dallas N.

1993-09-01

The remotely measured surface vibration signatures of tactical military ground vehicles are investigated for use in target classification and identification friend or foe (IFF) systems. The use of remote surface vibration sensing by a laser radar reduces the effects of partial occlusion, concealment, and camouflage experienced by automatic target recognition systems using traditional imagery in a tactical battlefield environment. Linear Predictive Coding (LPC) efficiently represents the vibration signatures and nearest neighbor classifiers exploit the LPC feature set using a variety of distortion metrics. Nearest neighbor classifiers achieve an 88 percent classification rate in an eight class problem, representing a classification performance increase of thirty percent from previous efforts. A novel confidence figure of merit is implemented to attain a 100 percent classification rate with less than 60 percent rejection. The high classification rates are achieved on a target set which would pose significant problems to traditional image-based recognition systems. The targets are presented to the sensor in a variety of aspects and engine speeds at a range of 1 kilometer. The classification rates achieved demonstrate the benefits of using remote vibration measurement in a ground IFF system. The signature modeling and classification system can also be used to identify rotary and fixed-wing targets.

Levorotatory carbohydrates and xylitol subdue Streptococcus mutans and Candida albicans adhesion and biofilm formation.

PubMed

Brambilla, Eugenio; Ionescu, Andrei C; Cazzaniga, Gloria; Ottobelli, Marco; Samaranayake, Lakshman P

2016-05-01

Dietary carbohydrates and polyols affect the microbial colonization of oral surfaces by modulating adhesion and biofilm formation. The aim of this study was to evaluate the influence of a select group of l-carbohydrates and polyols on either Streptococcus mutans or Candida albicans adhesion and biofilm formation in vitro. S. mutans or C. albicans suspensions were inoculated on polystyrene substrata in the presence of Tryptic soy broth containing 5% of the following compounds: d-glucose, d-mannose, l-glucose, l-mannose, d- and l-glucose (raceme), d- and l-mannose (raceme), l-glucose and l-mannose, sorbitol, mannitol, and xylitol. Microbial adhesion (2 h) and biofilm formation (24 h) were evaluated using MTT-test and Scanning Electron Microscopy (SEM). Xylitol and l-carbohydrates induced the lowest adhesion and biofilm formation in both the tested species, while sorbitol and mannitol did not promote C. albicans biofilm formation. Higher adhesion and biofilm formation was noted in both organisms in the presence of d-carbohydrates relative to their l-carbohydrate counterparts. These results elucidate, hitherto undescribed, interactions of the individually tested strains with l- and d-carbohydrates, and how they impact fungal and bacterial colonization. In translational terms, our data raise the possibility of using l-form of carbohydrates and xylitol for dietary control of oral plaque biofilms. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Orchestration of carbohydrate processing for crassulacean acid metabolism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borland, Anne M.; Guo, Hao-Bo; Yang, Xiaohan

The production of phosphoenolpyruvate as a substrate for nocturnal CO 2 uptake represents a significant sink for carbohydrate in CAM plants which has to be balanced with the provisioning of carbohydrate for growth and maintenance. In starch-storing CAM species, diversification in chloroplast metabolite transporters, and the deployment of both phosphorolytic and hydrolytic routes of starch degradation accommodate a division of labour in directing C-skeletons towards nocturnal carboxylation or production of sucrose for growth. In soluble-sugar storing CAM plants, the vacuole plays a central role in managing carbon homeostasis. The molecular identities of various types of vacuolar sugar transporters have onlymore » been identified for C 3 species within the last 10 years. In conclusion, the recent availability of CAM genomes enables the identification of putative orthologues of vacuolar sugar transporters which represent strategic targets for orchestrating the diel provisioning of substrate for nocturnal carboxylation and growth.« less

Orchestration of carbohydrate processing for crassulacean acid metabolism

DOE PAGES

Borland, Anne M.; Guo, Hao-Bo; Yang, Xiaohan; ...

2016-04-19

The production of phosphoenolpyruvate as a substrate for nocturnal CO 2 uptake represents a significant sink for carbohydrate in CAM plants which has to be balanced with the provisioning of carbohydrate for growth and maintenance. In starch-storing CAM species, diversification in chloroplast metabolite transporters, and the deployment of both phosphorolytic and hydrolytic routes of starch degradation accommodate a division of labour in directing C-skeletons towards nocturnal carboxylation or production of sucrose for growth. In soluble-sugar storing CAM plants, the vacuole plays a central role in managing carbon homeostasis. The molecular identities of various types of vacuolar sugar transporters have onlymore » been identified for C 3 species within the last 10 years. In conclusion, the recent availability of CAM genomes enables the identification of putative orthologues of vacuolar sugar transporters which represent strategic targets for orchestrating the diel provisioning of substrate for nocturnal carboxylation and growth.« less

Multivalency at Interfaces: Supramolecular Carbohydrate-Functionalized Graphene Derivatives for Bacterial Capture, Release, and Disinfection.

PubMed

Qi, Zhenhui; Bharate, Priya; Lai, Chian-Hui; Ziem, Benjamin; Böttcher, Christoph; Schulz, Andrea; Beckert, Fabian; Hatting, Benjamin; Mülhaupt, Rolf; Seeberger, Peter H; Haag, Rainer

2015-09-09

A supramolecular carbohydrate-functionalized two-dimensional (2D) surface was designed and synthesized by decorating thermally reduced graphene sheets with multivalent sugar ligands. The formation of host-guest inclusions on the carbon surface provides a versatile strategy, not only to increase the intrinsic water solubility of graphene-based materials, but more importantly to let the desired biofunctional binding groups bind to the surface. Combining the vital recognition role of carbohydrates and the unique 2D large flexible surface area of the graphene sheets, the addition of multivalent sugar ligands makes the resulting carbon material an excellent platform for selectively wrapping and agglutinating Escherichia coli (E. coli). By taking advantage of the responsive property of supramolecular interactions, the captured bacteria can then be partially released by adding a competitive guest. Compared to previously reported scaffolds, the unique thermal IR-absorption properties of graphene derivatives provide a facile method to kill the captured bacteria by IR-laser irradiation of the captured graphene-sugar-E. coli complex.

Structural basis of mammalian glycan targeting by Vibrio cholerae cytolysin and biofilm proteins

PubMed Central

De, Swastik; Kaus, Katherine; Sinclair, Shada

2018-01-01

Vibrio cholerae is an aquatic gram-negative microbe responsible for cholera, a pandemic disease causing life-threatening diarrheal outbreaks in populations with limited access to health care. Like most pathogenic bacteria, V. cholerae secretes virulence factors to assist colonization of human hosts, several of which bind carbohydrate receptors found on cell-surfaces. Understanding how pathogenic virulence proteins specifically target host cells is important for the development of treatment strategies to fight bacterial infections. Vibrio cholerae cytolysin (VCC) is a secreted pore-forming toxin with a carboxy-terminal β-prism domain that targets complex N-glycans found on mammalian cell-surface proteins. To investigate glycan selectivity, we studied the VCC β-prism domain and two additional β-prism domains found within the V. cholerae biofilm matrix protein RbmC. We show that the two RbmC β-prism domains target a similar repertoire of complex N-glycan receptors as VCC and find through binding and modeling studies that a branched pentasaccharide core (GlcNAc2-Man3) represents the likely footprint interacting with these domains. To understand the structural basis of V. cholerae β-prism selectivity, we solved high-resolution crystal structures of fragments of the pentasaccharide core bound to one RbmC β-prism domain and conducted mutagenesis experiments on the VCC toxin. Our results highlight a common strategy for cell-targeting utilized by both toxin and biofilm matrix proteins in Vibrio cholerae and provide a structural framework for understanding the specificity for individual receptors. Our results suggest that a common strategy for disrupting carbohydrate interactions could affect multiple virulence factors produced by V. cholerae, as well as similar β-prism domains found in other vibrio pathogens. PMID:29432487

Predicting water-soluble carbohydrates and ethanol-soluble carbohydrates in cool-season grasses with near-infrared reflectance spectroscopy

USDA-ARS?s Scientific Manuscript database

Grazing animals may require a high or low total nonstructural carbohydrate diet for optimal health and production. Understanding how nonstructural carbohydrates fluctuate in Kentucky pastures and being able to quantify and monitor nonstructural carbohydrates in a timely manner will greatly aid in m...

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice

PubMed Central

Underwood, Graham J. C.; Aslam, Shazia N.; Michel, Christine; Niemi, Andrea; Norman, Louiza; Meiners, Klaus M.; Laybourn-Parry, Johanna; Paterson, Harriet; Thomas, David N.

2013-01-01

Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions. PMID:24019487

Broad-scale predictability of carbohydrates and exopolymers in Antarctic and Arctic sea ice.

PubMed

Underwood, Graham J C; Aslam, Shazia N; Michel, Christine; Niemi, Andrea; Norman, Louiza; Meiners, Klaus M; Laybourn-Parry, Johanna; Paterson, Harriet; Thomas, David N

2013-09-24

Sea ice can contain high concentrations of dissolved organic carbon (DOC), much of which is carbohydrate-rich extracellular polymeric substances (EPS) produced by microalgae and bacteria inhabiting the ice. Here we report the concentrations of dissolved carbohydrates (dCHO) and dissolved EPS (dEPS) in relation to algal standing stock [estimated by chlorophyll (Chl) a concentrations] in sea ice from six locations in the Southern and Arctic Oceans. Concentrations varied substantially within and between sampling sites, reflecting local ice conditions and biological content. However, combining all data revealed robust statistical relationships between dCHO concentrations and the concentrations of different dEPS fractions, Chl a, and DOC. These relationships were true for whole ice cores, bottom ice (biomass rich) sections, and colder surface ice. The distribution of dEPS was strongly correlated to algal biomass, with the highest concentrations of both dEPS and non-EPS carbohydrates in the bottom horizons of the ice. Complex EPS was more prevalent in colder surface sea ice horizons. Predictive models (validated against independent data) were derived to enable the estimation of dCHO concentrations from data on ice thickness, salinity, and vertical position in core. When Chl a data were included a higher level of prediction was obtained. The consistent patterns reflected in these relationships provide a strong basis for including estimates of regional and seasonal carbohydrate and dEPS carbon budgets in coupled physical-biogeochemical models, across different types of sea ice from both polar regions.

From 'pleasure to chemistry': the experience of carbohydrate counting with and without carbohydrate restriction for people with Type 1 diabetes.

PubMed

Cresswell, Pip; Krebs, Jeremy; Gilmour, Jean; Hanna, Aoife; Parry-Strong, Amber

2015-12-01

Matching carbohydrate intake with insulin dosage is recommended management for people with Type 1 diabetes. However, international interest in restricted carbohydrate diets is growing. General practitioners and practice nurses need to know how to advise people with Type 1 diabetes regarding low-carbohydrate diets. This study aimed to explore the carbohydrate counting experiences of people with Type 1 diabetes in a trial with and without a diet restricted to 75 g of carbohydrate per day. Eight participants were interviewed by focus group or interview 12 weeks after a carbohydrate counting course with individual dietary choice or the same course with information on restricted carbohydrate eating and a daily maximum intake of 75 g of carbohydrate. Data were analysed using a qualitative thematic analysis approach. Themes included the need for insulin management skills, impact of the dietary experience, and need for dietary knowledge. The restricted-carbohydrate group encountered mealtime insulin resistance and difficulty managing insulin dosages when transitioning on and off the low-carbohydrate diet. The diet impacted on mood, feelings of satiety and it was reported that food changed from being 'a pleasure to chemistry'. Both groups described feeling empowered to manage their diabetes as a result of the carbohydrate counting course. Participants reported increased knowledge and challenging insulin management. The restricted-carbohydrate group reported mealtime insulin resistance and a strong dietary impact. Extra health professional support may be required, especially at dietary transition periods. More research is warranted into the reported mealtime insulin resistance.

Discovery and design of carbohydrate-based therapeutics.

PubMed

Cipolla, Laura; Araújo, Ana C; Bini, Davide; Gabrielli, Luca; Russo, Laura; Shaikh, Nasrin

2010-08-01

Till now, the importance of carbohydrates has been underscored, if compared with the two other major classes of biopolymers such as oligonucleotides and proteins. Recent advances in glycobiology and glycochemistry have imparted a strong interest in the study of this enormous family of biomolecules. Carbohydrates have been shown to be implicated in recognition processes, such as cell-cell adhesion, cell-extracellular matrix adhesion and cell-intruder recognition phenomena. In addition, carbohydrates are recognized as differentiation markers and as antigenic determinants. Due to their relevant biological role, carbohydrates are promising candidates for drug design and disease treatment. However, the growing number of human disorders known as congenital disorders of glycosylation that are being identified as resulting from abnormalities in glycan structures and protein glycosylation strongly indicates that a fast development of glycobiology, glycochemistry and glycomedicine is highly desirable. The topics give an overview of different approaches that have been used to date for the design of carbohydrate-based therapeutics; this includes the use of native synthetic carbohydrates, the use of carbohydrate mimics designed on the basis of their native counterpart, the use of carbohydrates as scaffolds and finally the design of glyco-fused therapeutics, one of the most recent approaches. The review covers mainly literature that has appeared since 2000, except for a few papers cited for historical reasons. The reader will gain an overview of the current strategies applied to the design of carbohydrate-based therapeutics; in particular, the advantages/disadvantages of different approaches are highlighted. The topic is presented in a general, basic manner and will hopefully be a useful resource for all readers who are not familiar with it. In addition, in order to stress the potentialities of carbohydrates, several examples of carbohydrate-based marketed therapeutics are given

Statistical analysis of the Bacterial Carbohydrate Structure Data Base (BCSDB): Characteristics and diversity of bacterial carbohydrates in comparison with mammalian glycans

PubMed Central

Herget, Stephan; Toukach, Philip V; Ranzinger, René; Hull, William E; Knirel, Yuriy A; von der Lieth, Claus-Wilhelm

2008-01-01

Background There are considerable differences between bacterial and mammalian glycans. In contrast to most eukaryotic carbohydrates, bacterial glycans are often composed of repeating units with diverse functions ranging from structural reinforcement to adhesion, colonization and camouflage. Since bacterial glycans are typically displayed at the cell surface, they can interact with the environment and, therefore, have significant biomedical importance. Results The sequence characteristics of glycans (monosaccharide composition, modifications, and linkage patterns) for the higher bacterial taxonomic classes have been examined and compared with the data for mammals, with both similarities and unique features becoming evident. Compared to mammalian glycans, the bacterial glycans deposited in the current databases have a more than ten-fold greater diversity at the monosaccharide level, and the disaccharide pattern space is approximately nine times larger. Specific bacterial subclasses exhibit characteristic glycans which can be distinguished on the basis of distinctive structural features or sequence properties. Conclusion For the first time a systematic database analysis of the bacterial glycome has been performed. This study summarizes the current knowledge of bacterial glycan architecture and diversity and reveals putative targets for the rational design and development of therapeutic intervention strategies by comparing bacterial and mammalian glycans. PMID:18694500

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization.

PubMed

Rodríguez-Viera, Leandro; Perera, Erick; Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M

2017-01-01

As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus . We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes.

Carbohydrates digestion and metabolism in the spiny lobster (Panulirus argus): biochemical indication for limited carbohydrate utilization

PubMed Central

Montero-Alejo, Vivian; Perdomo-Morales, Rolando; García-Galano, Tsai; Martínez-Rodríguez, Gonzalo; Mancera, Juan M.

2017-01-01

As other spiny lobsters, Panulirus argus is supposed to use preferentially proteins and lipids in energy metabolism, while carbohydrates are well digested but poorly utilized. The aim of this study was to evaluate the effect of dietary carbohydrate level on digestion and metabolism in the spiny lobster P. argus. We used complementary methodologies such as post-feeding flux of nutrients and metabolites, as well as measurements of α-amylase expression and activity in the digestive tract. Lobsters readily digested and absorbed carbohydrates with a time-course that is dependent on their content in diet. Lobster showed higher levels of free glucose and stored glycogen in different tissues as the inclusion of wheat flour increased. Modifications in intermediary metabolism revealed a decrease in amino acids catabolism coupled with a higher use of free glucose as carbohydrates rise up to 20%. However, this effect seems to be limited by the metabolic capacity of lobsters to use more than 20% of carbohydrates in diets. Lobsters were not able to tightly regulate α-amylase expression according to dietary carbohydrate level but exhibited a marked difference in secretion of this enzyme into the gut. Results are discussed to highlight the limitations to increasing carbohydrate utilization by lobsters. Further growout trials are needed to link the presented metabolic profiles with phenotypic outcomes. PMID:29114440

Surface Functionalization and Targeting Strategies of Liposomes in Solid Tumor Therapy: A Review

PubMed Central

Riaz, Muhammad Kashif; Riaz, Muhammad Adil; Zhang, Xue; Lin, Congcong; Wong, Ka Hong; Chen, Xiaoyu; Lu, Aiping

2018-01-01

Surface functionalization of liposomes can play a key role in overcoming the current limitations of nanocarriers to treat solid tumors, i.e., biological barriers and physiological factors. The phospholipid vesicles (liposomes) containing anticancer agents produce fewer side effects than non-liposomal anticancer formulations, and can effectively target the solid tumors. This article reviews information about the strategies for targeting of liposomes to solid tumors along with the possible targets in cancer cells, i.e., extracellular and intracellular targets and targets in tumor microenvironment or vasculature. Targeting ligands for functionalization of liposomes with relevant surface engineering techniques have been described. Stimuli strategies for enhanced delivery of anticancer agents at requisite location using stimuli-responsive functionalized liposomes have been discussed. Recent approaches for enhanced delivery of anticancer agents at tumor site with relevant surface functionalization techniques have been reviewed. Finally, current challenges of functionalized liposomes and future perspective of smart functionalized liposomes have been discussed. PMID:29315231

Carbohydrates and Endothelial Function: Is a Low-Carbohydrate Diet or a Low-Glycemic Index Diet Favourable for Vascular Health?

PubMed Central

Jovanovski, Elena; Zurbau, Andreea

2015-01-01

Low-carbohydrate diets have become increasingly popular in both media and clinical research settings. Although they may improve some metabolic markers, their effects on arterial function remain unclear. Endothelial dysfunction is the well-established response to cardiovascular risk factors and a pivotal feature that precedes atherosclerotic diseases. It has been demonstrated that a high carbohydrate-induced hyperglycemia and subsequent oxidative stress acutely worsen the efficacy of the endothelial vasodilatory system. Thus, in theory, a carbohydrate restricted diet may preserve the integrity of the arterial system. This review attempts to provide insight on whether low-carbohydrate diets have a favorable or detrimental impact on vascular function, or it is perhaps the quality of carbohydrate that should direct dietary recommendations. Research to date suggests that diets low in carbohydrate amount may negatively impact vascular endothelial function. Conversely, it appears that maintaining recommended carbohydrate intake with utilization of low glycemic index foods generates a more favorable vascular profile. Understanding these relationships will aid in deciphering the diverging role of modulating quantity and quality of carbohydrates on cardiovascular risk. PMID:25954727

Carbohydrates and endothelial function: is a low-carbohydrate diet or a low-glycemic index diet favourable for vascular health?

PubMed

Jovanovski, Elena; Zurbau, Andreea; Vuksan, Vladimir

2015-04-01

Low-carbohydrate diets have become increasingly popular in both media and clinical research settings. Although they may improve some metabolic markers, their effects on arterial function remain unclear. Endothelial dysfunction is the well-established response to cardiovascular risk factors and a pivotal feature that precedes atherosclerotic diseases. It has been demonstrated that a high carbohydrate-induced hyperglycemia and subsequent oxidative stress acutely worsen the efficacy of the endothelial vasodilatory system. Thus, in theory, a carbohydrate restricted diet may preserve the integrity of the arterial system. This review attempts to provide insight on whether low-carbohydrate diets have a favorable or detrimental impact on vascular function, or it is perhaps the quality of carbohydrate that should direct dietary recommendations. Research to date suggests that diets low in carbohydrate amount may negatively impact vascular endothelial function. Conversely, it appears that maintaining recommended carbohydrate intake with utilization of low glycemic index foods generates a more favorable vascular profile. Understanding these relationships will aid in deciphering the diverging role of modulating quantity and quality of carbohydrates on cardiovascular risk.

Protein flexibility and conformational entropy in ligand design targeting the carbohydrate recognition domain of galectin-3.

PubMed

Diehl, Carl; Engström, Olof; Delaine, Tamara; Håkansson, Maria; Genheden, Samuel; Modig, Kristofer; Leffler, Hakon; Ryde, Ulf; Nilsson, Ulf J; Akke, Mikael

2010-10-20

Rational drug design is predicated on knowledge of the three-dimensional structure of the protein-ligand complex and the thermodynamics of ligand binding. Despite the fundamental importance of both enthalpy and entropy in driving ligand binding, the role of conformational entropy is rarely addressed in drug design. In this work, we have probed the conformational entropy and its relative contribution to the free energy of ligand binding to the carbohydrate recognition domain of galectin-3. Using a combination of NMR spectroscopy, isothermal titration calorimetry, and X-ray crystallography, we characterized the binding of three ligands with dissociation constants ranging over 2 orders of magnitude. (15)N and (2)H spin relaxation measurements showed that the protein backbone and side chains respond to ligand binding by increased conformational fluctuations, on average, that differ among the three ligand-bound states. Variability in the response to ligand binding is prominent in the hydrophobic core, where a distal cluster of methyl groups becomes more rigid, whereas methyl groups closer to the binding site become more flexible. The results reveal an intricate interplay between structure and conformational fluctuations in the different complexes that fine-tunes the affinity. The estimated change in conformational entropy is comparable in magnitude to the binding enthalpy, demonstrating that it contributes favorably and significantly to ligand binding. We speculate that the relatively weak inherent protein-carbohydrate interactions and limited hydrophobic effect associated with oligosaccharide binding might have exerted evolutionary pressure on carbohydrate-binding proteins to increase the affinity by means of conformational entropy.

Conversion of carbohydrate into hydrogen fuel by a photocatalytic process

NASA Astrophysics Data System (ADS)

Kawai, T.; Sakata, T.

1980-07-01

A photocatalytic process for the conversion of carbohydrates into hydrogen fuel is presented. The method involves the irradiation of sugar, starch or cellulose in the presence of water and a RuO2/TiO2/Pt catalyst, which has been found to lead to the generation of CO2 and H2 at efficiencies 100 times larger than those obtained with TiO2 alone, with no detectable amounts of other products. The reaction mechanism can be explained in terms of an electrochemical microcell, in which electron-hole pairs generated in TiO2 cause redox reactions at the surface. The process may thus be used in the conversion of solar energy stored in the form of carbohydrates by green plant photosynthesis into useful hydrogen fuels.

Accuracy of Carbohydrate Counting in Adults

PubMed Central

Rushton, Wanda E.

2016-01-01

In Brief This study investigates carbohydrate counting accuracy in patients using insulin through a multiple daily injection regimen or continuous subcutaneous insulin infusion. The average accuracy test score for all patients was 59%. The carbohydrate test in this study can be used to emphasize the importance of carbohydrate counting to patients and to provide ongoing education. PMID:27621531

Thiol-ene immobilisation of carbohydrates onto glass slides as a simple alternative to gold-thiol monolayers, amines or lipid binding.

PubMed

Biggs, Caroline I; Edmondson, Steve; Gibson, Matthew I

2015-01-01

Carbohydrate arrays are a vital tool in studying infection, probing the mechanisms of bacterial, viral and toxin adhesion and the development of new treatments, by mimicking the structure of the glycocalyx. Current methods rely on the formation of monolayers of carbohydrates that have been chemically modified with a linker to enable interaction with a functionalised surface. This includes amines, biotin, lipids or thiols. Thiol-addition to gold to form self-assembled monolayers is perhaps the simplest method for immobilisation as thiolated glycans are readily accessible from reducing carbohydrates in a single step, but are limited to gold surfaces. Here we have developed a quick and versatile methodology which enables the use of thiolated carbohydrates to be immobilised as monolayers directly onto acrylate-functional glass slides via a 'thiol-ene'/Michael-type reaction. By combining the ease of thiol chemistry with glass slides, which are compatible with microarray scanners this offers a cost effective, but also useful method to assemble arrays.

Sensing specific adhesion of liposomal and micellar systems with attached carbohydrate recognition structures at lectin surfaces.

PubMed

Hildebrand, Annegret; Schaedlich, Anita; Rothe, Ulrich; Neubert, Reinhard H H

2002-05-15

A quartz crystal microbalance was used to investigate the adsorption behavior of liposomes and mixed micelles with attached carbohydrate recognition structures at lectin-coated quartz plates. With a self-assembly technique, the quartz was coated with the lectin Concanavalin A. In a first attempt, liposomes of natural soybean PC as well as synthetic POPC, containing 10% reactive N-Glut-PE each, were decorated with a mannopyranoside recognition structure to investigate the specific adsorption at the lectin-coated quartz surface in dependence on the concentration. In a second model, the bile salt sodium cholate was introduced to solubilize the mannopyranoside-modified liposomes and to transform them into mannopyranoside-modified binary mixed micelles. The adsorption of these micelles was further investigated. In a third approach, the adsorption behavior of mannopyranoside-modified ternary mixed bile salt-phosphatidylcholine-fatty acid micelles was characterized with sodium laurate, palmitate, and oleate as fatty acids. The micelles with oleate showed only a small frequency decrease, whereas the micelles with laurate and palmitate induced higher frequency changes. A dependence on the alkyl chain length could be detected. While the adsorption of liposomes containing recognition structures at QCM surfaces is nowadays well-established, the QCM detection of the adsorption of mixed bile salt micelles, transformed from these liposomes by solubilization, is a novel and very promising field for the development of innovative colloidal drug delivery systems.

Anti-Cancer Drug Delivery Using Carbohydrate-Based Polymers.

PubMed

Ranjbari, Javad; Mokhtarzadeh, Ahad; Alibakhshi, Abbas; Tabarzad, Maryam; Hejazi, Maryam; Ramezani, Mohammad

2018-02-12

Polymeric drug delivery systems in the form of nanocarriers are the most interesting vehicles in anticancer therapy. Among different types of biocompatible polymers, carbohydrate-based polymers or polysaccharides are the most common natural polymers with complex structures consisting of long chains of monosaccharide or disaccharide units bound by glycosidic linkages. Their appealing properties such as availability, biocompatibility, biodegradability, low toxicity, high chemical reactivity, facile chemical modification and low cost led to their extensive applications in biomedical and pharmaceutical fields including development of nano-vehicles for delivery of anti-cancer therapeutic agents. Generally, reducing systemic toxicity, increasing short half-lives and tumor localization of agents are the top priorities for a successful cancer therapy. Polysaccharide-based or - coated nanosystems with respect to their advantageous features as well as accumulation in tumor tissue due to enhanced permeation and retention (EPR) effect can provide promising carrier systems for the delivery of noblest impressive agents. Most challenging factor in cancer therapy was the toxicity of anti-cancer therapeutic agents for normal cells and therefore, targeted delivery of these drugs to the site of action can be considered as an interesting therapeutic strategy. In this regard, several polysaccharides exhibited selective affinity for specific cell types, and so they can act as a targeting agent in drug delivery systems. Accordingly, different aspects of polysaccharide applications in cancer treatment or diagnosis were reviewed in this paper. In this regard, after a brief introduction of polysaccharide structure and its importance, the pharmaceutical usage of carbohydrate-based polymers was considered according to the identity of accompanying active pharmaceutical agents. It was also presented that the carbohydrate based polymers have been extensively considered as promising materials in

Surface heat loads on the ITER divertor vertical targets

NASA Astrophysics Data System (ADS)

Gunn, J. P.; Carpentier-Chouchana, S.; Escourbiac, F.; Hirai, T.; Panayotis, S.; Pitts, R. A.; Corre, Y.; Dejarnac, R.; Firdaouss, M.; Kočan, M.; Komm, M.; Kukushkin, A.; Languille, P.; Missirlian, M.; Zhao, W.; Zhong, G.

2017-04-01

The heating of tungsten monoblocks at the ITER divertor vertical targets is calculated using the heat flux predicted by three-dimensional ion orbit modelling. The monoblocks are beveled to a depth of 0.5 mm in the toroidal direction to provide magnetic shadowing of the poloidal leading edges within the range of specified assembly tolerances, but this increases the magnetic field incidence angle resulting in a reduction of toroidal wetted fraction and concentration of the local heat flux to the unshadowed surfaces. This shaping solution successfully protects the leading edges from inter-ELM heat loads, but at the expense of (1) temperatures on the main loaded surface that could exceed the tungsten recrystallization temperature in the nominal partially detached regime, and (2) melting and loss of margin against critical heat flux during transient loss of detachment control. During ELMs, the risk of monoblock edge melting is found to be greater than the risk of full surface melting on the plasma-wetted zone. Full surface and edge melting will be triggered by uncontrolled ELMs in the burning plasma phase of ITER operation if current models of the likely ELM ion impact energies at the divertor targets are correct. During uncontrolled ELMs in pre-nuclear deuterium or helium plasmas at half the nominal plasma current and magnetic field, full surface melting should be avoided, but edge melting is predicted.

Electronic Detection of Lectins Using Carbohydrate Functionalized Nanostructures: Graphene versus Carbon Nanotubes

PubMed Central

Chen, Yanan; Vedala, Harindra; Kotchey, Gregg P.; Audfray, Aymeric; Cecioni, Samy; Imberty, Anne; Vidal, Sébastien; Star, Alexander

2012-01-01

Here we investigated the interactions between lectins and carbohydrates using field-effect transistor (FET) devices comprised of chemically converted graphene (CCG) and single-walled carbon nanotubes (SWNTs). Pyrene- and porphyrin-based glycoconjugates were functionalized noncovalently on the surface of CCG-FET and SWNT-FET devices, which were then treated with 2 µM of nonspecific and specific lectins. In particular, three different lectins (PA-IL, PA-IIL and ConA) and three carbohydrate epitopes (galactose, fucose and mannose) were tested. The responses of 36 different devices were compared and rationalized using computer-aided models of carbon nanostructure/glycoconjugate interactions. Glycoconjugates surface coverage in addition to one-dimensional structures of SWNTs resulted in optimal lectin detection. Additionally, lectin titration data of SWNT- and CCG-based biosensors were used to calculate lectin dissociation constants (Kd) and compare them to the values obtained from the isothermal titration microcalorimetry (ITC) technique. PMID:22136380

Preparation of water-soluble glycoconjugated poly(acrylamide) for NMR analyses of carbohydrate-carbohydrate interactions

NASA Astrophysics Data System (ADS)

Xuan, Trinh Anh; Trung, Phan Nghia; Dinh, Bui Long; Yamaguchi, Takumi; Kato, Koichi

2014-05-01

Oligosaccharide chains of glycoconjugates are important biopolymers not only as carriers of information in cell-cell interactions but also as markers of cellular differentiation, aging, and malignant alteration. Molecular interactions where carbohydrates are involved are usually considered as weak interactions, so the study and evaluation of these interactions is still in its infancy. The evidences and studies of carbohydrate-carbohydrate interactions (CCI) will be confirming the importance of this mechanism for specific cell adhesion and communication. Their development will go hand in hand with the development of new and more sensitive techniques to study weak interactions. Recently, synthetic glycopolymers with functions similar to those of such natural carbohydrates and with specific pendant saccharide moieties were used as a solution for enhancement CCI when forming polyvalent interactions. Carbohydrates are ubiquitous components of cell wall membranes and occur as glycolipids, glycoproteins, proteoglycans, and capsular polysaccharides. As such they can participate in forefront intramolecular and intracellular events. Apart from their recognized roles in the physicochemical properties of glycolipids and glycoproteins. In this study, we designed trisaccharide monomers for free radical polymerization. Subsequently, the trisaccharide unit for chemical conjugation was synthesized from galactosamine in good yield. For further NMR analyses of CCI, glycopolymers composed of these sugar derivatives will be provided.

Evidence that family 35 carbohydrate binding modules display conserved specificity but divergent function

PubMed Central

Montanier, Cedric; van Bueren, Alicia Lammerts; Dumon, Claire; Flint, James E.; Correia, Marcia A.; Prates, Jose A.; Firbank, Susan J.; Lewis, Richard J.; Grondin, Gilles G.; Ghinet, Mariana G.; Gloster, Tracey M.; Herve, Cecile; Knox, J. Paul; Talbot, Brian G.; Turkenburg, Johan P.; Kerovuo, Janne; Brzezinski, Ryszard; Fontes, Carlos M. G. A.; Davies, Gideon J.; Boraston, Alisdair B.; Gilbert, Harry J.

2009-01-01

Enzymes that hydrolyze complex carbohydrates play important roles in numerous biological processes that result in the maintenance of marine and terrestrial life. These enzymes often contain noncatalytic carbohydrate binding modules (CBMs) that have important substrate-targeting functions. In general, there is a tight correlation between the ligands recognized by bacterial CBMs and the substrate specificity of the appended catalytic modules. Through high-resolution structural studies, we demonstrate that the architecture of the ligand binding sites of 4 distinct family 35 CBMs (CBM35s), appended to 3 plant cell wall hydrolases and the exo-β-d-glucosaminidase CsxA, which contributes to the detoxification and metabolism of an antibacterial fungal polysaccharide, is highly conserved and imparts specificity for glucuronic acid and/or Δ4,5-anhydrogalaturonic acid (Δ4,5-GalA). Δ4,5-GalA is released from pectin by the action of pectate lyases and as such acts as a signature molecule for plant cell wall degradation. Thus, the CBM35s appended to the 3 plant cell wall hydrolases, rather than targeting the substrates of the cognate catalytic modules, direct their appended enzymes to regions of the plant that are being actively degraded. Significantly, the CBM35 component of CsxA anchors the enzyme to the bacterial cell wall via its capacity to bind uronic acid sugars. This latter observation reveals an unusual mechanism for bacterial cell wall enzyme attachment. This report shows that the biological role of CBM35s is not dictated solely by their carbohydrate specificities but also by the context of their target ligands. PMID:19218457

Change in food cravings, food preferences, and appetite during a low-carbohydrate and low-fat diet

PubMed Central

Martin, C. K.; Rosenbaum, D.; Han, H.; Geiselman, P.; Wyatt, H.; Hill, J.; Brill, C.; Bailer, B.; Miller, B. V.; Stein, R.; Klein, S.; Foster, Gard D.

2011-01-01

The study objective was to evaluate the effect of prescribing a low-carbohydrate diet (LCD) and a low-fat diet (LFD) on food cravings, food preferences, and appetite. Obese adults were randomly assigned to a LCD (n=134) or a LFD (n=136) for two years. Cravings for specific types of foods (sweets, high-fats, fast-food fats, carbohydrates/starches); preferences for high-sugar, high-carbohydrate, and low-carbohydrate/high-protein foods; and appetite were measured during the trial and evaluated during this secondary analysis of trial data. Differences between the LCD and LFD on change in outcome variables were examined with mixed linear models. Compared to the LFD, the LCD had significantly larger decreases in cravings for carbohydrates/starches and preferences for high-carbohydrate and high-sugar foods. The LCD group reported being less bothered by hunger compared to the LFD group. Compared to the LCD group, the LFD group had significantly larger decreases in cravings for high-fat foods and preference for low-carbohydrate/high-protein foods. Men had larger decreases in appetite ratings compared to women. Prescription of diets that promoted restriction of specific types of foods resulted in decreased cravings and preferences for the foods that were targeted for restriction. The results also indicate that the LCD group was less bothered by hunger compared to the LFD group and that men had larger reductions in appetite compared to women. PMID:21494226

Tailoring the charged particle fluxes across the target surface of Magnum-PSI

NASA Astrophysics Data System (ADS)

Costin, C.; Anita, V.; Popa, G.; Scholten, J.; De Temmerman, G.

2016-04-01

Linear plasma generators are plasma devices designed to study fusion-relevant plasma-surface interactions. The first requirement for such devices is to operate with adjustable and well characterized plasma parameters. In the linear plasma device Magnum-PSI, the distribution of the charged particle flux across the target surface can be tailored by the target bias. The process is based on the radial inhomogeneity of the plasma column and it is evidenced by electrical measurements via a 2D multi-probe system installed as target. Typical results are reported for a hydrogen discharge operated at 125 A and confined by a magnetic field strength of 0.95 T in the middle of the coils. The probes were biased in the range of  -80 to  -25 V, while the floating potential of the target was about  -35 V. The results were obtained in steady-state regime of Magnum-PSI, being time-averaged over any type of fluctuations. Depending on the relative value of the target bias voltage with respect to the local floating potential in the plasma column, the entire target surface can be exposed to ion or electron dominated flux, respectively, or it can be divided into two adjacent zones: one exposed to electron flux and the other to ion flux. As a consequence of this effect, a floating conductive surface that interacts with an inhomogeneous plasma is exposed to non-zero local currents despite its overall null current and it is subjected to internal current flows.

Exploiting Uniformly 13C-Labeled Carbohydrates for Probing Carbohydrate-Protein Interactions by NMR Spectroscopy.

PubMed

Nestor, Gustav; Anderson, Taigh; Oscarson, Stefan; Gronenborn, Angela M

2017-05-03

NMR of a uniformly 13 C-labeled carbohydrate was used to elucidate the atomic details of a sugar-protein complex. The structure of the 13 C-labeled Manα(1-2)Manα(1-2)ManαOMe trisaccharide ligand, when bound to cyanovirin-N (CV-N), was characterized and revealed that in the complex the glycosidic linkage torsion angles between the two reducing-end mannoses are different from the free trisaccharide. Distances within the carbohydrate were employed for conformational analysis, and NOE-based distance mapping between sugar and protein revealed that Manα(1-2)Manα(1-2)ManαOMe is bound more intimately with its two reducing-end mannoses into the domain A binding site of CV-N than with the nonreducing end unit. Taking advantage of the 13 C spectral dispersion of 13 C-labeled carbohydrates in isotope-filtered experiments is a versatile means for a simultaneous mapping of the binding interactions on both, the carbohydrate and the protein.

Environmental Stability of Seed Carbohydrate Profiles in Soybeans Containing Different Alleles of the Raffinose Synthase 2 (RS2) Gene.

PubMed

Bilyeu, Kristin D; Wiebold, William J

2016-02-10

Soybean [Glycine max (L.) Merr.] is important for the high protein meal used for livestock feed formulations. Carbohydrates contribute positively or negatively to the potential metabolizable energy in soybean meal. The positive carbohydrate present in soybean meal consists primarily of sucrose, whereas the negative carbohydrate components are the raffinose family of oligosaccharides (RFOs), raffinose and stachyose. Increasing sucrose and decreasing raffinose and stachyose are critical targets to improve soybean. In three recently characterized lines, variant alleles of the soybean raffinose synthase 2 (RS2) gene were associated with increased sucrose and decreased RFOs. The objective of this research was to compare the environmental stability of seed carbohydrates in soybean lines containing wild-type or variant alleles of RS2 utilizing a field location study and a date of planting study. The results define the carbohydrate variation in distinct regional and temporal environments using soybean lines with different alleles of the RS2 gene.

Force fields and scoring functions for carbohydrate simulation.

PubMed

Xiong, Xiuming; Chen, Zhaoqiang; Cossins, Benjamin P; Xu, Zhijian; Shao, Qiang; Ding, Kai; Zhu, Weiliang; Shi, Jiye

2015-01-12

Carbohydrate dynamics plays a vital role in many biological processes, but we are not currently able to probe this with experimental approaches. The highly flexible nature of carbohydrate structures differs in many aspects from other biomolecules, posing significant challenges for studies employing computational simulation. Over past decades, computational study of carbohydrates has been focused on the development of structure prediction methods, force field optimization, molecular dynamics simulation, and scoring functions for carbohydrate-protein interactions. Advances in carbohydrate force fields and scoring functions can be largely attributed to enhanced computational algorithms, application of quantum mechanics, and the increasing number of experimental structures determined by X-ray and NMR techniques. The conformational analysis of carbohydrates is challengeable and has gone into intensive study in elucidating the anomeric, the exo-anomeric, and the gauche effects. Here, we review the issues associated with carbohydrate force fields and scoring functions, which will have a broad application in the field of carbohydrate-based drug design. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multi-surface topography targeted plateau honing for the processing of cylinder liner surfaces of automotive engines

NASA Astrophysics Data System (ADS)

Lawrence, K. Deepak; Ramamoorthy, B.

2016-03-01

Cylinder bores of automotive engines are 'engineered' surfaces that are processed using multi-stage honing process to generate multiple layers of micro geometry for meeting the different functional requirements of the piston assembly system. The final processed surfaces should comply with several surface topographic specifications that are relevant for the good tribological performance of the engine. Selection of the process parameters in three stages of honing to obtain multiple surface topographic characteristics simultaneously within the specification tolerance is an important module of the process planning and is often posed as a challenging task for the process engineers. This paper presents a strategy by combining the robust process design and gray-relational analysis to evolve the operating levels of honing process parameters in rough, finish and plateau honing stages targeting to meet multiple surface topographic specifications on the final running surface of the cylinder bores. Honing experiments were conducted in three stages namely rough, finish and plateau honing on cast iron cylinder liners by varying four honing process parameters such as rotational speed, oscillatory speed, pressure and honing time. Abbott-Firestone curve based functional parameters (Rk, Rpk, Rvk, Mr1 and Mr2) coupled with mean roughness depth (Rz, DIN/ISO) and honing angle were measured and identified as the surface quality performance targets to be achieved. The experimental results have shown that the proposed approach is effective to generate cylinder liner surface that would simultaneously meet the explicit surface topographic specifications currently practiced by the industry.

Separation and quantitation of plant and insect carbohydrate isomers found on the surface of cotton

USDA-ARS?s Scientific Manuscript database

Cotton stickiness researchers have worked to create ion chromatography (IC) carbohydrate separation methods which allow for minimal analysis time and reduced operational costs. Researchers have also tried to correlate scientifically backed IC data with the available physical stickiness tests, such ...

Quantum dots assisted laser desorption/ionization mass spectrometric detection of carbohydrates: qualitative and quantitative analysis.

PubMed

Bibi, Aisha; Ju, Huangxian

2016-04-01

A quantum dots (QDs) assisted laser desorption/ionization mass spectrometric (QDA-LDI-MS) strategy was proposed for qualitative and quantitative analysis of a series of carbohydrates. The adsorption of carbohydrates on the modified surface of different QDs as the matrices depended mainly on the formation of hydrogen bonding, which led to higher MS intensity than those with conventional organic matrix. The effects of QDs concentration and sample preparation method were explored for improving the selective ionization process and the detection sensitivity. The proposed approach offered a new dimension to the application of QDs as matrices for MALDI-MS research of carbohydrates. It could be used for quantitative measurement of glucose concentration in human serum with good performance. The QDs served as a matrix showed the advantages of low background, higher sensitivity, convenient sample preparation and excellent stability under vacuum. The QDs assisted LDI-MS approach has promising application to the analysis of carbohydrates in complex biological samples. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of optimal biomass pretreatment strategies for biofuel production: investigation of relationships between surface-exposed polysaccharides and their enzymatic conversion using carbohydrate-binding modules.

PubMed

Khatri, Vinay; Meddeb-Mouelhi, Fatma; Adjallé, Kokou; Barnabé, Simon; Beauregard, Marc

2018-01-01

Pretreatment of lignocellulosic biomass (LCB) is a key step for its efficient bioconversion into ethanol. Determining the best pretreatment and its parameters requires monitoring its impacts on the biomass material. Here, we used fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay to study the relationship between surface-exposed polysaccharides and enzymatic hydrolysis of LCB. Our results indicated that alkali extrusion pretreatment led to the highest hydrolysis rates for alfalfa stover, cattail stems and flax shives, despite its lower lignin removal efficiency compared to alkali pretreatment. Corn crop residues were more sensitive to alkali pretreatments, leading to higher hydrolysis rates. A clear relationship was consistently observed between total surface-exposed cellulose detected by the FTCM-depletion assay and biomass enzymatic hydrolysis. Comparison of bioconversion yield and total composition analysis (by NREL/TP-510-42618) of LCB prior to or after pretreatments did not show any close relationship. Lignin removal efficiency and total cellulose content (by NREL/TP-510-42618) led to an unreliable prediction of enzymatic polysaccharide hydrolysis. Fluorescent protein-tagged carbohydrate-binding modules method (FTCM)-depletion assay provided direct evidence that cellulose exposure is the key determinant of hydrolysis yield. The clear and robust relationships that were observed between the cellulose accessibility by FTCM probes and enzymatic hydrolysis rates change could be evolved into a powerful prediction tool that might help develop optimal biomass pretreatment strategies for biofuel production.

Peroxisomal biogenesis is genetically and biochemically linked to carbohydrate metabolism in Drosophila and mouse

PubMed Central

Chao, Yu-Hsin; Giagtzoglou, Nikolaos; Putluri, Nagireddy; Coarfa, Cristian; Donti, Taraka; Faust, Joseph E.; McNew, James A.; Sardiello, Marco; Baes, Myriam; Bellen, Hugo J.

2017-01-01

Peroxisome biogenesis disorders (PBD) are a group of multi-system human diseases due to mutations in the PEX genes that are responsible for peroxisome assembly and function. These disorders lead to global defects in peroxisomal function and result in severe brain, liver, bone and kidney disease. In order to study their pathogenesis we undertook a systematic genetic and biochemical study of Drosophila pex16 and pex2 mutants. These mutants are short-lived with defects in locomotion and activity. Moreover these mutants exhibit severe morphologic and functional peroxisomal defects. Using metabolomics we uncovered defects in multiple biochemical pathways including defects outside the canonical specialized lipid pathways performed by peroxisomal enzymes. These included unanticipated changes in metabolites in glycolysis, glycogen metabolism, and the pentose phosphate pathway, carbohydrate metabolic pathways that do not utilize known peroxisomal enzymes. In addition, mutant flies are starvation sensitive and are very sensitive to glucose deprivation exhibiting dramatic shortening of lifespan and hyperactivity on low-sugar food. We use bioinformatic transcriptional profiling to examine gene co-regulation between peroxisomal genes and other metabolic pathways and we observe that the expression of peroxisomal and carbohydrate pathway genes in flies and mouse are tightly correlated. Indeed key steps in carbohydrate metabolism were found to be strongly co-regulated with peroxisomal genes in flies and mice. Moreover mice lacking peroxisomes exhibit defective carbohydrate metabolism at the same key steps in carbohydrate breakdown. Our data indicate an unexpected link between these two metabolic processes and suggest metabolism of carbohydrates could be a new therapeutic target for patients with PBD. PMID:28640802

Association between Carbohydrate Intake and Serum Lipids

PubMed Central

Ma, Yunsheng; Chiriboga, David E.; Olendzki, Barbara C.; Li, Wenjun; Leung, Katherine; Hafner, Andrea R.; Li, Youfu; Ockene, Ira S.; Hebert, James R.

2006-01-01

Background The effect of dietary carbohydrate on blood lipids has received considerable attention in light of the current trend in lowering carbohydrate intake for weight loss. Objectives To evaluate the association between carbohydrate intake and serum lipids. Methods Blood samples and 24-hour dietary and physical activity recall interviews were obtained from each subject at quarterly intervals for five consecutive quarters between 1994 and 1998 from 574 healthy adults in Central Massachusetts. Relationships between serum lipids and dietary carbohydrate factors were assessed using linear mixed models and adjusting for other risk factors known to be related to blood lipids. Both cross-sectional and longitudinal results were reported. Results Cross-sectional analysis results from this study suggest that higher total carbohydrate intake, percentage of calories from carbohydrate, glycemic index (GI) and/or glycemic load (GL) are related to lower high-density lipoprotein cholesterol (HDL-C) and higher serum triacylglycerol levels, while higher total carbohydrate intake and/or GL are related to lower total and low-density lipoprotein cholesterol (LDL-C) levels. In a one-year longitudinal analysis, GL was positively associated with total and LDL-C levels, and there was an inverse association between percentage of calories from carbohydrate and HDL-C levels. Conclusions Results suggest that there is a complex and predominantly unfavorable effect of increased intake of highly processed carbohydrate on lipid profile, which may have implications for metabolic syndrome, diabetes, and coronary heart disease. Further studies in the form of randomized controlled trials are required to investigate these associations and determine the implications for lipid management. PMID:16582033

[Carbohydrate metabolism in children with pulmonary tuberculosis].

PubMed

Tadzhidinova, M G; Aksenova, V A; Fateev, I I; Sevost'ianova, T A; Makinskiĭ, A I

1998-01-01

Examining carbohydrate metabolism in 59 children with pulmonary tuberculosis ascertained that to get tuberculosis naturally resulted in lower tissue sensitivity to insulin and in hyperinsulinemia. Effective treatment of children improves carbohydrate metabolism. However, there is no normalization of carbohydrate metabolism even in clinical cure.

Vacuum ultraviolet photoionization of carbohydrates and nucleotides

NASA Astrophysics Data System (ADS)

Shin, Joong-Won; Bernstein, Elliot R.

2014-01-01

Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5'-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

Vacuum ultraviolet photoionization of carbohydrates and nucleotides.

PubMed

Shin, Joong-Won; Bernstein, Elliot R

2014-01-28

Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5(')-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate, rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C-C and C-O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.

Vacuum ultraviolet photoionization of carbohydrates and nucleotides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, Joong-Won, E-mail: jshin@govst.edu; Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872; Bernstein, Elliot R., E-mail: erb@lamar.colostate.edu

Carbohydrates (2-deoxyribose, ribose, and xylose) and nucleotides (adenosine-, cytidine-, guanosine-, and uridine-5{sup ′}-monophosphate) are generated in the gas phase, and ionized with vacuum ultraviolet photons (VUV, 118.2 nm). The observed time of flight mass spectra of the carbohydrate fragmentation are similar to those observed [J.-W. Shin, F. Dong, M. Grisham, J. J. Rocca, and E. R. Bernstein, Chem. Phys. Lett. 506, 161 (2011)] for 46.9 nm photon ionization, but with more intensity in higher mass fragment ions. The tendency of carbohydrate ions to fragment extensively following ionization seemingly suggests that nucleic acids might undergo radiation damage as a result of carbohydrate,more » rather than nucleobase fragmentation. VUV photoionization of nucleotides (monophosphate-carbohydrate-nucleobase), however, shows that the carbohydrate-nucleobase bond is the primary fragmentation site for these species. Density functional theory (DFT) calculations indicate that the removed carbohydrate electrons by the 118.2 nm photons are associated with endocyclic C–C and C–O ring centered orbitals: loss of electron density in the ring bonds of the nascent ion can thus account for the observed fragmentation patterns following carbohydrate ionization. DFT calculations also indicate that electrons removed from nucleotides under these same conditions are associated with orbitals involved with the nucleobase-saccharide linkage electron density. The calculations give a general mechanism and explanation of the experimental results.« less

[Diet and civilization diseases--carbohydrate aspects].

PubMed

Haslbeck, M

1990-01-01

Carbohydrates are a major component of our food, they are important as body energy stores and they play an important role in cellular structures. In the present paper a classification of food carbohydrates, of dietary fibers and sweeteners is presented and the major physiological effects are discussed. Furthermore, the significance of carbohydrates for the etiology and the treatment of nutrition related diseases which are closely related to the development of arteriosclerosis is outlined. Carbohydrates are beside fat the major determinants of the daily caloric intake. This illustrates their impact on the development of obesity with its predominant role as a risk factor for the development of cardiovascular disease. Furthermore, the role of sugar consumption in the relation to dental caries is stressed. Also the central role of carbohydrate consumption for the treatment of diabetes mellitus is described. Problems of the diabetes diet, the role of the dietary fiber in the treatment of different diseases and the necessity of sweetness in nutrition are discussed in greater detail.

Carbohydrate-Binding Non-Peptidic Pradimicins for the Treatment of Acute Sleeping Sickness in Murine Models.

PubMed

Castillo-Acosta, Víctor M; Ruiz-Pérez, Luis M; Etxebarria, Juan; Reichardt, Niels C; Navarro, Miguel; Igarashi, Yasuhiro; Liekens, Sandra; Balzarini, Jan; González-Pacanowska, Dolores

2016-09-01

Current treatments available for African sleeping sickness or human African trypanosomiasis (HAT) are limited, with poor efficacy and unacceptable safety profiles. Here, we report a new approach to address treatment of this disease based on the use of compounds that bind to parasite surface glycans leading to rapid killing of trypanosomes. Pradimicin and its derivatives are non-peptidic carbohydrate-binding agents that adhere to the carbohydrate moiety of the parasite surface glycoproteins inducing parasite lysis in vitro. Notably, pradimicin S has good pharmaceutical properties and enables cure of an acute form of the disease in mice. By inducing resistance in vitro we have established that the composition of the sugars attached to the variant surface glycoproteins are critical to the mode of action of pradimicins and play an important role in infectivity. The compounds identified represent a novel approach to develop drugs to treat HAT.

Carbohydrate-Binding Non-Peptidic Pradimicins for the Treatment of Acute Sleeping Sickness in Murine Models

PubMed Central

Castillo-Acosta, Víctor M.; Ruiz-Pérez, Luis M.; Reichardt, Niels C.; Igarashi, Yasuhiro; Liekens, Sandra; Balzarini, Jan

2016-01-01

Current treatments available for African sleeping sickness or human African trypanosomiasis (HAT) are limited, with poor efficacy and unacceptable safety profiles. Here, we report a new approach to address treatment of this disease based on the use of compounds that bind to parasite surface glycans leading to rapid killing of trypanosomes. Pradimicin and its derivatives are non-peptidic carbohydrate-binding agents that adhere to the carbohydrate moiety of the parasite surface glycoproteins inducing parasite lysis in vitro. Notably, pradimicin S has good pharmaceutical properties and enables cure of an acute form of the disease in mice. By inducing resistance in vitro we have established that the composition of the sugars attached to the variant surface glycoproteins are critical to the mode of action of pradimicins and play an important role in infectivity. The compounds identified represent a novel approach to develop drugs to treat HAT. PMID:27662652

Decarbonylation and dehydrogenation of carbohydrates

DOEpatents

Andrews, Mark A.; Klaeren, Stephen A.

1991-01-01

Carbohydrates, especially aldose or ketose sugars, including those whose carbonyl group is masked by hemi-acetal or hemi-ketal formation, are decarbonylated by heating the feed carbohydrate together with a transition metal complex in a suitable solvent. Also, primary alcohols, including sugar alditols are simultaneously dehydrogenated and decarbonylated by heating a mixture of rhodium and ruthenium complexes and the alcohol and optionally a hydrogen acceptor in an acceptable solvent. Such defarbonylation and/or dehydrogenation of sugars provides a convenient procedure for the synthesis of certain carbohydrates and may provide a means for the conversion of biomass into useful products.

Fructose-maltodextrin ratio in a carbohydrate-electrolyte solution differentially affects exogenous carbohydrate oxidation rate, gut comfort, and performance.

PubMed

O'Brien, Wendy J; Rowlands, David S

2011-01-01

Solutions containing multiple carbohydrates utilizing different intestinal transporters (glucose and fructose) show enhanced absorption, oxidation, and performance compared with single-carbohydrate solutions, but the impact of the ratio of these carbohydrates on outcomes is unknown. In a randomized double-blind crossover, 10 cyclists rode 150 min at 50% peak power, then performed an incremental test to exhaustion, while ingesting artificially sweetened water or one of three carbohydrate-salt solutions comprising fructose and maltodextrin in the respective following concentrations: 4.5 and 9% (0.5-Ratio), 6 and 7.5% (0.8-Ratio), and 7.5 and 6% (1.25-Ratio). The carbohydrates were ingested at 1.8 g/min and naturally (13)C-enriched to permit evaluation of oxidation rate by mass spectrometry and indirect calorimetry. Mean exogenous carbohydrate oxidation rates were 1.04, 1.14, and 1.05 g/min (coefficient of variation 20%) in 0.5-, 0.8-, and 1.25-Ratios, respectively, representing likely small increases in 0.8-Ratio of 11% (90% confidence limits; ± 4%) and 10% (± 4%) relative to 0.5- and 1.25-Ratios, respectively. Comparisons of fat and total and endogenous carbohydrate oxidation rates between solutions were unclear. Relative to 0.5-Ratio, there were moderate improvements to peak power with 0.8- (3.6%; 99% confidence limits ± 3.5%) and 1.25-Ratio (3.0%; ± 3.7%) but unclear with water (0.4%; ± 4.4%). Increases in stomach fullness, abdominal cramping, and nausea were lowest with the 0.8- followed by the 1.25-Ratio solution. At high carbohydrate-ingestion rate, greater benefits to endurance performance may result from ingestion of 0.8- to 1.25-Ratio fructose-maltodextrin solutions. Small perceptible improvements in gut comfort favor the 0.8-Ratio and provide a clearer suggestion of mechanism than the relationship with exogenous carbohydrate oxidation.

Carbohydrates as indicators of biogeochemical processes

NASA Astrophysics Data System (ADS)

Lazareva, E. V.; Romankevich, E. A.

2012-05-01

A method is presented to study the carbohydrate composition of marine objects involved into sedimento- and diagenesis (plankton, particulate matter, benthos, and bottom sediments). The analysis of the carbohydrates is based upon the consecutive separation of their fractions with different solvents (water, alkali, and acid). The ratio of the carbohydrate fractions allows one to evaluate the lability of the carbohydrate complex. It is also usable as an indicator of the biogeochemical processes in the ocean, as well of the genesis and the degree of conversion of organic matter in the bottom sediments and nodules. The similarity in the monosaccharide composition is shown for dissolved organic matter and aqueous and alkaline fractions of seston and particulate matter.

Near Surface Swimming of Salmonella Typhimurium Explains Target-Site Selection and Cooperative Invasion

PubMed Central

Kreibich, Saskia; Vonaesch, Pascale; Andritschke, Daniel; Rout, Samuel; Weidner, Kerstin; Sormaz, Milos; Songhet, Pascal; Horvath, Peter; Chabria, Mamta; Vogel, Viola; Spori, Doris M.; Jenny, Patrick; Hardt, Wolf-Dietrich

2012-01-01

Targeting of permissive entry sites is crucial for bacterial infection. The targeting mechanisms are incompletely understood. We have analyzed target-site selection by S. Typhimurium. This enteropathogenic bacterium employs adhesins (e.g. fim) and the type III secretion system 1 (TTSS-1) for host cell binding, the triggering of ruffles and invasion. Typically, S. Typhimurium invasion is focused on a subset of cells and multiple bacteria invade via the same ruffle. It has remained unclear how this is achieved. We have studied target-site selection in tissue culture by time lapse microscopy, movement pattern analysis and modeling. Flagellar motility (but not chemotaxis) was required for reaching the host cell surface in vitro. Subsequently, physical forces trapped the pathogen for ∼1.5–3 s in “near surface swimming”. This increased the local pathogen density and facilitated “scanning” of the host surface topology. We observed transient TTSS-1 and fim-independent “stopping” and irreversible TTSS-1-mediated docking, in particular at sites of prominent topology, i.e. the base of rounded-up cells and membrane ruffles. Our data indicate that target site selection and the cooperative infection of membrane ruffles are attributable to near surface swimming. This mechanism might be of general importance for understanding infection by flagellated bacteria. PMID:22911370

Dietary carbohydrates and glucose metabolism in diabetic patients.

PubMed

Parillo, M; Riccardi, G

1995-12-01

Dietary carbohydrates represent one of the major sources of energy for the human body. However, the main (if not the only) therapy for diabetes since ancient times has been based on reducing dietary carbohydrates drastically because of their effects on blood glucose levels. The introduction of insulin in the 1920s and then of oral hypoglycaemic drugs led to various studies evaluating the biochemical characteristics of carbohydrates and their effects on glucose metabolism in diabetic patients. This review considers the role of dietary carbohydrates in the diet of diabetic patients in the light of the most recent studies and provides a short summary of the biochemistry of carbohydrates and the physiology of carbohydrate digestion.

Effect of structural modifications of ganglioside GM2 on intra-molecular carbohydrate-to-carbohydrate interaction and enzymatic susceptibility

PubMed Central

Li, Yu-Teh; Li, Su-Chen; Kiso, Makoto; Ishida, Hideharu; Mauri, Laura; Raimondi, Laura; Bernardi, Anna; Sonnino, Sandro

2008-01-01

Summary The effect of inter-molecular carbohydrate-to-carbohydrate interaction on basic cell biological processes has been well documented and appreciated. In contrast, very little is known about the intra-molecular carbohydrate-to-carbohydrate interaction. The presence of an interaction between the GalNAc and the Neu5Ac in GM2 detected by NMR spectroscopy represents a well-defined intra-molecular carbohydrate-to-carbohydrate interaction. This intriguing interaction is responsible for the GM2-epitope, GalNAcβ1Π4(Neu5Acα2Π3)Gal-, to exhibit a rigid and compact conformation. We hypothesized that this compact conformation may be the cause for both the GalNAc and the Neu5Ac in GM2 to be refractory to enzymatic hydrolysis and the GM2 activator protein is able to interact with the compact trisaccharide GM2-epitope, rendering the GalNAc and the Neu5Ac accessible to β-hexosaminidase A and sialidase. We have used a series of structurally modified GM2 to study the effect of modifications of sugar chains on the conformation and enzymatic susceptibility of this ganglioside. Our hypothesis was borne out by the fact that when the GalNAcβ1Π4Gal linkage in GM2 was converted to the GalNAcβ1Π6Gal, both the GalNAc and the Neu5Ac became susceptible to β-hexosaminidase A and sialidase, respectively, without GM2 activator protein. We hope our work will engender interest in identifying other intra-molecular carbohydrate-to-carbohydrate interactions in glycoconjugates. PMID:17967427

Effect of structural modifications of ganglioside GM2 on intra-molecular carbohydrate-to-carbohydrate interaction and enzymatic susceptibility.

PubMed

Li, Yu-Teh; Li, Su-Chen; Kiso, Makoto; Ishida, Hideharu; Mauri, Laura; Raimondi, Laura; Bernardi, Anna; Sonnino, Sandro

2008-03-01

The effect of inter-molecular carbohydrate-to-carbohydrate interaction on basic cell biological processes has been well documented and appreciated. In contrast, very little is known about the intra-molecular carbohydrate-to-carbohydrate interaction. The presence of an interaction between the GalNAc and the Neu5Ac in GM2 detected by NMR spectroscopy represents a well-defined intra-molecular carbohydrate-to-carbohydrate interaction. This intriguing interaction is responsible for the GM2-epitope, GalNAcbeta1-->4(Neu5Acalpha2-->3)Gal-, to exhibit a rigid and compact conformation. We hypothesized that this compact conformation may be the cause for both the GalNAc and the Neu5Ac in GM2 to be refractory to enzymatic hydrolysis and the GM2 activator protein is able to interact with the compact trisaccharide GM2-epitope, rendering the GalNAc and the Neu5Ac accessible to beta-hexosaminidase A and sialidase. We have used a series of structurally modified GM2 to study the effect of modifications of sugar chains on the conformation and enzymatic susceptibility of this ganglioside. Our hypothesis was borne out by the fact that when the GalNAcbeta1-->4Gal linkage in GM2 was converted to the GalNAcbeta1-->6Gal, both the GalNAc and the Neu5Ac became susceptible to beta-hexosaminidase A and sialidase, respectively, without GM2 activator protein. We hope our work will engender interest in identifying other intra-molecular carbohydrate-to-carbohydrate interactions in glycoconjugates.

The role of dietary carbohydrates in organismal aging.

PubMed

Lee, Dongyeop; Son, Heehwa G; Jung, Yoonji; Lee, Seung-Jae V

2017-05-01

Carbohydrates are essential nutrients that are used as a primary source of energy. Carbohydrate utilization should be properly controlled, as abnormal regulation of carbohydrate metabolism is associated with diseases, such as diabetes, cardiovascular diseases, and stroke. These metabolic syndromes have become a serious problem in developed countries, and there is an increased need for research examining the influence of carbohydrates on animal physiology. Diets enriched in glucose, a major carbohydrate, are also associated with accelerated aging in several model organisms, including yeast and Caenorhabditis elegans (C. elegans). Genetic factors that mediate the effects of high glucose diets on aging have been identified during the last decade, mostly through the use of C. elegans. In this review, we describe studies that determine the effects of carbohydrate-enriched diets on aging by focusing on the mechanisms through which evolutionarily conserved pathways mediate the lifespan-altering effects of glucose in C. elegans. These include the insulin/insulin-like growth factor-1, sterol-regulatory element-binding protein, and AMP-activated protein kinase signaling pathways. We also discuss the effects of various carbohydrates and carbohydrate-derived metabolites on aging in model organisms and cultured mammalian cells. Finally, we discuss how dietary carbohydrates influence health and aging in humans.

Identification of distant drug off-targets by direct superposition of binding pocket surfaces.

PubMed

Schumann, Marcel; Armen, Roger S

2013-01-01

Correctly predicting off-targets for a given molecular structure, which would have the ability to bind a large range of ligands, is both particularly difficult and important if they share no significant sequence or fold similarity with the respective molecular target ("distant off-targets"). A novel approach for identification of off-targets by direct superposition of protein binding pocket surfaces is presented and applied to a set of well-studied and highly relevant drug targets, including representative kinases and nuclear hormone receptors. The entire Protein Data Bank is searched for similar binding pockets and convincing distant off-target candidates were identified that share no significant sequence or fold similarity with the respective target structure. These putative target off-target pairs are further supported by the existence of compounds that bind strongly to both with high topological similarity, and in some cases, literature examples of individual compounds that bind to both. Also, our results clearly show that it is possible for binding pockets to exhibit a striking surface similarity, while the respective off-target shares neither significant sequence nor significant fold similarity with the respective molecular target ("distant off-target").

A Central Role of Abscisic Acid in Stress-Regulated Carbohydrate Metabolism

PubMed Central

Kempa, Stefan; Krasensky, Julia; Dal Santo, Silvia; Kopka, Joachim; Jonak, Claudia

2008-01-01

Background Abiotic stresses adversely affect plant growth and development. The hormone abscisic acid (ABA) plays a central role in the response and adaptation to environmental constraints. However, apart from the well established role of ABA in regulating gene expression programmes, little is known about its function in plant stress metabolism. Principal Findings Using an integrative multiparallel approach of metabolome and transcriptome analyses, we studied the dynamic response of the model glyophyte Arabidopsis thaliana to ABA and high salt conditions. Our work shows that salt stress induces complex re-adjustment of carbohydrate metabolism and that ABA triggers the initial steps of carbon mobilisation. Significance These findings open new perspectives on how high salinity and ABA impact on central carbohydrate metabolism and highlight the power of iterative combinatorial approaches of non-targeted and hypothesis-driven experiments in stress biology. PMID:19081841

Potential effect of ultrasound on carbohydrates.

PubMed

Bera, Smritilekha; Mondal, Dhananjoy; Martin, Jacob T; Singh, Man

2015-06-17

The use of ultrasound has emerged as one of the most useful alternative energy sources for the synthesis of carbohydrate-derived biologically and pharmaceutically potential compounds. Spectacular advances have been made in the field of sonication-assisted organic reactions, which are known for producing superior yields, enhanced reactivity of the reactant, improved stereoselectivity, and shortened reaction times. Orthogonal protection-deprotection reactions and/or modification and manipulation of functional groups in carbohydrates are common synthetic steps in carbohydrate chemistry. These reaction steps can be driven by the ultrasonic energy generated by acoustic cavitation via the formation and subsequent collapse of ultrasound-induced bubbles. The ultrasound-assisted synthesis of differently functionalised monosaccharides is useful in a wide variety of applications of carbohydrate chemistry such as the glycosylation of oligosaccharides, one pot domino reactions, thioglycoside syntheses, azidoglycoside syntheses, 1,3-dipolar cycloaddition reactions, and syntheses of natural products. This review article covers ultrasound-mediated reactions on carbohydrates that have been described in the literature since 2000. Copyright © 2015 Elsevier Ltd. All rights reserved.

Regulation of low-density lipoprotein subfractions by carbohydrates.

PubMed

Gerber, Philipp A; Berneis, Kaspar

2012-07-01

This article aims at reviewing the recent findings that have been made concerning the crosstalk of carbohydrate metabolism with the generation of small, dense low-density lipoprotein (LDL) particles, which are known to be associated with an adverse cardiovascular risk profile. Studies conducted during the past few years have quite unanimously shown that the quantity of carbohydrates ingested is associated with a decrease of LDL particle size and an increase in its density. Conversely, diets that aim at a reduction of carbohydrate intake are able to improve LDL quality. Furthermore, a reduction of the glycaemic index without changing the amount of carbohydrates ingested has similar effects. Diseases with altered carbohydrate metabolism, for example, type 2 diabetes, are associated with small, dense LDL particles. Finally, even the kind of monosaccharide the carbohydrate intake consists of is important concerning LDL particle size: fructose has been shown to alter the LDL particle subclass profile more adversely than glucose in many recent studies. LDL particle quality, rather than its quantity, is affected by carbohydrate metabolism, which is of clinical importance, in particular, in the light of increased carbohydrate consumption in today's world.

Effects of surface displayed targeting ligand GE11 on liposome distribution and extravasation in tumor.

PubMed

Tang, Hailing; Chen, Xiaojing; Rui, Mengjie; Sun, Wenqiang; Chen, Jian; Peng, Jinliang; Xu, Yuhong

2014-10-06

Targeting ligands displayed on liposome surface had been used to mediate specific interactions and drug delivery to target cells. However, they also affect liposome distribution in vivo, as well as the tissue extravasation processes after IV injection. In this study, we incorporated an EGFR targeting peptide GE11 on liposome surfaces in addition to PEG at different densities and evaluated their targeting properties and antitumor effects. We found that the densities of surface ligand and PEG were critical to target cell binding in vitro as well as pharmacokinetic profiles in vivo. The inclusion of GE11-PEG-DSPE and PEG-DSPE at 2% and 4% mol ratios in the liposome formulation mediated a rapid accumulation of liposomes within 1 h after IV injection in the tumor tissues surrounding neovascular structures. This is in addition to the EPR effect that was most prominently described for surface PEG modified liposomes. Therefore, despite the fact that the distribution of liposomes into interior tumor tissues was still limited by diffusion, GE11 targeted doxorubicin loaded liposomes showed significantly better antitumor activity in tumor bearing mice as a result of the fast active-targeting efficiency. We anticipate these understandings can benefit further optimization of targeted drug delivery systems for improving efficacy in vivo.

Aminooxylated Carbohydrates: Synthesis and Applications.

PubMed

Pifferi, Carlo; Daskhan, Gour Chand; Fiore, Michele; Shiao, Tze Chieh; Roy, René; Renaudet, Olivier

2017-08-09

Among other classes of biomolecules, carbohydrates and glycoconjugates are widely involved in numerous biological functions. In addition to addressing the related synthetic challenges, glycochemists have invested intense efforts in providing access to structures that can be used to study, activate, or inhibit these biological processes. Over the past few decades, aminooxylated carbohydrates have been found to be key building blocks for achieving these goals. This review provides the first in-depth overview covering several aspects related to the syntheses and applications of aminooxylated carbohydrates. After a brief introduction to oxime bonds and their relative stabilities compared to related C═N functions, synthetic aspects of oxime ligation and methodologies for introducing the aminooxy functionality onto both glycofuranosyls and glycopyranosyls are described. The subsequent section focuses on biological applications involving aminooxylated carbohydrates as components for the construcion of diverse architectures. Mimetics of natural structures represent useful tools for better understanding the features that drive carbohydrate-receptor interaction, their biological output and they also represent interesting structures with improved stability and tunable properties. In the next section, multivalent structures such as glycoclusters and glycodendrimers obtained through oxime ligation are described in terms of synthetic design and their biological applications such as immunomodulators. The second-to-last section discusses miscellaneous applications of oxime-based glycoconjugates, such as enantioselective catalysis and glycosylated oligonucleotides, and conclusions and perspectives are provided in the last section.

Stereochemical Control in Carbohydrate Chemistry

ERIC Educational Resources Information Center

Batchelor, Rhys; Northcote, Peter T.; Harvey, Joanne E.; Dangerfield, Emma M.; Stocker, Bridget L.

2008-01-01

Carbohydrates, in the form of glycoconjugates, have recently been shown to control a wide range of cellular processes. Accordingly, students interested in the study of organic chemistry and biomedical sciences should be exposed to carbohydrate chemistry. To this end, we have developed a sequence of experiments that leads the student from the…

Structural Basis for Carbohydrate Recognition and Anti-inflammatory Modulation by Gastrointestinal Nematode Parasite Toxascaris leonina Galectin*

PubMed Central

Hwang, Eun Young; Jeong, Mi Suk; Park, Sang Kyun; Ha, Sung Chul; Yu, Hak Sun; Jang, Se Bok

2016-01-01

Toxascaris leonina galectin (Tl-gal) is a galectin-9 homologue protein isolated from an adult worm of the canine gastrointestinal nematode parasite, and Tl-gal-vaccinated challenge can inhibit inflammation in inflammatory bowel disease-induced mice. We determined the first X-ray structures of full-length Tl-gal complexes with carbohydrates (lactose, N-acetyllactosamine, lacto-N-tetraose, sialyllactose, and glucose). Bonds were formed on concave surfaces of both carbohydrate recognition domains (CRDs) in Tl-gal. All binding sites were found in the HXXXR and WGXEER motifs. Charged Arg61/Arg196 and Glu80/Glu215 on the conserved motif of Tl-gal N-terminal CRD and C-terminal CRD are critical amino acids for recognizing carbohydrate binding, and the residues can affect protein folding and structure. The polar amino acids His, Asn, and Trp are also important residues for the interaction with carbohydrates through hydrogen bonding. Hemagglutination activities of Tl-gal were inhibited by interactions with carbohydrates and mutations. We found that the mutation of Tl-gal (E80A/E215A) at the carbohydrate binding region induced protein aggregation and could be caused in many diseases. The short linker region between the N-terminal and C-terminal CRDs of Tl-gal was very stable against proteolysis and maintained its biological activity. This structural information is expected to elucidate the carbohydrate recognition mechanism of Tl-gal and improve our understanding of anti-inflammatory mediators and modulators of immune response. PMID:27742836

Identification of Distant Drug Off-Targets by Direct Superposition of Binding Pocket Surfaces

PubMed Central

Schumann, Marcel; Armen, Roger S.

2013-01-01

Correctly predicting off-targets for a given molecular structure, which would have the ability to bind a large range of ligands, is both particularly difficult and important if they share no significant sequence or fold similarity with the respective molecular target (“distant off-targets”). A novel approach for identification of off-targets by direct superposition of protein binding pocket surfaces is presented and applied to a set of well-studied and highly relevant drug targets, including representative kinases and nuclear hormone receptors. The entire Protein Data Bank is searched for similar binding pockets and convincing distant off-target candidates were identified that share no significant sequence or fold similarity with the respective target structure. These putative target off-target pairs are further supported by the existence of compounds that bind strongly to both with high topological similarity, and in some cases, literature examples of individual compounds that bind to both. Also, our results clearly show that it is possible for binding pockets to exhibit a striking surface similarity, while the respective off-target shares neither significant sequence nor significant fold similarity with the respective molecular target (“distant off-target”). PMID:24391782

Carbohydrate Counting

MedlinePlus

... help you manage your blood glucose. It sounds complex, but with time you and your diabetes care team can figure out the right balance for you. How Much Carbohydrate? A great place to start may be to ...

Alteration of the carbohydrate-binding specificity of a C-type lectin CEL-I mutant with an EPN carbohydrate-binding motif.

PubMed

Hatakeyama, Tomomitsu; Ishimine, Tomohiro; Baba, Tomohiro; Kimura, Masanari; Unno, Hideaki; Goda, Shuichiro

2013-07-01

CEL-I is a Gal/GalNAc-specific C-type lectin isolated from the sea cucumber Cucumaria echinata. This lectin is composed of two carbohydrate-recognition domains (CRDs) with the carbohydrate-recognition motif QPD (Gln-Pro- Asp), which is generally known to exist in galactose-specific C-type CRDs. In the present study, a mutant CEL-I with EPN (Glu-Pro-Asn) motif, which is thought to be responsible for the carbohydrate-recognition of mannose-specific Ctype CRDs, was produced in Escherichia coli, and its effects on the carbohydrate-binding specificity were examined using polyamidoamine dendrimer (PD) conjugated with carbohydrates. Although wild-type CEL-I effectively formed complexes with N-acetylgalactosamine (GalNAc)-PD but not with mannose-PD, the mutant CEL-I showed relatively weak but definite affinity for mannose-PD. These results indicated that the QPD and EPN motifs play a significant role in the carbohydrate-recognition mechanism of CEL-I, especially in the discrimination of galactose and mannose. Additional mutations in the recombinant CEL-I binding site may further increase its specificity for mannose, and should provide insights into designing novel carbohydrate-recognition proteins.

Thin film surface treatments for lowering dust adhesion on Mars Rover calibration targets

NASA Astrophysics Data System (ADS)

Sabri, F.; Werhner, T.; Hoskins, J.; Schuerger, A. C.; Hobbs, A. M.; Barreto, J. A.; Britt, D.; Duran, R. A.

The current generation of calibration targets on Mars Rover serve as a color and radiometric reference for the panoramic camera. They consist of a transparent silicon-based polymer tinted with either color or grey-scale pigments and cast with a microscopically rough Lambertian surface for a diffuse reflectance pattern. This material has successfully withstood the harsh conditions existent on Mars. However, the inherent roughness of the Lambertian surface (relative to the particle size of the Martian airborne dust) and the tackiness of the polymer in the calibration targets has led to a serious dust accumulation problem. In this work, non-invasive thin film technology was successfully implemented in the design of future generation calibration targets leading to significant reduction of dust adhesion and capture. The new design consists of a μm-thick interfacial layer capped with a nm-thick optically transparent layer of pure metal. The combination of these two additional layers is effective in burying the relatively rough Lambertian surface while maintaining diffuse properties of the samples which is central to the correct operation as calibration targets. A set of these targets are scheduled for flight on the Mars Phoenix mission.

A comparison of low-carbohydrate vs. high-carbohydrate diets: energy restriction, nutrient quality and correlation to body mass index.

PubMed

Bowman, Shanthy A; Spence, Joseph T

2002-06-01

To evaluate free-living adults' diets that ranged from very low to high amounts of carbohydrate for their energy content, nutritional quality and correlation to Body Mass Index. Adults ages 19 years and older, who had complete dietary intake data on day-1 of the USDA's 1994 to 1996 Continuing Survey of Food Intakes by Individuals (CSFII 1994-1996), were divided into four groups--very low, low, moderate and high carbohydrate--based on the percent total energy from carbohydrate. Mean energy, nutrient, food intakes and Body Mass Index values were compared among the groups. SUDAAN software package was used for the data analysis and pair-wise mean comparisons (p < 0.05). The high-carbohydrate diet was lower in energy and energy density (number of kilocalories per gram of total amount of food consumed) than the other three diets. Macronutrient composition varied significantly among all the four groups. Nutrient density (amount of nutrient per 1,000 kilocalories of energy consumed) of vitamin A, carotene, vitamin C, folate, calcium, magnesium and iron increased and that of vitamin B12 and zinc decreased with an increase in the percent total energy from carbohydrate. The high-carbohydrate group ate more of low-fat foods, grain products and fruits. This group also had the lowest sodium intake. Adults eating a high-carbohydrate diet are more likely to have Body Mass Index values below 25. A study of diets of free-living adults in the U.S. showed that diets high in carbohydrate were both energy restrictive and nutritious and may be adopted for successful weight management.

One-pot multienzyme (OPME) systems for chemoenzymatic synthesis of carbohydrates.

PubMed

Yu, Hai; Chen, Xi

2016-03-14

Glycosyltransferase-catalyzed enzymatic and chemoenzymatic syntheses are powerful approaches for the production of oligosaccharides, polysaccharides, glycoconjugates, and their derivatives. Enzymes involved in the biosynthesis of sugar nucleotide donors can be combined with glycosyltransferases in one pot for efficient production of the target glycans from simple monosaccharides and acceptors. The identification of enzymes involved in the salvage pathway of sugar nucleotide generation has greatly facilitated the development of simplified and efficient one-pot multienzyme (OPME) systems for synthesizing major glycan epitopes in mammalian glycomes. The applications of OPME methods are steadily gaining popularity mainly due to the increasing availability of wild-type and engineered enzymes. Substrate promiscuity of these enzymes and their mutants allows OPME synthesis of carbohydrates with naturally occurring post-glycosylational modifications (PGMs) and their non-natural derivatives using modified monosaccharides as precursors. The OPME systems can be applied in sequence for synthesizing complex carbohydrates. The sequence of the sequential OPME processes, the glycosyltransferase used, and the substrate specificities of the glycosyltransferases define the structures of the products. The OPME and sequential OPME strategies can be extended to diverse glycans in other glycomes when suitable enzymes with substrate promiscuity become available. This Perspective summarizes the work of the authors and collaborators on the development of glycosyltransferase-based OPME systems for carbohydrate synthesis. Future directions are also discussed.

One-pot multienzyme (OPME) systems for chemoenzymatic synthesis of carbohydrates

PubMed Central

Yu, Hai; Chen, Xi

2016-01-01

Glycosyltransferase-catalyzed enzymatic and chemoenzymatic syntheses are powerful approaches for the production of oligosaccharides, polysaccharides, glycoconjugates, and their derivatives. Enzymes involved in the biosynthesis of sugar nucleotide donors can be combined with the glycosyltransferases in one pot for efficient production of target glycans from simple monosaccharides and accpetors. The identification of enzymes involved in the salvage pathway of sugar nucleotide generation has greatly facilitate the development of simplified and efficient one-pot multienzyme (OPME) systems for synthesizing major glycan epitopes in mammalian glycomes. The applications of OPME methods are steadily gaining popularity mainly due to the increasing availability of wild-type and engineered enzymes. Substrate promiscuity of these enzymes and their mutants allows OPME synthesis of carbohydrates with naturally occurring post-glycosylational modificiation (PGMs) and their non-natural derivatives using modified monosaccharides as precursors. The OPME systems can be applied in sequential for synthesizing complex carbohydrates. The sequence of the sequential OPME processes, the glycosyltransferase used, and the substrate specificities of glycosyltransferasese define the structures of the products. The OPME and sequential OPME strategies can be extended to diverse glycans in other glycomes when suitable enzymes with substrate promiscuity become available. The Perspective summariezes the work of the authors and collaborators on the development of glycosyltransferase-based OPME systems for carbohydrate synthesis. Future directions are also discussed. PMID:26881499

Application of Biocatalysis to on-DNA Carbohydrate Library Synthesis.

PubMed

Thomas, Baptiste; Lu, Xiaojie; Birmingham, William R; Huang, Kun; Both, Peter; Reyes Martinez, Juana Elizabeth; Young, Robert J; Davie, Christopher P; Flitsch, Sabine L

2017-05-04

DNA-encoded libraries are increasingly used for the discovery of bioactive lead compounds in high-throughput screening programs against specific biological targets. Although a number of libraries are now available, they cover limited chemical space due to bias in ease of synthesis and the lack of chemical reactions that are compatible with DNA tagging. For example, compound libraries rarely contain complex biomolecules such as carbohydrates with high levels of functionality, stereochemistry, and hydrophilicity. By using biocatalysis in combination with chemical methods, we aimed to significantly expand chemical space and generate generic libraries with potentially better biocompatibility. For DNA-encoded libraries, biocatalysis is particularly advantageous, as it is highly selective and can be performed in aqueous environments, which is an essential feature for this split-and-mix library technology. In this work, we demonstrated the application of biocatalysis for the on-DNA synthesis of carbohydrate-based libraries by using enzymatic oxidation and glycosylation in combination with traditional organic chemistry. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Multiple Carbohydrate Binding Specificities of Helicobacter pylori

NASA Astrophysics Data System (ADS)

Teneberg, Susann

Persistent colonization of the human stomach by Helicobacter pylori is a risk factor for the development of peptic ulcer disease and gastric cancer. Adhesion of microbes to the target tissue is an important determinant for successful initiation, establishment and maintenance of infection, and a variety of different candidate carbohydrate receptors for H. pylori have been identified. Here the different the binding specifities, and their potential role in adhesion to human gastric epithelium are described. Finally, recent findings on the roles of sialic acid binding SabA adhesin in interactions with human neutrophils and erythrocytes are discussed.

Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity.

PubMed

Warda, Alicja K; Siezen, Roland J; Boekhorst, Jos; Wells-Bennik, Marjon H J; de Jong, Anne; Kuipers, Oscar P; Nierop Groot, Masja N; Abee, Tjakko

2016-01-01

We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed.

A Review of the “Bolus Guide,” A New Insulin Bolus Dosing Support Tool Based on Selection of Carbohydrate Ranges

PubMed Central

Pańkowska, Ewa

2010-01-01

In this issue of Journal of Diabetes Science and Technology, Shapira and colleagues present new concepts of carbohydrate load estimation in intensive insulin therapy. By using a mathematical model, they attempt to establish how accurately carbohydrate food content should be maintained in order to keep postprandial blood glucose levels in the recommended range. Their mathematical formula, the “bolus guide” (BG), is verified by simulating prandial insulin dosing and responding to proper blood glucose levels. Different variants such as insulin sensitivity factor, insulin-to-carbohydrate ratio, and target blood glucose were taken into this formula in establishing the calculated proper insulin dose. The new approach presented here estimates the carbohydrate content by rearranging the carbohydrate load instead of the simple point estimation that the current bolus calculators (BCs) use. Computerized estimations show that the BG directives, as compared to a BC, result in more glucose levels above 200 mg/dl and thus indicate less hypoglycemia readings. PMID:20663454

Randomized controlled trial of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates on body weight and blood lipids: the CARMEN study. The Carbohydrate Ratio Management in European National diets.

PubMed

Saris, W H; Astrup, A; Prentice, A M; Zunft, H J; Formiguera, X; Verboeket-van de Venne, W P; Raben, A; Poppitt, S D; Seppelt, B; Johnston, S; Vasilaras, T H; Keogh, G F

2000-10-01

To investigate the long-term effects of changes in dietary carbohydrate/fat ratio and simple vs complex carbohydrates. Randomized controlled multicentre trial (CARMEN), in which subjects were allocated for 6 months either to a seasonal control group (no intervention) or to one of three experimental groups: a control diet group (dietary intervention typical of the average national intake); a low-fat high simple carbohydrate group; or a low-fat high complex carbohydrate group. Three hundred and ninety eight moderately obese adults. The change in body weight was the primary outcome; changes in body composition and blood lipids were secondary outcomes. Body weight loss in the low-fat high simple carbohydrate and low-fat high complex carbohydrate groups was 0.9 kg (P < 0.05) and 1.8 kg (P < 0.001), while the control diet and seasonal control groups gained weight (0.8 and 0.1 kg, NS). Fat mass changed by -1.3kg (P< 0.01), -1.8kg (P< 0.001) and +0.6kg (NS) in the low-fat high simple carbohydrate, low-fat high complex carbohydrate and control diet groups, respectively. Changes in blood lipids did not differ significantly between the dietary treatment groups. Our findings suggest that reduction of fat intake results in a modest but significant reduction in body weight and body fatness. The concomitant increase in either simple or complex carbohydrates did not indicate significant differences in weight change. No adverse effects on blood lipids were observed. These findings underline the importance of this dietary change and its potential impact on the public health implications of obesity.

Improved Procedure for Direct Coupling of Carbohydrates to Proteins via Reductive Amination

PubMed Central

Gildersleeve, Jeffrey C.; Oyelaran, Oyindasola; Simpson, John T.; Allred, Benjamin

2009-01-01

Carbohydrate-protein conjugates are utilized extensively in basic research and as immunogens in a variety of bacterial vaccines and cancer vaccines. As a result, there have been significant efforts to develop simple and reliable methods for the construction of these conjugates. While direct coupling via reductive amination is an appealing approach, the reaction is typically very inefficient. In this paper, we report improved reaction conditions providing an approximately 500% increase in yield. In addition to optimizing a series of standard reaction parameters, we found that addition of 500 mM sodium sulfate improves the coupling efficiency. To illustrate the utility of these conditions, a series of high mannose BSA conjugates were produced and incorporated into a carbohydrate microarray. Ligand binding to ConA could be observed and apparent affinity constants (Kds) measured using the array were in good agreement with values reported by surface plasmon resonance. The results show that the conditions are suitable for microgram scale reactions, are compatible with complex carbohydrates, and produce biologically active conjugates. PMID:18597509

Ion beam sputtering of fluoropolymers. [etching polymer films and target surfaces

NASA Technical Reports Server (NTRS)

Sovey, J. S.

1978-01-01

Ion beam sputter processing rates as well as pertinent characteristics of etched targets and films are described. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Sputter target and film characteristics documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs are included.

Renal function following long-term weight loss in individuals with abdominal obesity on a very-low-carbohydrate diet vs high-carbohydrate diet.

PubMed

Brinkworth, Grant D; Buckley, Jonathan D; Noakes, Manny; Clifton, Peter M

2010-04-01

A frequently cited concern of very-low-carbohydrate diets is the potential for increased risk of renal disease associated with a higher protein intake. However, to date, no well-controlled randomized studies have evaluated the long-term effects of very-low-carbohydrate diets on renal function. To study this issue, renal function was assessed in 68 men and women with abdominal obesity (age 51.5+/-7.7 years, body mass index [calculated as kg/m(2)] 33.6+/-4.0) without preexisting renal dysfunction who were randomized to consume either an energy-restricted ( approximately 1,433 to 1,672 kcal/day), planned isocaloric very-low-carbohydrate (4% total energy as carbohydrate [14 g], 35% protein [124 g], 61% fat [99 g]), or high-carbohydrate diet (46% total energy as carbohydrate [162 g], 24% protein [85 g], 30% fat [49 g]) for 1 year. Body weight, serum creatinine, estimated glomerular filtration rate and urinary albumin excretion were assessed before and after 1 year (April 2006-July 2007). Repeated measures analysis of variance was conducted. Weight loss was similar in both groups (very-low-carbohydrate: -14.5+/-9.7 kg, high-carbohydrate: -11.6+/-7.3 kg; P=0.16). By 1 year, there were no changes in either group in serum creatinine levels (very-low-carbohydrate: 72.4+/-15.1 to 71.3+/-13.8 mumol/L, high-carbohydrate: 78.0+/-16.0 to 77.2+/-13.2 mumol/L; P=0.93 time x diet effect) or estimated glomerular filtration rate (very-low-carbohydrate: 90.0+/-17.0 to 91.2+/-17.8 mL/min/1.73 m(2), high-carbohydrate: 83.8+/-13.8 to 83.6+/-11.8 mL/min/1.73 m(2); P=0.53 time x diet effect). All but one participant was classified as having normoalbuminuria at baseline, and for these participants, urinary albumin excretion values remained in the normoalbuminuria range at 1 year. One participant in high-carbohydrate had microalbuminuria (41.8 microg/min) at baseline, which decreased to a value of 3.1 microg/min (classified as normoalbuminuria) at 1 year. This study provides preliminary

Carbohydrate Nutrition and Team Sport Performance.

PubMed

Williams, Clyde; Rollo, Ian

2015-11-01

The common pattern of play in 'team sports' is 'stop and go', i.e. where players perform repeated bouts of brief high-intensity exercise punctuated by lower intensity activity. Sprints are generally 2-4 s long and recovery between sprints is of variable length. Energy production during brief sprints is derived from the degradation of intra-muscular phosphocreatine and glycogen (anaerobic metabolism). Prolonged periods of multiple sprints drain muscle glycogen stores, leading to a decrease in power output and a reduction in general work rate during training and competition. The impact of dietary carbohydrate interventions on team sport performance have been typically assessed using intermittent variable-speed shuttle running over a distance of 20 m. This method has evolved to include specific work to rest ratios and skills specific to team sports such as soccer, rugby and basketball. Increasing liver and muscle carbohydrate stores before sports helps delay the onset of fatigue during prolonged intermittent variable-speed running. Carbohydrate intake during exercise, typically ingested as carbohydrate-electrolyte solutions, is also associated with improved performance. The mechanisms responsible are likely to be the availability of carbohydrate as a substrate for central and peripheral functions. Variable-speed running in hot environments is limited by the degree of hyperthermia before muscle glycogen availability becomes a significant contributor to the onset of fatigue. Finally, ingesting carbohydrate immediately after training and competition will rapidly recover liver and muscle glycogen stores.

Neurobiologic basis of craving for carbohydrates.

PubMed

Ventura, Tamara; Santander, Jaime; Torres, Rafael; Contreras, Ana María

2014-03-01

There is a relationship between emotional disorders, obesity, and craving for carbohydrates. This relationship complicates the success of treatments aimed at combatting obesity, which is considered to be the epidemic of the twenty-first century. We conducted a review of the neurobiologic basis for carbohydrate craving, with the hope that this understanding will enable the design of more efficient therapeutic strategies. We conducted a non-systematic literature search in PubMed using MeSH. Research on the basis of carbohydrate craving is varied, but may be grouped into five main areas: the serotonergic system, palatability and hedonic response, the motivational system, stress response systems, and gene-environment interaction. The models that integrate motivational systems with palatability and hedonic response studies are the ones that we believe can best explain both craving for carbohydrates and related addictive phenomena. Research has contributed to a greater understanding of the neurobiologic basis of carbohydrate craving. The latter, in turn, contributes to an understanding of the implications, challenges, and possible therapies that might be put in place to cope with this phenomenon. Copyright © 2014 Elsevier Inc. All rights reserved.

Carbohydrate-based vaccine adjuvants - discovery and development.

PubMed

Hu, Jing; Qiu, Liying; Wang, Xiaoli; Zou, Xiaopeng; Lu, Mengji; Yin, Jian

2015-10-01

The addition of a suitable adjuvant to a vaccine can generate significant effective adaptive immune responses. There is an urgent need for the development of novel po7tent and safe adjuvants for human vaccines. Carbohydrate molecules are promising adjuvants for human vaccines due to their high biocompatibility and good tolerability in vivo. The present review covers a few promising carbohydrate-based adjuvants, lipopolysaccharide, trehalose-6,6'-dibehenate, QS-21 and inulin as examples, which have been extensively studied in human vaccines in a number of preclinical and clinical studies. The authors discuss the current status, applications and strategies of development of each adjuvant and different adjuvant formulation systems. This information gives insight regarding the exciting prospect in the field of carbohydrate-based adjuvant research. Carbohydrate-based adjuvants are promising candidates as an alternative to the Alum salts for human vaccines development. Furthermore, combining two or more adjuvants in one formulation is one of the effective strategies in adjuvant development. However, further research efforts are needed to study and develop novel adjuvants systems, which can be more stable, potent and safe. The development of synthetic carbohydrate chemistry can improve the study of carbohydrate-based adjuvants.

Healthy carbohydrates

USDA-ARS?s Scientific Manuscript database

Functional foods include dietary fiber consisting of health-promoting carbohydrates. We have produced novel prebiotics from orange peel and observed that they extend the shelf life of probiotic bacteria in synbiotics. Some pectic-oligosaccharides and xyloglucan-oligosaccharides also have anti-adhesi...

Treatment of ovarian cancer by targeting the tumor stem cell-associated carbohydrate antigen, Sialyl-Thomsen-nouveau.

PubMed

Starbuck, Kristen; Al-Alem, Linah; Eavarone, David A; Hernandez, Silvia Fatima; Bellio, Chiara; Prendergast, Jillian M; Stein, Jenna; Dransfield, Daniel T; Zarrella, Bianca; Growdon, Whitfield B; Behrens, Jeff; Foster, Rosemary; Rueda, Bo R

2018-05-01

Recurrent ovarian cancer (OvCa) is thought to result in part from the inability to eliminate rare quiescent cancer stem cells (CSCs) that survive cytotoxic chemotherapy and drive tumor resurgence. The Sialyl-Thomsen-nouveau antigen (STn) is a carbohydrate moiety present on protein markers of CSCs in pancreatic, colon, and gastric malignancies. We have demonstrated that human OvCa cell lines contain varying levels of cells that independently express either STn or the ovarian CSC marker CD133. Here we determine co-expression of STn and CD133 in a subset of human OvCa cell lines. Analyses of colony and sphere forming capacity and of response to standard-of-care cytotoxic therapy suggest a subset of OvCa STn + cells display some CSC features. The effect of the anti-STn antibody-drug conjugates (ADCs) S3F-CL-MMAE and 2G12-2B2-CL-MMAE on OvCa cell viability in vitro and in vivo was also assessed. Treatment with S3F-CL-MMAE reduced the viability of two of three OvCa cell lines in vitro and exposure to either S3F-CL-MMAE or 2G12-2B2-CL-MMAE reduced OVCAR3-derived xenograft volume in vivo , depleting STn + tumor cells. In summary, STn + cells demonstrate some stem-like properties and specific therapeutic targeting of STn in ovarian tumors may be an effective clinical strategy to eliminate both STn + CSC and STn + non-CSC populations.

Carbohydrate Polymers for Nonviral Nucleic Acid Delivery

PubMed Central

Sizovs, Antons; McLendon, Patrick M.; Srinivasachari, Sathya

2014-01-01

Carbohydrates have been investigated and developed as delivery vehicles for shuttling nucleic acids into cells. In this review, we present the state of the art in carbohydrate-based polymeric vehicles for nucleic acid delivery, with the focus on the recent successes in preclinical models, both in vitro and in vivo. Polymeric scaffolds based on the natural polysaccharides chitosan, hyaluronan, pullulan, dextran, and schizophyllan each have unique properties and potential for modification, and these results are discussed with the focus on facile synthetic routes and favorable performance in biological systems. Many of these carbohydrates have been used to develop alternative types of biomaterials for nucleic acid delivery to typical polyplexes, and these novel materials are discussed. Also presented are polymeric vehicles that incorporate copolymerized carbohydrates into polymer backbones based on polyethylenimine and polylysine and their effect on transfection and biocompatibility. Unique scaffolds, such as clusters and polymers based on cyclodextrin (CD), are also discussed, with the focus on recent successes in vivo and in the clinic. These results are presented with the emphasis on the role of carbohydrate and charge on transfection. Use of carbohydrates as molecular recognition ligands for cell-type specific delivery is also briefly reviewed. We contend that carbohydrates have contributed significantly to progress in the field of non-viral DNA delivery, and these new discoveries are impactful for developing new vehicles and materials for treatment of human disease. PMID:21504102

Regulation of carbohydrate metabolism and flight performance by a hypertrehalosaemic hormone in the mosquito Anopheles gambiae

PubMed Central

Kaufmann, Christian; Brown, Mark R.

2008-01-01

The role of adipokinetic hormones (AKHs) in the regulation of carbohydrate and lipid metabolism and flight performance was evaluated for females of the African malaria mosquito, Anopheles gambiae. Injection of various dosages of synthetic Anoga-AKH-I increased carbohydrate levels in the haemolymph and reduced glycogen reserves in sugar-fed females but did not affect lipid levels. Anoga-AKH-I enhanced the flight performance of both intact and decapitated sugar-fed females, during a 4 hour flight period. Anoga-AKH-II had no effect on carbohydrate or lipid levels or flight performance, thus its function remains unknown. Targeted RNA-interference lowered Anoga-AKH receptor expression in sugar-fed females, consequently injections of Anoga-AKH-I failed to mobilize glycogen reserves. Taken together, these results show that a primary role for the neurohormone, Anoga-AKH-I, is to elevate trehalose levels in the haemolymph of female mosquitoes. PMID:18062987

Linking Bacillus cereus Genotypes and Carbohydrate Utilization Capacity

PubMed Central

Warda, Alicja K.; Siezen, Roland J.; Boekhorst, Jos; Wells-Bennik, Marjon H. J.; de Jong, Anne; Kuipers, Oscar P.; Nierop Groot, Masja N.; Abee, Tjakko

2016-01-01

We characterised carbohydrate utilisation of 20 newly sequenced Bacillus cereus strains isolated from food products and food processing environments and two laboratory strains, B. cereus ATCC 10987 and B. cereus ATCC 14579. Subsequently, genome sequences of these strains were analysed together with 11 additional B. cereus reference genomes to provide an overview of the different types of carbohydrate transporters and utilization systems found in B. cereus strains. The combined application of API tests, defined growth media experiments and comparative genomics enabled us to link the carbohydrate utilisation capacity of 22 B. cereus strains with their genome content and in some cases to the panC phylogenetic grouping. A core set of carbohydrates including glucose, fructose, maltose, trehalose, N-acetyl-glucosamine, and ribose could be used by all strains, whereas utilisation of other carbohydrates like xylose, galactose, and lactose, and typical host-derived carbohydrates such as fucose, mannose, N-acetyl-galactosamine and inositol is limited to a subset of strains. Finally, the roles of selected carbohydrate transporters and utilisation systems in specific niches such as soil, foods and the human host are discussed. PMID:27272929

Association of late-night carbohydrate intake with glucose tolerance among pregnant African American women.

PubMed

Chandler-Laney, Paula C; Schneider, Camille R; Gower, Barbara A; Granger, Wesley M; Mancuso, Melissa S; Biggio, Joseph R

2016-10-01

Obesity and late-night food consumption are associated with impaired glucose tolerance. Late-night carbohydrate consumption may be particularly detrimental during late pregnancy because insulin sensitivity declines as pregnancy progresses. Further, women who were obese (Ob) prior to pregnancy have lower insulin sensitivity than do women of normal weight (NW). The aim of this study is to test the hypothesis that night-time carbohydrate consumption is associated with poorer glucose tolerance in late pregnancy and that this association would be exacerbated among Ob women. Forty non-diabetic African American women were recruited based upon early pregnancy body mass index (NW, <25 kg m(-2) ; Ob, ≥30 kg m(-2) ). Third trimester free-living dietary intake was assessed by food diary, and indices of glucose tolerance and insulin action were assessed during a 75-g oral glucose tolerance test. Women in the Ob group reported greater average 24-h energy intake (3055 kcal vs. 2415 kcal, P < 0.05). Across the whole cohort, night-time, but not day-time, carbohydrate intake was positively associated with glucose concentrations after the glucose load and inversely associated with early phase insulin secretion (P < 0.05). Multiple linear regression modelling within each weight group showed that the associations among late-night carbohydrate intake, glucose concentrations and insulin secretion were present only in the Ob group. This is the first study to report an association of night-time carbohydrate intake specifically on glucose tolerance and insulin action during pregnancy. If replicated, these results suggest that late-night carbohydrate intake may be a potential target for intervention to improve metabolic health of Ob women in late pregnancy. © 2015 John Wiley & Sons Ltd.

Carbohydrates, pollinators, and cycads

PubMed Central

Marler, Thomas E; Lindström, Anders J

2015-01-01

Cycad biology, ecology, and horticulture decisions are not supported by adequate research, and experiments in cycad physiology in particular have been deficient. Our recent report on free sugar content in a range of cycad taxa and tissues sets the stage for developing continued carbohydrate research. Growth and development of cycad pollen, mediation of the herbivory traits of specialist pollinators, and support of expensive strobilus behavioral traits are areas of cycad pollination biology that would benefit from a greater understanding of the role of carbohydrate relations. PMID:26479502

Structural Basis for Carbohydrate Recognition and Anti-inflammatory Modulation by Gastrointestinal Nematode Parasite Toxascaris leonina Galectin.

PubMed

Hwang, Eun Young; Jeong, Mi Suk; Park, Sang Kyun; Ha, Sung Chul; Yu, Hak Sun; Jang, Se Bok

2016-12-02

Toxascaris leonina galectin (Tl-gal) is a galectin-9 homologue protein isolated from an adult worm of the canine gastrointestinal nematode parasite, and Tl-gal-vaccinated challenge can inhibit inflammation in inflammatory bowel disease-induced mice. We determined the first X-ray structures of full-length Tl-gal complexes with carbohydrates (lactose, N-acetyllactosamine, lacto-N-tetraose, sialyllactose, and glucose). Bonds were formed on concave surfaces of both carbohydrate recognition domains (CRDs) in Tl-gal. All binding sites were found in the HXXXR and WGXEER motifs. Charged Arg 61 /Arg 196 and Glu 80 /Glu 215 on the conserved motif of Tl-gal N-terminal CRD and C-terminal CRD are critical amino acids for recognizing carbohydrate binding, and the residues can affect protein folding and structure. The polar amino acids His, Asn, and Trp are also important residues for the interaction with carbohydrates through hydrogen bonding. Hemagglutination activities of Tl-gal were inhibited by interactions with carbohydrates and mutations. We found that the mutation of Tl-gal (E80A/E215A) at the carbohydrate binding region induced protein aggregation and could be caused in many diseases. The short linker region between the N-terminal and C-terminal CRDs of Tl-gal was very stable against proteolysis and maintained its biological activity. This structural information is expected to elucidate the carbohydrate recognition mechanism of Tl-gal and improve our understanding of anti-inflammatory mediators and modulators of immune response. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Wood adhesives containing proteins and carbohydrates

USDA-ARS?s Scientific Manuscript database

In recent years there has been resurgent interest in using biopolymers as sustainable and environmentally friendly ingredients in wood adhesive formulations. Among them, proteins and carbohydrates are the most commonly used. In this chapter, an overview is given of protein-based and carbohydrate-...

An underwater ranging system based on photoacoustic effect occurring on target surface

NASA Astrophysics Data System (ADS)

Ni, Kai; Hu, Kai; Li, Xinghui; Wang, Lidai; Zhou, Qian; Wang, Xiaohao

2016-11-01

In this paper, an underwater ranging system based on photoacoustic effect occurring on target surface is proposed. In this proposal, laser pulse generated by blue-green laser is directly incident on target surface, where the photoacoustic effect occurs and a sound source is formed. And then the sound wave which is also called photoacoustic signal is received by the ultrasonic receiver after passing through water. According to the time delay between transmitting laser and receiving photoacoustic signal, and sound velocity in water, the distance between the target and the ultrasonic receiver can be calculated. Differing from underwater range finding by only laser, this approach can avoid backscattering of laser beam, so easier to implement. Experimental system according to this principle has been constructed to verify the feasibility of this technology. The experimental results showed that a ranging accuracy of 1 mm can be effectively achieved when the target is close to the ultrasonic receiver.

Improving carbohydrate production of Chlorella sorokiniana NIES-2168 through semi-continuous process coupled with mixotrophic cultivation.

PubMed

Wang, Yue; Chiu, Sheng-Yi; Ho, Shih-Hsin; Liu, Zhuo; Hasunuma, Tomohisa; Chang, Ting-Ting; Chang, Kuan-Fu; Chang, Jo-Shu; Ren, Nan-Qi; Kondo, Akihiko

2016-08-01

Biofuels from microalgae is now a hot issue of great potential. However, achieving high starch productivity with photoautotrophic microalgae is still challenging. A feasible approach to enhance the growth and target product of microalgae is to conduct mixotrophic cultivation. The appropriate acetate addition combined with CO2 supply as dual carbon sources (i.e., mixotrophic cultivation) could enhance the cell growth of some microalgae species, but the effect of acetate-mediated mixotrophic culture mode on carbohydrate accumulation in microalgae remains unclear. Moreover, there is still lack of the information concerning how to increase the productivity of carbohydrates from microalgae under acetate-amended mixotrophic cultivation and how to optimize the engineering strategies to achieve the goal. This study was undertaken to develop an optimal acetate-contained mixotrophic cultivation system coupled with effective operation strategies to markedly improve the carbohydrate productivity of Chlorella sorokiniana NIES-2168. The optimal carbohydrate productivity of 695 mg/L/d was obtained, which is the highest value ever reported. The monosaccharide in the accumulated carbohydrates is mainly glucose (i.e., 85-90%), which is very suitable for bio-alcohols fermentation. Hence, by applying the optimal process developed in this study, C. sorokiniana NIES-2168 has a high potential to serve as a feedstock for subsequent biofuels conversion. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Three-dimensional potential energy surface of selected carbohydrates' CH/π dispersion interactions calculated by high-level quantum mechanical methods.

PubMed

Kozmon, Stanislav; Matuška, Radek; Spiwok, Vojtěch; Koča, Jaroslav

2011-05-09

In this study we present the first systematic computational three-dimensional scan of carbohydrate hydrophobic patches for the ability to interact through CH/π dispersion interactions. The carbohydrates β-d-glucopyranose, β-d-mannopyranose and α-l-fucopyranose were studied in a complex with a benzene molecule, which served as a model of the CH/π interaction in carbohydrate/protein complexes. The 3D relaxed scans were performed at the SCC-DFTB-D level with 3 757 grid points for both carbohydrate hydrophobic sides. The interaction energy of all grid points was recalculated at the DFT-D BP/def2-TZVPP level. The results obtained clearly show highly delimited and separated areas around each CH group, with an interaction energy up to -5.40 kcal mol(-1) . The results also show that with increasing H⋅⋅⋅π distance these delimited areas merge and form one larger region, which covers all hydrogen atoms on that specific carbohydrate side. Simultaneously, the interaction becomes weaker with an energy of -2.5 kcal mol(-1) . All local energy minima were optimized at the DFT-D BP/def2-TZVPP level and the interaction energies of these complexes were refined by use of the high-level ab initio computation at the CCSD(T)/CBS level. Results obtained from the optimization suggest that the CH group hydrogen atoms are not equivalent and the interaction energy at the CCSD(T)/CBS level range from -3.54 to -5.40 kcal mol(-1) . These results also reveal that the optimal H⋅⋅⋅π distance for the CH/π dispersion interaction is approximately (2.310±0.030) Å, and the angle defined as carbon-hydrogen-benzene geometrical centre is (180±30)°. These results reveal that whereas the dispersion interactions with the lowest interaction energies are quite strictly located in space, the slightly higher interaction energy regions adopt a much larger space. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The long underestimated carbonyl function of carbohydrates – an organocatalyzed shot into carbohydrate chemistry.

PubMed

Mahrwald, R

2015-09-21

The aggressive and strong development of organocatalysis provides several protocols for the convenient utilization of the carbonyl function of unprotected carbohydrates in C-C-bond formation processes. These amine-catalyzed mechanisms enable multiple cascade-protocols for the synthesis of a wide range of carbohydrate-derived compound classes. Several, only slightly different protocols, have been developed for the application of 1,3-dicarbonyl compounds in the stereoselective chain-elongation of unprotected carbohydrates and the synthesis of highly functionalized C-glycosides of defined configuration. In addition, C-glycosides can also be accessed by amine-catalyzed reactions with methyl ketones. By a one-pot cascade reaction of isocyanides with unprotected aldoses and amino acids access to defined configured glycopeptide mimetics is achieved. Depending on the reaction conditions different origins to control the installation of configuration during the bond-formation process were observed.

Significant suppression of myocardial (18)F-fluorodeoxyglucose uptake using 24-h carbohydrate restriction and a low-carbohydrate, high-fat diet.

PubMed

Kobayashi, Yasuhiro; Kumita, Shin-ichiro; Fukushima, Yoshimitsu; Ishihara, Keiichi; Suda, Masaya; Sakurai, Minoru

2013-11-01

(18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) is a useful tool for evaluating inflammation. Because, myocardial-FDG uptake occurs with diverse physiology, it should be suppressed during evaluation of myocardial inflammation by FDG-PET/CT. Diets inducing fat-based metabolism, such as a low-carbohydrate, high-fat diet (LCHF), are used in uptake-suppression protocols. However, a complete suppression of myocardial-FDG uptake has not been established. Hence, we assessed the efficacy of 24-h carbohydrate restriction along with an LCHF diet compared to that of the conventional protocol in suppressing myocardial-FDG uptake and also compared fat and glucose metabolism between these protocols. Fourteen healthy volunteers agreed to undergo >24-h carbohydrate restriction (glucose, <10g) and drank an LCHF beverage an hour before FDG administration. A scan performed under conventional fasting protocol served as the control. The maximal standardized uptake values (SUVmax) of the left ventricular (LV) myocardium, and left atrium lumen (blood pool), liver, and lung fields as background, were measured. Blood sugar, free fatty acids (FFAs), insulin, and triglyceride concentrations were measured just before FDG injection and compared between the 2 protocols. Global LV myocardial uptake was significantly lower with the diet-preparation protocol (SUVmax 1.31 [1.15-1.49] vs. 2.98 [1.76-6.43], p=0.001). Target-to-background ratios [myocardium-to-blood ratio (MBR), myocardium-to-lung ratio (MLR), and myocardium-to-liver ratio (MLvR)] were also significantly lower with the diet-preparation protocol [MBR: 0.75 (0.68-0.84) vs. 1.63 (0.98-4.09), p<0.001; MLR: 1.87 (1.53-2.47) vs. 4.54 (2.53-12.78), p=0.004; MLvR: 0.48 (0.44-0.56) vs. 1.11 (0.63-2.32), p=0.002]. Only insulin levels were significantly different between the subjects in each protocol group (11.3 [6.2-15.1] vs. 3.9 [2.9-6.2]). Carbohydrate restriction together with an LCHF supplement

Structural motif screening reveals a novel, conserved carbohydrate-binding surface in the pathogenesis-related protein PR-5d.

PubMed

Doxey, Andrew C; Cheng, Zhenyu; Moffatt, Barbara A; McConkey, Brendan J

2010-08-03

Aromatic amino acids play a critical role in protein-glycan interactions. Clusters of surface aromatic residues and their features may therefore be useful in distinguishing glycan-binding sites as well as predicting novel glycan-binding proteins. In this work, a structural bioinformatics approach was used to screen the Protein Data Bank (PDB) for coplanar aromatic motifs similar to those found in known glycan-binding proteins. The proteins identified in the screen were significantly associated with carbohydrate-related functions according to gene ontology (GO) enrichment analysis, and predicted motifs were found frequently within novel folds and glycan-binding sites not included in the training set. In addition to numerous binding sites predicted in structural genomics proteins of unknown function, one novel prediction was a surface motif (W34/W36/W192) in the tobacco pathogenesis-related protein, PR-5d. Phylogenetic analysis revealed that the surface motif is exclusive to a subfamily of PR-5 proteins from the Solanaceae family of plants, and is absent completely in more distant homologs. To confirm PR-5d's insoluble-polysaccharide binding activity, a cellulose-pulldown assay of tobacco proteins was performed and PR-5d was identified in the cellulose-binding fraction by mass spectrometry. Based on the combined results, we propose that the putative binding site in PR-5d may be an evolutionary adaptation of Solanaceae plants including potato, tomato, and tobacco, towards defense against cellulose-containing pathogens such as species of the deadly oomycete genus, Phytophthora. More generally, the results demonstrate that coplanar aromatic clusters on protein surfaces are a structural signature of glycan-binding proteins, and can be used to computationally predict novel glycan-binding proteins from 3 D structure.

A step towards personalized sports nutrition: carbohydrate intake during exercise.

PubMed

Jeukendrup, Asker

2014-05-01

There have been significant changes in the understanding of the role of carbohydrates during endurance exercise in recent years, which allows for more specific and more personalized advice with regard to carbohydrate ingestion during exercise. The new proposed guidelines take into account the duration (and intensity) of exercise and advice is not restricted to the amount of carbohydrate; it also gives direction with respect to the type of carbohydrate. Studies have shown that during exercise lasting approximately 1 h in duration, a mouth rinse or small amounts of carbohydrate can result in a performance benefit. A single carbohydrate source can be oxidized at rates up to approximately 60 g/h and this is the recommendation for exercise that is more prolonged (2-3 h). For ultra-endurance events, the recommendation is higher at approximately 90 g/h. Carbohydrate ingested at such high ingestion rates must be a multiple transportable carbohydrates to allow high oxidation rates and prevent the accumulation of carbohydrate in the intestine. The source of the carbohydrate may be a liquid, semisolid, or solid, and the recommendations may need to be adjusted downward when the absolute exercise intensity is low and thus carbohydrate oxidation rates are also low. Carbohydrate intake advice is independent of body weight as well as training status. Therefore, although these guidelines apply to most athletes, they are highly dependent on the type and duration of activity. These new guidelines may replace the generic existing guidelines for carbohydrate intake during endurance exercise.

Association of carbohydrate and fat intake with metabolic syndrome.

PubMed

Kwon, Yu-Jin; Lee, Hye-Sun; Lee, Ji-Won

2018-04-01

In Asia, dietary pattern has been changed with increased intake of refined carbohydrates, sugar, and saturated fat, while the prevalence of metabolic syndrome (MetS) is on the rise. However, it remains unclear whether a high-carbohydrate or a high-fat diet is more metabolically harmful, and the optimal amount of carbohydrates and fat has not been determined. The aim of our study was to examine the role of carbohydrate and fat intake in MetS in a Korean population. Data were obtained from a large, population-based, cross-sectional study (6737 males and 8845 females). The subjects were divided into nine groups based on carbohydrate and fat proportion, and multiple logistic regression analysis was performed after adjusting for confounding variables. Regardless of fat intake, the risk of MetS significantly increased in males with higher carbohydrate proportions (of total energy intake). In females, the risk of MetS was significantly elevated only in those with both the highest carbohydrate proportion and lowest fat proportion. A high carbohydrate proportion was associated with a higher prevalence of MetS in males, and a high carbohydrate proportion combined with a low fat proportion was associated with MetS in females. Our results indicate that reduction of excessive carbohydrate intake paired with an adequate fat intake, taking into consideration optimal types of fat, is useful for MetS prevention. Longitudinal studies are needed to clarify the optimal types and amounts of carbohydrate and fat proportions as well as the mechanism underlying these relationships. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Plant Lectins Targeting O-Glycans at the Cell Surface as Tools for Cancer Diagnosis, Prognosis and Therapy.

PubMed

Poiroux, Guillaume; Barre, Annick; van Damme, Els J M; Benoist, Hervé; Rougé, Pierre

2017-06-09

Aberrant O -glycans expressed at the surface of cancer cells consist of membrane-tethered glycoproteins (T and Tn antigens) and glycolipids (Lewis a, Lewis x and Forssman antigens). All of these O -glycans have been identified as glyco-markers of interest for the diagnosis and the prognosis of cancer diseases. These epitopes are specifically detected using T/Tn-specific lectins isolated from various plants such as jacalin from Artocarpus integrifola , and fungi such as the Agaricus bisporus lectin. These lectins accommodate T/Tn antigens at the monosaccharide-binding site; residues located in the surrounding extended binding-site of the lectins often participate in the binding of more extended epitopes. Depending on the shape and size of the extended carbohydrate-binding site, their fine sugar-binding specificity towards complex O -glycans readily differs from one lectin to another, resulting in a great diversity in their sugar-recognition capacity. T/Tn-specific lectins have been extensively used for the histochemical detection of cancer cells in biopsies and for the follow up of the cancer progression and evolution. T/Tn-specific lectins also induce a caspase-dependent apoptosis in cancer cells, often associated with a more or less severe inhibition of proliferation. Moreover, they provide another potential source of molecules adapted to the building of photosensitizer-conjugates allowing a specific targeting to cancer cells, for the photodynamic treatment of tumors.

Plant Lectins Targeting O-Glycans at the Cell Surface as Tools for Cancer Diagnosis, Prognosis and Therapy

PubMed Central

Poiroux, Guillaume; Barre, Annick; van Damme, Els J. M.; Benoist, Hervé; Rougé, Pierre

2017-01-01

Aberrant O-glycans expressed at the surface of cancer cells consist of membrane-tethered glycoproteins (T and Tn antigens) and glycolipids (Lewis a, Lewis x and Forssman antigens). All of these O-glycans have been identified as glyco-markers of interest for the diagnosis and the prognosis of cancer diseases. These epitopes are specifically detected using T/Tn-specific lectins isolated from various plants such as jacalin from Artocarpus integrifola, and fungi such as the Agaricus bisporus lectin. These lectins accommodate T/Tn antigens at the monosaccharide-binding site; residues located in the surrounding extended binding-site of the lectins often participate in the binding of more extended epitopes. Depending on the shape and size of the extended carbohydrate-binding site, their fine sugar-binding specificity towards complex O-glycans readily differs from one lectin to another, resulting in a great diversity in their sugar-recognition capacity. T/Tn-specific lectins have been extensively used for the histochemical detection of cancer cells in biopsies and for the follow up of the cancer progression and evolution. T/Tn-specific lectins also induce a caspase-dependent apoptosis in cancer cells, often associated with a more or less severe inhibition of proliferation. Moreover, they provide another potential source of molecules adapted to the building of photosensitizer-conjugates allowing a specific targeting to cancer cells, for the photodynamic treatment of tumors. PMID:28598369

Carbohydrate regulation of photosynthesis and respiration from branch girdling in four species of wet tropical rain forest trees.

PubMed

Asao, Shinichi; Ryan, Michael G

2015-06-01

How trees sense source-sink carbon balance remains unclear. One potential mechanism is a feedback from non-structural carbohydrates regulating photosynthesis and removing excess as waste respiration when the balance of photosynthesis against growth and metabolic activity changes. We tested this carbohydrate regulation of photosynthesis and respiration using branch girdling in four tree species in a wet tropical rainforest in Costa Rica. Because girdling severs phloem to stop carbohydrate export while leaving xylem intact to allow photosynthesis, we expected carbohydrates to accumulate in leaves to simulate a carbon imbalance. We varied girdling intensity by removing phloem in increments of one-quarter of the circumference (zero, one--quarter, half, three-quarters, full) and surrounded a target branch with fully girdled ones to create a gradient in leaf carbohydrate content. Light saturated photosynthesis rate was measured in situ, and foliar respiration rate and leaf carbohydrate content were measured after destructive harvest at the end of the treatment. Girdling intensity created no consistent or strong responses in leaf carbohydrates. Glucose and fructose slightly increased in all species by 3.4% per one-quarter girdle, total carbon content and leaf mass per area increased only in one species by 5.4 and 5.5% per one-quarter girdle, and starch did not change. Only full girdling lowered photosynthesis in three of four species by 59-69%, but the decrease in photosynthesis was unrelated to the increase in glucose and fructose content. Girdling did not affect respiration. The results suggest that leaf carbohydrate content remains relatively constant under carbon imbalance, and any changes are unlikely to regulate photosynthesis or respiration. Because girdling also stops the export of hormones and reactive oxygen species, girdling may induce physiological changes unrelated to carbohydrate accumulation and may not be an effective method to study carbohydrate feedback

Low-carbohydrate diets for type 1 diabetes mellitus: A systematic review.

PubMed

Turton, Jessica L; Raab, Ron; Rooney, Kieron B

2018-01-01

Type 1 diabetes is an autoimmune condition characterised by pancreatic beta cell destruction and absolute insulin deficiency. The strongest predictor of diabetes complications is glycaemic control and achieving HbA1c ≤ 7.0% is the primary management target. However, standard treatment appears to be lacking and adjunctive strategies require consideration. A systematic review was conducted to examine the effect of low-carbohydrate diets on type 1 diabetes management. Four databases were searched from inception until 28 March 2017: MEDLINE; CINAHL; Cochrane Library; and EMBASE. All primary studies containing a methods section (excluding cross-sectional) were included. Reports had to quantitatively measure the effect(s) of a dietary intervention or observed intake over at least two weeks where carbohydrate is below 45% total energy in adults and/or children with type 1 diabetes. The primary outcome was HbA1c and secondary outcomes were severe hypoglycaemia, total daily insulin, BMI, quality of life and mean daily glucose. Seventy-nine full-text articles were assessed for eligibility and nine were included (two randomised controlled trials, four pre-post interventions, two case-series, one case-report). Eight studies reported a mean change in HbA1c with a low-carbohydrate diet. Of these, four reported a non-significant change (P ≥ 0.05) and three reported statistically significant reductions (P < 0.05). Two studies reported severe hypoglycaemia, five reported total insulin, three reported BMI, and one reported blood glucose. Due to the significant heterogeneity of included studies, an overall effect could not be determined. This review presents all available evidence on low-carbohydrate diets for type 1 diabetes and suggests an urgent need for more primary studies.

One strike against low-carbohydrate diets

USDA-ARS?s Scientific Manuscript database

There is intense controversy over whether low-carbohydrate or low-fat diets are more efficacious for weight management. Using precise methodology, Hall et al. (2015) demonstrated that a low-carbohydrate diet promoted greater fat oxidation than an isocaloric low-fat diet but, in contrast to popular s...

Health Effects of Low-Carbohydrate Diets: Where Should New Research Go?

PubMed Central

Wylie-Rosett, Judith; Aebersold, Karin; Conlon, Beth; Isasi, Carmen R.; Ostrovsky, Natania W.

2013-01-01

There has been considerable debate about the metabolic effects of restricting carbohydrate intake in weight and diabetes management. However, the American Diabetes Association has noted that weight and metabolic improvements can be achieved with low carbohydrate, low fat (implicitly higher carbohydrate), or a Mediterranean style diet (usually an intermediate level of carbohydrate). Our paper addresses variability in the definition for low or restricted carbohydrate, the effects of carbohydrate restriction on diabetes-related health outcomes, strategies for restricting carbohydrate intake, and potential genetic variability in response to dietary carbohydrate restriction. Issues for future research are also addressed. PMID:23266565

Bioinspired Pollen-Like Hierarchical Surface for Efficient Recognition of Target Cancer Cells.

PubMed

Wang, Wenshuo; Yang, Gao; Cui, Haijun; Meng, Jingxin; Wang, Shutao; Jiang, Lei

2017-08-01

The efficient recognition and isolation of rare cancer cells holds great promise for cancer diagnosis and prognosis. In nature, pollens exploit spiky structures to realize recognition and adhesion to stigma. Herein, a bioinspired pollen-like hierarchical surface is developed by replicating the assembly of pollen grains, and efficient and specific recognition to target cancer cells is achieved. The pollen-like surface is fabricated by combining filtering-assisted assembly and soft lithography-based replication of pollen grains of wild chrysanthemum. After modification with a capture agent specific to cancer cells, the pollen-like surface enables the capture of target cancer cells with high efficiency and specificity. In addition, the pollen-like surface not only assures high viability of captured cells but also performs well in cell mixture system and at low cell density. This study represents a good example of constructing cell recognition biointerfaces inspired by pollen-stigma adhesion. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of dietary carbohydrate on gastroesophageal reflux disease.

PubMed

Wu, Keng-Liang; Kuo, Chung-Mou; Yao, Chih-Chien; Tai, Wei-Chen; Chuah, Seng-Kee; Lim, Chee-Sang; Chiu, Yi-Chun

2018-01-12

Acid changes in gastroesophageal reflux with vary component in the food have less been studied, especially carbohydrate. We plan to clarify the effect of different carbohydrate density on low esophageal acid and reflux symptoms of patients with gastroesophgeal reflux disease. Twelve patients (52 ± 12 years old; five female) with gastroesophageal reflux disease were recruited for the prospective crossover study. Each patient was invited for panendoscope, manometry and 24 h pH monitor. The two formulated liquid meal, test meal A: 500 ml liquid meal (containing 84.8 g carbohydrate) and B: same volume liquid meal (but 178.8 g carbohydrate) were randomized supplied as lunch or dinner. Reflux symptoms were recorded. There are significant statistic differences in more Johnson-DeMeester score (p = 0.019), total reflux time (%) (p = 0.028), number of reflux periods (p = 0.026) and longest reflux (p = 0.015) after high carbohydrate diet than low carbohydrate. Total reflux time and number of long reflux periods more than 5 min are significant more after high carbohydrate diet. More acid reflux symptoms are found after high carbohydrate diet. High carbohydrate diet could induce more acid reflux in low esophagus and more reflux symptoms in patients with gastroesophageal reflux disease. Copyright © 2018. Published by Elsevier B.V.

Surface Proteins of Gram-Positive Bacteria and Mechanisms of Their Targeting to the Cell Wall Envelope

PubMed Central

Navarre, William Wiley; Schneewind, Olaf

1999-01-01

The cell wall envelope of gram-positive bacteria is a macromolecular, exoskeletal organelle that is assembled and turned over at designated sites. The cell wall also functions as a surface organelle that allows gram-positive pathogens to interact with their environment, in particular the tissues of the infected host. All of these functions require that surface proteins and enzymes be properly targeted to the cell wall envelope. Two basic mechanisms, cell wall sorting and targeting, have been identified. Cell well sorting is the covalent attachment of surface proteins to the peptidoglycan via a C-terminal sorting signal that contains a consensus LPXTG sequence. More than 100 proteins that possess cell wall-sorting signals, including the M proteins of Streptococcus pyogenes, protein A of Staphylococcus aureus, and several internalins of Listeria monocytogenes, have been identified. Cell wall targeting involves the noncovalent attachment of proteins to the cell surface via specialized binding domains. Several of these wall-binding domains appear to interact with secondary wall polymers that are associated with the peptidoglycan, for example teichoic acids and polysaccharides. Proteins that are targeted to the cell surface include muralytic enzymes such as autolysins, lysostaphin, and phage lytic enzymes. Other examples for targeted proteins are the surface S-layer proteins of bacilli and clostridia, as well as virulence factors required for the pathogenesis of L. monocytogenes (internalin B) and Streptococcus pneumoniae (PspA) infections. In this review we describe the mechanisms for both sorting and targeting of proteins to the envelope of gram-positive bacteria and review the functions of known surface proteins. PMID:10066836

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance.

PubMed

Baker, Lindsay B; Rollo, Ian; Stein, Kimberly W; Jeukendrup, Asker E

2015-07-14

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1-2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30-60 g/h in the form of a 6%-7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game

Association of Cell Surface Mucins with Galectin-3 Contributes to the Ocular Surface Epithelial Barrier*

PubMed Central

Argüeso, Pablo; Guzman-Aranguez, Ana; Mantelli, Flavio; Cao, Zhiyi; Ricciuto, Jessica; Panjwani, Noorjahan

2009-01-01

Maintenance of an intact mucosal barrier is critical to preventing damage to and infection of wet-surfaced epithelia. The mechanism of defense has been the subject of much investigation, and there is evidence now implicating O-glycosylated mucins on the epithelial cell surface. Here we investigate a new role for the carbohydrate-binding protein galectin-3 in stabilizing mucosal barriers through its interaction with mucins on the apical glycocalyx. Using the surface of the eye as a model system, we found that galectin-3 colocalized with two distinct membrane-associated mucins, MUC1 and MUC16, on the apical surface of epithelial cells and that both mucins bound to galectin-3 affinity columns in a galactose-dependent manner. Abrogation of the mucin-galectin interaction in four different mucosal epithelial cell types using competitive carbohydrate inhibitors of galectin binding, β-lactose and modified citrus pectin, resulted in decreased levels of galectin-3 on the cell surface with concomitant loss of barrier function, as indicated by increased permeability to rose bengal diagnostic dye. Similarly, down-regulation of mucin O-glycosylation using a stable tetracycline-inducible RNA interfering system to knockdown c1galt1 (T-synthase), a critical galactosyltransferase required for the synthesis of core 1 O-glycans, resulted in decreased cell surface O-glycosylation, reduced cell surface galectin-3, and increased epithelial permeability. Taken together, these results suggest that galectin-3 plays a key role in maintaining mucosal barrier function through carbohydrate-dependent interactions with cell surface mucins. PMID:19556244

The use of carbohydrates during exercise as an ergogenic aid.

PubMed

Cermak, Naomi M; van Loon, Luc J C

2013-11-01

Carbohydrate and fat are the two primary fuel sources oxidized by skeletal muscle tissue during prolonged (endurance-type) exercise. The relative contribution of these fuel sources largely depends on the exercise intensity and duration, with a greater contribution from carbohydrate as exercise intensity is increased. Consequently, endurance performance and endurance capacity are largely dictated by endogenous carbohydrate availability. As such, improving carbohydrate availability during prolonged exercise through carbohydrate ingestion has dominated the field of sports nutrition research. As a result, it has been well-established that carbohydrate ingestion during prolonged (>2 h) moderate-to-high intensity exercise can significantly improve endurance performance. Although the precise mechanism(s) responsible for the ergogenic effects are still unclear, they are likely related to the sparing of skeletal muscle glycogen, prevention of liver glycogen depletion and subsequent development of hypoglycemia, and/or allowing high rates of carbohydrate oxidation. Currently, for prolonged exercise lasting 2-3 h, athletes are advised to ingest carbohydrates at a rate of 60 g·h⁻¹ (~1.0-1.1 g·min⁻¹) to allow for maximal exogenous glucose oxidation rates. However, well-trained endurance athletes competing longer than 2.5 h can metabolize carbohydrate up to 90 g·h⁻¹ (~1.5-1.8 g·min⁻¹) provided that multiple transportable carbohydrates are ingested (e.g. 1.2 g·min⁻¹ glucose plus 0.6 g·min⁻¹ of fructose). Surprisingly, small amounts of carbohydrate ingestion during exercise may also enhance the performance of shorter (45-60 min), more intense (>75 % peak oxygen uptake; VO(₂peak)) exercise bouts, despite the fact that endogenous carbohydrate stores are unlikely to be limiting. The mechanism(s) responsible for such ergogenic properties of carbohydrate ingestion during short, more intense exercise bouts has been suggested to reside in the central nervous

Two Genetic Loci Produce Distinct Carbohydrate-Rich Structural Components of the Pseudomonas aeruginosa Biofilm Matrix

PubMed Central

Friedman, Lisa; Kolter, Roberto

2004-01-01

Pseudomonas aeruginosa forms biofilms, which are cellular aggregates encased in an extracellular matrix. Molecular genetics studies of three common autoaggregative phenotypes, namely wrinkled colonies, pellicles, and solid-surface-associated biofilms, led to the identification of two loci, pel and psl, that are involved in the production of carbohydrate-rich components of the biofilm matrix. The pel gene cluster is involved in the production of a glucose-rich matrix material in P. aeruginosa strain PA14 (L. Friedman and R. Kolter, Mol. Microbiol. 51:675-690, 2004). Here we investigate the role of the pel gene cluster in P. aeruginosa strain ZK2870 and identify a second genetic locus, termed psl, involved in the production of a mannose-rich matrix material. The 11 predicted protein products of the psl genes are homologous to proteins involved in carbohydrate processing. P. aeruginosa is thus able to produce two distinct carbohydrate-rich matrix materials. Either carbohydrate-rich matrix component appears to be sufficient for mature biofilm formation, and at least one of them is required for mature biofilm formation in P. aeruginosa strains PA14 and ZK2870. PMID:15231777

Two genetic loci produce distinct carbohydrate-rich structural components of the Pseudomonas aeruginosa biofilm matrix.

PubMed

Friedman, Lisa; Kolter, Roberto

2004-07-01

Pseudomonas aeruginosa forms biofilms, which are cellular aggregates encased in an extracellular matrix. Molecular genetics studies of three common autoaggregative phenotypes, namely wrinkled colonies, pellicles, and solid-surface-associated biofilms, led to the identification of two loci, pel and psl, that are involved in the production of carbohydrate-rich components of the biofilm matrix. The pel gene cluster is involved in the production of a glucose-rich matrix material in P. aeruginosa strain PA14 (L. Friedman and R. Kolter, Mol. Microbiol. 51:675-690, 2004). Here we investigate the role of the pel gene cluster in P. aeruginosa strain ZK2870 and identify a second genetic locus, termed psl, involved in the production of a mannose-rich matrix material. The 11 predicted protein products of the psl genes are homologous to proteins involved in carbohydrate processing. P. aeruginosa is thus able to produce two distinct carbohydrate-rich matrix materials. Either carbohydrate-rich matrix component appears to be sufficient for mature biofilm formation, and at least one of them is required for mature biofilm formation in P. aeruginosa strains PA14 and ZK2870. Copyright 2004 American Society for Microbiology

Backscattering of sound from targets in an Airy caustic formed by a curved reflecting surface

NASA Astrophysics Data System (ADS)

Dzikowicz, Benjamin Robert

The focusing of a caustic associated with the reflection of a locally curved sea floor or surface affects the scattering of sound by underwater targets. The most elementary caustic formed when sound reflects off a naturally curved surface is an Airy caustic. The case of a spherical target is examined here. With a point source acting also as a receiver, a point target lying in a shadow region returns only one echo directly from the target. When the target is on the Airy caustic, there are two echoes: one path is directly to the target and the other focuses off the curved surface. Echoes may be focused in both directions, the doubly focused case being the largest and the latest echo. With the target in the lit region, these different paths produce multiple echoes. For a finite sized sphere near an Airy caustic, all these echoes are manifest, but they occur at shifted target positions. Echoes of tone bursts reflecting only once overlap and interfere with each other, as do those reflecting twice. Catastrophe theory is used to analyze the echo amplitudes arising from these overlaps. The echo pressure for single reflections is shown to have a dependence on target position described by an Airy function for both a point and a finite target. With double focusing, this dependence is the square of an Airy function for a point target. With a finite sized target, (as in the experiment) this becomes a hyperbolic umbilic catastrophe integral with symmetric arguments. The arguments of each of these functions are derived from only the relative echo times of a transient pulse. Transient echo times are calculated using a numerical ray finding technique. Experiment confirms the predicted merging of transient echoes in the time domain, as well as the Airy and hyperbolic umbilic diffraction integral amplitudes for a tone burst. This method allows targets to be observed at greater distances in the presence of a focusing surface.

Carbohydrates and T cells: A sweet twosome

PubMed Central

Avci, Fikri Y.; Li, Xiangming; Tsuji, Moriya; Kasper, Dennis L.

2013-01-01

Carbohydrates as T cell-activating antigens have been generating significant interest. For many years, carbohydrates were thought of as T-independent antigens, however, more recent research had demonstrated that mono- or oligosaccharides glycosidically-linked to peptides can be recognized by T cells. T cell recognition of these glycopeptides depends on the structure of both peptide and glycan portions of the antigen. Subsequently, it was discovered that natural killer T cells recognized glycolipids when presented by the antigen presenting molecule CD1d. A transformative insight into glycan-recognition by T cells occurred when zwitterionic polysaccharides were discovered to bind to and be presented by MHCII to CD4+ T cells. Based on this latter observation, the role that carbohydrate epitopes generated from glycoconjugate vaccines had in activating helper T cells was explored and it was found that these epitopes are presented to specific carbohydrate recognizing T cells through a unique mechanism. Here we review the key interactions between carbohydrate antigens and the adaptive immune system at the molecular, cellular and systems levels exploring the significant biological implications in health and disease. PMID:23757291

Exploring the free-energy landscape of carbohydrate-protein complexes: development and validation of scoring functions considering the binding-site topology

NASA Astrophysics Data System (ADS)

Eid, Sameh; Saleh, Noureldin; Zalewski, Adam; Vedani, Angelo

2014-12-01

Carbohydrates play a key role in a variety of physiological and pathological processes and, hence, represent a rich source for the development of novel therapeutic agents. Being able to predict binding mode and binding affinity is an essential, yet lacking, aspect of the structure-based design of carbohydrate-based ligands. We assembled a diverse data set comprising 273 carbohydrate-protein crystal structures with known binding affinity and evaluated the prediction accuracy of a large collection of well-established scoring and free-energy functions, as well as combinations thereof. Unfortunately, the tested functions were not capable of reproducing binding affinities in the studied complexes. To simplify the complex free-energy surface of carbohydrate-protein systems, we classified the studied proteins according to the topology and solvent exposure of the carbohydrate-binding site into five distinct categories. A free-energy model based on the proposed classification scheme reproduced binding affinities in the carbohydrate data set with an r 2 of 0.71 and root-mean-squared-error of 1.25 kcal/mol ( N = 236). The improvement in model performance underlines the significance of the differences in the local micro-environments of carbohydrate-binding sites and demonstrates the usefulness of calibrating free-energy functions individually according to binding-site topology and solvent exposure.

Very low-carbohydrate versus isocaloric high-carbohydrate diet in dietary obese rats.

PubMed

Axen, Kathleen V; Axen, Kenneth

2006-08-01

The effects of a very low-carbohydrate (VLC), high-fat (HF) dietary regimen on metabolic syndrome were compared with those of an isocaloric high-carbohydrate (HC), low-fat (LF) regimen in dietary obese rats. Male Sprague-Dawley rats, made obese by 8 weeks ad libitum consumption of an HF diet, developed features of the metabolic syndrome vs. lean control (C) rats, including greater visceral, subcutaneous, and hepatic fat masses, elevated plasma cholesterol levels, impaired glucose tolerance, and fasting and post-load insulin resistance. Half of the obese rats (VLC) were then fed a popular VLC-HF diet (Weeks 9 and 10 at 5% and Weeks 11 to 14 at 15% carbohydrate), and one-half (HC) were pair-fed an HC-LF diet (Weeks 9 to 14 at 60% carbohydrate). Energy intakes of pair-fed VLC and HC rats were less than C rats throughout Weeks 9 to 14. Compared with HC rats, VLC rats exhibited impaired insulin and glycemic responses to an intraperitoneal glucose load at Week 10 and lower plasma triacylglycerol levels but retarded loss of hepatic, retroperitoneal, and total body fat at Week 14. VLC, HC, and C rats no longer differed in body weight, plasma cholesterol, glucose tolerance, or fasting insulin resistance at Week 14. Progressive decreases in fasting insulin resistance in obese groups paralleled concomitant reductions in hepatic, retroperitoneal, and total body fat. When energy intake was matched, the VLC-HF diet provided no advantage in weight loss or in improving those components of the metabolic syndrome induced by dietary obesity and may delay loss of hepatic and visceral fat as compared with an HC-LF diet.

Low Carbohydrate and Moderately Fat-Reduced Diets Similarly Affected Early Weight Gain in Varenicline-Treated Overweight or Obese Smokers.

PubMed

Heggen, Eli; Svendsen, Mette; Klemsdal, Tor Ole; Tonstad, Serena

2016-06-01

Weight gain is common when stopping smoking. This study compared the effect of advising smokers to follow a diet low in carbohydrates versus a usual fat-reduced diet on weight gain and nicotine withdrawal. In a randomized clinical trial, 122 men and women smokers with body mass index 25-40kg/m(2) were assigned low-carbohydrate versus moderately fat-reduced diets. Within a week thereafter all participants started treatment with a 12-week course of varenicline 10 days prior to the target quit date. Brief dietary and motivational counseling was given at all visits. Self-reported abstinence was validated. Protein intake in the low-carbohydrate versus fat-reduced diets was 26.4% of total energy versus 20.0%, fat 38.2% versus 30.1%, and carbohydrates 29.0% versus 41.7% (all P < .001). Mean weight changes for the low-carbohydrate versus fat-reduced groups were -1.2 (SD 2.2) versus -0.5 (SD 2.0) kg, -0.2 (SD 3.3) versus 0.5 (SD 2.6) kg, and 2.2 (SD 4.5) versus 2.1 (SD 3.9) kg at 4, 12, and 24 weeks after the target quit date, respectively (not statistically significant). Smoking abstinence rates did not differ between diets. In the combined groups, point prevalence abstinence rates were 71.0% at 12 weeks and 46.3% at 24 weeks. The Minnesota Nicotine Withdrawal Symptoms score was lower in the fat-reduced group compared with the low-carbohydrate group at weeks 4 and 12. In overweight or obese smokers using varenicline a low-carbohydrate diet was no better than a fat-reduced diet in reducing weight gain but may result in more severe nicotine withdrawal symptoms. Compared to previous studies, cessation rates with varenicline were not impaired by dietary counseling. The study implies that a popular low-carbohydrate diet does not result in greater weight loss than a moderately fat-reduced diet in overweight and obese smokers who are attempting to quit smoking with the aid of varenicline. Dietary counseling combined with varenicline treatment did not appear to unfavorably

In vitro evaluation of biodegradable microspheres with surface-bound ligands.

PubMed

Keegan, Mark E; Royce, Sara M; Fahmy, Tarek; Saltzman, W Mark

2006-02-21

Protein ligands were conjugated to the surface of biodegradable microspheres. These microsphere-ligand conjugates were then used in two in vitro model systems to evaluate the effect of conjugated ligands on microsphere behavior. Microsphere retention in agarose columns was increased by ligands on the microsphere surface specific for receptors on the agarose matrix. In another experiment, conjugating the lectin Ulex europaeus agglutinin 1 to the microsphere surface increased microsphere adhesion to Caco-2 monolayers compared to control microspheres. This increase in microsphere adhesion was negated by co-administration of l-fucose, indicating that the increase in adhesion is due to specific interaction of the ligand with carbohydrate receptors on the cell surface. These results demonstrate that the ligands conjugated to the microspheres maintain their receptor binding activity and are present on the microsphere surface at a density sufficient to target the microspheres to both monolayers and three-dimensional matrices bearing complementary receptors.

Surface Modification of ICF Target Capsules by Pulsed Laser Ablation

DOE PAGES

Carlson, Lane C.; Johnson, Michael A.; Bunn, Thomas L.

2016-06-30

Topographical modifications of spherical surfaces are imprinted on National Ignition Facility (NIF) target capsules by extending the capabilities of a recently developed full surface (4π) laser ablation and mapping apparatus. The laser ablation method combines the precision, energy density and long reach of a focused laser beam to pre-impose sinusoidal modulations on the outside surface of High Density Carbon (HDC) capsules and the inside surface of Glow Discharge Polymer (GDP) capsules. Sinusoidal modulations described in this paper have sub-micron to 10’s of microns vertical scale and wavelengths as small as 30 μm and as large as 200 μm. The modulatedmore » patterns are created by rastering a focused laser fired at discrete capsule surface locations for a specified number of pulses. The computer program developed to create these raster patterns uses inputs such as laser beam intensity profile, the material removal function, the starting surface figure and the desired surface figure. The patterns are optimized to minimize surface roughness. Lastly, in this paper, simulated surfaces are compared with actual ablated surfaces measured using confocal microscopy.« less

Preoperative oral carbohydrates and postoperative insulin resistance.

PubMed

Nygren, J; Soop, M; Thorell, A; Sree Nair, K; Ljungqvist, O

1999-04-01

Infusions of carbohydrates before surgery have been shown to reduce postoperative insulin resistance. Presently, we investigated the effects of a carbohydrate drink, given shortly before surgery, on postoperative insulin sensitivity. Insulin sensitivity and glucose turnover ([6, 6,(2)H(2)]-D-glucose) were measured using hyper-insulinemic, normoglycemic clamps before and after elective surgery. Sixteen patients undergoing total hip replacement were randomly assigned to preoperative oral carbohydrate administration (CHO-H, n = 8) or the same amount of a placebo drink (placebo, n = 8) before surgery. Insulin sensitivity was measured before and immediately after surgery. Patients undergoing elective colorectal surgery were studied before surgery and 24 h postoperatively (CHO-C (n = 7), and fasted (n = 7), groups). The fasted group underwent surgery after an overnight fast. In both studies, the CHO groups received 800 ml of an isoosmolar carbohydrate rich beverage the evening before the operation (100g carbohydrates), as well as another 400 ml (50g carbohydrates) 2 h before the initiation of anesthesia. Immediately after surgery, insulin sensitivity was reduced 37% in the placebo group (P < 0.05 vs. preoperatively) while no significant change was found in the CHO-H group (-16%, p = NS). During clamps performed 24h postoperatively, insulin sensitivity and whole-body glucose disposal was reduced in both groups, but the reduction was greater compared to that in the CHO-C group (-49 +/- 6% vs. -26 +/- 8%, P> 0.05 fasted vs. CHO-C). Patients given a carbohydrate drink shortly before elective surgery displayed less reduced insulin sensitivity after surgery as compared to patients undergoing surgery after an overnight fast. Copyright 1999 Harcourt Publishers Ltd.

Physicochemical Characterization of Iron Carbohydrate Colloid Drug Products.

PubMed

Zou, Peng; Tyner, Katherine; Raw, Andre; Lee, Sau

2017-09-01

Iron carbohydrate colloid drug products are intravenously administered to patients with chronic kidney disease for the treatment of iron deficiency anemia. Physicochemical characterization of iron colloids is critical to establish pharmaceutical equivalence between an innovator iron colloid product and generic version. The purpose of this review is to summarize literature-reported techniques for physicochemical characterization of iron carbohydrate colloid drug products. The mechanisms, reported testing results, and common technical pitfalls for individual characterization test are discussed. A better understanding of the physicochemical characterization techniques will facilitate generic iron carbohydrate colloid product development, accelerate products to market, and ensure iron carbohydrate colloid product quality.

Single tag for total carbohydrate analysis.

PubMed

Anumula, Kalyan Rao

2014-07-15

Anthranilic acid (2-aminobenzoic acid, 2-AA) has the remarkable property of reacting rapidly with every type of reducing carbohydrate. Reactivity of 2-AA with carbohydrates in aqueous solutions surpasses all other tags reported to date. This unique capability is attributed to the strategically located -COOH which accelerates Schiff base formation. Monosaccharides, oligosaccharides (N-, O-, and lipid linked and glycans in secretory fluids), glycosaminoglycans, and polysaccharides can be easily labeled with 2-AA. With 2-AA, labeling is simple in aqueous solutions containing proteins, peptides, buffer salts, and other ingredients (e.g., PNGase F, glycosidase, and transferase reaction mixtures). In contrast, other tags require relatively pure glycans for labeling in anhydrous dimethyl sulfoxide-acetic acid medium. Acidic conditions are known to cause desialylation, thus requiring a great deal of attention to sample preparation. Simpler labeling is achieved with 2-AA within 30-60 min in mild acetate-borate buffered solution. 2-AA provides the highest sensitivity and resolution in chromatographic methods for carbohydrate analysis in a simple manner. Additionally, 2-AA is uniquely qualified for quantitative analysis by mass spectrometry in the negative mode. Analyses of 2-AA-labeled carbohydrates by electrophoresis and other techniques have been reported. Examples cited here demonstrate that 2-AA is the universal tag for total carbohydrate analysis. Copyright © 2014 Elsevier Inc. All rights reserved.

Treatment of ovarian cancer by targeting the tumor stem cell-associated carbohydrate antigen, Sialyl-Thomsen-nouveau

PubMed Central

Starbuck, Kristen; Al-Alem, Linah; Eavarone, David A.; Hernandez, Silvia Fatima; Bellio, Chiara; Prendergast, Jillian M.; Stein, Jenna; Dransfield, Daniel T.; Zarrella, Bianca; Growdon, Whitfield B.; Behrens, Jeff; Foster, Rosemary; Rueda, Bo R.

2018-01-01

Recurrent ovarian cancer (OvCa) is thought to result in part from the inability to eliminate rare quiescent cancer stem cells (CSCs) that survive cytotoxic chemotherapy and drive tumor resurgence. The Sialyl-Thomsen-nouveau antigen (STn) is a carbohydrate moiety present on protein markers of CSCs in pancreatic, colon, and gastric malignancies. We have demonstrated that human OvCa cell lines contain varying levels of cells that independently express either STn or the ovarian CSC marker CD133. Here we determine co-expression of STn and CD133 in a subset of human OvCa cell lines. Analyses of colony and sphere forming capacity and of response to standard-of-care cytotoxic therapy suggest a subset of OvCa STn+ cells display some CSC features. The effect of the anti-STn antibody-drug conjugates (ADCs) S3F-CL-MMAE and 2G12-2B2-CL-MMAE on OvCa cell viability in vitro and in vivo was also assessed. Treatment with S3F-CL-MMAE reduced the viability of two of three OvCa cell lines in vitro and exposure to either S3F-CL-MMAE or 2G12-2B2-CL-MMAE reduced OVCAR3-derived xenograft volume in vivo, depleting STn+ tumor cells. In summary, STn+ cells demonstrate some stem-like properties and specific therapeutic targeting of STn in ovarian tumors may be an effective clinical strategy to eliminate both STn+ CSC and STn+ non-CSC populations. PMID:29796189

Augmented liver targeting of exosomes by surface modification with cationized pullulan.

PubMed

Tamura, Ryo; Uemoto, Shinji; Tabata, Yasuhiko

2017-07-15

Exosomes are membrane nanoparticles containing biological substances that are employed as therapeutics in experimental inflammatory models. Surface modification of exosomes for better tissue targetability and enhancement of their therapeutic ability was recently attempted mainly using gene transfection techniques. Here, we show for the first time that the surface modification of exosomes with cationized pullulan, which has the ability to target hepatocyte asialoglycoprotein receptors, can target injured liver and enhance the therapeutic effect of exosomes. Surface modification can be achieved by a simple mixing of original exosomes and cationized pullulan and through an electrostatic interaction of both substances. The exosomes modified with cationized pullulan were internalized into HepG2 cells in vitro to a significantly greater extent than unmodified ones and this internalization was induced through the asialoglycoprotein receptor that was specifically expressed on HepG2 cells and hepatocytes. When injected intravenously into mice with concanavalin A-induced liver injury, the modified exosomes accumulated in the liver tissue, resulting in an enhanced anti-inflammatory effect in vivo. It is concluded that the surface modification with cationized pullulan promoted accumulation of the exosomes in the liver and the subsequent biological function, resulting in a greater therapeutic effect on liver injury. Exosomes have shown potentials as therapeutics for various inflammatory disease models. This study is the first to show the specific accumulation of exosomes in the liver and enhanced anti-inflammatory effect via the surface modification of exosomes using pullulan, which is specifically recognized by the asialoglycoprotein receptor (AGPR) on HepG2 cells and hepatocytes. The pullulan was expressed on the surface of PKH-labeled exosomes, and it led increased accumulation of PKH into HepG2 cells, whereas the accumulation was canceled by AGPR inhibitor. In the mouse

Distributions of phytoplankton carbohydrate, protein and lipid in the world oceans from satellite ocean colour.

PubMed

Roy, Shovonlal

2018-06-01

Energy value of phytoplankton regulates the growth of higher trophic species, affecting the tropic balance and sustainability of marine food webs. Therefore, developing our capability to estimate and monitor, on a global scale, the concentrations of macromolecules that determine phytoplankton energy value, would be invaluable. Reported here are the first estimates of carbohydrate, protein, lipid, and overall energy value of phytoplankton in the world oceans, using ocean-colour data from satellites. The estimates are based on a novel bio-optical method that utilises satellite-derived bio-optical fingerprints of living phytoplankton combined with allometric relationships between phytoplankton cells and cellular macromolecular contents. The annually averaged phytoplankton energy value, per cubic metre of sub-surface ocean, varied from less than 0.1 kJ in subtropical gyres, to 0.5-1.0 kJ in parts of the equatorial, northern and southern latitudes, and rising to >10 kJ in certain coastal and optically complex waters. The annually averaged global stocks of carbohydrate, protein and lipid were 0.044, 0.17 and 0.108 gigatonnes, respectively, with monthly stocks highest in September and lowest in June, over 1997-2013. The fractional contributions of phytoplankton size classes e.g., picoplankton, nanoplankton and microplankton to surface concentrations and global stocks of macromolecules varied considerably across marine biomes classified as Longhurst provinces. Among these provinces, the highest annually averaged surface concentrations of carbohydrate, protein, and lipid were in North-East Atlantic Coastal Shelves, whereas, the lowest concentration of carbohydrate or lipid were in North Atlantic Tropical Gyral, and that of protein was in North Pacific Subtropical Gyre West. The regional accuracy of the estimates and their sensitivity to satellite inputs are quantified from the bio-optical model, which show promise for possible operational monitoring of phytoplankton

WURCS 2.0 Update To Encapsulate Ambiguous Carbohydrate Structures.

PubMed

Matsubara, Masaaki; Aoki-Kinoshita, Kiyoko F; Aoki, Nobuyuki P; Yamada, Issaku; Narimatsu, Hisashi

2017-04-24

Accurate representation of structural ambiguity is important for storing carbohydrate structures containing varying levels of ambiguity in the literature and databases. Although many representations for carbohydrates have been developed in the past, a generalized but discrete representation format did not exist. We had previously developed the Web3 Unique Representation of Carbohydrate Structures (WURCS) in an attempt to define a generalizable and unique linear representation for carbohydrate structures. However, it lacked sufficient rules to uniquely describe ambiguous structures. In this work, we updated WURCS to handle such ambiguous monosaccharide structures. In particular, to handle structural ambiguity around (potential) carbonyl groups incidental to the carbohydrate analysis, we defined a representation of backbone carbons containing atomic-level ambiguity. As a result, we show that WURCS 2.0 can represent a wider variety of carbohydrate structures containing ambiguous monosaccharides, such as those whose ring closure is undefined or whose anomeric information is only known. This new format provides a representation of carbohydrates that was not possible before, and it is currently being used by the International Glycan Structure Repository GlyTouCan.

The visible ground surface as a reference frame for scaling binocular depth of a target in midair

PubMed Central

WU, JUN; ZHOU, LIU; SHI, PAN; HE, ZIJIANG J; OOI, TENG LENG

2014-01-01

The natural ground surface carries texture information that extends continuously from one’s feet to the horizon, providing a rich depth resource for accurately locating an object resting on it. Here, we showed that the ground surface’s role as a reference frame also aids in locating a target suspended in midair based on relative binocular disparity. Using real world setup in our experiments, we first found that a suspended target is more accurately localized when the ground surface is visible and the observer views the scene binocularly. In addition, the increased accuracy occurs only when the scene is viewed for 5 sec rather than 0.15 sec, suggesting that the binocular depth process takes time. Second, we found that manipulation of the configurations of the texture-gradient and/or linear-perspective cues on the visible ground surface affects the perceived distance of the suspended target in midair. Third, we found that a suspended target is more accurately localized against a ground texture surface than a ceiling texture surface. This suggests that our visual system usesthe ground surface as the preferred reference frame to scale the distance of a suspended target according to its relative binocular disparity. PMID:25384237

Highly Sensitive Detection of Target Biomolecules on Cell Surface Using Gold Nanoparticle Conjugated with Aptamer Probe

NASA Astrophysics Data System (ADS)

Kim, Hyonchol; Terazono, Hideyuki; Hayashi, Masahito; Takei, Hiroyuki; Yasuda, Kenji

2012-06-01

A method of gold nanoparticle (Au NP) labeling with backscattered electron (BE) imaging of field emission scanning electron microscopy (FE-SEM) was applied for specific detection of target biomolecules on a cell surface. A single-stranded DNA aptamer, which specifically binds to the target molecule on a human acute lymphoblastic leukemia cell, was conjugated with a 20 nm Au NP and used as a probe to label its target molecule on the cell. The Au NP probe was incubated with the cell, and the interaction was confirmed using BE imaging of FE-SEM through direct counting of the number of Au NPs attached on the target cell surface. Specific Au NP-aptamer probes were observed on a single cell surface and their spatial distributions including submicron-order localizations were also clearly visualized, whereas the nonspecific aptamer probes were not observed on it. The aptamer probe can be potentially dislodged from the cell surface with treatment of nucleases, indicating that Au NP-conjugated aptamer probes can be used as sensitive and reversible probes to label target biomolecules on cells.

Carbohydrate Metabolism Disorders

MedlinePlus

Metabolism is the process your body uses to make energy from the food you eat. Food is ... disorder, something goes wrong with this process. Carbohydrate metabolism disorders are a group of metabolic disorders. Normally ...

Rear surface light emission measurements from laser-produced shock waves in clear and Al-coated polystyrene targets

NASA Astrophysics Data System (ADS)

McLean, E. A.; Deniz, A. V.; Schmitt, A. J.; Stamper, J. A.; Obenschain, S. P.; Lehecka, T.; Mostovych, A. N.; Seely, J.

1999-08-01

The Nike KrF laser, with its very uniform focal distributions, has been used at intensities near 10 14 W/cm 2 to launch shock waves in polystyrene targets. The rear surface visible light emission differed between clear polystyrene (CH) targets and targets with a thin (125 nm) Al coating on the rear side. The uncoated CH targets showed a relatively slowly rising emission followed by a sudden fall when the shock emerges, while the Al-coated targets showed a rapid rise in emission when the shock emerges followed by a slower fall, allowing an unambiguous determination of the time the shock arrived at the rear surface. A half-aluminized target allowed us to observe this difference in a single shot. The brightness temperature of both the aluminized targets and the non-aluminized targets was slightly below but close to rear surface temperature predictions of a hydrodynamic code. A discussion of preheat effects is given.

Perceived hunger is lower and weight loss is greater in overweight premenopausal women consuming a low-carbohydrate/high-protein vs high-carbohydrate/low-fat diet.

PubMed

Nickols-Richardson, Sharon M; Coleman, Mary Dean; Volpe, Joanne J; Hosig, Kathy W

2005-09-01

The impact of a low-carbohydrate/high-protein diet compared with a high-carbohydrate/low-fat diet on ratings of hunger and cognitive eating restraint were examined. Overweight premenopausal women consumed a low-carbohydrate/high-protein (n=13) or high-carbohydrate/low-fat diet (n=15) for 6 weeks. Fasting body weight (BW) was measured and the Eating Inventory was completed at baseline, weeks 1 to 4, and week 6. All women experienced a reduction in BW (P<.01), although relative BW loss was greater in the low-carbohydrate/high-protein vs high-carbohydrate/low-fat group at week 6 (P<.05). Based on Eating Inventory scores, self-rated hunger decreased (P<.03) in women in the low-carbohydrate/high-protein but not in the high-carbohydrate/low-fat group from baseline to week 6. In both groups, self-rated cognitive eating restraint increased (P<.01) from baseline to week 1 and remained constant to week 6. Both diet groups reported increased cognitive eating restraint, facilitating short-term weight loss; however, the decrease in hunger perception in the low-carbohydrate/high-protein group may have contributed to a greater percentage of BW loss.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

PubMed Central

Baker, Lindsay B.; Rollo, Ian; Stein, Kimberly W.; Jeukendrup, Asker E.

2015-01-01

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a

A carbohydrate-anion recognition system in aprotic solvents.

PubMed

Ren, Bo; Dong, Hai; Ramström, Olof

2014-05-01

A carbohydrate-anion recognition system in nonpolar solvents is reported, in which complexes form at the B-faces of β-D-pyranosides with H1-, H3-, and H5-cis patterns similar to carbohydrate-π interactions. The complexation effect was evaluated for a range of carbohydrate structures; it resulted in either 1:1 carbohydrate-anion complexes, or 1:2 complex formation depending on the protection pattern of the carbohydrate. The interaction was also evaluated with different anions and solvents. In both cases it resulted in significant binding differences. The results indicate that complexation originates from van der Waals interactions or weak CH⋅⋅⋅A(-) hydrogen bonds between the binding partners and is related to electron-withdrawing groups of the carbohydrates as well as increased hydrogen-bond-accepting capability of the anions. © 2014 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

Target Surface Area Effects on Hot Electron Dynamics from High Intensity Laser-Plasma Interactions

DTIC Science & Technology

2016-08-19

New J. Phys. 18 (2016) 063020 doi:10.1088/1367-2630/18/6/063020 PAPER Target surface area effects on hot electron dynamics from high intensity laser ...Science, University ofMichigan, AnnArbor,MI 48109-2099, USA E-mail: czulick@umich.edu Keywords: laser -plasma,mass-limited, fast electrons, sheath...field Abstract Reduced surface area targets were studied using an ultra-high intensity femtosecond laser in order to determine the effect of electron

Simple carbohydrates (image)

MedlinePlus

... the body to be used as energy. Simple carbohydrates are found naturally in foods such as fruits, milk, and milk products. They are also found in processed and refined sugars such as candy, table sugar, ...

Carbohydrate recognition: A minimalistic approach to binding

NASA Astrophysics Data System (ADS)

Kubik, Stefan

2012-09-01

Synthetic receptors with properties resembling those of carbohydrate-binding proteins are known, but they are structurally rather complex. Elaborate structures are, however, not always required to bind carbohydrates in water -- much simpler compounds can be just as effective.

Influence of the π-coordinated arene on the anticancer activity of ruthenium(II) carbohydrate organometallic complexes

NASA Astrophysics Data System (ADS)

Hanif, Muhammad; Meier, Samuel; Nazarov, Alexey; Risse, Julie; Legin, Anton; Casini, Angela; Jakupec, Michael; Keppler, Bernhard; Hartinger, Christian

2013-10-01

The synthesis and in vitro cytotoxicity of a series of RuII(arene) complexes with carbohydrate-derived phosphite ligands and various arene co-ligands is described. The arene ligand has a strong influence on the in vitro anticancer activity of this series of compounds, which correlates fairly well with cellular accumulation. The most lipophilic compound bearing a biphenyl moiety and a cyclohexylidene-protected carbohydrate is the most cytotoxic with unprecedented IC50 values for the compound class in three human cancer cell lines. This compound shows reactivity to the DNA model nucleobase 9-ethylguanine, but does not alter the secondary structure of plasmid DNA indicating that other biological targets are responsible for its cytotoxic effect.

Carbohydrates and sports practice: a Twitter virtual ethnography

PubMed

Rodríguez-Martín, Beatriz; Castillo, Carlos Alberto

2017-02-01

Introduction: Although carbohydrates consumption is a key factor to enhance sport performance, intake levels seem questioned by some amateur athletes, leading to develop an irrational aversion to carbohydrate known as “carbophobia”. On the other hand, food is the origin of virtual communities erected as a source of knowledge and a way to exchange information. Despite this, very few studies have analysed the influence of social media in eating behaviours. Objectives: To know the conceptualizations about carbohydrates intake and eating patterns related to carbophobia expressed in amateur athletes’ Twitter accounts. Methods: Qualitative research designed from Hine’s Virtual Ethnography. Virtual immersion was used for data collection in Twitter open accounts in a theoretical sample of tweets from amateur athletes. Discourse analysis of narrative information of tweets was carried out through open, axial and selective coding process and the constant comparison method. Results: Data analysis revealed four main categories that offered a picture of conceptualizations of carbohydrates: carbohydrates as suspects or guilty from slowing down training, carbophobia as a lifestyle, carbophobia as a religion and finally the love/hate relationship with carbohydrates. Conclusions: Low-carbohydrate diet is considered a healthy lifestyle in some amateur athletes. The results of this study show the power of virtual communication tools such as Twitter to support, promote and maintain uncommon and not necessarily healthy eating behaviours. Future studies should focus on the context in which these practices appear.

Saturated fat, carbohydrate, and cardiovascular disease.

PubMed

Siri-Tarino, Patty W; Sun, Qi; Hu, Frank B; Krauss, Ronald M

2010-03-01

A focus of dietary recommendations for cardiovascular disease (CVD) prevention and treatment has been a reduction in saturated fat intake, primarily as a means of lowering LDL-cholesterol concentrations. However, the evidence that supports a reduction in saturated fat intake must be evaluated in the context of replacement by other macronutrients. Clinical trials that replaced saturated fat with polyunsaturated fat have generally shown a reduction in CVD events, although several studies showed no effects. An independent association of saturated fat intake with CVD risk has not been consistently shown in prospective epidemiologic studies, although some have provided evidence of an increased risk in young individuals and in women. Replacement of saturated fat by polyunsaturated or monounsaturated fat lowers both LDL and HDL cholesterol. However, replacement with a higher carbohydrate intake, particularly refined carbohydrate, can exacerbate the atherogenic dyslipidemia associated with insulin resistance and obesity that includes increased triglycerides, small LDL particles, and reduced HDL cholesterol. In summary, although substitution of dietary polyunsaturated fat for saturated fat has been shown to lower CVD risk, there are few epidemiologic or clinical trial data to support a benefit of replacing saturated fat with carbohydrate. Furthermore, particularly given the differential effects of dietary saturated fats and carbohydrates on concentrations of larger and smaller LDL particles, respectively, dietary efforts to improve the increasing burden of CVD risk associated with atherogenic dyslipidemia should primarily emphasize the limitation of refined carbohydrate intakes and a reduction in excess adiposity.

Validation of lignocellulosic biomass carbohydrates determination via acid hydrolysis.

PubMed

Zhou, Shengfei; Runge, Troy M

2014-11-04

This work studied the two-step acid hydrolysis for determining carbohydrates in lignocellulosic biomass. Estimation of sugar loss based on acid hydrolyzed sugar standards or analysis of sugar derivatives was investigated. Four model substrates (starch, holocellulose, filter paper and cotton) and three levels of acid/material ratios (7.8, 10.3 and 15.4, v/w) were studied to demonstrate the range of test artifacts. The method for carbohydrates estimation based on acid hydrolyzed sugar standards having the most satisfactory carbohydrate recovery and relative standard deviation. Raw material and the acid/material ratio both had significant effect on carbohydrate hydrolysis, suggesting the acid to have impacts beyond a catalyst in the hydrolysis. Following optimal procedures, we were able to reach a carbohydrate recovery of 96% with a relative standard deviation less than 3%. The carbohydrates recovery lower than 100% was likely due to the incomplete hydrolysis of substrates, which was supported by scanning electron microscope (SEM) images. Copyright © 2014 Elsevier Ltd. All rights reserved.

Carbohydrate absorption from one serving of fruit juice in young children: age and carbohydrate composition effects.

PubMed

Nobigrot, T; Chasalow, F I; Lifshitz, F

1997-04-01

To test the hypotheses that: the efficiency of carbohydrate absorption in childhood increases with age, and decreased carbohydrate absorption occurs more frequently with juices containing more fructose than glucose and/or sorbitol than with juices which contain equal amounts of fructose and glucose and are sorbitol-free. One hundred and four healthy children were recruited from the Ambulatory Center at Maimonides Children's Center. They were assigned to one of three age groups: approximately 1, 3 and 5 years of age. Each child received one age-specific dose (by randomization) of one of four juices: a) pear juice which contains fructose in excess to glucose and a large amount of sorbitol; b) apple juice which is similar to pear juice in its fructose to glucose ratio but contains four times less sorbitol than pear juice; c) white grape juice or d) purple grape juice both of which contain equal amounts of fructose and glucose and are sorbitol-free. Breath hydrogen excretion (BH2) was utilized as the index of carbohydrate absorption. It was measured in fasting children and at 30-minute intervals for 3 hours after drinking the single serving of juice. Multiple breath hydrogen related parameters were quantified and results were expressed as: BH2 peak, area under the curve, and degree of carbohydrate malabsorption. After the test, parents completed a questionnaire and recorded signs and symptoms of intestinal malabsorption for 24 hours. Pear juice related BH2 levels were significantly higher among children 1 and 3 years of age as compared to the levels achieved after the other juices. Apple juice related BH2 levels were significantly higher only among the youngest age group of children. There was no significant difference in carbohydrate absorption among the 5 year old children regardless of the juice consumed. Incomplete carbohydrate absorption (BH2 peak above 20 ppm) occurred more frequently after pear juice consumption (84%) than after apple juice (41%) or grape juice

Carbohydrate Dehydration Demonstrations.

ERIC Educational Resources Information Center

Dolson, David A.; And Others

1995-01-01

Discusses the impact of various factors on the "charring reaction" of a carbohydrate with concentrated sulfuric acid including the type of sugar, the degree of fineness of the sugar crystals, and the amount of water added. (JRH)

Inquiry-Based Approach to a Carbohydrate Analysis Experiment

NASA Astrophysics Data System (ADS)

Senkbeil, Edward G.

1999-01-01

The analysis of an unknown carbohydrate in an inquiry-based learning format has proven to be a valuable and interesting undergraduate biochemistry laboratory experiment. Students are given a list of carbohydrates and a list of references for carbohydrate analysis. The references contain a variety of well-characterized wet chemistry and instrumental techniques for carbohydrate identification, but the students must develop an appropriate sequential protocol for unknown identification. The students are required to provide a list of chemicals and procedures and a flow chart for identification before the lab. During the 3-hour laboratory period, they utilize their accumulated information and knowledge to classify and identify their unknown. Advantages of the inquiry-based format are (i) students must be well prepared in advance to be successful in the laboratory, (ii) students feel a sense of accomplishment in both designing and carrying out a successful experiment, and (iii) the carbohydrate background information digested by the students significantly decreases the amount of lecture time required for this topic.

Impact of Carbohydrate Restriction on Healthy Adolescent Development.

PubMed

Richmond, Hannah M; Duriancik, David M

2017-09-01

Carbohydrate-restricted diets are known for their impact on weight loss; however, research is still required to determine if low-carbohydrate diets are safe for adolescents. Carbohydrates directly stimulate an insulin response, and studies have recently shown that insulin and binding to respective insulin receptors (IRs) are critical in Kisspeptin (Kiss1) neuronal development. These neurons directly stimulate gonadotropin-releasing hormone, which activates the pituitary-gonadal axis during puberty. This information suggests that carbohydrate restriction may delay pubertal development in adolescents due to the impact on insulin and Kiss1 transcription. Studies have observed disturbed insulin metabolism in Type I Diabetics leading to delayed puberty, along with overfeeding stimulating early pubertal onset. Additionally, recent clinical trials bred female mice with IR deletions on Kiss1 neurons and observed delayed vaginal opening and estrus. Current animal research suggests low carbohydrate intake may delay pubertal onset, however additional research is required to determine outcome in human subjects. Copyright© of YS Medical Media ltd.

Whey or Casein Hydrolysate with Carbohydrate for Metabolism and Performance in Cycling.

PubMed

Oosthuyse, T; Carstens, M; Millen, A M E

2015-07-01

The protein type most suitable for ingestion during endurance exercise is undefined. This study compared co-ingestion of either 15 g/h whey or casein hydrolysate with 63 g/h fructose: maltodextrin (0.8:1) on exogenous carbohydrate oxidation, exercise metabolism and performance. 2 h postprandial, 8 male cyclists ingested either: carbohydrate-only, carbohydrate-whey hydrolysate, carbohydrate-casein hydrolysate or placebo-water in a crossover, double-blind design during 2 h of exercise at 60%W max followed by a 16-km time trial. Data were evaluated by magnitude-based inferential statistics. Exogenous carbohydrate oxidation, measured from (13)CO2 breath enrichment, was not substantially influenced by co-ingestion of either protein hydrolysate. However, only co-ingestion of carbohydrate-casein hydrolysate substantially decreased (98% very likely decrease) total carbohydrate oxidation (mean±SD, 242±44; 258±47; 277±33 g for carbohydrate-casein, carbohydrate-whey and carbohydrate-only, respectively) and substantially increased (93% likely increase) total fat oxidation (92±14; 83±27; 73±19 g) compared with carbohydrate-only. Furthermore, only carbohydrate-casein hydrolysate ingestion resulted in a faster time trial (-3.6%; 90% CI: ±3.2%) compared with placebo-water (95% likely benefit). However, neither protein hydrolysate enhanced time trial performance when compared with carbohydrate-only. Under the conditions of this study, ingesting carbohydrate-casein, but not carbohydrate-whey hydrolysate, favourably alters metabolism during prolonged moderate-strenuous cycling without substantially altering cycling performance compared with carbohydrate-only. © Georg Thieme Verlag KG Stuttgart · New York.

Surface modification via strain-promoted click reaction facilitates targeted lentiviral transduction.

PubMed

Chu, Yanjie; Oum, Yoon Hyeun; Carrico, Isaac S

2016-01-01

As a result of their ability to integrate into the genome of both dividing and non-dividing cells, lentiviruses have emerged as a promising vector for gene delivery. Targeted gene transduction of specific cells and tissues by lentiviral vectors has been a major goal, which has proven difficult to achieve. We report a novel targeting protocol that relies on the chemoselective attachment of cancer specific ligands to unnatural glycans on lentiviral surfaces. This strategy exhibits minimal perturbation on virus physiology and demonstrates remarkable flexibility. It allows for targeting but can be more broadly useful with applications such as vector purification and immunomodulation. Copyright © 2015 Elsevier Inc. All rights reserved.

Front surface structured targets for enhancing laser-plasma interactions

NASA Astrophysics Data System (ADS)

Snyder, Joseph; George, Kevin; Ji, Liangliang; Yalamanchili, Sasir; Simonoff, Ethan; Cochran, Ginevra; Daskalova, Rebecca; Poole, Patrick; Willis, Christopher; Lewis, Nathan; Schumacher, Douglass

2016-10-01

We present recent progress made using front surface structured interfaces for enhancing ultrashort, relativistic laser-plasma interactions. Structured targets can increase laser absorption and enhance ion acceleration through a number of mechanisms such as direct laser acceleration and laser guiding. We detail experimental results obtained at the Scarlet laser facility on hollow, micron-scale plasma channels for enhancing electron acceleration. These targets show a greater than three times enhancement in the electron cutoff energy as well as an increased slope temperature for the electron distribution when compared to a flat interface. Using three-dimensional particle-in-cell (PIC) simulations, we have modeled the interaction to give insight into the physical processes responsible for the enhancement. Furthermore, we have used PIC simulations to design structures that are more advantageous for ion acceleration. Such targets necessitate advanced target fabrication methods and we describe techniques used to manufacture optimized structures, including vapor-liquid-solid growth, cryogenic etching, and 3D printing using two-photon-polymerization. This material is based upon work supported by the Air Force Office of Scientific Research under Award Number FA9550-14-1-0085.

Focus on Nutrition: Cats and carbohydrates: implications for health and disease.

PubMed

Laflammme, Dottie

2010-01-01

It has been suggested that high-carbohydrate diets contribute to the development of feline diabetes and obesity. The evidence does not support this. Healthy cats efficiently digest and metabolize properly processed starches and complex carbohydrates. Dietary carbohydrate can efficiently meet cats' cellular requirement for carbohydrate (glucose), sparing protein that would otherwise be needed for gluconeogenesis. Excess calories, regardless of source, contribute to obesity and obesity-related problems, but low-carbohydrate, high-fat diets pose a greater risk for obesity. The increasing prevalence of feline diabetes appears to be due to obesity and aging rather than to dietary carbohydrates. However, once cats become diabetic, consumption of a high-protein, low-carbohydrate diet may be beneficial.

Separation of negatively charged carbohydrates by capillary electrophoresis.

PubMed

Linhardt, R J; Pervin, A

1996-01-12

Capillary electrophoresis (CE) has recently emerged as a highly promising technique consuming an extremely small amount of sample and capable of the rapid, high-resolution separation, characterization, and quantitation of analytes. CE has been used for the separation of biopolymers, including acidic carbohydrates. Since CE is basically an analytical method for ions, acidic carbohydrates that give anions in weakly acid, neutral, or alkaline media are often the direct objects of this method. The scope of this review is limited to the use of CE for the analysis of carbohydrates containing carboxylate, sulfate, and phosphate groups as well as neutral carbohydrates that have been derivatized to incorporate strongly acidic functionality, such as sulfonate groups.

Chiral reagents in glycosylation and modification of carbohydrates.

PubMed

Wang, Hao-Yuan; Blaszczyk, Stephanie A; Xiao, Guozhi; Tang, Weiping

2018-02-05

Carbohydrates play a significant role in numerous biological events, and the chemical synthesis of carbohydrates is vital for further studies to understand their various biological functions. Due to the structural complexity of carbohydrates, the stereoselective formation of glycosidic linkages and the site-selective modification of hydroxyl groups are very challenging and at the same time extremely important. In recent years, the rapid development of chiral reagents including both chiral auxiliaries and chiral catalysts has significantly improved the stereoselectivity for glycosylation reactions and the site-selectivity for the modification of carbohydrates. These new tools will greatly facilitate the efficient synthesis of oligosaccharides, polysaccharides, and glycoconjugates. In this tutorial review, we will summarize these advances and highlight the most recent examples.

Carbohydrates and Depression.

ERIC Educational Resources Information Center

Wurtman, Richard J.; Wurtman, Judith J.

1989-01-01

Describes the symptoms, such as appetite change and mood fluctuation, basic mechanisms, and some treatments of Seasonal Affective Disorder (SAD), Carbohydrate-Craving Obesity (CCO) and Premenstrual Syndrome (PMS). Provides several tables and diagrams, and three reading references. (YP)

Carbohydrate and alditol analysis by high-performance anion-exchange chromatography coupled with electrochemical detection at a cobalt-modified electrode.

PubMed

Casella, Innocenzo G; Contursi, Michela

2003-07-01

A cobalt oxyhydroxide film dispersed on a carbon electrode surface was characterized and proposed as an amperometric sensor for determination of alditols and carbohydrates in flowing streams. Complex mixtures of carbohydrates were separated by anion-exchange chromatography using a moderately alkaline solution as mobile phase. The cobalt modified electrode (GC-Co) was employed under a constant applied potential of 0.5 V (vs Ag/AgCl). Under these experimental conditions the detection limits (S/N=3) for all analyzed electroactive molecules ranged between 0.3 micromol L(-1) and 1.5 micromol L(-1) and the dynamic linear ranges spanned generally three orders of magnitude above the relevant detection limits. Analytical determinations of carbohydrates and alditols in red and white wines, are reported.

Degradation properties of protein and carbohydrate during sludge anaerobic digestion.

PubMed

Yang, Guang; Zhang, Panyue; Zhang, Guangming; Wang, Yuanyuan; Yang, Anqi

2015-09-01

Degradation of protein and carbohydrate is vital for sludge anaerobic digestion performance. However, few studies focused on degradation properties of protein and carbohydrate. This study investigated detailed degradation properties of sludge protein and carbohydrate in order to gain insight into organics removal during anaerobic digestion. Results showed that carbohydrate was more efficiently degraded than protein and was degraded prior to protein. The final removal efficiencies of carbohydrate and protein were 49.7% and 32.2%, respectively. The first 3 days were a lag phase for protein degradation since rapid carbohydrate degradation in this phase led to repression of protease formation. Kinetics results showed that, after initial lag phase, protein degradation followed the first-order kinetic with rate constants of 0.0197 and 0.0018 d(-1) during later rapid degradation phase and slow degradation phase, respectively. Carbohydrate degradation also followed the first-order kinetics with a rate constant of 0.007 d(-1) after initial quick degradation phase. Copyright © 2015 Elsevier Ltd. All rights reserved.

Identification of carbohydrate anomers using ion mobility-mass spectrometry.

PubMed

Hofmann, J; Hahm, H S; Seeberger, P H; Pagel, K

2015-10-08

Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

Identification of carbohydrate anomers using ion mobility-mass spectrometry

NASA Astrophysics Data System (ADS)

Hofmann, J.; Hahm, H. S.; Seeberger, P. H.; Pagel, K.

2015-10-01

Carbohydrates are ubiquitous biological polymers that are important in a broad range of biological processes. However, owing to their branched structures and the presence of stereogenic centres at each glycosidic linkage between monomers, carbohydrates are harder to characterize than are peptides and oligonucleotides. Methods such as nuclear magnetic resonance spectroscopy can be used to characterize glycosidic linkages, but this technique requires milligram amounts of material and cannot detect small amounts of coexisting isomers. Mass spectrometry, on the other hand, can provide information on carbohydrate composition and connectivity for even small amounts of sample, but it cannot be used to distinguish between stereoisomers. Here, we demonstrate that ion mobility-mass spectrometry--a method that separates molecules according to their mass, charge, size, and shape--can unambiguously identify carbohydrate linkage-isomers and stereoisomers. We analysed six synthetic carbohydrate isomers that differ in composition, connectivity, or configuration. Our data show that coexisting carbohydrate isomers can be identified, and relative concentrations of the minor isomer as low as 0.1 per cent can be detected. In addition, the analysis is rapid, and requires no derivatization and only small amounts of sample. These results indicate that ion mobility-mass spectrometry is an effective tool for the analysis of complex carbohydrates. This method could have an impact on the field of carbohydrate synthesis similar to that of the advent of high-performance liquid chromatography on the field of peptide assembly in the late 1970s.

Dietary Carbohydrates and Childhood Functional Abdominal Pain.

PubMed

Chumpitazi, Bruno P; Shulman, Robert J

2016-01-01

Childhood functional gastrointestinal disorders (FGIDs) affect a large number of children throughout the world. Carbohydrates (which provide the majority of calories consumed in the Western diet) have been implicated both as culprits for the etiology of symptoms and as potential therapeutic agents (e.g., fiber) in childhood FGIDs. In this review, we detail how carbohydrate malabsorption may cause gastrointestinal symptoms (e.g., bloating) via the physiologic effects of both increased osmotic activity and increased gas production from bacterial fermentation. Several factors may play a role, including: (1) the amount of carbohydrate ingested; (2) whether ingestion is accompanied by a meal or other food; (3) the rate of gastric emptying (how quickly the meal enters the small intestine); (4) small intestinal transit time (the time it takes for a meal to enter the large intestine after first entering the small intestine); (5) whether the meal contains bacteria with enzymes capable of breaking down the carbohydrate; (6) colonic bacterial adaptation to one's diet, and (7) host factors such as the presence or absence of visceral hypersensitivity. By detailing controlled and uncontrolled trials, we describe how there is a general lack of strong evidence supporting restriction of individual carbohydrates (e.g., lactose, fructose) for childhood FGIDs. We review emerging evidence suggesting that a more comprehensive restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) may be effective. Finally, we review how soluble fiber (a complex carbohydrate) supplementation via randomized controlled intervention trials in childhood functional gastrointestinal disorders has demonstrated efficacy. © 2016 S. Karger AG, Basel.

E-selectin liposomal and nanotube-targeted delivery of doxorubicin to circulating tumor cells

PubMed Central

Mitchell, Michael J.; Chen, Christina S.; Ponmudi, Varun; Hughes, Andrew D.; King, Michael R.

2012-01-01

The presence of circulating tumor cells (CTCs) is believed to lead to the formation of secondary tumors via an adhesion cascade involving interaction between adhesion receptors of endothelial cells and ligands on CTCs. Many CTCs express sialylated carbohydrate ligands on their surfaces that adhere to selectin protein found on inflamed endothelial cells. We have investigated the feasibility of using immobilized selectin proteins as a targeting mechanism for CTCs under flow. Herein, targeted liposomal doxorubicin (L-DXR) was functionalized with recombinant human E-selectin (ES) and polyethylene glycol (PEG) to target and kill cancer cells under shear flow, both when immobilized along a microtube device or sheared in a cone-and-plate viscometer in a dilute suspension. Healthy circulating cells such as red blood cells were not targeted by this mechanism and were left to freely circulate, and minimal leukocyte death was observed. Halloysite nanotube (HNT)-coated microtube devices immobilized with nanoscale liposomes significantly enhanced the targeting, capture, and killing of cancer cells. This work demonstrates that E-selectin functionalized L-DXR, sheared in suspension or immobilized onto microtube devices, provides a novel approach to selectively target and deliver chemotherapeutics to CTCs in the bloodstream. PMID:22421423

Pyrrolic tripodal receptors for carbohydrates. Role of functional groups and binding geometry on carbohydrate recognition.

PubMed

Cacciarini, Martina; Nativi, Cristina; Norcini, Martina; Staderini, Samuele; Francesconi, Oscar; Roelens, Stefano

2011-02-21

The contribution from several H-bonding groups and the impact of geometric requirements on the binding ability of benzene-based tripodal receptors toward carbohydrates have been investigated by measuring the affinity of a set of structures toward octyl β-D-glucopyranoside, selected as a representative monosaccharide. The results reported in the present study demonstrate that a judicious choice of correct geometry and appropriate functional groups is critical to achieve the complementary hydrogen bonding interactions required for an effective carbohydrate recognition.

Absorption patterns of meals containing complex carbohydrates in type 1 diabetes.

PubMed

Elleri, D; Allen, J M; Harris, J; Kumareswaran, K; Nodale, M; Leelarathna, L; Acerini, C L; Haidar, A; Wilinska, M E; Jackson, N; Umpleby, A M; Evans, M L; Dunger, D B; Hovorka, R

2013-05-01

Successful postprandial glycaemia management requires understanding of absorption patterns after meals containing variable complex carbohydrates. We studied eight young participants with type 1 diabetes to investigate a large low-glycaemic-load (LG) meal and another eight participants to investigate a high-glycaemic-load (HG) meal matched for carbohydrates (121 g). On Visit 1, participants consumed an evening meal. On follow-up Visit 2, a variable-target glucose clamp was performed to reproduce glucose and insulin levels from Visit 1. Adopting stable-label tracer dilution methodology, we measured endogenous glucose production on Visit 2 and subtracted it from total glucose appearance measured on Visit 1 to obtain meal-attributable glucose appearance. After the LG meal, 25%, 50% and 75% of cumulative glucose appearance was at 88 ± 21, 175 ± 39 and 270 ± 54 min (mean ± SD), whereas glucose from the HG meal appeared significantly faster at 56 ± 12, 100 ± 25 and 153 ± 39 min (p < 0.001 to 0.003), and resulted in a 50% higher peak appearance (p < 0.001). Higher apparent bioavailability by 15% (p = 0.037) was observed after the LG meal. We documented a 20 min deceleration of dietary mixed carbohydrates compared with dietary glucose for the HG meal and a twofold deceleration for the LG meal. Absorption patterns may be influenced by glycaemic load and/or meal composition, affecting optimum prandial insulin dosing in type 1 diabetes.

Carbohydrate intake and tennis: are there benefits?

PubMed Central

Kovacs, M S

2006-01-01

Carbohydrate supplementation in prolonged aerobic exercise has been shown to be effective in improving performance and deferring fatigue. However, there is confounding evidence with regard to carbohydrate supplementation and tennis performance, which may be due to the limited number of studies on this topic. This evidence based review, using database searches of Medline and SPORTDiscus, summarises the limited relevant literature to determine if carbohydrate supplementation benefits tennis performance, and, if so, the appropriate amounts and timing. Although more research is required, it appears that it may be beneficial in tennis sessions lasting more than 90 minutes. PMID:16632561

pdb-care (PDB carbohydrate residue check): a program to support annotation of complex carbohydrate structures in PDB files.

PubMed

Lütteke, Thomas; von der Lieth, Claus-W

2004-06-04

Carbohydrates are involved in a variety of fundamental biological processes and pathological situations. They therefore have a large pharmaceutical and diagnostic potential. Knowledge of the 3D structure of glycans is a prerequisite for a complete understanding of their biological functions. The largest source of biomolecular 3D structures is the Protein Data Bank. However, about 30% of all 1663 PDB entries (version September 2003) containing carbohydrates comprise errors in glycan description. Unfortunately, no software is currently available which aligns the 3D information with the reported assignments. It is the aim of this work to fill this gap. The pdb-care program http://www.glycosciences.de/tools/pdb-care/ is able to identify and assign carbohydrate structures using only atom types and their 3D atom coordinates given in PDB-files. Looking up a translation table where systematic names and the respective PDB residue codes are listed, both assignments are compared and inconsistencies are reported. Additionally, the reliability of reported and calculated connectivities for molecules listed within the HETATOM records is checked and unusual values are reported. Frequent use of pdb-care will help to improve the quality of carbohydrate data contained in the PDB. Automatic assignment of carbohydrate structures contained in PDB entries will enable the cross-linking of glycobiology resources with genomic and proteomic data collections.

Binding of Human GII.4 Norovirus Virus-Like Particles to Carbohydrates of Romaine Lettuce Leaf Cell Wall Materials

PubMed Central

Esseili, Malak A.

2012-01-01

Norovirus (NoV) genogroup II genotype 4 (GII.4) strains are the dominant cause of the majority of food-borne outbreaks, including those that involve leafy greens, such as lettuce. Since human NoVs use carbohydrates of histo-blood group antigens as receptors/coreceptors, we examined the role of carbohydrates in the attachment of NoV to lettuce leaves by using virus-like particles (VLPs) of a human NoV/GII.4 strain. Immunofluorescence analysis showed that the VLPs attached to the leaf surface, especially to cut edges, stomata, and along minor veins. Binding was quantified using enzyme-linked immunosorbent assay (ELISA) performed on cell wall materials (CWM) from innermost younger leaves and outermost lamina of older leaves. The binding to CWM of older leaves was significantly (P < 0.05) higher (1.5- to 2-fold) than that to CWM of younger leaves. Disrupting the carbohydrates of CWM or porcine gastric mucin (PGM) (a carbohydrate control) using 100 mM sodium periodate (NaIO4) significantly decreased the binding an average of 17% in younger leaves, 43% in older leaves, and 92% for PGM. In addition, lectins recognizing GalNAc, GlcNAc, and sialic acid at 100 μg/ml significantly decreased the binding an average of 41%, 33%, and 20% on CWM of older leaves but had no effect on younger leaves. Lectins recognizing α-d-Gal, α-d-Man/α-d-Glc, and α-l-Fuc showed significant inhibition on CWM of older leaves as well as that of younger leaves. All lectins, except for the lectin recognizing α-d-Gal, significantly inhibited NoV VLP binding to PGM. Collectively, our results indicate that NoV VLPs bind to lettuce CWM by utilizing multiple carbohydrate moieties. This binding may enhance virus persistence on the leaf surface and prevent effective decontamination. PMID:22138991

Influence on bone metabolism of dietary trace elements, protein, fat, carbohydrates, and vitamins.

PubMed

Sarazin, M; Alexandre, C; Thomas, T

2000-01-01

Osteoporosis is a multifactorial disease driven primarily by the genetic factors that control bone metabolism. Among environmental factors, diet may play a key role, affording a target for low-cost intervention. Calcium and vitamin D are well known to affect bone metabolism. Other nutrients may influence bone mass changes; for instance, a number of trace elements and vitamins other than vitamin D are essential to many of the steps of bone metabolism. A wide variety of foods provide these nutrients, and in industrialized countries deficiencies are more often due to idiosyncratic eating habits than to cultural influences. Both culture and vogue influence the amount of carbohydrate, fat, and protein in the typical diet. In children, the current trend is to reduce protein and to increase carbohydrate and fat. Data from epidemiological and animal studies suggest that this may adversely affect bone mass and the fracture risk.

Complex carbohydrates (image)

MedlinePlus

... Glucose is used in the cells of the body and in the brain. Any unused glucose is stored in the liver and muscles as glycogen for use later. Complex carbohydrate foods provide vitamins, minerals, and fiber that are important to the ...

Carbohydrate CuAAC click chemistry for therapy and diagnosis.

PubMed

He, Xiao-Peng; Zeng, Ya-Li; Zang, Yi; Li, Jia; Field, Robert A; Chen, Guo-Rong

2016-06-24

Carbohydrates are important as signaling molecules and for cellular recognition events, therefore offering scope for the development of carbohydrate-mimetic diagnostics and drug candidates. As a consequence, the construction of carbohydrate-based bioactive compounds and sensors has become an active research area. While the advent of click chemistry has greatly accelerated the progress of medicinal chemistry and chemical biology, recent literature has seen an extensive use of such approaches to construct functionally diverse carbohydrate derivatives. Here we summarize some of the progress, covering the period 2010 to mid-2015, in Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition CuAAC "click chemistry" of carbohydrate derivatives, in the context of potential therapeutic and diagnostic tool development. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Indium Triflate Catalyzed Peracetylation of Carbohydrates

PubMed Central

Bizier, Nicholas P.; Atkins, Shannon R.; Helland, Luke C.; Colvin, Shane F.; Twitchell, Joseph R.; Cloninger, Mary J.

2008-01-01

Peracetylation is a very common protection strategy that is widely implemented in carbohydrate synthesis. Here, a method for peracetylation of carbohydrates using catalytic In(OTf)3 in neat acetic anhydride is reported. In(OTf)3 has low toxicity and is mild and water tolerant, and the reactions are high yielding and efficient. Details regarding the scope and mechanism of the reaction are briefly discussed. PMID:18440500

Metabolic response to high-carbohydrate and low-carbohydrate meals in a nonhuman primate model.

PubMed

Fabbrini, Elisa; Higgins, Paul B; Magkos, Faidon; Bastarrachea, Raul A; Voruganti, V Saroja; Comuzzie, Anthony G; Shade, Robert E; Gastaldelli, Amalia; Horton, Jay D; Omodei, Daniela; Patterson, Bruce W; Klein, Samuel

2013-02-15

We established a model of chronic portal vein catheterization in an awake nonhuman primate to provide a comprehensive evaluation of the metabolic response to low-carbohydrate/high-fat (LCHF; 20% carbohydrate and 65% fat) and high-carbohydrate/low-fat (HCLF; 65% carbohydrate and 20% fat) meal ingestion. Each meal was given 1 wk apart to five young adult (7.8 ± 1.3 yr old) male baboons. A [U-¹³C]glucose tracer was added to the meal, and a [6,6-²H₂]glucose tracer was infused systemically to assess glucose kinetics. Plasma areas under the curve (AUCs) of glucose, insulin, and C-peptide in the femoral artery and of glucose and insulin in the portal vein were higher (P ≤ 0.05) after ingestion of the HCLF compared with the LCHF meal. Compared with the LCHF meal, the rate of appearance of ingested glucose into the portal vein and the systemic circulation was greater after the HCLF meal (P < 0.05). Endogenous glucose production decreased by ∼40% after ingestion of the HCLF meal but was not affected by the LCHF meal (P < 0.05). Portal vein blood flow increased (P < 0.001) to a similar extent after consumption of either meal. In conclusion, a LCHF diet causes minimal changes in the rate of glucose appearance in both portal and systemic circulations, does not affect the rate of endogenous glucose production, and causes minimal stimulation of C-peptide and insulin. These observations demonstrate that LCHF diets cause minimal perturbations in glucose homeostasis and pancreatic β-cell activity.

Structural features facilitating tumor cell targeting and internalization by bleomycin and its disaccharide.

PubMed

Yu, Zhiqiang; Paul, Rakesh; Bhattacharya, Chandrabali; Bozeman, Trevor C; Rishel, Michael J; Hecht, Sidney M

2015-05-19

We have shown previously that the bleomycin (BLM) carbohydrate moiety can recapitulate the tumor cell targeting effects of the entire BLM molecule, that BLM itself is modular in nature consisting of a DNA-cleaving aglycone which is delivered selectively to the interior of tumor cells by its carbohydrate moiety, and that there are disaccharides structurally related to the BLM disaccharide which are more efficient than the natural disaccharide at tumor cell targeting/uptake. Because BLM sugars can deliver molecular cargoes selectively to tumor cells, and thus potentially form the basis for a novel antitumor strategy, it seemed important to consider additional structural features capable of affecting the efficiency of tumor cell recognition and delivery. These included the effects of sugar polyvalency and net charge (at physiological pH) on tumor cell recognition, internalization, and trafficking. Since these parameters have been shown to affect cell surface recognition, internalization, and distribution in other contexts, this study has sought to define the effects of these structural features on tumor cell recognition by bleomycin and its disaccharide. We demonstrate that both can have a significant effect on tumor cell binding/internalization, and present data which suggests that the metal ions normally bound by bleomycin following clinical administration may significantly contribute to the efficiency of tumor cell uptake, in addition to their characterized function in DNA cleavage. A BLM disaccharide-Cy5** conjugate incorporating the positively charged dipeptide d-Lys-d-Lys was found to associate with both the mitochondria and the nuclear envelope of DU145 cells, suggesting possible cellular targets for BLM disaccharide-cytotoxin conjugates.

Synthetic Methods for Ester Bond Formation and Conformational Analysis of Ester-Containing Carbohydrates

NASA Astrophysics Data System (ADS)

Hackbusch, Sven

carbohydrate based compounds with specific shape constraints for its use as enzyme inhibitors or similar targets. In addition, the above project led to the development of a methodology for the synthesis of symmetrical ester molecules from primary alcohols using a mild oxidative esterification reaction, which proceeds in hydrous solvents using a nitrosyl radical catalyst. The reaction could be performed with a variety of alcohols and the resulting compounds are of interest in the fragrance and flavor industries.

Characterization of Protein-Carbohydrate Interactions by NMR Spectroscopy.

PubMed

Grondin, Julie M; Langelaan, David N; Smith, Steven P

2017-01-01

Solution-state nuclear magnetic resonance (NMR) spectroscopy can be used to monitor protein-carbohydrate interactions. Two-dimensional 1 H- 15 N heteronuclear single quantum coherence (HSQC)-based techniques described in this chapter can be used quickly and effectively to screen a set of possible carbohydrate binding partners, to quantify the dissociation constant (K d ) of any identified interactions, and to map the carbohydrate binding site on the structure of the protein. Here, we describe the titration of a family 32 carbohydrate binding module from Clostridium perfringens (CpCBM32) with the monosaccharide N-acetylgalactosamine (GalNAc), in which we calculate the apparent dissociation of the interaction, and map the GalNAc binding site onto the structure of CpCBM32.

Computational carbohydrate chemistry: what theoretical methods can tell us

PubMed Central

Woods, Robert J.

2014-01-01

Computational methods have had a long history of application to carbohydrate systems and their development in this regard is discussed. The conformational analysis of carbohydrates differs in several ways from that of other biomolecules. Many glycans appear to exhibit numerous conformations coexisting in solution at room temperature and a conformational analysis of a carbohydrate must address both spatial and temporal properties. When solution nuclear magnetic resonance data are used for comparison, the simulation must give rise to ensemble-averaged properties. In contrast, when comparing to experimental data obtained from crystal structures a simulation of a crystal lattice, rather than of an isolated molecule, is appropriate. Molecular dynamics simulations are well suited for such condensed phase modeling. Interactions between carbohydrates and other biological macromolecules are also amenable to computational approaches. Having obtained a three-dimensional structure of the receptor protein, it is possible to model with accuracy the conformation of the carbohydrate in the complex. An example of the application of free energy perturbation simulations to the prediction of carbohydrate-protein binding energies is presented. PMID:9579797

High Carbohydrate-Fiber Nutrition for Running and Health.

ERIC Educational Resources Information Center

Battinelli, Thomas

1983-01-01

The roles of carbohydrates, fats, proteins, and fiber in producing energy for health and exercise are discussed. Long-distance runners should have a high intake of complex carbohydrates and fiber. (PP)

Role of preoperative carbohydrate loading: a systematic review.

PubMed

Bilku, D K; Dennison, A R; Hall, T C; Metcalfe, M S; Garcea, G

2014-01-01

Surgical stress in the presence of fasting worsens the catabolic state, causes insulin resistance and may delay recovery. Carbohydrate rich drinks given preoperatively may ameliorate these deleterious effects. A systematic review was undertaken to analyse the effect of preoperative carbohydrate loading on insulin resistance, gastric emptying, gastric acidity, patient wellbeing, immunity and nutrition following surgery. All studies identified through PubMed until September 2011 were included. References were cross-checked to ensure capture of cited pertinent articles. Overall, 17 randomised controlled trials with a total of 1,445 patients who met the inclusion criteria were identified. Preoperative carbohydrate drinks significantly improved insulin resistance and indices of patient comfort following surgery, especially hunger, thirst, malaise, anxiety and nausea. No definite conclusions could be made regarding preservation of muscle mass. Following ingestion of carbohydrate drinks, no adverse events such as apparent or proven aspiration during or after surgery were reported. Administration of oral carbohydrate drinks before surgery is probably safe and may have a positive influence on a wide range of perioperative markers of clinical outcome. Further studies are required to determine its cost effectiveness.

Targeting Host Cell Surface Nucleolin for RSV Therapy: Challenges and Opportunities.

PubMed

Mastrangelo, Peter; Norris, Michael J; Duan, Wenming; Barrett, Edward G; Moraes, Theo J; Hegele, Richard G

2017-09-19

Nucleolin (NCL) has been reported as a cellular receptor for the human respiratory syncytial virus (RSV). We studied the effects of re-purposing AS1411, an anti-cancer compound that binds cell surface NCL, as a possible novel strategy for RSV therapy in vitro and in vivo. AS1411 was administered to RSV-infected cultures of non-polarized (HEp-2) and polarized (MDCK) epithelial cells and to virus-infected mice and cotton rats. Results of in vitro experiments showed that AS1411, used in micromolar concentrations, was associated with decreases in the number of virus-positive cells. Intranasal administration of AS1411 (50 mg/kg) to RSV-infected mice and cotton rats was associated with partial reductions in lung viral titers, decreased virus-associated airway inflammation, and decreased IL-4/IFN-γ ratios when compared to untreated, infected animals. In conclusion, our findings indicate that therapeutic use of AS1411 has modest effects on RSV replication and host response. While the results underscore the challenges of targeting cell surface NCL as a potential novel strategy for RSV therapy, they also highlight the potential of cell surface NCL as a therapeutic target.

Rapid synthesis of carbohydrate derivatives, including mimetics of C-linked disaccharides and C-linked aza disaccharides, using the hetero-Diels-Alder reaction.

PubMed

Burland, Peter A; Coisson, David; Osborn, Helen M I

2010-11-05

In this work we demonstrate the value of performing a hetero-Diels-Alder reaction (HDAR) between Danishefsky's diene and a range of aldehydes or imines, under microwave irradiation. By using a range of aldehydes and imines, including those derived from carbohydrates, access to functionalized 2,3-dihydro-4H-pyran-4-ones or 2,3-dihydro-4-pyridinones in good to excellent synthetic yields is possible. A particular strength of the methodology is its ability to access mimetics of C-linked disaccharides and C-linked aza disaccharides, targets of current therapeutic interest, in a rapid, convenient, and diastereoselective manner. The effect of high pressure on the HDARs involving carbohydrate-derived aldehydes and imines is also explored, with enhancement in yields occurring for the aldehyde substrates. Finally, HDARs using carbohydrate derived ketones, enones, and enals are described under a range of conditions. Optimum results were obtained under high-pressure conditions, with highly functionalized carbohydrate derivatives being afforded, in good yields, in this way.

Carbohydrate Analysis: Can We Control the Ripening of Bananas?

NASA Astrophysics Data System (ADS)

Deal, S. Todd; Farmer, Catherine E.; Cerpovicz, Paul F.

2002-04-01

We have developed an experiment for nutritional/introductory biochemistry courses that focuses on carbohydrate analysis--specifically, the carbohydrates found in bananas and the change in carbohydrate composition as the banana ripens. Pairs of students analyze the starch and reducing sugar content of green, ripe, and overripe bananas. Using the techniques and knowledge gained from these analyses, they then investigate the influence of various storage methods on the ripening process. While this experiment was developed for an introductory-level biochemistry lab, it can easily be adapted for use in other laboratory programs that seek to teach the fundamentals of carbohydrate analysis.

Carbohydrate phenotyping of human and animal milk glycoproteins.

PubMed

Gustafsson, Anki; Kacskovics, Imre; Breimer, Michael E; Hammarström, Lennart; Holgersson, Jan

2005-03-01

Breast-milk has a well-known anti-microbial effect, which is in part due to the many different carbohydrate structures expressed. This renders it a position as a potential therapeutic for treatment of infection by different pathogens, thus avoiding the drawbacks of many antibiotics. The plethora of carbohydrate epitopes in breast-milk is known to differ between species, with human milk expressing the most complex one. We have investigated the expression of protein-bound carbohydrate epitopes in milk from man, cow, goat, sheep, pig, horse, dromedary and rabbit. Proteins were separated by SDS-PAGE and the presence of carbohydrate epitopes on milk proteins were analysed by Western blotting using different lectins and carbohydrate-specific antibodies. We show that ABH, Lewis (Le)x, sialyl-Lex, Lea, sialyl-Lea and Leb carbohydrate epitopes are expressed mainly on man, pig and horse milk proteins. The blood group precursor structure H type 1 is expressed in all species investigated, while only pig, dromedary and rabbit milk proteins carry H type 2 epitopes. These epitopes are receptors for Helicobacter pylori (Leb and sialyl-Lex), enteropathogenic (H type 1, Lea and Lex) and enterotoxic Escherichia coli (heat-stable toxin; H type 1 and 2), and Campylobacter jejuni (H type 2). Thus, milk from these animals or their genetically modified descendants could have a therapeutic effect by inhibiting pathogen colonization and infection.

Ulex europaeus 1 lectin targets microspheres to mouse Peyer's patch M-cells in vivo.

PubMed

Foster, N; Clark, M A; Jepson, M A; Hirst, B H

1998-03-01

The interaction of latex microspheres with mouse Peyer's patch membranous M-cells was studied in a mouse gut loop model after the microspheres were coated with a variety of agents. Carboxylated microspheres (diameter 0.5 micron) were covalently coated with lectins Ulex europaeus 1, Concanavalin A, Euonymus europaeus and Bandeiraea simplicifolia 1 isolectin-B4, human immunoglobulin A or bovine serum albumin. Of the treatments examined, only Ulex europaeus (UEA1) resulted in significant selective binding of microspheres to M-cells. UEA1-coated microspheres bound to M-cells at a level 100-fold greater than BSA-coated microspheres, but binding to enterocytes was unaffected. Incubation of UEA1-coated microspheres with alpha-L-fucose reduced M-cell binding to a level comparable with BSA-coated microspheres. This indicated that targeting by UEA1 was via a carbohydrate receptor on the M-cell surface. Adherence of UEA1-coated microspheres to M-cells occurred within 10 min of inoculation into mouse gut loops and UEA1-coated microspheres were transported to 10 microns below the apical surface of M-cells within 60 min of inoculation. UEA1-coated microspheres also targeted mouse Peyer's patch M-cells after intragastric administration. These results demonstrated that altering the surface chemistry of carboxylated polystyrene microspheres increased M-cell targeting, suggesting a strategy to enhance delivery of vaccine antigens to the mucosal immune system.

Baroreflex sensitivity in acute hypoxia and carbohydrate loading.

PubMed

Klemenc, Matjaž; Golja, Petra

2011-10-01

Hypoxia decreases baroreflex sensitivity (BRS) and can be a sufficient cause for syncope in healthy individuals. Carbohydrate loading enhances efferent sympathetic activity, which affects cardiac contractility, heart rate and vascular resistance, the main determinants of blood pressure. Thus, in both normoxia and hypoxia, carbohydrate loading may be more than simply metabolically beneficial, as it may affect blood pressure regulation. We hypothesised that carbohydrate loading will, in both normoxia and hypoxia, alter the regulation of blood pressure, as reflected in a change in baroreflex sensitivity. Fourteen subjects participated in two experiments, composed of a 15-min normoxic period, after which the subjects ingested water or an equal amount of water with carbohydrates. A 30-min rest period was then followed by a 10-min second normoxic and a 30-min hypoxic period. Blood pressure and heart rate were monitored continuously during the experiment to determine BRS. Despite an increased sympathetic activation, reflected in increased heart rate (P < 0.001) BRS was lower (P < 0.01) after carbohydrate loading, as compared to the water experiment, in both normoxic [23.7 (12.4) versus 28.8 (13.8) ms/mmHg] and hypoxic [16.8 (11.0) versus 24.3 (12.3) ms/mmHg] phases of the present study. As BRS was decreased in acute hypoxic exposure, the results confirm that hypoxia interferes with blood pressure regulation. However, although oral carbohydrate loading induced sympathoexcitation, it did not improve blood pressure regulation in hypoxia, as evident from the BRS data. Baroreflex effects of other forms of carbohydrate loading, not causing postprandial blood shifts to digestive system, should therefore be investigated.

Mucin- and carbohydrate-stimulated adhesion and subproteome changes of the probiotic bacterium Lactobacillus acidophilus NCFM.

PubMed

Celebioglu, Hasan Ufuk; Olesen, Sita Vaag; Prehn, Kennie; Lahtinen, Sampo J; Brix, Susanne; Abou Hachem, Maher; Svensson, Birte

2017-06-23

Adhesion to intestinal mucosa is a crucial property for probiotic bacteria. Adhesion is thought to increase host-bacterial interactions, thus potentially enabling health benefits to the host. Molecular events connected with adhesion and surface proteome changes were investigated for the probiotic Lactobacillus acidophilus NCFM cultured with established or emerging prebiotic carbohydrates as carbon source and in the presence of mucin, the glycoprotein of the epithelial mucus layer. Variation in adhesion to HT29-cells and mucin was associated with carbon source and mucin-induced subproteome abundancy differences. Specifically, while growth on fructooligosaccharides (FOS) only stimulated adhesion to intestinal HT-29 cells, cellobiose and polydextrose in addition increased adhesion to mucin. Adhesion to HT-29 cells increased by about 2-fold for bacteria grown on mucin-supplemented glucose. Comparative 2DE-MS surface proteome analysis showed different proteins in energy metabolism appearing on the surface, suggesting they exert moonlighting functions. Mucin-supplemented bacteria had relative abundance of pyruvate kinase and fructose-bisphosphate aldolase increased by about 2-fold while six spots with 3.2-2.1 fold reduced relative abundance comprised elongation factor G, phosphoglycerate kinase, BipAEFTU family GTP-binding protein, ribonucleoside triphosphate reductase, adenylosuccinate synthetase, 30S ribosomal protein S1, and manganese-dependent inorganic pyrophosphatase. Surface proteome of cellobiose- compared to glucose-grown L. acidophilus NCFM had phosphate starvation inducible protein stress-related, thermostable pullulanase, and elongation factor G increasing 4.4-2.4 fold, while GAPDH, elongation factor Ts, and pyruvate kinase were reduced by 2.0-1.5 fold in relative abundance. Addition of recombinant L. acidophilus NCFM elongation factor G and pyruvate kinase to a coated mucin layer significantly suppressed subsequent adhesion of the bacterium. Human diet is

Hepatocyte heterogeneity in the metabolism of carbohydrates.

PubMed

Jungermann, K; Thurman, R G

1992-01-01

Periportal and perivenous hepatocytes possess different amounts and activities of the rate-generating enzymes of carbohydrate and oxidative energy metabolism and thus different metabolic capacities. This is the basis of the model of metabolic zonation, according to which periportal cells catalyze predominantly the oxidative catabolism of fatty and amino acids as well as glucose release and glycogen formation via gluconeogenesis, and perivenous cells carry out preferentially glucose uptake for glycogen synthesis and glycolysis coupled to liponeogenesis. The input of humoral and nervous signals into the periportal and perivenous zones is different; gradients of oxygen, substrates and products, hormones and mediators and nerve densities exist which are important not only for the short-term regulation of carbohydrate metabolism but also for the long-term regulation of zonal gene expression. The specialization of periportal and perivenous hepatocytes in carbohydrate metabolism has been well characterized. In vivo evidence is provided by the complex metabolic situation termed the 'glucose paradox' and by zonal flux differences calculated on the basis of the distribution of enzymes and metabolites. In vitro evidence is given by the different flux rates determined with classical invasive techniques, e.g. in periportal-like and perivenous-like hepatocytes in cell culture, in periportal- and perivenous-enriched hepatocyte populations and in perfused livers during orthograde and retrograde flow, as well as with noninvasive techniques using miniature oxygen electrodes, e.g. in livers perfused in either direction. Differences of opinion in the interpretation of studies with invasive and noninvasive techniques by the authors are discussed. The declining gradient in oxygen concentrations, the decreasing glucagon/insulin ratio and the different innervation could be important factors in the zonal expression of the genes of carbohydrate-metabolizing enzymes. While it is clear that

[Sources of dissolved organic carbon and the bioavailability of dissolved carbohydrates in the tributaries of Lake Taihu].

PubMed

Ye, Lin-Lin; Wu, Xiao-Dong; Kong, Fan-Xiang; Liu, Bo; Yan, De-Zhi

2015-03-01

Surface water samples of Yincungang and Chendonggang Rivers were collected from September 2012 to August 2013 in Lake Taihu. Water temperature, Chlorophyll a and bacterial abundance were analyzed, as well as dissolved organic carbon (DOC) concentrations, stable carbon isotope of DOC (Δ13C(DOC)), specific UV absorbance (SUVA254 ) and dissolved carbohydrates concentrations. Δ13C(DOC) ranged from -27.03% per thousand ± 0.30% per thousand to -23.38%per thousand ± 0.20% per thousand, indicating a terrestrial source. Both the autochthonous and allochthonous sources contributed to the carbohydrates pool in the tributaries. Significant differences in PCHO (polysaccharides) and MCHO (monosaccharides) concentrations were observed between spring-summer and autumn-winter (P < 0.01, n = 12; P < 0.01, n = 12), which might be caused by the variation in the sources and bioavailability of carbohydrates. PCHO contributed a major fraction to TCHO (total dissolved carbohydrates) in autumn and winter, which could be explained by the accumulation of undegradable PCHO limited by the low water temperature; MCHO contributed a major fraction to TCHO in spring and summer, which might be caused by the transformation from PCHO by microbes at high water temperature.

Specific intermolecular interactions of conserved water molecules with amino acids in the Galectin-1 carbohydrate recognition domain

NASA Astrophysics Data System (ADS)

Di Lella, Santiago; Petruk, Ariel A.; Armiño, Diego J. Alonso de; Álvarez, Rosa M. S.

2010-08-01

Water molecules, rigidly associated to protein surfaces, play a key role in stabilizing biomolecules and participating in their biological functions. Recent studies on the solvation properties of the carbohydrate recognition domain of Galectin-1 by means of molecular dynamic simulations have revealed the existence of several water sites which were well correlated to both the bound water molecules observed in the crystal structure of the protein in the free state and to some of the hydroxyl groups of the carbohydrate ligand observed in the crystal structure of the complexed protein. In this work, we present a study using quantum mechanical methods (B3LYP/6-311++G(3df,3dp)//B3LYP/6-31+G(d)) to determine the energy involved in the binding of these water molecules to specific amino acids in the carbohydrate recognition domain of the protein. By modeling the hydroxyl groups of the carbohydrate by methanol, the energies associated to the local interactions between the ligand and the protein have been evaluated by replacing specific water molecules with methanol. The values of the binding energies have been compared to those previously obtained by the molecular dynamic method.

Meal frequency of pre-exercise carbohydrate feedings.

PubMed

Chryssanthopoulos, C; Petridou, A; Maridaki, M; Mougios, V

2008-04-01

This study compared the effect of single and multiple carbohydrate feedings before exercise on biochemical and physiological responses during exercise. Eight males performed 3 runs for 1 h at 70 % VO(2max) after consuming a meal containing 2.5 g carbohydrate per kg body mass in a single dose 3 h before exercise (SF), the same meal in 5 equal doses at 3, 2.5, 2, 1.5, and 1 h before exercise (MF), or a liquid placebo 3 h before exercise (P). RER and carbohydrate oxidation rates were higher in SF and MF compared to P trials, but there was no difference between SF and MF trials. Pre-exercise insulin was 2.0- and 3.4- fold higher in SF and MF, respectively, compared to P, and 1.7-fold higher in MF compared to SF. Glycerol and NEFA were higher in P compared to SF and MF trials before and at the end of exercise. In conclusion, a carbohydrate meal containing 2.5 g . kg(-1) ingested in doses over 3 h before running produced higher hyperinsulinemia pre-exercise than that produced when the meal was consumed in a single dose. Nevertheless, estimated carbohydrate utilization and adipose tissue lipolysis during exercise after multiple feedings seemed to be as high as after a single feeding.

Preventing exercise-induced hypoglycemia in type 1 diabetes using real-time continuous glucose monitoring and a new carbohydrate intake algorithm: an observational field study.

PubMed

Riddell, Michael C; Milliken, Jill

2011-08-01

Real-time (RT) continuous glucose monitoring (CGM) offers the possibility to better manage glucose levels during exercise in active individuals with type 1 diabetes mellitus (T1DM). However, studies have yet to determine the appropriate actions to take when glucose levels are trending toward hypoglycemia. The purpose of this observational field study was to test the effectiveness of RT-GCM and a new carbohydrate intake algorithm designed for maintaining euglycemia during sports. During a 2-week sports camp, 25 adolescents (8-17 years old) with T1DM were fitted with a RT-CGM device and instructed to ingest fast-acting carbohydrates (8-20 g, depending on the concentration of glucose at the time of RT-CGM alert and rates of change in glycemia) when glucose levels were trending toward hypoglycemia. Rates of change in glucose were measured before and after algorithm use, and the incidence of hypoglycemia was documented. With RT-CGM and algorithm use, euglycemia was largely maintained with modest amounts of carbohydrate intake, even when glucose levels were initially dropping at an elevated rate (>0.55 mmol/L per 5 min). Mild biochemical hypoglycemia (3.0-3.9 mmol/L) occurred just twice out of 22 uses of the algorithm (9%) when trend arrows alerted the subjects that glucose levels were dropping. When glucose levels were already below target (<5.0 mmol/L), mild hypoglycemia occurred five times out of 13 events (38%), despite 16 g of carbohydrate being ingested. Average glucose levels during sports in the 60 min following algorithm use were 5.8 ± 1.2 mmol/L, 5.3 ± 1.0 mmol/L, and 6.2 ± 0.8 mmol/L in the 20-, 16-, and 8-g carbohydrate intake protocols when glucose levels were initially on target but dropping toward hypoglycemia. When coupled with RT-CGM, a new carbohydrate intake algorithm prevents hypoglycemia and maintains euglycemia during exercise, particularly if patients ingest carbohydrate when trend arrows alert them of a drop in glycemia.

The case for low carbohydrate diets in diabetes management.

PubMed

Arora, Surender K; McFarlane, Samy I

2005-07-14

A low fat, high carbohydrate diet in combination with regular exercise is the traditional recommendation for treating diabetes. Compliance with these lifestyle modifications is less than satisfactory, however, and a high carbohydrate diet raises postprandial plasma glucose and insulin secretion, thereby increasing risk of CVD, hypertension, dyslipidemia, obesity and diabetes. Moreover, the current epidemic of diabetes and obesity has been, over the past three decades, accompanied by a significant decrease in fat consumption and an increase in carbohydrate consumption. This apparent failure of the traditional diet, from a public health point of view, indicates that alternative dietary approaches are needed. Because carbohydrate is the major secretagogue of insulin, some form of carbohydrate restriction is a prima facie candidate for dietary control of diabetes. Evidence from various randomized controlled trials in recent years has convinced us that such diets are safe and effective, at least in short-term. These data show low carbohydrate diets to be comparable or better than traditional low fat high carbohydrate diets for weight reduction, improvement in the dyslipidemia of diabetes and metabolic syndrome as well as control of blood pressure, postprandial glycemia and insulin secretion. Furthermore, the ability of low carbohydrate diets to reduce triglycerides and to increase HDL is of particular importance. Resistance to such strategies has been due, in part, to equating it with the popular Atkins diet. However, there are many variations and room for individual physician planning. Some form of low carbohydrate diet, in combination with exercise, is a viable option for patients with diabetes. However, the extreme reduction of carbohydrate of popular diets (<30 g/day) cannot be recommended for a diabetic population at this time without further study. On the other hand, the dire objections continually raised in the literature appear to have very little scientific

33 CFR 334.200 - Chesapeake Bay, Point Lookout to Cedar Point; aerial and surface firing range and target area, U...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Cedar Point; aerial and surface firing range and target area, U.S. Naval Air Station, Patuxent River... Chesapeake Bay, Point Lookout to Cedar Point; aerial and surface firing range and target area, U.S. Naval Air...) The regulations. (i) Through navigation of surface craft outside the target areas will be permitted at...

Low carbohydrate diets may increase risk of neural tube defects.

PubMed

Desrosiers, Tania A; Siega-Riz, Anna Maria; Mosley, Bridget S; Meyer, Robert E

2018-01-25

Folic acid fortification significantly reduced the prevalence of neural tube defects (NTDs) in the United States. The popularity of "low carb" diets raises concern that women who intentionally avoid carbohydrates, thereby consuming fewer fortified foods, may not have adequate dietary intake of folic acid. To assess the association between carbohydrate intake and NTDs, we analyzed data from the National Birth Defects Prevention Study from 1,740 mothers of infants, stillbirths, and terminations with anencephaly or spina bifida (cases), and 9,545 mothers of live born infants without a birth defect (controls) conceived between 1998 and 2011. Carbohydrate and folic acid intake before conception were estimated from food frequency questionnaire responses. Restricted carbohydrate intake was defined as ≤5th percentile among controls. Odds ratios were estimated with logistic regression and adjusted for maternal race/ethnicity, education, alcohol use, folic acid supplement use, study center, and caloric intake. Mean dietary intake of folic acid among women with restricted carbohydrate intake was less than half that of other women (p < .01), and women with restricted carbohydrate intake were slightly more likely to have an infant with an NTD (AOR = 1.30, 95% CI: 1.02, 1.67). This is the first study to examine the association between carbohydrate intake and NTDs among pregnancies conceived postfortification. We found that women with restricted carbohydrate intake were 30% more likely to have an infant with anencephaly or spina bifida. However, more research is needed to understand the pathways by which restricted carbohydrate intake might increase the risk of NTDs. © 2018 Wiley Periodicals, Inc.

Differential Effects of Two Fermentable Carbohydrates on Central Appetite Regulation and Body Composition

PubMed Central

Gibson, Glenn R.; Tuohy, Kieran M.; Sharma, Raj Kumar; Swann, Jonathan R.; Deaville, Eddie R.; Sleeth, Michele L.; Thomas, E. Louise; Holmes, Elaine; Bell, Jimmy D.; Frost, Gary

2012-01-01

activity in the hypothalamic appetite centers. Differential effects of fermentable carbohydrates open new possibilities for nutritionally targeting appetite regulation and body composition. PMID:22952656

[Specific problems posed by carbohydrate utilization in the rainbow trout].

PubMed

Bergot, F

1979-01-01

Carbohydrate incorporation in trout diets arises problems both at digestive and metabolic levels. Digestive utilization of carbohydrate closely depends on their molecular weight. In addition, in the case of complex carbohydrates (starches), different factors such as the level of incorporation, the amount consumed and the physical state of starch influence the digestibility. The measurement of digestibility in itself is confronted with methodological difficulties. The way the feces are collected can affect the digestion coefficient. Dietary carbohydrates actually serve as a source of energy. Nevertheless, above a certain level in the diet, intolerance phenomena may appear. The question that arises now is to establish the optimal part that carbohydrates can take in the metabolizable energy of a given diet.

Function-based classification of carbohydrate-active enzymes by recognition of short, conserved peptide motifs.

PubMed

Busk, Peter Kamp; Lange, Lene

2013-06-01

Functional prediction of carbohydrate-active enzymes is difficult due to low sequence identity. However, similar enzymes often share a few short motifs, e.g., around the active site, even when the overall sequences are very different. To exploit this notion for functional prediction of carbohydrate-active enzymes, we developed a simple algorithm, peptide pattern recognition (PPR), that can divide proteins into groups of sequences that share a set of short conserved sequences. When this method was used on 118 glycoside hydrolase 5 proteins with 9% average pairwise identity and representing four characterized enzymatic functions, 97% of the proteins were sorted into groups correlating with their enzymatic activity. Furthermore, we analyzed 8,138 glycoside hydrolase 13 proteins including 204 experimentally characterized enzymes with 28 different functions. There was a 91% correlation between group and enzyme activity. These results indicate that the function of carbohydrate-active enzymes can be predicted with high precision by finding short, conserved motifs in their sequences. The glycoside hydrolase 61 family is important for fungal biomass conversion, but only a few proteins of this family have been functionally characterized. Interestingly, PPR divided 743 glycoside hydrolase 61 proteins into 16 subfamilies useful for targeted investigation of the function of these proteins and pinpointed three conserved motifs with putative importance for enzyme activity. Furthermore, the conserved sequences were useful for cloning of new, subfamily-specific glycoside hydrolase 61 proteins from 14 fungi. In conclusion, identification of conserved sequence motifs is a new approach to sequence analysis that can predict carbohydrate-active enzyme functions with high precision.

Mangiferin Stimulates Carbohydrate Oxidation and Protects Against Metabolic Disorders Induced by High-Fat Diets

PubMed Central

Apontes, Pasha; Liu, Zhongbo; Su, Kai; Benard, Outhiriaradjou; Youn, Dou Y.; Li, Xisong; Li, Wei; Mirza, Raihan H.; Bastie, Claire C.; Jelicks, Linda A.; Pessin, Jeffrey E.; Muzumdar, Radhika H.; Sauve, Anthony A.

2014-01-01

Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyperglycemia, and insulin resistance. In addition, carbohydrate utilization as a fuel is substantially inhibited. Correction or reversal of these effects during high-fat diet (HFD) intake is of exceptional interest in light of widespread occurrence of diet-associated metabolic disorders in global human populations. Here we report that mangiferin (MGF), a natural compound (the predominant constituent of Mangifera indica extract from the plant that produces mango), protected against HFD-induced weight gain, increased aerobic mitochondrial capacity and thermogenesis, and improved glucose and insulin profiles. To obtain mechanistic insight into the basis for these effects, we determined that mice exposed to an HFD combined with MGF exhibited a substantial shift in respiratory quotient from fatty acid toward carbohydrate utilization. MGF treatment significantly increased glucose oxidation in muscle of HFD-fed mice without changing fatty acid oxidation. These results indicate that MGF redirects fuel utilization toward carbohydrates. In cultured C2C12 myotubes, MGF increased glucose and pyruvate oxidation and ATP production without affecting fatty acid oxidation, confirming in vivo and ex vivo effects. Furthermore, MGF inhibited anaerobic metabolism of pyruvate to lactate but enhanced pyruvate oxidation. A key target of MGF appears to be pyruvate dehydrogenase, determined to be activated by MGF in a variety of assays. These findings underscore the therapeutic potential of activation of carbohydrate utilization in correction of metabolic syndrome and highlight the potential of MGF to serve as a model compound that can elicit fuel-switching effects. PMID:24848064

Dietary carbohydrates and triacylglycerol metabolism.

PubMed

Roche, H M

1999-02-01

There is a growing body of scientific evidence which demonstrates that plasma triacylglycerol (TAG) concentration, especially in the postprandial state, is an important risk factor in relation to the development of CHD. Postprandial hypertriacylglycerolaemia is associated with a number of adverse metabolic risk factors, including the preponderance of small dense LDL, low HDL-cholesterol concentrations and elevated factor VII activity. Traditionally, a low-fat high-carbohydrate diet was used to prevent CHD because it effectively reduces plasma cholesterol concentrations, but this dietary regimen increases plasma TAG concentrations and reduces HDL-cholesterol concentrations. There is substantial epidemiological evidence which demonstrates that high plasma TAG and low plasma HDL concentrations are associated with an increased risk of CHD. Thus, there is reason for concern that the adverse effects of low-fat high-carbohydrate diets on TAG and HDL may counteract or negate the beneficial effect of reducing LDL-cholesterol concentrations. Although there have been no prospective studies to investigate whether reduced fat intake has an adverse effect on CHD, there is strong epidemiological evidence that reducing total fat intake is not protective against CHD. On the other hand, high-fat diets predispose to obesity, and central obesity adversely affects TAG metabolism. There is substantial evidence that in free-living situations low-fat high-carbohydrate diets lead to weight loss, which in turn will correct insulin resistance and plasma TAG metabolism. Clearly there is a need for prospective studies to resolve the issue as to whether low-fat high-carbohydrate diets play an adverse or beneficial role in relation to the development of CHD.

doGlycans-Tools for Preparing Carbohydrate Structures for Atomistic Simulations of Glycoproteins, Glycolipids, and Carbohydrate Polymers for GROMACS.

PubMed

Danne, Reinis; Poojari, Chetan; Martinez-Seara, Hector; Rissanen, Sami; Lolicato, Fabio; Róg, Tomasz; Vattulainen, Ilpo

2017-10-23

Carbohydrates constitute a structurally and functionally diverse group of biological molecules and macromolecules. In cells they are involved in, e.g., energy storage, signaling, and cell-cell recognition. All of these phenomena take place in atomistic scales, thus atomistic simulation would be the method of choice to explore how carbohydrates function. However, the progress in the field is limited by the lack of appropriate tools for preparing carbohydrate structures and related topology files for the simulation models. Here we present tools that fill this gap. Applications where the tools discussed in this paper are particularly useful include, among others, the preparation of structures for glycolipids, nanocellulose, and glycans linked to glycoproteins. The molecular structures and simulation files generated by the tools are compatible with GROMACS.

doGlycans–Tools for Preparing Carbohydrate Structures for Atomistic Simulations of Glycoproteins, Glycolipids, and Carbohydrate Polymers for GROMACS

PubMed Central

2017-01-01

Carbohydrates constitute a structurally and functionally diverse group of biological molecules and macromolecules. In cells they are involved in, e.g., energy storage, signaling, and cell–cell recognition. All of these phenomena take place in atomistic scales, thus atomistic simulation would be the method of choice to explore how carbohydrates function. However, the progress in the field is limited by the lack of appropriate tools for preparing carbohydrate structures and related topology files for the simulation models. Here we present tools that fill this gap. Applications where the tools discussed in this paper are particularly useful include, among others, the preparation of structures for glycolipids, nanocellulose, and glycans linked to glycoproteins. The molecular structures and simulation files generated by the tools are compatible with GROMACS. PMID:28906114

VARIATION IN THE GROUP-SPECIFIC CARBOHYDRATE OF GROUP A STREPTOCOCCI

PubMed Central

McCarty, Maclyn

1956-01-01

Soil organisms have been isolated which elaborate induced enzymes capable of attacking group A and variant (V) streptococcal carbohydrates. The V enzyme hydrolyzes V carbohydrate extensively to dialyzable split products with resultant total loss of precipitating activity with homologous antisera. The split products inhibit the reaction between intact V carbohydrate and its antiserum: evidence is presented which indicates that rhamnose oligosaccharides are responsible for the inhibitory effect. The serological specificity of the V carbohydrate thus appears to be primarily dependent on a rhamnose-rhamnose linkage. The effect of the A enzyme on A carbohydrate is characterized by the removal of 50 to 70 per cent of the total glucosamine in the form of free N-acetyl-glucosamine. As a result of this treatment, the residual carbohydrate loses its reactivity with specific group A antisera and at the same time develops markedly increased cross-reactivity with V antisera. This cross-reactivity is in turn eliminated by treatment with V enzyme. The evidence suggests that the specificity of group A carbohydrate is determined to a large extent by side chains of N-acetyl-glucosamine which also serve to mask underlying rhamnose-rhamnose linkages with V specificity. PMID:13367334

Multiple-Transportable Carbohydrate Effect on Long-Distance Triathlon Performance.

PubMed

Rowlands, David S; Houltham, Stuart D

2017-08-01

The ingestion of multiple (2:1 glucose-fructose) transportable carbohydrate in beverages at high rates (>78 g·h) during endurance exercise enhances exogenous carbohydrate oxidation, fluid absorption, gut comfort, and performance relative to glucose alone. However, during long-distance endurance competition, athletes prefer a solid-gel-drink format, and the effect size of multiple-transportable carbohydrate is unknown. This study aimed to determine the effect of multiple-transportable carbohydrate on triathlon competition performance when ingested within bars, gels, and drinks. A double-blind randomized controlled trial was conducted within two national-body sanctioned half-ironman triathlon races held 3 wk apart in 74 well-trained male triathletes (18-60 yr; >2 yr competition experience). Carbohydrate comprising glucose/maltodextrin-fructose (2:1 ratio) or standard isocaloric carbohydrate (glucose/maltodextrin only) was ingested before (94 g) and during the cycle (2.5 g·km) and run (7.8 g·km) sections, averaging 78.6 ± 6.6 g·h, partitioned to bars (25%), gels (35%), and drink (40%). Postrace, 0- to 10-unit Likert-type scales were completed to assess gut comfort and energy. The trial returned low dropout rate (9%), high compliance, and sensitivity (typical error 2.2%). The effect of multiple-transportable carbohydrate on performance time was -0.53% (95% confidence interval = -1.30% to 0.24%; small benefit threshold = -0.54%), with likelihood-based risk analysis supporting adoption (benefit-harm ratio = 48.9%:0.3%; odds ratio = 285:1). Covariate adjustments for preexercise body weight and heat stress had negligible impact performance. Multiple-transportable carbohydrate possibly lowered nausea during the swim and bike; otherwise, effects on gut comfort and perceived energy were negligible. Multiple-transportable (2:1 maltodextrin/glucose-fructose) compared with single-transportable carbohydrate ingested in differing format provided a small benefit to long

Low-Fat Versus Low-Carbohydrate Weight Reduction Diets

PubMed Central

Bradley, Una; Spence, Michelle; Courtney, C. Hamish; McKinley, Michelle C.; Ennis, Cieran N.; McCance, David R.; McEneny, Jane; Bell, Patrick M.; Young, Ian S.; Hunter, Steven J.

2009-01-01

OBJECTIVE Low-fat hypocaloric diets reduce insulin resistance and prevent type 2 diabetes in those at risk. Low-carbohydrate, high-fat diets are advocated as an alternative, but reciprocal increases in dietary fat may have detrimental effects on insulin resistance and offset the benefits of weight reduction. RESEARCH DESIGN AND METHODS We investigated a low-fat (20% fat, 60% carbohydrate) versus a low-carbohydrate (60% fat, 20% carbohydrate) weight reduction diet in 24 overweight/obese subjects ([mean ± SD] BMI 33.6 ± 3.7 kg/m2, aged 39 ± 10 years) in an 8-week randomized controlled trial. All food was weighed and distributed, and intake was calculated to produce a 500 kcal/day energy deficit. Insulin action was assessed by the euglycemic clamp and insulin secretion by meal tolerance test. Body composition, adipokine levels, and vascular compliance by pulse-wave analysis were also measured. RESULTS Significant weight loss occurred in both groups (P < 0.01), with no difference between groups (P = 0.40). Peripheral glucose uptake increased, but there was no difference between groups (P = 0.28), and suppression of endogenous glucose production was also similar between groups. Meal tolerance–related insulin secretion decreased with weight loss with no difference between groups (P = 0.71). The change in overall systemic arterial stiffness was, however, significantly different between diets (P = 0.04); this reflected a significant decrease in augmentation index following the low-fat diet, compared with a nonsignificant increase within the low-carbohydrate group. CONCLUSIONS This study demonstrates comparable effects on insulin resistance of low-fat and low-carbohydrate diets independent of macronutrient content. The difference in augmentation index may imply a negative effect of low-carbohydrate diets on vascular risk. PMID:19720791

Carbohydrate intake, glycemic index and prostate cancer risk

PubMed Central

Vidal, Adriana C.; Williams, Christina D.; Allott, Emma H.; Howard, Lauren E.; Grant, Delores J.; McPhail, Megan; Sourbeer, Katharine N.; Pao-Hwa, Lin; Boffetta, Paolo; Hoyo, Cathrine; Freedland, Stephen J.

2014-01-01

BACKGROUND Reported associations between dietary carbohydrate and prostate cancer (PC) risk are poorly characterized by race. METHODS We analyzed the association between carbohydrate intake, glycemic index (GI), and PC risk in a study of white (N=262) and black (N=168) veterans at the Durham VA Hospital. Cases were 156 men with biopsy-confirmed PC and controls (N=274) had a PSA test but were not recommended for biopsy. Diet was assessed before biopsy with a self-administered food frequency questionnaire. Logistic regression models were used to estimate PC risk. RESULTS In multivariable analyses, higher carbohydrate intake, measured as percent of energy from carbohydrates, was associated with reduced PC risk (3rd vs. 1st tertile, OR=0.41, 95%CI 0.21–0.81, p=0.010), though this only reached significance in white men (p-trend=0.029). GI was unrelated to PC risk among all men, but suggestively linked with reduced PC risk in white men (p-trend=0.066) and increased PC risk in black men (p-trend=0.172), however the associations were not significant. Fiber intake was not associated with PC risk (all p-trends >0.55). Higher carbohydrate intake was associated with reduced risk of high-grade (p-trend=0.016), but not low-grade PC (p-trend=0.593). CONCLUSIONS Higher carbohydrate intake may be associated with reduced risk of overall and high-grade PC. Future larger studies are needed to confirm these findings. PMID:25417840

Dietary strategies for the management of cardiovascular risk: role of dietary carbohydrates.

PubMed

Macdonald, Ian A

2014-05-01

Carbohydrate-rich foods are an essential component of the diet, providing the glucose that is continuously required by the nervous system and some other cells and tissues in the body for normal function. There is some concern that too much carbohydrate or certain types of carbohydrate such as fructose or the high glycaemic index carbohydrate foods that produce large, rapid increases in blood glucose may be detrimental to health. This review considers these issues and also summarises the public health advice currently available in Europe and the USA concerning dietary carbohydrates. The UK Scientific Advisory Committee on Nutrition is currently reviewing carbohydrates and health, and the subsequent report should help clarify some of the concerns regarding carbohydrates and health.

One-step synthesis of carbohydrate esters as antibacterial and antifungal agents.

PubMed

AlFindee, Madher N; Zhang, Qian; Subedi, Yagya Prasad; Shrestha, Jaya P; Kawasaki, Yukie; Grilley, Michelle; Takemoto, Jon Y; Chang, Cheng-Wei Tom

2018-02-01

Carbohydrate esters are biodegradable, and the degraded adducts are naturally occurring carbohydrates and fatty acids which are environmentally friendly and non-toxic to human. A simple one-step regioselective acylation of mono-carbohydrates has been developed that leads to the synthesis of a wide range of carbohydrate esters. Screening of these acylated carbohydrates revealed that several compounds were active against a panel of bacteria and fungi, including Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Candida albicans, Cryptococcus neoformans, Aspergillus flavus and Fusarium graminearum. Unlike prior studies on carbohydrate esters that focus only on antibacterial applications, our compounds are found to be active against both bacteria and fungi. Furthermore, the synthetic methodology is suitable to scale-up production for a variety of acylated carbohydrates. The identified lead compound, MAN014, can be used as an antimicrobial in applications such as food processing and preservation and for treatment of bacterial and fungal diseases in animals and plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modulation of the Gastrointestinal Microbiome with Nondigestible Fermentable Carbohydrates To Improve Human Health.

PubMed

Deehan, Edward C; Duar, Rebbeca M; Armet, Anissa M; Perez-Muñoz, Maria Elisa; Jin, Mingliang; Walter, Jens

2017-09-01

There is a clear association between the gastrointestinal (GI) microbiome and the development of chronic noncommunicable diseases, providing a rationale for the development of strategies that target the GI microbiota to improve human health. In this article, we discuss the potential of supplementing the human diet with nondigestible fermentable carbohydrates (NDFCs) to modulate the composition, structure, diversity, and metabolic potential of the GI microbiome in an attempt to prevent or treat human disease. The current concepts by which NDFCs can be administered to humans, including prebiotics, fermentable dietary fibers, and microbiota-accessible carbohydrates, as well as the mechanisms by which these carbohydrates exert their health benefits, are discussed. Epidemiological research presents compelling evidence for the health effects of NDFCs, with clinical studies providing further support for some of these benefits. However, rigorously designed human intervention studies with well-established clinical markers and microbial endpoints are still essential to establish (i) the clinical efficiency of specific NDFCs, (ii) the causal role of the GI microbiota in these effects, (iii) the underlying mechanisms involved, and (iv) the degree by which inter-individual differences between GI microbiomes influence these effects. Such studies would provide the mechanistic understanding needed for a systematic application of NDFCs to improve human health via GI microbiota modulation while also allowing the personalization of these dietary strategies.

Lignocentric analysis of a carbohydrate-producing lignocellulosic biorefinery process.

PubMed

Narron, Robert H; Han, Qiang; Park, Sunkyu; Chang, Hou-Min; Jameel, Hasan

2017-10-01

A biologically-based lignocellulosic biorefinery process for obtaining carbohydrates from raw biomass was investigated across six diverse biomasses (three hardwoods & three nonwoods) for the purpose of decoding lignin's influence on sugar production. Acknowledging that lignin could positively alter the economics of an entire process if valorized appropriately, we sought to correlate the chemical properties of lignin within the process to the traditional metrics associated with carbohydrate production-cellulolytic digestibility and total sugar recovery. Based on raw carbohydrate, enzymatic recovery ranged from 40 to 64% w/w and total recovery ranged from 70 to 87% w/w. Using nitrobenzene oxidation to quantify non-condensed lignin structures, it was found that raw hardwoods bearing increasing non-condensed S/V ratios (2.5-5.1) render increasing total carbohydrate recovery from hardwood biomasses. This finding indicates that the chemical structure of hardwood lignin influences the investigated biorefinery process' ability to generate carbohydrates from a given raw hardwood feedstock. Copyright © 2017 Elsevier Ltd. All rights reserved.

Laforin, a dual specificity phosphatase that dephosphorylates complex carbohydrates.

PubMed

Worby, Carolyn A; Gentry, Matthew S; Dixon, Jack E

2006-10-13

Laforin is the only phosphatase in the animal kingdom that contains a carbohydrate-binding module. Mutations in the gene encoding laforin result in Lafora disease, a fatal autosomal recessive neurodegenerative disorder, which is diagnosed by the presence of intracellular deposits of insoluble complex carbohydrates known as Lafora bodies. We demonstrate that laforin interacts with proteins known to be involved in glycogen metabolism and rule out several of these proteins as potential substrates. Surprisingly, we find that laforin displays robust phosphatase activity against a phosphorylated complex carbohydrate. Furthermore, this activity is unique to laforin, since several other phosphatases are unable to dephosphorylate polysaccharides. Finally, fusing the carbohydrate-binding module of laforin to the dual specific phosphatase VHR does not result in the ability of this phosphatase to dephosphorylate polysaccharides. Therefore, we hypothesize that laforin is unique in its ability to utilize a phosphorylated complex carbohydrate as a substrate and that this function may be necessary for the maintenance of normal cellular glycogen.

Bringing research into a first semester organic chemistry laboratory with the multistep synthesis of carbohydrate-based HIV inhibitor mimics.

PubMed

Pontrello, Jason K

2015-01-01

Benefits of incorporating research experiences into laboratory courses have been well documented, yet examples of research projects designed for the first semester introductory organic chemistry lab course are extremely rare. To address this deficiency, a Carbohydrate-Based human immunodeficiency virus (HIV) Inhibitor project consisting of a synthetic scheme of four reactions was developed for and implemented in the first semester organic lab. Students carried out the synthetic reactions during the last 6 of 10 total labs in the course, generating carbohydrate-based dimeric target molecules modeled after published dimers with application in HIV therapy. The project was designed to provide a research experience through use of literature procedures for reactions performed, exploration of variation in linker length in the target structure, and synthesis of compounds not previously reported in the scientific literature. Project assessment revealed strong student support, indicating enhanced engagement and interest in the course as a direct result of the use of scientific literature and the applications of the synthesized carbohydrate-based molecules. Regardless of discussed challenges in designing a research project for the first semester lab course, the finding from data analysis that a project implemented in the first semester lab had significantly greater student impact than a second semester project should provide motivation for development of additional research projects for a first semester organic course. © 2015 The International Union of Biochemistry and Molecular Biology.

Carbohydrate and fat: considerations for energy and more

USDA-ARS?s Scientific Manuscript database

Historically, carbohydrates and fats were valued on their caloric contributions to diets. Feeding recommendations for these feed fractions now address inclusion levels, as well as consideration of the positive and negative effects of specific types of these nutrients. Feed carbohydrate characterizat...

Isthmin targets cell-surface GRP78 and triggers apoptosis via induction of mitochondrial dysfunction.

PubMed

Chen, M; Zhang, Y; Yu, V C; Chong, Y-S; Yoshioka, T; Ge, R

2014-05-01

Isthmin (ISM) is a secreted 60-kDa protein that potently induces endothelial cell (EC) apoptosis. It suppresses tumor growth and angiogenesis in mice when stably overexpressed in cancer cells. Although αvβ5 integrin serves as a low-affinity receptor for ISM, the mechanism by which ISM mediates antiangiogenesis and apoptosis in ECs remain to be fully resolved. In this work, we report the identification of cell-surface glucose-regulated protein 78 kDa (GRP78) as a high-affinity receptor for ISM (Kd=8.6 nM). We demonstrated that ISM-GRP78 interaction triggers apoptosis not only in activated ECs but also in cancer cells expressing high level of cell-surface GRP78. Normal cells and benign tumor cells tend to express low level of cell-surface GRP78 and are resistant to ISM-induced apoptosis. Upon binding to GRP78, ISM is internalized into ECs through clathrin-dependent endocytosis that is essential for its proapoptotic activity. Once inside the cell, ISM co-targets with GRP78 to mitochondria where it interacts with ADP/ATP carriers on the inner membrane and blocks ATP transport from mitochondria to cytosol, thereby causing apoptosis. Hence, ISM is a novel proapoptotic ligand that targets cell-surface GRP78 to trigger apoptosis by inducing mitochondrial dysfunction. The restricted and high-level expression of cell-surface GRP78 on cancer cells and cancer ECs make them uniquely susceptible to ISM-targeted apoptosis. Indeed, systemic delivery of recombinant ISM potently suppressed subcutaneous 4T1 breast carcinoma and B16 melanoma growth in mice by eliciting apoptosis selectively in the cancer cells and cancer ECs. Together, this work reveals a novel ISM-GRP78 apoptosis pathway and demonstrates the potential of ISM as a cancer-specific and dual-targeting anticancer agent.

Isthmin targets cell-surface GRP78 and triggers apoptosis via induction of mitochondrial dysfunction

PubMed Central

Chen, M; Zhang, Y; Yu, V C; Chong, Y-S; Yoshioka, T; Ge, R

2014-01-01

Isthmin (ISM) is a secreted 60-kDa protein that potently induces endothelial cell (EC) apoptosis. It suppresses tumor growth and angiogenesis in mice when stably overexpressed in cancer cells. Although αvβ5 integrin serves as a low-affinity receptor for ISM, the mechanism by which ISM mediates antiangiogenesis and apoptosis in ECs remain to be fully resolved. In this work, we report the identification of cell-surface glucose-regulated protein 78 kDa (GRP78) as a high-affinity receptor for ISM (Kd=8.6 nM). We demonstrated that ISM-GRP78 interaction triggers apoptosis not only in activated ECs but also in cancer cells expressing high level of cell-surface GRP78. Normal cells and benign tumor cells tend to express low level of cell-surface GRP78 and are resistant to ISM-induced apoptosis. Upon binding to GRP78, ISM is internalized into ECs through clathrin-dependent endocytosis that is essential for its proapoptotic activity. Once inside the cell, ISM co-targets with GRP78 to mitochondria where it interacts with ADP/ATP carriers on the inner membrane and blocks ATP transport from mitochondria to cytosol, thereby causing apoptosis. Hence, ISM is a novel proapoptotic ligand that targets cell-surface GRP78 to trigger apoptosis by inducing mitochondrial dysfunction. The restricted and high-level expression of cell-surface GRP78 on cancer cells and cancer ECs make them uniquely susceptible to ISM-targeted apoptosis. Indeed, systemic delivery of recombinant ISM potently suppressed subcutaneous 4T1 breast carcinoma and B16 melanoma growth in mice by eliciting apoptosis selectively in the cancer cells and cancer ECs. Together, this work reveals a novel ISM-GRP78 apoptosis pathway and demonstrates the potential of ISM as a cancer-specific and dual-targeting anticancer agent. PMID:24464222

Accounting for genotype–by-environment interactions and non-additive genetic variation in genomic selection for water-soluble carbohydrate concentration in wheat

USDA-ARS?s Scientific Manuscript database

Abiotic stress tolerance traits are often complex and recalcitrant targets for conventional breeding improvement in many crop species. This study evaluated the potential of genomic selection to predict water-soluble carbohydrate concentration (WSCC), an important drought tolerance trait, in wheat un...

Dietary carbohydrates, components of energy balance, and associated health outcomes.

PubMed

Smith, Harry A; Gonzalez, Javier T; Thompson, Dylan; Betts, James A

2017-10-01

The role of dietary carbohydrates in the development of obesity and associated metabolic dysfunction has recently been questioned. Within the last decade, the Scientific Advisory Committee on Nutrition carried out a comprehensive evaluation of the role of dietary carbohydrates in human health. The current review aims to complement and extend this report by providing specific consideration of the effects of the component parts of energy balance, their interactions, and their culmination on energy storage and health. PubMed was searched for all published trials that had a minimum follow-up period of 3 months and were designed to manipulate dietary carbohydrate intake, irrespective of resultant differences in absolute carbohydrate dose (grams per day). Dietary carbohydrate manipulation has little effect on the individual components of energy balance that have been assessed. However, the role of dietary carbohydrates in influencing physical activity has yet to be assessed using gold-standard measurement tools. Moreover, adherence to a diet of modified carbohydrate content has not been found to result in a consistent pattern of changes in weight or indirect measures of metabolic health. However, certain markers of cardiovascular disease risk (ie, blood triglycerides and high-density lipoprotein cholesterol) may respond positively to a reduction in dietary carbohydrates. © The Author(s) 2017. Published by Oxford University Press on behalf of the International Life Sciences Institute. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Does Carbohydrate Intake During Endurance Running Improve Performance? A Critical Review.

PubMed

Wilson, Patrick B

2016-12-01

Wilson, PB. Does carbohydrate intake during endurance running improve performance? A critical review. J Strength Cond Res 30(12): 3539-3559, 2016-Previous review articles assessing the effects of carbohydrate ingestion during prolonged exercise have not focused on running. Given the popularity of distance running and the widespread use of carbohydrate supplements, this article reviewed the evidence for carbohydrate ingestion during endurance running. The criteria for inclusion were (a) experimental studies reported in English language including a performance task, (b) moderate-to-high intensity exercise >60 minutes (intermittent excluded), and (c) carbohydrate ingestion (mouth rinsing excluded). Thirty studies were identified with 76 women and 505 men. Thirteen of the 17 studies comparing a carbohydrate beverage(s) with water or a placebo found a between-condition performance benefit with carbohydrate, although heterogeneity in protocols precludes clear generalizations about the expected effect sizes. Additional evidence suggests that (a) performance benefits are most likely to occur during events >2 hours, although several studies showed benefits for tasks lasting 90-120 minutes; (b) consuming carbohydrate beverages above ad libitum levels increases gastrointestinal discomfort without improving performance; (c) carbohydrate gels do not influence performance for events lasting 16-21 km; and (d) multiple saccharides may benefit events >2 hours if intake is ≥1.3 g·min Given that most participants were fasted young men, inferences regarding women, adolescents, older runners, and those competing in fed conditions are hampered. Future studies should address these limitations to further elucidate the role of carbohydrate ingestion during endurance running.

Carbohydrate Counting and Diabetes

MedlinePlus

... of cooked nonstarchy vegetables or a cup of raw vegetables has only about 5 grams of carbohydrate. ... help you find added sugars, such as sugar, raw sugar, brown sugar, and invert sugar—a mixture ...

Strategies in biomimetic surface engineering of nanoparticles for biomedical applications

NASA Astrophysics Data System (ADS)

Gong, Yong-Kuan; Winnik, Françoise M.

2012-01-01

Engineered nanoparticles (NPs) play an increasingly important role in biomedical sciences and in nanomedicine. Yet, in spite of significant advances, it remains difficult to construct drug-loaded NPs with precisely defined therapeutic effects, in terms of release time and spatial targeting. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Upon injection in the blood stream or following oral administation, NPs have to bypass numerous barriers prior to reaching their intended target. A particularly successful design strategy consists in masking the NP to the biological environment by covering it with an outer surface mimicking the composition and functionality of the cell's external membrane. This review describes this biomimetic approach. First, we outline key features of the composition and function of the cell membrane. Then, we present recent developments in the fabrication of molecules that mimic biomolecules present on the cell membrane, such as proteins, peptides, and carbohydrates. We present effective strategies to link such bioactive molecules to the NPs surface and we highlight the power of this approach by presenting some exciting examples of biomimetically engineered NPs useful for multimodal diagnostics and for target-specific drug/gene delivery applications. Finally, critical directions for future research and applications of biomimetic NPs are suggested to the readers.

Effects of high-fat and high-carbohydrate diets on fat and carbohydrate oxidation and plasma metabolites in healthy cats.

PubMed

Gooding, M A; Flickinger, E A; Atkinson, J L; Duncan, I J H; Shoveller, A K

2014-06-01

High-fat (HF) or high-carbohydrate (HC) diets (30% fat, 18.9% carbohydrate; HF and 10% fat, 46.3% carbohydrate; HC) and lengths of adaptation were investigated in cats (Felis catus; 10 ± 2 months, 3.6 ± 0.3 kg). Cats randomly received each treatment for 14 days in a crossover design with a 14-day washout period between each diet. Three 22-h indirect calorimetry studies were conducted after acute (day 0), semichronic (day 4) and chronic (day 13) dietary exposure. Blood samples were collected after a 24-h fast on days 1, 5 and 14. When cats consumed the HC and HF diet, oxidation of the restricted nutrient exceeded intake while oxidation of the nutrient in excess matched intake. Mean max energy expenditure (EE) of cats consuming the HF and HC diet were 107 and 102 kcal/kg(0.67)/day and occurred at a mean of 4 and 12 h post-feeding respectively. Maximal fat (0.90 g/h) and carbohydrate (carbohydrate; 1.42 g/h) oxidation were attained at 26 min and 10.4 h post-feeding respectively. The changes observed in macronutrient oxidation and EE suggest that cats adapt whole-body nutrient metabolism in response to changes in dietary macronutrient content, but may require longer than 14 day to adapt to a macronutrient that is present at a lower concentration in the diet. Journal of Animal Physiology and Animal Nutrition © 2013 Blackwell Verlag GmbH.

[Systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography].

PubMed

Fu, Qing; Wang, Jun; Liang, Tu; Xu, Xiaoyong; Jin, Yu

2013-11-01

A systematic evaluation of retention behavior of carbohydrates in hydrophilic interaction liquid chromatography (HILIC) was performed. The influences of mobile phase, stationary phase and buffer salt on the retention of carbohydrates were investigated. According to the results, the retention time of carbohydrates decreased as the proportion of acetonitrile in mobile phase decreased. Increased time of carbohydrates was observed as the concentration of buffer salt in mobile phase increased. The retention behavior of carbohydrates was also affected by organic solvent and HILIC stationary phase. Furthermore, an appropriate retention equation was used in HILIC mode. The retention equation lnk = a + blnC(B) + cC(B) could quantitatively describe the retention factors of carbohydrates of plant origin with good accuracy: the relative error of the predicted time to actual time was less than 0.3%. The evaluation results could provide guidance for carbohydrates to optimize the experimental conditions in HILIC method development especially for carbohydrate separation

Carbohydrate intake, glycemic index and prostate cancer risk.

PubMed

Vidal, Adriana C; Williams, Christina D; Allott, Emma H; Howard, Lauren E; Grant, Delores J; McPhail, Megan; Sourbeer, Katharine N; Hwa, Lin Pao; Boffetta, Paolo; Hoyo, Cathrine; Freedland, Stephen J

2015-03-01

Reported associations between dietary carbohydrate and prostate cancer (PC) risk are poorly characterized by race. We analyzed the association between carbohydrate intake, glycemic index (GI), and PC risk in a study of white (N = 262) and black (N = 168) veterans at the Durham VA Hospital. Cases were 156 men with biopsy-confirmed PC and controls (N = 274) had a PSA test but were not recommended for biopsy. Diet was assessed before biopsy with a self-administered food frequency questionnaire. Logistic regression models were used to estimate PC risk. In multivariable analyzes, higher carbohydrate intake, measured as percent of energy from carbohydrates, was associated with reduced PC risk (3rd vs. 1st tertile, OR = 0.41, 95% CI 0.21-0.81, P = 0.010), though this only reached significance in white men (p-trend = 0.029). GI was unrelated to PC risk among all men, but suggestively linked with reduced PC risk in white men (p-trend = 0.066) and increased PC risk in black men (p-trend = 0.172), however, the associations were not significant. Fiber intake was not associated with PC risk (all p-trends > 0.55). Higher carbohydrate intake was associated with reduced risk of high-grade (p-trend = 0.016), but not low-grade PC (p-trend = 0.593). Higher carbohydrate intake may be associated with reduced risk of overall and high-grade PC. Future larger studies are needed to confirm these findings. © 2014 Wiley Periodicals, Inc.

Thin-film preparation by back-surface irradiation pulsed laser deposition using metal powder targets

NASA Astrophysics Data System (ADS)

Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Yamauchi, Makiko; Suda, Yoshiaki

2017-01-01

Several kinds of functional thin films were deposited using a new thin-film preparation method named the back-surface irradiation pulsed laser deposition (BIPLD) method. In this BIPLD method, powder targets were used as the film source placed on a transparent target holder, and then a visible-wavelength pulsed laser was irradiated from the holder side to the substrate. Using this new method, titanium oxide and boron nitride thin films were deposited on the silicon substrate. Surface scanning electron microscopy (SEM) images suggest that all of the thin films were deposited on the substrate with some large droplets irrespective of the kind of target used. The deposition rate of the films prepared by using this method was calculated from film thickness and deposition time to be much lower than that of the films prepared by conventional PLD. X-ray diffraction (XRD) measurement results suggest that rutile and anatase TiO2 crystal peaks were formed for the films prepared using the TiO2 rutile powder target. Crystal peaks of hexagonal boron nitride were observed for the films prepared using the boron nitride powder target. The crystallinity of the prepared films was changed by annealing after deposition.

Chemical Changes in Carbohydrates Produced by Thermal Processing.

ERIC Educational Resources Information Center

Hoseney, R. Carl

1984-01-01

Discusses chemical changes that occur in the carbohydrates found in food products when these products are subjected to thermal processing. Topics considered include browning reactions, starch found in food systems, hydrolysis of carbohydrates, extrusion cooking, processing of cookies and candies, and alterations in gums. (JN)

Simulation of carbohydrates, from molecular docking to dynamics in water.

PubMed

Sapay, Nicolas; Nurisso, Alessandra; Imberty, Anne

2013-01-01

Modeling of carbohydrates is particularly challenging because of the variety of structures resulting for the high number of monosaccharides and possible linkages and also because of their intrinsic flexibility. The development of carbohydrate parameters for molecular modeling is still an active field. Nowadays, main carbohydrates force fields are GLYCAM06, CHARMM36, and GROMOS 45A4. GLYCAM06 includes the largest choice of compounds and is compatible with the AMBER force fields and associated. Furthermore, AMBER includes tools for the implementation of new parameters. When looking at protein-carbohydrate interaction, the choice of the starting structure is of importance. Such complex can be sometimes obtained from the Protein Data Bank-although the stereochemistry of sugars may require some corrections. When no experimental data is available, molecular docking simulation is generally used to the obtain protein-carbohydrate complex coordinates. As molecular docking parameters are not specifically dedicated to carbohydrates, inaccuracies should be expected, especially for the docking of polysaccharides. This issue can be addressed at least partially by combining molecular docking with molecular dynamics simulation in water.

Structural Features Facilitating Tumor Cell Targeting and Internalization by Bleomycin and Its Disaccharide

PubMed Central

2016-01-01

We have shown previously that the bleomycin (BLM) carbohydrate moiety can recapitulate the tumor cell targeting effects of the entire BLM molecule, that BLM itself is modular in nature consisting of a DNA-cleaving aglycone which is delivered selectively to the interior of tumor cells by its carbohydrate moiety, and that there are disaccharides structurally related to the BLM disaccharide which are more efficient than the natural disaccharide at tumor cell targeting/uptake. Because BLM sugars can deliver molecular cargoes selectively to tumor cells, and thus potentially form the basis for a novel antitumor strategy, it seemed important to consider additional structural features capable of affecting the efficiency of tumor cell recognition and delivery. These included the effects of sugar polyvalency and net charge (at physiological pH) on tumor cell recognition, internalization, and trafficking. Since these parameters have been shown to affect cell surface recognition, internalization, and distribution in other contexts, this study has sought to define the effects of these structural features on tumor cell recognition by bleomycin and its disaccharide. We demonstrate that both can have a significant effect on tumor cell binding/internalization, and present data which suggests that the metal ions normally bound by bleomycin following clinical administration may significantly contribute to the efficiency of tumor cell uptake, in addition to their characterized function in DNA cleavage. A BLM disaccharide-Cy5** conjugate incorporating the positively charged dipeptide d-Lys-d-Lys was found to associate with both the mitochondria and the nuclear envelope of DU145 cells, suggesting possible cellular targets for BLM disaccharide–cytotoxin conjugates. PMID:25905565

Comparing the responses of rumen ciliate protozoa and bacteria to excess carbohydrate.

PubMed

Teixeira, César R V; Lana, Rogério de Paula; Tao, Junyi; Hackmann, Timothy J

2017-06-01

When given excess carbohydrate, certain microbial species respond by storing energy (synthesizing reserve carbohydrate), but other species respond by dissipating the energy as heat (spilling energy). To determine the importance of these responses in the rumen microbial community, this study quantified the responses of mixed ciliate protozoa vs bacteria to glucose. We hypothesized that ciliates would direct more glucose to synthesis of reserve carbohydrate (and less to energy spilling) than would bacteria. Ciliates and bacteria were isolated from rumen fluid using filtration and centrifugation, resuspended in nitrogen-free buffer to limit growth, and dosed with 5 mM glucose. Compared with bacteria, ciliates consumed glucose >3-fold faster and synthesized reserve carbohydrate 4-fold faster. They incorporated 53% of glucose carbon into reserve carbohydrate-nearly double the value (27%) for bacteria. Energy spilling was not detected for ciliates, as all heat production (104%) was accounted by synthesis of reserve carbohydrate and endogenous metabolism. For bacteria, reserve carbohydrate and endogenous metabolism accounted for only 68% of heat production, and spilling was detected within 11 min of dosing glucose. These results suggest that ciliates alter the course of ruminal carbohydrate metabolism by outcompeting bacteria for excess carbohydrate, maximizing reserve carbohydrate synthesis, and minimizing energy spilling. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Separate influence of dietary carbohydrate and fibre on the metabolic control in diabetes.

PubMed

Riccardi, G; Rivellese, A; Pacioni, D; Genovese, S; Mastranzo, P; Mancini, M

1984-02-01

To clarify the separate influences of digestible carbohydrate and of dietary fibre on blood glucose control and serum lipoproteins, 14 diabetic patients (six Type 1 and eight Type 2) were submitted to three weight-maintaining diets for 10 days each: (1) low carbohydrate/low fibre diet with 42% carbohydrate and 20 g fibre; (2) high carbohydrate/low fibre diet (carbohydrate 53%, fibre 16 g); (3) high carbohydrate/ high fibre diet (carbohydrate 53%, fibre 54 g). In comparison with the low carbohydrate/low fibre diet, the 2-h post-prandial blood glucose and the daily blood glucose profile decreased significantly on the high carbohydrate/high fibre diet, without significant changes during the high carbohydrate/low fibre diet. The diet-induced modifications of blood glucose control were similar in both types of diabetic patients (two-way analysis of variance: F = 5.86, p less than 0.02 for dietary treatment and F = 2.09, NS for type of diabetes). Total and low-density lipoprotein cholesterol were also decreased after the high carbohydrate/high fibre diet in comparison with the low carbohydrate/low fibre diet (p less than 0.001 for both), while they were not significantly modified after the high carbohydrate/low fibre diet. Again the modifications of low density lipoprotein cholesterol induced by diet were similar in both types of diabetic patients (F = 10.02, p less than 0.005 for dietary treatment and F = 0.14 for type of diabetes, NS). High-density lipoprotein cholesterol was lower after the two test diets than after the low carbohydrate/low fibre diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Determining a carbohydrate profile for Hansenula polymorpha

NASA Technical Reports Server (NTRS)

Petersen, G. R.

1985-01-01

The determination of the levels of carbohydrates in the yeast Hansenula polymorpha required the development of new analytical procedures. Existing fractionation and analytical methods were adapted to deal with the problems involved with the lysis of whole cells. Using these new procedures, the complete carbohydrate profiles of H. polymorpha and selected mutant strains were determined and shown to correlate favourably with previously published results.

Carbohydrate-based electrochemical biosensor for detection of a cancer biomarker in human plasma.

PubMed

Devillers, Marion; Ahmad, Lama; Korri-Youssoufi, Hafsa; Salmon, Laurent

2017-10-15

Autocrine motility factor (AMF) is a tumor-secreted cytokine that stimulates tumor cell motility in vitro and metastasis in vivo. AMF could be detected in serum or urine of cancer patients with worse prognosis. Reported as a cancer biomarker, AMF secretion into body fluids might be closely related to metastases formation. In this study, a sensitive and specific carbohydrate-based electrochemical biosensor was designed for the detection and quantification of a protein model of AMF, namely phosphoglucose isomerase from rabbit muscle (RmPGI). Indeed, RmPGI displays high homology with AMF and has been shown to have AMF activity. The biosensor was constructed by covalent binding of the enzyme substrate d-fructose 6-phosphate (F6P). Immobilization was achieved on a gold surface electrode following a bottom-up approach through an aminated surface obtained by electrochemical patterning of ethylene diamine and terminal amine polyethylene glycol chain to prevent non-specific interactions. Carbohydrate-protein interactions were quantified in a range of 10 fM to 100nM. Complex formation was analyzed through monitoring of the redox couple Fe 2+ /Fe 3+ by electrochemical impedance spectroscopy and square wave voltammetry. The F6P-biosensor demonstrates a detection limit of 6.6 fM and high selectivity when compared to other non-specific glycolytic proteins such as d-glucose-6-phosphate dehydrogenase. Detection of protein in spiked plasma was demonstrated and accuracy of 95% is obtained compared to result obtained in PBS (phosphate buffered saline). F6P-biosensor is a very promising proof of concept required for the design of a carbohydrate-based electrochemical biosensor using the enzyme substrate as bioreceptor. Such biosensor could be generalized to detect other protein biomarkers of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

Photo-controlled aptamers delivery by dual surface gold-magnetic nanoparticles for targeted cancer therapy.

PubMed

Zhao, Jian; Tu, Keyao; Liu, Yanlei; Qin, Yulei; Wang, Xiwei; Qi, Lifeng; Shi, Donglu

2017-11-01

Dual surfaced dumbbell-like gold magnetic nanoparticles (Au-Fe 3 O 4 ) were synthesized for targeted aptamers delivery. Their unique biological properties were characterized as a smart photo-controlled drug carrier. DNA aptamers targeting vascular endothelial growth factor (VEGF) were assembled onto the surface of Au-Fe 3 O 4 by electrostatic absorption. The binding capacity of the nanoparticles with VEGF aptamers was confirmed by gel electrophoresis. The targeted recognization of ovarian cancer cells by the aptamers-functionalized Au-Fe 3 O 4 nanoparticles (Apt-Au-Fe 3 O 4 NPs) was observed by confocal microscopy. Apt-Au-Fe 3 O 4 was found to bind with SKOV-3 ovarian cancer cells specifically, leading to marked intracellular release of aptamers upon plasmon-resonant light (605nm) radiation, and to enhance the in vitro inhibition against tumor cell proliferation. The results show high potential of Apt-Au-Fe 3 O 4 as a targeted cancer hyperthermia carrier by remote control with high spatial/temporal resolution. Copyright © 2017. Published by Elsevier B.V.

Selection of dietary protein and carbohydrate by rats: Changes with maturation

NASA Technical Reports Server (NTRS)

Yokogoshi, Hidehiko; Theall, Cynthia L.; Wurtman, Richard J.

1985-01-01

Weaning (21-day-old; 40-50 g) male rats given simultaneous access to foods, containing 18 percent casein and 15 or 70 percent carbohydrate (dextrin), tended to consume only 29-35 percent as much protein as carbohydrate (i.e., protein/carbohydrate ratios were 0.29-0.35). With maturation, when animals weighed 100 g or more, about half continued this pattern of nutrient choice, but the others abruptly began to consume considerably larger proportions of protein, exhibiting protein/carbohydrate ratios as high as 0.80-1.00. Each adult animal's protein/carbohydrate ratio tended to vary only slightly (s.e. = 3 percent of means). Adult protein/carbohydrate ratios were not correlated with fasting brain 5-HT or 5-HIAA levels. These marked differences among rats in eating behavior would not be observed when--as is usually the case--animals are given access to only one diet.

Investigation of Carbohydrate Recognition via Computer Simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Quentin R.; Lindsay, Richard J.; Petridis, Loukas

Carbohydrate recognition by proteins, such as lectins and other (bio)molecules, can be essential for many biological functions. Interest has arisen due to potential protein and drug design and future bioengineering applications. A quantitative measurement of carbohydrate-protein interaction is thus important for the full characterization of sugar recognition. Here, we focus on the aspect of utilizing computer simulations and biophysical models to evaluate the strength and specificity of carbohydrate recognition in this review. With increasing computational resources, better algorithms and refined modeling parameters, using state-of-the-art supercomputers to calculate the strength of the interaction between molecules has become increasingly mainstream. We reviewmore » the current state of this technique and its successful applications for studying protein-sugar interactions in recent years.« less

Investigation of Carbohydrate Recognition via Computer Simulation

DOE PAGES

Johnson, Quentin R.; Lindsay, Richard J.; Petridis, Loukas; ...

2015-04-28

Carbohydrate recognition by proteins, such as lectins and other (bio)molecules, can be essential for many biological functions. Interest has arisen due to potential protein and drug design and future bioengineering applications. A quantitative measurement of carbohydrate-protein interaction is thus important for the full characterization of sugar recognition. Here, we focus on the aspect of utilizing computer simulations and biophysical models to evaluate the strength and specificity of carbohydrate recognition in this review. With increasing computational resources, better algorithms and refined modeling parameters, using state-of-the-art supercomputers to calculate the strength of the interaction between molecules has become increasingly mainstream. We reviewmore » the current state of this technique and its successful applications for studying protein-sugar interactions in recent years.« less

Effects of caffeine and carbohydrate mouth rinses on repeated sprint performance.

PubMed

Beaven, C Martyn; Maulder, Peter; Pooley, Adrian; Kilduff, Liam; Cook, Christian

2013-06-01

Our purpose was to examine the effectiveness of carbohydrate and caffeine mouth rinses in enhancing repeated sprint ability. Previously, studies have shown that a carbohydrate mouth rinse (without ingestion) has beneficial effects on endurance performance that are related to changes in brain activity. Caffeine ingestion has also demonstrated positive effects on sprint performance. However, the effects of carbohydrate or caffeine mouth rinses on intermittent sprints have not been examined previously. Twelve males performed 5 × 6-s sprints interspersed with 24 s of active recovery on a cycle ergometer. Twenty-five milliliters of either a noncaloric placebo, a 6% glucose, or a 1.2% caffeine solution was rinsed in the mouth for 5 s prior to each sprint in a double-blinded and balanced cross-over design. Postexercise maximal heart rate and perceived exertion were recorded, along with power measures. A second experiment compared a combined caffeine-carbohydrate rinse with carbohydrate only. Compared with the placebo mouth rinse, carbohydrate substantially increased peak power in sprint 1 (22.1 ± 19.5 W; Cohen's effect size (ES), 0.81), and both caffeine (26.9 ± 26.9 W; ES, 0.71) and carbohydrate (39.1 ± 25.8 W; ES, 1.08) improved mean power in sprint 1. Experiment 2 demonstrated that a combination of caffeine and carbohydrate improved sprint 1 power production compared with carbohydrate alone (36.0 ± 37.3 W; ES, 0.81). We conclude that carbohydrate and (or) caffeine mouth rinses may rapidly enhance power production, which could have benefits for specific short sprint exercise performance. The ability of a mouth-rinse intervention to rapidly improve maximal exercise performance in the absence of fatigue suggests a central mechanism.

Remodelling of the hepatic epigenetic landscape of glucose-intolerant rainbow trout (Oncorhynchus mykiss) by nutritional status and dietary carbohydrates.

PubMed

Marandel, Lucie; Lepais, Olivier; Arbenoits, Eva; Véron, Vincent; Dias, Karine; Zion, Marie; Panserat, Stéphane

2016-08-26

The rainbow trout, a carnivorous fish, displays a 'glucose-intolerant' phenotype revealed by persistent hyperglycaemia when fed a high carbohydrate diet (HighCHO). Epigenetics refers to heritable changes in gene activity and is closely related to environmental changes and thus to metabolism adjustments governed by nutrition. In this study we first assessed in the trout liver whether and how nutritional status affects global epigenome modifications by targeting DNA methylation and histone marks previously reported to be affected in metabolic diseases. We then examined whether dietary carbohydrates could affect the epigenetic landscape of duplicated gluconeogenic genes previously reported to display changes in mRNA levels in trout fed a high carbohydrate diet. We specifically highlighted global hypomethylation of DNA and hypoacetylation of H3K9 in trout fed a HighCHO diet, a well-described phenotype in diabetes. g6pcb2 ohnologs were also hypomethylated at specific CpG sites in these animals according to their up-regulation. Our findings demonstrated that the hepatic epigenetic landscape can be affected by both nutritional status and dietary carbohydrates in trout. The mechanism underlying the setting up of these epigenetic modifications has now to be explored in order to improve understanding of its impact on the glucose intolerant phenotype in carnivorous teleosts.

Remodelling of the hepatic epigenetic landscape of glucose-intolerant rainbow trout (Oncorhynchus mykiss) by nutritional status and dietary carbohydrates

PubMed Central

Marandel, Lucie; Lepais, Olivier; Arbenoits, Eva; Véron, Vincent; Dias, Karine; Zion, Marie; Panserat, Stéphane

2016-01-01

The rainbow trout, a carnivorous fish, displays a ‘glucose-intolerant’ phenotype revealed by persistent hyperglycaemia when fed a high carbohydrate diet (HighCHO). Epigenetics refers to heritable changes in gene activity and is closely related to environmental changes and thus to metabolism adjustments governed by nutrition. In this study we first assessed in the trout liver whether and how nutritional status affects global epigenome modifications by targeting DNA methylation and histone marks previously reported to be affected in metabolic diseases. We then examined whether dietary carbohydrates could affect the epigenetic landscape of duplicated gluconeogenic genes previously reported to display changes in mRNA levels in trout fed a high carbohydrate diet. We specifically highlighted global hypomethylation of DNA and hypoacetylation of H3K9 in trout fed a HighCHO diet, a well-described phenotype in diabetes. g6pcb2 ohnologs were also hypomethylated at specific CpG sites in these animals according to their up-regulation. Our findings demonstrated that the hepatic epigenetic landscape can be affected by both nutritional status and dietary carbohydrates in trout. The mechanism underlying the setting up of these epigenetic modifications has now to be explored in order to improve understanding of its impact on the glucose intolerant phenotype in carnivorous teleosts. PMID:27561320

Comparison of Continuous-Wave CO2 Lidar Calibration by use of Earth-Surface Targets in Laboratory and Airborne Measurements

NASA Technical Reports Server (NTRS)

Jarzembski, Maurice A.; Srivastava, Vandana

1998-01-01

Backscatter of several Earth surfaces was characterized in the laboratory as a function of incidence angle with a focused continuous-wave 9.1 micro meter CO2 Doppler lidar for use as possible calibration targets. Some targets showed negligible angular dependence, while others showed a slight increase with decreasing angle. The Earth-surface signal measured over the complex Californian terrain during a 1995 NASA airborne mission compared well with laboratory data. Distributions of the Earth's surface signal shows that the lidar efficiency can be estimated with a fair degree of accuracy, preferably with uniform Earth-surface targets during flight for airborne or space-based lidar.

Surface-Modified Nanocarriers for Nose-to-Brain Delivery: From Bioadhesion to Targeting

PubMed Central

Clementino, Adryana; Buttini, Francesca; Colombo, Gaia; Pescina, Silvia; Stanisçuaski Guterres, Silvia; Nicoli, Sara

2018-01-01

In the field of nasal drug delivery, nose-to-brain delivery is among the most fascinating applications, directly targeting the central nervous system, bypassing the blood brain barrier. Its benefits include dose lowering and direct brain distribution of potent drugs, ultimately reducing systemic side effects. Recently, nasal administration of insulin showed promising results in clinical trials for the treatment of Alzheimer’s disease. Nanomedicines could further contribute to making nose-to-brain delivery a reality. While not disregarding the need for devices enabling a formulation deposition in the nose’s upper part, surface modification of nanomedicines appears the key strategy to optimize drug delivery from the nasal cavity to the brain. In this review, nanomedicine delivery based on particle engineering exploiting surface electrostatic charges, mucoadhesive polymers, or chemical moieties targeting the nasal epithelium will be discussed and critically evaluated in relation to nose-to-brain delivery. PMID:29543755

Relationship of carbohydrate molecular spectroscopic features in combined feeds to carbohydrate utilization and availability in ruminants

NASA Astrophysics Data System (ADS)

Zhang, Xuewei; Yu, Peiqiang

To date, there is no study on the relationship between carbohydrate (CHO) molecular structures and nutrient availability of combined feeds in ruminants. The objective of this study was to use molecular spectroscopy to reveal the relationship between CHO molecular spectral profiles (in terms of functional groups (biomolecular, biopolymer) spectral peak area and height intensity) and CHO chemical profiles, CHO subfractions, energy values, and CHO rumen degradation kinetics of combined feeds of hulless barley with pure wheat dried distillers grains with solubles (DDGS) at five different combination ratios (hulless barley to pure wheat DDGS: 100:0, 75:25, 50:50, 25:75, 0:100). The molecular spectroscopic parameters assessed included: lignin biopolymer molecular spectra profile (peak area and height, region and baseline: ca. 1539-1504 cm-1); structural carbohydrate (STCHO, peaks area region and baseline: ca. 1485-1186 cm-1) mainly associated with hemi- and cellulosic compounds; cellulosic materials peak area (centered at ca. 1240 cm-1 with region and baseline: ca. 1272-1186 cm-1); total carbohydrate (CHO, peaks area region and baseline: ca. 1186-946 cm-1). The results showed that the functional groups (biomolecular, biopolymer) in the combined feeds are sensitive to the changes of carbohydrate chemical and nutrient profiles. The changes of the CHO molecular spectroscopic features in the combined feeds were highly correlated with CHO chemical profiles, CHO subfractions, in situ CHO rumen degradation kinetics and fermentable organic matter supply. Further study is needed to investigate possibility of using CHO molecular spectral features as a predictor to estimate nutrient availability in combined feeds for animals and quantify their relationship.

Photoswitchable carbohydrate-based fluorosurfactants as tuneable ice recrystallization inhibitors.

PubMed

Adam, Madeleine K; Hu, Yingxue; Poisson, Jessica S; Pottage, Matthew J; Ben, Robert N; Wilkinson, Brendan L

2017-02-01

Cryopreservation is an important technique employed for the storage and preservation of biological tissues and cells. The limited effectiveness and significant toxicity of conventionally-used cryoprotectants, such as DMSO, have prompted efforts toward the rational design of less toxic alternatives, including carbohydrate-based surfactants. In this paper, we report the modular synthesis and ice recrystallization inhibition (IRI) activity of a library of variably substituted, carbohydrate-based fluorosurfactants. Carbohydrate-based fluorosurfactants possessed a variable mono- or disaccharide head group appended to a hydrophobic fluoroalkyl-substituted azobenzene tail group. Light-addressable fluorosurfactants displayed weak-to-moderate IRI activity that could be tuned through selection of carbohydrate head group, position of the trifluoroalkyl group on the azobenzene ring, and isomeric state of the azobenzene tail fragment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduced Carbohydrate Availability Enhances the Susceptibility of Arabidopsis toward Colletotrichum higginsianum1[W][OA

PubMed Central

Engelsdorf, Timo; Horst, Robin J.; Pröls, Reinhard; Pröschel, Marlene; Dietz, Franziska; Hückelhoven, Ralph; Voll, Lars M.

2013-01-01

Colletotrichum higginsianum is a hemibiotrophic ascomycete fungus that is adapted to Arabidopsis (Arabidopsis thaliana). After breaching the host surface, the fungus establishes an initial biotrophic phase in the penetrated epidermis cell, before necrotrophic growth is initiated upon further host colonization. We observed that partitioning of major leaf carbohydrates was shifted in favor of sucrose and at the expense of starch during necrotrophic fungal growth. Arabidopsis mutants with impaired starch turnover were more susceptible toward C. higginsianum infection, exhibiting a strong negative correlation between diurnal carbohydrate accumulation and fungal proliferation for the tested genotypes. By altering the length of the light phase and employing additional genotypes impaired in nocturnal carbon mobilization, we revealed that reduced availability of carbon enhances susceptibility in the investigated pathosystem. Systematic starvation experiments resulted in two important findings. First, we showed that carbohydrate supply by the host is dispensable during biotrophic growth of C. higginsianum, while carbon deficiency was most harmful to the host during the necrotrophic colonization phase. Compared with the wild type, the increases in the total salicylic acid pool and camalexin accumulation were reduced in starch-free mutants at late interaction stages, while an increased ratio of free to total salicylic acid did not convey elevated pathogenesis-related gene expression in starch-free mutants. These observations suggest that reduced carbon availability dampens induced defense responses. In contrast, starch-free mutants were more resistant toward the fungal biotroph Erysiphe cruciferarum, indicating that reduced carbohydrate availability influences susceptibility differently in the interaction with the investigated hemibiotrophic and biotrophic fungal pathogens. PMID:23487433

Carbohydrate catabolic diversity of bifidobacteria and lactobacilli of human origin.

PubMed

McLaughlin, Heather P; Motherway, Mary O'Connell; Lakshminarayanan, Bhuvaneswari; Stanton, Catherine; Paul Ross, R; Brulc, Jennifer; Menon, Ravi; O'Toole, Paul W; van Sinderen, Douwe

2015-06-16

Because increased proportions of particular commensal bacteria such as bifidobacteria and lactobacilli have been linked to human health through a variety of mechanisms, there is corresponding interest in identifying carbohydrates that promote growth and metabolic activity of these bacteria. We evaluated the ability of 20 carbohydrates, including several commercially available carbohydrates that are sold as prebiotic ingredients, to support growth of 32 human-derived isolates belonging to the genera Bifidobacterium and Lactobacillus, including those isolated from healthy elderly subjects. In general, bifidobacterial strains were shown to display more diverse carbohydrate utilization profiles compared to the tested Lactobacillus species, with several bifidobacterial strains capable of metabolizing xylo-oligosaccharide (XOS), arabinoxylan, maltodextrin, galactan and carbohydrates containing fructo-oligosaccharide (FOS) components. In contrast, maltodextrin, galactan, arabinogalactan and galactomannan did not support robust growth (≥0.8 OD600 nm) of any of the Lactobacillus strains assessed. Carbohydrate fermentation was variable among strains tested of the same species for both genera. This study advances our knowledge of polysaccharide utilization by human gut commensals, and provides information for the rational design of selective prebiotic food ingredients. Copyright © 2015 Elsevier B.V. All rights reserved.

Biologically-Inspired Peptide Reagents for Enhancing IMS-MS Analysis of Carbohydrates

NASA Astrophysics Data System (ADS)

Bohrer, Brian C.; Clemmer, David E.

2011-09-01

The binding properties of a peptidoglycan recognition protein are translated via combinatorial chemistry into short peptides. Non-adjacent histidine, tyrosine, and arginine residues in the protein's binding cleft that associate specifically with the glycan moiety of a peptidoglycan substrate are incorporated into linear sequences creating a library of 27 candidate tripeptide reagents (three possible residues permutated across three positions). Upon electrospraying the peptide library and carbohydrate mixtures, some noncovalent complexes are observed. The binding efficiencies of the peptides vary according to their amino acid composition as well as the disaccharide linkage and carbohydrate ring-type. In addition to providing a charge-carrier for the carbohydrate, peptide reagents can also be used to differentiate carbohydrate isomers by ion mobility spectrometry. The utility of these peptide reagents as a means of enhancing ion mobility analysis of carbohydrates is illustrated by examining four glucose-containing disaccharide isomers, including a pair that is not resolved by ion mobility alone. The specificity and stoichiometry of the peptide-carbohydrate complexes are also investigated. Trihistidine demonstrates both suitable binding efficiency and successful resolution of disaccharides isomers, suggesting it may be a useful reagent in IMS analyses of carbohydrates.

Sports Nutrition for the Primary Care Physician: The Importance of Carbohydrate.

ERIC Educational Resources Information Center

Wheeler, Keith B.

1989-01-01

Discusses the relationship between nutrition and fatigue and how carbohydrates and timing of carbohydrate consumption can affect fatigued athletes. Nutrition plays a significant role in successful training and competition. Key concerns are the specific needs of athletes for carbohydrates before, during, and after exercise. (Author/SM)

Thermodynamic evidence for Ca2+-mediated self-aggregation of Lewis X gold glyconanoparticles. A model for cell adhesion via carbohydrate-carbohydrate interaction.

PubMed

de la Fuente, Jesús M; Eaton, Peter; Barrientos, Africa G; Menéndez, Margarita; Penadés, Soledad

2005-05-04

Thermodynamic evidence for the selective Ca(2+)-mediated self-aggregation via carbohydrate-carbohydrate interactions of gold glyconanoparticles functionalized with the disaccharides lactose (lacto-Au) and maltose (malto-Au), or the biologically relevant trisaccharide Lewis X (Le(X)-Au), was obtained by isothermal titration calorimetry. The aggregation process was also directly visualized by atomic force microscopy. It was shown in the case of the trisaccharide Lewis X that the Ca(2+)-mediated aggregation is a slow process that takes place with a decrease in enthalpy of 160 +/- 30 kcal mol(-)(1), while the heat evolved in the case of lactose and maltose glyconanoparticles was very low and thermal equilibrium was quickly achieved. Measurements in the presence of Mg(2+) and Na(+) cations confirm the selectivity for Ca(2+) of Le(X)-Au glyconanoparticles. The relevance of this result to cell-cell adhesion process mediated by carbohydrate-carbohydrate interactions is discussed.

Computational Investigation of Glycosylation Effects on a Family 1 Carbohydrate-binding Module*

PubMed Central

Taylor, Courtney B.; Talib, M. Faiz; McCabe, Clare; Bu, Lintao; Adney, William S.; Himmel, Michael E.; Crowley, Michael F.; Beckham, Gregg T.

2012-01-01

Carbohydrate-binding modules (CBMs) are ubiquitous components of glycoside hydrolases, which degrade polysaccharides in nature. CBMs target specific polysaccharides, and CBM binding affinity to cellulose is known to be proportional to cellulase activity, such that increasing binding affinity is an important component of performance improvement. To ascertain the impact of protein and glycan engineering on CBM binding, we use molecular simulation to quantify cellulose binding of a natively glycosylated Family 1 CBM. To validate our approach, we first examine aromatic-carbohydrate interactions on binding, and our predictions are consistent with previous experiments, showing that a tyrosine to tryptophan mutation yields a 2-fold improvement in binding affinity. We then demonstrate that enhanced binding of 3–6-fold over a nonglycosylated CBM is achieved by the addition of a single, native mannose or a mannose dimer, respectively, which has not been considered previously. Furthermore, we show that the addition of a single, artificial glycan on the anterior of the CBM, with the native, posterior glycans also present, can have a dramatic impact on binding affinity in our model, increasing it up to 140-fold relative to the nonglycosylated CBM. These results suggest new directions in protein engineering, in that modifying glycosylation patterns via heterologous expression, manipulation of culture conditions, or introduction of artificial glycosylation sites, can alter CBM binding affinity to carbohydrates and may thus be a general strategy to enhance cellulase performance. Our results also suggest that CBM binding studies should consider the effects of glycosylation on binding and function. PMID:22147693

Serotonin, carbohydrates, and atypical depression.

PubMed

Møller, S E

1992-01-01

At least three categories of atypical depression have been described. The hysteroid dysphoria is characterized by repeated episodes of depressed mood in response to feeling rejected, and a craving for sweets and chocolate. Two other issues are characterized by a cyclical occurrence of changes of mood and appetite, i.e., the late luteal phase dysphoric disorder (DSM-III-R, appendix), or "the premenstrual syndrome" (PMS), and the major depression with seasonal pattern (DSM-III-R), or seasonal affective disorder (SAD). The reactive mood changes are frequently accompanied by features as hypersomnia, lethargy and increased appetite, particularly with a preference for carbohydrates. Central serotonin pathways participate in the regulation of mood and behavioural impulsivity, and modulate eating patterns qualitatively and quantitatively. Depressives with PMS og SAD benefit, in general, from treatments with serotonin potentiating drugs, suggesting that brain serotonin plays a role in the pathophysiology. Ingestion of carbohydrates increases the plasma ratio of tryptophan to other large neutral amino acids in man and animal, and the serotonin synthesis in the rat brain. Based on these findings it has been suggested that the excessive carbohydrate intake by patients with PMS and SAD reflects a self-medication that temporarily relieves the vegetative symptoms via an increased central serotonergic activity.

Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates.

PubMed

Sacks, Frank M; Bray, George A; Carey, Vincent J; Smith, Steven R; Ryan, Donna H; Anton, Stephen D; McManus, Katherine; Champagne, Catherine M; Bishop, Louise M; Laranjo, Nancy; Leboff, Meryl S; Rood, Jennifer C; de Jonge, Lilian; Greenway, Frank L; Loria, Catherine M; Obarzanek, Eva; Williamson, Donald A

2009-02-26

The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize

Comparison of Weight-Loss Diets with Different Compositions of Fat, Protein, and Carbohydrates

PubMed Central

Sacks, Frank M.; Bray, George A.; Carey, Vincent J.; Smith, Steven R.; Ryan, Donna H.; Anton, Stephen D.; McManus, Katherine; Champagne, Catherine M.; Bishop, Louise M.; Laranjo, Nancy; Leboff, Meryl S.; Rood, Jennifer C.; de Jonge, Lilian; Greenway, Frank L.; Loria, Catherine M.; Obarzanek, Eva; Williamson, Donald A.

2009-01-01

BACKGROUND The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. METHODS We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. RESULTS At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. CONCLUSIONS Reduced-calorie diets result in clinically meaningful weight loss regardless of

Optimal partitioning theory revisited: nonstructural carbohydrates dominate root mass responses to nitrogen.

PubMed

Kobe, Richard K; Iyer, Meera; Walters, Michael B

2010-01-01

Under optimal partitioning theory (OPT), plants preferentially allocate biomass to acquire the resource that most limits growth. Within this framework, higher root mass under low nutrients is often assumed to reflect an allocation response to build more absorptive surface. However, higher root mass also could result from increased storage of total nonstructural carbohydrates (TNC) without an increase in non-storage mass or root surface area. To test the relative contributions of TNC and non-storage mass as components of root mass responses to resources, we grew seedlings of seven northern hardwood tree species (black, red, and white oak, sugar and red maple, American beech, and black cherry) in a factorial light x nitrogen (N) greenhouse experiment. Because root mass is a coarse metric of absorptive surface, we also examined treatment effects on fine-root surface area (FRSA). Consistent with OPT, total root mass as a proportion of whole-plant mass generally was greater in low vs. high N. However, changes in root mass were influenced by TNC mass in all seven species and were especially strong in the three oak species. In contrast, non-storage mass contributed to increased total root mass under low N in three of the seven species. Root morphology also responded, with higher fine-root surface area (normalized to root mass) under low vs. high N in four species. Although biomass partitioning responses to resources were consistent with OPT, our results challenge the implicit assumption that increases in root mass under low nutrient levels primarily reflect allocation shifts to build more root surface area. Rather, root responses to low N included increases in: TNC, non-storage mass and fine-root surface area, with increases in TNC being the largest and most consistent of these responses. The greatest TNC accumulation occurred when C was abundant relative to N. Total nonstructural carbohydrates storage could provide seedlings a carbon buffer when respiratory or growth

Intact carbohydrate structures as part of the melanoidin skeleton.

PubMed

Cämmerer, Bettina; Jalyschko, Walentina; Kroh, Lothar W

2002-03-27

Model melanoidins from monomeric, oligomeric, and polymeric carbohydrates, and amino acids formed under aqueous as well as water-free reaction conditions, were submitted to acidic catalyzed hydrolysis. Their degradation products were detected qualitatively and quantitatively by HPTLC and HPLC-DAD. A considerable amount of monomer carbohydrates from hydrolysis of model melanoidins formed under water-free reaction conditions was detected. It can be seen clearly that the amount of carbohydrates released increased with increasing degree of polymerization of the carbohydrates used as starting material. In comparison, the hydrolysis of melanoidins formed in aqueous condition resulted in only a small glucose release. It seems that in the Maillard reaction under water-free conditions, a significant amount of di- and oligomer carbohydrates were incorporated into the melanoidin skeleton as complete oligomer with intact glycosidic bond, forming side chains at the melanoidin skeleton. Additional side chains could be formed by transglycosylation reactions. With increasing water content, hydrothermolytic as well as retro-aldol reactions of the starting carbonyl components became significant, and therefore the possibility of forming side chains decreased. The results are consistent with the postulated melanoidin structure being built up mainly from sugar degradation products, probably branched via amino compounds.

Carbohydrate Content in the GDM Diet: Two Views: View 1: Nutrition Therapy in Gestational Diabetes: The Case for Complex Carbohydrates.

PubMed

Hernandez, Teri L

2016-05-01

IN BRIEF Restriction of dietary carbohydrate has been the cornerstone for treatment of gestational diabetes mellitus (GDM). However, there is evidence that a balanced liberalization of complex carbohydrate as part of an overall eating plan in GDM meets treatment goals and may mitigate maternal adipose tissue insulin resistance, both of which may promote optimal metabolic outcomes for mother and offspring.

Characterization of carbohydrate-protein matrices for nutrient delivery.

PubMed

Zhou, Yankun; Roos, Yrjö H

2011-05-01

Amorphous carbohydrates may show glass transition and crystallization as a result of thermal or water plasticization. Proteins often affect the state transitions of carbohydrates in carbohydrate-protein systems. Water sorption behavior and effects of water on glass transition and crystallization in freeze-dried lactose, trehalose, lactose-casein (3: 1), lactose-soy protein isolate (3:1), trehalose-casein (3:1), and trehalose-soy protein isolate (3:1) systems were studied. Water sorption was determined gravimetrically as a function of time, and Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models were fitted to the experimental data. Glass transition temperature (T(g)) and instant crystallization temperature (T(ic)) in anhydrous and water plasticized systems were measured using differential scanning calorimetry (DSC). The Gordon-Taylor equation was used to model water content dependence of the T(g) values. The critical water content and water activity (a(w)) at 24 °C were calculated and crystallization of lactose and trehalose in the systems was followed at and above 0.54 a(w). Carbohydrate-protein systems showed higher amounts of sorbed water and less rapid sugar crystallization than pure sugars. A greater sugar crystallization delay was found in carbohydrate-casein systems than in carbohydrate-soy protein isolate systems. The T(g) and T(ic) values decreased with increasing water content and a(w). However, higher T(ic) values for lactose-protein systems were found than for lactose at the same a(w). Trehalose showed lower T(ic) value than lactose at 0.44 a(w) but no instant crystallization was measured below 0.44 a(w). State diagrams for each system are useful in selecting processing parameters and storage conditions in nutrient delivery applications. © 2011 Institute of Food Technologists®

Carbohydrate-Loading: A Safe and Effective Method of Improving Endurance Performance.

ERIC Educational Resources Information Center

Beeker, Richard T.; Israel, Richard G.

Carbohydrate-loading prior to distance events is a common practice among endurance athletes. The purposes of this paper are to review previous research and to clarify misconceptions which may exist concerning carbohydrate-loading. The most effective method of carbohydrate-loading involves a training run of sufficient intensity and duration to…

A randomized trial of a low-carbohydrate diet for obesity.

PubMed

Foster, Gary D; Wyatt, Holly R; Hill, James O; McGuckin, Brian G; Brill, Carrie; Mohammed, B Selma; Szapary, Philippe O; Rader, Daniel J; Edman, Joel S; Klein, Samuel

2003-05-22

Despite the popularity of the low-carbohydrate, high-protein, high-fat (Atkins) diet, no randomized, controlled trials have evaluated its efficacy. We conducted a one-year, multicenter, controlled trial involving 63 obese men and women who were randomly assigned to either a low-carbohydrate, high-protein, high-fat diet or a low-calorie, high-carbohydrate, low-fat (conventional) diet. Professional contact was minimal to replicate the approach used by most dieters. Subjects on the low-carbohydrate diet had lost more weight than subjects on the conventional diet at 3 months (mean [+/-SD], -6.8+/-5.0 vs. -2.7+/-3.7 percent of body weight; P=0.001) and 6 months (-7.0+/-6.5 vs. -3.2+/-5.6 percent of body weight, P=0.02), but the difference at 12 months was not significant (-4.4+/-6.7 vs. -2.5+/-6.3 percent of body weight, P=0.26). After three months, no significant differences were found between the groups in total or low-density lipoprotein cholesterol concentrations. The increase in high-density lipoprotein cholesterol concentrations and the decrease in triglyceride concentrations were greater among subjects on the low-carbohydrate diet than among those on the conventional diet throughout most of the study. Both diets significantly decreased diastolic blood pressure and the insulin response to an oral glucose load. The low-carbohydrate diet produced a greater weight loss (absolute difference, approximately 4 percent) than did the conventional diet for the first six months, but the differences were not significant at one year. The low-carbohydrate diet was associated with a greater improvement in some risk factors for coronary heart disease. Adherence was poor and attrition was high in both groups. Longer and larger studies are required to determine the long-term safety and efficacy of low-carbohydrate, high-protein, high-fat diets. Copyright 2003 Massachusetts Medical Society

The role of complex carbohydrate catabolism in the pathogenesis of invasive streptococci

PubMed Central

Shelburne, Samuel A.; Davenport, Michael T.; Keith, David B.; Musser, James M.

2009-01-01

Historically, the study of bacterial catabolism of complex carbohydrates has contributed to understanding basic bacterial physiology. Recently, however, genome-wide screens of streptococcal pathogenesis have identified genes encoding proteins involved in complex carbohydrate catabolism as participating in pathogen infectivity. Subsequent studies have focused on specific mechanisms by which carbohydrate utilization proteins might contribute to the ability of streptococci to colonize and infect the host. Moreover, transcriptome and biochemical analyses have uncovered novel regulatory pathways by which streptococci link environmental carbohydrate availability to virulence factor production. Herein we review new insights into the role of complex carbohydrates in streptococcal host-pathogen interaction. PMID:18508271

Impact of carbohydrates on weight regain.

PubMed

Bosy-Westphal, Anja; Müller, Manfred J

2015-07-01

Research on obesity treatment has shifted its focus from weight loss to weight-loss maintenance strategies. The conventional approach of a low-fat diet is challenged by insights from glycemic effects of carbohydrates on body weight regulation. Metabolic and endocrine adaptations to weight loss that contribute to weight regain involve reduced energy expenditure, increased insulin sensitivity, and enhanced orexigenic signals. This review summarizes the impact of carbohydrates on energetic efficiency, partitioning of weight regain as fat and lean mass, and appetite control. Both the amount and frequency of postprandial glycemia add to body weight regulation after weight loss and strengthen the concept of glycemic index and glycemic load. In addition, dietary fiber and slowly or poorly absorbable functional sugars modify gastrointestinal peptides involved in appetite and metabolic regulation and exert prebiotic effects. Current evidence suggests that a low-glycemic load diet with a preference for low-glycemic index foods and integration of slowly digestible, poorly absorbable carbohydrates may improve weight-loss maintenance. Future studies should investigate the health benefits of low glycemic functional sweeteners (e.g., isomaltulose and tagatose).

Carbohydrates as Fat Replacers.

PubMed

Peng, Xingyun; Yao, Yuan

2017-02-28

The overconsumption of dietary fat contributes to various chronic diseases, which encourages attempts to develop and consume low-fat foods. Simple fat reduction causes quality losses that impede the acceptance of foods. Fat replacers are utilized to minimize the quality deterioration after fat reduction or removal to achieve low-calorie, low-fat claims. In this review, the forms of fats and their functions in contributing to food textural and sensory qualities are discussed in various food systems. The connections between fat reduction and quality loss are described in order to clarify the rationales of fat replacement. Carbohydrate fat replacers usually have low calorie density and provide gelling, thickening, stabilizing, and other texture-modifying properties. In this review, carbohydrates, including starches, maltodextrins, polydextrose, gums, and fibers, are discussed with regard to their interactions with other components in foods as well as their performances as fat replacers in various systems.

[In vitro hepatic targeting tendency of galactosyl-anti CD3 McAb-TILS].

PubMed

Jiang, P; He, S; Zhang, C

1999-03-01

This study was undertaken to enhance the hepatic targeting tendency of tumor infiltrating lymphocytes (TILs) and hence to lower the recurrence rate of primary liver cancer after hepatectomy. Galactosyl-anti CD3McAb-TILs were prepared and then were incubated together with hepatocytes. Their interaction through asialoglycoprotein receptor-mediated mechanism was observed under the inverted phase contrast microscope. The carbohydrate density of galactosyl-anti CD3McAb and the combining rate of galactosyl-anti CD3McAb with TILs were measured. The results revealed that galactosyl-anti CD3 McAb-TIL obviously were adhered to hepatocytes. The carbohydrate density of galactosyl-anti CD3McAb was 62.18, and the combining rate of galactosyl-anti CD3McAb with TILs was 97.9%. The results suggested that in vitro hepatic targeting tendency of galactosyl-anti CD3McAb-TILs was satisfactory, and that the carbohydrate density of 62.18 and the combining rate of 97.9% ensured the effective use of TILs.

The effects of marine carbohydrates and glycosylated compounds on human health.

PubMed

Kang, Hee-Kyoung; Seo, Chang Ho; Park, Yoonkyung

2015-03-16

Marine organisms have been recognized as a valuable source of bioactive compounds with industrial and nutraceutical potential. Recently, marine-derived carbohydrates, including polysaccharides and low molecular weight glycosylated oligosaccharides, have attracted much attention because of their numerous health benefits. Moreover, several studies have reported that marine carbohydrates exhibit various biological activities, including antioxidant, anti-infection, anticoagulant, anti-inflammatory, and anti-diabetic effects. The present review discusses the potential industrial applications of bioactive marine carbohydrates for health maintenance and disease prevention. Furthermore, the use of marine carbohydrates in food, cosmetics, agriculture, and environmental protection is discussed.

Effects of Low-Carbohydrate and Low-Fat Diets

PubMed Central

Bazzano, Lydia A.; Hu, Tian; Reynolds, Kristi; Yao, Lu; Bunol, Calynn; Liu, Yanxi; Chen, Chung-Shiuan; Klag, Michael J.; Whelton, Paul K.; He, Jiang

2015-01-01

Background Low-carbohydrate diets are popular for weight loss, but their cardiovascular effects have not been well-studied, particularly in diverse populations. Objective To examine the effects of a low-carbohydrate diet compared with a low-fat diet on body weight and cardiovascular risk factors. Design A randomized, parallel-group trial. (ClinicalTrials.gov: NCT00609271) Setting A large academic medical center. Participants 148 men and women without clinical cardiovascular disease and diabetes. Intervention A low-carbohydrate (<40 g/d) or low-fat diet (<30% fat; <7% saturated fat). Both groups received dietary counseling at regular intervals throughout the trial. Measurements Data on weight, cardiovascular risk factors, and dietary composition were collected at 0, 3, 6, and 12 months. Results Sixty participants (82%) in the low-fat group and 59 (79%) in the low-carbohydrate group completed the intervention. At 12 months, participants on the low-carbohydrate diet had greater decreases in weight (mean difference in change, −3.5 kg [95% CI, −5.6 to −1.4 kg]; P < 0.001), fat mass (mean difference in change, −1.5% [CI, −2.6% to −0.4%]; P = 0.011), ratio of total to high-density lipoprotein (HDL) cholesterol (mean difference in change, −0.44 [CI, −0.71 to −0.16]; P = 0.002), and triglyceride level (mean difference in change, −0.16 mmol/L [−14.1 mg/dL] [CI, −0.31 to −0.01 mmol/L {−27.4 to −0.8 mg/dL}]; P = 0.038) and greater increases in HDL cholesterol level (mean difference in change, 0.18 mmol/L [7.0 mg/dL] [CI, 0.08 to 0.28 mmol/L {3.0 to 11.0 mg/dL}]; P< 0.001) than those on the low-fat diet. Limitation Lack of clinical cardiovascular disease end points. Conclusion The low-carbohydrate diet was more effective for weight loss and cardiovascular risk factor reduction than the low-fat diet. Restricting carbohydrate may be an option for persons seeking to lose weight and reduce cardiovascular risk factors. Primary Funding Source National

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility.

PubMed

Paik, Samuel Y; Epperson, Patrick M; Kasper, Kenneth M

2017-06-01

This article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measures in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm 2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm 2 , for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was not present

Bacteriophage-encoded virion-associated enzymes to overcome the carbohydrate barriers during the infection process.

PubMed

Latka, Agnieszka; Maciejewska, Barbara; Majkowska-Skrobek, Grazyna; Briers, Yves; Drulis-Kawa, Zuzanna

2017-04-01

Bacteriophages are bacterial viruses that infect the host after successful receptor recognition and adsorption to the cell surface. The irreversible adherence followed by genome material ejection into host cell cytoplasm must be preceded by the passage of diverse carbohydrate barriers such as capsule polysaccharides (CPSs), O-polysaccharide chains of lipopolysaccharide (LPS) molecules, extracellular polysaccharides (EPSs) forming biofilm matrix, and peptidoglycan (PG) layers. For that purpose, bacteriophages are equipped with various virion-associated carbohydrate active enzymes, termed polysaccharide depolymerases and lysins, that recognize, bind, and degrade the polysaccharide compounds. We discuss the existing diversity in structural locations, variable architectures, enzymatic specificities, and evolutionary aspects of polysaccharide depolymerases and virion-associated lysins (VALs) and illustrate how these aspects can correlate with the host spectrum. In addition, we present methods that can be used for activity determination and the application potential of these enzymes as antibacterials, antivirulence agents, and diagnostic tools.

Enzyme-based processing of soybean carbohydrate: Recent developments and future prospects.

PubMed

Al Loman, Abdullah; Ju, Lu-Kwang

2017-11-01

Soybean is well known for its high-value oil and protein. Carbohydrate is, however, an underutilized major component, representing almost 26-30% (w/w) of the dried bean. The complex soybean carbohydrate is not easily hydrolyzable and can cause indigestibility when included in food and feed. Enzymes can be used to hydrolyze the carbohydrate for improving soybean processing and value of soybean products. Here the enzyme-based processing developed for the following purposes is reviewed: hydrolysis of different carbohydrate-rich by/products from soybean processing, improvement of soybean oil extraction, and increase of nutritional value of soybean-based food and animal feed. Once hydrolyzed into fermentable sugars, soybean carbohydrate can find more value-added applications and further improve the overall economics of soybean processing. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of Carbohydrate Source on Genetic Competence in Streptococcus mutans.

PubMed

Moye, Zachary D; Son, Minjun; Rosa-Alberty, Ariana E; Zeng, Lin; Ahn, Sang-Joon; Hagen, Stephen J; Burne, Robert A

2016-08-01

The capacity to internalize and catabolize carbohydrates is essential for dental caries pathogens to persist and cause disease. The expression of many virulence-related attributes by Streptococcus mutans, an organism strongly associated with human dental caries, is influenced by the peptide signaling pathways that control genetic competence. Here, we demonstrate a relationship between the efficiency of competence signaling and carbohydrate source. A significant increase in the activity of the promoters for comX, comS, and comYA after exposure to competence-stimulating peptide (CSP) was observed in cells growing on fructose, maltose, sucrose, or trehalose as the primary carbohydrate source, compared to cells growing on glucose. However, only cells grown in the presence of trehalose or sucrose displayed a significant increase in transformation frequency. Notably, even low concentrations of these carbohydrates in the presence of excess glucose could enhance the expression of comX, encoding a sigma factor needed for competence, and the effects on competence were dependent on the cognate sugar:phosphotransferase permease for each carbohydrate. Using green fluorescent protein (GFP) reporter fusions, we observed that growth in fructose or trehalose resulted in a greater proportion of the population activating expression of comX and comS, encoding the precursor of comX-inducing peptide (XIP), after addition of CSP, than growth in glucose. Thus, the source of carbohydrate significantly impacts the stochastic behaviors that regulate subpopulation responses to CSP, which can induce competence in S. mutans The signaling pathways that regulate development of genetic competence in Streptococcus mutans are intimately intertwined with the pathogenic potential of the organism, impacting biofilm formation, stress tolerance, and expression of known virulence determinants. Induction of the gene for the master regulator of competence, ComX, by competence-stimulating peptide (CSP

Effects of Carbohydrate Source on Genetic Competence in Streptococcus mutans

PubMed Central

Moye, Zachary D.; Son, Minjun; Rosa-Alberty, Ariana E.; Zeng, Lin; Ahn, Sang-Joon

2016-01-01

ABSTRACT The capacity to internalize and catabolize carbohydrates is essential for dental caries pathogens to persist and cause disease. The expression of many virulence-related attributes by Streptococcus mutans, an organism strongly associated with human dental caries, is influenced by the peptide signaling pathways that control genetic competence. Here, we demonstrate a relationship between the efficiency of competence signaling and carbohydrate source. A significant increase in the activity of the promoters for comX, comS, and comYA after exposure to competence-stimulating peptide (CSP) was observed in cells growing on fructose, maltose, sucrose, or trehalose as the primary carbohydrate source, compared to cells growing on glucose. However, only cells grown in the presence of trehalose or sucrose displayed a significant increase in transformation frequency. Notably, even low concentrations of these carbohydrates in the presence of excess glucose could enhance the expression of comX, encoding a sigma factor needed for competence, and the effects on competence were dependent on the cognate sugar:phosphotransferase permease for each carbohydrate. Using green fluorescent protein (GFP) reporter fusions, we observed that growth in fructose or trehalose resulted in a greater proportion of the population activating expression of comX and comS, encoding the precursor of comX-inducing peptide (XIP), after addition of CSP, than growth in glucose. Thus, the source of carbohydrate significantly impacts the stochastic behaviors that regulate subpopulation responses to CSP, which can induce competence in S. mutans. IMPORTANCE The signaling pathways that regulate development of genetic competence in Streptococcus mutans are intimately intertwined with the pathogenic potential of the organism, impacting biofilm formation, stress tolerance, and expression of known virulence determinants. Induction of the gene for the master regulator of competence, ComX, by competence

Bacterial Adhesion of Streptococcus suis to Host Cells and Its Inhibition by Carbohydrate Ligands

PubMed Central

Kouki, Annika; Pieters, Roland J.; Nilsson, Ulf J.; Loimaranta, Vuokko; Finne, Jukka; Haataja, Sauli

2013-01-01

Streptococcus suis is a Gram-positive bacterium, which causes sepsis and meningitis in pigs and humans. This review examines the role of known S. suis virulence factors in adhesion and S. suis carbohydrate-based adhesion mechanisms, as well as the inhibition of S. suis adhesion by anti-adhesion compounds in in vitro assays. Carbohydrate-binding specificities of S. suis have been identified, and these studies have shown that many strains recognize Galα1-4Gal-containing oligosaccharides present in host glycolipids. In the era of increasing antibiotic resistance, new means to treat infections are needed. Since microbial adhesion to carbohydrates is important to establish disease, compounds blocking adhesion could be an alternative to antibiotics. The use of oligosaccharides as drugs is generally hampered by their relatively low affinity (micromolar) to compete with multivalent binding to host receptors. However, screening of a library of chemically modified Galα1-4Gal derivatives has identified compounds that inhibit S. suis adhesion in nanomolar range. Also, design of multivalent Galα1-4Gal-containing dendrimers has resulted in a significant increase of the inhibitory potency of the disaccharide. The S. suis adhesin binding to Galα1-4Gal-oligosaccharides, Streptococcal adhesin P (SadP), was recently identified. It has a Galα1-4Gal-binding N-terminal domain and a C-terminal LPNTG-motif for cell wall anchoring. The carbohydrate-binding domain has no homology to E. coli P fimbrial adhesin, which suggests that these Gram-positive and Gram-negative bacterial adhesins recognizing the same receptor have evolved by convergent evolution. SadP adhesin may represent a promising target for the design of anti-adhesion ligands for the prevention and treatment of S. suis infections. PMID:24833053

Mangiferin stimulates carbohydrate oxidation and protects against metabolic disorders induced by high-fat diets.

PubMed

Apontes, Pasha; Liu, Zhongbo; Su, Kai; Benard, Outhiriaradjou; Youn, Dou Y; Li, Xisong; Li, Wei; Mirza, Raihan H; Bastie, Claire C; Jelicks, Linda A; Pessin, Jeffrey E; Muzumdar, Radhika H; Sauve, Anthony A; Chi, Yuling

2014-11-01

Excessive dietary fat intake causes systemic metabolic toxicity, manifested in weight gain, hyperglycemia, and insulin resistance. In addition, carbohydrate utilization as a fuel is substantially inhibited. Correction or reversal of these effects during high-fat diet (HFD) intake is of exceptional interest in light of widespread occurrence of diet-associated metabolic disorders in global human populations. Here we report that mangiferin (MGF), a natural compound (the predominant constituent of Mangifera indica extract from the plant that produces mango), protected against HFD-induced weight gain, increased aerobic mitochondrial capacity and thermogenesis, and improved glucose and insulin profiles. To obtain mechanistic insight into the basis for these effects, we determined that mice exposed to an HFD combined with MGF exhibited a substantial shift in respiratory quotient from fatty acid toward carbohydrate utilization. MGF treatment significantly increased glucose oxidation in muscle of HFD-fed mice without changing fatty acid oxidation. These results indicate that MGF redirects fuel utilization toward carbohydrates. In cultured C2C12 myotubes, MGF increased glucose and pyruvate oxidation and ATP production without affecting fatty acid oxidation, confirming in vivo and ex vivo effects. Furthermore, MGF inhibited anaerobic metabolism of pyruvate to lactate but enhanced pyruvate oxidation. A key target of MGF appears to be pyruvate dehydrogenase, determined to be activated by MGF in a variety of assays. These findings underscore the therapeutic potential of activation of carbohydrate utilization in correction of metabolic syndrome and highlight the potential of MGF to serve as a model compound that can elicit fuel-switching effects. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

Carbohydrate digestion in Lutzomyia longipalpis' larvae (Diptera - Psychodidae).

PubMed

Vale, Vladimir F; Moreira, Bruno H; Moraes, Caroline S; Pereira, Marcos H; Genta, Fernando A; Gontijo, Nelder F

2012-10-01

Lutzomyia longipalpis is the principal species of phlebotomine incriminated as vector of Leishmania infantum, the etiological agent of visceral leishmaniasis in the Americas. Despite its importance as vector, almost nothing related to the larval biology, especially about its digestive system has been published. The objective of the present study was to obtain an overview of carbohydrate digestion by the larvae. Taking in account that phlebotomine larvae live in the soil rich in decaying materials and microorganisms we searched principally for enzymes capable to hydrolyze carbohydrates present in this kind of substrate. The principal carbohydrases encountered in the midgut were partially characterized. One of them is a α-amylase present in the anterior midgut. It is probably involved with the digestion of glycogen, the reserve carbohydrate of fungi. Two other especially active enzymes were present in the posterior midgut, a membrane bound α-glucosidase and a membrane bound trehalase. The first, complete the digestion of glycogen and the other probably acts in the digestion of trehalose, a carbohydrate usually encountered in microorganisms undergoing hydric stress. In a screening done with the use of p-nitrophenyl-derived substrates other less active enzymes were also observed in the midgut. A general view of carbohydrate digestion in L. longipalpis was presented. Our results indicate that soil microorganisms appear to be the main source of nutrients for the larvae. Copyright © 2012 Elsevier Ltd. All rights reserved.

Genomic Reconstruction of Carbohydrate Utilization Capacities in Microbial-Mat Derived Consortia

PubMed Central

Leyn, Semen A.; Maezato, Yukari; Romine, Margaret F.; Rodionov, Dmitry A.

2017-01-01

Two nearly identical unicyanobacterial consortia (UCC) were previously isolated from benthic microbial mats that occur in a heliothermal saline lake in northern Washington State. Carbohydrates are a primary source of carbon and energy for most heterotrophic bacteria. Since CO2 is the only carbon source provided, the cyanobacterium must provide a source of carbon to the heterotrophs. Available genomic sequences for all members of the UCC provide opportunity to investigate the metabolic routes of carbon transfer between autotroph and heterotrophs. Here, we applied a subsystem-based comparative genomics approach to reconstruct carbohydrate utilization pathways and identify glycohydrolytic enzymes, carbohydrate transporters and pathway-specific transcriptional regulators in 17 heterotrophic members of the UCC. The reconstructed metabolic pathways include 800 genes, near a one-fourth of which encode enzymes, transporters and regulators with newly assigned metabolic functions resulting in discovery of novel functional variants of carbohydrate utilization pathways. The in silico analysis revealed the utilization capabilities for 40 carbohydrates and their derivatives. Two Halomonas species demonstrated the largest number of sugar catabolic pathways. Trehalose, sucrose, maltose, glucose, and beta-glucosides are the most commonly utilized saccharides in this community. Reconstructed regulons for global regulators HexR and CceR include central carbohydrate metabolism genes in the members of Gammaproteobacteria and Alphaproteobacteria, respectively. Genomics analyses were supplemented by experimental characterization of metabolic phenotypes in four isolates derived from the consortia. Measurements of isolate growth on the defined medium supplied with individual carbohydrates confirmed most of the predicted catabolic phenotypes. Not all consortia members use carbohydrates and only a few use complex polysaccharides suggesting a hierarchical carbon flow from cyanobacteria to

Determination of carbohydrates in medicinal plants--comparison between TLC, mf-MELDI-MS and GC-MS.

PubMed

Qureshi, Muhammad Nasimullah; Stecher, Guenther; Sultana, Tahira; Abel, Gudrun; Popp, Michael; Bonn, Guenther K

2011-01-01

Quality control in the pharmaceutical and phytopharmaceutical industries requires fast and reliable methods for the analysis of raw materials and final products. This study evaluates different analytical approaches in order to recognise the most suitable technique for the analysis of carbohydrates in herbal drug preparations. The specific focus of the study is on thin-layer chromatography (TLC), gas chromatography (GC), and a newly developed mass spectrometric method, i.e. matrix free material enhanced laser desorption/ionisation time of flight mass spectrometry (mf-MELDI-MS). Samples employed in the study were standards and microwave-assisted water extracts from Quercus. TLC analysis proved the presence of mono-, di- and trisaccharides within the biological sample and hinted at the existence of an unknown carbohydrate of higher oligomerisation degree. After evaluation of different derivatisation techniques, GC-MS confirmed data obtained via TLC for mono- to trisaccharides, delivering additionally quantified values under a considerable amount of time. A carbohydrate of higher oligomerisation degree could not be found. The application of mf-MELDI-MS further confirmed the presence of carbohydrates up to trisaccharides, also hinting at the presence of a form of tetrasaccharide. Besides this information, mf-MELDI-MS delivered further data about other substances present in the extract. Quantitative determination resulted in 1.750, 1.736 and 0.336 mg/mL for glucose, sucrose and raffinose respectively. Evaluation of all three techniques employed, clearly proved the heightened performance of mf-MELDI-MS for the qualitative analysis of complex mixtures, as targets do not need modification and analysis requires only a few minutes. In addition, GC-MS is suitable for quantitative analysis. Copyright © 2011 John Wiley & Sons, Ltd.

Low-carbohydrate diet induces metabolic depression: a possible mechanism to conserve glycogen.

PubMed

Winwood-Smith, Hugh S; Franklin, Craig E; White, Craig R

2017-10-01

Long-term studies have found that low-carbohydrate diets are more effective for weight loss than calorie-restricted diets in the short term but equally or only marginally more effective in the long term. Low-carbohydrate diets have been linked to reduced glycogen stores and increased feelings of fatigue. We propose that reduced physical activity in response to lowered glycogen explains the diminishing weight loss advantage of low-carbohydrate compared with low-calorie diets over longer time periods. We explored this possibility by feeding adult Drosophila melanogaster a standard or a low-carbohydrate diet for 9 days and measured changes in metabolic rate, glycogen stores, activity, and body mass. We hypothesized that a low-carbohydrate diet would cause a reduction in glycogen stores, which recover over time, a reduction in physical activity, and an increase in resting metabolic rate. The low-carbohydrate diet reduced glycogen stores, which recovered over time. Activity was unaffected by diet, but metabolic rate was reduced, in the low-carbohydrate group. We conclude that metabolic depression could explain the decreased effectiveness of low-carbohydrate diets over time and recommend further investigation of long-term metabolic effects of dietary interventions and a greater focus on physiological plasticity within the study of human nutrition. Copyright © 2017 the American Physiological Society.

Carbohydrates as T-cell antigens with implications in health and disease.

PubMed

Sun, Lina; Middleton, Dustin R; Wantuch, Paeton L; Ozdilek, Ahmet; Avci, Fikri Y

2016-10-01

Glycosylation is arguably the most ubiquitous post-translational modification on proteins in microbial and mammalian cells. During the past few years, there has been intensive research demonstrating that carbohydrates, either in pure forms or in conjunction with proteins or lipids, evoke and modulate adaptive immune responses. We now know that carbohydrates can be directly recognized by T cells or participate in T-cell stimulation as components of T-cell epitopes. T-cell recognition of carbohydrate antigens takes place via their presentation by major histocompatibility complex pathways on antigen-presenting cells. In this review, we summarize studies on carbohydrates as T-cell antigens modulating adaptive immune responses. Through discussion of glycan-containing antigens, such as glycoproteins, glycolipids, zwitterionic polysaccharides and carbohydrate-based glycoconjugate vaccines, we will illustrate the key molecular and cellular interactions between carbohydrate antigens and T cells and the implications of these interactions in health and disease. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Digestible and indigestible carbohydrates: interactions with postprandial lipid metabolism.

PubMed

Lairon, Denis; Play, Barbara; Jourdheuil-Rahmani, Dominique

2007-04-01

The balance between fats and carbohydrates in the human diet is still a matter of very active debate. Indeed, the processing of ordinary mixed meals involves complex processes within the lumen of the upper digestive tract for digestion, in the small intestine mucosa for absorption and resecretion, and in peripheral tissues and in the circulation for final handling. The purpose of this review is to focus on available knowledge on the interactions of digestible or indigestible carbohydrates with lipid and lipoprotein metabolism in the postprandial state. The observations made in humans after test meals are reported and interpreted in the light of recent findings on the cellular and molecular levels regarding possible interplays between carbohydrates and lipid moieties in some metabolic pathways. Digestible carbohydrates, especially readily digestible starches or fructose, have been shown to exacerbate and/or delay postprandial lipemia, whereas some fiber sources can lower it. While interactions between dietary fibers and the process of lipid digestion and absorption have been studied mainly in the last decades, recent studies have shown that dietary carbohydrate moieties (e.g., glucose) can stimulate the intestinal uptake of cholesterol and lipid resecretion. In addition to the well-known glucose/fructose transporters, a number of transport proteins have recently been involved in intestinal lipid processing, whose implications in such interactions are discussed. The potential importance of postprandial insulinemia in these processes is also evaluated in the light of recent findings. The interactions of carbohydrates and lipid moieties in the postprandial state may result from both acute and chronic effects, both at transcriptional and posttranscriptional levels.

Why use DFT methods in the study of carbohydrates?

USDA-ARS?s Scientific Manuscript database

The recent advances in density functional theory (DFT) and computer technology allow us to study systems with more than 100 atoms routinely. This makes it feasible to study large carbohydrate molecules via quantum mechanical methods, whereas in the past, studies of carbohydrates were restricted to ...

The Effects of Marine Carbohydrates and Glycosylated Compounds on Human Health

PubMed Central

Kang, Hee-Kyoung; Seo, Chang Ho; Park, Yoonkyung

2015-01-01

Marine organisms have been recognized as a valuable source of bioactive compounds with industrial and nutraceutical potential. Recently, marine-derived carbohydrates, including polysaccharides and low molecular weight glycosylated oligosaccharides, have attracted much attention because of their numerous health benefits. Moreover, several studies have reported that marine carbohydrates exhibit various biological activities, including antioxidant, anti-infection, anticoagulant, anti-inflammatory, and anti-diabetic effects. The present review discusses the potential industrial applications of bioactive marine carbohydrates for health maintenance and disease prevention. Furthermore, the use of marine carbohydrates in food, cosmetics, agriculture, and environmental protection is discussed. PMID:25785562

UTILIZATION OF CARBOHYDRATES AND POLYHYDRIC ALCOHOLS BY MYCOBACTERIUM TUBERCULOSIS

PubMed Central

Sweeney, Edward E.; Jann, Gregory J.

1962-01-01

Sweeney, Edward E. (University of California, Los Angeles) and Gregory J. Jann. Utilization of carbohydrates and polyhydric alcohols by Mycobacterium tuberculosis. J. Bacteriol. 84:459–465. 1962.—A new procedure, using a massive inoculum and nongrowth basal medium, was employed for testing carbohydrate and polyhydric alcohol utilization by human tubercle bacilli. A positive reaction was represented by acidification of the test medium rather than by growth, which was the criterion for carbohydrate utilization in studies by earlier workers. The new procedure was both more sensitive and more rapid than growth techniques; results were obtained within days, compared to weeks or months required for growth testing. The massive-inoculum technique may be applied to compounds other than carbohydrates and polyhydric alcohols, and is a sensitive means of detecting changes wrought by various chemical and physical agents upon the metabolism of tubercle bacilli. Three H37Rv strains and six strains of human tubercle bacilli freshly isolated from patients were tested with 21 carbohydrates and polyhydric alcohols. All nine strains gave strong positive reactions for glucose and glycerol, and usually weak positive reactions for ribose and sorbose. Five of the nine strains were trehalose positive, and six (all fresh patient isolates) of the nine were mannose positive. PMID:13979661

Effects of front-surface target structures on properties of relativistic laser-plasma electrons.

PubMed

Jiang, S; Krygier, A G; Schumacher, D W; Akli, K U; Freeman, R R

2014-01-01

We report the results of a study of the role of prescribed geometrical structures on the front of a target in determining the energy and spatial distribution of relativistic laser-plasma electrons. Our three-dimensional particle-in-cell simulation studies apply to short-pulse, high-intensity laser pulses, and indicate that a judicious choice of target front-surface geometry provides the realistic possibility of greatly enhancing the yield of high-energy electrons while simultaneously confining the emission to narrow (<5°) angular cones.

Does preoperative oral carbohydrate reduce hospital stay? A randomized trial.

PubMed

Webster, Joan; Osborne, Sonya Ranee; Gill, Richard; Chow, Carina Faran Kalan; Wallin, Siobhan; Jones, Lee; Tang, Annie

2014-02-01

Oral carbohydrate-rich fluids are used preoperatively to improve postoperative recovery, but their effectiveness for reducing length of hospital stay is uncertain. We assessed the effectiveness of preoperative loading with carbohydrates on the postoperative outcomes of 44 patients scheduled for elective colorectal surgery who were randomly allocated to a carbohydrate-rich fluid group or a usual care group during their preadmission clinic visit. Our primary outcome was the time patients required to be ready for discharge. Patients in the control group spent an average of 4.3 days (95% confidence interval [CI], 3.2-5.7) in the hospital and patients in the carbohydrate-rich fluid group spent 4.1 days (95% CI, 3.2-5.4) in the hospital until they met discharge criteria (P = .824). We found that the safety of administering preoperative oral carbohydrate-rich fluids is supported, but we were unable to confirm or refute the benefit of this treatment regimen for contributing to shorter hospital stays after elective colorectal surgery. Copyright © 2014 AORN, Inc. Published by Elsevier Inc. All rights reserved.

Structure and properties of optical-discharge plasma in CO2-laser beam near target surface

NASA Astrophysics Data System (ADS)

Danshchikov, Ye. V.; Dymshakov, V. A.; Lebedev, F. V.; Ryazanov, A. V.

1986-05-01

An experimental study of optical-discharge plasma in a CO2-laser beam at a target surface was made for the purpose of exploring the not yet understood role of this plasma in the laser-target interaction process. Such a plasma was produced by means of a quasi-continuous CO2-laser with an unstable resonator, its power being maintained constant for 1 ms periods. Its radiation was focused on the surfaces of thick and seeding thin Al, Ti, and Ta targets inclined at an approximately 70 deg. angle to the beam, inside a hermetic chamber containing air, argon, or helium under atmospheric pressure. The radiation intensity distribution over the focal plane and the nearest caustic surface in the laser beam was measured along with the plasma parameters, the latter by the methods of spectral analysis and photoelectric recording. The instrumentation for this purpose included an MDR-3 monochromator with an entrance slit, a double electron-optical converter, a memory oscillograph, and an SI-10-30 ribbon lamp as radiation reference standard. The results yielded integral diametral intensity distributions of the emission lines Ti-II (457.2 nm), Ti-I (464 nm), Ar-II (462 nm), radial and axial temperature profiles of optical discharge in metal vapor in surrounding gas, and the radial temperature profile of irradiated metal surface at successive instants of time. The results reveal marked differences between the structures and the properties of optical-discharge plasma in metal vapor and in surrounding gas, optical discharge in the former being characterized by localization within the laser beam and optical discharge in the latter being characterized by a drift away from the target.

Co-occurrence of carbohydrate malabsorption and primary epiploic appendagitis

PubMed Central

Schnedl, Wolfgang J; Kalmar, Peter; Mangge, Harald; Krause, Robert; Wallner-Liebmann, Sandra J

2015-01-01

Unspecific abdominal complaints including bloating and irregular bowel movements may be caused by carbohydrate malabsorption syndromes, e.g., lactose and fructose malabsorption. These symptoms were investigated with hydrogen (H2) breath tests and correlated to carbohydrate malabsorption. During performing these H2-breath tests the patient presented with an acute, localized, non-migratory pain in the left lower abdominal quadrant. Primary epiploic appendagitis is a rare cause of abdominal acute or subacute complaints and diagnosis of primary epiploic appendagitis (PEA) is made when computed tomography reveals a characteristic lesion. We report on a patient with co-occurrence of lactose and fructose malabsorption, which was treated successfully with a diet free of culprit carbohydrates, with PEA recovering without medication or surgical treatment within few days. Since the abdominal unspecific symptoms had been present for months, they appeared not to be correlated to the acute localized abdominal pain, therefore we speculate on a random co-occurrence of combined carbohydrate malabsorption and PEA. PMID:26401090

Pattern of dietary carbohydrate intake among urbanized adult Nigerians

PubMed Central

AKAROLO-ANTHONY, SALLY N.; ODUBORE, FOLAKE O.; YILME, SUSAN; ARAGBADA, OMOLOLA; ODONYE, GEORGE; HU, FRANK; WILLETT, WALTER; SPIEGELMAN, DONNA; ADEBAMOWO, CLEMENT A.

2013-01-01

As the nutrition transition continues in Africa, it is crucial to identify population-specific dietary patterns. Healthy diets may then be promoted for prevention and alleviation of the chronic disease burden associated with nutrition. Using a semi-quantitate food frequency questionnaire, we conducted a cross-sectional study and computed the proportions of foods commonly consumed, and collected data on anthropometric characteristics. The median total energy intake per day from these carbohydrate sources was 1034 kcal (interquartile range (IOR) 621.5–1738.6 kcal). The main carbohydrate food eaten was rice (48.6%) followed by fufu (30.5%) and bread (13.1%). The prevalence of overweight and obesity was 63%, and 73% of the women in the study were either overweight or obese compared to 56% of men. Our study showed that parboiled long grain white rice is now the most commonly consumed carbohydrate by urbanized Nigerians. Other traditional carbohydrate foods are still consumed frequently and remain quite popular. PMID:23198770

Biophysical studies on calcium and carbohydrate binding to carbohydrate recognition domain of Gal/GalNAc lectin from Entamoeba histolytica: insights into host cell adhesion.

PubMed

Yadav, Rupali; Verma, Kuldeep; Chandra, Mintu; Mukherjee, Madhumita; Datta, Sunando

2016-09-01

Entamoeba histolytica, an enteric parasite expresses a Gal/GalNAc-specific lectin that contributes to its virulence by establishing adhesion to host cell. In this study, carbohydrate recognition domain of Hgl (EhCRD) was purified and biophysical studies were conducted to understand the thermodynamic basis of its binding to carbohydrate and Ca(++) Here, we show that carbohydrate recognition domain (CRD) of the lectin binds to calcium through DPN motif. To decipher the role of calcium in carbohydrate binding and host cell adhesion, biophysical and cell-based studies were carried out. We demonstrated that the presence of the cation neither change the affinity of the lectin for carbohydrates nor alters its conformation. Mutation of the calcium-binding motif in EhCRD resulted in complete loss of ability to bind calcium but retained its affinity for carbohydrates. Purified EhCRD significantly diminished adhesion of the amebic trophozoites to Chinese Hamster Ovary (CHO) cells as well as triggered red blood cell agglutination. The calcium-binding defective mutant abrogated amebic adhesion to CHO cells similar to the wild-type protein, but it failed to agglutinate RBCs suggesting a differential role of the cation in these two processes. This study provides the first molecular description of the role of calcium in Gal/GalNAc mediated host cell adhesion. © The Authors 2016. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Molecular Simulations of Carbohydrates with a Fucose-Binding Burkholderia ambifaria Lectin Suggest Modulation by Surface Residues Outside the Fucose-Binding Pocket

PubMed Central

Dingjan, Tamir; Imberty, Anne; Pérez, Serge; Yuriev, Elizabeth; Ramsland, Paul A.

2017-01-01

Burkholderia ambifaria is an opportunistic respiratory pathogen belonging to the Burkholderia cepacia complex, a collection of species responsible for the rapidly fatal cepacia syndrome in cystic fibrosis patients. A fucose-binding lectin identified in the B. ambifaria genome, BambL, is able to adhere to lung tissue, and may play a role in respiratory infection. X-ray crystallography has revealed the bound complex structures for four fucosylated human blood group epitopes (blood group B, H type 1, H type 2, and Lex determinants). The present study employed computational approaches, including docking and molecular dynamics (MD), to extend the structural analysis of BambL-oligosaccharide complexes to include four additional blood group saccharides (A, Lea, Leb, and Ley) and a library of blood-group-related carbohydrates. Carbohydrate recognition is dominated by interactions with fucose via a hydrogen-bonding network involving Arg15, Glu26, Ala38, and Trp79 and a stacking interaction with Trp74. Additional hydrogen bonds to non-fucose residues are formed with Asp30, Tyr35, Thr36, and Trp74. BambL recognition is dominated by interactions with fucose, but also features interactions with other parts of the ligands that may modulate specificity or affinity. The detailed computational characterization of the BambL carbohydrate-binding site provides guidelines for the future design of lectin inhibitors. PMID:28680402

Structural basis of carbohydrate recognition by lectin II from Ulex europaeus, a protein with a promiscuous carbohydrate-binding site.

PubMed

Loris, R; De Greve, H; Dao-Thi, M H; Messens, J; Imberty, A; Wyns, L

2000-08-25

Protein-carbohydrate interactions are the language of choice for inter- cellular communication. The legume lectins form a large family of homologous proteins that exhibit a wide variety of carbohydrate specificities. The legume lectin family is therefore highly suitable as a model system to study the structural principles of protein-carbohydrate recognition. Until now, structural data are only available for two specificity families: Man/Glc and Gal/GalNAc. No structural data are available for any of the fucose or chitobiose specific lectins. The crystal structure of Ulex europaeus (UEA-II) is the first of a legume lectin belonging to the chitobiose specificity group. The complexes with N-acetylglucosamine, galactose and fucosylgalactose show a promiscuous primary binding site capable of accommodating both N-acetylglucos amine or galactose in the primary binding site. The hydrogen bonding network in these complexes can be considered suboptimal, in agreement with the low affinities of these sugars. In the complexes with chitobiose, lactose and fucosyllactose this suboptimal hydrogen bonding network is compensated by extensive hydrophobic interactions in a Glc/GlcNAc binding subsite. UEA-II thus forms the first example of a legume lectin with a promiscuous binding site and illustrates the importance of hydrophobic interactions in protein-carbohydrate complexes. Together with other known legume lectin crystal structures, it shows how different specificities can be grafted upon a conserved structural framework. Copyright 2000 Academic Press.

Characterization of carbohydrates in rainwater from the southeastern North Carolina.

PubMed

Mullaugh, Katherine M; Byrd, Jade N; Avery, G Brooks; Mead, Ralph N; Willey, Joan D; Kieber, Robert J

2014-07-01

Carbohydrates have been widely reported in atmospheric aerosols, but have not previously been quantified in rainwater. We have identified and quantified a series of 11 specific compounds including monosaccharides (glucose, fructose, arabinose, galactose and pinitol), disaccharides (sucrose and trehalose), sugar alcohols (arabitol, dulcitol and mannitol) and the anhydrosaccharide levoglucosan. Rainwater analyzed in this study includes 52 distinct precipitation events in Wilmington, NC between June 2011 and October 2012. Our analysis indicates carbohydrates typically contribute <1% of total dissolved organic carbon in rain, but can account for as much as 10-35% during periods of high pollen or local fires. Concentrations of individual carbohydrates reached as high as 5.8 μM, with glucose and sucrose typically being the predominant species. The distribution of carbohydrates exhibited a distinct seasonal pattern, with higher concentrations of most carbohydrates, especially sucrose, in spring and summer, driven primarily by increased biogenic inputs during the growing season. Concentrations of carbohydrates were an order of magnitude higher in storms of terrestrial origin compared to marine events, further supporting a terrestrial biogenic origin of most species. Sequential sampling of Hurricane Irene showed significant quantities of carbohydrates present at the end of the storm when air mass back trajectories traversed over land. The highest level of levoglucosan, a compound associated with biomass burning, was detected in rain with an air mass back trajectory that traveled over a region affected by wildfires. When compared to aerosol concentrations reported by others, the sugar concentrations in rain demonstrate wet deposition is an important removal mechanism of this water-soluble and bioavailable fraction of atmospheric particulate organic matter. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pharmaceutical, cosmeceutical, and traditional applications of marine carbohydrates.

PubMed

Ahmed, Abdul Bakrudeen Ali; Adel, Mohaddeseh; Karimi, Pegah; Peidayesh, Mahvash

2014-01-01

Marine carbohydrates are most important organic molecules made by photosynthetic organisms. It is very essential for humankind: the role in being an energy source for the organism and they are considered as an important dissolve organic compound (DOC) in marine environment's sediments. Carbohydrates found in different marine environments in different concentrations. Polysaccharides of carbohydrates play an important role in various fields such as pharmaceutical, food production, cosmeceutical, and so on. Marine organisms are good resources of nutrients, and they are rich carbohydrate in sulfated polysaccharide. Seaweeds (marine microalgae) are used in different pharmaceutical industries, especially in pharmaceutical compound production. Seaweeds have a significant amount of sulfated polysaccharides, which are used in cosmeceutical industry, besides based on the biological applications. Since then, traditional people, cosmetics products, and pharmaceutical applications consider many types of seaweed as an important organism used in food process. Sulfated polysaccharides containing seaweed have potential uses in the blood coagulation system, antiviral activity, antioxidant activity, anticancer activity, immunomodulating activity, antilipidepic activity, etc. Some species of marine organisms are rich in polysaccharides such as sulfated galactans. Various polysaccharides such as agar and alginates, which are extracted from marine organisms, have several applications in food production and cosmeceutical industries. Due to their high health benefits, compound-derived extracts of marine polysaccharides have various applications and traditional people were using them since long time ago. In the future, much attention is supposed to be paid to unraveling the structural, compositional, and sequential properties of marine carbohydrate as well. © 2014 Elsevier Inc. All rights reserved.

Hearing Loss, Dizziness, and Carbohydrate Metabolism

PubMed Central

Albernaz, Pedro L. Mangabeira

2015-01-01

Introduction  Metabolic activity of the inner ear is very intense, and makes it sensitive to changes in the body homeostasis. This study involves a group of patients with inner ear disorders related to carbohydrate metabolism disturbances, including hearing loss, tinnitus, dizziness, and episodes of vertigo. Objectives  To describe the symptoms of metabolic inner ear disorders and the examinations required to establish diagnoses. These symptoms are often the first to allow for an early diagnosis of metabolic disorders and diabetes. Methods  Retrospective study of 376 patients with inner ear symptoms suggestive of disturbances of carbohydrate metabolism. The authors present patientś clinical symptoms and clinical evaluations, with emphasis on the glucose and insulin essays. Results  Authors based their conclusions on otolaryngological findings, diagnostic procedures and treatment principles. They found that auditory and vestibular symptoms usually occur prior to other manifestations of metabolic changes, leading to an early diagnosis of hyperinsulinemia, intestinal sugar malabsorption or diabetes. Previously undiagnosed diabetes mellitus type II was found in 39 patients. Conclusions  The identification of carbohydrate metabolism disturbances is important not only to minimize the patients' clinical symptoms, but also to help maintain their general health. PMID:27413410

Effects of carbohydrates on satiety: differences between liquid and solid food.

PubMed

Pan, An; Hu, Frank B

2011-07-01

To examine the satiety effect of carbohydrates with a focus on the comparison of liquid and solid food and their implications for energy balance and weight management. A number of studies have examined the role of dietary fiber, whole grains, and glycemic index or glycemic load on satiety and subsequent energy intake, but results remain inconclusive. Intake of liquid carbohydrates, particularly sugar-sweetened beverages, has increased considerably across the globe in recent decades in both adolescents and adults. In general, liquid carbohydrates produce less satiety compared with solid carbohydrates. Some energy from liquids may be compensated for at subsequent meals but because the compensation is incomplete, it leads to an increase in total long-term energy intake. Recent studies also suggest some potential differential responses of satiety by characteristics of the patients (e.g., race, sex, and body weight status). These differences warrant further research. Satiety is a complex process influenced by a number of properties in food. The physical form (solid vs. liquid) of carbohydrates is an important component that may affect the satiety process and energy intake. Accumulating evidence suggests that liquid carbohydrates generally produce less satiety than solid forms.

Recent Developments in Synthetic Carbohydrate-Based Diagnostics, Vaccines, and Therapeutics.

PubMed

Fernández-Tejada, Alberto; Cañada, F Javier; Jiménez-Barbero, Jesús

2015-07-20

Glycans are everywhere in biological systems, being involved in many cellular events with important implications for medical purposes. Building upon a detailed understanding of the functional roles of carbohydrates in molecular recognition processes and disease states, glycans are increasingly being considered as key players in pharmacological research. On the basis of the important progress recently made in glycochemistry, glycobiology, and glycomedicine, we provide a complete overview of successful applications and future perspectives of carbohydrates in the biopharmaceutical and medical fields. This review highlights the development of carbohydrate-based diagnostics, exemplified by glycan imaging techniques and microarray platforms, synthetic oligosaccharide vaccines against infectious diseases (e.g., HIV) and cancer, and finally carbohydrate-derived therapeutics, including glycomimetic drugs and glycoproteins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface functionalization of liposomes with proteins and carbohydrates for use in anti-cancer applications

NASA Astrophysics Data System (ADS)

Platt, Virginia M.

Liposomes can be used to exploit the altered biology of cancer thereby increasing delivery of liposome-associated anti-cancer drugs. In this dissertation, I explore methods that utilize the unique cancer expression of the polymeric glycosaminoglycan hyaluronan (HA) and the HA receptor CD44 to target liposomes to tumors, using liposomes functionalized with proteins or oligosaccharides on their surface. To make it easier to prepare protein-functionalized liposomes, a non-covalent protein/liposome association method based upon metal chelation/his 6 interaction was devised and characterized. I evaluated non-covalent attachment of the prodrug converting enzyme yeast cytosine deaminase, the far-red fluorescent protein mKate, two antigens ovalbumin and the membrane proximal region of an HIV GAG and hyaluronidase, a HA-degrading enzyme. In Chapter 2, I describe the synthesis of hyaluronan-oligosaccharide (HA-O) lipid conjugates and their incorporation into liposomes to target CD44-overexpressing cancer cells. HA-O ligands of defined-length, up to 10 monosaccharides, were attached to lipids via various linkers by reductive amination. The HA-lipids were easily incorporated into liposomes but did not mediate binding of liposomes to CD44 overexpressing cells. In Chapter 3, I evaluate the capacity of tris-NTA-Ni-lipids incorporated within a liposome bilayer to associate with his6-tagged proteins. Tris-NTA-lipids of differing structures and avidities were used to associate yeast cytosine deaminase and mKate to the surface of liposomes. Two tris-NTA-lipids and a mono-NTA lipid associated his-tagged proteins to a 1:1 molar ratio in solution. The proteins remained active while associated with the liposome surface. When challenged in vitro with fetal calf serum, tris-NTA-containing liposomes retained his-tagged proteins longer than mono-NTA. However, the tris-NTA/his6 interaction was found to be in a dynamic state; free yeast cytosine deaminase rapidly competed with pre-bound m

Carbohydrate conjugation through microwave-assisted functionalization of single-walled carbon nanotubes using perfluorophenyl azides.

PubMed

Kong, Na; Shimpi, Manishkumar R; Ramström, Olof; Yan, Mingdi

2015-03-20

Carbohydrate-functionalized single-walled carbon nanotubes (SWNTs) were synthesized using microwave-assisted reaction of perfluorophenyl azide with the nanotubes. The results showed that microwave radiation provides a rapid and effective means to covalently attach carbohydrates to SWNTs, producing carbohydrate-SWNT conjugates for biorecognition. The carbohydrate-functionalized SWNTs were furthermore shown to interact specifically with cognate carbohydrate-specific proteins (lectins), resulting in predicted recognition patterns. The carbohydrate-presenting SWNTs constitute a new platform for sensitive protein- or cell recognition, which pave the way for glycoconjugated carbon nanomaterials in biorecognition applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

3β-Hydroxysterol Δ24-Reductase on the Surface of Hepatitis C Virus-Related Hepatocellular Carcinoma Cells Can Be a Target for Molecular Targeting Therapy

PubMed Central

Saito, Makoto; Takano, Takashi; Nishimura, Tomohiro; Kohara, Michinori; Tsukiyama-Kohara, Kyoko

2015-01-01

In our previous study, we demonstrated that 3β-hydroxysterol Δ24-reductase (DHCR24) was overexpressed in hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC), and that its expression was induced by HCV. Using a monoclonal antibody against DHCR24 (2-152a MAb), we found that DHCR24 was specifically expressed on the surface of HCC cell lines. Based on these findings, we aimed to establish a novel targeting strategy using 2-152a MAb to treat HCV-related HCC. In the present study, we examined the antitumor activity of 2-152a MAb. In the presence of complement, HCC-derived HuH-7 cells were killed by treatment with 2-152a MAb, which was mediated by complement-dependent cytotoxicity (CDC). In addition, the antigen recognition domain of 2-152a MAb was responsible for the unique anti-HCV activity. These findings demonstrate the feasibility of using 2-152a MAb for antibody therapy against HCV-related HCC. In addition, surface DHCR24 on HCC cells exhibited a functional property, agonist-induced internalization. We showed that 2-152a MAb-mediated binding of a cytotoxic agent (a saponin-conjugated secondary antibody) to surface DHCR24 led to significant cytotoxicity. This suggests that surface DHCR24 on HCC cells can function as a carrier for internalization. Therefore, surface DHCR24 could be a valuable target for HCV-related HCC therapy, and 2-152a MAb appears to be useful for this targeted therapy. PMID:25875901

Assessment of personal airborne exposures and surface contamination from x-ray vaporization of beryllium targets at the National Ignition Facility

DOE PAGES

Paik, Samuel Y.; Epperson, Patrick M.; Kasper, Kenneth M.

2017-02-28

Here, this article presents air and surface sampling data collected over the first two years since beryllium was introduced as a target material at the National Ignition Facility. Over this time, 101 experiments with beryllium-containing targets were executed. The data provides an assessment of current conditions in the facility and a baseline for future impacts as new, reduced regulatory limits for beryllium are being proposed by both the Occupational Safety and Health Administration and Department of Energy. This study also investigates how beryllium deposits onto exposed surfaces as a result of x-ray vaporization and the effectiveness of simple decontamination measuresmore » in reducing the amount of removable beryllium from a surface. Based on 1,961 surface wipe samples collected from entrant components (equipment directly exposed to target debris) and their surrounding work areas during routine reconfiguration activities, only one result was above the beryllium release limit of 0.2 µg/100 cm 2 and 27 results were above the analytical reporting limit of 0.01 µg/100 cm 2, for a beryllium detection rate of 1.4%. Surface wipe samples collected from the internal walls of the NIF target chamber, however, showed higher levels of beryllium, with beryllium detected on 73% and 87% of the samples during the first and second target chamber entries (performed annually), respectively, with 23% of the samples above the beryllium release limit during the second target chamber entry. The analysis of a target chamber wall panel exposed during the first 30 beryllium-containing experiments (cumulatively) indicated that 87% of the beryllium contamination remains fixed onto the surface after wet wiping the surface and 92% of the non-fixed contamination was removed by decontaminating the surface using a dry wipe followed by a wet wipe. Personal airborne exposures assessed during access to entrant components and during target chamber entry indicated that airborne beryllium was

Obtaining control of cell surface functionalizations via Pre-targeting and Supramolecular host guest interactions

NASA Astrophysics Data System (ADS)

Rood, Mark T. M.; Spa, Silvia J.; Welling, Mick M.; Ten Hove, Jan Bart; van Willigen, Danny M.; Buckle, Tessa; Velders, Aldrik H.; van Leeuwen, Fijs W. B.

2017-01-01

The use of mammalian cells for therapeutic applications is finding its way into modern medicine. However, modification or “training” of cells to make them suitable for a specific application remains complex. By envisioning a chemical toolbox that enables specific, but straight-forward and generic cellular functionalization, we investigated how membrane-receptor (pre)targeting could be combined with supramolecular host-guest interactions based on β-cyclodextrin (CD) and adamantane (Ad). The feasibility of this approach was studied in cells with membranous overexpression of the chemokine receptor 4 (CXCR4). By combining specific targeting of CXCR4, using an adamantane (Ad)-functionalized Ac-TZ14011 peptide (guest; KD = 56 nM), with multivalent host molecules that entailed fluorescent β-CD-Poly(isobutylene-alt-maleic-anhydride)-polymers with different fluorescent colors and number of functionalities, host-guest cell-surface modifications could be studied in detail. A second set of Ad-functionalized entities enabled introduction of additional surface functionalities. In addition, the attraction between CD and Ad could be used to drive cell-cell interactions. Combined we have shown that supramolecular interactions, that are based on specific targeting of an overexpressed membrane-receptor, allow specific and stable, yet reversible, surface functionalization of viable cells and how this approach can be used to influence the interaction between cells and their surroundings.

21 CFR 172.866 - Synthetic glycerin produced by the hydrogenolysis of carbohydrates.

Code of Federal Regulations, 2011 CFR

2011-04-01

... of carbohydrates. 172.866 Section 172.866 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... produced by the hydrogenolysis of carbohydrates. Synthetic glycerin produced by the hydrogenolysis of carbohydrates may be safely used in food, subject to the provisions of this section: (a) It shall contain not in...

21 CFR 172.866 - Synthetic glycerin produced by the hydrogenolysis of carbohydrates.

Code of Federal Regulations, 2010 CFR

2010-04-01

... of carbohydrates. 172.866 Section 172.866 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... produced by the hydrogenolysis of carbohydrates. Synthetic glycerin produced by the hydrogenolysis of carbohydrates may be safely used in food, subject to the provisions of this section: (a) It shall contain not in...