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Sample records for c-di-gmp pel polysaccharide

  1. c-di-GMP and its Effects on Biofilm Formation and Dispersion: a Pseudomonas Aeruginosa Review.

    Science.gov (United States)

    Ha, Dae-Gon; O'Toole, George A

    2015-04-01

    Since its initial discovery as an allosteric factor regulating cellulose biosynthesis in Gluconacetobacter xylinus, the list of functional outputs regulated by c-di-GMP has grown. We have focused this article on one of these c-di-GMP-regulated processes, namely, biofilm formation in the organism Pseudomonas aeruginosa. The majority of diguanylate cyclases and phosphodiesterases encoded in the P. aeruginosa genome still remain uncharacterized; thus, there is still a great deal to be learned about the link between c-di-GMP and biofilm formation in this microbe. In particular, while a number of c-di-GMP metabolizing enzymes have been identified that participate in reversible and irreversible attachment and biofilm maturation, there is a still a significant knowledge gap regarding the c-di-GMP output systems in this organism. Even for the well-characterized Pel system, where c-di-GMP-mediated transcriptional regulation is now well documented, how binding of c-di-GMP by PelD stimulates Pel production is not understood in any detail. Similarly, c-di-GMP-mediated control of swimming, swarming and twitching also remains to be elucidated. Thus, despite terrific advances in our understanding of P. aeruginosa biofilm formation and the role of c-di-GMP in this process since the last version of this book (indeed there was no chapter on c-di-GMP!) there is still much to learn.

  2. Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Aragón, Isabel M.; Prada-Ramírez, Harold A.; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

  3. Temperature affects c-di-GMP signalling and biofilm formation in Vibrio cholerae.

    Science.gov (United States)

    Townsley, Loni; Yildiz, Fitnat H

    2015-11-01

    Biofilm formation is crucial to the environmental survival and transmission of Vibrio cholerae, the facultative human pathogen responsible for the disease cholera. During its infectious cycle, V. cholerae experiences fluctuations in temperature within the aquatic environment and during the transition between human host and aquatic reservoirs. In this study, we report that biofilm formation is induced at low temperatures through increased levels of the signalling molecule, cyclic diguanylate (c-di-GMP). Strains harbouring in frame deletions of all V. cholerae genes that are predicted to encode diguanylate cyclases (DGCs) or phosphodiesterases (PDEs) were screened for their involvement in low-temperature-induced biofilm formation and Vibrio polysaccharide gene expression. Of the 52 mutants tested, deletions of six DGCs and three PDEs were found to affect these phenotypes at low temperatures. Unlike wild type, a strain lacking all six DGCs did not exhibit a low-temperature-dependent increase in c-di-GMP, indicating that these DGCs are required for temperature modulation of c-di-GMP levels. We also show that temperature modulates c-di-GMP levels in a similar fashion in the Gram-negative pathogen Pseudomonas aeruginosa but not in the Gram-positive pathogen Listeria monocytogenes. This study uncovers the role of temperature in environmental regulation of biofilm formation and c-di-GMP signalling.

  4. Polyphosphate, cyclic AMP, guanosine tetraphosphate, and c-di-GMP reduce in vitro Lon activity

    Science.gov (United States)

    Osbourne, Devon O; Soo, Valerie WC; Konieczny, Igor; Wood, Thomas K

    2014-01-01

    Lon protease is conserved from bacteria to humans and regulates cellular processes by degrading different classes of proteins including antitoxins, transcriptional activators, unfolded proteins, and free ribosomal proteins. Since we found that Lon has several putative cyclic diguanylate (c-di-GMP) binding sites and since Lon binds polyphosphate (polyP) and lipid polysaccharide, we hypothesized that Lon has an affinity for phosphate-based molecules that might regulate its activity. Hence we tested the effect of polyP, cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), guanosine tetraphosphate (ppGpp), c-di-GMP, and GMP on the ability of Lon to degrade α-casein. Inhibition of in vitro Lon activity occurred for polyP, cAMP, ppGpp, and c-di-GMP. We also demonstrated by HPLC that Lon is able to bind c-di-GMP. Therefore, four cell signals were found to regulate the activity of Lon protease. PMID:24874800

  5. Polyphosphate, cyclic AMP, guanosine tetraphosphate, and c-di-GMP reduce in vitro Lon activity.

    Science.gov (United States)

    Osbourne, Devon O; Soo, Valerie W C; Konieczny, Igor; Wood, Thomas K

    2014-01-01

    Lon protease is conserved from bacteria to humans and regulates cellular processes by degrading different classes of proteins including antitoxins, transcriptional activators, unfolded proteins, and free ribosomal proteins. Since we found that Lon has several putative cyclic diguanylate (c-di-GMP) binding sites and since Lon binds polyphosphate (polyP) and lipid polysaccharide, we hypothesized that Lon has an affinity for phosphate-based molecules that might regulate its activity. Hence we tested the effect of polyP, cyclic adenosine monophosphate (cAMP), cyclic guanosine monophosphate (cGMP), guanosine tetraphosphate (ppGpp), c-di-GMP, and GMP on the ability of Lon to degrade α-casein. Inhibition of in vitro Lon activity occurred for polyP, cAMP, ppGpp, and c-di-GMP. We also demonstrated by HPLC that Lon is able to bind c-di-GMP. Therefore, four cell signals were found to regulate the activity of Lon protease.

  6. Characterization of c-di-GMP signaling in Salmonella typhimurium

    OpenAIRE

    Simm, Roger

    2007-01-01

    Signal transduction via cyclic nucleotides is a general mechanism utilized by cells from all kingdoms of life. Identification of cyclic diguanosine monophosphate (c-di-GMP) as an allosteric activator of the cellulose synthase in Gluconacetobacter xylinus 20 years ago, paved the way for the discovery of a novel general signalling system which is unique to bacteria. In this thesis, the c-di-GMP signalling network leading to the formation of a biofilm behavior in Salmonella...

  7. Optimization of RNA-based c-di-GMP fluorescent sensors through tuning their structural modules.

    Science.gov (United States)

    Inuzuka, Saki; Matsumura, Shigeyoshi; Ikawa, Yoshiya

    2016-08-01

    Cyclic diguanylate (c-di-GMP) is a second messenger of bacteria and its detection is an important issue in basic and applied microbiology. As c-di-GMP riboswitch ligand-binding domains (aptamer domains) capture c-di-GMP with high affinity and selectivity, they are promising platforms for the development of RNA-based c-di-GMP sensors. We analyzed two previously reported c-di-GMP sensor RNAs derived from the Vc2 riboswitch. We also designed and tested their variants, some of which showed improved properties as RNA-based c-di-GMP sensors.

  8. The absence of the Pseudomonas aeruginosa OprF protein leads to increased biofilm formation through variation in c-di-GMP level.

    Science.gov (United States)

    Bouffartigues, Emeline; Moscoso, Joana A; Duchesne, Rachel; Rosay, Thibaut; Fito-Boncompte, Laurène; Gicquel, Gwendoline; Maillot, Olivier; Bénard, Magalie; Bazire, Alexis; Brenner-Weiss, Gerald; Lesouhaitier, Olivier; Lerouge, Patrice; Dufour, Alain; Orange, Nicole; Feuilloley, Marc G J; Overhage, Joerg; Filloux, Alain; Chevalier, Sylvie

    2015-01-01

    OprF is the major outer membrane porin in bacteria belonging to the Pseudomonas genus. In previous studies, we have shown that OprF is required for full virulence expression of the opportunistic pathogen Pseudomonas aeruginosa. Here, we describe molecular insights on the nature of this relationship and report that the absence of OprF leads to increased biofilm formation and production of the Pel exopolysaccharide. Accordingly, the level of c-di-GMP, a key second messenger in biofilm control, is elevated in an oprF mutant. By decreasing c-di-GMP levels in this mutant, both biofilm formation and pel gene expression phenotypes were restored to wild-type levels. We further investigated the impact on two small RNAs, which are associated with the biofilm lifestyle, and found that expression of rsmZ but not of rsmY was increased in the oprF mutant and this occurs in a c-di-GMP-dependent manner. Finally, the extracytoplasmic function (ECF) sigma factors AlgU and SigX displayed higher activity levels in the oprF mutant. Two genes of the SigX regulon involved in c-di-GMP metabolism, PA1181 and adcA (PA4843), were up-regulated in the oprF mutant, partly explaining the increased c-di-GMP level. We hypothesized that the absence of OprF leads to a cell envelope stress that activates SigX and results in a c-di-GMP elevated level due to higher expression of adcA and PA1181. The c-di-GMP level can in turn stimulate Pel synthesis via increased rsmZ sRNA levels and pel mRNA, thus affecting Pel-dependent phenotypes such as cell aggregation and biofilm formation. This work highlights the connection between OprF and c-di-GMP regulatory networks, likely via SigX (ECF), on the regulation of biofilm phenotypes.

  9. Endo-S-c-di-GMP Analogues-Polymorphism and Binding Studies with Class I Riboswitch

    Directory of Open Access Journals (Sweden)

    Herman O. Sintim

    2012-11-01

    Full Text Available C-di-GMP, a cyclic guanine dinucleotide, has been shown to regulate biofilm formation as well as virulence gene expression in a variety of bacteria. Analogues of c-di-GMP have the potential to be used as chemical probes to study c-di-GMP signaling and could even become drug leads for the development of anti-biofilm compounds. Herein we report the synthesis and biophysical studies of a series of c-di-GMP analogues, which have both phosphate and sugar moieties simultaneously modified (called endo-S-c-di-GMP analogues. We used computational methods to predict the relative orientation of the guanine nucleobases in c-di-GMP and analogues. DOSY NMR of the endo-S-c-di-GMP series showed that the polymorphism of c-di-GMP can be tuned with conservative modifications to the phosphate and sugar moieties (conformational steering. Binding studies with Vc2 RNA (a class I c-di-GMP riboswitch revealed that conservative modifications to the phosphate and 2'-positions of c-di-GMP dramatically affected binding to class I riboswitch.

  10. C-di-GMP regulates antimicrobial peptide resistance in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Chua, Song Lin; Tan, Sean Yang-Yi; Rybtke, Morten Theil

    2013-01-01

    Bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger which controls the life styles of many bacteria. A high intracellular level of c-di-GMP induces a biofilm lifestyle, whereas a low intracellular level of c-di-GMP stimulates dispersal of biofilms and promotes a plankto......Bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) is an intracellular second messenger which controls the life styles of many bacteria. A high intracellular level of c-di-GMP induces a biofilm lifestyle, whereas a low intracellular level of c-di-GMP stimulates dispersal of biofilms and promotes...... a planktonic lifestyle. Here, we used expression of different reporters to show that planktonic cells (PCells), biofilm cells (BCells) and cells dispersed from biofilms (DCells) had distinct intracellular c-di-GMP levels. Proteomics analysis showed that the low intracellular c-di-GMP level of DCells induced...... the expression of proteins required for the virulence and development of antimicrobial peptide resistance in P. aeruginosa. In accordance, P. aeruginosa cells with low c-di-GMP levels were found to be more resistant to colistin than P. aeruginosa cells with high c-di-GMP levels. This contradicts the current...

  11. Structural Basis of Ligand Binding by a C-di-GMP Riboswitch

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Lipchock, S; Ames, T; Wang, J; Breaker, R; Strobel, S

    2009-01-01

    The second messenger signaling molecule bis-(3{prime}-5{prime})-cyclic dimeric guanosine monophosphate (c-di-GMP) regulates many processes in bacteria, including motility, pathogenesis and biofilm formation. c-di-GMP-binding riboswitches are important downstream targets in this signaling pathway. Here we report the crystal structure, at 2.7 {angstrom} resolution, of a c-di-GMP riboswitch aptamer from Vibrio cholerae bound to c-di-GMP, showing that the ligand binds within a three-helix junction that involves base-pairing and extensive base-stacking. The symmetric c-di-GMP is recognized asymmetrically with respect to both the bases and the backbone. A mutant aptamer was engineered that preferentially binds the candidate signaling molecule c-di-AMP over c-di-GMP. Kinetic and structural data suggest that genetic regulation by the c-di-GMP riboswitch is kinetically controlled and that gene expression is modulated through the stabilization of a previously unidentified P1 helix, illustrating a direct mechanism for c-di-GMP signaling.

  12. Trigger phosphodiesterases as a novel class of c-di-GMP effector proteins.

    Science.gov (United States)

    Hengge, Regine

    2016-11-01

    The bacterial second messenger c-di-GMP controls bacterial biofilm formation, motility, cell cycle progression, development and virulence. It is synthesized by diguanylate cyclases (with GGDEF domains), degraded by specific phosphodiesterases (PDEs, with EAL of HD-GYP domains) and sensed by a wide variety of c-di-GMP-binding effectors that control diverse targets. c-di-GMP-binding effectors can be riboswitches as well as proteins with highly diverse structures and functions. The latter include 'degenerate' GGDEF/EAL domain proteins that are enzymatically inactive but still able to bind c-di-GMP. Surprisingly, two enzymatically active 'trigger PDEs', the Escherichia coli proteins PdeR and PdeL, have recently been added to this list of c-di-GMP-sensing effectors. Mechanistically, trigger PDEs are multifunctional. They directly and specifically interact with a macromolecular target (e.g. with a transcription factor or directly with a promoter region), whose activity they control by their binding and degradation of c-di-GMP-their PDE activity thus represents the c-di-GMP sensor or effector function. In this process, c-di-GMP serves as a regulatory ligand, but in contrast to classical allosteric control, this ligand is also degraded. The resulting kinetics and circuitry of control are ideally suited for trigger PDEs to serve as key components in regulatory switches.This article is part of the themed issue 'The new bacteriology'.

  13. c-di-GMP induction of Dictyostelium cell death requires the polyketide DIF-1.

    Science.gov (United States)

    Song, Yu; Luciani, Marie-Françoise; Giusti, Corinne; Golstein, Pierre

    2015-02-15

    Cell death in the model organism Dictyostelium, as studied in monolayers in vitro, can be induced by the polyketide DIF-1 or by the cyclical dinucleotide c-di-GMP. c-di-GMP, a universal bacterial second messenger, can trigger innate immunity in bacterially infected animal cells and is involved in developmental cell death in Dictyostelium. We show here that c-di-GMP was not sufficient to induce cell death in Dictyostelium cell monolayers. Unexpectedly, it also required the DIF-1 polyketide. The latter could be exogenous, as revealed by a telling synergy between c-di-GMP and DIF-1. The required DIF-1 polyketide could also be endogenous, as shown by the inability of c-di-GMP to induce cell death in Dictyostelium HMX44A cells and DH1 cells upon pharmacological or genetic inhibition of DIF-1 biosynthesis. In these cases, c-di-GMP-induced cell death was rescued by complementation with exogenous DIF-1. Taken together, these results demonstrated that c-di-GMP could trigger cell death in Dictyostelium only in the presence of the DIF-1 polyketide or its metabolites. This identified another element of control to this cell death and perhaps also to c-di-GMP effects in other situations and organisms.

  14. Near-infrared light responsive synthetic c-di-GMP module for optogenetic applications.

    Science.gov (United States)

    Ryu, Min-Hyung; Gomelsky, Mark

    2014-11-21

    Enormous potential of cell-based therapeutics is hindered by the lack of effective means to control genetically engineered cells in mammalian tissues. Here, we describe a synthetic module for remote photocontrol of engineered cells that can be adapted for such applications. The module involves photoactivated synthesis of cyclic dimeric GMP (c-di-GMP), a stable small molecule that is not produced by higher eukaryotes and therefore is suitable for orthogonal regulation. The key component of the photocontrol module is an engineered bacteriophytochrome diguanylate cyclase, which synthesizes c-di-GMP from GTP in a light-dependent manner. Bacteriophytochromes are particularly attractive photoreceptors because they respond to light in the near-infrared window of the spectrum, where absorption by mammalian tissues is minimal, and also because their chromophore, biliverdin IXα, is naturally available in mammalian cells. The second component of the photocontrol module, a c-di-GMP phosphodiesterase, maintains near-zero background levels of c-di-GMP in the absence of light, which enhances the photodynamic range of c-di-GMP concentrations. In the E. coli model used in this study, the intracellular c-di-GMP levels could be upregulated by light by >50-fold. Various c-di-GMP-responsive proteins and riboswitches identified in bacteria can be linked downstream of the c-di-GMP-mediated photocontrol module for orthogonal regulation of biological activities in mammals as well as in other organisms lacking c-di-GMP signaling. Here, we linked the photocontrol module to a gene expression output via a c-di-GMP-responsive transcription factor and achieved a 40-fold photoactivation of gene expression.

  15. The anti-cancerous drug doxorubicin decreases the c-di-GMP content in Pseudomonas aeruginosa but promotes biofilm formation

    DEFF Research Database (Denmark)

    Groizeleau, Julie; Rybtke, Morten; Andersen, Jens Bo

    2016-01-01

    for their potential c-di-GMP-lowering effect using a recently developed c-di-GMP biosensor strain. Our screen identified the anti-cancerous drug doxorubicin as a potent c-di-GMP inhibitor. In addition, the drug decreased the transcription of many biofilm-related genes. However, despite its effect on the c...

  16. Trigger phosphodiesterases as a novel class of c-di-GMP effector proteins

    Science.gov (United States)

    2016-01-01

    The bacterial second messenger c-di-GMP controls bacterial biofilm formation, motility, cell cycle progression, development and virulence. It is synthesized by diguanylate cyclases (with GGDEF domains), degraded by specific phosphodiesterases (PDEs, with EAL of HD-GYP domains) and sensed by a wide variety of c-di-GMP-binding effectors that control diverse targets. c-di-GMP-binding effectors can be riboswitches as well as proteins with highly diverse structures and functions. The latter include ‘degenerate’ GGDEF/EAL domain proteins that are enzymatically inactive but still able to bind c-di-GMP. Surprisingly, two enzymatically active ‘trigger PDEs’, the Escherichia coli proteins PdeR and PdeL, have recently been added to this list of c-di-GMP-sensing effectors. Mechanistically, trigger PDEs are multifunctional. They directly and specifically interact with a macromolecular target (e.g. with a transcription factor or directly with a promoter region), whose activity they control by their binding and degradation of c-di-GMP—their PDE activity thus represents the c-di-GMP sensor or effector function. In this process, c-di-GMP serves as a regulatory ligand, but in contrast to classical allosteric control, this ligand is also degraded. The resulting kinetics and circuitry of control are ideally suited for trigger PDEs to serve as key components in regulatory switches. This article is part of the themed issue ‘The new bacteriology’. PMID:27672149

  17. Host Immune Response to Bacterial Cyclic Diguanylic Acid (c-di-GMP)

    Science.gov (United States)

    2009-07-01

    Materials and Methods c-di-GMP and chemicals used The c-di-GMP (Fig. 1) used in these studies was synthesized and prepared as previously described (19–24...godeoxynucleotide (ODN) 2216 (25). LPS endotoxin (Limulus amebocyte lysate assay) test A dose of 500 M c-di-GMP was tested for the presence of LPS endotoxin using...inoculation, 100 CFU of S. aureus New- bould 305 (ATCC 29740) were injected into each gland and the coloniza- tion was allowed for 10 h. Raw bacterial CFU

  18. GIL, a new c-di-GMP binding protein domain involved in regulation of cellulose synthesis in enterobacteria

    OpenAIRE

    Fang, Xin; Ahmad, Irfan; Blanka, Andrea; Schottkowski, Marco; Cimdins, Annika; Galperin, Michael Y.; Römling, Ute; Gomelsky, Mark

    2014-01-01

    In contrast to numerous enzymes involved in c-di-GMP synthesis and degradation in enterobacteria, only a handful of c-di-GMP receptors/effectors have been identified. In search of new c-di-GMP receptors, we screened the Escherichia coli ASKA overexpression gene library using the Differential Radial Capillary Action of Ligand Assay (DRaCALA) with fluorescently and radioisotope-labeled c-di-GMP. We uncovered three new candidate c-di-GMP receptors in E. coli and characterized one of them, BcsE. ...

  19. The expanding roles of c-di-GMP in the biosynthesis of exopolysaccharides and secondary metabolites.

    Science.gov (United States)

    Liang, Zhao-Xun

    2015-05-01

    The cyclic dinucleotide c-di-GMP has emerged in the last decade as a prevalent intracellular messenger that orchestrates the transition between the motile and sessile lifestyles of many bacterial species. The motile-to-sessile transition is often associated with the formation of extracellular matrix-encased biofilm, an organized community of bacterial cells that often contributes to antibiotic resistance and host-pathogen interaction. It is increasingly clear that c-di-GMP controls motility, biofilm formation and bacterial pathogenicity partially through regulating the production of exopolysaccharides (EPS) and small-molecule secondary metabolites. This review summarizes our current understanding of the regulation of EPS biosynthesis by c-di-GMP in a diversity of bacterial species and highlights the emerging role of c-di-GMP in the biosynthesis of small-molecule secondary metabolites.

  20. Structural basis for c-di-GMP-mediated inside-out signaling controlling periplasmic proteolysis.

    Directory of Open Access Journals (Sweden)

    Marcos V A S Navarro

    Full Text Available The bacterial second messenger bis-(3'-5' cyclic dimeric guanosine monophosphate (c-di-GMP has emerged as a central regulator for biofilm formation. Increased cellular c-di-GMP levels lead to stable cell attachment, which in Pseudomonas fluorescens requires the transmembrane receptor LapD. LapD exhibits a conserved and widely used modular architecture containing a HAMP domain and degenerate diguanylate cyclase and phosphodiesterase domains. c-di-GMP binding to the LapD degenerate phosphodiesterase domain is communicated via the HAMP relay to the periplasmic domain, triggering sequestration of the protease LapG, thus preventing cleavage of the surface adhesin LapA. Here, we elucidate the molecular mechanism of autoinhibition and activation of LapD based on structure-function analyses and crystal structures of the entire periplasmic domain and the intracellular signaling unit in two different states. In the absence of c-di-GMP, the intracellular module assumes an inactive conformation. Binding of c-di-GMP to the phosphodiesterase domain disrupts the inactive state, permitting the formation of a trans-subunit dimer interface between adjacent phosphodiesterase domains via interactions conserved in c-di-GMP-degrading enzymes. Efficient mechanical coupling of the conformational changes across the membrane is realized through an extensively domain-swapped, unique periplasmic fold. Our structural and functional analyses identified a conserved system for the regulation of periplasmic proteases in a wide variety of bacteria, including many free-living and pathogenic species.

  1. New insights into Legionella pneumophila biofilm regulation by c-di-GMP signaling.

    Science.gov (United States)

    Pécastaings, Sophie; Allombert, Julie; Lajoie, Barbora; Doublet, Patricia; Roques, Christine; Vianney, Anne

    2016-09-01

    The waterborne pathogen Legionella pneumophila grows as a biofilm, freely or inside amoebae. Cyclic-di-GMP (c-di-GMP), a bacterial second messenger frequently implicated in biofilm formation, is synthesized and degraded by diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), respectively. To characterize the c-di-GMP-metabolizing enzymes involved in L. pneumophila biofilm regulation, the consequences on biofilm formation and the c-di-GMP concentration of each corresponding gene inactivation were assessed in the Lens strain. The results showed that one DGC and two PDEs enhance different aspects of biofilm formation, while two proteins with dual activity (DGC/PDE) inhibit biofilm growth. Surprisingly, only two mutants exhibited a change in global c-di-GMP concentration. This study highlights that specific c-di-GMP pathways control L. pneumophila biofilm formation, most likely via temporary and/or local modulation of c-di-GMP concentration. Furthermore, Lpl1054 DGC is required to enable the formation a dense biofilm in response to nitric oxide, a signal for biofilm dispersion in many other species.

  2. Structural and Biochemical Determinants of Ligand Binding by the c-di-GMP Riboswitch

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.; Lipchock, S; Livingston,; Shanahan, C; Strobel, S

    2010-01-01

    The bacterial second messenger c-di-GMP is used in many species to control essential processes that allow the organism to adapt to its environment. The c-di-GMP riboswitch (GEMM) is an important downstream target in this signaling pathway and alters gene expression in response to changing concentrations of c-di-GMP. The riboswitch selectively recognizes its second messenger ligand primarily through contacts with two critical nucleotides. However, these two nucleotides are not the most highly conserved residues within the riboswitch sequence. Instead, nucleotides that stack with c-di-GMP and that form tertiary RNA contacts are the most invariant. Biochemical and structural evidence reveals that the most common natural variants are able to make alternative pairing interactions with both guanine bases of the ligand. Additionally, a high-resolution (2.3 {angstrom}) crystal structure of the native complex reveals that a single metal coordinates the c-di-GMP backbone. Evidence is also provided that after transcription of the first nucleotide on the 3{prime}-side of the P1 helix, which is predicted to be the molecular switch, the aptamer is functional for ligand binding. Although large energetic effects occur when several residues in the RNA are altered, mutations at the most conserved positions, rather than at positions that base pair with c-di-GMP, have the most detrimental effects on binding. Many mutants retain sufficient c-di-GMP affinity for the RNA to remain biologically relevant, which suggests that this motif is quite resilient to mutation.

  3. The c-di-GMP phosphodiesterase BifA regulates biofilm development in Pseudomonas putida.

    Science.gov (United States)

    Jiménez-Fernández, Alicia; López-Sánchez, Aroa; Calero, Patricia; Govantes, Fernando

    2015-02-01

    We previously showed the isolation of biofilmpersistent Pseudomonas putida mutants that fail to undergo biofilm dispersal upon entry in stationary phase. Two such mutants were found to bear insertions in PP0914, encoding a GGDEF/EAL domain protein with high similarity to Pseudomon asaeruginosa BifA. Here we show the phenotypic characterization of a ΔbifA mutant in P. putida KT2442.This mutant displayed increased biofilm and pellicle formation, cell aggregation in liquid medium and decreased starvation-induced biofilm dispersal relative to the wild type. Unlike its P. aeruginosa counterpart, P. putida BifA did not affect swarming motility. The hyperadherent phenotype of the ΔbifA mutant correlates with a general increase in cyclic diguanylate (c-di-GMP) levels, Congo Red-binding exopolyaccharide production and transcription of the adhesin-encoding lapA gene. Integrity of the EAL motif and a modified GGDEF motif (altered to GGDQF)were crucial for BifA activity, and c-di-GMP depletion by overexpression of a heterologous c-di-GMP phosphodiesterase in the ΔbifA mutant restored wild-type biofilm dispersal and lapA expression.Our results indicate that BifA is a phosphodiesterase involved in the regulation of the c-di-GMP pool and required for the generation of the low c-di-GMP signal that triggers starvation-induced biofilm dispersal.

  4. Bacterial c-di-GMP affects hematopoietic stem/progenitors and their niches through STING.

    Science.gov (United States)

    Kobayashi, Hiroshi; Kobayashi, Chiharu I; Nakamura-Ishizu, Ayako; Karigane, Daiki; Haeno, Hiroshi; Yamamoto, Kimiyo N; Sato, Taku; Ohteki, Toshiaki; Hayakawa, Yoshihiro; Barber, Glen N; Kurokawa, Mineo; Suda, Toshio; Takubo, Keiyo

    2015-04-01

    Upon systemic bacterial infection, hematopoietic stem and progenitor cells (HSPCs) migrate to the periphery in order to supply a sufficient number of immune cells. Although pathogen-associated molecular patterns reportedly mediate HSPC activation, how HSPCs detect pathogen invasion in vivo remains elusive. Bacteria use the second messenger bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) for a variety of activities. Here, we report that c-di-GMP comprehensively regulated both HSPCs and their niche cells through an innate immune sensor, STING, thereby inducing entry into the cell cycle and mobilization of HSPCs while decreasing the number and repopulation capacity of long-term hematopoietic stem cells. Furthermore, we show that type I interferon acted as a downstream target of c-di-GMP to inhibit HSPC expansion in the spleen, while transforming growth factor-β was required for c-di-GMP-dependent splenic HSPC expansion. Our results define machinery underlying the dynamic regulation of HSPCs and their niches during bacterial infection through c-di-GMP/STING signaling.

  5. c-di-GMP enhances protective innate immunity in a murine model of pertussis.

    Directory of Open Access Journals (Sweden)

    Shokrollah Elahi

    Full Text Available Innate immunity represents the first line of defense against invading pathogens in the respiratory tract. Innate immune cells such as monocytes, macrophages, dendritic cells, NK cells, and granulocytes contain specific pathogen-recognition molecules which induce the production of cytokines and subsequently activate the adaptive immune response. c-di-GMP is a ubiquitous second messenger that stimulates innate immunity and regulates biofilm formation, motility and virulence in a diverse range of bacterial species with potent immunomodulatory properties. In the present study, c-di-GMP was used to enhance the innate immune response against pertussis, a respiratory infection mainly caused by Bordetella pertussis. Intranasal treatment with c-di-GMP resulted in the induction of robust innate immune responses to infection with B. pertussis characterized by enhanced recruitment of neutrophils, macrophages, natural killer cells and dendritic cells. The immune responses were associated with an earlier and more vigorous expression of Th1-type cytokines, as well as an increase in the induction of nitric oxide in the lungs of treated animals, resulting in significant reduction of bacterial numbers in the lungs of infected mice. These results demonstrate that c-di-GMP is a potent innate immune stimulatory molecule that can be used to enhance protection against bacterial respiratory infections. In addition, our data suggest that priming of the innate immune system by c-di-GMP could further skew the immune response towards a Th1 type phenotype during subsequent infection. Thus, our data suggest that c-di-GMP might be useful as an adjuvant for the next generation of acellular pertussis vaccine to mount a more protective Th1 phenotype immune response, and also in other systems where a Th1 type immune response is required.

  6. GIL, a new c-di-GMP-binding protein domain involved in regulation of cellulose synthesis in enterobacteria.

    Science.gov (United States)

    Fang, Xin; Ahmad, Irfan; Blanka, Andrea; Schottkowski, Marco; Cimdins, Annika; Galperin, Michael Y; Römling, Ute; Gomelsky, Mark

    2014-08-01

    In contrast to numerous enzymes involved in c-di-GMP synthesis and degradation in enterobacteria, only a handful of c-di-GMP receptors/effectors have been identified. In search of new c-di-GMP receptors, we screened the Escherichia coli ASKA overexpression gene library using the Differential Radial Capillary Action of Ligand Assay (DRaCALA) with fluorescently and radioisotope-labelled c-di-GMP. We uncovered three new candidate c-di-GMP receptors in E. coli and characterized one of them, BcsE. The bcsE gene is encoded in cellulose synthase operons in representatives of Gammaproteobacteria and Betaproteobacteria. The purified BcsE proteins from E. coli, Salmonella enterica and Klebsiella pneumoniae bind c-di-GMP via the domain of unknown function, DUF2819, which is hereby designated GIL, GGDEF I-site like domain. The RxGD motif of the GIL domain is required for c-di-GMP binding, similar to the c-di-GMP-binding I-site of the diguanylate cyclase GGDEF domain. Thus, GIL is the second protein domain, after PilZ, dedicated to c-di-GMP-binding. We show that in S. enterica, BcsE is not essential for cellulose synthesis but is required for maximal cellulose production, and that c-di-GMP binding is critical for BcsE function. It appears that cellulose production in enterobacteria is controlled by a two-tiered c-di-GMP-dependent system involving BcsE and the PilZ domain containing glycosyltransferase BcsA.

  7. Dimeric c-di-GMP is required for post-translational regulation of alginate production in Pseudomonas aeruginosa.

    Science.gov (United States)

    Whitney, John C; Whitfield, Gregory B; Marmont, Lindsey S; Yip, Patrick; Neculai, A Mirela; Lobsanov, Yuri D; Robinson, Howard; Ohman, Dennis E; Howell, P Lynne

    2015-05-15

    Pseudomonas aeruginosa is an opportunistic human pathogen that secretes the exopolysaccharide alginate during infection of the respiratory tract of individuals afflicted with cystic fibrosis and chronic obstructive pulmonary disease. Among the proteins required for alginate production, Alg44 has been identified as an inner membrane protein whose bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) binding activity post-translationally regulates alginate secretion. In this study, we report the 1.8 Å crystal structure of the cytoplasmic region of Alg44 in complex with dimeric self-intercalated c-di-GMP and characterize its dinucleotide-binding site using mutational analysis. The structure shows that the c-di-GMP binding region of Alg44 adopts a PilZ domain fold with a dimerization mode not previously observed for this family of proteins. Calorimetric binding analysis of residues in the c-di-GMP binding site demonstrate that mutation of Arg-17 and Arg-95 alters the binding stoichiometry between c-di-GMP and Alg44 from 2:1 to 1:1. Introduction of these mutant alleles on the P. aeruginosa chromosome show that the residues required for binding of dimeric c-di-GMP in vitro are also required for efficient alginate production in vivo. These results suggest that the dimeric form of c-di-GMP represents the biologically active signaling molecule needed for the secretion of an important virulence factor produced by P. aeruginosa.

  8. Bi-modal distribution of the second messenger c-di-GMP controls cell fate and asymmetry during the caulobacter cell cycle.

    Directory of Open Access Journals (Sweden)

    Sören Abel

    Full Text Available Many bacteria mediate important life-style decisions by varying levels of the second messenger c-di-GMP. Behavioral transitions result from the coordination of complex cellular processes such as motility, surface adherence or the production of virulence factors and toxins. While the regulatory mechanisms responsible for these processes have been elucidated in some cases, the global pleiotropic effects of c-di-GMP are poorly understood, primarily because c-di-GMP networks are inherently complex in most bacteria. Moreover, the quantitative relationships between cellular c-di-GMP levels and c-di-GMP dependent phenotypes are largely unknown. Here, we dissect the c-di-GMP network of Caulobacter crescentus to establish a global and quantitative view of c-di-GMP dependent processes in this organism. A genetic approach that gradually reduced the number of diguanylate cyclases identified novel c-di-GMP dependent cellular processes and unraveled c-di-GMP as an essential component of C. crescentus cell polarity and its bimodal life cycle. By varying cellular c-di-GMP concentrations, we determined dose response curves for individual c-di-GMP-dependent processes. Relating these values to c-di-GMP levels modeled for single cells progressing through the cell cycle sets a quantitative frame for the successive activation of c-di-GMP dependent processes during the C. crescentus life cycle. By reconstructing a simplified c-di-GMP network in a strain devoid of c-di-GMP we defined the minimal requirements for the oscillation of c-di-GMP levels during the C. crescentus cell cycle. Finally, we show that although all c-di-GMP dependent cellular processes were qualitatively restored by artificially adjusting c-di-GMP levels with a heterologous diguanylate cyclase, much higher levels of the second messenger are required under these conditions as compared to the contribution of homologous c-di-GMP metabolizing enzymes. These experiments suggest that a common c-di-GMP pool

  9. c-di-GMP signalling and the regulation of developmental transitions in streptomycetes.

    Science.gov (United States)

    Bush, Matthew J; Tschowri, Natalia; Schlimpert, Susan; Flärdh, Klas; Buttner, Mark J

    2015-12-01

    The complex life cycle of streptomycetes involves two distinct filamentous cell forms: the growing (or vegetative) hyphae and the reproductive (or aerial) hyphae, which differentiate into long chains of spores. Until recently, little was known about the signalling pathways that regulate the developmental transitions leading to sporulation. In this Review, we discuss important new insights into these pathways that have led to the emergence of a coherent regulatory network, focusing on the erection of aerial hyphae and the synchronous cell division event that produces dozens of unigenomic spores. In particular, we highlight the role of cyclic di-GMP (c-di-GMP) in controlling the initiation of development, and the role of the master regulator BldD in mediating c-di-GMP signalling.

  10. Complex regulatory network encompassing the Csr, c-di-GMP and motility systems of Salmonella Typhimurium.

    Science.gov (United States)

    Jonas, Kristina; Edwards, Adrianne N; Ahmad, Irfan; Romeo, Tony; Römling, Ute; Melefors, Ojar

    2010-02-01

    Bacterial survival depends on the ability to switch between sessile and motile lifestyles in response to changing environmental conditions. In many species, this switch is governed by (3'-5')-cyclic-diguanosine monophosphate (c-di-GMP), a signalling molecule, which is metabolized by proteins containing GGDEF and/or EAL domains. Salmonella Typhimurium contains 20 such proteins. Here, we show that the RNA-binding protein CsrA regulates the expression of eight genes encoding GGDEF, GGDEF-EAL and EAL domain proteins. CsrA bound directly to the mRNA leaders of five of these genes, suggesting that it may regulate these genes post-transcriptionally. The c-di-GMP-specific phosphodiesterase STM3611, which reciprocally controls flagella function and production of biofilm matrix components, was regulated by CsrA binding to the mRNA, but was also indirectly regulated by CsrA through the FlhDC/FliA flagella cascade and STM1344. STM1344 is an unconventional (c-di-GMP-inactive) EAL domain protein, recently identified as a negative regulator of flagella gene expression. Here, we demonstrate that CsrA directly downregulates expression of STM1344, which in turn regulates STM3611 through fliA and thus reciprocally controls motility and biofilm factors. Altogether, our data reveal that the concerted and complex regulation of several genes encoding GGDEF/EAL domain proteins allows CsrA to control the motility-sessility switch in S. Typhimurium at multiple levels.

  11. Identification, activity and disulfide connectivity of C-di-GMP regulating proteins in Mycobacterium tuberculosis.

    Directory of Open Access Journals (Sweden)

    Kajal Gupta

    Full Text Available C-di-GMP, a bacterial second messenger plays a key role in survival and adaptation of bacteria under different environmental conditions. The level of c-di-GMP is regulated by two opposing activities, namely diguanylate cyclase (DGC and phosphodiesterase (PDE-A exhibited by GGDEF and EAL domain, respectively in the same protein. Previously, we reported a bifunctional GGDEF-EAL domain protein, MSDGC-1 from Mycobacterium smegmatis showing both these activities (Kumar and Chatterji, 2008. In this current report, we have identified and characterized the homologous protein from Mycobacterium tuberculosis (Rv 1354c named as MtbDGC. MtbDGC is also a bifunctional protein, which can synthesize and degrade c-di-GMP in vitro. Further we expressed Mtbdgc in M. smegmatis and it was able to complement the MSDGC-1 knock out strain by restoring the long term survival of M. smegmatis. Another protein Rv 1357c, named as MtbPDE, is an EAL domain protein and degrades c-di-GMP to pGpG in vitro. Rv1354c and 1357c have seven cysteine amino acids in their sequence, distributed along the full length of the protein. Disulfide bonds play an important role in stabilizing protein structure and regulating protein function. By proteolytic digestion and mass spectrometric analysis of MtbDGC, connectivity between cysteine pairs Cys94-Cys584, Cys2-Cys479 and Cys429-Cys614 was determined, whereas the third cysteine (Cys406 from N terminal was found to be free in MtbDGC protein, which was further confirmed by alkylation with iodoacetamide labeling. Bioinformatics modeling investigations also supported the pattern of disulfide connectivity obtained by Mass spectrometric analysis. Cys406 was mutated to serine by site directed mutagenesis and the mutant MtbC406S was not found to be active and was not able to synthesize or degrade c-di-GMP. The disulfide connectivity established here would help further in understanding the structure - function relationship in MtbDGC.

  12. Mechanistic insights into c-di-GMP-dependent control of the biofilm regulator FleQ from Pseudomonas aeruginosa.

    Science.gov (United States)

    Matsuyama, Bruno Y; Krasteva, Petya V; Baraquet, Claudine; Harwood, Caroline S; Sondermann, Holger; Navarro, Marcos V A S

    2016-01-12

    Bacterial biofilm formation during chronic infections confers increased fitness, antibiotic tolerance, and cytotoxicity. In many pathogens, the transition from a planktonic lifestyle to collaborative, sessile biofilms represents a regulated process orchestrated by the intracellular second-messenger c-di-GMP. A main effector for c-di-GMP signaling in the opportunistic pathogen Pseudomonas aeruginosa is the transcription regulator FleQ. FleQ is a bacterial enhancer-binding protein (bEBP) with a central AAA+ ATPase σ(54)-interaction domain, flanked by a C-terminal helix-turn-helix DNA-binding motif and a divergent N-terminal receiver domain. Together with a second ATPase, FleN, FleQ regulates the expression of flagellar and exopolysaccharide biosynthesis genes in response to cellular c-di-GMP. Here we report structural and functional data that reveal an unexpected mode of c-di-GMP recognition that is associated with major conformational rearrangements in FleQ. Crystal structures of FleQ's AAA+ ATPase domain in its apo-state or bound to ADP or ATP-γ-S show conformations reminiscent of the activated ring-shaped assemblies of other bEBPs. As revealed by the structure of c-di-GMP-complexed FleQ, the second messenger interacts with the AAA+ ATPase domain at a site distinct from the ATP binding pocket. c-di-GMP interaction leads to active site obstruction, hexameric ring destabilization, and discrete quaternary structure transitions. Solution and cell-based studies confirm coupling of the ATPase active site and c-di-GMP binding, as well as the functional significance of crystallographic interprotomer interfaces. Taken together, our data offer unprecedented insight into conserved regulatory mechanisms of gene expression under direct c-di-GMP control via FleQ and FleQ-like bEBPs.

  13. A direct screen for c-di-GMP modulators reveals a Salmonella Typhimurium periplasmic ʟ-arginine-sensing pathway.

    Science.gov (United States)

    Mills, Erez; Petersen, Erik; Kulasekara, Bridget R; Miller, Samuel I

    2015-06-01

    Cyclic-di-GMP (c-di-GMP) is a bacterial second messenger that transduces internal and external signals and regulates bacterial motility and biofilm formation. Some organisms encode more than 100 c-di-GMP-modulating enzymes, but only for a few has a signal been defined that modulates their activity. We developed and applied a high-throughput, real-time flow cytometry method that uses a fluorescence resonance energy transfer (FRET)-based biosensor of free c-di-GMP to screen for signals that modulate its concentration within Salmonella Typhimurium. We identified multiple compounds, including glucose, N-acetyl-d-glucosamine, salicylic acid, and ʟ-arginine, that modulated the FRET signal and therefore the free c-di-GMP concentration. By screening a library of mutants, we identified proteins required for the c-di-GMP response to each compound. Furthermore, low micromolar concentrations of ʟ-arginine induced a rapid translation-independent increase in c-di-GMP concentrations and c-di-GMP-dependent cellulose synthesis, responses that required the regulatory periplasmic domain of the diguanylate cyclase STM1987. ʟ-Arginine signaling also required the periplasmic putative ʟ-arginine-binding protein ArtI, implying that ʟ-arginine sensing occurred in the periplasm. Among the 20 commonly used amino acids, S. Typhimurium specifically responded to ʟ-arginine with an increase in c-di-GMP, suggesting that ʟ-arginine may serve as a signal during S. Typhimurium infection. Our results demonstrate that a second-messenger biosensor can be used to identify environmental signals and define pathways that alter microbial behavior.

  14. A Minimal Threshold of c-di-GMP Is Essential for Fruiting Body Formation and Sporulation in Myxococcus xanthus.

    Science.gov (United States)

    Skotnicka, Dorota; Smaldone, Gregory T; Petters, Tobias; Trampari, Eleftheria; Liang, Jennifer; Kaever, Volkhard; Malone, Jacob G; Singer, Mitchell; Søgaard-Andersen, Lotte

    2016-05-01

    Generally, the second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) regulates the switch between motile and sessile lifestyles in bacteria. Here, we show that c-di-GMP is an essential regulator of multicellular development in the social bacterium Myxococcus xanthus. In response to starvation, M. xanthus initiates a developmental program that culminates in formation of spore-filled fruiting bodies. We show that c-di-GMP accumulates at elevated levels during development and that this increase is essential for completion of development whereas excess c-di-GMP does not interfere with development. MXAN3735 (renamed DmxB) is identified as a diguanylate cyclase that only functions during development and is responsible for this increased c-di-GMP accumulation. DmxB synthesis is induced in response to starvation, thereby restricting DmxB activity to development. DmxB is essential for development and functions downstream of the Dif chemosensory system to stimulate exopolysaccharide accumulation by inducing transcription of a subset of the genes encoding proteins involved in exopolysaccharide synthesis. The developmental defects in the dmxB mutant are non-cell autonomous and rescued by co-development with a strain proficient in exopolysaccharide synthesis, suggesting reduced exopolysaccharide accumulation as the causative defect in this mutant. The NtrC-like transcriptional regulator EpsI/Nla24, which is required for exopolysaccharide accumulation, is identified as a c-di-GMP receptor, and thus a putative target for DmxB generated c-di-GMP. Because DmxB can be-at least partially-functionally replaced by a heterologous diguanylate cyclase, these results altogether suggest a model in which a minimum threshold level of c-di-GMP is essential for the successful completion of multicellular development in M. xanthus.

  15. Elevated level of the second messenger c-di-GMP in Comamonas testosteroni enhances biofilm formation and biofilm-based biodegradation of 3-chloroaniline.

    Science.gov (United States)

    Wu, Yichao; Ding, Yuanzhao; Cohen, Yehuda; Cao, Bin

    2015-02-01

    The bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous second messenger that determines bacterial lifestyle between the planktonic and biofilm modes of life. Although the role of c-di-GMP signaling in biofilm development and dispersal has been extensively studied, how c-di-GMP signaling influences environmental bioprocess activities such as biodegradation remains unexplored. To elucidate the impacts of elevating c-di-GMP level on environmental bioprocesses, we constructed a Comamonas testosteroni strain constitutively expressing a c-di-GMP synthase YedQ from Escherichia coli and examined its capability in biofilm formation and biodegradation of 3-chloroaniline (3-CA). The high c-di-GMP strain exhibited an increased binding to Congo red dye, a decreased motility, and an enhanced biofilm formation capability. In planktonic cultures, the strain with an elevated c-di-GMP concentration and the wild type could degrade 3-CA comparably well. However, under batch growth conditions with a high surface to volume ratio, an elevated c-di-GMP concentration in C. testosteroni significantly increased the contribution of biofilms in 3-CA biodegradation. In continuous submerged biofilm reactors, C. testosteroni with an elevated c-di-GMP level exhibited an enhanced 3-CA biodegradation and a decreased cell detachment rate. Taken together, this study provides a novel strategy to enhance biofilm-based biodegradation of toxic xenobiotic compounds through manipulating bacterial c-di-GMP signaling.

  16. The CRP/FNR family protein Bcam1349 is a c-di-GMP effector that regulates biofilm formation in the respiratory pathogen Burkholderia cenocepacia

    DEFF Research Database (Denmark)

    Fazli, Mustafa; O'Connell, Aileen; Nilsson, Martin

    2011-01-01

    to control a wide range of functions in bacteria, but little is known about these regulatory mechanisms in B. cenocepacia. Here we investigated the role that c-di-GMP plays in the regulation of biofilm formation and virulence in B. cenocepacia. Elevated intracellular levels of c-di-GMP promoted wrinkly...... colony, pellicle and biofilm formation in B. cenocepacia. A screen for transposon mutants unable to respond to elevated levels of c-di-GMP led to the identification of the mutant bcam1349 that did not display increased biofilm and pellicle formation with excessive c-di-GMP levels, and displayed a biofilm...... larvae infection model. Taken together, these findings suggest that the Bcam1349 protein is a transcriptional regulator that binds c-di-GMP and regulates biofilm formation and virulence in B. cenocepacia in response to the level of c-di-GMP....

  17. Differential Regulation of c-di-GMP Metabolic Enzymes by Environmental Signals Modulates Biofilm Formation in Yersinia pestis

    Science.gov (United States)

    Ren, Gai-Xian; Fan, Sai; Guo, Xiao-Peng; Chen, Shiyun; Sun, Yi-Cheng

    2016-01-01

    Cyclic diguanylate (c-di-GMP) is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs), HmsT and HmsD and one phosphodiesterase (PDE), HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD, and HmsP in Y. pestis. Biofilm formation was higher in the presence of non-lethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulate activity of DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments. PMID:27375563

  18. Capture compound mass spectrometry--a powerful tool to identify novel c-di-GMP effector proteins.

    Science.gov (United States)

    Laventie, Benoît-Joseph; Nesper, Jutta; Ahrné, Erik; Glatter, Timo; Schmidt, Alexander; Jenal, Urs

    2015-01-01

    Considerable progress has been made during the last decade towards the identification and characterization of enzymes involved in the synthesis (diguanylate cyclases) and degradation (phosphodiesterases) of the second messenger c-di-GMP. In contrast, little information is available regarding the molecular mechanisms and cellular components through which this signaling molecule regulates a diverse range of cellular processes. Most of the known effector proteins belong to the PilZ family or are degenerated diguanylate cyclases or phosphodiesterases that have given up on catalysis and have adopted effector function. Thus, to better define the cellular c-di-GMP network in a wide range of bacteria experimental methods are required to identify and validate novel effectors for which reliable in silico predictions fail. We have recently developed a novel Capture Compound Mass Spectrometry (CCMS) based technology as a powerful tool to biochemically identify and characterize c-di-GMP binding proteins. This technique has previously been reported to be applicable to a wide range of organisms(1). Here we give a detailed description of the protocol that we utilize to probe such signaling components. As an example, we use Pseudomonas aeruginosa, an opportunistic pathogen in which c-di-GMP plays a critical role in virulence and biofilm control. CCMS identified 74% (38/51) of the known or predicted components of the c-di-GMP network. This study explains the CCMS procedure in detail, and establishes it as a powerful and versatile tool to identify novel components involved in small molecule signaling.

  19. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth

    DEFF Research Database (Denmark)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten Levin;

    2015-01-01

    tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further...... increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed...... to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth....

  20. Differential Regulation of c-di-GMP Metabolic Enzymes by Environmental Signals Modulates Biofilm Formation in Yersinia pestis.

    Science.gov (United States)

    Ren, Gai-Xian; Fan, Sai; Guo, Xiao-Peng; Chen, Shiyun; Sun, Yi-Cheng

    2016-01-01

    Cyclic diguanylate (c-di-GMP) is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs), HmsT and HmsD and one phosphodiesterase (PDE), HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD, and HmsP in Y. pestis. Biofilm formation was higher in the presence of non-lethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulate activity of DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.

  1. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth.

    Science.gov (United States)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten; Yuan, Mingjun; Andersen, Jens Bo; Nielsen, Thomas E; Givskov, Michael; Tolker-Nielsen, Tim; Cao, Bin; Kjelleberg, Staffan; Yang, Liang

    2015-01-01

    Stress response plays an important role on microbial adaptation under hostile environmental conditions. It is generally unclear how the signaling transduction pathway mediates a stress response in planktonic and biofilm modes of microbial communities simultaneously. Here, we showed that metalloid tellurite (TeO3(2-)) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO3(2-) further increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth.

  2. Differential regulation of c-di-GMP metabolic enzymes by environmental signals modulates biofilm formation in Yersinia pestis

    Directory of Open Access Journals (Sweden)

    Gai-Xian eRen

    2016-06-01

    Full Text Available Cyclic diguanylate (c-di-GMP is essential for Yersinia pestis biofilm formation, which is important for flea-borne blockage-dependent plague transmission. Two diguanylate cyclases (DGCs, HmsT and HmsD and one phosphodiesterase (PDE, HmsP are responsible for the synthesis and degradation of c-di-GMP in Y. pestis. Here, we systematically analyzed the effect of various environmental signals on regulation of the biofilm phenotype, the c-di-GMP levels, and expression of HmsT, HmsD and HmsP in Y. pestis. Biofilm formation was higher in the presence of nonlethal high concentration of CaCl2, MgCl2, CuSO4, sucrose, sodium dodecyl sulfonate, or dithiothreitol, and was lower in the presence of FeCl2 or NaCl. In addition, we found that HmsD plays a major role in biofilm formation in acidic or redox environments. These environmental signals differentially regulated expression of HmsT, HmsP and HmsD, resulting in changes in the intracellular levels of c-di-GMP in Y. pestis. Our results suggest that bacteria can sense various environmental signals, and differentially regulates their DGCs and PDEs to coordinately regulate and adapt metabolism of c-di-GMP and biofilm formation to changing environments.

  3. Biofilms and Cyclic di-GMP (c-di-GMP) Signaling: Lessons from Pseudomonas aeruginosa and Other Bacteria.

    Science.gov (United States)

    Valentini, Martina; Filloux, Alain

    2016-06-10

    The cyclic di-GMP (c-di-GMP) second messenger represents a signaling system that regulates many bacterial behaviors and is of key importance for driving the lifestyle switch between motile loner cells and biofilm formers. This review provides an up-to-date compendium of c-di-GMP pathways connected to biofilm formation, biofilm-associated motilities, and other functionalities in the ubiquitous and opportunistic human pathogen Pseudomonas aeruginosa This bacterium is frequently adopted as a model organism to study bacterial biofilm formation. Importantly, its versatility and adaptation capabilities are linked with a broad range of complex regulatory networks, including a large set of genes involved in c-di-GMP biosynthesis, degradation, and transmission.

  4. Genetic Modulation of c-di-GMP Turnover Affects Multiple Virulence Traits and Bacterial Virulence in Rice Pathogen Dickeya zeae

    Science.gov (United States)

    Chen, Yufan; Lv, Mingfa; Liao, Lisheng; Gu, Yanfang; Liang, Zhibin; Shi, Zurong; Liu, Shiyin; Zhou, Jianuan; Zhang, Lianhui

    2016-01-01

    The frequent outbreaks of rice foot rot disease caused by Dickeya zeae have become a significant concern in rice planting regions and countries, but the regulatory mechanisms that govern the virulence of this important pathogen remain vague. Given that the second messenger cyclic di-GMP (c-di-GMP) is associated with modulation of various virulence-related traits in various microorganisms, here we set to investigate the role of the genes encoding c-di-GMP metabolism in the regulation of the bacterial physiology and virulence by construction all in-frame deletion mutants targeting the annotated c-di-GMP turnover genes in D. zeae strain EC1. Phenotype analyses identified individual mutants showing altered production of exoenzymes and phytotoxins, biofilm formation and bacterial motilities. The results provide useful clues and a valuable toolkit for further characterization and dissection of the regulatory complex that modulates the pathogenesis and persistence of this important bacterial pathogen. PMID:27855163

  5. A c-di-GMP effector system controls cell adhesion by inside-out signaling and surface protein cleavage.

    Directory of Open Access Journals (Sweden)

    Peter D Newell

    Full Text Available In Pseudomonas fluorescens Pf0-1 the availability of inorganic phosphate (Pi is an environmental signal that controls biofilm formation through a cyclic dimeric GMP (c-di-GMP signaling pathway. In low Pi conditions, a c-di-GMP phosphodiesterase (PDE RapA is expressed, depleting cellular c-di-GMP and causing the loss of a critical outer-membrane adhesin LapA from the cell surface. This response involves an inner membrane protein LapD, which binds c-di-GMP in the cytoplasm and exerts a periplasmic output promoting LapA maintenance on the cell surface. Here we report how LapD differentially controls maintenance and release of LapA: c-di-GMP binding to LapD promotes interaction with and inhibition of the periplasmic protease LapG, which targets the N-terminus of LapA. We identify conserved amino acids in LapA required for cleavage by LapG. Mutating these residues in chromosomal lapA inhibits LapG activity in vivo, leading to retention of the adhesin on the cell surface. Mutations with defined effects on LapD's ability to control LapA localization in vivo show concomitant effects on c-di-GMP-dependent LapG inhibition in vitro. To establish the physiological importance of the LapD-LapG effector system, we track cell attachment and LapA protein localization during Pi starvation. Under this condition, the LapA adhesin is released from the surface of cells and biofilms detach from the substratum. This response requires c-di-GMP depletion by RapA, signaling through LapD, and proteolytic cleavage of LapA by LapG. These data, in combination with the companion study by Navarro et al. presenting a structural analysis of LapD's signaling mechanism, give a detailed description of a complete c-di-GMP control circuit--from environmental signal to molecular output. They describe a novel paradigm in bacterial signal transduction: regulation of a periplasmic enzyme by an inner membrane signaling protein that binds a cytoplasmic second messenger.

  6. SiaA/D Interconnects c-di-GMP and RsmA Signaling to Coordinate Cellular Aggregation of Pseudomonas aeruginosa in Response to Environmental Conditions.

    Science.gov (United States)

    Colley, Brendan; Dederer, Verena; Carnell, Michael; Kjelleberg, Staffan; Rice, Scott A; Klebensberger, Janosch

    2016-01-01

    Pseudomonas aeruginosa has emerged as an important opportunistic human pathogen that is often highly resistant to eradication strategies, mediated in part by the formation of multicellular aggregates. Cellular aggregates may occur attached to a surface (biofilm), at the air-liquid interface (pellicle), or as suspended aggregates. Compared to surface attached communities, knowledge about the regulatory processes involved in the formation of suspended cell aggregates is still limited. We have recently described the SiaA/D signal transduction module that regulates macroscopic cell aggregation during growth with, or in the presence of the surfactant SDS. Targets for SiaA/D mediated regulation include the Psl polysaccharide, the CdrAB two-partner secretion system and the CupA fimbriae. While the global regulators c-di-GMP and RsmA are known to inversely coordinate cell aggregation and regulate the expression of several adhesins, their potential impact on the expression of the cupA operon remains unknown. Here, we investigated the function of SiaA (a putative ser/thr phosphatase) and SiaD (a di-guanylate cyclase) in cupA1 expression using transcriptional reporter fusions and qRT-PCR. These studies revealed a novel interaction between the RsmA posttranscriptional regulatory system and SiaA/D mediated macroscopic aggregation. The RsmA/rsmY/Z system was found to affect macroscopic aggregate formation in the presence of surfactant by impacting the stability of the cupA1 mRNA transcript and we reveal that RsmA directly binds to the cupA1 leader sequence in vitro. We further identified that transcription of the RsmA antagonist rsmZ is controlled in a SiaA/D dependent manner during growth with SDS. Finally, we found that the siaD transcript is also under regulatory control of RsmA and that overproduction of RsmA or the deletion of siaD results in decreased cellular cyclic di-guanosine monophosphate (c-di-GMP) levels quantified by a transcriptional reporter, demonstrating that

  7. Novel mixed-linkage β-glucan activated by c-di-GMP in Sinorhizobium meliloti.

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Rodríguez-Carvajal, Miguel Ángel; Romero-Jiménez, Lorena; Farias, Gabriela de Araujo; Lloret, Javier; Gallegos, María Trinidad; Sanjuán, Juan

    2015-02-17

    An artificial increase of cyclic diguanylate (c-di-GMP) levels in Sinorhizobium meliloti 8530, a bacterium that does not carry known cellulose synthesis genes, leads to overproduction of a substance that binds the dyes Congo red and calcofluor. Sugar composition and methylation analyses and NMR studies identified this compound as a linear mixed-linkage (1 → 3)(1 → 4)-β-D-glucan (ML β-glucan), not previously described in bacteria but resembling ML β-glucans found in plants and lichens. This unique polymer is hydrolyzed by the specific endoglucanase lichenase, but, unlike lichenan and barley glucan, it generates a disaccharidic → 4)-β-D-Glcp-(1 → 3)-β-D-Glcp-(1 → repeating unit. A two-gene operon bgsBA required for production of this ML β-glucan is conserved among several genera within the order Rhizobiales, where bgsA encodes a glycosyl transferase with domain resemblance and phylogenetic relationship to curdlan synthases and to bacterial cellulose synthases. ML β-glucan synthesis is subjected to both transcriptional and posttranslational regulation. bgsBA transcription is dependent on the exopolysaccharide/quorum sensing ExpR/SinI regulatory system, and posttranslational regulation seems to involve allosteric activation of the ML β-glucan synthase BgsA by c-di-GMP binding to its C-terminal domain. To our knowledge, this is the first report on a linear mixed-linkage (1 → 3)(1 → 4)-β-glucan produced by a bacterium. The S. meliloti ML β-glucan participates in bacterial aggregation and biofilm formation and is required for efficient attachment to the roots of a host plant, resembling the biological role of cellulose in other bacteria.

  8. N-Acetylglucosamine-dependent biofilm formation in Pectobacterium atrosepticum is cryptic and activated by elevated c-di-GMP levels.

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Coulthurst, Sarah J; Sanjuán, Juan; Salmond, George P C

    2011-12-01

    The phytopathogenic bacterium Pectobacterium atrosepticum (Pba) strain SCRI1043 does not exhibit appreciable biofilm formation under standard laboratory conditions. Here we show that a biofilm-forming phenotype in this strain could be activated from a cryptic state by increasing intracellular levels of c-di-GMP, through overexpression of a constitutively active diguanylate cyclase (PleD*) from Caulobacter crescentus. Randomly obtained Pba transposon mutants defective in the pga operon, involved in synthesis and translocation of poly-β-1,6-N-acetyl-D-glucosamine (PGA), were all impaired in this biofilm formation. The presence of the PGA-degrading enzyme dispersin B in the growth media prevented biofilm formation by Pba overexpressing PleD*, further supporting the importance of PGA for biofilm formation by Pba. Importantly, a pga mutant exhibited a reduction in root binding to the host plant under conditions of high intracellular c-di-GMP levels. A modest but consistent increase in pga transcript levels was associated with high intracellular levels of c-di-GMP. Our results indicate tight control of PGA-dependent biofilm formation by c-di-GMP in Pba.

  9. Genetic Dissection of the Regulatory Network Associated with High C-di-GMP Levels in Pseudomonas putida KT2440

    Directory of Open Access Journals (Sweden)

    María Isabel Ramos-González

    2016-07-01

    Full Text Available Most bacteria grow in nature forming multicellular structures named biofilms. The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP is a key player in the regulation of the transition from planktonic to sessile lifestyles and this regulation is crucial in the development of biofilms. In Pseudomonas putida KT2440, Rup4959, a multidomain response regulator with diguanylate cyclase activity, when overexpressed causes an increment in the intracellular levels of c-di-GMP that gives rise to a pleiotropic phenotype consisting of increased biofilm formation and crinkly colony morphology. In a broad genomic screen we have isolated mutant derivatives that lose the crinkly morphology, designed as cfc (crinkle free colony. A total of nineteen different genes have been identified as being related with the emergence of the cfc phenotype either because the expression or functionality of Rup4959 is compromised, or due to a lack of transduction of the c-di-GMP signal to downstream elements involved in the acquisition of the phenotype. Discernment between these possibilities was investigated by using a c-di-GMP biosensor and by HPLC-MS quantification of the second messenger. Interestingly five of the identified genes encode proteins with AAA+ ATPase domain. Among the bacterial determinants found in this screen are the global transcriptional regulators GacA, AlgU and FleQ and two enzymes involved in the arginine biosynthesis pathway. We present evidences that this pathway seems to be an important element to both the availability of the free pool of the second messenger c-di-GMP and to its further transduction as a signal for biosynthesis of biopolimers. In addition we have identified an uncharacterized hybrid sensor histidine kinase whose phosphoaceptor conserved histidine residue has been shown in this work to be required for in vivo activation of the orphan response regulator Rup4959, which suggests these two elements constitute a two

  10. Genetic Dissection of the Regulatory Network Associated with High c-di-GMP Levels in Pseudomonas putida KT2440

    Science.gov (United States)

    Ramos-González, María Isabel; Travieso, María L.; Soriano, María I.; Matilla, Miguel A.; Huertas-Rosales, Óscar; Barrientos-Moreno, Laura; Tagua, Víctor G.; Espinosa-Urgel, Manuel

    2016-01-01

    Most bacteria grow in nature forming multicellular structures named biofilms. The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) is a key player in the regulation of the transition from planktonic to sessile lifestyles and this regulation is crucial in the development of biofilms. In Pseudomonas putida KT2440, Rup4959, a multidomain response regulator with diguanylate cyclase activity, when overexpressed causes an increment in the intracellular levels of c-di-GMP that gives rise to a pleiotropic phenotype consisting of increased biofilm formation and crinkly colony morphology. In a broad genomic screen we have isolated mutant derivatives that lose the crinkly morphology, designed as cfc (crinkle free colony). A total of 19 different genes have been identified as being related with the emergence of the cfc phenotype either because the expression or functionality of Rup4959 is compromised, or due to a lack of transduction of the c-di-GMP signal to downstream elements involved in the acquisition of the phenotype. Discernment between these possibilities was investigated by using a c-di-GMP biosensor and by HPLC-MS quantification of the second messenger. Interestingly five of the identified genes encode proteins with AAA+ ATPase domain. Among the bacterial determinants found in this screen are the global transcriptional regulators GacA, AlgU and FleQ and two enzymes involved in the arginine biosynthesis pathway. We present evidences that this pathway seems to be an important element to both the availability of the free pool of the second messenger c-di-GMP and to its further transduction as a signal for biosynthesis of biopolimers. In addition we have identified an uncharacterized hybrid sensor histidine kinase whose phosphoaceptor conserved histidine residue has been shown in this work to be required for in vivo activation of the orphan response regulator Rup4959, which suggests these two elements constitute a two-component phosphorelay system

  11. Genetic Dissection of the Regulatory Network Associated with High c-di-GMP Levels in Pseudomonas putida KT2440.

    Science.gov (United States)

    Ramos-González, María Isabel; Travieso, María L; Soriano, María I; Matilla, Miguel A; Huertas-Rosales, Óscar; Barrientos-Moreno, Laura; Tagua, Víctor G; Espinosa-Urgel, Manuel

    2016-01-01

    Most bacteria grow in nature forming multicellular structures named biofilms. The bacterial second messenger cyclic diguanosine monophosphate (c-di-GMP) is a key player in the regulation of the transition from planktonic to sessile lifestyles and this regulation is crucial in the development of biofilms. In Pseudomonas putida KT2440, Rup4959, a multidomain response regulator with diguanylate cyclase activity, when overexpressed causes an increment in the intracellular levels of c-di-GMP that gives rise to a pleiotropic phenotype consisting of increased biofilm formation and crinkly colony morphology. In a broad genomic screen we have isolated mutant derivatives that lose the crinkly morphology, designed as cfc (crinkle free colony). A total of 19 different genes have been identified as being related with the emergence of the cfc phenotype either because the expression or functionality of Rup4959 is compromised, or due to a lack of transduction of the c-di-GMP signal to downstream elements involved in the acquisition of the phenotype. Discernment between these possibilities was investigated by using a c-di-GMP biosensor and by HPLC-MS quantification of the second messenger. Interestingly five of the identified genes encode proteins with AAA+ ATPase domain. Among the bacterial determinants found in this screen are the global transcriptional regulators GacA, AlgU and FleQ and two enzymes involved in the arginine biosynthesis pathway. We present evidences that this pathway seems to be an important element to both the availability of the free pool of the second messenger c-di-GMP and to its further transduction as a signal for biosynthesis of biopolimers. In addition we have identified an uncharacterized hybrid sensor histidine kinase whose phosphoaceptor conserved histidine residue has been shown in this work to be required for in vivo activation of the orphan response regulator Rup4959, which suggests these two elements constitute a two-component phosphorelay system.

  12. Structures of the activator of K. pneumonia biofilm formation, MrkH, indicates PilZ domains involved in c-di-GMP and DNA binding.

    Science.gov (United States)

    Schumacher, Maria A; Zeng, Wenjie

    2016-09-01

    The pathogenesis of Klebsiella pneumonia is linked to the bacteria's ability to form biofilms. Mannose-resistant Klebsiella-like (Mrk) hemagglutinins are critical for K pneumonia biofilm development, and the expression of the genes encoding these proteins is activated by a 3',5'-cyclic diguanylic acid (c-di-GMP)-regulated transcription factor, MrkH. To gain insight into MrkH function, we performed structural and biochemical analyses. Data revealed MrkH to be a monomer with a two-domain architecture consisting of a PilZ C-domain connected to an N domain that unexpectedly also harbors a PilZ-like fold. Comparison of apo- and c-di-GMP-bound MrkH structures reveals a large 138° interdomain rotation that is induced by binding an intercalated c-di-GMP dimer. c-di-GMP interacts with PilZ C-domain motifs 1 and 2 (RxxxR and D/NxSxxG) and a newly described c-di-GMP-binding motif in the MrkH N domain. Strikingly, these c-di-GMP-binding motifs also stabilize an open state conformation in apo MrkH via contacts from the PilZ motif 1 to residues in the C-domain motif 2 and the c-di-GMP-binding N-domain motif. Use of the same regions in apo structure stabilization and c-di-GMP interaction allows distinction between the states. Indeed, domain reorientation by c-di-GMP complexation with MrkH, which leads to a highly compacted structure, suggests a mechanism by which the protein is activated to bind DNA. To our knowledge, MrkH represents the first instance of specific DNA binding mediated by PilZ domains. The MrkH structures also pave the way for the rational design of inhibitors that target K pneumonia biofilm formation.

  13. Characterization of a natural triple-tandem c-di-GMP riboswitch and application of the riboswitch-based dual-fluorescence reporter

    OpenAIRE

    Hang Zhou; Cao Zheng; Jianmei Su; Bo Chen; Yang Fu; Yuqun Xie; Qing Tang; Shan-Ho Chou; Jin He

    2016-01-01

    c-di-GMP riboswitches are structured RNAs located in the 5′-untranslated regions (5′-UTRs) of mRNAs that regulate expression of downstream genes in response to changing concentrations of the second messenger c-di-GMP. We discovered three complete c-di-GMP riboswitches (Bc3, Bc4 and Bc5 RNA) with similar structures, which are arranged in tandem to constitute a triple-tandem (Bc3-5 RNA) riboswitch in the 5′-UTR of the cspABCDE mRNA in Bacillus thuringiensis subsp. chinensis CT-43. Our results s...

  14. A label-free and self-assembled electrochemical biosensor for highly sensitive detection of cyclic diguanylate monophosphate (c-di-GMP) based on RNA riboswitch.

    Science.gov (United States)

    Xie, Qingyun; Zhao, Fulin; Liu, Hongrui; Shan, Yanke; Liu, Fei

    2015-07-02

    Cyclic diguanylate monophosphate (c-di-GMP) is an important second messenger that regulates a variety of complex physiological processes involved in motility, virulence, biofilm formation and cell cycle progression in several bacteria. Herein we report a simple label-free and self-assembled RNA riboswitch-based biosensor for sensitive and selective detection of c-di-GMP. The detectable concentration range of c-di-GMP is from 50 nM to 1 μM with a detection limit of 50 nM.

  15. C-di-GMP regulates Pseudomonas aeruginosa stress response to tellurite during both planktonic and biofilm modes of growth

    DEFF Research Database (Denmark)

    Chua, Song Lin; Sivakumar, Krishnakumar; Rybtke, Morten Levin

    2015-01-01

    increased P. aeruginosa biofilm formation and resistance to TeO3(2-). P. aeruginosa ΔsadCΔsiaD and PAO1/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO3(2-) exposure and had low relative fitness compared to the wild-type PAO1 planktonic and biofilm cultures exposed...... to TeO3(2-). Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth.......Stress response plays an important role on microbial adaptation under hostile environmental conditions. It is generally unclear how the signaling transduction pathway mediates a stress response in planktonic and biofilm modes of microbial communities simultaneously. Here, we showed that metalloid...

  16. Synthesis of Triazole-Linked Analogues of c-di-GMP and Their Interactions with Diguanylate Cyclase.

    Science.gov (United States)

    Fernicola, Silvia; Torquati, Ilaria; Paiardini, Alessandro; Giardina, Giorgio; Rampioni, Giordano; Messina, Marco; Leoni, Livia; Del Bello, Fabio; Petrelli, Riccardo; Rinaldo, Serena; Cappellacci, Loredana; Cutruzzolà, Francesca

    2015-10-22

    Cyclic di-GMP (c-di-GMP) is a widespread second messenger that plays a key role in bacterial biofilm formation. The compound's ability to assume multiple conformations allows it to interact with a diverse set of target macromolecules. Here, we analyzed the binding mode of c-di-GMP to the allosteric inhibitory site (I-site) of diguanylate cyclases (DGCs) and compared it to the conformation adopted in the catalytic site of the EAL phosphodiesterases (PDEs). An array of novel molecules has been designed and synthesized by simplifying the native c-di-GMP structure and replacing the charged phosphodiester backbone with an isosteric nonhydrolyzable 1,2,3-triazole moiety. We developed the first neutral small molecule able to selectively target DGCs discriminating between the I-site of DGCs and the active site of PDEs; this molecule represents a novel tool for mechanistic studies, particularly on those proteins bearing both DGC and PDE modules, and for future optimization studies to target DGCs in vivo.

  17. Selective binding of 2'-F-c-di-GMP to Ct-E88 and Cb-E43, new class I riboswitches from Clostridium tetani and Clostridium botulinum respectively.

    Science.gov (United States)

    Luo, Yiling; Zhou, Jie; Wang, Jingxin; Dayie, T Kwaku; Sintim, Herman O

    2013-06-01

    C-di-GMP is a second messenger in bacteria and partly regulates bacterial physiology by binding to class I and II riboswitches. Four class I c-di-GMP riboswitch aptamer candidates, Ct-E88, Cb-17B, Cb-E43 and Cd-630 RNAs, selected from a GEMM RNA sequence motif in the Rfam database, were expressed and experimentally verified to bind to c-di-GMP. The two newly characterized c-di-GMP riboswitches, Ct-E88 and Cb-E43, bound c-di-GMP with nanomolar Kd whereas the affinities of Cb-17B and Cd-630 for c-di-GMP were at least a 100-fold weaker. Interestingly, whereas the three riboswitches (Vc2, Et-E88 and Cb-E43) bound c-di-GMP with similar Kd values, 2'-modified analogs of c-di-GMP differentially bound to these three class I aptamers. For example, 2'-F-c-di-GMP bound Vc2 with a Kd value of 102 nM whereas the Kd value of 2'-F-c-di-GMP-Ct-E88 is 43 μM (422× higher than that for Vc2 RNA), revealing that there are differences in the binding sites of functional class I c-di-GMP riboswitches.

  18. Formation and dimerization of the phosphodiesterase active site of the Pseudomonas aeruginosa MorA, a bi-functional c-di-GMP regulator.

    Science.gov (United States)

    Phippen, Curtis William; Mikolajek, Halina; Schlaefli, Henry George; Keevil, Charles William; Webb, Jeremy Stephen; Tews, Ivo

    2014-12-20

    Diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively synthesise and hydrolyse the secondary messenger cyclic dimeric GMP (c-di-GMP), and both activities are often found in a single protein. Intracellular c-di-GMP levels in turn regulate bacterial motility, virulence and biofilm formation. We report the first structure of a tandem DGC-PDE fragment, in which the catalytic domains are shown to be active. Two phosphodiesterase states are distinguished by active site formation. The structures, in the presence or absence of c-di-GMP, suggest that dimerisation and binding pocket formation are linked, with dimerisation being required for catalytic activity. An understanding of PDE activation is important, as biofilm dispersal via c-di-GMP hydrolysis has therapeutic effects on chronic infections.

  19. C-di-GMP Regulates Motile to Sessile Transition by Modulating MshA Pili Biogenesis and Near-Surface Motility Behavior in Vibrio cholerae.

    Science.gov (United States)

    Jones, Christopher J; Utada, Andrew; Davis, Kimberly R; Thongsomboon, Wiriya; Zamorano Sanchez, David; Banakar, Vinita; Cegelski, Lynette; Wong, Gerard C L; Yildiz, Fitnat H

    2015-10-01

    In many bacteria, including Vibrio cholerae, cyclic dimeric guanosine monophosphate (c-di-GMP) controls the motile to biofilm life style switch. Yet, little is known about how this occurs. In this study, we report that changes in c-di-GMP concentration impact the biosynthesis of the MshA pili, resulting in altered motility and biofilm phenotypes in V. cholerae. Previously, we reported that cdgJ encodes a c-di-GMP phosphodiesterase and a ΔcdgJ mutant has reduced motility and enhanced biofilm formation. Here we show that loss of the genes required for the mannose-sensitive hemagglutinin (MshA) pilus biogenesis restores motility in the ΔcdgJ mutant. Mutations of the predicted ATPase proteins mshE or pilT, responsible for polymerizing and depolymerizing MshA pili, impair near surface motility behavior and initial surface attachment dynamics. A ΔcdgJ mutant has enhanced surface attachment, while the ΔcdgJmshA mutant phenocopies the high motility and low attachment phenotypes observed in a ΔmshA strain. Elevated concentrations of c-di-GMP enhance surface MshA pilus production. MshE, but not PilT binds c-di-GMP directly, establishing a mechanism for c-di-GMP signaling input in MshA pilus production. Collectively, our results suggest that the dynamic nature of the MshA pilus established by the assembly and disassembly of pilin subunits is essential for transition from the motile to sessile lifestyle and that c-di-GMP affects MshA pilus assembly and function through direct interactions with the MshE ATPase.

  20. Diguanylate cyclase null mutant reveals that C-Di-GMP pathway regulates the motility and adherence of the extremophile bacterium Acidithiobacillus caldus.

    Science.gov (United States)

    Castro, Matías; Deane, Shelly M; Ruiz, Lina; Rawlings, Douglas E; Guiliani, Nicolas

    2015-01-01

    An understanding of biofilm formation is relevant to the design of biological strategies to improve the efficiency of the bioleaching process and to prevent environmental damages caused by acid mine/rock drainage. For this reason, our laboratory is focused on the characterization of the molecular mechanisms involved in biofilm formation in different biomining bacteria. In many bacteria, the intracellular levels of c-di-GMP molecules regulate the transition from the motile planktonic state to sessile community-based behaviors, such as biofilm development, through different kinds of effectors. Thus, we recently started a study of the c-di-GMP pathway in several biomining bacteria including Acidithiobacillus caldus. C-di-GMP molecules are synthesized by diguanylate cyclases (DGCs) and degraded by phosphodiesterases (PDEs). We previously reported the existence of intermediates involved in c-di-GMP pathway from different Acidithiobacillus species. Here, we report our work related to At. caldus ATCC 51756. We identified several putative-ORFs encoding DGC and PDE and effector proteins. By using total RNA extracted from At. caldus cells and RT-PCR, we demonstrated that these genes are expressed. We also demonstrated the presence of c-di-GMP by mass spectrometry and showed that genes for several of the DGC enzymes were functional by heterologous genetic complementation in Salmonella enterica serovar Typhimurium mutants. Moreover, we developed a DGC defective mutant strain (Δc1319) that strongly indicated that the c-di-GMP pathway regulates the swarming motility and adherence to sulfur surfaces by At. caldus. Together, our results revealed that At. caldus possesses a functional c-di-GMP pathway which could be significant for ores colonization during the bioleaching process.

  1. Establishment of a High-throughput Setup for Screening Small Molecules That Modulate c-di-GMP Signaling in Pseudomonas aeruginosa.

    Science.gov (United States)

    Rugjee, Kushal N; An, Shi-Qi; Ryan, Robert P

    2016-06-30

    Bacterial resistance to traditional antibiotics has driven research attempts to identify new drug targets in recently discovered regulatory pathways. Regulatory systems that utilize intracellular cyclic di-GMP (c-di-GMP) as a second messenger are one such class of target. c-di-GMP is a signaling molecule found in almost all bacteria that acts to regulate an extensive range of processes including antibiotic resistance, biofilm formation and virulence. The understanding of how c-di-GMP signaling controls aspects of antibiotic resistant biofilm development has suggested approaches whereby alteration of the cellular concentrations of the nucleotide or disruption of these signaling pathways may lead to reduced biofilm formation or increased susceptibility of the biofilms to antibiotics. We describe a simple high-throughput bioreporter protocol, based on green fluorescent protein (GFP), whose expression is under the control of the c-di-GMP responsive promoter cdrA, to rapidly screen for small molecules with the potential to modulate c-di-GMP cellular levels in Pseudomonas aeruginosa (P. aeruginosa). This simple protocol can screen upwards of 3,500 compounds within 48 hours and has the ability to be adapted to multiple microorganisms.

  2. Homologs of the LapD-LapG c-di-GMP Effector System Control Biofilm Formation by Bordetella bronchiseptica

    Science.gov (United States)

    Ambrosis, Nicolás; Boyd, Chelsea D.; O´Toole, George A.; Fernández, Julieta; Sisti, Federico

    2016-01-01

    Biofilm formation is important for infection by many pathogens. Bordetella bronchiseptica causes respiratory tract infections in mammals and forms biofilm structures in nasal epithelium of infected mice. We previously demonstrated that cyclic di-GMP is involved in biofilm formation in B. bronchiseptica. In the present work, based on their previously reported function in Pseudomonas fluorescens, we identified three genes in the B. bronchiseptica genome likely involved in c-di-GMP-dependent biofilm formation: brtA, lapD and lapG. Genetic analysis confirmed a role for BrtA, LapD and LapG in biofilm formation using microtiter plate assays, as well as scanning electron and fluorescent microscopy to analyze the phenotypes of mutants lacking these proteins. In vitro and in vivo studies showed that the protease LapG of B. bronchiseptica cleaves the N-terminal domain of BrtA, as well as the LapA protein of P. fluorescens, indicating functional conservation between these species. Furthermore, while BrtA and LapG appear to have little or no impact on colonization in a mouse model of infection, a B. bronchiseptica strain lacking the LapG protease has a significantly higher rate of inducing a severe disease outcome compared to the wild type. These findings support a role for c-di-GMP acting through BrtA/LapD/LapG to modulate biofilm formation, as well as impact pathogenesis, by B. bronchiseptica PMID:27380521

  3. STING activator c-di-GMP enhances the anti-tumor effects of peptide vaccines in melanoma-bearing mice.

    Science.gov (United States)

    Wang, Zili; Celis, Esteban

    2015-08-01

    Therapeutic vaccines to induce anti-tumor CD8 T cells have been used in clinical trials for advanced melanoma patients, but the clinical response rate and overall survival time have not improved much. We believe that these dismal outcomes are caused by inadequate number of antigen-specific CD8 T cells generated by most vaccines. In contrast, huge CD8 T cell responses readily occur during acute viral infections. High levels of type-I interferon (IFN-I) are produced during these infections, and this cytokine not only exhibits anti-viral activity but also promotes CD8 T cell responses. The studies described here were performed to determine whether promoting the production of IFN-I could enhance the potency of a peptide vaccine. We report that cyclic diguanylate monophosphate (c-di-GMP), which activates the stimulator of interferon genes, potentiated the immunogenicity and anti-tumor effects of a peptide vaccine against mouse B16 melanoma. The synergistic effects of c-di-GMP required co-administration of costimulatory anti-CD40 antibody, the adjuvant poly-IC, and were mediated in part by IFN-I. These findings demonstrate that peptides representing CD8 T cell epitopes can be effective inducers of large CD8 T cell responses in vaccination strategies that mimic acute viral infections.

  4. In vitro and in vivo generation and characterization of Pseudomonas aeruginosa biofilm-dispersed cells via c-di-GMP manipulation.

    Science.gov (United States)

    Chua, Song Lin; Hultqvist, Louise D; Yuan, Mingjun; Rybtke, Morten; Nielsen, Thomas E; Givskov, Michael; Tolker-Nielsen, Tim; Yang, Liang

    2015-08-01

    Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a global secondary bacterial messenger that controls the formation of drug-resistant multicellular biofilms. Lowering the intracellular c-di-GMP content can disperse biofilms, and it is proposed as a biofilm eradication strategy. However, freshly dispersed biofilm cells exhibit a physiology distinct from biofilm and planktonic cells, and they might have a clinically relevant role in infections. Here we present in vitro and in vivo protocols for the generation and characterization of dispersed cells from Pseudomonas aeruginosa biofilms by reducing the intracellular c-di-GMP content through modulation of phosphodiesterases (PDEs). Unlike conventional protocols that demonstrate biofilm dispersal by biomass quantification, our protocols enable physiological characterization of the dispersed cells. Biomarkers of dispersed cells are identified and quantified, serving as potential targets for treating the dispersed cells. The in vitro protocol can be completed within 4 d, whereas the in vivo protocol requires 7 d.

  5. The exopolysaccharide gene cluster Bcam1330-Bcam1341 is involved in Burkholderia cenocepacia biofilm formation, and its expression is regulated by c-di-GMP and Bcam1349

    DEFF Research Database (Denmark)

    Fazli, Mustafa; McCarthy, Yvonne; Givskov, Michael

    2013-01-01

    In Burkholderia cenocepacia, the second messenger cyclic diguanosine monophosphate (c-di-GMP) has previously been shown to positively regulate biofilm formation and the expression of cellulose and type-I fimbriae genes through binding to the transcriptional regulator Bcam1349. Here, we provide...... evidence that cellulose and type-I fimbriae are not involved in B. cenocepacia biofilm formation in flow chambers, and we identify a novel Bcam1349/c-di-GMP-regulated exopolysaccharide gene cluster which is essential for B. cenocepacia biofilm formation. Overproduction of Bcam1349 in trans promotes wrinkly...... matrix exopolysaccharide and to be essential for flow-chamber biofilm formation. We demonstrate that Bcam1349 binds to the promoter region of genes in the Bcam1330-Bcam1341 cluster and that this binding is enhanced by the presence of c-di-GMP. Furthermore, we demonstrate that overproduction of both c...

  6. A flavin cofactor-binding PAS domain regulates c-di-GMP synthesis in AxDGC2 from Acetobacter xylinum.

    Science.gov (United States)

    Qi, Yaning; Rao, Feng; Luo, Zhen; Liang, Zhao-Xun

    2009-11-03

    The cytoplasmic protein AxDGC2 regulates cellulose synthesis in the obligate aerobe Acetobacter xylinum by controlling the cellular concentration of the cyclic dinucleotide messenger c-di-GMP. AxDGC2 contains a Per-Arnt-Sim (PAS) domain and two putative catalytic domains (GGDEF and EAL) for c-di-GMP metabolism. We found that the PAS domain of AxDGC2 binds a flavin adenine dinucleotide (FAD) cofactor noncovalently. The redox status of the FAD cofactor modulates the catalytic activity of the GGDEF domain for c-di-GMP synthesis, with the oxidized form exhibiting higher catalytic activity and stronger substrate inhibition. The results suggest that AxDGC2 is a signaling protein that regulates the cellular c-di-GMP level in response to the change in cellular redox status or oxygen concentration. Moreover, several residues predicated to be involved in FAD binding and signal transduction were mutated to examine the impact on redox potential and catalytic activity. Despite the minor perturbation of redox potential and unexpected modification of FAD in one of the mutants, none of the single mutations was able to completely disrupt the transmission of the signal to the GGDEF domain, indicating that the change in the FAD redox state can still trigger structural changes in the PAS domain probably by using substituted hydrogen-bonded water networks. Meanwhile, although the EAL domain of AxDGC2 was found to be catalytically inactive toward c-di-GMP, it was capable of hydrolyzing some phosphodiester bond-containing nonphysiological substrates. Together with the previously reported oxygen-dependent activity of the homologous AxPDEA1, the results provided new insight into relationships among oxygen level, c-di-GMP concentration, and cellulose synthesis in A. xylinum.

  7. In vitro and in vivo generation and characterization of Pseudomonas aeruginosa biofilm-dispersed cells via c-di-GMP manipulation

    DEFF Research Database (Denmark)

    Chua, Song Lin; Hultqvist, Louise D; Yuan, Mingjun;

    2015-01-01

    Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a global secondary bacterial messenger that controls the formation of drug-resistant multicellular biofilms. Lowering the intracellular c-di-GMP content can disperse biofilms, and it is proposed as a biofilm eradication strategy...

  8. Characterization of a natural triple-tandem c-di-GMP riboswitch and application of the riboswitch-based dual-fluorescence reporter.

    Science.gov (United States)

    Zhou, Hang; Zheng, Cao; Su, Jianmei; Chen, Bo; Fu, Yang; Xie, Yuqun; Tang, Qing; Chou, Shan-Ho; He, Jin

    2016-02-19

    c-di-GMP riboswitches are structured RNAs located in the 5'-untranslated regions (5'-UTRs) of mRNAs that regulate expression of downstream genes in response to changing concentrations of the second messenger c-di-GMP. We discovered three complete c-di-GMP riboswitches (Bc3, Bc4 and Bc5 RNA) with similar structures, which are arranged in tandem to constitute a triple-tandem (Bc3-5 RNA) riboswitch in the 5'-UTR of the cspABCDE mRNA in Bacillus thuringiensis subsp. chinensis CT-43. Our results showed that this natural triple-tandem riboswitch controlled the expression of the reporter gene more stringently and digitally than the double-tandem or single riboswitch. A sandwich-like dual-fluorescence reporter was further constructed by fusing the Bc3-5 RNA gene between the two fluorescence protein genes amcyan and turborfp. This reporter strain was found to exhibit detectable fluorescence color changes under bright field in response to intracellular c-di-GMP level altered by induced expression of diguanylate cyclase (DGC) PleD. Using this system, two putative membrane-bound DGCs from B. thuringiensis and Xanthomonas oryzae were verified to be functional by replacing pleD with the corresponding DGC genes. This report represented the first native triple-tandem riboswitch that was applied to serve as a riboswitch-based dual-fluorescence reporter for the efficient and convenient verification of putative DGC activity in vivo.

  9. The EAL domain protein YciR acts as a trigger enzyme in a c-di-GMP signalling cascade in E. coli biofilm control

    Science.gov (United States)

    Lindenberg, Sandra; Klauck, Gisela; Pesavento, Christina; Klauck, Eberhard; Hengge, Regine

    2013-01-01

    C-di-GMP—which is produced by diguanylate cyclases (DGC) and degraded by specific phosphodiesterases (PDEs)—is a ubiquitous second messenger in bacterial biofilm formation. In Escherichia coli, several DGCs (YegE, YdaM) and PDEs (YhjH, YciR) and the MerR-like transcription factor MlrA regulate the transcription of csgD, which encodes a biofilm regulator essential for producing amyloid curli fibres of the biofilm matrix. Here, we demonstrate that this system operates as a signalling cascade, in which c-di-GMP controlled by the DGC/PDE pair YegE/YhjH (module I) regulates the activity of the YdaM/YciR pair (module II). Via multiple direct interactions, the two module II proteins form a signalling complex with MlrA. YciR acts as a connector between modules I and II and functions as a trigger enzyme: its direct inhibition of the DGC YdaM is relieved when it binds and degrades c-di-GMP generated by module I. As a consequence, YdaM then generates c-di-GMP and—by direct and specific interaction—activates MlrA to stimulate csgD transcription. Trigger enzymes may represent a general principle in local c-di-GMP signalling. PMID:23708798

  10. MrkH, a novel c-di-GMP-dependent transcriptional activator, controls Klebsiella pneumoniae biofilm formation by regulating type 3 fimbriae expression.

    Directory of Open Access Journals (Sweden)

    Jonathan J Wilksch

    2011-08-01

    Full Text Available Klebsiella pneumoniae causes significant morbidity and mortality worldwide, particularly amongst hospitalized individuals. The principle mechanism for pathogenesis in hospital environments involves the formation of biofilms, primarily on implanted medical devices. In this study, we constructed a transposon mutant library in a clinical isolate, K. pneumoniae AJ218, to identify the genes and pathways implicated in biofilm formation. Three mutants severely defective in biofilm formation contained insertions within the mrkABCDF genes encoding the main structural subunit and assembly machinery for type 3 fimbriae. Two other mutants carried insertions within the yfiN and mrkJ genes, which encode GGDEF domain- and EAL domain-containing c-di-GMP turnover enzymes, respectively. The remaining two isolates contained insertions that inactivated the mrkH and mrkI genes, which encode for novel proteins with a c-di-GMP-binding PilZ domain and a LuxR-type transcriptional regulator, respectively. Biochemical and functional assays indicated that the effects of these factors on biofilm formation accompany concomitant changes in type 3 fimbriae expression. We mapped the transcriptional start site of mrkA, demonstrated that MrkH directly activates transcription of the mrkA promoter and showed that MrkH binds strongly to the mrkA regulatory region only in the presence of c-di-GMP. Furthermore, a point mutation in the putative c-di-GMP-binding domain of MrkH completely abolished its function as a transcriptional activator. In vivo analysis of the yfiN and mrkJ genes strongly indicated their c-di-GMP-specific function as diguanylate cyclase and phosphodiesterase, respectively. In addition, in vitro assays showed that purified MrkJ protein has strong c-di-GMP phosphodiesterase activity. These results demonstrate for the first time that c-di-GMP can function as an effector to stimulate the activity of a transcriptional activator, and explain how type 3 fimbriae

  11. Differential control of Yersinia pestis biofilm formation in vitro and in the flea vector by two c-di-GMP diguanylate cyclases.

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    Yi-Cheng Sun

    Full Text Available Yersinia pestis forms a biofilm in the foregut of its flea vector that promotes transmission by flea bite. As in many bacteria, biofilm formation in Y. pestis is controlled by intracellular levels of the bacterial second messenger c-di-GMP. Two Y. pestis diguanylate cyclase (DGC enzymes, encoded by hmsT and y3730, and one phosphodiesterase (PDE, encoded by hmsP, have been shown to control biofilm production in vitro via their opposing c-di-GMP synthesis and degradation activities, respectively. In this study, we provide further evidence that hmsT, hmsP, and y3730 are the only three genes involved in c-di-GMP metabolism in Y. pestis and evaluated the two DGCs for their comparative roles in biofilm formation in vitro and in the flea vector. As with HmsT, the DGC activity of Y3730 depended on a catalytic GGDEF domain, but the relative contribution of the two enzymes to the biofilm phenotype was influenced strongly by the environmental niche. Deletion of y3730 had a very minor effect on in vitro biofilm formation, but resulted in greatly reduced biofilm formation in the flea. In contrast, the predominant effect of hmsT was on in vitro biofilm formation. DGC activity was also required for the Hms-independent autoaggregation phenotype of Y. pestis, but was not required for virulence in a mouse model of bubonic plague. Our results confirm that only one PDE (HmsP and two DGCs (HmsT and Y3730 control c-di-GMP levels in Y. pestis, indicate that hmsT and y3730 are regulated post-transcriptionally to differentially control biofilm formation in vitro and in the flea vector, and identify a second c-di-GMP-regulated phenotype in Y. pestis.

  12. 环二鸟苷酸(c-di-GMP)在微生物体内的作用及其类似物的研究%Activity of cyclic diguanylate (c-di-GMP) in bacteria and the study of its derivatives

    Institute of Scientific and Technical Information of China (English)

    那路新; 杨振军

    2012-01-01

    环二鸟苷酸(cyclic diguanylate,c-di-GMP)是在细菌中普遍存在的第二信使分子,参与调节多种生理功能,包括细胞分化、生物被膜形成、致病因子产生等.细菌细胞内c-di-GMP合成与降解代谢分别受二鸟苷酸环化酶(diguanylate cyclase,DGC)和磷酸二酯酶(phosphodiesterase,PDE)调控,DGC和PDE共处于同一个蛋白中,是一个双功能蛋白酶的两个区域,分别负责菌体内c-di-GMP的合成和降解.c-di-GMP作用菌体内下游靶点包括PilZ结构域和GEMM核开关两种类型.目前发现c-di-GMP核开关是唯一不参与代谢活动而参与信号传导的一类核开关.本文综述了c-di-GMP的代谢途径、调控机制、生物学功能,以及c-di-GMP结构类似物合成及生物学评价等方面的最新研究进展.%Cyclic diguanylate (c-di-GMP) is a ubiquitous second messenger present in a wide variety of bacteria, which is responsible for cell differentiation, biofilm formation, pathogenic factor generation, and so on. The level of c-di-GMP in bacteria is regulated by two opposing active domains, diguanylate cyclase (DGC) and phosphodiesterase (PDE), which are present in the same bifunctional protein, and in charge of the synthesis and the degradation of c-di-GMP, respectively. The target of c-di-GMP in the bacterial cell consists of PilZ domain and GEMM riboswitch, the only riboswitch that involved in signal transduction. This article gives an overview of c-di-GMP, focusing on its metabolic pathway, regulatory mechanism, biological function of c-di-GMP, and the synthesis of c-di-GMP analogues and their biological activity.

  13. Three cyanobacteriochromes work together to form a light color-sensitive input system for c-di-GMP signaling of cell aggregation.

    Science.gov (United States)

    Enomoto, Gen; Ni-Ni-Win; Narikawa, Rei; Ikeuchi, Masahiko

    2015-06-30

    Cyanobacteriochromes (CBCRs) are cyanobacterial photoreceptors that have diverse spectral properties and domain compositions. Although large numbers of CBCR genes exist in cyanobacterial genomes, no studies have assessed whether multiple CBCRs work together. We recently showed that the diguanylate cyclase (DGC) activity of the CBCR SesA from Thermosynechococcus elongatus is activated by blue-light irradiation and that, when irradiated, SesA, via its product cyclic dimeric GMP (c-di-GMP), induces aggregation of Thermosynechococcus vulcanus cells at a temperature that is suboptimum for single-cell viability. For this report, we first characterize the photobiochemical properties of two additional CBCRs, SesB and SesC. Blue/teal light-responsive SesB has only c-di-GMP phosphodiesterase (PDE) activity, which is up-regulated by teal light and GTP. Blue/green light-responsive SesC has DGC and PDE activities. Its DGC activity is enhanced by blue light, whereas its PDE activity is enhanced by green light. A ΔsesB mutant cannot suppress cell aggregation under teal-green light. A ΔsesC mutant shows a less sensitive cell-aggregation response to ambient light. ΔsesA/ΔsesB/ΔsesC shows partial cell aggregation, which is accompanied by the loss of color dependency, implying that a nonphotoresponsive DGC(s) producing c-di-GMP can also induce the aggregation. The results suggest that SesB enhances the light color dependency of cell aggregation by degrading c-di-GMP, is particularly effective under teal light, and, therefore, seems to counteract the induction of cell aggregation by SesA. In addition, SesC seems to improve signaling specificity as an auxiliary backup to SesA/SesB activities. The coordinated action of these three CBCRs highlights why so many different CBCRs exist.

  14. Evaluation of a Salmonella Strain Lacking the Secondary Messenger C-di-GMP and RpoS as a Live Oral Vaccine

    Science.gov (United States)

    García, Begoña; Gil, Carmen; García-Ona, Enrique; Burgui, Saioa; Casares, Noelia; Hervás-Stubbs, Sandra; Lasarte, Juan José; Lasa, Iñigo

    2016-01-01

    Salmonellosis is one of the most important bacterial zoonotic diseases transmitted through the consumption of contaminated food, with chicken and pig related products being key reservoirs of infection. Although numerous studies on animal vaccination have been performed in order to reduce Salmonella prevalence, there is still a need for an ideal vaccine. Here, with the aim of constructing a novel live attenuated Salmonella vaccine candidate, we firstly analyzed the impact of the absence of cyclic-di-GMP (c-di-GMP) in Salmonella virulence. C-di-GMP is an intracellular second messenger that controls a wide range of bacterial processes, including biofilm formation and synthesis of virulence factors, and also modulates the host innate immune response. Our results showed that a Salmonella multiple mutant in the twelve genes encoding diguanylate cyclase proteins that, as a consequence, cannot synthesize c-di-GMP, presents a moderate attenuation in a systemic murine infection model. An additional mutation of the rpoS gene resulted in a synergic attenuating effect that led to a highly attenuated strain, referred to as ΔXIII, immunogenic enough to protect mice against a lethal oral challenge of a S. Typhimurium virulent strain. ΔXIII immunogenicity relied on activation of both antibody and cell mediated immune responses characterized by the production of opsonizing antibodies and the induction of significant levels of IFN-γ, TNF-α, IL-2, IL-17 and IL-10. ΔXIII was unable to form a biofilm and did not survive under desiccation conditions, indicating that it could be easily eliminated from the environment. Moreover, ΔXIII shows DIVA features that allow differentiation of infected and vaccinated animals. Altogether, these results show ΔXIII as a safe and effective live DIVA vaccine. PMID:27537839

  15. E88, a new cyclic-di-GMP class I riboswitch aptamer from Clostridium tetani, has a similar fold to the prototypical class I riboswitch, Vc2, but differentially binds to c-di-GMP analogs.

    Science.gov (United States)

    Luo, Yiling; Chen, Bin; Zhou, Jie; Sintim, Herman O; Dayie, T Kwaku

    2014-03-04

    C-di-GMP has emerged as a ubiquitous second messenger, which regulates the transition between sessile and motile lifestyles and virulence factor expression in many pathogenic bacteria using both RNA riboswitches and protein effectors. We recently showed that two additional class I c-di-GMP riboswitch aptamers (Ct-E88 and Cb-17B) bind c-di-GMP with nanomolar affinity, and that Ct-E88 RNA binds 2'-F-c-di-GMP 422 times less tightly than class I Vc2 RNA. Based on sequence comparison, it was concluded that the global folds of Ct-E88 and Vc2 RNAs were similar and that differences in ligand binding were probably due to differences in binding site architectures. Herein, we utilized EMSA, aptamer sensing spinach modules, SAXS and 1D NMR titration to study the conformational transitions of Ct-E88. We conclude that whereas the global folds of the bound states of Vc2 and Ct-E88 RNAs are similar, the unbound states are different and this could explain differences in ligand affinities between these class I c-di-GMP riboswitches.

  16. Evaluation of the sublingual route for administration of influenza H5N1 virosomes in combination with the bacterial second messenger c-di-GMP.

    Directory of Open Access Journals (Sweden)

    Gabriel Kristian Pedersen

    Full Text Available Avian influenza A H5N1 is a virus with pandemic potential. Mucosal vaccines are attractive as they have the potential to block viruses at the site of entry, thereby preventing both disease and further transmission. The intranasal route is safe for the administration of seasonal live-attenuated influenza vaccines, but may be less suitable for administration of pandemic vaccines. Research into novel mucosal routes is therefore needed. In this study, a murine model was used to compare sublingual administration with intranasal and intramuscular administration of influenza H5N1 virosomes (2 µg haemagglutinin; HA in combination with the mucosal adjuvant (3',5'-cyclic dimeric guanylic acid (c-di-GMP. We found that sublingual immunisation effectively induced local and systemic H5N1-specific humoral and cellular immune responses but that the magnitude of response was lower than after intranasal administration. However, both the mucosal routes were superior to intramuscular immunisation for induction of local humoral and systemic cellular immune responses including high frequencies of splenic H5N1-specific multifunctional (IL-2+TNF-α+ CD4+ T cells. The c-di-GMP adjuvanted vaccine elicited systemic haemagglutination inhibition (HI antibody responses (geometric mean titres ≥ 40 both when administered sublingually, intranasally and inramuscularly. In addition, salivary HI antibodies were elicited by mucosal, but not intramuscular vaccination. We conclude that the sublingual route is an attractive alternative for administration of pandemic influenza vaccines.

  17. Evaluation of the sublingual route for administration of influenza H5N1 virosomes in combination with the bacterial second messenger c-di-GMP.

    Science.gov (United States)

    Pedersen, Gabriel Kristian; Ebensen, Thomas; Gjeraker, Ingrid Hjetland; Svindland, Signe; Bredholt, Geir; Guzmán, Carlos Alberto; Cox, Rebecca Jane

    2011-01-01

    Avian influenza A H5N1 is a virus with pandemic potential. Mucosal vaccines are attractive as they have the potential to block viruses at the site of entry, thereby preventing both disease and further transmission. The intranasal route is safe for the administration of seasonal live-attenuated influenza vaccines, but may be less suitable for administration of pandemic vaccines. Research into novel mucosal routes is therefore needed. In this study, a murine model was used to compare sublingual administration with intranasal and intramuscular administration of influenza H5N1 virosomes (2 µg haemagglutinin; HA) in combination with the mucosal adjuvant (3',5')-cyclic dimeric guanylic acid (c-di-GMP). We found that sublingual immunisation effectively induced local and systemic H5N1-specific humoral and cellular immune responses but that the magnitude of response was lower than after intranasal administration. However, both the mucosal routes were superior to intramuscular immunisation for induction of local humoral and systemic cellular immune responses including high frequencies of splenic H5N1-specific multifunctional (IL-2+TNF-α+) CD4+ T cells. The c-di-GMP adjuvanted vaccine elicited systemic haemagglutination inhibition (HI) antibody responses (geometric mean titres ≥ 40) both when administered sublingually, intranasally and inramuscularly. In addition, salivary HI antibodies were elicited by mucosal, but not intramuscular vaccination. We conclude that the sublingual route is an attractive alternative for administration of pandemic influenza vaccines.

  18. Activation and polar sequestration of PopA, a c-di-GMP effector protein involved in Caulobacter crescentus cell cycle control.

    Science.gov (United States)

    Ozaki, Shogo; Schalch-Moser, Annina; Zumthor, Ludwig; Manfredi, Pablo; Ebbensgaard, Anna; Schirmer, Tilman; Jenal, Urs

    2014-11-01

    When Caulobacter crescentus enters S-phase the replication initiation inhibitor CtrA dynamically positions to the old cell pole to be degraded by the polar ClpXP protease. Polar delivery of CtrA requires PopA and the diguanylate cyclase PleD that positions to the same pole. Here we present evidence that PopA originated through gene duplication from its paralogue response regulator PleD and subsequent co-option as c-di-GMP effector protein. While the C-terminal catalytic domain (GGDEF) of PleD is activated by phosphorylation of the N-terminal receiver domain, functional adaptation has reversed signal transduction in PopA with the GGDEF domain adopting input function and the receiver domain serving as regulatory output. We show that the N-terminal receiver domain of PopA specifically interacts with RcdA, a component required for CtrA degradation. In contrast, the GGDEF domain serves to target PopA to the cell pole in response to c-di-GMP binding. In agreement with the divergent activation and targeting mechanisms, distinct markers sequester PleD and PopA to the old cell pole upon S-phase entry. Together these data indicate that PopA adopted a novel role as topology specificity factor to help recruit components of the CtrA degradation pathway to the protease specific old cell pole of C. crescentus.

  19. A cyclic dinucleotide containing 2-aminopurine is a general fluorescent sensor for c-di-GMP and 3',3'-cGAMP.

    Science.gov (United States)

    Roembke, Benjamin T; Zhou, Jie; Zheng, Yue; Sayre, David; Lizardo, Allan; Bernard, Laurentee; Sintim, Herman O

    2014-06-01

    Cyclic dinucleotides have emerged as second messengers that regulate diverse processes in bacteria, as well as regulating the production of type I interferons in metazoans. Fluorescent sensors for these important second messengers are highly sought-after for high-throughput inhibitor discovery, yet most sensors reported to date are not amenable for high-throughput screening purposes. Herein, we demonstrate that a new analog, 3',3'-cG(d2AP)MP, which is a 2-aminopurine (2AP)-containing cyclic dinucleotide, self-associates in the presence of Mn(2+) with an association constant of 120,000 M(-1). 3'3'-cG(d2AP)MP can also form a heterodimer with cGAMP, activator of immune regulator, STING, or the bacterial biofilm regulator, c-di-GMP in the presence of Mn(II). Upon dimer formation, the fluorescence of 3',3'-cG(d2AP)MP is quenched and this provides a convenient method to monitor the enzymatic processing of both DGC and PDE enzymes, opening up several opportunities for the discovery of inhibitors of nucleotide signaling.

  20. The REC domain mediated dimerization is critical for FleQ from Pseudomonas aeruginosa to function as a c-di-GMP receptor and flagella gene regulator.

    Science.gov (United States)

    Su, Tiantian; Liu, Shiheng; Wang, Kang; Chi, Kaikai; Zhu, Deyu; Wei, Tiandi; Huang, Yan; Guo, Liming; Hu, Wei; Xu, Sujuan; Lin, Zong; Gu, Lichuan

    2015-10-01

    FleQ is an AAA+ ATPase enhancer-binding protein that regulates both flagella and biofilm formation in the opportunistic pathogen Pseudomonas aeruginosa. FleQ belongs to the NtrC subfamily of response regulators, but lacks the corresponding aspartic acid for phosphorylation in the REC domain (FleQ(R), also named FleQ domain). Here, we show that the atypical REC domain of FleQ is essential for the function of FleQ. Crystal structure of FleQ(R) at 2.3Å reveals that the structure of FleQ(R) is significantly different from the REC domain of NtrC1 which regulates gene expression in a phosphorylation dependent manner. FleQ(R) forms a novel active dimer (transverse dimer), and mediates the dimerization of full-length FleQ in an unusual manner. Point mutations that affect the dimerization of FleQ lead to loss of function of the protein. Moreover, a c-di-GMP binding site deviating from the previous reported one is identified through structure analysis and point mutations.

  1. A novel two-component system PdeK/PdeR regulates c-di-GMP turnover and virulence of Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Yang, Fenghuan; Tian, Fang; Sun, Lei; Chen, Huamin; Wu, Maosen; Yang, Ching-Hong; He, Chenyang

    2012-10-01

    Two-component systems (TCS) consisting of histidine kinases (HK) and response regulators (RR) play essential roles in bacteria to sense environmental signals and regulate cell functions. One type of RR is involved in metabolism of cyclic diguanylate (c-di-GMP), a ubiquitous bacterial second messenger. Although genomic studies predicted a large number of them existing in different bacteria, only a few have been studied. In this work, we characterized a novel TCS consisting of PdeK(PXO_01018)/PdeR(PXO_ 01019) from Xanthomonas oryzae pv. oryzae, which causes the bacterial leaf blight of rice. PdeR (containing GGDEF, EAL, and REC domains) was shown to have phosphodiesterase (PDE) activity in vitro by colorimetric assays and high-performance liquid chromatography analysis. The PDE activity of full-length PdeR needs to be triggered by HK PdeK. Deletion of pdeK or pdeR in X. oryzae pv. oryzae PXO99(A) had attenuated its virulence on rice. ΔpdeK and ΔpdeR secreted less exopolysaccharide than the wild type but there were no changes in terms of motility or extracellular cellulase activity, suggesting the activity of PdeK/PdeR might be specific.

  2. Transcriptional activation of the mrkA promoter of the Klebsiella pneumoniae type 3 fimbrial operon by the c-di-GMP-dependent MrkH protein.

    Directory of Open Access Journals (Sweden)

    Ji Yang

    Full Text Available The Gram-negative bacterial pathogen Klebsiella pneumoniae forms biofilms to facilitate colonization of biotic and abiotic surfaces. The formation of biofilms by K. pneumoniae requires the expression of type 3 fimbriae: elongate proteinaceous filaments extruded by a chaperone-usher system in the bacterial outer membrane. The expression of the mrkABCDF cluster that encodes this fimbrial system is strongly positively regulated by MrkH, a transcriptional activator that responds to the second messenger, c-di-GMP. In this study, we analyzed the mechanism by which the MrkH protein activates transcriptional initiation from the mrkA promoter. A mutational analysis supported by electrophoretic mobility shift assays demonstrated that a 12-bp palindromic sequence (the MrkH box centered at -78.5 is the binding site of MrkH. Deletion of half a turn, but not a full turn, of DNA located between the MrkH box and the mrkA promoter destroyed the ability of MrkH to activate mrkA transcription. In addition, a 10-bp AT-rich sequence (the UP element centered at -63.5 contributed significantly to MrkH-dependent mrkA transcription. In vivo analysis of rpoA mutants showed that the R265 and E273 determinants in the C-terminal domain of RNA polymerase α subunit are needed for MrkH-mediated activation of mrkA transcription. Furthermore, results from mutagenesis of the mrkH gene suggest that the N-terminal region of the protein is involved in transcriptional activation. Taken together, our results suggest that MrkH activates mrkA expression by interacting directly with RNA polymerase, to overcome the inefficient transcriptional initiation caused by the presence of defective core promoter elements.

  3. Correlation study between c-di-GMP and biofilm formation by Pseudomonas aeruginosa%环二鸟苷酸与铜绿假单胞菌形成生物膜的相关性研究

    Institute of Scientific and Technical Information of China (English)

    王岚; 刘新; 吴怡; 方芳

    2012-01-01

    Objective To investigate the correlation between c-di-GMP and biofilm formation by Pseudomonas aeruginosa through constructing strains with phospho-diesterase gene mutation. Methods The plasmid for genetic mutation was constructed with gene engineering technique and transformed into wild Pseudomonas aeruginosa by homologous recombination. The genetic mutation strains were screened by resistance and sucrose. Results Compared with wild strains, the genetic mutation strains were more prone to form microclone and biofilm on catheter material. Conclusion The increase of c-di-GMP can promotes biofilm formation. C-di-GMP has closely correlation with nosocomial infection and drug resistance caused by Pseudomonas aeruginosa.%目的:通过构建环二鸟苷酸降解酶磷脂酶D基因突变株,探讨环二鸟苷酸与铜绿假单胞菌形成生物膜的相关性.方法:采用基因工程技术构建磷脂酶D基因突变质粒,通过同源重组转化至野生型铜绿假单胞菌PA01,抗性筛选获得基因突变株bf-.扫描电子显微镜下观察基因突变株与野生菌株生物膜表型的差异.结果:与野生菌株相比,基因突变株bf-细菌微克隆的形成增加,有利于细菌在导管材料表面形成生物膜.结论:环二鸟苷酸的增加可促进细菌生物膜的形成,与铜绿假单胞菌引起的院内感染和耐药性密切相关.

  4. The Bacterial Second Messenger c-di-GMP Metabolism Regulation and the Roles of Virulence%细菌第二信使c-di-GMP的代谢调控及在致病性中的作用

    Institute of Scientific and Technical Information of China (English)

    魏超; 杨军; 张元宝; 王磊; 孙文献; 王云月

    2013-01-01

    环鸟苷二磷酸(cyclic diguanylate,c-di-GMP)是细菌内广泛存在的一类全新的第二信使分子.具有鸟苷酸环化酶(diguanylate cyclase,DGC)活性的GGDEF结构域蛋白以及具有磷酸二酯酶(phosphodiesterases,PDE)活性的EAL或HD-GYP结构域蛋白分别负责c-di-GMP的合成与降解.细菌内存在多种类型c-di-GMP的受体,负责感知细胞内c-di-GMP浓度的变化,并启动或抑制下游特定基因的表达.这些受体包括PilZ结构域蛋白,退化的GGDEF和EAL结构域蛋白,转录因子以及核糖开关(riboswitch).c-di-GMP参与调控细菌的多种生物学功能,如生物膜形成、运动性、胞外多糖的合成、胞外酶的分泌和三型分泌系统等,从而影响病原细菌的致病性.本文对近期c-di-GMP相关研究进展进行综述,并就其应用前景进行了讨论.

  5. Capsaicin triggers immunogenic PEL cell death, stimulates DCs and reverts PEL-induced immune suppression.

    Science.gov (United States)

    Granato, Marisa; Gilardini Montani, Maria Saveria; Filardi, Mariarosari; Faggioni, Alberto; Cirone, Mara

    2015-10-06

    Capsaicin, the pungent alkaloid of red pepper has been extensively studied for its many properties, especially the anti-inflammatory and anti-oxidant ones. It binds to vanilloid receptor 1, although it has been reported to be able to mediate some effects independently of its receptor. Another important property of Capsaicin is the anticancer activity against highly malignant tumors, alone or in combination with other chemotherapeutic agents. In this study, we found that Capsaicin induced an apoptotic cell death in PEL cells correlated with the inhibition of STAT3. STAT3 pathway, constitutively activated in PEL cells, is essential for their survival. By STAT3 de-phosphorylation, Capsaicin reduced the Mcl-1 expression level and this could represent one of the underlying mechanisms leading to the Capsaicin-mediated cell death and autophagy induction. Next, by pharmacological or genetic inhibition, we found that autophagy played a pro-survival role, suggesting that its inhibition could be exploited to increase the Capsaicin cytotoxic effect against PEL cells. Finally, we show that Capsaicin induced DAMP exposure, as for an immunogenic cell death, directly promoted DC activation and, more importantly, that it counteracted the immune-suppression, in terms of DC differentiation, mediated by the PEL released factors.

  6. Oligoribonuclease is the primary degradative enzyme for pGpG in Pseudomonas aeruginosa that is required for cyclic-di-GMP turnover.

    Science.gov (United States)

    Orr, Mona W; Donaldson, Gregory P; Severin, Geoffrey B; Wang, Jingxin; Sintim, Herman O; Waters, Christopher M; Lee, Vincent T

    2015-09-01

    The bacterial second messenger cyclic di-GMP (c-di-GMP) controls biofilm formation and other phenotypes relevant to pathogenesis. Cyclic-di-GMP is synthesized by diguanylate cyclases (DGCs). Phosphodiesterases (PDE-As) end signaling by linearizing c-di-GMP to 5'-phosphoguanylyl-(3',5')-guanosine (pGpG), which is then hydrolyzed to two GMP molecules by yet unidentified enzymes termed PDE-Bs. We show that pGpG inhibits a PDE-A from Pseudomonas aeruginosa. In a dual DGC and PDE-A reaction, excess pGpG extends the half-life of c-di-GMP, indicating that removal of pGpG is critical for c-di-GMP homeostasis. Thus, we sought to identify the PDE-B enzyme(s) responsible for pGpG degradation. A differential radial capillary action of ligand assay-based screen for pGpG binding proteins identified oligoribonuclease (Orn), an exoribonuclease that hydrolyzes two- to five-nucleotide-long RNAs. Purified Orn rapidly converts pGpG into GMP. To determine whether Orn is the primary enzyme responsible for degrading pGpG, we assayed cell lysates of WT and ∆orn strains of P. aeruginosa PA14 for pGpG stability. The lysates from ∆orn showed 25-fold decrease in pGpG hydrolysis. Complementation with WT, but not active site mutants, restored hydrolysis. Accumulation of pGpG in the ∆orn strain could inhibit PDE-As, increasing c-di-GMP concentration. In support, we observed increased transcription from the c-di-GMP-regulated pel promoter. Additionally, the c-di-GMP-governed auto-aggregation and biofilm phenotypes were elevated in the ∆orn strain in a pel-dependent manner. Finally, we directly detect elevated pGpG and c-di-GMP in the ∆orn strain. Thus, we identified that Orn serves as the primary PDE-B enzyme that removes pGpG, which is necessary to complete the final step in the c-di-GMP degradation pathway.

  7. Polysaccharide Degradation

    Science.gov (United States)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  8. Expression of bvg-repressed genes in Bordetella pertussis is controlled by RisA through a novel c-di-GMP signaling pathway

    Science.gov (United States)

    The BvgAS two component system of Bordetella pertussis controls virulence factor expression. In addition, BvgAS controls expression of the bvg-repressed genes through the action of the repressor, BvgR. The transcription factor RisA is inhibited by BvgR, and when BvgR is not expressed RisA induces th...

  9. Activation and polar sequestration of PopA, a c-di-GMP effector protein involved in Caulobacter crescentus cell cycle control

    DEFF Research Database (Denmark)

    Ozaki, Shogo; Schalch-Moser, Annina; Zumthor, Ludwig;

    2014-01-01

    When Caulobacter crescentus enters S-phase the replication initiation inhibitor CtrA dynamically positions to the old cell pole to be degraded by the polar ClpXP protease. Polar delivery of CtrA requires PopA and the diguanylate cyclase PleD that positions to the same pole. Here we present evidence...

  10. Susceptibility of KSHV-Infected PEL Cell Lines to the Human Complement System.

    Science.gov (United States)

    Yoo, Seung-Min; Jeon, Hyungtaek; Lee, Suhyuk; Lee, Myung-Shin

    2016-03-01

    Pleural effusion lymphoma (PEL) is a rare B-cell lymphoma that has a very poor prognosis with a median survival time of around 6 months. PEL is caused by Kaposi's sarcoma-associated herpesvirus, and is often co-infected with the Epstein Barr virus. The complement system is fundamental in the innate immune system against pathogen invasion and tumor development. In the present study, we investigated the activation of the complement system in PEL cells using human serum complements. Interestingly, two widely used PEL cell lines, BCP-1 and BCBL-1, showed different susceptibility to the complement system, which may be due to CD46 expression on their cell membranes. Complement activation did not induce apoptosis but supported cell survival considerably. Our results demonstrated the susceptibility of PEL to the complement system and its underlying mechanisms, which would provide insight into understanding the pathogenesis of PEL.

  11. 24 CFR 990.165 - Computation of project expense level (PEL).

    Science.gov (United States)

    2010-04-01

    .... After the PEL in year 2000 dollars is created, the annual inflation factor as described in paragraph (d... as reported for FFY 2003 in a PUM amount. (d) Annual inflation factor. The PEL for each project shall be adjusted annually, beginning in 2005, by the local inflation factor. The local inflation...

  12. Output targets and transcriptional regulation by a cyclic dimeric GMP-responsive circuit in the Vibrio parahaemolyticus Scr network.

    Science.gov (United States)

    Ferreira, Rosana B R; Chodur, Daniel M; Antunes, Luis Caetano M; Trimble, Michael J; McCarter, Linda L

    2012-03-01

    The Vibrio parahaemolyticus Scr system modulates decisions pertinent to surface colonization by affecting the cellular level of cyclic dimeric GMP (c-di-GMP). In this work, we explore the scope and mechanism of this regulation. Transcriptome comparison of ΔscrABC and wild-type strains revealed expression differences with respect to ∼100 genes. Elevated c-di-GMP repressed genes in the surface-sensing regulon, including those encoding the lateral flagellar and type III secretion systems and N-acetylglucosamine-binding protein GpbA while inducing genes encoding other cell surface molecules and capsular polysaccharide. The transcription of a few regulatory genes was also affected, and the role of one was characterized. Mutations in cpsQ suppressed the sticky phenotype of scr mutants. cpsQ encodes one of four V. parahaemolyticus homologs in the CsgD/VpsT family, members of which have been implicated in c-di-GMP signaling. Here, we demonstrate that CpsQ is a c-di-GMP-binding protein. By using a combination of mutant and reporter analyses, CpsQ was found to be the direct, positive regulator of cpsA transcription. This c-di-GMP-responsive regulatory circuit could be reconstituted in Escherichia coli, where a low level of this nucleotide diminished the stability of CpsQ. The molecular interplay of additional known cps regulators was defined by establishing that CpsS, another CsgD family member, repressed cpsR, and the transcription factor CpsR activated cpsQ. Thus, we are developing a connectivity map of the Scr decision-making network with respect to its wiring and output strategies for colonizing surfaces and interaction with hosts; in doing so, we have isolated and reproduced a c-di-GMP-sensitive regulatory module in the circuit.

  13. Overview of the activity of a Brucella abortus preparation, Bru-Pel.

    Science.gov (United States)

    Youngner, J S; Feingold, D S; Keleti, G

    1978-11-01

    The properties of a nonviable, aqueous ether-extracted Brucela abortus preparation, Bru-Pel, are described. In addition to inducing a "virus-type" interferon response and protecting mice against challenge with otherwise lethal doses of Semliki Forest virus, Bru-Pel is demonstrated to have potent antitumor properties in mice. These antitumor effects appear to be mediated by an increase in nonspecific resistance similar to that seen with other experimental antitumor agents.

  14. Síntesis y caracterización de películas delgadas semiconductoras

    OpenAIRE

    GARCÍA MÉNDEZ, MANUEL; MORALES RODRÍGUEZ, SANTOS

    2013-01-01

    En este trabajo se presentan los resultados de una investigación que consistió en el depósito y crecimiento de películas delgadas de nitruro de aluminio (aln) empleando la técnica de erosión iónica reactiva por corriente directa (Dc). Se describe el análisis experimental de las propiedades estructurales de las películas.

  15. Membrane-anchored MucR mediates nitrate-dependent regulation of alginate production in Pseudomonas aeruginosa

    KAUST Repository

    Wang, Yajie

    2015-04-29

    Alginates exhibit unique material properties suitable for medical and industrial applications. However, if produced by Pseudomonas aeruginosa, it is an important virulence factor in infection of cystic fibrosis patients. The alginate biosynthesis machinery is activated by c-di-GMP imparted by the inner membrane protein, MucR. Here, it was shown that MucR impairs alginate production in response to nitrate in P. aeruginosa. Subsequent site-specific mutagenesis of MucR revealed that the second MHYT sensor motif (MHYT II, amino acids 121–124) of MucR sensor domain was involved in nitrate sensing. We also showed that both c-di-GMP synthesizing and degrading active sites of MucR were important for alginate production. Although nitrate and deletion of MucR impaired alginate promoter activity and global c-di-GMP levels, alginate yields were not directly correlated with alginate promoter activity or c-di-GMP levels, suggesting that nitrate and MucR modulate alginate production at a post-translational level through a localized pool of c-di-GMP. Nitrate increased pel promoter activity in the mucR mutant while in the same mutant the psl promoter activity was independent of nitrate. Nitrate and deletion of mucR did not impact on swarming motility but impaired attachment to solid surfaces. Nitrate and deletion of mucR promoted the formation of biofilms with increased thickness, cell density, and survival. Overall, this study provided insight into the functional role of MucR with respect to nitrate-mediated regulation of alginate biosynthesis. © 2015 Springer-Verlag Berlin Heidelberg

  16. Pedro Peláez, líder del clero filipino

    Directory of Open Access Journals (Sweden)

    Blanco Andrés, Roberto

    2011-12-01

    Full Text Available This article provides new information on the creole Filipino, Fr. Pedro Pablo Peláez, who, together with Fr. José Burgos, was the most outstanding clergyman in the nineteenth-century Philippines. It discusses Father Peláez’s previously unknown activities in the cabildo of the Manila Cathedral, where he was its most distinguished member. It analyzes his reformist ideas, and explains his work and strategy to defend the Filipino secular clergy, whose rights were being violated by the royal orders of 1848 and 1861. Against the reactionary religious orders, Peláez had a detailed modus operandi to defend the legitimacy of native priests’ control of parishes. Although his activities were cut short by his unexpected death in the earthquake of June 1863, Peláez served as an inspiration to be emulated.

    En este trabajo se intentan aportar algunas claves y datos inéditos sobre la biografía del presbítero criollo filipino Pedro Pablo Peláez, que es, junto con el P. José Burgos, el eclesiástico más destacado de la iglesia de Filipinas del siglo XIX. El trabajo aborda la totalmente desconocida actividad del P. Peláez en el cabildo de la catedral de Manila, donde acabaría siendo con el tiempo su hombre más insigne. Igualmente se analiza el espíritu e ideario reformista de Peláez y sus trabajos y estrategia para defender al clero secular filipino, cuyos derechos estaban siendo vulnerados por una serie de Reales Órdenes (1848 ó 1861 y la actitud reaccionaria de un sector de las órdenes religiosas. Peláez supo articular un modus operandi minucioso y muy efectivo en torno a la legitimidad de los curas filipinos en la dirección de las parroquias del país. Aunque sus actividades cesaron con su inesperada muerte en el terremoto de junio de 1863, Peláez se convirtió en una inspiración y un modelo a seguir.

  17. Systematic analysis of a xenograft mice model for KSHV+ primary effusion lymphoma (PEL.

    Directory of Open Access Journals (Sweden)

    Lu Dai

    Full Text Available Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL, which arises preferentially in the setting of infection with human immunodeficiency virus (HIV. Even with standard cytotoxic chemotherapy, PEL continues to cause high mortality rates, requiring the development of novel therapeutic strategies. PEL xenograft models employing immunodeficient mice have been used to study the in vivo effects of a variety of therapeutic approaches. However, it remains unclear whether these xenograft models entirely reflect clinical presentations of KSHV(+ PEL, especially given the recent description of extracavitary solid tumor variants arising in patients. In addition, effusion and solid tumor cells propagated in vivo exhibit unique biology, differing from one another or from their parental cell lines propagated through in vitro culture. Therefore, we used a KSHV(+ PEL/BCBL-1 xenograft model involving non-obese diabetic/severe-combined immunodeficient (NOD/SCID mice, and compared characteristics of effusion and solid tumors with their parent cell culture-derived counterparts. Our results indicate that although this xenograft model can be used for study of effusion and solid lymphoma observed in patients, tumor cells in vivo display unique features to those passed in vitro, including viral lytic gene expression profile, rate of solid tumor development, the host proteins and the complex of tumor microenvironment. These items should be carefully considered when the xenograft model is used for testing novel therapeutic strategies against KSHV-related lymphoma.

  18. Escherichia coli BdcA controls biofilm dispersal in Pseudomonas aeruginosa and Rhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Wood Thomas K

    2011-10-01

    Full Text Available Abstract Background Previously we showed that BdcA controls Escherichia coli biofilm dispersal by binding the ubiquitous bacterial signal cyclic diguanylate (c-di-GMP; upon reducing the concentration of c-di-GMP, the cell shifts to the planktonic state by increasing motility, decreasing aggregation, and decreasing production of biofilm adhesins. Findings Here we report that BdcA also increases biofilm dispersal in other Gram-negative bacteria including Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhizobium meliloti. BdcA binds c-di-GMP in these strains and thereby reduces the effective c-di-GMP concentrations as demonstrated by increases in swimming motility and swarming motility as well as by a reduction in extracellular polysaccharide production. We also develop a method to displace existing biofilms by adding BdcA via conjugation from E. coli in mixed-species biofilms. Conclusion Since BdcA shows the ability to control biofilm dispersal in diverse bacteria, BdcA has the potential to be used as a tool to disperse biofilms for engineering and medical applications.

  19. Anthranilate deteriorates the structure of Pseudomonas aeruginosa biofilms and antagonizes the biofilm-enhancing indole effect.

    Science.gov (United States)

    Kim, Soo-Kyoung; Park, Ha-Young; Lee, Joon-Hee

    2015-04-01

    Anthranilate and indole are alternative degradation products of tryptophan, depending on the bacterial species. While indole enhances the biofilm formation of Pseudomonas aeruginosa, we found that anthranilate, the tryptophan degradation product of P. aeruginosa, had an opposite effect on P. aeruginosa biofilm formation, in which anthranilate deteriorated the mushroom structure of biofilm. The anthranilate effect on biofilm formation was differentially exerted depending on the developmental stage and the presence of shear force. Anthranilate slightly accelerated the initial attachment of P. aeruginosa at the early stage of biofilm development and appeared to build more biofilm without shear force. But anthranilate weakened the biofilm structure in the late stage, deteriorating the mushroom structure of biofilms with shear force to make a flat biofilm. To investigate the interplay of anthranilate with indole in biofilm formation, biofilms were cotreated with anthranilate and indole, and the results showed that anthranilate antagonized the biofilm-enhancing effect of indole. Anthranilate was able to deteriorate the preformed biofilm. The effect of anthranilate and indole on biofilm formation was quorum sensing independent. AntR, a regulator of anthranilate-degrading metabolism was synergistically activated by cotreatment with anthranilate and indole, suggesting that indole might enhance biofilm formation by facilitating the degradation of anthranilate. Anthranilate slightly but significantly affected the cyclic diguaniylate (c-di-GMP) level and transcription of major extracellular polysaccharide (Psl, Pel, and alginate) operons. These results suggest that anthranilate may be a promising antibiofilm agent and antagonize the effect of indole on P. aeruginosa biofilm formation.

  20. vPELS: An E-Learning Social Environment for VLSI Design with Content Security Using DRM

    Science.gov (United States)

    Dewan, Jahangir; Chowdhury, Morshed; Batten, Lynn

    2014-01-01

    This article provides a proposal for personal e-learning system (vPELS [where "v" stands for VLSI: very large scale integrated circuit])) architecture in the context of social network environment for VLSI Design. The main objective of vPELS is to develop individual skills on a specific subject--say, VLSI--and share resources with peers.…

  1. Polysaccharides serve as scaffold of biofilms formed by mucoid Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Yang, Liang; Hengzhuang, Wang; Wu, Hong

    2012-01-01

    Chronic lung infection by mucoid Pseudomonas aeruginosa is one of the major pathologic features in patients with cystic fibrosis. Mucoid P. aeruginosa is notorious for its biofilm forming capability and resistance to immune attacks. In this study, the roles of extracellular polymeric substances...... from biofilms formed by mucoid P. aeruginosa were investigated. Alginate is not an essential structure component for mucoid P. aeruginosa biofilms. Genetic studies revealed that Pel and Psl polysaccharides serve as essential scaffold and mediate macrocolony formation in mucoid P. aeruginosa biofilms...

  2. Deposición de películas de AlN como dispositivos semiconductores

    Directory of Open Access Journals (Sweden)

    Julio Cesar Caicedo

    2012-10-01

    Full Text Available Películas de AlN fueron depositados por la técnica de deposición por láser pulsado (PLD, utilizando un láser Nd: YAG con una longitud de onda de 1064 nm. Las películas fueron depositadas en una atmósfera de nitrógeno como gas de trabajo; como cátodo se usó aluminio de alta pureza (99,99%. Las películas fueron depositadas con una fluencia del láser de 2,28 J/cm2 durante 10 minutos sobre sustratos de silicio (100. La presión de trabajo fue de 9 x 10-3 mbar y la temperatura del sustrato se varió desde 200 °C a 630 °C. El espesor medido por perfilometría fue de 150 nm para todas las películas. Además se fabricaron los dispositivos de ondas acústicas de superficie (SAW con una configuración Mo/AlN/Si, empleando AlN-bufer y un canal de Mo. La morfología y la composición de las películas se estudiaron mediante microscopía electrónica de barrido (MEB y energía dispersiva de rayos X de análisis (EDX, respectivamente. Los espectros de reflectancia óptica y color de coordenadas de las películas se obtuvieron por la técnica óptica reflectometría espectral en el rango de 400-900 cm-1 por medio de un espectrofotómetro Ocean Optics 2000. En este trabajo se encontró una clara dependencia de las propiedades morfológicas, reflectancia, pureza dominante, longitud de onda del color, la respuesta de frecuencia y velocidad de la onda acústica en términos de la temperatura aplicada al sustrato. Se observó una reducción en la reflectancia de aproximadamente 30% y aumento de velocidad de la onda acústica de aproximadamente 1,3% cuando la temperatura se incrementó desde 200 °C a 630 °C.

  3. Películas delgadas de CNx formadas por PLD a diferentes temperaturas

    Directory of Open Access Journals (Sweden)

    Jorge Luis Gallego Cano

    2011-01-01

    Full Text Available Películas delgadas de nitruro de carbono (CNx fueron formadas por la técnica de depósito por láser pulsado (PLD, siglas en inglés. Para la ablación incidió sobre la superficie del blanco de grafito pirolítico (99.999% de pureza un láser Nd:YAG (1064 nm, 500 mJ, cuya fluencia del haz se mantuvo a un valor de 10 J¿cm-2. Las películas se formaron sobre sustratos de Si (100 y en una atmósfera de nitrógeno, y a tres valores diferentes de temperatura del sustrato (21, 50 y 200° C. Durante el crecimiento de estas películas se mantuvo la presión del gas ambiente constante (2,66 Pa. También se analizaron las propiedades mecánicas y químicas de las películas mediante microscopia de fuerza atómica (AFM, por sus siglas en inglés, espectroscopia infrarroja (FTIR, energía dispersiva de rayos X (EDX y nanoindentación. El análisis de FTIR revela la presencia de modos activos alrededor de 1108 cm-1, 1465 cm-1, 2270 cm-1, asociados a enlaces simples, dobles y triples de CN, respectivamente. Por medio de EDX, se estudió la composición química de las muestras, encontrándose bajos contenidos de nitrógeno, con una variación entre el 3 y 6 %at. Las propiedades mecánicas fueron evaluadas mediante la técnica de nanoindentación. La mayor dureza de las muestras fue de 14 GPa, obtenida para la muestra formada a una temperatura del sustrato de 200º C.

  4. Emissivity Measurements and Laboratory Intercalibration at PSF of Oxford University and PEL of DLR

    Science.gov (United States)

    Maturilli, A.; Bowles, N. E.; Thomas, I. R.; Helbert, J.

    2013-09-01

    Emissivity spectra of analogue materials are needed for the analysis of remote sensing emission spectra of airless surfaces. The increasing number of planetary missions to the Moon, Mercury, asteroids, and other minor bodies require appropriate laboratory set-ups to fulfill those requirements. Two independent groups, one at Oxford University and the other at the German Aerospace Center (DLR) in Berlin provide suitable chambers for emissivity measurements in vacuum. The Planetary Spectroscopy Facility (PSF) of the Oxford University favored a high vacuum, low to average sample temperatures, and a limited spectral range for measurements, mostly inspired from lunar and asteroids environment. At the Planetary Emissivity Laboratory (PEL) of DLR, the set-up allows measuring in low-moderate vacuum, for sample temperatures from low to very high (> 1000 K) and in an extended spectral range (1 to over 100μm), with Mercury being the principal driver of chamber design. To understand the influence of environment parameters on emissivity spectra, we measured a fine (0-25 μm) sample of volcanic dust from Iceland (PEL ID 00000240) under several environmental conditions at PSF, and for comparison under standard conditions at PEL.

  5. La restauración digital de películas

    Directory of Open Access Journals (Sweden)

    Catanese, Rossella

    2014-12-01

    Full Text Available Este artículo trata sobre la conservación y la restauración de películas con tecnologías digitales. Las películas, como expresión de la memoria colectiva, forman parte del patrimonio común de la humanidad, y merecen ser preservadas y difundidas. Por eso, la cuestión de la preservación de los materiales cinematográficos está ganando peso, sobre todo si tenemos en cuenta la fragilidad estructural y la corta duración del stock de películas. El estado actual del medio audiovisual es de transición: poco a poco el elemento analógico y fotoquímico es sustituido por el sistema digital. Lo cual influye mucho en las prácticas de producción y distribución del cine, y también en los debates teóricos sobre el medio: los criterios de archivo y los procesos de restauración no son una excepción a esta lógica.Aquest article tracta sobre la conservació i la restauració de pel·lícules amb tecnologies digitals. Les pel·lícules, com a expressió de la memòria col·lectiva, formen part del patrimoni comú de la humanitat, i mereixen ser preservades i difoses. Per això, la qüestió de la preservació dels materials cinematogràfics està guanyant pes, sobretot si tenim en compte la fragilitat estructural i la curta durada de l'estoc de pel·lícules. L'estat actual del mitjà audiovisual és de transició: a poc a poc l'element analògic i fotoquímic és substituït pel sistema digital. I això influeix molt en les pràctiques de producció i distribució del cinema, i també en els debats teòrics sobre el mitjà: els criteris d'arxivament i els processos de restauració no són una excepció a aquesta lògica.This article focuses on the issues of conservation and restoration of films through digital technologies. Films, as an expression of collective memory, become part of the common heritage of humankind, which deserves to be safeguarded and disseminated. As a consequence of this awareness, the issue of preserving cinematic

  6. La restauració digital de pel·lícules

    Directory of Open Access Journals (Sweden)

    Catanese, Rossella

    2014-12-01

    Full Text Available Aquest article tracta sobre la conservació i la restauració de pel·lícules amb tecnologies digitals. Les pel·lícules, com a expressió de la memòria col·lectiva, formen part del patrimoni comú de la humanitat, i mereixen ser preservades i difoses. Per això, la qüestió de la preservació dels materials cinematogràfics està guanyant pes, sobretot si tenim en compte la fragilitat estructural i la curta durada de l'estoc de pel·lícules. L'estat actual del mitjà audiovisual és de transició: a poc a poc l'element analògic i fotoquímic és substituït pel sistema digital. I això influeix molt en les pràctiques de producció i distribució del cinema, i també en els debats teòrics sobre el mitjà: els criteris d'arxivament i els processos de restauració no són una excepció a aquesta lògica.Este artículo trata sobre la conservación y la restauración de películas con tecnologías digitales. Las películas, como expresión de la memoria colectiva, forman parte del patrimonio común de la humanidad, y merecen ser preservadas y difundidas. Por eso, la cuestión de la preservación de los materiales cinematográficos está ganando peso, sobre todo si tenemos en cuenta la fragilidad estructural y la corta duración del stock de películas. El estado actual del medio audiovisual es de transición: poco a poco el elemento analógico y fotoquímico es sustituido por el sistema digital. Lo cual influye mucho en las prácticas de producción y distribución del cine, y también en los debates teóricos sobre el medio: los criterios de archivo y los procesos de restauración no son una excepción a esta lógica.This article focuses on the issues of conservation and restoration of films through digital technologies. Films, as an expression of collective memory, become part of the common heritage of humankind, which deserves to be safeguarded and disseminated. As a consequence of this awareness, the issue of preserving cinematic

  7. Evaluation of the effect of c-di-GMP on acidogenicity and aciduricity of Streptococcus mutans%外源性C-di-GMP对变形链球菌产酸、耐酸能力的影响

    Institute of Scientific and Technical Information of China (English)

    闫文娟; 吴补领; 屈铁军; 高杰; 赵红萍; 苏凌云; 余擎

    2009-01-01

    目的:初步探讨外源性c-di-GMP对变形链球菌产酸、耐酸能力的影响.方法:外源性c-di-GMP与生理盐水分别加入至含变形链球菌UA159菌液的BHI培养基中,比较两组对变形链球菌产酸、耐酸能力的影响.结果:c-di-GMP处理组与生理盐水组相比,产酸、耐酸能力明显下降,差异有统计学意义,经t检验,P<0.05.结论:c-di-GMP可以抑制变形链球菌的产酸、耐酸能力,可以单独也可以与其它的抗龋制剂联合应用控制龋病.

  8. Implementació d'una Intranet pel Restaurant "Cal Fesu"

    OpenAIRE

    Maldonado Rubio, Lluís Manel

    2007-01-01

    Aquest projecte consisteix en el disseny i implementació d'una intranet amb zona privada pel restaurant "Cal Fesu", utilitzant una tecnologia puntera com és J2EE (struts). Este proyecto consiste en el diseño e implementación de una intranet con zona privada para el restaurante "Cal Fesu", utilizando una tecnología puntera como es J2EE (struts). This project consists of design and implementation of an intranet with a private area for the restaurant "Cal Fesu", using a leading technology ...

  9. Desarrollo de microrreactores basados en películas y nanopartículas de zeolita

    OpenAIRE

    Pérez, Claudio Nicolás

    2015-01-01

    Las estructuras catalíticas constituidas por canales de dimensiones menores a 500 micrómetros se denominan microrreactores, y se han comenzado a estudiar en los últimos años debido a las ventajas que presentan respecto de los catalizadores estructurados convencionales. Dicha miniaturización puede generar mejoras en el rendimiento de procesos catalíticos, pero al mismo tiempo aumenta la dificultad en la deposición y adherencia de las fases activas en forma de películas en las paredes interiore...

  10. Ripstein, un olvido innecesario : debate sobre las 100 películas iberoamericanas

    OpenAIRE

    Gordillo Álvarez, Inmaculada

    2009-01-01

    El artículo titulado “Las olvidadas entre las mejores películas iberoamericanas”, autoría de Alfredo Caminos y Fernando A. Saad, que se publicara en Guión Actualidad el pasado 16 de febrero, ha motivado que profesores y académicos, de diversas universidades españolas y latinoamericanas, decidieran rescatar filmes perdidos en la memoria y también recordar a directores alejados de los espectadores. A continuación, una de las reflexiones.

  11. Programa de computador para el cálculo del espesor y de las constantes ópticas de películas delgadas semiconductoras

    OpenAIRE

    G. Gordillo; Rodríguez, J.A. (José); Cardona,R.; Infante, P.

    2012-01-01

    Utilizando un sencillo modelo físico propuesto por Swanepoel en 1983 sobre la transmisión de la luz en películas delgadas se escribió un programa de computador para el cálculo del espesor y de las constantes ópticas de películas delgadas. El programa fue aplicado al análisis de la transmisión en películas delgadas de CdS.

  12. Preparación de películas para alimentos a partir de concentrados proteicos de haba (vicia faba

    Directory of Open Access Journals (Sweden)

    Ana Patricia Rozo

    2010-10-01

    Full Text Available El trabajo se planeó con el objeto de evaluar la factibilidad de utilizar concentrados proteicos de haba en la preparación de películas para recubrir alimentos, utilizando como patrón de comparación películas preparadas con albúmina fresca de huevo. Los resultados muestran que utilizando concentrados proteicos de haba sin deshidratar, en suspensiones que contengan 5 g de proteína por 100 g de agua, y adicionando glicerol como agente plastificante, se pueden obtener películas cuyas características de permeabilidad al vapor de agua, solubilidad y contenido de agua dependen de las condiciones de secado del material.

  13. Why Were Polysaccharides Necessary?

    Science.gov (United States)

    Tolstoguzov, Vladimir

    2004-12-01

    The main idea of this paper is that the primordial soup may be modelled by food systems whose structure-property relationship is based on non-specific interactions between denatured biopolymers. According to the proposed hypothesis, polysaccharides were the first biopolymers that decreased concentration of salts in the primordial soup, `compatibilised' and drove the joint evolution of proto-biopolymers. Synthesis of macromolecules within the polysaccharide-rich medium could have resulted in phase separation of the primordial soup and concentration of the polypeptides and nucleic acids in the dispersed phase particles. The concentration of proto-biopolymer mixtures favoured their cross-linking in hybrid supermacromolecules of conjugates. The cross-linking of proto-biopolymers could occur by hydrophobic, electrostatic interactions, H-bonds due to freezing aqueous mixed biopolymer dispersions and/or by covalent bonds due to the Maillard reaction. Cross-linking could have increased the local concentration of chemically different proto-biopolymers, fixed their relative positions and made their interactions reproducible. Attractive-repulsive interactions between cross-linked proto-biopolymer chains could develop pairing of the monomer units, improved chemical stability (against hydrolysis) and led to their mutual catalytic activity and coding. Conjugates could probably evolve to the first self-reproduced entities and then to specialized cellular organelles. Phase separation of the primordial soup with concentration of conjugates in the dispersed particles has probably resulted in proto-cells.

  14. Polysaccharides: Molecular and Supramolecular Structures. Terminology.

    NARCIS (Netherlands)

    Heinze, Thomas; Petzold-Welcke, Katrin; Dam, van J.E.G.

    2012-01-01

    This chapter summarises important issues
    about the molecular and supramolecular structure
    of polysaccharides. It describes the terminology
    of polysaccharides systematically. The
    polysaccharides are divided regarding the
    molecular structures in glucans, polyoses,
    polysaccharid

  15. Modelación de las propiedades mecánicas de películas de quitosana

    OpenAIRE

    Casariego, A.; Díaz,R; Sergrañes, Y.; Nieto, O.M.; Durán, C.; López, N.; M. Rodríguez; González, J.

    2009-01-01

    Se elaboraron películas a partir de disoluciones a 3 % (m/v) de quitosana en ácido láctico a 1% (v/v), empleando glicerina, sorbitol o polietilenglicol como plastificante en concentraciones de 0,25 a 0,50 mL/g de quitosana. Se midieron el esfuerzo tensil, elongación, fuerza de ruptura, deformación y el espesor de las películas, con el objetivo de evaluar la influencia de la masa molar y concentración de plastificante sobre sus propiedades mecánicas. Se obtuvieron los m...

  16. Informe final. Asesoría integral para la toma de decisiones en pesca y acuicultura 2010. Actividad 1: recursos pelágicos pesquerías pelágicas centro sur, 2010.

    OpenAIRE

    Aranis Rodríguez, Antonio; Caballero González, Leonardo; Gómez Aguilera, Alejandra; Ramírez E., M.; Eisele M., G.; González Gómez, M.; Cerna Troncoso, Francisco; Bocic Wulf, Víctor; López Ahumada, Amalia; Machuca Rodríguez, Cecilia; Espíndola Rebolledo, Fernando; Vera Elizondo, Carlos; Young Ugalde, Zaida

    2011-01-01

    El estudio tiene como objetivo la recolección, validación y análisis integrado de la información biológica y pesquera de los recursos pelágicos y la actividad extractiva realizada en la zona centro sur durante el año 2010.

  17. Informe final. Asesoría integral para la toma de deciones en pesca y acuicultura 2010. Actividad 1: recursos pelágicos pesquerías pelágicas centro sur, 2010 SUBPESCA.

    OpenAIRE

    Aranis Rodríguez, Antonio; Caballero González, Leonardo; Gómez Aguilera, Alejandra; Ramírez E., M.; Eisele M., G.; González Gómez, M.; Cerna Troncoso, Francisco; Bocic Wulf, Víctor; López Ahumada, Amalia; Machuca Rodríguez, Cecilia; Espíndola Rebolledo, Fernando; Vera Elizondo, Carlos; Young Ugalde, Zaida

    2013-01-01

    El estudio tiene como objetivo la recolección, validación y análisis integrado de la información biológica y pesquera de los recursos pelágicos y la actividad extractiva realizada en la zona centro sur durante el año 2010.

  18. Las elecciones ocupacionales en la película “El hijo de la novia”

    OpenAIRE

    Rodríguez Bailón, M

    2006-01-01

    Resumen: El cine puede ser un instrumento de análisis y reflexión acerca de la ocupación humana y de los aspectos que hacen emergerla y mantenerla.Objetivo y método: Análisis descriptivo-interpretativo del rol ocupacional del protagonista de la película “El hijo de la Novia” desde la visión fenomenológica del Modelo de Ocupación Humana.Conclusiones: “El hijo de la novia” demuestra la elección de roles ocupacionales motivados por los valores propios de la persona, sus intereses y su sentido de...

  19. Transport properties of pyroclastic rocks from Montagne Pelée volcano (Martinique, Lesser Antilles)

    Science.gov (United States)

    Bernard, Marie-Lise; Zamora, Maria; GéRaud, Yves; Boudon, Georges

    2007-05-01

    The hydraulic and electrical properties of pyroclastic rocks have been investigated in laboratory on a representative sampling of Montagne Pelée (Martinique, France) deposits with renewed interest in geophysical applications. This sampling covers all the lithologic units of this volcano: lava dome and lava flows, pumices from ash-and-pumice fall and flow deposits, lava blocks from block-and-ash flow and Peléean "nuées ardentes" deposits, scoriae from scoria flow deposits. The connected porosity varies over a wide range from 3 to 62%. The unconnected porosity is important only on pumices where it can reach 15%. The permeability covers more than 5 orders of magnitude, ranging from 10-16 to 35 × 10-12 m2. The higher values are obtained on lava blocks and the scoriae, even if these rocks are less porous than the pumices. The formation factor ranges from 7 to 1139. The transport properties of these rocks are slightly correlated with porosity. This indicates that these properties are not only controlled by the connected porosity. To connect the transport properties to the textural characteristics of the pore network of pyroclastic rocks, different models, based on geometrical considerations or percolation theory, were tested. The pore access radius distribution and the tortuosity control the transport properties of pyroclastic rocks. Consequently, the models (electric and hydraulic) based on the concept of percolation (e.g., the models of Katz and Thompson), apply better than the equivalent channel model of Kozeny-Carman. In addition, the difference in transport properties observed on lava blocks and pumices confirms that the mechanisms of degassing and vesiculation are different for these two types of rock.

  20. Computer simulation and experimental study of the polysaccharide-polysaccharide interaction in the bacteria Azospirillum brasilense Sp245

    Science.gov (United States)

    Arefeva, Oksana A.; Kuznetsov, Pavel E.; Tolmachev, Sergey A.; Kupadze, Machammad S.; Khlebtsov, Boris N.; Rogacheva, Svetlana M.

    2003-09-01

    We have studied the conformational properties and molecular dynamics of polysaccharides by using molecular modeling methods. Theoretical and experimental results of polysaccharide-polysaccharide interactions are described.

  1. Estudio antimicrobiano de películas de quitosano-alcohol polivinílico dopadas con TiO2

    OpenAIRE

    2007-01-01

    Se ha preparado películas de alcohol polivinílico (PVA), quitosano-PVA y quitosano-PVA dopadas con TiO2 y evaluado sus propiedades antimicrobianas frente a cepas bacterianas de S. aureus, E. coli y P. aeruginosa. Se encontró que estas películas no tienen actividad frente a estos microorganismos, pero si actúan como una barrera eficaz. Por estas propiedades tienen una potencial aplicación como películas protectoras de piel de quemados y como material para envasado de alimentos. Films of Pol...

  2. Preparación y caracterización de películas de alcohol polivinílico embebidas con extracto de sangre de grado

    OpenAIRE

    2007-01-01

    Se han preparado películas de quitosano-alcohol polivinílico conteniendo extractos hidroalcóholico, alcóholico y acuoso de sangre de grado (Croton lechleri), y se evaluaron sus propiedades antimicrobianas frente a cepas bacterianas de S. aureus, E. coli y P. aeruginosa. Se encontró que estas películas, al igual que el látex, tienen actividad sólo frente a S. aureus. Estas películas tienen potencial aplicación en el tratamiento de heridas. Chitosan-polyvinyl(alcohol) films containing dragon...

  3. Las elecciones ocupacionales en la película “El hijo de la novia”

    Directory of Open Access Journals (Sweden)

    Rodríguez Bailón, M

    2006-02-01

    Full Text Available Resumen: El cine puede ser un instrumento de análisis y reflexión acerca de la ocupación humana y de los aspectos que hacen emergerla y mantenerla.Objetivo y método: Análisis descriptivo-interpretativo del rol ocupacional del protagonista de la película “El hijo de la Novia” desde la visión fenomenológica del Modelo de Ocupación Humana.Conclusiones: “El hijo de la novia” demuestra la elección de roles ocupacionales motivados por los valores propios de la persona, sus intereses y su sentido de eficacia e influenciados por el ambiente.AbstractCinema may be a good tool for the analysis and reflection about human occupation and the aspects which make its emergency and maintenance.Objective and Method: Descriptive-interpretative analysis of the occupational roles of the film characters in "Son of the bride" from the phenomenologic viewpoint of Model of Human Occupation.Conclusions: The film of "Son of the bride" shows the choice of occupational roles run by the individual's values, and their interests, and efficiency influenced by environment.

  4. Alginato de sodio en el desarrollo de películas comestibles

    Directory of Open Access Journals (Sweden)

    Daniel Alexander Méndez Reyes

    2014-12-01

    Full Text Available Alginato, es un término que se refiere a un grupo de polisacáridos presentes en las algas pardas, los cuales cuentan con una importancia especial para diferentes industrias (alimentaria, textil, farmacéutica, cosmética, entre otras, atribuida a su capacidad para formar geles fuertes en presencia de cationes calcio (Ca+2. El alginato de sodio es la forma más comercializada de alginato y sus aplicaciones en la industria alimentaria hoy en día están generando avances en el desarrollo de nuevos e innovadores biomateriales con características únicas, tales como, propiedades de barrera contra la pérdida de humedad causada por la deshidratación en alimentos de alto contenido de humedad, soporte para el transporte de compuestos antimicrobianos y probioticos entre otros, para mantener la calidad de productos alimentarios en almacenamiento. En este trabajo se recopiló información referente a la incidencia de diferentes polímeros, biocompuestos, aditivos y del proceso de gelificación en la producción de películas comestibles destinadas a la ingeniería del empaque.

  5. La inocencia cuestionada. Representaciones sociales, valores y jerarquías en películas animadas infantiles

    Directory of Open Access Journals (Sweden)

    Alejandra Martínez

    2013-04-01

    Full Text Available En este escrito presentamos los principales resultados de un trabajo de investigación realizado entre 2010 y 2012, que tuvo como uno de sus objetivos centrales analizar las representaciones de las condiciones objetivas de existencia asignadas a personajes de películas animadas infantiles. Se trabajó con tres producciones de gran consumo en el mercado mundial. El análisis realizado nos permite señalar que, a pesar de los cambios sociales que se produjeron a lo largo de casi 40 años, las películas infantiles tienden a recuperar modos de representación históricamente legitimadas, que coadyuvan a la reproducción de sentidos y jerarquías dominantes.

  6. Estudio del efecto de una película antimicrobiana en la vida útil del queso Costeño

    Directory of Open Access Journals (Sweden)

    Margarita Rosa Arteaga Márquez

    2015-09-01

    Full Text Available Se estudió el efecto de una película antimicrobiana en la vida útil del queso Costeño elaborado a diferentes concentraciones de cloruro de sodio (2,5 % p/p sin cubrimiento de película; 2,5 y 3,0 % p/p cubierto con película antimicrobiana, almacenado (0, 5, 10, 15, 20, 25 y 30 días a temperaturas de 12 ± 1 ºC y 28 ± 2 ºC. El principio activo fue nisina (16 mg/100 mL de solución. Se realizaron análisis químicos (pH, acidez titulable, materia grasa y humedad, microbiológicos (recuentos de coliformes, Escherichia coli, Staphylococcus aureus coagulasa positiva, detección de Salmonella y recuento de mohos y levaduras y sensoriales (pruebas de ordenación por atributos y de escala hedónica. Los resultados mostraron que para los quesos almacenados a 12 ± 1 ºC, no hubo diferencias estadísticas significativas en el comportamiento del pH, y para la acidez se encontraron diferencias estadísticas significativas los días 15, 20, 25 y 30. Respecto al contenido de cloruro de sodio se obtuvo mayor pérdida de humedad y aumento en el contenido de materia grasa con diferencias estadísticas significativas los días 30 y 5 para los quesos almacenados a 12 ± 1 ºC y 28 ± 2 ºC, respectivamente. La temperatura a 12 ± 1 ºC fue el factor más influyente en la conservación del queso. Los tratamientos con cubrimiento de película fueron aceptados sensorialmente durante los 30 días de estudio y hubo diferencia respecto al sabor los días 20 al 30. El tratamiento control presentó crecimiento visible de mohos y levaduras el día 15. La película antimicrobiana ejerció un efecto inhibitorio sobre Staphyloccocus aureus coagulasa positiva en los quesos.

  7. Autoridades invisibles y autorizaciones visibles en la película argentina Rompecabezas de Natalia Smirnoff

    Directory of Open Access Journals (Sweden)

    Mullaly, Laurence H.

    2013-06-01

    Full Text Available In the Argentinian cinema of the end of the 90’s and beginning of the 21st century, the representations of femininity and masculinity have become richer thanks to alternative visions, most frequently proposed by female directors. Natalia Smirnoff’s film Rompecabezas (Puzzle is a perfect example. It tells the story of an ordinary woman whose psychosexual awakening shakes up the invisible forces that had dictated her life up to that point. Rompecabezas explores the everlasting effect and influence on the patriarchal structures in constructing identity. The aim of this work, rooted in a gender perspective, is to study in what way both hierarchy and symbolic systems operate and to what extent Natalia Smirnoff provides us with a powerful (revision of transformation for women.En el cine argentino de finales de los años 90 y principios del siglo actual, las representaciones de la feminidad y la masculinidad se están enriqueciendo gracias a las visiones alternativas que nos ofrecen en su mayoría directoras. La película de Natalia Smirnoff, que se centra en la trayectoria de una mujer ordinaria cuyo despertar psicosexual choca con las autoridades invisibles que hasta ahora regían su vida, da testimonio de ello. Rompecabezas (Puzzle explora la permanencia y la influencia de las estructuras patriarcales en la construcción de las identidades. A partir de una perspectiva de género, el presente trabajo pretende analizar de qué manera opera el conjunto de las jerarquías y de los sistemas simbólicos y en qué medida Natalia Smirnoff nos proporciona una (revisión transformadora de las mujeres.

  8. Física de Película: una herramienta docente para la enseñanza de Física universitaria usando fragmentos de películas

    OpenAIRE

    2011-01-01

    Desde su infancia, el alumno se encuentra sometido a todo tipo de estímulos audiovisuales. Por dicho motivo, puede reaccionar favorablemente ante el uso de fragmentos de películas en el aula como recurso docente. Un reciente proyecto universitario de innovación combina ejemplos de cine con explicaciones desarrolladas ad hoc, para mostrar al alumno ejemplos de Física General. Los resultados obtenidos en el último curso muestran una mejora significativa en los resultados académicos de la asigna...

  9. Sucrose release from polysaccharide gels.

    Science.gov (United States)

    Nishinari, Katsuyoshi; Fang, Yapeng

    2016-05-18

    Sucrose release from polysaccharide gels has been studied extensively because it is expected to be useful in understanding flavour release from solid foods and to find a new processing method which produces more palatable and healthier foods. We provide an overview of the release of sucrose and other sugars from gels of agar and related polysaccharides. The addition of sucrose to agar solutions leads to the increase in transparency of the resulting gels and the decrease in syneresis, which is attributed to the decrease in mesh size in gels. The syneresis occurring in the quiescent condition and fluid release induced by compression is discussed. The relationship between the sugar release and the structural, rheological and thermal properties of gels is also discussed. Finally, the future research direction is proposed.

  10. Polysaccharide-Based Micelles for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Nan Zhang

    2013-05-01

    Full Text Available Delivery of hydrophobic molecules and proteins has been an issue due to poor bioavailability following administration. Thus, micelle carrier systems are being investigated to improve drug solubility and stability. Due to problems with toxicity and immunogenicity, natural polysaccharides are being explored as substitutes for synthetic polymers in the development of new micelle systems. By grafting hydrophobic moieties to the polysaccharide backbone, self-assembled micelles can be readily formed in aqueous solution. Many polysaccharides also possess inherent bioactivity that can facilitate mucoadhesion, enhanced targeting of specific tissues, and a reduction in the inflammatory response. Furthermore, the hydrophilic nature of some polysaccharides can be exploited to enhance circulatory stability. This review will highlight the advantages of polysaccharide use in the development of drug delivery systems and will provide an overview of the polysaccharide-based micelles that have been developed to date.

  11. Polysaccharides As Safer Release Systems For Agrochemicals

    OpenAIRE

    Campos E.V.R.; de Oliveira J.L.; Fraceto L.F.; Singh B

    2014-01-01

    International audience; Agrochemicals are used to improve the production of crops. Conventional formulations of agrochemicals can contaminate the environment, in particular in the case of intensive cropping. Hence, there is a need for controlled-release formulations of agrochemicals such as polysaccharides to reduce pollution and health hazards. Natural polysaccharides are hydrophilic, biodegradable polymers. This article reviews the use of polysaccharides in the form of micro- and nanopartic...

  12. Large-scale flank collapse events during the activity of Montagne Pelée, Martinique, Lesser Antilles

    Science.gov (United States)

    Le Friant, Anne; Boudon, Georges; Deplus, Christine; Villemant, Benoã®T.

    2003-01-01

    A horseshoe-shaped structure already identified on the southwestern flank of Montagne Pelée (Martinique, Lesser Antilles arc) was previously interpreted as resulting of a flank collapse event, but no debris avalanche deposits were observed at the time. New offshore high-resolution bathymetry and geophysical data (Aguadomar cruise; December 1998 to January 1999; R/V L'Atalante) lead us to identify three debris avalanche deposits on the submarine western flank of Montagne Pelée extending down to the Grenada Basin. They display morphological fronts and hummocky morphology on bathymetric data, speckled pattern on backscatter data and hyperbolic facies on 3.5 kHz and seismic profiles. New on-land geological studies lead us to identify two other horseshoe-shaped structures on the same flank of the volcano. The three submarine deposits have been traced back to the structures identified on land, which confirms the occurrence of repeated flank collapse events during the evolution of Montagne Pelée. The ages of the last two events are estimated at ˜9 ka and ˜25 ka on the basis of 14C and 238U/230Th dates. Every flank collapse produced debris avalanches which flowed down to the Caribbean Sea. We propose that the repeated instabilities are due to the large asymmetry of the island with western aerial and submarine slopes steeper than the eastern slopes. The asymmetry results from progressive loading by accumulation of volcanic products on the western slopes of the volcano and development of long-term gravitational instabilities. Meteoric and hydrothermal fluid circulation on the floor of the second flank collapse structure also creates a weakened hydrothermalized area, which favors the recurrence of flank collapses.

  13. Retention Behaviors of Uronic Acid-containing Polysaccharides and Neutral Polysaccharides in HPGPC

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The chromatographic behaviors of several uronic acid-containing polysaccharides and neutral polysaccharides were investigated in HPGPC for the first time. The effects of sample concentration and ionic strength of mobile phase on retention time were studied. The mechanism for the effects on Mw determination results of polysaccharides by HPGPC was also discussed.

  14. Desarrollo de una película polimérica con propiedades antiempañantes

    OpenAIRE

    Luis Alejandro Gutiérrez; Sugey Martínez; Cesar Sierra

    2011-01-01

    En la búsqueda de una película poliméricacon óptimas propiedades antiempañantesse seleccionó como matriz polimérica polietilenode baja densidad (LDPE), a lacual se incorporaron por extrusión uno delos siguientes aditivos: polisorbato 80,oleato de sorbitán, monooleato de gliceroly mezcla de glicéridos, cada uno a 3concentraciones. Para evaluar la eficienciaantiempañante de los empaques serealizaron medidas de tensión superficial,ángulos de contacto, medidas de transmisiónde luz y pruebas cuali...

  15. Propiedades ópticas de películas delgadas de a-si:h producidas por evaporacion

    OpenAIRE

    2012-01-01

    Mediciones de transmitancia y reflectancia para películas delgadas de a-Si:H depositadas por evaporación rápida bajo varias condiciones de temperaturas de sustrato Ts y presiones parciales de hidrógeno Ph se llevaron a cabo.EI corrimiento del borde de absorción tanto con Ts y Ph se estudió y correlacionó con el contenido de hidrógeno y los parámetros de deposición.

  16. Grandeza simbólica de la Estatua de la Libertad en la película Ghostbusters II

    OpenAIRE

    2010-01-01

    Toda imagen creada o capturada por el hombre conlleva, necesariamente, un cierto grado de subjetividad y ésta implica, a su vez, ideología que la acompaña. La Estatua de la Libertad que aparece en las distintas películas, en este caso Ghostbusters II, no es la excepción y su aparición aquí, contiene mensajes ideológicos que corresponden con los valores neoliberalista, predominantes en Norteamérica tanto en el momento de su creación, como en la actualidad. La grandeza simbólica de los Estados ...

  17. Efecto del Oxigeno en la Cristalización de Películas Delgadas de GeSbTe

    OpenAIRE

    E. Morales- Sánchez; C. Rivera- Rodríguez; E. Prokhorov; J. González Hernández

    2010-01-01

    En este trabajo se desarrolló un nuevo material para capa activa en Memorias Ópticas Reversibles (MOR), el cual permite grabar información utilizando tres o cuatro niveles de reflectividad en cada punto. Este nuevo material esta basado en Ge1Sb2Te4 dopadas con oxigeno. La técnica de difracción de rayos X muestran que para películas con porcentajes de oxigeno de entre 2 y 8% at. de oxigeno presente en la muestra y cristalizadas a 110° C, la fase cristalina corresponde a la composición estequio...

  18. Advances on Bioactive Polysaccharides from Medicinal Plants.

    Science.gov (United States)

    Xie, Jian-Hua; Jin, Ming-Liang; Morris, Gordon A; Zha, Xue-Qiang; Chen, Han-Qing; Yi, Yang; Li, Jing-En; Wang, Zhi-Jun; Gao, Jie; Nie, Shao-Ping; Shang, Peng; Xie, Ming-Yong

    2016-07-29

    In recent decades, the polysaccharides from the medicinal plants have attracted a lot of attention due to their significant bioactivities, such as anti-tumor activity, antioxidant activity, anticoagulant activity, antidiabetic activity, radioprotection effect, anti-viral activity, hypolipidemic and immunomodulatory activities, which make them suitable for medicinal applications. Previous studies have also shown that medicinal plant polysaccharides are non-toxic and show no side effects. Based on these encouraging observations, most researches have been focusing on the isolation and identification of polysaccharides, as well as their bioactivities. A large number of bioactive polysaccharides with different structural features and biological effects from medicinal plants have been purified and characterized. This review provides a comprehensive summary of the most recent developments in physiochemical, structural features and biological activities of bioactive polysaccharides from a number of important medicinal plants, such as polysaccharides from Astragalus membranaceus, Dendrobium plants, Bupleurum, Cactus fruits, Acanthopanax senticosus, Angelica sinensis (Oliv.) Diels, Aloe barbadensis Miller, and Dimocarpus longan Lour. Moreover, the paper has also been focused on the applications of bioactive polysaccharides for medicinal applications. Recent studies have provided evidence that polysaccharides from medicinal plants can play a vital role in bioactivities. The contents and data will serve as a useful reference material for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents.

  19. Cómo hacer cine hoy en Cuba: prostitución y coproducción en “La película de Ana”

    Directory of Open Access Journals (Sweden)

    Karen Genschow

    2016-03-01

    Full Text Available La película de Ana de Daniel Díaz Torres (2012 trata en primer lugar del jineterismo en Cuba, fenómeno que ha determinado ampliamente el contacto entre extranjeros y cubanos desde la apertura al turismo en masas. En la película esto conlleva una reflexión de las relaciones visuales tanto en términos de género como en términos postcoloniales. Mediante la construcción de una película intradiegética ("la película de Ana" se cuestiona la diferencia entre "autenticidad" y puesta en escena y se sugiere, además, que Cuba entera se ha convertido en una especie de "zona de contacto", donde entran en contacto la lógica capitalista y la nostalgia postsoviética y donde lo "auténticamente" cubano aparece como un espectáculo montado para los extranjeros. Al mismo tiempo la película articula una autorreflexión en el sentido de que estas relaciones de poder se evidencian también en las posibilidades de hacer cine hoy en Cuba, que abarcan esencialmente la coproducción con diferentes países europeos.

  20. Análisis de las películas pasivas generadas en aceros inoxidables implantados con cromo

    Directory of Open Access Journals (Sweden)

    Abreu, C. Mª

    2004-06-01

    Full Text Available This work studies the effect of chromium implantation on the development of passive layers generated electrochemically in alkaline medium over two stainless steels. The XPS analyses show that the layers generated on the implanted steels present less thickness together with similar composition compared to the unimplanted steels layers. However, SEM micrographs show that the layers grown on implanted steels present more defects and less adherence that the films on unimplanted steels. These changes together with the results obtained by Cyclic Voltammetry suggest an oxide structure modification, lattice structure or cristalinity state.

    En este trabajo se estudia el efecto de la implantación de cromo en el desarrollo de capas pasivas generadas electroquímicamente en medio básico sobre dos aceros inoxidables (AISI 430 y AISI 304L. Los análisis de XPS muestran que las películas desarrolladas sobre ambos aceros implantados presentan espesores menores, junto con composiciones similares, a las formadas sobre los no implantados. Sin embargo, en los resultados del examen con MEB se puede apreciar que las películas tienen más defectos (agrietamientos y peor adherencia (especialmente en el AISI 430. Este cambio, junto con los datos de voltametría cíclica, parece sugerir una modificación en la estructura de los óxidos, bien en su grado de cristalinidad o bien en la estructura de su red cristalina.

  1. La imagen turística de Barcelona a través de las películas internacionales

    Directory of Open Access Journals (Sweden)

    Eugeni Osácar Marzal

    2016-01-01

    Full Text Available El mundo audiovisual y, como consecuencia, las imágenes, constituyen un elemento clave del desarrollo social, cultural y económico de las sociedades del siglo XXI. Los espacios reales transformados en localizaciones audiovisuales producen una influencia, consciente o inconsciente, que induce a incorporar al imaginario personal de cada uno los lugares donde se desarrollan sus producciones preferidas. El objetivo principal de esta investigación es analizar la vinculación entre la imagen emitida por las películas de producción o coproducción internacional rodadas total o parcialmente en Barcelona y la imagen turística del destino Barcelona. Los resultados se han obtenido a partir de una metodologia fundamentalmente analíticodescriptiva. Como principal conclusión del estudio se puede remarcar la imagen positiva de Barcelona que transmiten mayoritariamente las películas internacionales y que, además, coincide con los principales atributos y valores del posicionamiento de la ciudad.

  2. Cine y viaje: las películas amateurs murcianas de los años cincuenta

    Directory of Open Access Journals (Sweden)

    Juan Francisco Cerón Gómez

    2001-01-01

    Full Text Available El cine y los viajes han caminado juntos desde la misma aparición del ingenio de los hermanos Lumière. Desde el primer momento, sus operadores fueron enviados por todo el mundo para satisfacer la curiosidad del público de conocer nuevas gentes y lugares. En Murcia, donde se desarrolló un interesante movimiento de cine amateur entre los años cincuenta y ochenta, las llamadas películas de viajes fueron una práctica bastante extendida. En los años cincuenta, momento en el que se detiene este artículo, las hubo de realizadores como Ángel García, Antonio Medina Bardón o Pedro Sanz. Del mismo modo, las películas documentales rodadas en Murcia sirvieron para dar a conocer la imagen de la región en el exterior, aunque casi siempre transmitiendo una idea muy cercana al tópico.

  3. Secular variation study from non-welded pyroclastic deposits from Montagne Pelée volcano, Martinique (West Indies)

    Science.gov (United States)

    Genevey, A.; Gallet, Y.; Boudon, G.

    2002-07-01

    We present palaeomagnetic data obtained from large clasts collected in non-welded pyroclastic deposits from Montagne Pelée volcano (Martinique Island, West Indies). These deposits, dated by the 14C method from 5000 yr BP to the present, comprise block- and ash-flows, ash- and pumice-flows and pumice fallouts. Alternating fields treatment was as a routine chosen to demagnetise large samples for which the magnetisation was measured with a specially designed inductometer. The mean directions obtained from block- and ash-flow deposits of the 1902 and 1929 eruptions are in good agreement with the expected geomagnetic directions at these times in Martinique. The so-called P1 eruption (˜1345 AD), which is characterised by a rarely observed transition from a Peléean to a Plinian eruptive style, allows a direct comparison of the palaeomagnetic directions obtained from the three types of pyroclastic deposits. All deposits provide identical mean directions, which further demonstrates the suitability of the non-welded pyroclastic deposits for geomagnetic secular variation study with a very good accuracy and precision. The possibility of using pyroclastic deposits is promising for obtaining a wider distribution of sampling sites, which may better allow us to constrain our knowledge on the geomagnetic secular variation. We find that large geomagnetic changes occurred in Martinique during the last millennium, while the variations appear more limited prior to this period.

  4. Starch-degrading polysaccharide monooxygenases.

    Science.gov (United States)

    Vu, Van V; Marletta, Michael A

    2016-07-01

    Polysaccharide degradation by hydrolytic enzymes glycoside hydrolases (GHs) is well known. More recently, polysaccharide monooxygenases (PMOs, also known as lytic PMOs or LPMOs) were found to oxidatively degrade various polysaccharides via a copper-dependent hydroxylation. PMOs were previously thought to be either GHs or carbohydrate binding modules (CBMs), and have been re-classified in carbohydrate active enzymes (CAZY) database as auxiliary activity (AA) families. These enzymes include cellulose-active fungal PMOs (AA9, formerly GH61), chitin- and cellulose-active bacterial PMOs (AA10, formerly CBM33), and chitin-active fungal PMOs (AA11). These PMOs significantly boost the activity of GHs under industrially relevant conditions, and thus have great potential in the biomass-based biofuel industry. PMOs that act on starch are the latest PMOs discovered (AA13), which has expanded our perspectives in PMOs studies and starch degradation. Starch-active PMOs have many common structural features and biochemical properties of the PMO superfamily, yet differ from other PMO families in several important aspects. These differences likely correlate, at least in part, to the differences in primary and higher order structures of starch and cellulose, and chitin. In this review we will discuss the discovery, structural features, biochemical and biophysical properties, and possible biological functions of starch-active PMOs, as well as their potential application in the biofuel, food, and other starch-based industries. Important questions regarding various aspects of starch-active PMOs and possible economical driving force for their future studies will also be highlighted.

  5. Thermal studies on natural polysaccharide

    Institute of Scientific and Technical Information of China (English)

    Sunil B Bothara; Sudarshan Singh

    2012-01-01

    Objective: To characterize thermal property of natural gums obtained from the seeds of Diospyros melonoxylon(D. melonoxylon) Roxb, Buchanania lanzan (B. lanzan) spreng and Manilkara zapota (M. zapota) (Linn.) P. Royen syn. Methods: Natural gums were thermally characterized using differential scanning calorimetry (DSC), differential thermal analysis (DTA) and thermo-gravimetric analysis (TGA) under nitrogen atmosphere. Major thermal transitions as well as activation energies of the major decomposition stages were determined. Elemental analysis was performed in order to determine the composition of carbon, hydrogen, nitrogen and sulfur. Results: DSC traces indicated a major intense exothermic transition (around 200℃) followed by weaker exotherm(s). Thermogravimetric analysis showed two phase of weight loss. The first phase has minor weight loss in samples is attributed to the loss of adsorbed and structural water of biopolymers or due to desorption of moisture as hydrogen bound water to the saccharide structure. The second weight loss event may be attributed to the polysaccharide decomposition. The initial decomposition temperature (IDT) was calculated from thermograms obtained of TGA, seed Polysaccharide of D. melonoxylon (IDT 221.21℃), B. lanzan (IPDT 170.4℃) and M. zapota (IPDT 178.6℃) were obtained. According to the integral procedural decomposition temperature (IPDT) values calculated based on the TGA thermograms; D. melonoxylon (IPDT 563.3℃), B. lanzan (IPDT 598.1℃) and M. zapota (IPDT 600.6℃) were obtained respectively. The elemental analysis study shows that the isolated natural Polysaccharides consist of certain percentage of carbon, nitrogen, sulphur and hydrogen in all the gums. Conclusions: The results of the present investigation reveal that the natural gums are thermally stable and these gums can be used as release modifiers in various dosage forms.

  6. Bioactive polysaccharides and gut microbiome (abstract)

    Science.gov (United States)

    Many polysaccharides have shown the ability to reduce plasma cholesterol or postprandial glycemia. Viscosity in the small intestine seems to be required to slow glucose uptake. Cereal mixed linkage beta-glucans, psyllium, glucomannans, and other polysaccharides also seem to require higher molecula...

  7. Pharmacological Action of Adenophora Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    李泱; 李春红; 唐富天; 李新芳

    2004-01-01

    Adenophora polysaccharides (AP), is an active principle extracted from the root of Adenophorae Potaninii Korsh originated in Gansu Province and isolated with boiling water. AP is isolated and purified from the crude drug by DEAE-cellulose and Sephadex G-200 column, with a white powder and mean molecular weight of 8.3×104 , and [α]D20 of AP is + 68. AP is only composed of glucose judging from the analysis of it with patina chromatography (PC) and gas chromatography-mass spectrometer (GC-MS) methods.

  8. Polysaccharides in colon-specific drug delivery.

    Science.gov (United States)

    Sinha, V R; Kumria, R

    2001-08-14

    Natural polysaccharides are now extensively used for the development of solid dosage forms for delivery of drug to the colon. The rationale for the development of a polysaccharide based delivery system for colon is the presence of large amounts of polysaccharidases in the human colon as the colon is inhabited by a large number and variety of bacteria which secrete many enzymes e.g. beta-D-glucosidase, beta-D-galactosidase, amylase, pectinase, xylanase, beta-D-xylosidase, dextranase, etc. Various major approaches utilizing polysaccharides for colon-specific delivery are fermentable coating of the drug core, embedding of the drug in biodegradable matrix, formulation of drug-saccharide conjugate (prodrugs). A large number of polysaccharides have already been studied for their potential as colon-specific drug carrier systems, such as chitosan, pectin, chondroitin sulphate, cyclodextrin, dextrans, guar gum, inulin, amylose and locust bean gum. Recent efforts and approaches exploiting these polysaccharides in colon-specific drug delivery are discussed.

  9. Estrategias para mejorar la funcionalidad y aplicabilidad de películas en base a proteínas de soja

    OpenAIRE

    Ortiz, Cristian Matías

    2015-01-01

    Entre los biopolímeros, las proteínas de soja tienen la capacidad de formar películas comestibles y biodegradables con gran potencial para reemplazar en al menos algunas aplicaciones a los sintéticos derivados del petróleo. Respecto de los polímeros sintéticos, las películas proteicas presentan excelentes propiedades barrera a gases, lípidos y aromas; pero existen aspectos que aún deben ser resueltos para aumentar su difusión y que son foco de investigaciones en la actualidad: i) obtener mate...

  10. Efectos del fenómeno "El Niño 1997-98" sobre los principales recursos pelágicos en la costa peruana

    OpenAIRE

    Miguel Ñiquen; Marilú Bouchon; Sandra Cahuin; José Valdez

    2014-01-01

    En el período abril 1997 setiembre 1998 fueron realizados 5 cruceros de evaluación de los recursos pelágicos en la costa peruana, éstos permitieron observar cambios en la composición por especies, distribución, estructura por tamaño, reproducción y niveles poblacionales de los principales recursos pelágicos. Estos cambios guardan similitud con los observados en los eventos El Niño 1972-73 y 1982-83, especialmente en cuanto a la disminución de la biomasa de anchoveta y el incremento de otras e...

  11. Candida albicans ethanol stimulates Pseudomonas aeruginosa WspR-controlled biofilm formation as part of a cyclic relationship involving phenazines.

    Directory of Open Access Journals (Sweden)

    Annie I Chen

    2014-10-01

    Full Text Available In chronic infections, pathogens are often in the presence of other microbial species. For example, Pseudomonas aeruginosa is a common and detrimental lung pathogen in individuals with cystic fibrosis (CF and co-infections with Candida albicans are common. Here, we show that P. aeruginosa biofilm formation and phenazine production were strongly influenced by ethanol produced by the fungus C. albicans. Ethanol stimulated phenotypes that are indicative of increased levels of cyclic-di-GMP (c-di-GMP, and levels of c-di-GMP were 2-fold higher in the presence of ethanol. Through a genetic screen, we found that the diguanylate cyclase WspR was required for ethanol stimulation of c-di-GMP. Multiple lines of evidence indicate that ethanol stimulates WspR signaling through its cognate sensor WspA, and promotes WspR-dependent activation of Pel exopolysaccharide production, which contributes to biofilm maturation. We also found that ethanol stimulation of WspR promoted P. aeruginosa colonization of CF airway epithelial cells. P. aeruginosa production of phenazines occurs both in the CF lung and in culture, and phenazines enhance ethanol production by C. albicans. Using a C. albicans adh1/adh1 mutant with decreased ethanol production, we found that fungal ethanol strongly altered the spectrum of P. aeruginosa phenazines in favor of those that are most effective against fungi. Thus, a feedback cycle comprised of ethanol and phenazines drives this polymicrobial interaction, and these relationships may provide insight into why co-infection with both P. aeruginosa and C. albicans has been associated with worse outcomes in cystic fibrosis.

  12. An exocellular polysaccharide and its interactions with proteins

    NARCIS (Netherlands)

    Tuinier, R.

    1999-01-01

    In the food industry polysaccharides are used as thickening or gelling agents. Polysaccharides are usually extracted from plants. Micro-organisms are also capable of excreting polysaccharides: exocellular polysaccharides (EPSs). In some cases EPSs are produced in-situ in food products, notably in ac

  13. Repositorio de la Filmoteca de Catalunya: luces y sombras de una película con final feliz

    OpenAIRE

    2015-01-01

    La Filmoteca de Catalunya tiene como misión la recuperación, la conservación, la investigación y la difusión del rico patrimonio cinematográfico. Películas en diversos soportes, pero también fotografías, carteles, fondos personales, etc. En el área de Documentación se gestiona un fondo de medio millón de documentos para acceder y comprender mejor la larga historia del cine catalán y universal. En abril de 2013 se inauguró el repositorio digital de la institución, y a lo largo de los práct...

  14. Docere delectando: series, películas y videojuegos como herramientas de innovación docente

    Directory of Open Access Journals (Sweden)

    Pablo León Cruz

    2015-01-01

    Full Text Available Acercar los contenidos recogidos en las programaciones didácticas al alumnado, destacando la utilidad de los mismos y utilizando ejemplos que resulten de interés es necesario para garantizar un aprendizaje eficaz. Así, el uso de ideas procedentes de series de televisión, películas, libros y videojuegos en los contenidos a desarrollar a lo largo de las sesiones de clase supone una apuesta innovadora en la docencia que podría repercutir en la mejora de la calidad de la enseñanza impartida al lograr la motivación del alumnado en clase y facilitar el aprendizaje utilizando ejemplos cercanos y conocidos.

  15. Numerical simulation of the last flank-collapse event of Montagne Pelée, Martinique, Lesser Antilles

    Science.gov (United States)

    Le Friant, Anne; Heinrich, Philippe; Deplus, Christine; Boudon, Georges

    2003-01-01

    We model the submarine emplacement of a debris avalanche generated by the last flank-collapse event of Montagne Pelée volcano. We estimate the collapsed volume (1.7 km3) using both the volume of the missing material in the horseshoe-shaped structure and the volume of submarine deposits. This avalanche is treated as the gravitational flow of a homogeneous continuum. It is simulated by a finite-difference model, solving mass and momentum conservation equations, that are depth-averaged over the slide thickness. Numerical simulations show that the emplacement of this debris-avalanche can be suitably modeled by a Coulomb-type friction law with a variable friction angle below 10°. We propose that variations of the friction angle are mainly influenced by the thickness of the flowing mass.

  16. Enzymatic production of polysaccharides from gum tragacanth

    DEFF Research Database (Denmark)

    2014-01-01

    Plant polysaccharides, relating to the field of natural probiotic components, can comprise structures similar to human milk oligosaccharides. A method for enzymatic hydrolysis of gum tragacanth from the bush-like legumes of the genus Astragalus, using a combination of pectin hydrolases and a xylo......Plant polysaccharides, relating to the field of natural probiotic components, can comprise structures similar to human milk oligosaccharides. A method for enzymatic hydrolysis of gum tragacanth from the bush-like legumes of the genus Astragalus, using a combination of pectin hydrolases...... and a xylogalacturonan hydrolase, is described. Fractions with different oligo- and/or polysaccharide compositions and structure are separated according to molecular weight....

  17. GEL PERMEATION CHROMATOGRAPHIC ANALYSIS OF LACQUER POLYSACCHARIDE

    Institute of Scientific and Technical Information of China (English)

    QIU Xingping; ZHANG Lina; DU Yumin; QIAN Baogong; LU Zaimin

    1992-01-01

    Ten fractionated samples of Chinese lacquer polysaccharide in aqueous 0.1M NaCl solution were studied by aqueous-phase gel permeation chromatography (GPC). The universal calibration, broad MWD calibration and corrected column dispersion were adopted to the analysis of GPC chromatograms of the polysaccharide. The molecular weights Mw, Mn and polydispersity index Mw/Mn obtained from GPC are in good agreement with the results of light scattering and membrane osmometry. It is verified that the universal calibration concept is applicable to the lacquer polysaccharide having a number of side chains.

  18. A Unique Case of Malignant Pleuropericardial Effusion: HHV-8-Unrelated PEL-Like Lymphoma-A Case Report and Review of the Literature.

    Science.gov (United States)

    Mohammad, Farhan; Siddique, Muhammad Neaman; Siddiqui, Faraz; Popalzai, M; Asgari, Masoud; Odaimi, Marcel

    2014-01-01

    Primary effusion lymphoma (PEL) or body cavity lymphoma is a rare type of extra nodal lymphoma of B-cell origin that presents as lymphomatous effusion(s) without any nodal enlargement or tumor masses. It belongs to the group of AIDS related non-Hodgkin's lymphomas. First described in 1996 in HIV infected individuals who were coinfected with Kaposi's sarcoma-associated herpesvirus (KSHV) or HHV-8 virus, it was included as a separate entity in WHO classification of tumors of hematopoietic and lymphoid tissue in the year 2001. The definition included association with HHV-8 virus as a mandatory diagnostic criterion. However, cases were later reported where PEL-like disease process was diagnosed in HHV-8 negative patients. This was eventually recognized as a rare but distinct entity termed as "HHV-8-unrelated PEL-like lymphoma". Herein, we are reporting a case of an elderly patient who presented with a large pleuropericardial effusion and was eventually diagnosed with this entity. Till date, only around 50 cases of HHV-8-unrelated PEL-like lymphoma have been reported and our case being EBV, HIV, and Hepatitis C negative makes it very unique and rare occurrence. We are also presenting a review of relevant literature focused mainly on comparing outcomes in patients treated with and without chemotherapy.

  19. A Unique Case of Malignant Pleuropericardial Effusion: HHV-8-Unrelated PEL-Like Lymphoma—A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Farhan Mohammad

    2014-01-01

    Full Text Available Primary effusion lymphoma (PEL or body cavity lymphoma is a rare type of extra nodal lymphoma of B-cell origin that presents as lymphomatous effusion(s without any nodal enlargement or tumor masses. It belongs to the group of AIDS related non-Hodgkin’s lymphomas. First described in 1996 in HIV infected individuals who were coinfected with Kaposi’s sarcoma-associated herpesvirus (KSHV or HHV-8 virus, it was included as a separate entity in WHO classification of tumors of hematopoietic and lymphoid tissue in the year 2001. The definition included association with HHV-8 virus as a mandatory diagnostic criterion. However, cases were later reported where PEL-like disease process was diagnosed in HHV-8 negative patients. This was eventually recognized as a rare but distinct entity termed as “HHV-8-unrelated PEL-like lymphoma”. Herein, we are reporting a case of an elderly patient who presented with a large pleuropericardial effusion and was eventually diagnosed with this entity. Till date, only around 50 cases of HHV-8-unrelated PEL-like lymphoma have been reported and our case being EBV, HIV, and Hepatitis C negative makes it very unique and rare occurrence. We are also presenting a review of relevant literature focused mainly on comparing outcomes in patients treated with and without chemotherapy.

  20. Estudio de la conservación de la papaya (Carica papaya L. asociado a la aplicación de películas comestibles

    Directory of Open Access Journals (Sweden)

    Alessandra Almeida Castro

    2011-06-01

    Full Text Available Brasil es un importante productor de papaya, pero sólo una pequeña parte se exporta. Esta fruta es altamente perecedera, por lo que el control de la maduración es esencial para aumentar la vida útil, tanto para el mercado interno como para la exportación. Una alternativa que ha cobrado impulso en el mercado es el uso de películas comestibles biodegradables, entre ellas la película producida a partir de almidón de yuca. En este estudio se evaluó el efecto de una película de almidón de yuca (2 % sobre la papaya almacenadas a temperatura ambiental (25 ± 2 ºC y a 8 °C, y 82 % de humedad relativa durante 6 días de almacenamiento. Se realizaron análisis de pérdida de peso, color, pH, acidez, carotenoides totales, vitamina C y sólidos solubles totales, cada tres días de almacenamiento. La película comestible de almidón de yuca resultó ser una buena alternativa para la preservación de la papaya durante seis días de almacenamiento, en relación a los parámetros pH, grados Brix, acidez y carotenoides.

  1. Estudio de la conservación de la papaya (Carica papaya L. asociado a la aplicación de películas comestibles

    Directory of Open Access Journals (Sweden)

    Alessandra Almeida Castro

    2011-01-01

    Full Text Available Brasil es un importante productor de papaya, pero sólo una pequeña parte se exporta. Esta fruta es altamente perecedera, por lo que el control de la maduración es esencial para aumentar la vida útil, tanto para el mercado interno como para la exportación. Una alternativa que ha cobrado impulso en el mercado es el uso de películas comestibles biodegradables, entre ellas la película producida a partir de almidón de yuca. En este estudio se evaluó el efecto de una película de almidón de yuca (2 % sobre la papaya almacenadas a temperatura ambiental (25 ± 2 ºC y a 8 °C, y 82 % de humedad relativa durante 6 días de almacenamiento. Se realizaron análisis de pérdida de peso, color, pH, acidez, carotenoides totales, vitamina C y sólidos solubles totales, cada tres días de almacenamiento. La película comestible de almidón de yuca resultó ser una buena alternativa para la preservación de la papaya durante seis días de almacenamiento, en relación a los parámetros pH, grados Brix, acidez y carotenoides.

  2. Pharmacological Action of Adenophora Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    李泱; 李春红; 唐富天; 李新芳

    2004-01-01

    @@ Adenophora polysaccharides (AP), is an active principle extracted from the root of Adenophorae Potaninii Korsh originated in Gansu Province and isolated with boiling water(1). AP is isolated and purified from the crude drug by DEAE-cellulose and Sephadex G-200 column, with a white powder and mean molecular weight of 8.3 × 104 , and [α]D20of AP is + 68(1). AP is only composed of glucose judging from the analysis of it with patina chromatography (PC) and gas chromatography-mass spectrometer (GC-MS) methods.The methylation analysis showed that AP is composed of (1→6) linked glucose residues. The measure of nuclear magnetic resonance imaging (NMR) 1H NMR and 14C NMR techniques further proved that AP is α(l→6) linked by Dglucose. The structure of AP is as follows: -[→6]α-D-Glu(1-)n→ (2).

  3. Serogroup quantitation of multivalent polysaccharide and polysaccharide-conjugate meningococcal vaccines from China.

    Science.gov (United States)

    Cook, Matthew C; Gibeault, Sabrina; Filippenko, Vasilisa; Ye, Qiang; Wang, Junzhi; Kunkel, Jeremy P

    2013-07-01

    The active components of most meningococcal vaccines are four antigenic serogroup capsular polysaccharides (A, C, Y, W135). The vaccines, monovalent or multivalent mixtures of either free polysaccharides or polysaccharides conjugated to antigenic carrier proteins, may be in liquid or lyophilised formulations, with or without excipients. Acid hydrolysis and chromatographic methods for serogroup quantitation, which were previously optimised and qualified using polysaccharide-based standards and a narrow range of real vaccines, are here challenged with multiple lots of a broad assortment of additional multivalent polysaccharide-based meningococcal vaccine products. Centrifugal filtration successfully removed all interfering lactose excipient without loss of polysaccharides to allow for the determination of Y and W135 serogroups. Replicate operations by three different analysts indicated high method reproducibility. Results indicated some lot-to-lot and product-to-product variations. However, all vaccines were within general specifications for each serogroup polysaccharide, with the exception of all lots of one polysaccharide vaccine - which by these methods were found to be deficient in the serogroup A component only. These robust techniques are very useful for the evaluation of antigen content and consistency of manufacture. The deformulation, hydrolysis and chromatographic methods may be adaptable for the evaluation of other types of polysaccharide-based vaccines.

  4. Extraction Optimization of Polysaccharides from Pitaya Stems

    Institute of Scientific and Technical Information of China (English)

    HE Cong-fen; LI Peng; ZHAO Hua; SONG Li-ya; ZHU Jun; DONG Yin-mao

    2011-01-01

    [Objective] The aim was to describe the extraction of polysaccharides from pitaya stems.[Method] The hot water,enzyme-assisted and microwave-assisted methods were used,with the microwave-assisted extraction being deemed optimal by general evaluation.[Result] The main factors affecting the yield of polysaccharides in the microwave-assisted extraction,by order of magnitude,were as follows:timemicrowave powertemperature;additionally,optimal conditions included a 10 min extraction time,an 80 ℃ extraction temperature and a microwave setting of 200 W.Using these optimal conditions,the yield of PSPS(Polysaccharides from Pitaya Stems) was 1.42%.After purification,the yield of PSPS was 0.74%.[Conclusion] The PSPS was analyzed by IR,MALDI-TOF-MS and an element analysis technique.It was shown to be a polysaccharide mixture,and the molecular weight was between 3 900 and 4 300 Da.

  5. Electrospinning of polysaccharides for regenerative medicine.

    Science.gov (United States)

    Lee, Kuen Yong; Jeong, Lim; Kang, Yun Ok; Lee, Seung Jin; Park, Won Ho

    2009-10-05

    Electrospinning techniques enable the production of continuous fibers with dimensions on the scale of nanometers from a wide range of natural and synthetic polymers. The number of recent studies regarding electrospun polysaccharides and their derivatives, which are potentially useful for regenerative medicine, is increasing dramatically. However, difficulties regarding the processibility of the polysaccharides (e.g., poor solubility and high surface tension) have limited their application. In this review, we summarize the characteristics of various polysaccharides such as alginate, cellulose, chitin, chitosan, hyaluronic acid, starch, dextran, and heparin, which are either currently being used or have potential to be used for electrospinning. The recent progress of nanofiber matrices electrospun from polysaccharides and their biomedical applications in tissue engineering, wound dressings, drug delivery, and enzyme immobilization are discussed.

  6. Biochemical Aspects of Non-Starch Polysaccharides

    Directory of Open Access Journals (Sweden)

    Rodica Căpriţă

    2010-05-01

    Full Text Available Polysaccharides are macromolecules of monosaccharides linked by glycosidic bonds. Non-starch polysaccharides (NSP are principally non-α-glucan polysaccharides of the plant cell wall. They are a heterogeneous group of polysaccharides with varying degrees of water solubility, size, and structure. The water insoluble fiber fraction include cellulose, galactomannans, xylans, xyloglucans, and lignin, while the water-soluble fibers are the pectins, arabinogalactans, arabinoxylans, and β-(1,3(1,4-D-glucans (β-glucans. Knowledge of the chemical structure of NSP has permitted the development of enzyme technology to overcome their antinutritional effects. The physiological effects of NSP on the digestion and absorption of nutrients in human and monogastric animals have been attributed to their physicochemical properties: hydration properties, viscosity, cation exchange capacity and organic compound absorptive properties. This paper reviews and presents information on NSPs chemistry, physicochemical properties and physiological effects on the nutrient entrapment.

  7. Polysaccharides for the Delivery of Antitumor Drugs

    Directory of Open Access Journals (Sweden)

    Bianca Posocco

    2015-05-01

    Full Text Available Among the several delivery materials available so far, polysaccharides represent very attractive molecules as they can undergo a wide range of chemical modifications, are biocompatible, biodegradable, and have low immunogenic properties. Thus, polysaccharides can contribute to significantly overcome the limitation in the use of many types of drugs, including anti-cancer drugs. The use of conventional anti-cancer drugs is hampered by their high toxicity, mostly depending on the indiscriminate targeting of both cancer and normal cells. Additionally, for nucleic acid based drugs (NABDs, an emerging class of drugs with potential anti-cancer value, the practical use is problematic. This mostly depends on their fast degradation in biological fluids and the difficulties to cross cell membranes. Thus, for both classes of drugs, the development of optimal delivery materials is crucial. Here we discuss the possibility of using different kinds of polysaccharides, such as chitosan, hyaluronic acid, dextran, and pullulan, as smart drug delivery materials. We first describe the main features of polysaccharides, then a general overview about the aspects ruling drug release mechanisms and the pharmacokinetic are reported. Finally, notable examples of polysaccharide-based delivery of conventional anti-cancer drugs and NABDs are reported. Whereas additional research is required, the promising results obtained so far, fully justify further efforts, both in terms of economic support and investigations in the field of polysaccharides as drug delivery materials.

  8. Diagramas de fase CVD para la preparación de películas de iridio

    Directory of Open Access Journals (Sweden)

    Hernández-Pérez, M. A.

    2002-02-01

    Full Text Available Chemical vapor deposition (CVD phase diagrams for the preparation of iridium films were calculated using Gibbs free energy minimization method. Iridium acetylacetonate (Ir(acac3 was used as the precursor compound. Two gaseous mixtures were analyzed: Ir(acac3-O2-Ar and Ir(acac3-Ar. The deposition temperatures were explored from 300 to 800 °C, total pressures from 13.3 to 13.332 Pa and partial pressures of Ir(acac3 gas and O2 gas from 0.001 to 1.000 Pa. The Ir-CVD diagrams predicted that without Oj gas in the gaseous mixture, the solid films consist of two solid phases: Ir+C. In contrast, with addition of O2 to the gaseous mixture, the Ir-CVD diagrams revealed different domains of condensed phases which include IrO2, IrO2+Ir, Ir and Ir+C. These diagrams allow one to establish the total pressures and temperatures required to obtain a given film composition. The results predicted by the Ir-CVD diagrams are in good agreement with those experimentally obtained.

    Se calcularon los diagramas de fase CVD (Chemical Vapor Deposition para la preparación de películas de iridio empleando el método de minimización de la energía libre de Gibbs. Como precursor se utilizó acetilacetonato de iridio (Ir(acac3. Se analizaron las mezclas gaseosas Ir(acac3-O2Ar e Ir(acac3-Ar. Las temperaturas de depósito se exploraron desde 300 hasta 800 °C, las presiones totales de 13,3 a 13.332 Pa y las presiones parciales de los gases Ir(acac3 y O2 desde 0,001 hasta 1.000 Pa. Los diagramas Ir-CVD predicen que sin O2 en la mezcla gaseosa, las películas constan de las fases sólidas Ir+C. En contraste, con adición de O2 los diagramas Ir-CVD revelan diferentes dominios de fases sólidas que incluyen IrO2, IrO2+Ir, Ir e Ir+C. Estos diagramas permiten establecer

  9. Cross-talk between a regulatory small RNA, cyclic-di-GMP signalling and flagellar regulator FlhDC for virulence and bacterial behaviours.

    Science.gov (United States)

    Yuan, Xiaochen; Khokhani, Devanshi; Wu, Xiaogang; Yang, Fenghuan; Biener, Gabriel; Koestler, Benjamin J; Raicu, Valerica; He, Chenyang; Waters, Christopher M; Sundin, George W; Tian, Fang; Yang, Ching-Hong

    2015-11-01

    Dickeya dadantii is a globally dispersed phytopathogen which causes diseases on a wide range of host plants. This pathogen utilizes the type III secretion system (T3SS) to suppress host defense responses, and secretes pectate lyase (Pel) to degrade the plant cell wall. Although the regulatory small RNA (sRNA) RsmB, cyclic diguanylate monophosphate (c-di-GMP) and flagellar regulator have been reported to affect the regulation of these two virulence factors or multiple cell behaviours such as motility and biofilm formation, the linkage between these regulatory components that coordinate the cell behaviours remain unclear. Here, we revealed a sophisticated regulatory network that connects the sRNA, c-di-GMP signalling and flagellar master regulator FlhDC. We propose multi-tiered regulatory mechanisms that link the FlhDC to the T3SS through three distinct pathways including the FlhDC-FliA-YcgR3937 pathway; the FlhDC-EcpC-RpoN-HrpL pathway; and the FlhDC-rsmB-RsmA-HrpL pathway. Among these, EcpC is the most dominant factor for FlhDC to positively regulate T3SS expression.

  10. Immunomodulatory effects of a polysaccharide from Tamarindus indica.

    Science.gov (United States)

    Sreelekha, T T; Vijayakumar, T; Ankanthil, R; Vijayan, K K; Nair, M K

    1993-04-01

    A polysaccharide isolated and purified from Tamarindus indica shows immunomodulatory activities such as phagocytic enhancement, leukocyte migration inhibition and inhibition of cell proliferation. These properties suggest that this polysaccharide from T. indica may have some biological applications.

  11. Representaciones femeninas en el cine: poder y género en la película Rosario Tijeras

    Directory of Open Access Journals (Sweden)

    Azul Kikey Castelli-Olvera

    2015-12-01

    Full Text Available En este trabajo se sostiene que la película Rosario Tijeras es un filme que puede considerarse feminista pues, Rosario Tijeras es una mujer empoderada que cuenta su propia historia. Lo anterior en consideración a que el empoderamiento enfocado desde el movimiento feminista y la perspectiva de género implica que las mujeres accedan en igual medida a los bienes materiales, intelectuales e ideológicos que permitan que tomen decisiones sobre sus cuerpos y sus vidas, se entiende que no en todos los casos el empoderamiento se da de manera positiva sino que puede manifestarse como confrontación con la propia estructura social. En este sentido desempeña un papel fundamental el contexto. Rosario Tijeras vive en un contexto definido por hombres, pero durante el desarrollo de la historia va asumiendo decisiones sobre su cuerpo y sobre su vida aún a costa de su propia seguridad, convirtiéndose en una transgresora. El análisis se realiza a partir de: 1. la propuesta de Scott, quien desagrega los elementos que constituyen la identidad de género y que en este trabajo funcionan como categorías; el análisis semiótico partiendo de Cirlot y Tresidder; y 2. El análisis formal a través de la descripción de antecedentes y uso del lenguaje cinematográfico

  12. La imagen de la España tardofranquista en las películas de Manolo Escobar

    Directory of Open Access Journals (Sweden)

    E Pérez Morán

    2013-03-01

    Full Text Available Nos acercamos al cine popular del tardofranquismo, del que estudiamos las 200 películas más taquilleras. Para este artículo analizamos, bajo técnicas cualitativas, el ciclo de filmes protagonizados entre 1966 y 1975 por el actor y cantante Manolo Escobar, al ser el más rentable económicamente y el más explícito en cuanto a sus mensajes. Pretendemos estudiar la transmisión de valores, ideas y creencias en este tipo de cine, que a priori se esconde bajo la fórmula del entretenimiento pero que en el fondo es un vehículo ideológico, como quedará demostrado. La preeminencia del macho, el servilismo de las mujeres, la explotación de otros tópicos celtibéricos del momento o el ensalzamiento de lo español hacia lo foráneo son algunas de las constantes de estas comedias musicales cuyos finales tranquilizadores concluían que el éxito estaba al alcance de cualquiera que acatara los códigos de conducta imperantes en la España tardofranquista.

  13. Ice nucleation activity of polysaccharides

    Science.gov (United States)

    Bichler, Magdalena; Felgitsch, Laura; Haeusler, Thomas; Seidl-Seiboth, Verena; Grothe, Hinrich

    2015-04-01

    Heterogeneous ice nucleation is an important process in the atmosphere. It shows direct impact on our climate by triggering ice cloud formation and therefore it has much influence on the radiation balance of our planet (Lohmann et al. 2002; Mishchenko et al. 1996). The process itself is not completely understood so far and many questions remain open. Different substances have been found to exhibit ice nucleation activity (INA). Due to their vast differences in chemistry and morphology it is difficult to predict what substance will make good ice nuclei and which will not. Hence simple model substances must be found and be tested regarding INA. Our work aims at gaining to a deeper understanding of heterogeneous ice nucleation. We intend to find some reference standards with defined chemistry, which may explain the mechanisms of heterogeneous ice nucleation. A particular focus lies on biological carbohydrates in regards to their INA. Biological carbohydrates are widely distributed in all kingdoms of life. Mostly they are specific for certain organisms and have well defined purposes, e.g. structural polysaccharides like chitin (in fungi and insects) and pectin (in plants), which has also water-binding properties. Since they are widely distributed throughout our biosphere and mostly safe to use for nutrition purposes, they are well studied and easily accessible, rendering them ideal candidates as proxies. In our experiments we examined various carbohydrates, like the already mentioned chitin and pectin, as well as their chemical modifications. Lohmann U.; A Glaciation Indirect Aerosol Effect Caused by Soot Aerosols; J. Geoph. Res.; Vol. 24 No.4; pp 11-1 - 11-4; 2002 Mishchenko M.I., Rossow W.B., Macke A., Lacis A. A.; Sensitivity of Cirrus Cloud Albedo, Bidirectional Reflectance and Optical Thickness Retrieval Accuracy to Ice Particle Shape, J. Geoph. Res.; Vol. 101, No D12; pp. 16,973 - 16,985; 1996

  14. Elucidation of interaction mechanism between lacquer polysaccharides and proteins

    OpenAIRE

    Bai, Yuting

    2013-01-01

    Lacquer polysaccharides, which exist in the sap of Asian lacquer tree, are highly branched acidic polysaccharides with 1,3-β-galactan backbone and glucouronic acid terminals. Lacquer polysaccharides were reported to be antitumor active and blood coagulation promoting effective, which specific activities might be caused from electrostatic attraction between negative-charged carboxyl groups from the uronic acid terminal of polysaccharides, and positive-charged amino groups from target proteins....

  15. Influence of polysaccharides on wine protein aggregation.

    Science.gov (United States)

    Jaeckels, Nadine; Meier, Miriam; Dietrich, Helmut; Will, Frank; Decker, Heinz; Fronk, Petra

    2016-06-01

    Polysaccharides are the major high-molecular weight components of wines. In contrast, proteins occur only in small amounts in wine, but contribute to haze formation. The detailed mechanism of aggregation of these proteins, especially in combination with other wine components, remains unclear. This study demonstrates the different aggregation behavior between a buffer and a model wine system by dynamic light scattering. Arabinogalactan-protein, for example, shows an increased aggregation in the model wine system, while in the buffer system a reducing effect is observed. Thus, we could show the importance to examine the behavior of wine additives under conditions close to reality, instead of simpler buffer systems. Additional experiments on melting points of wine proteins reveal that only some isoforms of thaumatin-like proteins and chitinases are involved in haze formation. We can confirm interactions between polysaccharides and proteins, but none of these polysaccharides is able to prevent haze in wine.

  16. Capsular Polysaccharide Expression in Commensal Streptococcus Species

    DEFF Research Database (Denmark)

    Skov Sørensen, Uffe B; Yao, Kaihu; Yang, Yonghong

    2016-01-01

    Expression of a capsular polysaccharide is considered a hallmark of most invasive species of bacteria, including Streptococcus pneumoniae, in which the capsule is among the principal virulence factors and is the basis for successful vaccines. Consequently, it was previously assumed that capsule...... evolved by import of cps fragments from commensal Streptococcus species, resulting in a mosaic of genes of different origins. The demonstrated antigenic identity of at least eight of the numerous capsular polysaccharide structures expressed by commensal streptococci with recognized serotypes of S. pneumoniae...... of Streptococcus pneumoniae and is the basis for successful vaccines against infections caused by this important pathogen. Contrasting with previous assumptions, this study showed that expression of capsular polysaccharides by the same genetic mechanisms is a general property of closely related species...

  17. Depolymerization of sulfated polysaccharides under hydrothermal conditions.

    Science.gov (United States)

    Morimoto, Minoru; Takatori, Masaki; Hayashi, Tetsuya; Mori, Daiki; Takashima, Osamu; Yoshida, Shinichi; Sato, Kimihiko; Kawamoto, Hitoshi; Tamura, Jun-ichi; Izawa, Hironori; Ifuku, Shinsuke; Saimoto, Hiroyuki

    2014-01-30

    Fucoidan and chondroitin sulfate, which are well known sulfated polysaccharides, were depolymerized under hydrothermal conditions (120-180°C, 5-60min) as a method for the preparation of sulfated polysaccharides with controlled molecular weights. Fucoidan was easily depolymerized, and the change of the molecular weight values depended on the reaction temperature and time. The degree of sulfation and IR spectra of the depolymerized fucoidan did not change compared with those of untreated fucoidan at reaction temperatures below 140°C. However, fucoidan was partially degraded during depolymerization above 160°C. Nearly the same depolymerization was observed for chondroitin sulfate. These results indicate that hydrothermal treatment is applicable for the depolymerization of sulfated polysaccharides, and that low molecular weight products without desulfation and deformation of the initial glycan structures can be obtained under mild hydrothermal conditions.

  18. Películas biodegradables a base de almidón: propiedades mecánicas, funcionales y biodegradación

    Directory of Open Access Journals (Sweden)

    Rafael Antonio Oropeza González

    2016-10-01

    Full Text Available El envasado es la principal fuente de desechos plásticos contaminantes. Del volumen total de desechos plásticos en el mundo, la mayor parte corresponde al envasado de alimentos. Las películas biodegradables han sido utilizadas en numerosas aplicaciones con diferentes aspectos debido a la versatilidad de sus propiedades y por factores medioambientales. El interés se ha incrementado en la búsqueda de materiales para envasado proveniente de fuentes renovables. Entre los polímeros utilizados, el almidón reviste el mayor interés por su abundancia en la naturaleza, biodegradabilidad, ser renovable y de bajo costo. Por sus limitaciones, permanentemente se llevan a cabo investigaciones que evalúan la mezcla del almidón con diversos componentes en el desarrollo de nuevas películas biodegradables. La literatura al respecto es considerable y en este trabajo parte de ella fue revisada y compilada, para dar una idea del estatus de las películas a base de almidón, con énfasis en las propiedades mecánicas.

  19. Efectos del fenómeno "El Niño 1997-98" sobre los principales recursos pelágicos en la costa peruana

    Directory of Open Access Journals (Sweden)

    Miguel Ñiquen

    2014-06-01

    Full Text Available En el período abril 1997 setiembre 1998 fueron realizados 5 cruceros de evaluación de los recursos pelágicos en la costa peruana, éstos permitieron observar cambios en la composición por especies, distribución, estructura por tamaño, reproducción y niveles poblacionales de los principales recursos pelágicos. Estos cambios guardan similitud con los observados en los eventos El Niño 1972-73 y 1982-83, especialmente en cuanto a la disminución de la biomasa de anchoveta y el incremento de otras especies pelágicas. En el período post-Niño se observó cambios notables en la estructura por tallas de anchoveta, mientras que la sardina, samas a y caballa coincidieron en mostrar buenos reclutamientos. La actividad reproductiva también se incrementó, inclusive en tallas juveniles, destacando la incidencia de sardinas sexualmente maduras con longitudes de 18-20 cm, situación que no había sido antes registrada.

  20. An objective method for mapping hazardous flow deposits from the stratigraphic record of stratovolcanoes: a case example from Montagne Pelée

    Science.gov (United States)

    Burt, M. L.; Wadge, G.; Curnow, R. N.

    2001-06-01

    A method is described that enables a variety of maps, which indicate the probabilities of deposition, to be constructed in a reproducible manner from the stratigraphie information typically available at well-studied stratovoicanoes. These maps can then be used as a basis for hazard assessment. The sampling of the deposits of previous eruptions is subject to uncertainties due to erosion, sectoral deposition and non-exposure. A model-based, iterative algorithm is used to compensate for the incomplete sampling. For each site, the available evidence from the other sites is used to estimate the probability of deposition for missing deposits. A geographical information system (GIS)-based method that uses Thiessen polygons to represent the presence or absence of deposits, together with simple cartographic rules based on depositional processes, then defines the extent of deposition. The combined operation of these two techniques is presented for Montagne Pelée in Martinique, using the amended stratigraphic record of Smith and Roobol (1990) for the past 6000 years. Three types of maps are created: maps for individual depositional events (the 1902 block-and-ash flow and surge deposits are used to verify the technique); maps for different deposit types aggregated over 6000 years of activity; and scenario maps which, in Montagne Pelée’s case, recognise that during the next Peléean or Plinian eruption a variety of hazards will have to be confronted.

  1. [Component analysis on polysaccharides in exocarp of Ginkgo biloba].

    Science.gov (United States)

    Song, G; Xu, A; Chen, H; Wang, X

    1997-09-01

    This paper reports the content and component analysis on polysaccharides in exocarp of Ginkgo biloba. The results show that the content of total saccharides is 89.7%; content of polysaccharides is 84.6%; content of reductic saccharides is 5.1%; the polysaccharides are composed of glucose, fructose, galactose and rhamnose.

  2. Galactomannan: a versatile biodegradable seed polysaccharide.

    Science.gov (United States)

    Prajapati, Vipul D; Jani, Girish K; Moradiya, Naresh G; Randeria, Narayan P; Nagar, Bhanu J; Naikwadi, Nikhil N; Variya, Bhavesh C

    2013-09-01

    Polysaccharides have been finding, in the last decades, very interesting and useful applications in the biomedical and, specifically, in the biopharmaceutical field. Galactomannans are a group of storage polysaccharides from various plant seeds that reserve energy for germination in the endosperm. There are four major sources of seed galactomannans: locust bean (Ceratonia siliqua), guar (Cyamopsis tetragonoloba), tara (Caesalpinia spinosa Kuntze), and fenugreek (Trigonella foenum-graecum L.). Through keen references of reported literature on galactomannans, in this review, we have described occurrence of various galactomannans, its physicochemical properties, characterization, applications, and overview of some major galactomannans.

  3. Studies on Sulfation of Lycium barbarum Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    YI,Jian-Ping; YAN,Hong; ZHONG,Ru-Gang

    2004-01-01

    @@ Polysaccharides can anti-virus, such as human immunodeficiency virus (HIV-1),[1] herpes simplex virus (HSV-1,HSV-2) and cytomegalovirus. Some of them are sulfates, e.g. dextran sulfate, heparin, sulfonation of chitosan and sulfated derivatives of Lentinan. Our results showed that sulfated derivatives of Lycium barbarum polysaccharides (LBP)have anti-HIV activity. Because the anti-HIV activity of LBP was deeply dependent on the molecular weight, the sulfation pattern and glycosidic branches besides degree of sulfation (DS), so we emphasized our work on the factors of DS.

  4. Ciencia de superficies e ingeniería de películas de diamante: de las propiedades morfológicas a las ópticas

    Directory of Open Access Journals (Sweden)

    Miguel Apátiga

    2003-01-01

    Full Text Available Para efectuar la caracterización morfológica y óptica en películas de diamante se utilizó la microscopía de barrido electrónico (MBE y espectroscopias de transformada de Fourier infrarroja (TFI y Raman. Para esto se depositaron diversas películas de diamante usando la flama de un soplete de oxígeno-acetileno a una temperatura del substrato de 800°C y en atmósfera abierta. Las micrografías MBE muestran que la morfología y espesor de las películas varían según las condiciones empleadas en su obtención. También hay información detallada acerca de la estructura en la superficie del diamante obtenida por espectroscopia infrarroja. De esta manera, se analiza la naturaleza de las especies químicamente absorbidas durante el proceso de crecimiento como resultado de la reacción química: C2H2 + O2 Æ 2CO + H2, llevada a cabo en los primeros instantes de la deposición. Además, se estudió la calidad de las películas mediante espectroscopia Raman, una de las técnicas más sensibles y poderosas, ya que permite distinguir las diferentes fases del carbón. Con esta técnica se obtuvo una banda en 1332 cm-1 que es característica de la estructura sp3 del diamante, la ausencia de señales alrededor de 1560 cm-1 es característico de las películas de diamante de buena calidad. Se presenta también una breve discusión del papel que juegan las especies químicamente absorbidas en los primeros instantes en que se produce la deposición del diamante y durante su proceso de crecimiento

  5. Improved coupling of bacterial polysaccharides to macromolecules and solid supports

    DEFF Research Database (Denmark)

    2013-01-01

    The invention relates to a method of producing a polysaccharide-carrier conjugate comprising coupling a polysaccharide to a carrier, said polysaccharide comprising at least one monosaccharide unit comprising a keto-carboxy group according to the formula -C(=O)COOR, where R is either hydrogen or C1......-alkoxyamine group of the carrier with a keto-carboxy group of said polysaccharide to form a covalent amide bond between the carrier and the polysaccharide. Another aspect of the present invention relates to a compound or solid surface obtained when performing the method of the present invention. A third aspect...

  6. The 13 ka Pelée-Type Dome Collapse at Nevado de Toluca Volcano, México.

    Science.gov (United States)

    D'Antonio, M.; Capra, L.; Sarocchi, D.; Bellotti, F.

    2007-05-01

    The Nevado de Toluca is an active volcano located in the central sector of the Trans-Mexican Volcanic Belt, 80 km southwest of Mexico City. Activity at this andesitic to dacitic stratovolcano began ca. 2.6 Ma ago. During the last 42 ka, the volcano has been characterized by different eruptive styles, including five dome collapses dated at 37, 32, 28, 26, and 13 ka and five Plinian eruptions at 42 ka, 36 ka, 21.7 ka, 12.1 ka and 10.5 ka. The 13 ka dome collapse is the youngest event of this type, and originated a 0.11 km3 block-and-ash flow deposit on the north-eastern sector of the volcano. The deposit consists of two facies: channel-like, 10 m thick, monolitologic, that is composed of up to five units, with decimetric dacitic clasts set in a sandy matrix; and a lateral facies that consists of a gray, sandy horizon, up to 4 m thick, with a 30 cm-thick surge layer at the base. The main component is a dacitic lava, with different degree of vesciculation, with mineral association of Pl-Hbl-Opx. Plagioclases show two different textures: in equilibrium, with normal zoning (core = An37-64.3, rim = An30.7-45.8) or with spongy cellular texture with inverse zoning (core = An38-43.5, rim = An45-51.2). Hornblende is normally light green, barren of oxidation. The rock matrix contains up to 53 perc. of glass with abundant microlites, indicating over-pressure on the crystallizing magma and a rapid expulsion. All these stratigraphic and petrographic features indicate that the dome was quickly extruded on the summit of the volcano, probably triggered by a magma mixing process, and its collapse was accompanied by an explosive component, being classified as a Pelée-type event.

  7. Fucoidans - sulfated polysaccharides of brown algae

    Energy Technology Data Exchange (ETDEWEB)

    Usov, Anatolii I; Bilan, M I [N.D.Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

    2009-08-31

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  8. Fucoidans — sulfated polysaccharides of brown algae

    Science.gov (United States)

    Usov, Anatolii I.; Bilan, M. I.

    2009-08-01

    The methods of isolation of fucoidans and determination of their chemical structures are reviewed. The fucoidans represent sulfated polysaccharides of brown algae, the composition of which varies from simple fucan sulfates to complex heteropolysaccharides. The currently known structures of such biopolymers are presented. A variety of the biological activities of fucoidans is briefly summarised.

  9. Polysaccharide coating of human corneal endothelium

    DEFF Research Database (Denmark)

    Schroder, H D; Sperling, S

    1977-01-01

    Electron microscopy revealed the presence of a 600-1500 A thick layer of polysaccharide on the surface of human corneal endothelial cells. The surface layer was visualized by combined fixation and staining in a mixture of ruthenium red and osmium tetroxide. The coating material was stable...

  10. SORPTION PROPERTIES OF PLANT POLYSACCHARIDE COMPLEXES

    Directory of Open Access Journals (Sweden)

    L. E. Glagoleva

    2012-01-01

    Full Text Available The article presents information on the laws of the sorption of water to grow-negative polysaccharide complexes of the pumpkin and briar, deter-mined the rate constant of swelling as a function of temperature and pH, the maximum degree of swelling and limit the time to achieve it.

  11. Immunomodulatory activities of five clinically used Chinese herbal polysaccharides

    Directory of Open Access Journals (Sweden)

    Aiping Lu

    2012-02-01

    Full Text Available Polysaccharide is a natural macromolecular compound with complex, important and multifaceted biological activities. Some of polysaccharides have been marketed in China as drugs or healthy products. More studies confirm that the active ingredient of many traditional Chinese medicine exist in the form of polysaccharides. They play a role in disease therapy by activating immune cells and the complement system; regulating the cytokines expression; promoting the production of antibodies; inhibiting tumor cell proliferation and inducing tumor cell apoptosis; inhibiting virus entering cells and replication; increasing activity of antioxidant enzyme; scavenging free radicals; and inhibiting lipid peroxidation. In this review, we focus on the immunomodulatory effects and its possible mechanism of polysaccharides from Chinese herbal polysaccharides products, including Lentinan, Astragalus polysaccharide, Polyporus polysaccharide and Achyranthes bidentata polysaccharide. The immunomodulatory activities of polysaccharides were categorized in the paper into general immunoregulatory activity, anti-tumor, anti-infections, anti-inflammatory, anti-oxidative, anti-mutagenic and radioprotective, anti-complementary, anti-adhesive, and anti-allergy since all the activities are related to modulate immune responses by the polysaccharides. Also the challenges in the research of polysaccharides will be discussed. [J Exp Integr Med 2012; 2(1.000: 15-27

  12. Sulfated polysaccharides and immune response: promoter or inhibitor?

    Science.gov (United States)

    Chen, D; Wu, X Z; Wen, Z Y

    2008-06-01

    Sulfated polysaccharides, which frequently connect to core protein, are expressed not only on cell surface but also throughout the extracellular matrix. Besides providing structural integrity of cells, sulfated polysaccharides interact with a variety of sulfated polysaccharides-binding proteins, such as growth factors, cytokines, chemokines and proteases. Sulfated polysaccharides play two-edged roles, inhibitor and promoter, in immune response. Some sulfated polysaccharides act as the immunosuppressor by blocking inflammatory signal transduction induced by proinflammatory cytokines, suppressing the activation of complement and inhibiting the process that leukocytes adhere to and pass through endothelium. On the contrary, the interaction between immune cells and sulfated polysaccharides produced by bacteria, endothelial cells and immune cells initiate the occurrence of immune response. It promotes the processes of recognizing and arresting antigen, migrating transendothelium, moving into and out of immune organ and enhancing the proliferation of lymphocyte. The structure of sulfated polysaccharides, such as molecular weight and sulfated sites heterogeneity, especially the degree of disaccharide sulfation, position of the sulfate moiety and organization of sulfated domains, may play critical role in their controversial effects. As a consequence, the interaction between sulfated polysaccharides and sulfated polysaccharide-binding proteins may be changed by modifying the structure of sulfated polysaccharides chains. The administration of drug targeting sulfated polysaccharide-protein interaction may be useful in treating inflammatory related diseases.

  13. Multiple Genes in a Single Host: Cost-Effective Production of Bacterial Laccase (cotA), Pectate Lyase (pel), and Endoxylanase (xyl) by Simultaneous Expression and Cloning in Single Vector in E. coli

    Science.gov (United States)

    Kumar, Sandeep; Jain, Kavish Kumar; Bhardwaj, Kailash N.; Chakraborty, Subhojit; Kuhad, Ramesh Chander

    2015-01-01

    This study attempted to reduce the enzyme production cost for exploiting lignocellulosic materials by expression of multiple genes in a single host. Genes for bacterial laccase (CotA), pectate lyase (Pel) and endoxylanase (Xyl), which hold significance in lignocellulose degradation, were cloned in pETDuet-1 vector containing two independent cloning sites (MCS). CotA and xyl genes were cloned in MCS1 and MCS 2, respectively. Pel gene was cloned by inserting complete cassette (T7 promoter, ribosome binding site, pel gene, His tag and complete gene ORF) preceded by cotA open reading frame in the MCS1. IPTG induction of CPXpDuet-1 construct in E. coli BL21(DE3) resulted in expression of all three heterologous proteins of ~65 kDa (CotA), ~45 kDa (Pel) and ~25 kDa (Xyl), confirmed by SDS-PAGE and western blotting. Significant portions of the enzymes were also found in culture supernatant (~16, ~720 and ~370 IU/ml activities of CotA, Pel and Xyl, respectively). Culture media optimization resulted in 2, 3 and 7 fold increased secretion of recombinant CotA, Pel and Xyl, respectively. Bioreactor level optimization of the recombinant cocktail expression resulted in production of 19 g/L dry cell biomass at OD600nm 74 from 1 L induced culture after 15 h of cultivation, from which 9, 627 and 1090 IU/ml secretory enzyme activities of CotA, Xyl and Pel were obtained, respectively. The cocktail was also found to increase the saccharification of orange peel in comparison to the xylanase alone. Thus, simultaneous expression as well as extra cellular secretion of these enzymes as cocktail can reduce the enzyme production cost which increases their applicability specially for exploiting lignocellulosic materials for their conversion to value added products like alcohol and animal feed. PMID:26642207

  14. Seismic properties of volcanic rocks from Montagne Pelée (Martinique, Lesser Antilles) and their relations to transport properties

    Science.gov (United States)

    Bernard, M.-L.; Zamora, M.

    2012-04-01

    Numerous laboratory and theoretical studies on the physical properties of rocks and their relationships - lead mainly in the framework of petroleum exploration - show that rock physics is necessary for an accurate quantitative interpretation of geophysical observations. Moreover joint inversion of different geophysical datasets is emerging as an important tool to enhance resolution and decrease inversion artifacts in imaging of structurally complex areas such as volcanoes. In many cases, the coupling between the inverted parameters is based on empirical or theoretical relationships derived from laboratory data. Consequently rock physics can be used to: interpret simultaneously several geophysical datasets on volcanoes when they are available, improve the imaging of volcano structures, and better understand the coupled processes that can occur during volcanic unrest. It's in this context that we lead a laboratory study on the transport properties (permeability, thermal and electrical conductivities) and seismic properties (velocity and attenuation of P and S waves) of volcanic rocks representative of Montagne Pelée (Martinique) deposits. In this presentation we will focus on (1) the seismic properties and (2) the relations between seismic and transport properties. The 43 samples collected are representative of the main lithological units of this volcano: vesicular lava blocks and indurated ashed from indurated block-and-ash flows also called breccias, vesicular lava blocks from "Pelean nuee ardente" flows, scoriae from scoria flows, pumices from ash-and-pumices flows, and dense lava blocks from lava flows and lava domes. Their total porosity varies over a wide range from 4 to 73%. Since the samples present similar chemical and mineralogical compositions (andesites), the main difference between the samples comes from their pore structure and reflects differences in the mechanisms of magma degassing and vesiculation during their formation (Bernard et al., 2007). This

  15. Películas biodegradables a base de almidón: propiedades mecánicas, funcionales y biodegradación

    OpenAIRE

    Rafael Antonio Oropeza González; Adriana Isabel Montes Hernández; Carlos Alberto Padrón Pereira

    2016-01-01

    El envasado es la principal fuente de desechos plásticos contaminantes. Del volumen total de desechos plásticos en el mundo, la mayor parte corresponde al envasado de alimentos. Las películas biodegradables han sido utilizadas en numerosas aplicaciones con diferentes aspectos debido a la versatilidad de sus propiedades y por factores medioambientales. El interés se ha incrementado en la búsqueda de materiales para envasado proveniente de fuentes renovables. Entre los polímeros utilizados, el ...

  16. Películas y recubrimientos comestibles: una alternativa favorable en la conservación poscosecha de frutas y hortalizas

    OpenAIRE

    Daybelis Fernández Valdés; Silvia Bautista Baños; Dayvis Fernández Valdés; Arturo Ocampo Ramírez; Annia García Pereira; Alejandro Falcón Rodríguez

    2015-01-01

    El creciente interés de los consumidores hacia productos sanos, nutritivos, naturales y que beneficiosos para la salud, ha orientado y motivado investigaciones hacia el desarrollo de películas y recubrimientos comestibles aplicados a productos hortofrutícolas, como una alternativa para cubrir estas necesidades. Estos se aplican con el objetivo de extender la vida útil de los alimentos y proveen la posibilidad de mejorar la seguridad del producto mediante la limitación de transferencia de hume...

  17. Características endocrinas, moleculares y de parámetros de crecimiento asociados a la obesidad del cerdo Pelón Mexicano

    OpenAIRE

    Carmen Camacho-Rea; Carlos G. Gutiérrez; Miguel E. Arechavaleta-Velasco; Laura Díaz-Cueto; Fabián J. Arechavaleta-Velasco; Roberto Martínez Rodríguez; Clemente Lemus-Flores; Rogelio A. Alonso-Morales

    2008-01-01

    Para determinar el potencial del cerdo Pelón Mexicano (CPM) en el estudio de la obesidad, se realizó un estudio entre el CPM y cerdos Landrace-Yorkshire (CLY). Se midieron concentraciones séricas de leptina e insulina y se determinó su correlación con el espesor de grasa dorsal (EGD). Se evaluó el consumo de alimento (CA), el EGD, la ganancia diaria de peso y la expresión de genes que codifican para leptina, el receptor de leptina, adiponectina y el receptor activado por proliferadores de per...

  18. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    Directory of Open Access Journals (Sweden)

    José Gabriel Ferreras Rodríguez

    2008-01-01

    Full Text Available El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples of intentional pictorial organization so as to convey specific meanings.

  19. Cine y memoria cultural: la ilusión del multiculturalismo a partir de dos películas mexicanas de animación

    OpenAIRE

    Julián Woodside

    2012-01-01

    Este texto aborda cómo es que en México se ha construido la ilusión de un multiculturalismo mediante un "racismo asimilacionista" apoyado en la idea reduccionista de lo "mexicano" como la mezcla de lo "hispano" y lo "indígena". A partir de un análisis semiohistórico de dos películas mexicanas de animación infantil, "La leyenda de la Nahuala" (2007) de Ricardo Arnaiz y "Héroes Verdaderos. Episodio: Independencia" (2010) de Carlos Kuri; así como una discusión sobre la construcción de narrativas...

  20. Películas delgadas de Al2O3 sobre silicio preparadas por ablación láser

    Directory of Open Access Journals (Sweden)

    Lamagna, A.

    1998-04-01

    Full Text Available Al2O3 thin films were fabricated by pulsed laser deposition (PLD on Si3N4/Si, to improve the thermal and electrical isolation of gas sensing devices. The microstructure of the films is analyzed as a function of the deposition conditions (laser fluence, oxygen pressure, target-substrate distance and substrate temperature. X-ray analysis shows that only a sharp peak that coincides with the corundum (116 reflection can be observed in all the films. But, when they are annealed at temperatures above 1,200°C, a change in the crystalline structure of some films occurs. The stoichiometry and morphology of the films with and without thermal treatment are compared using environmental scanning electron microscopy (SEM and EDAX analysis.

    Se depositaron películas delgadas de Al2O3 por ablación láser sobre Si3N4/Si para utilizarlas como aislante térmico y eléctrico en dispositivos sensores de gases. Se analiza la microestructura de estas películas en función de las condiciones de la deposición (densidad de energía del láser, presión de oxígeno, distancia blanco-substrato y temperatura del substrato. Los estudios de difracción de rayos X, utilizando geometría de ángulo rasante, muestran que sólo puede observarse la reflexión coincidente con la (116 del corundum. Cuando las películas se tratan térmicamente a temperaturas superiores a 1.200°C sufren un cambio en su cristalinidad que depende de las condiciones de la deposición. Utilizando microscopía electrónica de barrido (SEM y análisis por EDAX, se comparan la estequiometría y la morfología de las películas con y sin tratamiento térmico.

  1. Lecturas críticas y oposicionales de películas de Hollywood por jóvenes mexicanos: el caso de Ángeles y Demonios

    OpenAIRE

    Lozano Rendón, José Carlos; Frankenberg, Lorena

    2014-01-01

    Al igual que en muchos otros países del mundo, las superproducciones de Hollywood son sumamente exitosasen el mercado mexicano. Cada año, millones de personas van a las salas de cine y ven numerosas películasprocedentes del poderoso vecino del Norte. A pesar de la fuerte popularidad de los estudios culturales enMéxico y la histórica preocupación en el país por el impacto ideológico de las importaciones audiovisualesestadounidenses en la identidad cultural de las audiencias, los estudios empír...

  2. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    OpenAIRE

    Ferreras Rodríguez, José Gabriel; Leite, Lucimeire Virgilio

    2008-01-01

    El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples ...

  3. A vueltas con la alfabetización visual: lenguaje y significado en las películas de Wes Anderson

    OpenAIRE

    José Gabriel Ferreras Rodríguez; Lucimeire Vergilio Leite

    2008-01-01

    El presente artículo tiene por objetivo discutir algunos elementos del concepto de la alfabetización visual, aplicando, luego, las herramientas de análisis de imágenes a las películas de Wes Anderson, como ejemplos del manejo intencional de las imágenes para transmitir determinados significados. The present article aims to discuss, firstly, some elements encompassed in the definition of visual literary and, secondly, to apply some image analysis tools to Wes Anderson’s movies, as examples of...

  4. Cine Como Espejo Social: El Análisis De La Narrativa De La Película La Casa De Las Dagas Voladoras De Zhang Yimou

    Directory of Open Access Journals (Sweden)

    Xin WANG

    2014-10-01

    Full Text Available El cine de artes marciales, que mezcla y armoniza tanto artes marciales y óperas tradicionales como literatura, se asemeja al género de western en el cine de Estados Unidos. Muy delimitado en China se constituye en un importante género nacional del cine narrativo. En el siglo XXI las películas de artes marciales, basadas en las culturas tradicionales, introducen innovaciones importantes en cuanto a las formas de presentación y estilos narrativos, logrando una importante repercusión tanto comercial como artística.

  5. Análisis molecular, proteómico y filogenético de lazona pelúcida de mamíferos

    OpenAIRE

    Moros Nicolás, Carla

    2015-01-01

    INTRODUCCIÓN La zona pelúcida (ZP) es una matriz traslúcida, glicoproteica y acelular que rodea los ovocitos de los mamíferos implicada en importantes procesos durante la fecundación. Se ha considerado que la ZP estaba constituida por tres glicoproteínas (ZP1, ZP2 y ZP3) teniendo en cuenta estudios realizados en el ratón. Sin embargo, estudios posteriores demostraron que la ZP de cerda y de vaca también presentaba tres glicoproteínas, pero no estando presente en estos casos ZP1, siendo la...

  6. Cine Como Espejo Social: El Análisis De La Narrativa De La Película La Casa De Las Dagas Voladoras De Zhang Yimou

    OpenAIRE

    2014-01-01

    El cine de artes marciales, que mezcla y armoniza tanto artes marciales y óperas tradicionales como literatura, se asemeja al género de western en el cine de Estados Unidos. Muy delimitado en China se constituye en un importante género nacional del cine narrativo. En el siglo XXI las películas de artes marciales, basadas en las culturas tradicionales, introducen innovaciones importantes en cuanto a las formas de presentación y estilos narrativos, logrando una importante repercusión tanto come...

  7. POLYPEPTIDE AND POLYSACCHARIDE PROCESSING IN HYPERTHERMOPHILIC MICROORGANISMS

    Energy Technology Data Exchange (ETDEWEB)

    KELLY, ROBERT M.

    2008-12-22

    This project focused on the microbial physiology and biochemistry of heterotrophic hyperthermophiles with respect to mechanisms by which these organisms process polypeptides and polysaccharides under normal and stressed conditions. Emphasis is on two model organisms, for which completed genome sequences are available: Pyrococcus furiosus (growth Topt of 98°C), an archaeon, and Thermotoga maritima (growth Topt of 80°C), a bacterium. Both organisms are obligately anaerobic heterotrophs that reduce sulfur facultatively. Whole genome cDNA spotted microarrays were used to follow transcriptional response to a variety of environmental conditions in order to identify genes encoding proteins involved in the acquisition, synthesis, processing and utilization of polypeptides and polysaccharides. This project provided new insights into the physiological aspects of hyperthermophiles as these relate to microbial biochemistry and biological function in high temperature habitats. The capacity of these microorganisms to produce biohydrogen from renewable feedstocks makes them important for future efforts to develop biofuels.

  8. Structural characterization of polysaccharides from bamboo

    Science.gov (United States)

    Kamil, Ruzaimah Nik Mohamad; Yusuf, Nur'aini Raman; Yunus, Normawati M.; Yusup, Suzana

    2014-10-01

    The alkaline and water soluble polysaccharides were isolate by sequential extractions with distilled water, 60% ethanol containing 1%, 5% and 8% NaOH. The samples were prepared at 60 °C for 3 h from local bamboo. The functional group of the sample were examined using FTIR analysis. The most precipitate obtained is from using 60% ethanol containing 8% NaOH with yield of 2.6%. The former 3 residues isolated by sequential extractions with distilled water, 60% ethanol containing 1% and 5% NaOH are barely visible after filtering with cellulose filter paper. The FTIR result showed that the water-soluble polysaccharides consisted mainly of OH group, CH group, CO indicates the carbohydrate and sugar chain. The sample weight loss was slightly decreased with increasing of temperature.

  9. Pneumococcal capsular polysaccharide structure predicts serotype prevalence.

    Directory of Open Access Journals (Sweden)

    Daniel M Weinberger

    2009-06-01

    Full Text Available There are 91 known capsular serotypes of Streptococcus pneumoniae. The nasopharyngeal carriage prevalence of particular serotypes is relatively stable worldwide, but the host and bacterial factors that maintain these patterns are poorly understood. Given the possibility of serotype replacement following vaccination against seven clinically important serotypes, it is increasingly important to understand these factors. We hypothesized that the biochemical structure of the capsular polysaccharides could influence the degree of encapsulation of different serotypes, their susceptibility to killing by neutrophils, and ultimately their success during nasopharyngeal carriage. We sought to measure biological differences among capsular serotypes that may account for epidemiological patterns. Using an in vitro assay with both isogenic capsule-switch variants and clinical carriage isolates, we found an association between increased carriage prevalence and resistance to non-opsonic neutrophil-mediated killing, and serotypes that were resistant to neutrophil-mediated killing tended to be more heavily encapsulated, as determined by FITC-dextran exclusion. Next, we identified a link between polysaccharide structure and carriage prevalence. Significantly, non-vaccine serotypes that have become common in vaccinated populations tend to be those with fewer carbons per repeat unit and low energy expended per repeat unit, suggesting a novel biological principle to explain patterns of serotype replacement. More prevalent serotypes are more heavily encapsulated and more resistant to neutrophil-mediated killing, and these phenotypes are associated with the structure of the capsular polysaccharide, suggesting a direct relationship between polysaccharide biochemistry and the success of a serotype during nasopharyngeal carriage and potentially providing a method for predicting serotype replacement.

  10. INTERACTION OF IONIC LIQUIDS WITH POLYSACCHARIDES

    OpenAIRE

    2008-01-01

    The use of ionic liquids (ILs) in the field of cellulose chemistry opens up a broad variety of new opportunities. Besides the regeneration of the biopolymer to fibers, films, and beads, this new class of cellulose solvents is particularly useful for the homogeneous chemical modification of the polysaccharide. In this review, the potential of ILs as a reaction medium for the homogeneous cellulose functionalization is discussed. It is shown that numerous conversions proceed very efficiently and...

  11. Exposición de adolescentes de escuela secundaria de la Argentina y México a escenas de tabaco en películas de cine: una estimación poblacional

    Directory of Open Access Journals (Sweden)

    María V. Salgado

    2016-04-01

    Full Text Available Introducción: el tabaquismo en películas promueve el inicio de tabaquismo en adolescentes Objetivo: estimar el nivel de exposición a imágenes de tabaco contenidas en películas vistas por adolescentes de Argentina y México Métodos: Se realizó una encuesta a alumnos de primer año del secundario de Argentina y México. Se analizaron las 100 películas con mayor recaudación en cada año del periodo 2009-2013 (Argentina y 2010-2014 (México. A cada participante se le asignó una muestra aleatoria de 50 de estas películas, preguntándosele si la había visto. Se estimó el número total de adolescentes que habían visto cada película en cada país, y se multiplicó por el número de escenas que contenían tabaco (ocurrencias en cada película para así obtener el número de impresiones crudas de tabaco vista por los adolescentes escolarizados de cada país. Resultados: Se analizaron 422 films en Argentina y 433 en México. Más de 500 millones de imágenes de tabaco fueron vistas por la población joven de cada país, lo que promedia 128 y 121 minutos de escenas con tabaquismo por cada adolescente en Argentina y México respectivamente. Si bien los films calificados para mayores de 15/16/18 años tenían mayor promedio por película de escenas de tabaco, las películas calificadas para menores de esta edad fueron responsables de la mayor cantidad de escenas de tabaquismo vistas por adolescentes (67,3% en Argentina y 54,4% en México debido a su mayor audiencia. Conclusiones: A nivel poblacional son las películas para niños las máximas responsables de la carga de tabaco vista por adolescentes.

  12. Plant Cell Wall Matrix Polysaccharide Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Ajay Pal S. Sandhu; Gursharn S. Randhawa; Kanwarpal S. Dhugga

    2009-01-01

    The wall of an expanding plant cell consists primarily of cellulose microfibrils embedded in a matrix of hemi-cellulosic and pectic polysaccharides along with small amounts of structural and enzymatic proteins. Matrix polysacchar-ides are synthesized in the Golgi and exported to the cell wall by exocytosis, where they intercalate among cellulose microfibrUs, which are made at the plasma membrane and directly deposited into the cell wall. Involvement of Golgi glucan synthesis in auxin-induced cell expansion has long been recognized; however, only recently have the genes corresponding to glucan synthases been identified. Biochemical purification was unsuccessful because of the labile nature and very low abundance of these enzymes. Mutational genetics also proved fruitless. Expression of candidate genes identified through gene expression profiling or comparative genomics in heterologous systems followed by functional characterization has been relatively successful. Several genes from the cellulose synthase-like (Cs/) family have been found to be involved in the synthesis of various hemicellulosic glycans. The usefulness of this approach, however, is limited to those enzymes that probably do not form complexes consisting of unrelated proteins. Nonconventional approaches will continue to incre-mentally unravel the mechanisms of Golgi polysaccharide biosynthesis.

  13. Iron oxyhydroxide mineralization on microbial extracellular polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Clara S.; Fakra, Sirine C.; Edwards, David C.; Emerson, David; Banfield, Jillian F.

    2010-06-22

    Iron biominerals can form in neutral pH microaerophilic environments where microbes both catalyze iron oxidation and create polymers that localize mineral precipitation. In order to classify the microbial polymers that influence FeOOH mineralogy, we studied the organic and mineral components of biominerals using scanning transmission X-ray microscopy (STXM), micro X-ray fluorescence ({mu}XRF) microscopy, and high-resolution transmission electron microscopy (HRTEM). We focused on iron microbial mat samples from a creek and abandoned mine; these samples are dominated by iron oxyhydroxide-coated structures with sheath, stalk, and filament morphologies. In addition, we characterized the mineralized products of an iron-oxidizing, stalk-forming bacterial culture isolated from the mine. In both natural and cultured samples, microbial polymers were found to be acidic polysaccharides with carboxyl functional groups, strongly spatially correlated with iron oxyhydroxide distribution patterns. Organic fibrils collect FeOOH and control its recrystallization, in some cases resulting in oriented crystals with high aspect ratios. The impact of polymers is particularly pronounced as the materials age. Synthesis experiments designed to mimic the biomineralization processes show that the polysaccharide carboxyl groups bind dissolved iron strongly but release it as mineralization proceeds. Our results suggest that carboxyl groups of acidic polysaccharides are produced by different microorganisms to create a wide range of iron oxyhydroxide biomineral structures. The intimate and potentially long-term association controls the crystal growth, phase, and reactivity of iron oxyhydroxide nanoparticles in natural systems.

  14. Rheological studies of polysaccharides for skin scaffolds.

    Science.gov (United States)

    Almeida, Nalinda; Mueller, Anja; Hirschi, Stanley; Rakesh, Leela

    2014-05-01

    Polysaccharide hydrogels are good candidates for skin scaffolds because of their inherent biocompatibility and water transport properties. In the current study, hydrogels were made from a mixture of four polysaccharides: xanthan gum, konjac gum, iota-carrageenan, and kappa-carrageenan. Gel formation, strength, and structure of these polysaccharides were studied using rheological and thermal techniques. All gel samples studied were strong gels at all times because of the gradual water loss. However, after 12 h of storage, elastic (G') and loss (G'') moduli of hydrogel mixture containing all the ingredients is of one to two orders of magnitude greater than that of mixtures not containing either xanthan gum or iota-carrageenan, which confirmed the varied levels of gel strength. This is mainly due to the rate of water loss in each of these mixtures, resulting in gels of varying structures and dynamic moduli over a period of time. Iota-carrageenan and xanthan gum differ in their effect on gel strength and stability in combination with konjac gum and kappa-carrageenan.

  15. Marine Origin Polysaccharides in Drug Delivery Systems

    Directory of Open Access Journals (Sweden)

    Matias J. Cardoso

    2016-02-01

    Full Text Available Oceans are a vast source of natural substances. In them, we find various compounds with wide biotechnological and biomedical applicabilities. The exploitation of the sea as a renewable source of biocompounds can have a positive impact on the development of new systems and devices for biomedical applications. Marine polysaccharides are among the most abundant materials in the seas, which contributes to a decrease of the extraction costs, besides their solubility behavior in aqueous solvents and extraction media, and their interaction with other biocompounds. Polysaccharides such as alginate, carrageenan and fucoidan can be extracted from algae, whereas chitosan and hyaluronan can be obtained from animal sources. Most marine polysaccharides have important biological properties such as biocompatibility, biodegradability, and anti-inflammatory activity, as well as adhesive and antimicrobial actions. Moreover, they can be modified in order to allow processing them into various shapes and sizes and may exhibit response dependence to external stimuli, such as pH and temperature. Due to these properties, these biomaterials have been studied as raw material for the construction of carrier devices for drugs, including particles, capsules and hydrogels. The devices are designed to achieve a controlled release of therapeutic agents in an attempt to fight against serious diseases, and to be used in advanced therapies, such as gene delivery or regenerative medicine.

  16. Diversity of Cyclic Di-GMP-Binding Proteins and Mechanisms.

    Science.gov (United States)

    Chou, Shan-Ho; Galperin, Michael Y

    2016-01-01

    Cyclic di-GMP (c-di-GMP) synthetases and hydrolases (GGDEF, EAL, and HD-GYP domains) can be readily identified in bacterial genome sequences by using standard bioinformatic tools. In contrast, identification of c-di-GMP receptors remains a difficult task, and the current list of experimentally characterized c-di-GMP-binding proteins is likely incomplete. Several classes of c-di-GMP-binding proteins have been structurally characterized; for some others, the binding sites have been identified; and for several potential c-di-GMP receptors, the binding sites remain to be determined. We present here a comparative structural analysis of c-di-GMP-protein complexes that aims to discern the common themes in the binding mechanisms that allow c-di-GMP receptors to bind it with (sub)micromolar affinities despite the 1,000-fold excess of GTP. The available structures show that most receptors use their Arg and Asp/Glu residues to bind c-di-GMP monomers, dimers, or tetramers with stacked guanine bases. The only exception is the EAL domains that bind c-di-GMP monomers in an extended conformation. We show that in c-di-GMP-binding signature motifs, Arg residues bind to the O-6 and N-7 atoms at the Hoogsteen edge of the guanine base, while Asp/Glu residues bind the N-1 and N-2 atoms at its Watson-Crick edge. In addition, Arg residues participate in stacking interactions with the guanine bases of c-di-GMP and the aromatic rings of Tyr and Phe residues. This may account for the presence of Arg residues in the active sites of every receptor protein that binds stacked c-di-GMP. We also discuss the implications of these structural data for the improved understanding of the c-di-GMP signaling mechanisms.

  17. Synthetic Polymer Nanoparticle-Polysaccharide Interactions: A Systematic Study

    OpenAIRE

    Zeng, Zhiyang; Patel, Jiten; Lee, Shih-Hui; McCallum, Monica; Tyagi, Anuradha; Yan, Mingdi; Shea, Kenneth J.

    2012-01-01

    The interaction between synthetic polymer nanoparticles (NPs) and biomacromolecules (e.g. proteins, lipids and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g. heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play critical roles in many biological processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR and an anticoagulant as...

  18. Structural Analysis of Polysaccharide from Cladonia furcatar and Its Activities

    Institute of Scientific and Technical Information of China (English)

    CHEN Qian; LIN Xin; CAI YuJun; LI ZhiXiao

    2001-01-01

    @@ Cladonia furcatar is a member of the lichens genus Cladonia. Japanese scientific researchers [1] made a great achievement in selecting lichens as anticancer agent and polysaccharides are generally considered to be their main bioactive constituents. Recently, Iacomini et al[2] have investigated the members of the genus Cladonia, a mannose-containing polysaccharide was isolated from Cladoniafurcatar. We now report the new chemical structure of polysaccharide from Cladoniafurcatar and its activities.

  19. Oligo- and polysaccharide synthesis by Rhizobium leguminosarum and Rhizobium meliloti.

    OpenAIRE

    Breedveld, M W

    1992-01-01

    Rhizobium and Agrobacterium species are capable of synthesizing a variety of extracellular and cellular oligo- and polysaccharides. Changes in environmental conditions may all affect the composition, physical properties, and relative amounts of oligo- and polysaccharides. Interest in the field of Rhizobium polys accharides has resulted from a development in two distinct areas, (i) the role of oligo- and polysaccharides in the microbe- plant interaction, and (ii) studies on the physico- chemic...

  20. Structural Analysis of Polysaccharide from Cladonia furcatar and Its Activities

    Institute of Scientific and Technical Information of China (English)

    CHEN; Qian

    2001-01-01

    Cladonia furcatar is a member of the lichens genus Cladonia. Japanese scientific researchers [1] made a great achievement in selecting lichens as anticancer agent and polysaccharides are generally considered to be their main bioactive constituents. Recently, Iacomini et al[2] have investigated the members of the genus Cladonia, a mannose-containing polysaccharide was isolated from Cladoniafurcatar. We now report the new chemical structure of polysaccharide from Cladoniafurcatar and its activities.  ……

  1. Antiviral polysaccharides isolated from Hong Kong brown seaweed Hydroclathrus clathratus

    Institute of Scientific and Technical Information of China (English)

    WANG; Hui; OOI; Engchoon; Vincent; ANG; Put; O; Jr.

    2007-01-01

    Two relatively pure polysaccharides H3-a1 and H3-b1 had been isolated from the brown seaweed Hydroclathrus clathratus. They were characterized by HPLC, ultraviolet scanning, gas chromatography, infrared spectroscopy and elemental analysis, and shown to be two different sulfated polysaccharides with different monosaccharide content, but both with high relative molecular mass. They contained some proteins and uronic acid respectively. The sulfate content and bioactivity of these polysaccharides varied during purification. The fractions derived from the hot water extract also exhibited low anticoagulant effect. This is the first time that the antiherpetic and anticoagulant activities were evaluated for the polysaccharides from the Hong Kong brown seaweed Hydroclathrus clathratus.

  2. Películas y recubrimientos comestibles: una alternativa favorable en la conservación poscosecha de frutas y hortalizas

    Directory of Open Access Journals (Sweden)

    Daybelis Fernández Valdés

    2015-01-01

    Full Text Available El creciente interés de los consumidores hacia productos sanos, nutritivos, naturales y que beneficiosos para la salud, ha orientado y motivado investigaciones hacia el desarrollo de películas y recubrimientos comestibles aplicados a productos hortofrutícolas, como una alternativa para cubrir estas necesidades. Estos se aplican con el objetivo de extender la vida útil de los alimentos y proveen la posibilidad de mejorar la seguridad del producto mediante la limitación de transferencia de humedad, oxígeno y compuestos responsables del sabor, color y aroma. El empleo de películas y recubrimientos comestibles a base de polisacáridos, proteínas, lípidos, aditivos y compuestos activos ha jugado un papel importante en la industria de alimentos y han demostrado ser efectivos en la conservación de frutas y hortalizas controlando transferencia de gases, crecimiento microbiano, así como manteniendo las características deseadas por los consumidores como, apariencia fresca, firmeza, brillo, color, calidad y valor comercial. La finalidad de esta revisión bibliográfica es demostrar que la utilización de cubiertas comestibles ayuda a la conservación y calidad de frutas y hortalizas.

  3. Caracterización estructural y morfológica de películas de ZnO crecidas sobre sustratos de vidrio

    Directory of Open Access Journals (Sweden)

    LUIS MORENO MONTOYA

    2007-01-01

    Full Text Available Utilizando la técnica PAPVD (Plasma Assisted Physical Vapor Deposition por arco pulsado se crecieron películas delgadas de ZnO sobre sustratos de vidrio. Las películas fueron crecidas variando el voltaje de la descarga, la presión del gas y el número de descargas. Las propiedades estructurales tales como: cristalinidad, microestructura y rugosidad superficial fueron investigadas por Difracción de Rayos X, Microscopía Electrónica de Barrido en Ambiente y Microscopía de Fuerza Atómica. Se encontró que el material depositado es efectivamente ZnO, con una estructura cristalina hexagonal, una orientación preferencial en la dirección (002, alta textura cristalográfica, parámetros de red promedio de a = 3,250495 Å y c =5,21608 Å, espesores con valores del orden de los cientos de nanómetros, tamaño de grano promedio del orden de 0,529 µm y rugosidad promedio de 98,6 Å, además, se detectó la presencia de irregularidades, grietas y microgotas en la superficie de las mismas.

  4. Comportamiento hidrodinámico de un reactor electroquímico para recuperar residuos en la fabricación de películas semiconductoras

    Directory of Open Access Journals (Sweden)

    Luis Adrián Echeverri Holguin

    2013-12-01

    Full Text Available En el laboratorio de optoelectrónica adscrito a la Universidad del Quindío se encuentra implementada la técnica Epitaxia en fase líquida, utilizada para elaborar películas semiconductoras de GaInAsSb, la cual genera, en promedio, un desecho de 1457 mg, constituido, en mayor proporción, por galio, indio y antimonio, que pueden ser recuperados por procesos electroquímicos. El propósito de este estudio fue reciclar y cristalizar estos metales puros a bajo costo, con cero productos de desechos metálicos en la fabricación de películas semiconductoras. Los estudios se llevaron a cabo en un reactor electroquímico de compartimentos separados, inyectando una solución trazadora de NaCl en el compartimento catódico, determinándose la conductividad a la entrada y a la salida del reactor, y describiendo con ello un modelo matemático del comportamiento hidrodinámico, mediante la distribución de tiempos de residencia (DTR, y así aplicarlo para la recuperación de estos metales, operando el equipo a intensidad constante (modo galvanostático y a potencial constante (modo potenciostático.

  5. Effects of Protein Level and Mangosteen Peel Pellets (Mago-pel) in Concentrate Diets on Rumen Fermentation and Milk Production in Lactating Dairy Crossbreds

    Science.gov (United States)

    Norrapoke, T.; Wanapat, M.; Wanapat, S.

    2012-01-01

    Four, lactating dairy crossbreds (50%×50% Holstein Friesian×Native Zebu cattle) were randomly assigned according to a 2×2 factorial arrangement (two protein levels and two levels of mangosteen peel pellets (Mago-pel)) in a 4×4 Latin square design to receive four dietary treatments. All cows received concentrate at a proportion of 1 kg concentrate per 2 kg of milk yield, and urea-treated 5% rice straw (UTRS) was given ad libitum. It was found that total dry matter intakes, nutrient digestibility, ruminal pH and NH3-N concentrations were not affected (p>0.05) by treatments. Concentrations of ruminal pH and NH3-N were not affected by dietary treatments although the concentration of BUN varied significantly (p0.05); however, the population of protozoa was decreased (p0.05) among dietary treatments (p>0.05); however, copy numbers of Ruminococcus flavefaciens was increased when protein level increased (p0.05) milk composition except solids-not-fat which was higher in cows fed the diet with 19% CP. Therefore, feeding a concentrate containing 16% CP together with 300 g/hd/d Mago-pel supplementation results in changes in rumen fermentation and microbial population and improvements in milk production in lactating dairy crossbreds fed on UTRS. PMID:25049652

  6. Propiedades estructurales, eléctricas y mecánicas de películas delgadas obtenidas por métodos de evaporación asistidos por plasma

    OpenAIRE

    Broitman, Esteban D.

    1997-01-01

    Se estudiaron las propiedades estructurales, eléctricas y mecánicas de películas delgadas obtenidas por dos métodos de evaporación asistidos por plasma: "thermal ion plating" y "sputter-ion-plating". Con la primera configuración se estudió la influencia de un plasma en la microestructura de películas metálicas. El flujo de partículas bombardeantes del sustrato y la película, con energía media del orden de los cientos de electron-volt, produce varias características únicas de nucleación y crec...

  7. Análisis de los referentes culturales y argot en la película escocesa 'Trainspotting' y su traducción al castellano en la subtitulación

    OpenAIRE

    Seyde Abad, Patricia

    2016-01-01

    El presente Trabajo de Fin de Grado pretende hacer un análisis del argot utilizado en una parte del guión de la película escocesa Trainspotting y su traducción al castellano en la subtitulación. Se analizan las técnicas de traducción aplicadas por el traductor de la película y se propone una versión alternativa a la traducción en caso de que sea necesaria Aquest present Treball de Fi de Grau pretén fer un anàlisi del argot utilitzat en una part del guió de la pel·lícula escocesa Trainspott...

  8. Exposición de adolescentes de escuela secundaria de la Argentina y México a escenas de tabaco en películas de cine: una estimación poblacional

    OpenAIRE

    SALGADO, MARÍA V.; Adriana Pérez; Erika N. Abad Vivero; Thrasher,James F.; Sargent, James D.; Raúl Mejía

    2016-01-01

    Introducción: el tabaquismo en películas promueve el inicio de tabaquismo en adolescentes Objetivo: estimar el nivel de exposición a imágenes de tabaco contenidas en películas vistas por adolescentes de Argentina y México Métodos: Se realizó una encuesta a alumnos de primer año del secundario de Argentina y México. Se analizaron las 100 películas con mayor recaudación en cada año del periodo 2009-2013 (Argentina) y 2010-2014 (México). A cada participante se le asignó una muestra aleat...

  9. Immunomodulatory dietary polysaccharides: a systematic review of the literature

    Directory of Open Access Journals (Sweden)

    Nelson Erika D

    2010-11-01

    Full Text Available Abstract Background A large body of literature suggests that certain polysaccharides affect immune system function. Much of this literature, however, consists of in vitro studies or studies in which polysaccharides were injected. Their immunologic effects following oral administration is less clear. The purpose of this systematic review was to consolidate and evaluate the available data regarding the specific immunologic effects of dietary polysaccharides. Methods Studies were identified by conducting PubMed and Google Scholar electronic searches and through reviews of polysaccharide article bibliographies. Only articles published in English were included in this review. Two researchers reviewed data on study design, control, sample size, results, and nature of outcome measures. Subsequent searches were conducted to gather information about polysaccharide safety, structure and composition, and disposition. Results We found 62 publications reporting statistically significant effects of orally ingested glucans, pectins, heteroglycans, glucomannans, fucoidans, galactomannans, arabinogalactans and mixed polysaccharide products in rodents. Fifteen controlled human studies reported that oral glucans, arabinogalactans, heteroglycans, and fucoidans exerted significant effects. Although some studies investigated anti-inflammatory effects, most studies investigated the ability of oral polysaccharides to stimulate the immune system. These studies, as well as safety and toxicity studies, suggest that these polysaccharide products appear to be largely well-tolerated. Conclusions Taken as a whole, the oral polysaccharide literature is highly heterogenous and is not sufficient to support broad product structure/function generalizations. Numerous dietary polysaccharides, particularly glucans, appear to elicit diverse immunomodulatory effects in numerous animal tissues, including the blood, GI tract and spleen. Glucan extracts from the Trametes versicolor

  10. Efecto de la adición, tipo y concentracion de nanoarcilla sobre las propiedades mecánicas y de barrera de películas biodegradables basados en quitosano

    OpenAIRE

    2014-01-01

    La aplicación más innovadora de las películas y recubrimientos biodegradables es su empleo como matrices portadoras de distintos aditivos funcionales capaces de aumentar la seguridad, vida comercial y calidad de los alimentos. La efectividad este tipo de películas reside en el control de la migración de sus agentes activos hacia la superficie de los productos sobre los que se disponen, ayudando a la dosificación del aditivo y al mantenimiento de las concentraciones efectivas lo...

  11. Separation of Pneumcoccal Capsular Polysaccharide BY Gel Extraction

    Institute of Scientific and Technical Information of China (English)

    Xu Xiaoping; Huang Xinghua; Li Zhongqin; Chen Jiebo

    2004-01-01

    Separation of pneumcoccal capsular polysaccharide by gel was investigated in this paper. The gels used here were poly(acrylamide-co-sodium methacrylate)gels and prepared by free radical polymerization in aqueous solution. The experimental results indicated that gel extraction is a potential method to separate pneumcoccal capsular polysaccharide from its dilute solution.

  12. In vitro antioxidant activity of polysaccharide from Gardenia jasminoides ellis

    Science.gov (United States)

    Fan, Y.; Ge, Z.; Luo, A.

    2011-01-01

    A water-soluble polysaccharide, GP, was isolated from Gardenia jasminoides Ellis through hot water extraction followed by ethanol precipitation. The in vitro free radicals scavenging tests exhibited that GP has significant scavenging abilities especially for ABTS, DPPH, and hydroxyl radicals, which suggests that the polysaccharide GP is a novel antioxidant. ?? 2011 Academic Journals.

  13. Characterisation of cell wall polysaccharides in bilberries and black currants

    NARCIS (Netherlands)

    Hilz, H.

    2007-01-01

    During berry juice production, polysaccharides are released from the cell walls and cause thickening and high viscosity when the berries are mashed. Consequences are a low juice yield and a poor colour. This can be prevented by the use of enzymes that degrade these polysaccharides. To use these enzy

  14. Life cycle assessment of polysaccharide materials: a review

    NARCIS (Netherlands)

    Shen, L.; Patel, M.K.

    2008-01-01

    Apart from conventional uses of polysaccharide materials, such as food, clothing, paper packaging and construction, new polysaccharide products and materials have been developed. This paper reviews life cycle assessment (LCA) studies in order to gain insight of the environmental profiles of polysacc

  15. A novel capsular polysaccharide from Rhizobium rubi strain DSM 30149.

    Science.gov (United States)

    De Castro, Cristina; Fregolino, Eleonora; Gargiulo, Valentina; Lanzetta, Rosa; Parrilli, Michelangelo

    2008-07-07

    Rhizobium rubi, strain DSM 30149, is a Gram negative phytopathogenic bacterium which produces a linear polysaccharide with the following repeating unit: This new structure was determined by spectroscopical and chemical methods. It presents similar lipophilic features reported for another strain of R. rubi. These contrast with features already known for capsular polysaccharide species from symbiontic members of the Rhizobiaceae family, namely highly anionic polymers.

  16. Polysaccharides isolated from Acai fruit induce innate immune responses.

    Directory of Open Access Journals (Sweden)

    Jeff Holderness

    Full Text Available The Açaí (Acai fruit is a popular nutritional supplement that purportedly enhances immune system function. These anecdotal claims are supported by limited studies describing immune responses to the Acai polyphenol fraction. Previously, we characterized γδ T cell responses to both polyphenol and polysaccharide fractions from several plant-derived nutritional supplements. Similar polyphenol and polysaccharide fractions are found in Acai fruit. Thus, we hypothesized that one or both of these fractions could activate γδ T cells. Contrary to previous reports, we did not identify agonist activity in the polyphenol fraction; however, the Acai polysaccharide fraction induced robust γδ T cell stimulatory activity in human, mouse, and bovine PBMC cultures. To characterize the immune response to Acai polysaccharides, we fractionated the crude polysaccharide preparation and tested these fractions for activity in human PBMC cultures. The largest Acai polysaccharides were the most active in vitro as indicated by activation of myeloid and γδ T cells. When delivered in vivo, Acai polysaccharide induced myeloid cell recruitment and IL-12 production. These results define innate immune responses induced by the polysaccharide component of Acai and have implications for the treatment of asthma and infectious disease.

  17. Oligo- and polysaccharide synthesis by Rhizobium leguminosarum and Rhizobium meliloti.

    NARCIS (Netherlands)

    Breedveld, M.W.

    1992-01-01

    Rhizobium and Agrobacterium species are capable of synthesizing a variety of extracellular and cellular oligo- and polysaccharides. Changes in environmental conditions may all affect the composition, physical properties, and relative amounts of oligo- and polysaccharides. Interest in the field of Rh

  18. Tribological Properties of Neutral Polysaccharide Solutions under Simulated Oral Conditions

    NARCIS (Netherlands)

    Zinoviadou, K.; Janssen, A.M.; Jongh, de H.H.J.

    2008-01-01

    Predictability of the perception of foods thickened by polysaccharides is only poor. Therefore, the effect of saliva on the lubrication properties of 2 types of neutral polysaccharides, cross-linked starch and locust bean gum, was studied. Despite the similar bulk rheological behavior of the 2 polys

  19. Isolation and physical characterization of an exocellular polysaccharide

    NARCIS (Netherlands)

    Tuinier, R.; Zoon, P.; Olieman, C.; Cohen Stuart, M.A.; Fleer, G.J.; Kruif, de C.G.

    1999-01-01

    The physical properties of a polysaccharide produced by the lactic acid bacterium Lactococcus lactis subsp. cremoris strain NIZO B40 were investigated. Separation of the polysaccharide from most low molar mass compounds in the culture broth was performed by filtration processes. Residual proteins an

  20. Structural characterization and bioactivities of sulfated polysaccharide from Monostroma oxyspermum.

    Science.gov (United States)

    Seedevi, Palaniappan; Moovendhan, Meivelu; Sudharsan, Sadhasivam; Vasanthkumar, Shanmugam; Srinivasan, Alagiri; Vairamani, Shanmugam; Shanmugam, Annaian

    2015-01-01

    Sulfated polysaccharide was isolated from Monostroma oxyspermum through hot water extraction, anion-exchange and gel permeation column chromatography. The sulfated polysaccharide contained 92% of carbohydrate, 0% of protein, 7.8% of uronic acid, 22% of ash and 33% of moisture respectively. The elemental composition was analyzed using CHNS/O analyzer. The molecular weight of sulfated polysaccharide determined through PAGE was found to be as 55 kDa. Monosaccharides analysis revealed that sulfated polysaccharide was composed of rhamnose, fructose, galactose, xylose, and glucose. The structural features of sulfated polysaccharide were analyzed by NMR spectroscopy. Further the sulfated polysaccharide showed total antioxidant and DPPH free radical scavenging activity were as 66.29% at 250 μg/ml and 66.83% at 160 μg/ml respectively. The sulfated polysaccharide also showed ABTS scavenging ability and reducing power were as 83.88% at 125 μg/ml and 15.81% at 400 μg/ml respectively. The anticoagulant activity was determined for human plasma with respect to Activated Partial Thromboplastin Time (APTT) and Prothrombin Time (PT) was 20.09 IU and 1.79 IU at 25 μg/ml respectively. These results indicated that the sulfated polysaccharide from M. oxyspermum had potent antioxidant and anticoagulant activities.

  1. INTERACTION OF IONIC LIQUIDS WITH POLYSACCHARIDES

    Directory of Open Access Journals (Sweden)

    Tim Liebert

    2008-05-01

    Full Text Available The use of ionic liquids (ILs in the field of cellulose chemistry opens up a broad variety of new opportunities. Besides the regeneration of the biopolymer to fibers, films, and beads, this new class of cellulose solvents is particularly useful for the homogeneous chemical modification of the polysaccharide. In this review, the potential of ILs as a reaction medium for the homogeneous cellulose functionalization is discussed. It is shown that numerous conversions proceed very efficiently and the ILs may be recycled. But it is also demonstrated that some side reactions have to be considered.

  2. Methods of saccharification of polysaccharides in plants

    Science.gov (United States)

    Howard, John; Fake, Gina

    2014-04-29

    Saccharification of polysaccharides of plants is provided, where release of fermentable sugars from cellulose is obtained by adding plant tissue composition. Production of glucose is obtained without the need to add additional .beta.-glucosidase. Adding plant tissue composition to a process using a cellulose degrading composition to degrade cellulose results in an increase in the production of fermentable sugars compared to a process in which plant tissue composition is not added. Using plant tissue composition in a process using a cellulose degrading enzyme composition to degrade cellulose results in decrease in the amount of cellulose degrading enzyme composition or exogenously applied cellulase required to produce fermentable sugars.

  3. The Antiviral Activities and Mechanisms of Marine Polysaccharides: An Overview

    Science.gov (United States)

    Wang, Wei; Wang, Shi-Xin; Guan, Hua-Shi

    2012-01-01

    Recently, the studies on the antiviral activities of marine natural products, especially marine polysaccharides, are attracting more and more attention all over the world. Marine-derived polysaccharides and their lower molecular weight oligosaccharide derivatives have been shown to possess a variety of antiviral activities. This paper will review the recent progress in research on the antiviral activities and the mechanisms of these polysaccharides obtained from marine organisms. In particular, it will provide an update on the antiviral actions of the sulfated polysaccharides derived from marine algae including carrageenans, alginates, and fucans, relating to their structure features and the structure–activity relationships. In addition, the recent findings on the different mechanisms of antiviral actions of marine polysaccharides and their potential for therapeutic application will also be summarized in detail. PMID:23235364

  4. A simple technique for removing plant polysaccharide contaminants from DNA.

    Science.gov (United States)

    Do, N; Adams, R P

    1991-02-01

    A survey of the inhibitory effects of various plant polysaccharides on DNA restrictions (HindIII and EcoRI) revealed that neutral polysaccharides (arabino-galactan, dextran, gum guar, gum locust bean, beta-glucan, inulin, laminaran, mannan and starch) were not very inhibitory. In contrast, acidic polysaccharides (carrageenan, dextran sulfate, gum ghatti, gum karaya, pectin and xylan) were very inhibitory, even at low concentrations. The Elutip-d (RPC-5 type resin) was evaluated for removal of the inhibitory polysaccharides. Used alone or in combination with a phenol/chloroform wash, it proved effective in removing the polysaccharide so that HindIII digestion was possible, except in the cases of carrageenan and dextran sulfate. In addition, the genomic DNA extracts from live oak (Quercus virginiana) and magnolia (Magnolia grandiflora) were sufficiently purified so that the DNAs could be restricted with both EcoRI and HindIII.

  5. The Antiviral Activities and Mechanisms of Marine Polysaccharides: An Overview

    Directory of Open Access Journals (Sweden)

    Hua-Shi Guan

    2012-12-01

    Full Text Available Recently, the studies on the antiviral activities of marine natural products, especially marine polysaccharides, are attracting more and more attention all over the world. Marine-derived polysaccharides and their lower molecular weight oligosaccharide derivatives have been shown to possess a variety of antiviral activities. This paper will review the recent progress in research on the antiviral activities and the mechanisms of these polysaccharides obtained from marine organisms. In particular, it will provide an update on the antiviral actions of the sulfated polysaccharides derived from marine algae including carrageenans, alginates, and fucans, relating to their structure features and the structure–activity relationships. In addition, the recent findings on the different mechanisms of antiviral actions of marine polysaccharides and their potential for therapeutic application will also be summarized in detail.

  6. Structural Features and Healthy Properties of Polysaccharides Occurring in Mushrooms

    Directory of Open Access Journals (Sweden)

    Eva Guillamón

    2012-12-01

    Full Text Available Polysaccharides from mushrooms have attracted a great deal of attention due to the many healthy benefits they have demonstrated, such as immunomodulation, anticancer activity, prevention and treatment of cardiovascular diseases, antiviral and antimicrobial effects, among others. Isolation and purification of polysaccharides commonly involve several steps, and different techniques are actually available in order to increase extraction yield and purity. Studies have demonstrated that the molecular structure and arrangement significantly influence the biological activity; therefore, there is a wide range of analytical techniques for the elucidation of chemical structures. Different polysaccharides have been isolated from mushrooms, most of them consisting of β-linked glucans, such as lentinan from Lentinus edodes, pleuran from Pleurotus species, schizophyllan from Schizophyllum commune, calocyban from Calocybe indica, or ganoderan and ganopoly from Ganoderma lucidum. This article reviews the main methods of polysaccharide isolation and structural characterization, as well as some of the most important polysaccharides isolated from mushrooms and the healthy benefits they provide.

  7. Characterization of polysaccharides from Ganoderma spp. using saccharide mapping.

    Science.gov (United States)

    Wu, Ding-Tao; Xie, Jing; Hu, De-Jun; Zhao, Jing; Li, Shao-Ping

    2013-09-12

    Polysaccharides from Ganoderma spp. and their adulterants were firstly investigated and compared using saccharide mapping, enzymatic (endo-1,3-β-D-glucanase and pectinase) digestion followed by polysaccharide analysis using carbohydrate gel electrophoresis analysis. The results showed that both 1,3-β-D-glucosidic and 1,4-α-D-galactosiduronic linkages were existed in Lingzhi (Ganoderma lucidum and Ganoderma sinense), and the similarity of polysaccharides from G. lucidum and G. sinense was high, which may contribute to rational use of Lingzhi. Different species of Ganoderma and their adulterants can be differentiated based on the saccharide mapping, which is helpful to well understand the structural characters of polysaccharides from different species of Ganoderma and to improve the quality control of polysaccharides in Lingzhi.

  8. Sulfation of tea polysaccharides: synthesis, characterization and hypoglycemic activity.

    Science.gov (United States)

    Wang, Yuanfeng; Peng, Yonghua; Wei, Xinlin; Yang, Zhiwei; Xiao, Jianbo; Jin, Zhengyu

    2010-03-01

    Neutral polysaccharides (NTPS) and acid polysaccharides (ATPS) from tea leaves were obtained on a D315 macroporous anion-exchange resin column chromatography. NTPS and ATPS were sulfated by the pyridine-sulfonic acid method to obtain NTPS-S and ATPS-S. It was found that NTPS was easier sulfated than ATPS. There are strong characteristic absorption peaks located in 1258 cm(-1), 1146 cm(-1), 832 cm(-1) and 617 cm(-1) in the FTIR spectra of sulfated polysaccharides. Sulfation of polysaccharides also affected the endothermic and exothermic peaks via the DSC scan analysis. The appearance of exothermic peaks in both NTPS-S and ATPS-S indicated that the redox reaction might happen. The comparative study of hypoglycemic effect on mice showed that the sulfation of polysaccharides significantly improved hypoglycemic activity.

  9. Modified polysaccharides as alternative binders for foundry industry

    Directory of Open Access Journals (Sweden)

    K. Kaczmarska

    2016-10-01

    Full Text Available Polysaccharides constitute a wide group of important polymers with many commercial applications, for example food packaging, fibres, coatings, adhesives etc. This review is devoted to the presentation of polysaccharide application in foundry industry. In this paper the selected properties of foundry moulding sand and core sand containing modified polysaccharides as binders are presented according to foreign literature data. Also, author’s own research about effect of using moulding sand binder consisting of modified polysaccharide (modified starch or its composition with non-toxic synthetic polymers are discussed. Based on technologies taken under consideration in this paper, it could be concluded that polysaccharides are suitable as an alternative for use as binder in foundry moulding applications.

  10. La narración oral escénica en La contadora de películas de Hernán Rivera Letelier

    Directory of Open Access Journals (Sweden)

    Rehab Abdel Salam

    2015-02-01

    Full Text Available El trabajo presente analiza el concepto de la narración oral escénica, un término acuñado por el teórico y narrador oral Francisco Garzón Céspedes, en La contadora de películas (2009 del autor chileno Hernán Rivera Letelier (1950. La esencia de la narración oral escénica es la oralidad; es una oralidad que narra y que trasciende lo conversacional interpersonal para ser oral artística en un espacio oral escénico y con un público interlocutor. La contadora de películas es una novela autobiográfica que retrata a una protagonista  que cuenta relatos basados en las películas que ve en el cine de su pueblo a un público que, al principio se limita a los miembros de su familia y paulatinamente va abarcando a los habitantes de la oficina salitrera en que vive. Esta narradora oral aplica los principios  fundamentales de la narración oral escénica tanto en sus aspectos técnicos como temáticos. La protagonista se dispone de las cualidades personales y profesionales necesarias para un buen narrador oral escénico tales como la invención, la imaginación, la improvisación, la interacción con el público, la memoria, entre otras. A nivel técnico, aplica los principios de composición escénica; crea énfasis en su figura como narradora; maneja lo vocal con sus diferentes componentes y utiliza los diferentes tipos de lenguaje no verbal. Palabras clave: Narración oral-Narración oral escénica- Oralidad- Hernán Rivera  Letelier- Novela chilena.

  11. Research of polysaccharide complexes from asteraceae family plants

    Directory of Open Access Journals (Sweden)

    Світлана Михайлівна Марчишин

    2015-10-01

    Full Text Available Aim of research. Depth study of polysaccharides in some little-known plant species of Asteraceae family is pressing question, considering that polysaccharides are important biologically active compounds widely used in pharmaceutical and medical practice as remedies and preventive medications. The aim of research was to determinate both quantitative content and monomeric composition of polysaccharide complexes from Asteraceae family plant species – Tagetes genus, Arnica genus, and Bellis genus.Materials and methods. Determination of polysaccharides was carried out by the precipitation reaction, using 96 % ethyl alcohol P and Fehling's solution after acid hydrolysis; quantitative content of this group of compounds was determined by gravimetric analysis. On purpose to identify the monomeric composition hydrolysis under sulfuric acid conditions was conducted. Qualitative monomeric composition of polysaccharides after hydrolysis was carried out by paper chromatography method in n-Butanol – Pyridine – Distilled water P (6:4:3 system along with saccharides reference samples.Results. Polysaccharide complexes from Tagetes erecta, Tagetes patula, Tagetes tenuifolia, Arnica montana, Arnica foliosa, wild and cultivated Bellis perennis herbs were studied. Water-soluble polysaccharides and pectin fractions were isolated from studied objects; their quantitative content and monomeric composition were determined.Conclusion. The highest amount of water-soluble polysaccharides was found in cultivated Bellis perennis herb (10,13 %, the highest amount of pectin compounds – in Tagetes tenuifolia herb (13,62 %; the lowest amount of water-soluble polysaccharides and pectin compounds was found in Arnica montana herb (4,61 % and Tagetes patula herb (3,62 %, respectively. It was found that polysaccharide complexes from all studied species include glucose and arabinose

  12. Primary structure and configuration of tea polysaccharide

    Institute of Scientific and Technical Information of China (English)

    ZHOU Peng; XIE Mingyong; NIE Shaoping; WANG Xiaoru

    2004-01-01

    The monosaccharide composition of a tea polysaccharide(TGC)was determined by GC-MS method.Furthermore,the primary structure of tea polysaccharide and its configuration in the aqueous solution were investigated utilizing a combination of classical chemical methods and modern instrumental techniques including GC-MS,Proton NMR,UV and CD.The results indicate that TGC consists of 6 monosaccharides: Rha,Ara,Xyl,Glu,Man and Gal.The configuration of TGC in water solution is proposed to be an ordered helix.The possible primary structure of TGC was outlined as below: the basic structure of the main chain consists of Rha,Glu and Gal units.All three monosaccharides can potentially be connected to branch chains consisting of mainly Ara,and the linkages could be in β1 →2,β1 →3,β2→3 forms.When branch chain is absent in the basic structure of the main chain the linkage consists of only β1→3; Xyl exists at the terminal end of either the main chain or the branch chain with β1 → linkage.

  13. Microanalysis of Plant Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    Nicolai Obel; Veronika Erben; Tatjana Schwarz; Stefan Kühne; Andrea Fodor; Markus Pauly

    2009-01-01

    Oligosaccharide Mass Profiling (OLIMP) allows a fast and sensitive assessment of cell wall polymer structure when coupled with Matrix Assisted Laser Desorption Ionisation Time Of Flight Mass Spectrometry (MALDI-TOF MS). The short time required for sample preparation and analysis makes possible the study of a wide range of plant organs, revealing a high degree of heterogeneity in the substitution pattern of wall polymers such as the cross-linking glycan xyloglucan and the pectic polysaccharide homogalacturonan. The high sensitivity of MALDI-TOF allows the use of small amounts of samples, thus making it possible to investigate the wall structure of single cell types when material is collected by such methods as laser micro-dissection. As an example, the analysis of the xyloglucan structure in the leaf cell types outer epidermis layer, entire epidermis cell layer, palisade mesophyll cells, and vascular bundles were investigated. OLIMP is amenable to in situ wall analysis, where wall polymers are analyzed on unprepared plant tissue itself without first iso-lating cell walls. In addition, OLIMP enables analysis of wall polymers in Golgi-enriched fractions, the location of nascent matrix polysaccharide biosynthesis, enabling separation of the processes of wall biosynthesis versus post-deposition apo-plastic metabolism. These new tools will make possible a semi-quantitative analysis of the cell wall at an unprecedented level.

  14. Bacterial Extracellular Polysaccharides Involved in Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Elena P. Ivanova

    2009-07-01

    Full Text Available Extracellular polymeric substances (EPS produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed.

  15. ¿Qué es la verdad? ¿Qué es la ficción? Memorias movilizadas en la película Perro come perro

    Directory of Open Access Journals (Sweden)

    Paola Clavijo González

    2017-01-01

    Full Text Available Este artículo se propone explorar cuáles fueron las memorias movilizadas sobre el fenómeno de la violencia contemporánea en la película colombiana Perro come perro, del director caleño Carlos Moreno, estrenada en el 2008. A partir de los aportes teóricos de Pécaut, Todorov y Halbwachs, se analiza una de las películas más discutidas mediáticamente en el país, entre los años 2003 y 2013. La memoria es abordada como un hecho social colectivo que expresa las elucubraciones que han realizado diferentes grupos sobre situaciones que les han afectado, como se observa en el intento reciente del cine colombiano de ficción por reelaborar este fenómeno. El cine, en cuanto producto cultural, constituye un vehículo de la memoria al construir y comunicar relatos sobre el pasado vivido. Este ejercicio de rememoración está atravesado por los usos del pasado en el presente, a través de una selección consciente e inconsciente de qué y cómo recordar. En vista de que la ficción es considerada lenguaje de la memoria, resulta imperativo entender cómo los grupos detrás de las producciones cinematográficas ponen en escena sentidos, tramas que consideran legítimas y verdaderas para ser contadas, creando narrativas sobre las realidades que experimentan. Al ser la unidad de análisis un producto cinematográfico, se adopta una metodología interdisciplinar, compuesta por el modelo actancial de Greimas y Martín Serrano, y un modelo propio inspirado en Goffman sobre los personajes e identificadores, a partir de los cuales se describen los marcos sociales evocados en la película; se identifican las identidades, objetos y lugares; se elaboran sus programas narrativos y se establecen los tipos de memorias movilizadas. Entre los hallazgos más interesantes está la experiencia mágico-religiosa como uno de los hilos narrativos fundamentales de la historia. La película apela a una de las metáforas emblemáticas de la violencia en Colombia, en la que

  16. Caracteritzación de una sala de cine para la proyección de películas en 3D

    OpenAIRE

    Álvarez Borrell, Cristina

    2015-01-01

    El Trabajo se centra en caracterizar la sala comercial de proyección de películas en 3D con la pantalla más grande de Catalunya. Nos proponemos caracterizar geométricamente la sala y describir el sistema de proyección que utiliza. Para relacionarlo con la optometría se definirá un observador promedio, del cual tomaremos su rango de la Zona de Visión Binocular Simple y Nítida para obtener, mediante los criterios de Sheard y Pércival, la zona de visión cómoda, y extrapolarlo a la separación ent...

  17. Los arquetipos de género en las películas infantiles. Una propuesta de taller para el alumnado de Educación Primaria

    OpenAIRE

    Gómez Beltrán, Iván

    2013-01-01

    Debido al avance teórico de los Estudios de Género, es necesario que se replanteen los procesos pedagógicos por los cuales se transmite a la infancia, a través de entretenimientos considerados fútiles, una dañina ideología patriarcal desde los primeros años de vida. Por ello, con este trabajo se propone un modelo de taller para alumnado de Educación Primaria de entre 10 y 12 años. Con la colaboración de los y las tutoras legales y a través del análisis de tres películas de la compañía Disney ...

  18. Cine y memoria cultural: la ilusión del multiculturalismo a partir de dos películas mexicanas de animación

    Directory of Open Access Journals (Sweden)

    Julián Woodside

    2012-01-01

    Full Text Available Este texto aborda cómo es que en México se ha construido la ilusión de un multiculturalismo mediante un "racismo asimilacionista" apoyado en la idea reduccionista de lo "mexicano" como la mezcla de lo "hispano" y lo "indígena". A partir de un análisis semiohistórico de dos películas mexicanas de animación infantil, "La leyenda de la Nahuala" (2007 de Ricardo Arnaiz y "Héroes Verdaderos. Episodio: Independencia" (2010 de Carlos Kuri; así como una discusión sobre la construcción de narrativas oficiales en México, se identifican una serie de motivos y argumentos que reflejan lo que histórica y mediáticamente se ha definido como lo "mexicano", contemplando el hecho de que ambas películas reproducen ideas que generarán fuertes improntas en un público infantil, perpetuando dicha ilusión de multiculturalismo. Finalmente, este análisis demuestra cómo aún cuando a partir de la década de los setenta el Estado mexicano buscó avanzar hacia la plurietnicidad y el multiculturalismo, la realidad es que en México se sigue representando a lo "indígena" como lo pasivo y tradicional y a lo "europeo" como lo activo y moderno, limitando la posibilidad de construir narrativas a partir de voces e identidades indígenas sin que connoten mediáticamente cierto desaceleramiento u obsolescencia.

  19. Los protagonistas de las películas colombianas 1990-2003.The stars of the Colombian films 1990-2003

    Directory of Open Access Journals (Sweden)

    Jerónimo León Rivera Betancur

    Full Text Available ResumenEl cine colombiano es el objeto de estudio de este artículo, que parte de los resultados de la investigación “Personajes, acciones y escenarios en el cine colombiano de 1970-2005”, realizada en la Universidad de Medellín (Colombia entre 2005 y 2007. Se trata de un artículo de revisión en el que se hace un análisis narrativo de la representación de personajes protagónicos en las películas colombianas de la década de 1990 hasta 2003 (año de la puesta en marcha de la ley del cine en Colombia. Se abordan algunas películas de la muestra y en cada una se hace un análisis de los personajes más representativos.AbstractThe Colombian cinema is the object of study of this article, which departs from the results of the research "Prominent figures, actions and scenes in the Colombian cinema of 1970-2005 ", realized in the University of Medellin (Colombia from 2005 to 2007. It is an article of review a narrative analysis of the representation of leading prominent figures in the Colombian movies of the decade of 1990 until 2003 (year of the putting in march of the law of the cinema in Colombia. Some movies of the sample are approached and in each one there is done an analysis of the most representative prominent figures.

  20. Intestinal GPS: bile and bicarbonate control cyclic di-GMP to provide Vibrio cholerae spatial cues within the small intestine

    OpenAIRE

    Koestler, Benjamin J.; Waters, Christopher M.

    2015-01-01

    The second messenger cyclic di-GMP (c-di-GMP) regulates numerous phenotypes in response to environmental stimuli to enable bacteria to transition between different lifestyles. Here we discuss our recent findings that the human pathogen Vibrio cholerae recognizes 2 host-specific signals, bile and bicarbonate, to regulate intracellular c-di-GMP. We have demonstrated that bile acids increase intracellular c-di-GMP to promote biofilm formation. We have also shown that this bile-mediated increase ...

  1. The immunostimulating role of lichen polysaccharides: a review.

    Science.gov (United States)

    Shrestha, Gajendra; St Clair, Larry L; O'Neill, Kim L

    2015-03-01

    The immune system has capacity to suppress the development or progression of various malignancies including cancer. Research on the immunomodulating properties of polysaccharides obtained from plants, microorganisms, marine organisms, and fungi is growing rapidly. Among the various potential sources, lichens, symbiotic systems involving a fungus and an alga and/or a cyanobacterium, show promise as a potential source of immunomodulating compounds. It is well known that lichens produce an abundance of structurally diverse polysaccharides. However, only a limited number of studies have explored the immunostimulating properties of lichen polysaccharides. Published studies have shown that some lichen polysaccharides enhance production of nitrous oxide (NO) by macrophages and also alter the production levels of various proinflammatory and antiinflammatory cytokines (IL-10, IL-12, IL-1β, TNF-α, and IFN-α/β) by macrophages and dendritic cells. Although there are only a limited number of studies examining the role of lichen polysaccharides, all results suggest that lichen polysaccharides can induce immunomodulatory responses in macrophages and dendritic cells. Thus, a detailed evaluation of immunomodulatory capacity of lichen polysaccharides could provide a unique opportunity for the discovery of novel therapeutic agents.

  2. New polysaccharide-based polymer electrolytes; Nouveaux electrolytes polymeres a base de polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Velasquez-Morales, P.; Le Nest, J.F.; Gandini, A. [Ecole Francaise de Papeterie et des Industries Graphique, 38 - Saint Martin d`Heres (France)

    1996-12-31

    Polysaccharides like cellulose and chitosan are known for their filmic properties. This paper concerns the synthesis and the study of chitosan-based polymer electrolytes. A preliminary work concerns the study of glucosamine reactivity. The poly-condensation of chitosan ethers (obtained by reaction with ethylene oxide or propylene oxide) with bifunctional and monofunctional oligo-ethers leads to the formation of thin lattices (10 {mu}m) having excellent mechanical properties. The presence of grafted polyether chains along the polysaccharide skeleton allows to modify the vitreous transition temperature and the molecular disorder of the system. Two type of polymer electrolytes have been synthesized: electrolytes carrying a dissolved alkaline metal salt and ionomers. The analysis of their thermal, dynamical mechanical, nuclear magnetic relaxation, electrical, and electrochemical properties shows that this new class of polymer electrolytes has the same performances as ethylene poly-oxide based amorphous lattices plus the advantage of having good filmic properties. Abstract only. (J.S.)

  3. Construction of Vector Harboring Pectin Lyase C Gene and Its Expression in E. coli%果胶裂解酶基因PelC表达载体的构建及原核表达分析

    Institute of Scientific and Technical Information of China (English)

    邓伟科; 郭安平; 刘恩平; 王炎松; 郭运玲; 孔华; 阳辛凤; 贺立卡

    2009-01-01

    A complete open reading frame of pectin lyase C (PelC) cloned from a pectinase-producing strain BTC105 isolated and collected in the laboratory was constructed on a plasmid pET28a and transferred into E. coli BL21 (DE3) to carry out fuse expression; and flask shaking fermented in LB (Luria-Bertani) , induced with 1 mmol/L IPTG (iso-propyl β-D-1-thiogalactopyranoside). The results showed that the recombinant plasmid pET28a-pelC was constructed successfully and PelC has mainly expressed in E. coli BL21 (DE3). The optimal pH of the enzyme was 5.4, optimal temperature at 50℃, Ca~(2+) stimulated strongly on the enzyme activity, however, Cu~(2+) completely inhibited the activity.%从实验室分离保存的1株产果胶酶的菌株(BTC105)中克隆果胶裂解酶基因(PelC)完整开放阅读框,通过载体构建,将目的基因连接到表达载体pET28a上,转化大肠埃希菌BL21(DE3)进行融合表达,在LB(Luria-Bertani)中进行摇瓶发酵,1 mmol/L IPTG(异丙基-β-D-硫代半乳糖苷)诱导.结果表明,构建了表达载体pET28a-pelC,果胶裂解酶主要在胞内表达,酶活最适pH为5.4,最适温度为50℃,Ca~(2+)对酶活促进作用最为明显,Cu~(2+)完全抑制了酶的活性.

  4. Composite polysaccharide fibers prepared by electrospinning and coating.

    Science.gov (United States)

    Maeda, N; Miao, J; Simmons, T J; Dordick, J S; Linhardt, R J

    2014-02-15

    Composite polysaccharide fibers composed two oppositely charged natural polysaccharides, chitosan and hyaluronic acid, were prepared by electrospinning and subsequent coating. The fiber size distribution was characterized by scanning electron microscopy. Chitosan/hyaluronic acid composite fibers were stable in water but showed controlled release of hyaluronic acid into phosphate buffered saline, and the presence of 3-wt% hyaluronic acid coating improved the swelling ratio to 30%. The resulting composite polysaccharide fibers have a number of potential biomedical applications in wound healing applications and in drug delivery systems.

  5. Navicula sp. Sulfated Polysaccharide Gels Induced by Fe(III): Rheology and Microstructure

    OpenAIRE

    2016-01-01

    A sulfated polysaccharide extracted from Navicula sp. presented a yield of 4.4 (% w/w dry biomass basis). Analysis of the polysaccharide using gas chromatography showed that this polysaccharide contained glucose (29%), galactose (21%), rhamnose (10%), xylose (5%) and mannose (4%). This polysaccharide presented an average molecular weight of 107 kDa. Scanning electron microscopy (SEM) micrographs showed that the lyophilized Navicula sp. polysaccharide is an amorphous solid with particles of ir...

  6. Use of paramagnetic chelated metal derivatives of polysaccharides and spin-labeled polysaccharides as contrast agents in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bligh, S.W.; Harding, C.T.; Sadler, P.J.; Bulman, R.A.; Bydder, G.M.; Pennock, J.M.; Kelly, J.D.; Latham, I.A.; Marriott, J.A. (Department of Chemistry, Birkbeck College, London (England))

    1991-02-01

    Soluble and insoluble polysaccharides were derivatized with diethylenetriaminepentaacetic acid (DTPA) and/or spin-labeled with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO). Polysaccharides derivatized with DTPA were prepared via cyanogen bromide activation, coupling to a diamine linker, and to DTPA anhydride. Spin-labeled polysaccharides were also prepared via cyanogen bromide activation. The extent of derivatization for dextran (18 kDa) was about 120 glucose units per DTPA, and for cellulose and starch about 15-30 units per DTPA. For spin-labeled polysaccharides, the average loading ranged from 1 nitroxide per 16 glucose units for starch to 181 for dextran (82 kDa). These derivatized paramagnetic polysaccharides were shown to be more effective relaxants than the small paramagnetic molecules alone. Both soluble and insoluble polysaccharide-linker-DTPA-Gd(3) complexes were effectively cleared from the body (rats) after oral administration. After intravenous administration, the biodistribution of dextran-linker-DTPA-Gd(3) complexes differed significantly from that of GdDTPA. Reduction of the nitroxide by ascorbic acid was retarded in the polysaccharide derivatives, particularly in starch derivatized with both nitroxide and linker-DTPA-Cu(2). These agents showed contrast enhancement in the gastrointestinal tract of rabbits.

  7. An Acidic Polysaccharide from Tribulus terrestris

    Institute of Scientific and Technical Information of China (English)

    HaiShengCHEN; WingNangLEUNG; 等

    2002-01-01

    An aqueous acidic polysaccharide, named rhamnogalacturonan (designated as TIP-D2) was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration.TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose,fucose,mannose,xylose and glucose in a ratio of 71.4:13.5:5.6:4.9:3.1:1.9:1.9:1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccaride with the connection of α-(1-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and determination of 1H,13C-NMR spectra.

  8. An Acidic Polysaccharide from Tribulus terrestris

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    An aqucous acidic polysaccharide, named rhamnogalacturonan (designated as TTP-D2)was isolated from Tribulus terrestris L by means of DEAE-cellulose chromatography and gel filtration. The molecular mass of TTP-D2 was estimated to be 26 KDa by gel filtration. TTP-D2 is composed of galacturonic acid, rhamnose, arabinose, galactose, fucose, mannosc, xylose and glucose in a ratio of 71.4: 13.5: 5.6: 4.9: 3.1: 1.9: 1.9: 1.0. The main chain structure of TTP-D2 was elucidated as an acidic hetero-polysaccharidc with the connection of α-(l-4) galacturonic acid with α-(1-3) rhamnose by GC analysis of partially hydrolyzed products and the determination of 1H, 13C-NMR spectra.

  9. NMR studies of polysaccharides from brown seaweeds

    Energy Technology Data Exchange (ETDEWEB)

    Noseda, M.D.; Tisher, C.A.; Gorin, P.A.J.; Duarte, M.E.R. [Parana Univ., Curitiba, PR (Brazil). Dept. de Bioquimica; Cerezo, A.S. [Buenos Aires Univ. Nacional (Argentina). Dept. de Quimica Organica

    1997-12-31

    Alginic acid is the major intercellular polysaccharide serving as matrix in the brown algae and is comprised of an unbranched chain of (1->4)-linked {beta}-D-mannuronic acid (M) and {alpha}-L-guluronic acid (G), arranged in a blockwise fashion. The composition of the monomer residues and the block structure varies depending on the source of the polymer. The selective binding of cations to alginate accounts for its ability to form gels, which is dependent on the number and lenght of the G-blocks. They are widely used industrially for their ability to retain water, and for their gelling, viscosifying and stabilizing properties (Smidsrod and draget, 1996). In this study, alginate composition and block structure in Sargassum stenophyllum has been determined by chemical methods and NMR spectroscopic analysis. (author) 4 refs., 3 figs.

  10. Enzymatic Modification of Plant Cell Wall Polysaccharides

    DEFF Research Database (Denmark)

    Øbro, Jens; Hayashi, Takahisa; Mikkelsen, Jørn Dalgaard

    2011-01-01

    fibres, hydrocolloids, paper,textile, animal feeds or biofuels. Classical microbial-based fermentation systems could in the future face serious competition from plant-based expression systems for enzyme production. Plant expressed enzymes can either be targeted to specific cellular compartments......Plant cell walls are intricate structures with remarkable properties, widely used in almost every aspect of our life. Cell walls consist largely of complex polysaccharides and there is often a need for chemical and biochemical processing before industrial use. There is an increasing demand...... for sustainable processes that replace chemical treatments with white biotechnology. Plants can contribute significantly to this sustainable process by producing plant or microbialenzymes in planta that are necessary for plant cell wall modification or total degradation. This will give rise to superior food...

  11. Cyclic di-GMP riboswitch-regulated type IV pili contribute to aggregation of Clostridium difficile.

    Science.gov (United States)

    Bordeleau, Eric; Purcell, Erin B; Lafontaine, Daniel A; Fortier, Louis-Charles; Tamayo, Rita; Burrus, Vincent

    2015-03-01

    Clostridium difficile is an anaerobic Gram-positive bacterium that causes intestinal infections with symptoms ranging from mild diarrhea to fulminant colitis. Cyclic diguanosine monophosphate (c-di-GMP) is a bacterial second messenger that typically regulates the switch from motile, free-living to sessile and multicellular behaviors in Gram-negative bacteria. Increased intracellular c-di-GMP concentration in C. difficile was recently shown to reduce flagellar motility and to increase cell aggregation. In this work, we investigated the role of the primary type IV pilus (T4P) locus in c-di-GMP-dependent cell aggregation. Inactivation of two T4P genes, pilA1 (CD3513) and pilB1 (CD3512), abolished pilus formation and significantly reduced cell aggregation under high c-di-GMP conditions. pilA1 is preceded by a putative c-di-GMP riboswitch, predicted to be transcriptionally active upon c-di-GMP binding. Consistent with our prediction, high intracellular c-di-GMP concentration increased transcript levels of T4P genes. In addition, single-round in vitro transcription assays confirmed that transcription downstream of the predicted transcription terminator was dose dependent and specific to c-di-GMP binding to the riboswitch aptamer. These results support a model in which T4P gene transcription is upregulated by c-di-GMP as a result of its binding to an upstream transcriptionally activating riboswitch, promoting cell aggregation in C. difficile.

  12. Nucleotide binding by the widespread high-affinity cyclic di-GMP receptor MshEN domain.

    Science.gov (United States)

    Wang, Yu-Chuan; Chin, Ko-Hsin; Tu, Zhi-Le; He, Jin; Jones, Christopher J; Sanchez, David Zamorano; Yildiz, Fitnat H; Galperin, Michael Y; Chou, Shan-Ho

    2016-01-01

    C-di-GMP is a bacterial second messenger regulating various cellular functions. Many bacteria contain c-di-GMP-metabolizing enzymes but lack known c-di-GMP receptors. Recently, two MshE-type ATPases associated with bacterial type II secretion system and type IV pilus formation were shown to specifically bind c-di-GMP. Here we report crystal structure of the MshE N-terminal domain (MshEN1-145) from Vibrio cholerae in complex with c-di-GMP at a 1.37 Å resolution. This structure reveals a unique c-di-GMP-binding mode, featuring a tandem array of two highly conserved binding motifs, each comprising a 24-residue sequence RLGxx(L/V/I)(L/V/I)xxG(L/V/I)(L/V/I)xxxxLxxxLxxQ that binds half of the c-di-GMP molecule, primarily through hydrophobic interactions. Mutating these highly conserved residues markedly reduces c-di-GMP binding and biofilm formation by V. cholerae. This c-di-GMP-binding motif is present in diverse bacterial proteins exhibiting binding affinities ranging from 0.5 μM to as low as 14 nM. The MshEN domain contains the longest nucleotide-binding motif reported to date.

  13. Utilization of polysaccharides by radiation processing

    Energy Technology Data Exchange (ETDEWEB)

    Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Radiation treatment has been applied for improvement or pasteurization of agro-resources to recycle the resources and to reduce the pollution of environment. By using the radiation effect for pasteurization, upgrading of cellulosic wastes of oil palm to animal feeds and mushroom has been studied under the bilateral research cooperation between JAERI and MINT (Malaysian Institute for Nuclear Technology Research). The necessary dose for pasteurization of oil palm empty fruit bunch (EFB), which is a main cellulosic by-product of palm oil industry, was determined as 10 kGy. After pasteurization, the EFB substrate was inoculated with Pleurotus sajor-caju and fermented for 1 month. The digestibility and nutritional value of fermented products were evaluated as ruminant feeds and the mushroom can be produced as by-product. For the improvement of resources, radiation effects on polysaccharides such as chitosan, sodium alginate, carrageenan, cellulose, pectin have been investigated to induce the biological activities. These carbohydrates were easily degraded by irradiation and induced various kinds of biological activities. The anti-bacterial activity and elicitor activity of chitosan were induced by irradiation. The induction of phytoalexins was also observed by irradiated pectin but the higher elicitor activity for pisatin was obtained by chitosan than pectin. For the plant growth promotion, alginate derived from brown marine algae, chitosan and ligno-cellulosic extracts show a strong activity. carrageenan derived from red marine algae can promote growth of rice and the highest effect was obtained with kappa carrageenan irradiated at 100 kGy. Furthermore, some radiation degraded polysaccharides suppressed the damage of environmental stress on plants. (author)

  14. Synbiotic matrices derived from plant oligosaccharides and polysaccharides

    Science.gov (United States)

    A porous synbiotic matrix was prepared by lyophilization of alginate and pectin or fructan oligosaccharides and polysaccharides cross-linked with calcium. These synbiotic matrices were excellent physical structures to support the growth of Lactobacillus acidophilus (1426) and Lactobacillus reuteri (...

  15. Degradation studies on Escherichia coli capsular polysaccharides by bacteriophages.

    Science.gov (United States)

    Nimmich, W

    1997-08-01

    The serologically and structurally related Eschrichia coli capsular polysaccharides (K antigens) K13, K20, and K23 were found to be depolymerized by the bacteriophages phi K13 and phi K20 to almost similar oligomer profiles as shown by polyacrylamide gel electrophoresis. The phage-polysaccharide interactions were followed by an increase of reducing 2-keto-3-deoxyoctulosonic acid due to a phage-associated glycanase that catalyzed the hydrolytic cleavage of common beta-ketopyranosidic 2-keto-3-deoxyoctulosonic acid linkages. The related E. coli K antigens K18, K22, and K100 as well as the Haemophilus influenzae type b capsular polysaccharide were degraded by bacteriophage phi K100 with different efficacy. It is suggested that phi K100 enzymatically cleaves ribitol-5-phosphate bonds as the only structural feature present in all the polysaccharides investigated.

  16. Radiation processed hydrogel of poly (vinyl alcohol) with biodegradable polysaccharides.

    Science.gov (United States)

    Chowdhury, M N K; Alam, A K M M; Dafader, N C; Haque, M E; Akhtar, F; Ahmed, M U; Rashid, H; Begum, R

    2006-01-01

    Poly(vinyl alcohol) (PVA) can be modified to polymer hydrogels by radiation crosslinking and can be used in different biomedical applications. A study was done on the optimization of ingredients concentration for preparing good quality PVA hydrogels with natural polysaccharides. The synthesized hydrogels were also characterized by measuring the different physical properties e.g. gel fraction, swelling and absorption rate. Besides these, sterility test were also performed. Good quality hydrogels were obtained from PVA and natural polysaccharides solutions with 27 kGy radiation dose. There is an influence of natural polysaccharides on the gel fraction of hydrogel. The increase in the amount of polysaccharide causes a decrease in gel fraction that is decrease in the crosslinking density of PVA hydrogel network. The prepared hydrogels were found to be sterile.

  17. Detection of Inulin, a Prebiotic Polysaccharide, in Maple Syrup.

    Science.gov (United States)

    Sun, Jiadong; Ma, Hang; Seeram, Navindra P; Rowley, David C

    2016-09-28

    Maple syrup is a widely consumed plant-derived natural sweetener produced by concentrating xylem sap collected from certain maple (Acer) species. During thermal evaporation of water, natural phytochemical components are concentrated in maple syrup. The polymeric components from maple syrup were isolated by ethanol precipitation, dialysis, and anion exchange chromatography and structurally characterized by glycosyl composition analysis, glycosyl linkage analysis, and nuclear magnetic resonance spectroscopy. Among the maple syrup polysaccharides, one neutral polysaccharide was characterized as inulin with a broad molecular weight distribution, representing the first isolation of this prebiotic carbohydrate from a xylem sap. In addition, two acidic polysaccharides with structural similarity were identified as arabinogalactans derived from rhamnogalacturonan type I pectic polysaccharides.

  18. Extraction and antioxidant activity of polysaccharides from Rana chensinensis skin.

    Science.gov (United States)

    Wang, Zhanyong; Zhao, Yuanyuan; Su, Tingting

    2015-01-22

    The extraction process of polysaccharides from Rana chensinensis skin was optimized by using a Box-Behnken design. The optimum extraction conditions were as follows: extraction time, 4.96h; extraction temperature, 100°C; ratio of water to raw material, 60; and extraction frequency, 1. Under these conditions, the experimental polysaccharide yield was 2.03±0.14%, which agreed with the predicted yield. The purified polysaccharide RCSP II was successfully obtained by diethylaminoethanol-Sepharose and Sepharose CL-6B column chromatography. In vitro experiments showed that RCSP II exhibited a strong scavenging activity against superoxide anion and 1,1-diphenyl-2-picrylhydrazyl radicals but a weak scavenging activity against hydroxyl radicals. RCSP II also showed a strong reducing capacity. Thus, this polysaccharide can be used as a natural antioxidant in functional foods or medicines.

  19. Comparison of Polysaccharides from Two Species of Ganoderma

    Directory of Open Access Journals (Sweden)

    Yu-Ping Tang

    2012-01-01

    Full Text Available Ganoderma lucidum and Ganoderma sinense, known as Lingzhi in Chinese, are commonly used Chinese medicines with excellent beneficial health effects. Triterpenes and polysaccharides are usually considered as their main active components. However, the content of triterpenes differs significantly between the two species of Ganoderma. To date, a careful comparison of polysaccharides from the two species of Ganoderma has not been performed. In this study, polysaccharides from fruiting bodies of two species of Lingzhi collected from different regions of China were analyzed and compared based on HPSEC-ELSD and HPSEC-MALLS-RI analyses, as well as enzymatic digestion and HPTLC of acid hydrolysates. The results indicated that both the HPSEC-ELSD profiles and the molecular weights of the polysaccharides were similar. Enzymatic digestion showed that polyshaccharides from all samples of Lingzhi could be hydrolyzed by pectinase and dextranase. HPTLC profiles of their TFA hydrolysates colored with different reagents and their monosaccharides composition were also similar.

  20. Composite polysaccharide fibers prepared by electrospinning and coating

    OpenAIRE

    2013-01-01

    Composite polysaccharide fibers composed two oppositely charged natural polysaccharides, chitosan and hyaluronic acid, were prepared by electrospinning and subsequent coating The fiber size distribution was characterized by scanning electron microscopy. Chitosan/hyaluronic acid composite fibers were stable in water but showed controlled release of hyaluronic acid into phosphate buffered saline, and the presence of 3-wt% hyaluronic acid coating improved the swelling ratio to 30%. The resulting...

  1. Identification of a capsular polysaccharide from Moraxella bovis.

    Science.gov (United States)

    Wilson, Jennifer C; Hitchen, Paul G; Frank, Martin; Peak, Ian R; Collins, Patrick M; Morris, Howard R; Dell, Anne; Grice, I Darren

    2005-03-21

    The bacterium Moraxella bovis is the causative agent of an economically important disease of cattle: Infectious Bovine Keratoconjunctivitis (IBK), otherwise known as pinkeye. Little is known regarding the structure of the carbohydrates produced by M. bovis. The structure of a capsular polysaccharide from M. bovis (strain Mb25) has been determined using NMR and MS analysis. From these data it is concluded that the polysaccharide is composed of the unmodified chondroitin disaccharide repeat unit.

  2. Characterization of Polysaccharide by HPLC: Extraction and Anticancer Effects

    OpenAIRE

    Liming Gao; Ya Di; Jiandong Wu; Ming Shi; Fulu Zheng

    2014-01-01

    Cervical cancer is a serious health hazard for women’s reproductive system cancer; the method of treatment for cervical cancer is still in surgery, chemotherapy, and radiotherapy as the basic means, but with many complications. The effects of natural medicines for cervical cancer are increasingly becoming the focus of people’s attentions. By studying the polysaccharide of cervical cancer in mice, we found that shark cartilage polysaccharide can increase the serum levels of T-SOD and GSH and d...

  3. Characterization of active polysaccharides of HemoHIM

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang Sun; Shin, Myeong Suk; Bae, Beom Seon; Hwang, Yong Cheol [Kyonggi University, Suwon (Korea, Republic of); Ryu, Kwang Won [Chungju University, Chungju (Korea, Republic of)

    2007-07-15

    In this study, we aimed to elucidate the detailed structure and active moiety of polysaccharide, one of the active constituents of immune and hematopoietic modulating activities of HemoHIM. We first isolated the polysaccharide fractions from the hot water extracts of the each ingredient herbs (A. gigas, P. janonica, C. officinale) of HemoHIM and their mixture. These polysaccharides were composed of neutral (85.32-92.73%) and acidic (4.25-7.88%) saccharides, proteins (0.16-4.02%), and polyphenols (2.09-5.37%). The hydrolytic analysis of polysaccharide fractions showed that they commonly showed higher arabinose, galactose, and galacturonic acid contents. These result suggested that these polysaccharides may have higher contents of rhamnogalacturonan among pectic substances and the main active moiety is composed of polysaccharides. The anion exchange chromatography of HemoHIM and each ingredient herb extract using DEAE-Sepharose FF (Cl- form) column resulted in 1 non-adsorption and 8 adsorption fractions. The analysis of immune activity (lymphocyte proliferation) on these fractions showed that the fractions obtained by higher salt concentration carried the higher activity, but all fractions showed considerable immune activity

  4. Marine derived polysaccharides for biomedical applications: chemical modification approaches.

    Science.gov (United States)

    d'Ayala, Giovanna Gomez; Malinconico, Mario; Laurienzo, Paola

    2008-09-03

    Polysaccharide-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gelentrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form hydrogels. Most of the polysaccharides used derive from natural sources; particularly, alginate and chitin, two polysaccharides which have an extensive history of use in medicine, pharmacy and basic sciences, and can be easily extracted from marine plants (algae kelp) and crab shells, respectively. The recent rediscovery of poly-saccharidebased materials is also attributable to new synthetic routes for their chemical modification, with the aim of promoting new biological activities and/or to modify the final properties of the biomaterials for specific purposes. These synthetic strategies also involve the combination of polysaccharides with other polymers. A review of the more recent research in the field of chemical modification of alginate, chitin and its derivative chitosan is presented. Moreover, we report as case studies the results of our recent work concerning various different approaches and applications of polysaccharide-based biomaterials, such as the realization of novel composites based on calcium sulphate blended with alginate and with a chemically modified chitosan, the synthesis of novel alginate-poly(ethylene glycol) copolymers and the development of a family of materials based on alginate and acrylic polymers of potential interest as drug delivery systems.

  5. Marine Derived Polysaccharides for Biomedical Applications: Chemical Modification Approaches

    Directory of Open Access Journals (Sweden)

    Paola Laurienzo

    2008-09-01

    Full Text Available Polysaccharide-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gelentrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form hydrogels. Most of the polysaccharides used derive from natural sources; particularly, alginate and chitin, two polysaccharides which have an extensive history of use in medicine, pharmacy and basic sciences, and can be easily extracted from marine plants (algae kelp and crab shells, respectively. The recent rediscovery of poly-saccharidebased materials is also attributable to new synthetic routes for their chemical modification, with the aim of promoting new biological activities and/or to modify the final properties of the biomaterials for specific purposes. These synthetic strategies also involve the combination of polysaccharides with other polymers. A review of the more recent research in the field of chemical modification of alginate, chitin and its derivative chitosan is presented. Moreover, we report as case studies the results of our recent work concerning various different approaches and applications of polysaccharide-based biomaterials, such as the realization of novel composites based on calcium sulphate blended with alginate and with a chemically modified chitosan, the synthesis of novel alginate-poly(ethylene glycol copolymers and the development of a family of materials based on alginate and acrylic polymers of potential interest as drug delivery systems.

  6. Oral versus postingestive origin of polysaccharide appetite in the rat.

    Science.gov (United States)

    Sclafani, A; Nissenbaum, J W

    1987-01-01

    Previous studies have revealed that rats consume substantial amounts of polysaccharide solutions, even if the solutions are made bitter with the addition of sucrose octa acetate (SOA). The present experiment used the gastric sham-feeding preparation to determine if it is the orosensory or postingestive properties of polysaccharides that motivate rats to consume polysaccharide (Polycose) solutions. In Experiment 1, food deprived rats sham fed less of a 0.05% SOA + 32% Polycose solution than they did of a 32% glucose solution, but their SOA-Polycose intake was still considerable (44 ml/hr). The same rats refused to sham feed SOA-gum and SOA-sugar solutions that were similar to the SOA-Polycose solution in bitter taste, viscosity and free sugar content. In Experiment 2, rats sham fed as much of a 32% Polycose solution as they did of a 32% sucrose solution. Despite the gastric fistula, some of the ingested Polycose was absorbed as evidenced by an increase in the rats' blood glucose levels. The addition of acarbose, a drug that inhibits polysaccharide digestion, to the Polycose solution blocked the increase in blood glucose, but did not reduce the rats' sham feeding of the solution. These findings indicate that it is the orosensory (presumably taste) properties of polysaccharide solutions, not their postingestive effects, that initially attract rats to the solutions. The results question the assumption that polysaccharides are "tasteless" to animals.

  7. Correlation Between Chain Architecture and Hydration Water Structure in Polysaccharides.

    Science.gov (United States)

    Grossutti, Michael; Dutcher, John R

    2016-03-14

    The physical properties of confined water can differ dramatically from those of bulk water. Hydration water associated with polysaccharides provides a particularly interesting example of confined water, because differences in polysaccharide structure provide different spatially confined environments for water sorption. We have used attenuated total reflection infrared (ATR-IR) spectroscopy to investigate the structure of hydration water in films of three different polysaccharides under controlled relative humidity (RH) conditions. We compare the results obtained for films of highly branched, dendrimer-like phytoglycogen nanoparticles to those obtained for two unbranched polysaccharides, hyaluronic acid (HA), and chitosan. We find similarities between the water structuring in the two linear polysaccharides and significant differences for phytoglycogen. In particular, the results suggest that the high degree of branching in phytoglycogen leads to a much more well-ordered water structure (low density, high connectivity network water), indicating the strong influence of chain architecture on the structuring of water. These measurements provide unique insight into the relationship between the structure and hydration of polysaccharides, which is important for understanding and exploiting these sustainable nanomaterials in a wide range of applications.

  8. Liposome-Based Delivery Systems in Plant Polysaccharides

    Directory of Open Access Journals (Sweden)

    Meiwan Chen

    2012-01-01

    Full Text Available Plant polysaccharides consist of many monosaccharide by α- or β-glycosidic bond which can be extracted by the water, alcohol, lipophile liquid from a variety of plants including Cordyceps sinensis, astragalus, and mushrooms. Recently, many evidences illustrate that natural plant polysaccharides possess various biological activities including strengthening immunity, lowering blood sugar, regulating lipid metabolism, antioxidation, antiaging, and antitumour. Plant polysaccharides have been widely used in the medical field due to their special features and low toxicity. As an important drug delivery system, liposomes can not only encapsulate small-molecule compound but also big-molecule drug; therefore, they present great promise for the application of plant polysaccharides with unique physical and chemical properties and make remarkable successes. This paper summarized the current progress in plant polysaccharides liposomes, gave an overview on their experiment design method, preparation, and formulation, characterization and quality control, as well as in vivo and in vitro studies. Moreover, the potential application of plant polysaccharides liposomes was prospected as well.

  9. Characterization and antitumor activity of a polysaccharide from Sarcodia ceylonensis.

    Science.gov (United States)

    Fan, Yijun; Lin, Mengchuan; Luo, Aoshuang; Chun, Ze; Luo, Aoxue

    2014-07-25

    A water-soluble polysaccharide from Sarcodia ceylonensis was obtained by using the method of water-extraction and ethanol-precipitation. The polysaccharide was further purified by chromatography on AB-8 and ADS-7 columns, yielding a pure polysaccharide termed SCP-60. The molecular weight (Mw) of SCP-60 was calculated to be 50.0 kDa, based on the calibration curve obtained with a series of Dextran T standards. The results of FT-IR indicated that the polysaccharide contains the α-configuration of sugar units. GC-MS analysis revealed that SCP-60 was mainly composed of galactose and glucose. NMR spectroscopy revealed SCP-60 had the backbone consisting of → 6)-α-Manp-(1 →, α-D-Glcp-(1 →, → 6)-α-D-Glcp-(1 → and → 6)-α-Galp-(1 →. In order to evaluate the antitumor activity in vivo of the polysaccharide, a sarcoma 180 model was used. The results showed SCP-60 had strong antitumor ability, meanwhile, SCP-60 at a high dose (100 mg/kg) could significantly increase the thymic and splenic indices of S180 mice, and strongly promote the secretion of IL-2, TNF-α and IFN-γ, increase the SOD activities and reduce the concentrations of MDA in blood. Therefore the polysaccharide SCP-60 should be explored as a novel potential antitumor drug.

  10. Phosphorylation of psyllium seed polysaccharide and its characterization.

    Science.gov (United States)

    Rao, Monica R P; Warrier, Deepa U; Gaikwad, Snehal R; Shevate, Prachi M

    2016-04-01

    Psyllium is widely used as a medicinally active natural polysaccharide for treating conditions like constipation, diarrhea, and irritable bowel syndrome, inflammatory bowel disease, ulcerative colitis and colon cancer. Studies have been performed to characterize and modify the polysaccharide obtained from psyllium seed husk and to evaluate its use as a pharmaceutical excipient, but no studies have been performed to evaluate the properties of the polysaccharide present in psyllium seeds. The present study focuses on phosphorylation of psyllium seed polysaccharide (PPS) using sodium tri-meta phosphate as the cross-linking agent. The modified phosphorylated psyllium seed polysaccharide was then evaluated for physicochemical properties, rheological properties, spectral analysis, thermal analysis, crosslinking density and acute oral toxicity studies. The modified polysaccharide (PhPPS) has a high swelling index due to which it can be categorized as a hydrogel. The percent increase in swelling of PhPPS as compared to PPS was found to be 90.26%. The PPS & PhPPS mucilages of all strengths were found to have shear thinning properties. These findings are suggestive of the potential use of PhPPS as gelling & suspending agent. PhPPS was found to have a mucoadhesive property which was comparable with carbopol.

  11. Regioselective sulfation of Artemisia sphaerocephala polysaccharide: Characterization of chemical structure.

    Science.gov (United States)

    Wang, Junlong; Yang, Wen; Wang, Jiancheng; Wang, Xia; Wu, Fang; Yao, Jian; Zhang, Ji; Lei, Ziqiang

    2015-11-20

    The biological activities of sulfated polysaccharides are related to the substitution positions of functional groups. In this study, regioselective sulfation of Artemisia sphaerocephala polysaccharides (SRSASP) was prepared by using triphenylchloromethane (TrCl) as protecting precursor. FT-IR spectra and X-ray photoelectron spectroscopy (XPS) showed that SO(3-) group (S(6+), high binding energy of 168.7eV) was widely present in sulfated polysaccharides. (13)C NMR spectroscopy showed that C-2 and C-3 substitution was occurred but not fully sulfation. Meanwhile, C-6 substituted signals near 65ppm were not observed. The degree of substitution varied from 0.44 to 0.63 in SRSASP which could be attributed to the low reactivity at secondary hydroxyl. Monosaccharide composition result showed a decrease in the ratio of mannose/glucose, indicating the change of chemical composition in sulfated polysaccharides. In size-exclusion chromatograph analysis, a decrease in molecular weight and broadening of molecular weight distribution of sulfated polysaccharides was also observed. It could be attributed to the hydrolysis of polysaccharide in the sulfated reaction.

  12. Health benefits of algal polysaccharides in human nutrition.

    Science.gov (United States)

    Mišurcová, Ladislava; Škrovánková, Soňa; Samek, Dušan; Ambrožová, Jarmila; Machů, Ludmila

    2012-01-01

    The interest in functional food, both freshwater and marine algal products with their possible promotional health effects, increases also in regions where algae are considered as rather exotic food. Increased attention about algae as an abundant source of many nutrients and dietary fiber from the nutrition point of view, as well as from the scientific approaches to explore new nutraceuticals and pharmaceuticals, is based on the presence of many bioactive compounds including polysaccharides extracted from algal matter. Diverse chemical composition of dietary fiber polysaccharides is responsible for their different physicochemical properties, such as their ability to be fermented by the human colonic microbiota resulted in health benefit effects. Fundamental seaweed polysaccharides are presented by alginates, agars, carrageenans, ulvanes, and fucoidans, which are widely used in the food and pharmaceutical industry and also in other branches of industry. Moreover, freshwater algae and seaweed polysaccharides have emerged as an important source of bioactive natural compounds which are responsible for their possible physiological effects. Especially, sulfate polysaccharides exhibit immunomodulatory, antitumor, antithrombotic, anticoagulant, anti-mutagenic, anti-inflammatory, antimicrobial, and antiviral activities including anti-HIV infection, herpes, and hepatitis viruses. Generally, biological activity of sulfate polysaccharides is related to their different composition and mainly to the extent of the sulfation of their molecules. Significant attention has been recently focused on the use of both freshwater algae and seaweed for developing functional food by reason of a great variety of nutrients that are essential for human health.

  13. Effect of sulfated modification on the molecular characteristics and biological activities of polysaccharides from Hypsizigus marmoreus.

    Science.gov (United States)

    Bao, HongHui; Choi, Won-Seok; You, SangGuan

    2010-01-01

    The effect of sulfated modification on polysaccharides from Hypsizigus marmoreus was examined by determining their molecular structures and bioactivities. The sulfation, which was implemented by using an orthogonal array design, produced polysaccharides with varying degrees of substitution (DS) ranging from 0.11 to 1.06. The sulfated polysaccharides exhibited a lower average molecular weight (M(w)) and considerably higher radius of gyration (R(g)) than those of native polysaccharide, suggesting that the conformation of the sulfated polysaccharides had been changed towards a more extended type. The inhibitory activity toward cancer cell growth was enhanced by treating with the sulfated polysaccharides by up to 34%, as compared to the native polysaccharide. In addition, treating with the sulfated polysaccharides increased the nitric oxide (NO) and cytokine (IL-1beta and TNF-alpha) release to levels comparable to those detected in the positive control, lipopolysaccharide (LPS), suggesting that the sulfated polysaccharides might have strong immunomodulatory activity.

  14. Structures of two cell wall-associated polysaccharides of a Streptococcus mitis biovar 1 strain. A unique teichoic acid-like polysaccharide and the group O antigen which is a C-polysaccharide in common with pneumococci

    DEFF Research Database (Denmark)

    Bergström, N; Jansson, P.-E.; Kilian, Mogens

    2000-01-01

    The cell wall of Streptococcus mitis biovar 1 strain SK137 contains the C-polysaccharide known as the common antigen of a closely related species Streptococcus pneumoniae, and a teichoic acid-like polysaccharide with a unique structure. The two polysaccharides are different entities and could...... to that of one of the two structures of C-polysaccharide previously identified in S. pneumoniae. C-polysaccharide of S. mitis is characterized by the presence, in each repeating unit, of two residues of phosphocholine and both galactosamine residues in the N-acetylated form. Immunochemical analysis showed that C......-polysaccharide constitutes the Lancefield group O antigen. Studies using mAbs directed against the backbone and against the phosphocholine moiety of the C-polysaccharide revealed several different patterns of these epitopes among 95 S. mitis and Streptococcus oralis strains tested and the exclusive presence of the group O...

  15. Structural studies of the O-specific polysaccharide(s) from the lipopolysaccharide of Azospirillum brasilense type strain Sp7.

    Science.gov (United States)

    Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

    2013-10-18

    Lipopolysaccharide was obtained by phenol-water extraction from dried bacterial cells of Azospirillum brasilense type strain Sp7. Mild acid hydrolysis of the lipopolysaccharide followed by GPC on Sephadex G-50 resulted in a polysaccharide mixture, which was studied by composition and methylation analyses, Smith degradation and (1)H and (13)C NMR spectroscopy. The following polysaccharide structures were established, where italics indicate a non-stoichiometric (∼40%) 2-O-methylation of l-rhamnose.

  16. The polysaccharide from Tamarindus indica (TS-polysaccharide) protects cultured corneal-derived cells (SIRC cells) from ultraviolet rays.

    Science.gov (United States)

    Raimondi, L; Lodovici, M; Guglielmi, F; Banchelli, G; Ciuffi, M; Boldrini, E; Pirisino, R

    2003-03-01

    The aim of this work was to investigate the possible protective effect of a new viscosising agent, TS-polysaccharide, on corneal-derived cells (SIRC) exposed to ultraviolet-B rays. To verify this, SIRC cells were first exposed, in the absence or in the presence of TS-polysaccharide (1% w/v), for 9 s at the UV-B source and then post-incubated for 45 min at 37 degrees C. After this period the hydrogen peroxide (H(2)O(2)) accumulated in the medium and the concentration of 8-hydroxy-2'-deoxy-guanosine (8-OHdG) in cell DNA was measured. In addition, the amount of (3)H-methyl-thymidine incorporated in cellular DNA was evaluated after 18 h from irradiation. Our results show that cells exposed to UV-B rays accumulate H(2)O(2), and have higher levels of 8OHdG and a lower amount of (3)H-methyl-thymidine incorporated in DNA than control cells. In the presence of TS-polysaccharide, the H(2)O(2) and 8-OHdG accumulation, and the (3)H-methyl-thymidine incorporation were significantly reduced with respect to the values measured in cells exposed in the absence of the polysaccharide. We propose a protective role of the polysaccharide in reducing UV-B derived DNA damage to eye cells. This finding could be of some clinical importance when the polysaccharide is used as a delivery system for ophthalmic preparations.

  17. Anticancer properties of polysaccharides isolated from fungi of the Basidiomycetes class.

    Science.gov (United States)

    Lemieszek, Marta; Rzeski, Wojciech

    2012-01-01

    Basidiomycete mushrooms represent a valuable source of biologically active compounds with anticancer properties. This feature is primarily attributed to polysaccharides and their derivatives. The anticancer potential of polysaccharides is linked to their origin, composition and chemical structure, solubility and method of isolation. Moreover, their activity can be significantly increased by chemical modifications. Anticancer effects of polysaccharides can be expressed indirectly (immunostimulation) or directly (cell proliferation inhibition and/or apoptosis induction). Among the wide range of polysaccharides with documented anticancer properties, lentinan, polysaccharide-K (PSK) and schizophyllan deserve special attention. These polysaccharides for many years have been successfully applied in cancer treatment and their mechanism of action is the best known.

  18. Antithrombin activity of an algal polysaccharide.

    Science.gov (United States)

    Trento, F; Cattaneo, F; Pescador, R; Porta, R; Ferro, L

    2001-06-01

    In an effort to reduce the risks of a possible iatrogenic transmission of bovine spongiform encephalitis (BSE) through the use of bovine-derived medicinal products, we patented in the USA in 1999 a polysaccharide from brown algae, endowed with interesting pharmacological activities: (a) concentration-dependent inhibition of thromboplastin or cephalin-kaolin-induced thrombin generation from platelets, (b) concentration-dependent inhibition of thrombin-induced platelet aggregation, (c) thrombin has hypotensive effect, which was blunted and zeroed by our fucansulfate in a dose-dependent way, (d) when aortae are stimulated with thrombin, they become stickier for polymorphonucleated leukocytes (PMNs); our fucansulfate decreased concentration-dependently, PMNs sticking to autologous rabbit aortae, (e) dose-dependent inhibition of thrombin-induced thrombosis. All the above data suggest that our fucansulfate could be a heparin substitute endowed with antithrombotic and anti-inflammatory activities, devoid or the problems caused to heparin by its animal origin, i.e., possible prion protein contamination.

  19. Immunomodulatory Polysaccharide from Chlorophytum borivilianum Roots

    Directory of Open Access Journals (Sweden)

    Mayank Thakur

    2011-01-01

    Full Text Available Chlorophytum borivilianum Santapau & Fernandes (Liliaceae is an ayurvedic Rasayana herb with immunostimulating properties. The polysaccharide fraction (CBP derived from hot water extraction of C. borivilianum (CB, comprising of ~31% inulin-type fructans and ~25% acetylated mannans (of hot water-soluble extract, was evaluated for its effect on natural killer (NK cell activity (in vitro. Human peripheral blood mononuclear cells (PBMCs, isolated from whole blood on a Ficoll-Hypaque density gradient, were tested in the presence or absence of varying concentrations of each C. borivilianum fraction for modulation of NK cell cytotoxic activity toward K562 cells. Preliminary cytotoxicity evaluation against P388 cells was performed to establish non-cytotoxic concentrations of the different fractions. Testing showed the observed significant stimulation of NK cell activity to be due to the CBP of C. borivilianum. Furthermore, in vivo evaluation carried out on Wistar strain albino rats for humoral response to sheep red blood cells (SRBCs and immunoglobulin-level determination using enzyme-linked immunosorbent assay (ELISA, exhibited an effectiveness of C. borivilianum aqueous extract in improving immune function. Present results provide useful information for understanding the role of CBP in modulating immune function.

  20. Animal lectins: potential receptors for ginseng polysaccharides

    Directory of Open Access Journals (Sweden)

    So Hee Loh

    2017-01-01

    Full Text Available Panax ginseng Meyer, belonging to the genus Panax of the family Araliaceae, is known for its human immune system-related effects, such as immune-boosting effects. Ginseng polysaccharides (GPs are the responsible ingredient of ginseng in immunomodulation, and are classified as acidic and neutral GPs. Although GPs participate in various immune reactions including the stimulation of immune cells and production of cytokines, the precise function of GPs together with its potential receptor(s and their signal transduction pathways have remained largely unknown. Animal lectins are carbohydrate-binding proteins that are highly specific for sugar moieties. Among many different biological functions in vivo, animal lectins especially play important roles in the immune system by recognizing carbohydrates that are found exclusively on pathogens or that are inaccessible on host cells. This review summarizes the immunological activities of GPs and the diverse roles of animal lectins in the immune system, suggesting the possibility of animal lectins as the potential receptor candidates of GPs and giving insights into the development of GPs as therapeutic biomaterials for many immunological diseases.

  1. Antioxidant properties of cell wall polysaccharides of Stevia rebaudiana leaves

    Directory of Open Access Journals (Sweden)

    Mediesse Kengne Francine

    2014-12-01

    Full Text Available Objective: To examine the total phenolic and protein contents, and the antioxidant activities of cell wall polysaccharide fractions of Stevia rebaudiana leaves. Methods: Three different polysaccharide-enriched fractions, namely FPE (extract with 50 mmol/ L ethylene diamine tetra acetic acid, FPK (extract with 0.05 mol/L KOH and FH (extract with 4 mol/L KOH were extracted from Stevia rebaudiana leaves. The antioxidant activity of these fractions was evaluated based on their ability to scavenge DPPH (1, 1-diphenyl-2-picryl hydrazyl free radical, to reduce ferric power, to chelate ferrous ion and to protect human DNA. Results: The results indicated that protein content was found to be higher in FPK polysaccharide enriched fraction (47.48 µg per mg of FPK. Furthermore, the phenolic compound analysis according to the Folin-Ciocalteu method was higher in FPK (17.71 µg ferulic acid. The DPPH maximal inhibition percentage of the three polysaccharide-enriched fractions at 400 µg/mL was 27.66%, 59.90% and 23.21% respectively for FPE, FPK and FH. All the polysaccharide fractions exhibited a ferric reducing power except the FH one. The three fractions also exhibited lipid peroxidation inhibition, and they completely reverted the DNA damage induced by H2O2/FeCl2. FPK showed the strongest scavenging activity against the DPPH radical, the best chelating ability and lipid peroxidation inhibition. Conclusions: Stevia cell wall polysaccharide fractions are potent protective agents against oxidative stress. The analysis revealed major differences in the antioxidant activity in the three polysaccharides fractions. However, the 0.05 mol/L KOH pectin fraction (FPK showed better antioxidant activity.

  2. Antioxidant properties of cell wall polysaccharides of Stevia rebaudiana leaves

    Institute of Scientific and Technical Information of China (English)

    Mediesse Kengne Francine; Woguia Alice Louise; Fogue Souopgui Pythagore; Atogho-Tiedeu Barbara; Simo Gustave; Thadde Boudjeko

    2014-01-01

    Objective: To examine the total phenolic and protein contents, and the antioxidant activities of cell wall polysaccharide fractions of Stevia rebaudiana leaves.Methods:L ethylene diamine tetra acetic acid), FPK (extract with 0.05 mol/L KOH) and FH (extract with 4 mol/L KOH) were extracted from Stevia rebaudiana leaves. The antioxidant activity of these fractions was evaluated based on their ability to scavenge DPPH (1, 1-diphenyl-2-picryl hydrazyl) free radical, to reduce ferric power, to chelate ferrous ion and to protect human DNA. Three different polysaccharide-enriched fractions, namely FPE (extract with 50 mmol/Results: The results indicated that protein content was found to be higher in FPK polysaccharide enriched fraction (47.48 µg per mg of FPK). Furthermore, the phenolic compound analysis according to the Folin-Ciocalteu method was higher in FPK (17.71 µg ferulic acid). The DPPH maximal inhibition percentage of the three polysaccharide-enriched fractions at 400 µg/mL was 27.66%, 59.90% and 23.21% respectively for FPE, FPK and FH. All the polysaccharide fractions exhibited a ferric reducing power except the FH one. The three fractions also exhibited lipid peroxidation inhibition, and they completely reverted the DNA damage induced by H2O2/FeCl2. FPK showed the strongest scavenging activity against the DPPH radical, the best chelating ability and lipid peroxidation inhibition.Conclusions: Stevia cell wall polysaccharide fractions are potent protective agents against oxidative stress. The analysis revealed major differences in the antioxidant activity in the three polysaccharides fractions. However, the 0.05 mol/L KOH pectin fraction (FPK) showed better antioxidant activity.

  3. Las películas folclóricas como manifestaciones más características del cine musical en España

    Directory of Open Access Journals (Sweden)

    Inmaculada Sánchez

    2010-10-01

    Full Text Available El cine musical producido en España incluye manifestaciones de vanguardia, como las películas de Carlos Saura. Sin embargo, los ejemplos más importantes de este género son los que tienen una finalidad comercial. El cine folclórico de temática andaluza es la manifestación más específica del musical español. En este artículo se establece primero un panorama general de la evolución experimentada por el género cinematográfico musical en España. Luego se analizan los rasgos narrativos más sobresalientes del cine folclórico durante su época de esplendor, entre mediados de los años treinta y principios de los sesenta. Por último, se trata de Pena, penita, pena (Miguel Morayta, 1953, protagonizada por una de las grandes estrellas del musical folclórico, Lola Flores, porque se trata de una coproducción concebida también para el mercado latinoamericano.

  4. Graphene-containing carbon aerogel prepared using polyethyleneimine (PEl)-modified graphene oxide (GO) for supercapacitor: effect of polyethyleneimine-modified GO content.

    Science.gov (United States)

    Lee, Yoon Jae; Lee, Joongwon; Kim, Gil-Pyo; Lee, Eo Jin; Yi, Jongheop; Song, In Kyu

    2014-11-01

    Graphene-containing carbon aerogel was prepared by a sol-gel polymerization of resorcinol-formaldehyde (RF) method using polyethyleneimine (PEL)-modified chemically exfoliated graphene oxide (GO), and its electrochemical performance as an electrode for supercapacitor was examined. The effect of PEI-modified GO content on the physicochemical and electrochemical properties of graphene-containing carbon aerogel was investigated. For comparison, graphene-free carbon aerogel was also prepared. Among the samples, graphene-containing carbon aerogel prepared using 45 wt% PEI-modified GO solution (CA(45PG)) showed the highest BET surface area (784 m2/g) and the largest pore volume (1.71 cm3/g) with well-developed porous structure. Electrochemical properties of graphene-containing carbon aerogel and graphene-free carbon aerogel electrodes were measured by cyclic voltammetry, charge/discharge test, and electrochemical impedance spectroscopy in 6 M KOH electrolyte. Various electrochemical measurements revealed that CA(45PG) showed the highest specific capacitance (261 F/g), the lowest equivalent series resistance (0.16 Ω), and superior capacitive behavior. It is concluded that PEI-modified GO content served as an important factor determining the physicochemical properties and supercapacitive electrochemical performance of graphene-containing carbon aerogel.

  5. Representación de género. Las películas españolas contemporáneas de adolescentes (2009-2014 

    Directory of Open Access Journals (Sweden)

    C Álvarez-Hernández

    2015-12-01

    Full Text Available Introducción. El presente estudio partió de los múltiples informes sobre los elevados índices de Desigualdad de Género en nuestra sociedad y de la gran influencia del relato audiovisual para la configuración de la misma. Nos planteamos si los largometrajes contemporáneos de producción española y de adolescentes reproducían esa imagen de género desigual. Metodología. Se estudió a los protagonistas de las películas más vistas con un elenco de adolescentes de más del 50% entre los años 2009-2014, analizando el número de personajes masculinos y femeninos en ellos y la reproducción de ocho estereotipos de género. Resultados. Los resultados manifestaron la reproducción de una imagen de género desigual, con estereotipos argumentales y de definición de personajes y roles que no hacen sino alimentar la creación y continuación de una imagen colectiva en los espectadores adolescentes sobre cómo son los hombres y las mujeres, contribuyendo a perpetuar la desigualdad de género.

  6. El cine y la generación de conocimiento en la educación empresarial: estudio de caso con la película Los Coristas

    Directory of Open Access Journals (Sweden)

    Alfredo Gorrochotegui

    2009-05-01

    Full Text Available Se describe la experiencia del uso de una película (“Los Coristas” como recurso didáctico para enseñar conductasde liderazgo a un grupo de trabajadores de una empresa de producción de alimentos, con el fin de prepararlospara la posterior compresión de un modelo específico de competencias de liderazgo. Antes de la observación de lapelícula se les entregó la ficha técnica de la misma, así como un cuestionario que debían contestar después de ver ellargometraje. A partir de las respuestas de dos participantes, se analiza si efectivamente son observables conductas deliderazgo en los personajes, y si éstas logran producir valoraciones y conclusiones que luego sirviesen para estudiarlas competencias de liderazgo. La experiencia con este grupo en particular, permitió validar que la observación de unapelícula y el uso del cine-foro facilitan procesos de reflexión, producción de ideas y preparación para introducirse ennuevas teorías y en la creación de conocimiento en el área organizacional.

  7. Rapid dome growth at Montagne Pelée during the early stages of the 1902 1905 eruption: a reconstruction from Lacroix's data

    Science.gov (United States)

    Tanguy, Jean-Claude

    2004-10-01

    Information obtained from various parts of the two books on Montagne Pelée by Lacroix enables an estimate to be made of the size of l’Etang Sec summit crater, the volume of the 1902 1905 lava dome and its growth rate at various stages of development. During the week preceding the 8 May nuée ardente, dome growth was between 28 and 38 m3 s 1, leading to a volume of 17 23×106 m3 on the morning of the catastrophe. Considering that significant parts of the dome (~1/3?) were removed by the 8 and 20 May climactic eruptions, a high magmatic flux could have continued until at least 27 May, when the total remaining volume was estimated to 53×106 m3. After moderate activity in June July (of order 10 m3 s 1), vigorous dome growth resumed dramatically, leading to the third climactic eruption of 30 August (a true calculation for this period being not feasible because of poor quality of the data). From November 1902 to July 1903 most of the effusive activity was concentrated in the great spine (erupted volume ~15×106 m3, magma flux 1.2 m3 s 1), which was eventually destroyed by collapse and minor nuées ardentes. The end of the eruption was characterized by a very low effusion rate, <1 m3 s 1 in average from August 1903 to October 1905.

  8. Cálculo de constantes ópticas de películas delgadas de Cu3BiS3 a través del método de Wolfe

    OpenAIRE

    2014-01-01

    Se calculó la obtención de las constantes ópticas usando el método de Wolfe. Dichas contantes: coeficiente de absorción (α), índice de refracción (n) y espesor de una película delgada (d ), son de importancia en el proceso de caracterización óptica del material. Se realizó una comparación del método del Wolfe con el método empleado por R. Swanepoel. Se desarrolló un modelo de programación no lineal con restricciones, de manera que fue posible estimar las constantes ópticas de películas delgad...

  9. Fabricación de películas delgadas de CU2 S mediante una reacción de sustitución iónica

    Directory of Open Access Journals (Sweden)

    Gerardo Gordillo Guzmán

    2010-12-01

    Full Text Available Se formaron películas delgadas de sulfuro cuproso (CU2S topotaxialmente sobre películas delgadas de sulfuro de cadmio (CdS mediante una reacción de intercambio de iones de Cu (I provenientes de una solución de CuCI con Iones de Cd (lI de la red de sulfuro de cadmio. Dos tipos diferentes de soluciones de CuCI fueron investigados y los resultados experimentales se evaluaron por medio de medidas de la característica corriente- voltaje (I-V de las celdas solares de CU2 S/CdS obtenidas. Eficiencias de conversión de 4.5% se lograron con dichas celdas solares.

  10. ¿Por qué es necesario realizar una educación mediática? Un análisis de caso con la película Cobardes

    Directory of Open Access Journals (Sweden)

    María Marcos Ramos

    2012-11-01

    Full Text Available El presente artículo pretende demostrar la necesidad de incorporar al currículo la educación mediática para que los alumnos puedan aplicarla cuando consuman contenidos mediáticos. Así, se ha utilizado para la investigación realizada una película dirigida al público adolescente, Cobardes (Juan Cruz y José Corbacho, 2008 y se ha analizado su mensaje en relación a la violencia. Mediante una encuesta realizada y analizando los resultados con la ayuda de la estadística, se ha podido demostrar que, a pesar de que es una película recomendada para mayores de 13 años, es necesario un visionado con mediación parental o escolar.

  11. El portafolis europeu de llengües en versió electrònica (ePEL+14: percepció preliminar del professorat universitari de la Xarxa Vives The electronic European Language Portfolio (eELP+14: first impressions of university teaching staff in the Vives Network El Portfolio Europeo de las Lenguas en versión electrónica (ePEL+14: percepción preliminar del profesorado universitario de la Red Vives

    Directory of Open Access Journals (Sweden)

    Olatz López Fernández

    2013-04-01

    Full Text Available Aquest article presenta el portafolis europeu de llengües en versió electrònica (ePEL+14 recentment validat pel Consell d'Europa. El propòsit és descriure aquesta innovació educativa en la docència universitària dels Erasmus Intensive Language Courses (EILC i conèixer l'opinió dels professors universitaris de llengua catalana de la Xarxa Vives participants en la primera preexperimentació amb aquesta innovació en el curs 2011-2012. Es va dur a terme una enquesta després d’un taller de l'ePEL+14 en els EILC. El qüestionari ad hoc contenia quatre dimensions: variables sociodemogràfiques, coneixement previ del PEL i ePEL, materials de suport per implementar-ho i conseqüències del seu ús en l'aprenentatge de la llengua. La valoració va ser positiva, especialment per l'adequació de l'eina tecnològica i les funcionalitats informatives i pedagògiques per a l’aprenent de llengües. No obstant això, també assenyalen una influència moderada en l’aprenentatge de la llengua i cultura. ____________________________________________________ Nous présentons ici le Portfolio européen des Langues en version électronique (ePEL+14 récemment validé par le Conseil de l'Europe. Le but est de décrire cette innovation éducative dans l'enseignement universitaire des Erasmus Intensive Language Courses (EILC et de faire connaître l'opinion des enseignants du supérieur de langue catalane du réseau Vives participant à la première pré-expérimentation avec cette innovation au cours de l'année universitaire 2011-2012. Nous avons réalisé une enquête après un atelier de l'ePEL+14 dans les EILC. Le questionnaire ad hoc comportait quatre dimensions: variables socio-démographiques; connaissance préalable du PEL et de l'ePEL; matériels de support pour la mise en œuvre; et conséquences de son utilisation dans l'apprentissage de la langue. L'évaluation a été positive, tout spécialement quant à l'adéquation de l

  12. An update on Pseudomonas aeruginosa biofilm formation, tolerance, and dispersal

    DEFF Research Database (Denmark)

    Harmsen, Morten; Yang, Liang; Pamp, Sünje Johanna

    2010-01-01

    . aeruginosa biofilms. The second messenger, c-di-GMP, is established as an important regulator of the synthesis of polysaccharide and protein components of the biofilm matrix. Extracellular DNA is shown to be an essential component of the biofilm matrix. It has become apparent that biofilm formation involves......We review the recent advances in the understanding of the Pseudomonas aeruginosa biofilm lifestyle from studies using in vitro laboratory setups such as flow chambers and microtiter trays. Recent work sheds light on the role of nutrients, motility, and quorum sensing in structure formation in P...... interactions between different subpopulations. The molecular mechanisms underlying the tolerance of biofilm bacteria to antimicrobial agents are beginning to be unraveled, and new knowledge has been obtained regarding the environmental cues and regulatory mechanisms involved in biofilm dispersal....

  13. Efeito da aplicação de película de fécula de mandioca na conservação pós-colheita de tomate

    Directory of Open Access Journals (Sweden)

    Damasceno Simone

    2003-01-01

    Full Text Available O presente trabalho teve por objetivo avaliar a qualidade e a vida útil pós-colheita de frutos de Tomate (Lycopersicon esculentum Mill utilizando recobrimento com película de fécula de mandioca. Após a seleção os frutos foram mergulhados em suspensões a 2 e 3% de fécula de mandioca, secos ao ar e armazenados em condição ambiente, onde a temperatura e a umidade relativa do período variaram de 16 a 21ºC e 51 a 91%, respectivamente. O experimento foi constituído de dois lotes de frutos, sendo o primeiro o grupo não-destrutivo (avaliação de perda de massa. O segundo lote de frutos, constituiu o grupo destrutivo no qual analisou-se textura, pH e sólidos solúveis totais. Os frutos foram avaliados aos 0, 4, 8, 11, 14, 18 e 22 dias. O delineamento experimental foi inteiramente casualizado, com cinco repetições para o primeiro grupo e três repetições para o grupo destrutivo. Os dados experimentais obtidos foram submetidos à analise de variância e as médias comparadas através do teste de Tukey ao nível de 5% de probabilidade. Os tratamentos não influenciaram significativamente a perda de massa e a textura. Entretanto, os frutos recobertos com película a 3% apresentaram melhor aparência do que os frutos testemunha e com película a 2%. O efeito das películas portanto, não foi prejudicial, apenas estético.

  14. Tratamiento Superficial de Acero Galvanizado con Películas Híbridas formadas por 3-(trimetoxisililpropil metacrilato (TMSPMA y Tetraetoxisilano (TEOS Surface Treatment of Galvanized Steel with Hybrid Films formed by 3-(trimethoxysilyl methacrylate (TMSPMA and Tetraethoxysilane (TEOS

    Directory of Open Access Journals (Sweden)

    Sandra R Kunst

    2012-01-01

    Full Text Available Acero galvanizado fue revestido con una película híbrida a partir de una solución formada por los precursores silanos 3-(trimetoxisililpropil metacrilato (TMSPMA y tetraetoxisilano (TEOS con adición de cerio. El uso de capas hibridas orgánico-inorgánico representa una alternativa ambientalmente aceptable para mejorar la resistencia de una serie de materiales metálicos frente a los procesos corrosivos. Se emplearon tres tiempos de inmersión (2, 10 y 15 minutos y se caracterizaron las películas mediante microscopia electrónica de barrido, evaluando también el carácter hidrofóbico de las películas. El comportamiento electroquímico de los revestimientos obtenidos fue determinado por el monitoreo del potencial de circuito abierto, polarización potenciodinámica e impedancia electroquímica. Los resultados que se obtuvo evidenciaron el efecto del tiempo de permanencia dentro de la solución en la uniformidad de la película y consecuentemente sobre la resistencia a la corrosión del mismo.Galvanized steel was coated with a hybrid film obtained from a solution formed by silane precursor 3-(trimethoxysilyl methacrylate (TMSPMA and tetraethoxysilane (TEOS with addition of cerium. The use of hybrid organic-inorganic layers represents an environmentally friendly alternative to improve resistance against corrosion of a series of metallic materials. Three immersion times (2, 10 and 15 minutes were used and the films were characterized by scanning electron microscope evaluating film wetability was at the same time. The electrochemical behavior of the coatings obtained was evaluated by open circuit potential, potentiodynamic polarization and electrochemical impedance. The results showed the effect of immersion time in the solution on the film uniformity and consequently on the corrosion resistance of these films.

  15. The Application of Polysaccharide Biocomposites to Repair Cartilage Defects

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2014-01-01

    Full Text Available Owing to own nature of articular cartilage, it almost has no self-healing ability once damaged. Despite lots of restore technologies having been raised in the past decades, no repair technology has smoothly substituted for damaged cartilage using regenerated cartilage tissue. The approach of tissue engineering opens a door to successfully repairing articular cartilage defects. For instance, grafting of isolated chondrocytes has huge clinical potential for restoration of cartilage tissue and cure of chondral injury. In this paper, SD rats are used as subjects in the experiments, and they are classified into three groups: natural repair (group A, hyaluronic acid repair (group B, and polysaccharide biocomposites repair (hyaluronic acid hydrogel containing chondrocytes, group C. Through the observation of effects of repairing articular cartilage defects, we concluded that cartilage repair effect of polysaccharide biocomposites was the best at every time point, and then the second best was hyaluronic acid repair; both of them were better than natural repair. Polysaccharide biocomposites have good biodegradability and high histocompatibility and promote chondrocytes survival, reproduction, and spliting. Moreover, polysaccharide biocomposites could not only provide the porous network structure but also carry chondrocytes. Consequently hyaluronic acid-based polysaccharide biocomposites are considered to be an ideal biological material for repairing articular cartilage.

  16. Soluble fiber polysaccharides: effects on plasma cholesterol and colonic fermentation.

    Science.gov (United States)

    Topping, D L

    1991-07-01

    Many soluble-fiber polysaccharides, used as stabilizers and thickeners by the food industry, lower plasma cholesterol and slow small intestinal transit and nutrient absorption. Although nondigestible by human enzymes, these polysaccharides are fermented by the large-bowel microflora, yielding short-chain fatty acids that are absorbed and contribute to energy. The caloric yield from fiber polysaccharides needs to be quantified. Short-chain fatty acid production from soluble fibers is modified by the presence of insoluble fibers but, in total, is probably less than from other carbohydrates, e.g., resistant starch. Short-chain fatty acids do not seem to mediate effects of fiber on plasma cholesterol, but in the large bowel they exert the trophic and antineoplastic effects of dietary fiber. The mechanism for cholesterol reduction by soluble fibers relates to enhanced steroid excretion and altered fat absorption and may be a function of the viscosity of these fibers in solution. The relationships between the chemical structure of soluble polysaccharides and their documented physiologic effects are not yet clear. By using polysaccharides of defined structure and properties, it should be possible to identify those characteristics that predict physiologic actions.

  17. Marine Polysaccharide Networks and Diatoms at the Nanometric Scale

    Directory of Open Access Journals (Sweden)

    Tea Mišić Radić

    2013-10-01

    Full Text Available Despite many advances in research on photosynthetic carbon fixation in marine diatoms, the biophysical and biochemical mechanisms of extracellular polysaccharide production remain significant challenges to be resolved at the molecular scale in order to proceed toward an understanding of their functions at the cellular level, as well as their interactions and fate in the ocean. This review covers studies of diatom extracellular polysaccharides using atomic force microscopy (AFM imaging and the quantification of physical forces. Following a brief summary of the basic principle of the AFM experiment and the first AFM studies of diatom extracellular polymeric substance (EPS, we focus on the detection of supramolecular structures in polysaccharide systems produced by marine diatoms. Extracellular polysaccharide fibrils, attached to the diatom cell wall or released into the surrounding seawater, form distinct supramolecular assemblies best described as gel networks. AFM makes characterization of the diatom polysaccharide networks at the micro and nanometric scales and a clear distinction between the self-assembly and self-organization of these complex systems in marine environments possible.

  18. Hypoglycemic effect of Ganoderma lucidum polysaccharides

    Institute of Scientific and Technical Information of China (English)

    Hui-na ZHANG; Zhi-bin LIN

    2004-01-01

    AIM: To investigate the hypoglycemic effect of Ganoderma lucidum polysaccharides (Gl-PS) in the normal fasted mice and its possible mechanism. METHODS: Normal fasted mice were given a single dose of Gl-PS 25, 50, and 100 mg/kg by ip and the serum glucose was measured at 0, 3, and 6 h after administration. Gl-PS 1 00 mg/kg were also given by ip and the serum glucose and insulin levels were measured at 0 min, 30 min, 1 h, 3 h, 6 h, and 12 h.Pancreatic islets were isolated and incubated with glucose 5.6 mmol/L and different concentration of Gl-PS, the insulin content of islets and insulin release were examined. The islets fluorescent intensity of [Ca2+]i was also studied with a confocal microscope. Verapamil and egtazic acid were used to testify whether the insulin-releasing effect of Gl-PS was mediated by its ability to raise the Ca2+ influx. RESULTS: Gl-PS dose-dependently lowered the serum glucose levels at 3 h and 6 h after administration. Gl-PS 100 mg/kg raised the circulating insulin levels at 1 h after administration. In vitro, Gl-PS had no effect on islets insulin content, but it stimulated the insulin release after incubation with glucose 5.6 mmol/L. Confocal microscope showed that Gl-PS 100 mg/L had the capacity to raise the [Ca2+] i. The insulin-releasing effect of Gl-PS was inhibited by verapamil/egtazic acid. CONCLUSION:Gl-PS possesses the hypoglycemic effect on normal mice; one mechanism is through its insulin-releasing activity due to a facilitation of Ca2+ inflow to the pancreatic β cells.

  19. Characterization of serological cross-reactivity between polysaccharide antigens of Streptococcus mutans serotypes c and d.

    OpenAIRE

    Grossi, S.; Prakobphol, A; Linzer, R; Campbell, L K; Knox, K W

    1983-01-01

    Immunological assays with antisera prepared against purified Streptococcus mutans serotype c polysaccharide demonstrated that a cross-reacting determinant on c polysaccharide reacted with the wall-associated rhamnose-glucose polysaccharide from S. mutans serotype d. Studies with 60 antisera prepared against chemostat cultures of S. mutans Ingbritt (c) demonstrated that the rhamnose-glucose polysaccharide cross-reactive determinant was consistently expressed on c antigen under a variety of gro...

  20. Application of gamma irradiation for the enhanced physiological properties of polysaccharides from seaweeds

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jong-il; Kim, Hyun-Joo; Kim, Jae-Hun; Byun, Myung-Woo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580185 (Korea, Republic of); Soo Chun, Byeong; Hyun Ahn, Dong [Department of Food Science and Biotechnology, Pukyong National University, Busan 608737 (Korea, Republic of); Hwang, Young-Jeong [Division of Food Science, Jinju International University, Jinju 660759 (Korea, Republic of); Kim, Duk-Jin [Division of Food Engineering and Nutrition, Daegu University, Daegu 712714 (Korea, Republic of); Kim, Gwang Hoon [Department of Biology, Kongju National University, Chungnam 314701 (Korea, Republic of); Lee, Ju-Woon [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580185 (Korea, Republic of)], E-mail: sjwlee@kaeri.re.kr

    2009-07-15

    Polysaccharides from seaweeds, fucoidan and laminarin, were irradiated with gamma rays, and their structural changes and anti-oxidative activities were investigated. The gamma irradiation decreased the average molecular weights of polysaccharides, and UV spectra of irradiated polysaccharides showed increases in the numbers of carboxyl and carbonyl groups and double bonds. DPPH radical scavenging ability and reducing power of the gamma irradiated polysaccharides were significantly higher than those non-irradiated.

  1. [Comparison on polysaccharide content and PMP-HPLC fingerprints of polysaccharide in stems and leaves of Dendrobium officinale].

    Science.gov (United States)

    Zhou, Gui-Fen; Pang, Min-Xia; Chen, Su-Hong; Lv, Gui-Yuan; Yan, Mei-Qiu

    2014-03-01

    In order to provide scientific basics for exploitation and sufficient application of Dendrobium officinale leaves resources, the phenol-sulfuric acid method was applied to determine the polysaccharide content. The monosaccharides were derivated by PMP and the derivatives were identified by HPLC-DAD-ESI-MS(n) and the contents of mannose and glucose were determined simultaneously. Similarity evaluation system for chromatographic fingerprint of traditional Chinese medicine (2004A) was employed to generate the mean chromatogram and similarity analysis of the samples was carried out. The results demonstrated that polysaccharide content, monosaccharide compositions and composition ratio had an obvious difference between stems and leaves. The polysaccharide content of stems was higher than that of leaves. Monosaccharide composition in leaf was significantly different from that in stem. The polysaccharide from stems was composed of mannose and glucose, however the polysaccharide of leaves was acid heteropolysaccharide and was mainly composed of five monosaccharides, including mannose, galacturonic acid, glucose, galactose and arabinose. The similarity value of the 14 batches was above 0.9, indicating that similarity of fingerprints among different samples was high. The study can provide evidence for expanding the medicinal parts of D. officinale.

  2. Polysaccharide-Based Membranes in Food Packaging Applications.

    Science.gov (United States)

    Ferreira, Ana R V; Alves, Vítor D; Coelhoso, Isabel M

    2016-01-01

    Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications.

  3. Production and characterization of the slime polysaccharide of Pseudomonas aeruginosa.

    Science.gov (United States)

    Evans, L R; Linker, A

    1973-11-01

    The slime polysaccharides produced by Pseudomonas aeruginosa isolated from a variety of human infections were investigated. Slime production in culture seemed optimal when adequate amounts of carbohydrate were present and under conditions of either high osmotic pressure or inadequate protein supply. The polysaccharides produced by the organisms were similar to each other, to the slime of Azotobacter vinelandii, and to seaweed alginic acids. They were composed of beta-1,4-linked d-mannuronic acid residues and variable amounts of its 5-epimer l-guluronic acid. All bacterial polymers contained o-acetyl groups which are absent in the alginates. The polysaccharides differed considerably in the ratio of mannuronic to guluronic acid content and in the number of o-acetyl groups. The particular composition of the slime was not found to be characteristic for the disease process from which the mucoid variants of P. aeruginosa were obtained.

  4. Preparation and characterization of mucilage polysaccharide for biomedical applications.

    Science.gov (United States)

    Archana, G; Sabina, K; Babuskin, S; Radhakrishnan, K; Fayidh, Mohammed A; Babu, P Azhagu Saravana; Sivarajan, M; Sukumar, M

    2013-10-15

    In the present investigation, the polysaccharide/mucilage from waste of Abelmoscus esculentus by modification in hot extraction using two different solvents (Acetone, Methanol) were extracted, characterized and further compared with seaweed polysaccharide for their potential applications. The percentage yield, emulsifying capacity and swelling index of this mucilage were determined. The macro algae and okra waste, gave high % yield (22.2% and 8.6% respectively) and good emulsifying capacity (EC%=52.38% and 54.76% respectively) with acetone, compared to methanol (11.3% and 0.28%; EC%=50%) (PH=7) while swelling index was greater with methanol than acetone extracts respectively. The infrared (I.R.) spectrum of the samples was recorded to investigate the chemical structure of mucilage. Thermal analysis of the mucilage was done with TGA (Thermal Gravimetric Analyzer) and DSC (Differential Scanning Calorimeter) which showed both okra and algal polysaccharide were thermostable hydrogels.

  5. Gelation of soybean protein and polysaccharides delays digestion.

    Science.gov (United States)

    Hu, Bing; Chen, Qing; Cai, Qimeng; Fan, Yun; Wilde, Peter J; Rong, Zhen; Zeng, Xiaoxiong

    2017-04-15

    Xanthan gum and carrageenan, representing the medium and highly negatively charged polysaccharides, were heated respectively together with soybean protein isolate (SPI) at different biopolymer ratios. Upon mixing with simulated stomach juice (SSJ), the xanthan-SPI and carrageenan-SPI at biopolymer ratios higher than 0.01 leads to self-assembled gelation immediately. Stronger gel is formed under higher biopolymer ratios. Highly negatively charged carrageenan forms a stronger gel than that composed with xanthan gum. SDS-PAGE results show the digestibility of SPI is delayed after incorporation with the polysaccharides, which is enhanced with the increase of the biopolymer mass ratios. And the polysaccharide with higher negative charge has stronger potential in delaying the digestion of SPI. Furthermore, the microstructure of the xanthan-SPI and carrageenan-SPI gel before and after simulated stomach digestion was characterized by scanning electron microscope (SEM), which also confirms that the gel delays the digestion of soybean protein.

  6. Microwave-assisted extraction of polysaccharides from solanum nigrum

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-qing; LIU-qin; JIANG xin-yu; ZENG fan

    2005-01-01

    The microwave-assisted method was used to extract polysaccharides from solanum nigrum. The optimum experimental parameters, mechanism of the extraction and the effect of microwave-assisted extraction process on the structures of polysaccharides were investigated. The extract was analyzed by the modified phenol-sulfuric acid method at 490 nm. The optimum experimental parameters were obtained by orthogonal experiments as follows: extraction time 15 min, microwave radiation power 455 W and the process ratio of materials mass to solvent volume 1∶20. The results show that compared with the conventional reflux extraction, the microwave-assisted extraction has a higher yield in shorter time, with no effect on the finally obtained polysaccharides as seen from the FT-IR spectra. The scanning electron microscopy images reveal that the mechanism of the extraction is related to the structural changes of the plant cells in different extracting conditions.

  7. Polysaccharide-Based Membranes in Food Packaging Applications

    Science.gov (United States)

    Ferreira, Ana R. V.; Alves, Vítor D.; Coelhoso, Isabel M.

    2016-01-01

    Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications. PMID:27089372

  8. Optimization of enzyme assisted extraction of polysaccharides from Ganoderma lucidum

    Institute of Scientific and Technical Information of China (English)

    Xu Chunhua; Tian Zhenle; Zhang Chenju; Yu Xiaobing; Zheng Huihua

    2014-01-01

    In the present work,an enzyme assisted extraction method is used to isolate crude polysaccharides from Ganoderma lucidum. The isolating effect was optimized with orthographic graph statistic method with three levels and four independent variables. Complex enzyme,extraction temperature,extraction time and ex-traction pH were combined to obtain the best possible combination to get maximum amount of extract and crude polysaccharides yield. The optimum extraction conditions were:complex enzyme amount of 3%(w/v),extrac-tion temperature at 45℃,extraction time of 3 h and extraction pH at 7. Under these conditions,the experimen-tal amount of extract is 8.9%and the yield of crude polysaccharides is 1.1%,which are in close agreement with the value predicted by the model.

  9. Polysaccharide-Based Membranes in Food Packaging Applications

    Directory of Open Access Journals (Sweden)

    Ana R. V. Ferreira

    2016-04-01

    Full Text Available Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications.

  10. Structural and biological study of carboxymethylated Phellinus linteus polysaccharides.

    Science.gov (United States)

    Shin, Ji-Yoon; Lee, Suyong; Bae, In Young; Yoo, Sang-Ho; Lee, Hyeon Gyu

    2007-05-02

    Polysaccharides isolated from Phellinus linteus were chemically modified by carboxymethylation, and the structural and physiological properties of the derivative were investigated. 13C NMR spectroscopy showed that the polysaccharides extracted from P. linteus contained (1-3)-beta-glucans with a (1-6)-linkage. The carboxymetehylation of the P. linteus polysaccharides was confirmed by Fourier transform infrared spectroscopy, and the degree of substitution was obtained by the potentiometric titration, which was calculated to be 0.63. The bronchoalveolar lavage experiments showed that the carboxymethylated derivative raised the nitric oxide production. In addition, the carboxymethylation stimulated in vitro cytotoxic activity against the HT1080 cell line. Thus, the derivative exhibited the enhanced activity of immune systems, which would be explained by the improved water solubility and structural changes by carboxymethylation. However, a slight decrease in the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity of the derivative was observed.

  11. Designing Whey Protein-Polysaccharide Particles for Colloidal Stability.

    Science.gov (United States)

    Wagoner, Ty; Vardhanabhuti, Bongkosh; Foegeding, E Allen

    2016-01-01

    Interactions between whey proteins and polysaccharides, in particular the formation of food-grade soluble complexes, are of interest because of potential functional and health benefits. A specific application that has not received much attention is the use of complexes for enhanced colloidal stability of protein sols, such as protein-containing beverages. In beverages, the primary goal is the formation of complexes that remain dispersed after thermal processing and extended storage. This review highlights recent progress in the area of forming whey protein-polysaccharide soluble complexes that would be appropriate for beverage applications. Research in this area indicates that soluble complexes can be formed and stabilized that are reasonably small in size and possess a large surface charge that would predict colloidal stability. Selection of specific proteins and polysaccharides can be tailored to desired conditions. The principal challenges involve overcoming restrictions on protein concentration and ensuring that protein remains bioavailable.

  12. Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

    Directory of Open Access Journals (Sweden)

    Rui Manuel Santos Costa de Morais

    2013-01-01

    Full Text Available Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina, and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS. It goes through the most studied activities of sulphated polysaccharides (sPS or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.

  13. Progress in the research and application of polysaccharide hemostatic materials

    Directory of Open Access Journals (Sweden)

    Yi JIANG

    2015-01-01

    Full Text Available Local hemostasis is the first step in wound treatment, and effective hemostatic methods could reduce the number of unnecessary casualties. Hemostatic materials need to have good hemostatic properties, excellent biocompatibility, no toxic side effects, no irritation and easy to prepare. The polysaccharide has many advantages, including rich source, simple structures, absorbable and biodegradable, excellent biocompatibility. At present, it has been found that polysaccharide is easy to modify in structure and recombine. This paper summarizes the characteristics and products of polysaccharide hemostatic materials including celluloses, chitosans, alginate, hyaluronic acid, and starch in order to offer the indications for clinical application and further study. DOI: 10.11855/j.issn.0577-7402.2014.12.16

  14. Polysaccharides of higher fungi: Biological role, structure, and antioxidative activity

    Directory of Open Access Journals (Sweden)

    Kozarski Maja S.

    2014-01-01

    Full Text Available Fungal polysaccharides attract a lot of attention due to their multiple challenging biological properties, such as: anti-tumor, anti-viral, anticomplementary, anticoagulant, hypolipidemic and immunomodulatory and immune-stimulatory activities, which all together make them suitable for application in many quite distinctive areas, such as food industry, biomedicine, cosmetology, agriculture, environmental protection and waste water management. This article presents results with respect to biological properties, structure and procedures related to the isolation and activation of polysaccharides of higher fungi. It is considered and presented along with a review of the critical antioxidative activity and possible influence of the structural composition of polysaccharide extracts (isolated from these higher fungi upon their antioxidative properties.

  15. Bioactivity and applications of sulphated polysaccharides from marine microalgae.

    Science.gov (United States)

    Raposo, Maria Filomena de Jesus; de Morais, Rui Manuel Santos Costa; Bernardo de Morais, Alcina Maria Miranda

    2013-01-23

    Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina), and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS). It goes through the most studied activities of sulphated polysaccharides (sPS) or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.

  16. Pleurotus eryngii Polysaccharide Promotes Pluripotent Reprogramming via Facilitating Epigenetic Modification.

    Science.gov (United States)

    Deng, Wenwen; Cao, Xia; Wang, Yan; Yu, Qingtong; Zhang, Zhijian; Qu, Rui; Chen, Jingjing; Shao, Genbao; Gao, Xiangdong; Xu, Ximing; Yu, Jiangnan

    2016-02-17

    Pleurotus eryngii is a medicinal/edible mushroom with great nutritional value and bioactivity. Its polysaccharide has recently been developed into an effective gene vector via cationic modification. In the present study, cationized P. eryngii polysaccharide (CPS), hybridized with calcium phosphate (CP), was used to codeliver plasmids (Oct4, Sox2, Klf4, c-Myc) for generating induced pluripotent stem cells (iPSCs). The results revealed that the hybrid nanoparticles could significantly enhance the process and efficiency of reprogramming (1.6-fold increase) compared with the CP nanoparticles. The hybrid CPS also facilitated epigenetic modification during the reprogramming. Moreover, these hybrid nanoparticles exhibited multiple pathways (both caveolae- and clathrin-mediated endocytosis) in their cellular internalization, which accounted for the improved iPSCs generation. These findings therefore present a novel application of P. eryngii polysaccharide in pluripotent reprogramming via active epigenetic modification.

  17. Modulation of surgical fibrosis by microbial zwitterionic polysaccharides

    Science.gov (United States)

    Ruiz-Perez, Begonia; Chung, Doo R.; Sharpe, Arlene H.; Yagita, Hideo; Kalka-Moll, Wiltrud M.; Sayegh, Mohamed H.; Kasper, Dennis L.; Tzianabos, Arthur O.

    2005-11-01

    Bacterial carbohydrates have long been considered T cell-independent antigens that primarily induce humoral immune responses. Recently, it has been demonstrated that bacterial capsules that possess a zwitterionic charge motif can activate CD4+ T cells after processing and presentation by antigen-presenting cells. Here we show that these zwitterionic polysaccharides can prevent T helper 1-mediated fibrosis by signaling for the release of IL-10 from CD4+ T cells in vivo. IL-10 production by these T cells and their ability to prevent fibrosis is controlled by the inducible costimulator (ICOS)-ICOS ligand pathway. These data demonstrate that the interaction of the zwitterionic polysaccharides with T cells results in modulation of surgical fibrosis in vivo and suggest a previously undescribed approach to "harnessing" T cell function to prevent inflammatory tissue disorders in humans. IL-10 | microbial polysaccharides | inducible costimulator

  18. Antioxidant activity of herbal polysaccharides and cough reflex.

    Science.gov (United States)

    Nosalova, G; Jurecek, L; Hromadkova, Z; Kostalova, Z; Sadlonova, V

    2013-01-01

    The extraction of Fallopia sachalinensis leaves resulted in two fractions (FS-1 and FS-2). Chemical and spectral analyses of samples revealed the prevalence of pectic polysaccharides with high galacturonic acid, arabinose, galactose, and rhamnose content. Arabinogalactan with a higher content of phenolic prevailed in the FS-1, whereas rhamnogalacturonan predominated in the FS-2 fraction. Both polysaccharides showed significant antioxidant activity according to DPPH and FRAP assays. Evaluation of antitussive activity in healthy adult conscious guinea pigs after oral application of 50 and 75 mg/kg of the FS-2 polysaccharide extracts showed a significant suppression of cough reflex, without an influence on specific airway resistance. The suppression of cough was comparable with that of codeine.

  19. Marine Polysaccharides from Algae with Potential Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Maria Filomena de Jesus Raposo

    2015-05-01

    Full Text Available There is a current tendency towards bioactive natural products with applications in various industries, such as pharmaceutical, biomedical, cosmetics and food. This has put some emphasis in research on marine organisms, including macroalgae and microalgae, among others. Polysaccharides with marine origin constitute one type of these biochemical compounds that have already proved to have several important properties, such as anticoagulant and/or antithrombotic, immunomodulatory ability, antitumor and cancer preventive, antilipidaemic and hypoglycaemic, antibiotics and anti-inflammatory and antioxidant, making them promising bioactive products and biomaterials with a wide range of applications. Their properties are mainly due to their structure and physicochemical characteristics, which depend on the organism they are produced by. In the biomedical field, the polysaccharides from algae can be used in controlled drug delivery, wound management, and regenerative medicine. This review will focus on the biomedical applications of marine polysaccharides from algae.

  20. VISCOSITY BEHAVIOR OF LACQUER POLYSACCHARIDE IN AQUEOUS SOLUTION

    Institute of Scientific and Technical Information of China (English)

    QIU Xingping; ZHANG Lina; DU Yumin; QIAN Baogong

    1991-01-01

    The dependence of measured viscosity on NaCl concentration (0.1 to 3.0M), pH (range of 2-13) and cadoxen composition Wcad (from 2% to 100% ) for the lacquer polysaccharide in NaCl/cadoxen/H2O mixture containing HCl or without were obtained. All the viscosity exponents γ in the Mark-Houwink equations under three different solvent condition are close to 0.5. The wcad dependence of reduced viscosity ηsp/c confirms the single strand chain of the polysaccharide. As the γ values close to 0.5 and values of unperturbed dimension θ/M and [η] much smaller than those for usual linear polymers, these facts suggest that the polysaccharide chains in the aqueous solutions should be dense random coil owing to the highly branched structure.

  1. Isolation of Polysaccharides Sulfated during Early Embryogenesis in Fucus.

    Science.gov (United States)

    Hogsett, W E; Quatrano, R S

    1975-01-01

    Beginning 10 hours after fertilization, zygotes of Fucus distichus L. Powell incorporate (35)S into polysaccharides as a sulfate ester of fucose. These sulfated polysaccharides are sequestered in only the rhizoid cell of the two-celled embryo and can serve as a marker of cellular differentiation. Zygotes were pulsed at different times after fertilization with Na(2) (35)SO(4) to identify and isolate the fucans localized within the region of cytoplasm destined to become the rhizoid cell. Low molecular weight pools of (35)S were saturated within 60 minutes, with the greatest incorporation into ethanol-soluble and insoluble fractions occurring with 0.1 mm Na(2)SO(4) in the artificial sea water medium. At the time of rhizoid formation, four fucose-containing polysaccharide fractions incorporated (35)S. When each fraction was subjected to diethylaminoethyl chromatography, two components were eluted with KCl that contained over 84% of the fucose and 93% of the (35)S of the particular fraction. Highvoltage paper electrophoresis of each fraction also resulted in the separation of these two major components. Both components from each of the four fractions behaved identically when separated by diethylaminoethyl chromatography and paper electrophoresis. By comparing the incorporation of (35)S into the polysaccharide fractions at 4 and 16 hours after fertilization, the fucan-sulfate components that are localized in the cytoplasm at the time of rhizoid formation were isolated. Although sulfated polysaccharides in brown algae are reported to be very heterogeneous in terms of their sugar composition and complexes with other heteropolymers, we propose that there are two major components that are sulfated during early embryogenesis in Fucus. The location of these two sulfated polysaccharides in different chemical fractions may reflect their subcellular localization (e.g., cytoplasmic vesicles or cell walls), or their association with other heteropolymers.

  2. Characterization of the Kingella kingae polysaccharide capsule and exopolysaccharide.

    Directory of Open Access Journals (Sweden)

    Kimberly F Starr

    Full Text Available Recent evidence indicates that Kingella kingae produces a polysaccharide capsule. In an effort to determine the composition and structure of this polysaccharide capsule, in the current study we purified capsular material from the surface of K. kingae strain 269-492 variant KK01 using acidic conditions to release the capsule and a series of steps to remove DNA, RNA, and protein. Analysis of the resulting material by gas chromatography and mass spectrometry revealed N-acetyl galactosamine (GalNAc, 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo, and galactose (Gal. Further analysis by NMR demonstrated two distinct polysaccharides, one consisting of GalNAc and Kdo with the structure →3-β-GalpNAc-(1→5-β-Kdop-(2→ and the other containing galactose alone with the structure →5-β-Galf-(1→. Disruption of the ctrA gene required for surface localization of the K. kingae polysaccharide capsule resulted in elimination of GalNAc and Kdo but had no effect on the presence of Gal in bacterial surface extracts. In contrast, deletion of the pamABCDE locus involved in production of a reported galactan exopolysaccharide eliminated Gal but had no effect on the presence of GalNAc and Kdo in surface extracts. Disruption of ctrA and deletion of pamABCDE resulted in a loss of all carbohydrates in surface extracts. These results establish that K. kingae strain KK01 produces a polysaccharide capsule with the structure →3-β-GalpNAc-(1→5-β-Kdop-(2→ and a separate exopolysaccharide with the structure →5-β-Galf-(1→. The polysaccharide capsule and the exopolysaccharide require distinct genetic loci for surface localization.

  3. Analytical Model for Electronic Transport in Semiconductor Thin Films Modelo analítico para el transporte electrónico en películas delgadas semiconductoras

    Directory of Open Access Journals (Sweden)

    M Torres-Luengo

    2013-11-01

    ás, la teoría de tunelamiento cuántico de portadores a través de la barrera de potencial. Dado que la estructura de las películas delgadas de trióxido de Molibdeno (MoO3 obtenidas por atomización pirolítica es de tipo granular y de tamaño nanométrico, el modelo analítico explica el comportamiento de la característica Corriente - Voltaje (I-V de las películas. 

  4. Efecto de la temperatura sobre películas de un aislado proteico del suero bovino (WPI adsorbidas sobre la interfase aceite-agua

    Directory of Open Access Journals (Sweden)

    Rodríguez Patino, Juan M.

    2002-09-01

    ómetro dinámico de gota, en unión de la observación microscópica y posterior análisis de la imagen de una gota que tiene adsorbida a la proteína sobre su superficie. Las variables estudiadas fueron la temperatura (en el intervalo comprendido entre 20 y 80 ºC y la concentración de proteína en el seno de la fase acuosa (en el intervalo comprendido entre 1.10-1 y 1.10-5% en peso. Durante el tratamiento térmico, (a la película de WPI presenta un comportamiento viscoelástico, con un ángulo de fase distinto de cero, (b se incrementa el carácter elástico de la interfase, (c se produce un incremento del módulo dilatacional superficial (E y (d una disminución de la tensión interfacial. La variación de E con el tiempo puede cuantificarse mediante ecuaciones de primer orden que pueden relacionarse con dos mecanismos cinéticos, asociados con la gelificación de WPI sobre la interfase aceite-agua. El tratamiento térmico produce cambios irreversibles en la película de WPI adsorbida sobre la interfase. Se han observado cambios significativos en las características interfaciales y en la imagen de la gota a concentraciones de proteína tan bajas como 1.10-5% en peso.

  5. Processing of Polymer Nanocomposites Reinforced with Polysaccharide Nanocrystals

    Directory of Open Access Journals (Sweden)

    Alain Dufresne

    2010-06-01

    Full Text Available Aqueous suspensions of polysaccharide (cellulose, chitin or starch nanocrystals can be prepared by acid hydrolysis of biomass. The main problem with their practical use is related to the homogeneous dispersion of these nanoparticles within a polymeric matrix. Water is the preferred processing medium. A new and interesting way for the processing of polysaccharide nanocrystals-based nanocomposites is their transformation into a co-continuous material through long chain surface chemical modification. It involves the surface chemical modification of the nanoparticles based on the use of grafting agents bearing a reactive end group and a long compatibilizing tail.

  6. Analysis of Polysaccharides in Shii - Take fiom Guizhou

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Polysaccharides, special those with physiological actions and nutrition, are widely used as an important resources for food, medicine industries, health etc. Herba Glossogynes Tenuifoliae (Shii-Take) is rich in polysaccharides with physiological actions and nutrition. Guizhou lies to the southwest of China, Natural resources abound in this province, in which there is high output and many species of Shii-Fake. So study in the Shii-Take is favor of reasonably utilizing the natural resources and getting high addvalue products. And what is more, It is necessary for energetically developing west economy.

  7. Chitosan: A Promising Marine Polysaccharide for Biomedical Research.

    Science.gov (United States)

    Periayah, Mercy Halleluyah; Halim, Ahmad Sukari; Saad, Arman Zaharil Mat

    2016-01-01

    Biomaterials created 50 years ago are still receiving considerable attention for their potential to support development in the biomedical field. Diverse naturally obtained polysaccharides supply a broad range of resources applicable in the biomedical field. Lately, chitosan, a marine polysaccharide derived from chitins-which are extracted from the shells of arthropods such as crab, shrimp, and lobster-is becoming the most wanted biopolymer for use toward therapeutic interventions. This is a general short review of chitosan, highlighting the history, properties, chemical structure, processing method, and factors influencing the usage of chitosan derivatives in the biomedical field.

  8. Extraction of Opuntia dillenii Haw. Polysaccharides and Their Antioxidant Activities

    OpenAIRE

    Heng Li; Qingxia Yuan; Xianjiao Zhou; Fuhua Zeng; Xiangyang Lu

    2016-01-01

    Use of natural polysaccharides in medicine and food has wide interest in research. In this study, we extracted and purified some polysaccharides from cactus Opuntia dillenii Haw. (ODP). Some preliminary functions of these products were characterized. Under the optimal purification conditions, the yield of ODP extracted from the 2–4 month-old Opuntia dillenii Haw. (T-ODP) was 30.60% ± 0.40%, higher than that of ODP from the 5–10 month-old materials (O-ODP) (18.97% ± 0.58%). The extracted ODP w...

  9. Chitosan: A promising marine polysaccharide for biomedical research

    Directory of Open Access Journals (Sweden)

    Mercy Halleluyah Periayah

    2016-01-01

    Full Text Available Biomaterials created 50 years ago are still receiving considerable attention for their potential to support development in the biomedical field. Diverse naturally obtained polysaccharides supply a broad range of resources applicable in the biomedical field. Lately, chitosan, a marine polysaccharide derived from chitins—which are extracted from the shells of arthropods such as crab, shrimp, and lobster—is becoming the most wanted biopolymer for use toward therapeutic interventions. This is a general short review of chitosan, highlighting the history, properties, chemical structure, processing method, and factors influencing the usage of chitosan derivatives in the biomedical field.

  10. Structural characterization of Lytic Polysaccharide MonoOxygenases

    DEFF Research Database (Denmark)

    Frandsen, Kristian Erik Høpfner

    Lytic polysaccharide monooxygenases (LPMOs) are a new class of copper-containingmetalloenzymes that have been found to oxidatively degrade polysaccharides (and recently alsooligosaccharides). They dependent on redox partners to provide them with electrons and they utilizemolecular oxygen to cleave......) and their interaction with substratehave been structurally characterized. A number of structures of LsAA9A have been obtained in complexwith a range of cellulosic- and hemicellulosic substrates and with the active site Cu in different redox state.Two of the LsAA9A structures with the active site Cu in essentially a Cu...

  11. Analysis of Polysaccharides in Shii - Take fiom Guizhou

    Institute of Scientific and Technical Information of China (English)

    MO; Liping

    2001-01-01

    Polysaccharides, special those with physiological actions and nutrition, are widely used as an important resources for food, medicine industries, health etc. Herba Glossogynes Tenuifoliae (Shii-Take) is rich in polysaccharides with physiological actions and nutrition.  Guizhou lies to the southwest of China, Natural resources abound in this province, in which there is high output and many species of Shii-Fake. So study in the Shii-Take is favor of reasonably utilizing the natural resources and getting high addvalue products. And what is more, It is necessary for energetically developing west economy.……

  12. Comportamiento de películas delgadas de níquel y óxido de níquel en NaCl al 3 %

    Directory of Open Access Journals (Sweden)

    Magaña, C. R.

    2006-02-01

    Full Text Available The aim of this work is to study the behaviour of both: a nickel thin film deposited on steel AISI 1018 (UNS G 10180 and a superior nickel oxide electrochemically obtained on the film; with the purpose of decreasing the corrosion rate of low carbon steel immersed in a solution of NaCl 3% wt, thus efficient anticorrosive protection could be obtained. Two film deposition techniques were used: electrochemical and magnetron DC sputtering; and the protective properties of deposited films exposed to the aggressive media, were evaluated. The characterization of different films was carried out by using electrochemical techniques: polarization curves and electrochemical impedance.

    Este trabajo se enfoca al comportamiento que presenta una película delgada de níquel depositada sobre acero al carbón AISI 1018 (UNS G 10180 y un óxido superior del mismo níquel, con el propósito de disminuir la velocidad de corrosión del acero cuando se expone a una solución de NaCl al 3 % y obtener así una protección anticorrosiva alternativa eficaz. En este trabajo se comparan dos técnicas de depósito: electroquímico y decapado catódico o Magnetron DC Sputtering, y se evalúa la protección a la corrosión de cada depósito frente al medio agresivo. La caracterización de los diferentes depósitos se realizó a través de técnicas electroquímicas, (curvas de polarización y espectroscopia de impedancia.

  13. PLAYHIST: Jugando con la Historia. Transformación de película interactiva en juego histórico para el aprendizaje

    Directory of Open Access Journals (Sweden)

    Pablo Aguirrezabal

    2014-10-01

    Full Text Available Dentro de los espacios museísticos y centros de interpretación, una de cuyas funciones principales es la preservación y divulgación de los recursos históricos, es importante conectar con el público visitante con unas formas de comunicación modernas, accesibles, interesantes y con las que esté familiarizado. Con este objetivo, la introducción de nuevas tecnologías que faciliten las tareas de ilustrar, enseñar, interesar al visitante es clave. A través del experimento PLAYHIST, Tecnalia pretende la transformación de una película interactiva sobre la Antigua Grecia en un juego serio histórico multijugador, que sobre el mismo entorno del Tholos en el Hellenic Cosmos de Atenas (Grecia, tratará de demostrar que el aprendizaje por parte de los visitantes en museos y centros culturales puede incrementarse a través de la introducción del concepto de gamificación de los contenidos históricos. Dentro de este experimento se definirán una serie de métricas que afectan tanto al servicio, como a la experiencia de usuario y el aprendizaje. Estas métricas se recogerán tanto con los componentes software del juego como a través de cuestionarios a los propios visitantes. El análisis posterior de los datos recogidos dará una pista sobre si el concepto de “Learning by playing” es válido en este tipo de centros culturales.

  14. Degeneração marginal pelúcida da córnea: diagnóstico e tratamento Pellucid marginal degeneration: diagnosis and treatment

    Directory of Open Access Journals (Sweden)

    Rafael Vidal Mérula

    2006-06-01

    Full Text Available A degeneração marginal pelúcida da córnea caracteriza-se por afilamento estromal progressivo do segmento inferior da córnea, estendendo-se na posição de 4 horas às 8 horas, em forma de crescente. A área de adelgaçamento corneal mede entre 1 mm e 2 mm de largura e é separada do limbo corneoescleral por uma área de tecido corneal normal. Como no ceratocone, o tratamento inicial consiste na correção óptica com óculos ou lentes de contato rígidas. Entretanto, quando a doença apresenta-se em estágio avançado, inviabiliza-se a correção visual por meio de recursos ópticos, sendo necessária a utilização de procedimentos cirúrgicos, como a ressecção em cunha, ressecção lamelar em crescente, a ceratoplastia penetrante, a ceratoplastia lamelar, epiceratoplastia, e mais recentemente os implantes de anéis corneais intra-estromais.Pellucid marginal degeneration is characterized by a progressive stromal thinning of the inferior corneal segment, between 4 and 8 o'clock, with a crescentic shape. The area of corneal thinning has a width of about 1 to 2 mm, and it is separated from the corneoscleral limbus by an area of normal corneal tissue. The initial treatment consists of optical correction. However, when the disease progresses to advanced stages, surgical procedures are necessary such as wedge resection, lamellar crescentic resection, penetrating keratoplasty, lamellar keratoplasty, epikeratoplasty and, recently, intracorneal segments.

  15. Propriedades físicas de painéis aglomerados de madeira produzidos com adição de película de polipropileno biorientado

    Directory of Open Access Journals (Sweden)

    Laurenn B. de Macedo

    2015-07-01

    Full Text Available No Brasil, as últimas décadas foram marcadas pela crescente produção de paineis de madeira seguida pelo aumento do consumo nacional; isto descreve o quão promissora é a área devido à sua grande potencialidade quanto ao desenvolvimento de novos produtos e tecnologias; como exemplo disto existe a possibilidade de mistura entre materiais lignocelulósicos e os diversos resíduos produzidos pela sociedade. Entre tais resíduos o plástico é o que apresenta maior abundância nos descartes domésticos. Neste contexto, o presente trabalho objetivou determinar propriedades físicas de paineis aglomerados homogêneos confeccionados com partículas de madeira de Eucalyptus sp e Pinus sp e de embalagens de película de polipropileno biorientado tendo, como adesivo, a resina poliuretana à base de óleo de mamona. Foram avaliadas as propriedades: inchamento em espessura e absorção de água, com corpo de prova com e sem impermeabilização, e massa específica. Concluiu-se que, dos fatores investigados, apenas o uso do impermeabilizante foi significativo. De acordo com a ANSI A208.1 (ANS, 1999 os paineis produzidos são classificados como de alta massa específica (H. Relativamente ao inchamento em espessura por 2 h, os paineis atenderam ao exigido pela NBR 14810 (ABNT, 2013 para espessura de 8 a 13 mm.

  16. A sycamore cell wall polysaccharide and a chemically related tomato leaf polysaccharide possess similar proteinase inhibitor-inducing activities.

    Science.gov (United States)

    Ryan, C A; Bishop, P; Pearce, G

    1981-09-01

    A large pectic polysaccharide, called rhamnogalacturonan I, that is solubilized by a fungal endo-alpha-1,4-polygalacturonase from the purified walls of suspension-cultured sycamore cells possesses proteinase inhibitor-inducing activity similar to that of the proteinase inhibitor-inducing factor, a pectic-like oligosaccharide fraction isolated from tomato leaves. This suggests that the proteinase inhibitor-inducing activity resides in particular polysaccharide fragments which can be released when plant cell walls are exposed to appropriate enzyme degradation as a result of either wounding or pest attack.

  17. Structural Basis of Differential Ligand Recognition by Two Classes of bis-(3-5)-cyclic Dimeric Guanosine Monophosphate-binding Riboswitches

    Energy Technology Data Exchange (ETDEWEB)

    K Smith; C Shanahan; E Moore; A Simon; S Strobel

    2011-12-31

    The bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) signaling pathway regulates biofilm formation, virulence, and other processes in many bacterial species and is critical for their survival. Two classes of c-di-GMP-binding riboswitches have been discovered that bind this second messenger with high affinity and regulate diverse downstream genes, underscoring the importance of RNA receptors in this pathway. We have solved the structure of a c-di-GMP-II riboswitch, which reveals that the ligand is bound as part of a triplex formed with a pseudoknot. The structure also shows that the guanine bases of c-di-GMP are recognized through noncanonical pairings and that the phosphodiester backbone is not contacted by the RNA. Recognition is quite different from that observed in the c-di-GMP-I riboswitch, demonstrating that at least two independent solutions for RNA second messenger binding have evolved. We exploited these differences to design a c-di-GMP analog that selectively binds the c-di-GMP-II aptamer over the c-di-GMP-I RNA. There are several bacterial species that contain both types of riboswitches, and this approach holds promise as an important tool for targeting one riboswitch, and thus one gene, over another in a selective fashion.

  18. The Cyclic AMP-Vfr Signaling Pathway in Pseudomonas aeruginosa Is Inhibited by Cyclic Di-GMP

    DEFF Research Database (Denmark)

    Almblad, Henrik; Harrison, Joe J; Rybtke, Morten;

    2015-01-01

    as a direct result of elevated c-di-GMP content. Overproduction of c-di-GMP causes a decrease in the transcription of virulence factor genes that are regulated by the global virulence regulator Vfr. The low level of Vfr-dependent transcription is caused by a low level of its coactivator, cyclic AMP (c...

  19. Stimulation of innate immunity by in vivo cyclic di-GMP synthesis using adenovirus.

    Science.gov (United States)

    Koestler, Benjamin J; Seregin, Sergey S; Rastall, David P W; Aldhamen, Yasser A; Godbehere, Sarah; Amalfitano, Andrea; Waters, Christopher M

    2014-11-01

    The bacterial second messenger cyclic di-GMP (c-di-GMP) stimulates inflammation by initiating innate immune cell recruitment and triggering the release of proinflammatory cytokines and chemokines. These properties make c-di-GMP a promising candidate for use as a vaccine adjuvant, and numerous studies have demonstrated that administration of purified c-di-GMP with different antigens increases protection against infection in animal models. Here, we have developed a novel approach to produce c-di-GMP inside host cells as an adjuvant to exploit a host-pathogen interaction and initiate an innate immune response. We have demonstrated that c-di-GMP can be synthesized in vivo by transducing a diguanylate cyclase (DGC) gene into mammalian cells using an adenovirus serotype 5 (Ad5) vector. Expression of DGC led to the production of c-di-GMP in vitro and in vivo, and this was able to alter proinflammatory gene expression in murine tissues and increase the secretion of numerous cytokines and chemokines when administered to animals. Furthermore, coexpression of DGC modestly increased T-cell responses to a Clostridium difficile antigen expressed from an adenovirus vaccine, although no significant differences in antibody titers were observed. This adenovirus c-di-GMP delivery system offers a novel method to administer c-di-GMP as an adjuvant to stimulate innate immunity during vaccination.

  20. Liposomes loaded with a STING pathway ligand, cyclic di-GMP, enhance cancer immunotherapy against metastatic melanoma.

    Science.gov (United States)

    Nakamura, Takashi; Miyabe, Hiroko; Hyodo, Mamoru; Sato, Yusuke; Hayakawa, Yoshihiro; Harashima, Hideyoshi

    2015-10-28

    Malignant melanomas escape immunosurveillance via the loss/down-regulation of MHC-I expression. Natural killer (NK) cells have the potential to function as essential effector cells for eliminating melanomas. Cyclic di-GMP (c-di-GMP), a ligand of the stimulator of interferon genes (STING) signal pathway, can be thought of as a new class of adjuvant against cancer. However, it is yet to be tested, because technologies for delivering c-di-GMP to the cytosol are required. Herein, we report that c-di-GMP efficiently activates NK cells and induces antitumor effects against malignant melanomas when loaded in YSK05 lipid containing liposomes, by assisting in the efficient delivery of c-di-GMP to the cytosol. The intravenous administration of c-di-GMP encapsulated within YSK05-liposomes (c-di-GMP/YSK05-Lip) into mice efficiently induced the production of type I interferon (IFN) as well as the activation of NK cells, resulting in a significant antitumor effect in a lung metastasis mouse model using B16-F10. This antitumor effect was dominated by NK cells. The infiltration of NK cells was observed in the lungs with B16-F10 melanomas. These findings indicate that the c-di-GMP/YSK05-Lip induces MHC-I non-restricted antitumor immunity mediated by NK cells. Consequently, c-di-GMP/YSK05-Lip represents a potentially new adjuvant system for use in immunotherapy against malignant melanomas.

  1. Extracellular acidic polysaccharide production by a two-membered bacterial coculture.

    Science.gov (United States)

    Kurata, Shinya; Yamada, Kazutaka; Takatsu, Kyoko; Hanada, Satoshi; Koyama, Osamu; Yokomaku, Toyokazu; Kamagata, Yoichi; Kanagawa, Takahiro; Kurane, Ryuichiro

    2003-01-01

    A two-membered coculture of strains KYM-7 and KYM-8, identified as Cellulomonas cellulans and Agrobacterium tumefaciens, respectively, produced a large amount of an extracellular polysaccharide, designated APK-78, from starch. Each strain in pure culture produced only very little amount of polysaccharide from starch; the coexistence of the two strains from the early stage of cultivation was indispensable for a large amount of polysaccharide to be produced. The polysaccharide APK-78 was acidic and composed of glucose, galactose, succinic acid, and pyruvic acid with a molar ratio of 8.1:1.0:1.7:1.0, indicating that it is a succinoglycan type of polysaccharide.

  2. Pivotal roles of the outer membrane polysaccharide export and polysaccharide copolymerase protein families in export of extracellular polysaccharides in gram-negative bacteria.

    Science.gov (United States)

    Cuthbertson, Leslie; Mainprize, Iain L; Naismith, James H; Whitfield, Chris

    2009-03-01

    Many bacteria export extracellular polysaccharides (EPS) and capsular polysaccharides (CPS). These polymers exhibit remarkably diverse structures and play important roles in the biology of free-living, commensal, and pathogenic bacteria. EPS and CPS production represents a major challenge because these high-molecular-weight hydrophilic polymers must be assembled and exported in a process spanning the envelope, without compromising the essential barrier properties of the envelope. Emerging evidence points to the existence of molecular scaffolds that perform these critical polymer-trafficking functions. Two major pathways with different polymer biosynthesis strategies are involved in the assembly of most EPS/CPS: the Wzy-dependent and ATP-binding cassette (ABC) transporter-dependent pathways. They converge in an outer membrane export step mediated by a member of the outer membrane auxiliary (OMA) protein family. OMA proteins form outer membrane efflux channels for the polymers, and here we propose the revised name outer membrane polysaccharide export (OPX) proteins. Proteins in the polysaccharide copolymerase (PCP) family have been implicated in several aspects of polymer biogenesis, but there is unequivocal evidence for some systems that PCP and OPX proteins interact to form a trans-envelope scaffold for polymer export. Understanding of the precise functions of the OPX and PCP proteins has been advanced by recent findings from biochemistry and structural biology approaches and by parallel studies of other macromolecular trafficking events. Phylogenetic analyses reported here also contribute important new insight into the distribution, structural relationships, and function of the OPX and PCP proteins. This review is intended as an update on progress in this important area of microbial cell biology.

  3. Ultrasound assisted extraction of polysaccharides from hazelnut skin.

    Science.gov (United States)

    Yılmaz, Tuncay; Tavman, Şebnem

    2016-03-01

    In this study ultrasound assisted extraction (UAE) of polysaccharides from hazelnut skin has been studied. Optimum sonication time has been evaluated depending on responses such as amount of carbohydrate and dried sample and thermogravimetric analysis. Chemical and structural properties of extracted material have been determined by Fourier transform spectroscopy attenuated-total reflectance (FTIR-ATR) spectroscopy. Pretreated hazelnut skin powders were extracted in distilled water. Mixture was sonicated by ultrasonic processor probe for 15, 30, 45, 60, 90, and 120 min. The results of UAE showed that maximum ethanol insoluble extracts in 60 min and the highest dry matter content could be obtained in 120 min extraction. Although total carbohydrate content of ethanol insoluble dry extract decreased with time, total carbohydrate in ethanol soluble fraction increased. Polysaccharides extracted from hazelnut skin were assumed to be pectic polysaccharide according to the literature survey of FTIR analysis result. Application time of UAE has an important effect on extraction of polysaccharide from hazelnut skin. This affect could be summarized by enhancing extraction yield up to critical level. Decrease of the yield in ethanol insoluble part could be explained by polymer decomposition. Most suitable model was hyperbolic model by having the lowest root mean square error and the highest R(2) values.

  4. Downstream processing of polysaccharide degrading enzymes by affinity chromatography.

    NARCIS (Netherlands)

    Somers, W.A.C.

    1992-01-01

    The objective of this study was the development of affinity matrices to isolate and purify a number of polysaccharide degrading enzymes and the application of these adsorbents in the large- scale purification of the enzymes from fermentation broths. Affinity adsorbents were developed for endo-polyga

  5. Structure of pectic polysaccharides from sunflower salts-soluble fraction

    Science.gov (United States)

    The manuscript discusses the structural features of pectin polysaccharides extracted from seedless sunflower head residues. The analysis using 1H, 13C and two-dimensional gHSQC NMR showed various numbers of methyl and hydroxyl groups attached to the anomeric carbons in the pectin backbone at differe...

  6. Interpenetrating polymer network hydrogels based on polysaccharides for biomedical applications

    NARCIS (Netherlands)

    Pescosolido, L.

    2011-01-01

    The main theme of this thesis is the development and the characterization of interpenetrating polymer network hydrogels (IPNs) based on biodegradable and biocompatible polysaccharides, in particular alginate, hyaluronic acid and dextran. The suitability of these novel systems as pharmaceutical and b

  7. [Optimum of polysaccharide distillation on scrap Cordyceps militaris medium].

    Science.gov (United States)

    Ren, Shu-Yu; Zhao, Chun-Yan; Song, Hui-Yi; Zhao, Hao-Lu; Sun, Jun-De

    2008-03-01

    A mass of scrap Cordyceps militaris solid culture medium could not be utilized better. In this test, using orthogonal design the optimal technique parmeter of extracting polysaccharide was 80 degrees C, two times, in twenty times of water, and 120 minutes each time. Temperature was the most important factor. The referenced data could be provided to depurative production of Cordyceps militaris and resource utilization.

  8. Pectin, a versatile polysaccharide present in plant cell walls

    NARCIS (Netherlands)

    Voragen, A.G.J.; Coenen, G.J.; Verhoef, R.P.; Schols, H.A.

    2009-01-01

    Pectin or pectic substances are collective names for a group of closely associated polysaccharides present in plant cell walls where they contribute to complex physiological processes like cell growth and cell differentiation and so determine the integrity and rigidity of plant tissue. They also pla

  9. Aspergillus enzymes involved in degradation of plant cell wall polysaccharides

    NARCIS (Netherlands)

    Vries, de R.P.; Visser, J.

    2001-01-01

    Degradation of plant cell wall polysaccharides is of major importance in the food and feed, beverage, textile, and paper and pulp industries, as well as in several other industrial production processes. Enzymatic degradation of these polymers has received attention for many years and is becoming a m

  10. Immunological and biochemical characterization of extracellular polysaccharides of mucoralean moulds.

    NARCIS (Netherlands)

    Ruiter, de G.A.

    1993-01-01

    In this thesis the characterization is described of the antigenic determinants (epitopes) of the extracellular polysaccharides (EPSs) from moulds belonging to the order of Mucorales. Detailed knowledge of the structure of these epitopes allows for further development of a new generation of methods f

  11. Microwave superheated water extraction of polysaccharides from spent coffee grounds.

    Science.gov (United States)

    Passos, Cláudia P; Coimbra, Manuel A

    2013-04-15

    The spent coffee grounds (SCG) are a food industry by-product that can be used as a rich source of polysaccharides. In the present work, the feasibility of microwave superheated water extraction of polysaccharides from SCG was studied. Different ratios of mass of SCG to water, from 1:30 to 1:5 (g:mL) were used for a total volume of 80 mL. Although the amount of material extracted/batch (MAE1) increased with the increase of the concentration of the sample, the amount of polysaccharides achieved a maximum of 0.57 g/batch for 1:10. Glycosidic-linkage composition showed that all extraction conditions allowed to obtain mainly arabinogalactans. When the unextracted insoluble material was re-extracted under the same conditions (MAE2), a further extraction of polysaccharides was observed (0.34 g/batch for 1:10), mainly galactomannans. Also, a high amount of oligosaccharides, mainly derived from galactomannans, can be obtained in MAE2 (0.96 g/batch for 1:10). This technology allows to obtain galactomannans and arabinogalactans in proportions that are dependent on the operating conditions.

  12. Immunization of immunosuppressed patients with pneumococcal polysaccharide vaccine

    Energy Technology Data Exchange (ETDEWEB)

    Ammann, A.J.; Schiffman, G.; Addiego, J.E.; Wara, W.M.; Wara, D.W.

    The antibody response after immunization with capsular polysaccharides of Streptococcus pneumoniae of patients with Hodgkin's disease or with carcinoma of the head and neck was studied. Patients with Hodgkin's disease who were immunized prior to the institution of immunosuppressive therapy were capable of responding to each of the pneumococcal polysaccharides evaluated. The level of antibody achieved by the patients is lower than that of normal control subjects. Nevertheless, absolute values were in the range that would be expected to result in protection. The duration of antibody response was not evaluated. Patients with carcinoma of the head and neck did not demonstrate a significant increase in antibody levels after vaccination, which was done at the time of radiation therapy. Two years after immunization antibody levels were lower with recovery at three years. However, these changes were not statistically significant. Decreased levels of antibody to pneumococcal polysaccharide types not present in the vaccine were observed. Studies of patients with carcinoma of the heat and neck demonstrated that radiation therapy has a profound immunosuppressive effect on antibody levels. More selective immunosuppressive therapy and/or an increase in the immunogenicity of the polysaccharides in the vaccine are required for protection of patients with malignancy.

  13. Galactosaminogalactan, a new immunosuppressive polysaccharide of Aspergillus fumigatus.

    Directory of Open Access Journals (Sweden)

    Thierry Fontaine

    2011-11-01

    Full Text Available A new polysaccharide secreted by the human opportunistic fungal pathogen Aspergillus fumigatus has been characterized. Carbohydrate analysis using specific chemical degradations, mass spectrometry, ¹H and ¹³C nuclear magnetic resonance showed that this polysaccharide is a linear heterogeneous galactosaminogalactan composed of α1-4 linked galactose and α1-4 linked N-acetylgalactosamine residues where both monosacharides are randomly distributed and where the percentage of galactose per chain varied from 15 to 60%. This polysaccharide is antigenic and is recognized by a majority of the human population irrespectively of the occurrence of an Aspergillus infection. GalNAc oligosaccharides are an essential epitope of the galactosaminogalactan that explains the universal antibody reaction due to cross reactivity with other antigenic molecules containing GalNAc stretches such as the N-glycans of Campylobacter jejuni. The galactosaminogalactan has no protective effect during Aspergillus infections. Most importantly, the polysaccharide promotes fungal development in immunocompetent mice due to its immunosuppressive activity associated with disminished neutrophil infiltrates.

  14. Catalytic synthesis of sulfated polysaccharides I: Characterization of chemical structure.

    Science.gov (United States)

    Wang, Junlong; Yang, Wen; Yang, Ting; Zhang, Xiaonuo; Zuo, Yuan; Tian, Jia; Yao, Jian; Zhang, Ji; Lei, Ziqiang

    2015-03-01

    In the present study, sulfated derivatives of Artemisia sphaerocephala polysaccharide (SASP) with high degree of substitution (DS) were synthesized by using 4-dimethylaminopyridine (DMAP)/dimethylcyclohexylcarbodiimide (DCC) as catalyst in homogeneous conditions. It was found that DMAP/DCC showed marked improvement in DS of sulfated samples. Compared to sulfated derivatives without catalyst, the DS of SASP increased from 0.91 to 1.28 with an increment in dosage of DMAP from 0 to 10 mg. The influence of DMAP/DCC on the DS of sulfated derivatives was depended on the content of DMAP. The effect of DMAP might be due to its strong coordination to the hydroxy group. The results of FT-IR and X-ray photoelectron spectroscopy (XPS) indicated that SO3- group (S6+, binding energy of 172.3 eV) was widely present in sulfated polysaccharide molecules. 13C NMR results indicated that C-6 substitution was predominant for sulfated polysaccharide when compared with other positions. In the sulfation reaction, a sharp decrease in MW was observed. DMAP/DCC was an effective catalyst system in sulfated modification of polysaccharide.

  15. Extraction, Characterization and Immunological Activity of Polysaccharides from Rhizoma gastrodiae

    Directory of Open Access Journals (Sweden)

    Juncheng Chen

    2016-06-01

    Full Text Available A response surface and Box-Behnken design approach was applied to augment polysaccharide extraction from the residue of Rhizoma gastrodiae. Statistical analysis revealed that the linear and quadratic terms for three variables during extraction exhibited obvious effects on extraction yield. The optimum conditions were determined to be a liquid-to-solid ratio of 54 mL/g, an extraction temperature of 74 °C, an extraction time of 66 min, and three extractions. These conditions resulted in a maximum Rhizoma gastrodiae polysaccharide (RGP extraction yield of 6.11% ± 0.13%. Two homogeneous polysaccharides (RGP-1a and RGP-1b were obtained using DEAE cellulose-52 and Sephadex G-100 columns. The preliminary characterization of RGP-1a and RGP-1b was performed using HPLC-RID, HPGPC, and FTIR. Tests of the immunological activity in vitro showed that the two polysaccharides could significantly stimulate macrophages to release NO and enhance phagocytosis in a dose-dependent manner. In particular, RGP-1b (200 μg/mL and LPS (2 μg/mL had almost the same influence on the NO production and phagocytic activity of RAW 264.7 macrophages (p > 0.05. All the data obtained indicate that RGP-1a and RGP-1b have the potential to be developed as a health food.

  16. FTIR characterization of protein-polysaccharide interactions in extruded blends.

    Science.gov (United States)

    Guerrero, Pedro; Kerry, Joe P; de la Caba, Koro

    2014-10-13

    Soy protein-based blends were processed by double screw extrusion and the effects of different types and contents of polysaccharides were analyzed. Although extrusion has not been widely used for this type of blends, in this study it was observed that the increase in polysaccharide content in blends caused a decrease in specific mechanical energy (SME), facilitating extrusion process and showing the potential of this process, which is more cost effective at industrial scale. In order to explain this behavior, infrared spectroscopy analysis was carried out, mainly in the amide I and II regions. Moreover, curve fitting analysis showed the conformational changes produced in the blends due to the addition of polysaccharides, which affected protein denaturation. These changes also affected properties such as moisture content (MC) and total solubility matter (TSM). However, conformational changes did not show significant effects with respect to piece density (PD) or in the expansion ratio (ER) of the pellets. The quantitative analysis of the changes in the amide I and II regions provided novel information about the modifications produced in protein-based blends modified with polysaccharides. In this context, infrared spectroscopy provided a convenient and powerful means to monitor interactions between all ingredients used in the blend formulation, which is of great importance in order to explain changes in the functional properties of biodegradable materials used for industrial applications in food and pharmaceutical industries.

  17. Mapping the polysaccharide degradation potential of Aspergillus niger

    NARCIS (Netherlands)

    Andersen, M.R.; Giese, M.; De Vries, R.P.; Nielsen, J.

    2012-01-01

    Background The degradation of plant materials by enzymes is an industry of increasing importance. For sustainable production of second generation biofuels and other products of industrial biotechnology, efficient degradation of non-edible plant polysaccharides such as hemicellulose is required. For

  18. Extraction, Characterization and Immunological Activity of Polysaccharides from Rhizoma gastrodiae.

    Science.gov (United States)

    Chen, Juncheng; Tian, Shan; Shu, Xiaoying; Du, Hongtao; Li, Na; Wang, Junru

    2016-06-25

    A response surface and Box-Behnken design approach was applied to augment polysaccharide extraction from the residue of Rhizoma gastrodiae. Statistical analysis revealed that the linear and quadratic terms for three variables during extraction exhibited obvious effects on extraction yield. The optimum conditions were determined to be a liquid-to-solid ratio of 54 mL/g, an extraction temperature of 74 °C, an extraction time of 66 min, and three extractions. These conditions resulted in a maximum Rhizoma gastrodiae polysaccharide (RGP) extraction yield of 6.11% ± 0.13%. Two homogeneous polysaccharides (RGP-1a and RGP-1b) were obtained using DEAE cellulose-52 and Sephadex G-100 columns. The preliminary characterization of RGP-1a and RGP-1b was performed using HPLC-RID, HPGPC, and FTIR. Tests of the immunological activity in vitro showed that the two polysaccharides could significantly stimulate macrophages to release NO and enhance phagocytosis in a dose-dependent manner. In particular, RGP-1b (200 μg/mL) and LPS (2 μg/mL) had almost the same influence on the NO production and phagocytic activity of RAW 264.7 macrophages (p > 0.05). All the data obtained indicate that RGP-1a and RGP-1b have the potential to be developed as a health food.

  19. Thermal decomposition of natural polysaccharides: Chitin and chitosan

    Directory of Open Access Journals (Sweden)

    Kuchina Yu.A.

    2015-03-01

    Full Text Available The results of the thermal analysis of shrimp’s chitin and chitosan have been presented (samples of polysaccharide differed by the deacetylation degree have been studied. The thermal analysis has been carried out by differential thermogravimetry and differential scanning calorimetry. Activation energy of process of chitin and chitosan thermal destruction has been calculated

  20. The digestion of yeast cell wall polysaccharides in veal calves

    NARCIS (Netherlands)

    Gaillard, B.D.E.; Weerden, van E.J.

    1976-01-01

    1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their ‘normal’, milk-substitute (all-milk-prote

  1. Polysaccharide Colloids as Smart Vehicles in Cancer Therapy.

    Science.gov (United States)

    Caro, Carlos; Pozo, David

    2015-01-01

    Cancer disease is one of the leading causes of morbidity and mortality worldwide, with approximately 14 million new cases and around 8 million cancer-related deaths yearly. Estimates expect to increase these figures over the next few years. Therefore, it is very important to develop more effective and targeted therapies. Polysaccharides are widely used for biomedical and pharmaceutical applications due to their interesting properties, and can be utilised in the production of nanovehicles for drug delivery, since they frequently extend the half-life and improve the stability of chemotherapeutic agents in bloodstream allowing them to reach the tumour tissue. Moreover, polysaccharide-based nanovehicles are generally expected to increase the therapeutic benefit by reducing the undesired side effects and promoting a more efficient cellular uptake. Here, we highlight the application of various polysaccharides as nanovehicles in cancer therapy, focusing mainly on in vivo applications and describing the main advantages of each designed system in a critical way. The use of different polysaccharides interacting with metal nanoparticles to develop new nanovehicles for cancer therapy will also be discussed.

  2. Synthesis of Oligosaccharide Fragments of the Pectic Polysaccharide Rhamnogalacturonan I

    DEFF Research Database (Denmark)

    Zakharova, Alexandra

    Pectin is a highly heterogeneous polysaccharide of plant origin. It is found in the primary cell wall and contributes to various cell functions, including support, defense, signaling, and cell adhesion. Pectin also plays important role as a food additive, serving as stabilizing and thickening age...

  3. Pleurotus tuber-regium Polysaccharides Attenuate Hyperglycemia and Oxidative Stress in Experimental Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Hui-Yu Huang

    2012-01-01

    Full Text Available Pleurotus tuber-regium contains polysaccharides that are responsible for pharmacological actions, and medicinal effects of these polysaccharides have not yet been studied in diabetic rats. We examined the antidiabetic, antihyperlipidemic, and antioxidant properties of P. tuber-regium polysaccharides in experimental diabetic rats. Forty rats were equally assigned as diabetic high-fat (DHF diet and polysaccharides treated DHF groups (DHF+1P, DHF+2P, and DHF+3P, 20 mg/kg bodyweight/8-week. Diabetes was induced by chronic low-dose streptozotocin injections and a high-fat diet to mimic type 2 diabetes. Polysaccharides (1P, 2P, and 3P were extracted from three different strains of P. tuber-regium. Fasting blood glucose and glycosylated hemoglobin (HbA1c levels substantially decreased, while serum insulin levels were restored by polysaccharides treatment compared to DHF. Furthermore, plasma total cholesterol, triglycerides, and low-density lipoprotein levels were significantly (P<0.01 lower in polysaccharide groups. High-density lipoprotein levels were attenuated with polysaccharides against diabetes condition. Polysaccharides inhibited (P<0.01 the lipid peroxidation index (malondialdehyde, and restored superoxide dismutase and glutathione peroxidase activities in the liver of diabetic rats. The antihyperglycemic property of polysaccharides perhaps boosts the antioxidant system that attenuates oxidative stress. We emphasize that P. tuber-regium polysaccharides can be considered as an alternative medicine to treat hyperglycemia and oxidative stress in diabetic rats.

  4. In vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis.

    Science.gov (United States)

    Chen, Mei-Zhen; Xie, Hao-Gui; Yang, La-Wei; Liao, Zao-Hui; Yu, Jie

    2010-10-01

    In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides (PGL), Gracilaria lemaneiformis polysaccharide fraction-1 (GL-1), Gracilaria lemaneiformis polysaccharide fraction-2 (GL-2) and Gracilaria lemaneiformis polysaccharide fraction-3 (GL-3) were studied by the Methyl thiazolyl tetrazolium (MTT) method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect (CPE) on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit (PFU), MTT and CPE methods. The results showed: i) Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii) Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides (PGL and GL-2) both of which exhibited higher antiviral activity; iii) A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions.

  5. Comparison of antioxidant and antiproliferation activities of polysaccharides from eight species of medicinal mushrooms.

    Science.gov (United States)

    Chen, Peiying; Yong, Yangyang; Gu, Yifan; Wang, Zeliang; Zhang, Shizhu; Lu, Ling

    2015-01-01

    Polysaccharides from mushrooms including Pleurotus eryngii, P. ostreatus, P. nebrodensis, Lentinus edodes, Hypsizygus marmoreus, Flammulina velutipes, Ganoderma lucidum, and Hericium erinaceus were isolated by water extraction and alcohol precipitation. Our results suggest that all tested polysaccharides have the significant antioxidant capacities of scavenging free radicals (1,1-diphenyl-2-picrylhydrazyl and hydroxyl radicals). Among them, the H. erinaceus polysaccharide exhibits the highest 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity, whereas the L. edodes polysaccharide shows the strongest scavenging ability for hydroxyl radicals. Furthermore, using the MCF-7 breast cancer cell line and HeLa cells, all 8 selected polysaccharides are able to inhibit the proliferation of tumor cells, but the strength of inhibition varied depending on the mushroom species and the concentration used. Notably, G. lucidum polysaccharide shows the highest inhibition activity on MCF-7 cells. By comparison, H. erinaceus polysaccharide has the strongest inhibitory effect on HeLa cells. Moreover, high-performance liquid chromatography with a carbohydrate analysis column showed significant differences in polysaccharide components among these mushrooms. Thus our data suggest that the different species of mushrooms have the variable functions because of their own specific polysaccharide components. The 8 mushroom polysaccharides have the potential to be used as valuable functional food additives or sources of therapeutic agents for antioxidant and cancer treatments, especially polysaccharides from H. erinaceus, L. edodes, and G. lucidum.

  6. Proteomic analysis of scallop hepatopancreatic extract provides insights into marine polysaccharide digestion

    Science.gov (United States)

    Lyu, Qianqian; Jiao, Wenqian; Zhang, Keke; Bao, Zhenmin; Wang, Shi; Liu, Weizhi

    2016-01-01

    Marine polysaccharides are used in a variety of applications, and the enzymes that degrade these polysaccharides are of increasing interest. The main food source of herbivorous marine mollusks is seaweed, and several polysaccharide-degrading enzymes have been extracted from mollusk digestive glands (hepatopancreases). Here, we used a comprehensive proteomic approach to examine the hepatopancreatic proteins of the Zhikong scallop (Chlamys farreri). We identified 435 proteins, the majority of which were lysosomal enzymes and carbohydrate and protein metabolism enzymes. However, several new enzymes related to polysaccharide metabolism were also identified. Phylogenetic and structural analyses of these enzymes suggest that these polysaccharide-degrading enzymes may have a variety of potential substrate specificities. Taken together, our study characterizes several novel polysaccharide-degrading enzymes in the scallop hepatopancreas and provides an enhanced view of these enzymes and a greater understanding of marine polysaccharide digestion. PMID:27982037

  7. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing

    DEFF Research Database (Denmark)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William George Tycho

    2014-01-01

    -cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide......Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non...... localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being...

  8. Characterization of polysaccharides with marked inhibitory effect on lipid accumulation in Pleurotus eryngii.

    Science.gov (United States)

    Chen, Jingjing; Yong, Yangyang; Xing, Meichun; Gu, Yifan; Zhang, Zhao; Zhang, Shizhu; Lu, Ling

    2013-09-12

    Mushrooms have a great potential for the production of useful bioactive metabolites. To explore the bioactive compounds from edible mushrooms for interfering with the development of macrophage-derived foam cells, which is recognized as the hallmark of early atherosclerosis, eight types of mushrooms polysaccharides had been selected to be tested. Consequently, different mushrooms polysaccharides displayed diverse component profiles. Of polysaccharides that we tested, the Pleurotus eryngii polysaccharide had the strongest inhibitory effect on lipid accumulation. Furthermore, through fractionation of DEAE-52 and Sephadex G-100, the polysaccharide from P. eryngii had been successfully purified and identified. By the analysis of IR, GC, and HPLC, the purified polysaccharide was estimated to be 30-38 kDa for the average molecular weight with the monosaccharide composition mainly composed of D-types of mannose, glucose and galactose. Findings presented in this report firstly provide direct evidence, which links the purified polysaccharide moiety with the biological function in foam-cell model.

  9. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing

    DEFF Research Database (Denmark)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William George Tycho;

    2014-01-01

    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non......-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide...... localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being...

  10. Systematic Identification of Cyclic-di-GMP Binding Proteins in Vibrio cholerae Reveals a Novel Class of Cyclic-di-GMP-Binding ATPases Associated with Type II Secretion Systems.

    Science.gov (United States)

    Roelofs, Kevin G; Jones, Christopher J; Helman, Sarah R; Shang, Xiaoran; Orr, Mona W; Goodson, Jonathan R; Galperin, Michael Y; Yildiz, Fitnat H; Lee, Vincent T

    2015-10-01

    Cyclic-di-GMP (c-di-GMP) is a ubiquitous bacterial signaling molecule that regulates a variety of complex processes through a diverse set of c-di-GMP receptor proteins. We have utilized a systematic approach to identify c-di-GMP receptors from the pathogen Vibrio cholerae using the Differential Radial Capillary Action of Ligand Assay (DRaCALA). The DRaCALA screen identified a majority of known c-di-GMP binding proteins in V. cholerae and revealed a novel c-di-GMP binding protein, MshE (VC0405), an ATPase associated with the mannose sensitive hemagglutinin (MSHA) type IV pilus. The known c-di-GMP binding proteins identified by DRaCALA include diguanylate cyclases, phosphodiesterases, PilZ domain proteins and transcription factors VpsT and VpsR, indicating that the DRaCALA-based screen of open reading frame libraries is a feasible approach to uncover novel receptors of small molecule ligands. Since MshE lacks the canonical c-di-GMP-binding motifs, a truncation analysis was utilized to locate the c-di-GMP binding activity to the N-terminal T2SSE_N domain. Alignment of MshE homologs revealed candidate conserved residues responsible for c-di-GMP binding. Site-directed mutagenesis of these candidate residues revealed that the Arg9 residue is required for c-di-GMP binding. The ability of c-di-GMP binding to MshE to regulate MSHA dependent processes was evaluated. The R9A allele, in contrast to the wild type MshE, was unable to complement the ΔmshE mutant for the production of extracellular MshA to the cell surface, reduction in flagella swimming motility, attachment to surfaces and formation of biofilms. Testing homologs of MshE for binding to c-di-GMP identified the type II secretion ATPase of Pseudomonas aeruginosa (PA14_29490) as a c-di-GMP receptor, indicating that type II secretion and type IV pili are both regulated by c-di-GMP.

  11. "Traditsii i integratsija" / Ruta Pels

    Index Scriptorium Estoniae

    Pels, Ruta, 1960-

    2001-01-01

    Suurbritannia saadiku residentsis Lucca keskuses Tallinnas avatud kunstinäitusest "Traditsioonid ja integratsioon", kus näeb Eesti kunstnike maale ja Eesti raudtee ajalugu kajastavaid vanu fotosid. Organiseeris La Galerie Passage koostöös briti saatkonnaga Eestis.

  12. Vetshera estonskogo iskusstva / Ruta Pels

    Index Scriptorium Estoniae

    Pels, Ruta, 1960-

    2001-01-01

    Eesti kunsti õhtutest Suurbritannia saadiku residentsis Tallinnnas, partneriks La Galerie Passage. Iga kuu muutuvas kunstikollektsioonis olevatest eesti kunstnike töödest (Rein Tammik, Malle Leis, Sandra Jõgeva jt.)

  13. La maldad genera cuentos de hadas: Análisis de la película de Guillermo del Toro El Laberinto del Fauno

    Directory of Open Access Journals (Sweden)

    Labrador Ben, Julia María

    2011-04-01

    Full Text Available The Labyrinth Of The Faun (2006 by Guillermo del Toro is a film built on two planes that intertwine constantly: the real plane that matches with the 1944 Spanish post-war when a group of military men commanded by Vidal merciless chase the maquis in the area, and the imaginary plane, thought by Ofelia in parallel, as a sort of escape in front of the negative events she is enduring or that surround her life. When the surrounding evilness is extreme, to escape to a world of fantasy becomes a way out in order to survive; anyway it is only a partial solution as the negative reality will burst to a large or lesser extent into this imaginary world and, unfortunately, this will not be avoided. Guillermo del Toro creates a fiction that, even if originated by evilness, adopts a shape closer to the goodness: a fairy tale. Nevertheless, not everything is goodness in this a priori idyllic world.El laberinto del fauno (2006 de Guillermo del Toro es una película con dos planos que se entrecruzan constantemente: el real, que se corresponde con la España de posguerra de 1944, en el que unos militares capitaneados por Vidal persiguen sin piedad a los maquis de la zona, y el imaginario, ideado por Ofelia en paralelo como evasión ante los acontecimientos negativos que vive o que la rodean. Cuando la maldad circundante es extrema, huir a un mundo de fantasía se convierte en una salida para sobrevivir, pero sólo es una solución parcial, porque la realidad negativa irrumpirá con mayor o menor medida en ese mundo imaginario y no siempre se podrá evitar. Guillermo del Toro plantea una ficción que tiene su origen en la maldad, pero adquiere una forma mucho más cercana a lo contrario, un cuento de hadas, sin embargo, no todo va a ser bondad en ese mundo inicialmente idílico.

  14. Protocol per a la implantació d’eines didàctiques virtuals: competències i habilitats adquirides pels estudiants

    Directory of Open Access Journals (Sweden)

    Laura Guitart Tarrés

    2011-06-01

    Full Text Available L’adaptació al nou espai europeu d’educació superior (EEES ha plantejat alguns canvis en l’enfocament de la formació universitària al nostre país. On abans era el docent el protagonista, ara és l’estudiant el que pren el rol d’actor principal de la seva formació, i l’aprenentatge s’orienta cap a una autonomia i reflexió més grans. En aquest escenari, les noves tecnologies ofereixen un ampli ventall d’opcions per millorar els processos formatius. En aquests sentit, el Grup d’Innovació Docent G•IDEA ha participat activament en aquest procés d’adaptació des de ja fa uns quants anys, i ha creat una sèrie de recursos docents digitals que han estat àmpliament provats en diversos ensenyaments de la Facultat d’Economia i Empresa de la Universitat de Barcelona. L’objectiu d’aquest article és presentar el protocol dissenyat per l’equip d’investigadors del G•IDEA per implantar aquestes eines didàctiques (webquestes i exercicis tutoritzats, i també els resultats d’una enquesta de satisfacció sobre les competències i habilitats adquirides pels nostres estudiants en la utilització dels recursos. Els resultats mostren, d’una banda, que no ha estat possible crear un mateix protocol aplicable a tots els recursos, a causa de les diferències en els objectius didàctics de les distintes eines docents implantades. D’altra banda, la valoració que els estudiants fan de la utilització de les eines és molt positiva, tot i que hi ha algunes diferències entre els recursos analitzats. Conèixer la valoració que l’alumnat fa d’aquests recursos permet al grup d’investigadors poder-los millorar i adequar al perfil dels estudiants perquè aquests en puguin treure el màxim profit possible.

  15. Reactor de película líquida descendente para la sulfonación de ésteres metílicos con trióxido de azufre

    OpenAIRE

    Torres Ortega, Jesús Alfonso; Díaz Aldana, Luís Alejandro; Sánchez Castellanos, Francisco José

    2010-01-01

    Se realizó un conjunto de experimentos de sulfonación de dodecilbenceno (DDB) y ésteres metílicos (ME) derivados de la esteari- na hidrogenada de palma, con SO3 gaseoso desorbido del óleum, en un reactor de sulfonación en película líquida descendente a escala banco de 40 cm de longitud y ½ pulgada de diámetro interno. Mediante titulaciones volumétricas se determinaron los porcentajes de materia sulfonada y contenido de ácido sulfúrico, así como el porcentaje de aceite libre mediante e...

  16. Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México

    OpenAIRE

    Javier Alcocer; Elva Escobar; Luis A. Oseguera

    2008-01-01

    El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificaci...

  17. Desenvolvimento e caracterização de matrizes poliméricas como veículo de componentes ativos do extrato etanólico da película de amendoim

    OpenAIRE

    2015-01-01

    A película de amendoim é um resíduo da indústria de alimentos. Esse resíduo é rico em compostos fenólicos como resveratrol e procianidinas e apresenta elevada atividade antioxidante e atividade farmacológica. Apesar de suas atividades farmacológicas, compostos fenólicos apresentam baixa biodisponibilidade devido à glucuronidação catalisada pelas enzimas UDP-glucuronosyltransferases (UGTs), que acontece na primeira passagem no intestino e/ou fígado, dificultando a utilização dos compostos fenó...

  18. La ladrona de libros : Reseña de una película de Brian Percivel sobre un libro de Markus Zusak, USA - Alemania, 20th Century Fox, 2013

    OpenAIRE

    Urtasun, Carolina

    2014-01-01

    “La ladrona de libros”, película de Brian Percivel basada en una novela de Zusak, cuenta la historia de una niña alemana, Liesel, a quien sus padres dejan en adopción antes de huir de la Alemania nazi tiempo antes de la Segunda Guerra Mundial. Liesel es acogida por una pareja de mediana edad, con la que aprende a convivir y a leer. El primer día de clases en la escuela sus compañeros se burlan de ella porque, en lugar de su nombre, escribe apenas unas grandes cruces en el pizarrón. Sin emb...

  19. Aplicación de películas comestibles a base de quitosano y mucílago de nopal en fresa (Fragaria ananassa) almacenada en refrigeración

    OpenAIRE

    Ruiz Hernández, Fabiola

    2009-01-01

    El objetivo del presente trabajo fue realizar un estudio para evaluar la aplicación de películas comestibles a base de quitosano y mucílago de nopal (Opuntia ficus indica) en la calidad de fresas (Fragaria ananassa) variedad "Festival", almacenadas en recipientes plásticos, listas para consumir y almacenadas en refrigeración. La primera etapa del estudio consistió en estandarizar una técnica para la extracción de mucílago de nopal. Se evaluaron varias técnicas reportadas...

  20. "Persecuciones y sacrificios en la película Mexicana Amores perros (2000) de Alejandro González Iñarritu : una lectura de categorías narrativas"

    OpenAIRE

    2008-01-01

    En esta tesina realizamos una lectura tripartita de la película Amores perros y proponemos la hipótesis de una cuarte lectura. Primeramente estudiamos los problemas del secuenciado y temporalización en la lectura sintagmática, y luego las cuestiones de la causalidad versus cronología en la lectura paradigmática, analizando las diferentes secuencias fílmicas. Seguimos las conflictivas relaciones entre lo consecutivo temporal del discurso y lo consecuente lógico de la historia, o sea la dinámic...

  1. Comprehensive overexpression analysis of cyclic-di-GMP signalling proteins in the phytopathogen Pectobacterium atrosepticum reveals diverse effects on motility and virulence phenotypes.

    Science.gov (United States)

    Tan, H; West, J A; Ramsay, J P; Monson, R E; Griffin, J L; Toth, I K; Salmond, G P C

    2014-07-01

    Bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous bacterial signalling molecule produced by diguanylate cyclases of the GGDEF-domain family. Elevated c-di-GMP levels or increased GGDEF protein expression is frequently associated with the onset of sessility and biofilm formation in numerous bacterial species. Conversely, phosphodiesterase-dependent diminution of c-di-GMP levels by EAL- and HD-GYP-domain proteins is often accompanied by increased motility and virulence. In this study, we individually overexpressed 23 predicted GGDEF, EAL or HD-GYP-domain proteins encoded by the phytopathogen Pectobacterium atrosepticum strain SCRI1043. MS-based detection of c-di-GMP and 5'-phosphoguanylyl-(3'-5')-guanosine in these strains revealed that overexpression of most genes promoted modest 1-10-fold changes in cellular levels of c-di-GMP, with the exception of the GGDEF-domain proteins ECA0659 and ECA3374, which induced 1290- and 7660-fold increases, respectively. Overexpression of most EAL domain proteins increased motility, while overexpression of most GGDEF domain proteins reduced motility and increased poly-β-1,6-N-acetyl-glucosamine-dependent flocculation. In contrast to domain-based predictions, overexpression of the EAL protein ECA3549 or the HD-GYP protein ECA3548 increased c-di-GMP concentrations and reduced motility. Most overexpression constructs altered the levels of secreted cellulases, pectinases and proteases, confirming c-di-GMP regulation of virulence in Pe. atrosepticum. However, there was no apparent correlation between virulence-factor induction and the domain class expressed or cellular c-di-GMP levels, suggesting that regulation was in response to specific effectors within the network, rather than total c-di-GMP concentration. Finally, we demonstrated that the cellular localization patterns vary considerably for GGDEF/EAL/HD-GYP proteins, indicating it is a likely factor restricting specific interactions within the c-di-GMP

  2. Extraction, purification and antioxidant activity of polysaccharides from bamboo leaves

    Institute of Scientific and Technical Information of China (English)

    GAO Ya-ni; TIAN Cheng-rui; ZHAO Li-li

    2012-01-01

    Ultrasonic extraction (UE) was employed for the extraction of bamboo leaf polysaccharides (BLP).The influential parameters of UE procedure including extraction time,ultrasonic power and solid/liquid ratio were optimized by orthogonal experiments.DEAE-cellulose column chromatography was applied to purify BLP and then the radical scavenging activity of BLP was also evaluated.Optimal extraction conditions were:extraction time of 15 min,ultrasonic power of 300 W,and solid/liquid ratio of 1:15.Four kinds of polysaccharides were obtained by DEAE-cellulose column chromatography; the maximum superoxide radical scavenging rate (20.4%) of BLP was inferior to that of vitamin C (Vc,the control) and the hydroxyl radical scavenging rate (50%) was equivalent to that of Vc.

  3. Experience with Salmonella typhi Vi capsular polysaccharide vaccine.

    Science.gov (United States)

    Hessel, L; Debois, H; Fletcher, M; Dumas, R

    1999-09-01

    Typhoid fever remains an important health threat in many parts of the world, with an estimated 16 million cases and 600,000 deaths occurring each year. The emergence of Salmonella typhi strains multiply resistant to antibiotics has complicated the treatment of this disease. Field experience of 8 years shows that a vaccine composed of purified Vi capsular polysaccharide of Salmonella typhi, given as a single intramuscular or deep subcutaneous injection, has consistent immunogenicity and efficacy. Side effects, based on reports since 1989, are infrequent and mild. Furthermore, the Vi vaccine may be administered simultaneously with other common "travel" vaccines, at two different sites of injection, without affecting immunogenicity and tolerability. This review presents an update of the development and clinical experience with the Salmonella typhi Vi polysaccharide vaccine (Typhim Vi; Pasteur Mérieux Connaught, France).

  4. Carbohydrase Systems of Saccharophagus degradans Degrading Marine Complex Polysaccharides

    Directory of Open Access Journals (Sweden)

    Maxim Suvorov

    2011-04-01

    Full Text Available Saccharophagus degradans 2-40 is a γ-subgroup proteobacterium capable of using many of the complex polysaccharides found in the marine environment for growth. To utilize these complex polysaccharides, this bacterium produces a plethora of carbohydrases dedicated to the processing of a carbohydrate class. Aiding in the identification of the contributing genes and enzymes is the known genome sequence for this bacterium. This review catalogs the genes and enzymes of the S. degradans genome that are likely to function in the systems for the utilization of agar, alginate, α- and β-glucans, chitin, mannans, pectins, and xylans and discusses the cell biology and genetics of each system as it functions to transfer carbon back to the bacterium.

  5. Development of drilling fluids based on polysaccharides and natural minerals

    Directory of Open Access Journals (Sweden)

    Zhanar Nurakhmetova

    2016-03-01

    Full Text Available The technology of oil well drilling in complex geological conditions by applying the drilling muds based on the polysaccharides – gellan, xanthan and their mixture which potentially possess a good flocculation properties and the ability to reversible sol-gel transition in dependence of temperature and concentration of low molecular weight cations in water has been justified in this work. For the preparation of drilling muds, gellan and xanthan were used, these polymers were obtained from biomass by an aerobic fermentation using microorganisms Sphingomonas elodea and Xanthomonas campestris. Bentonite was used as a natural mineral. Physical and chemical characteristics of aqueous and aqueous-salt solutions of natural polysaccharide gellan including: density, intrinsic and effective viscosity, static shear stress, dynamic shear stress, sedimentation stability and other parameters were determined while varying polymer compositions and concentrations, ionic strength of the solution, nature of low molecular weight salts, concentration of dispersion phase, pH of the medium and temperature.

  6. Melissotarsus ants are likely able to digest plant polysaccharides.

    Science.gov (United States)

    Mony, Ruth; Dejean, Alain; Bilong, Charles Félix Bilong; Kenne, Martin; Rouland-Lefèvre, Corinne

    2013-10-01

    Melissotarsus ants have an extremely specialized set of behaviours. Both workers and gynes tunnel galleries in their host tree bark. Workers walk with their mesothoracic legs pointing upwards and tend Diaspididae hemiptera for their flesh. The ants use their forelegs to plug the galleries with silk that they secrete themselves. We hypothesised that the ants' energetic needs for nearly constant gallery digging could be satisfied through the absorption of host tree tissues; so, using basic techniques, we examined the digestive capacities of workers from two species. We show that workers are able to degrade oligosaccharides and heterosides as well as, to a lesser degree, polysaccharides. This is one of the rare reports on ants able to digest plant polysaccharides other than starch.

  7. Lytic polysaccharide monooxygenases disrupt the cellulose fibers structure

    Science.gov (United States)

    Villares, Ana; Moreau, Céline; Bennati-Granier, Chloé; Garajova, Sona; Foucat, Loïc; Falourd, Xavier; Saake, Bodo; Berrin, Jean-Guy; Cathala, Bernard

    2017-01-01

    Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that breakdown recalcitrant polysaccharides such as cellulose. Here we investigate the action of LPMOs on cellulose fibers. After enzymatic treatment and dispersion, LPMO-treated fibers show intense fibrillation. Cellulose structure modifications visualized at different scales indicate that LPMO creates nicking points that trigger the disintegration of the cellulose fibrillar structure with rupture of chains and release of elementary nanofibrils. Investigation of LPMO action using solid-state NMR provides direct evidence of modification of accessible and inaccessible surfaces surrounding the crystalline core of the fibrils. The chains breakage likely induces modifications of the cellulose network and weakens fibers cohesion promoting their disruption. Besides the formation of new initiation sites for conventional cellulases, this work provides the first evidence of the direct oxidative action of LPMOs with the mechanical weakening of the cellulose ultrastructure. LPMOs can be viewed as promising biocatalysts for enzymatic modification or degradation of cellulose fibers. PMID:28071716

  8. Ganoderma lucidum Polysaccharide Peptide (GLPP for the Cancer Treatment

    Directory of Open Access Journals (Sweden)

    Imam Rasjidi

    2015-06-01

    Full Text Available Ganoderma lucidum mushroom (also known as Ling Zhi in China, Mannetake /Reishi in Japan has been widely used for thousands of years to prevent and treat various diseases, such as heart disease, diabetes mellitus, viral infection, and cancer. Polysaccharides from Ganoderma lucidum has been extensively investigated for free radical scavenging activity. Both in vivo and in vitro studies suggest that G. lucidum have anti-tumor effects, which mediated by its immunomodulatory, anti-angiogenesis, and cytotoxic effects. Ganoderma lucidum polysaccharide peptide (GLPP which extracted from Ganoderma lucidum mycelium tissue culture, give the best quality of β-D-Glucans bioactive compounds. These biologically active glucans interact with receptors on the surface of immune cells such as macrophage and natural killer cell (NK cell to induce immunomodulatory and tumoricidal effects. However, many studies still need to answer those mechanisms.

  9. LIGHT SCATTERING OF POLYSACCHARIDE FROM LACQUER IN AQUEOUS SOLUTION

    Institute of Scientific and Technical Information of China (English)

    ZHANG Lina; DU Yumin; KUMANOTANI JU

    1989-01-01

    The polysaccharide having weight-average molecular weight Mw= 1. 09 × 105 , isolated from the sap of lac trees ( Vietnam ), was separated into 12 fractions by aqueous-phase preparative gel permeation chromatography. The molecular weights and molecular weight distributions of the fractions were measured in aqueous 0.08M KCl/0.01 M NaAc and 0.4M KCl/0.05M NaAc at pH = 7.6 by light scattering, viscometry and gel permeation chromatography. The Mark-Houwink equation in aqueous 0.08M KCl/0.01M NaAc at30 ℃ was found to be [ η] = 2.28 ×10-2 M0.52w ( cm3/g ), which indicated the polysaccharide chain in the aqueous solution to be a spherical random coil.

  10. Results of the Study of Mutagenic Effects of Microbial Polysaccharides

    Directory of Open Access Journals (Sweden)

    Natalya A. Sidorova

    2016-06-01

    Full Text Available The article presents the results of a study of mutagenic effects of Pseudomonas alcaligenеs polysaccharides. Pseudomonas genus – non-fermentative ubiquitous bacteria, having specific metabolic cycles and unique physical, chemical and biological properties was used as a producer of natural exopolysaccharides. In an experiment using the Ames test, three variants of test compounds were studied: 1. a compound of the Pseudomonas alcaligenes biofilm, 2. exopolysaccharide matrix and the microorganism cell wall compound, and 3. actually the microbial exopolysaccharide. In all cases the lack of mutagen action of polysaccharides of Pseudomonas alcaligenes is proved that make them perspective for use as nanomaterials of new generation – alternative wound coverings.

  11. Development of drilling fluids based on polysaccharides and natural minerals

    OpenAIRE

    Zhanar Nurakhmetova; Iskander Gussenov; Vladimir Sigitov; Sarkyt Kudaibergenov

    2016-01-01

    The technology of oil well drilling in complex geological conditions by applying the drilling muds based on the polysaccharides – gellan, xanthan and their mixture which potentially possess a good flocculation properties and the ability to reversible sol-gel transition in dependence of temperature and concentration of low molecular weight cations in water has been justified in this work. For the preparation of drilling muds, gellan and xanthan were used, these polymers were obtained from b...

  12. Effects of Ganoderma lucidum polysaccharides on diabetic nephropathy in mice

    Institute of Scientific and Technical Information of China (English)

    Chao-yongHE; Zhi-binLIN

    2004-01-01

    AIM: To study the effects of Ganoderma lucidum polysaccharides (GL-PS) on the renal damage in streptozotocin-induced diabetic mice. METHODES: Nine weeks old male C57 BI/6J mice were made diabetes with two or three consecutive intraperitoneal injection of streptozotocin, 72 h later, hyperglycemic mice with glucose levels higher than glucose 300 mg/dL were used. The diabetic mice were randomly divided into three groups and administrated intragastrically with vehicle or Gl-PS (125 mg/

  13. Lubrication, adsorption, and rheology of aqueous polysaccharide solutions.

    Science.gov (United States)

    Stokes, Jason R; Macakova, Lubica; Chojnicka-Paszun, Agnieszka; de Kruif, Cornelis G; de Jongh, Harmen H J

    2011-04-05

    Aqueous lubrication is currently at the forefront of tribological research due to the desire to learn and potentially mimic how nature lubricates biotribological contacts. We focus here on understanding the lubrication properties of naturally occurring polysaccharides in aqueous solution using a combination of tribology, adsorption, and rheology. The polysaccharides include pectin, xanthan gum, gellan, and locus bean gum that are all widely used in food and nonfood applications. They form rheologically complex fluids in aqueous solution that are both shear thinning and elastic, and their normal stress differences at high shear rates are found to be characteristic of semiflexible/rigid molecules. Lubrication is studied using a ball-on-disk tribometer with hydrophobic elastomer surfaces, mimicking biotribological contacts, and the friction coefficient is measured as a function of speed across the boundary, mixed, and hydrodynamic lubrication regimes. The hydrodynamic regime, where the friction coefficient increases with increasing lubricant entrainment speed, is found to depend on the viscosity of the polysaccharide solutions at shear rates of around 10(4) s(-1). The boundary regime, which occurs at the lowest entrainment speeds, depends on the adsorption of polymer to the substrate. In this regime, the friction coefficient for a rough substrate (400 nm rms roughness) is dependent on the dry mass of polymer adsorbed to the surface (obtained from surface plasmon resonance), while for a smooth substrate (10 nm rms roughness) the friction coefficient is strongly dependent on the hydrated wet mass of adsorbed polymer (obtained from quartz crystal microbalance, QCM-D). The mixed regime is dependent on both the adsorbed film properties and lubricant's viscosity at high shear rates. In addition, the entrainment speed where the friction coefficient is a minimum, which corresponds to the transition between the hydrodynamic and mixed regime, correlates linearly with the ratio

  14. High molecular weight polysaccharide that binds and inhibits virus

    Science.gov (United States)

    Konowalchuk, Thomas W

    2014-01-14

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods on inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  15. Complete structure of the polysaccharide from Streptococcus sanguis J22

    Energy Technology Data Exchange (ETDEWEB)

    Abeygunawardana, C.; Bush, C.A. (Illinois Institute of Technology, Chicago (USA)); Cisar, J.O. (National Institute of Dental Research, Bethesda, MD (USA))

    1990-01-09

    The cell wall polysaccharides of certain oral streptococci such as Streptococcus sanguis strains 34 and J22, although immunologically distinct, act as receptors for the fimbrial lectins of Actinomyces viscosus T14V. The authors report the complete covalent structure of the polysaccharide from S. sanguis J22 which is composed of a heptasaccharide subunit linked by phosphodiester bonds. The repeating subunit, which contains {alpha}-GalNAc, {alpha}-rhamnose, {beta}-rhamnose, {beta}-glucose, and {beta}-galactose all in the pyranoside form and {beta}-galactofuranose, is compared with the previously published structure of the polysaccharide from strain 34. The structure has been determined almost exclusively by high-resolution nuclear magnetic resonance methods. The {sup 1}H and {sup 13}C NMR spectra of the polysaccharides from both strains 34 and J22 have been completely assigned. The stereochemistry of pyranosides was assigned from J{sub H-H} values determined from phase-sensitive COSY spectra, and acetamido sugars were assigned by correlation of the resonances of the amide {sup 1}H with the sugar ring protons. The {sup 13}C spectra were assigned by {sup 1}H-detected multiple-quantum correlation (HMQC) spectra, and the assignments were confirmed by {sup 1}H-detected multiple-bond correlation (HMBC) spectra. The positions of the glycosidic linkages were assigned by detection of three-bond {sup 1}H-{sup 13}C correlation across the glycosidic linkage in the HMBC spectra. The positions of the phosphodiester linkages were determined by splittings observed in the {sup 13}C resonances due to {sup 31}P coupling and also by {sup 1}H-detected {sup 31}P correlation spectroscopy.

  16. Effect of Extraction Methods on Polysaccharide of Clitocybe maxima Stipe

    OpenAIRE

    Junchen Chen; Pufu Lai; Hengsheng Shen; Hengguang Zhen; Rutao Fang

    2013-01-01

    Clitocybe maxima (Gartn. ex Mey. Fr.) Quél. is a favorable edible fungi species. The proportion of its stipe is about 45% of entire fruit biomass, which is a low value defined byproduct. To increase its value added utilization, three extraction methods (as hot water, microwave-assisted and complex-enzyme-hydrolysis-assist) were conducted. The extraction effect on the polysaccharide of Clitocybe maxima stipe was compared and the processing conditions in extraction were optimized. The content o...

  17. Mapping the polysaccharide degradation potential of Aspergillus niger

    DEFF Research Database (Denmark)

    Andersen, Mikael Rørdam; Giese, Malene; de Vries, Ronald P.

    2012-01-01

    of 188 genes coding for carbohydrate-active enzymes from Aspergillus niger, thus forming an analysis framework, which can be queried. Combination of this information network with gene expression analysis on mono-and polysaccharide substrates has allowed elucidation of concerted gene expression from...... of carbohydrate-active enzymes. Applying this network-based approach, we provide the first genome-scale characterization of all genes coding for carbohydrate-active enzymes identified in A. niger....

  18. Sulfation patterns determine cellular internalization of heparin-like polysaccharides

    OpenAIRE

    Raman, Karthik; Mencio, Caitlin; Desai, Umesh R.; Kuberan, Balagurunathan

    2013-01-01

    Heparin is a highly sulfated polysaccharide which serves biologically relevant roles as an anticoagulant and anti-cancer agent. While it is well known that modification of heparin’s sulfation pattern can drastically influence its ability to bind growth factors and other extracellular molecules, very little is known about the cellular uptake of heparin and the role sulfation patterns serve in affecting its internalization. In this study, we chemically synthesized several fluorescently-labeled ...

  19. Elaboración, caracterización y comparación de películas comestibles en base a aislado de proteínas de suero lácteo (WPI

    Directory of Open Access Journals (Sweden)

    Rosa Márquez

    2011-05-01

    Full Text Available El incremento del interés en alimentos de alta calidad con mayor vida útil y un menor impacto a nivel ambiental ha llevado al estudio y desarrollo de películas y coberturas comestibles y/o biodegradables. Éstas son una excelente alternativa de empaque de alimentos por su carácter biodegradable, flexible y su poder para actuar como envases activos. En base a esto y a la gran producción lechera en Uruguay, en el presente trabajo se elaboraron y estudiaron películas en base a WPI, como una alternativa de uso de los subproductos de la industria láctea de alto valor agregado. Algunos plastificantes como glicerol y sorbitol modifican las propiedades de las proteínas insertándose dentro de su estructuratridimensional, y utilizados en pequeñas cantidades introducen cambios significativos. El objetivo del presente trabajo fue la elaboración, caracterización y comparación de películas comestibles según sus propiedades mecánicas de tensión. Para ello se utilizaron dos concentraciones distintas de WPI (8 % y 10 % y tres proporciones de WPI/plastificante: 1,6/1; 2,0/1 y 2,3/1. La disminución tanto de la cantidad de proteína como de plastificante en las películas produjo un aumento de las fuerzas y stress máximos y a la ruptura. Las películas más elásticas se obtienen con la mayor cantidad de plastificante estudiada (1,6/1, obteniéndose una elongación de hasta un 60 % con un 8 % de WPI en la película. Las películas realizadas con sorbitol presentan mayores fuerzas y tensiones que las de glicerol, manteniéndose en ambos casos la tendencia a la disminución de dichas propiedades con el aumento de plastificante. La elasticidad aumenta a mayor proporción de cualquiera de los plastificantes estudiados y las películas que contienen glicerol son más elásticas que las que contienen sorbitol.AbstractIncreasing interest in high-quality food products with increased shelf life and reduced environmental impact has encouraged the study and

  20. [Biological activities of exogenous polysaccharides via controlling endogenous proteoglycan metabolism in vascular endothelial cells].

    Science.gov (United States)

    Sato, Tomoko; Yamamoto, Chika; Fujiwara, Yasuyuki; Kaji, Toshiyuki

    2008-05-01

    Proteoglycan contains glycosmainoglycans, which are endogenous sulfated polysaccharides, in the molecule. The metabolism of proteoglycans regulates cell behavior and cellular events. It is possible that exogenous polysaccharide-related molecules exhibit their biological activities by two mechanisms. One is the interaction with cells and the other is the interaction with growth factors/cytokines that regulate proteoglycans. In this review, we describe sodium spirulan, a sulfated polysaccharide obtained from a hot-water extract of the blue-green alga Spirulina platensis, as an exogenous polysaccharide that stimulates the release of proteoglycans from vascular endothelial cells. Factors that regulate endothelial proteoglycan metabolism are also being described as possible target molecules of exogenous polysaccharides. Further research is required to obtain exogenous polysaccharide-related molecules that exhibit useful biological activities through controlling endothelial proteoglycan metabolism for protection against vascular lesions such as atheroslcerosis.

  1. Characterization of polysaccharides extracted from spent coffee grounds by alkali pretreatment.

    Science.gov (United States)

    Ballesteros, Lina F; Cerqueira, Miguel A; Teixeira, José A; Mussatto, Solange I

    2015-01-01

    Spent coffee grounds (SCG), obtained during the processing of coffee powder with hot water to make soluble coffee, are the main coffee industry residues and retain approximately seventy percent of the polysaccharides present in the roasted coffee beans. The purpose of this study was to extract polysaccharides from SCG by using an alkali pretreatment with sodium hydroxide at 25°C, and determine the chemical composition, as well as the antioxidant and antimicrobial properties of the extracted polysaccharides. Galactose (60.27%mol) was the dominant sugar in the recovered polysaccharides, followed by arabinose (19.93%mol), glucose (15.37%mol) and mannose (4.43%mol). SCG polysaccharides were thermostable, and presented a typical carbohydrate pattern. Additionally, they showed good antioxidant activity through different methods and presented high antimicrobial percent inhibition against Phoma violacea and Cladosporium cladosporioides (41.27% and 54.60%, respectively). These findings allow identifying possible applications for these polysaccharides in the food industry.

  2. Thermal stress resistance and aging effects of Panax notoginseng polysaccharides on Caenorhabditis elegans.

    Science.gov (United States)

    Feng, Shiling; Cheng, Haoran; Xu, Zhou; Shen, Shian; Yuan, Ming; Liu, Jing; Ding, Chunbang

    2015-11-01

    Panax notoginseng attract public attention due to their potential biomedical properties and corresponding health benefits. The present study investigated the anti-aging and thermal stress resistance effects of polysaccharides from P. notoginseng on Caenorhabditis elegans. Results showed polysaccharides had little scavenging ability of reactive oxygen species (ROS) in vitro, but significantly extended lifespan of C. elegans, especially the main root polysaccharide (MRP) which prolongs the mean lifespan of wild type worms by 21%. Further study demonstrated that the heat stress resistance effect of polysaccharides on C. elegans might be attributed to the elevation of antioxidant enzyme activities (both superoxide dismutase (SOD) and catalase (CAT)) and the reduction lipid peroxidation of malondialdehyde (MDA) level. Taken together, the results provided a scientific basis for the further exploitation of the mechanism of longer lifespan controlled by P. notoginseng polysaccharides on C. elegans. The P. notoginseng polysaccharides might be considered as a potential source to delay aging.

  3. [Antitumor Activity of Polysaccharides from Ganoderma lucidum Mycelium: in vivo Comparative Study].

    Science.gov (United States)

    Krasnopolskaya, L M; Yarina, M S; Avtonomova, A V; Usov, A I; Isakova, E B; Bukchman, V M

    2015-01-01

    Fractions of water soluble and alkali soluble polysaccharides, as well as fucogalactan, a water soluble polysaccharide, and xylomannan, an alkali soluble polysaccharide, were isolated from the Ganoderma lucidum submerged mycelium. When administered orally, the polysaccharides showed antitumor activity in vivo on murine models of solid tumors. Xylomannan and fucogalactan showed the highest antitumor activity. Sensitivity to xylomannan was more pronounced in adenocarcinoma Ca755 as compared to the T-cell lymphocytic leukemia P388. The antitumor activity of the water soluble polysaccharides total fractions from the mycelium and fruiting bodies of the G. lucidum strain was almost identical. The maximum antitumor effect of the mycelium water soluble polysaccharides total fraction was observed with the use of the daily dose of 2 mg/kg.

  4. Marine Polysaccharides: A Source of Bioactive Molecules for Cell Therapy and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Anne-Marie Fischer

    2011-09-01

    Full Text Available The therapeutic potential of natural bioactive compounds such as polysaccharides, especially glycosaminoglycans, is now well documented, and this activity combined with natural biodiversity will allow the development of a new generation of therapeutics. Advances in our understanding of the biosynthesis, structure and function of complex glycans from mammalian origin have shown the crucial role of this class of molecules to modulate disease processes and the importance of a deeper knowledge of structure-activity relationships. Marine environment offers a tremendous biodiversity and original polysaccharides have been discovered presenting a great chemical diversity that is largely species specific. The study of the biological properties of the polysaccharides from marine eukaryotes and marine prokaryotes revealed that the polysaccharides from the marine environment could provide a valid alternative to traditional polysaccharides such as glycosaminoglycans. Marine polysaccharides present a real potential for natural product drug discovery and for the delivery of new marine derived products for therapeutic applications.

  5. Carboxymethylation of polysaccharide from Cyclocarya paliurus and their characterization and antioxidant properties evaluation.

    Science.gov (United States)

    Wang, Zhi-Jun; Xie, Jian-Hua; Shen, Ming-Yue; Tang, Wei; Wang, Hui; Nie, Shao-Ping; Xie, Ming-Yong

    2016-01-20

    In this study, three chemically carboxymethyl polysaccharides (CM-CPs) were derived from Cyclocarya paliurus polysaccharides. The physicochemical properties and antioxidant activity in vitro of carboxymethyl derivatives were determined. The results of degree of substitution and FT-IR analysis showed the carboxymethylation of polysaccharides were successful. Compared with unmodified polysaccharides, the contents of carbohydrate and protein were decreased while CM-CP3 with highest DS value had more uronic acid. The carboxymethyl derivatives was mainly composed of Ara, Gal, Glc, Man, GalA, with a molecular weight (Mw) of 1.03-1.08 × 10(6)Da. Compared with the native polysaccharide, the CM-CP3 with highest DS and Mw exhibited the highest antioxidant activity in β-carotene-linoleic acid assay. However, the superoxide radical and hydroxyl radical scavenging activity were decreased by CM-CPs. These results demonstrated appropriate carboxymethylation modification could enhance the potential of C. paliurus polysaccharide as oxidation inhibitor.

  6. Translational Medicine Study on Extraction and Determination of Urtica Polysaccharides and Their Anti-Oxidation Effect

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhi-tao; LI Shan-shan; WANG Tong-fang; CHEN Xiao-feng

    2016-01-01

    Objective: Translational medicine study on extraction and determination of urtica polysaccharides and their anti-oxidation effect. Methods: Water-soluble alcohol sedimentation technique was used to extract the urtica polysaccharides, and ultraviolet (UV) spectrophotometry was applied to determine their content. The influence of polysaccharides on the activities of glutathione (GSH), catalase (CAT), malondialdéhyde (MDA) and superoxyde dismutase (SOD) in mice with H22-loaded tumors was observed. Results: The purity of urtica polysaccharides was 61.39% after extraction and puriifcation. After administration of high-, moderate- and low-dose urtica polysaccharides, the activity of serum GSH, CAT and SOD was markedly higher while MDA content was prominently lower in mice with H22-loaded tumors than those in model group. Conclusion: Urtica polysaccharides can strengthen the anti-oxidation effect and inhibit the lipid peroxidation reaction in body.

  7. Sulphation can enhance the antioxidant activity of polysaccharides produced by Enterobacter cloacae Z0206.

    Science.gov (United States)

    Jin, Mingliang; Wang, Youming; Huang, Ming; Lu, Zeqing; Wang, Yizhen

    2014-01-01

    The protective effects of sulfated polysaccharide derivatives produced by Enterobacter cloacae Z0206 against H₂O₂-induced oxidative damage in RAW264.7 murine macrophages as well as the possible mechanisms governing the protective effects were studied. Sulfated polysaccharides protected RAW264.7 cells from oxidative damage and apoptosis induced by H₂O₂ by protecting the cellular structure; improving the activity of antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px); and inhibiting caspase-3 activation and DNA fragmentation. In addition, the sulfated polysaccharides conferred higher levels of protection from H₂O₂-induced oxidative damage in RAW264.7 murine macrophages compared to the native polysaccharide lacking sulfation. These results indicated that sulfated modifications might be an effective approach to enhance the antioxidant activity of polysaccharides produced by E. cloacae Z0206, and the sulfated derivatives of these polysaccharides may act as potent antioxidant agents.

  8. Synthetic polymer nanoparticle-polysaccharide interactions: a systematic study.

    Science.gov (United States)

    Zeng, Zhiyang; Patel, Jiten; Lee, Shih-Hui; McCallum, Monica; Tyagi, Anuradha; Yan, Mingdi; Shea, Kenneth J

    2012-02-08

    The interaction between synthetic polymer nanoparticles (NPs) and biomacromolecules (e.g., proteins, lipids, and polysaccharides) can profoundly influence the NPs fate and function. Polysaccharides (e.g., heparin/heparin sulfate) are a key component of cell surfaces and the extracelluar matrix and play critical roles in many biological processes. We report a systematic investigation of the interaction between synthetic polymer nanoparticles and polysaccharides by ITC, SPR, and an anticoagulant assay to provide guidelines to engineer nanoparticles for biomedical applications. The interaction between acrylamide nanoparticles (~30 nm) and heparin is mainly enthalpy driven with submicromolar affinity. Hydrogen bonding, ionic interactions, and dehydration of polar groups are identified to be key contributions to the affinity. It has been found that high charge density and cross-linking of the NP can contribute to high affinity. The affinity and binding capacity of heparin can be significantly diminished by an increase in salt concentration while only slightly decreased with an increase of temperature. A striking difference in binding thermodynamics has been observed when the main component of a polymer nanoparticle is changed from acrylamide (enthalpy driven) to N-isopropylacryalmide (entropy driven). This change in thermodynamics leads to different responses of these two types of polymer NPs to salt concentration and temperature. Select synthetic polymer nanoparticles have also been shown to inhibit protein-heparin interactions and thus offer the potential for therapeutic applications.

  9. Influence of Temperature on the Extractibility of Polysaccharides in Barley

    Directory of Open Access Journals (Sweden)

    Rodica Căpriţă

    2011-10-01

    Full Text Available Barley contains substantial amounts of both soluble and insoluble non-starch polysaccharides (NSP. The main watersoluble NSP in barley are highly viscous β-glucans. Monogastric animals, including humans and birds, cannotsynthesize β-glucanase, and the amount of β-glucanase derived from barley grain and bacteria in the gastrointestinaltract is insufficient to completely hydrolyze β-glucans. In the present investigation, we have studied the influence oftemperature and heating time on the extractibility of soluble polysaccharides in barley. Heating the barley samples at60°C and 80°C before extraction has the effect of lowering the soluble fraction of the polysaccharides. The dynamicviscosity values of water extracts from barley decreased up to 21.68% when heating at 60ºC for 15 minutes, and upto 25.30% when heating at 80ºC for 15 minutes, when the determinations were made immediately after extractseparation. Heating the barley samples for 15 minutes at 80°C deactivates the endogenous hydrolytic enzymes.

  10. Recent Advances in Nanocomposite Materials of Graphene Derivatives with Polysaccharides

    Directory of Open Access Journals (Sweden)

    Zoi Terzopoulou

    2015-02-01

    Full Text Available This review article presents the recent advances in syntheses and applications of nanocomposites consisting of graphene derivatives with various polysaccharides. Graphene has recently attracted much interest in the materials field due to its unique 2D structure and outstanding properties. To follow, the physical and mechanical properties of graphene are then introduced. However it was observed that the synthesis of graphene-based nanocomposites had become one of the most important research frontiers in the application of graphene. Therefore, this review also summarizes the recent advances in the synthesis of graphene nanocomposites with polysaccharides, which are abundant in nature and are easily synthesized bio-based polymers. Polysaccharides can be classified in various ways such as cellulose, chitosan, starch, and alginates, each group with unique and different properties. Alginates are considered to be ideal for the preparation of nanocomposites with graphene derivatives due to their environmental-friendly potential. The characteristics of such nanocomposites are discussed here and are compared with regard to their mechanical properties and their various applications.

  11. Extraction and purification of the polysaccharides in Hippohaere rhamnoides L.

    Institute of Scientific and Technical Information of China (English)

    XU Yaqin; JIN Ting; YU Zeyuan; FU Hong

    2007-01-01

    The different extraction technology and purification technology of Hippohpae rhamoides polysaccharides were researched in the paper. The best method of papain extraction were obtained, the ratio of papain 2%, pH at 5.5, temperature at 45℃ and extraction time of 20 min were suitable for papain extraction. The highest content of Hippohpae rhamoides polysaccharides was 44.28 mg·g-1. The optimum process of ultrasonic extraction were obtained, namely extracted for 55 min at 480 W with the material ratio of 1:20. The highest content of Hippohpae rhamoides polysaccharides was 48.63 mg·g-1. The results showed that the ultrasonic and papain extraction together was the best method, the content was 54.30 mg·g-1. After the removing protein, pigment and dialysis. Two fraction were separated from the purified Hippohpae rhamoides by DEAE-cellulose chromatography, the main fraction was collected finally. The fraction was identified by Sepharose CL-4B gel filtration. Ultraviolet spectrometry, freeze-thawing analysis showed that fraction was purified. Its molecular weight was probably 109.4 ku.

  12. Characterization of diferuloylated pectic polysaccharides from quinoa (Chenopodium quinoa WILLD.).

    Science.gov (United States)

    Wefers, Daniel; Gmeiner, Bianca M; Tyl, Catrin E; Bunzel, Mirko

    2015-08-01

    In plants belonging to the order of Caryophyllales, pectic neutral side chains can be substituted with ferulic acid. The ability of ferulic acid to form intra- and/or intermolecular polysaccharide cross-links by dimerization was shown by the isolation and characterization of diferulic acid oligosaccharides from monocotyledonous plants. In this study, two diferulic acid oligosaccharides were isolated from the enzymatic hydrolyzate of seeds of the dicotyledonous pseudocereal quinoa by gel permeation chromatography and preparative HPLC and unambiguously identified by LC-MS(2) and 1D/2D NMR spectroscopy. The isolated oligosaccharides are comprised of 5-5- and 8-O-4-diferulic acid linked to the O2-position of the nonreducing residue of two (1→5)-linked arabinobioses. To get insight into the structure and the degree of phenolic acid substitution of the diferuloylated polysaccharides, polymeric sugar composition, glycosidic linkages, and polysaccharide-bound monomeric phenolic acids and diferulic acids were analyzed. This study demonstrates that diferulic acids are involved into intramolecular and/or intermolecular cross-linking of arabinan chains and may have a major impact on cell wall architecture of quinoa and other dicotyledonous plants of the order of Caryophyllales.

  13. Preparation and Identification of Angelica sinensis Polysaccharide-iron Complex

    Institute of Scientific and Technical Information of China (English)

    WANG Kai-ping; ZHANG Yu; DAI Li-quan

    2005-01-01

    Angelica sinensis polysaccharide(ASP) was extracted from Angelica sinensis by boiling water. An Angelica sinensis polysaccharide-iron complex(APC) was prepared under the alkaline condition by adding a ferric chloride solution to the ASP solution. Then some identifiable properties of the complex were studied. The content of iron (Ⅲ) in the complex was determined with iodometry. The thermal property, the microscopic structure, the spectral characteristics, and N, C, H contents of the complex were examined by a variety of techniques including DSC, TEM, IR,NMR, and elemental analysis. The content of iron (Ⅲ) in the complex ranges from 10% to 40%. The DSC result shows that the melting point of the complex is about 450 ℃. The TEM result shows that the complex has an iron(Ⅲ)core(β-FeOOH core) linked by hydroxy and oxy bridges, with the polysaccharide chains attached to the surface of the core. The IR and NMR results also show that there is aβ-FeOOH core in the complex. The elemental analysis shows that the contents of N, C , H in the complex are, respectively, lower than those of N, C, H in ASP. All our studies indicate that the APC consists of aβ-FeOOH core surrounded by ASP.

  14. Polysaccharide extraction from Sphallerocarpus gracilis roots by response surface methodology.

    Science.gov (United States)

    Ma, Tingting; Sun, Xiangyu; Tian, Chengrui; Luo, Jiyang; Zheng, Cuiping; Zhan, Jicheng

    2016-07-01

    The extraction process of Sphallerocarpus gracilis root polysaccharides (SGRP) was optimized using response surface methodology with two methods [hot-water extraction (HWE) and ultrasonic-assisted extraction (UAE)]. The antioxidant activities of SGRP were determined, and the structural features of the untreated materials (HWE residue and UAE residue) and the extracted polysaccharides were compared by scanning electron microscopy. Results showed that the optimal UAE conditions were extraction temperature of 81°C, extraction time of 1.7h, liquid-solid ratio of 17ml/g, ultrasonic power of 300W and three extraction cycles. The optimal HWE conditions were 93°C extraction temperature, 3.6h extraction time, 21ml/g liquid-solid ratio and three extraction cycles. UAE offered a higher extraction yield with a shorter time, lower temperature and a lower solvent consumption compared with HWE, and the extracted polysaccharides possessed a higher antioxidant capacity. Therefore, UAE could be used as an alternative to conventional HWE for SGRP extraction.

  15. Polysaccharide-coated PCL nanofibers for wound dressing applications.

    Science.gov (United States)

    Croisier, Florence; Atanasova, Ganka; Poumay, Yves; Jérôme, Christine

    2014-12-01

    Polysaccharide-based nanofibers with a multilayered structure are prepared by combining electrospinning (ESP) and layer-by-layer (LBL) deposition techniques. Charged nanofibers are firstly prepared by electrospinning poly(ε-caprolactone) (PCL) with a block-copolymer bearing carboxylic acid functions. After deprotonation of the acid groups, the layer-by-layer deposition of polyelectrolyte polysaccharides, notably chitosan and hyaluronic acid, is used to coat the electrospun fibers. A multilayered structure is achieved by alternating the deposition of the positively charged chitosan with the deposition of a negatively charged polyelectrolyte. The construction of this multilayered structure is followed by Zeta potential measurements, and confirmed by observation of hollow nanofibers resulting from the dissolution of the PCL core in a selective solvent. These novel polysaccharide-coated PCL fiber mats remarkably combine the mechanical resistance typical of the core material (PCL)-particularly in the hydrated state-with the surface properties of chitosan. The control of the nanofiber structure offered by the electrospinning technology, makes the developed process very promising to precisely design biomaterials for tissue engineering. Preliminary cell culture tests corroborate the potential use of such system in wound healing applications.

  16. Extraction of Opuntia dillenii Haw. Polysaccharides and Their Antioxidant Activities.

    Science.gov (United States)

    Li, Heng; Yuan, Qingxia; Zhou, Xianjiao; Zeng, Fuhua; Lu, Xiangyang

    2016-11-24

    Use of natural polysaccharides in medicine and food has wide interest in research. In this study, we extracted and purified some polysaccharides from cactus Opuntia dillenii Haw. (ODP). Some preliminary functions of these products were characterized. Under the optimal purification conditions, the yield of ODP extracted from the 2-4 month-old Opuntia dillenii Haw. (T-ODP) was 30.60% ± 0.40%, higher than that of ODP from the 5-10 month-old materials (O-ODP) (18.97% ± 0.58%). The extracted ODP was purified by DEAE sepharose fast flow anion exchange and Sephacryl S-400 chromatography with four fractions obtained (ODP-Ia, ODP-Ib, ODP-IIa and ODP-IIb). Analysis with UV-vis chromatography indicated that ODP-Ia and ODP-IIa were relatively homogeneous molecules with a molecular weight of 339 kD and 943 kD, respectively. Results of infrared spectroscopy indicated that ODP, ODP-Ia, and ODP-IIa were acidic polysaccharides. Further, the antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radical, hydroxyl radicals, and superoxide radical in vitro demonstrated that the T-ODP exhibited higher antioxidant activity than the O-ODP, and the purified fraction (ODP-Ia) was superior to the ODP. These results will offer a theoretical basis for further research on the structure-function relationship of ODP and the rational utilization of Opuntia dillenii Haw.

  17. Immunomodulatory Activity and Partial Characterisation of Polysaccharides from Momordica charantia

    Directory of Open Access Journals (Sweden)

    Yuan-Yuan Deng

    2014-08-01

    Full Text Available Momordica charantia Linn. is used as an edible and medicinal vegetable in sub-tropical areas. Until now, studies on its composition and related activities have been confined to compounds of low molecular mass, and no data have been reported concerning the plant’s polysaccharides. In this work, a crude polysaccharide of M. charantia (MCP fruit was isolated by hot water extraction and then purified using DEAE-52 cellulose anion-exchange chromatography to produce two main fractions MCP1 and MCP2. The immunomodulatory effects and physicochemical characteristics of these fractions were investigated in vitro and in vivo. The results showed that intragastric administration of 150 or 300 mg·kg−·d−1 of MCP significantly increased the carbolic particle clearance index, serum haemolysin production, spleen index, thymus index and NK cell cytotoxicity to normal control levels in cyclophosphamide (Cy-induced immunosuppressed mice. Both MCP1 and MCP2 effectively stimulated normal and concanavalin A-induced splenic lymphocyte proliferation in vitro at various doses. The average molecular weights of MCP1 and MCP2, which were measured using high-performance gel permeation chromatography, were 8.55 × 104 Da and 4.41 × 105 Da, respectively. Both fractions exhibited characteristic polysaccharide bands in their Fourier transform infrared spectrum. MCP1 is mainly composed of glucose and galactose, and MCP2 is mainly composed of glucose, mannose and galactose. The results indicate that MCP and its fractions have good potential as immunotherapeutic adjuvants.

  18. Recombinant expression of Streptococcus pneumoniae capsular polysaccharides in Escherichia coli.

    Science.gov (United States)

    Kay, Emily J; Yates, Laura E; Terra, Vanessa S; Cuccui, Jon; Wren, Brendan W

    2016-04-01

    Currently, Streptococcus pneumoniae is responsible for over 14 million cases of pneumonia worldwide annually, and over 1 million deaths, the majority of them children. The major determinant for pathogenesis is a polysaccharide capsule that is variable and is used to distinguish strains based on their serotype. The capsule forms the basis of the pneumococcal polysaccharide vaccine (PPV23) that contains purified capsular polysaccharide from 23 serotypes, and the pneumococcal conjugate vaccine (PCV13), containing 13 common serotypes conjugated to CRM197 (mutant diphtheria toxin). Purified capsule from S. pneumoniae is required for pneumococcal conjugate vaccine production, and costs can be prohibitively high, limiting accessibility of the vaccine in low-income countries. In this study, we demonstrate the recombinant expression of the capsule-encoding locus from four different serotypes of S. pneumoniae within Escherichia coli. Furthermore, we attempt to identify the minimum set of genes necessary to reliably and efficiently express these capsules heterologously. These E. coli strains could be used to produce a supply of S. pneumoniae serotype-specific capsules without the need to culture pathogenic bacteria. Additionally, these strains could be applied to synthetic glycobiological applications: recombinant vaccine production using E. coli outer membrane vesicles or coupling to proteins using protein glycan coupling technology.

  19. Tamarind seed polysaccharide: A promising natural excipient for pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Joshny Joseph

    2012-01-01

    Full Text Available The natural polymers always have exceptional properties which make them distinct from the synthetic polymers and tamarind seed polysaccharide (TSP is one such example which shows more valuable properties making it a useful excipient for a wide range of applications. TSP is a natural polysaccharide obtained from the seeds of Tamarindus indica, recently gaining a wide potential in the field of pharmaceutical and cosmetic industries. Its isolation and characterisation involve simple techniques resulting in cost-effective yield in its production. TSP shows uniqueness in its high drug holding capacity, high swelling index and high thermal stability, especially necessary for various novel drug delivery systems. It also plays the role of stabiliser, thickener, binder, release retardant, modifier, suspending agent, viscosity enhancer, emulsifying agent, as a carrier for novel drug delivery systems in oral, buccal, colon, ocular systems, nanofabrication, wound dressing and is also becoming an important part of food, cosmetics, confectionery and bakery. Various studies and experiments have been carried out to prove its multi-functional potentiality, from which it can be concluded that TSP can be a promising natural polysaccharide having enormous applications. This review focuses on the diversity of applications of TSP.

  20. Purification, Characterization and Biological Activity of Polysaccharides from Dendrobium officinale

    Directory of Open Access Journals (Sweden)

    Kaiwei Huang

    2016-05-01

    Full Text Available Polysaccharide (DOPA from the stem of D. officinale, as well as two fractions (DOPA-1 and DOPA-2 of it, were isolated and purified by DEAE cellulose-52 and Sephacryl S-300 chromatography, and their structural characteristics and bioactivities were investigated. The average molecular weights of DOPA-1 and DOPA-2 were 394 kDa and 362 kDa, respectively. They were mainly composed of d-mannose, d-glucose, and had a backbone consisting of 1,4-linked β-d-Manp and 1,4-linked β-d-Glcp with O-acetyl groups. Bioactivity studies indicated that both DOPA and its purified fractions (DOPA-1 and DOPA-2 could activate splenocytes and macrophages. The D. officinale polysaccharides had stimulatory effects on splenocytes, T-lymphocytes and B-lymphocytes, promoting the cell viability and NO production of RAW 264.7 macrophages. Furthermore, DOPA, DOPA-1 and DOPA-2 were found to protect RAW 264.7 macrophages against hydrogen peroxide (H2O2-induced oxidative injury by promoting cell viability, suppressing apoptosis and ameliorating oxidative lesions. These results suggested that D. officinale polysaccharides possessed antioxidant activity and mild immunostimulatory activity.

  1. Extraction of Opuntia dillenii Haw. Polysaccharides and Their Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Heng Li

    2016-11-01

    Full Text Available Use of natural polysaccharides in medicine and food has wide interest in research. In this study, we extracted and purified some polysaccharides from cactus Opuntia dillenii Haw. (ODP. Some preliminary functions of these products were characterized. Under the optimal purification conditions, the yield of ODP extracted from the 2–4 month-old Opuntia dillenii Haw. (T-ODP was 30.60% ± 0.40%, higher than that of ODP from the 5–10 month-old materials (O-ODP (18.97% ± 0.58%. The extracted ODP was purified by DEAE sepharose fast flow anion exchange and Sephacryl S-400 chromatography with four fractions obtained (ODP-Ia, ODP-Ib, ODP-IIa and ODP-IIb. Analysis with UV-vis chromatography indicated that ODP-Ia and ODP-IIa were relatively homogeneous molecules with a molecular weight of 339 kD and 943 kD, respectively. Results of infrared spectroscopy indicated that ODP, ODP-Ia, and ODP-IIa were acidic polysaccharides. Further, the antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radicals, and superoxide radical in vitro demonstrated that the T-ODP exhibited higher antioxidant activity than the O-ODP, and the purified fraction (ODP-Ia was superior to the ODP. These results will offer a theoretical basis for further research on the structure-function relationship of ODP and the rational utilization of Opuntia dillenii Haw.

  2. Sulfation patterns determine cellular internalization of heparin-like polysaccharides.

    Science.gov (United States)

    Raman, Karthik; Mencio, Caitlin; Desai, Umesh R; Kuberan, Balagurunathan

    2013-04-01

    Heparin is a highly sulfated polysaccharide that serves biologically relevant roles as an anticoagulant and anticancer agent. While it is well-known that modification of heparin's sulfation pattern can drastically influence its ability to bind growth factors and other extracellular molecules, very little is known about the cellular uptake of heparin and the role sulfation patterns serve in affecting its internalization. In this study, we chemically synthesized several fluorescently labeled heparins consisting of a variety of sulfation patterns. These polysaccharides were thoroughly characterized using anion exchange chromatography and size exclusion chromatography. Subsequently, we utilized flow cytometry and confocal imaging to show that sulfation patterns differentially affect the amount of heparin uptake in multiple cell types. This study provides the first comprehensive analysis of the effect of sulfation pattern on the cellular internalization of heparin or heparan sulfate like polysaccharides. The results of this study expand current knowledge regarding heparin internalization and provide insights into developing more effective heparin-based drug conjugates for applications in intracellular drug delivery.

  3. Sulfated Seaweed Polysaccharides as Multifunctional Materials in Drug Delivery Applications

    Science.gov (United States)

    Cunha, Ludmylla; Grenha, Ana

    2016-01-01

    In the last decades, the discovery of metabolites from marine resources showing biological activity has increased significantly. Among marine resources, seaweed is a valuable source of structurally diverse bioactive compounds. The cell walls of marine algae are rich in sulfated polysaccharides, including carrageenan in red algae, ulvan in green algae and fucoidan in brown algae. Sulfated polysaccharides have been increasingly studied over the years in the pharmaceutical field, given their potential usefulness in applications such as the design of drug delivery systems. The purpose of this review is to discuss potential applications of these polymers in drug delivery systems, with a focus on carrageenan, ulvan and fucoidan. General information regarding structure, extraction process and physicochemical properties is presented, along with a brief reference to reported biological activities. For each material, specific applications under the scope of drug delivery are described, addressing in privileged manner particulate carriers, as well as hydrogels and beads. A final section approaches the application of sulfated polysaccharides in targeted drug delivery, focusing with particular interest the capacity for macrophage targeting. PMID:26927134

  4. Structure versus anticoagulant and antithrombotic actions of marine sulfated polysaccharides

    Directory of Open Access Journals (Sweden)

    Vitor Hugo Pomin

    2012-08-01

    Full Text Available Marine sulfated polysaccharides (MSP, such as sulfated fucans (SF, sulfated galactans (SG and glycosaminoglycans (GAG isolated from either algae or invertebrate animals, are highly anionic polysaccharides capable of interacting with certain cationic proteins, such as (co-factors of the coagulation cascade during clotting-inhibition processes. These molecular complexes between MSP and coagulation-related proteins might, at first glance, be assumed to be driven mostly by electrostatic interactions. However, a systematic comparison using several novel sulfated polysaccharides composed of repetitive oligosaccharides with clear sulfation patterns has shown that these molecular interactions are regulated essentially by the stereochemistry of the glycans (which depends on a conjunction of anomericity, monosaccharide, conformational preference, and glycosylation and sulfation sites, rather than just a simple consequence of their negative charge density (mainly the number of sulfate groups. Here, we present an overview of the structure-function relationships of MSP, correlating their structures with their potential anticoagulant and antithrombotic actions, since pathologies related to the cardiovascular system are one of the major causes of illness and mortality in the world.

  5. Polysaccharides with immunomodulating properties from the bark of Parkia biglobosa.

    Science.gov (United States)

    Zou, Yuan-Feng; Zhang, Bing-Zhao; Inngjerdingen, Kari Tvete; Barsett, Hilde; Diallo, Drissa; Michaelsen, Terje Einar; El-Zoubair, Elnour; Paulsen, Berit Smestad

    2014-01-30

    The bark of Parkia biglobosa is used in traditional medicine to cure a wide range of illnesses. Polysaccharides were extracted from the bark with 50% ethanol-water, 50°C and 100°C water, and seven active fractions obtained by anion exchange chromatography and gel filtration. The complement fixation and macrophage stimulating activities of the different fractions were determined. The acidic fractions PBEII-I and PBEII-IV were the most active in the complement fixation assay, but the other fractions were also potent compared to the positive control BPII from Biophytum petersianum. Fractions PBEII-I and PBEII-IV were also the most potent fractions in stimulating macrophages to release nitric oxide. Structural studies showed that PBEII-I and PBEII-IV were pectic type polysaccharides, containing arabinogalactan type II structures. The observed differences in biological activities among the seven purified polysaccharide sub-fractions are probably due to differences in monosaccharide compositions, linkage types and molecular sizes.

  6. Treatment Characteristics of Polysaccharides and Endotoxin Using Oxygen Plasma Produced by RF Discharge

    Science.gov (United States)

    Kitazaki, Satoshi; Hayashi, Nobuya; Goto, Masaaki

    2010-10-01

    Treatment of polysaccharides and endotoxin were attempted using oxygen plasma produced by RF discharge. Oxygen radicals observed by optical light emission spectra are factors of decomposition of polysaccharides and endotoxin. Fourier transform infrared spectra indicate that most of chemical bonds in the polysaccharides are dissociated after irradiation of the oxygen plasma. Also, the decomposition rate of endotoxin was approximately 90% after irradiation of the oxygen plasma for 180 min.

  7. Polysaccharide enriched immunomodulatory fractions from Tinospora cordifolia (Willd) miers ax hook. f. & Thoms.

    Science.gov (United States)

    Sharma, Upendra; Bala, Manju; Saini, Rikki; Verma, Praveen Kumar; Kumar, Neeraj; Singh, Bikram; Munshi, Renuka Kulkarni; Bhalerao, Supriya

    2012-09-01

    Tinospora cordifolia is used in Ayurveda as "Rasayanas" to improve the immune system and the body resistance against infections. Polysaccharides are the main constituents which are considered to be responsible for immune enhancement. In this study, immunomodulatory activity of three polysaccharide enriched fractions was evaluated using the polymorphonuclear leukocyte function test. Sugar composition was determined by GC-MS analysis of the derivatised fractions. The active polysaccharide fractions mainly constitute glucose, fructose and arabinose as monomer units.

  8. 微藻多糖的研究进展%Research progress of microalgae polysaccharide

    Institute of Scientific and Technical Information of China (English)

    李洁琼; 刘红全; 袁莎

    2016-01-01

    The structure of microalgae polysaccharide is analyzed.The purification technologies and main biological activities of microalgae polysaccharide are reviewed.Some suggestions about microalgae polysaccharide are also put forward.%针对微藻多糖的结构组成、分离纯化技术和主要生物活性进行概述,并对其研究进展提出展望.

  9. Extraction, Characterization, and Molecular Weight Determination of Senna tora (L.) Seed Polysaccharide

    OpenAIRE

    Pawar, Harshal A.; K. G. Lalitha

    2015-01-01

    The objective of the present work was extraction of polysaccharide from Senna tora L. seed and its characterization as a pharmaceutical excipient. Polysaccharide extraction was based on mechanical separation of the endosperm of seeds of Senna tora, water dissolution, centrifugation, and precipitation with acetone. Standard procedures were used to study the viscosity, micromeritic properties, and microbial bioburden. Accelerated stability study was carried out on isolated polysaccharide for si...

  10. ¿Una película de vaqueros contra indios? Reseña del libro: Velasco Ávila, Cuauhtémoc. 2012. La frontera étnica en el noreste mexicano. Los comanches entre 1800-1841. Historias de desencuentros y destierros. México: Ciesas-Inah. ISBN: 9786074861549

    Directory of Open Access Journals (Sweden)

    Lara Cisneros Gerardo

    2013-12-01

    Full Text Available ¿Quién de niño, o de joven no se emocionó con una película de vaqueros? Al leer y disfrutar las más de 400 páginas de este bello libro no podía evitar recordar múltiples escenas de películas de vaqueros producidas en Hollywood. El conflicto que esto me producía fue ocasión para pasar del asombro a la incomodidad y luego a la reflexión. Y es que sin duda, para hacer esas películas la industria cinematográfica californiana abrevó en la historiografía producida en su país para explicar el devenir de los estados sureños y la épica construcción de su frontera sur.

  11. Fractionation, partial characterization and bioactivity of water-soluble polysaccharides and polysaccharide-protein complexes from Pleurotus geesteranus.

    Science.gov (United States)

    Zhang, Mei; Zhu, Lin; Cui, Steve W; Wang, Qi; Zhou, Ting; Shen, Hengsheng

    2011-01-01

    Fractionation and purification of mushroom polysaccharides is a critical process for mushroom clinical application. After a hot-water treatment, the crude Pleurotus geesteranus (PG) was further fractionated into four fractions (PG-1, -2, -3, -4) using gradient precipitation with water and ammonia sulphate. By controlling the initial polymer concentration and ratio of solvents, this process produced PG fractions with high chemical uniformity and narrow Mw distribution without free proteins. Structurally, PG-1 and PG-2 are pure homopolysaccharide mainly composed of glucose; and PG-3 and PG-4 are heteropolysaccharide-protein complexes. PG-2, a high M(w) fraction mainly composed of glucose presented significant cytotoxicity at the concentration of 200 and 100 μg/ml to human breast cancer cells. Here, we report a new mushroom polysaccharides extraction and fractionation method, with which we produced four fractions of PG with PG-2 appearing effective anti-tumour activity.

  12. [Bacterial polysaccharides of polymyxan 88A. Basic characteristics and extent of possible uses].

    Science.gov (United States)

    Matora, A V; Ignatova, E N; Zhemerichkin, D A; Egorenkova, I V; Shipin, O V; Panasenko, V I; Arsen'eva, L Iu; Barkovskiĭ, A L

    1992-01-01

    A new high-viscous polysaccharide polymyxan from Bacillus polymyxa 88A is described. Polymyxan consists of an acid high-viscous polysaccharide (Mw 1-10 MD) and a neutral low-viscous polysaccharide (Mw 100-300 kD), which is a glucomannan containing equal amounts of monosaccharides and traces of uronic acids. The acid high-viscous polysaccharide consists of 36% glucose, 36% mannose, 7% galactose and 21% glucuronic acid. Data are presented on the application of polymyxan in baking industry and for preparation of drilling muds.

  13. Screening of natural polysaccharides extracted from the fruits of Pithecellobium dulce as a pharmaceutical adjuvant.

    Science.gov (United States)

    S, Preethi; A, Mary Saral

    2016-11-01

    Polysaccharides were extracted from the dried fruiting bodies of Pithecellobium dulce with 20% ethanol by microwave-assisted extraction. The polysaccharides were isolated by ion exchange chromatography and afford three water-soluble polysaccharides PDP-1, PDP-2, and PDP-3. These isolated compounds were subjected to acid hydrolysis, methylation, IR and GC-MS for its compositional analysis and revealed that all the three fractions are heteropolysaccharides. PDP-1 was found to be composed of xylose, mannose, galactose and Rhamnose. PDP-2 and PDP-3 composed of xylose, Rhamnose, glucose, ribose, galactose, and mannose. The micromeretic properties of the extracted polysaccharides possessed a bulk density of 0.69g/ml, 0.65g/ml and 0.71g/ml for PDP-1, PDP-2, and PDP-3 respectively. The Hausner's ratio and Carr's index confirm the good flow property and compressibility of the polysaccharides. The polysaccharides extracted from Pithecellobium dulce fruits were tested for its application as a pharmaceutical adjuvant. The in vitro drug release study suggests that the extracted polysaccharides are potential candidates as a pharmaceutical adjuvant. Furthermore, the three isolated polysaccharides were subjected to its radical scavenging activity using DPPH, phospho molybdenum assay and reducing power assay. The results exhibited that the polysaccharides can be explored as a novel natural antioxidant and can be recommended as a functional food.

  14. Extraction of polysaccharides and the antioxidant activity from the seeds of Plantago asiatica L.

    Science.gov (United States)

    Ye, Chun-Lin; Hu, Wei-Lian; Dai, De-Hui

    2011-11-01

    The extraction conditions of polysaccharides from Plantago asiatica L. seeds were investigated. Four parameters affecting the polysaccharides extraction, extraction times, water to sample, extraction temperature and single extraction time, were determined by orthogonal experiments. Under the optimized conditions, the polysaccharides yield of P. asiatica L. seeds was 2.467%. The antioxidant activities of the polysaccharides were investigated. The reducing power of the polysaccharides was dose dependent, and the reducing capacity of the polysaccharides was inferior to butylated hydroxytoluene, which is known to be a strong reducing agent. The scavenging rates of the polysaccharides on superoxide and 1,1-diphenyl-2-picrylhydrazyl radicals were 79.7% and 81.4%, at polysaccharides concentration of 0.75 mg/mL, respectively, a scavenging rates approximately similar to that of 0.75 mg/mL ascorbic acid (83.5% and 85.1%, respectively). Furthermore, it exhibited a moderate concentration-dependent ABTS radical scavenging activity, ferrous ion chelating potency and H(2)O(2) scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of the polysaccharides extracted from Semen Plantaginis.

  15. Structure of the polysaccharides from the lipopolysaccharide of Azospirillum brasilense Jm125A2.

    Science.gov (United States)

    Sigida, Elena N; Fedonenko, Yuliya P; Shashkov, Alexander S; Zdorovenko, Evelina L; Konnova, Svetlana A; Ignatov, Vladimir V; Knirel, Yuriy A

    2015-10-30

    Two polysaccharides were obtained by mild acid degradation of the lipopolysaccharide of associative nitrogen-fixing bacteria Azospirillum brasilense Jm125A2 isolated from the rhizosphere of a pearl millet. The following structures of the polysaccharides were established by sugar and methylation analyses, Smith degradation, and (1)H and (13)C NMR spectroscopy: [Formula: see text] Structure 1 has been reported earlier for a polysaccharide from A. brasilense S17 (Fedonenko YP, Konnova ON, Zdorovenko EL, Konnova SA, Zatonsky GV, Shaskov AS, Ignatov VV, Knirel YA. Carbohydr Res 2008;343:810-6), whereas to our knowledge structure 2 has not been hitherto found in bacterial polysaccharides.

  16. “uso y evaluación de dos aceites esenciales (canela y clavo de olor) para control de las pudriciones fungosas y determinación de la vida útil mediante películas protectoras comestibles en papaya (carica papaya c.v.hawaiana)”

    OpenAIRE

    Martínez Martínez, Leovina Ingrid

    2013-01-01

    La alta demanda de los consumidores por productos con características naturales y larga vida ha determinado el estudio de nuevas técnicas de preservación y, entre ellas, el estudio de la formulación y desarrollo películas con el fin de ser utilizadas como recubrimiento de alimentos para aumentar su vida útil. Los objetivos del presente trabajo fueron determinar el efecto de la aplicación de una película comestible (almidón de maíz, acido esteárico, glicerol, agua)con diferentes concentracione...

  17. Polysaccharides Purified from Wild Cordyceps Activate FGF2/FGFR1c Signaling

    Institute of Scientific and Technical Information of China (English)

    ZENG Yangyang; HAN Zhangrun; YU Guangli; HAO Jiejie; ZHANG Lijuan

    2015-01-01

    Land animals as well as all organisms in ocean synthesize sulfated polysaccharides. Fungi split from animals about 1.5 billion years ago. As fungi make the evolutionary journey from ocean to land, the biggest changes in their living environment may be a sharp decrease in salt concentration. It is established that sulfated polysaccharides interact with hundreds of signaling molecules and facilitate many signaling transduction pathways, including fibroblast growth factor (FGF) and FGF receptor signaling pathway. The disappearance of sulfated polysaccharides in fungi and plants on land might indicate that polysaccharides without sulfation might be sufficient in facilitating protein ligand/receptor interactions in low salinity land. Recently, it was reported that plants on land start to synthesize sulfated polysaccharides in high salt environment, suggesting that fungi might be able to do the same when ex-posed in such environment. Interestingly, Cordyceps, a fungus habituating inside caterpillar body, is the most valued traditional Chi-nese Medicine. One of the important pharmaceutical active ingredients in Cordyceps is polysaccharides. Therefore, we hypothesize that the salty environment inside caterpillar body might allow the fungi to synthesize sulfated polysaccharides. To test the hypothesis, we isolated polysaccharides from both lava and sporophore of wild Cordyceps and also fromCordyceps militaris cultured without or with added salts. We then measured the polysaccharide activity using a FGF2/FGFR1c signaling-dependent BaF3 cell proliferation assay and found that polysaccharides isolated from wild Cordyceps activated FGF2/FGFR signaling, indicating that the polysaccha-rides synthesized by wild Cordyceps are indeed different from those by the cultured mycelium.

  18. Polysaccharides purified from wild Cordyceps activate FGF2/FGFR1c signaling

    Science.gov (United States)

    Zeng, Yangyang; Han, Zhangrun; Yu, Guangli; Hao, Jiejie; Zhang, Lijuan

    2015-02-01

    Land animals as well as all organisms in ocean synthesize sulfated polysaccharides. Fungi split from animals about 1.5 billion years ago. As fungi make the evolutionary journey from ocean to land, the biggest changes in their living environment may be a sharp decrease in salt concentration. It is established that sulfated polysaccharides interact with hundreds of signaling molecules and facilitate many signaling transduction pathways, including fibroblast growth factor (FGF) and FGF receptor signaling pathway. The disappearance of sulfated polysaccharides in fungi and plants on land might indicate that polysaccharides without sulfation might be sufficient in facilitating protein ligand/receptor interactions in low salinity land. Recently, it was reported that plants on land start to synthesize sulfated polysaccharides in high salt environment, suggesting that fungi might be able to do the same when exposed in such environment. Interestingly, Cordyceps, a fungus habituating inside caterpillar body, is the most valued traditional Chinese Medicine. One of the important pharmaceutical active ingredients in Cordyceps is polysaccharides. Therefore, we hypothesize that the salty environment inside caterpillar body might allow the fungi to synthesize sulfated polysaccharides. To test the hypothesis, we isolated polysaccharides from both lava and sporophore of wild Cordyceps and also from Cordyceps militaris cultured without or with added salts. We then measured the polysaccharide activity using a FGF2/FGFR1c signaling-dependent BaF3 cell proliferation assay and found that polysaccharides isolated from wild Cordyceps activated FGF2/FGFR signaling, indicating that the polysaccharides synthesized by wild Cordyceps are indeed different from those by the cultured mycelium.

  19. Structure of Plant Cell Walls : XVIII. An Analysis of the Extracellular Polysaccharides of Suspension-Cultured Sycamore Cells.

    Science.gov (United States)

    Stevenson, T T; McNeil, M; Darvill, A G; Albersheim, P

    1986-04-01

    The water-soluble polysaccharides (SEPS) secreted into the medium by suspension-cultured sycamore cells were examined to determine whether the polysaccharides were the same as those present in the walls of sycamore cells. The SEPS were made more amenable to fractionation by treatment with a highly purified alpha-1,4-endopolygalacturonase (EPG). The EPG-treated SEPS were fractionated by anion-exchange and gelpermeation chromatography. The following polysaccharides were found: xyloglucan, arabinoxylan, at least two arabinogalactans, a rhamnogalacturonan-II-like polysaccharide, and a polygalacturonic acid-rich polysaccharide. The oligogalacturonide fragments expected from EPG-digested homogalacturonan were also identified. Evidence was obtained for the presence of a rhamnogalacturonan-I-like polysaccharide. All of the above polysaccharides have been isolated from or are believed to be present in sycamore cell walls. Furthermore, all of the noncellulosic polysaccharides known to be present in sycamore cell-walls appear to be present in the SEPS.

  20. Streptococcal Receptor Polysaccharides: Recognition Molecules for Oral Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Kolenbrander Paul E

    2006-06-01

    Full Text Available Abstract Background Strains of viridans group streptococci that initiate colonization of the human tooth surface typically coaggregate with each other and with Actinomyces naeslundii, another member of the developing biofilm community. These interactions generally involve adhesin-mediated recognition of streptococcal receptor polysaccharides (RPS. The objective of our studies is to understand the role of these polysaccharides in oral biofilm development. Methods Different structural types of RPS have been characterized by their reactions with specific antibodies and lectin-like adhesins. Streptococcal gene clusters for RPS biosynthesis were identified, sequenced, characterized and compared. RPS-producing bacteria were detected in biofilm samples using specific antibodies and gene probes. Results Six different types of RPS have been identified from representative viridans group streptococci that coaggregate with A. naeslundii. Each type is composed of a different hexa- or heptasaccharide repeating unit, the structures of which contain host-like motifs, either GalNAcβ1-3Gal or Galβ1-3GalNAc. These motifs account for RPS-mediated recognition, whereas other features of these polysaccharides are more closely associated with RPS antigenicity. The RPS-dependent interaction of S. oralis with A. naeslundii promotes growth of these bacteria and biofilm formation in flowing saliva. Type specific differences in RPS production have been noted among the resident streptococcal floras of different individuals, raising the possibility of RPS-based differences in the composition of oral biofilm communities. Conclusion The structural, functional and molecular properties of streptococcal RPS support a recognition role of these cell surface molecules in oral biofilm formation.

  1. Polysaccharide-based aerogel microspheres for oral drug delivery.

    Science.gov (United States)

    García-González, C A; Jin, M; Gerth, J; Alvarez-Lorenzo, C; Smirnova, I

    2015-03-06

    Polysaccharide-based aerogels in the form of microspheres were investigated as carriers of poorly water soluble drugs for oral administration. These bio-based carriers may combine the biocompatibility of polysaccharides and the enhanced drug loading capacity of dry aerogels. Aerogel microspheres from starch, pectin and alginate were loaded with ketoprofen (anti-inflammatory drug) and benzoic acid (used in the management of urea cycle disorders) via supercritical CO2-assisted adsorption. Amount of drug loaded depended on the aerogel matrix structure and composition and reached values up to 1.0×10(-3) and 1.7×10(-3) g/m(2) for ketoprofen and benzoic acid in starch microspheres. After impregnation, drugs were in the amorphous state in the aerogel microspheres. Release behavior was evaluated in different pH media (pH 1.2 and 6.8). Controlled drug release from pectin and alginate aerogel microspheres fitted Gallagher-Corrigan release model (R(2)>0.99 in both cases), with different relative contribution of erosion and diffusion mechanisms depending on the matrix composition. Release from starch aerogel microspheres was driven by dissolution, fitting the first-order kinetics due to the rigid starch aerogel structure, and showed different release rate constant (k1) depending on the drug (0.075 and 0.160 min(-1) for ketoprofen and benzoic acid, respectively). Overall, the results point out the possibilities of tuning drug loading and release by carefully choosing the polysaccharide used to prepare the aerogels.

  2. Polysaccharide enhances Radix Saposhnikoviae efficacy through inhibiting chromones decomposition in intestinal tract

    Science.gov (United States)

    Yang, Jing-Ming; Jiang, Hua; Dai, Hong-Liang; Wang, Zi-Wei; Jia, Gui-Zhi; Meng, Xiang-Cai

    2016-01-01

    Vegetative but not reproductive stage of Saposhnikovia divaricate (Turxz.) schischk possesses pharmacological activities. However, our recent study showed that reproductive S. divaricate supplemented with polysaccharide showed evidently elevated pharmacological activities and increased cimifugin content in rat serum. The aims of present study were to assess the influence of polysaccharides on the chromones pharmacological activities in Radix Saposhnikoviae (RS), the dried root of vegetative stage of S. divaricate, and to explore the underlying mechanisms. Only cimifugin was detected in the plasma of chromone treated animals and RS polysaccharide significantly increased the plasma content of cimifugin. It was shown that neither cimifugin absorption nor glycoside components transformation in simulated digestive fluid was affected by RS polysaccharide. However, a significant promotion of transformation of cimifugin to more stable prime-O-glucosylcimifugin (PGCN) by RS polysaccharide, and a protective effect of polysaccharide on chromone components were observed in small intestine solutions. Meanwhile, RS polysaccharide produced a significant elevation of cimifugin and PGCN concentration in vivo. Based on these findings, we concluded that RS polysaccharide could greatly increase the content of cimifugin, which might be related to its degradation-proof effect on cimifugin, via transforming cimifugin to comparatively more stable PGCN and spatial structure protection. PMID:27595868

  3. Targeted and non-targeted effects in cell wall polysaccharides from transgenetically modified potato tubers

    NARCIS (Netherlands)

    Huang, J.H.

    2016-01-01

    The plant cell wall is a chemically complex network composed mainly of polysaccharides. Cell wall polysaccharides surround and protect plant cells and are responsible for the stability and rigidity of plant tissue. Pectin is a major component of primary cell wall and the middle lamella of plants. Ho

  4. Non-cellulosic polysaccharides from cotton fibre are differently impacted by textile processing.

    Science.gov (United States)

    Runavot, Jean-Luc; Guo, Xiaoyuan; Willats, William G T; Knox, J Paul; Goubet, Florence; Meulewaeter, Frank

    2014-01-01

    Cotton fibre is mainly composed of cellulose, although non-cellulosic polysaccharides play key roles during fibre development and are still present in the harvested fibre. This study aimed at determining the fate of non-cellulosic polysaccharides during cotton textile processing. We analyzed non-cellulosic cotton fibre polysaccharides during different steps of cotton textile processing using GC-MS, HPLC and comprehensive microarray polymer profiling to obtain monosaccharide and polysaccharide amounts and linkage compositions. Additionally, in situ detection was used to obtain information on polysaccharide localization and accessibility. We show that pectic and hemicellulosic polysaccharide levels decrease during cotton textile processing and that some processing steps have more impact than others. Pectins and arabinose-containing polysaccharides are strongly impacted by the chemical treatments, with most being removed during bleaching and scouring. However, some forms of pectin are more resistant than others. Xylan and xyloglucan are affected in later processing steps and to a lesser extent, whereas callose showed a strong resistance to the chemical processing steps. This study shows that non-cellulosic polysaccharides are differently impacted by the treatments used in cotton textile processing with some hemicelluloses and callose being resistant to these harsh treatments.

  5. Physical Properties Giving the Sensory Perception of Whey Proteins/Polysaccharide Gels

    NARCIS (Netherlands)

    Berg, van den L.; Vliet, van T.; Linden, van der E.; Boekel, van M.A.J.S.; Velde, van de F.

    2008-01-01

    Establishing relationships between physical and sensorial properties of semi-solid foods is essential to develop tailored products. Whey protein/polysaccharide mixed gels were used to model both natural and fabricated semi-solid foods. The presence of various polysaccharides modulated the microstruc

  6. Characterisation of antioxidant and antiproliferative acidic polysaccharides from Chinese wolfberry fruits

    NARCIS (Netherlands)

    He, N.W.; Yang, X.B.; Jiao, Y.D.; Tian, L.; Zhao, Y.

    2012-01-01

    Wolfberry fruit polysaccharides (WFPs) were isolated by hot-water extraction and ethanol precipitation. With HPLC analysis, WFPs were for the first time identified as acidic polysaccharides with galacturonic acid being the main component monosaccharide (24.9%), followed by galactose (21.3%), arabino

  7. A nuclear magnetic resonance approach to the comparison of mucoadhesive properties of polysaccharides for ophthalmic uses.

    Science.gov (United States)

    Uccello-Barretta, Gloria; Nazzi, Samuele; Balzano, Federica; Sansò, Marco

    2011-03-15

    Mucoadhesive properties of tamarind seed polysaccharide (TSP) and larch arabinogalactan (AG), which are developed for ophthalmic applications, were investigated by NMR spectroscopy. Polysaccharide to mucin affinities were compared by using ketotifen fumarate as low molecular weight interaction probe. Proton selective relaxation rate measurements revealed enhanced affinity of TSP to mucin with respect to AG.

  8. High performance flocculating agents based on cationic polysaccharides in relation to coal fine suspension

    Energy Technology Data Exchange (ETDEWEB)

    Pal, S.; Sen, G.; Karmakar, N.C.; Mal, D.; Singh, R.P. [Birla Institute of Technology, Ranchi (India). Dept. of Applied Chemistry

    2008-11-04

    Five polysaccharides namely amylopectin, amylose, glycogen, guar gum and starch have been cationized by grafting with N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride and studied for their flocculation behaviors. Of them, cationic glycogen (Cat Gly) is found to be the best for flocculation of coal suspended sample amongst cationic polysaccharides. Cat Gly was compared with some of the commercial flocculants.

  9. Isolation and structure elucidation of pectic polysaccharide from rose hip fruits (Rosa canina L.)

    NARCIS (Netherlands)

    Ognyanov, Manol; Remoroza, Connie; Schols, Henk A.; Georgiev, Yordan; Kratchanova, Maria; Kratchanov, Christo

    2016-01-01

    A pectic polysaccharide from rose hip (RH) fruits has been obtained by extraction with 1% aqueous citric acid. It was found that the polysaccharide fraction mainly consisted of galacturonic acid (45.5%) next to galactose (5.5%) and arabinose (4.7%). RH pectin is having a relatively high degree of

  10. [Gravity resistance, another graviresponse in plants--function of anti-gravitational polysaccharides].

    Science.gov (United States)

    Hoson, Takayuki; Wakabayashi, Kazuyuki; Soga, Kouichi

    2003-08-01

    The involvement of anti-gravitational polysaccharides in gravity resistance, one of two major gravity responses in plants, was discussed. In dicotyledons, xyloglucans are the only cell wall polysaccharides, whose level, molecular size, and metabolic turnover were modified under both hypergravity and microgravity conditions, suggesting that xyloglucans act as anti-gravitational polysaccharides. In monocotyledonous Poaceae, (1-->3),(1-->4)-beta glucans, instead of xyloglucans, were shown to play a role as anti-gravitational polysaccharides. These polysaccharides are also involved in plant responses to other environmental factors, such as light and temperature, and to some phytohormones, such as auxin and ethylene. Thus, the type of anti-gravitational polysaccharides is different between dicotyledons and Poaceae, but such polysaccharides are universally involved in plant responses to environmental and hormonal signals. In gravity resistance, the gravity signal may be received by the plasma membrane mechanoreceptors, transformed and transduced within each cell, and then may modify the processes of synthesis and secretion of the anti-gravitational polysaccharides and the cell wall enzymes responsible for their degradation, as well as the apoplastic pH, leading to the cell wall reinforcement. A series of events inducing gravity resistance are quite independent of those leading to gravitropism.

  11. Antioxidative activities and chemical characterization of polysaccharides extracted from the basidiomycete Schizophyllum commune

    NARCIS (Netherlands)

    Klaus, A.; Kozarski, M.; Niksic, M.; Jakovljevic, D.; Todorovic, N.; Griensven, van L.J.L.D.

    2011-01-01

    Antioxidant properties of hot water extract (HWE), hot water extracted polysaccharides (HWP) and hot alkali extracted polysaccharides (HWAE) were obtained from fruiting bodies of the wild basidiomycete Schizophyllum commune. All extracts contained both a- and ß-glucans as determined by Megazyme ß-gl

  12. Method to conjugate polysaccharide antigens to surfaces for the detection of antibodies

    DEFF Research Database (Denmark)

    Boas, Ulrik; Lind, Peter; Riber, Ulla

    2014-01-01

    A new generic method for the conjugation of lipopolysaccharide (LPS)-derived polysaccharide antigens from gram-negative bacteria has been developed using Salmonella as a model. After removal of lipid A from the LPS by mild acidolysis, the polysaccharide antigen was conjugated to polystyrene micro...

  13. Structural characterization and biomedical properties of sulfated polysaccharide from the gladius of Sepioteuthis lessoniana (Lesson, 1831).

    Science.gov (United States)

    Seedevi, Palaniappan; Moovendhan, Meivelu; Vairamani, Shanmugam; Shanmugam, Annian

    2016-04-01

    Sulfated polysaccharide was extracted from the internal shell (gladius) of Sepioteuthis lessoniana. The sulfated polysaccharide contained 61.3% of carbohydrate, 0.8% of protein, 28.2% of ash and 1.33% of moisture respectively. The elemental composition was analyzed using CHNS/O analyzer. The molecular weight of sulfated polysaccharide determined through PAGE was found to be as 66 kDa. Monosaccharides analysis revealed that sulfated polysaccharide was composed of rhamnose, galactose, xylose and glucose. The structural features of sulfated polysaccharide were analyzed by FT-IR and NMR spectroscopy. Further the sulfated polysaccharide was evaluated for its antibacterial activity against selected human clinical pathogens, namely Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, Vibrio cholerae, Klebsiella oxytoca, Escherichia coli, Salmonella paratyphi, Proteus mirabilis, Vibrio parahaemolyticus and Streptococcus pyogenes using agar well diffusion method. The polysaccharide has showed good antibacterial activity and MIC and MBC have also been evaluated. The anticancer activity was tested against HeLa cell line by MTT assay. The Cytotoxic Concentration (CC50) was observed as 700 μg/ml and the maximum anticancer activity of 62.89% was recorded at 200 μg/ml; whereas, the lowest of 9.87% was observed at 25 μg/ml. In conclusion, the sulfated polysaccharide is an alternate, non-toxic and cheap source of substance that showed good antibacterial and anticancer acitivity.

  14. Extraction, purification, characterization and antioxidant activities of polysaccharides from Cistanche tubulosa.

    Science.gov (United States)

    Zhang, Wiejie; Huang, Jing; Wang, Wei; Li, Qian; Chen, Yao; Feng, Weiwei; Zheng, Daheng; Zhao, Ting; Mao, Guanghua; Yang, Liuqing; Wu, Xiangyang

    2016-12-01

    An efficient ultrasonic-cellulase-assisted extraction (UCE) of Cistanche tubulosa polysaccharide (CTP) was established. The response surface methodology based on Box-Behnken Design was employed to further optimize extraction conditions. After quaternary ammonium salt precipitation, the polysaccharide of C. tubulosa was characterized by different techniques. The results showed that a maximum polysaccharide yield of 22.31±0.45% was achieved at a pH of 5.2 for 31.5min at 54.1°C. Compared to hot water extraction, the yield of CTP in UCE and polysaccharide content increased to 44.96% and 70.13±2.19%, respectively. There was no marked difference among polysaccharides extracted using different methods from the infrared spectrum. Ultrasonic-cellulase-assisted extraction polysaccharide showed a fibrous structure from scanning electron microscopy and was composed of rhamnose, mannose, glucose, and galactose in a molar ratio of 2.18:1:28.29:1.43 by gas chromatography. The circular dichroism results indicated that polysaccharides had a maximum positive peak around 210nm with different peak values. The thermogravimetric analysis and differential scanning calorimetry were used to test the thermostability of CTP. Besides, CTP demonstrated appreciable antioxidant potential on antioxidant experiments in vitro. The results suggested that UCE is an effective method for CTP extraction and its polysaccharide showed appreciable antioxidant activity.

  15. Characterization and antioxidant activities of degraded polysaccharides from Poria cocos sclerotium.

    Science.gov (United States)

    Tang, Jin; Nie, Jing; Li, Danping; Zhu, Wenjun; Zhang, Shaopeng; Ma, Fang; Sun, Qiao; Song, Jia; Zheng, Yonglian; Chen, Ping

    2014-05-25

    Poria cocos F.A.Wolf is a Chinese traditional medicine used to treat chronic gastritis, edema, nephrosis, gastric atony, and acute gastroenteric catarrh. Polysaccharides are the main active component of P. cocos. We obtained polysaccharides PCP-1, PCP-2, and PCP-3 from the degradation of P. cocos polysaccharides (PCP) with different concentrations of H2O2 solution. Molecular weights were determined by high performance size exclusion chromatography. HPLC analysis of monosaccharide composition confirmed that PCP-1, PCP-2, and PCP-3 are heteropolysaccharides composed of glucose and arabinose. IR spectra indicated obvious characteristic peaks of polysaccharides. The antioxidant activities of these polysaccharides were evaluated by established in vitro systems, including scavenging activity of hydroxyl radicals, ABTS radicals, and ferrous ions. The degradation polysaccharides exhibited obvious and concentration-dependent antioxidant properties. In addition, DNA binding analysis showed that PCP-1 had a stronger capacity than other polysaccharides to interact with DNA. However, each polysaccharide had a certain capacity for DNA damage protection.

  16. Synthesis, characterization and evaluation of thiolated tamarind seed polysaccharide as a mucoadhesive polymer.

    Science.gov (United States)

    Kaur, Harmanmeet; Yadav, Shikha; Ahuja, Munish; Dilbaghi, Neeraj

    2012-11-06

    In the present study, thiol-functionalization of tamarind seed polysaccharide was carried out by esterification with thioglycolic acid. Thiol-functionalization was confirmed by SH stretch in Fourier-transformed infra-red spectra at 2586 cm(-1). It was found to possess 104.5 mM of thiol groups per gram. The results of differential scanning calorimetry and X-ray diffraction study indicate increase in crystallinity. Polymer compacts of thiolated tamarind seed polysaccharide required 6.85-fold greater force to detach from the mucin coated membrane than that of tamarind seed polysaccharide. Comparative evaluation of Carbopol-based metronidazole gels containing thiolated tamarind seed polysaccharide with gels containing tamarind seed polysaccharide for mucoadhesive strength using chicken ileum by modified balance method revealed higher mucoadhesion of gels containing thiolated tamarind seed polysaccharide. Further, the gels containing tamarind seed polysaccharide and thiolated tamarind seed polysaccharide released the drug by Fickian-diffusion following the first-order and Higuchi's-square root release kinetics, respectively.

  17. Blend-modification of soy protein/lauric acid edible films using polysaccharides.

    Science.gov (United States)

    Pan, Hongyang; Jiang, Bo; Chen, Jie; Jin, Zhengyu

    2014-05-15

    Different types of polysaccharides (propyleneglycol alginate (PGA), pectin, carrageenan and aloe polysaccharide) were incorporated into soy protein isolate (SPI)/lauric acid (La) films using a co-drying process or by direct addition to form biodegradable composite films with modified water vapour permeability (WVP) and mechanical properties. The WVP of SPI/La/polysaccharide films decreased when polysaccharides were added using the co-drying process, regardless of the type of polysaccharide. The tensile strength of SPI/La film was increased by the addition of polysaccharides, and the percentage elongation at break was increased by incorporating PGA using the co-drying process. Regarding oxygen-barrier performance, no notable differences were observed between the SPI/La and SPI/La/polysaccharide films. The most significant improvement was observed by blending PGA, with the co-dried preparation exhibiting better properties than the direct-addition preparation. Scanning electron microscopy (SEM) revealed that the microstructures of the films are the basis for the differences in the barrier and mechanical properties of the modified blends of SPI, polysaccharides and La.

  18. Effect of atracylodes rhizome polysaccharide in rats with adenine-induced chronic renal failure.

    Science.gov (United States)

    Yang, C; Liu, C; Zhou, Q; Xie, Y C; Qiu, X M; Feng, X

    2015-01-01

    The aim of the study was to elucidate the therapeutic effects of Atracylodes rhizome polysaccharide on adenine-induced chronic renal failure in rats. Fifty male Sprague Dawley rats were selected and randomly divided in to 5 groups (n=10 rats per group): The normal control group, the chronic renal failure pathological control group, the dexamethasone treatment group and two Atracylodes rhizome polysaccharide treatment groups, treated with two different concentrations of the polysaccharide, the Atracylodes rhizome polysaccharide high group and the Atracylodes rhizome polysaccharide low group. All the rats, except those in the normal control group were fed adenine-enriched diets, containing 10 g adenine per kg food for 3 weeks. After being fed with adenine, the dexamethasone treatment group, Atracylodes rhizome polysaccharide high group and Atracylodes rhizome polysaccharide low group rats were administered the drug orally for 2 weeks. On day 35, the kidney coefficient of the rats and the serum levels of creatinine, blood urea nitrogen, total protein and hemalbumin were determined. Subsequent to experimentation on a model of chronic renal failure in rats, the preparation was proven to be able to reduce serum levels of creatinine, blood urea nitrogen and hemalbumin levels (Prenal function. Atracylodes rhizome polysaccharide had reversed the majority of the indices of chronic renal failure in rats.

  19. Sulfated polysaccharides and cell differentiation in the sea urchin embryo.

    Science.gov (United States)

    Løvtrup-Rein, H; Løvtrup, S

    1984-01-01

    The synthesis of sulfated polysaccharides during the embryonic development of Paracentrotus lividus has been investigated by incorporation of radioactive sulfate, glucose, glucosamine and fucose. The following substances become labelled: fucan sulfate (approximately 60%), heparan sulfate (approximately 20%) and dermatan sulfate (approximately 20%), and possibly a very slight amount of chondroitin sulfate. In animalized and vegetalized embryos, the rate of incorporation is significantly reduced, and furthermore dermatan sulfate is almost absent in animalized embryos. It is concluded that this substance is associated with the differentiation of vegetative cells, possibly the mesenchyme cells.

  20. Immunomodulatory activity of polysaccharides isolated from Alchornea cordifolia

    Science.gov (United States)

    Kouakou, Koffi; Schepetkin, Igor A.; Yapi, Ahoua; Kirpotina, Liliya N.; Jutila, Mark A.; Quinn, Mark T.

    2013-01-01

    Ethnopharmacological relevance Extracts of leaves from different species of the genus Alchornea have been used for centuries to treat a variety of medicinal problems in tropical Africa. However, little is known about the high-molecular weight active components conferring therapeutic properties to these extracts. Objective The aim of this study was to evaluate the immunomodulatory activity of polysaccharides isolated from the leaves of Alchornea cordifolia. Materials and methods Water-soluble polysaccharides from leaves of A. cordifolia were extracted and fractionated by DEAE-cellulose, Diaion HP-20, and size-exclusion chromatography. Molecular weight, sugar analysis, and other physical and chemical characterization of the fractions were performed. Immunomodulatory activity of the polysaccharide fractions was evaluated by determining their ability to induce monocyte/macrophage nitric oxide (NO) and cytokine production. Activation of mitogen activated protein kinases (MAPK) was also assessed using a phospho-MAPK array. Activation of nuclear factor κB (NF-κB) was measured using an alkaline phosphatase reporter gene assay in THP1-Blue monocytic cells. Results Six polysaccharide fractions from A. cordifolia were isolated. Fractions containing type II arabinogalactan had potent immunomodulatory activity. Particularly, the parent fraction AP-AU and its high-molecular weight sub-fraction AP-AU1 (average Mr was estimated to be 39.5 kDa) induced production of NO and cytokines [interleukin (IL)-1β, -6, -10, tumor necrosis factor (TNF)-α, and granulocyte macrophage-colony stimulating factor (GM-CSF)] in human peripheral blood mononuclear cells and human and murine monocyte/macrophages cell lines in vitro. Furthermore, treatment with AP-AU1 induced phosphorylation of Akt2, p38δ/p38γ, p70S6K1, RSK2, and mTOR, as well as stimulation of NF-κB transcriptional activity. Conclusion Our results provide a molecular basis to explain a portion of the beneficial therapeutic

  1. Protective effect of Rhodiola rosea polysaccharides on cryopreserved boar sperm.

    Science.gov (United States)

    Yang, Shen-Min; Wang, Ting; Wen, Duan-Gai; Hou, Jian-Quan; Li, Hai-Bo

    2016-01-01

    Cryopreservation brings sublethal damage to sperm, resulting in reduced fertile life of sperm. Rhodiola rosea polysaccharides (RPs) have antiviral, antioxidant and antitumor activities. In the present study, the cryoprotective effect of RPs on boar sperm quality parameters after frozen-thawed process was investigated. Boar sperm was cryopreserved in the extender with RPs added at concentrations of 0 (used as control), 2, 4, 6, 8 and 10mg/L and their effects on the quality of frozen-thawed boar sperm were assessed. Addition of RPs significantly improved sperm motility, mitochondrial activity, acrosomal integrity, plasma membrane integrity, superoxide dismutase and glutathione peroxidase activity and decreased sperm malonaldehyde level (pboar sperm.

  2. [Mutagen properties of water-soluble polysaccharides from Acorus calamus].

    Science.gov (United States)

    Gur'ev, A M; Belousov, M B; Akhmedzhanov, R R; Iusubov, M S; Voronova, O L; Karpova, G V; Churin, A A

    2010-08-01

    Mutagenic properties of water soluble polysaccharides (WSPS) extracted from Acorus calamus L. have been studied. Neither a single intravenous injection nor a course intraperitoneal introduction of WSPS in a dose of 1/2 LD50 to mice of the CBA/CaLac line increases the level of cytogenetic disorders in the bone marrow cells. The investigation of WSPS by means of the somatic mosaicism test showed that the given dose of WSPS does not increase the rate of mutant spots on Drosophila wings.

  3. Immunologically active polysaccharides of Arnica montana cell cultures.

    Science.gov (United States)

    Puhlmann, J; Zenk, M H; Wagner, H

    1991-01-01

    From the nutrition medium of Arnica montana cell cultures two homogeneous polysaccharides, an acidic arabino-3,6-galactan-protein with mean Mr of 100,000 and a neutral fucogalactoxyloglucan with mean Mr of 22,500 have been isolated by DEAE-Sepharose CL-6B and Sephacryl S-400 column chromatography. Their structures were elucidated mainly by methylation analysis, partial acidic and enzymatic hydrolysis and 13C NMR spectroscopy. The fucogalactoxyloglucan shows a pronounced enhancement of phagocytosis in vivo. The arabino-3,6-galactan-protein displays a strong anticomplementary effect and stimulates macrophages to excrete the tumour necrosis factor (TNF alpha).

  4. Chemical Characteristic of Bioactive Polysaccharides Isolated from Ornithogalum caudatum Ait.

    Institute of Scientific and Technical Information of China (English)

    SHI Lei; LI Juan; LIU Wen-Xiang; WANG Yong; LIU Zhi-qiang; LIU Shu-ying

    2003-01-01

    A water-soluble crude extract prepared from Ornithogalum caudatum Ait.(OCA) showing a high immunomodulating activitiy was isolated and characterized by virtue of gel filtration and column chromatography. The presence of the monosaccharides has been established by the chemical analysis. The quantitative analysis of the alditol acetate derivatives of them showed the ratios of the monosaccharides analyzed by means of GC respectively. The concentrations of protein(280 nm) and carbohydrate(496 nm) were detected respectively. The information of the molecular weight from the pure polysaccharide was obtained by several standard Dextrans from the Sephadex chromatography.

  5. Estudio del anión no,-en la formación de películas delgadas de PbS por baño químico.

    OpenAIRE

    LUNA HERNÁNDEZ, E.; PEÑA MÉNDEZ, Y.; LUGO LOREDO, S.

    2011-01-01

    En el presente trabajo se obtuvieron pcHcu1as delgadas de PbS sobre sustratos de vidrio por el método de depósito por baño químico, partiendo de Pb(NO3), ó Pb(CH3 COO)2. Las películas obtenidas fueron tratadas térmicamente a 200 y 300 oC durante 1 h en N2. A través de difracción de rayos X se confirmó la formación del PbS (JCPDS 077-0244). La brecha de energia evaluada fue de 0.8 a 0.9 eV y suconductividad alrededor de 0.14 a 0.94

  6. Estudio de las propiedades eléctricas de películas de óxido de silicio crecidas térmicamente en ambiente de óxido nitroso

    OpenAIRE

    Adán Luna Flores; Jesús Carrillo López; Arturo Morales Acevedo

    2003-01-01

    En este trabajo se presenta un estudio de las propiedades dieléctricas de óxido de silicio nitridado (SiO2:N) y en la interfaz silicio / SiO2:N. Las capas dieléctricas de SiO2:N se depositaron térmicamente en un ambiente de óxido nitroso (N2O), variando la presión y temperatura en un rango de 1 a 3 atm y de 1000 a 1150 °C, respectivamente. También se hace una comparación entre las películas de SiO2:N y SiO2 depositado térmicamente en un ambiente de oxígeno seco a 1000 °C y 1 atm de presión. L...

  7. Drácula: La sangre como el amor nunca muere. Análisis hermenéutico de la sangre en la película de Francis Ford Coppola

    OpenAIRE

    Osorio Osorio, Jhon Jaime; Blu Radio

    2015-01-01

    Hablar de Drácula es hablar de sangre. La literatura de vampiros establece esta asociación casi indivisible en la que el líquido vital de los humanos es fundamental para la inmortalidad de estos míticos seres. El análisis que aquí se presenta es el resultado de varias miradas a la película y de diferentes asociaciones establecidas entre los elementos más reiterativos en la cinta. Se partió de visualización del trabajo cinematográfico, luego se realizó la lectura de la imagen y del sonido, y f...

  8. Características sensoriais e microbiológicas de maçãs minimamente processadas recobertas com películas Sensorial and microbiological characteristics of freshly cut apples with edible coating

    Directory of Open Access Journals (Sweden)

    Luciana Cristina Brigatto Fontes

    2007-03-01

    Full Text Available O objetivo do trabalho foi avaliar as características sensoriais e a microbiologia durante armazenamento refrigerado de maçãs da cultivar Royal Gala minimamente processada (MP, tratadas com solução conservadora e películas comestíveis (dextrina, amido de mandioca e alginato de sódio. Maçãs MP tratadas apenas com a solução conservadora destacaram-se por apresentarem características mais próximas de uma maçã natural recém cortada nos parâmetros de aparência, odor e textura. Nos parâmetros de sabor, este tratamento mostrou-se diferenciado da maçã natural em virtude dos ácidos e sais presentes na solução. As maçãs MP com películas de dextrina e fécula de mandioca apresentaram notas semelhantes nos parâmetros avaliados, evidenciando maior umidade e menor escurecimento que o controle. A película de alginato apresentou-se visivelmente mais espessa e com brilho, o que os provadores associaram como sendo de aparência artificial. Quanto ao tempo de armazenamento, as alterações significativas da maioria dos parâmetros sensoriais avaliados manifestaram-se no 5º dia de armazenamento para as maçãs MP do tratamento controle e, principalmente no 9° dia de armazenamento, para os produtos com película. Foi detectada ausência de Salmonella nas maçãs utilizadas no processamento. Não foram detectados coliformes totais e fecais nas maçãs MP durante todo o período de armazenamento estudado.The aim of this work was to evaluate the sensorial and microbiological characteristics during the refrigerated storage of Royal Gala fresh cut (FC apples treated with conservative solution and edible coating (dextrin, cassava starch and sodium alginate. Freshly cut apples treated with a conservative solution are only really close to the natural ones for presenting characteristics similar in parameters of appearance, odor and texture. In the flavor parameters, this treatment revealed a different flavor to the natural one due to acids and

  9. Estructura de la imagen en las películas de cine animado. Up: Una Aventura de Altura, Coraline y la Puerta Secreta, ToyStory 3, Frankenweenie y Hotel Transylvania

    OpenAIRE

    Valencia Giraldo, Mariana; López Ríos, Ximena

    2015-01-01

    Esta investigación buscó ampliar, de manera descriptiva, la construcción de las imágenes en el cine animado, en los últimos siete años, a través de las diferentes técnicas de animación que facilitan la creación de diversos espacios y tiempos visuales. Devela cómo el montaje, en cinco películas, puede transformar el significado de símbolos en cada uno de los veinticinco momentos de análisis (escenas). Para ello se trabajó con cuatro categorías empíricas: estructuras de la imagen, imagen en mov...

  10. Characterization of Bacterial Polysaccharide Capsules and Detection in the Presence of Deliquescent Water by Atomic Force Microscopy

    OpenAIRE

    Su, Hai-Nan; Chen, Zhi-Hua; Liu, Sheng-Bo; Qiao, Li-Ping; Chen, Xiu-Lan; He, Hai-Lun; Zhao, Xian; Zhou, Bai-Cheng; Zhang, Yu-Zhong

    2012-01-01

    We detected polysaccharide capsules from Zunongwangia profunda SM-A87 with atomic force microscopy (AFM). The molecular organization of the capsules at the single-polysaccharide-chain level was reported. Furthermore, we found that with ScanAsyst mode the polysaccharide capsules could be detected even in the presence of deliquescent water covering the capsule.

  11. The cyclic-di-GMP signaling pathway in the Lyme disease spirochete, Borrelia burgdorferi

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Novak

    2014-05-01

    Full Text Available In nature, the Lyme disease spirochete Borrelia burgdorferi cycles between the unrelated environments of the Ixodes tick vector and mammalian host. In order to survive transmission between hosts, B. burgdorferi must be able to not only detect changes in its environment, but also rapidly and appropriately respond to these changes. One manner in which this obligate parasite regulates and adapts to its changing environment is through cyclic-di-GMP (c-di-GMP signaling. c-di-GMP has been shown to be instrumental in orchestrating the adaptation of B. burgdorferi to the tick environment. B. burgdorferi possesses only one set of c-di-GMP-metabolizing genes (one diguanylate cyclase and two distinct phosphodiesterases and one c-di-GMP-binding PilZ-domain protein designated as PlzA. While studies in the realm of c-di-GMP signaling in B. burgdorferi have exploded in the last few years, there are still many more questions than answers. Elucidation of the importance of c-di-GMP signaling to B. burgdorferi may lead to the identification of mechanisms that are critical for the survival of B. burgdorferi in the tick phase of the enzootic cycle as well as potentially delineate a role (if any c-di-GMP may play in the transmission and virulence of B. burgdorferi during the enzootic cycle, thereby enabling the development of effective drugs for the prevention and/or treatment of Lyme disease.

  12. Crystal structure of the YajQ-family protein XC_3703 from Xanthomonas campestris pv. campestris.

    Science.gov (United States)

    Zhao, Zhixin; Wu, Zhen; Zhang, Jun

    2016-09-01

    As an important bacterial second messenger, bis-(3',5')-cyclic diguanylate (cyclic di-GMP or c-di-GMP) has been implicated in numerous biological activities, including biofilm formation, motility, survival and virulence. These processes are manipulated by the binding of c-di-GMP to its receptors. XC_3703 from the plant pathogen Xanthomonas campestris pv. campestris, which belongs to the YajQ family of proteins, has recently been identified as a potential c-di-GMP receptor. XC_3703, together with XC_2801, functions as a transcription factor activating virulence-related genes, which can be reversed by the binding of c-di-GMP to XC_3703. However, the structural basis of how c-di-GMP regulates XC_3703 remains elusive. In this study, the structure of XC_3703 was determined to 2.1 Å resolution using the molecular-replacement method. The structure of XC_3703 consists of two domains adopting the same topology, which is similar to that of the RNA-recognition motif (RRM). Arg65, which is conserved among the c-di-GMP-binding subfamily of the YajQ family of proteins, together with Phe80 in domain II, forms a putative c-di-GMP binding site.

  13. Screening of polysaccharides from tamarind, fenugreek and jackfruit seeds as pharmaceutical excipients.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Santra, Kousik

    2015-08-01

    The paper describes the isolation and screening of plant polysaccharides namely tamarind seed polysaccharide (TSP), fenugreek seed mucilage (FSM) and jackfruit seed starch (JFSS) from tamarind (Tamarindus indica L.) seeds, fenugreek (Trigonella foenum-graecum L.) seeds and jackfruit (Artocarpus heterophyllus L.) seeds, respectively. The yields of isolated dried TSP, FSM and JFSS were 47.00%, 17.36% and 18.86%, respectively. Various physicochemical properties like colour, odour, taste, solubility in water, pH and viscosity of these isolated plant polysaccharides were assessed. Isolated polysaccharide samples were subjected to some phytochemical identification tests. FTIR and (1)H NMR analyses of isolated polysaccharides were performed, which suggest the presence of sugar residues. Isolated TSP, FSM and JFSS can be used as pharmaceutical excipients in various pharmaceutical formulations.

  14. [Study on totai flavonoids of Epimedium assisted with soybean polysaccharide spray-drying powder].

    Science.gov (United States)

    Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Deng, Jia-hui

    2015-08-01

    In order to evaluate the characteristics of the spray drying of total flavonoids of Epimedium extracts assisted with soybean polysaccharide, a certain percentage of soybean polysaccharide or polyvidone were added to the total flavonoids of Epimedium extract to conduct the spray drying. The effect of soybean polysaccharides against the wall sticking effect of the spray drying was detected, as well as the powder property of total flavonoids of Epimedium spray drying powder and the dissolution in vitro behavior of the effective component. Compared with the total flavonoids of Epimedium spray drying powder, soybean polysaccharide revealed a significant anti-wall sticking effect. The spray drying power which had no notable change in the grain size made a increase in the fluidity, improvement in the moisture absorption and remarkable rise in the dissolution in vitro behavior. It was worth further studying the application of soybean polysaccharide in spray drying power of traditional Chinese medicine.

  15. Antiviral Potential of Algae Polysaccharides Isolated from Marine Sources: A Review

    Directory of Open Access Journals (Sweden)

    Azin Ahmadi

    2015-01-01

    Full Text Available From food to fertilizer, algal derived products are largely employed in assorted industries, including agricultural, biomedical, food, and pharmaceutical industries. Among different chemical compositions isolated from algae, polysaccharides are the most well-established compounds, which were subjected to a variety of studies due to extensive bioactivities. Over the past few decades, the promising results for antiviral potential of algae-derived polysaccharides have advocated them as inordinate candidates for pharmaceutical research. Numerous studies have isolated various algal polysaccharides possessing antiviral activities, including carrageenan, alginate, fucan, laminaran, and naviculan. In addition, different mechanisms of action have been reported for these polysaccharides, such as inhibiting the binding or internalization of virus into the host cells or suppressing DNA replication and protein synthesis. This review strives for compiling previous antiviral studies of algae-derived polysaccharides and their mechanism of action towards their development as natural antiviral agents for future investigations.

  16. Lycium barbarum polysaccharides promotes in vivo proliferation of adult rat retinal progenitor cells

    Directory of Open Access Journals (Sweden)

    Hua Wang

    2015-01-01

    Full Text Available Lycium barbarum is a widely used Chinese herbal medicine prescription for protection of optic nerve. However, it remains unclear regarding the effects of Lycium barbarum polysaccharides, the main component of Lycium barbarum, on in vivo proliferation of adult ciliary body cells. In this study, adult rats were intragastrically administered low- and high-dose Lycium barbarum polysaccharides (1 and 10 mg/kg for 35 days and those intragastrically administered phosphate buffered saline served as controls. The number of Ki-67-positive cells in rat ciliary body in the Lycium barbarum polysaccharides groups, in particular low-dose Lycium barbarum polysaccharides group, was significantly greater than that in the phosphate buffered saline group. Ki-67-positive rat ciliary body cells expressed nestin but they did not express glial fibrillary acidic protein. These findings suggest that Lycium barbarum polysaccharides can promote the proliferation of adult rat retinal progenitor cells and the proliferated cells present with neuronal phenotype.

  17. Fingerprint analysis of polysaccharides from different Ganoderma by HPLC combined with chemometrics methods.

    Science.gov (United States)

    Sun, Xiaomei; Wang, Haohao; Han, Xiaofeng; Chen, Shangwei; Zhu, Song; Dai, Jun

    2014-12-19

    A fingerprint analysis method has been developed for characterization and discrimination of polysaccharides from different Ganoderma by high performance liquid chromatography (HPLC) coupled with chemometrics means. The polysaccharides were extracted under ultrasonic-assisted condition, and then partly hydrolyzed with trifluoroacetic acid. Monosaccharides and oligosaccharides in the hydrolyzates were subjected to pre-column derivatization with 1-phenyl-3-methyl-5-pyrazolone and HPLC analysis, which will generate unique fingerprint information related to chemical composition and structure of polysaccharides. The peak data were imported to professional software in order to obtain standard fingerprint profiles and evaluate similarity of different samples. Meanwhile, the data were further processed by hierarchical cluster analysis and principal component analysis. Polysaccharides from different parts or species of Ganoderma or polysaccharides from the same parts of Ganoderma but from different geographical regions or different strains could be differentiated clearly. This fingerprint analysis method can be applied to identification and quality control of different Ganoderma and their products.

  18. Chemical features of Ganoderma polysaccharides with antioxidant, antitumor and antimicrobial activities.

    Science.gov (United States)

    Ferreira, Isabel C F R; Heleno, Sandrina A; Reis, Filipa S; Stojkovic, Dejan; Queiroz, Maria João R P; Vasconcelos, M Helena; Sokovic, Marina

    2015-06-01

    Ganoderma genus comprises one of the most commonly studied species worldwide, Ganoderma lucidum. However, other Ganoderma species have been also reported as important sources of bioactive compounds. Polysaccharides are important contributors to the medicinal properties reported for Ganoderma species, as demonstrated by the numerous publications, including reviews, on this matter. Yet, what are the chemical features of Ganoderma polysaccharides that have bioactivity? In the present manuscript, the chemical features of Ganoderma polysaccharides with reported antioxidant, antitumor and antimicrobial activities (the most studied worldwide) are analyzed in detail. The composition of sugars (homo- versus hetero-glucans and other polysaccharides), type of glycosidic linkages, branching patterns, and linkage to proteins are discussed. Methods for extraction, isolation and identification are evaluated and, finally, the bioactivity of polysaccharidic extracts and purified compounds are discussed. The integration of data allows deduction of structure-activity relationships and gives clues to the chemical aspects involved in Ganoderma bioactivity.

  19. Biocatalytic cross-linking of pectic polysaccharides for designed food functionality

    DEFF Research Database (Denmark)

    Zaidel, Dayang Norulfairuz Abang; Meyer, Anne S.

    2012-01-01

    Recent research has demonstrated how cross-linking of pectic polysaccharides to obtain gel formation can be promoted by enzymatic catalysis reactions, and provide opportunities for functional upgrading of pectic polysaccharides present in agro-industrial sidestreams. This review highlights the me...... specific enzymatic reactions, and highlights the most recent data concerning enzyme catalyzed engineering of cross-links for in situ structural design of functional properties of foods.......Recent research has demonstrated how cross-linking of pectic polysaccharides to obtain gel formation can be promoted by enzymatic catalysis reactions, and provide opportunities for functional upgrading of pectic polysaccharides present in agro-industrial sidestreams. This review highlights...... the mechanisms of formation of functional pectic polysaccharide cross-links, including covalent cross-links (notably phenolic esters and uronyl ester linkages) and non-covalent, ionic cross-links (which involve calcium and borate ester links). The treatise examines how such cross-links can be designed via...

  20. Studies on the Antiviral Activities in vitro of Polysaccharide from Eucheuma striatum

    Institute of Scientific and Technical Information of China (English)

    CEN,Ying-Zhou; KHOO,Gaik-Ming; YE,Shao-Ming; RUI,Wen

    2004-01-01

    @@ To assay the antiviral activities on HSV-1 and CVB3 in vitro of the polysaccharide from Eucheuma striatum, its antiviral mechanism was explored. Vero cells were infected by HSV-1 and CVB3, and they were cultured with serial dilutions of polysaccharide. The cells cytotoxicity of Polysaccharide was evaluated by the MTT method. The inhibitory effects were evaluated by the cytopathic effect (CPE). Its antiviral mechanism was researched by the method of giving samples in different time. The polysaccharide could inhibit the CPE of cells infected by HSV-1 and CVB3. It showed low cytotoxicity on vero cells. Its antiviral activities were better than those of acyclovir and ribavirin which were run in parallel as the positive control samples. The polysaccharide from Eucheuma striatum has potent antiviral activities. Its antiviral mechanism is that it can prevent the virus from absorbing to the cell surface.