The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Gordon D. Brown - One of the best experts on this subject based on the ideXlab platform.
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dectin 1 plays a redundant role in the immunomodulatory activities of β glucan rich ligands in vivo
Microbes and Infection, 2013Co-Authors: Mohlopheni J Marakalala, Gordon D. Brown, David L Williams, Mihai G Netea, Jennifer C Hoving, Rolf E EngstadAbstract:β-Glucans are known for their ability to trigger both protective and damaging immune responses. Here we have explored the role of the Beta-Glucan receptor Dectin-1 in archetypical models of protective and non-protective immunomodulation induced by Beta-Glucan rich ligands. In the first model, we explored the role of Dectin-1 in the ability of soluble purified β-glucans to mediate protection against systemic Staphylococcus aureus infection in mice. In the second model, we explored the role of Dectin-1 in zymosan induced multiple organ dysfunction syndrome. In both cases, these β-glucan rich compounds had marked effects in vivo which were unaltered by Dectin-1 deficiency, suggesting that this receptor has a redundant role in these murine models.
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β glucans and dectin 1
Annals of the New York Academy of Sciences, 2008Co-Authors: Vicky S Tsoni, Gordon D. BrownAbstract:Beta-Glucans are naturally occurring carbohydrates that possess immune-modulating activities, but their mechanisms of action are largely unknown. Recent discoveries, however, including identification of Beta-Glucan receptors, such as dectin-1, have started to shed some light on the mechanisms underlying the properties of these carbohydrates. The characterization of dectin-1, in particular, has revealed some of the processes involved in Beta-Glucan sensing, intracellular signaling, and induction of cellular responses and has provided new insights into the role of Beta-Glucans in immunity and disease. Here we review both Beta-Glucans and their receptor, dectin-1.
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soluble dectin 1 as a tool to detect β glucans
Journal of Immunological Methods, 2006Co-Authors: Lisa M Graham, David L Williams, Siamon Gordon, Vicky S Tsoni, Janet A Willment, Philip R Taylor, Kevin M Dennehy, Gordon D. BrownAbstract:Beta-Glucans are structural components of fungal cell walls which are involved in the immune recognition of fungal pathogens and possess beneficial immunomodulatory activities in isolated form. Here we have developed a soluble chimeric form of the major mammalian Beta-Glucan receptor, Dectin-1, and demonstrate its application for the detection and characterisation of soluble and insoluble Beta-Glucans, including fungal particles, using ELISA, flow cytometric and fluorescence-based microscopy assays.
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ligands for the β glucan receptor dectin 1 assigned using designer microarrays of oligosaccharide probes neoglycolipids generated from glucan polysaccharides
Journal of Biological Chemistry, 2006Co-Authors: Angelina S Palma, Siamon Gordon, Ten Feizi, Yibing Zhang, Mark S Stoll, Alexander M Lawson, Esther Diazrodriguez, Maria A Campanerorhodes, Julia Costa, Gordon D. BrownAbstract:Dectin-1 is a C-type lectin-like receptor on leukocytes that mediates phagocytosis and inflammatory mediator production in innate immunity to fungal pathogens. Dectin-1 lacks residues involved in calcium ligation that mediates carbohydrate-binding by classical C-type lectins; nevertheless, it binds zymosan, a particulate Beta-Glucan-rich extract of Saccharomyces cerevisiae, and binding is inhibited by polysaccharides rich in beta1,3- or both beta1,3- and beta1,6-linked glucose. The oligosaccharide ligands on glucans recognized by Dectin-1 have not yet been delineated precisely. It is also not known whether Dectin-1 can interact with other types of carbohydrates. We have investigated this, since Dectin-1 shows glucan-independent binding to a subset of T-lymphocytes and is involved in triggering their proliferation. Here we assign oligosaccharide ligands for Dectin-1 using the neoglycolipid-based oligosaccharide microarray technology, a unique approach for constructing microarrays of lipid-linked oligosaccharide probes from desired sources. We generate "designer" microarrays from three glucan polysaccharides, a neutral soluble glucan isolated from S. cerevisiae and two bacterial glucans, curdlan from Alcaligenes faecalis and pustulan from Umbilicaria papullosa, and use these in conjunction with 187 diverse, sequence-defined, predominantly mammalian-type, oligosaccharide probes. Among these, Dectin-1 binding is detected exclusively to 1,3-linked glucose oligomers, the minimum length required for detectable binding being a 10- or 11-mer. Thus, the ligands assigned so far are exogenous rather than endogenous. We further show that Dectin-1 ligands, 11-13 gluco-oligomers, in clustered form (displayed on liposomes), mimic the macromolecular Beta-Glucans and compete with zymosan binding and triggering of tumor necrosis factor-alpha secretion by a Dectin-1-expressing macrophage cell line.
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the beta glucan receptor dectin 1 recognizes specific morphologies of aspergillus fumigatus
PLOS Pathogens, 2005Co-Authors: Chad Steele, David L Williams, Siamon Gordon, Rekha R Rapaka, Allison E Metz, Shannon M Pop, Jay K Kolls, Gordon D. BrownAbstract:Alveolar macrophages represent a first-line innate host defense mechanism for clearing inhaled Aspergillus fumigatus from the lungs, yet contradictory data exist as to which alveolar macrophage recognition receptor is critical for innate immunity to A. fumigatus. Acknowledging that the A. fumigatus cell wall contains a high beta-1,3–glucan content, we questioned whether the Beta-Glucan receptor dectin-1 played a role in this recognition process. Monoclonal antibody, soluble receptor, and competitive carbohydrate blockage indicated that the alveolar macrophage inflammatory response, specifically the production of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, CXCL2/macrophage inflammatory protein-2 (MIP-2), CCL3/macrophage inflammatory protein-1α (MIP-1α), granulocyte-colony stimulating factor (G-CSF), and granulocyte monocyte–CSF (GM-CSF), to live A. fumigatus was dependent on recognition via the Beta-Glucan receptor dectin-1. The inflammatory response was triggered at the highest level by A. fumigatus swollen conidia and early germlings and correlated to the levels of surface-exposed beta glucans, indicating that dectin-1 preferentially recognizes specific morphological forms of A. fumigatus. Intratracheal administration of A. fumigatus conidia to mice in the presence of a soluble dectin-Fc fusion protein reduced both lung proinflammatory cytokine/chemokine levels and cellular recruitment while modestly increasing the A. fumigatus fungal burden, illustrating the importance of Beta-Glucan–initiated dectin-1 signaling in defense against this pathogen. Collectively, these data show that dectin-1 is centrally required for the generation of alveolar macrophage proinflammatory responses to A. fumigatus and to our knowledge provides the first in vivo evidence for the role of dectin-1 in fungal innate defense.
David L Williams - One of the best experts on this subject based on the ideXlab platform.
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dectin 1 plays a redundant role in the immunomodulatory activities of β glucan rich ligands in vivo
Microbes and Infection, 2013Co-Authors: Mohlopheni J Marakalala, Gordon D. Brown, David L Williams, Mihai G Netea, Jennifer C Hoving, Rolf E EngstadAbstract:β-Glucans are known for their ability to trigger both protective and damaging immune responses. Here we have explored the role of the Beta-Glucan receptor Dectin-1 in archetypical models of protective and non-protective immunomodulation induced by Beta-Glucan rich ligands. In the first model, we explored the role of Dectin-1 in the ability of soluble purified β-glucans to mediate protection against systemic Staphylococcus aureus infection in mice. In the second model, we explored the role of Dectin-1 in zymosan induced multiple organ dysfunction syndrome. In both cases, these β-glucan rich compounds had marked effects in vivo which were unaltered by Dectin-1 deficiency, suggesting that this receptor has a redundant role in these murine models.
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soluble dectin 1 as a tool to detect β glucans
Journal of Immunological Methods, 2006Co-Authors: Lisa M Graham, David L Williams, Siamon Gordon, Vicky S Tsoni, Janet A Willment, Philip R Taylor, Kevin M Dennehy, Gordon D. BrownAbstract:Beta-Glucans are structural components of fungal cell walls which are involved in the immune recognition of fungal pathogens and possess beneficial immunomodulatory activities in isolated form. Here we have developed a soluble chimeric form of the major mammalian Beta-Glucan receptor, Dectin-1, and demonstrate its application for the detection and characterisation of soluble and insoluble Beta-Glucans, including fungal particles, using ELISA, flow cytometric and fluorescence-based microscopy assays.
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the beta glucan receptor dectin 1 recognizes specific morphologies of aspergillus fumigatus
PLOS Pathogens, 2005Co-Authors: Chad Steele, David L Williams, Siamon Gordon, Rekha R Rapaka, Allison E Metz, Shannon M Pop, Jay K Kolls, Gordon D. BrownAbstract:Alveolar macrophages represent a first-line innate host defense mechanism for clearing inhaled Aspergillus fumigatus from the lungs, yet contradictory data exist as to which alveolar macrophage recognition receptor is critical for innate immunity to A. fumigatus. Acknowledging that the A. fumigatus cell wall contains a high beta-1,3–glucan content, we questioned whether the Beta-Glucan receptor dectin-1 played a role in this recognition process. Monoclonal antibody, soluble receptor, and competitive carbohydrate blockage indicated that the alveolar macrophage inflammatory response, specifically the production of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, CXCL2/macrophage inflammatory protein-2 (MIP-2), CCL3/macrophage inflammatory protein-1α (MIP-1α), granulocyte-colony stimulating factor (G-CSF), and granulocyte monocyte–CSF (GM-CSF), to live A. fumigatus was dependent on recognition via the Beta-Glucan receptor dectin-1. The inflammatory response was triggered at the highest level by A. fumigatus swollen conidia and early germlings and correlated to the levels of surface-exposed beta glucans, indicating that dectin-1 preferentially recognizes specific morphological forms of A. fumigatus. Intratracheal administration of A. fumigatus conidia to mice in the presence of a soluble dectin-Fc fusion protein reduced both lung proinflammatory cytokine/chemokine levels and cellular recruitment while modestly increasing the A. fumigatus fungal burden, illustrating the importance of Beta-Glucan–initiated dectin-1 signaling in defense against this pathogen. Collectively, these data show that dectin-1 is centrally required for the generation of alveolar macrophage proinflammatory responses to A. fumigatus and to our knowledge provides the first in vivo evidence for the role of dectin-1 in fungal innate defense.
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the role of signr1 and the beta glucan receptor dectin 1 in the nonopsonic recognition of yeast by specific macrophages
Journal of Immunology, 2004Co-Authors: Philip R Taylor, Gordon D. Brown, David L Williams, Janet A Willment, Jurgen Herre, Siamon GordonAbstract:We recently demonstrated that the Beta-Glucan receptor Dectin-1 (betaGR) was the major nonopsonic Beta-Glucan receptor on macrophages (Mphi) for the yeast-derived particle zymosan. However, on resident peritoneal Mphi, we identified an additional mannan-inhibitable receptor for zymosan that was distinct from the Mphi mannose receptor (MR). In this study, we have studied the mannose-binding potential of murine Mphi and identified the dendritic cell-specific ICAM-3-grabbing nonintegrin homolog, SIGN-related 1 (SIGNR1), as a major MR on murine resident peritoneal Mphi. Both SIGNR1 and betaGR cooperated in the nonopsonic recognition of zymosan by these Mphi. When SIGNR1 was introduced into NIH3T3 fibroblasts or RAW 264.7 Mphi, it conferred marked zymosan-binding potential on these cells. However, in the nonprofessional phagocytes (NIH3T3), SIGNR1 was found to be poorly phagocytic, suggesting that other receptors such as betaGR may play a more dominant role in particle internalization on professional phagocytes. Binding of zymosan to RAW 264.7 Mphi expressing SIGNR1 resulted in TNF-alpha production. Treatment of RAW 264.7 Mphi expressing SIGNR1, which express low levels of betaGR, with Beta-Glucans had little effect on binding or TNF-alpha production, indicating that there was no absolute requirement for betaGR in this process. These studies have identified SIGNR1 as a major MR for fungal and other pathogens present on specific subsets of Mphi.
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glucans exhibit weak antioxidant activity but stimulate macrophage free radical activity
Free Radical Biology and Medicine, 2001Co-Authors: Ekaterini Tsiapali, John Kalbfleisch, Harry E Ensley, Sarah Whaley, William I Browder, David L WilliamsAbstract:Polymeric carbohydrates have been reported to modulate inflammatory responses in vitro and in vivo. Previous reports suggest that certain carbohydrate polymers, such as (1-->3)-beta-D-glucans, may possess free radical scavenging activity. If glucans are free radical scavengers then it might explain, in part, the ability of these ligands to modulate inflammatory responses. The present study examined the free radical scavenging activity of a variety of carbohydrate polymers and the effect of the polymers on free radical levels in a murine macrophage cell line. All of the carbohydrates exhibited concentration dependent antioxidant effects (EC(50) range = 807 to 43 microg/ml). However, the antioxidant activity for the carbohydrates was modest in comparison with PDTC (EC(50) = 0.13 microg/ml) and the carbohydrate concentration required for antioxidant activity was high (x EC(50) = 283 microg/ml). The antioxidant ability of the polymers was greater (p < .05) than their monosaccharide constituents, i.e., dextrose EC(50) = 807 vs. glucan sulfate EC(50) = 43 microg/ml. Coincubation of glucans with murine J774a.1 cells increased free radical levels when compared to controls. Therefore, the weak free radical scavenging activity of glucan polymers cannot explain their modulatory effect on inflammatory responses in tissue culture and/or disease models of inflammation.
Siamon Gordon - One of the best experts on this subject based on the ideXlab platform.
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differential high affinity interaction of dectin 1 with natural or synthetic glucans is dependent upon primary structure and is influenced by polymer chain length and side chain branching
Journal of Pharmacology and Experimental Therapeutics, 2008Co-Authors: Elizabeth L Adams, Peter J Rice, Harry E Ensley, Bridget M Graves, Siamon Gordon, Mario A Monteiro, Erzsebet Pappszabo, Douglas W Lowman, Trevor D PowerAbstract:Glucans are structurally diverse fungal biopolymers that stimulate innate immunity and are fungal pathogen-associated molecular patterns. Dectin-1 is a C-type lectin-like pattern recognition receptor that binds glucans and induces innate immune responses to fungal pathogens. We examined the effect of glucan structure on recognition and binding by murine recombinant Dectin-1 with a library of natural product and synthetic (1-->3)-beta/(1-->6)-Beta-Glucans as well as nonglucan polymers. Dectin-1 is highly specific for glucans with a pure (1-->3)-beta-linked backbone structure. Although Dectin-1 is highly specific for (1-->3)-beta-d-glucans, it does not recognize all glucans equally. Dectin-1 differentially interacted with (1-->3)-beta-d-glucans over a very wide range of binding affinities (2.6 mM-2.2 pM). One of the most striking observations that emerged from this study was the remarkable high-affinity interaction of Dectin-1 with certain glucans (2.2 pM). These data also demonstrated that synthetic glucan ligands interact with Dectin-1 and that binding affinity increased in synthetic glucans containing a single glucose side-chain branch. We also observed differential recognition of glucans derived from saprophytes and pathogens. We found that glucan derived from a saprophytic yeast was recognized with higher affinity than glucan derived from the pathogen Candida albicans. Structural analysis demonstrated that glucan backbone chain length and (1-->6)-beta side-chain branching strongly influenced Dectin-1 binding affinity. These data demonstrate: 1) the specificity of Dectin-1 for glucans; 2) that Dectin-1 differentiates between glucan ligands based on structural determinants; and 3) that Dectin-1 can recognize and interact with both natural product and synthetic glucan ligands.
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soluble dectin 1 as a tool to detect β glucans
Journal of Immunological Methods, 2006Co-Authors: Lisa M Graham, David L Williams, Siamon Gordon, Vicky S Tsoni, Janet A Willment, Philip R Taylor, Kevin M Dennehy, Gordon D. BrownAbstract:Beta-Glucans are structural components of fungal cell walls which are involved in the immune recognition of fungal pathogens and possess beneficial immunomodulatory activities in isolated form. Here we have developed a soluble chimeric form of the major mammalian Beta-Glucan receptor, Dectin-1, and demonstrate its application for the detection and characterisation of soluble and insoluble Beta-Glucans, including fungal particles, using ELISA, flow cytometric and fluorescence-based microscopy assays.
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ligands for the β glucan receptor dectin 1 assigned using designer microarrays of oligosaccharide probes neoglycolipids generated from glucan polysaccharides
Journal of Biological Chemistry, 2006Co-Authors: Angelina S Palma, Siamon Gordon, Ten Feizi, Yibing Zhang, Mark S Stoll, Alexander M Lawson, Esther Diazrodriguez, Maria A Campanerorhodes, Julia Costa, Gordon D. BrownAbstract:Dectin-1 is a C-type lectin-like receptor on leukocytes that mediates phagocytosis and inflammatory mediator production in innate immunity to fungal pathogens. Dectin-1 lacks residues involved in calcium ligation that mediates carbohydrate-binding by classical C-type lectins; nevertheless, it binds zymosan, a particulate Beta-Glucan-rich extract of Saccharomyces cerevisiae, and binding is inhibited by polysaccharides rich in beta1,3- or both beta1,3- and beta1,6-linked glucose. The oligosaccharide ligands on glucans recognized by Dectin-1 have not yet been delineated precisely. It is also not known whether Dectin-1 can interact with other types of carbohydrates. We have investigated this, since Dectin-1 shows glucan-independent binding to a subset of T-lymphocytes and is involved in triggering their proliferation. Here we assign oligosaccharide ligands for Dectin-1 using the neoglycolipid-based oligosaccharide microarray technology, a unique approach for constructing microarrays of lipid-linked oligosaccharide probes from desired sources. We generate "designer" microarrays from three glucan polysaccharides, a neutral soluble glucan isolated from S. cerevisiae and two bacterial glucans, curdlan from Alcaligenes faecalis and pustulan from Umbilicaria papullosa, and use these in conjunction with 187 diverse, sequence-defined, predominantly mammalian-type, oligosaccharide probes. Among these, Dectin-1 binding is detected exclusively to 1,3-linked glucose oligomers, the minimum length required for detectable binding being a 10- or 11-mer. Thus, the ligands assigned so far are exogenous rather than endogenous. We further show that Dectin-1 ligands, 11-13 gluco-oligomers, in clustered form (displayed on liposomes), mimic the macromolecular Beta-Glucans and compete with zymosan binding and triggering of tumor necrosis factor-alpha secretion by a Dectin-1-expressing macrophage cell line.
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the beta glucan receptor dectin 1 recognizes specific morphologies of aspergillus fumigatus
PLOS Pathogens, 2005Co-Authors: Chad Steele, David L Williams, Siamon Gordon, Rekha R Rapaka, Allison E Metz, Shannon M Pop, Jay K Kolls, Gordon D. BrownAbstract:Alveolar macrophages represent a first-line innate host defense mechanism for clearing inhaled Aspergillus fumigatus from the lungs, yet contradictory data exist as to which alveolar macrophage recognition receptor is critical for innate immunity to A. fumigatus. Acknowledging that the A. fumigatus cell wall contains a high beta-1,3–glucan content, we questioned whether the Beta-Glucan receptor dectin-1 played a role in this recognition process. Monoclonal antibody, soluble receptor, and competitive carbohydrate blockage indicated that the alveolar macrophage inflammatory response, specifically the production of tumor necrosis factor-α (TNF-α), interleukin-1α (IL-1α), IL-1β, IL-6, CXCL2/macrophage inflammatory protein-2 (MIP-2), CCL3/macrophage inflammatory protein-1α (MIP-1α), granulocyte-colony stimulating factor (G-CSF), and granulocyte monocyte–CSF (GM-CSF), to live A. fumigatus was dependent on recognition via the Beta-Glucan receptor dectin-1. The inflammatory response was triggered at the highest level by A. fumigatus swollen conidia and early germlings and correlated to the levels of surface-exposed beta glucans, indicating that dectin-1 preferentially recognizes specific morphological forms of A. fumigatus. Intratracheal administration of A. fumigatus conidia to mice in the presence of a soluble dectin-Fc fusion protein reduced both lung proinflammatory cytokine/chemokine levels and cellular recruitment while modestly increasing the A. fumigatus fungal burden, illustrating the importance of Beta-Glucan–initiated dectin-1 signaling in defense against this pathogen. Collectively, these data show that dectin-1 is centrally required for the generation of alveolar macrophage proinflammatory responses to A. fumigatus and to our knowledge provides the first in vivo evidence for the role of dectin-1 in fungal innate defense.
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the role of signr1 and the beta glucan receptor dectin 1 in the nonopsonic recognition of yeast by specific macrophages
Journal of Immunology, 2004Co-Authors: Philip R Taylor, Gordon D. Brown, David L Williams, Janet A Willment, Jurgen Herre, Siamon GordonAbstract:We recently demonstrated that the Beta-Glucan receptor Dectin-1 (betaGR) was the major nonopsonic Beta-Glucan receptor on macrophages (Mphi) for the yeast-derived particle zymosan. However, on resident peritoneal Mphi, we identified an additional mannan-inhibitable receptor for zymosan that was distinct from the Mphi mannose receptor (MR). In this study, we have studied the mannose-binding potential of murine Mphi and identified the dendritic cell-specific ICAM-3-grabbing nonintegrin homolog, SIGN-related 1 (SIGNR1), as a major MR on murine resident peritoneal Mphi. Both SIGNR1 and betaGR cooperated in the nonopsonic recognition of zymosan by these Mphi. When SIGNR1 was introduced into NIH3T3 fibroblasts or RAW 264.7 Mphi, it conferred marked zymosan-binding potential on these cells. However, in the nonprofessional phagocytes (NIH3T3), SIGNR1 was found to be poorly phagocytic, suggesting that other receptors such as betaGR may play a more dominant role in particle internalization on professional phagocytes. Binding of zymosan to RAW 264.7 Mphi expressing SIGNR1 resulted in TNF-alpha production. Treatment of RAW 264.7 Mphi expressing SIGNR1, which express low levels of betaGR, with Beta-Glucans had little effect on binding or TNF-alpha production, indicating that there was no absolute requirement for betaGR in this process. These studies have identified SIGNR1 as a major MR for fungal and other pathogens present on specific subsets of Mphi.
D Hoole - One of the best experts on this subject based on the ideXlab platform.
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dietary β glucan stimulate complement and c reactive protein acute phase responses in common carp cyprinus carpio during an aeromonas salmonicida infection
Fish & Shellfish Immunology, 2013Co-Authors: Nicolas Pionnier, Alberto Falco, Patrick Frost, Joanna J Miest, Ilgiz Irnazarow, Annette K Shrive, D HooleAbstract:The effect of Beta-Glucans as feed additive on the profile of C-reactive protein (CRP) and complement acute phase responses was studied in common carp Cyprinus carpio after exposition to a bacterial infection with Aeromonas salmonicida. Carp were orally administered with Beta-Glucan (MacroGard (R)) for 14 days with a daily Beta-Glucan intake of 6 mg per kg body weight. Fish were then intraperitoneally injected with either PBS or 1 x 10(8) bacteria per fish and sampled at time 0, 6, 12, 24, 48, 72, 96 and 120 h post-injection (p.i.) for serum and head kidney, liver and mid-gut tissues. CRP levels and complement activity were determined in the serum samples whilst the gene expression profiles of CRP and complement related genes (crp1, crp2, c1r/s, bf/c2, c3 and masp2) were analysed in the tissues by quantitative PCR. Results obtained showed that oral administration of Beta-Glucan for 14 days significantly increased serum CRP levels up to 2 fold and serum alternative complement activity (ACP) up to 35 fold. The bacterial infection on its own (i.e. not combined with a Beta-Glucan feeding) did have significant effects on complement response whilst CRP was not detectably induced during the carp acute phase reaction. However, the combination of the infection and the Beta-Glucan feeding did show significant effects on both CRP and complement profiles with higher serum CRP levels and serum ACP activity in the Beta-Glucan fed fish than in the control fed fish. In addition, a distinct organ and time dependent expression profile pattern was detected for all the selected genes: a peak of gene expression first occurred in the head kidney tissue (6 h p.i. or 12 h p.i.), then an up-regulation in the liver several hours later (24 h p.i.) and finally up- or down-regulations in the mid-gut at 24 h p.i. and 72 h p.i. In conclusion, the results of this study suggest that MacroGard (R) stimulated CRP and complement responses to A. salmonicida infection in common carp.
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reduced inflammatory response to aeromonas salmonicida infection in common carp cyprinus carpio l fed with β glucan supplements
Fish & Shellfish Immunology, 2012Co-Authors: Alberto Falco, Patrick Frost, Joanna J Miest, Nicolas Pionnier, Ilgiz Irnazarow, D HooleAbstract:The objective of the present study was to determine the action of Beta-Glucans as feed additives on the gene expression profile of some inflammatory-related cytokines from common carp (Cyprinus carpio L) during the early stages of a non-lethal bacterial infection with Aeromonas salmonicida. Beta-Glucan (MacroGard (R)), was administered daily to carp (6 mg per kg body weight) in the form of supplemented commercial food pellets for 14 days prior to infection. Control and treated fish were then intraperitoneally injected with PBS or 4 x 10(8) bacteria per fish and were sampled at time 0 and 6 h, 12 h, I day, 3 days and 5 days post-injection. Head kidney and gut were collected and the gene expression patterns for tnf alpha 1, tnf alpha 2, il1 beta, il6 and il10 were analyzed by quantitative PCR. Results obtained showed that treatment with Beta-Glucans generally down-regulated the expression of all measured genes when compared to their corresponding controls. After injection, highest changes in the gene expression levels were obtained at 6 h: particularly, in head kidney there was higher up-regulation of tnfa1 and tnfa2 in infected fish fed Beta-Glucans in comparison to control feed: however, in gut there was a significant down-regulation of tnf alpha 1, tnf alpha 2, il1 beta and il6 in infected fish fed Beta-Glucans. Analysis of carp specific antibodies against A. salmonicida 30 days after injection revealed their levels were reduced in the infected Beta-Glucan group. In conclusion, a diet supplemented with Beta-Glucan (MacroGard (R)) reduced the gene expression levels of some inflammation-related cytokines in common carp. Such a response appears to be dependent of organ studied and therefore the immunostimulant may be preventing an acute and potential dangerous response in gut, whilst enhancing the inflammatory response in head kidney when exposed to A. salmonicida
Geoffrey B Fincher - One of the best experts on this subject based on the ideXlab platform.
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hyphal cell walls from the plant pathogen rhynchosporium secalis contain 1 3 1 6 β d glucans galacto and rhamnomannans 1 3 1 4 β d glucans and chitin
FEBS Journal, 2009Co-Authors: Filomena Pettolino, Maria Hrmova, Antony Bacic, Izumi Sasaki, Alisa Turbic, Sarah M Wilson, Geoffrey B FincherAbstract:A procedure has been developed for the isolation of cell walls from the hyphae of the causal agent for barley leaf scald, Rhynchosporium secalis (Oudem) J.J. Davis. Based primarily on monosaccharide linkage analysis, but also on the limited use of linkage-specific glucan hydrolases and solvent fractionation, the walls consist predominantly of (1,3/1,6)-beta-D-glucans, (1,3;1,4)-beta-D-glucans, galactomannans of (1,2;1,6)-Manp residues and (1,5)-galactofuranosyl [(1,5)-Galf] side chains, rhamnomannans of (1,6)-Manp residues and rhamnopyranosyl [(1,2)-Rhap] side chains, and chitin; the walls also contain approximately 23% (w/w) protein. Electron microscopy shows the presence of distinct inner and outer wall layers. Treatment of wall preparations with guanidine hydrochloride dissolves the outer layer and enables separate analysis of the inner and outer walls. The insoluble, inner wall layer is composed of (1,3/1,6)-beta-D-glucans, galacto- and rhamnomannans, (1,3;1,4)-beta-D-glucans and chitin, whereas the soluble outer wall material contains a high proportion of rhamnomannan, and smaller proportions of galactomannan, (1,3;1,4)-beta-D-glucan and (1,3/1,6)-beta-D-glucan with only trace levels of chitin. It was confirmed by immunochemical and enzymatic analysis that at least a portion of the (1,3;1,4)-beta-D-glucan component of the inner wall exists as a (1,3;1,4)-beta-D-glucan. The analyses not only provide information that is important for a complete understanding of the interactions between R. secalis and barley, but they also identify potential targets for the development of fungicides or resistant transgenic barley varieties.
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chemistry biochemistry and biology of 1 3 beta glucans and related polysaccharides
2009Co-Authors: Antony Bacic, Geoffrey B Fincher, A B StoneAbstract:This book presents a comprehensive, systematic and authoritative survey of information about a family of chemically related, but functionally diverse, naturally occurring polysaccharides- the (1-3)-glucans. International contributors describe the chemical and physicochemical properties of these glucans and their derivatives and the molecular biological and structural aspects of the enzymes involved in their formation and breakdown. A detailed analysis of their physiological roles in the various biological situations in which they are found will be provided. Additionally, evolutionary relationships among the family of these glucans will be described. In this title, topics of medical relevance include detailing the glucans' interactions with the immune system and research for cancer therapy applications. Web resource links allow scientists to explore additional beta glucan research. Separate indexes are divided into Species and Subject for enhanced searchability.
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cellulose synthase like cslf genes mediate the synthesis of cell wall 1 3 1 4 beta d glucans
Science, 2006Co-Authors: Rachel A Burton, Bruce A. Stone, Maria Hrmova, Neil J Shirley, Sally Wilson, Andrew Harvey, Anne Medhurst, Ed Newbigin, Antony Bacic, Geoffrey B FincherAbstract:A characteristic feature of grasses and commercially important cereals is the presence of (1,3;1,4)-beta-d-glucans in their cell walls. We have used comparative genomics to link a major quantitative trait locus for (1,3;1,4)-beta-d-glucan content in barley grain to a cluster of cellulose synthase-like CslF genes in rice. After insertion of rice CslF genes into Arabidopsis, we detected (1,3;1,4)-beta-d-glucan in walls of transgenic plants using specific monoclonal antibodies and enzymatic analysis. Because wild-type Arabidopsis does not contain CslF genes or have (1,3;1,4)-beta-d-glucans in its walls, these experiments provide direct, gain-of-function evidence for the participation of rice CslF genes in (1,3;1,4)-beta-d-glucan biosynthesis.
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polysaccharide hydrolases in germinated barley and their role in the depolymerization of plant and fungal cell walls
International Journal of Biological Macromolecules, 1997Co-Authors: Maria Hrmova, Mitali Banik, Andrew J Harvey, Thomas P J Garrett, J N Varghese, P B Hoj, Geoffrey B FincherAbstract:Cell wall degradation is an important event during endosperm mobilization in the germinated barley grain. A battery of polysaccharide and oligosaccharide hydrolases is required for the complete depolymerization of the arabinoxylans and (1 --> 3,1 --> 4)-Beta-Glucans which comprise in excess of 90% by weight of these walls. The (1 --> 3,1 --> 4)-Beta-Glucan endohydrolases release oligosaccharides from their substrate and are probably of central importance for the initial solubilization of the (1 --> 3,1 --> 4)-Beta-Glucans, but Beta-Glucan exohydrolases and beta-glucosidases may be important additional enzymes for the conversion of released oligosaccharides to glucose. The latter enzymes have recently been purified from germinated barley and characterized. There is an increasing body of evidence to support the notion that the (1 --> 3,1 --> 4)-Beta-Glucan endohydrolases from germinated barley evolved from the pathogenesis-related (1 --> 3)-Beta-Glucanases which are widely distributed in plants and which hydrolyse polysaccharides that are abundant in fungal cell walls. Arabinoxylan depolymerization is also mediated by a family of enzymes, but these are less well characterized. (1 --> 4)-beta-Xylan endohydrolases have been purified and the corresponding cDNAs and genes isolated. While the presence of (1 --> 4)-beta-xylan exohydrolases and alpha-L-arabinofuranosidases has been reported many times, the enzymes have not yet been studied in detail. Here, recent advances in the enzymology and physiology of cell wall degradation in the germinated barley grain are briefly reviewed.