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Caracterização do conteúdo de beta-glicana em genótipos brasileiros de aveia branca em diferentes ambientes; Caracterization of beta-glucan content on oat brazilian genotypes under different enviroments

Severo, Martim Fogaça
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
46.33%
A beta glicana, [(1→3)(1→4)‑β‑D‑glicana] é um dos componentes das paredes celulares dos cereais, sendo o principal constituinte da fibra solúvel em aveia branca (Avena sativa L.). Suas características funcionais trazem benefícios para pessoas que realizam uma dieta rica em beta-glicanas, como redução do colesterol, diminuição do teor de glicose e insulina no sangue, prevenção de câncer do cólon do intestino e prevenção de doenças cardíacas. Desta forma, o melhoramento genético tem buscado selecionar genótipos de aveia com maior conteúdo de beta-glicana e com expressão estável nos ambientes de cultivo. Este trabalho teve como objetivo caracterizar genótipos brasileiros de aveia branca quanto ao conteúdo de beta-glicana nos grãos e quanto à estabilidade deste em diferentes ambientes. Em 2010 e 2011 15 genótipos de aveia, desenvolvidos pelo Programa de Melhoramento de Aveia da Universidade Federal do Rio Grande do Sul (UFRGS), foram avaliados em seis ambientes, constituídos por locais e épocas de cultivo diferentes, a fim de caracterizar o conteúdo de beta-glicanas e outras características químicas e físicas dos grãos. Os resultados mostraram que a o conteúdo de beta-glicana é muito semelhante entre os genótipos da UFRGS analisados...

Anti-clastogenic effect of beta-glucan extracted from barley towards chemically induced DNA damage in rodent cells

Angeli, J. P. F.; Ribeiro, L. R.; Bellini, M. F.; Mantovani, M. S.
Fonte: Hodder Arnold, Hodder Headline Plc Publicador: Hodder Arnold, Hodder Headline Plc
Tipo: Artigo de Revista Científica Formato: 319-324
ENG
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beta-Glucan (BG) was tested in vitro to determine its potential clastogenic and/or anti-clastogenic activity, and attempts were made to elucidate its possible mechanism of action by using combinations with an inhibitor of DNA polymerase. The study was carried out on cells deficient (CHO-k1) and cells proficient (HTC) in phases I and II enzymes, and the DNA damage was assessed by the chromosomal aberration assay. BG did not show a clastogenic effect, but was anti-clastogenic in both cell lines used, and at all concentrations tested (2.5, 5 and 10 mg/mL) in combination with damage inducing agents (methylmethane sulfonate in cell line CHO-k1, and methylmethane sulfonate or 2-aminoanthracene in cell line HTC). BG also showed a protective effect in the presence of a DNA polymerase beta inhibitor (cytosine arabinoside-3-phosphate, Ara-C), demonstrating that BG does not act through an anti-mutagenic mechanism of action involving DNA polymerase beta.

Protective effects of beta-glucan extracted from Agaricus brasiliensis against chemically induced DNA damage in human lymphocytes

Angeli, J. P. F.; Ribeiro, L. R.; Gonzaga, M. L. C.; Soares, S. de A.; Ricardo, M. P. S. N.; Tsuboy, M. S.; Stidl, R.; Knasmueller, S.; Linhares, R. E.; Mantovani, M. S.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 285-291
ENG
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46.17%
beta-Glucans (BGs) are polysaccharides that are found in the cell walls of organisms such as bacteria, fungi, and some cereals. The objective of the present study was to investigate the genotoxic and antigenotoxic effects of BG extracted from the mushroom Agaricus brasiliensis (=Agaricus blazei Murrill ss. Heinemann). The mutagenic activity of BG was tested in single-cell gel electrophoresis assays with human peripheral lymphocytes. In addition, the protective effects against the cooked food mutagen 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and (+/-)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), which is the main metabolite of B[a]P, and against ROS (H2O2)-induced DNA damage, were studied. The results showed that the compound itself was devoid of mutagenic activity, and that a significant dose-dependent protective effect against damage induced by hydrogen peroxide and Trp-P-2 occurred in the dose range 20-80 mu g/ml. To investigate the prevention of Trp-P-2-induced DNA damage, a binding assay was carried out to determine whether BG inactivates the amine via direct binding. Since no such interactions were observed, it is likely that BG interacts with enzymes involved in the metabolism of the amine.

beta-glucans in promoting health: Prevention against mutation and cancer

Mantovani, Mario S.; Bellini, Marilanda F.; Angeli, Jose Pedro F.; Oliveira, Rodrigo J.; Silva, Ariane F.; Ribeiro, Lucia R.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 154-161
ENG
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The polysaccharides beta-glucans occur as a principal component of the cellular walls. Some microorganisms, such as yeast and mushrooms, and also cereals such as oats and barley, are of economic interest because they contain large amounts of beta-glucans. These substances stimulate the immune system, modulating humoral and cellular immunity, and thereby have beneficial effect in fighting infections (bacterial, viral, fungal and parasitic). beta-Glucans also exhibit hypocholesterolemic and anticoagulant properties. Recently, they have been demonstrated to be anti-cytotoxic, antimutagenic and anti-tumorogenic, making them promising candidate as pharmacological promoters of health. (C) 2008 Elsevier B.V. All rights reserved.

Evaluation of the antigenotoxicity of polysaccharides and beta-glucans from Agaricus blazei, a model study with the single cell gel electrophoresis/Hep G2 assay

Friedmann Angeli, Jose Pedro; Ribeiro, Lucia Regina; Camelini, Carla M.; de Mendonca, Margarida M.; Mantovani, Mario Sergio
Fonte: Academic Press Inc. Elsevier B.V. Publicador: Academic Press Inc. Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 699-703
ENG
Relevância na Pesquisa
56.79%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); The mushroom Agaricus blazei (Agaricus brasiliensis) has been drawing attention because of its medicinal properties. Among its isolated compounds, special consideration is given to beta-glucans, which are cell wall polysaccharides. The aim of the present work was to determine the genotoxic and/or antigenotoxic effects of the total polysaccharides of this mushroom and beta-glucans, both extracted at different stages of fruiting body maturity (immature. mature stage with immature spores and mature stage with mature spores). beta-glucan genotoxicity was examined using the comet assay in the HepG2 cell line. Additionally, the protective effect of total polysaccharides and beta-glucans was tested against H(2)O(2), bleomycin and doxorubicin. The results demonstrated that total polysaccharides and beta-glucans had no genotoxic effects. on the contrary, they protected DNA against damage caused by the three inducers used. However, total polysaccharides had limited protective effects while being ineffective against doxorubicin. Interestingly, the largest protective effect was seen with extracts from the ripest stages and in the absence of isolated beta-glucan. (C) 2009 Elsevier B.V. All rights reserved.

Ação de beta-glucanos em leitões recém-desmamados alimentados com dietas com diferentes densidades nutricionais

Saleh, Mayra Anton Dib
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Tese de Doutorado Formato: vii, 78 f. : tabs.
POR
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36.86%
Pós-graduação em Zootecnia - FMVZ; A nutrição exerce influência na modulação do sistema imune e na melhoria da resistência dos animais à infecção, visto que os nutrientes são necessários para a multiplicação celular durante a resposta imune e síntese de moléculas relacionadas à comunicação celular. Dois experimentos foram conduzidos com leitões desmamados aos 21 dias de idade e submetidos ao desafio com 150 μg kg-1 PV de lipopolissacarídeo (LPS) de Escherichia coli sorotipo 055:B5. Objetivou-se avaliar efeitos da adição de beta-glucanos originários da levedura Saccharomyces cerevisiae (0 e 300 ppm) em dietas com densidade nutricional baixa e elevada (3300 e 3450 kcal de EM kg-1) sobre o desempenho (Experimento I) e morfometria intestinal (altura de vilosidades: AV, profundidade de criptas: PC, relação AV:PC e área das placas de Peyer: PP) e peso de órgãos (fígado, timo e baço) dos leitões (Experimento II). No experimento I foram utilizados 96 leitões em delineamento de blocos ao acaso (oito repetições), em esquema fatorial 2 x 2 (2 níveis de beta-glucanos x 2 densidades nutricionais), enquanto no segundo experimento, 40 leitões foram distribuídos em delineamento de blocos ao acaso (cinco repetições) com arranjo fatorial dos tratamentos 2 x 2 x 2 (2 níveis de beta-glucanos x 2 densidades nutricionais x 2 épocas de abate: uma semana antes da primeira inoculação com LPS e uma semana após a segunda inoculação com LPS). Nos experimentos foram realizadas análises estatísticas dos dados utilizando o procedimento GLM (Experimento I) e análise multivariada (Experimento II) do SAS...

Cyclic [beta]-1,6-1,3-Glucans of Bradyrhizobium japonicum USDA 110 Elicit Isoflavonoid Production in the Soybean (Glycine max) Host.

Miller, K. J.; Hadley, J. A.; Gustine, D. L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1994 EN
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36.72%
High levels of cyclic [beta]-1,6-1,3-glucans (e.g. 0.1 mg mg-1 of total protein) are synthesized by free-living cells as well as by bacteroids of Bradyrhizobium japonicum USDA 110 (K.J. Miller, R.S. Gore, R. Johnson, A.J. Benesi, V.N. Reinhold [1990] J Bacteriol 172: 136-142; R.S. Gore and K.J. Miller [1993] Plant Physiol 102: 191-194). These molecules share structural features with glucan fragments isolated from the mycelial cell wall of the soybean (Glycine max) pathogen Phytophthora megasperma. These latter glucans have been shown to be potent elicitors (at nanogram levels) of the phytoalexin glyceollin in G. max. Using the well-characterized soybean cotyledon bioassay, we now show that the cyclic [beta]-1,6-1,3-glucans of B. japonicum USDA 110 are also biologically active elicitors of glyceollin production (but at microgram levels). We further show that both classes of [beta]-glucans elicit the production of the isoflavone daidzein within soybean cotyledon wound droplets.

Beta-glucan synthesis in Bradyrhizobium japonicum: characterization of a new locus (ndvC) influencing beta-(1-->6) linkages.

Bhagwat, A A; Gross, K C; Tully, R E; Keister, D L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1996 EN
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36.68%
Bradyrhizobium japonicum synthesizes periplasmic cyclic beta-(1-->3),beta-(1-->6)-D-glucans during growth in hypoosmotic environments, and evidence is growing that these molecules may have a specific function during plant-microbe interactions in addition to osmoregulation. Site-directed Tn5 mutagenesis of the DNA region upstream of ndvB resulted in identification of a new gene (ndvC) involved in beta-(1--> 3), beta-(1-->6)-glucan synthesis and in nodule development. The predicted translation product was a polypeptide (ca. 62 kDa) with several transmembrane domains. It contained a sequence characteristic of a conserved nucleoside-sugar-binding motif found in many bacterial enzymes and had 51% similarity with a beta-glucanosyltransferase from Candida albicans. B. japonicum carrying a Tn5 insertion in ndvC resulted in synthesis of altered cyclic beta-glucans composed almost entirely of beta-(1--> 3)-glycosyl linkages. The mutant strain was only slightly sensitive to hypoosmotic growth conditions compared with the ndvB mutant, but it was severely impaired in symbiotic interactions with soybean (Glycine max). Nodulation was delayed by 8 to 10 days, and many small nodule-like structures apparently devoid of viable bacteria were formed. This finding suggests that the structure of the beta-glucan molecule is important for a successful symbiotic interaction...

Cyclic beta-glucans of members of the family Rhizobiaceae.

Breedveld, M W; Miller, K J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /06/1994 EN
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Cyclic beta-glucans are low-molecular-weight cell surface carbohydrates that are found almost exclusively in bacteria of the Rhizobiaceae family. These glucans are major cellular constituents, and under certain culture conditions their levels may reach up to 20% of the total cellular dry weight. In Agrobacterium and Rhizobium species, these molecules contain between 17 and 40 glucose residues linked solely by beta-(1,2) glycosidic bonds. In Bradyrhizobium species, the cyclic beta-glucans are smaller (10 to 13 glucose residues) and contain glucose linked by both beta-(1,6) and beta-(1,3) glycosidic bonds. In some rhizobial strains, the cyclic beta-glucans are unsubstituted, whereas in other rhizobia these molecules may become highly substituted with moieties such as sn-1-phosphoglycerol. To date, two genetic loci specifically associated with cyclic beta-glucan biosynthesis have been identified in Rhizobium (ndvA and ndvB) and Agrobacterium (chvA and chvB) species. Mutants with mutations at these loci have been shown to be impaired in their ability to grow in hypoosmotic media, have numerous alterations in their cell surface properties, and are also impaired in their ability to infect plants. The present review will examine the structure and occurrence of the cyclic beta-glucans in a variety of species of the Rhizobiaceae. The possible functions of these unique molecules in the free-living bacteria as well as during plant infection will be discussed.

Solubilization of beta-glucan synthases from the membranes of cultured ryegrass endosperm cells.

Henry, R J; Stone, B A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/06/1982 EN
Relevância na Pesquisa
36.75%
beta-Glucan synthases were solubilized by treating membrane preparations from suspension-cultured ryegrass (lolium multiflorum) endosperm cells with detergents. Of the seven detergents tested only digitonin and octyl glucoside dissociated active synthases from the membranes. The digitonin-solubilized enzymes produced 1,4-beta-glucans and 1,3:1,4-beta-glucans, whereas the digitonin-insoluble enzymes produced, in addition, 1,3-beta-glucans. Chromatography of the digitonin-solubilized beta-glucan synthases on DEAE-Sepharose resulted in their partial purification. The octyl glucoside-solubilized enzymes produced more 1,3-beta-glucans than did the membrane-bound preparations. These results suggest that the 1,3-beta-glucan synthase is a separate enzyme and is not involved in 1,3:1,4-beta-glucan synthesis. Digitonin not only dissociated synthases from the membranes, but also stimulated synthase activity. This effect may be related to the inhibition by digitonin of glucosyl transfer from UDP-glucose to form steryl glucosides.

Involvement of [beta]-glucans in the wide-spectrum antimicrobial activity of Williopsis saturnus var. mrakii MUCL 41968 killer toxin.

Guyard, Cyril; Dehecq, Eric; Tissier, Jean-Pierre; Polonelli, Luciano; Dei-Cas, Eduardo; Cailliez, Jean-Charles; Menozzi, Franco D.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/2002 EN
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46.88%
BACKGROUND: Williopsis saturnus var. mrakii MUCL 41968 secretes a 85-kDa glycoprotein killer toxin (WmKT) that displays a cytocidal activity against a wide range of microorganisms, making WmKT a promising candidate for the development of new antimicrobial molecules. Although the killing mechanism of WmKT is still unknown, the toxin was recently proposed to bind to the surface of sensitive microorganisms through the recognition of beta-glucans. Indeed, Saccharomyces cerevisiae strains sensitive to the toxin become resistant when mutated in their beta-glucan synthesis pathway. MATERIALS AND METHODS: To investigate the interaction of WmKT with beta-glucans, we examined in agar diffusion assays the WmKT activity in the presence of enzymes displaying beta-glucanase activity. The toxin activity was also investigated using spheroplasts derived from sensitive yeast cells. The hydrolytic activity of WmKT was studied using specific glucosidase inhibitors as well as various sugar molecules covalently linked to p-nitrophenyl as potential substrates. Finally, the ultrastructural modifications induced by WmKT activity on sensitive yeasts were assessed by scanning electron microscopy. RESULTS: The data reported here support the hypothesis that WmKT binds to sensitive cells using surface-exposed beta-glucans. Indeed beta-glucanase exerts an antagonistic effect on WmKT activity and spheroplasts derived from WmKT-sensitive yeast cells are shown to be resistant to WmKT...

Beta-glucans in the treatment of diabetes and associated cardiovascular risks

Chen, Jiezhong; Raymond, Kenneth
Fonte: Dove Medical Press Publicador: Dove Medical Press
Tipo: Artigo de Revista Científica
Publicado em /12/2008 EN
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46.69%
Diabetes mellitus is characterized by high blood glucose level with typical manifestations of thirst, polyuria, polydipsia, and weight loss. It is caused by defects in insulin-mediated signal pathways, resulting in decreased glucose transportation from blood into muscle and fat cells. The major risk is vascular injury leading to heart disease, which is accelerated by increased lipid levels and hypertension. Management of diabetes includes: control of blood glucose level and lipids; and reduction of hypertension. Dietary intake of beta-glucans has been shown to reduce all these risk factors to benefit the treatment of diabetes and associated complications. In addition, beta-glucans also promote wound healing and alleviate ischemic heart injury. However, the mechanisms behind the effect of beta-glucans on diabetes and associated complications need to be further studied using pure beta-glucan.

The Effect of Mushroom Beta-Glucans from Solid Culture of Ganoderma lucidum on Inhibition of the Primary Tumor Metastasis

Chen, Shiu-Nan; Chang, Ching-Sheng; Hung, Ming-Hsin; Chen, Sherwin; Wang, William; Tai, Cheng-Jeng; Lu, Chung-Lun
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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46.35%
This study evaluates the effect of mushroom beta-glucans (MBGS) derived from solid culture of Ganoderma lucidum on tumor inhibition by examining size of the primary tumor and rate of metastasis in Lewis lung carcinoma (LLC) bearing mice (C57BL/6), given oral administration of MBGS with radiation therapy. A previous result showed that MBGS enhances NK cell-mediated cytotoxicity in mice without LLC bearing in advance. Furthermore, applications of MBGS in conjunction with radiation therapy were effective in controlling tumor growth, and rate of metastasis, life threatening, and can potentially serve as a protective factor for wounds and hair loss that resulted from the overgrowth of primary tumor in LLC bearing mice.

Immune-modulatory effects of dietary Yeast Beta-1,3/1,6-D-glucan

Stier, Heike; Ebbeskotte, Veronika; Gruenwald, Joerg
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
Publicado em 28/04/2014 EN
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36.82%
Beta-glucans are a heterogeneous group of natural polysaccharides mostly investigated for their immunological effects. Due to the low systemic availability of oral preparations, it has been thought that only parenterally applied beta-glucans can modulate the immune system. However, several in vivo and in vitro investigations have revealed that orally applied beta-glucans also exert such effects. Various receptor interactions, explaining possible mode of actions, have been detected. The effects mainly depend on the source and structure of the beta-glucans. In the meantime, several human clinical trials with dietary insoluble yeast beta-glucans have been performed. The results confirm the previous findings of in vivo studies. The results of all studies taken together clearly indicate that oral intake of insoluble yeast beta-glucans is safe and has an immune strengthening effect.

Cellulose synthase-like CslF genes mediate the synthesis of cell wall (1,3;1,4)-beta-D-glucans

Burton, R.; Wilson, S.; Hrmova, M.; Harvey, A.; Shirley, N.; Medhurst, A.; Stone, B.; Newbigin, E.; Bacic, A.; Fincher, G.
Fonte: Amer Assoc Advancement Science Publicador: Amer Assoc Advancement Science
Tipo: Artigo de Revista Científica
Publicado em //2006 EN
Relevância na Pesquisa
46.56%
A characteristic feature of grasses and commercially important cereals is the presence of (1,3;1,4)-ß-D-glucans in their cell walls. We have used comparative genomics to link a major quantitative trait locus for (1,3;1,4)-ß-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)-ß-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)-ß-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)-ß-D-glucan biosynthesis.; Rachel A. Burton, Sarah M. Wilson, Maria Hrmova, Andrew J. Harvey, Neil J. Shirley, Anne Medhurst, Bruce A. Stone, Edward J. Newbigin, Antony Bacic, Geoffrey B. Fincher

Exploring the evolution of (1,3;1,4)-β-D-glucans in plant cell walls: comparative genomics can help!; Exploring the evolution of (1,3;1,4)-beta-D-glucans in plant cell walls: comparative genomics can help!

Fincher, G.
Fonte: Current Biology Ltd Publicador: Current Biology Ltd
Tipo: Artigo de Revista Científica
Publicado em //2009 EN
Relevância na Pesquisa
46.77%
A key distinguishing feature of the grasses is that their cell walls contain (1,3;1,4)-beta-D-glucans, which are distributed almost exclusively within the Poaceae. The identification of genes that mediate in (1,3;1,4)-beta-D-glucan biosynthesis has been possible through relatively recent genome sequencing programmes and comparative genomics techniques. The evolution of a single new gene appears to have been sufficient for the first synthesis of (1,3;1,4)-beta-D-glucans and there is compelling evidence that existing hydrolytic enzymes were adapted for the specific hydrolysis of the polysaccharide during wall turnover or degradation. Manipulation of the expression levels of genes involved in (1,3;1,4)-beta-D-glucan synthesis is likely to provide opportunities to enhance the value of grasses and cereals in commercial applications such as human nutrition and biofuel production.; Geoffrey B. Fincher; Crown Copyright © 2009 Published by Elsevier Ltd. All rights reserved.

The barley genome sequence assembly reveals three additional members of the CslF (1,3;1,4)-β-glucan synthase gene family; The barley genome sequence assembly reveals three additional members of the CslF (1,3;1,4)-beta-glucan synthase gene family

Schreiber, M.; Wright, F.; MacKenzie, K.; Hedley, P.E.; Schwerdt, J.G.; Little, A.; Burton, R.A.; Fincher, G.B.; Marshall, D.; Waugh, R.; Halpin, C.
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em //2014 EN
Relevância na Pesquisa
46.35%
An important component of barley cell walls, particularly in the endosperm, is (1,3;1,4)-β-glucan, a polymer that has proven health benefits in humans and that influences processability in the brewing industry. Genes of the cellulose synthase-like (Csl) F gene family have been shown to be involved in (1,3;1,4)-β-glucan synthesis but many aspects of the biosynthesis are still unclear. Examination of the sequence assembly of the barley genome has revealed the presence of an additional three HvCslF genes (HvCslF11, HvCslF12 and HvCslF13) which may be involved in (1,3;1,4)-β-glucan synthesis. Transcripts of HvCslF11 and HvCslF12 mRNA were found in roots and young leaves, respectively. Transient expression of these genes in Nicotiana benthamiana resulted in phenotypic changes in the infiltrated leaves, although no authentic (1,3;1,4)-β-glucan was detected. Comparisons of the CslF gene families in cereals revealed evidence of intergenic recombination, gene duplications and translocation events. This significant divergence within the gene family might be related to multiple functions of (1,3;1,4)-β-glucans in the Poaceae. Emerging genomic and global expression data for barley and other cereals is a powerful resource for characterising the evolution and dynamics of complete gene families. In the case of the CslF gene family...

Interaction of Candida albicans Biofilms with Antifungals: Transcriptional Response and Binding of Antifungals to Beta-Glucans ▿ †

Vediyappan, Govindsamy; Rossignol, Tristan; d'Enfert, Christophe
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
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46.42%
Candida albicans can form biofilms that exhibit elevated intrinsic resistance to various antifungal agents, in particular azoles and polyenes. The molecular mechanisms involved in the antifungal resistance of biofilms remain poorly understood. We have used transcript profiling to explore the early transcriptional responses of mature C. albicans biofilms exposed to various antifungal agents. Mature C. albicans biofilms grown under continuous flow were exposed for as long as 2 h to concentrations of fluconazole (FLU), amphotericin B (AMB), and caspofungin (CAS) that, while lethal for planktonic cells, were not lethal for biofilms. Interestingly, FLU-exposed biofilms showed no significant changes in gene expression over the course of the experiment. In AMB-exposed biofilms, 2.7% of the genes showed altered expression, while in CAS-exposed biofilms, 13.0% of the genes had their expression modified. In particular, exposure to CAS resulted in the upregulation of hypha-specific genes known to play a role in biofilm formation, such as ALS3 and HWP1. There was little overlap between AMB- or CAS-responsive genes in biofilms and those that have been identified as AMB, FLU, or CAS responsive in C. albicans planktonic cultures. These results suggested that the resistance of C. albicans biofilms to azoles or polyenes was due not to the activation of specific mechanisms in response to exposure to these antifungals but rather to the intrinsic properties of the mature biofilms. In this regard...

Formulation and consumer acceptance of cereal bars with functional properties by the incorporation of peptides and β- glucans from Spent Brewer's Yeast

Amorim, Manuela; Pereira, Joana; Pinheiro, Hélder; Pacheco, Maria Teresa; Pintado, Manuela
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
Relevância na Pesquisa
46.36%
The market for functional ingredients and foods has a high growth due to increased awareness and promotion of healthy eating and lifestyle of consumers. Food can be used as vehicle to intake bioactive compounds that provide health benefits and increase people well-being. Thus, cereal bars are a popular and convenient food, which is an ideal carrier to incorporate functional ingredients that promote health and prevent diseases. The design and development of functional foods should not be made based solely on nutritional function without taking into account product properties, such as color, texture, flavor and taste. The sensory properties are the most important attributes for the consumer acceptance, as well as other quality issues such as stability and texture. This work was focused on the formulation and sensory analysis of cereal bars obtained by incorporation of peptides and β-glucans extract obtained via autolysis and hydrolysis of spent brewer’s and presenting biological activities such as, antihypertensive and prebiotic. However, this ingredient results in particular taste and flavor that may constrain the matrix choice and consumer acceptance. The cereal bar was formulated based on oat, rice and corn and added 2% extract. Consumer acceptance tests were performed to test general acceptability in particular for the appearance...

Visão retrospectiva em fibras alimentares com ênfase em beta-glucanas no tratamento do diabetes

Mira, Giane Sprada; Graf, Hans; Cândido, Lys Mary Bileski
Fonte: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo. Faculdade de Ciências Farmacêuticas
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/03/2009 POR
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56.81%
Fibra alimentar refere-se aos componentes de plantas ou carboidratos análogos que são resistentes à digestão e absorção no intestino delgado humano. A American Dietetic Association recomenda ingestão de 20-35g de fibras ao dia. Evidências sugerem que uma dieta rica em fibras traz benefícios à manutenção da saúde, redução de risco e tratamento de doenças crônicas como a obesidade, doenças cardiovasculares, diverticulite e diabetes. As fibras são classificadas de acordo com a sua solubilidade em solúveis e insolúveis, com efeitos fisiológicos distintos. As insolúveis são responsáveis pelo aumento do bolo fecal e diminuição do tempo de trânsito intestinal. As solúveis retardam o esvaziamento gástrico e a absorção de glicose diminuindo a glicemia pós-prandial e reduzem o colesterol sérico devido à sua característica física de conferir viscosidade ao conteúdo luminal. As beta-glucanas são fibras altamente viscosas e seu consumo está relacionado à atenuação da resposta glicêmica e insulínica pós-prandial. A beta-glucana tem efeito sobre a degradação do amido e sobre o carboidrato disponível e conseqüentemente, sobre o índice glicêmico dos alimentos ingeridos. Recomenda-se sua ingestão com o objetivo de modular a glicemia e a necessidade de insulina...