Navegando por Palavras-chave "Spatoglossum schroederi"

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    Fucan inhibits Chinese hamster ovary cell (CHO) adhesion to fibronectin by binding to the extracellular matrix
    (Georg Thieme Verlag Kg, 2005-07-01) Rocha, Hugo Alexandre de Oliveira [UNIFESP]; Franco, Celia Regina Cavichiolo; Trindade, Edvaldo da Silva; Veiga, Silvio Sanches; Leite, Edda Lisboa; Nader, Helena Bonciani [UNIFESP]; Dietrich, Carl Peter [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Univ Fed Rio Grande Norte; Univ Fed Parana
    In recent years, sulfated fucans have emerged as an important class of natural biopolymers. in this study, the anti-adhesive activity of a fucan from the brown seaweed Spatoglossum schroederi was analyzed using tumorigenic cells: wild-type Chinese hamster ovary cells (CHO-K1) and the mutant type deficient in xylosyltransferase (CHO-745). Fibronectin (FN) was used as substrate for cell attachment. for both cell types, this fucan has shown a dose-dependent anti-adhesive effect, reaching saturation at around 400 mu g/mL. This effect was abolished by desulfation of the fucan. in addition, this polymer exhibited the highest inhibitory effect in comparison to other sulfated polysaccharides. the fucan was biotinylated and used as a probe to identify its action sites. Biotinylated fucan was detected in the extracellular matrix environment by confocal microscopy and flow cytometric analysis, but not at the cell surface. the results suggest that the fucan shows anti-adhesive activity by binding directly to FN, and blocking FN sites that are recognized by cell surface ligands, possibly the integrin family.
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    A non-anticoagulant heterofucan has antithrombotic activity in vivo
    (Georg Thieme Verlag Kg, 2008-06-01) Barroso, Edjane Maria de Azevedo; Costa, Leandro Silva; Medeiros, Valquiria Pereira de [UNIFESP]; Cordeiro, Sara Lima; Costa, Mariana Santana Santos Pereira; Franco, Celia Regina Cavichiolo; Nader, Helena Bonciani [UNIFESP]; Leite, Edda Lisboa; Rocha, Hugo Alexandre de Oliveira; Univ Fed Rio Grande do Norte; Universidade Federal de São Paulo (UNIFESP); Univ Fed Parana
    Fucan is a term used to denominate a family of sulfated L-fucose-rich polysaccharides. the brown alga Spatoglossum schroederi(Dictyotaceae) has three heterofucans namely fucan A, B and C. the 21 kDa fucan A is composed of a core of a beta (1-3) glucuronic acid-containing oligosaccharide of 4.5 kDa with branches at C4 of the fucose chains a (1-3) linked. the fucose is mostly substituted at C4 with a sulfate group and at C2 with chains of beta (1-4) xylose. This fucan has neither anticoagulant (from from 0.1 to 100 mu g) nor hemorrhagic activities (from 50 to 800 mu g/mL). the antithrombotic test in vivo showed that fucan A has no activity in any of the concentrations (from 0.2 to 20 mu g/g/day) tested 1 h after polysaccharide administration. However, when fucan A was injected endovenously 24 h before the ligature of the venae cavae, we observed a dose-dependent effect, reaching saturation at around 20 mu g/g of rat weight. in addition, this effect is also time-dependent, reaching saturation around 16 h after fucan administration. in addition, regardless of the administration route, fucan A displayed antithrombotic activity. the exception was the oral pathway. of particular importance was the finding that fucan A stimulates the synthesis of an antithrombotic heparan sulfate from endothelial cells like heparin. the hypothesis has been raised that the in vivo antithrombotic activity of fucan A is related to the increased production of this heparan. Taken together with the fact that the compound is practically devoid of anticoagulant and hemorrhagic activity, the data suggest that it may be an ideal antithrombotic agent in vivo.