Navegando por Palavras-chave "caterpillar"

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    In vivo characterization of Lopap, a prothrombin activator serine protease from the Lonomia obliqua caterpillar venom
    (Elsevier B.V., 2001-06-01) Reis, C. V.; Farsky, SHP; Fernandes, B. L.; Santoro, M. L.; Oliva, MLV; Mariano, M.; Chudzinski-Tavassi, A. M.; FAPESP; Universidade de São Paulo (USP); Butantan Inst; Universidade Federal de São Paulo (UNIFESP)
    Increasing occurrence of hemorrhagic syndrome in man, caused by contact with Lonomia obliqua caterpillars, has been reported in Southern Brazil in the past 10 years. the L. obliqua venom causes a severe consumptive coagulopathy, which can lead to hemorrhagic syndrome. L. obliqua prothrombin activator protease (Lopap) is a 69-kDa prothrombin activator serine protease isolated from L. obliqua caterpillar bristle extract, which is able to evoke thrombus formation, unclottable blood, and fibrinogen depletion when injected into the blood stream of rats. the purified protein generated thrombin from prothrombin, able to clot purified human fibrinogen and plasma. A decrease in platelet count and inhibition of collagen-induced platelet aggregation were observed, as well as leukocyte infiltration in the lungs. Ln addition, we observed congestion and hemorrhage in renal glomeruli and necrosis in renal distal tubules. These data support the hypothesis that Lopap contributes to the clinical syndrome caused by human contact with L. obliqua, most probably through prothrombin activation, resulting in a consumption coagulopathy. (C) 2001 Elsevier B.V. All rights reserved.
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    A prothrombin activator serine protease from the Lonomia obliqua caterpillar venom (Lopap) biochemical characterization
    (Elsevier B.V., 2001-06-01) Reis, C. V.; Portaro, FCV; Andrade, S. A.; Fritzen, M.; Fernandes, B. L.; Sampaio, CAM; Camargo, ACM; Chudzinski-Tavassi, A. M.; FAPESP; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    Lonomia obliqua venom causes a severe consumptive coagulopathy, which can lead to a hemorrhagic syndrome. the crude bristles extract displays a procoagulant activity due to a Factor X and to a prothrombin activating activity. Here, we describe a 69 kDa prothrombin activator serine protease purified from L. obliqua caterpillar bristle extract using gel filtration (Sephadex G 75) and HPLC (C-4 column). the purified protein was able to activate prothrombin in a dose-dependent manner, and calcium ions increased this activity. the prothrombin-derived fluorogenic peptide (Abz-YQTFFNPRTGSQ-EDDnp) had its main cleavage site at the Arg-Thr bond. the kinetic parameters obtained for this substrate were K-mapp. of 4.5 muM, k(cat) of 5.32 s(-1), and a k(cat)/K-mapp of 1.2 x 10(6) M-1 s(-1). the prothrombin fragments generated by the purified enzyme corresponded to the molecular masses of prethrombin 2, fragment 1, fragment 2, and thrombin as seen in SDS-PAGE. the thrombin generated was able to clot purified fibrinogen. the partial amino acid sequence of the purified protein, named Lopap (L. obliqua prothrombin activator protease), showed no similarity to any known prothrombin activator. (C) 2001 Elsevier B.V. All rights reserved.
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    Purification of a phospholipase A(2) from Lonomia obliqua caterpillar bristle extract
    (Elsevier B.V., 2006-04-21) Seibert, C. S.; Tanaka-Azevedo, A. M.; Santoro, M. L.; Mackessy, S. P.; Torquato, RJS; Lebrun, I; Tanaka, A. S.; Sano-Martins, I. S.; Inst Butanan; Univ No Colorado; Universidade Federal de São Paulo (UNIFESP)
    Lonomia obliqua caterpillar bristle extract induces both direct and indirect hemolytic activity on human and rat washed erythrocytes, and provokes intravascular hemolysis in Wistar rats. Indirect hemolytic activity is assumed to be caused by a phospholipase A(2) (PLA(2)) present in this extract, and this investigation was initiated in order to characterize this enzyme. Phospholipase A, activity of crude extract was inhibited by both a PLA(2)-specific inhibitor (pBpb) and the metal ion chelator EDTA. L. obliqua PLA(2) was purified by liquid chromatography from the crude bristle extract and had a molecular mass of 15 kDa and a pI of 5.9: its N-terminal sequence showed high homology to a sequence of a putative PLA(2) obtained from a cDNA library of L. obliqua bristles, and it is tentatively placed among Group III phospholipases A(2). This enzyme was stable at 4 degrees C sensitive to higher temperatures, and its maximum catalytic activity was at pH 8.0. L. obliqua PLA(2) induced hemolysis only when incubated with exogenous lecithin. Thus, the PLA(2) purified herein appears to be responsible for the indirect hemolytic activity of the crude bristle extract. (c) 2006 Elsevier Inc. All rights reserved.