994 resultados para Toxicology.
Resumo:
TSV-DM, a basic metalloproteinase with a molecular weight of 110 kDa, was purified from Trimeresurus stejnegeri venom. TSV-DM degraded the A alpha chain of fibrinogen more rapidly than the B beta chain in a dose dependent manner. The cDNA of TSV-DM encode
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A novel toad lysozyme (named BA-lysozyme) was purified from skin secretions of Bufo andrewsi by a three-step chromatography procedure. BA-lysozyme is a single chain protein and the apparent molecular weight is about 15 kDa as judged by SDS-PAGE. The speci
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A novel C-type lectin-like protein, dabocetin, was purified from Daboia russellii siamensis venom. On SDS-polyacrylamide gel electrophoresis, it showed a single band with an apparent molecular weight of 28 kDa and two distinct bands with the apparent mole
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Serine proteases are widely distributed in viperid snake venoms, but rare in elapid snake venoms. Previously, we have identified a fibrinogenolytic enzyme termed OhS1 from the venom of Ophiophagus hannah. The results indicated that OhS1 might be a serine
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Wasp is an important venomous animal that can induce human fatalities. Coagulopathy is a clinical symptom after massive wasp stings, but the reason leading to the envenomation manifestation is still not known. In this paper, a toxin protein is purified and characterized by Sephadex G-75 gel filtration, CM-Sephadex C-25 cationic exchange and fast protein liquid chromatography (FPLC) from the venom of the wasp, Vespa magnifica (Smith). This protein, named magnvesin. contains serine protease-like activity and inhibits blood coagulation. The cDNA encoding magnvesin is cloned from the venom sac cDNA library of the wasp. The deduced protein from the cDNA is composed of 305 amino acid residues. Magnvesin shares 52% identity with allergen serine protease from the wasp Polistes dominulus. Magnvesin exerted its anti-coagulant function by hydrolyzing coagulant factors TF, VII, VIII, IX and X. (c) 2008 Elsevier Ltd. All rights reserved.
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A 50 kDa fibrinogenolytic protease, ohagin, from the venom of Ophiophagus hannah was isolated by a combination of gel filtration, ion-exchange and heparin affinity chromatography. Ohagin specifically degraded the alpha-chain of human fibrinogen and the pr
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An L-amino acid oxidase from Ophiophagus hannah snake venom (Oh-LAAO) was purified by successive gel filtration, ion-exchange and heparin chromatography. Oh-LAAO did not induce platelet aggregation; however, it had potent inhibitory activity on platelet a
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Wasp is an impor tant venomous animal that can induce human fatalities. Aortic thrombosis and cerebral infarction are major clinical symptoms after massive wasp stings but the reason leading to the envenomation manifestation is still not known. In this paper, a toxin protein is purified and characterized by Sephadex G-75 gel filtration, CM-Sephadex C-25 cationic exchange and fast protein liquid chromatography (FPLC) from the venom of the wasp, Vespa magnifica (Smith). This protein, named magnifin, contains phospholipase-like activity and induces platelet aggregation. The cDNA encoding magnifin is cloned from the venom sac cDNA library of the wasp. The predicted protein was deduced from the cDNA with a sequence composed of 337 amino acid residues. Magnifin is very similar to other phospholipase A(1) (PLA(1)), especially to other wasp allergen PLA(1). Magnifin can activate platelet aggregation and induce thrombosis in vivo. The current results proved that PLA(1) in wasp venom could be contributable to aortic thrombosis after massive wasp stings. (c) 2007 Elsevier Ltd. All rights reserved.
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Previous in vivo study demonstrated that beta gamma-CAT, a newly identified non-lens beta gamma-crystallin and trefoil factor complex from frog Bombina maxima skin secretions, possessed potent lethal toxicity on mammals resulted from hypotension and cardi
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In vertebrates, non-lens beta gamma-crystallins are widely expressed in various tissues but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained
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In vertebrates, non-lens beta gamma-crystallins are widely expressed in various tissues, but their functions are unknown. The molecular mechanisms of trefoil factors, initiators of mucosal healing and being greatly involved in tumorigenesis, have remained
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The Ag5 proteins are the most abundant and immunogenic proteins in the venom secretory ducts of stinging insects. An antigen 5-like protein (named tabRTS) composed of 221 amino acid residues was purified and characterized from the salivary glands of the horsefly, Tabanus yao (Diptera, Tabanidae). Its cDNA was cloned from the cDNA library of the horsefly's salivary gland. TabRTS containing the SCP domain (Sc7 family of extracellular protein domain) was found in insect antigen 5 proteins. More interestingly, there is an Arg-Thr-Ser (RTS) disintegrin motif at the C-terminus of tabRTS. The RTS motif is positioned in a loop bracketed by cysteine residues as those found in RTS-disintegrins of Crotalidae and Viperidae snake venoms, which act as angiogenesis inhibitors. Endothelial Cell Tube formation assay in vitro and chicken chorioallantoic membrane (CAM) angiogenesis assay in vivo were performed as to investigate the effect of tabRTS on angiogenesis. It was found that tabRTS could significantly inhibit angiogenesis in vitro and in vivo. Anti-alpha(1)beta(1) monoclonal antibody could dose-dependently inhibit the anti-angiogenic activity of tabRTS. This result indicated that tabRTS possibly targets the alpha(1)beta(1) integrin to exert the anti-angiogenic activity as snake venom RTS-/KTS-disintegrins do. The current work revealed the first angiogenesis inhibitor protein containing RTS motif from invertebrates, a possible novel type of RTS-disintegrin. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin. was purified by DEAF A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH2-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg, The fibrinopeptides released, identified by HPLC consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it. indicating it is venom serine protease. (C) 2000 Elsevier Science Ltd. All rights reserved.
Resumo:
A phospholipase A(2) (PLA(2)) called jerdoxin, was isolated from Trimeresurus jerdonni snake venom and partially characterized. The protein was purified by three chromatographic steps. SDS-polyacrylamide gel electrophoresis in the presence or absence of dithiothreitol showed that it had a molecular mass of 15 kDa. Jerdoxin had an enzymatic activity of 39.4 mumol/min/mg towards egg yolk phosphatidyl choline (PC). It induced edema in the footpads of mice. In addition, jerdoxin exhibited indirect hemolytic activity. About 97% hemolysis was observed when 2 mug/ml enzyme was incubated for 90 min in the presence of PC and Ca2+. No detectable hemolysis was noticed when PC was not added. Ca2+ was necessary for jerdoxin to exert its hemolytic activity, since only 52% hemolysis was seen when Ca2+ was absent in the reaction mixture. Furthermore, jerdoxin inhibited ADP induced rabbit platelet aggregation and the inhibition was dose dependent with an IC50 of 1.0 muM. The complete amino acid sequence of jerdoxin deduced from cDNA sequence shared high homology with other snake venom PLA(2)s, especially the D49 PLA(2)s. Also, the residues concerned to Ca2+ binding were conserved. This is the first report of cDNA sequence of T jerdonii venom PLA(2). (C) 2002 Elsevier Science Ltd. All rights reserved.
Resumo:
TMVA, a novel C-type lectin-like protein that induces platelet aggregation in a dose-dependent manner, was purified from the venom of Trimeresurus mucrosquamatus. It consists of two subunits, alpha (15,536 Da) and beta (14,873 Da). The mature amino acid sequences of the a (135 amino acids) and beta subunits (123 amino acids) were deduced from cloned cDNAs. Both of the sequences show great similarity to C-type lectin-like venom proteins, including a carbohydrate recognition domain. The cysteine residues of TMVA are conserved at positions corresponding to those of flavocetin-A and convulxin, including the additional Cys135 in the alpha subunit and Cys3 in the beta subunit. SDS-PAGE, mass spectrometry analysis and amino acid sequence showed that native TMVA exists as two convertible multimers Of (alphabeta)(2) and (alphabeta)(4) with molecular weights of 63,680 and 128,518 Da, respectively. The (alphabeta)(2) complex is stabilized by an interchain disulfide bridge between the two alphabeta-heterodimers, whereas the stabilization of the (alphabeta)(4) complex seems to involve non-covalent interactions between the (alphabeta)(2) complexes. (C) 2002 Elsevier Science Ltd. All rights reserved.