360 resultados para Crotalid Venoms
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In this study, we compared the anti-leishmanial activity of three crotalic venoms (Crotalus durissus terrificus-Cdt, Crotalus durissus cascavella-Cdca, and Crotalus durissus collilineatus-Cdcol). Different concentrations of each venom incubated with Leishmania (Leishmania) amazonensis promastigotes were used. Cdt venom exhibited a higher anti-leishmanial activity (Inhibitory concentration-IC50-value of 4.70 +/- 1.72 mu g/ml) in comparison with that of Cdca venom (IC50 value of 9.41 +/- 1.21 mu g/ml), while Cdcol venom increased parasite numbers in 50% at a concentration of 44.30 +/- 2.18 mu g/ml. In addition, this venom showed a low anti-leishmanial activity in higher concentrations (IC50 value of 281.00 +/- 9.50 mu g/ml). The main fractions of Cdca venom were isolated and assayed under similar conditions used for assessing crude venom. The most active fractions were gyroxin and crotamine that had IC50 values of 3.80 +/- 0.52 mu g/ml and 19.95 +/- 4.21 mu g/ml, respectively. Convulxin also inhibited parasite growth rate, although this effect was not dose-dependent. Crotoxin was the least effective fraction with an IC50 value of 99.80 +/- 2.21 mu g/ml. None of the protein fractions presented cytotoxic effects against J774 cells in culture. In vivo assays using BALB/c mice revealed that crotoxin and crotamine were the main toxic fractions. In conclusion, C. durissus cascavella venom has three main fractions with anti-leishmanial activity. These results open new possibilities to find proteins that might be used as possible agents against cutaneous leishmaniasis.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Cathorops spixii is one of the most abundant venomous fish of the southeastern coast of the State of São Paulo, and consequently causes a great part of the accidents seen there. The accidents affect mainly fishermen, swimmers and tourists and are characterized by punctiform or wide wounds, erythema, edema, pain, sudoresis, indisposition, fever, nausea, vomiting and secondary infection. The objective of this work was to characterize the inflammatory response induced in mice by both venoms (mucus and sting) of the catfish C spixii. Our results demonstrated that both venoms induced a great number of rolling and adherent leukocytes in the post-capillary venules of cremaster muscle of mice, and an increase in the vascular permeability in peritoneal cavity. Mucus induced the recruitment of neutrophils immediately after injection followed later by macrophage infiltration. In contrast, the cellular infiltration elicited by sting venom was rapidly resolved. The peritonitis reaction provoked by venoms was characterized by cytokine (IL-6), chemokines (MCP-1 and KC) or lipid mediator (LTB4) production in the peritoneal cavity. The macrophages from 7-day mucus venom-induced exudates upon in vitro mucus venom stimulation, expressed CD1 Ic x MHC class II and release bioactive IL-12p70. on the other hand, sting venom-elicited peritoneal macrophages lost the ability to differentiate into dendritic cells, following re-stimulation in vitro with sting venom, they do not express CD11c, nor do they exhibit sufficient levels of MHC class II. In conclusion, both types of venoms (mucus or sting) promote inflammatory reaction with different profiles, and the inflammatory reaction induced by the first was characterized by antigen persistence in peritoneal cavity that allowed the activation of phagocytic cells with capacity of antigenic presentation. (C) 2007 Elsevier Ltd. All rights reserved.
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Two myotoxins isolated from B. asper (myotoxin II) and B. nummifer (myotoxin I) snake venoms have been crystallized and their diffraction properties are described. These myotoxins are phospholipase A2 variants which lack enzymatic activity; B. asper myotoxin II is a lysine-49 phospholipase. Crystals were obtained at room temperature by standard hanging-drop vapour diffusion methods. Crystals diffracted to a resolution of 2.8 and 2.3 angstrom, respectively.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The search for biological antitumor agents has been pursued for over half a century. Snake venom has been shown to possess a wide spectrum of biological activities. The objectives of the present review are to evaluate the existing controversies on this subject published in a number of papers and to propose probable explanations for the phenomena observed. We reported our results obtained in a study, in which we evaluated the action of the venoms of Crotalus durissus terrificus and Bothrops jararaca on Ehrlich ascites tumor cells. We noticed an important antitumor effect, mainly with Bothrops jararaca venom, as well as an increase in the functional activity of macrophages. We also observed an increase in the number of mononuclear and polymorphonuclear cells with Bothrops jararaca venom. Considering these findings, we postulate that both Borhrops jararaca and Crotalus durissus terrificus venoms can act directly on tumor cells. In addition, we propose an indirect mechanism, based on the stimulation of the inflammatory response, to inhibit tumor growth and to promote its rejection.
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The profiles of high-performance gel filtration of venoms from Polybia paulista, Polybia ignobilis and Polybia occidentalis occidentalis showed 13 peaks distributed among the three species. These profiles presented similarities that permitted the chromatographic characterization of the genus Polybia and differences that permitted the identification of each species studied. Thus, the comparative analysis of chromatographic profiles of high-performance gel filtration of venoms may be used as an auxiliary tool in taxonomic studies of Polybia wasps.
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The Hymenoptera Aculeata venoms, with few exceptions, have been poorly studied and characterized. Nevertheless, they have raised increasing interest due to their medical importance, since accidents with these insects are fairly frequent in Brazil and may cause severe allergic reactions. The objectives of the present work were the quantitative characterization of the main allergenic enzymes present in the venom of the species Polybia paulista, Polybia ignobilis, Polistes simillimus, and Agelaia pallipes pallipes through biochemical assays for the determination of total protein content, as well as the level of the enzymatic activity of phospholipase, hyaluronidase, acid phosphatase and esterase. These results, in addition to providing biochemical knowledge about the venom of the species in question, also supply studies that allow phylogenetic inferences among them.
Enzymatic variability among venoms from different subspecies of Apis mellifera (Hymenoptera: Apidae)
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The enzymatic variability was analyzed in venom extracts from bees reared in different colonies of the Africanized, A. m. ligustica and A. m. carnica subspecies. The implications of this variation focused on the biochemistry differentiation and immunogenicity of these venoms. The results showed the existence of a huge variability among the subspecies as well as among the colonies for three out of the six tested components - hyaluronidase, acid phosphatase and proteases - suggesting the utilization of these features as possible biochemical markers. Furthermore, although not statistically significant, it was found that the Africanized bee venom presented slightly higher levels of protein content and esterase activity, when compared to the other subspecies. If the esterase plays a role in the pain intensity caused by the sting, as suggested elsewhere, this might suggest a reason for a bigger algogenicity of this venom in relation to that of European bees. On the other hand, A. m. ligustica bees presented the highest levels of proteolytic and acid phosphatase activities, whose functions are not enlightened in Hymenoptera venoms. The A. m. carnica workers presented the highest hyaluronidase and the lowest acid phosphatase activity levels. The extremely variable results among colonies of the same subspecies and among subspecies, for the tested venom components, justify the absence of correlation between allergic reactions and tests with pooled venom.
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Four novel peptides were isolated from the venoms of the solitary eumenine wasps Eumenes rubrofemoratus and Eumenes fraterculus. Their sequences were determined by MALDI-TOF/TOF (matrix assisted laser desorption/ionization time-of-flight mass spectrometry) analysis, Edman degradation and solid-phase synthesis. Two of them, eumenitin-R (LNLKGLIKKVASLLN) and eumenitin-F (LNLKGLFKKVASLLT), are highly homologous to eumenitin, an antimicrobial peptide from a solitary eumenine wasp, whereas the other two, EMP-ER (FDIMGLIKKVAGAL-NH 2) and EMP-EF (FDVMGIIKKIAGAL-NH 2), are similar to eumenine mastoparan-AF (EMP-AF), a mast cell degranulating peptide from a solitary eumenine wasp. These sequences have the characteristic features of linear cationic cytolytic peptides; rich in hydrophobic and basic amino acids with no disulfide bond, and accordingly, they can be predicted to adopt an amphipathic α-helix secondary structure. In fact, the CD (circular dichroism) spectra of these peptides showed significant α-helical conformation content in the presence of TFE (trifluoroethanol), SDS (sodium dodecylsulfate) and asolectin vesicles. In the biological evaluation, all the peptides exhibited a significant broad-spectrum antimicrobial activity, and moderate mast cell degranulation and leishmanicidal activities, but showed virtually no hemolytic activity. © 2011 Elsevier Ltd.
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When searching for prospective novel peptides, it is difficult to determine the biological activity of a peptide based only on its sequence. The trial and error approach is generally laborious, expensive and time consuming due to the large number of different experimental setups required to cover a reasonable number of biological assays. To simulate a virtual model for Hymenoptera insects, 166 peptides were selected from the venoms and hemolymphs of wasps, bees and ants and applied to a mathematical model of multivariate analysis, with nine different chemometric components: GRAVY, aliphaticity index, number of disulfide bonds, total residues, net charge, pI value, Boman index, percentage of alpha helix, and flexibility prediction. Principal component analysis (PCA) with non-linear iterative projections by alternating least-squares (NIPALS) algorithm was performed, without including any information about the biological activity of the peptides. This analysis permitted the grouping of peptides in a way that strongly correlated to the biological function of the peptides. Six different groupings were observed, which seemed to correspond to the following groups: chemotactic peptides, mastoparans, tachykinins, kinins, antibiotic peptides, and a group of long peptides with one or two disulfide bonds and with biological activities that are not yet clearly defined. The partial overlap between the mastoparans group and the chemotactic peptides, tachykinins, kinins and antibiotic peptides in the PCA score plot may be used to explain the frequent reports in the literature about the multifunctionality of some of these peptides. The mathematical model used in the present investigation can be used to predict the biological activities of novel peptides in this system, and it may also be easily applied to other biological systems. © 2011 Elsevier Inc.
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Acylpolyamines are low molecular mass toxins occurring exclusively in the venoms from solitary wasps and some groups of spiders. Their chemical structures have been elucidated using hyphenated techniques of mass spectrometry, such as LC-MS and MS/MS, or through direct analysis with different types of NMR analyses. The chemical structures of the acylpolyamine toxins from the venoms of Nephilinae orb-web spiders appear to be organized into four parts based on the combinatorial way that the chemical building blocks are bound to each other. An aromatic moiety (part I) is connected through a linker amino acid (part II) to a polyamine chain (part III), which in turn may be connected to an optional tail (part IV). The polyamine chains were classified into seven subtypes according to the different combinations of chemical building blocks. These polyamine chains, in turn, are connected to one of three chromophore moieties: a 2,4-dihydroxyphenyl acetyl group, a 4-hydroxyindolyl acetyl group, or an indolyl acetyl group. They may be connected through an asparagine residue or sometimes through the dipeptide ornithyl asparagine. Also, nine different types of backbone tails may be attached to the polyamine chains. These toxins are noncompetitive blockers of ionotropic glutamate receptors with neuroprotective action against the neuronal death and antiepileptic effect. Thus, compounds of this class of spider venom toxin seem to represent interesting molecular models for the development of novel neuropharmaceutical drugs. © 2012 Elsevier B.V. All rights reserved.
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Honey bee venom toxins trigger immunological, physiological, and neurological responses within victims. The high occurrence of bee attacks involving potentially fatal toxic and allergic reactions in humans and the prospect of developing novel pharmaceuticals make honey bee venom an attractive target for proteomic studies. Using label-free quantification, we compared the proteome and phosphoproteome of the venom of Africanized honeybees with that of two European subspecies, namely Apis mellifera ligustica and A. m. carnica. From the total of 51 proteins, 42 were common to all three subspecies. Remarkably, the toxins melittin and icarapin were phosphorylated. In all venoms, icarapin was phosphorylated at the 205Ser residue, which is located in close proximity to its known antigenic site. Melittin, the major toxin of honeybee venoms, was phosphorylated in all venoms at the 10Thr and 18Ser residues. 18Ser phosphorylated melittin-the major of its two phosphorylated forms-was less toxic compared to the native peptide. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)