Snake venom galactoside-binding lectins: a structural and functional overview

Snake venom galactoside-binding lectins (SVgalLs) comprise a class of toxins capable of recognizing and interacting with terminal galactoside residues of glycans. In the past 35 years, since the first report on the purification of thrombolectin from Bothrops atrox snake venom, several SVgalLs from Viperidae and Elapidae snake families have been described, as has progressive improvement in the investigation of structural/functional aspects of these lectins. Moreover, the advances of techniques applied in protein-carbohydrate recognition have provided important approaches in order to screen for possible biological targets. The present review describes the efforts over the past 35 years to elucidate SVgalLs, highlighting their structure and carbohydrate recognition function involved in envenomation pathophysiology and potential biomedical applications.

Avaliação do efeito da crotoxina em animais portadores de encefalomielite autoimune experimental, um modelo de animais de esclerose múltipla / Evaluation of crotoxin effect in the experimental autoimune encephalomyelitis, an animal model of multiple sclerosis

A esclerose múltipla é uma doença inflamatória crônica, de origem autoimune, que acarreta diversas alterações motoras, cognitivas e sensitivas. Dentre as alterações sensitivas, a dor é um dos graves problemas que afetam pessoas portadoras desta doença, interferindo com diversos aspectos da vida do paciente. É importante ressaltar que a esclerose múltipla não tem cura, sendo que a terapêutica se concentra nas ações que retardam a progressão da doença e promovem o alívio dos sintomas, melhorando a qualidade da vida do paciente...

Multiple sclerosis is a Central Nervous System Inflamatory demyelinating disease that has as primary symptomps losses of sensory, cognitive and motor functions. Among the sensory alternations, pain is one of the major concern, afecting various aspects of the patients lives...

Effects of Bothrops moojeni venom on Leishmania amazonensis promastigote forms

In the present work, the effect of Bothrops moojeni venom fractions on Leishmania promastigotes was evaluated. The snake venom was fractionated into five protein fractions (E1 to E5), by ion exclusion chromatography, that were used to treat Leishmania amazonensis and Leishmania braziliensis promastigote forms whereas the viability and nitric oxide production were evaluated. It was observed that E5 venom fraction strongly inhibited Leishmania amazonensis nitric oxide production, while in Leishmania braziliensis the nitric oxide production was enhanced in all doses. Bothrops moojeni crude venom reduced the viability of both parasites in a dose-dependent manner and a peptide of 64 kDa was apparently degraded. Bothrops moojeni E5 venom fraction only reduced the viability and nitric oxide production of Leishmania amazonensis and no protein degradation was observed. Thus, these results suggest that Bothrops moojeni E5 venom fraction may offer components with a promising antileishmanial therapeutic application.

Crotalus durissus terrificus venom as a source of antitumoral agents

The basic knowledge on neoplasms is increasing quickly; however, few advances have been achieved in clinical therapy against tumors. For this reason, the development of alternative drugs is relevant in the attempt to improve prognosis and to increase patients' survival. Snake venoms are natural sources of bioactive substances with therapeutic potential. The objective of this work was to identify and characterize the antitumoral effect of Crotalus durissus terrificus venom (CV) and its polypeptide, crotoxin, on benign and malignant tumors, respectively, pituitary adenoma and glioblastoma. The results demonstrated that CV possess a powerful antitumoral effect on benign (pituitary adenoma) and malignant (glioblastoma multiforme) tumors with IC50 values of 0.96 ± 0.11 µg/mL and 2.15 ± 0.2 µg/mL, respectively. This antitumoral effect is cell-cycle-specific and dependent on extracellular calcium, an important factor for crotoxin phospholipase A2 activity. The CV antitumoral effect can be ascribed, at least partially, to the polypeptide crotoxin that also induced brain tumor cell death. In spite of the known CV nephrotoxicity and neurotoxicity, acute treatment with its antitumoral dose established in vitro was not found to be toxic to the analyzed animals. These results indicate the biotechnological potential of CV as a source of pharmaceutical templates for cancer therapy.

Immune response and neutralization capacity of antibodies produced in young sheep immunized with Crotalus durissus terrificus native or Cobalt-60 irradiated venom / esposta imune e capacidade de neutralização de anticorpos produzidos em ovinos jovens imunizados com veneno de Crotalus durissus terrificus nativo e irradiado com Cobalto 60

The ELISA technique was used to evaluate and compare young ovine humoral immune response during crotalic antiserum production. Animals were clinically evaluated throughout this process, and the neutralizing capacity of antisera raised against natural (NV) and Cobalt-60 irradiated (IrV) venoms of Crotalus durissus terrificus (C.d.t.) was verified by means of in vitro challenges. Three groups of six animals each were used: G1 received NV; G2 was inoculated with IrV; and G3 was used as control. Animals received six immunizations during 84 days at 14-day intervals. ELISA of antibody profile showed significant difference (p<5%) between experimental groups (G1

A técnica de Elisa foi utilizada para avaliar e comparar a resposta imune humoral de ovinos jovens para a produção de soro anticrotálico. Durante o processo de soroprodução, foi realizada a avaliação clínica dos animais. A capacidade de neutralização do soro produzido a partir de veneno de serpente Crotalus durissus terrificus, nativo (VN) e irradiado (VIr) com Cobalto–60 foi verificada por meio de desafios in vitro. Um grupo de seis animais recebeu veneno nativo, o segundo grupo recebeu veneno irradiado e o terceiro grupo foi o controle. Os animais receberam seis imunizações durante 84 dias com intervalo de14 dias. Houve diferença significativa (p<5%) no teste de ELISA do perfil de anticorpos produzidos pelos grupos experimentais (VN

Clinical and hematological alterations in dogs during experimental envenomation with Crotalus durissus terrificus venom and treated with antiophidic serum

The present work aimed to evaluate the clinical and hematological aspects during experimental envenomation by Crotalus durissus terrificus in dogs treated with different antiophidic serum doses. Sixteen dogs were divided into two groups of eight animals each. Group I received 1mg/kg venom subcutaneously and 30mg antiophidic serum intravenously; Group II received 1mg/kg venom subcutaneously and 60mg antiophidic serum intravenously. In the clinical evaluation, we observed ataxia, moderate sedation, dilated pupils, sialorrhea, flaccid paralysis of mandibular muscles, and discreet edema at the site of venom inoculation. Evaluating red and white blood cells, we observed a decrease of hemoglobins, globular volume and erythrocytes, and an increase of plasmatic proteins, leukocytes, neutrophils, monocytes and lymphocytes. Clotting time increased and there was blood incoagulability with return to normal clotting time six hours after antiophidic serum administration. Animals treated with six antiophidic serum flasks had a faster recovery than the animals that received three serum flasks

Experimental use of fibrin glue derived from snake venom in non-pregnant canine uterus

This study evaluated the use of fibrin glue derived from snake venom in the healing process after canine histerorrhaphy. Three groups of four animals were submitted to uterine hysterotomy followed by wound closure. In Group 1, double-layer suture was used, the first with Schimieden pattern, the second with Cushing pattern; in Group 2, only fibrin glue; and in Group 3, the same as for Group 1 but with fibrin glue as suture reinforcement. Results indicated that fibrin glue produced less inflammation in the exudative phase, and exacerbated deposition of connective tissue and angiogenesis in the proliferative and maturation phases of the healing process, favoring its evolution.

Veneno do bem / The good poison

Cinco anos após ter sido utilizada pioneiramente em humanos, a cola de fibrina, um adesivo biológico feito a partir do veneno da cascavel e fibrinogênio, é experimentada pela primeira vez na Odontologia brasileira. O material foi objeto de estudo da tese de doutorado em Periodontia defendida em setembro último na Faculdade de odontologia de Bauru da Universidade de São Paulo (FOB/USP) por Mônica Dourado Barbosa de Oliveira, de Salvador (BA), sob orientação do professor Sebastião Greghi

Heparin-antivenom association: differential neutralization effectiveness in Bothrops atrox and Bothrops erythromelas envenoming

Heparin, in some regions of Brazil has been used in the treatment of bothropic accidents, but the data found in the literature are inconclusive about its effectiveness. The venoms of Bothrops atrox and of B. erythromelas were characterized according to their biological activities. The capacity of heparin in neutralizing these activities was tested with doses of 3 and 6 IU in isolated form and associated to Antibothropic Serum (ABS). It was verified that heparin, in doses of 3 and 6 IU, was not effective in neutralizing the desfibrinating and edema-forming activities of B. atrox venom and the hemorrhagic and coagulant actions of both venoms. Heparin diminished the effectiveness of the ABS in the neutralization of the hemorrhagic and edema-forming activities of the B. atrox venom. However, heparin in the 6 IU dose was capable of neutralize the edema-forming of the B. erythromelas and increase the effectiveness of the ABS. Heparin also neutralized the phospholipasic A2 activity of B. atrox (14.3 percent) and B. erythromelas (28.0 percent) venoms. For B. erythromelas venom, the associated treatment, heparin and ABS, was more effective in the neutralization of its lethal activity

Antitumor effect of snake venoms

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 Bothrops 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.