RESUMEN

Os acidentes por animais peçonhentos, especialmente os acidentes ofídicos, foram incluídos pela Organização Mundial da Saúde (OMS) na lista das doenças tropicais negligenciadas que acometem, na maioria das vezes, populações pobres que vivem em áreas rurais, devido à gravidade constituem um problema de saúde pública. O sucesso no tratamento do paciente para que os mesmos não gerem sequelas graves, podendo chegar ao óbito, requer atendimento de forma rápida, com o uso adequado do soro específico quando necessário para cada espécie de serpentes e na quantidade recomendada. Em Goiás as principais serpentes que causam acidente são dos gêneros: Bothrops (jararacas), Crotalus (cascavéis) e Micrurus (coral), são considerados acidentes graves que demandam o uso de soros antivenenos específicos

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Accidents by venomous animals, especially snakebites, were included by the World Health Organization (WHO) in the list of neglected tropical diseases that affect, most of the time, poor people living in rural areas, due to the seriousness of a public health problem. . Successful treatment of the patient so that they do not generate serious sequelae, which can lead to death, requires quick care, with the appropriate use of specific serum when necessary for each species of snakes and in the recommended amount. In Goiás, the main snakes that cause accidents are of the genera: Bothrops (jararacas), Crotalus (rattlesnakes) and Micrurus (coral), are considered serious accidents that require the use of specific antivenom serums

Asunto(s)

Humanos , Masculino , Femenino , Mordeduras de Serpientes/clasificación , Mordeduras de Serpientes/epidemiología , Mordeduras de Serpientes/complicaciones , Mordeduras de Serpientes/diagnóstico , Mordeduras de Serpientes/terapia , Venenos de Crotálidos/clasificación

RESUMEN

Venom is a key adaptive innovation in snakes, and how nonvenom genes were co-opted to become part of the toxin arsenal is a significant evolutionary question. While this process has been investigated through the phylogenetic reconstruction of toxin sequences, evidence provided by the genomic context of toxin genes remains less explored. To investigate the process of toxin recruitment, we sequenced the genome of Bothrops jararaca, a clinically relevant pitviper. In addition to producing a road map with canonical structures of genes encoding 12 toxin families, we inferred most of the ancestral genes for their loci. We found evidence that 1) snake venom metalloproteinases (SVMPs) and phospholipases A2 (PLA2) have expanded in genomic proximity to their nonvenomous ancestors; 2) serine proteinases arose by co-opting a local gene that also gave rise to lizard gilatoxins and then expanded; 3) the bradykinin-potentiating peptides originated from a C-type natriuretic peptide gene backbone; and 4) VEGF-F was co-opted from a PGF-like gene and not from VEGF-A. We evaluated two scenarios for the original recruitment of nontoxin genes for snake venom: 1) in locus ancestral gene duplication and 2) in locus ancestral gene direct co-option. The first explains the origins of two important toxins (SVMP and PLA2), while the second explains the emergence of a greater number of venom components. Overall, our results support the idea of a locally assembled venom arsenal in which the most clinically relevant toxin families expanded through posterior gene duplications, regardless of whether they originated by duplication or gene co-option.

Asunto(s)

Bothrops/genética , Venenos de Crotálidos/genética , Evolución Molecular , Genoma/genética , Venenos de Serpiente/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bothrops/clasificación , Venenos de Crotálidos/clasificación , Femenino , Perfilación de la Expresión Génica/métodos , Filogenia , Proteoma/metabolismo , Proteómica/métodos , RNA-Seq/métodos , Análisis de Secuencia de ADN/métodos , Venenos de Serpiente/clasificación

RESUMEN

Adult rattlesnakes within genus Crotalus express one of two distinct venom phenotypes, type I (hemorrhagic) and type II (neurotoxic). In Costa Rican Central American rattlesnake, ontogenetic changes in the concentration of miRNAs modulate venom type II to type I transition. Venomics and venom gland transcriptome analyses showed that adult C. simus and C. tzabcan expressed intermediate patterns between type II and type I venoms, whereas C. culminatus had a canonical type I venom. Neonate/juvenile and adult Mexican rattlesnakes showed notable inter- and intraspecific variability in the number, type, abundance and ontogenetic shifts of the transcriptional and translational venom gland activities. These results support a role for miRNAs in the ontogenetic venom compositional changes in the three congeneric Mexican rattlesnakes. It is worth noting the finding of dual-action miRNAs, which silence the translation of neurotoxic heterodimeric PLA2 crotoxin and acidic PLA2 mRNAs while simultaneously up-regulating SVMP-targeting mRNAs. Dual transcriptional regulation potentially explains the existence of mutually exclusive crotoxin-rich (type-II) and SVMP-rich (type-I) venom phenotypic dichotomy among rattlesnakes. Our results support the hypothesis that alterations of the distribution of miRNAs, modulating the translational activity of venom gland toxin-encoding mRNAs in response to an external cue, may contribute to the mechanism generating adaptive venom variability.

Asunto(s)

Venenos de Crotálidos/genética , Crotalus/genética , MicroARNs/genética , Proteogenómica/métodos , Proteoma/genética , Transcriptoma , Factores de Edad , Animales , Secuencia de Bases , Cromatografía de Fase Inversa/métodos , Venenos de Crotálidos/biosíntesis , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/aislamiento & purificación , Crotalus/crecimiento & desarrollo , Crotalus/metabolismo , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Ontología de Genes , Variación Genética , MicroARNs/metabolismo , Anotación de Secuencia Molecular , Biosíntesis de Proteínas , Proteogenómica/instrumentación , Proteoma/metabolismo , Especificidad de la Especie

RESUMEN

Within the Neotropical pit vipers, a lineage of primarily Middle American snake species referred to as the "Porthidium group" includes the genera Atropoides, Cerrophidion, and Porthidium. In this study, the venom proteomes of Porthidium nasutum, P. ophryomegas, and Cerrophidion godmani from Costa Rica were analyzed, and correlated to their toxic and enzymatic activities. Their HPLC profiles revealed a higher similarity between the two Porthidium species than between these and C. godmani. Proteins belonging to nine (P. nasutum), eight (P. ophryomegas), and nine (C. godmani) families were identified by mass spectrometry or N-terminal sequencing. Final cataloging of proteins and their relative abundances confirmed the close relationship between venoms of P. nasutum and P. ophryomegas, departing from that of C. godmani. Since the latter species had been taxonomically classified as Porthidium godmani previously, our venomic analyses agree with its current generic status. Venoms of P. nasutum and P. ophryomegas, despite containing abundant metalloproteinases and serine proteinases, lack procoagulant activity on human plasma, in contrast to venom of C. godmani. The latter induced strong myotoxicity in mice, which correlates with its high proportion of phospholipases A(2), whereas venoms from the two Porthidium species, containing lower amounts of these enzymes, induced only mild muscle damage.

Asunto(s)

Venenos de Crotálidos/metabolismo , Viperidae/metabolismo , Animales , Cromatografía Líquida de Alta Presión , Costa Rica , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/toxicidad , Humanos , Espectrometría de Masas , Ratones , Especificidad de la Especie , Viperidae/clasificación

RESUMEN

The genus Bothrops spp. is responsible for 90% of envenomation by snakes in Brazil, and the standard treatment for snakebites is the antivenom therapy. The anti-bothropic serum produced by Butantan Institute is prepared by the hyperimmunization of horses with a pool of venoms from Bothrops alternatus, Bothrops jararaca, Bothrops jararacussu, Bothrops moojeni and Bothrops neuwiedi. In this study, the biochemical and biological characteristics of the venoms from nineteen snakes of the genus Bothrops, responsible for human accidents in Brazil, were analysed. Venoms, particularly from Crotalidae and Viperidae snakes, are rich sources of serine proteases and metalloproteases and the ability of the Brazilian anti-bothropic serum to neutralize the proteolytic activity of these venoms were also tested. The results obtained here show the existence of a large range of variation in the composition and activities in Bothrops spp. toxins and demonstrate that the anti-bothropic serum is not able to fully neutralize the toxic activities of all analysed venoms. These suggest that for the preparation of a fully effective therapeutic anti-bothropic serum, other venoms should be included in the immunization mixture.

Asunto(s)

Bothrops , Venenos de Crotálidos/química , Venenos de Crotálidos/toxicidad , Animales , Antivenenos/inmunología , Brasil , Reacciones Cruzadas , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/inmunología , Caballos , Hialuronoglucosaminidasa/metabolismo , Dosificación Letal Mediana , Masculino , Ratones , Pruebas de Neutralización , Péptido Hidrolasas/metabolismo , Fosfolipasas A2/metabolismo , Especificidad de la Especie

RESUMEN

Bothropasin is a 48kDa hemorrhagic PIII snake venom metalloprotease (SVMP) isolated from Bothrops jararaca, containing disintegrin/cysteine-rich adhesive domains. Here we present the crystal structure of bothropasin complexed with the inhibitor POL647. The catalytic domain consists of a scaffold of two subdomains organized similarly to those described for other SVMPs, including the zinc and calcium-binding sites. The free cysteine residue Cys189 is located within a hydrophobic core and it is not available for disulfide bonding or other interactions. There is no identifiable secondary structure for the disintegrin domain, but instead it is composed mostly of loops stabilized by seven disulfide bonds and by two calcium ions. The ECD region is in a loop and is structurally related to the RGD region of RGD disintegrins, which are derived from PII SVMPs. The ECD motif is stabilized by the Cys277-Cys310 disulfide bond (between the disintegrin and cysteine-rich domains) and by one calcium ion. The side chain of Glu276 of the ECD motif is exposed to solvent and free to make interactions. In bothropasin, the HVR (hyper-variable region) described for other PIII SVMPs in the cysteine-rich domain, presents a well-conserved sequence with respect to several other PIII members from different species. We propose that this subset be referred to as PIII-HCR (highly conserved region) SVMPs. The differences in the disintegrin-like, cysteine-rich or disintegrin-like cysteine-rich domains may be involved in selecting target binding, which in turn could generate substrate diversity or specificity for the catalytic domain.

Asunto(s)

Venenos de Crotálidos/química , Metaloendopeptidasas/química , Secuencia de Aminoácidos , Sitios de Unión , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/aislamiento & purificación , Cristalografía por Rayos X , Cisteína/química , Desintegrinas/química , Metaloendopeptidasas/clasificación , Metaloendopeptidasas/aislamiento & purificación , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Alineación de Secuencia , Análisis de Secuencia de Proteína

RESUMEN

Snake venom metalloproteases (SVMPs) embody zinc-dependent multidomain enzymes responsible for a relevant pathophysiology in envenomation, including local and systemic hemorrhage. The molecular features responsible for hemorrhagic potency of SVMPs have been associated with their multidomains structures which can target these proteins them to several receptors of different tissues and cellular types. BjussuMP-I, a SVMP isolated from the Bothrops jararacussu venom, has been characterized as a P-III hemorrhagic metalloprotease. The complete cDNA sequence of BjussuMP-I with 1641bp encodes open reading frames of 547 amino acid residues, which conserve the common domains of P-III high molecular weight hemorrhagic metalloproteases: (i) pre-pro-peptide, (ii) metalloprotease, (iii) disintegrin-like and (iv) rich cysteine domain. BjussuMP-I induced lyses in fibrin clots and inhibited collagen- and ADP-induced platelet aggregation. We are reporting, for the first time, the primary structure of an RGD-P-III class snake venom metalloprotease. A phylogenetic analysis of the BjussuMP-I metalloprotease/catalytic domain was performed to get new insights into the molecular evolution of the metalloproteases. A theoretical molecular model of this domain was built through folding recognition (threading) techniques and refined by molecular dynamics simulation. Then, the final BjussuMP-I catalytic domain model was compared to other SVMPs and Reprolysin family proteins in order to identify eventual structural differences, which could help to understand the biochemical activities of these enzymes. The presence of large hydrophobic areas and some conserved surface charge-positive residues were identified as important features of the SVMPs and other metalloproteases.

Asunto(s)

Bothrops/genética , Bothrops/metabolismo , Venenos de Crotálidos/química , Venenos de Crotálidos/genética , Metaloendopeptidasas/química , Metaloendopeptidasas/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Bothrops/clasificación , Dominio Catalítico/genética , Simulación por Computador , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/toxicidad , ADN Complementario/genética , Fibrinólisis/efectos de los fármacos , Técnicas In Vitro , Metaloendopeptidasas/clasificación , Metaloendopeptidasas/toxicidad , Modelos Moleculares , Datos de Secuencia Molecular , Filogenia , Agregación Plaquetaria/efectos de los fármacos , Conejos , Homología de Secuencia de Aminoácido , Electricidad Estática , Termodinámica

RESUMEN

Efforts to describe toxins from the two major families of venomous snakes (Viperidae and Elapidae) usually reveal proteins belonging to few structural types, particular of each family. Here we carried on an effort to determine uncommon cDNAs that represent possible new toxins from Lachesis muta (Viperidae). In addition to nine classes of typical toxins, atypical molecules never observed in the hundreds of Viperidae snakes studied so far are highly expressed: a diverging C-type lectin that is related to Viperidae toxins but appears to be independently originated; an ohanin-like toxin, which would be the third member of the most recently described class of Elapidae toxins, related to human butyrophilin and B30.2 proteins; and a 3FTx-like toxin, a new member of the widely studied three-finger family of proteins, which includes major Elapidae neurotoxins and CD59 antigen. The presence of these common and uncommon molecules suggests that the repertoire of toxins could be more conserved between families than has been considered, and their features indicate a dynamic process of venom evolution through molecular mechanisms, such as multiple recruitments of important scaffolds and domain exchange between paralogs, always keeping a minimalist nature in most toxin structures in opposition to their nontoxin counterparts.

Asunto(s)

Venenos de Crotálidos/química , Venenos de Crotálidos/genética , ADN Complementario/genética , Venenos Elapídicos/química , Venenos Elapídicos/genética , Elapidae/genética , Evolución Molecular , Viperidae/genética , Secuencia de Aminoácidos , Animales , Venenos de Crotálidos/clasificación , Venenos Elapídicos/clasificación , Elapidae/clasificación , Etiquetas de Secuencia Expresada , Datos de Secuencia Molecular , Familia de Multigenes , Filogenia , Estructura Terciaria de Proteína , Homología de Secuencia de Aminoácido , Especificidad de la Especie , Viperidae/clasificación

RESUMEN

Snake venom (sv) C-type lectins encompass a group of hemorrhagic toxins, which are able to interfere with hemostasis. They share significant similarity in their primary structures with C-type lectins of other animals, and also present a conserved carbohydrate recognition domain (CRD). A very well studied sv C-type lectin is the heterodimeric toxin, convulxin (CVX), from the venoms of South American rattlesnakes, Crotalus durissus terrificus and C. d. cascavella. It consists of two subunits, alfa (CVXa, 13.9 kDa) and beta (CVXb, 12.6 kDa), joined by inter and intra-chain disulfide bounds, and is arranged in a tetrameric a4b4 conformation. Convulxin is able to activate platelet and induce their aggregation by acting via p62/GPVI collagen receptor. Several cDNA precursors, homolog of CVX subunits, were cloned by PCR homology screening. As determined by computational analysis, one of them, named crotacetin b subunit, was predicted as a polypeptide with a tridimensional conformation very similar to other subunits of convulxin-like snake toxins. Crotacetin was purified from C. durissus venoms by gel permeation and reverse phase high performance liquid chromatography. The heterodimeric crotacetin is expressed in the venoms of several C. durissus subspecies, but it is prevalent in the venom of C. durissus cascavella. As inferred from homology modeling, crotacetin induces platelet aggregation but noticeably exhibits antimicrobial activity against Gram-positive and Gram-negative bacteria

Asunto(s)

Animales , Crotalus , Fosfatidilcolinas/aislamiento & purificación , Homología de Secuencia de Aminoácido , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/química , Alineación de Secuencia

RESUMEN

Components with phospholipase A2 activity were isolated by gel filtration and cationic exchange chromatography from the venom of Bothrops asper snakes from Chiriguaná, Colombia (9°22´N; 73°37´W). Five fractions were obtained by the gel filtration, and PLA2 activity was found in fraction 3 (F3). In the cationic exchange chromatography, F3 showed eight components with PLA2 activity. Six of these components appeared as one band in polyacrylamide gel electrophoresis (SDS-PAGE). Fractions II and VII exhibited an optimal activity at pH 9 and 52ºC. The optimum calcium concentration for fraction II was 48 mM and for fraction VII, 384 mM. Both fractions showed thermal stability. Fraction II was stable at pH values between 2.5 and 9, and fraction VII, between 2.5 and 8. The Michaelis Menten constant (K M) was 3.5x10-3 M for fraction II and 1.6x10-3 M for fraction VII. The molecular weight was 16,000 Dalton for fraction II and 17,000 Dalton for fraction VII. Both isoenzymes did not show any toxic activity (DL50) at 5.3 and 4 µg/g. The two fractions showed different kinetic constant (K M), calcium requirement, and substrate specificity for haemolytic activity.

Asunto(s)

Animales , Masculino , Ratones , Fosfolipasas A , Venenos de Crotálidos/clasificación , Venenos de Crotálidos/aislamiento & purificación , Colombia

RESUMEN

In 1984, the first venom phospholipase A2 (PLA2) with a lysine substituting for the highly conserved aspartate 49 was discovered, in the North American crotalid snake Agkistrodon p. piscivorus [J. Biol. Chem. 259 (1984) 13839]. Ten years later, the first mapping of a 'toxic region' on a Lys49 PLA2 was reported, in Bothrops asper myotoxin II [J. Biol. Chem. 269 (1994) 29867]. After a further decade of research on the Lys49 PLA2s, a better understanding of their structural determinants of toxicity and mode of action is rapidly emerging, with myotoxic effector sites identified at the C-terminal region in at least four proteins: B. asper myotoxin II, A. p. piscivorus K49 PLA2, A. c. laticinctus ACL myotoxin, and B. jararacussu bothropstoxin I. Although important features still remain to be established, their toxic mode of action has now been understood in its more general concepts, and a consistent working hypothesis can be experimentally supported. It is proposed that all the toxic activities of Lys49 PLA2s are related to their ability to destabilize natural (eukaryotic and prokaryotic) and artificial membranes, using a cationic/hydrophobic effector site located at their C-terminal loop. This review summarizes the general properties of the Lys49 PLA2 myotoxins, emphasizing the development of current concepts and hypotheses concerning the molecular basis of their toxic activities.

Asunto(s)

Bothrops/genética , Venenos de Crotálidos/toxicidad , Membranas/efectos de los fármacos , Mutación Missense/genética , Fosfolipasas A/química , Secuencia de Aminoácidos , Animales , Sitios de Unión , Bothrops/metabolismo , Venenos de Crotálidos/química , Venenos de Crotálidos/clasificación , Datos de Secuencia Molecular , Músculos/metabolismo , Fosfolipasas A/genética , Fosfolipasas A2 , Conformación Proteica

RESUMEN

A comparative study was performed on the venoms of adult specimens of the neotropical rattlesnake, Crotalus durissus, from Guatemala, Costa Rica, Venezuela and Brazil, together with the venom of newborn specimens of C. d. durissus from Costa Rica. Venoms from Brazil (C. d. terrificus) and from newborn specimens of C. d. durissus presented an electrophoretic pattern characterized by the predominance of bands with molecular mass of 36 and 15 kDa, whereas those of adult specimens of C. d. durissus from Guatemala and Costa Rica, and C. d. cumanensis from Venezuela, showed a conspicuous band of 62 kDa, and additional bands of 36, 29 and 15 kDa. Moreover, venoms from C. d. terrificus and C. d. cumanensis showed a prominent band of < 10 kDa that probably corresponds to crotamine, since a 'crotamine-like' activity was detected in these venoms upon intraperitoneal injection in mice. Venoms of C. d. terrificus, C. d cumanensis and newborn C. d. durissus induced higher lethal and myotoxic effects than those of adult C. d. durissus. In contrast, adult C. d. durissus and C. d. cumanensis venoms induced hemorrhage, whereas venoms of C. d. terrificus and newborn C. d. durissus lacked this effect. All venoms showed coagulant effect in plasma, the highest activity being observed in the venom of newborn C. d. durissus. An anti-crotalic antivenom produced by Instituto Butantan (Brazil), using C. d. terrificus venom as antigen, was effective in the neutralization of lethal, myotoxic and coagulant effects of all venoms studied, being ineffective in the neutralization of hemorrhagic activity of the venoms of C. d. cumanensis and C. d. durissus. On the other hand, a polyvalent antivenom produced by Instituto Clodomiro Picado (Costa Rica), using the venoms of C. d. durissus. Bothrops asper and Lachesis stenophrys as antigens, was able to neutralize lethal, myotoxic, coagulant and hemorrhagic effects of C. d. durissus venom, but was ineffective in the neutralization of lethality and myotoxicity of C. d. terrificus, C. d. cumanensis and newborn C. d. durissus venom. The high toxicity of South American and newborn C. d. durissus venoms is related to the presence of high concentrations of the neurotoxic phospholipase A2 complex 'crotoxin'. Accordingly, antivenom from Instituto Butantan has a much higher titer of anti-crotoxin antibodies than antivenom from Instituto Clodomiro Picado. Crotalus durissus represents an example of intraspecies variation in venom composition and pharmacology that has relevant pathophysiologic and therapeutic implications.

Asunto(s)

Venenos de Crotálidos/clasificación , Crotalus , Animales , Brasil , Costa Rica , Venenos de Crotálidos/farmacología , Electroforesis en Gel de Poliacrilamida , Guatemala , Ratones , Venezuela

RESUMEN

A survey is made of the taxonomic literature on South American rattlesnakes (genus Crotalus, family Viperidae). Two main areas are emphasized: the attribution of the names proposed in the eighteenth century by Linnaeus and Laurenti, and the current scheme of division in subspecies. The attribution of names is examined based on the original descriptions and on relevant previous and contemporary literature. The presently adopted scheme, proposed by Klauber (1941, 1972) is found not entirely satisfactory, but reasonable enough--besides being hallowed by use. The scheme of geographical differentiation, intrinsically important and with broad practical implications (differentiation of the venom) is found to be the culmination of a long series of deficient analyses, and in urgent need of proper investigation.

Asunto(s)

Crotalus/clasificación , Animales , Venenos de Crotálidos/clasificación , América del Sur

RESUMEN

A comparative study was performed on the venoms of adult specimens of the neotropical rattlesnake, Crotalus durissus, from Guatemala, Costa Rica, Venezuela and Brazil, together with the venom of newborn specimens of C. d. durissus from Costa Rica. Venoms from Brazil (C. d. terrificus) and from newborn specimens of C. d. durissus presented an electrophoretic pattern characterized by the predominance of bands with molecular mass of 36 and 15 kDa, whereas those of adult specimens of C. d. durissus from Guatemala and Costa Rica, and C. d. cumanensis from Venezuela, showed a conspicuous band of 62 kDa, and additional bands of 36, 29 and 15 kDa. Moreover, venoms from C. d. terrificus and C. d. cumanensis showed a prominent band of < 10 kDa that probably corresponds to crotamine, since a 'crotamine-like' activity was detected in these venoms upon intraperitoneal injection in mice. Venoms of C. d. terrificus, C. d cumanensis and newborn C. d. durissus induced higher lethal and myotoxic effects than those of adult C. d. durissus. In contrast, adult C. d. durissus and C. d. cumanensis venoms induced hemorrhage, whereas venoms of C. d. terrificus and newborn C. d. durissus lacked this effect. All venoms showed coagulant effect in plasma, the highest activity being observed in the venom of newborn C. d. durissus. An anti-crotalic antivenom produced by Instituto Butantan (Brazil), using C. d. terrificus venom as antigen, was effective in the neutralization of lethal, myotoxic and coagulant effects of all venoms studied, being ineffective in the neutralization of hemorrhagic activity of the venoms of C. d. cumanensis and C. d. durissus. On the other hand, a polyvalent antivenom produced by Instituto Clodomiro Picado (Costa Rica), using the venoms of C. d. durissus. Bothrops asper and Lachesis stenophrys as antigens, was able to neutralize lethal, myotoxic, coagulant and hemorrhagic effects of C. d. durissus venom, but was ineffective in the neutralization of lethality and myotoxicity of C. d. terrificus, C. d. cumanensis and newborn C. d. durissus venom. The high toxicity of South American and newborn C. d. durissus venoms is related to the presence of high concentrations of the neurotoxic phospholipase A2 complex 'crotoxin'. Accordingly, antivenom from Instituto Butantan has a much higher titer of anti-crotoxin antibodies than antivenom from Instituto Clodomiro Picado. Crotalus durissus represents an example of intraspecies variation in venom composition and pharm

Asunto(s)

Animales , Ratones , Crotalus , Venenos de Crotálidos/clasificación , Brasil , Costa Rica , Electroforesis en Gel de Poliacrilamida , Guatemala , Venenos de Crotálidos/farmacología , Venezuela