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PubMed2003

Immunohistochemical changes in kidney glomerular and tubular proteins caused by rattlesnake (Crotalus vegrandis) venom.

Renal damage is an important cause of death in patients who have survived the early effects of severe crotalid envenomation. Extracellular matrix of renal tissue is altered by Crotalus toxin activities. The aim of this study was to describe how cytoskeletal proteins and basal membrane components undergo substantial alterations under the action of Crotalus vegrandis crude venom and its hemorrhagic fraction (Uracoina-1) in mice. To detect the proteins in question, the immunoperoxidase method with monoclonal and polyclonal antibodies was used. Cell types within renal lesions were characterized by phenotypic identification, by means of immunohistologic analysis of marker proteins using different primary antibodies against mesangial cells, endothelial cells, cytoskeletal proteins (intermediate filament), extracellular matrix and basal membranes. Samples for morphological study by standard procedures (biotin-streptavidin-peroxidase technique) using light microscopy were processed. Positive and negative controls for each antigen tested in the staining assay were included. After crude venom and hemorrhagic fraction inoculation of mice, the disappearance of cytoskeletal vimentin and desmin and collagen proteins in the kidney was observed. In extracellular matrix and basal membranes, collagen type IV from envenomed animals tends to disappear from 24 h to 120 h after venom injection.

Animals↗
PubMed1991

The hypotensive activity of Crotalus atrox (western diamondback rattlesnake) venom: identification of its origin.

Viperidae snakes belonging to the genus Crotalus, subfamily Crotalinae, include the species durissus terrificus, durissus durissus, adamanteus, atrox, cerastes, horridus, molossus, scutulatus, viridis and others. All of them, except for the first 2, are found in North America. Crotalus atrox, or diamondback rattlesnakes, live in the southwest United States and in Mexico. This paper describes the fractionation of C. atrox venom in order to isolate and identify its hypotensive agents.

Amino Acid Sequence↗
PubMed1999

Ultrastructural pathology in skeletal muscle of mice envenomed with Crotalus vegrandis venom.

In this ultrastructural study we examined skeletal muscle fibres from mice intraperitoneally inoculated with a sublethal dose of Crotalus vegrandis (rattlesnake) venom. The group of mice inoculated presented neurological symptoms characterised by respiratory failure and hind limbs paralysis. Skeletal muscle fibres showed different degrees of alterations. Most of them presented the characteristic pattern of necrosis in progress. Atrophied and hypercontracted fibres were frequently seen. Some atrophied and necrotic fibres showed several nucleoli-like bodies in the nucleus. In the atrophic and hypercontracted fibres, sarcoplasmic vacuolation and abnormal mitochondria with stacked cristae were observed. Areas of segmental necrosis were also frequently found. In connection with these altered muscle fibres, capillary abnormalities were detected. This study suggests that in envenomed mice respiratory failure symptoms may be related with muscle damage caused by Crotalus vegrandis venom components.

Animals↗
PubMed1988

Studies on the mechanism of hemorrhage production by five proteolytic hemorrhagic toxins from Crotalus atrox venom.

The sites and relative rates of peptide bond hydrolysis of the oxidized B chain of bovine insulin by two hemorrhagic proteinases, Ht-a and Ht-b, isolated from the venom of the Western Diamondback Rattlesnake, Crotalus atrox, were investigated. The results were compared with previous results on the digestion of the same substrate by the C. atrox hemorrhagic proteinases Ht-c, d, and e. Both toxins, Ht-a and Ht-b, were found to cleave the His5-Leu6, His10-Leu11, Ala14-Leu15, and Tyr16-Leu17 bonds of the oxidized insulin B chain. In addition, Ht-a cleaves the Asn3-Gln4 bond, whereas Ht-b cleaves the Gly23-Phe24 bond. The cleavage specificity of Ht-b on the insulin B chain is identical to that of the weakly hemorrhagic isoenzymes Ht-c and Ht-d. Hemorrhagic proteinase Ht-a cleaves the Ala14-Leu15 bond most rapidly, having a turnover number of 12.6 min-1 which was approximately twice as fast as the Tyr16-Leu17 bond turnover of cleavage. Hemorrhagic proteinase Ht-b, on the other hand, cleaves the Tyr16-Leu17 bond fastest, having a turnover number of 61.3 min-1. The Ala14-Leu15 bond is the peptide bond cleaved the second fastest by Ht-b, with a turnover number of 48.2 min-1. The five hemorrhagic toxins from Crotalus atrox venom were also examined for their capability to hydrolyse basement membrane preparations, and the identities of the digested proteins comprising the basement membrane were determined. From the results it is concluded that all five hemorrhagic toxins cleave laminin and the component of the basement membrane referred to as band a.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1978

[Early effect of Crotalus durissus terrificus venom on kidney circulation].

Local blood flow was measured in renal cortex (1 mm below cortical surface) by means of the hydrogen clearance method in urethanized rats. Recording of blood pressure from femoral artery was performed. Crotalus durissus terrificus venom injection (one mg/kg i.v.) significantly decreased cortical blood flow at 10 min, without a significant arterial pressure modification. Posterior injection of mannitol 200 mg induced a significant increase in cortical blood flow, although initial values were not reached. Electron microscopy showed thromboses in the glomerular capillaries 35 minutes after venom injection. It is suggested that the precocious effect of this venom on renal cortical blood flow may be instrumental in the development of the renal acute insufficiency induced by Crotalus durissus terrificus venom.

Animals↗
PubMed1983

Kallikrein-like enzymes from Crotalus atrox venom.

The symptoms which immediately follow envenomation by many crotalid snakes include hypotension, hypovolemia, hemoconcentration, and shock. We have isolated and characterized two proteases (EI and EII) from the venom of Crotalus atrox which may be involved in the onset of these symptoms. EI and EII have molecular weights of 27,500 and 29,200 and isoelectric points of 4.7 and 4.3, respectively. Specific esterolytic activities of EI and EII on N alpha-p-tosyl-L-arginine methyl ester are 51.5 mumol min-1mg-1 and 48.1 mumol min-1 mg-1, respectively. Both enzymes are rather specific in their substrate requirements in that neither was demonstrated to have any proteolytic activity against either of the oxidized chains of insulin, or glucagon. Neither enzyme was shown to have plasmin or fibrinolytic activity. Both enzymes are able to cleave a kininogen analog to release bradykinin. This proteolytic activity is inhibited by aprotinin and phenylmethanesulfonyl fluoride but not by ethylenediaminetetraacetate. The enzymes are active upon the kallikrein substrates S2666 and S2302. The Km values of the enzymes with these substrates are similar to those reported for kallikrein. Structural similarity between the two enzymes was demonstrated by ultraviolet and circular dichroic spectroscopy, and amino acid analysis. Tryptic peptide mapping of the two native enzymes also suggested a large degree of structural similarity. Furthermore, sequence studies on the NH2-terminal regions of the enzymes indicate that they share a significant degree of sequence homology with porcine kallikrein and crotalase, a kallikrein-like enzyme from Crotalus adamanteus. The main physical difference between the two kallikreins reported here appears to be due to the carbohydrate moieties on the enzymes. At present the in vivo role of venom kallikreins in envenomation pathology is uncertain; however, it is possible that they play an important part in giving rise to the initial symptoms of hypotension and shock.

Amino Acid Sequence↗
PubMed1984

Fibrinogenolytic afibrinogenemia after envenomation by western diamondback rattlesnake (Crotalus atrox).

The absence of fibrinogen and the presence of plasmic fragments X, Y, D, and E were demonstrated in a patient bitten by a western diamondback rattlesnake, Crotalus atrox. The factor VIII level and the platelet count were within normal limits. There were distinct changes of protease inhibitors in the patient's plasma. Alpha-1-protease inhibitor was elevated. Antithrombin-III was only slightly decreased after the envenomation, but alpha 2-antiplasmin and alpha 2-macroglobulin were initially significantly lowered, returning to normal values in 38 and 3 days, respectively. Plasmin-alpha 2-antiplasmin complex was present until day 10 after the envenomation. However, purified plasminogen was not activated in vitro by the venom. Cultured endothelial and smooth muscle cells from human blood vessels released an increased amount of plasminogen activator upon incubation with the venom. The release did not result from cell lysis. Platelets in normal human platelet-rich plasma were aggregated by 10 micrograms/ml of the venom, without serotonin secretion. The aggregation kinetics and serotonin secretion induced by adenosine diphosphate (ADP) or arachidonate were not significantly affected by the venom at 1-10 micrograms/ml. It is concluded that the predominant mechanism of afibrinogenemia in the patient after Crotalus atrox bite resulted from primary fibrinogenolysis and not from a consumptive coagulopathy. The lytic state seemed to be induced through an indirect activation of plasminogen by vascular plasminogen activator, which was probably released from endothelial cells and smooth muscle cells by the snake venom.

Adult↗
PubMed1995

Neutralization of the effect of Crotalus durissus terrificus venom by gangliosides.

We determined the ability of a mixture of gangliosides (16% GD1b, 19% GT1b, 21% GM1, 40% GD1a) to neutralize the effect of Crotalus durissus terrificus (Cdt) venom in vitro and in vivo. Protection was indicated by the absence of muscular contractions, hind limb paralysis or death of BALB/c mice (16-18 g) after receiving Cdt venom (1 microgram Cdt venom containing 0.6 microgram protein) at the doses indicated. A dose of Cdt venom above 0.9 microgram (ip) or 1 microgram (im) induced muscular contraction and above 1.2 micrograms (ip) or 5.5 micrograms (im) the venom induced muscular contraction and hind limb paralysis. Cdt venom above 2.5 micrograms (ip) or 9 micrograms (im) induced all these symptoms and 95 to 100% death in experimental animals. The lethal dose 50% of the Cdt venom used was 8 micrograms (im) and 1.5 micrograms (ip). In in vitro studies, 4 mg gangliosides neutralized the effect of up to 1.5 micrograms Cdt venom. Quantities as low as 0.2 mg gangliosides were capable of neutralizing 0.9 microgram of Cdt venom in vitro. Intramuscular treatment with 1 mg gangliosides performed 60 min after the intramuscular injection of 5 micrograms Cdt venom protected 100% of the animals. In contrast, no protection was achieved with intraperitoneal treatment with gangliosides. The data show that gangliosides were effective in neutralizing the toxic effects induced by Crotalus durissus terrificus venom both in vitro and in vivo and that post-exposure intramuscular treatment with gangliosides could protect animals experimentally inoculated with the venom.

Animals↗
PubMedDate not supplied

Antivenom activity of opossum (Didelphys marsupialis) serum fractions against Uracoan rattlesnake (Crotalus vegrandis Klauber, 1941) venom.

In this work, we have found strong evidence for the presence of an opossum serum which is highly proficient in inactivating the neurotoxic fractions of Uracoan rattlesnake (Crotalus vegrandis) venom. Analyses of strained electrophoretic patterns of SDS gels run in non-reducing conditions revealed a small group of antivenom proteins in 0.1 M DEAE cellulose fraction that was not found in 0.05 M, 0.02 M, 0.25 M and 0.3 M NaCl ionic strength. Neutralizing activities to mapanare (Bothrops lanceolatus) venom have been already described but this is the first time that opossum serum anticrotalus activity is found. In spite of having preliminary results, we wish to make the corresponding report, while we accomplish the purification of the neutralizing component. One protein isolated from opossum serum or a synthetic peptide based on the aforementioned protein would probably be very useful in medical management of Crotalus vegrandis accidents.

Animals↗
PubMed1976

Isolation of myotoxic component from rattlesnake (Crotalus viridis viridis) venom. Electron microscopic analysis of muscle damage.

The pathogenesis of myonecrosis induced by a purified component of rattlesnake (Crotalus viridis viridis) venom was studied at the light and electron microscopic levels. Crude venom was fractionated by gel filtration (Sephadex G-50) followed by cation exchange chromatography (Sephadex C-25). Electrophoretic homogeneity of the isolated myotoxin (Fraction II from C-25 column) was demonstrated in isoelectric focusing and disc gel polyacrylamide gel electrophoresis. White mice were injected intramuscularly with 1.5 mug/g of the purified protein in 0.1 ml of physiologic saline. Light microscopic examination of injected muscle revealed a series of degenerative events including partial vacuolation of muscle cells at 6, 12, and 24 hours and complete vacuolation and loss of striations at 48 and 72 hours. Hemorrhage was not observed. At the electron microscopic level the perinuclear space and sarcoplasmic reticulum were dilated in all samples. By 48 and 72 hours the myofibrils lacked striations and the sarcomeres were disorganized. Plasma membranes and T tubules remained intact in all samples. These results correlated well with the myonecrosis induced by crude Crotalus viridis viridis venom except for several important aspects. The pure component altered skeletal muscle cells specifically, with the sarcoplasmic reticulum being the primary site of action.

Animals↗
PubMed2005

Sexual size dimorphism and growth plasticity in snakes: an experiment on the Western Diamond-backed Rattlesnake (Crotalus atrox).

We conducted an experiment to examine the effects of sex and food intake on growth, mass gain, and attainment of sexual maturity in Western Diamond-backed Rattlesnakes (Crotalus atrox). We also measured testosterone levels to determine whether testosterone might be involved in the male-biased sexual size dimorphism observed in this species. We collected neonate rattlesnakes and raised them in the laboratory for 2 years on either a high-intake diet (fed one mouse per week) or a low-intake diet (fed one mouse every 3 weeks). High-intake snakes grew and gained mass more rapidly than low-intake snakes, but males did not grow or gain mass more rapidly than females in either treatment group. High-intake snakes attained reproductive maturity earlier than low-intake snakes, indicating that size, not age, is the critical determinant of reproductive maturity. Males had higher levels of testosterone than females but did not grow more quickly, suggesting that testosterone may not affect growth in this species and may therefore not be the proximate determinant of sexual size dimorphism.

Animal Nutritional Physiological Phenomena↗
PubMed2007

Mechanisms controlling venom expulsion in the western diamondback rattlesnake, Crotalus atrox.

Although many studies have documented variation in the amount of venom expended during bites of venomous snakes, the mechanistic source of this variation remains uncertain. This study used experimental techniques to examine how two different features of the venom delivery system, the muscle surrounding the venom gland (the Compressor Glandulae in the rattlesnake) and the fang sheath, could influence venom flow in the western diamondback rattlesnake, Crotalus atrox. Differential contraction of the Compressor Glandulae explained only approximately 30% of the variation in venom flow. Lifting (compression) of the fang sheath as occurs during a normal strike produced marked increases in venom flow; these changes were closely correlated and exceed in magnitude by almost 10 x those recorded from the Compressor Glandulae alone. These results suggest that variation in these two aspects of the venom delivery system--both in terms of magnitude and temporal patterning--explain most of the observed variation in venom injection. The lack of functional or mechanical links between the Compressor Glandulae and the fang sheath, and the lack of skeletal or smooth muscle within the fang sheath, make it unlikely that variation in venom flow is under direct neural control. Instead, differential venom injection results from differences in the pressurization by the Compressor Glandulae, the gate keeping effects of the fang sheath and enclosed soft-tissue chambers, and by differences in the pressure returned by peripheral resistance of the target tissue.

Animals↗
PubMed1998

Isolation, sequence analysis, and biological activity of atrolysin E/D, the non-RGD disintegrin domain from Crotalus atrox venom.

Crotalid snake venom metalloproteinases often have associated with them nonproteinase domains that may be processed from the mature proteinases. Nascent atrolysin E, from the western diamondback rattlesnake, Crotalus atrox, has a metalloproteinasedomain and a non-RGD disintegrin domain that is lacking in the mature metalloproteinase. In this studywe report on the isolation, sequence analysis, andbiological activity of the 7.4-kDa atrolysin E disintegrin domain (atrolysin E/D). Atrolysin E/D represents approximately 0.2% of the total protein fromthe crude venom. The protein begins with a glycinyl residue found in the latter part of the spacer region. The sequence of atrolysin E/D is identical to thatof the non-RGD disintegrin domain of atrolysin E. The structure is termed a non-RGD disintegrin sincein lieu of the characteristic RGD sequence, a Met-Val-Asp (MVD) is found instead. Nevertheless, the protein is a potent inhibitor of both collagen- and ADP-stimulated platelet aggregation with IC50 values of 4 and 8 nM, respectively. A cyclized synthetic peptide, Ac-CRVSMVDRNDDTC-NH2, which represents the sequence of the atrolysin E/D non-RGD loop, was demonstrated to be an effective inhibitor of platelet aggregation. Therefore, this region of atrolysin E/D's structure, as in the disintegrins proper, is important for the biological activity of the protein. Thus, like the non-RGD disintegrin barbourin from Sistrurus miliarius barbouri, a RGD sequence in the context of the disintegrin protein backbone is not an absolute requirement for platelet aggregation inhibitory activity. These data underscore the biochemical and functional complexity of crotalid snake venoms due to differential proteolytic processing of the precursor metalloproteinases and exemplify how the processed fragments may contribute to the observed pathological effects of the venom.

Adenosine Diphosphate↗
PubMed1994

Isolation of multiple isoforms of alpha-fibrinogenase from the Western diamondback rattlesnake, Crotalus atrox: N-terminal sequence homology with ancrod, an antithrombotic agent from Malayan viper.

Three fibrinogenolytic proteases from the rattlesnake (Crotalus atrox) venom were isolated and purified from multiple-step chromatographies including ion-exchange chromatography, gel permeation and reversed-phase HPLC. The fractions were shown to be homogeneous as judged by SDS-gel electrophoresis. In vitro, they also showed a high and specific proteolytic activity against alpha-chains of fibrinogen molecules. Further characterization of these purified fractions with fibrinogenase activity indicated that they are all single-chain proteins with similar molecular weights of about 33,000-35,000. Their stability at high temperatures was examined and the cleavage specificity of various proteases was studied using oxidized insulin B-chains as substrates. The reactivity toward fibrinogen molecules in the presence of varied protease inhibitors including EDTA, beta-mercaptoethanol, soybean trypsin inhibitor, aprotinin and phenylmethanesulfonyl fluoride was also investigated in order to classify these proteases based on their reaction mechanisms. Amino acid analysis indicates that these purified venom toxins possess closely-similar compositions with regard to most amino acids including cysteine, methionine and tyrosine. N-Terminal sequence analysis of these proteases revealed that they are similar to ancrod, an antithrombotic agent isolated from the Malayan pit viper. This study points to the existence of a family of novel ancrod-like fibrinogenases in crotalid rattlesnakes, which may be useful as effective venom-based anticoagulants.

Amino Acid Sequence↗
PubMed2004

Direct organogenesis of Mandevilla illustris (Vell) Woodson and effects of its aqueous extract on the enzymatic and toxic activities of Crotalus durissus terrificus snake venom.

In order to produce explants of Mandevilla illustris (Vell) Woodson for the "Cerrado in vitro", the Germplasm Bank of UNAERP, we carried out a micropropagation protocol using MS or MS/3 medium supplemented with different concentrations of 6-benzyladeninepurine (BA), Zeatin or 2-isopentenyladenine for nodal segment growth, and alpha-naphthaleneacetic acid, indole-3-butyric acid (IBA) or 1,4 dithiothreitol for rooting. For nodal segments, all the cytokinins tested yielded similar results. However, 2.22 micro M BA is more economical to use. MS/3 medium supplemented with 0.49 micro M IBA was the most appropriate medium for rooting, resulting in 29% rooted explants. The crude aqueous extract from the subterranean system (SS) of M. illustris was assayed for its inhibitory action on the enzymatic activity of Crotalus durissus terrificus snake venom, isolated basic phospholipase A2 (CB) and crotoxin. It totally inhibited the phospholipase activity of crude Cdt venom and CB toxin and inhibited the phospholipase activity of crotoxin by 49%. The toxic action of both the crude venom and crotoxin was partially inhibited-there was a prolonged survival time and a 40.0% decrease in lethality.

Animals↗
PubMed2006

Behavioural examination of the infrared sensitivity of rattlesnakes (Crotalus atrox).

Pitvipers (Crotalinae) and boid snakes (Boidae) possess highly sensitive infrared (IR) receptors. The ability of these snakes to image IR radiation allows the assessment of the direction and distance of an IR source (such as warm-blooded prey) in the absence of visual cues. The aim of this study was to determine the behavioural threshold of snakes to an IR stimulus. A moving IR source of constant size and temperature was presented to rattlesnakes (Crotalus atrox) at various distances (10-160 cm) from their snout. The snakes' responses were quantified by measuring distinct behavioural changes during stimulus presentation (head jerks, head fixed, freezing, rattling and tongue-flicking). The results revealed that C. atrox can detect an artificial IR stimulus resembling a mouse in temperature and size up to a distance of 100 cm, which corresponds to a radiation density of 3.35 x 10(-3) mW/cm2. These behavioural results reveal a 3.2 times higher sensitivity to IR radiation than earlier electrophysiological investigations.

Animals↗
PubMed2004

The ventilatory response to environmental hypercarbia in the South American rattlesnake, Crotalus durissus.

To study the effects of environmental hypercarbia on ventilation in snakes, particularly the anomalous hyperpnea that is seen when CO(2) is removed from inspired gas mixtures (post-hypercapnic hyperpnea), gas mixtures of varying concentrations of CO(2) were administered to South American rattlesnakes, Crotalus durissus, breathing through an intact respiratory system or via a tracheal cannula by-passing the upper airways. Exposure to environmental hypercarbia at increasing levels, up to 7% CO(2), produced a progressive decrease in breathing frequency and increase in tidal volume. The net result was that total ventilation increased modestly, up to 5% CO(2) and then declined slightly on 7% CO(2). On return to breathing air there was an immediate but transient increase in breathing frequency and a further increase in tidal volume that produced a marked overshoot in ventilation. The magnitude of this post-hypercapnic hyperpnea was proportional to the level of previously inspired CO(2). Administration of CO(2) to the lungs alone produced effects that were identical to administration to both lungs and upper airways and this effect was removed by vagotomy. Administration of CO(2) to the upper airways alone was without effect. Systemic injection of boluses of CO(2)-rich blood produced an immediate increase in both breathing frequency and tidal volume. These data indicate that the post-hypercapnic hyperpnea resulted from the removal of inhibitory inputs from pulmonary receptors and suggest that while the ventilatory response to environmental hypercarbia in this species is a result of conflicting inputs from different receptor groups, this does not include input from upper airway receptors.

Analysis of Variance↗