Purification and characterisation of a haemorrhagic fraction from the venom of the Uracoan rattlesnake Crotalus vegrandis

A Review of Rattlesnake Venoms

Venom components are invaluable in biomedical research owing to their specificity and potency. Many of these components exist in two genera of rattlesnakes, Crotalus and Sistrurus, with high toxicity and proteolytic activity variation. This review focuses on venom components within rattlesnakes, and offers a comparison and itemized list of factors dictating venom composition, as well as presenting their known characteristics, activities, and significant applications in biosciences. There are 64 families and subfamilies of proteins present in Crotalus and Sistrurus venom. Snake venom serine proteases (SVSP), snake venom metalloproteases (SVMP), and phospholipases A2 (PLA2) are the standard components in Crotalus and Sistrurus venom. Through this review, we highlight gaps in the knowledge of rattlesnake venom; there needs to be more information on the venom composition of three Crotalus species and one Sistrurus subspecies. We discuss the activity and importance of both major and minor components in biomedical research and drug development.

South American snake venoms with abundant neurotoxic components. Composition and toxicological properties. A literature review

In South America there are three snake genera with predominantly neurotoxic venoms: Crotalus, Micrurus and Hydrophis, which include nine species/subspecies, 97 species and a single marine species, respectively. Although accidents with neurotoxic venoms are less frequent than those with anticoagulant, cytotoxic or necrotic venoms (e.g. from Bothrops), they are of major public health importance. Venoms from genus Crotalus have been extensively studied, while data on the venoms from the other two genera are very limited, especially for Hydrophis. The venoms of North and South American Crotalus species show biochemical and physiopathological differences. The former species cause bothrops-like envenomation symptoms, while the latter mainly have neurotoxic and myotoxic effects, leading to respiratory paralysis and, occasionally, renal failure by myoglobinuria and death, often with no local lesions. Micrurus and Hydrophis also cause neurotoxic envenomations. Many studies have isolated, identified and characterized new enzymes and toxins, thus expanding the knowledge of snake venom composition. The present review summarizes the currently available information on neurotoxic venoms from South American snakes, with a focus on protein composition and toxicological properties. It also includes some comments concerning potential medical applications of elapid and crotalic toxins.

A Meta-Analysis of the Protein Components in Rattlesnake Venom

The specificity and potency of venom components give them a unique advantage in developing various pharmaceutical drugs. Though venom is a cocktail of proteins, rarely are the synergy and association between various venom components studied. Understanding the relationship between various components of venom is critical in medical research. Using meta-analysis, we observed underlying patterns and associations in the appearance of the toxin families. For Crotalus, Dis has the most associations with the following toxins: PDE; BPP; CRL; CRiSP; LAAO; SVMP P-I and LAAO; SVMP P-III and LAAO. In Sistrurus venom, CTL and NGF have the most associations. These associations can predict the presence of proteins in novel venom and understand synergies between venom components for enhanced bioactivity. Using this approach, the need to revisit the classification of proteins as major components or minor components is highlighted. The revised classification of venom components is based on ubiquity, bioactivity, the number of associations, and synergies. The revised classification can be expected to trigger increased research on venom components, such as NGF, which have high biomedical significance. Using hierarchical clustering, we observed that the genera's venom compositions were similar, based on functional characteristics rather than phylogenetic relationships.

Hemostatic and toxinological diversities in venom of Micrurus tener tener, Micrurus fulvius fulvius and Micrurus isozonus coral snakes

The coral snake Micrurus tener tener (Mtt) from the Elapidae family inhabits the southwestern United States and produces severe cases of envenomations. Although the majority of Mtt venom components are neurotoxins and phospholipase A₂s, this study demonstrated, by SDS-PAGE and molecular exclusion chromatography (MEC), that these venoms also contain high-molecular-weight proteins between 50 and 150 kDa that target the hemostatic system. The biological aspects of other Micrurus venoms were also studied, such as the LD₅₀s of Micrurus isozonus (from 0.52 to 0.61 mg/kg). A pool from these venoms presented a LD₅₀ of 0.57 mg/kg, Micrurus f. fulvius (Mff) and Mtt had LD₅₀s of 0.32 and 0.78 mg/kg, respectively. These venoms contained fibrino(geno)lytic activity, they inhibited platelet aggregation, as well as factor Xa and/or plasmin-like activities. M. isozonus venoms from different Venezuelan geographical regions inhibited ADP-induced platelet aggregation (from 50 to 68%). Micrurus tener tener venom from the United States was the most active with a 95.2% inhibitory effect. This venom showed thrombin-like activity on fibrinogen and human plasma. Fractions of Mtt showed fibrino(geno)lytic activity and inhibition on plasmin amidolytic activity. Several fractions degraded the fibrinogen Aα chains, and fractions F2 and F7 completely degraded both fibrinogen Aα and Bβ chains. To our knowledge, this is the first report on thrombin-like and fibrino(geno)lytic activity and plasmin or factor Xa inhibitors described in Micrurus venoms. Further purification and characterization of these Micrurus venom components could be of therapeutic use in the treatment of hemostatic disorders.

Purification and characterization of a metalloproteinase, Porthidin-1, from the venom of Lansberg's hog-nosed pitvipers (Porthidium lansbergii hutmanni)

Porthidium lansbergii hutmanni is a small pit viper found on Margarita Island, Venezuela. Local tissue damage is one of the most obvious characteristics of P. l. hutmanni envenomation, which can lead to diverse pathological effects, such as hemorrhage, edema, blistering, necrosis, lymphatic vessel damage and degradation of extracellular matrix. Metalloproteinases are one of the major components in venoms responsible for these effects. To date, very little is known or has been reported on P. l. hutmanni venom. Crude P. l. hutmanni venom had a LD(50) of 2.5 mg/kg and was considered very hemorrhagic (minimal hemorrhagic dose [MHD]: 0.98 μg) when compared to other hemorrhagic (Bothrops) venoms in Venezuela. Crude P. l. hutmanni venom also inhibited ADP-induced platelet aggregation. A metalloproteinase, Porthidin-1, from this venom was isolated by three chromatography steps (Sephadex G100, Superose 12 HR10/30 and Bioscale Q2). Porthidin-1 falls in the SVMP P-I class having a molecular weight of 23 kDa, verified by both SDS-PAGE and mass spectrometry. High-resolution mass spectrometry and a database search identified a peptide from Porthidin-1 (YNGDLDK) belonging to the SVMP family of proteins. Porthidin-1 contained hemorrhagic, fibrino(geno)lytic, caseinolytic and gelatinolytic activities, and these activities were capable of being neutralized by metalloproteinase inhibitors but not serine proteinase inhibitors. The peptide YNGDLDK shared similarities with five venom proteins with a BLAST e-value of <1. This work details the biochemical and pathophysiological effects that can result from envenomations, and highlights the importance and significance for characterizing unknown or poorly documented venoms from different geographical regions.

Purification and characterization of a new weak hemorrhagic metalloproteinase BmHF-1 from Bothrops marajoensis snake venom

BmHF-1, from the venom of Bothrops marajoensis, was purified by Sephadex G-75 and HPLC-RP on micro-Bondapak C-18 column chromatography. It presented a molecular mass of 27162.36 Da determined by MALDI-TOF MS. BmHF-1 had a sequence of 238 residues of amino acids. The multiple alignment of its amino acid sequence and those of other snake venom metalloproteinases showed high structural similarity, mainly among P-I class. The enzyme initially cleaves the Aalpha-chain of fibrinogen, followed by the Bbeta-chain, and shows no effects on the gamma-chain. BmHF-1 had, caseinolytic and weakly hemorrhagic activities, which were inhibited by EDTA. In contrast, PMSF did not affect these activities. The caseinolytic activity of BmHF-1 had a pH optimum of 8.0 and was stable in solution up to 40 degrees C; activity was completely lost at > or = 70 degrees C. The proteolytic activity was also inhibited by sDa (opossum sera) and Da2-1, Da2-II, antihemorrhagic factors isolated from the opossum sera of Didelphis albiventris. BmHF-1 presents weak hemorrhagic activity, with a MHD of 41.14 microg and it induces dose-dependent edema. We could concluded that, despite its weak hemorrhagic activity, BmHF-1 contributes to local tissue damage by inducing edema, releasing pharmacologically active mediators from protein precursors due to its enzymatic action.

The effect of different snake venoms and anti-venoms on thrombin clotting time in human plasma

BACKGROUND

Crotaline snake species, or pit vipers, are distributed throughout Asia and America. While much is known about the clinical effect of these snake venoms, there is a lack of evidence related to the various anti-venoms available and their effectiveness in reversing the effect of different venoms.

AIM

This study aimed to determine the interaction of the venoms of the following species: Crotalus unicolor, Crotalus adamanteus, Crotalus vegrandis, Trimeresurus spp, Calloselasma rhodostoma, Bothriechis schlegelii and Agkistrodon and the following anti-venoms: Anticrotalico, Antivipmyn, Antibotropico, Antifidico and SAIMR by evaluating their effect on the thrombin clotting time in human plasma.

METHOD

The interactions of venoms and anti-venoms were evaluated using thrombin clotting time in human plasma.

RESULTS

The results demonstrate that Anticrotalico anti-venom was most effective for the Crotalid species (Crotalus unicolor, Crotalus adamanteus, Crotalus vegrandis). Anticrotalico extended the time to clot formation 2.7 fold for Crotalus Unicolor, 3 fold for Crotalus Adamanteus and 4.6 fold for Crotalus Vegrandis. The anti-venoms most efficient in reversing the effect of the Trimeresurus spp venom, were Anticrotalico, Antivipmyn, Antibotropico and Antifidico anti-venoms, which all completely reversed the effect of clot formation as evident by no clot formation within the 999 seconds measurement limit. Bothriechis schlegelii venom was neutralized by all anti-venoms tested. Calloselasma rhodostoma venom was neutralized by Antifidico as well as Anticrotalico. The most efficient anti-venoms against the Agkistrodon venom were Anticrotalico and Antibotropico. In general, monovalent anti-venoms had improved efficiency for their corresponding snake species, depending highly on the composition of the snake venom. This study confirms the importance of considering the choice of anti-venom in a clinical setting, to reverse the effect of specific snake venoms. In addition, this study suggests that some anti-venoms can be considered for use against a variety of snake-venoms.

Isolation and biological characterization of Batx-I, a weak hemorrhagic and fibrinogenolytic PI metalloproteinase from Colombian Bothrops atrox venom

A hemorrhagic metalloproteinase, named Batx-I, was isolated from the venom of Bothrops atrox specimens (from Southeastern Colombian region) by a combination of CM-Sephadex C25 ion-exchange and Affi-gel Blue affinity chromatographies. This enzyme accounts for about 45% of venom proteins, and it has an ESI-MS isotope-averaged molecular mass of 23296.2 Da and a blocked N-terminus. Two internal fragments sequenced by mass spectrometric analysis showed similarity to other SVMPs from Bothrops venoms. To investigate the possible participation of Batx-I in the envenomation pathophysiology, proteolytic, fibrinogenolytic, hemorrhagic, and other biological activities were evaluated. The minimal hemorrhagic dose obtained was 17 microg/20 g body weight. The enzyme showed proteolytic activity on azocasein, comparable with activity of BaP1. This activity was inhibited by EDTA and 1, 10 o-phenanthroline but not by aprotinin, pepstatin A or PMSF. Fibrinogenolytic activity was analyzed by SDS-PAGE, revealing a preference for degrading the A alpha- and B beta-chains, although partial degradation of the gamma-chain was also detected. The protein lacks coagulant and defibrinating activity. The CK levels obtained, clearly reflects a myotoxic activity induced by Batx-I. The hemorrhagic and fibrinogenolytic activities exhibited by the isolated PI-SVMP may play a role in the hemorrhagic and blood-clotting disorders observed in patients bitten by B. atrox in Colombia.

Purification and biochemical characterization of a novel hemorrhagic metalloproteinase from horned viper (Cerastes cerastes) venom

Snake venoms contain metalloproteinases that contribute to the local effects observed after envenoming. In this study, a hemorrhagic metalloproteinase (CcH1) was purified from Cerastes cerastes venom by a combination of gel filtration, ion exchange, affinity and RP-HPLC chromatography. The hemorrhagin was homogeneous on SDS-PAGE, with a molecular mass of 25 kDa. Isoelectric focusing revealed a pI of 5.5. CcH1 displayed hemorrhagic and proteolytic activities, but no esterolytic activity. The hemorrhagic and proteolytic activities of CcH1 were inhibited by EDTA and 1,10-phenanthroline, but not by PMSF, suggesting that this protein is a zinc-metalloproteinase. Furthermore, the hemorrhagic and proteolytic activities of CcH1 were stable in solution at up to 40 degrees C, with a loss of activity at > or =70 degrees C. The molecular mass and the inhibition assays suggest that the metalloproteinase CcH1 belongs to class P-I of SVMPs.

Anti-platelet effect of cumanastatin 1, a disintegrin isolated from venom of South American Crotalus rattlesnake

Disintegrins have been previously described in the venom of several snake families inhibiting signal transduction, cell-cell interactions, and cell-matrix interactions and may have therapeutic potential in heart attacks, thrombotic diseases, and cancers. This investigation describes the first disintegrin isolated from South American Crotalus venom (Venezuelan rattlesnake Crotalus durissus cumanensis), which inhibits platelet adhesion to matrix proteins. C. d. cumanensis crude venom was first separated on a Sephadex G-100 column into 4 fractions (SI to SIV). Crude venom and SIII fraction significantly diminished platelet adhesion to fibrinogen (Fg) and to fibronectin (Fn). Anti-adhesive SIII fraction was further separated by DEAE-Sephacel followed by C-18 reverse phase high performance liquid chromatography (HPLC). The platelet anti-adhesive fraction obtained was designated as cumanastatin-1. This disintegrin has a mass of 7.442 kDa as determined by mass spectrometry (MALDI-TOF/TOF) and pI of 8.5. Cumanastatin-1 also inhibited ADP-induced platelet aggregation with an IC(50) of 158 nM. However, it did not significantly inhibit collagen and thrombin-induced platelet aggregation. Cumanastatin-1 considerably inhibited anti-alpha(IIb)beta(3) integrin binding to platelets in a dose-dependent manner; however, it did not present any effect on the alpha(5)beta(1) integrin or on P-selectin.

Individual venom variability in the South American rattlesnake Crotalus durissus cumanensis

Crotalus durissus cumanensis snake venoms from different Venezuelan regions, showed biochemical and hemostatic variations. Fibrino(geno)lytic, hemorrhagic and procoagulant activities and gel-filtration chromatography and SDS-PAGE profiles were analyzed. Differences were observed in fibrinolytic activity: kallikrein-like amidolytic activity was highest in venoms of Santa Teresa, and Margarita. Lagunetica and Carrizales venoms showed the maximum fibrin lysis. The highest hemorrhagic activity was seen in Lagunetica venom. Margarita had the lowest LD(50) of 0.18. Lagunetica, Carrizales and Anzoátegui induced a rapid degradation of fibrinogen alpha chains and slower degradation on beta chains, which could possibly due to a higher content of alpha fibrinogenases in these venoms. This fibrinogenolytic activity is decreased by metalloprotease inhibitors. All venoms, except Carrizales, presented thrombin-like activity. Anzoátegui, Carrizales and Lagunetica, in which fibrinolytic activity was present, showed the largest concentration of high molecular mass components. These results represent a new finding, not previously described, of fibrinolytic activity in South American C. durissus venoms. Santa Teresa and Margarita had fibrinolytic activity, and lack of hemorrhagic activity, representing an important finding in Venezuelan venoms since the description of a fibrinolytic molecule without hemorrhagic activity can have valuable potential in thrombolytic therapy.

Alterations in the ultrastructure of cardiac autonomic nervous system triggered by crotoxin from rattlesnake (Crotalus durissus cumanensis) venom

This study explored the toxic effects of crotoxin isolated from Crotalus durissus cumanensis venom on the ultrastructure of mice cardiac autonomic nervous system. Mice were intravenously injected with saline (control group) and crotoxin diluted in saline venom (study group) at a dose of 0.107 mg/kg mouse body weight. Samples from the inter-ventricular septum were prepared for electron microscopy after 6 h (G1), 12 h (G2), 24 h (G3) and 48 h (G4). The G1 group showed some cardiomyocyte with pleomorphic mitochondria. Capillary swollen walls, nerve cholinergic endings with depleted acetylcholine vesicles in their interior and other depletions were observed. A space completely lacking in contractile elements was noticed. The G2 group demonstrated a myelinic figure, a subsarcolemic region with few myofibrils and nervous cholinergic terminal with scarce vacuoles in their interior. The G3 group demonstrated a structure with a depleted axonic terminal, mitochondrias varying in size and enhanced electron density. In addition, muscular fibers with myofibrillar structure disorganization, a depleted nervous structure surrounded by a Schwann cell along with an abundance of natriuretic peptides, were seen. An amyelinic terminal with depleted Schwann cell and with scarce vesicles was also observed. Finally, axonic lysis with autophagic vacuoles in their interior and condensed mitochondria was observed in the G4 group. This work describes the first report of ultrastructural damage caused by crotoxin on mice cardiac autonomic nervous system.

Characterisation of the fibrinogenolytic properties of the buccal gland secretion from Lampetra japonica

Lampetra japonica is representative of the ancient cyclostomota class of animals, and its buccal gland secretion (called lamphredin) is known to act as an anticoagulant. In this study, it was observed by both native-PAGE and SDS-PAGE that the secretion mainly contained two protein bands, buccal gland secretion protein-1 (BGSP-1, 159,909 Da) and buccal gland secretion protein-2 (BGSP-2, 25,660 Da). The N-terminal amino acids of BGSP-1 (EAESF QNLKT RICGG LNGLG) and BGSP-2 (TSVND WKLLD TKLSA NRKVI) were sequenced. Using a Sephadex G-75 column, we isolated BGSP-1, BGSP-2 and small peptides from the buccal gland secretion, but found only BGSP-1 showed fibrinogenolytic activity. BGSP-1 and lamphredin were found to rapidly degrade the alpha chain of human fibrinogen, slowly degrade the beta chain and hardly degrade the gamma chain. BGSP-1 and lamphredin showed a similar map by SDS-PAGE for the degradation of fibrinogen by cleavage at Ala(10)-Glu(11) and His(368)-Ser(369). BGSP-1 was also found to hydrolyze neuronal protein tau at Glu(12)-Asp(13) and Gln(244)-Thr(245). Further study showed that lamphredin and BGSP-1 were inactivated in the presence of a metal chelating agent EDTA. However, addition of Ca(2+) or Mg(2+) but not Zn(2+) restored the fibrinogenolytic activity. This suggests that BGSP-1 acts in the buccal gland as a metalloproteinase with a broad substrate specificity. Furthermore, the secretion showed cytolytic properties towards human SH-SY5Y and HeLa cells in culture, and lamphredin at a 50-fold dilution induced cell death.

Experimental ophitoxemia produced by the opisthoglyphous lora snake (Philodryas olfersii) venom

Several colubrid snakes produce venomous oral secretions. In this work, the venom collected from Venezuelan opisthoglyphous (rear-fanged) Philodryas olfersii snake was studied. Different proteins were present in its venom and they were characterized by 20% SDS-PAGE protein electrophoresis. The secretion exhibited proteolytic (gelatinase) activity, which was partially purified on a chromatography ionic exchange mono Q2 column. Additionally, the haemorrhagic activity of Philodryas olfersii venom on chicken embryos, mouse skin and peritoneum was demonstrated. Neurotoxic symptoms were demonstrated in mice inoculated with Philodryas olfersii venom. In conclusion, Philodryas olfersii venom showed proteolytic, haemorrhagic, and neurotoxic activities, thus increasing the interest in the high toxic action of Philodryas venom.

A low-cost method to test cytotoxic effects of Crotalus vegrandis (Serpentes: Viperidae) venom on kidney cell cultures

The pathogenesis of the renal lesion upon envenomation by snakebite has been related to myolysis, hemolysis, hypotension and/or direct venom nephrotoxicity caused by the venom. Both primary and continuous cell culture systems provide an in vitro alternative for quantitative evaluation of the toxicity of snake venoms. Crude Crotalus vegrandis venom was fractionated by molecular exclusion chromatography. The toxicity of C. vegrandis crude venom, hemorrhagic, and neurotoxic fractions were evaluated on mouse primary renal cells and a continuous cell line of Vero cells maintained in vitro. Cells were isolated from murine renal cortex and were grown in 96 well plates with Dulbecco's Modified Essential Medium (DMEM) and challenged with crude and venom fractions. The murine renal cortex cells exhibited epithelial morphology and the majority showed smooth muscle actin determined by immune-staining. The cytotoxicity was evaluated by the tetrazolium colorimetric method. Cell viability was less for crude venom, followed by the hemorrhagic and neurotoxic fractions with a CT50 of 4.93, 18.41 and 50.22 µg/mL, respectively. The Vero cell cultures seemed to be more sensitive with a CT50 of 2.9 and 1.4 µg/mL for crude venom and the hemorrhagic peak, respectively. The results of this study show the potential of using cell culture system to evaluate venom toxicity.

Purification and characterization of a hemorrhagic metalloproteinase from Bothrops lanceolatus (Fer-de-lance) snake venom

Bothrops snake venoms contain metalloproteinases that contribute to the local effects seen after envenoming. In this work, a hemorrhagic metalloproteinase (BlaH1) was purified from the venom of the snake Bothrops lanceolatus by a combination of gel filtration, affinity (metal chelating) and hydrophobic interaction chromatographies. The hemorrhagin was homogeneous by SDS-PAGE and had a molecular mass of 28 kDa that was unaltered by treatment with beta-mercaptoethanol. BlaH1 gave a single band in immunoelectrophoresis and immunoblotting using commercial bothropic antivenom. BlaH1 had hemorrhagic, caseinolytic, fibrinogenolytic, collagenolytic and elastinolytic activities, but no phospholipase A(2) activity. The hemorrhagic and caseinolytic activities were inhibited by EDTA, indicating that they were metal ion-dependent. In contrast, aprotinin, benzamidine and PMSF did not affect these activities. The caseinolytic activity of BlaH1 had a pH optimum of 8.0 and was stable in solution at up to 40 degrees C; activity was completely lost at > or =70 degrees C. The hemorrhagic activity was neutralized by commercial bothropic antivenom. These properties suggest that this new hemorrhagin belongs to class P-I snake venom metalloproteinases.

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.