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At least 127 records · Page 7Linked to original sources

PubMed1992

Age changes of Vipera berus venom amidolytic activity.

The study of age changes of amidolytic activity of Vipera berus venom is investigated using mixtures of chromogenic peptide substrates differing by detected groups. Quantities of venom (total protein content) and its proteolytic activity from snakes of different ages were compared. The venom composition of newly born adders was shown to be considerably different from the venom composition of young (12-month) adders of the same population. The next evolution of protease activity is weakly expressed.

Aging↗

PubMed1993

Low molecular weight factor X activator from Cerastes vipera (Sahara sand viper) venom.

Fraction G from Cerastes vipera venom previously purified on Sephadex G100 was refractionated on DEAE-Sephadex A50 column. A factor X activator was obtained. It had a mol. wt of 12,500 and an isoelectric point of 4.4. It shortened the plasma recalcification time of normal plasma, and plasmas deficient in factors V, VII, VIII, IX, XI and XIII, while it had no effect on plasma deficient in factor X or factor II. It had a serine protease activity and a minimal plasmin activity. PMSF, leupeptin and iodoacetamide exerted a pronounced inhibitory effect on its serine protease activity. Polyantivenin could neutralize the coagulant activity of the activator.

Amino Acid Sequence↗

PubMed1993

Purification and partial characterization of a haemorrhagin (VRH-1) from Vipera russelli russelli venom.

A haemorrhagic toxin (VRH-1) has been purified to homogeneity from Vipera russelli russelli venom by subjecting it to chromatography twice successively on CM-Sephadex C-50. It is a protein of mol. wt 22,000 and contains one mole of Mg2+. Intradermal administration of this haemorrhagin in mice resulted in severe lung haemorrhage but produced little haemorrhage in skin. This apparent organ preference led us to develop a new haemorrhage assay method utilizing dye diffusion from lung in vitro. Proteolytic activity of VRH-1 was demonstrated using dimethylcasein as substrate following quantitation by reaction with trinitrobenzoyl sulfonic acid. Both haemorrhagic and proteolytic activities of VRH-1 were inhibited by serine protease inhibitors like phenylmethyl sulfonyl fluoride and chymostatin, but metal chelators had no effect. Lung haemorrhage is unlikely to be a direct reflection of a high local concentration of VRH-1. The administration of supernatant generated by incubation of chopped liver from untreated mouse and VRH-1 (in subhaemorrhagic dose) results in severe lung haemorrhage. This raises the possibility that VRH-1 leads to the formation of intermediate(s) which causes the haemorrhage.

Amino Acids↗

PubMed1993

Myocarditis following envenoming with Vipera palaestinae in two horses.

Cardiac disease developed several days to weeks after resolution of local inflammation caused by envenoming by Vipera palaestinae in two horses. In one horse (case A), referred to the hospital for recurrent abdominal pain 8 days after envenoming, a tachyarrhythmia was detected; ventricular premature depolarizations were diagnosed by ECG. A second horse (case B) was found dead without premonitory signs 60 days after envenoming. In both horses, there was extensive necrosis of cardiac ventricular tissues.

Animals↗

PubMed1995

Medium molecular weight factor X activating enzyme from Vipera berus berus venom.

Vipera berus berus venom contains several factor X activating enzymes. One of them (VBFXAE) was separated by gel-filtration on Sephadex G-100 superfine and on a bacitracin-agarose column. The enzyme is a single-chain glycoprotein with mol. wt 38,000. The enzyme has several molecular forms with pI 3.5-4.5. After neuraminidase treatment the enzyme has pI 4.5. VBFXAE contains 2 Ca per mole. The activator is inactive on synthetic substrates, on casein, prothrombin, and fibrinogen, and appears to act specifically on factor X. The activator also weakly hydrolyses the insulin B-chain at the positions Ala14-Leu15 and Tyr16-Leu17. The cleavage of the insulin B-chain is inhibited by EDTA, suggesting the metalloproteinase nature of the enzyme.

Amino Acids↗

PubMed1994

Primary sequence determination of the most basic myonecrotic phospholipase A2 from the venom of Vipera russelli.

The most basic phospholipase A2 (PLA2), VRV-PL-VIIIa, was purified from (Sri Lankan) Vipera russelli venom. It is a major component of the venom, contributing over 40% to the whole venom PLA2 activity. The purity of VRV-PL-VIIIa was ascertained by electrophoresis and by reverse phase high-pressure liquid-chromatography (RP-HPLC). VRV-PL-VIIIa had an apparent mol. wt of 13,000 and was a single polypeptide. The protein was reduced, pyridylethylated and subjected to sequence analysis. The N-terminal amino acid sequence was established up to the 39th residue. Pyridylethylated VRV-PL-VIIIa was digested with endoprotease Glu-C, and several peptides were purified by RP-HPLC; six purified peptides were sequenced. The sequence of the C-terminal was established by sequencing a CNBr-produced peptide purified by RP-HPLC. Several peptides were also generated by digestion with endoprotease Asp-N. Two peptides were sequenced to obtain overlapping regions. The complete structure was deduced from sequences of overlapping peptides and through homology with other group II PLA2 sequences. Sequence homology was greatest with ammodytoxin A: 99 amino acid residues out of 121 occurred in identical positions. Myotoxin III of Bothrops asper showed 73% homology, 89 out of 121 residues. In agreement with the sequence data, polyclonal antiserum against VRV-PL-VIIIa cross-reacted in ELISA with ammodytoxin A and, to a lesser extent, with caudoxin.

Amino Acid Sequence↗

PubMed1994

Monoclonal antibodies to VRV-PL-VIIIa, a basic multitoxic phospholipase A2 from Vipera russelli venom.

VRV-PL-VIIIa, the most basic phospholipase A2 (PLA2) from the venom of Vipera russelli, induces multiple toxic effects, including neurotoxicity, myotoxicity, edema and hemorrhage. Rabbit polyclonal anti-serum was raised against VRV-PL-VIIIa. The antiserum cross-reacted in enzyme-linked immunosorbant assay (ELISA) with two other PLA2 from the same venom, VRV-PL-V and VRV-PL-VI, and with ammodytoxin A, caudoxin and crotoxin. Twenty-two hybridoma cell lines secreting monoclonal antibodies against VRV-PL-VIIIa were isolated. The monoclonal antibodies exhibited apparent binding affinities in ELISA with VRV-PL-VIIIa ranging over two orders of magnitude. Most of the monoclonal antibodies cross-reacted moderately with VRV-PL-V and weakly with VRV-PL-VI. None of the antibodies cross-reacted with ammodytoxin, caudoxin or crotoxin. Reducing the disulfide bonds of VRV-PL-VIIIa lowered the ELISA signals of each monoclonal antibody to nonspecific levels, suggesting that all the antibodies recognize conformational epitopes. Four of the 22 antibodies neutralized the enzymatic activity of VRV-PL-VIIIa. Interestingly, two of the four exhibited the lowest affinities of the monoclonal antibody library for VRV-PL-VIIIa in ELISA, while the other two exhibited the highest. Each of the monoclonal antibodies was biotinylated and spatial binding relationships were evaluated by competition ELISA.

Animals↗

PubMed1995

Some pharmacological studies on the effects of Cerastes vipera (Sahara sand viper) snake venom.

The effects of the venom of the Sahara sand viper (Cerastes vipera) were studied on isolated chick biventer cervicis, isolated rat atria and vas deferens preparations, and on the electrocardiogram of anaesthetized rats. Effects on 3H-noradrenaline uptake were studied using rat brain synaptosomes. At 50 micrograms/ml and 100 micrograms/ml, the venom caused a transient increase in rate and force of contractions of the rat atria followed by an irreversible depression. These effects were not prevented by atenolol, atropine or a combination of the two. In the presence of 25 microM lignocaine, the effects of venom on rat atria were reversible by washing. At 100 micrograms/ml, the venom transiently increased responses of vas deferens preparations to indirect stimulation, but had little effect on responses to noradrenaline, KCl, and ATP. In the presence of an alpha 1-adrenoceptor antagonist (prazosin) or a P2-purinergic receptor antagonist (suramin), the venom still significantly increased twitch height and responses to noradrenaline but not to KCl or ATP. The effect of the venom did not change after exposure to a combination of prazosin, suramin and tetrodotoxin. The venom (100 micrograms/ml) significantly decreased twitches to indirect and direct stimulation in chick biventer cervicis preparations. Responses to exogenously applied acetylcholine, carbachol and KCl were also decreased. Venom blocked the synaptosomal uptake of 3H-noradrenaline (IC50 = 5 micrograms/ml), and caused severe bradycardia in vivo. Some of the direct effects on muscle preparations are possibly due to the venom's phospholipase A2 activity.

Adrenergic alpha-Antagonists↗

PubMed1996

Development and clinical application of immunoassays for European adder (Vipera berus berus) venom and antivenom.

An ovine affinity purified Fab antivenom was used in a clinical trial in Sweden to treat European adder (Vipera berus berus) envenoming. Immunoassays were developed to measure V. b. berus venom and antivenom concentrations in clinical samples to help assess the efficacy of treatment. A radioimmunoassay (RIA) was developed, optimized and validated to measure plasma levels of V. b. berus venom and compared with a conventional ELISA. Both showed a similar variation of zero binding in biological samples and the results obtained correlated closely. However, the ELISA was quicker and more sensitive (0.8 compared with 2 micrograms/litre). Before administration of antivenom, V. b. berus venom concentrations in plasma ranged from 10 to 53 micrograms/litre; 12 hr after the Fab infusion, no patient had measurable levels. However, two patients had low venom levels 24 hr after treatment. ELISA and RIA were also developed, optimized and used to measure concentrations of free Fab in plasma. There was a biexponential fall of Fab concentration with a fast distribution phase (t 1/2 = 0.9 hr) and a slower elimination phase (t 1/2 = 18 hr). The amount of Fab excreted in urine was low.

Animals↗

PubMed1996

Effect of ammodytin L from the venom of Vipera ammodytes on Xenopus laevis differentiated muscle fibres and regenerating limbs.

Ammodytin L is a non-catalytic, phospholipase-like snake venom toxin from Vipera ammodytes, which shows a cytotoxic activity on differentiated myotubes when tested in vitro. In the range of concentrations in which ammodytin L induced necrosis of myogenic cells in culture, other cell types (erythrocytes, platelets, fibroblasts) did not appear to be affected. To test the in vivo toxicity and the effective cytolytic specificity of ammodytin L we have followed the morphological changes in muscle tissue of Xenopus laevis limbs after intramuscular toxin injection. Only muscular cells were affected by ammodytin L, and the toxin did not induce any morphological change in other cell types. Further evidence of the muscle-specific action of the toxin was obtained from experiments carried out using the Xenopus kidney cell line B3.2 in culture. Ammodytin L was unable to affect parameters of cell viability such as lactate dehydrogenase leakage, [3H]thymidine incorporation, growth curves and morphological changes. Moreover, direct ammodytin L application to cultured regenerative limbs did not provoke alterations in undifferentiated myoblasts. These data suggest that ammodytin L, like other phospholipase-like toxins, exerts its toxicity by selectively damaging differentiated muscle fibres.

Animals↗

PubMed1996

Cross-reactivities of polyclonal antibodies against lebetase, fibrinolytic enzyme of Levantine viper (Vipera lebetina) venom.

Antibodies to two fractions of fibrinolytic enzyme in Vipera lebetina venom were produced by immunizing mice with chromatographically purified lebetase probes. The antibodies were isolated from mice blood by protein A affinity chromatography. The antibodies to both fractions reacted only with the fibrinolytic enzyme in V. lebetina venom as demonstrated by western immunoblotting. Immunodot assays, ELISA and western immunoblotting revealed that 11 snake venoms including species of Viperidae and Crotalidae but not Elapidae cross-react with lebetase antibodies to varying degrees. The molecular weights of cross-reacting components were detected and compared with the earlier published data.

Animals↗

PubMed1996

A platelet aggregation inhibitor phospholipase A2 from Russell's viper (Vipera russelli) venom: isolation and characterization.

Vipera russelli venom is reported to contain multiple forms of phospholipase A2 (PLA2). Three PLA2s (VRV-PL-V, VRV-PL-VI and VRV-PL-VIIIa) have been purified and characterized in this laboratory. A PLA2(VRV-PL-IIIb) inhibiting platelet aggregation was purified from the same venom in two steps involving CM-Sephadex C-25 column chromatography followed by gel filtration on Sephadex G-50. VRV-PL-IIIb is a basic (pI 7.3-7.7) isoenzyme, with a mol. wt between 14,000 and 15,000. It induced neurotoxic symptoms in experimental mice with an i.p. LD50 of 5.2 mg/kg body weight. VRV-PL-IIIb inhibits ADP-induced platelet aggregation in a dose-dependent manner. It induced oedema in the foot pads of mice and is devoid of anticoagulant, myotoxic and direct haemolytic activities. Antibodies to VRV-PL-IIIb showed a single precipitin line against the antigen as well as whole venom.

Animals↗

PubMed1987

Monoclonal antibodies against Vipera lebetina venom nerve growth factor cross-react with other snake venom nerve growth factors.

Nerve growth factor (NGF) was isolated from the venom of Vipera lebetina and was purified to homogeneity as judged by SDS gel electrophoresis. The biologically active NGF was used to immunize BALB/c mouse, and the spleen cells from immunized mouse were fused with mouse PAI myeloma cells. Forty-seven hybrid cell lines, secreting monoclonal antibodies to V. lebetina NGF, were isolated and nine of them purified from ascitic fluids. The isolated antibodies define two partially overlapping epitopes of the V. lebetina NGF which are not involved in the biological activity of the molecule. Both epitopes are also present on the beta-NGF from the mouse salivary gland and on the NGFs from the following snake venoms: V. lebetina, V, ursini, V, berus berus, Echis carinatus, Bungarus caeruleus, Agkistrodon halys, Naja naja oxiana, Naja naja atra and Naja naja, but not on the bovine seminal plasma NGF. The mol. wts of the NGFs in these snake venoms were determined by Western immunoblot with monoclonal antibodies. The mol. wts of the NGFs from V. ursini (37,000), E. carinatus (36,000, 44,000) and A. halys (29,000) were determined for the first time.

Animals↗

PubMed1983

The primary structure of Vipera ammodytes venom trypsin inhibitor I.

The primary structure of Vipera ammodytes venom trypsin inhibitor I consists of 61 amino acid residues [sequence in text]. The N-terminal group of the inhibitor is pyrrolidonecarboxylic acid. The sequential data were obtained by analysis of peptides isolated from tryptic and chymotryptic digests and by analysis of peptides derived from the hydrolysis of the aspartyl-prolyl bond of the carboxymethylated inhibitor. The primary structure of trypsin inhibitor I presented shows approximately 80% sequence homology with chymotrypsin inhibitor isolated from the venom of the same snake, and nearly 50% homology with bovine basic pancreatic trypsin inhibitor. It belongs to the Kunitz-pancreatic trypsin inhibitor family of inhibitors.

Amino Acid Sequence↗

PubMed1984

Purification and properties of the main coagulant and anticoagulant principles of Vipera russellii snake venom.

Vipera russellii venom was separated into thirteen fractions by means of DEAE-Sephadex A-50 column chromatography. Fraction III possessed anticoagulant and phospholipase A activities and Fraction XI possessed procoagulant and caseinolytic activities, both were further purified by gel filtration on Sephacryl S-200 column. Purified procoagulant (Component II) was a two-chain protein with molecular weight of 86 000 consisting of A-chain (Mr 66 000) and B-chain (Mr 20 000). It was a glycoprotein containing 7.8% neutral sugar and 715 amino-acid residues. The procoagulant activity was 10-times that of the crude venom. It was an acidic proteinase with isoelectric point of pH 4.2. Upon heat treatment at 60 degrees C, Component II was stable at pH 5.5 and 7.2 for 3 h, but was destroyed completely after 30 min at pH 8.9. It was devoid of esterase or amidase activity. Purified anticoagulant (Component I) was a single peptide chain with molecular weight of 16 000. It was carbohydrate free and contained 136 amino-acid residues. It was a basic protein with an isoelectric point of larger than pH 10. It was a potent phospholipase A with an enzymatic activity of 510 +/- 30 mumol/min per mg using phosphatidylcholine as substrate, and 1 microgram/ml was sufficient to cause 100% hemolysis by the indirect hemolytic method. Upon heat treatment at 90 degrees C, Component I was heat stable at pH 5.5 for more than 3 h, but was destroyed completely after 2 h at pH 7.2 and 8.9. The anticoagulant activity of Component I could be neutralized by platelet factor 3, tissue thromboplastin and cephalin.

Amino Acids↗

PubMed1985

Ammodytoxin A, a highly lethal phospholipase A2 from Vipera ammodytes ammodytes venom.

The amino acid sequence of ammodytoxin A, the most toxic presynaptically active phospholipase A2 isolated from Vipera ammodytes ammodytes venom, was determined. The primary structure was deduced from peptides obtained by Staphylococcus aureus proteinase and trypsin digestion of reduced and carboxymethylated protein and from the automated Edman degradation of the N-terminal part of the non-reduced molecule. According to the sequence, the enzyme classifies to the subgroup IIA of the phospholipase A2 family of enzymes. The location of basic residues believed to be responsible for the toxic activity of presynaptically active phospholipases differs substantially from those in the highly toxic enzymes of other subgroups. Comparison of the sequence with sequences of other snake venom enzymes indicates that the toxic site(s) may not be the same in all subgroups of presynaptically active phospholipases.

Amino Acid Sequence↗

PubMed1992

Purification and amino-acid sequence of a nerve growth factor from the venom of Vipera russelli russelli.

Nerve growth factor (NGF) was purified from the venom of Vipera russelli russelli by Sephadex G-50 gel filtration, S-Sepharose column chromatography and Blue-Sepharose CL-6B column chromatography. The purified NGF was found to be a glycoprotein, whose apparent molecular mass was estimated to be about 17.5 kDa by SDS-PAGE. The amino-acid sequence was determined by a combination of conventional methods. The V. r. russelli NGF was composed of 117 amino-acid residues with one residue, Asn-21, being N-linked glycosylated and the molecular mass of its protein portion was calculated to be 13,280 Da.

Amino Acid Sequence↗

PubMed1995

Effect of ammodytin L from Vipera ammodytes on L-6 cells from rat skeletal muscle.

Ammodytin L (AMDL) is a myotoxic phospholipase-like protein from the venom of Vipera ammodytes with a serine in position 49 instead of an aspartate, therefore this toxin is devoid of phospholipase activity, and the membrane-damaging effect does not involve any step of phospholipase activity. The aim of the present study was to analyze the effect of AMDL on L-6 cells from rat skeletal muscle to investigate its mechanism of action and the role of calcium ions in its muscle-damaging activity. Our data indicate that the effect of ammodytin L is strongly dependent on the degree of cell differentiation. Low doses of myotoxin gave rise to a marked release of creatine kinase in myotubes differentiated from L-6 myoblasts and the presence of calcium ions plays a role in the cytotoxic effect. The presence of EGTA in the incubation buffer reduced by 50% the release of creatine kinase. No membrane damage was observed in myoblasts, but there was a significant increase of intracellular calcium concentration measured with Fura-2. A non-specific membrane effect of AMDL was ruled out using platelets as reference cells: no platelet aggregation pattern and no increase in intracellular calcium were observed.

Animals↗