PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Viperidae”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1991

[Hemolytic activity of venoms from snakes of the genera Bothrop, Lachesis, Crotalus, and Micrurus (Serpentes: Viperidae and Elapidae].

Hemolytic activity of eight Peruvian snake venoms from the families Viperidae and Elapidae (Bothrops atrox, B. pictus, B. hyoprorus, B. bilineatus, B. neuwedii, Lachesis m. muta, Crotalus d. terrificus, Micrurus tschudi), and three Brazilian viperids (B. jararacussu, B. alternatus and C. d. collilineatus) is described. None of the venoms caused direct lysis on washed human erythrocytes. However, all of them caused indirect hemolysis provided that the incubation medium contains an exogenous source of lecithin. Venom of Micrurus tschudi was the most hemolytic (HD50 2.8 ug/ml) while that of B. bilineatus was the least (HD50 681.3 ug/ml). Only six of eleven venoms showed parallel curves of hemolytic activity, and the HD50 varied from 198 to 681 ug/ml and the following decreasing order of hemolytic activity was obtained: L. muta, C. d. terrificus, C. d. collilineatus, B. hyoprorus, B. bilineatus, B. alternatus.

Animals↗
PubMed1991

Structural changes of the periosteocytic area in Vipera aspis (L.) (Ophidia, Viperidae) bone tissue in various physiological conditions.

Microradiographs of ribs and vertebrae of the snake Vipera aspis, over an annual cycle, show a significant enlargement of the osteocytic lacunae in the winter months and, for the breeding females, during the period of embryo development. This enlargement is due to resorption of bone substance (periosteocytic osteolysis). The objection that such morphological findings could as well be explained by the formation of new, larger osteocytes derived from recent osteoblasts does not apply to the present animal model. No internal bone remodelling occurs during the annual seasonal cycle and therefore no new osteoblasts would have differentiated to osteocytes in the interior of the bone. In the vertebrae, an additional process is indicated as an area of decreased mineral density, termed demineralization halo, around the periosteocytic lacunae. An electron microscopy study suggests that this process of demineralization is not the first stage of periosteocytic resorption, but an additional process of demineralization. Thus, both osteolysis and demineralization halos in the perilacunar osteocytic region of the bone tissue represent reversible biological processes mediated by the osteocytes.

Animals↗
PubMed1992

Characterization of a proteolytic enzyme from Lachesis muta venom (Serpentes: Viperidae).

A proteolytic enzyme from L. muta stenophrys was isolated by gel filtration on Bio Gel P-100 followed by FPLC on MONO S column. The enzyme exhibited proteolytic activity toward casein, hemoglobin and fibrinogen with a pH optimum around 10. The activity was inhibited by EDTA while trypsin inhibitors were not inhibitory. It is a glycoprotein, Mr 14 kDa with a high content of Asp, Glu, and Leu residues and a low content of Cys and Trp. The protease is devoid of myotoxic, hemorrhagic, esterolytic and amidolytic activities. It lyses the alfa and beta chains of human fibrinogen and releases kinin from L.M.W. kininogen. No release of histamine was observed upon incubation with mast cells.

Animals↗
PubMed1990

[The serum of newborn Clelia clelia (Serpentes: Colubridae) neutralizes the hemorrhagic action of Brothrops asper venom (Serpentes: Viperidae)].

The ability of serum from nine newborn specimens of Clelia clelia (Colubridae) to neutralize hemorrhagic action of Bothrops asper venom was tested. All serum samples neutralized completely the hemorrhagic effect of the venom in mice. This finding shows that the neutralizing ability of C. clelia serum towards the hemorrhagic activity of B. asper venom is innate.

Animals↗
PubMed1991

Immunochemical cross-reactivity of two phospholipase A2 neurotoxins, agkistrodotoxin and crotoxin.

Polyclonal rabbit antisera were raised against the phospholipase A2 neurotoxin agkistrodotoxin (AGTX) from Agkistrodon blomhoffii brevicaudus venom and against the phospholipase A2 subunit (component-B, CB) of crotoxin from Crotalus durissus terrificus venom. Anti-AGTX antibodies cross-reacted strongly with crotoxin and crotoxin-like molecules and more weakly with other phospholipases A2 from the venoms of Viperidae and Crotalidae. On the other hand, anti-CB antibodies cross-reacted with AGTX, and also recognized ammodytoxin A and the phospholipase A2 from Vipera berus venom, but not other phospholipases A2 from Crotalidae and Viperidae. Anti-AGTX and anti-CB antibodies were able to inhibit the phospholipase A2 activity and to neutralize the lethal potency of the homologous and heterologous toxins (AGTX or crotoxin). Immunoaffinity chromatography columns were used to isolate anti-AGTX antibodies which recognized CB (91% of the total anti-AGTX antibodies), and anti-CB antibodies which recognized AGTX (52% of the total anti-CB antibodies). Immunochemical investigations performed with each type of antibody indicated that the majority of AGTX antigenic determinants are present on crotoxin component-B and on phospholipases A2 from Viperidae venoms, and that some of these determinants are involved in the neutralization of lethal potency and in the inhibition of enzymatic activity of AGTX and crotoxin.

Animals↗
PubMed1991

Purification and properties of an antivenom factor from the plasma of the South American rattlesnake (Crotalus durissus terrificus).

The lethal toxicity of Crotalus durissus terrificus (Crotalinae, Viperidae) can be attributed mainly to the presence of a neurotoxic protein, crotoxin, which also shows phospholipase A2 activity. It has been previously demonstrated that both lethal and phospholipase A2 activities of crotoxin can be neutralized by an alpha 1-globulin factor that is present in the homologous blood. Crotalus durissus terrificus plasma also renders some degree of protection to mice against the lethal toxicity of heterologous venoms from snakes of the genus Bothrops (Crotalinae, Viperidae), but not of the genus Micrurus (Elapinae, Elapidae). An anti-toxic factor was purified to homogeneity from C.d. terrificus plasma after three chromatographic steps (DEAE-Sephacel anion exchange, CM-Sepharose cation exchange and Pro-RPC reverse phase chromatography); it is named CNF for Crotalus neutralizing factor. The purification process was accompanied by polyacrylamide gel electrophoresis in the presence of SDS and by measurements of phospholipase A2 inhibition. After the first two purification steps, an 86-fold increase of the inhibitory activity of CNF was observed; however, the third step caused an apparent inactivation of the factor. The inactive CNF was shown to correspond to the previously active plasma material and to be homogeneous on electrophoresis, immunoelectrophoresis and partial amino-terminal sequence. The mol. wt of CNF was estimated as 23,600 by SDS-PAGE.

Animals↗
PubMed1992

1991 Sir Henry Wellcome Medal and Prize recipient. Medical studies of the poisonous land and sea snakes found in and around Saudi Arabia.

Studies were carried out to determine the comparative toxicity and pathophysiology of 13 of the more poisonous snakes indigenous to Saudi Arabia. Included were four snakes from the Viperidae family, six from the Elapidae family, and three representative sea snakes from the family Hydrophidae. Anesthetized adult beagle dogs and anesthetized monkeys were used in the study. Vital physiological functions were continuously recorded as were changes in the blood coagulation system and any tissue damage produced by the venom at the site of envenomation. For the intravenous administration of the venom, lyophilized venom was obtained by "milking" each of the live specimens used in the study. Actual envenomation was accomplished by grasping the poisonous reptile and allowing the snake to strike the shaved exposed gluteal muscle of the anesthetized animal. Venom from the snakes of the family Viperidae produced death in an average of 3 hours. The average lethal dose was 1.13 mg/kg. Depression of first and second stage clotting factors was observed with these venoms as well as a decrease in fibrinogen levels and in platelet counts. Findings suggestive of intravascular coagulation were also observed with moderate hemolysis of the formed elements. Some local hemorrhage was seen at the site of envenomation. Venom from the Elapidae family of snakes produced death at an average of 1.7 hours. The average lethal dose was 0.70 mg/kg. Death appeared to be primarily due to respiratory paralysis following blockade at the neuromuscular junction. Only moderate hemolysis was seen with these venoms. No intravascular coagulation or tissue damage was seen. The venom of the family Hydrophidae consistently produced death in less than 30 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The kallikrein, kininase and related peptides activities in central Asian snake venoms.

The quantitative content estimation of kininogenases, kininases and related peptides have been made for Central Asian snake venoms: V. lebetina turanica and E. multisquamatus (gen. Vipera and Echis, fam. Viperidae), Ag. halys halys (gen. Agkistrodon, fam. Crotalidae) and N. oxiana (gen. Naja, fam Elapidae). It has been demonstrated, that all venoms investigated cause the contractile effect, when acting on isolated smooth muscle preparations. Kinin-like contractile activity was found in the low molecular weight fraction of the cobra venom. This action has the prolonged character as compared with bradykinin, but apart from it, results in the inactivation of the rat uterus because of cytotoxic components presence. The specific bradykinin-potentiating effect of the low molecular weight fraction of the E. multisquamatus venom has been discovered. It has been found, that the effect is connected with inhibition of the kininase II (angiotensin I converting enzyme, ACE). Two peptide inhibitors was isolated and characterized from this fraction.

Amino Acid Sequence↗
PubMed1991

Conservative and variable regions of homologous snake phospholipases A2 sequences: prediction of the taxon-specific peptides structure.

Homologous amino acid sequences of phospholipases A2 (PLA2) of snakes belonging to the families Elapidae, Viperidae, and Colubridae were considered in order to study the conservative and variable regions location. The PLA2 sequences were divided into two groups (taxons) according to the phylogenetic tree reconstructed from the pair similarity matrix. Results of the intergroup comparison were plotted to facilitate the identification of significant conservative and variable regions. It was shown that the results of the comparison between two phylogenetic groups of snake PLA2 did not much depend on the number of each group representatives and did not markedly change if one of the groups was represented by the single sequence. The knowledge of the number and location of conservative and variable regions and their dependence on the phylogenetic relations between compared taxa may be used to predict a synthetic peptide structure to obtain specific antibodies against PLA2 of one of these taxons. Such prediction is possible if there is a specific region conservative for one taxon but variable for two of them.

Amino Acid Sequence↗
PubMed1976

A phospholipase A2 with anticoagulant activity. II. Inhibition of the phospholiped activity in coagulation.

An anticoagulant factor with phospholipase A2 activity has been isolated from Vipera berus venom. Phospholipase activity was studied on platelet phospholipid and on brain cephalin. The venom factor showed a potent anticoagulant activity: 1 mug impaired the clotting of 1 ml of citrated recalcified platelet-poor plasma. The anticoagulant inhibited clotting by antagonism to phospholipid. The antagonism constant (Kan = 6.8-10(-9) M) demonstrated the high affinity of the inhibitor for phospholipid. As with other phospholipases A2, the venom factor was thermoresistant but very sensitive to photo-oxidation. Both activities (anticoagulant activity and phospholipase activity) were not markedly dissociated by either denaturation or neutralization processes. Slightly different curves of photo-oxidative inactivation of both activities suggested the presence, on the molecule, of two very close sites responsible for phospholipase and anticoagulant activities. The inhibitor effect on coagulation was independent of the hydrolysis process. In fact, lysoderivatives and fatty acids, resulting from complete hydrolysis with the venom factor, were as active as the native phospholipids. Moreover phospholipase A2 from other viperidae venom, which did not have anticoagulant activity, produced similarly active lysoderivatives. This showed that the cleavage of the beta-acyl bond does not interfere with the activity of phospholipid. A possible mechanism of clotting inhibition by the venom factor was proposed. Owing to its high affinity for phospholipid, the inhibitor would complex phospholipid at its protein binding site impairing the normal arrangement of coagulation protein factors and, consequently, their activation. The positive charges of the inhibitor (pI = 9.2) could bind with phosphoryl or carboxyl groups of phospholipid, making them unavailable for protein binding. The complex formation involves a loss of dissociating capacity of the enzyme towards its substrate. This required an additional interaction of the inhibitor with a coagulation protein factor. The inhibitor could be removed from the complex by specific antibodies, permitting recovery of normal phospholipid-protein interaction. The role of calcium in the complex has not yet been elucidated. This venom factor affords a useful tool for investigating the phospholipid-clotting protein interaction.

Anticoagulants↗
PubMed1990

Preparation of antibodies to king cobra (Ophiophagus hannah) venom hemorrhagin and investigation of their cross-reactivity.

Hannahtoxin, the major hemorrhagin purified from king cobra (Ophiophagus hannah) venom, elicits hemorrhages in rabbits but not in mice. Two antisera against hannahtoxin were prepared: one raised against purified hannahtoxin, while the other was raised against glutaraldehyde cross-linked and detoxified hannahtoxin. The antisera were refined by pepsin digestion and ammonium sulfate precipitation. They are of approximately equal potency in their ability to neutralize the hemorrhagic activity of king cobra venom in rabbits. The antisera did not form a precipitin line with venom of snakes of the Viperidae family nor neutralize hemorrhages elicited in mice by any of these venoms. However, when the hemorrhagic activity was assayed in rabbits, both antisera were able to abolish the hemorrhages elicited by all of the venoms tested. These results suggest that hannahtoxin displays few epitopes in common with hemorrhagins of viperid venoms, except those involved in the neutralization of hemorrhagic activity in rabbits. The epitopes of viperid venom hemorrhagins involved in the neutralization reaction in rabbits are different from those in mice.

Animals↗
PubMed1992

The use of enzyme-linked immunosorbent assay for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom and venom antibodies.

The specificity and sensitivity of an indirect and two (an 'ordinary' and a 'rapid') double sandwich enzyme-linked immunosorbent assay (ELISA) procedures for the quantitation of Calloselasma rhodostoma (Malayan pit viper) venom were examined. The three assays were equally sensitive and the accuracy of the assays was not substantially affected by individual variation in the venom composition. The specificity of the assays was examined against 26 venoms from snakes of the families Viperidae and Elapidae. While the double sandwich ELISA procedures were sufficiently specific to be used in the clinical immunodiagnosis of C. rhodostoma bite in Malaysia, the indirect ELISA procedure exhibited extensive cross-reactivity with other Malaysian pit viper venoms. Attempts were made to improve the specificity of the indirect ELISA procedure for the quantitation of C. rhodostoma venom. A 'low ELISA cross-reactivity' venom fraction (termed VF52) was isolated from C. rhodostoma venom by repeated Sephadex G-100 gel filtration chromatography. The indirect ELISA procedure using antibodies to VF52 as immunoreagent showed an improvement in specificity. The use of the indirect ELISA procedure for the detection of C. rhodostoma antibodies was also examined and the results show that the assay was sufficiently specific to be used for retrospective diagnosis of C. rhodostoma bite in Malaysia, in particular when VF52 was used as the coating antigen.

Antibody Specificity↗
PubMed1990

Elegantin and albolabrin purified peptides from viper venoms: homologies with the RGDS domain of fibrinogen and von Willebrand factor.

The RGD-containing peptides isolated from the venoms of the Viperidae constitute a new class of small cysteine-rich peptides of variable amino acid composition and biological activity (Huang, T.-F., et al. (1987) J. Biol. Chem. 262, 16157-16163; Gan, Z.R., et al. (1988) J. Biol. Chem 263, 19827-19832; Huang, T.-F., et al. (1989) Biochemistry 28, 661-668), which it is proposed by Gould et al. (unpublished data) that we call 'disintegrins'. These peptides bind to the glycoprotein IIb-IIIa receptor on the platelet surface and inhibit aggregation induced by ADP, thrombin, platelet-activating factor and collagen. These peptides are also potent inhibitors of cell adhesion to fibrinogen (Knudsen, K.M., et al. (1988) Exp. Cell Res. 179, 42-49). We report the isolation of two further RGD-peptides from the venoms of Trimeserusus elegans and Trimeserusus albolabris, purified to homogeneity with high yield by a novel, rapid reverse-phase HPLC method. The primary structures of these two peptides were determined to be single polypeptide chains of 73 amino acids. Albolabrin differed from trigramin by eight residues whilst elegantin differed by 22 residues. The molecular mass of albolabrin calculated on the basis of amino acid sequence was 7574 Da and the pI similarly calculated was 4.27. The molecular mass of elegantin was calculated to be 7806 Da and the theoretical pI to be 4.69. RGD is maintained in the same position (51-53 AA) and all 12 cysteines are identical. Our data suggest that the presence of RGD, the conserved secondary and tertiary structure, are essential for the expression of biological activity by these peptides. Both peptides inhibited ADP-induced platelet aggregation. Extended homologies around the RGDS sequences in human von Willebrand Factor and bovine fibrinogen were found with both peptides.

Amino Acid Sequence↗
PubMed1992

Electrophoretic analysis of snake venoms.

Electrophoretic analyses were conducted on snake venoms from 21 species representing Elapidae, Crotalidae and Viperidae. Denatured and native venoms were analyzed by polyacrylamide gel electrophoretic (PAGE) methods with sodium dodecyl sulfate (SDS) and without SDS. Both SDS-PAGE and PAGE profiles of venoms from different snake species indicate that some proteins and polypeptide components of these venoms have common electrophoretic characteristics suggesting a genetic relationship. Conversely, the electropherograms also showed the characteristic protein and polypeptide profiles that could differentiate one snake species from another. Therefore, both SDS-PAGE and PAGE profiles suggest that proteins and polypeptides with similar characteristics abound among subspecies or related species, although each venom has a unique profile that differentiates one species from the other.

Animals↗
PubMed1992

Mambin, a potent glycoprotein IIb-IIIa antagonist and platelet aggregation inhibitor structurally related to the short neurotoxins.

The purification, complete amino acid sequence, functional activity, and structural modeling are described for mambin, a platelet glycoprotein GP IIb-IIIa antagonist and potent inhibitor of platelet aggregation from the venom of the Elapidae snake Dendroaspis jamesonii (Jameson's mamba). Mambin is 59 residues in length and contains four disulfide linkages and an RGD amino acid sequence found in protein ligands that bind to GP IIb-IIIa. Mambin inhibits ADP-induced platelet aggregation (IC50 = 172 +/- 22 nM) and inhibits the binding of purified platelet fibrinogen receptor GP IIb-IIIa to immobilized fibrinogen (IC50 = 3.1 +/- 0.8 nM). Mambin has very little sequence similarity to the Viperidae family of platelet aggregation inhibitors, except for the RGD-containing region in the protein. However, mambin does have ca. 47% similarity to the short-chain postsynaptic neurotoxins found in other Elapidae venoms, which do not contain the RGD sequence and do not act as GP IIb-IIIa antagonists. On the basis of its circular dichroism spectrum, mambin has a beta-sheet structure characteristic of the neurotoxins. Molecular modeling of the mambin sequence onto the erabutoxin b structure predicts a very similar structure within the entire protein except for the loop containing the RGD sequence. Mambin may therefore represent a genetic hybrid of neurotoxic and hemotoxic proteins found in snake venoms.

Amino Acid Sequence↗