| proteolytic digestion of non-collagenous basement membrane proteins by the hemorrhagic metalloproteinase ht-e from crotalus atrox venom. | hemorrhagic toxin e (ht-e), a metalloproteinase isolated from the venom of the western diamondback rattlesnake crotalus atrox, digests laminin and nidogen, both in their isolated forms and when present in a purified soluble complex. the only common site of cleavage by ht-e of isolated nidogen and nidogen when complexed with laminin is at amino acid residue 336 in the amino terminal domain. additionally, nidogen in complex with laminin is also cleaved at sites 322, 351 and 840 as determined by se ... | 1991 | 1801753 |
| antihemorrhagic factors from the blood serum of the western diamondback rattlesnake crotalus atrox. | several antihemorrhagic factors isolated from c. atrox serum are glycoproteins with mol. wt ranging from 65,000 to 80,000. the antihemorrhagic activity of these factors was stable at a ph range of 1.3-11.5 and at temperatures up to 85 degrees c, for 30 min. the isolated antihemorrhagins also neutralized the proteolytic activity of c. atrox venom, as tested with azocollagen and gelatin, and formed a complex with hemorrhagic toxin e isolated from the same venom. the neutralization capacity of the ... | 1991 | 1656547 |
| primary structure of a hemorrhagic metalloproteinase, ht-2, isolated from the venom of crotalus ruber ruber. | crotalidae and viperidae snake venoms contains several kinds of metalloproteinases which cause localized hemorrhage by direct action on blood vessel walls. we report here the entire amino acid sequence and the disulfide bridge locations of ht-2, one of the hemorrhagic toxins isolated from the venom of crotalus ruber ruber (red rattlesnake). the non-reduced protein was first cleaved at methionine residues to provide a set of 8 fragments, which covered the entire sequence of ht-2. the disulfide br ... | 1990 | 2081731 |
| the complete amino acid sequence of the high molecular mass hemorrhagic protein hr1b isolated from the venom of trimeresurus flavoviridis. | hemorrhage is a common occurrence in a victim bitten by crotalid and viperid snakes, and hemorrhagic components in these various venoms have been isolated and characterized. previously, we have shown that a low molecular weight hemorrhagic protein (hr2a, 202 amino acid residues) isolated from the venom of trimeresurus flavoviridis is a member of a new subfamily of metalloproteinases. we now report the complete amino acid sequence of a high molecular mass hemorrhagic protein isolated from the sam ... | 1990 | 2398046 |
| glycerol monoethers in the scent gland secretions of the western diamondback rattlesnake (crotalus atrox; serpentes, crotalinae). | 1-o-monoalkylglycerols with c12 to c20 chains were identified in the scent gland secretions of the western diamondback rattlesnake (crotalus atrox). this is the first documentation of these compounds in the skin secretions of a reptile. | 1990 | 2373208 |
| hydrolysis of supported pyrenephospholipid monolayers by phospholipase a2. | hydrolysis by pancreatic and snake venom (crotalus atrox) phospholipase a2 of fluorescent monolayers of pyrene-labelled phosphatidylglycerol on solid support was studied. we used a fluorescence microscope equipped with video camera, video recorder and an image analyzer to monitor changes in fluorescence. decrease in pyrene excimer emission was evident when pyrene phosphatidylglycerol monolayers transferred onto quartz glass slides (at a surface pressure of 15 mn m-1) were subjected to enzymatic ... | 1990 | 2208445 |
| identification of the cleavage sites by a hemorrhagic metalloproteinase in type iv collagen. | type iv collagen, solubilized from engelbreth-holm-swarm (ehs) tumor basement membranes is digested by a hemorrhagic metalloproteinase, ht-e, isolated from the crude venom of the western diamondback rattlesnake, crotalus atrox. the major proteolytic products have mr 141,000, 132,000, 87,000, 71,000, 33,000 and approximately 18,000 as estimated by sds-gel electrophoresis of pepsinized type iv collagen fragments. sequence analysis of the digestion products reveal that the mr 141,000, 71,000 and ap ... | 1990 | 2374521 |
| investigation of an active site histidine-aspartate couple in trimeresurus flavoviridis phospholipase a2. | when trimeresurus flavoviridis phospholipase a2 was reacted with methyl p-nitrobenzenesulfonate, its activity decreased following first-order kinetics. the ph dependence of the rate constants of inactivation showed that his-48 with an apparent pka of 6.5 controls the reaction. in the ph region below 6.5, n1-methylhistidine was predominantly formed. on the other hand, n1,n3-dimethylhistidine was almost exclusively produced in the ph region above 6.5. no n3-methylhistidine was detected at any ph t ... | 1989 | 2628422 |
| degradation of extracellular matrix proteins by hemorrhagic metalloproteinases. | the proteolytic activity of four hemorrhagic metalloproteinases (ht-a, c, d, and e) isolated from the venom of the western diamondback rattlesnake (crotalus atrox) was investigated using isolated extracellular matrix (ecm) proteins. we determined that all of the proteinases are capable of cleaving fibronectin, laminin, type iv collagen, nidogen (entactin), and gelatins. however, none of the proteinases were proteolytic against the interstitial collagen types i and iii or type v collagen. with al ... | 1989 | 2817904 |
| purification and biochemical characterization of atroxase, a nonhemorrhagic fibrinolytic protease from western diamondback rattlesnake venom. | crotalus atrox venom contains a variety of proteases which render fibrinogen incoagulable and solubilize fibrin. one of these proteases was purified by using ion-exchange and gel permeation liquid chromatography. the protease, called atroxase, consists of a single nonglycosylated polypeptide chain with a molecular weight of 23,500 and an isoelectric point of ph 9.6. amino acid analysis indicates atroxase to contain 206 residues with no sulfhydryl groups. metal analysis found zinc and potassium a ... | 1988 | 3167016 |
| proton nmr resonance assignments and surface accessibility of tryptophan residues of a dimeric phospholipase a2 from trimeresurus flavoviridis. | proton nmr spectra of a dimeric phospholipase a2 from trimeresurus flavoviridis have been recorded. n-1 proton resonances of the tryptophan indole rings have been detected and assigned to specific positions, trp-3/trp-30, trp-68 and trp-108, by comparing the spectra of the enzyme derivatives with tryptophans oxidized to differing extents. photo-cidnp experiments have revealed that trp-68 and trp-108 are exposed while trp-3 and trp-30 are buried in the molecule. this is consistent with the x-ray ... | 1988 | 3350151 |
| classification of myonecrosis induced by snake venoms: venoms from the prairie rattlesnake (crotalus viridis viridis), western diamondback rattlesnake (crotalus atrox) and the indian cobra (naja naja naja). | the pathogenesis of myonecrosis induced by three different snake venoms was studied by light microscopic examination of skeletal muscle tissue taken at time periods ranging from 0.25 hr to 4 weeks after an intramuscular injection of the venom into mice. it was possible to identify different types of myonecrosis based on the abnormal morphologic states of the damaged cells. the types of myonecrosis observed correlated with the types of components present in the venom injected. venoms containing d ... | 1988 | 3188052 |
| characterization of two hemorrhagic zinc proteinases, toxin c and toxin d, from western diamondback rattlesnake (crotalus atrox) venom. | two hemorrhagic proteinases from crotalus atrox venom, hemorrhagic toxin c (ht-c) and hemorrhagic toxin d (ht-d), were characterized and compared to one another. the two toxins are zinc metalloproteinases which both have molecular weights of 24,000. their isoelectric points are slightly acidic, ht-c being the more basic of the two with an isoelectric point of 6.2, whereas ht-d has an isoelectric point of 6.1. only minor differences were found in the amino acid compositions of the two toxins. the ... | 1987 | 3101740 |
| self-association and active enzyme forms of naja naja naja and crotalus atrox phospholipase a2 studied by analytical ultracentrifugation. | the dimerization of phospholipase a2 (plpa2) from naja naja naja (pakistani cobra) and crotalus atrox (western diamondback rattlesnake) has been studied from ph 2.5 to 11 at 20 degrees c in 1 mm cacl2, 0.21 m ionic strength. for the c. atrox enzyme, it was found necessary to use a combination of sedimentation equilibrium and fluorescence yield data to analyze the association. sedimentation equilibrium in the analytical ultracentrifuge sufficed for the study of the n. naja plpa2. in the region of ... | 1986 | 3801457 |
| identification of the tryptophan residue located in the calcium binding site of trimeresurus flavoviridis phospholipase a2. | when phospholipase a2 from the venom of trimeresurus flavoviridis (the habu snake) was oxidized with n-bromosuccinimide at ph 4.0, its activity decreased linearly with increase in the extent of oxidation of tryptophan residues. oxidation of two of the four tryptophan residues caused an apparent loss of activity. the accessibilities of the tryptophan residues were analyzed with differently oxidized phospholipase a2 preparations and were determined to be in the following order: trp-3 approximately ... | 1986 | 3818568 |
| ability of polyvalent (crotalidae) antivenom to neutralize local myonecrosis induced by crotalus atrox venom. | wyeth's polyvalent (crotalidae) antivenom was tested in mice for its ability to neutralize local myonecrosis induced by crude crotalus atrox venom. a light microscopic assay was used to quantitate myonecrosis after i.m. injection of antivenom-venom mixtures. the results indicate that antivenom neutralizes the local myotoxicity of up to 15 micrograms venom per g body weight of mice. this neutralization is significantly better than that previously reported for crotalus viridis viridis venom. | 1986 | 3705097 |
| fatal rattlesnake envenomation in arizona: 1969-1984. | case histories of the last nine fatalities (1969-1984), in which the cause of death on the state of arizona certificate of death was snakebite, were reviewed. six males and three females ranged in age from 2 to 77 years, and were bitten between 0800-2100 hours from april to september. bites in three adult males were "illegitimate" and of these, two were by captive mojave rattlesnakes, crotalus s. scutulatus. the latter two victims had been bitten previously and remained at home, refusing treatme ... | 1986 | 3701904 |
| separation of crotalus atrox (western diamondback rattlesnake) alpha-proteinase from serine proteinase and hemorrhagic factor activities. | a method for obtaining crotalus atrox alpha-proteinase (ec 3.4.24.1) in a pure form has been developed. fractionation of the crude venom on deae-sepharose, followed by gel filtration on bio-gel p-150 and chromatography on cm-sepharose, yielded an alpha-proteinase preparation which showed a single band on disc and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had an activity on casein approximately twice that previously reported. the enzyme is a nonglycosylated single-chain polype ... | 1985 | 3913334 |
| isolation and characterization of hemorrhagic toxin g from the venom of crotalus atrox (western diamondback rattlesnake). | hemorrhagic toxin g (ht-g) was isolated from crotalus atrox (western diamondback rattlesnake) venom using a five-step purification procedure to obtain approximately equal to 5.9 mg of purified ht-g from 2.0 g of crude venom. the purified toxin was homogeneous by disc electrophoresis on polyacrylamide gel at ph 8.3 and 4.3, and by isoelectric focusing. ht-g possessed lethal, hemorrhagic and proteolytic activities. these activities of toxin were inhibited by ethylenediamine-tetraacetic acid (edta) ... | 1985 | 3834802 |
| the refined crystal structure of dimeric phospholipase a2 at 2.5 a. access to a shielded catalytic center. | the 2.5-a crystal structure of the calcium-free form of the dimeric venom phospholipase a2 from the western diamondback rattlesnake crotalus atrox, has been refined to an r-factor of 17.8% (i greater than 2 sigma) and acceptable stereochemistry. the molecule is a nearly perfect 2-fold symmetric dimer in which most of the catalytic residues of both subunits face an internal cavity. the restricted access to the putative catalytic sites is especially puzzling as the optimal substrates for this and ... | 1985 | 4019493 |
| rattlesnake bite of glans penis. | the envenomation of the glans penis by a western diamondback rattlesnake (crotalus atrox) is presented. effects of envenomation, first aid, and hospital management are briefly reviewed. | 1985 | 4012978 |
| specificity of hemorrhagic proteinase from crotalus atrox (western diamondback rattlesnake) venom. | hemorrhagic proteinase, htb, isolated from crotalus atrox (western diamondback rattlesnake) venom was studied for its specificity. htb showed fibrinogenase activity, hydrolyzing the a alpha chain of fibrinogen first, followed by the cleavage of the b beta chain. htb is different from thrombin and did not produce a fibrin clot. the degradation products of fibrinogen were found to be different, indicating that the cleavage sites in the a alpha and b beta chains are different from those of thrombin ... | 1985 | 3888273 |
| a new peptide from crotalus atrox snake venom. | the presence of new hypotensive peptides, possibly not related to ace inhibition, has been investigated on 66 snake venoms from crotalid, viperid and elapid families. only the venom of crotalus atrox showed a substantial amount of a new decapeptide, called pol-236, with the following aminoacid sequence: pyr-leu-trp-pro-arg-pro-gln-ile-pro-pro. pharmacological assays performed on the synthesized peptide revealed effects on blood pressure, probably derived from vascular and cardiac interferences. | 1985 | 3831966 |
| isolation and biochemical characterization of hemorrhagic toxin f from the venom of crotalus atrox (western diamondback rattlesnake). | hemorrhagic toxin f (ht-f) was isolated from crotalus atrox (western diamondback rattlesnake) venom by a five-step purification procedure. homogeneity was established by the formation of a single band in acrylamide gel electrophoresis, isoelectric focusing, and sodium dodecyl sulfate (sds)-electrophoresis. ht-f has a molecular weight of 64,000 and contains 572 amino acid residues. it contains 1 mol of zinc per mol of protein. zinc is essential for both hemorrhagic and proteolytic activities. ht- ... | 1984 | 6375570 |
| inhibition of epithelial chloride channels by a semi-purified fraction of crotalus atrox venom. | rattlesnake venom has a strong effect on the ionic permeability of plasma membranes. rattlesnake venom and one of its semipurified fractions (cav-c2) has been implicated in affecting both sodium and chloride transfer across epithelia. the mechanism of cav-c2 action on epithelia, however, is still open to question. aplysia californica intestine has been shown to contain both chloride conductive channels and sodium dependent chloride uptake mechanisms in the mucosal membrane of its enterocytes whi ... | 1984 | 6320211 |
| proteolytic specificity and cobalt exchange of hemorrhagic toxin e, a zinc protease isolated from the venom of the western diamondback rattlesnake (crotalus atrox). | | 1983 | 6351911 |
| isolation and characterization of fibrinogenase from western diamondback rattlesnake venom and its comparison to the thrombin-like enzyme, crotalase. | a new type of fibrinogenase was isolated from the venom of the western diamondback rattlesnake (crotalus atrox). unlike thrombin, the newly isolated fibrinogenase did not cause formation of a fibrin clot. various properties of the fibrinogenase we isolated were compared with crotalase isolated from the venom of c. adamanteus. it was found that fibrinogenase has considerable similarity to crotalase isolated by markland and damus in 1971. crotalase is a thrombin-like enzyme and produces a fibrin c ... | 1983 | 6362974 |
| an iron-dependent 5'-nucleotide phosphoribohydrolase activity in the venom of crotalus atrox and its effect upon the determination of mammalian ribonucleotide reductase. | there is an iron-dependent activity in the venom of crotalus atrox which appears to hydrolyze the n-glycosidic sugar-base bond of pyrimidine and purine nucleotides. maximal activation of this activity occurred at 1.0 mmol/l and 0.8 mmol/l fecl3 for cytidine diphosphate (cdp) and adp substrates, respectively. the release of free base affects the background values of control experiments carried out during nucleotide-labelled assays of ribonucleotide reductase which require the conversion of nucleo ... | 1983 | 6307681 |
| western diamondback rattlesnake (crotalus atrox) poisoning. | | 1982 | 7079204 |
| crotalus atrox phospholipase a2. amino acid sequence and studies on the function of the nh2-terminal region. | | 1982 | 7061414 |
| purification of three arginine esterases from the venom of the western diamondback rattlesnake (crotalus atrox). | three acidic arginine esterases have been isolated from the venom of the western diamondback rattlesnake (crotalus atrox). these components demonstrated marked differences in ionic characteristics, as noted by kcl gradient elution from a deae-sephadex a-50 column. molecular weights, as determined from gel permeation chromatography, were estimated at 25,100 (fraction d), 24,000 (b); and 22,900 (f) for the three separate enzymes. the two larger enzymes (b and d) exhibited similar activities toward ... | 1982 | 6819657 |
| isolation and identification of a collagenolytic enzyme from the venom of the western diamondback rattlesnake (crotalus atrox). | a collagenolytic enzyme, with a molecular weight of 58,000 daltons and isoelectric point of 5.1, was isolated and purified from the venom of the rattlesnake crotalus atrox by sephadex g-100 gel filtration followed by chromatography on deae-bio-gel a. the enzyme released alpha-chains from beta-chains of the native collagen and cleaved in the helical region similar to other animal collagenases. the enzyme also hydrolyzed the pz-peptide, however, it did not hydrolyze synthetic substrates for serine ... | 1982 | 6285554 |
| photoaffinity labeling of crotalus atrox phospholipase a2 by a substrate analogue. | a photolabile analogue of phosphatidylethanolamine (photolabile pe analogue), 1,2-di-o-hexylglycero-3-(ethyl diazomalonamidoethyl phosphate), was synthesized in nonisotopic and 14c-radiolabeled form and in both the l configuration (that of the naturally occurring phospholipids) and the racemic form. when the unlabeled racemic compound was photolyzed in the presence of phospholipase a2 of crotalus atrox, extensive enzyme inactivation was observed. the rate of inactivation was stimulated by ca2+ a ... | 1981 | 7470471 |
| heterogeneous catalysis by phospholipase a2: mechanism of hydrolysis of gel phase phosphatidylcholine. | hydrolysis of gel phase dipalmitoylphosphatidylcholine (dppc) at 37 degrees c catalysed by crotalus atrox phospholipase a2 (pla) is described extremely well by the "path 1" kinetic mechanism of tinker and wei (1979) (can. j. biochem. 57, 97-106), if reversible adsorption is allowed as a side reaction. progress curves show an initial rapid phase, the initial velocity being a michaelis-menten function dependent on the catalytic properties of the enzyme (kcat approximately equal to 9200 min-1, km a ... | 1980 | 7459686 |
| fibrinolytic enzyme(s) in western diamondback rattlesnake (crotalus atrox) venom. | | 1980 | 7394818 |
| effect of a semi-purified fraction of crotalus atrox (western diamondback rattlesnake) venom on chloride transport across the frog skin. | | 1980 | 6971502 |
| heterogeneous catalysis by phospholipase a2: formulation of a kinetic description of surface effects. | the kinetics of hydrolysis of aqueous dispersion of long-chain, saturated phosphatidylcholines (pc) catalysed by crotalus atrox phospholipase a2 (pla) have been analyzed, and a reaction mechanism proposed which takes surface effects into account. pla is proposed to form an enzyme-substrate complex with surface substrate molecules, thereby undergoing a conformational change which exposes sites that interact with the lipid surface. after a hydrolytic event, the enzyme can either desorb from the su ... | 1979 | 427633 |
| hemorrhagic toxins from rattlesnake (crotalus atrox) venom. pathogenesis of hemorrhage induced by three purified toxins. | the pathogenesis of hemorrhage induced by three purified components of rattlesnake (crotalus atrox) venom was studied at the light and electron microscopic levels. crude venom was fractionated by anion exchange and gel filtration in four steps. beta-alanine acetate disk gel electrophoresis was used to demonstrate electrophoretic homogeneity. white mice were injected intramuscularly with 0.1 ml of a sublethal dose of hemorrhagic toxin. gross examination revealed extensive hemorrhage 5 minutes aft ... | 1978 | 696805 |
| hemorrhagic toxins from western diamondback rattlesnake (crotalus atrox) venom: isolation and characterization of five toxins and the role of zinc in hemorrhagic toxin e. | five previously unknown hemorrhagic proteins, designated hemorrhagic toxins a,b,c,d, and e, were isolated from the venom of the western diamondback rattlesnake (crotalus atrox). molecular weights of hemorrhagic toxins a-e were determined to be 68 000, 24 000, 24 000, 24 000, and 25 700, respectively, by sodium dodecyl sulfate-phosphate gel electrophoresis using various polyacrylamide gel concentrations. amino acid composition showed a total of 636, 200, 213, 214, and 219 amino acids for hemorrha ... | 1978 | 210790 |
| kinetics of hydrolysis of dispersions of saturated phosphatidylcholines by crotalus atrox phospholipase a2. | dispersions of lamellar phase dipalmitoyl phosphatidylcholine (ddpc) and dimyristoyl phosphatidylcholine (dmpc) in 0.01 m cacl2 were subjected to hydrolysis by phospholipase a2 (ec 3.1.1.4) from crotalus atrox venom. the reaction was followed continuously by titrating the released fatty acids. for hydrolysis of gel phase phosphatides, the steady-state initial velocities were hyperbolic functions of bulk lipid concentrations. at the 'pre-transition' temperature (34 degrees c for dppc, 15 degrees ... | 1978 | 580900 |
| chemical modification of crotalus atrox phospholipase a2 by means of a photolabile phosphatidylethanolamine analog. | | 1978 | 665363 |
| some blood values of the western diamond-back rattlesnake (crotalus atrox) from south texas. | hematologic values of the western diamond-back rattlesnake (crotalus atrox) from south texas were determined by standard techniques. the means of the principal blood measurements were 0.68 +/- 0.20 million erythrocytes/mm3, 31.9 +/- 4.6% hematocrit and 10.0 +/- 1.8 gm% hemoglobin. a comparison of hematologic values of snakes is given. | 1977 | 916141 |
| purification, characterization and analysis of the mechanism of action of four anti-complementary factors in crotalus atrox venom. | | 1977 | 914318 |
| interaction of crotalus atrox venom with serum complement: kinetic analysis. | | 1977 | 914317 |
| the interaction of crotalus atrox phospholipase a2 with calcium ion and 1-anilinonaphthalene-8-sulfonate. | | 1977 | 18264 |
| the action of phospholipase a2 purified from crotalus atrox venom on specifically labelled 2-acyl-1-alk-1'-enyl- and 2-acyl-1-alkyl-sn-glycero-3-phosphorylcholine. | | 1974 | 4416084 |
| effects of fasting on the blood chemistry of the rattlesnake, crotalus atrox. | | 1973 | 4146626 |
| yield of venom obtained from crotalus atrox by electrical stimulation. | | 1972 | 4665361 |
| collagenolytic activity of snake venom: the absence of collagenolytic activity in the trypsin-like enzyme from crotalus atrox venom. | | 1971 | 4332276 |
| observations on the phospholipase a 2 of crotalus atrox. molecular weight and other properties. | | 1971 | 5161032 |
| [further studies on the amino acid sequence of melittin, ii. preferential cleavage of valine-, leucine- and isoleucine bonds by alpha-protease from crotalus atrox venom]. | | 1969 | 4389597 |
| application of crotalus atrox venom alpha-protease for amino acid sequence determination. | | 1967 | 5625443 |
| a method for estimating crotalus atrox venom concentrations. | | 1967 | 6036248 |
| [on the evolution of endopeptidases. ii. properties of the alpha-protease from the venom of crotalus atrox]. | | 1967 | 5586897 |
| electron microscopy of the thymus in two species of snakes, crotalus atrox and lampropeltis getulus. | | 1967 | 6035292 |
| differential resistance of mice at various time levels to the lethality of rattlesnake venom (crotalus atrox). | | 1967 | 6064845 |
| effect of ph, temperature, antivenin and functional group inhibitors on the toxicity and enzymatic activities of crotalus atrox venom. | | 1966 | 4309654 |
| lipid monolayers: action of phospholipase a of crotalus atrox and naja naja venoms on phosphatidyl choline and phosphatidal choline. | the activity of phospholipase a on phosphatidyl choline and phosphatidal choline spread as monolayers on phosphate buffers containing snake venom (crotalus atrox or naja naja) was studied by measuring the fall of surface potential as a function of time, ph, film pressure, temperature, and concentrations of phosphate and venom. at 25 degrees c, ph 7.0, and 0.2 micrograms of venom per ml, optimal activity was observed with both venoms on both substrates at 12 dynes/cm film pressure on 0.04 m phosp ... | 1966 | 5947040 |
| studies on the phospholipase a activity of crotalus atrox venom. | | 1966 | 5938784 |
| [specificity of snake venom proteases (crotalus atrox)]. | | 1965 | 5847962 |
| studies on the phospholipase a activity of crotalus atrox venom.rep no. 630. | | 1965 | 5295166 |
| detoxification of crotalus atrox venom by photooxidation in the presence of methylene blue. rep no. 628. | | 1965 | 5295050 |
| effect of enzymatic functional group inhibitors on the esterases of crotalus atrox venom. rep no. 627. | | 1965 | 5295048 |
| comparative study of anticoagulant and procoagulant properties of 28 snake venoms from families elapidae, viperidae, and purified russell's viper venom-factor x activator (rvv-x). | snake venoms consist of numerous molecules with diverse biological functions used for capturing prey. each component of venom has a specific target, and alters the biological function of its target. once these molecules are identified, characterized, and cloned; they could have medical applications. the activated clotting time (act) and clot rate were used for screening procoagulant and anticoagulant properties of 28 snake venoms. crude venoms from daboia russellii siamensis, bothrops asper, bot ... | 2010 | 20677373 |
| effect of iron and carbon monoxide on fibrinogenase-like degradation of plasmatic coagulation by venoms of four crotalus species. | annually, thousands suffer poisonous snake bite, often from defibrinogenating species. iron and carbon monoxide (co) improve coagulation kinetics by modulation of fibrinogen as demonstrated in various agkistrodon species and crotalus atrox. thus, we sought to determine whether pretreatment of plasma with iron and co could attenuate venom-mediated catalysis of fibrinogen obtained from four common crotalus species with known fibrinogenase activity. human plasma was pretreated with ferric chloride ... | 2017 | 26845427 |
| the deep origin and recent loss of venom toxin genes in rattlesnakes. | the genetic origin of novel traits is a central but challenging puzzle in evolutionary biology. among snakes, phospholipase a2 (pla2)-related toxins have evolved in different lineages to function as potent neurotoxins, myotoxins, or hemotoxins. here, we traced the genomic origin and evolution of pla2 toxins by examining pla2 gene number, organization, and expression in both neurotoxic and non-neurotoxic rattlesnakes. we found that even though most north american rattlesnakes do not produce neuro ... | 2016 | 27641771 |
| neutralization of haemorrhagic activity of viper venoms by 1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-3-oxo-1,3-dihydroisobenzofuran-5-carbonitrile. | viper envenomation undeniably induces brutal local manifestations such as haemorrhage, oedema and necrosis involving massive degradation of extracellular matrix at the bitten region and many a times results in dangerous systemic haemorrhage including pulmonary shock. snake venom metalloproteases (svmps) are being considered to be the primary culprits for the venom-induced haemorrhage. as a consequence, the venom researchers and medical practitioners are in deliberate quest of svmp inhibitors. in ... | 2011 | 21729242 |
| characterization and cdna cloning of dipeptidyl peptidase iv from the venom of gloydius blomhoffi brevicaudus. | dipeptidyl peptidase activity was investigated in snake venoms from gloydius blomhoffi brevicaudus, gloydius halys blomhoffii, trimeresurus flavoviridis and crotalus atrox. the strongest dipeptidyl peptidase iv (dpp iv) activity was found in venom from g. blomhoffi brevicaudus. the substrate specificity, susceptibility to inhibitors, and ph optimum of the partially purified enzyme were similar to those of known dpp ivs from bacteria and eukaryotes. the g. blomhoffi brevicaudus venom gland cdna l ... | 2006 | 16828569 |
| problems with mitigation translocation of herpetofauna. | mitigation translocation of nuisance animals is a commonly used management practice aimed at resolution of human-animal conflict by removal and release of an individual animal. long considered a reasonable undertaking, especially by the general public, it is now known that translocated subjects are negatively affected by the practice. mitigation translocation is typically undertaken with individual adult organisms and has a much lower success rate than the more widely practiced conservation tran ... | 2015 | 25040040 |
| measuring agreement and discord among hemagglutination inhibition assays against different ophidian paramyxovirus strains in the eastern massasauga (sistrurus catenatus catenatus). | at present, the hemagglutination inhibition (hi) assay is the sole commercially available serologic method available to detect exposure to ophidian paramyxovirus (opmv) in snakes. during 2006, 26 eastern massasaugas (sistrurus catenatus catenatus) were collected, and blood was sampled to determine their opmv status. samples from each snake were divided into 3 aliquots and tested by using commercially available hi assays against the 4 opmv isolates used in the 3 laboratories that offer the servic ... | 2008 | 18816997 |
| in silico molecular interaction analysis of ltnf peptide-lt10 with snake venom enzymes. | lethal toxin neutralizing factor (ltnf) isolated from opossum (didephis virginiana) has been shown to exhibit anti-venom and anti-allergic property. the small synthetic peptide- lt10 derived from n-terminal of ltnf also showed this property in vivo. we applied molecular modeling, docking and molecular dynamic (md) simulation techniques to compute the interaction of lt10 peptide with few snake venom enzymes, namely pla2 from naja naja and atrolysin -c from crotalus atrox. our in silico interactio ... | 2014 | 24654849 |
| phospholipase a properties of several snake venom preparations. | the hydrolytic properties of the venoms of seven species of snakes,crotalus adamanteus, ancistrodon contortrix, naja naja, bothrops atrox, ophiophagus hannah, crotalus atrox andvipera russeli, were studied with purified lecithins and mixtures of lecithins of known fatty acid and class composition as substrates.the relative rates of hydrolysis of the fatty acids by the above venoms were studied by analysis of the products of the reaction at intervals during the course of the reaction. of the seve ... | 1966 | 17805626 |
| snakes survive starvation by employing supply- and demand-side economic strategies. | animals vary widely in their abilities to tolerate extended periods of food limitation. although some snakes are known for their unique ability to survive periods of inanition that last up to 2 years, very little is known about the biological mechanisms that allow them to do this. consequently, the present study examined physiological, compositional, and morphological responses to 168 days of starvation among three distantly related snake species (i.e., ball python, python regius; ratsnake, elap ... | 2007 | 17644357 |
| exploring the venom proteome of the western diamondback rattlesnake, crotalus atrox, via snake venomics and combinatorial peptide ligand library approaches. | we report the proteomic characterization of the venom of the medically important north american western diamondback rattlesnake, crotalus atrox, using two complementary approaches: snake venomics (to gain an insight of the overall venom proteome), and two solid-phase combinatorial peptide ligand libraries (cpll), followed by 2d electrophoresis and mass spectrometric characterization of in-gel digested protein bands (to capture and "amplify" low-abundance proteins). the venomics approach revealed ... | 2009 | 19371136 |
| supracategorical fear information revealed by aversively conditioning multiple categories. | fear-generalization is a critical function for survival, in which an organism extracts information from a specific instantiation of a threat (e.g., the western diamondback rattlesnake in my front yard on sunday) and learns to fear - and accordingly respond to - pertinent higher-order information (e.g., snakes live in my yard). previous work investigating fear-conditioning in humans has used functional magnetic resonance imaging (fmri) to demonstrate that activity patterns representing stimuli fr ... | 2020 | 33135598 |
| toxicological profile of medically relevant crotalus species from mexico and their neutralization by a crotalus basiliscus/bothrops asper antivenom. | specimens of the crotalus genus represent a potential snakebite problem in mexico, and despite the great number of species of crotalus present in this country, only a few of them are relevant from a medical point of view. crotalus envenomed patients can present a range of signs and symptoms, depending on the species involved, and their treatment is indistinctly with either of the anti-viperid antivenoms available in the mexican public health system. one of these antivenoms is produced by immuniz ... | 2020 | 32345455 |
| role of scale wettability on rain-harvesting behavior in a desert-dwelling rattlesnake. | during storms in the southwestern united states, several rattlesnake species have been observed drinking rain droplets collected on their dorsal scales. this process often includes coiling and flattening of the snake's body, presumably to enhance water collection. here, we explored this rain-harvesting behavior of the western diamond-backed rattlesnake (crotalus atrox) from the perspective of surface science. specifically, we compared surface wettability and texture, as well as droplet impact an ... | 2019 | 31867507 |
| rattlesnakes must drink: meal consumption does not improve hydration state. | water is critical to survival, yet free-standing water is often rare in deserts and seasonally dry environments. thus, many dry-adapted species utilize either metabolic (that produced from metabolism) or dietary (that found in food) water to meet their hydric needs. it is suspected that desert reptiles can fulfill their hydric needs solely through dietary water intake. however, food consumption does not improve the hydration state of gila monsters (heloderma suspectum), a binge-feeding desert li ... | 2019 | 31135328 |
| mechanisms underpinning the permanent muscle damage induced by snake venom metalloprotease. | snakebite is a major neglected tropical health issue that affects over 5 million people worldwide resulting in around 1.8 million envenomations and 100,000 deaths each year. snakebite envenomation also causes innumerable morbidities, specifically loss of limbs as a result of excessive tissue/muscle damage. snake venom metalloproteases (svmps) are a predominant component of viper venoms, and are involved in the degradation of basement membrane proteins (particularly collagen) surrounding the tiss ... | 2019 | 30695027 |
| the neutralization efficacy of expired polyvalent antivenoms: an alternative option. | the expense of production and distribution of snakebite antivenom, as well as its relatively infrequent use, has caused antivenom to be increasingly difficult to obtain and ultimately producing an alarming global shortage. unused, expired antivenom may represent a significant, untapped resource to ameliorate this crisis. this study examines the efficacy of expired antivenom over time using in vitro, whole blood clotting, and platelet function statistics. representatives from three years for four ... | 2019 | 31229628 |
| snake venom extracellular vesicles (svevs) reveal wide molecular and functional proteome diversity. | proteins constitute almost 95% of snake venom's dry weight and are produced and released by venom glands in a solubilized form during a snake bite. these proteins are responsible for inducing several pharmacological effects aiming to immobilize and initiate the pre-digestion of the prey. this study shows that proteins can be secreted and confined in snake venom extracellular vesicles (svevs) presenting a size distribution between 50 nm and 500 nm. svevs isolated from lyophilized venoms collected ... | 2018 | 30104604 |
| unique temperature-activated neurons from pit viper thermosensors. | rattlesnakes, copperheads, and other pit vipers have highly sensitive heat detectors known as pit organs, which are used to sense and strike at prey. however, it is not currently known how temperature change triggers cellular and molecular events that activate neurons supplying the pit organ. we dissociated and cultured neurons from the trigeminal ganglia (tg) innervating the pit organs of the western diamondback rattlesnake (crotalus atrox) and the copperhead (agkistrodon contortix) to investig ... | 2004 | 15213055 |
| on the quaternary structure of a c-type lectin from bothrops jararacussu venom--bj-32 (bjcul). | bj-32 (also known as bjcul) is a c-type lectin from the venom of bothrops jararacussu with specificity for beta-galactosides and a remarkable ability to agglutinate several species of trypanosomatids. our objective was to study the oligomerization state of native bj-32 by using different biophysical and computational methods. small-angle x-ray light scattering (saxs) experiments disclosed a compact, globular protein with a radius of gyration of 36.72+/-0.04a and molecular weight calculated as 14 ... | 2008 | 18948130 |
| irreversible inactivation of snake venom l-amino acid oxidase by covalent modification during catalysis of l-propargylglycine. | snake venom l-amino acid oxidase (sv-laao, a flavor-enzyme) has attracted considerable attention due to its multifunctional nature, which is manifest in diverse clinical and biological effects such as inhibition of platelet aggregation, induction of cell apoptosis and cytotoxicity against various cells. the majority of these effects are mediated by h2o2 generated during the catalytic conversion of l-amino acids. the substrate analog l-propargylglycine (lpg) irreversibly inhibited the enzyme from ... | 2013 | 23772385 |
| toxin transcripts in crotalus atrox venom and in silico structures of toxins. | the western diamondback rattlesnake (crotalus atrox) is a common and widespread north american pit viper species, and its venom possesses medical applications. in this research, we identified 14 of the most common transcripts encoding 11 major venom toxins including transcripts for a three-finger toxin (3ftx) from the crude venom of c. atrox. in silico three-dimensional (3d) structures of 9 venom toxins were predicted by using deduced toxin amino acid sequences and a computer programme-modeller. ... | 2020 | 32774833 |
| repurposing cancer drugs batimastat and marimastat to inhibit the activity of a group i metalloprotease from the venom of the western diamondback rattlesnake, crotalus atrox. | snakebite envenomation causes over 140,000 deaths every year, predominantly in developing countries. as a result, it is one of the most lethal neglected tropical diseases. it is associated with incredibly complex pathophysiology due to the vast number of unique toxins/proteins present in the venoms of diverse snake species found worldwide. here, we report the purification and functional characteristics of a group i (pi) metalloprotease (camp-2) from the venom of the western diamondback rattlesna ... | 2020 | 32397419 |
| the origin and diversification of a novel protein family in venomous snakes. | the genetic origins of novelty are a central interest of evolutionary biology. most new proteins evolve from preexisting proteins but the evolutionary path from ancestral gene to novel protein is challenging to trace, and therefore the requirements for and order of coding sequence changes, expression changes, or gene duplication are not clear. snake venoms are important novel traits that are comprised of toxins derived from several distinct protein families, but the genomic and evolutionary orig ... | 2020 | 32366667 |
| comparison of thromboelastography versus conventional coagulation tests in simulated crotalus atrox envenomation using human blood. | pit viper bites are a source of significant morbidity and mortality. pit viper bites can cause venom-induced consumptive coagulopathy (vicc), typically evaluated with laboratory-based conventional coagulation tests (ccts). however, ccts require a laboratory and average 1 h to conduct. thromboelastography (teg) provides real-time, point-of-care tests of coagulation that are fast and require no separate laboratory facilities, which could be advantageous in both hospital and austere settings. howev ... | 2020 | 31833475 |
| venom composition of adult western diamondback rattlesnakes (crotalus atrox) maintained under controlled diet and environmental conditions shows only minor changes. | many species of snakes produce venom as a chemical means of procuring potentially fractious prey. studies have increasingly focused on venom compositional variation between and within individual snakes of the same species/subspecies, with significant differences often being observed. this variation in composition has been attributed to differences in age, season, diet, and environment, suggesting that these factors could help explain the inter- and intra-specific variation found in some snake ve ... | 2019 | 30954451 |
| crotalus atrox disintegrin reduces hemorrhagic transformation by attenuating matrix metalloproteinase-9 activity after middle cerebral artery occlusion in hyperglycemic male rats. | hemorrhagic transformation after ischemic stroke is an independent predictor for poor outcome and is characterized by blood vessel rupture leading to brain edema. to date, no therapies for preventing hemorrhagic transformation exist. disintegrins from the venom of crotalus atrox have targets within the coagulation cascade, including receptors on platelets. we hypothesized that disintegrins from c. atrox venom can attenuate hemorrhagic transformation by preventing activation of matrix metalloprot ... | 2020 | 30242872 |
| penetrating ocular injury by western diamondback rattlesnake. | | 2018 | 30119804 |
| catroxmp-ii: a heme-modulated fibrinogenolytic metalloproteinase isolated from crotalus atrox venom. | it has been recently demonstrated that the hemotoxic venom activity of several species of snakes can be inhibited by carbon monoxide (co) or a metheme forming agent. these and other data suggest that the biometal, heme, may be attached to venom enzymes and may be modulated by co. a novel fibrinogenolytic metalloproteinase, named catroxmp-ii, was isolated and purified from the venom of a crotalus atrox viper, and subjected to proteolysis and mass spectroscopy. an ion similar to the predicted sing ... | 2018 | 29761254 |
| in vitro effects of crotalus atrox snake venom on chick and mouse neuromuscular preparations. | the neuromuscular effect of venoms is not a major clinical manifestation shared between rattlesnakes native to the americas, which showed two different venom phenotypes. taking into account this dichotomy, nerve muscle preparations from mice and chicks were used to investigate the ability of crotalus atrox venom to induce in vitro neurotoxicity and myotoxicity. unlike crotalic venoms of south america, low concentrations of c. atrox venom did not result in significant effects on mouse neuromuscul ... | 2018 | 29604435 |
| effects of purified human fibrinogen modified with carbon monoxide and iron on coagulation in rabbits injected with crotalus atrox venom. | while snake venom derived enzymes, such as the thrombin-like activity possessing ancrod, have been used to treat thrombotic disease by defibrinogenating patients, the therapeutic potential of fibrinogenolytic snake venom enzymes, such as those derived from crotalus atrox, have not been fully explored. however, one of the potential risks of administering fibrinogenolytic enzymes to effect defibrinogenation is hemorrhage secondary to hypofibrinogenemia. the present investigation sought to determin ... | 2017 | 28889321 |
| characterization of the rabbit as an in vitro and in vivo model to assess the effects of fibrinogenolytic activity of snake venom on coagulation. | several in vitro investigations have demonstrated that anticoagulant effects of fibrinogenolytic snake venom metalloproteinases have been abrogated in human plasma by modifying fibrinogen with iron (fe) and carbon monoxide (co) to prevent catalysis or by directly inhibiting these enzymes with co. to translate these findings, we chose to assess the rabbit as a model of envenomation with crotalus atrox venom. it was determined with thrombelastography that 15 times the concentration of venom noted ... | 2018 | 28696521 |
| crotalus atrox venom exposed to carbon monoxide has decreased fibrinogenolytic activity in vivo in rabbits. | envenomation by haemotoxic enzymes remains a significant source of human morbidity and mortality worldwide, with administration of long-acting or multiple doses of antivenom first-line therapy. however, coagulopathy can still occur and recur. of interest, it has been recently demonstrated that direct, isolated exposure of snake venom enzymes with fibrinogenolytic activity to carbon monoxide (co) abrogates venom-mediated loss of coagulation in human plasma. these observations of co inhibition of ... | 2018 | 28691277 |
| when less means more: dehydration improves innate immunity in rattlesnakes. | immune function can vary based on availability of resources, and most studies of such influences have focused on the co-investment of energy into immune and other physiological functions. when energy resources are limited, trade-offs exist, which can compromise immunity for other functions. as with energy, water limitation can also alter various physiological processes, yet water has received little consideration for its possible role in modulating immune functions. we examined the relationship ... | 2017 | 28404727 |
| crotalus atrox venom preconditioning increases plasma fibrinogen and reduces perioperative hemorrhage in a rat model of surgical brain injury. | perioperative bleeding is a potentially devastating complication in neurosurgical patients, and plasma fibrinogen concentration has been identified as a potential modifiable risk factor for perioperative bleeding. the aim of this study was to evaluate preconditioning with crotalus atrox venom (cv-pc) as potential preventive therapy for reducing perioperative hemorrhage in the rodent model of surgical brain injury (sbi). c. atrox venom contains snake venom metalloproteinases that cleave fibrinoge ... | 2017 | 28102287 |
| identification of lys49-pla2 from crude venom of crotalus atrox as a human neutrophil-calcium modulating protein. | we fortuitously observed a human neutrophil intracellular free-calcium concentration ([ca(2+)]i) increasing activity in the commercially available phosphodiesterase i (pde i), which is actually dried crude venom of crotalus atrox. as this activity was not observed with another commercially available pure pde i, we tried to find out the causative molecule(s) present in 'crude' pde, and identified lys49-phospholipase a2 (lys49-pla2 or k49-pla2), a catalytically inactive protein which belongs to th ... | 2016 | 26937214 |
| responses of infrared-sensitive tectal units of the pit viper crotalus atrox to moving objects. | rattlesnakes perceive ir radiation with their pit organs. this enables them to detect and strike towards warm-blooded prey even in the dark. in addition, the ir sense allows rattlesnakes to find places for thermoregulation. animate objects (e.g., prey) tend to move and thus cause moving ir images across the pit membrane. even when an object is stationary, scanning head movements of rattlesnakes will result in moving ir images across the pit membrane. we recorded the neuronal activity of ir-sensi ... | 2016 | 26906281 |