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serosurveillance of eastern equine encephalitis virus in amphibians and reptiles from alabama, usa.eastern equine encephalitis virus (eeev) is among the most medically important arboviruses in north america, and studies suggest a role for amphibians and reptiles in its transmission cycle. serum samples collected from 351 amphibians and reptiles (27 species) from alabama, usa, were tested for the presence of antibodies against eeev. frogs, turtles, and lizards showed little or no seropositivity, and snakes had high seropositivity rates. most seropositive species were preferred or abundant host ...022403333
distribution in the mouse of lethal and sub-lethal doses of cottonmouth moccasin venom labelled with iodine-131. 195913827299
studies on the biologic relationship of endotoxin and other toxic proteins. i. comparison of the properties of snake venom and endotoxin.1. agkistrodon piscivorus venom and e. coli endotoxin were shown to be immunologically distinct, and to differ in certain biologic properties: effects on immune response, body temperature, and circulating leukocyte count, and capacity to prepare for and provoke the local and generalized shwartzman reaction. 2. neither a single prior injection of venom nor the existence of hyperimmunity to lethal doses of venom protected rabbits against the local and generalized shwartzman reaction. 3. serial int ...196213880807
studies on the biologic relationship of endotoxin and other toxic proteins. ii. enhancement of susceptibility to snake venom by endotoxin.1. injections of sublethal quantities of agkistrodon piscivorus venom into endotoxin-treated rabbits produces a consistent early death. 2. the endotoxin-induced hypersusceptibility state (eihs) to venom is produced by intravenous, intradermal, and intraperitoneal administration of endotoxin. the latency and duration of the eihs vary with the route of administration. 3. eihs is induced by as little as 1 gamma of endotoxin administered intravenously. although the degree of susceptibility was no gr ...196213916025
block of conduction by acetylcholine and d-tubocurarine after treatment of squid axon with cottonmouth moccasin venom. 196214493975
the effect of edta on the extent of tissue damage caused by the venoms of bothrops atrox (fer-de-lance) and agkistrodon piscivorus (cottonmouth moccasin). rep 596. 196314131257
the effects of x-irradiation on the biological activity of cottonmouth moccasin (agkistrodon piscivorus) enom. rep 588. 196314131243
demonstration of increased permeability as a factor in the effect of acetylcholine on the electrical activty of venom-treated axons.d-tubocurarine (curare) and acetylcholine (ach) had been found to block electrical activity after treatment of squid giant axons with cottonmouth moccasin venom at a concentration which had no effect on conduction. it has now been demonstrated that this effect is attributable to reduction of permeability barriers. the penetration of externally applied c(14)-labeled dimethylcurare, ach, choline, and trimethylamine into the axoplasm of the squid giant axon was determined in axons treated with eith ...196313974908
amylase in the cottonmouth water moccasin, agkistrodon piscivorus. 196414246360
the chemical modification of necrogenic and proteolytic activities of venom and the use of edta to produce agkistrodon piscivorus venom toxoid. 196414301289
the effects of x-irradiation on the antigenic character of ancistrodon piscivorus (cottonmouth moccasin) venom. rep no. 607. 196414264651
the poison gland of the cottonmouth moccasin, ancistrodon p. piscivorus, as observed with the electron microscope. 196514336221
penetration of sugars, steroids, amino acids, and other organic compounds into the interior of the squid giant axon.squid axons were exposed to solutions of c(14)-labeled compounds. after 60 minutes the axoplasm was extruded and assayed for radioactivity. the following compounds penetrated to about 3 per cent of what would have been expected had there been no barrier to free diffusion and the subsequent attainment of equivalent distribution: mannitol, sucrose, glutamate, glutamine, aspartate, 3,4-dihydroxyphenylalanine, 3,4-dihydroxyphenylethylamine, lambda-aminobutyrate, serotonin, and dehydroepiandrosterone ...19655862505
the effect of edta on the extent of tissue damage caused by the venoms of bothrops atrox and agkistrodon piscivorus. 196514298231
detoxification of the venoms of the russell's viper (vipera russellii) and water moccasin (agkistrodon piscivorus) by photooxidation. rep no. 629. 19655295049
thiabendazole inhibition of venom necrosis.thiabendazole (200 mcg/ml) completely inibited the tissue damaging activity of cotton-mouth moccasin venom (300 mcg/ml) when incubated together for one hour at room temperature and injected intradermally into the guinea pig. thiabendazole (0.15 ml of 200 mcg/ml) injected immediately after the venom decreased tissue damage from cottonmouth moccasin venom (0.05 ml of 600 mcg/ml). thiabendazole or other chelating agents may be of future value in decreasing tissue damage from venoms containing prote ...196625622354
effects of x-irradiation on the antigenic character of agkistrodon piscivorus (cottonmouth moccasin) venom. 19664162685
detoxification of russell's viper (vipera russellii) and water moccasin (agkistrodon piscivorus) venoms by photooxidation. 19665938782
polysaccharide content of the poison apparatus of the cottonmouth moccasin agkistrodon piscivorus piscivorus. 19674229870
penetration of an organphosphorus compound into squid axon and its effects on metabolism and function.the tertiary analogute of phospholine, namely, (c(2)h(5)o)(2)p(o)sch(2)ch(2)n(ch(3))(2), is a potent, irreversible inhibitor of cholinesterase which, when externally applied to the sqluid giant axon, readily penetrates in its inhibitory form into the axoplasm. however, even a 10(-2) molar solution of this compound does not block axonal conduction unless the axon is first treated with a low concentration of venom from the cottonmouth moccasin. the question of the activity of acetylcholinesterase ...19676023264
bites by cottonmouths (ancistrodon piscivorus) in the united states. 19676021542
fine structural alterations associated with venom action on squid giant nerve fibers.(1) block of conduction and marked increase in permeability of the squid giant axon, when surrounded by adhering small nerve fibers, is caused by the venoms of cottonmouth, ringhals, and cobra snakes and by phospholipase a (pha). this phenomenon is associated with a marked breakdown of the substructure of the schwann sheath into masses of cytoplasmic globules. low concentrations of these agents which render the axons sensitive to curare cause less marked changes in the structure of the sheath. ( ...19684170546
isolation of a phospholipase a from agkistrodon piscivorus venom. 19705462424
comparison of hemorrhagic factors of the venoms of naja naja, agkistrodon piscivorus and apis mellifera. 19705315472
structural and respiratory effects of agkistrodon piscivorus phospholipase a on rat liver mitochondria. 19705416109
cottonmouth moccasin venom: fractionation of toxic and allergenic components and interaction with tissue mast cells. 19715098982
distribution and excretion of 3h-venoms of crotalus adamanteus, crotalusatrox, and agkistrodon piscivorus and 3h-serum of lampropeltis getulus in rats. 19725058627
some effects of guinea pig serum and heparin on hemolysis induced by naja naja, agkistrodon piscivorus and apis mellifera venom. 19725070580
lateral jaw and throat musculature of the cottonmouth snake. agkistrodon piscivorus. 19734730629
lysis of red blood cells in some haemolytic anaemias--the lytic effect of agkistrodon piscivorus venom in vitro.the lysis of red blood cells induced by the agkistrodon piscivorus venom (apv) in vitro in the presence and/or in the absence of plasma was examined in autoimmune haemolytic anaemia (aiha), hereditary spherocytosis (hs) and paroxysmal nocturnal haemoglobinuria (pnh). virtually haemolysis did not differ from that of normals in aiha, it was slightly increased in hs and significantly higher in pnh, however, only in the presence of autologous or normal homologous plasma. the mechanism of pnh blood c ...197772030
morphological study of lesions induced by snake venoms (naja naja and agkistrodon piscivorus) in the lung and cremaster vessels of rats.the morphological effects of two snake venoms, n. naja and a. piscivorus, and of the direct lytic factor and phospholipase-a, compounds purified from n. naja crude venom, were investigated on lung and cremaster vessels of rats. the microcirculation of the rat reacts to these two venoms differently: n. naja produces congestion, haemolysis and increased vascular permeability, whereas a. piscivorus causes these alterations, plus haemorrhage and thrombosis. direct lytic factor elicits reponses simil ...1977881630
subnuclear organization of the ophidian trigeminal motor nucleus. ii. ultrastructural measurements on motoneurons innervating antagonistic muscles.horseradish peroxidase (hrp), injected intramuscularly, specifically labeled motoneurons innervating antagonistic jaw muscles in the cottonmouth mocassin, agkistrodon piscivorus piscivorus. adductor mandibulae profundus, part 3a, motoneurons were localized in the lateral regions of the ventral and intermediate subnuclei of the trigeminal (v) motor nucleus. these were large cells containing fine, granular reaction product characteristic of alpha-motoneurons. small cells, which contained large coa ...19807391269
the haemorrhagic exudate and its possible relationship to neurogenic inflammation.the morphological effects of an aqueous solution of nistatin, of clostridium septicum and tityus serrulatus toxins, of bothrops jararaca and agkistrodon piscivorus venoms on the vessels of the tendinous portion of the diaphragm were investigated in guinea-pigs. it was demonstrated that all these substances, when injected intrapleurally induced not only an increase in the permeability of venules but also haemorrhages originating at this segment of the microcirculation. red cells were shown to esc ...19807400880
subnuclear organization of the ophidian trigeminal motor nucleus. i. localization of neurons and synaptic bouton distribution.among the reptilia the morphology of the trigeminal (v) motor nucleus is a rather good indicator of the sophistication of jaw kinetics. as it becomes more complex, the nucleus shifts ventrolaterally and becomes divisible into subnuclear groups. the cottonmouth moccasin, a pit viper with very finely developed jaw musculature and kinetics, has a very large v motor nucleus. it is divisible into three subnuclei: the ventral and intermediate, containing predominantly large neurons (40--60 micrometers ...19807391268
fractionation and partial characterization of toxic components of agkistrodon p. piscivorus (eastern cottonmouth moccasin) venom. 19817336449
fine structure and organization of the infrared receptor relay, the lateral descending nucleus of the trigeminal nerve in pit vipers.the morphology of the nucleus of the lateral descending tract of v has been studied in species of two genera of pit vipers, cottonmouth moccasin (agkistrodon piscivorus piscivorus), and rattlesnake (crotalus ruber and crotalus horridus horridus). the nucleus is the site of termination of primary afferent neurons forming the infrared receptors in the facial pits. it is located on the external surface of the common descending tract of v and contains somata that range in size from 7 to 22 micromete ...19817204672
thrombin-like and fibrinolytic enzymes in the venoms from the gaboon viper (bitis gabonica), eastern cottonmouth moccasin (agkistrodon p. piscivorus) and southern copperhead (agkistrodon c. contortrix) snakes.crude venom from b. gabonica contained weak fibrinogen clotting activity but no visible fibrinolytic activity, whereas venoms from a. p. piscivorus and a. c. contortrix exhibited fibrinolytic activity (by fibrin plate assay) but no thrombin-like activity. these snake venoms were fractionated on sephadex g-100 with the following results. thrombin-like activity in b. gabonica venom was eluted in a single protein peak with a molecular weight of 40,000. agkistrodon p. piscivorus venom contained a si ...19827043785
isolation and characterization of three ca2+-dependent beta-galactoside-specific lectins from snake venoms.three lactose-inhibited lectins from the venoms of the snakes agkistrodon contortrix contortrix (southern copperhead), ancistrodon piscivorous leukostoma (western cottonmouth moccasin) and crotalus atrox (western diamondback rattlesnake) have been isolated and newly characterized. the three lectins are similar to thrombolectin, a lectin isolated from the venom of bothrops atrox (fer-de-lance) (gartner, stocker & williams, 1980), with regard to sugar specificity, mr, ca2+ requirements and sensiti ...19846391472
[complement and noncomplement hemolysis of blood cells in patients with various blood diseases after the administration of the crude toxins of agkistrodon piscivorus, naja naja, naja oxiana]. 19846515308
use of some snake venoms in the diagnostics of paroxysmal nocturnal hemoglobinuria (pnh).the crude toxin of agkistrodon piscivorus was found to produce hemolysis of pnh erythrocytes by way of complement activation, however the degree of pnh blood cell lysis was lower than in other techniques used. the crude toxins of naja naja and naja oxiana cause much higher hemolysis though lower hemolysis takes place in normal blood cells. in some normal persons and different blood diseases it is responsible for high hemolysis even when the complement is absent. from naja naja toxin a fraction c ...19852410338
detection of specific proenzyme activators in snake venoms by a new immunoabsorbant-chromogenic substrate method.in separate experiments, antibodies to plasminogen, factor x and protein c were applied to microtitre trays as commonly used in enzyme-linked immunoassays. after incubation with dilute normal human plasma as a source of the corresponding proenzyme antigen, the wells were exposed to dilutions of various snake venoms. after thorough washing, the microtitre tray wells were tested overnight with chromogenic tripeptide substrates known to be relatively specific for the activated forms of the above fa ...19853841012
in vivo effects of snake venoms on passive and facilitated glucose transport across blood-ocular and blood-csf barriers of the rat.the transport of (3h)-3-0-methyl-d-glucose (md-glu) and (14c)-l-glucose (l-glu) across blood-ocular and blood-cns barriers was studied in rats with previously introduced (i.v.) lethal doses of lyophilized venom from one of three venomous snakes; mojave rattlesnake, crotalus scutulatus; cottonmouth mocassin, agkistrodon piscivorus; yellow cobra, naja nivea. transport rate constants calculated for md-glu are taken as an indication of carrier-mediated transport, whereas l-glu constants are consider ...19853992599
the lysine-49 phospholipase a2 from the venom of agkistrodon piscivorus piscivorus. relation of structure and function to other phospholipases a2.a new class of phospholipases a2 that have a lysine at position 49 differ from the more conventional asp-49 enzymes with respect to the sequential binding of the essential cofactor, calcium, and the substrate, phospholipid, in the formation of the catalytic complex (maraganore, j.m., merutka, g., cho, w., welches, w., kézdy, f.j., and heinrikson, r.l. (1984) j. biol. chem. 259, 13839-13843). we report here the complete amino acid sequence of the lys-49 enzyme from agkistrodon piscivorus piscivor ...19863082870
protein c activators in snake venoms.venoms of 32 snake species were tested for protein c (pc) activating potency. as measured with the chromogenic pc substrate d-pro-l-pro-l-arg-pna, eleven venoms were able to generate amidolytic activity from purified bovine pc. in five venom solutions (bothrops moojeni, b. pradoi, cerastes cerastes, vipera lebetina and v. russellii) the pc activating potency was destroyed during 10 min heating at 70 degrees c at ph 3, whereas in six venom solutions (agkistrodon contortrix contortrix, a. c. mokas ...19863755037
crystallization and preliminary diffraction studies of the lys-49 phospholipase a2 from agkistrodon piscivorus piscivorus.previous chemical and structural studies have proposed a major role for asp-49 in the calcium-mediated activation of phospholipases a2. recently, a new class of phospholipases a2 has been characterized with a lysine in the place of aspartate at position 49 (maraganore, j. m., merutka, g., cho, w., welches, w., kézdy, f. j., and heinrikson, r. l. (1984) j. biol. chem. 259, 13839-13843; maraganore, j. m., and heinrikson, r. l. (1986) j. biol. chem. 261, 4797-4804). although both the lys-49 and asp ...19863091601
isolation and characterization of lactose-binding lectins from the venoms of the snakes lachesis muta and dendroaspis jamesonii.two lectins have been isolated: one from the venom of lachesis muta (bushmaster lectin) and one from dendroaspis jamesonii venom (jameson's mamba lectin). the lectin from bushmaster venom (bml) is similar to the lactose-binding lectins previously isolated from snake venoms (gartner et al. (1980) febs lett. 117, 13-16; gartner & ogilvie (1984) biochem. j. 224, 301-307) in that it is calcium-dependent, lactose inhibitable, and is a dimer of molecular weight 28,000. in contrast, the lactose-blockab ...19863571179
comparison of enzymatic and pharmacological activities of lysine-49 and aspartate-49 phospholipases a2 from agkistrodon piscivorus piscivorus snake venom.the basic lys-49 phospholipase a2 (pla2) from agkistrodon piscivorus piscivorus venom is homologous to the basic asp-49 pla2 from the same venom as well as other snake venom pla2 enzymes. it differs, however, in several respects, most important being replacement of the previously invariant asp-49 at the calcium binding site by lys, resulting in a reversed order of addition of calcium and phospholipid, phospholipid binding first. although the preferences for phospholipid substrates of the two enz ...19873109429
the chemical basis for interfacial activation of monomeric phospholipases a2. autocatalytic derivatization of the enzyme by acyl transfer from substrate.a basic monomeric phospholipase a2 from the venom of the american water moccasin, agkistrodon piscivorus piscivorus, undergoes ca2+-dependent, autocatalytic acylation during the course of hydrolysis of both model and natural phospholipid substrates. acylation occurs at 2 lysine residues, lys-7 and lys-10, in the nh2-terminal alpha-helical segment of the enzyme, and when both positions are fully derivatized, the stable bisacylphospholipase a2 becomes a dimer in solution. the acylated enzyme is fu ...19883403524
the role of aspartic acid-49 in the active site of phospholipase a2. a site-specific mutagenesis study of porcine pancreatic phospholipase a2 and the rationale of the enzymatic activity of [lysine49]phospholipase a2 from agkistrodon piscivorus piscivorus' venom.in order to probe the role of asp-49 in the active site of porcine pancreatic phospholipase a2 two mutant proteins were constructed containing either glu or lys at position 49. their enzymatic activities and their affinities for substrate and for ca2+ ions were examined in comparison with the native enzyme. enzymatic characterization indicated that the presence of asp-49 is essential for effective hydrolysis of phospholipids. conversion of asp-49 to either glu or lys strongly reduces the binding ...19883046944
platelet-aggregation is stimulated by lactose-inhibitable snake venom lectins.five lactose-specific lectins from snake venoms were tested for the ability to stimulate the aggregation of human platelets. three of the lectins, bushmaster (lachesis muta), cottonmouth (ancistrodon piscivorous leukostoma) and rattlesnake (crotalus atrox) lectins, consistently stimulated secretion and aggregation. thrombolectin (bothrops atrox) occasionally caused aggregation. copperhead (agkistrodon contortrix contortrix) lectin did not by itself cause platelet aggregation. lactose, a specific ...19892530646
the role of asp-49 and other conserved amino acids in phospholipases a2 and their importance for enzymatic activity.the role of aspartic acid-49 (asp-49) in the active site of porcine pancreatic phospholipase a2 was studied by recombinant dna techniques: two mutant proteins were constructed containing either glutamic acid (glu) or lysine (lys) at position 49. enzymatic characterization indicated that the presence of asp-49 is essential for effective hydrolysis of phospholipids. conversion of asp-49 to either glu or lys strongly reduces the binding of ca2+ ions, in particular for the lysine mutant, but the aff ...19892722967
agkistrodon piscivorus piscivorus platelet aggregation inhibitor: a potent inhibitor of platelet activation.applaggin (agkistrodon piscivorus piscivorus platelet aggregation inhibitor) is a potent inhibitor of platelet activation. the protein is isolated from the venom of the north american water moccasin snake in three steps, including gel filtration, cation exchange, and reverse-phase hplc procedures. the purified protein migrates as a 17,700-da polypeptide by sds/page under nonreducing conditions and as a 9800-da peptide in the presence of thiol. the behavior of applaggin on sds/page would indicate ...19892510158
the temporal sequence of events in the activation of phospholipase a2 by lipid vesicles. studies with the monomeric enzyme from agkistrodon piscivorus piscivorus.the substrate dependence of the time courses of hydrolysis of both small and large unilamellar vesicles of dipalmitoylphosphatidylcholine (dppc) by agkistrodon piscivorus piscivorus monomeric phospholipase a2 is consistent with an activation process involving enzyme aggregation on the vesicle surface. the time course of hydrolysis of large unilamellar vesicles is particularly complex; a slow initial rate of hydrolysis is followed by an extremely abrupt increase in enzyme activity. the length of ...19892745435
thermodynamic and kinetic studies of the interaction of vesicular dipalmitoylphosphatidylcholine with agkistrodon piscivorus piscivorus phospholipase a2.the tryptophan fluorescence emission intensity at 340 nm of monomeric phospholipase a2 from agkistrodon piscivorus piscivorus increased about 70% upon addition of dipalmitoylphosphatidylcholine small unilamellar vesicles (dppc suv) at 25 degrees c. the emission spectrum was also blue-shifted 6-8 nm, suggesting that the environment of 1 or more tryptophan residues had become less polar. this effect of suv on the phospholipase a2 fluorescence was independent of ca2+ at 25 degrees c, and the appare ...19892909516
comparison of enzymatic and pharmacological activities of lysine-49 and aspartate-49 phospholipases a2 from agkistrodon piscivorus piscivorus snake venom. a reconsideration. 19892506677
hplc-based two-step purification of fibrinolytic enzymes from the venom of agkistrodon contortrix contortrix and agkistrodon piscivorus conanti.in investigations aimed at characterizing snake venom blood clot-dissolving enzymes, we have developed a rapid two-step high-performance chromatography method for the isolation of these fibrinolytic enzymes from the venoms of agkistrodon contortrix contortrix and agkistrodon piscivorus conanti. the first step consisted of hydrophobic interaction chromatography on a propyl-aspartamide column. fractions containing the fibrinolytic activity were then concentrated and applied to a hydroxylapatite co ...19902152182
use of flow cytometry to screen for the effects of environmental mutagens: baseline dna values in cottonmouth snakes. 19902279132
binding of the snake venom-derived proteins applaggin and echistatin to the arginine-glycine-aspartic acid recognition site(s) on platelet glycoprotein iib.iiia complex inhibits receptor function.in the present report we describe the platelet-binding characteristics of applaggin and echistatin, potent inhibitors of fibrinogen-dependent platelet aggregation derived from agkistrodon piscivorus piscivorus and echis carinatus snake venoms, respectively. both molecules bound to unstimulated platelets in a specific and saturable manner. at saturation there were 37,100 +/- 3,150 (mean, +/- s.d.) molecules of applaggin and 27,200 +/- 2,816 molecules of echistatin bound/platelet, with dissociatio ...19902365698
myotoxin ii from bothrops asper (terciopelo) venom is a lysine-49 phospholipase a2.a basic, dimeric myotoxic protein, myotoxin ii, purified from bothrops asper venom has a similar molecular weight and is immunologically cross-reactive with antibodies raised to previously isolated b. asper phospholipases a2, except that it shows only 0.1% of the phospholipase activity against l-alpha-phosphatidylcholine in the presence of triton x-100. its 121 amino acid sequence, determined by automated edman degradation, clearly identifies it as a lys-49 phospholipase a2. key amino acid diffe ...19911899180
immunological properties of the fibrinolytic enzyme (fibrolase) from southern copperhead (agkistrodon contortrix contortrix) venom and its purification by immunoaffinity chromatography.an antibody to the fibrinolytic enzyme in southern copperhead venom was produced by immunizing rabbits with chromatographically purified enzyme. the antibody was purified from rabbit blood by ammonium sulfate fractionation and protein-a affinity chromatography. the purified antibody reacted only with the fibrinolytic enzyme in southern copperhead venom as demonstrated by immunodiffusion and immunoelectrophoresis. western immunoblotting revealed that several snake venoms, including agkistrodon pi ...19911926169
neutralization of kinin-releasing enzymes of crotalid venoms by monospecific and polyspecific antivenoms.the amounts of kinin-releasing enzymes in the venoms of crotalus atrox, crotalus adamanteus, crotalus scutulatus scutulatus and agkistrodon piscivorus piscivorus were measured by determining the amounts of kinin released from a sheep kininogen substrate by means of a specific radioimmunoassay. four monospecific and two commercial polyspecific antivenom igg samples were tested for their ability to reduce the kinin-releasing activities of the four crotalid venoms measured in vitro. all of the anti ...19911926178
treatment of snakebite poisoning.the epidemiology, mechanics, prevention, pharmacology, clinical manifestations, and treatment of snakebites are reviewed. poisonous snakes bite approximately 8000 persons annually in the united states, causing approximately 12-15 deaths per year. pit vipers (rattlesnakes, copperheads, cottonmouths, and massasaugas) are responsible for 99% of all snakebite poisonings; coral snakes and other foreign exotic species are responsible for the additional 1%. envenomation is characterized by pain, edema, ...19911781479
effects of ph and calcium ion on self-association properties of two dimeric phospholipases a2.the monomer-dimer equilibria of the dimeric phospholipases a2 from crotalus atrox and agkistrodon piscivorus piscivorus venoms were examined chromatographically as a function of ph and in the presence versus absence of the essential cofactor, calcium ion. at neutral ph without calcium, the subunits of both enzymes reequilibrated sufficiently slowly that dimer and monomer were separated by size exclusion chromatography. at ph 4.2 and lower, the dimers underwent rapid dissociation and reassociatio ...19911885568
molecular details of the activation of soluble phospholipase a2 on lipid bilayers. comparison of computer simulations with experimental results.the initial rate of hydrolysis of large unilamellar vesicles of dipalmitoylphosphatidylcholine by phospholipase a2 from the venom of agkistrodon piscivorus piscivorus is small and elevates gradually until it suddenly increases by a factor of 10 to 1000 depending on the experimental conditions. this abrupt onset of high enzyme activity appears to be correlated to a specific mole fraction of reaction product at which point a cooperative compositional phase transition in the bilayer occurs. five mo ...19921597446
citrate is a major component of snake venoms.citrate has been identified as a major component of snake venoms by gas liquid chromatography and mass spectrometry. the venoms of bothrops asper, crotalus atrox, crotalus viridis viridis, crotalus adamanteus, sistrurus miliarius barbouri, crotalus horridus horridus, agkistrodon contortrix mokasen, agkistrodon contortrix contortrix and agkistrodon piscivorus piscivorus contain citrate at concentration levels which can serve as effective buffers. calcium, magnesium, zinc, iron, sodium and potassi ...19921626327
expression of a group ii phospholipase a2 from the venom of agkistrodon piscivorus piscivorus in escherichia coli: recovery and renaturation from bacterial inclusion bodies.a synthetic gene encoding the group ii phospholipase a2 (pla2) from the venom of agkistrodon piscivorus piscivorus has been constructed and expressed with high efficiency in escherichia coli. no enzymatic activity was recovered when the polypeptide contained the initiator met residue. replacement of an asn residue penultimate to the initiator met with ser or gly permitted removal of the initiator met by the endogenous methionine aminopeptidase. the amino-terminal serine (n-ser) and amino-termina ...19921336691
calcium and magnesium dependence of phospholipase a2-catalyzed hydrolysis of phosphatidylcholine small unilamellar vesicles.the ca2+ requirement for lipid hydrolysis catalyzed by phospholipase a2 from agkistrodon piscivorus piscivorus (app-d49) and porcine pancreas has been examined using small, unilamellar vesicles of dipalmitoylphosphatidylcholine (dppc suv). hydrolysis was affected by product inhibition even at early times, and the extent of this inhibition depended on the concentration of divalent cations. the ca2+ requirement for half-maximal rates of hydrolysis reflected, in part, this non-catalytic role of div ...19921400456
local heat and cold application after eastern cottonmouth moccasin (agkistrodon piscivorus) envenomation in the rat: effect on tissue injury.we studied the effect of local application of heat or cold on the development of tissue necrosis in envenomated rats. anesthetized animals had 6 mg/kg venom from agkistrodon piscivorus injected subcutaneously into the lateral aspect of a hind limb. heat or cold was applied to the site of envenomation in the experimental groups for 4-6 hr, and the injected area was examined histologically after 24 hr. neither local treatment, with or without the presence of systemic antivenin, significantly affec ...19921485335
reversibility of the activation of soluble phospholipase a2 on lipid bilayers: implications for the activation mechanism.the time-courses of hydrolysis of large vesicles of dipalmitoylphosphatidylcholine were compared using four species of phospholipase a2 (agkistrodon piscivorus piscivorus, crotalus adamanteus and naja naja venoms and porcine pancreatic). in all four cases, the hydrolysis rate suddenly increases 10 to 100-fold at the time (tau) when a specific mole fraction of reaction products has accumulated. the intrinsic fluorescence emission of the three venom enzymes also increases suddenly at time tau. bot ...19921643108
an examination of structural interactions presumed to be of importance in the stabilization of phospholipase a2 dimers based upon comparative protein sequence analysis of a monomeric and dimeric enzyme from the venom of agkistrodon p. piscivorus.phospholipases a2 may exist in solution both as monomers and dimers, but enzymes that form strong dimers (kd approximately 10(-9) m) have been found, thus far, only in venoms of the snake family crotilidae. the complete amino acid sequences of a basic monomeric and an acidic dimeric phospholipase a2 from agkistrodon piscivorus piscivorus (american cottonmouth water moccasin) venom have been determined by protein sequencing methods as part of a search for aspects of structure contributing to form ...19938489705
the lysine-49 phospholipase a2 from the venom of agkistrodon piscivorus piscivorus. relation of structure and function to other phospholipases a2. 19938449964
effects of specific fatty acid acylation of phospholipase a2 on its interfacial binding and catalysis.monomeric phospholipase a2 (pla2) from the venom of agkistrodon piscivorus piscivorus (app-d49) was treated with 3-acyloxy-4-nitrobenzoic acids to acylate the epsilon-amino groups of two lysines (lys-7 and lys-10) in the amino terminal region. resulting 7,10-diacylated-app-d49s, with acyl groups ranging from lauroyl to palmitoyl, spontaneously aggregated in solution. by contrast, 7,10-dioctanoyl-app-d49 existed as a monomer under the same condition. kinetic and interfacial binding properties of ...19947918373
presence of heat-stable hemorrhagic toxins in snake venoms.twenty-eight snake venoms (seven agkistrodon venoms, six bothrops venoms, 13 crotalus venoms, one sistrurus venom, and one bitis venom) were examined for the presence of heat-stable (100 degrees c, 5 min) hemorrhagic toxins. both heated and unheated venoms were analyzed for their protein composition by sds-page, and tested for their hemorrhagic activity in vivo in mice and for their proteolytic activity on two different substrates. heating all venoms led to the denaturation and loss of some prot ...19947985199
quantification of the interaction between lysolecithin and phospholipase a2.the rate of hydrolysis of phosphatidylcholine bilayers by phospholipase a2 may be either enhanced or inhibited by the presence of lysolecithin depending on the experimental conditions examined. to further understand the relationship of lysolecithin to phospholipase a2 activity, the binding of lysolecithin to phospholipase a2 from the venom of agkistrodon piscivorus piscivorus was examined by fluorescence spectroscopy. the tryptophan emission intensity of the enzyme was enhanced by 70% upon addit ...19948130262
the crystal structure of a lysine 49 phospholipase a2 from the venom of the cottonmouth snake at 2.0-a resolution.the crystal structure of a lysine 49 variant phospholipase a2 (k49 pla2) has been determined at 2.0-a resolution. this particular phospholipase a2, purified from the venom of the eastern cottonmouth (agkistrodon piscivorus piscivorus), a north american pit viper, differs significantly from others studied crystallographically because of replacement of the aspartate residue at position 49, whose side chain is important in calcium binding, by lysine. the crystallographic analysis of k49 pla2 was un ...19942120215
apparent fatal snakebite in three hawks.based on histories and gross and histologic findings, snakebite was diagnosed in three dead raptors submitted for post-mortem examination from northern florida and southern georgia (usa). two immature red-tailed hawks (buteo jamaicensis) were found next to dead and partially eaten venomous snakes. an adult cooper's hawk (accipiter cooperii) was found adjacent to a den containing a cotton-mouth (agkistrodon piscivorus) and an eastern diamondback rattlesnake (crotalus adamanteus). gross findings i ...19947760504
highly efficient immobilization of phospholipase a2 and its biomedical applications.a new method for the immobilization of phospholipase a2 (pla2) has been developed to enhance the activity retention of immobilized pla2. when pla2 from the venom of agkistrodon piscivorus piscivorus was pretreated with 4-nitro-3-octanoyl-oxybenzoic acid to acylate epsilon-amino groups of two lysines (lys-7 and lys-10) and the resulting acylated enzyme was covalently coupled onto carbonyldiimidazole-activated cross-linked agarose beads, the immobilized acylated enzyme showed high retention of act ...19957658163
structure and effects of a kinin potentiating fraction f (appf) isolated from agkistrodon piscivorus piscivorus venom.the contractile action of bradykinin on isolated smooth muscles is known to be potentiated by special peptides isolated from snake venoms and other animal sources. a fraction f (appf) has been derived from agkistrodon piscivorus piscivorus venom. this fraction does not increase the depressor effect of bradykinin n blood pressure, potentiates the action of bradykinin on isolated guinea-pig ileum and prolongs the duration of relaxation in isolated rat duodenum. this fraction was able to inhibit th ...19958599182
effects of temperature and glycerides on the enhancement of agkistrodon piscivorus piscivorus phospholipase a2 activity by lysolecithin and palmitic acid.the effect of temperature and various glycerides to modulate the ability of lysolecithin and fatty acid to promote high phospholipase a2 activity was studied using dipalmitoylphosphatidylcholine large unilamellar vesicles as substrate. the length of the lag phase prior to the accumulation of sufficient hydrolysis products (lysolecithin and fatty acid) to support high phospholipase activity was shortest at temperatures near the thermotropic phase transition of the phospholipid substrate. a reduct ...19957547886
purification and characterization of piscivorase i and ii, the fibrinolytic enzymes from eastern cottonmouth moccasin venom (agkistrodon piscivorus piscivorus).fibrinolytic enzymes, piscivorase i and ii, were isolated from agkistrodon piscivorus piscivorus (eastern cottonmouth moccasin) venom using gel filtration on bio-gel p-100 and ion-exchange chromatography on cm-sepharose cl-6b. the mol. wts of these proteases, piscivorase i and ii, are 23,400 and 29,000 and isoelectric points are 6.6 and 8.5, respectively. these fibrinolytic enzymes were homogeneous by sds-polyacrylamide gel electrophoresis. piscivorase i readily cleaved the a alpha- and b beta-c ...19958588217
enhancement of agkistrodon piscivorus piscivorus venom phospholipase a2 activity toward phosphatidylcholine vesicles by lysolecithin and palmitic acid: studies with fluorescent probes of membrane structure.the activity of phospholipase a2 from snake venom to hydrolyze bilayers of phosphatidylcholines is greatly enhanced by the presence of the hydrolysis products, lysolecithin and fatty acid, in the bilayer. the fluorescence of several probes of membrane structure was used to monitor changes in bilayer physical properties during vesicle hydrolysis. these changes were compared to emission spectra and fluorescence polarization results occurring upon direct addition of lysolecithin and/or fatty acid t ...19957794890
structure of a calcium-independent phospholipase-like myotoxic protein from bothrops asper venom.myotoxin ii, a myotoxic calcium-independent phospholipase-like protein isolated from the venom of bothrops asper, possesses no detectable phospholipase activity. the crystal structure has been determined and refined at 2.8 a to an r-factor of 16.5% (f > 3sigma) with excellent stereochemistry. amino-acid differences between catalytically active phospholipases and myotoxin ii in the ca(2+)-binding region, specifically the substitutions tyr28-->asn, gly32-->leu and asp49-->lys, result in an altered ...199515299297
autocatalytic acylation of phospholipase-like myotoxins.several snake venoms contain a phospholipase a2 in which position 49 in the active site is occupied by a lysine or a serine instead of the aspartate residue normally found. although these proteins do not bind ca2+ and are devoid of catalytic activity, they are still highly specific myotoxins and have recently been shown to induce membrane leakage by a new type of cytolytic mechanism. three of these toxins, myotoxin ii from bothrops asper, ammodytin l from vipera ammodytes, and the k49 protein fr ...19957718570
snakebite treatment at a southeastern regional referral center.our objective was to determine the prevalence of poisonous snakebite victims admitted to a regional trauma center in southeastern georgia over a 10-year period, as well as the type of snake, grade of envenomation, treatment administered, morbidity and mortality, and outcome. records of patients admitted to the center for snakebite from a 24-county catchment area during the 10-year period (january 1984 to january 1994) were retroactively reviewed. sixty-three (63) bites in 62 victims of venomous ...19957661472
pit viper bites: rational management in locales in which copperheads and cottonmouths predominate.the management of pitviper bites remains controversial. in order to better assess the efficacy of different treatment modalities, charts of 107 patients hospitalized for pitviper bites at university of north carolina hospitals between 1952 and 1992 were retrospectively reviewed. the series included 68 copperhead bites (64%), 8 cottonmouth bites (7%), 3 rattlesnake bites (3%), and 28 bites (26%) in which the snake could not be identified. first aid measures taken prior to hospitalization included ...19968659952
1h, 15n and 13c resonance assignments and secondary structure of group ii phospholipase a2 from agkistrodon piscivorus piscivorus: presence of an amino-terminal helix in solution.1h, 15n and 13c resonance assignments are presented for the group ii phospholipase a2 (pla2) from agkistrodon piscivorus piscivorus. the secondary structure of the enzyme has been inferred from an analysis of coupling constants, interproton distances, chemical shifts, and kinetics of amide exchange. overall, the secondary structure of this pla2 is similar to the crystal structure of the homologous group ii human nonpancreatic secretory phospholipase [scott, d.l., white, s.p., browning, j.l., ros ...19968616268
characterization of the clinical and anatomical pathological changes associated with hepatozoon mocassini infections in unnatural reptilian hosts.laboratory-reared aedes aegypti mosquitoes were employed in the successful transmission of hepatozoon mocassini from a cotton-mouth moccasin (agkistrodon piscivorus leucostoma) to 3 lizard species (sceloporus undulatus, eumeces obsoletus and sceloporus poinsetti). marked to severe lethargy and anorexia developed in the s. undulatus, e. obsoletus and s. poinsetti at 15, 38, and 96 days postinfection (pi), respectively. all 3 lizards developed a leukocytosis and had increased plasma aspartate amin ...19968690537
structural aspects of interfacial adsorption. a crystallographic and site-directed mutagenesis study of the phospholipase a2 from the venom of agkistrodon piscivorus piscivorus.recent genetic and structural studies have shed considerable light on the mechanism by which secretory phospholipases a2 interact with substrate aggregates. electrostatic forces play an essential role in optimizing interfacial catalysis. efficient and productive adsorption of the class i bovine pancreatic phospholipase a2 to anionic interfaces is dependent upon the presence of two nonconserved lysine residues at sequence positions 56 and 116, implying that critical components of the adsorption s ...19979013608
re: pit viper bites: rational management in locales in which copperheads and cottonmouths predominate. 19979088473
lys-49-phospholipases a2 as active enzyme for beta-arachidonoyl phospholipid bilayer membranes.phospholipases a2 containing lys-49 have been reported to be extremely weak or inactive as enzyme. we have recently shown that basic proteins i and ii (bp-i and bp-ii), lys-49-pla2s isolated from the venom of trimeresurus flavoviridis (habu snake), are potent to hydrolyze the arachidonate of 2-arachidonoyl-1-stearoyl-l-3-phosphatidylcholine (aspc) in bilayer vesicles. in order to ensure such enzymatic activity of lys-49-pla2s, two other lys-49-pla2s from different snake venoms, myotoxin ii (from ...19979315278
crystal structure of piratoxin-i: a calcium-independent, myotoxic phospholipase a2-homologue from bothrops pirajai venom.the crystal structure of piratoxin-i (prtx-i) a lys49 homologue isolated from the venom of bothrops pirajai has been determined and refined at 2.8 a to a crystallographic residual of 19.7% (rfree = 29.7%). amino-acid sequence differences between catalytically active phospholipases and prtx-i in the putative ca2+-binding loop, specifically the substitutions tyr28 --> asn, gly32 --> leu and asp49 --> lys, result in an altered conformation of this loop. the analysis of the position of the epsilon-a ...19989723838
malignant peripheral nerve sheath tumor in a water moccasin (agkistrodon piscivorus). 19989580548
crystallization and preliminary diffraction data of a platelet-aggregation inhibitor from the venom of agkistrodon piscivorus piscivorus (north american water moccasin).applaggin (agkistrodon piscivorus piscivorus platelet-aggregation inhibitor) is a potent inhibitor of blood platelet aggregation derived from the venom of the north american water moccasin. the protein consists of 71 amino acids, is rich in cysteines, contains the sequence-recognition site of adhesion proteins at positions 50-52 (arg-gly-asp) and shares high sequence homology with other snake-venom disintegrins such as echistatin, kistrin and trigramin. single crystals of applaggin have been gro ...199910417418
spatial structures of the bradykinin potentiating peptide f from agkistrodon piscivorus piscivoris venom.bradykinin potentiating peptides usually show two different activities, potentiation of bradykinin and inhibition of angiotensin converting enzyme (ace). exceptions of this rule have been found suggesting that both effects occur independently. this study of peptide f by means of nmr spectroscopy shows clearly two different main conformations of the molecule. these different conformations may be the reason for the different activities.199910082165
envenomations.envenomations are uncommon, challenging causes of critical care admissions. this article describes the diagnosis and treatment of envenomations that cause the most critical care admissions in the united states. most are caused by the following animals: rattlesnakes, copperheads, cottonmouths, coral snakes, brown recluse spiders, and bark scorpions.199910331133
primary structure and biological activity of snake venom lectin (apl) from agkistrodon p. piscivorus (eastern cottonmouth).a lectin (apl) was purified from the venom of agkistrodon piscivorus piscivorus (eastern cottonmouth moccasin). apl is a disulfide-linked, homodimeric protein consisting of identical monomers of molecular weight 16,200. native rabbit and human erythrocytes were agglutinated by apl and the activity was found to be calcium-dependent. galactose, lactose, rhamnose and egta strongly inhibited the hemagglutination activity of apl. the complete amino acid sequence determined by edman sequencing of the ...199910484740
phylogeography of the pitviper clade agkistrodon: historical ecology, species status, and conservation of cantils.we used mitochondrial dna sequences from three gene regions and two trnas (nd4, trna-his-ser, 12s, and 16s rdna) to investigate the historical ecology of the new world pitviper clade agkistrodon, with emphasis on the disjunct subspecies of the cantil, a. bilineatus. we found strong evidence that the copperhead (a. contortrix) is basal to its congeners, and that the cottonmouth (a. piscivorus) is basal to cantils. phylogeography and natural history of the living terminal taxa imply that agkistrod ...200010736044
cloning of cdnas encoding c-type lectins from elapidae snakes bungarus fasciatus and bungarus multicinctus.a number of c-type lectins with various biological activities have been purified and characterized from viperidae snake venoms. in contrast, only a few reports could be found in literature concerning the c-type lectins in elapidae snake venoms. based on the published cdna sequences of c-type lectins from viperidae snake venoms, oligonucleotide primers were designed and used to screen the cdna libraries made from the venom glands of bungarus fasciatus and bungarus multicinctus. this allowed the c ...200111600152
purification and characterization of a new rgd/kgd-containing dimeric disintegrin, piscivostatin, from the venom of agkistrodon piscivorus piscivorus: the unique effect of piscivostatin on platelet aggregation.piscivostatin, a novel dimeric disintegrin containing arg-gly-asp (rgd) and lys-gly-asp (kgd) sequences, was isolated from the venom of agkistrodon piscivorus piscivorus. the molecule consisted of two chains designated as the alpha and beta chains, comprising 65 and 68 amino acid residues, respectively. piscivostatin had two binding motifs recognized by platelet glycoprotein iib/iiia (gpiib/iiia), and the biological activity of dimeric disintegrin piscivostatin toward platelet aggregation differ ...200111530017
changes in ca2+ affinity upon activation of agkistrodon piscivorus piscivorus phospholipase a2.changes in the affinity of calcium for phospholipase a2 from agkistrodon piscivorus piscivorus during activation of the enzyme on the surface of phosphatidylcholine vesicles have been investigated by site-directed mutagenesis and fluorescence spectroscopy. changes in fluorescence that occur during lipid binding and subsequent activation have been ascribed to each of the three individual trp residues in the protein. this was accomplished by generating a panel of mutant proteins, each of which lac ...200111258945
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