Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| amino acid sequence and circular dichroism of indian cobra (naja naja naja) venom acidic phospholipase a2. | the full amino acid sequence of the acidic phospholipase a2 from indian cobra (naja naja naja) venom was determined and its tertiary structure examined by circular dichroism (cd). the sequence was aligned with other sequences of secreted phospholipase a2 from snakes of the genus naja, using the progressive alignment method of feng and doolittle (j. mol. evol. (1987) 25, 351-360). the primary sequence of naja naja naja phospholipases a2 shows up to 85% identity with the other acidic naja phosphol ... | 1990 | 2294972 |
| the interaction of phospholipase a2 with phospholipid analogues and inhibitors. | a series of structurally modified phospholipids have been used to delineate the structural features involved in the interaction between cobra venom (naja naja naja) phospholipase a2 and its substrate. special emphasis has been placed on sn-2 amide analogues of the phospholipids. these studies have led to a very potent, reversible phospholipase a2 inhibitor. a six-step synthesis of this compound, 1-palmitylthio-2-palmitoylamino-1,2-dideoxy-sn-glycero-3- phosphorylethanolamine (thioether amide-pe) ... | 1990 | 2303420 |
| characterization of a cytotoxin-like basic protein from the cobra (naja naja naja) venom. | a cytotoxin-like basic protein has been isolated from the venom of the nominate race of cobra (naja naja naja from pakistan) by a single step of high-performance liquid chromatography. the primary structure was determined and consists of 62 amino acid residues in a single polypeptide chain. it is highly similar to that of the cytotoxin-like basic proteins isolated from other naja species, but differs in two of the ss-loop structures from that of cytotoxins. | 1990 | 2311757 |
| proteinaceous inhibitors of phospholipase a2 purified from inflammatory sites in rats. | we have purified two phospholipase a2 inhibitory proteins (37 and 33 kda) from peritoneal fluid of dexamethasone-treated rats. the extracellular phospholipase a2 found in inflammatory sites differed from the exocrine phospholipase a2 in susceptibility to these endogenous inhibitors; both proteins inhibited the activity of the extracellular phospholipase a2 purified from sites of inflammation but did not affect appreciably the activity of either porcine pancreatic or naja naja venom phospholipase ... | 1990 | 2320562 |
| ablation of natural killer cell function by soluble cardiotoxin. | a one-hour preincubation of nonadherent murine spleen cells with a soluble membrane-active cardiotoxin purified from the venom of the thailand cobra naja naja siamensis results in the destruction of natural killer (nk) cell activity against yac-1 target cells in a dose-dependent manner. prior in vivo induction of interferon production by polyinosinic/polycytidylic acid does not avert the cardiotoxin inhibition of nk function. loss of complement-mediated lysis of cells capable of binding an nk-1. ... | 1990 | 2329017 |
| the active site and partial sequence of cobra venom acetylcholinesterase. | about 30% of the primary structure of acetylcholinesterase (ache) from the cobra naja naja oxiana has been determined. the sequence around the serine residue labeled by diisopropylfluorophosphate (dfp) was found to be tvtlfgesagaasvgm which is similar to the active sites of ache from other tissues. the part of the primary structure determined shows 76% identity with ache from torpedo and 42% identity with the drosophila enzyme. a surprisingly large identity (42% in the sequence determined) was f ... | 1990 | 2340076 |
| nonequivalence of alpha-bungarotoxin binding sites in the native nicotinic receptor molecule. | in the native, membrane-bound form of the nicotinic acetylcholine receptor (m-acchr) the two sites for the cholinergic antagonist alpha-bungarotoxin (alpha-bgt) have different binding properties. one site has high affinity, and the m-acchr/alpha-bgt complexes thus formed dissociate very slowly, similar to the complexes formed with detergent-solubilized acchr (s-acchr). the second site has much lower affinity (kd approximately 59 +/- 35 nm) and forms quickly reversible complexes. the nondenaturin ... | 1990 | 2340276 |
| identification of a crotoxin-binding protein in membranes from guinea pig brain by photoaffinity labeling. | crotoxin is a neurotoxic phospholipase a2 capable of blocking synaptic transmission by inhibiting the release of neurotransmitters. the photoaffinity labeling technique was used to identify the neural membrane molecules involved in the binding of crotoxin. a photoactivatable, radioactive derivative of crotoxin was synthesized by reacting crotoxin with n-hydroxysuccinimidyl-4-azidobenzoate and with na[125i]. photoirradiation of synaptosomes from guinea pig brains in the presence of the crotoxin d ... | 1990 | 2341382 |
| leukotriene and prostaglandin production in rat brain synaptosomes treated with phospholipase a2 neurotoxins and enzymes. | beta-bungarotoxin (beta-butx) and notexin cause an irreversible blockade of neurotransmitter release through specific and potent effects at the presynaptic nerve terminal, however, the mechanism of action is uncertain. we examined the effects of beta-butx and notexin on lt and pg production in rat cerebrocortical synaptosomes in order to determine if eicosanoid production might mediate or regulate the pharmacological actions of these phospholipase a2 (pla2) neurotoxins. the effects of the pla2 e ... | 1990 | 2343144 |
| [the effect of calmodulin and chlorpromazine on the activity of phospholipases a2 from various sources]. | the effects of calmodulin and chlorpromazine on purified phospholipase a2 preparations from snake venoms: cobra (naja naja oxiana), echis (ehis multisquamatus) and agkistrodon halys halys, as well as on phospholipases a2 from rat liver mitochondria and human platelets were studied. it was shown that within the concentration range of 1-5 microm calmodulin stimulates the phospholipase activity. chlorpromazine inhibits the activity of these enzymes, the degree of inhibition being different for vari ... | 1990 | 2344456 |
| effect of modification of tyrosine residues in cytotoxin-1 from indian cobra venom. (naja naja naja). | the role of tyrosine residues in the biological activity of cytotoxin-1 was evaluated using n-bromo succinimide. n-bromo succinimide effected the oxidation of tyrosine residues in cytotoxin-1 with an increase in absorption at 260 nm. n-chloro succinimide was ineffective in the oxidation of tyrosine residues in the toxin. oxidation of a single tyrosine residue (at 3.50 equivalents of n-bromo succinimide/mole of the toxin) resulted in complete loss of lethal activity of the toxin. the lytic activi ... | 1990 | 2350359 |
| pattern of acetylcholinesterase activity in the hypothalamus of the cobra, naja naja. | application of acetylcholinesterase (ache) method to the hypothalamus of the cobra naja naja revealed a clearly discernible pattern of activity in the nuclear groups. the magnocellular neurons distributed in various subdivisions showed strong reaction. among the parvocellular groups, intense enzyme activity was observed in the cells of nucleus subfornicalis, nucleus hypothalamicus medialis, dorsal and ventral subdivisions of the nucleus hypothalamicus lateralis and the nucleus mamillaris. the pa ... | 1990 | 2358653 |
| selective cytolysis by a protein toxin as a consequence of direct interaction with the lymphocyte plasma membrane. | two lines of evidence support the concept that cardiotoxin from naja naja siamensis interacts directly with the plasma membrane to produce selective cytolysis of lymphocytes. toxin adsorbed to the wells of microtiter plates retained the ability to lyse murine t-lymphocytes, but lost the ability to destroy natural killer cells, whereas soluble toxin obliterated both cell types. second, toxin covalently coupled to 100-microns-diameter agarose beads, such that endocytosis would be precluded, effect ... | 1990 | 2363180 |
| purification of plasmalogens using rhizopus delemar lipase and naja naja naja phospholipase a2. | bovine heart chogpl (choline glycerophospholipid) and bovine brain etngpl (ethanolamine glycerophospholipid) contain diacyl, alkenylacyl and alkylacyl analogs. purification of plasmalogens was achieved using r. delemar lipase and n. naja naja phospholipase a2 digestion. the r. delemar lipase hydrolyzes the acyl bond at the 1-position of 1,2-diacyl glycerophospholipids. the n. naja naja phospholipase a2 has greater activity with diacyl and alkylacyl than with alkenylacyl glycerophospholipids. the ... | 1990 | 2366631 |
| kinetic and inhibition studies of phospholipase a2 with short-chain substrates and inhibitors. | the action of the phospholipases a2 (pla2s) from naja naja naja, naja naja atra, and crotalus atrox venoms as well as the enzyme from porcine pancreas on a number of short-chain, water-soluble substrates was studied. the inhibition of these enzymes by short-chain phosphonate- and thiophosphonate-containing phospholipid analogues was also examined. the kinetic patterns observed for the action of the venom pla2s on substrates containing phosphocholine head groups all deviated from a classical mich ... | 1990 | 2383571 |
| crystallization and preliminary x-ray diffraction study of neurotoxin-i from naja naja oxiana venom. | crystals of the neurotoxin-i (ntx-i) from the venom of the middle asian cobra naja naja oxiana have been grown by vapour diffusion and dialysis methods. the crystals belong to space group p2(1)2(1)2 with dimension of a = 25.19 a, b = 75.59 a, c = 36.09 a and diffract to 1.9 a resolution. the asymmetric unit contains one molecule (vm = 2.2 a/da). using the molecule of alpha-cobratoxin (ctx) as a starting model for ntx-i structure determination coordinates of c alpha atoms of the ntx-i molecule we ... | 1990 | 2387409 |
| envenoming by the common krait (bungarus caeruleus) and sri lankan cobra (naja naja naja): efficacy and complications of therapy with haffkine antivenom. | in anuradhapura, sri lanka, 5 patients proved to have been bitten by common kraits (bungarus caeruelus) and 2 by sri lankan cobras (naja naja naja) were investigated. in all the cases of krait bite the patients were bitten while they were asleep: local signs were negligible but 4 developed symptoms of systemic envenoming including paralysis, muscle pain and tenderness and abdominal pain. mild myoglobinaemia was found in one case. of the 2 patients bitten by cobras, one developed severe local swe ... | 2017 | 2389328 |
| interactions in red blood cells between fatty acids and either snake venom cardiotoxin or halothane. | phospholipase a2 (pla2) activity enhances snake venom cardiotoxin (ctx)-induced and general anesthetic (halothane)-induced hemolysis of red blood cells. in the case of halothane-induced hemolysis, this effect appears to be related primarily to free fatty acids. in the present study, the interaction between ctxs and halothane and the effects of different free fatty acids on cardiotoxin and halothane-induced hemolysis were examined. the hemolytic actions of halothane and a ctx from naja naja kaout ... | 1990 | 2402762 |
| 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 ... | 1985 | 2410338 |
| antigenic relatedness between phospholipases a2 from naja naja venom and from mammalian cells. | polyclonal antiserum was prepared against phospholipase a2 from naja naja and used to prepare a purified antibody. it cross-reacted with the antigen, and with intracellular mammalian pla2. this antibody was immunoreactive and inhibited the pla2 activity of naja naja and of guinea pig alveolar macrophages or rat lymphocytes. by immunoblotting, this antiserum revealed one band of pla2 from naja naja (14 kda) and 3 bands for guinea pig alveolar macrophages and rat lymphocytes (30, 45 kda and a mino ... | 1987 | 2443388 |
| regulation of gamma-aminobutyric acid/barbiturate receptor-gated chloride ion flux in brain vesicles by phospholipase a2: possible role of oxygen radicals. | preincubation of brain membranes with phospholipase a2 (pla2) has been shown previously to affect the binding characteristics of various recognition sites associated with the gamma-aminobutyric acid (gaba) receptor complex. in the present study, we have investigated the effects of pla2 (from naja naja siamensis venom) on the functional activity of the gaba receptor/chloride ion channel. pla2 (0.001-0.02 u/mg protein) preincubation decreased pentobarbital-induced 36cl- efflux and muscimol-induced ... | 1988 | 2447244 |
| monoclonal antibodies against vipera lebetina venom nerve growth factor cross-react with other snake venom nerve growth factors. | nerve growth factor (ngf) was isolated from the venom of vipera lebetina and was purified to homogeneity as judged by sds gel electrophoresis. the biologically active ngf was used to immunize balb/c mouse, and the spleen cells from immunized mouse were fused with mouse pai myeloma cells. forty-seven hybrid cell lines, secreting monoclonal antibodies to v. lebetina ngf, were isolated and nine of them purified from ascitic fluids. the isolated antibodies define two partially overlapping epitopes o ... | 1987 | 2448608 |
| pharmacological study of phospholipase a2-induced histamine release from rat peritoneal mast cells. | the effect of some drugs on phospholipase a2 (pla2)-induced histamine release from rat peritoneal mast cells was investigated. 1. pla2 (naja naja) caused the release of histamine from rat peritoneal mast cells in a dose related fashion. 2. the release of histamine by pla2 was decreased by the removal of each of calcium and glucose from the reaction medium (tyrode's solution). 3. p-bromophenacyl bromide and mepacrine, pla2 inhibitors, inhibited the release of histamine caused by pla2. 4. cinnariz ... | 1989 | 2482349 |
| assessment of the role of tryptophan residues in phospholipase a2 by fluorescence quenching. | tryptophan (trp) fluorescence of two phospholipases a2 (pla2) from naja naja atra and naja nigricollis snake venoms was quenched by acrylamide and iodide. trp residues in n. naja atra pla2 were equally accessible to acrylamide and iodide. iodide quenching studies indicate that there are two classes of trp fluorophores in n. nigricollis cms-9. the accessible class consists of trp-18 and trp-19. removal of the n-terminal octapeptide caused a perturbation of the micro-environment of the trp residue ... | 1989 | 2489051 |
| studies on the status of lysine residues in phospholipase a2 from naja naja atra (taiwan cobra) snake venom. | phospholipase a2 (pla2) from naja naja atra (taiwan cobra) snake venom was subjected to lysine modification with trinitrobenzene sulphonic acid (tnbs), and two major trinitrophenylated (tnp) derivatives, tnp-1 and tnp-2, were separated by h.p.l.c. tnp-1 contained only one tnp group on lys-6 and showed a marked decrease in enzymic activity, but still retained 45% of the lethal toxicity. both lys-6 and lys-65 were modified in tnp-2, and modification of lys-65 caused a further reduction of the leth ... | 1989 | 2511834 |
| identification of a locality in snake venom alpha-neurotoxins with a significant compositional similarity to marine snail alpha-conotoxins: implications for evolution and structure/activity. | alpha-neurotoxins from elapid snake venoms and alpha-conotoxins from marine snails bind specifically and with high affinity to nicotinic cholinoceptors. although both types of toxin are polypeptides, there is more than a fourfold difference in size between the two and no clear sequence homology is evident. a systematic computer search of the three-dimensional structure of erabutoxin b (an alpha-neurotoxin from the false sea snake laticauda semifasciata) was performed to identify the locality tha ... | 1989 | 2514275 |
| factors in snake venoms that increase capillary permeability. | capillary permeability increasing (cpi) activity is a phenomenon of the microvasculature caused by many agents such as snake venoms, histamine, 5-hydroxytryptamine (5-ht), prostaglandins and leukotrienes. since no systematic study has been done to determine what components of snake venom cause cpi activity, a cpi factor from naja naja atra (taiwan cobra) venom was isolated using intravenous injections of evan's blue dye as the indicator of increased permeability and the factor's properties were ... | 1989 | 2576052 |
| amino acid sequences of cytotoxin-like basic proteins derived from cobra venoms. | amino acid sequences of cytotoxin-like basic proteins (clbps), purified from the venoms of formosan cobra (naja naja atra) and indian cobra (naja naja), were reinvestigated. the determined sequences differed from those reported previously by takechi et al. [(1985) biochem. int. 11, 795-802; (1987) biochem. int. 14, 145-152]. the sequence of clbps at residues 25-30 was found to be hydrophilic as compared with those of cytotoxins. the difference in the hydrophobicity of this region might be respon ... | 1989 | 2583280 |
| neutrophil-dependent, oxygen-radical mediated lung injury associated with acute pancreatitis. | cerulein-induced acute pancreatitis in rats is associated with a reversible lung injury that is characterized by alveolar capillary endothelial-cell injury, increased microvascular permeability, interstitial edema formation, and intraalveolar hemorrhage and fibrin deposition. the role of mediators in this injury was analyzed using gravimetric data, microvascular permeability indices, electron microscopy, and a quantitative morphometric analysis. neutrophil depletion induced by a specific antibod ... | 1989 | 2589887 |
| pulmonary responses to phospholipase a2 in the perfused guinea pig lung. | we examined the effect of phospholipase a2 (pla2; naja naja) challenge on pulmonary hemodynamics, airway constriction, and fluid filtration in isolated ringer-perfused guinea pig lungs. intratracheal pla2 (10-100 u) produced dose-dependent increases in pulmonary arterial pressure, intratracheal pressure, and lung weight, although intravenous pla2 administration had no effect on monitored variables. morphological features indicative of airway constriction and pulmonary edema were observed by ligh ... | 1989 | 2606858 |
| role of ca2+ in the substrate binding and catalytic functions of snake venom phospholipases a2. | phospholipases a2 are classified into two groups, i and ii, according to differences in the polypeptide-chain length and the intramolecular-disulfide bondings. the effects of ca2+ on the kinetic parameters for the hydrolysis of monodispersed and micellar phosphatidylcholines, catalyzed by a cobra (naja naja atra) enzyme (group i) and by mamushi (agkistrodon halys blomhoffii) and habu (trimeresurus flavoviridis) enzymes (group ii), were studied by the ph-statassay method at 25 degrees c, ph 8.0-8 ... | 1989 | 2606904 |
| the anticoagulant activity of malayan cobra (naja naja sputatrix) venom and venom phospholipase a2 enzymes. | malayan cobra (naja naja sputatrix) venom was found to exhibit an in vitro anticoagulant activity that was much stronger than most common cobra (genus naja) venoms. the most potent anticoagulants of the venom are two lethal phospholipase a2 enzymes with pi's of 6.15 and 6.20, respectively. the anticoagulant activity of the venom is due to the synergistic effect of the venom phospholipase a2 enzymes and polypeptide anticoagulants. bromophenacylation of the two phospholipase a2 enzymes reduced the ... | 1989 | 2619749 |
| amino acid sequence of nerve growth factor purified from the venom of the formosan cobra naja naja atra. | nerve growth factor (ngf) was isolated from the venom of the formosan cobra (naja naja atra). the amino acid sequence was determined by a combination of conventional methods. the total number of amino acid residues was 116, giving a molecular mass of 13,057 da. the sequence was identical with that deduced from the nucleotide sequence of an ngf cdna from the venom gland of naja naja siamensis, reported by selby et al. [j. neurosci. res., 18, 293-298 (1987)]. | 1989 | 2619756 |
| phospholipase a2 from cobra (naja naja naja) venom. primary structure and subspecies variation. | the primary structure of phospholipase a2 of the major race of indian cobra has been determined. together with previous data on other subforms, it establishes subspecies variations at no less than 20 of the 119 positions in the protein. these variations are large, not only in number but in several cases also regarding properties of the residues involved. nevertheless, all structures are compatible with largely unaltered enzyme properties. | 1989 | 2626425 |
| [major complement inhibiting factors from the venom of the central asian cobra naja naja oxiana]. | the properties of two anticomplementic factors isolated by cm-sepharose chromatography from the basic non-adsorbed on deae-sepharose fraction of the central asian cobra naja naja oxiana venom, were studied. of these three factors (cfb-i, cfb-ii and cfb-iii) the latter had been characterized earlier. cfb-i was shown to be a protein with an n-terminal asp and a molecular mass of about 39 kda (data from gel chromatography); its content in the venom is 3.6 mg/g of dry venom. the protein inhibits mai ... | 1989 | 2627558 |
| interaction of central asian cobra (naja naja oxiana eichwald) venom cytotoxins with phospholipase d. | effect of cytotoxins from the venom of naja naja oxiana eichwald on the hydrolytic function of phospholipase d has been further analysed. cytotoxins in the absence of ca2+ activated the enzyme, whereas in its presence they inhibited it. inhibition is shown to be related to the interaction of cytotoxins with the enzyme which blocks the absorption of the enzyme at the surface of the substrate phase. synergism in the action of cytotoxin and phospholipase d was not noticed. | 1989 | 2628264 |
| effects of divalent cations on snake venom cardiotoxin-induced hemolysis and 3h-deoxyglucose-6-phosphate release from human red blood cells. | at a low concentration of naja naja kaouthia cardiotoxin (3 microm) ca2+, sr2+ and ba2+ (2 mm), had little to no effect on 3h-deoxyglucose-6-phosphate (3h-dglu-6-p) or hemoglobin release. at higher concentrations of n. n. kaouthia cardiotoxin (greater than or equal to 10 microm), ca2+ (2 mm), but not sr2+ or ba2+, significantly enhanced 3h-dglu-6-p and hemoglobin release. mn2+ (2 mm) almost completely inhibited 3h-dglu-6-p release and hemolysis at both the 3 microm and 10 microm concentrations o ... | 1989 | 2629171 |
| [complement-inhibiting acidic factors from the venom of central asian cobra naja naja oxiana]. | two anticomplementic factors isolated from the venom of the central asian cobra naja naja oxiana by chromatography on deae-sepharose cl-6b and subsequent gel filtration on sephacryl s-200 were studied. of these, five factors (cfa-ia, cfa-ib, cfa-ic, cfa-iia and cfa-iib), cfa-ib had been characterized earlier, while cfa-ia was assigned to a previously identified h-cof factor. it was shown that cfa-ic has a molecular mass of 3900 da; its content in the venom amounts to 2.6 mg/g of dry venom. this ... | 1989 | 2633805 |
| comparison of tensilon and antivenom for the treatment of cobra-bite paralysis. | we prospectively compared the ability of anti-venom and edrophonium (tensilon) to improve paralytic symptoms in 8 patients envenomed by the philippine cobra (naja naja philippinensis). twenty, 50 or 100 ml of philippine cobra antivenom were administered in a double-blind fashion by constant intravenous infusion over 30 min. even the largest dose of antivenom failed to produce marked improvement within 2 h, though enzyme-linked immunosorbent assays and neutralization tests demonstrated that it po ... | 2013 | 2694492 |
| continuous spectrophotometric assay of phospholipase a2 activity hydrolyzing plasmalogens using coupling enzymes. | we developed a continuous spectrophotometric assay of the phospholipase a2 activity specific for choline plasmalogen using rat liver lysoplasmalogenase and horse liver alcohol dehydrogenase as coupling enzymes and naja naja venom phospholipase a2 as a source of the phospholipase a2 activity. in these coupling reactions, choline lysoplasmalogen is hydrolyzed by lysoplasmalogenase to glycerophosphocholine and free aldehyde. the free aldehyde is quantitatively converted to alcohol by alcohol dehydr ... | 1989 | 2712287 |
| do chemical modifications dissociate between the enzymatic and pharmacological activities of beta bungarotoxin and notexin? | we have measured enzymatic, hemolytic and anticoagulant activities, lethal potencies and effects on contractions of the phrenic nerve-diaphragm preparation, by chemically modified derivatives of beta bungarotoxin (beta butx) and notexin, two presynaptically acting toxins which have pla2 activity. the following chemical modifications of beta butx were tested: alkylation and methylation of histidine 48, alkylation of tryptophan 19, sulfonylation of tyrosine 68, oxidation of methionines 6 and 8, se ... | 1989 | 2718187 |
| factors influencing the hemolysis of human erythrocytes by cardiotoxins from naja naja kaouthia and naja naja atra venoms and a phospholipase a2 with cardiotoxin-like activities from bungarus fasciatus venom. | the effects of red blood cell age and incubation conditions (temperature, divalent cation type and concentration, ph and glucose) on hemolysis induced by cardiotoxin fractions from naja naja atra and naja naja kaouthia venoms, a phospholipase a2 with cardiotoxin-like activities from bungarus fasciatus venom and bee venom phospholipase a2 were examined. hemolysis by the snake venom toxins was dependent on red blood cell age (aged more susceptible than fresh) and the temperature of incubation (37 ... | 1989 | 2718193 |
| roles of mast cells and pmn leukocytes in cardiotoxin-induced rat paw edema. | cardiotoxin, isolated from the venom of naja naja atra, was found to cause rat hind-paw edema in a dose-dependent manner. this edematous response was significantly suppressed by pretreatment with diphenhydramine, methysergide or compound 48/80, which reduced the tissue histamine content. polymorphonuclear (pmn) leukocyte infiltration appeared within 1 h and had accumulated markedly in the rat paw 3-6 h after subplantar injection of cardiotoxin. methotrexate pretreatment significantly reduced not ... | 1989 | 2721549 |
| hemolytic activity of thionin from pyrularia pubera nuts and snake venom toxins of naja naja species: pyrularia thionin and snake venom cardiotoxin compete for the same membrane site. | pyrularia thionin (p. thionin) is a strongly basic peptide of 47 amino acids which is hemolytic, cytotoxic and neurotoxic. it shows the greatest hemolytic activity toward human erythrocytes. rabbit, guinea pig and pig erythrocytes show decreasing activity in that order, and little or no activity is shown with sheep, horse, cow or mouse erythrocytes. crotalus venoms are inactive, but the venoms from naja naja atra, naja naja ceylonicus and naja naja melanoleuca and, more specifically, cardiotoxin ... | 1989 | 2749751 |
| a prostaglandin oligomeric derivative inhibits activities of phospholipase and protease: a possible mechanism of membrane protection during ischemia. | a prostaglandin oligomeric derivative was synthesized by alkaline treatment of prostaglandin e1. this compound protected the perfused rat heart from global ischemia. this compound was found to inhibit several lipolytic and proteolytic enzymes in vitro. when phospholipase a2 from naja naja venom was used as an enzyme and phosphatidylcholine was used as a substrate, 50 per cent inhibition was achieved at 50 microm of the prostaglandin derivative. when trypsin and casein were used as enzyme and sub ... | 1989 | 2752536 |
| isolation and characterization of an acidic lethal phospholipase az from malayan cobra (naja naja sputatrix) venom. | an acidic, lethal phospholipase az was purified to electrophoretic homogeneity from the venom of the malayan cobra (naja naja sputatrix). the enzyme has an isoelectric point of 5.58, a molecular weight of 12000, and a medium lethal dose (ld50) of 0.86 micrograms/g in mice by intravenous injection. the enzyme also exhibited weak anticoagulant and edema-forming activities. the amino acid composition of the enzyme is similar to those of other cobra venom phospholipases az. | 1989 | 2764979 |
| [a factor from the venom of the central asiatic cobra naja naja oxiana, which inactivates component c4 of human complement]. | an acid glycoprotein (mol. m. 60 kda) containing 6 sialic acid residues and n-terminal thr was isolated from the venom of the central asian cobra naja naja oxiana. the protein has an anticomplementary activity selectively inactivating of the c4 component of the human complement. this factor (cfa-ib) binds c4 with ki = 0.27 +/- 0.13 microm and then irreversible inactivates it with a rate constant k = 0.75 +/- 0.25 min-1. membrane bound c4b restores its ability of cfa-ib binding. this binding hind ... | 1989 | 2770721 |
| purification and characterization of a myotoxic phospholipase a2 from indian cobra (naja naja naja) venom. | a major phospholipase a2 (nn-xiii-pla2) which constitutes 20% of the whole naja naja naja venom was purified to homogeneity on cm-sephadex c-25 column chromatography. nn-xiii-pla2 is a basic protein with a mol. wt of 11,200 by sds-page. this enzyme has low enzymatic activity but is more toxic to mice than the whole venom. the ld50 value (i.p.) of nn-xiii-pla2 is 2.4 mg/kg body weight (whole venoms ld50 is 2.8 mg/kg body weight). it induces neurotoxic-like signs in experimental animals. it induce ... | 2009 | 2781585 |
| immunological relationships of phospholipase a2 neurotoxins from snake venoms. | polyclonal rabbit antisera were raised against ten snake phospholipase a2 neurotoxins and one snake phospholipase a2 cytotoxin. immunological cross-reactivities between these toxins, two other snake phospholipase a2 enzymes and pancreatic phospholipase a2 were studied using elisa technology. all snake phospholipase a2 neurotoxins fell into two main antigenic classes. one antigenic class was composed of all the elapid toxins tested (textilotoxin, taipoxin, notexin, pseudexin and beta-bungarotoxin ... | 1989 | 2799839 |
| step-wise thermal denaturation of cobrotoxin, a snake venom neurotoxin from naja naja atra: a proton nuclear magnetic resonance study. | temperature dependence of proton nuclear magnetic resonance spectra has been followed for cobrotoxin, a postsynaptic neurotoxin from naja naja atra venom. several aromatic amino-acid residues, including the functionally essential trp-29 located at the tip of the central loop of the molecule, have been found to undergo a thermal structural transition above the global thermal denaturation temperature. it is suggested that a local structure around these residues behaves somehow independently of the ... | 1989 | 2803517 |
| sequence characterization of venom toxins from thailand cobra. | several toxins with distinct pharmacological properties were isolated from the venom of thailand cobra (naja naja siamensis) by cation-exchange chromatography. two neurotoxins and one basic toxin with cardiotoxic activity were further purified and sequenced. the neurotoxins characterized were closely similar to the previously reported long- and short-chain neutrotoxins. the complete sequences of one minor neurotoxin and one cardiotoxin analogue were determined with the automatic protein sequence ... | 1989 | 2807733 |
| purification and characterization of an endogenous protein modulator of radioligand binding to "peripheral-type" benzodiazepine receptors and dihydropyridine ca2+-channel antagonist binding sites. | acidified extracts of rat antral stomach chromatographed on octadecylsilane cartridges contained material that inhibited the binding of [3h]ro 5-4864 (4'-chlorodiazepam) and [3h]nitrenidipine to "peripheral-type" benzodiazepine receptors and dihydropyridine ca2+-channel antagonist binding sites respectively. this material reduced the apparent affinities of both radioligands without significantly affecting the maximum number of binding sites. in contrast, the binding of [3h]diazepam, [3h]ro 15-17 ... | 1988 | 2829915 |
| a comparative study of cobra (naja) venom enzymes. | 1. the l-amino acid oxidase, hyaluronidase, alkaline phosphomonoesterase, protease, phosphodiesterase, acetylcholinesterase, phospholipase a and 5'-nucleotidase activities of 47 samples of venoms from all the six species of cobra (naja), including five subspecies of naja naja, were examined. 2. the results demonstrated interspecific differences in the venom contents of phospholipase a, acetylcholinesterase, hyaluronidase and phosphodiesterase. these differences in venom enzyme contents can be us ... | 1988 | 2854766 |
| adrenergic receptors of isolated snake atria. | cardiac adrenergic receptors in snakes were examined using an isolated atria preparation of naja naja and ptyas korros. treatments included an examination of the atrial responses to selective alpha- and beta-adrenergic agonists and antagonists. in both species, both phenylephrine and isoproterenol produced dose-dependent increases in the atrial beating rate and tension. phenylephrine-induced increases were characterized with a high affinity and low affinity components. these positive chronotropi ... | 1985 | 2861969 |
| induction of alveolar epithelial injury by phospholipase a2. | severe damage to the alveolar type i epithelial cell is a characteristic morphological feature of lung injury due to numerous cases. it is postulated that excess phospholipase a2 (pla2) activity might be responsible for these changes, as one of the naturally occurring products of this enzyme, lysophosphatidylcholine (lysopc) has been shown to cause selective injury to the type i pneumonocyte when it is instilled into the lower air spaces of the lung. to further investigate this potential mechani ... | 1989 | 2917929 |
| the role of phospholipase in host cell penetration by toxoplasma gondii. | phospholipase a2 (pla2) plays an important pathogenic role in infections caused by several microorganisms and has been implicated in host cell invasion. the mechanism of host cell penetration by the intracellular protozoan toxoplasma gondii involves several steps; we have investigated the role of pla2 in cellular invasion by the tachyzoite stage of this parasite. we assayed t. gondii invasion of human fibroblast monolayers by measurement of the selective incorporation of 3h-uracil into growing i ... | 1989 | 2919724 |
| uncoupling of cholinergic synaptic vesicles by the presynaptic toxin beta-bungarotoxin. | the effect of the presynaptic neurotoxin beta-bungarotoxin (beta-butx) on the acetylcholine (ach) storage system of synaptic vesicles isolated from the electric organ of torpedo californica was studied. the toxin can totally inhibit active transport of [3h]ach by the vesicles in a ca2+-, time-, and concentration-dependent manner. correlated with these effects is a 50-60% stimulation of the vesicle proton-pumping atpase activity. the beta-butx-mediated transport inhibition and atpase stimulation ... | 1986 | 2943872 |
| pancreatic phospholipase a2: isolation of the human gene and cdnas from porcine pancreas and human lung. | oligonucleotide probes synthesized using the published protein sequence for porcine pancreatic phospholipase a2 (pla2; puijk et al., 1977), were used to screen a cdna library made from porcine pancreas. one resulting clone which encoded the entire porcine pla2 enzyme was then used to screen various human cdna and gene libraries. a 562-bp cdna clone from human lung and two overlapping genomic clones encoding the identical transcript were obtained. these clones encoded a 126-residue peptide corres ... | 1986 | 3028739 |
| a novel cleavage product of human complement component c3 with structural and functional properties of cobra venom factor. | the generation of two cleavage products of human c3, termed c3o and c3p, by incubation with a c3-cleaving protease isolated from cobra venom (naja naja siamensis) is described. the venom protease removes the c3p fragment (mr approximately 33,000) from the c3dg region of the c3 alpha-chain. the major cleavage fragment c3o (mr approximately 140,000) contains the unaltered beta-chain of c3 and two alpha-chain-derived polypeptides of mr approximately 29,000 and mr approximately 38,000, respectively. ... | 1988 | 3045125 |
| phospholipase a2 activity associated with synovial fluid cells. | high activity of phospholipase a2 (pla2) has been detected in synovial fluids (sf) in inflammatory arthritides. since the source(s) of sf pla2 has not been identified, we tested pla2 content in sf cells obtained from 11 sf. cell sonicates were prepared at 5 x 10(6) cells/ml. in the supernatants of the sonicated sf cells (n = 11), pla2 activity ranged from 38-755 u/ml, mean 368 +/- 243 (sd) u/ml, compared to 5-64 u/ml, mean 31 +/- 15 (sd) u/ml in sonicates of normal peripheral blood pmn (n = 5) ( ... | 1988 | 3050083 |
| evaluation of venom extracts from the cobra snakes (naja naja) of three different weights and size groups. | 2010 | 3100829 | |
| 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 ... | 1987 | 3109429 |
| enzymatic hydrolysis of short-chain lecithin/long-chain phospholipid unilamellar vesicles: sensitivity of phospholipases to matrix phase state. | short-chain lecithin/long-chain phospholipid unilamellar vesicles (sluvs), unlike pure long-chain lecithin vesicles, are excellent substrates for water-soluble phospholipases. hemolysis assays show that greater than 99.5% of the short-chain lecithin is partitioned in the bilayer. in these binary component vesicles, the short-chain species is the preferred substrate, while the long-chain phospholipid can be treated as an inhibitor (phospholipase c) or poor substrate (phospholipase a2). for phosph ... | 1987 | 3122829 |
| purification and characterization of four monofluorescein cobra alpha-toxin derivatives. | we labeled cobra-alpha-toxin (naja naja siamensis 3) with near stoichiometric quantities of fluorescein isothiocyanate. to reduce labeling of the hyperreactive n epsilon-lysine 23, the alpha-toxin was modified reversibly with citraconic anhydride before fluorescein labeling. the citraconic anhydride was later removed with strong acid, and four of the six possible monofluorescein alpha-toxin derivatives were isolated by isoelectric focusing on an immobilized ph gradient. thermolysin digestion and ... | 1988 | 3125169 |
| site-specific epsilon-nh2 monoacylation of pancreatic phospholipase a2. 2. transformation of soluble phospholipase a2 into a highly penetrating "membrane-bound" form. | long-chain lecithins present in bilayer structures like vesicles or membranes are only very poor substrates for pancreatic phospholipases a2. this is probably due to the fact that pancreatic phospholipases a2 cannot penetrate into the densely packed bilayer structures. to improve the weak penetrating properties of pancreatic phospholipases a2, we prepared and characterized a number of pancreatic phospholipase a2 mutants that have various long acyl chains linked covalently to lys116 in porcine an ... | 1988 | 3130102 |
| binding of a curarimimetic toxin from cobra venom to the nicotinic acetylcholine receptor. interactions of six biotinyltoxin derivatives with receptor and avidin. | we have reacted n-hydroxysuccinimidyl biotin with the principal curarimimetic toxin in naja naja siamensis venom, biotinylating each of the five lysine residues and the n-terminal isoleucine. the six monobiotinyl-toxins were isolated by ion-exchange chromatography, and the residue modified in each was identified by peptide mapping and amino acid analysis. we evaluated the role of each lysine in the binding of toxin to the acetylcholine receptor by measuring the affinity of each biotinyltoxin for ... | 1985 | 3161881 |
| higher order structure of chloroplastic 5s ribosomal rna from spinach. | the secondary and tertiary structure of chloroplastic 5s ribosomal rna from spinach was investigated by the use of several chemical and enzymatic structure probes. the four bases were monitored at one of their watson-crick base-pairing positions with dimethyl sulfate [at a(n1) and c(n3)] and with 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate [at g(n1) and u(n3)]. position n7 of purines was probed with diethyl pyrocarbonate (adenines) and with dimethyl sulfate (guanines) ... | 1988 | 3167011 |
| bites by the philippine cobra (naja naja philippinensis): prominent neurotoxicity with minimal local signs. | we studied 39 patients envenomed by the philippine cobra (naja naja philippinensis). neurotoxicity occurred in 38 cases and was the predominant clinical feature. respiratory paralysis developed in 19 patients, and was often rapid in onset--in 3 cases apnea occurred within 30 min of the bite. there were 2 deaths, both in patients who were moribund upon arrival at the hospital. three patients developed necrosis, and 14 individuals with systemic symptoms had no local swelling. both cardiotoxicity a ... | 1988 | 3177741 |
| [modulation of the m-cholinergic reaction by the venom of the central asian cobra (naja naja oxiana)]. | the effect of the central asian cobra's (naja naja oxiana) poison upon cholinergic response of isolated small intestine was studied in the wistar rats. the effect involved a significant activation by 30-70 per cent of m-cholinergic response in the type of "noncompetitive" interaction. the modulating effect of the poison is supposed to occur due to changes in cytoplasmatic membrane. | 1988 | 3181518 |
| 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 |
| role of the n-terminal region in phospholipases a2 from naja naja atra (taiwan cobra) and naja nigricollis (spitting cobra) venoms. | the n-terminal alpha-amino groups of two phospholipases a2 (pla2) from naja naja atra and naja nigricollis venoms were selectively modified with trinitrobenzene sulfonic acid, and the modified derivatives were separated by high performance liquid chromatography (hplc). trinitrophenylated (tnp) derivatives contained only one tnp group in the alpha-amino group of asn-1 and showed a marked decrease in enzymatic activity. pla2 enzymes were cleaved with cnbr, and the n-terminal octapeptide was separa ... | 1988 | 3188062 |
| purification and characterization of a lethal protein with phospholipase a1 activity from the hornet (vespa basalis) venom. | the hornet, vespa basalis, is one of the most dangerous species of wasps found in taiwan. the insect is aggressive and its venom is highly toxic. by gel filtration on a fractogel tsk hw 50 column followed by cation-exchange chromatography on cm-trisacryl m, a lethal protein was purified from the venom. it has a molecular mass of about 32 kda and an i.v. ld50 value of 0.32 micrograms/g mouse. the toxin is capable of catalyzing the hydrolysis of emulsified phospholipids but not sphingomyelin. anal ... | 1988 | 3196744 |
| antigenic relationships and relative immunogenicities of venom proteins from six poisonous snakes of thailand. | venoms from naja naja siamensis, ophiophagus hannah, bungarus fasciatus, vipera russelli, calloselasma rhodostoma and trimeresurus albolabris have been studied by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. the immunoblots were stained with rabbit homologous and heterologous antibodies. in general, the higher the mol. wt the protein the higher the immunogenicity although two proteins with mol. wts of 23,000 and 25,000 from o. hannah venom are extraordin ... | 1988 | 3201490 |
| [studies of complex lipids. synthesis of ionophore derivatives of diphosphatidylglycerol (cardiolipin)]. | synthesis of cardiolipin analogues containing an ionophore residue in the fatty acid moiety is described. the ionophore, dibenzo-18-crown-6, has been incorporated into second position of the glycerol residue by acylating mono- and dilysocardiolipin with a modified fatty acid anhydride. lyso-derivatives of cardiolipin have been prepared by enzymatic hydrolysis of beef heart cardiolipin by snake venom phospholipase a2 (naja naja oxiana). | 2011 | 3219123 |
| edema-inducing activity of phospholipase a2 purified from human synovial fluid and inhibition by aristolochic acid. | a neutral-active, ca2+-dependent phospholipase a2 (pla2) purified 11,000-fold from human synovial fluid (hsf) induced edema when injected into the mouse foot pad. the edema produced by hsf-pla2 was dose-dependent and was positively correlated with the dose-dependent in vitro expression of pla2 activity. maximum edema was achieved within 45 min after the injection and persisted for at least 6 h. aristolochic acid [8-methoxy-6-nitrophenanthro(3,4-d)-1,3-dioxole-5-carboxylic acid], a major chemical ... | 1988 | 3220517 |
| oral toxicity of central asian cobra (naja naja oxiana eichwald) venom and its fractions to adult blowflies parasarcophaga ruficornis fabricius. | 1988 | 3248836 | |
| tourniquet application after cobra bite: delay in the onset of neurotoxicity and the dangers of sudden release. | the effects of tourniquet application were prospectively studied in 36 hospitalized patients who developed neurotoxic symptoms after bites by the philippine cobra (naja naja philippinensis). tourniquets had been applied in 94% of cases and delayed the onset of symptoms. four patients were asymptomatic prior to the release of their tourniquet and in 11 patients symptoms worsened precipitously. most importantly, 4 patients developed complete respiratory paralysis requiring artificial ventilation o ... | 1988 | 3275141 |
| lipid-induced changes in the secondary structure of snake venom cardiotoxins. | the secondary structures of three snake venom cardiotoxins (from hemachatus hemachatus, naja naja atra, and naja naja naja), in aqueous solution and in a lipid-bound form, were investigated by fourier-transform infrared spectroscopy. the conformation-sensitive protein infrared bands in the amide i region were analyzed using deconvolution and band-fitting procedures. the spectra of the three cardiotoxins in aqueous buffer are very similar; they indicate a high content of both antiparallel beta-sh ... | 1988 | 3335526 |
| effect of phospholipids on fluorescence polarization and lifetimes of fluorescein-labeled phospholipase a2. | phospholipids and divalent metal ions induce changes in the fluorescence polarization of fluorescein-labeled phospholipase a2 from the indian cobra (hazlett, t.l. and dennis, e.a. (1985) biochemistry 24, 6152-6158) which may be indicative of enzyme aggregation. lifetimes and rotational correlation times of the conjugate in the presence of these and other ligands are now reported. the correlation times of monomeric phospholipase a2 were shorter than expected for a hydrated, 13,000 molecular weigh ... | 1988 | 3337833 |
| tryptophan residue essential for activity of naja naja atra phospholipase a2. | when naja naja atra phospholipase a2, which contains three tryptophan residues at the 18th, 19th, and 61st positions, was oxidized with n-bromosuccinimide at ph 4.0, its activity decreased in a convex manner with increase in the extent of oxidation of tryptophan residues. the curve shape showed that the tryptophan residue oxidized last is most responsible for the activity. the order of accessibilities of the three tryptophan residues, which was analyzed according to the method reported previousl ... | 1988 | 3360757 |
| amino-acid sequences of four cytotoxins (cytotoxins i, ii, iii and iv) purified from the venom of the thailand cobra, naja naja siamensis. | four cytotoxins, designated as cytotoxins i, ii, iii and iv, were isolated from the venom of the thailand cobra (naja naja siamensis) by gel filtration on sephadex g-75 followed by cm-cellulose chromatography. the amino-acid sequences were determined by a combination of conventional methods. cytotoxins i, ii, iii and iv were each composed of 60 amino-acid residues and their molecular weights were calculated to be 6693, 6646, 6709 and 6739, respectively. the amino-acid sequences were compared wit ... | 1988 | 3365434 |
| a role for acetylcholine receptors in the fusion of chick myoblasts. | the role of acetylcholine receptors in the control of chick myoblast fusion in culture has been explored. spontaneous fusion of myoblasts was inhibited by the nicotinic acetylcholine receptor antagonists alpha-bungarotoxin, naja naja toxin and monoclonal antibody mcab 5.5. the muscarinic antagonists qnb and n-methyl scopolamine were without effect. atropine had no effect below 1 microm, where it blocks muscarinic receptors; at higher concentrations, when it blocks nicotinic receptors also, atrop ... | 1988 | 3372592 |
| lipid-induced aggregation of phospholipase a2: sucrose density gradient ultracentrifugation and crosslinking studies. | the aggregation behavior of cobra venom (naja naja naja) phospholipase a2 in the presence of lipids and ca2+ was examined using ultracentrifugation and crosslinking techniques. velocity sedimentation experiments were performed in sucrose gradients. the sedimentation coefficients of the cobra phospholipase a2 and various controls, including bovine serum albumin (bsa), malate dehydrogenase, carbonic anhydrase and pancreatic phospholipase a2, were calculated both in the presence and absence of liga ... | 1988 | 3382690 |
| toxicity of central asian cobra (naja naja eichwald) venom and its components to the larvae of blowfly parasarcophaga ruficornis fabr. | 1988 | 3397115 | |
| probing the role of substrate conformation in phospholipase a2 action on aggregated phospholipids using constrained phosphatidylcholine analogues. | phospholipase a2s hydrolyze aggregated phospholipid substrates much more rapidly than dispersed monomeric ones. whether this is a consequence of interface-associated conformational changes of the enzyme or of the substrate, or of both, remains a key question in lipid enzymology. this problem is addressed herein using a rationally designed probe of substrate conformation. (1,3/2)-1-o-(phosphorylcholine)-2,3-o-dihexanoylcyclopentane-1,2,3 -triol is a novel short chain phosphatidylcholine analogue ... | 2012 | 3417646 |
| enzymatic activities of malayan cobra (naja naja sputatrix) venoms. | the enzymatic activities of four samples of malayan cobra venom were investigated. there was significant variation in the contents of l-amino acid oxidase, alkaline phosphomonoesterase, acetylcholinesterase, phospholipase a, 5'-nucleotidase and hyaluronidase. the phosphodiesterase content was, however, constant. storage of the lyophilized venom powder at 25 degrees c for 1 month did not affect the enzymatic activities. the venom enzymatic activities were generally also stable at 4 degrees c in 0 ... | 1987 | 3433296 |
| contracture induction by snake venom cardiotoxin in skeletal muscle from humans and rats. | contracture responses to cardiotoxin (ctx) from naja naja kaouthia venom were investigated in rat and human skeletal muscle of similar fiber type distribution to determine species differences in mechanism of action. rat diaphragm strips and human vastus lateralis preparations were directly stimulated in a tissue bath. the calcium dependence of toxin action, synergism between ctx and phospholipase a2 (pla2) activity and roles of na+ + k+-atpase activity and the sarcoplasmic reticulum ca2+ stores ... | 1987 | 3433297 |
| effects of cardiotoxin d from naja naja siamensis snake venom upon murine splenic lymphocytes. | cardiotoxin d from naja naja siamensis is cytotoxic to t-lymphocytes above 150 femtomoles/10(6) cells. equivalent lysis of macrophages or b-lymphocytes requires at least 1000 times more toxin. reduction and carboxamidomethylation of cardiotoxin d does not effect t cell lysis. at higher toxin concentrations, 50% t-cell lysis occurs within 10 min. splenocytes cultured with mitogens are up to five times more susceptible to toxin than unstimulated cells. cardiotoxin d may directly disrupt the plasma ... | 1987 | 3433298 |
| partial sequence of hemoglobin from cobra (naja naja naja). | hemoglobin from the cobra snake, naja naja naja, was isolated and its chains separated on a cm-cellulose column. the separation profile revealed an alpha and two beta chains having the molar proportions of [alpha]2[beta 1]1[beta 2]1. the n-terminal amino acid sequence of the intact chains and of the cnbr peptides were carried out. the beta 2 chain was found to be heterogeneous comprising a minor component amounting to 11%. this later showed changes at two positions 9 and 14 in the first 30 resid ... | 1987 | 3447643 |
| nicotinic acetylcholine receptor contains multiple binding sites: evidence from binding of alpha-dendrotoxin. | we have studied the stoichiometry of the binding of the long alpha-neurotoxins from the venom of dendroaspis viridis (alpha-dendrotoxin) and naja naja siamensis (alpha-cobratoxin) to the membrane-bound acetylcholine receptor (acchor) from torpedo californica electric organ. the number of toxin molecules bound to one acchor molecule was determined by simultaneous-quantitative gas-phase microsequencing of all the amino acid sequences present in acchor-alpha-neurotoxin complexes. this method permit ... | 1986 | 3462717 |
| analysis of ligand binding to the synthetic dodecapeptide 185-196 of the acetylcholine receptor alpha subunit. | a synthetic dodecapeptide corresponding to residues 185-196 of the torpedo acetylcholine receptor alpha subunit, which contains the adjacent cysteine residues at positions 192 and 193, was recently shown by us to contain the essential elements for alpha-bungarotoxin binding. in the present study, we have used sepharose-linked peptides for quantitative analysis of the cholinergic binding properties of this and other synthetic peptides. sepharose-linked peptides corresponding to residues 1-20, 126 ... | 1986 | 3466185 |
| positive response to edrophonium in patients with neurotoxic envenoming by cobras (naja naja philippinensis). a placebo-controlled study. | to study the ability of anticholinesterase drugs to reverse the potentially fatal paralytic effects of cobra venom, we conducted a placebo-controlled, double-blind crossover trial of intravenous edrophonium (tensilon) in 10 adults with neurotoxic envenoming caused by bites of the philippine cobra (naja naja philippinensis). there was significantly more improvement in ptosis and endurance of upward gaze after edrophonium than after placebo. five minutes after injection, the mean difference (+/- s ... | 1986 | 3537783 |
| the action of various venoms on escherichia coli. | the antibacterial activity of honeybee venom (apis mellifera), three snake venoms (naja naja sputatrix, vipera russellii and crotalus adamanteus) and the polypeptide melittin was investigated against escherichia coli. minimum inhibitory concentration values, cell lysis and alterations in cell permeability were determined and action against e. coli was in the order: a. mellifera venom greater than melittin greater than n. naja sputatrix venom much greater than v. russellii venom greater than c. a ... | 1986 | 3542922 |
| effects of naja haje (egyptian cobra), naja naja (hooded cobra), naja nigricollis (spitting cobra) and naja mossambica mossambica (mozambique spitting cobra) venoms on the isolated guinea-pig tracheal muscle. | venoms from n. haje, n. naja, n. nigricollis and n. mossambica were tested on the isolated guinea-pig trachea. the four venoms (1-30 micrograms/ml) contracted the tracheal smooth muscle after a delay of 40-60 sec. a second challenge with the venoms caused either no or a much reduced contraction or a relaxant effect. the contraction could be prevented by pretreatment with antihistaminics, but not by atropine, methysergide or indomethacin, indicating that it is due to histamine release by the veno ... | 1986 | 3564065 |
| amino acid sequence of a less-cytotoxic basic polypeptide (lcbp) isolated from the venom of the indian cobra (naja naja). | a less-cytotoxic polypeptide, designated as lcbp, was isolated from the venom of naja naja by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of lcbp were both one order of magnitude lower than that of cytotoxins and that of toxin a, respectively. lcbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages, and the amino acid sequence is the sam ... | 1987 | 3566773 |
| characterization of the anticoagulants from taiwan cobra (naja naja atra) snake venom. | taiwan cobra (naja naja atra) snake venom was separated into 19 fractions by means of cm-sephadex c-50 column chromatography. anticoagulant fractions v-vii were refractionated by gel filtration on sephadex g-50 and the purified component possessed phospholipase a2 activity and an inhibitory effect on collagen-induced platelet aggregation. the anticoagulant action could be antagonized by phospholipid or platelet factor 3. anticoagulant fraction xvii was also further refractionated by gel filtrati ... | 1987 | 3576637 |
| different susceptibilities of platelet phospholipids to various phospholipases and modifications induced by thrombin. possible evidence of rearrangement of lipid domains. | on the membrane surface of the human platelet, phosphatidylcholine (pc) and phosphatidylethanolamine (pe) were hydrolyzed to different extents by the snake venom phospholipases a2 of varying pi values. the susceptibility of platelet phospholipids to basic phospholipase a2 of naja nigricollis (pi 10.6) has been reported (wang et al. (1986) biochim. biophys. acta 856, 244-258). the susceptibilities of platelet phospholipids to acidic phospholipase a2 of naja naja atra (pi 5.2) and to neutral phosp ... | 1987 | 3580366 |
| a new ribonuclease from cobra venom (naja naja) showing specificity towards cytidylic acid. | a ribonuclease was isolated and purified to homogeneity from cobra venom. the enzyme was found to be homogeneous on sds and non-sds polyacrylamide gel electrophoreses, and high performance liquid chromatography. the purified enzyme hydrolysed poly(rc), but not poly(ra), poly(ru), poly(rg), poly(ri), or poly(ri).poly(rc). the presence of magnesium was found to be an essential requirement for the nucleolytic activity of this enzyme. | 1987 | 3593367 |
| amino acid sequence of a cytotoxin-like basic protein with low cytotoxic activity from the venom of the thailand cobra naja naja siamensis. | a cytotoxin-like basic protein (clbp) was isolated from the venom of the thailand cobra (naja naja siamensis). the cytotoxicity of clbp toward fl cells was one order of magnitude lower than those of cytotoxins. the amino acid sequence was determined by a combination of conventional methods. the total number of amino acid residues was 62, giving a molecular mass of 6977 da. the sequence at residues 25-30 in the clbp molecule was found to be significantly different from those of cytotoxins. this r ... | 1987 | 3595859 |
| monoclonal antibody immunoaffinity chromatography of the nerve growth factor from snake venoms. | 1. pure monoclonal antibodies to vipera lebetina venom nerve growth factor have been isolated by affinity chromatography using cnbr-agarose bound antigen. 2. nerve growth factors from ten snake venoms (vipera lebetina, vipera russellii, vipera berus berus, vipera ursini, echis carinatus, agkistrodon halys, bungarus caeruleus, naja naja oxiana, naja naja, naja naja atra) were purified using monoclonal antibodies against ngf linked to brcn-activated agarose. | 2013 | 3621902 |