| basic phospholipase of naja nigricollis venom. | it is confirmed that n. nigricollis venom contains several phospholipases one of these is a basic phospholipase a. this enzyme is toxic for mice when injected intravenously. in vitro it reacts on egg yolk lecithin producing lysolecithin and prevents the phenomenon of blood clotting. an immunological identity has been established between this basic phospholipase and two acidic phospholipases present in the same venom. | 1975 | 151 |
| hypothermic effect in rats of naja nigricollis venom: role of acetylcholine. | | 1977 | 14425 |
| histopathological changes in fowls bitten by the spitting snake naja nigricollis. | | 1978 | 104494 |
| the effect of a cardiotoxic component of the venom of the indian cobra (naja nigricollis) on the subcellular structure and function of heart muscle. | | 1976 | 133248 |
| [action of calcium chloride in the cardiotoxicity in the rat of purified gamma toxin isolated from naja nigricollis venom]. | | 1975 | 806374 |
| [cardiotoxicity in rats of purified gamma toxin isolated from venom of naja nigricollis and of toxins extracted from scorpion venom]. | in vivo, atropine or tetrodotoxin prevent arrhytmias which are due to acetylcholine released by the scorpion's venom. on the contrary, atropine is ineffective against cardiotoxicity of the purified gamma toxin and tetrodotoxin aggravates its effects. these findings allow us to postulate the mechanism of action which differs in these two toxin groups. | 1975 | 811392 |
| cardiotoxin-like action of a basic phospholipase a isolated from naja nigricollis venom. | | 1977 | 882997 |
| [biological and immunological researches on snake venom. v. application of the immunochemical technics to the titration of specific antibodies to the alpha toxin of naja nigricollis venom (author's transl)]. | in order to establish a simple method to titrate antitoxin antibodies in the antivenom sera, we suggest a new immunochemical technic. to a constant dose of a pure toxin extracted from a snake venom, increasing volumes of specific immune serum are added so as an excess of toxin remains free. this residual toxin is titrated by electroimmunodiffusion technic according to laurell or by radial immunodiffusion method of mancini. the experimental results in vitro are compared to those obtained in vivo. ... | 1977 | 900896 |
| necrosis, haemorrhage and complement depletion following bites by the spitting cobra (naja nigricollis). | the spitting cobra, naja nigricollis, is widely and densely distributed in africa. fourteen patients with proven n. nigricollis bites, who were seen in the savanna region of nigeria, did not exhibit the neurological signs, such as cranial nerve lesions and respiratory paralysis, expected following elapid poisoning. all had local swelling, in eight cases involving the entire limb, and ten developed local tissue necrosis. spontaneous haemorrhage was detected in three cases and was the probable cau ... | 1976 | 943796 |
| snake venom ophthalmia and blindness caused by the spitting cobra (naja nigricollis) in nigeria. | venom entered the eyes of 9 patients spat at by the spitting cobra, naja nigricollis. in 5 the only effect was a simple conjunctivitis but 4 had corneal ulceration, 1 developed anterior uveitis indicating absorption of venom in the anterior chamber, and 2 were permanently blinded. treatment of this rare emergency is discussed: immediate irrigation of the eye with water, careful examination for corneal abrasion, and prevention of secondary infection are recommended. the value of local specific an ... | 1976 | 1084700 |
| the effect of several viper venoms on prothrombin padua. | the effect of four viper venoms (oxyuranus scutellatus, notechis scutatus scutatus, echis carinatus, naja nigricollis) on prothrombin padua has been studied. using oxyuranus scutellatus venom and notechis scutatus scutatus venom, prothrombin activity resulted to be moderately decreased similarly to what observed with other one-stage and two-stage methods. on the contrary, using echis carinatus venom a normal level was obtained. no clotting was observed using the naja nigricollis venom, regardles ... | 1975 | 1174715 |
| electron microscopy of alpha 2-macroglobulin with a thiol ester bound ligand. | in order to covalently bind the hydrolyzed thiol ester groups of the human alpha 2-macroglobulin (alpha 2m) transformed by methylamine, the phospholipase a2 (pla2), a small enzyme (m(r) = 13,000) from naja nigricollis snake venom was activated by succinimidyl 4-(maleimidomethyl)cyclohexane-1-carboxylate (smcc). average images determined from electron micrographs of the methylamine-transformed alpha 2m, with and without activated pla2, were determined by image processing and compared. a localizat ... | 1992 | 1282356 |
| inhibition of sendai virus by various snake venom. | viperid, elapid and crotalid snake venoms were screened in vitro for antiviral activity against sendai virus. the hemolysis of 10(8) human erythrocytes in 1 ml, caused by 70 hau of sendai virus, was abolished when the virions were pretreated with 10 ug of the viperid venom of echis coloratus, and was considerably diminished when pretreated with 10 ug of the venom of echis carinatus sochureki, the cobra venoms of naja atra and naja nigricollis nigricollis. these venoms did not affect the erythroc ... | 1992 | 1328790 |
| short term effects of animal venoms on the mitotic index of the duodenal mucosa of albino rats. | short term administration of the venoms of the snakes naja haje, naja nigricollis, and cerastes vipera and of the scorpion leiurus quinquestriatus on the mitotic index of the duodenal mucosal cells of the white rat, rattus rattus, has been studied. all the venoms increased the number of dividing cells of the duodenal mucosa significantly. naja haje crude venom was fractionated into three fractions. fraction i had no effect on the mitotic index whereas fractions ii and iii increased it significan ... | 1992 | 1344905 |
| effects of snake venom phospholipase a2 toxins (beta-bungarotoxin, notexin) and enzymes (naja naja atra, naja nigricollis) on aminophospholipid asymmetry in rat cerebrocortical synaptosomes. | the effects of snake venom phospholipase a2 (pla2) toxins (beta-bungarotoxin, notexin) and pla2 enzymes (naja nigricollis, naja naja atra) on aminophospholipid asymmetry in rat cerebrocortical synaptic plasma membranes (spm) were examined. incubation of intact synaptosomes with 2 mm 2,4,6-trinitrobenzene sulfonic acid (tnbs) for 40 min, under non-penetrating conditions, followed by spm isolation, allowed us to calculate the percentage of phosphatidylethanolamine (pe) and phosphatidylserine (ps) ... | 1992 | 1417932 |
| a national hospital-based survey of snakes responsible for bites in thailand. | snakes which had been killed and brought to hospital with the patients they had bitten were collected in 80 district and provincial hospitals throughout 67 provinces in thailand in order to establish the geographical distribution and relative medical importance of the venomous species. of the 1631 snakes collected, 1145 were venomous: malayan pit vipers (calloselasma rhodostoma), green pit vipers (trimeresurus albolabris) and russell's vipers (daboia russelii) were the most numerous, while t. al ... | 1992 | 1566285 |
| comparative effects of phospholipase a2 neurotoxins and enzymes on membrane potential and na+/k+ atpase activity in rat brain synaptosomes. | beta-bungarotoxin (beta-butx) and notexin are phospholipase a2 (pla2) neurotoxins which cause an irreversible blockade of neurotransmitter release through specific and potent effects at the presynaptic nerve terminal; however, their mechanism of action is uncertain. we examined the effects of beta-butx and notexin on na+/k+ atpase activity using sprague-dawley rat brain synaptosomes in order to determine if alterations in activity might modulate neurotoxin-induced depolarization. treatment of sy ... | 1991 | 1648801 |
| a monoclonal antibody recognizing a conserved epitope in a group of phospholipases a2. | notexin and nigexine are monomeric phospholipases a2(pla2s) from the venoms of notechis scutatus scutatus and naja nigricollis, respectively. polyclonal antibodies raised in mice against these antigenic proteins displayed non-reciprocal cross-reactivity; anti-notexin antibodies recognized notexin but not nigexine, whereas anti-nigexine antibodies recognized both antigens. polyclonal antibodies raised by successive immunization with nigexine and notexin contained cross-reacting antibodies with af ... | 1990 | 1690350 |
| isolation and characterization of a cytotoxin p4 from the venom of naja nigricollis nigricollis preferentially active on tumor cells. | cytotoxin p4 was isolated from the venom of naja nigricollis nigricollis in three steps and contained 55% of the crude cytotoxic activity. it had a molecular weight of 8 kd, was stable over a ph range of 1-11 and in boiling water for at least 15 min. it had no measurable enzymatic activities, but was destroyed by proteases. concentrations of 0.8, 1, 1.2, 25. 20 and 45 ug/ml, were needed to destroy murine melanoma b16 and wehi 3b leukemia, rat chondrosarcoma, mouse erythrocytes and spleen cells, ... | 1991 | 1772420 |
| neuromuscular effects of nigexine, a basic phospholipase a2 from naja nigricollis venom. | nigexine is a basic phospholipase a2 from the venom of the spitting cobra naja nigricollis. in addition to its anticoagulant and cytolytic properties, nigexine also affects neuromuscular transmission in vitro. on chick biventer cervicis preparations, 1.5 microm nigexine caused a slowly developing block of responses to nerve stimulation, and a progressive loss of postjunctional sensitivity. nigexine was at least 10 times less potent than notexin. on frog cutaneous pectoris preparations, nigexine ... | 1991 | 2048150 |
| dimeric character of a basic phospholipase a2 from cobra venom: experimental and modelling study. | when it is gel filtered on sephadex in the absence of calcium ions, basic phospholipase a2 from naja nigricollis venom elutes as a dimer. in order to study the possibility of this dimerization from a structural point of view, three-dimensional models of both monomeric and dimeric n. nigricollis phospholipases a2 have been graphically built on the basis of homologies with the phospholipases a2 from pancreatic bovine and crotalus atrox venom. the building of a dimeric model is made possible by the ... | 1990 | 2075192 |
| phospholipid hydrolysis and loss of membrane integrity following treatment of rat brain synaptosomes with beta-bungarotoxin, notexin, and naja naja atra and naja nigricollis phospholipase a2. | the effects of the phospholipase a2 (pla2) toxins, beta-bungarotoxin and notexin, and the pla2 enzymes from naja naja atra and naja nigricollis snake venoms on the plasma membrane integrity of synaptosomes were examined. synaptosomes were isolated from rat brain cerebral cortex, corpus striatum and hippocampus. osmotic activity, lactate dehydrogenase leakage, and leakage of 2-deoxy-d-(1-3h)-glucose-6-phosphate were monitored (37 degrees c, 10-120 min) following incubation with 0.5, 5 and 50 nm c ... | 1990 | 2080518 |
| rapid activation of the non-toxic basic isoform of phospholipase a2 from naja mossambica mossambica (spitting cobra) by long-chain fatty acylation. | purified phospholipase a2 from naja naja (common indian cobra) venom, a basic non-toxic isoform and a toxic isoform from naja mossambica mossambica venom were treated with an equimolar amount of oleoyl imidazolide, a known activator of bee venom phospholipase a2. the ability of the first two enzymes to induce erythrocyte lysis was strongly activated while hydrolysis of dioctanoyl phosphatidyl choline was only weakly activated. the toxic enzyme showed little change in either assay. the susceptibl ... | 1990 | 2080519 |
| inhibition of phosphorylation of rat synaptosomal proteins by snake venom phospholipase a2 neurotoxins (beta-bungarotoxin, notexin) and enzymes (naja naja atra, naja nigricollis). | some snake venom neurotoxins, such as beta-bungarotoxin (beta-butx) and notexin, which inhibit the release of neurotransmitter at both peripheral and central presynaptic terminals possess phospholipase a2 activity. in contrast, most snake venom phospholipase a2 enzymes such as those isolated from naja naja atra and naja nigricollis are structurally homologous to these neutrotoxins but do not have any specific or potent presynaptic action although they have higher enzymatic activities than the ne ... | 1990 | 2089738 |
| inhibitory effect of edta.ca2+ on the hydrolysis of synaptosomal phospholipids by phospholipase a2 toxins and enzymes. | phospholipases a2 (pla2) are ca2(+)-dependent enzymes that are inhibited by edta; this inhibition would be expected to be reversed by restoring the ca2+ concentration. by examining the hydrolysis of synaptosomal phospholipids by pla2 enzymes, naja naja atra and naja nigricollis, and by toxins with pla2 activity, beta-bungarotoxin (beta-butx) and notexin, we demonstrated a novel inhibitory action of edta manifested in the presence of excess ca2+. we postulate the formation of an edta.ca2+ complex ... | 1990 | 2123106 |
| 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 |
| on the mode of action of basic phospholipase a2 from naja nigricollis venom. | a study has been made of the cytotoxic activity of basic phospholipase a2 of venom from naja nigricollis on different types of cells and of the participation of esterase activity in this cytotoxic activity. it was previously shown that the cytotoxicity observed is not due to a contaminant, since the cytotoxic action vanished after immunoprecipitation of basic phospholipase a2 by specific monoclonal antibodies. all eukaryotic cells tested were sensitive to the cytotoxic action of basic phospholip ... | 1990 | 2386800 |
| a study of the pathogenesis of local skin necrosis induced by naja nigricollis (spitting cobra) venom using simple histological staining techniques. | the course of degeneration and regeneration of mouse skin following intradermal injection of spitting cobra (n. nigricollis) venom was investigated using simple histological staining techniques. early changes observed were vascular congestion, oedema and degeneration of the skeletal muscle cell layer (panniculus carnosus) in the area local to the injection site. fuchsin staining of degenerative muscle cells in haematoxylin-basic fuchsin-picric acid (hbfp) stained sections appeared long before an ... | 1987 | 2442855 |
| role of cationic residues in cytolytic activity: modification of lysine residues in the cardiotoxin from naja nigricollis venom and correlation between cytolytic and antiplatelet activity. | cardiotoxins and postsynaptic neurotoxins from snake venoms have similar primary, secondary, and tertiary structures. cardiotoxins, however, in contrast to neurotoxins, exhibit general cytotoxicity. comparison of the distribution of hydrophobic and charged amino acid residues in the three-dimensional structures of lytic cardiotoxins and nonlytic neurotoxins indicates the presence of a cationic site associated with a hydrophobic surface in cardiotoxins, but not in neurotoxins. a cationic site fla ... | 1989 | 2513886 |
| is direct cardiotoxicity the primary cause of death following i.v. injection of the basic phospholipase a2 from naja nigricollis venom? | the primary cause of death following i.v. injection of the basic phospholipase a2 (pla2) from naja nigricollis venom has been attributed to its direct cardiotoxicity. in view of our recent findings that cardiac failure caused by the basic pla2 from naja m. mossambica is primarily due to hyperkalemia resulting from cellular damage and possibly also from hemolysis, the cause of death due to the basic pla2 from naja nigricollis was re-investigated. in the anesthetized mice and rats, the pla2 (0.3 m ... | 1989 | 2520358 |
| 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 |
| nigexine, a phospholipase a2 from cobra venom with cytotoxic properties not related to esterase activity. purification, amino acid sequence, and biological properties. | the venoms of the naja species are known to be cytotoxic. this toxicity has been attributed to the presence of small nonenzymatic polypeptides of 60 amino acid residues, designated as cardiotoxins or cytotoxins. we investigated the cytotoxic potency of naja nigricollis venom fractions and isolated another type of cytotoxic component which is even more potent than cardiotoxins. this cytotoxic compound, which was designated as nigexine, was purified to homogeneity and its amino acid sequence was d ... | 1989 | 2753914 |
| the inhibition of clotting complexes of the extrinsic coagulation cascade by the phospholipase a2 isoenzymes from naja nigricollis venom. | phospholipase a2 (pla2) isoenzymes from naja nigricollis venom exhibit anticoagulant activity with varying potencies. to determine which complexes in the extrinsic coagulation cascade are inhibited by these pla2 enzymes, we examined their effects on the coagulation of bovine plasma initiated by the addition of thromboplastin, russell's viper venom (rvv) or thrombin. the weakly anticoagulant pla2 enzymes, cm-i and cm-ii, prolonged clotting initiated by thromboplastin, but not that initiated by rv ... | 1989 | 2814939 |
| the role of enzyme activity and charge properties on the presynaptic neurotoxicity and the contracture-inducing activity of snake venom phospholipases a2. | two toxic phospholipases a2, caudoxin from bitis caudalis venom and the basic phospholipase a2 from naja nigricollis venom, were selected for a study of the contribution of enzyme activity and charge properties to the presynaptic neurotoxicity and the contracture-inducing activity of the enzyme. reducing catalytic activity by lowering the incubation temperature or by substitution of sr2+ for ca2+ in the bathing medium causes a significant prolongation of the time to neuromuscular block by caudox ... | 1986 | 3087027 |
| cardiotoxicity of naja nigricollis phospholipase a2 is not due to alterations in prostaglandin synthesis. | the basic phospholipase a2 from naja nigricollis snake venom is cardiotoxic, causing decreased contractility and arrhythmias at concentrations which induce low levels of phospholipid hydrolysis. cardiac tissue has a high content of arachidonic acid at the sn-2 position of the major membrane phospholipids, thus increased prostaglandin synthesis might contribute to the cardiotoxic effects of n. nigricollis phospholipase a2. intracellular action potentials and cardiac contractility were monitored i ... | 1986 | 3105122 |
| 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 |
| 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 |
| reversal of snake neurotoxin binding to mammalian acetylcholine receptor by specific antiserum. | snake curaremimetic toxins are known to bind to the nicotinic acetylcholine receptor (acchor) [changeux et al. (1970) proc. natl acad. sci. usa, 67, 1241-1247], thus blocking neuromuscular transmission, and producing respiratory failure in mammals. in the present paper we show that the toxic effects of naja nigricollis toxin alpha to mammals can be efficiently reversed by toxin-alpha-specific antibodies. in vivo we observed that return to normal breathing in toxin-alpha-intoxicated and ventilate ... | 1988 | 3345745 |
| 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 |
| 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 |
| ocular effects of the venom from the spitting cobra (naja nigricollis). | n. nigricollis venom caused transient corneal oedema, extensive chemosis and pupillary dilation when applied topically to the corneas of albino and pigmented rabbits. after 1 month, permanent corneal scarring, neovascularization and deepithelialization was noted in albino eyes, whereas minimal scarring or deepithelialization occurred in pigmented eyes. in contrast, mydriasis and cycloplegia occurred initially in the pigmented eye, with the pupil remaining fixed and dilated for more than 7 days. ... | 1986 | 3723645 |
| differences in pharmacological actions between beta-bungarotoxin and other neurotoxic phospholipases a2 purified from snake venoms. | five highly toxic phospholipases a2 (plas) (beta-bungarotoxin, caudoxin, mojave toxin, notexin and a basic pla from naja nigricollis venom) were compared for their pharmacological actions. in the chick biventer cervicis nerve-muscle preparation, all pla toxins except beta-bungarotoxin (beta-butx) inhibited the postsynaptic acetylcholine response and induced contracture of the muscle at a high concentration. indirect hemolytic activity was found in all pla toxins and some of the toxins (naja nigr ... | 1986 | 3774915 |
| effects of modification of tyrosines 3 and 62 (63) on enzymatic and toxicological properties of phospholipases a2 from naja nigricollis and naja naja atra snake venoms. | previously we selectively modified his (48), arg, lys, asp, glu and trp residues in the basic phospholipase a2 from naja nigricollis and the acidic phospholipase a2 from n. n. atra snake venoms. evidence was obtained for the existence of separate but perhaps overlapping sites responsible, respectively, for their enzymatic and pharmacological properties. we have now modified one or two (tyr 3, tyr 62 [63], tyr 3 + 62 [63]) out of the nine tyrosine residues in these enzymes using p-nitrobenzenesul ... | 1986 | 3775785 |
| effect of alkylation of tryptophan residues on the enzymatic and pharmacological properties of snake venom phospholipase a2. | snake venom phospholipases a2 show a remarkable degree of amino acid sequence homology yet differ markedly in enzymatic and pharmacological activities. the basic phospholipase a2 from naja nigricollis venom has much greater lethal potency, cardiotoxicity, hemolytic and anticoagulant activity than the acidic or neutral enzymes from naja naja atra or hemachatus haemachatus venoms, respectively, even though it has lower enzymatic activity than the latter two enzymes. previous studies in which we se ... | 1985 | 3924381 |
| estimation of the phospholipid distribution in the human platelet plasma membrane based on the effect of phospholipase a2 from naja nigricollis. | human platelets in three physiological states were prepared. these states were the gel-filtered, the thrombin-induced shape-changed, and the thrombin-activated platelets. the phospholipid distributions in these three types of membrane were probed by using the basic phospholipase a2 of naja nigricollis. this enzyme could penetrate through these membranes to hydrolyze all of their accessible phospholipids and to cause cell lysis. the hydrolytic time-courses displayed three phases. the state of pla ... | 1986 | 3955041 |
| the relationship between high-affinity noncatalytic binding of snake venom phospholipases a2 to brain synaptic plasma membranes and their central lethal potencies. | the basic phospholipase a2 from naja nigricollis (african spitting cobra) snake venom is enzymatically less active but more toxic than the acidic phospholipase a2 from naja naja atra (taiwan cobra) snake venom, following injection into the right lateral ventricle of the brain of rats. when radiolabeled with 125i, these phospholipases a2 retained enzymatic activities and lethal potencies. both enzymes bound with high affinity and specificity to brain synaptic plasma membrane preparations in vitro ... | 1986 | 3964691 |
| [corneal necrosis caused by spitting cobra venom fraction]. | | 1985 | 4007742 |
| experimental studies on the spitting cobra ophthalmia (naja nigricollis). | experimental studies were conducted to investigate the clinical and morphological effects of various doses of naja nigricollis venom (0.1-5.0 mg) on the eyes of rabbits. our findings suggest that in the early stage of the ophthalmia caused by the spitting cobra, specific fractions of the venom are responsible for the nitrogen mustardlike effect. however, the further course seems to be determined by liberated inflammation mediators like prostaglandins and leukotrienes. | 1985 | 4054642 |
| effects of naja nigricollis venom on blood and tissue histamine. | | 1971 | 4102694 |
| immunodiagnosis of snake bite. | management of a patient with snake bite is influenced by the nature of the offending snake. species diagnosis based on the patient's history and physical signs is often unreliable and the possibility of making a species diagnosis by immunological means has therefore been investigated. wound aspirates, blister fluids, sera, and urine samples from patients with snake bite were examined for the presence of species-specific venoms using immunodiffusion. a positive species diagnosis was made in 40 ou ... | 1974 | 4216390 |
| regulation of acetylcholine receptors in relation to acetylcholinesterase in neuroblastoma cells. | purified alpha-toxin from naja nigricollis snake venom labeled by [(3)h]acetylation binds specifically to the acetylcholine receptors of mouse neuroblastoma cells. toxin binding was inhibited by inhibitors for nicotinic and muscarinic acetylcholine receptors. clones of neuroblastoma cells were selected for low acetylcholinesterase (ec 3.1.1.7) activity with antibodies against this enzyme. selection for an 80-fold decrease in acetylcholinesterase activity was not associated with any decrease in t ... | 1973 | 4517944 |
| [isolation of 1 anti-toxin antibodies from the venom of naja nigricollis with sepharose]. | | 1972 | 4624806 |
| [immunogenic power of the alpha toxin from naja nigricollis venom polymerized by formaldehyde]. | | 1972 | 4631978 |
| [curarizing action of alpha toxin of naja nigricollis]. | | 1966 | 4963915 |
| [pharmacologic action of pure naja nigricollis venom fractions and calcium liberation in striated muscles]. | | 1969 | 4979076 |
| [isolation of a toxic protein from naja nigricollis venom]. | | 1969 | 4980264 |
| [biochemical and immunological studies on snake venom. iv. action of formaldehyde on the alpha toxin of naja nigricollis venon]. | | 1971 | 5003739 |
| diabetogenic actions of naja nigricollis venom. i. effects on glucose tolerance, plasma insulin-like activity and blood potassium. | | 1972 | 5079723 |
| [comparative neuromuscular action of naja nigricollis venom and the neurotoxin (alpha-najatoxin) which is extracted from it]. | | 1971 | 5093189 |
| the effect of naja nigricollis venom on blood clotting. | | 1971 | 5576546 |
| incidence and mortality on snake bite in savanna nigeria. | snake bite is a major medical problem among farming communities in the benue and niger valley savanna region of nigeria. surveys in the more densely populated northern savanna areas such as malumfashi (incidence 48 per 100 000 population, mortality 5.1%) show that the spitting cobra, naja nigricollis, was the predominant species of medical importance. in the less cultivated benue valley area the annual snake-bite incidence was estimated to be 497 per 100 000 population, with a 12.2% mortality du ... | 1980 | 6107780 |
| proteolytic activities of cobra venoms based on inactivation of alpha 2-macroglobulin. | the venoms of various cobra species showed a wide range of abilities to cleave hide powder azure, with naja naja kaouthia and ophiophagus hannah venoms showing the lowest activities and naja nivea venom showing the greatest activity on this dye-linked substrate. the activities of the venoms on hide powder did not completely correlate with their ability to inactivate the alpha 2-macroglobulin of human serum. incubation of 4-5 micrograms of naja nigricollis venom per microliter of serum for 30 min ... | 1984 | 6197999 |
| acid and alkaline phosphomonoesterases in egyptian snake venoms. | non-specific acid and alkaline phosphomonoesterases could be demonstrated in two viperids (cerastes cerastes and cerastes vipers) and two elapids (naja haje and naja nigricollis). the latter could be a natural source for the production of these enzymes. the activities of both enzymes in elapids were greater than in viperids. n. nigricollis was the only to show acid phosphatase activity exceeding its alkaline one. the optimum ph values recorded for acid phosphatase was 4.0 and 4.9 and for alkalin ... | 1981 | 6264698 |
| basic phospholipase a2 from naja nigricollis snake venom: phospholipid hydrolysis and effects on electrical and contractile activity of the rat heart. | | 1982 | 6297123 |
| purification and properties of a fibrinogenase from the venom of naja nigricollis. | a fibrinogenolytic proteinase from the venom of naja nigricollis was purified by chromatography on bio-rex 70 and phenyl-sepharose. the purified enzyme, designated proteinase f1, was homogeneous by the criterion of sds-polyacrylamide gel electrophoresis, and consisted of a single chain with a molecular weight of 58,000. purified proteinase f1 had approximately 15-fold more proteinase activity than the crude venom, based on its ability to inactivate alpha 2-macroglobulin. the enzyme acted on only ... | 1984 | 6435687 |
| cardiotoxic effects of naja nigricollis venom phospholipase a2 are not due to phospholipid hydrolytic products. | n. nigricollis phospholipase a2 (200 micrograms) has marked cardiotoxic actions on the perfused rat heart including the induction of arrhythmias, increases in ventricular thresholds, conduction and resting tension, and decreases in contractile tension. in contrast, perfusion with lysophosphatidyl choline and oleic acid, in concentrations comparable to those estimated to be formed during n. nigricollis treatment, has little effect on cardiac function. the less toxic n. n. atra phospholipase a2 al ... | 1984 | 6472061 |
| [light, scanning and transmission electron microscopy study of a spitting cobra injury]. | | 1984 | 6479779 |
| effect of carboxylate group modification on enzymatic and cardiotoxic properties of snake venom phospholipases a2. | by treating naja nigricollis and naja naja atra phospholipase a2 with carbodiimide and semicarbazide, we obtained derivatives having varied numbers of modified carboxylate groups. when tested on artificial and natural substrates, derivatives of both enzymes with a modified carboxylate group at the active site (asp-49) retained little enzymatic activity (1/41 to 10%). however, the derivatives of n. nigricollis also lost most of their lethal potency (5% of native), while those of n. n. atra retain ... | 1984 | 6523504 |
| phospholipid hydrolysis in serum lipoproteins by a basic phospholipase a2 from naja nigricollis snake venom and an acidic phospholipase a2 from naja naja atra snake venom. | apparent km and vmax values for pc and pe hydrolysis were determined following exposure of hdl, ldl, and vldl to a basic phospholipase a2 from n. nigricollis snake venom and an acidic phospholipase a2 from n. nigricollis snake venom and an acidic phospholipase a2 from n. n. atra snake venom. both enzymes hydrolyzed the lipoprotein phospholipids approximately as fast as they hydrolyzed pure phospholipids in mixed micelles, however, the n. nigricollis enzyme, which has a much stronger anticoagulan ... | 1983 | 6623492 |
| dissociation of pharmacological and enzymatic activities of snake venom phospholipases a2 by modification of carboxylate groups. | the carboxylate groups in an acidic and in a basic phospholipase a2 (pla2) enzyme, purified, respectively, from naja naja atra and naja nigricollis snake venoms, were modified with carbodiimide and semicarbazide. the derivatives modified at ph 3.5 and ph 5.5 had less than 1% (n. nigricollis) or 2% (n. n. atra) residual enzymatic activity, whereas 12-16% enzymatic activity remained following modification at ph 5.5 in the presence of ca2+. in marked contrast, these derivatives retained variable, b ... | 1983 | 6651873 |
| comparative studies on egyptian elapid venoms. | the immunological properties of naja haje from western desert, naja haje of the nile delta, naja nigricollis from upper egypt and walternnesia aegyptia from sinai desert were compared using horse serum antivenin prepared from the delta naja haje venom. all elapid venoms showed very similar precipitin lines with immunodiffusion or immunoelectrophoresis on agar gel. results of cellulose-acetate electrophoresis showed either different concentration of certain similar protein components or the absen ... | 1980 | 6781151 |
| dissociation of enzymatic activity from lethality and pharmacological properties by carbamylation of lysines in naja nigricollis and naja naja atra snake venom phospholipases a2. | | 1981 | 6795762 |
| effect of methylation of histidine-48 on some enzymatic and pharmacological activities of snake venom phospholipases a2. | the effects on some pharmacological and enzymatic properties were determined following methylation of histidine at the enzymatic active site of the basic relatively toxic naja nigricollis and the acidic relatively non-toxic naja naja atra phospholipases a2. following methylation a very low residual enzymatic activity (0.4-1% of control) was accompanied by a parallel loss in intraventricular lethality, anticoagulant potency, direct hemolytic action and ability to block directly and indirectly evo ... | 1983 | 6834999 |
| observations on the bite of the mozambique spitting cobra (naja mossambica mossambica). | experience in the treatment of bites by the mozambique spitting cobra. naja mossambica mossambica peters, is described, and it is shown that the predominant effect of the venom is cytotoxic. the gross pathology of the bite is presented. a large percentage of the bites (94%) occurred inside human dwellings, and of these, 81% occurred while the victims were asleep. the efficacy of the saimr's polyvalent antivenom was tested, and the evidence suggests that its effectiveness is indirectly proportion ... | 1982 | 7058469 |
| comparative study of three basic polypeptides from snake venoms in relation to their effects on the cell membrane of normal and tumor cells. | basic polypeptides producing a variety of effects on animals and cells have been isolated from snake venoms. many possess common structural features and also produce similar pharmacological effects. this has led to doubt as to the specificity of each polypeptide. study of toxin gamma (cardiotoxin from naja nigricollis), cytotoxin p6 (from naja naja, preferentially cytotoxic to certain cells) and neurotoxin alpha (naja nigricollis) under identical conditions shows that they are separate entities ... | 1980 | 7214315 |
| effect of modification of one histidine residue on the enzymatic and pharmacological properties of a toxic phospholipase a2 from naja nigricollis snake venom and less toxic phospholipases a2 from hemachatus haemachatus and naja atra snake venoms. | | 1981 | 7222090 |
| effects of arginine modification of naja nigricollis and naja naja atra snake venom phospholipases a2 on enzymatic activity, lethality and anticoagulant action. | | 1981 | 7302958 |
| phospholipase a2 activity and substrate specificity of snake venom presynaptic toxins. | beta-neurotoxins from certain snake venoms are highly specific toxins acting at the presynaptic side of the neuromuscular junction. in this study biochemical aspects of this high specificity have been investigated. when toxins (notexin and naja nigricollis basic phospholipase) act on a mixture of subcellular fractions obtained from brain cortex (synaptosomes, myelin, and mitochondria), the synaptosomal fraction is preferentially attacked and shows the highest release of membrane protein. as seen ... | 1980 | 7370229 |
| chemical modification of the histidine residue in basic phospholipase a2 from the venom of naja nigricollis. | phospholipase a2 from naja nigricollis venom was separated into three fractions by chromatography on a column of cm-sephadex c-25. the pi values of fractions cms-5, cms-6 and cms-9 were determined to be 7.6, 8.3 and 10.6, respectively. fraction cms-9 was further purified on a deae-sephacel column and the homogeneity was verified. the specific activity of cms-9 was found to be 1300 units per mg and lethal toxicity 0.3 mg per kg mouse. the most basic and toxic fraction, cms-9, was subjected to che ... | 1980 | 7407195 |
| malumfashi endemic diseases research project, xiii. epidemiology of human encounters with the spitting cobra, naja nigricollis, in the malumfashi area of northern nigeria. | | 1980 | 7469568 |
| exposure of phosphatidylcholine and phosphatidylinositol in plasma membranes from rat brain synaptosomes treated with phospholipase a2 toxins (beta-bungarotoxin, notexin) and enzymes (naja nigricollis, naja naja atra). | phospholipase a2 (pla2) toxins act presynaptically to block acetylcholine release and are much more potent and specific in their actions than pla2 enzymes even though they have lower enzymatic activity. since their mechanism of action is not completely understood, it was of interest to examine the toxins' effects on phospholipid asymmetry as changes in asymmetry are associated with changes in membrane functioning. rat brain synaptosomes were treated with the pla2 toxins beta-bungarotoxin (beta-b ... | 1994 | 7940575 |
| [snake bite by a poisonous snake. report of an unusual case]. | we report on a 31-year-old white woman, who was bitten in her right calf by a "spitting cobra" (neia nigricollis) during a safari in tansania. minor initial systemic symptoms such as nausea and vomiting were followed by severe oedematous swelling of the extremity after 2-3 h and demarcation of a 2.75 x 2.75 in. area of necrotic skin. the patient returned to her home country, where 8 days after the snake-bite necrosectomy was performed. antibiotics, anti-inflammatory agents and local therapy with ... | 1994 | 8050904 |
| the ocular effects of spitting cobras: i. the ringhals cobra (hemachatus haemachatus) venom-induced corneal opacification syndrome. | venom from the ringhals cobra (h. haemachatus) caused extensive chemosis, prolonged corneal edema and marked miosis when applied locally to the eyes of two strains of rabbits: buskat (albino) and chinchilla (pigmented). in the pigmented rabbits, the corneal edema progressed to complete corneal opacification with corneal and conjunctival neovascularization that remained unchanged until the end of the experiment (70 d). in the albino rabbits the corneal cloudiness and conjunctivitis cleared within ... | 1993 | 8433414 |
| the ocular effects of spitting cobras: ii. evidence that cardiotoxins are responsible for the corneal opacification syndrome. | fractionation of h. haemachatus, n. nigricollis, n. nivea and n. melanoleuca venoms using amberlite cg-50 and (nh4)hco3 elution gradient chromatography yielded 11-13 fractions for each venom. one fraction, f x, from h. haemachatus, two fractions, f x and f xi, from n. nigricollis and one fraction, f viii, from n. melanoleuca venoms possessed the whole of ocular activity of the venoms. the fractions were the only venom fractions that caused cardiac depressant activity; their effect was reversed b ... | 1993 | 8433415 |
| encapsulation of the cobra cytotoxin p4 in liposomes. | cytotoxin p4 isolated from the venom of the cobra naja nigricollis nigricollis was encapsulated in liposomes by the reverse-phase evaporation method using phosphatidylcholine, cholesterol and phosphatidylethanolamine at molar ratios of 3:1:1. cytotoxicity examination on murine melanoma b16f10 revealed that the activity of the entrapped cytotoxin did not change significantly and remained stable for at least 1 year at 4 degrees c without any significant leak from the liposomes (< 1%). moreover, th ... | 1993 | 8439402 |
| molecular cloning of a cardiotoxin structural gene from malayan spitting cobra (naja naja sputatrix). | the structural gene and cdna encoding cardiotoxin in naja naja sputatrix have been cloned and characterized with a view to study the gene protein relationships and also to produce pure protein in large amounts. using the polymerase chain reaction on the total rna isolated from the venom glands, the structural gene (180 bp) has been synthesized and expressed in escherichia coli to produce a fusion protein with beta-galactosidase. immunoblotting using polyclonal antibodies raised against the total ... | 1993 | 8446963 |
| the role of enzymatic activity in inhibition of the extrinsic tenase complex by phospholipase a2 isoenzymes from naja nigricollis venom. | three phospholipase a2 isoenzymes from naja nigricollis venom inhibit the extrinsic tenase complex. we examined the role of their enzymatic activity in this inhibition by studying the effects of native and his-modified enzymes. only cm-iv of the his-modified, catalytically inactive proteins showed significant inhibition of the activity of the complex. this indicates that strongly anticoagulant cm-iv inhibits the complex by both enzymatic and nonenzymatic mechanisms, whereas the weakly anticoagul ... | 1995 | 8866616 |
| a three-compartment open pharmacokinetic model can explain variable toxicities of cobra venoms and their alpha toxins. | the pharmacokinetic profiles of labelled naja melanoleuca, naja nivea, naja nigricollis and naja haje venoms and their alpha neurotoxins were determined following rapid i.v. injection into rabbits. the data obtained fitted a triexponential equation characteristic of a three-compartment open pharmacokinetic model comprising a central compartment 'blood', a rapidly equilibrating 'shallow' tissue compartment and a slowly equilibrating 'deep' tissue compartment. the distribution half-lives for the s ... | 1996 | 8896193 |
| cloning and characterization of cdnas encoding three isoforms of phospholipase a2 in malayan spitting cobra (naja naja sputatrix) venom. | cdnas encoding three phospholipase a2 (pla2) isoforms in naja naja sputatrix were cloned and characterized. one of them encoded an acidic pla2 (apla) while the others encoded neutral pla2 (npla-1 and npla-2). the specific characteristics of apla and npla were attributed to mutations at nt139 and nt328 from g to c and g to a, respectively, resulting in amino acid substitutions from asp20 and 83 in apla to his20 and asn83 in npla. amino acid sequencing of purified protein also showed the presence ... | 1997 | 9028006 |
| activity of cytotoxin p4 from the venom of the cobra snake naja nigricollis on gram-positive bacteria and eukaryotic cell lines. | the cytotoxin p4 from the venom of the cobra snake naja nigricollis was examined for activity against aerobic gram-positive and gram-negative bacteria, yeasts, fungi and eucaryotic cell lines by determination of minimal inhibitory concentrations (mic) and ic50 values, respectively. cytotoxin p4 exhibits antimicrobial activity against bacillus subtilis, micrococcus flavus and sarcina lutea. targets in gram-negative bacteria and fungi apparently were not reached. toxicity against eucaryotic cells ... | 1997 | 9205785 |
| glycosaminoglycans bind to homologous cardiotoxins with different specificity. | we have reported that some cardiotoxins (ctxs), homologous basic polypeptides of cobra venom, bind strongly to heparin. herein we show that ctxs from spitting cobra venom bind avidly to chondroitin-6-sulfate (cs6) and dermatan sulfate (ds), the glycosaminoglycans (gags) abounding in the cornea and elsewhere. we compared the binding strength of tgamma, a major component of spitting cobra, naja nigricollis, venom with that of ctx a3, a major component of naja atra venom to various gags including c ... | 1998 | 9521773 |
| six isoforms of cardiotoxin in malayan spitting cobra (naja naja sputatrix) venom: cloning and characterization of cdnas. | cardiotoxins are the most abundant toxin components of cobra venom. although many cardiotoxins have been purified and characterized by amino acid sequencing and other pharmacological and biochemical studies, to date only five cardiotoxin cdnas from taiwan cobra (naja naja atra), three cdnas from chinese cobra (naja atra) and two more of uncertain origin (either chinese or taiwan cobra) have been reported. in this paper we show the existence of four isoforms of cardiotoxin by protein analysis and ... | 1998 | 9565688 |
| venomous snakebite in thailand. i: medically important snakes. | thailand has an abundance of venomous snakes. among the neurotoxic family elapidae, there are three species of the genus naja (cobras), three of the genus bungarus (kraits), and the king cobra of the genus ophiophagus. other elapidae snakes in thailand include sea snakes and asian coral snakes of the genus calliophis. they have potent venoms but rarely bite humans. tissue and hemotoxic snakes are represented by family viperidae, subfamilies viperinae and crotalinae. they remain an occupational h ... | 1998 | 9597848 |
| four new postsynaptic neurotoxins from naja naja sputatrix venom: cdna cloning, protein expression, and phylogenetic analysis. | cdnas encoding 4 short chain alpha-neurotoxins from malayan spitting cobra (naja naja sputatrix) venom were cloned and expressed in escherichia coli. the recombinant toxins possessed identical amino acid sequences to alpha-neurotoxins. this is the first report on cloning and expression of isoforms of neurotoxins from a species of spitting cobra. two of these isoforms were also identified in the crude venom by reverse phase-high performance liquid chromatography (rp-hplc), capillary electrophores ... | 1998 | 9839671 |
| changes in myosin heavy chain profile of mature regenerated muscle with endurance training in rat. | the objective of the present study was to examine the response of fast-twitch muscle to endurance training long after the muscle had regenerated from toxin injury. seventeen male wistar rats were randomly assigned to a sedentary (s, n = 10) or a trained group (t, n = 7). endurance training by treadmill running (5 days week(-1), 30 m min(-1), 7% grade, 2 h day(-1) for 5 weeks) was initiated 5 weeks after myofibre degeneration was induced in the right extensor digitorum longus muscle (edl) by two ... | 1999 | 10090330 |
| selective lysis of virus-infected cells by cobra snake cytotoxins: a sendai virus, human erythrocytes, and cytotoxin model. | by using a sendai virus-human erythrocyte model, this work found that virus-infected cells were 10-fold more susceptible to lysis in two of five examined cobra venoms. four cytotoxins were isolated from the venom of the cobra naja nigricollis that also showed 10-fold higher cytotoxicity toward virus-infected cells than to untreated cells. as selective destruction of virus-infected cells is of immense importance in clinical practice, this work demonstrates the potential of cobra cytotoxins to ser ... | 1999 | 10527842 |
| antibacterial properties of kwazulu natal snake venoms. | the objective was to ascertain whether local snake venoms have antibacterial properties. the venoms of the common night adder (causus rhombeatus), gaboon adder (bitis gabonica), puff adder (bitis arietans), black mamba (dendroaspis polylepis), eastern green mamba (dendroaspis augusticeps), forest cobra (naja melanoleuca), snouted cobra (naja annulifera) and mozambique spitting cobra (naja mossambica) were collected and, by gel diffusion, tested against the bacteria staphylococcus aureus, escheri ... | 2000 | 10775753 |
| pentastomes (pentastomida, armillifer armillatus wyman, 1848) in snakes from zambia. | twenty-three snakes, belonging to eight different species, were collected from rural areas of zambia and inspected for the presence of pentastomes. pentastomid parasites were found in four snakes: one african rock python (python sebae), one puff adder (bitis arietans) and two mozambique spitting cobras (naja mossambica) were infested with a small number of armillifer armillatus, respectively five, two and one adult parasites. as humans can be incidental/intermediate hosts for reptilian pentastom ... | 1999 | 10870563 |
| structure and phylogeny of the venom group i phospholipase a(2) gene. | phospholipases a(2) (pla(2)s) catalyzing the hydrolysis of phospholipids form a family of proteins with diverse physiological and pharmacological properties. while there have been several reports on the cloning of pla(2) cdnas, very few studies have been carried out on the pla(2) genes and, most importantly, no information has been available on the gene structure and function of group i venom pla(2). this study, on the pla(2) gene from a spitting cobra, besides being the very first report on any ... | 2000 | 10889214 |
| tetanus complicating snakebite in northern nigeria: clinical presentation and public health implications. | there is inequality in vaccination coverage, and adult farmers in tropical rural communities could have missed tetanus toxoid as campaigns target children. snakebite is not uncommon and partly because of lack of effective antivenom, management in inaccessible areas could be complicated with tetanus in unimmunized victims. | 2003 | 12505187 |