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phospholipase a2 as a probe of phospholipid distribution in erythrocyte membranes. factors influencing the apparent specificity of the reaction.the action of snake venom phospholipases a2 in intact human erythrocytes was investigated in detail. the basis phospholipase from agkistrodon halys blomhifii was found to induce both hydrolysis of membrane phospholipids and total cell hemolysis under certain experimental conditions. the hydrolytic action of the basic enzyme was found to consist of two sequential events: (a) hydrolysis of 70% of the total cell ph osphatidylcholine without any evident hemolysis; and (b) complete hydrolysis of the ...197554
beta-bungarotoxin, a pre-synaptic toxin with enzymatic activity.beta-bungarotoxin, a pre-synaptic neurotoxin isolated from the venom of the snake bungarus multicinctus, has been shown to modify release of neurotransmitter at the neuromuscular junction. in this communication, we demonstrate that beta-bungarotoxin is a potent phospholipase a2 (phosphatide 2-acyl hydrolase, ec 3.1.1.4), comparable in activity with purified phospholipase enzymes from naja naja and vipera russellii. the phospholipase activity of beta-bungarotoxin requires calcium and is stimulate ...19761749
studies on the annual reproductive cycle of the female cobra, naja naja. seasonal variation in plasma inorganic ions. 19762437
proton-nuclear-magnetic-resonance study of the conformation of neurotoxin ii from middle-asian cobra (naja naja oxiana) venom.a proton nuclear magnetic resonance (nmr) study at 100 and 300 mhz of neurotoxin ii from the venom of middle-asian cobra naja naja oxiana has been performed in 2h2o and h2o solutions. by means of chemical modification and double resonance all the aromatic residue resonances have been assigned. from the nmr titration curves, pk values of histidine 4 and histidine 31 residues have been determined. for one of the two neighbouring tryptophan residues ph dependence (in the 2-8-ph range) of the chemic ...197612972
chemical modification of the histidine residue in phospholipase a2 (naja naja naja). a case of half-site reactivity.reaction of phospholipase a2 (naja naja naja) with p-bromophenacyl bromidine leads to almost complete loss of enzymatic activity. the rate of inactivation is ph-dependent with pka equals 6.9 for the ionizing residue. p-bromophenacyl bromide modifies 0.5 mol of histidine/mol of enzyme as judged by amino acid analysis and incorporation studies with 14c-labeled reagent. the rate of inactivation is affected by various cations; a saturating concentration of ca2+ decreases the rate 5-fold, while mn2+ ...197714964
comparative cardiovascular and respiratory effects of bungarus fasciatus and naja naja siamensis venoms in dogs. 197826508
the 1h nuclear-magnetic-resonance spectra of neurotoxin i and cardiotoxin vii4 from naja mossambica mossambica.two toxins from the venom of naja mossambica mossambica, neurotoxin i and cardiotoxin vii4, were investigated in aqueous solution by high-resolution 1h nuclear magnetic resonance (nmr) techniques at 360 mhz. the spectral characterization of the proteins included determination of the number of slowly exchanging amide protons which can be observed in 2h2o solution, measurement of the amide proton chemical shifts and exchange rates, characterization of the aromatic spin systems and the internal mob ...197833043
conformational studies of neurotoxin ii from naja naja oxiana. selective n-acylation, circular dichroism and nuclear-magnetic-resonance study of acylation products.after treatment of neurotoxin ii, a component part of the venom of the middle asian cobra naja naja oxiana, with acetoxysuccinimide all five possible epsilon-acetylated-lysyl derivatives were obtained and the position of the label was established. trifluoroacetylation of both the derivatives and the parent toxin yielded, respectively, the five acetyl-penta(trifluoroacetyl)-neurotoxins ii and the hexa(trifluoroacetyl)-neurotoxin ii, which were studied by circular dichroism (cd), 1h and 19f nuclea ...197934515
effect of purified phospholipases on the binding of tetrodotoxin to axon plasma membrane.the role of phospholipids in the binding of [3h]tetrodotoxin to garfish olfactory nerve axon plasma membrane was studied by the use of purified phospholipases. treatment of the membranes with low concentrations of either phospholipase a2 (crotalus adamanteus and naja naja) or phospholipase c (bacillus cereus and clostridium perfringens) resulted in a marked reduction in tetrodotoxin binding activity. a 90% reduction in the activity occurred with about 45% hydrolysis of membrane phospholipids by ...197939172
conformation of cobrotoxin in aqueous solution as studied by nuclear magnetic resonance.the 270-mhz proton nmr spectra of cobrotoxin from naja naja atra were observed in 2h2o solution. the pka value (5.93) of his-32 is slightly lower than the pka value (6.65) of the reference model of n-acetylhistidine methylamide, because of the electrostatic interaction with arg-33 and asp-31. the pka value (5.3--5.4) of his-4 is appreciably low, because of the interaction with the positively charged guanidino group possibly of arg-59. the hydrogen-deuterium exchange rates in 2h2o solution were m ...197943248
localization of a protein antigen in the chicken spleen. effect of various manipulative procedures on the morphogenesis of the germinal centre.the time course of the localization of a protein antigen human serum albumin (hsa) into the chicken spleen after intravenous injection is analysed. localization within seconds to the region surrounding the schweigger-seidel sheaths is accomplished by hsa complexes with chicken anti-hsa or by heat aggregated hsa. the localization of soluble hsa has to await the synthesis of sufficient chicken anti-hsa to accomplish localization to the same white pulp sites in the spleen at 25-30 hours after injec ...197546839
cobra venom factor: evidence for its being altered cobra c3 (the third component of complement).evidence is presented that cobra venom factor, the anticomplementary protein in naja naja venom, is modified cobra c3 (the third component of complement). antiserum to the cobra venom factor cross reacts with human c3. a protein in cobra serum reacts strongly with antiserum to the venom factor and the former protein, like human c3, is converted by incubation of cobra serum with endotoxin, hydrazine, or simple storage at 37 degrees c. incubation of cobra venom factor with cobra serum destroys the ...197656780
[production of antiserum to neurotoxin-2 from naja naja oxiana cobra venom and reaction with the toxin].antiserum to neurotoxin-2 from the venom of the cobra was obtained by immunization of rabbits via the injection of the toxin into the lymphatic nodes and by two re-immunizations via the injection of the toxin into the blood and intramuscularly. using scores of micrograms of the toxin, specific antisera with high antibody titer were obtained. in spite of high specificity of separate stages of the reactions, using indirect immune fluorescence technique, no specific fluorescence was found in the en ...197992118
preparation of highly potent naja naja atra (formosan cobra) antivenin.as the preparation of high titer antiserum against naja naja atra venom is a time-consuming process, attempts were made to develop a immunization procedure for producing highly potent antiserums within a short period. rabbits were immunized for 12 weeks with (1) whole venom as used routinely in our institute, (ii) whole venom adsorbed on carboxymethyl-cellulose (cmc) and mixed with freund's complete adjuvant and (iii) neurotoxin adsorbed on cmc and adjuvant mixture followed by cmc-whole venom-ad ...1978115651
production of potent antivenin against cobra venom with conjugated-cobrotoxin.cobra venom (naja naja atra) and its fractions obtained by ammonium sulfate precipitation were subjected to chromatography on cm-cellulose colum. a highly purified cobrotoxin obtained by the repeated chromatography on preparative cm-cellulose column was 6.7 times more toxic than the original cobra venom. the toxin was detoxified by a bifunctional reagent, glutaraldehyde, to about 99.8% and utilized for immunization in animals. mice received 4 weekly immunization with detoxified cobrotoxin and ch ...1979121068
inactivation of (na-++k-+)-stimulated atpase by a cytotoxic protein from cobra venom in relation to its lytic effects on cells.the mechanism of action of the cytotoxic protein p6 isolated from cobra venom (naja naja) which shows preferential cytotoxicity particularly to yoshida sarcoma cells has been studied by its effects on the membrane-bound enzyme (na-++k-+)-atpase (atp phosphohydrolase, ec 3.6.1.3) of a variety of cell systems. evidence obtained with yoshida sarcoma cells, dog and human erythrocytes and three tissue culture cell lines kb (human oral carcinoma), hela (human cervix carcinoma) and l-132 (human lung em ...1975124601
the effect of a cardiotoxic component of the venom of the indian cobra (naja nigricollis) on the subcellular structure and function of heart muscle. 1976133248
the lipid requirement of the (ca2+ + mg2+)-atpase in the human erythrocyte membrane, as studied by various highly purified phospholipases.1. when complete hydrolysis of glycerophosphlipids and sphingomyelin in the outer membrane leaflet is brought about by treatment of intact red blood cells with phospholipase a2 and sphingomyelinase c, the (ca2+ + mg2+)-atpase activity is not affected. 2. complete hydrolysis of sphingomyelin, by treatment of leaky ghosts with spingomyelinase c, does not lead to an inactivation of the (ca2+ + mg2+)-atpase. 3. treatment of ghosts with phospholipase a2 (from either procine pancreas of naja naja veno ...1977137746
studies on the reproductive cycle on the female cobra, naja naja. ii. in vitro ovarian steroid synthesis. 1977142685
reversible neuromuscular blockade by modified neurotoxin from naja naja siamensis (39875). 1977143665
organization of phospholipids in human red cell membranes as detected by the action of various purified phospholipases.1. the action of eight purified phospholipases on intact human erythrocytes has been investigated. four enzymes, e.g. phospholipases a2 from pancreas and crotalus adamanteus, phospholipase c from bacillus cereus, and phospholipase d from cabbage produce neither haemolysis nor hydrolysis of phospholipids in intact cells. on the other hand, both phospholipases a2 from bee venom and naja naja cause a non-haemolytic breakdown of more than 50% of the lecithin, while sphingomyelinase c from staphyloco ...1975169915
effects of some immunosuppressive procedures on myasthenia gravis.clinical observations. a total of 53 mg patients have been treated with different immunosuppressive methods (alone or combined) with the following effects: thymectomy was performed in 38 patients. the improvement was excellent in 15, and moderate or uncertain in 20. in three patients severe long-lasting deterioration followed the operation. acth treatment (n=32): initial deterioration during the 5-7 days of heavy acth treatment (1000 iu) was followed by an improvement lasting on an average 4 mon ...1976183592
the absence of antagonism between extracts of clinacanthus nutans burm. and naja naja siamensis venom.clinacanthus nutans burm, a herb reputed in thailand and malaysia to be "snakebite antidote" has been tested in vitro and in vivo for antivenin activity. the aqueous extract of c. nutans leaves has been found to have no effect on the inhibition of neuromuscular transmission produced by purified naja naja siamensis neurotoxin in isolated rat phrenic-nerve diaphragm preparations. the extract of c. nutans, when given orally or intraperitoneally, are ineffective in prolonging the survival time of ex ...1977199949
azidophenantridinium compounds as photoaffinity labels of cholinergic proteins.the synthesis of diazidopropidium and diazidoethidium is described. the applicability of these compounds as photoaffinity labels for cholinergic proteins has been investigated: diazidopropidium inhibits neuromuscular transmission. this inhibition is reversible if the compound is applied in the dark but becomes irreversible after irradiation with white light. inhibition is accompanied by a disappearance of miniature endplate potentials. electrophysiological analysis of this effect indicates that ...1990208646
acetylcholine receptors in the ciliary ganglion and in the iris muscle of the chick: specific binding and effect on the synaptic transmission of the neurotoxin from naja naja siamensis.1 a specific binding of naja naja siamensis neurotoxin was found both in the iris and in the ciliary ganglion of the chick. 2 naja-toxin (125 nm) caused a complete block of the iris muscle contraction induced by carbamylcholine. 3 naja-toxin had a different effect on the two neuronal populations present in the ganglion: it blocked the synaptically evoked response of the ciliary cells, while the response of the choroid ones was only slightly reduced. the effects were the same in a wide range of c ...1979222384
epr and fluorescence study of interaction of naja naja oxiana neurotoxin ii and its derivatives with acetylcholine receptor protein from torpedo marmorata. 1979227728
influence of charge on the inactivation of membrane bound (na+ + k+)-atpase of yoshida sarcoma cells by inhibitor proteins from cobra venom.inactivation of (na+ + k+)-atpase of yoshida sarcoma cells and beef brain microsomes by phospholipase a2 and a cytotoxin p6 from snake venom has been examined in relation to their activity to degrade phospholipids. cytotoxin p6 which was most basic and devoid of phospholipase activity was most effective in inhibiting the (na+ + k+)-atpase of yoshida sarcoma cells. phospholipase a2 from naja naja which was most active in degrading phospholipids was least effective in inhibiting (na+ + k+)-atpase ...1976233302
studies on the annual reproductive cycle of the female cobra, naja naja. i. seasonal variation in plasma cholesterol. 1975241552
binding of thiamine to nicotinic acetylcholine receptor in torpedo marmorata and the frog end plate.thiamine was found to bind to the isolated nicotinic receptor (nachr) from torpedo marmorata (kd = 3--5 x 10(-5) m). the binding was reversible and inhibited by alpha-neurotoxin from naja naja siamensis. acetylcholine binding was not inhibited by thiamine. when thiamine (5 x 10(-4) m) was applied to frog sartorius muscles a decrease of miniature end plate potential amplitudes was seen. this effect was readily reversible after the perfusion fluid of the muscle was changed to normal ringer solutio ...1978307899
comparison of phospholipase activity with direct and indirect lytic effects of animal venoms upon human red cells.1. the venoms of 22 species of arthropods, saurians, elapids and crotalids were studied concerning the phospholipase activity and the presence of a direct and an indirect lytic effect upon human red cells. 2. the venoms from the spiders latrodectus and "tarantula", and the venoms from the scorpions of the genus centruroides are not haemolytic and do not have phospholipase activity. 3. only the venoms of apis mellifera and naja naja siamensis have shown direct lytic effect. 4. all other venoms st ...1979318305
immunoglobulins in myasthenia gravis: effect of human lymph igg 3 and f (ab')2 fragments on a cholinergic receptor preparation from torpedo marmorata.lymph igg from patients with myasthenia gravis was shown to inhibit the binding of radio-labelled naja naja siamensis alpha-neurotoxin to membrane fragments from the electric organ of torpedo marmorata. this effect could be related to igg subclass 3 and to the f(ab')2 fragment. these findings confirm the involvement of antibodies of postsynaptic structures in myasthenia gravis.1977404156
purification and characterization of nerve growth factor from the venom of bungarus multicinctus.the nerve growth factor from bungarus multicinctus venom was purified by means of successive chromatography on sephadex g-50, carboxymethyl-cellulose, carboxymethyl-sephadex c-50 and sephadex g-50. the purified nerve growth factor was homogeneous by polyacrylamide disc gel electrophoresis. the molecular weight was estimated to be about 21 000 by gel filtration. compared with the nerve growth factors from the venoms of other elapidae, namely naja naja and naja naja atra, this protein showed high ...1978417735
cobra venom acetylcholinesterase. purification and molecular properties.acetylcholinesterase from cobra (naja naja oxiana) venom has been purified by affinity chromatography to an homogeneous state, as ascertained by sodium dodecylsulfate/polyacrylamide gel electrophoresis and sedimentation analysis. the specific activity of the preparation was 5000 iu/mg with acetylcholine as substrate. unlike acetylcholinesterases from insoluble cell structures, the native molecule of the cobra venom enzyme consists of a single polypeptide chain of molecular weight 67,000 +/- 2000 ...1979456362
poikilotherms as reservoirs of q-fever (coxiella burnetii) in uttar pradesh.water snakes (natrix natrix), rat snakes (ptyas korros), cobras (naja naja), pythons (python molurus), tortoises (kachuga sp.), plankton fish (cirrhina mrigala), frogs (rana tigrina), toads (bufo sp.) and monitors (varanus indicus) were screened for evidence of q-fever infection by the capillary agglutination test on sera to detect antibodies and/or by attempts to demonstrate coxiella burnetii in spleen and liver samples. sero-reactors were observed among water and rat snakes, pythons and tortoi ...1979459042
photoaffinity derivatives of alpha-bungarotoxin and alpha-naja naja siamensis toxin. 1979467650
influence of enzymatic phospholipid cleavage on the permeability of the erythrocyte membrane. i. transport of non-electrolytes via the lipid domain.in order to further elucidate the influence of membrane lipids on transport via the lipid domain of the erythrocyte membrane, simple non-electrolyte diffusion was investigated by tracer flux measurements in whole cells after cleavage of up to 65% of phosphatidylcholine or sphingomyelin by phospholipase a2 from naja naja, or by sphingomyelinase. a new type of labelled model non-electrolyte was used in this study, readily available by reacting a non-labelled thiol with a labelled alkylating sh-rea ...1979486449
influence of enzymatic phospholipid cleavage on the permeability of the erythrocyte membrane. ii. protein-mediated transfer of monosaccharides and anions.in order to investigate the influence of membrane lipids on transport via the protein domain of the erythrocyte membrane, a number of facilitated diffusion processes was studied by tracer flux techniques in whole cells after cleavage of up to 65% of the phosphatidylcholine or the sphingomyelin by phospholipase a2 from naja naja or bee venom, or by sphingomyelinase, respectively. the mediated fluxes of l-arabinose, which is transported by the glucose carrier, and of l-lactate, which uses a specif ...1979486450
asymmetric manipulation of the membrane lipid bilayer of intact human erythrocytes with phospholipase a, c, or d induces a change in cell shape.changes in the membrane morphology and phospholipid content of human erythrocytes were determined after incubation of intact cells with each of various exogeneous phospholipases (plases). plase a2 from naja naja or bee venom induced crenation of the cells in parallel with hydrolysis of the membrane phosphatidylcholine (pc). this crenated cell shape was reversed to a biconcave disc or cup-like form by a further treatment with lysophospholipase. in contrast, bacterial plase c from clostridium perf ...1979521437
effect of five thai snake venoms on coagulation, fibrinolysis and platelet aggregation.the effects of five thai snake venoms--malayan pit viper--mpv (ancistrodon rhodostoma); russell's viper--rvv (vipera russelli); cobra--cv (naja naja); king cobra--kcv (naja hannah) and banded krait--bkv (bungarus fasciatus)--on blood coagulation fibrinolysis and platelet aggregation were studied. mpv has strong thrombin-like coagulant action. rvv has activating effect most probably on factor x. other three venoms--cv, kcv and bkv have been shown to be anti coagulant, on both intrinsic and extrin ...1979524153
[purification by affinity chromatography and properties of the acetylcholinesterase of formosan cobra (naja naja atra) venom (author's transl)].the acetylcholinesterase was purified by cm-sephadex chromatography and affinity chromatography on sepharose bound m-[6-(6-aminocaproylamino)caproylamino]phenyltrimethylammonium bromide. the purified enzyme was obtained with a specific activity of 5470 u/mg (1160-fold purification) and a 89% yield. the molecular weight of the native enzyme was estimated to be 144,000. the enzyme is split into two subunits of approximately equal molecular weight (mr 69,000) by sds treatment. it is a glycoprotein ...1979536451
conformational prediction for snake venom toxins and laser raman scattering of a cardiotoxin from taiwan cobra (naja naja atra) venom.secondary structure regions in snake venom toxins were predicted using the prediction method of chou and fasman (chou, p. y., and fasman, g. d. (1974), biochemistry 13,222) and an averaging scheme assuming structural homology in each type of toxins. the results indicate that, in general, snake toxins contain only some beta-sheet regions and beta bends. the content of secondary structures thus predicted does vary to some extent. the predicted results correlate well with conclusions from physicoch ...1977560203
an improved method for the isolation from naja naja venom of cobra factor (cof) free of phospholipase a.an improved method is reported for the isolation from cobra (naja naja) venom of cobra factor (cof), the anticomplementary protein which is derived from cobra c3. sequential chromatography on deae-sepharose, sephacryl-s200, and finally hydroxylapatite yielded 6.25 mg cof per gram of crude venom. the purified cof had 1 unit of functional anticomplementary activity per 1--2 micrograms of protein, and was homogeneous on gradient and non-reduced sodium dodecyl sulphate (sds) polyacrylamide gel elect ...1979574149
conformational stability of a snake cardiotoxin.a snake cardiotoxin from the venom of the formosan cobra, naja naja atra, is a basic polypeptide. the protein can be denatured in 6.0 m guanidine hydrochloride or at elevated temperatures. its conformation remains virtually the same in solvents of lower polarity than water such as 1, 2-ethanediol or 1-propanol and 1, 2-ethanediol (1:1 v/v). the circular dichroism spectrum is atypical in water in that the peptide chromophores show a small negative cd band at 214 nm and a large positive one at 195 ...1977591177
membranes rich in acetylcholine receptor: characterization and reconstitution to excitable membranes from exogenous lipids.characterization of acetylcholine-receptor-enriched membranes from torpedo californica electric tissue by negative-staining electron-microscopy and by lipid analysis is described. the protein/lipid ratio is 70%/30%. the lipids consist of 70% phospholipids (46% phosphatidylcholine, 31% phosphatidylethanolamine, 14% phosphatidylserine, 7% sphingomyelin, 2% phosphatidylinositol of the phospholipids determined) and 20% cholesterol. the acetylcholinesterase-enriched membranes show a similar compositi ...1978639824
location of disulfide bridges in cardiotoxin from the venom of formosan cobra (naja naja atra).the location of the four disulfide bridges in cardiotoxin from the venom of the formosan cobra, naja naja atra, was determined by isolating cystine-containing peptides from the enzymic and partial acid hydrolyzates of the intact toxin. the results indicate that the disulfide bridges are formed by half cystine residues 3--21, 14--38, 42--53, and 54--59. the amino acid sequence at the position 48--49 was revised to -leu-val- instead of val-leu- as reported previously.1978649257
an electron microscopic study of the adductor externus superficialis muscle associated with the venom gland of the cobra (naja naja).the adductor externus superficialis muscle closely envelops the venom gland in the cobra (naja naja). only twitch fibres are present in the muscle, supporting the view that the muscle is concerned with the rapid evacuation of venom. 'satellite' cells are readily observed in relation to the muscle fibres.1978649503
phospholipase a2 contamination of cobra venom factor preparations. biologic role in complement-dependent in vivo reactions and inactivation with p-bromophenacyl bromide.cobra venom factor (cof), the anticomplementary protein in naja naja cobra venom, is usually purified by sequential ion exchange and gel filtration chromatography. cof prepared in this manner contains small but significant quantities of phospholipase a2 activity. this acyl hydrolase activity can be simply and efficiently removed on a large scale by treatment of cof with p-bromophenacyl bromide (bpb), an irreversible modifier of the histidine residue in the active site of phospholipase a2. bpb tr ...1978655262
mechanism of phospholipase a2 action toward mixed micelles of detergent and phospholipids.phospholipase a2 from cobra venom (naja naja naja) is a homogeneous, heat-stable enzyme that has a monomer molecular weight of only 11,000 and contains one histidine and one tryptophan residue. this enzyme acts optimally on phospholipids contained in mixed micelles with the nonionic detergent triton x-100; the interactions of this detergent with phospholipid in the mixed micelles have been elucidated with 1h- and 13c-nmr. in reacting, the enzyme first associates with the mixed micelle and then e ...1978665362
phosphatidylcholine mobility in liver microsomal membranes.purified phosphatidylcholine exchange protein from bovine liver was used to exchange rat liver microsomal phosphatidylcholine for egg phosphatidylcholine. it was found that at 25 and 37 degrees c rat liver microsomal phosphatidylcholine was completely and rapidly available for replacement by egg phosphatidylcholine. in contrast, phosphatidylcholine in vesicles prepared from total microsomal lipids could only be exchanged for about 60%. at 8 and 0 degrees c complex exchange kinetics were observed ...1978667042
exploring the action and specificity of cobra venom phospholipase a2 toward human erythrocytes, ghost membranes, and lipid mixtures.we have investigated the action and substrate specificity of phospholipase a2 (ec 3.1.1.4) purified from cobra venom (naja naja naja) toward intact and triton-solubilized human erythrocytes, toward ghost membranes, and toward extracted ghost lipids in mixed micelles with triton x-100. we have found that: (i) phospholipids in the outer surface of intact erythrocytes are extremely poor substrates for the phospholipase, (ii) phospholipids in ghost erythrocyte membranes and in triton-solubilized ery ...1978670181
a simple method for purification of cardiotoxin from indian cobra (naja naja naja) venom. 1978684770
clinical observations on glucocorticoids in cobra envenomation.a clinical trial of corticosteroid treatment in five cases of cobra, naja naja, bite with systemic poisoning is reported. the results reveal that corticosteroid had no demonstrable beneficial effect in the neurotoxic poisoning of the cobra. specific antivenom is the most important therapeutic agent for systemic poisoning. the combination of antivenom and corticosteroid had no effect on the development of local necrosis.1978705419
studies on neurotrophic regulation of murine skeletal muscle.1. a quantitative comparison was made of the effects of the paralysis caused by botulinum toxin (botx) type a with those of surgical denervation on the development of tetrodotoxin (ttx) resistant action potentials and of extrajunctional acetylcholine (ach) receptors in rat and mouse skeletal muscle.2. after surgical denervation, ttx resistant action potentials were present in all fibres on the third day and their rate of rise and amount of overshoot reached peak values at the fifth day. botx poi ...1978722508
neuromuscular effects of fractions isolated from the venom of the thailand cobra, naja naja siamensis. 1978725955
[interaction of cardiotoxin from the venom of the cobra naja naja oxiana with phospholipid membrane model systems].surface activity of cardiotoxin from the venom of cobra naia naja oxiana and an acetylated analog of the cardiotoxin was investigated on the water-air interface. the interaction of these substances with lipid monolayers and bimolecular membrane was also studied. it was shown that on the water-air interface cardiotoxin can form two different types of monolayers with different conformations of molecules. cardiotoxin is found to form complexes with phospholipids due to interaction of positive charg ...2017739993
the markers of pig heart mitochondrial sub-fractions. ii. - on the association of malate dehydrogenase with inner membrane.malate dehydrogenase, reputed to be a soluble matricial enzyme, is shown to be also strongly associated with the inner membrane, in pig heart mitochondria. repeated sonications, water washes, freezing-thawing cycles are not very effective to remove malate dehydrogenase activity from inner membranes, which whatever the treatment, remains important. this activity is only partly solubilized by the substrates, malate or oxaloacetate. high ionic strength treatments by either nacl-carbonate or 3m kcl ...1978753379
comparison of the nerve growth factor proteins from cobra venom (naja naja) and mouse submaxillary gland.the nerve growth factors (ngf's) isolated from cobra venom (naja naja) and mouse submaxillary gland are closely related proteins. they are structurally similar in that about 60% of their amino acid residues are identical (hogue-angeletti, r. a., frazier, w. a., jacobs, j. w., niall, h.d., and bradshaw, r. a. (1976), biochemistry, preceding paper in this issue). they are functionally similar in that they both elicit maximum neurite outgrowth from chick embryonic dorsal root ganglia at the same pr ...1976813760
[structural analysis of lethal snake venom neurotoxins by change transfer].among the two trp and the unique tyr present in the amino-acid sequence of the neurotoxin of naja naja philippinensis, only one trp is reactive in intermolecular charge transfer experiments, using organic electron acceptors. in the reference toxin-alpha of naja nigricollis, neither the single trp nor the tyr, both invariant and essential for lethality, are available for charge transfer. a minor and very weak complex is obtained, which is assumed to be initiated by an exposed his. although fully ...1976825318
transverse asymmetry of phospholipids in subcellular membranes of rat liver.subcellular membranes isolated from rat liver in a form impermeable to macromolecules were treated with phospholipase a2 from naja naja venom. the phosphatidylserine, phosphatidylethanolamine and about half of the phosphatidylcholine of microsomes, golgi membranes, inner mitochondrial membranes, lysosomes and nuclear membranes were hydrolyzed. it is proposed that these phospholipids are localized in the outer surface of the membrane bilayer, which represents the cytoplasmic side in the living ce ...1977831804
inhibition of virus-induced plaque formation by atoxic derivatives of purified cobra neurotoxins.venom from naja naja siamensis was resolved into 16 toxic and nontoxic fractions by chromatography on sp-sephadex, c-25. the principal neurotoxin preparations were chromatographically and electrophoretically homogeneous. of the purified constituents, only the principal neurotoxin and minor neurotoxins were precursors of inhibitors of plaque formation among baby hamster kidney fibroblasts infected with semliki forest virus.1977836894
primary structures of cardiotoxin analogues ii and iv from the venom of naja jaja atra.cardiotoxin analogues ii and iv were isolated from the venom of naja naja atra by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the venom contains at least four cardiotoxin analogues that account for about 54% of the weight of the lyophilized crude venom. these four cardiotoxin analogues, named cardiotoxin analogues i, ii, iii, and iv, show strong cytotoxicity to yoshida sarcoma cells but the lethal toxicity is one-order less. these toxins contain 60 amino acid residue ...1977849468
optical activity and conformation of cobra neurotoxin.cobra neurotoxin from formosan cobra (naja naja atra) venom is a compact globular protein having an intrinsic viscosity of 4.5 ml/g. the protein is stable in 7.5 m urea but can be denatured in 4.1 m guanidine hydrochloride or at elevated temperature (above 70 degrees c). its conformation remains virtually the same in solvents of lower polarity than water such as 1,2-ethanediol or a mixed solvent of 1-propanol-1,2-ethanediol-water (5:1:1 by volume). the circular dichroism spectrum is "atypical" i ...1977870027
preparation of toxoids from the venoms of pakistan species of snakes. (naja naja, vipera russellii and echis carinatus). 1977875234
morphological study of lesions induced by snake venoms (naja naja and agkistrodon piscivorus) in the lung and cremaster vessels of rats.the morphological effects of two snake venoms, n. naja and a. piscivorus, and of the direct lytic factor and phospholipase-a, compounds purified from n. naja crude venom, were investigated on lung and cremaster vessels of rats. the microcirculation of the rat reacts to these two venoms differently: n. naja produces congestion, haemolysis and increased vascular permeability, whereas a. piscivorus causes these alterations, plus haemorrhage and thrombosis. direct lytic factor elicits reponses simil ...1977881630
studies of nicotinic acetylcholine receptor protein from rat brain. ii. partial purification.the pharmacological specificity of the binding of 125i-labeled alpha-bungarotoxin to a 1% emulphogene bc-720 extract of a rat brain particulate fraction has been investigated. the extract contains a component which possesses the binding characteristics of a nicotinic acetylcholine receptor protein. the crude soluble acetylcholine receptor protein was purified by affinity chromatography utilizing the alpha-neurotoxin of naja naja siamensis as ligand and 1.0 m carbamylcholine chloride as eluant. a ...1977884157
interrelation between two anticomplement cobra venom factors isolated from crude naja naja cobra venom.two moieties occurring in crude naja naja cobra venom were found to possess anticomplement activity. both materials possessed similar molecular weights and specific activities but dissimilar elution profiles upon ion-exchange chromatography. the anticomplement activities of these materials were maintained upon digestion with neuraminidase, and their elution profiles from cation-exchange chromatography became identical after this treatment. it was concluded that the differences between the two an ...1977886456
[effect of diacid analogs of phosphatidylcholines on phospholipase a2 activity from naja naja venom]. 1977889937
nicotinic cholinergic receptors in rat brain identified by [125i]naja naja siamensis alpha-toxin binding. 1977890462
discrimination between nicotinic receptors in vertebrate ganglia and skeletal muscle by alpha-bungarotoxin and cobra venoms.1. we have used snake neurotoxins, alpha-bungarotoxin and venoms from naja naja siamensis and naja nivea, to distinguish the nicotinic receptors of ganglia from those of skeletal neuromuscular junctions. 2. these neurotoxins failed to block responses of isolated guinea-pig longitudinal muscle with adherent myenteric plexus to the nicotinic agonists, nicotine or dimethylphenylpiperazinium, to acetylcholine (ach), or to electrical field stimulation. 3. the toxins failed to affect responses of the ...1977894538
effects of aliphatic dicarboxylic acids on neuromuscular inhibition produced by naja naja siamensis toxin 3 and d-tubocurarine. 1977906030
neuromuscular blocking actions of neurotoxins isolated from laticauda semifasciata, naja naja and naja naja atra--a comparative assay--. 1977916390
effects of local anaesthetics on phospholipases.1. the effects of six local anaesthetics have been studied on the activities of soluble phospholipases a2 (ec 3.1.1.4) and lysophospholipase (ec 3.1.1.5). 2. phospholipase a2 activity in human seminal plasma towards sonicated radioactively-labelled phosphatidylethanolamine was slightly stimulated a low and inhibited at high concentrations of all anaesthetic compounds employed. the order of decreasing potency was chlorpromazine, dibucaine, tetracaine, lidocaine, cocaine and procaine. in line with ...1976952985
amino acid sequence of cardiotoxin from the venom of naja naja atra. 1976955081
nicotinic acetylcholine receptor from rat brain. solubilization, partial purification, and characterization.nicotinic acetylcholine receptor protein (nachr) has been solubilized from rat cerebral cortices by extracting a crude membrane fraction with the nonionic detergent triton x-100 (polyoxyethylene-p-t-octylphenol). the solubilized nachr was partially purified by affinity chromatography (naja naja siamensis alpha-toxin affinity arm, linked to sepharose 4b) and characterized by binding of 125i-labeled alpha-bungarotoxin. the reaction of labeled toxin and nachr appears to be second order with a rate ...1976977572
morphological observations on motor end-plates in rabbits with experimental myasthenia.the morphology of motor end-plates in rabbits immunized with torpedo nicotinic acetylcholine receptor (nachr) has been studied by light and electron microscopy. rabbits were studied either after one period of paralysis, some in parallel with electrophysiological recordings of mepps and epps and of naja naja alpha-neurotoxin binding properties or after recovery followed by a second paralysis. changes in the sub-neural apparatus were noted after cholinesterase staining only in the latter group. ul ...1976978217
the amino acid sequence of cardiotoxin-analogue iv from the venom of naja naja atra. 1976992063
the primary structure of toxin b from the venom of the indian cobra naja naja. 1976992083
amino acid sequence of cardiotoxin-analogue ii from the venom of naja naja atra. 1976999683
isolation and characterization of nerve growth factor from the venom of naja naja atra.nerve growth factor was isolated from the venom of naja naja atra by ion exchange and gel permeation chromatography and was found to be homogeneous by disc gel electrophoresis. the molecular weight was estimated to be approximately 20,000 by gel filtration and 22,000 by ultracentrifugation. this protein, which showed an isoelectric point of ph 7.02, probably consists of two subunits of equal molecular weight which are held together or interact with each other noncovalently. the biological activi ...19761002678
[effect of central asian cobra (naja naja oxiana) venom on the biosynthesis of nucleic acids and protein in animal cells].cobra poison at a dose of 4 microng/kg of body weight intensified the 3h-thimidine incorporation into dna of mice liver tissue; 20-40 microng/kg of the poison inhibited the incorporation. single intraperitoneal administration of high doses of cobra poison (50-150 microng/kg) decreased the incorporation of 14c-thimidine into dna 1.2-1.9-fold. little doses of the poison increased the incorporation of 14c-hydrolysate of chlorella protein into proteins of liver cells and the high doses inhibited thi ...20131027229
[acetylcholinesterase of cobra venom. determination of concentration of active sites].o-nitrophenyl dimethylcarbamate and organophosphorus inhibitors o-n-propyl-p-nitrophenyl methylphosphonate, o-n-butyl-p-nitrophenyl methylphosphonate, o,o-diethyl-p-nitrophenyl phosphate, o-n-butyl-s-(beta-ethylmercaptoethyl) methylthiophosphonate, methysulphate of o,o-diethyl-s-(beta-phenyldimethylammoniumethly) thiophosphate were used in the titration of acetylcholinesterase active site concentratration in naja naja oxiana venom. no side reactions with the acetylcholinesterase molecule as well ...19761030638
prevention and suppression by azathioprine of venom-induced protein-losing gastropathy in dogs.irrigation of the dog's oxyntic glandular mucosa contained in a chronically prepared, vagally denervated, separated pouch of the dog's stomach with a solution (0.5 mg ml-1) of lyophilized venom of the hooded cobra (naja naja) increases the permeability of the mucosa. if irrigation with venom solution is repeated at weekly intervals, the mucosa responds with increasing plasma-shedding which reaches a peak of 1-2 ml min-1 from roughly 60 cm2 of mucosa in 4-6 weeks. plasma shedding in response to i ...19761062810
photoaffinity labeling and quaternary structure of the acetylcholine receptor from torpedo californica.membrane fragments from electric tissue of torpedo californica containing nicotinic acetylcholine receptor are composed of four different polypeptide chains with molecular weights of 40,000 (alpha), 48,000 (beta), 62,000 (gamma), and 66,000 (delta). the alpha and beta chains are still present in all and gamma and delta in some of the receptor preparations after triton x-100 extraction and purification by affinity chromatography. all components of the receptor react covalently with the photoaffin ...19761066671
comparative studies on cytotoxin from the indian cobra venom and cardiotoxin from the formosan cobra venom, with special reference to the effect on the growth of ehrlich ascites tumor cells in mice. 19761068210
[the blocking action of snake venom polypeptides on the cholinergic mechanisms of leech dorsal muscle].the blocking action of alpha-polypeptides from the venoms of elapid snakes (bungarus multicinctus and naja naja siamensis) was studied on leech dorsal muscle. it was shown that these neurotoxins failed to inhibit the responses to mononitrogen cholinomimetics (acetylcholine, nicotine, carbamylcholine, etc.). the capacity of neurotoxins to inhibit the responses to the bisquaternary cholinommimetics depended upon the length of the molecule. the neurotoxins were active against the "shorter" cholinom ...19751111642
blockade of acetylcholine receptors: a model of myasthenia gravis.in order to block acetylcholine receptors of muscle, the alpha toxin of the formosan cobra (naja naja atra) was given intravenously to rats. electrophysiological and pharmacological changes typical of myasthenia gravis were recorded, including decremental responses to repetitive stimuli, curare sensitivity, neostigmine reversal, and posttetanic phenomena. this model supports the concept that a reduction of available acetylcholine receptors may play an important role in myasthenia gravis.19751145181
amino acid sequence of cardiotoxin-analogue i from the venom of naja naja atra. 19751147930
the complete amino acid sequence of a cardiotoxin from the venom of naja naja (cambodian cobra).the complete amino acid sequence of a small, basic protein with cardiotoxic activity is described. this toxin, designated naja naja f8, was isolated from the venom of naja naja, of cambodian origin, by gel filtration on sephadex g-75 followed by gradient ion exchange chromatography on bio-rex 70. the cardiotoxin f8, molecular weight 6727 from amino acid composition, consists of 60 amino acids in a single peptide chain cross-linked by four disulfide bridges and is devoid of histidine, tryptophan, ...19871148180
effect of atropine in reducing plasma protein shedding by the canine oxyntic glandular mucosa induced by topical irrigation with histamine or cobra venom.the shedding of plasma protein by the canine oxyntic glandular mucosa induced by topical irrigation of the mucosa with a solution of histamine after the gastric mucosal barrier is broken is reduced by intravenous administration of atropine. plasma shedding induced by repeated irrigation of the normal mucosa with solutions of naja naja venom is likwise reduced by intravenous atropine. the nature of atropine-sensitive component of plasma shedding is unknown.19751150023
evidence for endocytotic uptake of cobra neurotoxin in mouse skeletal muscle.an isolated 3h-labelled neurotoxin from naja naja siamensis binds irreversibly to the extensor digitorum longus muscle of the mouse in vitro. the binding consists of an adsorption to cholinergic receptors and of a slower temperature sensitive binding mechanism. the slow binding is markedly stimulated by the presence of cationic proteins (protamine, histone and polylysine) and is blocked at low temperature (+4 degrees c). vinblastine and colchicine inhibit the stimulatory effect of protamine on t ...19751159415
the cytotoxins of cobra venoms. isolation and partial characterization.eight basic proteins which lyse virus-transformed mouse fibroblasts in culture have been isolated from the venoms of six asian naja naja subspecies. these cytotoxins appear to represent an homologous series of proteins, all within the molecular weight range of 7000-8000. they have been divided into three arbitrary types on the basis of amino acid composition, electrophoretic mobilities and elution order upon ion-exchange chromatography. the rate at which the toxins effect cell lysis: (1) appears ...19751170892
relation between various phospholipase actions on human red cell membranes and the interfacial phospholipid pressure in monolayers.the action of purified phospholipases on monomolecular films of various interfacial pressures is compared with the action on erythrocyte membranes. the phospholipases which cannot hyorolyse phospholipids of the intact erythrocyte membrane, phospholipase c from bacillus cereus, phospholipase a2 from pig pancreas and crotalus adamanteus and phospholipase d from cabbage, can hydrolyse phospholipid monolayers at pressure below 31 dynes/cm only. the phospholipases which can hydrolyse phospholipids of ...19751174576
amino-acid sequence of toxin iii of naja haje.the complete amino acid sequence of toxin iii of naja haje (72 residues) has been established mainly by use of a protein sequenator (identification of 70 residues). the two c-terminal residues have been determined by digestion with carboxypeptidases a and b. addition of succinylated protein or peptide greatly improved the performance of the sequenator for the edman degradation of peptides: on one peptide (39 residues) degradation went to step 34 with a protein program and on two peptides (10 and ...19751183429
further studies on the binding properties of cobra neurotoxin to cholinergic receptors in mouse skeletal muscle.preparations of 3h-monoacetylated derivatives of naja naja siamensis neurotoxin siamensis 3 were found to be resistant to degradation and deacetylation during in vitro muscle incubation. a low rate of free 3h-acetate (less than 0.4%) was present in the preparations, but should not interfere with the binding of toxin to cholinergic receptors in mouse extensor digitorum longus muscles in vitro. the binding of toxin to cholinergic receptors in mouse extensor digitorum longus muscle was essentially ...19751185161
characterization and physical properties of the major form of phospholipase a2 from cobra venom (naja naja naja) that has a molecular weight of 11,000.the major form of phospholipase a2 from cobra venom (naja naja naja) was prepared in 30% yield and was homogeneous on polyacrylamide gel electrophoresis with and without sodium dodecyl sulfate and on sephadex g-100 chromatography. the monomer molecular weight is about 11,000 according to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. ultracentrifugation and molecular sieve techniques were employed to confirm the molecular weight and to demonstrate a concentration-dependent aggregatio ...19751194273
kinetic analysis of phospholipase a2 activity toward mixed micelles and its implications for the study of lipolytic enzymes.a detailed kinetic scheme is proposed for the action of phospholipase a2 on mixed micelles of phospholipid and surfactant: see article. where e is the enzyme, a is the mixed micelle, and b is the phospholipid substrate in the mixed micelle. this scheme takes into account quantitatively the involvement of the lipid-water interface in the action of this enzyme toward substrate in macromolecular lipid complexes. the kinetic equation for this scheme is derived and four simplifying assumptions which ...19751194274
the reaction of choline dehydrogenase with some electron acceptors.1. the choline dehydrogenase (ec 1.1.99.1) was solubilized from acetone-dried powders of rat liver mitochondria by treatment with naja naja venom. 2. the kinetics of the reaction of enzyme with phenazine methosulphate and ubiquinone-2 as electron acceptors were investigated. 3. with both electron acceptors the reaction mechanism appears to involve a free, modified-enzyme intermediate. 4. with some electron acceptors the maximum velocity of the reaction is independent of the nature of the accepto ...19751218095
sensitivity of cultured embryonic heart cells to cardiotoxin obtained from naja naja siamensis venom. 19751239834
topological asymmetry of phospholipid metabolism in rat erythrocyte membranes. evidence for flip-flop of lecithin.1. the distribution of phospholipids between inside and outside of rat erythrocyte membranes was studied by incubating the cells with phospholipase a2 from naja naja venom and sphingomyelinase from staphylococcus aureus. 2. choline-containing phospholipids were found to comprise the majority of the outer layer of the membrane. 3. the incorporation of radioactive fatty acids into phospholipids occurred predominantly at the inside of the membrane. 4. exchange of phospholipids between red cell memb ...19761245188
purification, characterization, and partial amino acid sequence of nerve growth factor from cobra venom.the nerve growth factor (ngf) from naja naja (cobra) venom has been purified and its structure compared to the ngf from mouse submaxillary gland. a two-step purification procedure has been devised, consisting of a gel filtration step in 1 m acetic acid followed by chromatography of the active pool on carboxymethylcellulose at ph 5. the molecular weight of the native protein was found to be 28000, and this value was reduced by approximately one-half under denaturing conditions. these values are c ...19761247508
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