Publications

effects of beta-bungarotoxin and naja naja atra snake venom phospholipase a2 on acetylcholine release and choline uptake in synaptosomes.	beta-bungarotoxin is a potent presynaptically acting snake venom toxin that exhibits phospholipase a2 activity. we compared the effects of beta-bungarotoxin and a less toxic snake venom phospholipase a2 on synaptosomal 3h-acetylcholine release and 3h-choline uptake. the purpose of these experiments was to study the mode by which beta-bungarotoxin inhibits 3h-acetylcholine release in this preparation. under non-depolarizing conditions, both beta-bungarotoxin and naja naja atra phospholipase a2 st ...	1986	3952766
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
positive response to edrophonium in patients with neurotoxic envenoming by cobras (naja naja philippinensis). a placebo-controlled study.	to study the ability of anticholinesterase drugs to reverse the potentially fatal paralytic effects of cobra venom, we conducted a placebo-controlled, double-blind crossover trial of intravenous edrophonium (tensilon) in 10 adults with neurotoxic envenoming caused by bites of the philippine cobra (naja naja philippinensis). there was significantly more improvement in ptosis and endurance of upward gaze after edrophonium than after placebo. five minutes after injection, the mean difference (+/- s ...	1986	3537783
selectivity and regulation in the phospholipase a2-mediated attack on cholinergic synaptic vesicles by beta-bungarotoxin.	the total fatty acid composition of purified torpedo californica electric organ synaptic vesicles was determined by glc analysis of methyl esters. limit amounts of fatty acids released by high concentrations of either beta-bungarotoxin (beta-butx) or naja naja venom phospholipase a2 (pla2) acting in deoxycholate are reported. the time and enzyme concentration dependence for beta-butx- and pla2-induced release of fatty acids from intact synaptic vesicles indicate that pla2 is 100- to 1,000-fold m ...	1986	3746303
rate-determining step in phospholipase a2 mechanism. 18o isotope exchange determined by 13c nmr.	h2(18)o isotope exchange into specifically 13c-labeled substrate was used to obtain information on the rate-limiting step in the action of the phospholipase a2 from the venom of the indian cobra (naja naja naja). incorporation of 18o was detected by the effect of 18o on 13c chemical shifts in 13c nmr. the enzymatic hydrolysis of a micellar phosphatidylcholine analogue of platelet-activating factor 1-alkyl-2-[1-13c]lauroyl-sn-glycero-3-phosphorylcholine proceeds by an o-acyl cleavage of the sn-2 ...	1986	3745162
1-stearyl,2-stearoylaminodeoxy phosphatidylcholine, a potent reversible inhibitor of phospholipase a2.	1-stearyl, 2-stearoylaminodeoxy phosphatidylcholine, a structurally modified phospholipid substrate analog exhibits potent and reversible inhibition of phospholipase a2 from cobra venom (n. naja naja). the apparent ki values determined in two different assay systems employing phosphatidylcholine-surfactant mixed micelles are in reasonable agreement (40 microm and 16 microm) and indicate that the inhibitor binds to the enzyme as much as two orders of magnitude more tightly than does dipalmitoyl p ...	1986	3755338
analysis of folding intermediates from the main toxin of naja naja samarensis containing two blocked cysteines.	the formation of folding intermediates blocked by iodoacetate from the main toxin of naja naja samarensis was monitored by fplc and the populations were identified by amino acid analyses. we have determined conditions allowing for the highest yield in the populations with two blocked cysteines. the free cysteines remaining under these conditions were labeled with iodo[14c]acetate and localized by peptide mapping in one of the products isolated by ion-exchange chromatography (nt3iii). we have als ...	1986	3699158
[effect of modification of naja naja oxiana neurotoxin ii on the stoichiometry of its complexes with acetylcholine receptor].	it was discovered that illumination of the complex formed by the solubilized acetylcholine receptor from torpedo marmorata and lys25-p-azidobenzoyl derivative of neurotoxin ii results in the appearance on the receptor of up to 4 additional binding sites. acetylcholine and neurotoxin ii, but not the long-chain neurotoxins bind specifically to these sites. the additional binding sites could be also detected after illuminating the receptor complex with other photoactivable derivatives, provided the ...	1986	3718547
[synthesis of tritium-labeled n,n-dimethyl-2-phenylaziridinium and its reaction with acetylcholinesterase].	the synthesis of tritium-labeled n,n-demethyl-2-phenylaziridinium has been described. the specific radioactivity of the product obtained was 1,06 tbq/mmole. kinetics of incorporation of this radioactive label into acetylcholinesterase of cobra venom (naja naja oxiana) has been studied at 1,05 mm ligand concentration (25 degrees c, ph 7,50. 0,15 m phosphate buffer). under these conditions two molecules of the radioactive label have been found to react with the enzyme. one molecule incorporates fa ...	1985	4074397
binding of a curarimimetic toxin from cobra venom to the nicotinic acetylcholine receptor. interactions of six biotinyltoxin derivatives with receptor and avidin.	we have reacted n-hydroxysuccinimidyl biotin with the principal curarimimetic toxin in naja naja siamensis venom, biotinylating each of the five lysine residues and the n-terminal isoleucine. the six monobiotinyl-toxins were isolated by ion-exchange chromatography, and the residue modified in each was identified by peptide mapping and amino acid analysis. we evaluated the role of each lysine in the binding of toxin to the acetylcholine receptor by measuring the affinity of each biotinyltoxin for ...	1985	3161881
action of cobra venom phospholipase a2 on large unilamellar vesicles: comparison with small unilamellar vesicles and multibilayers.	phospholipase a2 (naja naja naja) catalyzes the hydrolysis of dipalmitoyl phosphatidylcholine in small unilamellar vesicles (suvs) with a faster initial rate than in large unilamellar vesicles (luvs) and multilamellar vesicles (mlvs). for the suvs, the hydrolysis was initially faster for gel phase than liquid crystalline phase phospholipid. for both luvs and mlvs, hydrolysis was low except in a small temperature range around the thermotropic phase transition of the phospholipid. in this temperat ...	1985	3838567
affinity chromatography of phospholipase a2 from naja naja naja (indian cobra) venom.	a rapid and improved purification procedure is described for phospholipase a2 from the indian cobra, naja naja naja. the procedure is based on affinity chromatography of the venom through affi-gel blue to obtain a 9-fold purification in one step. however, as there are multiple forms of the enzyme in the venom and other proteins do bind to affi-gel blue, further purification is achieved by de-11 cellulose. finally, a minor contaminant is removed by sulfopropyl sephadex c-25 chromatography. the re ...	1985	3927524
adrenergic receptors of isolated snake atria.	cardiac adrenergic receptors in snakes were examined using an isolated atria preparation of naja naja and ptyas korros. treatments included an examination of the atrial responses to selective alpha- and beta-adrenergic agonists and antagonists. in both species, both phenylephrine and isoproterenol produced dose-dependent increases in the atrial beating rate and tension. phenylephrine-induced increases were characterized with a high affinity and low affinity components. these positive chronotropi ...	1985	2861969
amino acid sequence of a cardiotoxin-like basic polypeptide (clbp) with low cytotoxic activity isolated from the venom of the formosan cobra (naja naja atra).	a cardiotoxin-like basic polypeptide, designated as clbp, was isolated from the venom of naja naja atra by gel filtration on sephadex g-50 followed by cm-cellulose chromatography. the cytotoxicity toward yoshida sarcoma cells and lethal toxicity toward mice of clbp were both one-order lower than those of cardiotoxins and cobrotoxin, respectively. clbp is a single polypeptide consisting of 61 amino acid residues with four intramolecular disulfide linkages. the amino acid sequence of clbp shows a ...	1985	4091854
methyl branching in short-chain lecithins: are both chains important for effective phospholipase a2 activity?	several seven-carbon fatty acyl lecithins with varied acyl chain branching have been synthesized and characterized as potential phospholipase a2 substrates. micellar bis(4,4-dimethylpentanoyl) phosphatidylcholine, bis(5-methylhexanoyl)phosphatidylcholine, bis(3-methylhexanoyl)phosphatidylcholine, and bis(2-methylhexanoyl)phosphatidylcholine are poor substrates for phospholipase a2 (naja naja naja). these branched lecithins also inhibit the hydrolysis of diheptanoylphosphatidylcholine by the enzy ...	1985	3986178
[biospecific adsorption chromatography of phospholipase a2 from different sources].	methods of biospecific adsorption chromatography of phospholipase a2 obtained from porcine pancreas and naja naja oxiana, vipera ursini renardi, vespa orientalis venoms were developed. granulated polyamide with covalently linked phosphatidylethanolamine were used as an affinity adsorbent. chemical inertness of linked phosphatidylethanolamine to the hydrolytic action of phospholipase a2 and its high affinity for biospecific complexes are shown. forms of phospholipase a2 different in their affinit ...	1985	3991479
cytolytic activity of cytotoxin isolated from indian cobra venom against experimental tumor cells.	cytolytic activity of cytotoxin isolated from the venom of the indian cobra (naja naja) on experimental tumor cells was far stronger than that on normal cells such as peritoneal exudate cells, spleen cells, and erythrocytes of the rat. the effect on yoshida sarcoma cells was temperature-dependent, being stronger at 37 degrees c than at 0 degrees c. intramolecular disulfide linkages and free amino groups in the cytotoxin molecule were shown to be essential for the lytic action on the cell membran ...	1985	4015662
activation, aggregation, and product inhibition of cobra venom phospholipase a2 and comparison with other phospholipases.	the kinetics of phospholipid hydrolysis by cobra venom phospholipase a2 were examined and compared to those of phospholipase a2 from porcine pancreas, crotalus adamanteus (rattlesnake) venom, and bee venom. only the enzyme from naja naja naja (cobra) venom was found to be activated significantly by phosphorylcholine-containing compounds when hydrolyzing phosphatidylethanolamine. the cobra venom enzyme was also the only one in which these activators induced protein aggregation. the parallel speci ...	1985	4030786
biochemical characterization of two nicotinic receptors from the optic lobe of the chick.	we have studied putative nicotinic acetylcholine receptors in the optic lobe of the newborn chick, using 125i-labeled alpha-bungarotoxin, a specific blocker of acetylcholine receptors in the neuromuscular junction, and [3h]acetylcholine, a ligand which in the presence of atropine selectively labels binding sites of nicotinic character in rat brain cortex (schwartz et al., 1982). [3h]acetylcholine binds reversibly to a single class of high affinity binding sites (kd = 2.2 x 10(-8) m) which occur ...	1985	4055785
contractile response of the isolated dorsal aorta of the snake to angiotensin ii and norepinephrine.	vasopressor action is a phylogenetically old function of angiotensin (ang) ii. the action can be ascribed to both direct activation of vascular ang ii receptors and through catecholamine release. in the rat snake, ptyas korros, the possible presence of common adrenergic-ang receptors and their involvement in this action have been proposed. in order to elucidate the vasopressor mechanism of ang ii in the snake, and to test the presence of common adrenergic-ang receptors, the contractile response ...	1985	4065534
effect of pure venom phospholipase a2 from the central asian cobra (naja naja oxiana eichwald) on oxidative functions of rat liver mitochondria.		1985	4077115
[central action of snake venoms on body temperature in rats].	experiments on rats were made to study the effect on the body temperature of the rat of intracerebroventricular injection of venoms of indian cobra, north american rattle snake, and central asian shchitomordnik. it was established that the rise of rectal temperature by 1.5-2.0 degrees c after 90 min was evoked by cobra venom alone. that increase in the body temperature was not prevented by pretreatment with the protein synthesis inhibitors anisomycin or cycloheximide, but was completely abolishe ...	1985	4085638
positional distribution of fatty acids in cardiolipin of mitochondria from 21-day-old rats.	pure cardiolipins (1,3-diphosphatidylglycerol) were prepared from mitochondria of heart, liver and kidney from 21-day-old male wistar rats and submitted to naja naja venom phospholipase a2 (ec 3.1.1.4) action. incubation conditions were controlled carefully, and a complete hydrolysis of cardiolipin to lysocardiolipin (di [1 (1'') acyl sn-glycero-3-phosphoryl] 1',3'-sn-glycerol) and fatty acids from positions 2(2'') was obtained in less than two hr practically without side reactions. cardiolipins ...	1985	4094521
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
[the detoxification of naja naja atra venom and preparation of potent antivenin].	the 99.2% toxicity of naja naja atra venom can be detoxified by treatment with 0.25% ga (glutaraldehyde) solution at ph 6.8 and still remains its antigenicity. using the ga treated venom incorporated with freund's complete adjuvant as immunogen, the titer of immune horse sera can be enhanced rapidly. the modified immunization method not only shortened the period of immunization (from 180 to 60 days), but also increased the potency of immune sera (from 75 to 170 units). the method also diminished ...	1985	3933920
aggregation studies on fluorescein-coupled cobra venom phospholipase a2.	phospholipase a2 from naja naja naja venom (indian cobra) undergoes a concentration-dependent aggregation, and at an assay concentration of 1 microgram ml-1, it exists as a monomer. however, there is some evidence that the enzyme is actually active as a dimer or higher order aggregate. previous attempts to determine the aggregation state of the enzyme under actual assay conditions were thwarted by experimental difficulties due in part to the low enzyme concentrations required. this aggregation h ...	1985	3936540
two new inhibitors of phospholipase a2 produced by penicillium chermesinum. taxonomy, fermentation, isolation, structure determination and biological properties.	plastatin and the known fungal metabolite, luteosporin, have been isolated from fermentations of penicillium chermesinum as inhibitors of porcine pancreatic phospholipase a2 (pla2). structure 1 for plastatin was deduced from its spectroscopic properties. plastatin and luteosporin inhibited pancreatic pla2 competitively with ki values of 0.89 microm and 12.8 microm, respectively. pla2 preparations from naja naja and crotalus adamanteus were not significantly inhibited by plastatin and luteosporin ...	1985	3839502
use of some snake venoms in the diagnostics of paroxysmal nocturnal hemoglobinuria (pnh).	the crude toxin of agkistrodon piscivorus was found to produce hemolysis of pnh erythrocytes by way of complement activation, however the degree of pnh blood cell lysis was lower than in other techniques used. the crude toxins of naja naja and naja oxiana cause much higher hemolysis though lower hemolysis takes place in normal blood cells. in some normal persons and different blood diseases it is responsible for high hemolysis even when the complement is absent. from naja naja toxin a fraction c ...	1985	2410338
[complement and noncomplement hemolysis of blood cells in patients with various blood diseases after the administration of the crude toxins of agkistrodon piscivorus, naja naja, naja oxiana].		1984	6515308
on the interaction of cobra venom protein cardiotoxins with erythrocytes.	the principally active hemolytic toxin (cardiotoxin) previously purified from the venom of the thailand cobra, naja naja siamensis, was shown to produce spontaneous twitching, contractures and membrane depolarization in sartorius muscles from the frog, rana pipiens. spontaneous twitching, observed at concentrations greater than 0.1 um was completely abolished by addition of tetrodotoxin and not affected by d-tubocurarine. dose and time dependent membrane depolarization of muscle fibers was obser ...	1984	6333874
variation in yield and lethality of venoms from iranian snakes.	the dangerous venomous terrestrial snakes of iran belong to three groups: the elapidae (cobras); the viperinae (true vipers); the crotalinae (pit vipers). geographical distribution of each species was determined. studies on the venoms extracted from the following iranian snakes, oxus cobra, naja naja oxiana, levantine viper (afyi), vipera lebetina, carpet viper, echis carinatus, persian horned viper, pseudocerastes persicus, latifii viper, vipera latifii, mountain viper, vipera xanthina and cauc ...	1984	6474490
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
higher-order structure in the 3'-terminal domain vi of the 23 s ribosomal rnas from escherichia coli and bacillus stearothermophilus.	an experimental approach was used to determine, and compare, the higher-order structure within domain vi of the 23 s ribosomal rnas from escherichia coli and bacillus stearothermophilus. this domain, which encompasses approximately 300 nucleotides at the 3' end of the rnas, consists of two large subdomains. the 5' subdomain has been conserved during evolution and appears to be functionally important for the binding of the ef-1 x gtp x aminoacyl-trna complex in eukaryotes. the 3' subdomain has di ...	1984	6209406
anaerobic metabolism of carbon tetrachloride and formation of catabolically resistant phospholipids.	anaerobic incubation of microsomes with 14c-carbon tetrachloride leads to trichloromethyl radicals which, apart from other detrimental reactions, bind covalently to phospholipids. these labelled lipids are extracted, phosphatidylcholine is isolated and incubated with phospholipase a2 from naja naja snake venom and from porcine pancreas. half of the covalently modified phosphatidylcholine is resistant toward phospholipase a2. distribution of such catabolically resistant phospholipids from the end ...	1984	6231931
properties of curaremimetic neurotoxin binding sites in the rat central nervous system.	properties of mammalian central nervous system binding sites for curaremimetic neurotoxins are investigated with the simonsen-albino rat and 125i-labeled alpha-bungarotoxin or the principal neurotoxin from naja naja siamensis. evidence is presented that high-affinity toxin binding sites are distributed as expected for a synaptic neurotransmitter receptor, display distinct nicotinic cholinergic pharmacology, and are sensitive to preincubation with nicotinic agonists. affinity of toxin sites for a ...	1984	6231955
effects of chicken and mammalian gonadotropin-releasing hormones (gnrh) on in vivo pituitary gonadotropin release in amphibians and reptiles.	the ability of mammalian and chicken gonadotropin-releasing hormones (gnrh) and their agonistic analogs to stimulate in vivo gonadotropin release were tested in a frog (rana catesbeiana), snake (naja naja), and turtle (sternotherus odoratus). in the frog, chicken and mammalian gnrh were equipotent in stimulating the release of fsh and lh. attendant increases in plasma androgen and the occurrence of spermiation confirmed the release of biologically active gonadotropin. neither of the gnrh prepara ...	1984	6427062
effect of the purified phospholipases a2 from snake and bee venoms on rabbit platelet function.	effects of seven purified phospholipases a2 from the venoms of snakes (naja naja atra, trimeresurus mucrosquamatus and t. gramineus) and honey bee (apis mellifera) on rabbit washed platelet suspension in the absence of bovine serum albumin have been studied. only phospholipases a2 from n. n. atra, t. mucrosquamatus and a. mellifera venoms induced platelet aggregation with small amounts of 14c-serotonin release. they showed tachyphylaxis and also cross-tachyphylaxis in inducing platelet aggregati ...	1984	6441310
cardiotoxin from naja naja atra snake venom: a potentiator of platelet aggregation.	cardiotoxin, isolated from naja naja atra snake venom, potentiates platelet aggregation induced by adp, thrombin, collagen and venom phospholipase a2. the malondialdehyde formation caused by adp, thrombin and venom phospholipase a2 were also increased in the presence of cardiotoxin. both potentiation of aggregation and increase in malondialdehyde were blocked by indomethacin or ca2+ (5 mm or 0.05 mm). cardiotoxin did not potentiate thrombin-induced aggregation of p-bromophenacyl bromide-modified ...	1984	6474495
catabolism of phospholipids by chicken seminal components after storage.	the possibility of an activation of chicken spermatozoal phospholipase a2 during in vitro storage of undiluted semen was investigated. after storage for periods up to 24 hr at 5 c, the ability of semen to catabolize added phosphatidylcholine labeled on the 2nd carbon of glycerol with 14c oleic acid was assessed. neither spermatozoa nor plasma from undiluted chicken semen was found to be capable of catabolizing added 14c labeled phosphatidylcholine, regardless of the storage period. no enzyme act ...	1984	6483728
joint action of membrane-active components from central asian cobra (naja naja oxiana eichwald) venom on rat liver mitochondrial functions.		1984	6490077
clinical features of neurotoxic snake bite and response to antivenom in 47 children.	among 47 children admitted to the chulalongkorn medical school hospital for neurotoxic snake bite, the attackers were identified in 15; the cobra (naja naja) was the snake involved in all cases. clinical manifestations in all 47 children appeared to follow a similar pattern. drowsiness heralded the systemic effects in most of the patients. the characteristic systemic signs were those resulting from the neuromuscular effects of the venom and included ptosis, frothy saliva, slurred speech, respira ...	1984	6507733
evidence for a highly asymmetric arrangement of ether- and diacyl-phospholipid subclasses in the plasma membrane of krebs ii ascites cells.	(1) krebs ii ascites cells were taken as a model of the neoplastic cells to investigate the transverse distribution of phospholipids in the plasma membrane. the experimental procedure was based on non-lytic degradation of phospholipids in the intact cell by naja naja phospholipase a2 and staphylococcus aureus sphingomyelinase c and on phospholipid analysis of purified plasma membranes. it was shown that the three major phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine and sphing ...	1984	6509047
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
effect of ca2+ on the action of cobra (naja naja oxiana eichwald) venom components on mitochondrial enzyme systems.		1984	6526419
[a new low molecular-weight protein effector of human complement from the venom of the central asian cobra naja naja oxiana].	six protein effectors of human complement were isolated from the whole venom of the central asian cobra naja naja oxiana. three of them have acidic properties and molecular weights of 61 000, 5000 and 3000, and the rest are basic proteins with molecular weights of 54 000, 9000 and 7000. two low molecular weight basic proteins cfb-ii and cfb-iii are isolated in as high amounts as 115 and 85 mg per g of dry venom. all the effectors inhibit the classical pathway of complement activation and, with t ...	1984	6567467
stimulation of prostaglandin e2 synthesis by exogenous phospholipase a2 and c in rabbit kidney medulla slices.	we have investigated the effects of phospholipase a2 and c on the synthesis of prostaglandin e2 in rabbit kidney medulla and the release of fatty acids from the medulla slices. exogenous phospholipase a2 [from naja naja (indian cobra) venom] and phospholipase c (from clostridium welchii) stimulated prostaglandin e2 production in a dose-dependent manner. at the maximal effective concentrations (0.5 unit of phospholipase a2/ml, 2 units of phospholipase c/ml), phospholipase c increased prostaglandi ...	1984	6585201
complement in the serum and venom of brazilian snakes (crotalidae).	proteins antigenically related to cof, the anticomplementary protein of the venom of the indian hooded cobra (naja naja), were found in a variety of elapid and viper venoms but not in the venom of brazilian crotalids . in keeping with this finding was the weak ability of brazilian snake venom to convert c3 in human serum. all snake serums tested, including brazilian crotalids , contained a beta-globulin antigenically related to cof. this serum protein in brazilian snake serum had a number of cha ...	1984	6587747
phospholipid asymmetry in the membranes of intact human erythrocytes and in spectrin-free microvesicles derived from them.	phospholipase a2 from bee venom and naja naja has been used to study the orientation of phospholipids present in the membrane of intact human erythrocytes and in spectrin-free microvesicles derived from the cells by treatment with ca2+ and a23187. little difference between the cells and microvesicles was observed in the apparent accessibility of phospholipids to the enzyme, suggesting that the original lipid asymmetry was maintained in the absence of spectrin. however, incubation of the microves ...	1984	6722143
[a case of bite by naja naja naja in india. problems posed by the treatment of snake bites].	the author reports a case of poisonous snake bite by naja naja naja, in india. the patient recovered rapidly after treatment by antivenom serum. he emphasizes the importance of prompt intravenous injection of serum. serum is less active for viper bites, and should be injected even more rapidly. however, in france, some authors prefer heparin for treating french viper bites. further studies are needed to clarify this therapeutic problem.	1984	6722971
bindings of ca2+ and substrate analogs to a cobra venom phospholipase a2 in which the alpha-amino group is modified to an alpha-keto group.	the ph dependence of the chemical reaction rate of p-bromophenacyl bromide (bpb) with his 48 of cobra (naja naja atra) venom phospholipase a2, in which the alpha-nh2 group had been selectively modified to an alpha-keto group, was studied at 25 degrees c and ionic strength 0.1 in the absence of ca2+. the ph-dependence curve was monophasic with a midpoint at ph 7.9, which corresponds to the pk value of his 48 of the alpha-nh2-modified enzyme, whereas the curve for the intact enzyme was biphasic, i ...	1984	6530402
[fluorescence characteristics of lysine and arginine residues in venom of naja naja atra].		1984	6239506
inactivation of toxin b from the indian cobra by cleavage of a specific bond during limited hydrolysis with trypsin.	two neurotoxins, "toxin b", a long neurotoxin from naja naja, and "cobrotoxin", a short neurotoxin from naja naja atra, were compared with respect to their limited hydrolysis by trypsin and chymotrypsin and its effect on their neurotoxicity. limited hydrolysis of toxin b with trypsin cleaves peptide bonds at arg68-lys69 and arg33-gly34 in the toxin molecule and causes complete loss of the neurotoxicity yielding des-carboxyl terminal toxin b(1-68) nicked at arg33-gly34 in the molecule. on the oth ...	1984	6487344
cobra venom factor: improved method for purification and biochemical characterization.	a method to purify cobra venom factor (cvf) from cobra venom by sequential column chromatography is described which yields a product virtually free of phospholipase a2, a common contaminant of cvf preparations. the separation of phospholipase a2 from cvf was achieved by chromatography on cibacron blue-agarose, a resin that tightly binds cobra venom phospholipase a2. a rapid and simple hemolytic assay for the qualitative and quantitative determination of cvf based on its ability to induce bystand ...	1984	6491300
reoxidation and renaturation studies on the main toxin of naja naja samarensis.	the main toxin of naja naja samarensis is a very small and rigid protein (mr 6850, 8 cysteines). when fully reduced, it regains its native conformation by a mechanism involving a rapid cysteine oxidation and a slower, less temperature-dependent disulfide exchange. in a native-like form of the protein we observed a population whose cysteines were incompletely reoxidized. when intermediates with blocked cysteines were incubated with oxidized and reduced glutathione, the percentage of native-like m ...	1984	6500055
[2-d-nmr study of the conformation characteristics of toxin 3 from naja naja siamensis venom].	the spatial structure of "long" toxin 3 naja naja siamensis in solution has been studied by methods of two-dimensional (2d) 1h nmr spectroscopy. the individual signal assignments for 67 out of 71 residues and analysis of nuclear overhauser effects between distinct protons of the molecule allowed the comparison of the toxin 3 conformations at different ph values and temperatures. it was shown that the deprotonated imidazole ring of his22 residue (at ph greater than or equal to 7,5) is surrounded ...	1984	6529443
amino acid sequence of cytotoxin iia isolated from the venom of the indian cobra (naja naja).	a cytotoxic basic polypeptide, designated as cytotoxin iia, was purified to homogeneous state from the venom of the indian cobra (naja naja) by a combination of gel filtration on sephadex g-50, cm-cellulose chromatography, and fast protein liquid chromatography. cytotoxin iia is a single polypeptide consisting of 60 amino acid residues with four intramolecular disulfide linkages. the toxin showed high cytotoxicity toward yoshida sarcoma and ascites hepatoma cells as did cytotoxins i and ii isola ...	1984	6525197
[nmr study of the spatial structure of the naja naja siamensis toxin 3].	the 300 and 500 mhz 1h nmr spectra of a long-chain neurotoxin, toxin 3 naja naja siamensis (s-t3), its derivatives and close homolog, toxin 3 naja naja naja (n-t3), have been analyzed. a combination of double resonance, difference spectroscopy and usage of a series of toxin s-t3 derivatives acetylated or trifluoroacetylated at lysine residues allowed to assign the signals from all aromatic protons and a number of signals in the aliphatic region, and to elucidate the microenvironment of certain f ...	1984	6437411
fluorescence energy transfer between cobra alpha-toxin molecules bound to the acetylcholine receptor.	an approach was developed with steady state fluorescence energy transfer measurements to examine the spatial relationship between the two alpha-toxins bound to the acetylcholine receptor. by taking advantage of the slow dissociation rates of alpha-toxins (naja naja siamensis 3) from the receptor and of the equal probability with which alpha-toxins bind to the two alpha-toxin-binding sites, we derived an equation which allows prediction of a "true" efficiency of transfer based on the relationship ...	1984	6715368
effect of central asian cobra (naja naja oxiana eichwald) venom cytotoxin on enzymatic hydrolysis of phospholipids.		1984	6490078
[relative localization of the bound acetylcholine receptor subunits and neurotoxin].	a series of neurotoxin ii (naja naja oxiana) derivatives, each containing one p-azido-[14c]benzoyl group, have been prepared. those labeled at leu1, lys15, lys25, lys26, or lys46 associate specifically with the acetylcholine receptor from the torpedo marmorata electric organs and form the crosslinks with it as a result of irradiation. electrophoresis in polyacrylamide gel and gel chromatography revealed the contacts between the neurotoxins and alpha, beta, gamma and delta subunits of the recepto ...	1984	6487390
a comparison of eel electroplax and snake venom acetylcholinesterase.	the effects of some cholinergic ligands, harmala alkaloids and local anesthetics on the activity of eel electroplax and naja naja siamensis venom acetylcholinesterase have been studied. in most cases, eel electroplax was found to be more susceptible towards inhibition than the venom acetylcholinesterase. no major difference was observed with respect to the type of inhibition in both enzymes. the activation of the two enzyme preparations by inorganic cations (ca2+, mg2+ and na+) showed a similar ...	1984	6146473
photochemically induced nuclear polarization study of exposed tyrosines, tryptophans, and histidines in postsynaptic neurotoxins and in membranotoxins of elapid and hydrophid snake venoms.	the accessibility of surface tyrosines, histidines, and tryptophans in snake venom neurotoxins (short and long) and in membranotoxins to excited triplet 10-(carboxyethyl)-flavin was studied by photochemically induced dynamic nuclear polarization at 270 mhz. trp-29 is accessible in the short neurotoxins--erabutoxins a, b, and c and cobrotoxin--and also in the long neurotoxins--alpha-cobratoxin and alpha-bungarotoxin. tyr-25 is practically inaccessible in all neurotoxins. tyr-39 in cobrotoxin and ...	1984	6498168
purification of acidic phospholipases from indian cobra (naja naja naja) venom.		1983	6668341
chiral synthesis of a dithiolester analog of phosphatidylcholine as a substrate for the assay of phospholipase a2.	the synthesis of a dithiolester analog of phosphatidylcholine, 1,2-bis(heptanoylthio)-1,2-dideoxy-sn-glycerol-3-phosphocholine (thio pc), is described. starting with 1-trityl-sn-glycerol (prepared from d-mannitol), tosylation followed by displacement with potassium methyl xanthate gave a trithiocarbonate. reductive cleavage of the latter gave a 1,2-dithiol which was then acylated, detritylated, and esterified with choline phosphate. hydrolysis of thio pc by phospholipase a2 (naja naja) indicated ...	1983	6655369
[study of long-chain neurotoxins from naja naja siamensis and naja naja oxiana venoms by circular dichroism and fluorescence].	cd and fluorescence spectroscopy were used to study the conformational mobility of long-chain neurotoxins from the venom of cobra naja naja siamensis and naja naja oxiana (stx and nt-i, respectively). microenvironment of tryptophan residues in these neurotoxins and their lysine-modified derivatives was also analyzed. ionization of his22 (pk 5,4-5,6) in stx influences the invariant trp29 microenvironment. no conformational change was observed on titration of single his residue situated in the c-t ...	1983	6679782
the interaction of dialkyl ether lecithins with phospholipase a2 (naja naja naja).	dialkyl lecithins are nonhydrolyzable substrate analogues for phospholipase a2 (naja naja naja). short chain dialkyl lecithins (which form monomers and micelles), and long chain ether-linked lecithins (which form bilayers or can be solubilized in detergent micelles) have been used to study phospholipase a2/phospholipid interactions. the results of gel filtration, 1h and 31p nmr spectroscopy, kinetic assays and uv difference spectroscopy show that binding of the ether-linked lecithins is independ ...	1983	6687887
[high-performance exclusion liquid chromatography of protected peptides on soft and semi-solid gels].	fractionated soft gels sephadex lh-20, sephadex lh-60, enzakryl k-2 and semirigid gels - spheron p-40, spheron p-300 and spheron p-1000 were tested for separation of protected synthetic fragments of neurotoxin ii from the central asian cobra (naja naja oxiana) venom. applicability of the above gels for size exclusion hplc of protected peptides in organic media is discussed.	1983	6679779
[preparation and esr study of spin-labeled derivatives of naja naja oxiana neurotoxin ii].	after neurotoxin ii naja naja oxiana reaction with n-hydroxysuccinimidyl 2,2,6,6-tetramethyl-4-carboxymethylpiperidine-1-oxyl, six derivatives were isolated, each containing one spin label. their analysis (reduction, carboxymethylation, tryptic hydrolysis, isolation and identification of the spin labeled peptide) allowed to localize the label position: the epsilon-amino groups of lys15, lys25, lys26, lys44, lys48, and alpha-amino group of leu1. the neurotoxin ii reaction with n-hydroxysuccinimid ...	1983	6091692
ultracytochemical observations on intracytoplasmic lipids by enzymic digestive methods: histochemical trials1.	the penetration of rbizopus arrhizus lipase into ethioine fatty livers was examined histochemically. a free-floating, 30 μm thick vibratome section of the livers perfused with aldehydes was shown to be suitable for ultracytochemical analysis by the lipase digestive method. accessibility of phospholipids in the outer membrane of erythrocytes to naja naja phospholipase a2was observed under a light microscope, and intact red cells were used for the ultracytochemical analysis by the phospholipase di ...	1983	28054839
an attempt to identify amino groups of naja naja siamensis neurotoxin that interact with acetylcholine receptor by a comparison of their reactivities in free and receptor-bound neurotoxin.	an attempt to identify amino groups of naja naja siamensis neurotoxin that interact with acetylcholine receptor by a comparison of their reactivities in free and receptor bound neurotoxin. toxicon 21, 219-229, 1983--free naja naja siamensis neurotoxin was acetylated with non-radioactive and acetylcholine receptor-bound neurotoxin with radioactive acetic anhydride. the toxins from the two experiments were combined and the monoacetyl derivatives isolated by chromatography on bio-rex 70. the yields ...	1983	6857707
[1h-nmr study of the naja naja oxiana neurotoxin ii and its spin-labeled derivatives. conformation of "short" neurotoxins].	in 1h nmr spectra of neurotoxin ii n. n. oxiana the chemical shift ph-dependences in h2o and 2h2o solutions were studied, and also the deuterium exchange rates and chemical shift temperature gradients were measured for the amide protons. the spin probe method was applied to assess the degree of exposure into solvent of the amide and side chain protons. with the purpose of establishing mutual disposition of certain neurotoxin ii groupings, nuclear overhauser effect was studied in the 1h nmr spect ...	1983	6679788
separation of cardiotoxins (cytotoxins) from the venoms of naja naja and naja naja atra by reversed-phase high-performance liquid chromatography.		1983	6668340
unfolding processes of small globular proteins: the two-state vs multi-state model.	1. the alcohol-induced unfolding of two homologous proteins, neurotoxin and cardiotoxin from taiwan cobra (naja naja atra) venom has been analysed. 2. it is postulated that the unfolding process for both proteins is a multi-state conformational transition. 3. it has been hypothesized that between the compact native state of the protein and its fully unfolded state there exists a quasi-continuous spectrum of conformational metastates of protein species. 4. the population distribution of these met ...	1983	6862085
induction of ornithine decarboxylase by treatment of guinea pig lymphocytes with phospholipase c.	treatment of guinea pig lymphocytes with clostridium perfringens phospholipase c but not with naja naja snake venom phospholipase a2 increased ornithine decarboxylase activity. the increase in ornithine decarboxylase activity was suppressed by actinomycin d or cycloheximide, suggesting that de novo syntheses of rna and protein are necessary for the increase in the enzyme activity. these results suggest that the activation of phospholipase c rather than that of phospholipase a2 is responsible for ...	1983	6299785
changes in membrane phospholipid distribution during platelet activation.	exposure of phospholipids at the outer surface of activated and control platelets was studied by incubation with a mixture of phospholipase a2 from naja naja and bee venom, solely or in combination with sphingomyelinase from staphylococcus aureus, using conditions under which cell lysis remained below 10%. incubation with phospholipase a2 alone revealed a markedly increased susceptibility of the phospholipids in platelets activated by a mixture of collagen plus thrombin, by the sh-oxidizing comp ...	1983	6418205
effects of intraventricular curarimimetics on hippocampal electrical activity.	the effects on the hippocampal electroencephalogram (eeg) of intraventricular injections of the nicotinic ligand alpha-naja naja toxin, and of d-tubocurarine, were studied in rats immobilized with gallamine or anesthetized with urethane. the eeg recordings were taped and processed off-line to calculate power spectra, autocorrelation functions, and averages. in addition, the times at which spike-and-wave complexes appeared were identified and autocorrelation histograms and cross correlations (wit ...	1983	6822252
ultracytochemical observations on intracytoplasmic lipids by enzymic digestive methods: histochemical trials.	the penetration of rhizopus arrhizus lipase into ethionine fatty livers was examined histochemically. a free-floating, 30 microns thick vibratome section of the livers perfused with aldehydes was shown to be suitable for ultracytochemical analysis by the lipase digestive method. accessibility of phospholipids in the outer membrane of erythrocytes to naja naja phospholipase a2 was observed under a light microscope, and intact red cells were used for the ultracytochemical analysis by the phospholi ...	1983	6827071
effect of phospholipase a on actions of cobra venom cardiotoxins on erythrocytes and skeletal muscle.	the actions of two phospholipase-free cardiotoxins from the venom of the cobra naja naja siamensis were compared to phospholipase-contaminated cardiotoxins in terms of their ability to lyse human erythrocytes and to depolarize and contract skeletal muscle. the presence of 3-5% (w/w) phospholipase caused a 20-30-fold increase in the haemolytic activity of the two cardiotoxins, the pure cardiotoxins being virtually without haemolytic activity at 10(-7)-10(-6) m. phospholipase contamination did not ...	1983	6830777
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
improvement of malayan cobra (naja naja sputatrix) antivenin.	a low molecular weight toxic fraction was isolated from venom of the malayan cobra (naja naja sputatrix) by sephadex g-50 gel filtration chromatography. the fraction accounted for almost 100% of the venom lethality. antisera were prepared by immunizing rabbits with the low molecular weight toxic fraction, the glutaraldehyde-treated low molecular weight toxic fraction and the glutaraldehyde-treated, sea snake neurotoxin-enriched low molecular weight toxic fraction, respectively. only the serum of ...	1983	6845388
isolation and characterization of two toxins from the venom of the malayan cobra (naja naja sputatrix).	two principal toxins of the malayan cobra (naja naja sputatrix) venom have been purified to electrophoretic homogeneity by successive sp-sephadex c-25 ion exchange chromatography and sephadex g-50 gel filtration chromatography. they are designated as sputa-neurotoxin 1 (sn1) and sputa-neurotoxin 2 (sn2), respectively. both toxins belong to the group of short neurotoxins which are composed of approximately 60 amino acid residues. the ld50 values following i.p. injection of the purified toxins are ...	1983	6857705
development of simple standard assay procedures for the characterization of snake venom.	in accordance with the recommendations of the report of a who coordination meeting on venoms and antivenoms, methods have been developed for the assessment of lethal, defibrinogenating, procoagulant, haemorrhagic, and necrotizing properties of venoms, and used to study 53 venoms from 30 different species of snakes of medical importance throughout the world. the venoms studied included echis carinatus (iran), naja naja kaouthia (thailand), notechis scutatus (australia), trimeresurus flavoviridis ...	1983	6609011
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
a double antibody sandwich micro-elisa kit for the rapid diagnosis of snake bite.	a micro elisa assay was established to diagnose systemic poisoning for the rapid administration of specific antivenom. rabbit anti venom igg was bound to the solid phase to enable detection of venom from both the malayan pit viper (agkistrodon rhodostoma) and the common cobra (naja naja). this assay is read visually and takes 35 to 45 minutes to perform. it can detect 15.6 ng/ml of viper venom in 75 minutes and 7.8 ng/ml of cobra venom in 55 minutes. tests on sera from snake bite patients showed ...	1983	6658505
inhibitory activity of cardiotoxin ii of the indian cobra & certain antibiotics on lysis of bacteria promoted by lysozyme.		1983	6671671
effect of membrane active components from the venom of central asian cobra (naja naja oxiana eichwald) on some functional parameters of mitochondria.		1983	6671676
phospholipids chiral at phosphorus. preparation and spectral properties of chiral thiophospholipids.	the thiophospholipid 1,2-dipalmitoyl-sn-glycero-3-thiophosphocholine (dppsc) was shown to be a mixture of two diastereomers by 31p nuclear magnetic resonance. the isomer that resonates at the lower field in cdcl3 (56.12 ppm) was designated as isomer a and the other (resonates at 56.07 ppm) as isomer b. phospholipase a2 from four different sources (bee venom, naja naja venom, crotalus adamanteus venom, and porcine pancreas) was shown to hydrolyze the isomer b of dppsc specifically, whereas phosph ...	1983	6688028
antigenic relationships between human and cobra complement factors c3 and cobra venom factor (cvf) from the indian cobra (naja naja).	the presence of a factor immunologically related to cobra venom factor (cvf) was demonstrated in serum and plasma from the indian cobra (naja naja kaoutia). the factor was purified from cobra plasma by affinity chromatography on an anti-cvf gel and was found to consist of a protein composed of two polypeptide chains similar in size to those of human c3. with use of immunoblotting technique, common antigenic determinants were found in the smaller chain of the prepared material and the beta-chain ...	1983	6194220
higher order structure in the 3'-minor domain of small subunit ribosomal rnas from a gram negative bacterium, a gram positive bacterium and a eukaryote.	an experimental approach was used to determine and compare the highest order structure within the 150 to 200 nucleotides at the 3'-ends of the rnas from the small ribosomal subunits of escherichia coli, bacillus stearothermophilus and saccharomyces cerevisiae. chemical reagents were employed to establish the degree of stacking and/or accessibility of each adenosine, guanosine and cytidine. the double helices were probed with a cobra venom ribonuclease from naja naja oxiana, and the relatively un ...	1983	6194304
hypotensive actions of snake parathyroid glands.	parathyroid gland extracts from four different snake species, ptyas korros, ptyas mucosa, elaphe radiata, and naja naja, were prepared and their hypotensive actions were assayed in anesthetized p. korros. all extracts were hypotensive and the responses, except that of n. naja, were dose related. their potencies were, however, different in different species. these data suggest that the hypotensive property of the parathyroid hormone is probably widely distributed in submammalian vertebrates.	1983	6667839
proteolytic-independent cobra neurotoxin inhibiting activity of curcuma sp. (zingiberaceae).	the 1: 1 (w/v) aqueous extract of curcuma sp. (zingiberaceae) was shown to antagonize the toxic action of naja naja siamensis neurotoxin possibly via direct inactivation of the toxin. the plant extract possessed proteolytic activity which could be separated from the neurotoxin inhibiting activity. the mechanism of antagonism between the plant extract and the neurotoxin was shown not to be involved with the existence of proteolytic activity in the plant extract.	1983	6356379
isolation and preliminary characterisation of two toxic phospholipases a2 from the venom of the malayan cobra (naja naja sputatrix).	two toxic phospholipases a have been isolated from the venom of the malayan cobra (naja naja sputatrix). the phospholipases a were purified by successive ion-exchange chromatography on sp-sephadex c-25, sephadex g-75 gel filtration chromatography and successive bio-rex 70 ion-exchange chromatography. the purified toxic phospholipases a were homogeneous electrophoretically. they were designated as sputatrix phospholipase a-i and sputatrix phospholipase a-ii. positional specificity studies showed ...	1982	7150663
effects of beta-bungarotoxin and phospholipase a2 from naja naja atra snake venom on atpase activities of synaptic membranes from rat cerebral cortex.	non-neurotoxic phospholipase a2 of formosan cobra venom possessed higher hydrolytic activity on phosphatidylcholine vesicles and also had higher inhibitory action on na+-k+-atpase and mg2+-atpase of the rat synaptic membrane than neurotoxic beta-bungarotoxin of formosan krait venom. na+-k+-atpase was more susceptible than mg2+-atpase to the inhibitory action of toxins, especially in the presence of triton x-100. the inhibition of atpases by toxins followed the michaelis-menton equation. it is in ...	1982	6123164
effects of iodipamide on human c3 and factor b in vitro.	the effects of iodipamide on c3 and factor b in normal human serum and in purified form have been examined by immunoelectrophoresis and sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page). temperature-dependent changes in immunoelectrophoretic profiles have been observed; however, these are not the same as those obtained after treatment of normal human serum (nhs) with cobra venom factor naja naja. analyses of iodipamide-treated nhs and purified c3 and factor b by reducing sds-p ...	1982	6922882
inactivation and solubilization of opiate receptors by phospholipases a2.	(1) as previously shown, stereospecific binding of opiates to membrane bound receptors is inhibited by treatment with small amounts of phospholipase a2 from vipera russelli. this effect is quantified and compared with the enzymes from the venoms of naja naja siamensis, apis mellifica and from porcine pancreas. all enzymes are equally effective. the inhibition is due to partial phospholipid hydrolysis leading to inactivation of membrane-bound receptor. (2) bee venom phospholipase a2 together with ...	1982	6279149
purification and partial characterization of a bacterial phospholipid: cholesterol acyltransferase.	a glycerophospholipid:cholesterol acyltransferase has been purified to near homogeneity from cell-free culture supernatants of aeromonas salmonicida. the characteristics of the enzyme distinguish it from bacterial phospholipases; however, it shares several properties with the lecithin:cholesterol acyltransferase of mammalian plasma. thus, the enzyme inhibits 2-positional specificity as an acyltransferase and it will act as a phospholipase a2 in the absence of cholesterol. furthermore, it has no ...	1982	7061477
some parameters of affinity chromatography in the purification of antibody against naja naja siamensis toxin 3.	some parameters in the purification of antibodies against naja naja siamensis toxin 3 by affinity chromatography were studied on toxin sepharose, toxin-succinylaminoethyl sepharose, toxin-albumin sepharose and toxin succinylaminoethyl biogel adsorbents. immunologically pure antibody with 10-12-fold increase in potency was obtained by chromatography of horse refined globulin on all these adsorbents. the maximum antibody binding capacities were higher for adsorbents containing linear spacers but r ...	1982	7061874
the trna-like structure at the 3' terminus of turnip yellow mosaic virus rna. differences and similarities with canonical trna.	the 3' terminus of tymv rna, which possesses trna-like properties, has been studied. a 3' terminal fragment of 112 nucleotides was obtained by cleavage with rnase h after hybridization of a synthetic oligodeoxynucleotide to the viral rna. the accessibility of cytidine and adenosine residues was probed with chemical modification. enzymatic digestion studies were performed with rnase t1, nuclease s1 and the double-strand specific rnase from the venom of the cobra naja naja oxiana. a model is propo ...	1982	7079175
biochemical and pharmacological properties of cardiotoxins isolated from cobra venom.	it has been established that cardiotoxins isolated from elapidae snakes tend to be contaminated with phospholipase. after a thorough comparison of the methods available for the separation of these two components, both hydrophobic and immunoaffinity chromatography have been found to be convenient and effective methods. with cardiotoxins isolated from naja naja siamensis we observed that as the contaminating phospholipase was removed, the cardiotoxins were converted from relatively powerful haemol ...	1982	7080031