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Nunes KP, Costa-Gonçalves A, Lanza LF, Cortes SF, Cordeiro MN, Richardson M, Pimenta AMC, Webb RC, Leite R, De Lima ME. Tx2-6 toxin of the Phoneutria nigriventer spider potentiates rat erectile function. Toxicon 2008; 51:1197-206. [PMID: 18397797 DOI: 10.1016/j.toxicon.2008.02.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 02/07/2008] [Accepted: 02/08/2008] [Indexed: 11/26/2022]
Abstract
The venom of the spider Phoneutria nigriventer contains several toxins that have bioactivity in mammals and insects. Accidents involving humans are characterized by various symptoms including penile erection. Here we investigated the action of Tx2-6, a toxin purified from the P. nigriventer spider venom that causes priapism in rats and mice. Erectile function was evaluated through changes in intracavernosal pressure/mean arterial pressure ratio (ICP/MAP) during electrical stimulation of the major pelvic ganglion (MPG) of normotensive and deoxycorticosterone-acetate (DOCA)-salt hypertensive rats. Nitric oxide (NO) release was detected in cavernosum slices with fluorescent dye (DAF-FM) and confocal microscopy. The effect of Tx2-6 was also characterized after intracavernosal injection of a non-selective nitric oxide synthase (NOS) inhibitor, L-NAME. Subcutaneous or intravenous injection of Tx2-6 potentiated the elevation of ICP/MAP induced by ganglionic stimulation. L-NAME inhibited penile erection and treatment with Tx2-6 was unable to reverse this inhibition. Tx2-6 treatment induced a significant increase of NO release in cavernosum tissue. Attenuated erectile function of DOCA-salt hypertensive rats was fully restored after toxin injection. Tx2-6 enhanced erectile function in normotensive and DOCA-salt hypertensive rats, via the NO pathway. Our studies suggest that Tx2-6 could be important for development of new pharmacological agents for treatment of erectile dysfunction.
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Affiliation(s)
- K P Nunes
- Departamento de Fisiologia e Biofisica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais , Belo Horizonte, Minas Gerais, Brazil
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2
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De Lima ME, Figueiredo SG, Pimenta AMC, Santos DM, Borges MH, Cordeiro MN, Richardson M, Oliveira LC, Stankiewicz M, Pelhate M. Peptides of arachnid venoms with insecticidal activity targeting sodium channels. Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:264-279. [PMID: 17218159 DOI: 10.1016/j.cbpc.2006.10.010] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 10/19/2006] [Accepted: 10/21/2006] [Indexed: 12/18/2022]
Abstract
Arachnids have a venom apparatus and secrete a complex chemical mixture of low molecular mass organic molecules, enzymes and polypeptide neurotoxins designed to paralyze or kill their prey. Most of these toxins are specific for membrane voltage-gated sodium channels, although some may also target calcium or potassium channels and other membrane receptors. Scorpions and spiders have provided the greatest number of the neurotoxins studied so far, for which, a good number of primary and 3D structures have been obtained. Structural features, comprising a folding that determines a similar spatial distribution of charged and hydrophobic side chains of specific amino acids, are strikingly common among the toxins from spider and scorpion venoms. Such similarities are, in turn, the key feature to target and bind these proteins to ionic channels. The search for new insecticidal compounds, as well as the study of their modes of action, constitutes a current approach to rationally design novel insecticides. This goal tends to be more relevant if the resistance to the conventional chemical products is considered. A promising alternative seems to be the biotechnological approach using toxin-expressing recombinant baculovirus. Spider and scorpion toxins having insecticidal activity are reviewed here considering their structures, toxicities and action mechanisms in sodium channels of excitable membranes.
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Affiliation(s)
- M E De Lima
- Lab. Venenos e Toxinas Animais, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil; Núcleo de Biomoléculas - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil.
| | - S G Figueiredo
- Centro de Ciências Fisiológicas, CBM - Universidade Federal do Espírito Santo, Vitória, ES, Brasil
| | - A M C Pimenta
- Lab. Venenos e Toxinas Animais, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil; Núcleo de Biomoléculas - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil
| | - D M Santos
- Lab. Venenos e Toxinas Animais, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil; Núcleo de Biomoléculas - Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil
| | - M H Borges
- Lab. Venenos e Toxinas Animais, Universidade Federal de Minas Gerais, 31.270-901, Belo Horizonte, MG, Brasil; Centro de Pesquisa Prof. Carlos R. Diniz, Fundação Ezequiel Dias, Belo Horizonte, MG, Brasil
| | - M N Cordeiro
- Centro de Pesquisa Prof. Carlos R. Diniz, Fundação Ezequiel Dias, Belo Horizonte, MG, Brasil
| | - M Richardson
- Centro de Pesquisa Prof. Carlos R. Diniz, Fundação Ezequiel Dias, Belo Horizonte, MG, Brasil
| | - L C Oliveira
- Departamento de Farmácia Bioquímica - Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39100-000, Diamantina, MG, Brasil
| | - M Stankiewicz
- Laboratory of Biophysics - Institute of General and Molecular Biology, N. Copernicus University, 87-100, Torun, Poland
| | - M Pelhate
- Lab. Récepteurs et Canaux Ioniques Membranaires, Université d'Angers, 49045, Angers, France
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3
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Novais CM, Pujatti PB, Castro MAS, Soares MA, De Lima ME, Simal C, Gouv?a dos Santos R. 99mTc radiolabeling of crotoxin as a tool for biodistribution studies. J Radioanal Nucl Chem 2006. [DOI: 10.1007/s10967-006-0270-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Gouv?a dos Santos R, Soares MA, Cruz JS, Mafra R, Lomeo R, Cordeiro MN, Pimenta AM, De Lima ME. Tx1, from Phoneutria nigriventer spidervenom, interacts with dihydropyridine sensitive-calcium channels in GH3 cells. J Radioanal Nucl Chem 2006. [DOI: 10.1007/s10967-006-0269-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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5
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Raslan DS, Jamal CM, Duarte DS, Borges MH, De Lima ME. Anti-PLA2 action test of Casearia sylvestris Sw. Boll Chim Farm 2002; 141:457-60. [PMID: 12577517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
Casearia sylvestris (Flacourtiaceae) is a plant which grows in the wild. The crude extract and pure substances from this plant induced partial inhibition of the PLA: (phospholipase A2) activity of snake venoms and some purified toxins. C. sylvestris extract efficiently neutralized the hemorrhagic and myotoxic activities caused by crude venoms and toxins.
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Affiliation(s)
- D S Raslan
- Departamento de Bioquímica e Imunologia-ICB, Laboratório de Venenos e Toxinas Animais, Universidade Federal de Minas Gerais (UFMG), Brazil
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Almeida FM, Pimenta AMC, De Figueiredo SG, Santoro MM, Martin-Eauclaire MF, Diniz CR, De Lima ME. Enzymes with gelatinolytic activity can be found in Tityus bahiensis and Tityus serrulatus venoms. Toxicon 2002; 40:1041-5. [PMID: 12076659 DOI: 10.1016/s0041-0101(02)00084-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Enzymes with gelatinolytic activity were detected in Tityus bahiensis and Tityus serrulatus venom. Their activity was optimal at pH 8.0 in SDS-PAGE-gelatin. They were inhibited by PMSF but not by iodoacetamide, pepstatin or phenantrolin in the assay conditions used. This suggests that these enzymes are serine proteases. The presence of metal ions did not affect the proteolytic activity of these enzymes. Several possible functions may be envisaged for these enzymes: in tissue permeabilization, pancreatitis and toxin processing.
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Affiliation(s)
- F M Almeida
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antonio Carlos, 6627, 31270-901 Belo Horizonte, Brazil
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7
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Abstract
To determine whether [Ca(2+)](e) modulates glutamate re-uptake, we studied the uptake mechanism into rat cerebrocortical synaptosomes. The removal of extracellular Ca(2+) caused a negative modulation in the uptake mechanism. The calculated K(50) value was 0.185 +/- 0.019 mM (n = 4). The Michaelis-Menten data analysis indicate that absence of Ca(2+) diminished the V(max) kinetic parameter by about 60% without changing significantly the K(m) suggesting a non-competitive mechanism. We also tested the involvement of intracellular Ca(2+) in this phenomenon by trapping BAPTA into the synaptosomal vesicles to control the Ca(2+) concentration. Our results suggest that intracellular Ca(2+) changes have a less predominant role on the glutamate uptake than do extracellular Ca(2+). These findings argue in favor of an important role of extracellular [Ca(2+)] in maintaining the L-glutamate re-uptake mechanism in the mammalian central nervous system.
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Affiliation(s)
- R A Mafra
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos 6627, 31270-901, Belo Horizonte MG, Brazil
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Siqueira AM, Martins NF, De Lima ME, Diniz CR, Cartier A, Brown D, Maigret B. A proposed 3D structure for crotamine based on homology building, molecular simulations and circular dichroism. J Mol Graph Model 2002; 20:389-98. [PMID: 11887801 DOI: 10.1016/s1093-3263(01)00139-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Crotamine, isolated from the venom of the South American rattlesnake Crotalus durissus terrificus is a strongly basic 42-amino acid polypeptide belonging to the small basic myotoxin family. As no tridimensional structure is available for this myotoxin subfamily, despite its important pharmacological interest, we propose in this paper a theoretical 3D model for crotamine. Starting from a homology modelling procedure, followed by intensive molecular dynamics (MD) simulations in water and complementary CD experiments, the designed 3D model is the first example of a tridimensional structure in this family of small basic myotoxins. Crotamine, therefore, belongs to a newly identified structural family presenting a common fold also found in beta-defensin and antopleurine-B. The proposed 3D model will be used for future calculations about crotamine aggregation and interaction with membranes.
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Affiliation(s)
- A M Siqueira
- Department of Biochemistry and Immunology, Federal University of Minas Gerais, Belo Horizonte, Brazil
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Pimenta AM, Martin-Eauclaire M, Rochat H, Figueiredo SG, Kalapothakis E, Afonso LC, De Lima ME. Purification, amino-acid sequence and partial characterization of two toxins with anti-insect activity from the venom of the South American scorpion Tityus bahiensis (Buthidae). Toxicon 2001; 39:1009-19. [PMID: 11223090 DOI: 10.1016/s0041-0101(00)00240-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We report here the isolation by a two-step chromatographic procedure of two new toxins from the South American scorpion Tityus bahiensis. Their amino-acid sequences and some of their biological features were established. The two toxins have different biological properties. Toxin TbIT-I had almost no activity or pharmacological effects in vertebrate tissues whereas it was lethal to house flies (LD50 80.0 ng/house fly). In contrast, Tb2-II was active against both mammals (intracerebroventricular injection of 100 ng/mouse was lethal) and insects (LD50 40.0 ng/house fly). The amino-acid sequences of these toxins were established and found to be similar (60-95%) to previously described beta-toxins from the Tityus genus. Based on the available comparative information, this study attempts identify possible structure-function relationships that may be responsible for the differences in bioactivity displayed by these toxins.
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Affiliation(s)
- A M Pimenta
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, 31270-901, MG, Belo Horizonte, Brazil.
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Kattah LS, Santoro MM, Diniz CR, De Lima ME. Crotoxin, the major toxin from the rattlesnake Crotalus durissus terrificus, inhibits 3H-choline uptake in guinea pig ileum. Braz J Med Biol Res 2000; 33:1093-7. [PMID: 10973144 DOI: 10.1590/s0100-879x2000000900017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We examined the effect of crotoxin, the neurotoxic complex from the venom of the South American rattlesnake Crotalus durissus terrificus, on the uptake of 3H-choline in minces of smooth muscle myenteric plexus from guinea pig ileum. In the concentration range used (0. 03-1 microM) and up to 10 min of treatment, crotoxin decreased 3H-choline uptake by 50-75% compared to control. This inhibition was time dependent and did not seem to be associated with the disruption of the neuronal membrane, because at least for the first 20 min of tissue exposure to the toxin (up to 1 microM) the levels of lactate dehydrogenase (LDH) released into the supernatant were similar to those of controls. Higher concentrations of crotoxin or more extensive incubation times with this toxin resulted in elevation of LDH activity detected in the assay supernatant. The inhibitory effect of crotoxin on 3H-choline uptake seems to be associated with its phospholipase activity since the equimolar substitution of Sr2+ for Ca2+ in the incubation medium or the modification of the toxin with p-bromophenacyl bromide substantially decreased this effect. Our results show that crotoxin inhibits 3H-choline uptake with high affinity (EC25 = 10 +/- 5 nM). We suggest that this inhibition could explain, at least in part, the blocking effect of crotoxin on neurotransmission.
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Affiliation(s)
- L S Kattah
- Laboratório de Venenos e Toxinas Animais, Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
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11
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Santos RG, Diniz CR, Cordeiro MN, De Lima ME. Binding sites and actions of Tx1, a neurotoxin from the venom of the spider Phoneutria nigriventer, in guinea pig ileum. Braz J Med Biol Res 1999; 32:1565-9. [PMID: 10585642 DOI: 10.1590/s0100-879x1999001200019] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Tx1, a neurotoxin isolated from the venom of the South American spider Phoneutria nigriventer, produces tail elevation, behavioral excitation and spastic paralysis of the hind limbs after intracerebroventricular injection in mice. Since Tx1 contracts isolated guinea pig ileum, we have investigated the effect of this toxin on acetylcholine release, as well as its binding to myenteric plexus-longitudinal muscle membranes from the guinea pig ileum. [125I]-Tx1 binds specifically and with high affinity (Kd = 0.36 +/- 0.02 nM) to a single, non-interacting (nH = 1.1), low capacity (Bmax 1.1 pmol/mg protein) binding site. In competition experiments using several compounds (including ion channel ligands), only PhTx2 and PhTx3 competed with [125I]-Tx1 for specific binding sites (K0.5 apparent = 7.50 x 10(-4) g/l and 1.85 x 10(-5) g/l, respectively). PhTx2 and PhTx3, fractions from P. nigriventer venom, contain toxins acting on sodium and calcium channels, respectively. However, the neurotoxin PhTx2-6, one of the isoforms found in the PhTx2 pool, did not affect [125I]-Tx1 binding. Tx1 reduced the [3H]-ACh release evoked by the PhTx2 pool by 33%, but did not affect basal or KCl-induced [3H]-ACh release. Based on these results, as well as on the homology of Tx1 with toxins acting on calcium channels (omega-Aga IA and IB) and its competition with [125I]-omega-Cono GVIA in the central nervous system, we suggest that the target site for Tx1 may be calcium channels.
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Affiliation(s)
- R G Santos
- Laboratório de Radiobiologia, Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, MG, Brasil
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12
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Mafra RA, Figueiredo SG, Diniz CR, Cordeiro MN, Cruz JD, De Lima ME. PhTx4, a new class of toxins from Phoneutria nigriventer spider venom, inhibits the glutamate uptake in rat brain synaptosomes. Brain Res 1999; 831:297-300. [PMID: 10412010 DOI: 10.1016/s0006-8993(99)01472-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We report the characterization of a new class of glutamate uptake inhibitors isolated from Phoneutria nigriventer venom. Glutamate transport activity was assayed in rat cerebrocortical synaptosomes by using [(3)H]-L-glutamate. PhTx4 inhibited glutamate uptake in a dose dependent manner. The IC(50) value obtained was 2.35+/-0.9 microg/ml which is in the observed range reported for glutamate uptake blockers. Tx4-7, one of PhTx4 toxins, showed the strongest inhibitory activity (50.3+/-0.69%, n=3).
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Affiliation(s)
- R A Mafra
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Av. Antônio Carlos, 6627, 31270-901, Belo Horizonte-MG, Brazil
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13
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De Lima ME, Martin-Eauclaire MF, Chavez-Olortegui C, Diniz CR, Granier C. Tityus serrulatus scorpion venom toxins display a complex pattern of antigenic reactivity. Toxicon 1993; 31:223-7. [PMID: 8456451 DOI: 10.1016/0041-0101(93)90290-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The antigenic properties of alpha-type and beta-type toxins purified from Tityus serrulatus (Ts) venom were analysed by radioimmunoassay, using rabbit antibodies raised against Ts VII, the main beta-type toxin in the venom, and against Ts IV, an alpha-type toxin. The anti-Ts VII serum did not recognize either the other beta-toxins Ts I and Ts II or the alpha-toxin Ts IV; the anti-Ts IV serum did not bind any of the three beta-toxins Ts I, Ts II or Ts VII. Thus, Tityus toxins display at least three distinct antigenic reactivity patterns.
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Affiliation(s)
- M E De Lima
- Departamento de Bioquimica e Immunologia, Instituto de Ciencias Biologicas, Belo Horizonte, M.G, Brazil
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14
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Céard B, De Lima ME, Bougis PE, Martin-Eauclaire MF. Purification of the main beta-toxin from Tityus serrulatus scorpion venom using high-performance liquid chromatography. Toxicon 1992; 30:105-10. [PMID: 1595074 DOI: 10.1016/0041-0101(92)90506-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The venom of the Brazilian scorpion Tityus serrulatus was fractionated using high-performance liquid chromatography which allowed us to purify in two steps the main beta-type toxin of the venom. The toxin constituted about 15% of the absorbance at 280 nm and 50% of the toxicity of the venom. According to its amino acid content, its electrophoretic migration on Phast-Gel homogenous 20 and its biological properties both in vivo by intracerebroventricular injection to the mouse (LD50 = 30 ng/kg mouse) and in vitro by competition receptor assay on rat brain synaptosomes (K0.5 = 80 pM), the toxin was identified as toxin Ts VII already purified from the same venom using low-pressure liquid chromatography (BECHIS et al., 1984 Biochem. biophys. Res. Commun. 122, 1146). The high-performance liquid chromatographic technique used improved by a factor of four the amount of toxin purified.
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Affiliation(s)
- B Céard
- Laboratoir de Biochimie, U.R.A. 1455 du C.N.R.S., Faculté de Médecine Secteur Nord, Marseille, France
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De Lima ME, Martin MF, Diniz CR, Rochat H. Tityus serrulatus toxin VII bears pharmacological properties of both beta-toxin and insect toxin from scorpion venoms. Biochem Biophys Res Commun 1986; 139:296-302. [PMID: 2429652 DOI: 10.1016/s0006-291x(86)80112-7] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Some beta-toxins from the South American scorpion Tityus serrulatus (e.g. Ts VII) are highly toxic both for mouse and fly larva. Radioiodinated Ts VII and the insect toxin from the North African scorpion Androctonus australis Hector (AaH IT) bind to the same site on a house fly head synaptosomal fraction. These results reinforce the hypothesis about the existence of a correlated series of scorpion toxins as previously defined by amino acid compositions and sequences, and immunological and circular dichroism studies, in suggesting that Ts VII constitutes a link which may fill the pharmacological gap existing between beta-toxins and insect toxins such as AaH IT.
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