RESUMEN
A clinical and epidemiological study of 267 cases of envenomation by Loxosceles spp. (loxoscelism), notified to Centro de Informações Toxicológicas de Florianópolis (Santa Catarina State, Brazil), was conducted between January 1985 and December 1995. Most of the incidents occurred along the coast of the mid-southern region of the state, during the warmest months. L. laeta and L. intermedia were identified as the causative agents. Cutaneous loxoscelism was clinically diagnosed in 232 (86.9%) patients with local pain (86.5%), oedema (80.5%), hyperaemia (79.8%) and necrosis (56.9%). Cutaneous-visceral loxoscelism was detected in 35 patients (13.1%) with intravascular haemolysis, manifested by jaundice (68.6%), oliguria (45.7%), dark urine (28.6%), haemorrhage (25.7%), anuria (8.6%) and shock (2.9%), besides the cutaneous effects. Specific antivenom was given to 125 patients (46.8%) and only 8 (6.5%) had mild reactions. Acute renal failure was observed in 17 cases (6.4%); 4 patients (1.5%) died, all of whom were children under 14 years old.
Asunto(s)
Picaduras de Arañas/epidemiología , Venenos de Araña/envenenamiento , Lesión Renal Aguda/etiología , Adolescente , Adulto , Antivenenos/efectos adversos , Antivenenos/uso terapéutico , Vesícula/etiología , Brasil/epidemiología , Niño , Femenino , Humanos , Ictericia/etiología , Masculino , Estudios Retrospectivos , Úlcera/etiologíaRESUMEN
The biological activities of the venom of three species of spiders of the genus Loxosceles were studied (L. gaucho, L. laeta and L. intermedia). The dermonecrotic and lethal activities are shared by all three Loxosceles venoms. Only low levels of proteolytic, myotoxic and phospholipase A2 activities were demonstrable even when a large amount of venom was used. No direct hemolytic activity was detected. L. intermedia venom was the most lethal (LD50 0.48 mg/kg), the L. laeta venom was the least lethal (LD50 1.45 mg/kg) whereas L. gaucho venom showed an intermediate value (LD50 0.74 mg/kg). The anti-Loxosceles serum used (anti-arachnidic serum) was able to neutralize the most important activities (i.e., dermonecrotic and lethal activities) of the three venoms. SDS-PAGE and immunoblotting using the anti-arachnidic serum showed that almost all venom antigens were recognized by this antiserum. The possible mechanisms of action of the Loxosceles venom are discussed.
Asunto(s)
Venenos de Araña/toxicidad , Arañas , Animales , Sueros Inmunes/inmunología , Dosificación Letal Mediana , Ratones , Pruebas de Neutralización , Conejos , Venenos de Araña/análisis , Venenos de Araña/inmunologíaRESUMEN
The biological activities of the venom of three species of spiders of the genus Loxosceles were studied (L. gaucho, L. laeta and L. intermedia). The dermonecrotic and lethal activities are shared by all three Loxosceles venoms. Only low levels of proteolytic, myotoxic and phospholipase A2 activities were demonstrable even when a large amount of venom was used. No direct hemolytic activitiy was detected. L. intermedia venom was the most lethal (LD50 0.48 mg/kg), the L. laeta venom was the least lethal (LD50 1.45 mg/kg) whereas L. gaucho venom showed an intermediate value (LD50 0.74 mg/kg). The anti-Loxosceles serum used (anti-arachnidic serum) was able to neutralize the most important activities (i.e., dermonecrotic and lethal activities) of the three venoms. SDS-PAGE and immunoblotting using the anti-arachnidic serum showed that almost all venom antigens were recognized by this antiserum. The possible mechanisms of action of the Loxosceles venom are discussed.
Asunto(s)
Animales , Ratones , Conejos , Sueros Inmunes/metabolismo , Necrosis , Venenos de Araña/química , Arañas/patogenicidad , Dosificación Letal Mediana , Venenos de Araña/toxicidadRESUMEN
Loxosceles spider venom usually causes a typical dermonecrotic lesion in bitten patients, but it may also cause systemic effects that may be lethal. Gel filtration on Sephadex G-100 of Loxosceles gaucho, L. laeta, or L. intermedia spider venoms resulted in three fractions (A, containing higher molecular mass components. B containing intermediate molecular mass components, and C with lower molecular mass components). The dermonecrotic and lethal activities were detected exclusively in fraction A of all three species. Analysis by SDS-PAGE showed that the major protein contained in fraction A has molecular weight approximately 35 kDa in L. gaucho and L. intermedia, but 32 kDa in L. laeta venom. These toxins were isolated from venoms of L. gaucho, L. laeta, and L. intermedia by SDS-PAGE followed by blotting to PVDF membrane and sequencing. A database search showed a high level of identity between each toxin and a fragment of the L. reclusa (North American spider) toxin. A multiple sequence alignment of the Loxosceles toxins showed many common identical residues in their N-terminal sequences. Identities ranged from 50.0% (L. gaucho and L. reclusa) to 61.1% (L. intermedia and L. reclusa). The purified toxins were also submitted to capillary electrophoresis peptide mapping after in situ partial hydrolysis of the blotted samples. The results obtained suggest that L. intermedia protein is more similar to L. laeta toxin than L. gaucho toxin and revealed a smaller homology between L. intermedia and L. gaucho. Altogether these findings suggest that the toxins responsible for most important activities of venoms of Loxosceles species have a molecular mass of 32-35 kDa and are probably homologous proteins.
Asunto(s)
Hidrolasas Diéster Fosfóricas/química , Piel/efectos de los fármacos , Venenos de Araña/química , Toxinas Biológicas/farmacología , Secuencia de Aminoácidos , Animales , Cromatografía en Gel , Cromatografía Liquida , Bases de Datos Factuales , Dextranos/metabolismo , Electroforesis Capilar , Electroforesis en Gel de Poliacrilamida , Ratones , Datos de Secuencia Molecular , Mapeo Peptídico , Hidrolasas Diéster Fosfóricas/toxicidad , Alineación de Secuencia , Análisis de Secuencia , Venenos de Araña/toxicidad , Toxinas Biológicas/aislamiento & purificaciónRESUMEN
In this paper further information concerning the ecological and biogeographical aspects of scorpionism is presented. Some of the information already outlined in three previous publications (10,14,16) is assessed, and new data given concerning the pattern of distribution presented by Tityus serrulatus in Brazil. Some new ideas are also proposed regarding the possible evolutionary advantages and disadvantages of parthenogenesis versus sexuality in both the short-term and the long-term.
Asunto(s)
Animales , Brasil , Características de la Residencia , Ecología , Partenogénesis , Reproducción , Escorpiones , Picaduras de Arañas/epidemiologíaRESUMEN
Cutaneous inoculation of Loxosceles spp. spider venoms produces local necrosis, occasionally accompanied by systemic intravascular clotting and hemolysis. In this work, we analyzed the role of the C system on the lysis of human erythrocytes (Eh) induced by Loxosceles venoms in vitro. Eh were treated with whole venom of Loxosceles laeta, Loxosceles gaucho, or Loxosceles intermedia, or with purified venom proteins, and incubated with C-sufficient (Cs-NHS) or C9-depleted autologous (C9d-NHS) serum. Hemolysis was determined spectrophotometrically, and deposition of C components or removal of C regulatory proteins was analyzed by FACS. Eh suspensions exposed to venoms or to a purified 35-kDa protein from L. intermedia were lysed after incubation with Cs-NHS, but not with C9d-NHS. Lysis was blocked by heating the serum at 50 degrees C or Ca2+/Mg2+ chelation by EDTA, but not by Ca2+ chelation with EGTA. Deposition of C1, C2, C3, C4, C5, and factor B on the venom-treated Eh occurred during activation of autologous C. Regulatory proteins decay-accelerating factor (DAF) and CD59 were not altered significantly. Conversion of C-resistant Eh into C-susceptible Eh by the L. intermedia venom was accompanied by incorporation of a 35-kDa venom protein onto the cell surface. Thirty-five-kilodalton-related proteins were detected in the two other Loxosceles venoms by ELISA, using rabbit antiserum against the L. intermedia 35-kDa protein. These data suggest that the C system mediates the lysis of human erythrocytes and, by extension, of other cell types able to incorporate the lytic factor of Loxosceles venoms on their cell surfaces.
Asunto(s)
Vía Alternativa del Complemento/efectos de los fármacos , Eritrocitos/inmunología , Venenos de Araña/sangre , Venenos de Araña/farmacología , Animales , Antígenos CD55/sangre , Fraccionamiento Químico , Cromatografía en Gel , Eritrocitos/química , Eritrocitos/efectos de los fármacos , Proteínas Hemolisinas/aislamiento & purificación , Proteínas Hemolisinas/farmacología , Hemólisis/efectos de los fármacos , Hemólisis/inmunología , Humanos , Proteínas de la Membrana/sangre , Proteínas de la Membrana/farmacología , Peso Molecular , ConejosRESUMEN
The venoms of seven species of scorpions living in different regions of Brazil were analysed with regard to their lethality, antigenic cross-reactivity and ability to induce antibody production. In mice, the tested scorpion venoms can be grouped as: (a) highly toxic: Tityus stigmurus Thorell (LD50 = 0.773 mg/kg), Tityus bahiensis (Perty) (LD50 = 1.062 mg/kg), Tityus serrulatus Lutz and Mello (LD50 = 1.160 mg/kg), and Tityus costatus (Karsch) (LD50 = 1.590 mg/kg); (b) moderately toxic: Tityus cambridgei Pocock (LD50 = 12.136 mg/kg); and (c) practically nontoxic: Rhopalurus agamemnon (Koch) (LD50 = 36.363 mg/kg), and Brotheas amazonicus Lourenço (LD50 = 90.909 mg/kg). On electrophoresis the venoms showed many protein bands displayed along the chromatogram, most of them cross-reacting in immunoelectrophoresis and immunoblotting using horse anti-T. serrulatus, anti-T. bahiensis or anti-T. serrulatus+T. bahiensis sera as probes. The antibodies present in these antivenoms combine with venom components as measured in vitro by the ELISA assay, and neutralize their lethal effects in vivo. These results indicate that horse anti-venoms against a mixture of T. serrulatus and T. bahiensis venoms or only against T. serrulatus venom yield an antibody population able to neutralize the toxic effects found in all venoms studied.
Asunto(s)
Antígenos/inmunología , Venenos de Escorpión/inmunología , Animales , Formación de Anticuerpos/inmunología , Western Blotting , Brasil , Reacciones Cruzadas , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Cobayas , Caballos , Sueros Inmunes/inmunología , Inmunoelectroforesis , Técnicas In Vitro , Inyecciones Intraperitoneales , Ratones , Proteínas/análisis , Venenos de Escorpión/administración & dosificación , Venenos de Escorpión/química , Venenos de Escorpión/toxicidad , EscorpionesRESUMEN
The venoms of seven species of scorpions living in different regions of Brazil were analysed with regard to their lethality, antigenic cross-reactivity and ability to induce antibody production. In mice, the tested scorpion venoms can be grouped as: (a) highly toxic: Tityus stigmurus Thorell (), Tityus bahiensis (Perty) , Tityus serrulatus Lutz and Mello (, and Tityus costatus (Karsch) ; (b) moderately toxic: Tityus cambridgei Pocock ; and (c) practically nontoxic: Rhopalurus agamemnon (Koch) , and Brotheas amazonicus Lourenço . On electrophoresis the venoms showed many protein bands displayed along the chromatogram, most of them cross-reacting in immunoelectrophoresis and immunoblotting using horse anti-T. serrulatus, anti-T. bahiensis or anti-T. serrulatus + T. bahiensis sera as probes. The antibodies present in these antivenoms combine with venom components as measured in vitro by the ELISA assay, and neutralize their lethal effects in vivo. These results indicate that horse antivenoms against a mixture of T. serrulatus and T. bahiensis venoms or only against T. serrulatus venom yield an antibody population able to neutralize the toxic effects found in all venoms studied.
Asunto(s)
Animales , Cobayas , Ratones , Antígenos/inmunología , Escorpiones , Escorpiones/inmunología , Sueros Inmunes/inmunología , Venenos de Escorpión/administración & dosificación , Venenos de Escorpión/inmunología , Venenos de Escorpión/química , Venenos de Escorpión/toxicidad , Antivenenos/química , Antivenenos/toxicidad , Brasil , Inmunoelectroforesis , Inyecciones Intraperitoneales , Proteínas/análisisRESUMEN
Injection of L. gaucho venom and antigens (ovalbumin, ovomucoid and bovine gamma globulin) into rabbit skin induced an intense local inflammatory lesion and resulted in a significant increase in the level of IgG antibodies to the antigen in both the primary and secondary humoral immune response. The adjuvant activity of the venom was associated with its high mol. wt components, which are responsible for the inflammatory lesion. Rabbits rendered unresponsive to the venom and injected with venom plus antigen presented a very mild local inflammatory reaction and no increase in antibody formation. When venom and antigen were injected simultaneously but at different skin sites no adjuvant effect was induced. However, when antigen was injected 4 hr after venom injection but at the same skin site a significant adjuvant effect was produced. Furthermore, when venom plus antigen was injected intradermally into mice, a species in which the venom does not cause an inflammatory skin lesion, no adjuvant effect was detected. It is suggested that the adjuvant effect of L. gaucho venom in rabbits is probably due to its ability to cause a local severe inflammatory reaction.
Asunto(s)
Adyuvantes Inmunológicos/farmacología , Hidrolasas Diéster Fosfóricas/farmacología , Venenos de Araña/farmacología , Animales , Ratones , Ratones Endogámicos BALB C , Ovalbúmina/inmunología , Ovomucina/inmunología , Hidrolasas Diéster Fosfóricas/inmunología , Conejos , Venenos de Araña/inmunología , gammaglobulinas/inmunologíaRESUMEN
Antigenic cross-reactivity between the components of venoms from three spiders of the genus Loxosceles, L. gaucho, L. laeta and L. intermedia, was studied. Species-specific antisera were prepared by immunization of rabbits with each venom. Anti-L. gaucho horse hyperimmune serum provided by the Butantan Institute for treatment of accidents with these spiders was also used. Separation by SDS-PAGE showed the existence of many common components in the three antigens. No individual antigen was observed. Analysis of the antisera by ELISA and Western blotting showed cross-reactivity as well as several common bands between the three venoms. The horse anti-L. gaucho venom serum recognized many common proteins when antigens of the other two species were used. Antigens in the range of 33,000-35,000 mol. wt showed most cross-reactivity. Both horse and rabbit anti-venom sera contained antibodies able to neutralize the lethal and dermonecrotic activities of the venom of the three species studied.
Asunto(s)
Especificidad de Anticuerpos , Antivenenos/inmunología , Venenos de Araña/inmunología , Animales , Western Blotting , Brasil , Reacciones Cruzadas/inmunología , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Ratones , Pruebas de Neutralización , Conejos , Venenos de Araña/análisisRESUMEN
Six neurotoxic peptides (Tx3-1 to Tx3-6) were purified from the venom of the spider Phoneutria nigriventer by a combination of gel filtration, reverse phase FPLC on PEP-RPC and PRO-RPC columns, reverse phase HPLC on Vydac C18, and ion exchange HPLC on cationic and anionic columns. These toxins caused different neurological symptoms in mice after intracerebroventricular injection. At dose levels of 5 micrograms/mouse, Tx3-3 and Tx3-4 caused rapid general flaccid paralysis followed by death in 10-30 min; Tx3-2 induced immediate clockwise gyration and flaccid paralysis after 6 hr; Tx3-1, Tx3-5 and Tx3-6 produced paralysis only in the posterior limbs and gradual decreases in movement and aggression during 24 hr. The mol. wt of these cystine-rich peptides were found to be in the range of 3500-8500 by mass spectroscopy and SDS-PAGE. The complete amino acid sequences of the neurotoxins Tx3-1 (40 residues), Tx3-2 (34 residues) and Tx3-6 (55 residues), and the N-terminal sequences of Tx3-3 (34 res.), Tx3-4 (40 res.) and Tx3-5 (36 res.) were established by direct automated Edman degradation, and manual DABITC/PITC microsequence analyses of peptides obtained from digests with various proteases. The structures of these Tx3 neurotoxins from Phoneutria nigriventer exhibited sequence similarities to one another and to the neurotoxins from the venoms of the spiders Hololena curta and Agelenopsis aperta, which were most evident in the location of the Cys residues.
Asunto(s)
Neurotoxinas/aislamiento & purificación , Venenos de Araña/química , Secuencia de Aminoácidos , Animales , Ratones , Datos de Secuencia Molecular , Neurotoxinas/químicaRESUMEN
Four neurotoxic polypeptides (Tx2-1, Txt2-5, Tx2-6 and Tx2-9) were purified from the venom of the South American 'armed' spider Phoneutria nigriventer (Keys) by gel filtration and reverse phase FPLC and HPLC. These cysteine-rich polypeptides exhibited different levels of neurotoxicity in mice after intracerebroventricular injection. Tx2-1, Tx2-5 and Tx2-6 caused spastic paralysis and death, but the less toxic Tx2-9 produced only tail erection and scratching. The molecular weights of the polypeptides as determined by desorption mass spectroscoopy were 5838.8 for Tx2-1, 5116.6 (Tx2-5), 5291.3 (Tx2-6) and 3742.1 (Tx2-9). The complete amino acid sequences of the neurotoxins were determined by automated Edman degradation and by manual DABITC-PITC microsequence analysis of peptides obtained after digestions with various proteases. The amino acid sequences of Tx2-1 (53 residues), Tx2-5 (49 residues) and Tx2-6 (48 residues) were homologous, but had only limited similarities to the less toxic Tx2-9 (32 residues). All four polypeptides had varying sequence identities with other neurotoxins from different spider species and biologically active peptides from scorpions, a sea snail and seeds of Mirabilis jalapa.
Asunto(s)
Neuropéptidos/aislamiento & purificación , Neurotoxinas/aislamiento & purificación , Venenos de Araña/química , Secuencia de Aminoácidos , Animales , Cromatografía en Gel , Cromatografía Líquida de Alta Presión , Cobayas , Íleon/efectos de los fármacos , Técnicas In Vitro , Datos de Secuencia Molecular , Músculo Liso/efectos de los fármacos , Neuropéptidos/química , Neuropéptidos/toxicidad , Neurotoxinas/química , Neurotoxinas/toxicidad , Homología de Secuencia , Homología de Secuencia de Ácido Nucleico , Venenos de Araña/toxicidadRESUMEN
The presence and specificity of IgG antibodies produced by patients with loxoscelism were studied. The loxoscelism diagnosis was supported mainly by clinical parameters. A search for IgG antibodies anti-Loxosceles gaucho venom in patients with loxoscelism submitted to serumtherapy showed antibodies in four out of 20 patients. The IgG antibodies were detected as early as 9 days and as late as 120 days after bite. The highest IgG antibody titer was 1:640 and the lowest was 1:80. Immunoblotting tests showed that human anti-L. gaucho IgG antibodies recognize preferentially the components responsible for the dermonecrotic and lethal activities of the venom. A comparison of the clinical picture, the level of serum IgG antibodies and the dose of antivenom administered suggest that there is no relationship between these parameters.
Asunto(s)
Antivenenos/inmunología , Inmunoglobulina G/inmunología , Picaduras de Arañas/inmunología , Venenos de Araña/inmunología , Electroforesis en Gel de Poliacrilamida , Humanos , ImmunoblottingRESUMEN
Loxosceles gaucho spider venom causes a typical dermonecrotic lesion in bitten patients and rarely causes lethal systemic effects. Gel filtration on Sephadex G 100 of L. gaucho spider venom resulted in three fractions: fraction A, containing the higher mol. wt components (approximately 35,000); fraction B, containing lower mol. wt components (approximately 15,000); and fraction C, containing very low mol. wt components (probably small peptides). The dermonecrotic and lethal activities were detected exclusively in fraction A. The venom and fraction A produced large dermonecrotic lesions in rabbits with necrosis spreading by gravity to the skin of the lateral body wall. Analysis by SDS-PAGE showed that the proteins contained in fraction A are approximately 35,000 and 33,000 mol. wt. Immunoblotting analysis showed that the proteins responsible for the dermonecrotic and lethal activity are very immunogenic and the first to be detected by antibodies during the course of immunization.
Asunto(s)
Dermotoxinas/toxicidad , Hidrolasas Diéster Fosfóricas/toxicidad , Venenos de Araña/toxicidad , Animales , Formación de Anticuerpos , Cromatografía en Gel , Dermotoxinas/química , Dermotoxinas/inmunología , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Inmunización , Immunoblotting , Dosificación Letal Mediana , Ratones , Ratones Endogámicos A , Peso Molecular , Necrosis/inducido químicamente , Hidrolasas Diéster Fosfóricas/química , Hidrolasas Diéster Fosfóricas/inmunología , Proteínas/análisis , Proteínas/toxicidad , Conejos , Piel/patología , Venenos de Araña/química , Venenos de Araña/inmunologíaRESUMEN
Foram analisados 242 acidentes atribuídos a aranhas do gênero Loxosceles Heinecken & Lowe atendidos no Hospital Vital Brazil do Instituto Butantan (1980-1984). L. gaucho Gertsch foi o agente agresssor mais comum e a espécie capturada com maior frequência nos locais de acidente vistoriados. L. laeta e L. intermedia Mello-Leitäo também estiveram representados no material estudado. Noçöes de reconhecimento e biologia dessas aranhas assim como a distribuiçäo geográfica das espécies brasileiras foram incluídas, para orientaçäo de médicos e pessoal relacionado a acidentes por animais peçonhentos. Os sinais característicos de síndrome loxoscélica e sua frequência na casuística em estudo foram mencionados e uma comparaçäo foi feita com dados correspondentes encontrados na literatura sulamericana