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1.
Rev Alerg Mex ; 67(2): 199-201, 2020.
Artigo em Espanhol | MEDLINE | ID: mdl-32892535
2.
Sci Rep ; 9(1): 14088, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31575961

RESUMO

Inhibitors targeting ion channels are useful tools for studying their functions. Given the selectivity of any inhibitor for a channel is relative, more than one inhibitor of different affinities may be used to help identify the channel in a biological preparation. Here, we describe a family of small proteins in centipede venoms that inhibit the pore (hKir6.2) of a human ATP-sensitive K+ channel (hKATP). While the traditional peptide-sequencing service gradually vanishes from academic institutions, we tried to identify the sequences of inhibitory proteins purified from venoms by searching the sequences of the corresponding transcriptomes, a search guided by the key features of a known hKir6.2 inhibitor (SpTx1). The candidate sequences were cross-checked against the masses of purified proteins, and validated by testing the activity of recombinant proteins against hKir6.2. The four identified proteins (SsdTx1-3 and SsTx) inhibit hKATP channels with a Kd of <300 nM, compared to 15 nM for SpTx1. SsTx has previously been discovered to block human voltage-gated KCNQ K+ channels with a 2.5 µM Kd. Given that SsTx inhibits hKir6.2 with >10-fold lower Kd than it inhibits hKCNQ, SsTx may not be suitable for probing KCNQ channels in a biological preparation that also contains more-SsTx-sensitive KATP channels.


Assuntos
Venenos de Artrópodes/farmacologia , Artrópodes , Canais de Potássio Corretores do Fluxo de Internalização/antagonistas & inibidores , Animais , Venenos de Artrópodes/genética , Venenos de Artrópodes/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Humanos , Transcriptoma/genética
3.
Artigo em Inglês | MEDLINE | ID: mdl-30448590

RESUMO

Megalopygids Megalopyge lanata and Podalia orsilochus are common causative agents of accidents in agricultural workers. These accidents are provoked by dermal contact at their larval stage and are characterized by cutaneous reactions, such as burning pain, edema and erythema, typically mild and self-limited. There is very little information about their venoms and their toxicological implications on human health. Thus, we employed proteomic techniques and biological assays to characterize venoms (bristle extracts) from caterpillars of both species collected from Misiones, Argentina. The electrophoretic profiles of both venoms were substantially different, and they presented proteins related to toxicity, such as serinepeptidases, serpins and lectins. P. orsilochus venom exhibited higher caseinolytic activity than M. lanata venom, agreeing with the fact that only P. orsilochus venom hydrolyzed human fibrin(ogen). In addition, the latter shortened the clotting time triggered by calcium. While the venom of M. lanata induced a mild inflammatory lesion in mouse skin, P. orsilochus venom caused prominent necrosis, inflammatory infiltration and hemorrhage at the site of venom injection. On the other hand, P. orsilochus venom was better recognized by Lonomia obliqua antivenom, although many of its proteins could not be cross-reacted, what may explain the difference in the clinical manifestations between accidents by Podalia and those by Lonomia. Altogether, this study provides relevant information about the pathophysiological mechanisms whereby both caterpillars can induce toxicity on human beings, and paves the way for novel discovery of naturally occurring bioactive compounds.


Assuntos
Venenos de Artrópodes/toxicidade , Mordeduras e Picadas de Insetos/etiologia , Mariposas , Animais , Venenos de Artrópodes/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Humanos , Larva/anatomia & histologia , Masculino , Espectrometria de Massas , Camundongos , Mariposas/anatomia & histologia , Pele/efeitos dos fármacos
4.
Toxicon ; 146: 120-123, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29510162

RESUMO

A straightforward method for extracting aculeate arthropod venoms by centrifugation is described, based on adapting a glass insert containing a piece of metal mesh or glass wool into a centrifuge tube. Venom apparatuses are centrifuged for 30 s intervals at ≈2000-6000 g, with samples being dislodged between cycles. Venom from fire ants, honeybees, and a social wasp were extracted within minutes. The method is suited for small-scale bioassays and allows for faithful descriptions of unmodified toxin cocktails.


Assuntos
Venenos de Artrópodes/isolamento & purificação , Centrifugação/métodos , Animais , Formigas , Abelhas , Vespas
5.
Ann Allergy Asthma Immunol ; 118(5): 531-536, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28477785

RESUMO

OBJECTIVE: To review allergenic extracts used to diagnose or treat insect allergies, including how the extracts are manufactured and their measurements of potency or concentration. DATA SOURCES: Peer-reviewed articles derived from searching PubMed (National Center for Biotechnology Information) about insect allergies and extract preparation. Encyclopedia of Life (http://www.eol.org/) and http://allergome.org/ were also referenced for background information on insects and associated allergens. STUDY SELECTIONS: Search terms used for the PubMed searches included insect allergens and allergies, Apidae, Vespidae, fire ants, cockroach allergies, insect allergen extract preparation, and standardization. RESULTS: Humans may be sensitized to insect allergens by inhalation or through stings. Cockroaches and moths are predominantly responsible for inhalation insect allergy and are a major indoor allergen in urban settings. Bees, fire ants, and wasps are responsible for sting allergy. In the United States, there are multiple insect allergen products commercially available that are regulated by the US Food and Drug Administration. Of those extracts, honeybee venom and insect venom proteins are standardized with measurements of potency. The remaining insect allergen extracts are nonstandardized products that do not have potency measurements. CONCLUSION: Sensitization to inhalational and stinging insect allergens is reported worldwide. Crude insect allergen extracts are used for diagnosis and specific immunotherapy. A variety of source materials are used by different manufacturers to prepare these extracts, which may result in qualitative differences that are not reflected in measurements of potency or protein concentration.


Assuntos
Alérgenos/imunologia , Venenos de Artrópodes/imunologia , Dessensibilização Imunológica , Hipersensibilidade/diagnóstico , Hipersensibilidade/terapia , Mordeduras e Picadas de Insetos/diagnóstico , Mordeduras e Picadas de Insetos/terapia , Alérgenos/isolamento & purificação , Animais , Venenos de Artrópodes/isolamento & purificação , Humanos , Imunização , Inalação
6.
Toxicon ; 118: 156-61, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27158113

RESUMO

Extracting venom from small species is usually challenging. We describe here an affordable and versatile electrical venom extractor based on the Arduino(®) Mega 2560 Board, which is designed to extract venom from arthropods and other small animals. The device includes fine tuning of stimulation time and voltage. It was used to collect venom without apparent deleterious effects, and characterized for the first time the venom of Zoropsis spinimana, a common spider in French Mediterranean regions.


Assuntos
Manejo de Espécimes/instrumentação , Venenos de Aranha/isolamento & purificação , Aranhas/fisiologia , Animais , Proteínas de Artrópodes/análise , Proteínas de Artrópodes/química , Proteínas de Artrópodes/economia , Proteínas de Artrópodes/isolamento & purificação , Venenos de Artrópodes/química , Venenos de Artrópodes/economia , Venenos de Artrópodes/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Custos e Análise de Custo , Equipamentos e Provisões Elétricas/economia , Desenho de Equipamento , França , Teste de Materiais , Região do Mediterrâneo , Peso Molecular , Restrição Física/instrumentação , Manejo de Espécimes/economia , Espectrometria de Massas por Ionização por Electrospray , Venenos de Aranha/química , Venenos de Aranha/economia , Aranhas/crescimento & desenvolvimento
7.
Toxicon ; 90: 308-17, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25172536

RESUMO

In the past 100 years minimal venom research has focused on ticks despite several species possessing a highly paralytic and lethal venom cocktail of proteinaceous molecules. The saliva of the Australian paralysis tick, Ixodes holocyclus, has been responsible for 20 human fatalities from 1900 to 1945, and up to 100,000 domestic animal fatalities annually. In the last 50 years, research on this tick has focused on identifying the neurotoxins present in the saliva and in the last ten years the sequence of a potential neurotoxin, HT-1, has been determined. In this study we chemically synthesised HT-1 using Boc-chemistry in combination with native chemical ligation. Following successful oxidative folding, we determined the three-dimensional structure of HT-1 by NMR spectroscopy and found a novel structural fold with three of the four disulfide bonds comprising the inhibitory cystine knot (ICK) motif. The fourth disulfide bond connects the second loop to the N-terminal, which decreases the flexibility of the structure.


Assuntos
Venenos de Artrópodes/isolamento & purificação , Cisteína/química , Ixodes/química , Sequência de Aminoácidos , Animais , Venenos de Artrópodes/química , Venenos de Artrópodes/toxicidade , Cromatografia Líquida de Alta Pressão , Dados de Sequência Molecular , Ressonância Magnética Nuclear Biomolecular , Espectrometria de Massas em Tandem
8.
Biosci Biotechnol Biochem ; 77(1): 205-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23291760
9.
Toxicon ; 55(1): 33-44, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19577588

RESUMO

Envenomation caused by Lonomia obliqua is a public health hazard in Southern Brazil. Envenomed victims present severe hemorrhagic syndrome that can progress to intracranial hemorrhage and death. To understand the mechanisms that lead to hemorrhage, we investigated the platelet dysfunction and blood coagulation disturbances following experimental envenomation in rats. L. obliqua bristle extract was injected (s.c.) and blood collected at different times post-venom administration for determination of platelet response and analysis of blood coagulation. Rats presented hypofibrinogenemia and platelet hypoaggregation in platelet rich plasma (PRP). After addition of exogenous fibrinogen to PRP, platelet hypoaggregation was not corrected. Interestingly, normoaggregation was observed when platelets were separated from plasma. In addition, incubation of plasma from envenomed rats inhibits aggregation response of normal washed platelets. These results indicate that an aggregation inhibitor is generated in plasma during envenomation. Moreover, rats presented an increase in nitric oxide plasmatic levels which coincided with maximum inhibition in platelet aggregation. Animals also showed blood incoagulability and a significant increase in thrombin, plasmin and urokinase plasmatic activities. Despite this intravascular thrombin generation, only a slight decrease in platelet numbers was detected. Certainly, the platelet hypoaggregation and blood incoagulability described herein contribute to systemic bleeding observed in patients.


Assuntos
Venenos de Artrópodes/toxicidade , Coagulação Sanguínea/efeitos dos fármacos , Mordeduras e Picadas de Insetos/complicações , Mariposas/química , Agregação Plaquetária/efeitos dos fármacos , Animais , Venenos de Artrópodes/isolamento & purificação , Brasil , Modelos Animais de Doenças , Fibrinogênio/análise , Hemorragia/etiologia , Hemorragia/mortalidade , Mordeduras e Picadas de Insetos/sangue , Mordeduras e Picadas de Insetos/mortalidade , Larva/química , Masculino , Nitratos/sangue , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Nitritos/sangue , Inibidores da Agregação Plaquetária/sangue , Ratos , Ratos Wistar , Fatores de Tempo
10.
Blood Coagul Fibrinolysis ; 17(6): 427-35, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16905945

RESUMO

Lonomia achelous is a caterpillar distributed in southern Venezuela and in northern Brazil that causes an acute hemorrhagic syndrome in people who have contact with its bristles. The effect of the crude hemolymph and its chromatographic fractions (FDII, Lonomin V and Lonomin V-2) on extracellular matrix proteins was studied. The chromatographic fractions show activities similar to plasmin and urokinase. In sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both lonomins appear as a protein band of 25 kDa under reduced conditions. By exclusion chromatography, the molecular weights of Lonomin V and Lonomin V-2 were 26.5 and 24.5 kDa, respectively. Fibronectin, laminin and vitronectin were degraded by all venom components. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, under reduced conditions, shows that lonomins degrade fibronectin in four main fragments of 116, 60, 50 and 30 kDa. Molecular exclusion chromatography in native conditions shows that the molecular masses of these fragments are > or = 300, 62 and 27 kDa. The proteolytic effect of lonomins was abolished by benzamidine/HCl, iodoacetic acid and aprotinin. The extracellular matrix protein degradation together with the fibrino(geno)lytic activity of hemolymph and its fractions could explain, in part, the hemorrhagic syndrome, and the wound dehiscence in persons who have had contact with the L. achelous caterpillar.


Assuntos
Venenos de Artrópodes/farmacologia , Proteínas da Matriz Extracelular/efeitos dos fármacos , Hemolinfa/enzimologia , Mariposas/enzimologia , Serina Endopeptidases/farmacologia , Animais , Venenos de Artrópodes/isolamento & purificação , Cromatografia em Agarose , Fibronectinas/efeitos dos fármacos , Hemorragia/induzido quimicamente , Hemorragia/enzimologia , Hemostasia/efeitos dos fármacos , Hemostasia/fisiologia , Humanos , Laminina/efeitos dos fármacos , Serina Endopeptidases/isolamento & purificação , Vitronectina/efeitos dos fármacos
11.
Comp Biochem Physiol C Toxicol Pharmacol ; 135(2): 205-14, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12860060

RESUMO

A toxic fraction from centipede (Scolopendra sp.) venom was tested in neurotransmitter release experiments. The venom was fractionated by DEAE-cellulose with a linear gradient from 20 mM to 1.0 M of ammonium acetate pH 4.7. Lethality tests were performed by injections into the third abdominal dorsolateral segment of sweet water crayfishes of the species Cambarellus cambarellus. Only fraction V (TF) was toxic. Analysis by SDS-PAGE showed that this fraction contains at least seven proteins. It induces an increase of basal gamma-amino butyric acid (GABA) and glutamate release from ventral abdominal ganglia of C. cambarellus. Assays conducted with this fraction in the presence of several drugs that affect ion channel function suggested that TF modifies membrane permeability by increasing basal release of neurotransmitters was very likely through sodium channels.


Assuntos
Venenos de Artrópodes/farmacologia , Crustáceos/efeitos dos fármacos , Gânglios dos Invertebrados/efeitos dos fármacos , Gânglios dos Invertebrados/metabolismo , Neurotransmissores/metabolismo , 4-Aminopiridina/farmacologia , Animais , Venenos de Artrópodes/isolamento & purificação , Cálcio/metabolismo , Crustáceos/metabolismo , Eletroforese em Gel de Poliacrilamida , Ácido Glutâmico/metabolismo , Tetrodotoxina/farmacologia , Ácido gama-Aminobutírico/metabolismo
12.
Thromb Res ; 102(5): 427-36, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11395128

RESUMO

Lonomia obliqua venom causes a severe consumptive coagulopathy, which can lead to a hemorrhagic syndrome. The crude bristles extract displays a procoagulant activity due to a Factor X and to a prothrombin activating activity. Here, we describe a 69 kDa prothrombin activator serine protease purified from L. obliqua caterpillar bristle extract using gel filtration (Sephadex G 75) and HPLC (C(4) column). The purified protein was able to activate prothrombin in a dose-dependent manner, and calcium ions increased this activity. The prothrombin-derived fluorogenic peptide (Abz-YQTFFNPRTGSQ-EDDnp) had its main cleavage site at the Arg-Thr bond. The kinetic parameters obtained for this substrate were Kmapp of 4.5 microM, kcat of 5.32 s(-1), and a kcat/Kmapp of 1.2 x 10(6) M(-1) s(-1). The prothrombin fragments generated by the purified enzyme corresponded to the molecular masses of prethrombin 2, fragment 1, fragment 2, and thrombin as seen in SDS-PAGE. The thrombin generated was able to clot purified fibrinogen. The partial amino acid sequence of the purified protein, named Lopap (L. obliqua prothrombin activator protease), showed no similarity to any known prothrombin activator.


Assuntos
Protrombina/metabolismo , Serina Endopeptidases/farmacologia , Sequência de Aminoácidos , Animais , Venenos de Artrópodes/isolamento & purificação , Venenos de Artrópodes/farmacologia , Sítios de Ligação , Testes de Coagulação Sanguínea , Cálcio/farmacologia , Relação Dose-Resposta a Droga , Fator X/metabolismo , Fibrinogênio/efeitos dos fármacos , Fibrinogênio/metabolismo , Corantes Fluorescentes/metabolismo , Humanos , Cinética , Larva , Lepidópteros , Dados de Sequência Molecular , Serina Endopeptidases/isolamento & purificação
13.
Thromb Res ; 102(5): 437-43, 2001 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-11395129

RESUMO

Increasing occurrence of hemorrhagic syndrome in man, caused by contact with Lonomia obliqua caterpillars, has been reported in Southern Brazil in the past 10 years. The L. obliqua venom causes a severe consumptive coagulopathy, which can lead to hemorrhagic syndrome. L. obliqua prothrombin activator protease (Lopap) is a 69-kDa prothrombin activator serine protease isolated from L. obliqua caterpillar bristle extract, which is able to evoke thrombus formation, unclottable blood, and fibrinogen depletion when injected into the blood stream of rats. The purified protein generated thrombin from prothrombin, able to clot purified human fibrinogen and plasma. A decrease in platelet count and inhibition of collagen-induced platelet aggregation were observed, as well as leukocyte infiltration in the lungs. In addition, we observed congestion and hemorrhage in renal glomeruli and necrosis in renal distal tubules. These data support the hypothesis that Lopap contributes to the clinical syndrome caused by human contact with L. obliqua, most probably through prothrombin activation, resulting in a consumption coagulopathy.


Assuntos
Serina Endopeptidases/farmacologia , Animais , Venenos de Artrópodes/isolamento & purificação , Venenos de Artrópodes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Humanos , Rim/irrigação sanguínea , Rim/efeitos dos fármacos , Rim/patologia , Larva , Lepidópteros , Pulmão/irrigação sanguínea , Pulmão/efeitos dos fármacos , Pulmão/patologia , Masculino , Microcirculação/efeitos dos fármacos , Microcirculação/patologia , Microscopia de Vídeo , Especificidade de Órgãos , Contagem de Plaquetas , Ratos , Ratos Wistar , Serina Endopeptidases/isolamento & purificação , Trombose/induzido quimicamente
14.
Haemostasis ; 31(3-6): 294-305, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11910198

RESUMO

Anticoagulant activities against the extrinsic and intrinsic coagulation pathways were identified in salivary gland extracts (SGE) prepared from four tabanids (Hybomitra muehlfeldi, Tabanus autumnalis, Haematopota pluvialis, Heptatoma pellucens). All extracts prolonged human plasma clotting time in a dose-dependent manner and inhibited thrombin activity in the chromogenic substrate assay. Horsefly SGE did not inhibit factor Xa. Partial purification of SGE proteins using reversed-phase high-performance liquid chromatography revealed species-specific differences in the elution profiles and range of fractions with anticoagulant activities.


Assuntos
Anticoagulantes/isolamento & purificação , Venenos de Artrópodes/isolamento & purificação , Venenos de Artrópodes/farmacologia , Glândulas Salivares/química , Animais , Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Testes de Coagulação Sanguínea , Extratos Celulares , Cromatografia Líquida de Alta Pressão , Dípteros/química , Fator Xa/efeitos dos fármacos , Humanos , Especificidade da Espécie , Trombina/antagonistas & inibidores
15.
Thromb Res ; 93(5): 243-52, 1999 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-10074908

RESUMO

Contact with Lonomia achelous caterpillars venom induces a severe bleeding syndrome in humans. A constant finding in all reported cases is a marked decrease of blood coagulation factor XIII (FXIII), which has been attributed to the presence of a proteolytic enzyme, isolated and named Lonomin V, in the hemolymph and hair secretion. In this study, the effect of Lonomin V on transglutaminase activity from human plasma, rabbit plasma, and platelet FXIII was analyzed. The decrease of activity was more pronounced in platelet (A2) when compared with rabbit plasma (AB) and human plasma FXIII (A2B2). This finding might be explained by the differences in FXIII molecular structure. In addition, platelet FXIII molecule was degraded by Lonomin to several fragments of low molecular mass. Lonomin V was stable over a wide range of pH (6-8.5) and temperatures of -70 degrees C, -20 degrees C and between 4 to 24 degrees C, with a progressive decrease at 37 degrees C and total inactivation at 60 degrees C after 2 hours incubation. Diisopropyl fluoro-phosphate, phenylmethylsulfonyl fluoride, tosyl-l-lysine chloromethyl ketone, and iodoacetamide abolished the effect of Lonomin V on FXIII; in contrast dithiothreitol and EDTA-Na enhance the activity. We concluded that Lonomin V is a serine proteinase with a free Cys essential for the enzymatic activity. Due to its proteolytic activity on FXIII, with concomitant impairment of fibrin cross-linking, Lonomin V might be useful in association with thrombolytic drugs for preventing rethrombosis.


Assuntos
Anticoagulantes/química , Venenos de Artrópodes/química , Plaquetas/efeitos dos fármacos , Fator XIII/antagonistas & inibidores , Mariposas/química , Animais , Anticoagulantes/farmacologia , Venenos de Artrópodes/isolamento & purificação , Venenos de Artrópodes/farmacologia , Plaquetas/metabolismo , Eletroforese em Gel de Poliacrilamida , Humanos , Concentração de Íons de Hidrogênio , Coelhos , Temperatura
16.
Zhong Yao Cai ; 20(1): 36-7, 1997 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-12572496

RESUMO

The hemolysis of toxins from alive Scolopendra subspinipes mutilans, medicinal material of Scolopendra subspimipes mutilans and S. multidens have been compared. The result shows that all the toxins have hemolytic activity. The hemolytic activity of the toxin from the medicinal materials of S. subspinipes mutilans is obviously lower than that from alive ones, and that from fresh medicinal materials are twice as high that from old ones, and that from S. multidens is higher than that from S. subspinipes multilans.


Assuntos
Venenos de Artrópodes/farmacologia , Artrópodes/química , Hemólise/efeitos dos fármacos , Materia Medica/farmacologia , Toxinas Biológicas/farmacologia , Animais , Venenos de Artrópodes/isolamento & purificação , Artrópodes/classificação , Materia Medica/isolamento & purificação , Coelhos , Espectrofotometria Ultravioleta , Toxinas Biológicas/isolamento & purificação
17.
Toxicon ; 34(11-12): 1421-9, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9027999

RESUMO

A review is presented of our ongoing research projects on the protein components of the saliva of human body lice and of the non-paralyzing venom of wasps in the subfamily Cheloninae. Sodium dodecyl sulfate-polyacryamide gel electrophoretic analysis of lice salivary gland proteins showed a predominance of high and intermediate mol. wt proteins. Immunoblotting with a low titer polyclonal antiserum to lice salivary proteins indicated that some, but not all, of the predominant high mol. wt salivary gland proteins are injected into the host during feeding. The venom of a Chelonus sp. wasp contains a chitinase, and a 33,000 mol. wt protein with a primary structure composed mostly of a series of 12 tandem repeats of a 14-residue sequence. The N-terminus of this protein and its homologs in a related species of Ascogaster share a conserved adjacent pair of acidic residues. Epitope mapping/immunoprecipitation experiments now in progress will provide information on which linear motifs are on the surface of the protein, and will thereby provide information on the tertiary structure of the protein.


Assuntos
Venenos de Artrópodes/biossíntese , Venenos de Artrópodes/toxicidade , Mariposas/parasitologia , Ftirápteros/metabolismo , Proteínas e Peptídeos Salivares/biossíntese , Proteínas e Peptídeos Salivares/toxicidade , Toxinas Biológicas/biossíntese , Venenos de Vespas/biossíntese , Venenos de Vespas/toxicidade , Vespas/metabolismo , Animais , Venenos de Artrópodes/isolamento & purificação , Humanos , Ftirápteros/química , Proteínas e Peptídeos Salivares/isolamento & purificação , Venenos de Vespas/isolamento & purificação , Vespas/química , Vespas/crescimento & desenvolvimento
18.
Toxicon ; 33(12): 1549-55, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-8866612

RESUMO

Modern analytical techniques permit isolation and structural determination of neurotoxins at the picomole level. However, bioassay-guided fractionation of the sample often relies on simple injection assays using insects, vertebrates or crustaceans of a fairly large size, thus consuming quite a large amount of the samples being investigated. In order to investigate samples of very small size, we have devised an insect microinjection method using glass micropipettes and Drosophila melanogaster adults as test insects. The validity of the method was tested with a series of six buthoid scorpion venoms (Androctonus australis, Buthotus judaicus, Buthus tamulus, Centruroides sculpturatus, Leiurus quinquestriatus hebraeus, Tityus serrulatus) and one chactoid scorpion (Scorpio maurus palmatus) as standards. The LD50S of the venoms were determined using both the microinjection method and a classical injection assay with crickets (Gryllus bimaculatus) as test insects. Results demonstrated that the new method can successfully be applied to the study of insect neurotoxic activity in arthropod venoms. The Gryllus:Drosophila ratio in amount of sample utilized is 100. However, for all Buthoid venoms tested, except L. quinquestriatus, Drosophila showed less sensitivity, thus reducing the gain by a factor of 2-10. Drosophila were several times more sensitive to the only chactoid venom tested. These results clearly demonstrate the advantage of using this microtechnique, when limited amounts of material are available for both chemical and biological work.


Assuntos
Venenos de Artrópodes/toxicidade , Neurotoxinas/toxicidade , Animais , Venenos de Artrópodes/química , Venenos de Artrópodes/isolamento & purificação , Venenos de Artrópodes/metabolismo , Artrópodes , Simulação por Computador , Drosophila/efeitos dos fármacos , Gryllidae , Dose Letal Mediana , Microinjeções/métodos , Neurotoxinas/química , Neurotoxinas/isolamento & purificação , Neurotoxinas/metabolismo , Paralisia/induzido quimicamente , Padrões de Referência , Venenos de Escorpião/química , Venenos de Escorpião/isolamento & purificação , Venenos de Escorpião/metabolismo , Venenos de Escorpião/toxicidade , Relação Estrutura-Atividade
19.
Biochem Biophys Res Commun ; 215(1): 167-71, 1995 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-7575586

RESUMO

A toxic substance was purified from larvae of the antilion, Myrmeleon bore, by DEAE Sephacel and Phenyl Superose column chromatography. The substance was a large polypeptide with a molecular weight of about 165-167 kDa. Its paralytic activity measured by injection against German cockroaches was about 130 times higher than that of tetrodotoxin on a molar basis.


Assuntos
Venenos de Artrópodes/isolamento & purificação , Insetos , Peptídeos/isolamento & purificação , Toxinas Biológicas/isolamento & purificação , Peçonhas/química , Sequência de Aminoácidos , Animais , Venenos de Artrópodes/química , Venenos de Artrópodes/farmacologia , Baratas/efeitos dos fármacos , Larva/metabolismo , Dados de Sequência Molecular , Peso Molecular , Fragmentos de Peptídeos/química , Peptídeos/química , Peptídeos/farmacologia , Tetrodotoxina/farmacologia , Toxinas Biológicas/química , Toxinas Biológicas/farmacologia
20.
Toxicon ; 33(5): 659-65, 1995 May.
Artigo em Inglês | MEDLINE | ID: mdl-7660370

RESUMO

Two polypeptides from the venom of Polybia scutellaris were purified to homogeneity by RP-HPLC. They differ very slightly in mol. wt (both are about 23,000) and hydrophobicity, and have isoelectric points greater than 9. Amino acid analyzes show close similarity between them and with antigen 5 of vespids from different species. The two polypeptides have an identical N-terminal sequence (18 amino acids) which shows a high degree of homology with those of other vespids. Owing to the fact that the venom of this species is non-allergenic, the data for the mol. wt, isoelectric point, amino acid composition and N-terminal sequence allow us to identify the isolated polypeptides as two forms of antigen 5. Amino acids at positions 5 and 11 in P. scutellaris antigen 5 differ from those of the previously known sequences for antigen 5, suggesting that one or other might be responsible for the lack of allergenicity of the P. scutellaris venom.


Assuntos
Antígenos/análise , Antígenos/isolamento & purificação , Venenos de Artrópodes/química , Venenos de Artrópodes/isolamento & purificação , Alérgenos/isolamento & purificação , Sequência de Aminoácidos , Aminoácidos/análise , Animais , Venenos de Artrópodes/análise , Dados de Sequência Molecular
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