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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Mediação química da hiperagesia induzida pelos venenos de serpentes Bothrops jararaca e Bothrops asper e por uma miotoxina com atividade de fosfolipase A2 isolada do veneno de Bothrops asper / Chemical mediation of hyperalgesia induced by Bothrops jararaca and Bothrops asper snake venoms and by a phospholipase A2 miotoxin isolated from Bothrops asper venom.

Marucia Chacur 01 December 2000 (has links)
Os venenos do gênero Bothrops induzem efeitos locais caracterizados por hemorragia, necrose, edema e dor intensa. Apesar da importância clínica do fenômeno de dor, os estudos sobre os mecanismos envolvidos na gênese deste fenômeno são ainda escassos. Além disso, não existem dados sobre a capacidade do antiveneno em neutralizar este fenômeno. Neste trabalho foi investigada, a capacidade dos venenos de Bothrops jararaca, Bothrops asper e da miotoxina III (Fosfolipase A2, variante Asp 49), uma toxina isolada do veneno de Bothrops asper, em induzir hiperalgesia em ratos, a mediação química deste fenômeno e a capacidade dos antivenenos em neutralizar esta ação dos venenos. A possível correlação entre a hiperalgesia e a resposta edematogênica causada pelos venenos ou miotoxina foi também avaliada. O limiar de dor foi determinado antes e em diferentes tempos após a administração dos venenos ou toxina, empregando o teste de pressão de pata de rato. Para o estudo da resposta edematogênica, o aumento do volume das patas posteriores foi determinado por pletismografia. Os venenos e a toxina, administrados por via intraplantar, nas doses de 5µg (VBj), 15µg (VBa) ou 10µg (MIII), induziram hiperalgesia e edema, com respostas máxima na 1a (VBj, MIII) ou 2a (VBa) hora, não sendo mais detectadas na 24a hora. Para o estudo da neutralização, foram utilizados o antiveneno botrópico produzido no Instituto Butantan e o antiveneno polivalente produzido no Instituto Clodomiro Picado da Costa Rica, administrados por via endovenosa, 15 min. ou imediatamente antes ou 15 min. após a injeção dos venenos. O AVIB, quando injetado 15 min. antes do VBj, foi capaz de reverter a hiperalgesia induzida pelo veneno. Em relação ao edema, esta inibição foi observada quando o antiveneno foi administrado 15 min. ou imediatamente antes do VBj. Por outro lado, o AVCP não interferiu com a dor e o edema acarretados pelo VBa. Quando o VBj e o VBa foram incubados, in vitro, por 30 min., a 370C com os AV correspondentes, a hiperalgesia e o edema foram abolidos. Estes resultados indicam que a incapacidade do AVCP, quando administrado in vivo, de bloquear a hiperalgesia e o edema induzidos pelo VBa, não é consequência da ausência de anticorpos específicos no antiveneno, uma vez que estes efeitos foram inibidos quando o veneno foi pré-incubado com o antiveneno. Para avaliação da mediação química da hiperalgesia e do edema, os animais foram submetidos a tratamentos com inibidores de síntese, antagonistas de receptores, anticorpos ou drogas depletoras destes mediadores. Os resultados mostraram que o Hoe-140, dexametasona e NDGA inibem a hiperalgesia induzida pelo VBa, enquanto que apenas a prometazina interferiu com o edema causado pelo veneno. A hiperalgesia induzida pela MIII foi revertida pelo tratamento com prometazina, metisergida, Hoe-140, dexametasona e por NDGA, enquanto que o edema foi inibido apenas por prometazina e dexametasona. Estes dados sugerem que: a) a MIII é um importante componente do veneno para a geração de hiperalgesia, b) a bradicinina e os derivados da lipoxigenase são mediadores da dor acarretada pelo VBa e pela MIII, c) histamina e serotonina participam também da hiperalgesia induzida pela miotoxina e d) a histamina é mediador do edema induzido pelo VBa e pela MIII. Com relação à hiperalgesia induzida pelo VBj, somente o tratamento com Hoe-140 diminuiu este fenômeno, indicando a participação da bradicinina. Por outro lado, este tratamento não foi capaz de interferir com o edema induzido por este veneno. Cabe ressaltar que TEIXEIRA et al. (1994) demonstraram a participação de eicosanóides e PAF na hiperalgesia induzida pelo VBj. Os dados em conjunto sugerem ainda, dissociação entre os fenômenos de dor e edema acarretados por ambos os venenos e pela miotoxina. / Bothrops venoms cause pronounced local tissue-damage characterized by hemorrhage, myonecrosis, edema and pain. Venom-induced pain has been poorly investigated, despite its clinical relevance. Furthermore, the ability of antivenom to neutralize hyperalgesia induced by these venoms is not known. In the present study the hyperalgesia and edema induced by Bothrops jararaca (BjV) and Bothrops asper (BaV) venom and by myotoxin III-MIII (Asp49- phospholipase A2), a toxin isolated from BaV, were investigated. The chemical mediators involved in these phenomena and the ability of the antivenom to neutralize the hyperalgesia and edema induced by these venoms were also investigated. Pain threshold was assessed before and at several intervals after venom injection, using the rat paw pressure test. Edema of paw was measured phethysmographically at the same periods of time. The intraplantar injection of BjV (5µg/paw), BaV (15µg/paw) or MIII (10µg/paw) caused hyperalgesia and edema, whose peak were observed at the 1st (BjV, MIII) or 2nd (BaV) hours after venom/toxin administration, decreasing thereafter. For neutralization studies, the antivenoms produced either at Instituto Butantan from Brazil (AVIB) or Instituto Clodomiro Picado from Costa Rica (AVCP) were administered intravenously 15 min prior to, or immediately before, or 15 min after venoms injection. When the antivenom from Instituto Butantan was injected 15 min. before BjV, the hyperalgesia and edema were abolished. Furthermore, partial inhibition of edema was also observed when the antivenom was injected together with BjV. On the other hand, hyperalgesia and edema induced by BaV were not modified by AVCP. Incubation of BjV and BaV, for 30 min. at 37oC, with the antivenoms in vitro, abolished the hyperalgesia and edema. The inability of the in vivo treatment with antivenom in abolishing hyperalgesia and edema induced by BaV seems not to be related to the lack of neutralizing antibodies in antivenom, because neutralization was achieved in pre-incubation experiments. In order to investigate the chemical mediation of hyperalgesia and edema induced by the venoms or toxin, animals were treated with several drugs. Pretreatment with Hoe-140, dexamethasone and NDGA blocked the hyperalgesia induced by BaV, whereas only promethazine reduced the edema induced by this venom. The MIII-induced hyperalgesia was blocked by promethazine, methysergide, Hoe-140, dexamethasone and NDGA, whereas the edema was reduced only by promethazine and dexamethasone. These results suggest that: a) MIII may contribute to the BaV-induced hyperalgesia, b) bradykinin and leukotrienes mediate the BaV- and MIII-induced pain and MIII; c) histamine and serotonin also participate in the myotoxin-induced hyperalgesia and d) the edema induced by BaV and MIII is mediated by histamine. Pre-treatment of the animals with Hoe-140 abolished BjV-induced hyperalgesia, suggesting that bradykinin may mediate the venom-induced hyperalgesia. However, this treatment did not modify the BjV-induced edema. It is important to stress that previous studies have shown that BjV-induced hyperalgesia is mediated, at least partially, by eicosanoids and PAF (TEIXEIRA et al.,1994). The data presented herein also suggest that distinct mechanisms may be involved in the development of hyperalgesia and edema induced by both venoms and myotoxin III.
82

"Characterization of Red Diamondback Rattlesnake Venom Proteins on Cell Death and Function"

Ebrahimian, Venus January 2013 (has links)
No description available.
83

An evaluation of the homoeopathic drug proving of Naja Mossambica in the light of a doctrine of signatures analysis and a comparison between the proving symptons and the venom toxicology

Taylor, Liesel January 2004 (has links)
Thesis (M.Tech.: Homoeopathy)-Dept of Homoeopathy, Durban Institute of Technology, 2004 xiv, 154 leaves : ill. ; 30 cm / This study was conducted by administering Naja mossambica 30CH (a homoeopathic remedy derived from the venom of the Mozambican spitting cobra) to healthy individuals in order to elicit and document the resulting mental and physical symptomology. These symptoms were compared to the toxicology of Naja mossambica venom as well as a doctrine of signatures analysis of the snake in order to expand and clarify the remedy picture. Existing knowledge of the venom toxicology gives a clear indication of the organs and body systems that the substance has an affinity for. Many poisonous substances used homoeopathically rely heavily on inferences made from the toxicology of the substance, as much of the gross pathology in the symptom picture cannot safely be elucidated in a proving. The aim of this study was to determine the sphere of action of Naja mossambica by utilising symptoms obtained from the proving and from the toxicology of the venom. This was done in order to determine the remedy's usefulness in a homoeopathic clinical setting by expanding our understanding of the substance and thereby facilitating the treatment of disease based on the law of similars.
84

A homoeopathic drug proving of Bitis atropos and a subsequent comparison of results with that of existing proven remedies of the Genus Bitis

Schönfeld, Victoria-Leigh 13 June 2014 (has links)
Submitted in partial compliance with the requirements of the Master’s Degree in Technology: Homoeopathy, Durban University of Technology, 2013. / Introduction The aim of this study was to investigate the homeopathic potential of Bitis atropos 30CH (Homoeopathically prepared Berg adder venom) and to compare the materia medica of Bitis atropos with that of existing remedies originating from remedies derived from the same genus: Bitis. It was hypothesised that the thirtieth centesimal potency of the substance Bitis atropos would produce clearly observable signs and symptoms in healthy volunteers, furthermore it was hypothesised that the materia medica of Bitis atropos would be comparable with those of existing remedies originating from the genus Bitis. Methodology The homeopathic drug proving of the substance Bitis atropos 30CH took the form of a double-blinded, randomised, placebo controlled trial. A total of 28 provers took part in the proving, twenty one percent (6 provers) were randomly administered placebo, the other seventy nine percent (22 provers) were randomly administered verum (active proving drug). Each prover received six lactose powder sachets, either placebo or verum, and were instructed to take one powder three times a day or until symptoms arose. Symptoms induced in healthy provers by Bitis atropos or placebo were recorded in journal format on a daily basis for a period of 4 weeks or until symptoms subsided. This data was subsequently transcribed into nomenclature suitable for the materia medica and repertory. A general picture of the remedy was described which according to the Law of Similars forms the clinical indications of the substance in homoeopathic practice. A concurrent study of the proving of Bitis atropos 30CH was conducted by Brijnath (2013), and focused on comparing the results of the proving with the venom toxicology of the snake and other related remedies. Results A wide variety of mental, emotional and physical symptoms were produced. Some of the main themes included feelings of antagonism with one’s self, polarity, anxiety, irritability and a lack of focus with a feeling of confusion. Some of the physical symptoms produced were a lack of energy, fatigue, temperature sensitivity, skin eruptions, eye symptoms, ear symptoms, back pain, asthma symptoms, and an increase in libido. The symptoms from the proving of Bitis atropos 30CH were subsequently compared with remedies that belong to the same genus: Bitis. This analysis aimed to demonstrate the similarities between the remedies in the same genus: Bitis. A significant degree of similarity was noted within the mental sphere, where the remedies shared the same themes of anxiety, irritability, polarity, confusion and lack of mental focus. Some of the physical symptoms shared by the remedies were those of respiratory symptoms, temperature sensitivity, fatigue, lack of energy and headaches and an increased libido. Conclusion This investigation supported the hypothesis that Bitis atropos 30CH would produce clear and observable signs and symptoms in healthy volunteers in addition it supported the hypotheses that the materia medica produced would be comparable to the existing remedies sharing the same genus i.e.- Bitis arietans arietans(Puff adder) and Bitis gabonica gabonica (Gaboon viper).
85

Venom Variability and Health Severity Outcomes of the Mohave rattlesnake (Crotalus scutulatus scutulatus) from Southern Arizona

Curtis, Ryan, Richards, Kelvin January 2012 (has links)
Class of 2012 Abstract / Specific Aims: Determine the difference in venom potency among Mohave Rattlesnakes in Cochise in Pima Counties and determine if those differences correlate to changes in clinical outcomes. Methods: Twenty-one Mohave rattlesnakes, C. s. scutulatus were collected from Arizona and New Mexico. Venom proteomes were analyzed using RP-HPLC and SDS-PAGE. The toxicity of venoms was analyzed using LD50. Health severity outcomes between two Arizona counties, Pima and Cochise, were determined by retrospective chart review of the Arizona Poison and Drug Information Center database between 2002-2009. Main Results: Six phenotypes were identified based on three venom proteins; Mojave toxin, SVMP PI and PIII, and myotoxin. Venom changed geographically from SVMP-rich to Mojave toxin-rich phenotypes from south central to southeastern Arizona. Phenotypes containing myotoxins were only found in the transitional zone between the SVMP and Mojave toxin phenotypes. Venom samples containing the largest amounts of SVMP or Mojave toxin had highest and lowest LD50s, respectively. Conclusions: There was a significant difference when comparing the presence of CNS affects between Pima and Cochise counties (p = 0.001). No significant difference was found when comparing severity number of antivenom vials administered, days spent in a health care facility or envenomation per 100,000 population. Although not part of the original data to be collected, death and intubations, were also noted. There is a 10x and 50x increased risk of death or intubations if envenomated in Cochise County.
86

Caractérisation et complémentarité des facteurs de virulence du parasitoïde Hyposoter didymator (Ichneumonidae) / Characterization and complementarity of the virulence factors in the ichneumonid wasp Hyposoter didymator

Dorémus, Tristan 22 March 2013 (has links)
Les Hyménoptères parasitoïdes ont un développement larvaire s'effectuant au détriment d'un organisme hôte. Pour exploiter au mieux la ressource que représente un hôte arthropode dont la biologie peut présenter certains obstacles tels que la mobilité et le système immunitaire, les parasitoïdes ont développé une diversité modes de vie et de stratégies de virulence. Ce manuscrit replace les parasitoïdes dans leur contexte évolutif afin de mieux comprendre la diversité surprenante de leurs modes de vie. Ces modes de vie conditionnent la nature des interactions dans les systèmes hôte/parasitoïde. Nous verrons comment, par l'utilisation de nombreux facteurs de virulence tel que le venin, les polydnavirus et bien d'autres encore, les parasitoïdes manipulent la physiologie de leur hôte afin de le rendre adéquat à leur propre développement. Ce travail s'est intéressé au modèle endoparasitoïde Hyposoter didymator (Hym., Ichneumonidae). Nous avons ainsi caractérisé les protéines produites dans la glande à venin des femelles et identifié l'ensemble des gènes du polydnavirus associé (HdIV; H. didymator Ichnovirus), grâce à des techniques de protéomique, génomique et transcriptomique. Nous avons également suivi et quantifié les altérations de la physiologie de l'hôte Spodoptera frugiperda au cours du parasitisme et évalué le rôle relatif de différents facteurs dans ces perturbations et dans la réussite parasitaire. Nos résultats ont permis de montrer que seul le fluide du calice contenant HdIV est nécessaire au développement du parasitoïde. En parallèle, nous avons mis à jour une propriété immuno-évasive des œufs d'H. didymator liée à des protéines associées à l'exochorion. L'ensemble de ce travail a permis de dessiner un élégant schéma expliquant la complémentarité spatio-temporelle des facteurs de virulence durant le parasitisme. Finalement, nous avons cherché à mieux comprendre le déterminisme du spectre d'hôte d'H. didymator, ce qui nous a conduit à montrer que les deux stratégies de contournement de la réponse immunitaire (immuno-évasion et infection virale) se révèlent inefficaces chez les hôtes non-permissifs. / Parasitic wasps must deal with physiological features of their host such as mobility, an efficient immune system and a variable metabolism. To ensure successful parasitism in a large range of arthropod hosts, parasitoids display a huge diversity of lifestyle and rely in a variety of virulence factors. In this document, we introduce parasitoid lifestyle in an evolutionary context in order to better understand the parasitoid complexity. As the parasitoid lifestyle drives the host/parasitoid interaction outcome, we discuss for all how the virulence factors such as venom, polydnaviruses and many others are used to ensure successful development of the parasitoid. In this study, we focused on the endoparasitoid Hyposoter didymator (Hym., Ichneumonidae) virulence factors. We thus identified venom proteins and the genes from the associated polydnavirus, HdIV using proteomics, genomics and transcriptomics approaches. Studies on the effect of the venom and the calyx fluid containing the polydnavirus HdIV, reveal that only the calyx fluid is necessary for Spodoptera frugiperda host physiological alteration and parasitism success. Futhermore, this work presents the discovery of a local immune-evasive property of the H. didymator egg exochorion. All these data permitted us to design an effective spatio-temporal model of the virulence factor complementarity used by H. didymator during the parasitism time course. Finally, studies on the H. didymator host range reveals the inefficiency of the different virulence factors in non-permissive hosts, opening insights on the host permissiveness molecular mechanisms.
87

Etude toxinologique du venin de fourmis exotiques : identification et caractérisation d’un peptide antimicrobien / Study of exotic ants venoms : identification and characterization of an antimicrobial peptide

Rifflet, Aline 23 May 2012 (has links)
Les venins animaux, par leur richesse biochimique et la diversité de leurs cibles moléculaires, sont une source importante de molécules dont les applications potentielles sont nombreuses. La recherche de nouveaux médicaments pour remplacer certains antibiotiques devenus inefficaces face à l'apparition de résistances, est un axe fort de la recherche pharmacologique. Depuis plus de 40 ans, la découverte de toxines animales montre que les animaux venimeux peuvent être les « pharmaciens du futur ». Le venin de fourmis est encore peu étudié. Seul celui de quelques espèces a été exploré, avec à chaque fois la mise en évidence de toxines originales. L'objectif de cette thèse a été l'étude du venin de fourmis exotiques sur la base d'une approche pluridisciplinaire qui combine l'analyse biochimique et la toxinologie. Les travaux se sont articulés autour de deux axes principaux : (1) Recherche d'activités biologiques sur insectes et bactéries ; (2) Fractionnement des venins par des techniques séparatives et analyse biochimique des peptides isolés par spectrométrie de masse. Deux espèces de fourmis ont été choisies en fonction de leur mode de vie : Crematogaster striatula, une espèce arboricole et Tetramorium bicarinatum, une espèce terricole. Les différentes activités biologiques de leurs sécrétions venimeuses ont été conduites par test MTT. Le liquide de Dufour de C. striatula en plus de sa capacité à éloigner les espèces concurrentes montre une capacité à paralyser les termites de manière irréversible. Concernant le venin de T. bicarinatum, deux peptides ont été isolés et identifiés par spectrométrie de masse. La bicarinaline, peptide de 20 acides aminés et amidé à son extrémité C-terminale, s'est démarqué par son action antibactérienne à large spectre. Testée sur deux souches de staphylocoques, ce peptide se révèle aussi efficace voire plus puissant que la méllitine, peptide antimicrobien du venin d'abeille. La bicarinaline apparaît comme un candidat potentiel pour la conception de nouveaux traitements antibiotiques. / Animal venoms, by their biochemical richness and diversity of molecular targets, are a highly significant source of new molecules, with numerous potential applications. A major thrust of present pharmacological research now concerns drugs to replace certain antibiotics, proven ineffective due to the appearance of resistant strains. And discoveries of animal toxins over the past 40 years or more, have shown that venomous species could be the « pharmacists of the future », with only a few species of ants' venoms having been studied, but each time resulting in the description of original toxins. The aim of this thesis has been to study the venom of tropical ants using a multidisciplinary approach combining biochemical analysis and toxinology, centred on two main areas: (1) Research into their biological activity on insects and bacteria; (2) Fractionation of venoms using separative techniques, plus biochemical analysis of the peptides isolated using mass spectrometry. Two species of ant have been chosen based on their lifestyles: Crematogaster striatula is arboricolous and Tetramorium bicarinatum, terricolous, and the different biological activities of their crude venoms have been investigated using the MTT test. The Dufour liquid of C. striatula, in addition to its ability to scare away competitors, can definitively paralyse termites. For the venom of T. bicarinatum, two peptides have been isolated, and identified using mass spectrometry. Bicarinalin, a short 20 amino acid residues C-terminally amidated peptide, was notable for its wide spectrum antibacterial activity which, when tested on two Staphylococcus strains, proved to be at least if not more potent than mellitin, the antimicrobial peptide from bee venom. Bicarinalin would thus appear to be a good candidate for the development of new antibiotic drugs.
88

Isolamento e caracterização de serinopeptidases de Pseudechis australis / Isolation and characterization of serinopeptidases Pseudechis australis

Levindo, Samuel de Brito 16 September 2016 (has links)
Os venenos de serpentes peçonhentas representam uma mistura muito rica em compostos orgânicos e inorgânicos com potencial farmacológico, clínico e médico considerável. (As propriedades de seus componentes vêm sendo pesquisadas e características que antes não eram observáveis passam a ser descobertas influenciando à obtenção de novas drogas e na otimização de terapias já existentes. A maior parte dos compostos presentes nos venenos das serpentes é formada por proteínas que representam de 90 a 95% do peso seco do veneno, dentre elas destacam-se as peptidases (serino e metalopeptidases). As serinopeptidases caracterizam-se por apresentar no sítio ativo uma tríade catalítica idêntica a presente na tripsina, a qual é formada pelo agrupamento dos aminoácidos, His 57, Asp 102 e Ser 195. Constituem um grupo de enzimas que apresentam uma ampla variedade de efeitos biológicos, com massa molecular entre 25 kDa e 35 kDa, promovendo diversos efeitos fisiológicos como, alterações no sistema hemostático, agindo nos componentes da cascata de coagulação e com ação fibrinogenolítica. Ainda que já existam enzimas de veneno de serpentes com aplicação na regulação da cascata da coagulação, vários laboratórios têm buscado novas alternativas que apresentem atividade na hemostasia a fim de obtenção de produtos farmacológicos ainda não investigados. As serpentes australianas da família Elapidae, destacam-se para este fim, por apresentarem proteínas pró-coagulantes e até o momento não há descrição na literatura sobre a presença de serinopeptidases no veneno de Pseudechis australis. Neste trabalho conseguimos isolar e confirmar pela primeira vez a presença de uma serinopeptidase do veneno de Pseudechis australis através de técnicas cromatográficas e bioquímicas. Esta serinopeptidase possui atividade sobre a cadeia beta e alfa do fibrinogênio, não possui atividade gelatinolítica e possui semelhanças com o Fator X (FX) da cascata de coagulação. / Snake venoms represent a very rich mixture of organic and inorganic compounds with potential pharmacological, clinical and medical applications. This potential has not been fully exploited due to our incomplete knowledge of the properties of venoms and their components. Most of the compounds present in snake venoms are proteins that represent 90 to 95% of the dry weight, among which stand out peptidases (serine and metallopeptidases). The serinopeptidases are characterized by having a catalytic triad similar to the one present in trypsin, which is formed by, His 57, Asp 102 and Ser 195.These proteins constitute a group of enzymes that have a variety of activities, molecular mass between 25 kDa to 35 kDa, promoting many physiological effects as changes in the hemostatic system, acting on components of the clotting cascade and fibrinogenolytic action. Several snake venoms isolated peptidases are used for therapeutic purposes, among which serinopeptidases as Batroxobin® and Ancrod® used as anticoagulants in heart surgery. Pseudechis australis (King Brown or Mulga Snake) is a terrestrial species among the most poisonous of Australia and belonging to the family Elapidae which constitutes 57.7% of the snake species described in the Australian continent, Australian Elapidae are among the ten more toxic species in the world. Although there are already venom enzymes snakes with application in coagulopathies, several laboratories have sought alternatives for the treatment of hemostasic disorders in order to obtain new pharmacological products. Australian snakes from the Elapidae family, stand out for this purpose, because they have procoagulant proteins with properties similar to the macromolecular complex found in blood. It is worth noting that so far there is no description in the literature on the presence of serinopeptidases in Pseudechis australis venom and since serinopeptidases are closely linked to the hemostatic system, new serinopeptidases may have great potential in the development of drugs for the therapy of hemostatic disorders. In this work we managed to isolate and confirm the first time a serinopeptidase the Pseudechis australis venom through chromatographic and biochemical techniques. This serinopeptidase have activity on alpha and beta chain of fibrinogen, has no gelatinolytic activity and has similarities to factor X of the clotting cascade.
89

Purificação e caracterização de peptídeos presentes no veneno do escorpião Tityus serrulatus / Purification and characterization of peptides present in the Tityus serrulatus scorpion venom

Duzzi, Bruno 18 October 2018 (has links)
A cada dia os relatos sobre acidentes por escorpiões vêm aumentando no Brasil, com frequentes casos fatais. Dentre os escorpiões que compõem a fauna brasileira temos o Tityus serrulatus, considerado o mais perigoso por conta de sua facilidade adaptativa em centros urbanos e das manifestações clínicas severas em vítimas acidentadas, como febre, agitação psicomotora, hipertensão arterial seguida de hipotensão e edema pulmonar agudo. Dentre os componentes da peçonha se destacam os peptídeos estruturados por ligações dissulfeto, que são abundantemente relatados na literatura e atuam em canais de Na+ e K+. Ao contrário, os peptídeos lineares são pouco caracterizados. A partir desta premissa, nosso grupo identificou peptídeos lineares do veneno através de um screening empregando a enzima elastase. Esta enzima foi escolhida por estar envolvida em processos inflamatórios exacerbados, como em casos de edema pulmonar agudo, que é um dos principais sintomas do escorpionismo. Encontramos mais de 700 sequências peptídicas onde, através de um criterioso processo com o uso de bancos de dados de sequências depositadas e a literatura, selecionamos nove moléculas inéditas (TsP1 a TsP9) e duas já estudadas (hipotensinas I e II) para a síntese. Dentre estas moléculas, identificamos possíveis criptídeos advindos da Ts19 e moléculas com processamento diferenciado envolvendo a combinação de sequências peptídicas diferentes (peptídeos quiméricos), primeiramente relatadas e investigadas na peçonha do T. serrulatus neste trabalho. Além da elastase, utilizamos as enzimas de importância médica tripsina, ECA e NEP e os peptídeos sintéticos em nossos estudos, visando aumentar o conhecimento dos mecanismos moleculares envolvidos no escorpionismo e, também, com base no potencial biotecnológico de moléculas capazes de exercerem modulações das atividades destas peptidases. Destacaram-se peptídeos que podem ter ação em processos inflamatórios, uma vez que foram capazes de aumentar a atividade da elastase e tripsina, com destaque para o TsP5, que também apresentou citotoxidade intermediária. Alguns peptídeos aumentaram a atividade da ECA, sendo o peptídeo TsP2 capaz de potencializar a ação da bradicinina in vivo. A hipotensina I foi caracterizada como um inibidor não competitivo da NEP (Ki = 4,35 µM), podendo indicar a possível inibição desta metalopeptidase nos casos de hipotensão, onde a hipotensina I pode agir de forma sinérgica com o [des-Arg1]-Proctolin (Ki = 0,94 µM para a NEP), outro peptídeo linear do veneno caracterizado por nosso grupo. Os peptídeos não foram reconhecidos pelos soros antiescorpiônico e antiaracnídico produzidos pelo Instituto Butantan podendo indicar limitações na imunoterapia utilizada no tratamento das vítimas. Por fim, além dos novos peptídeos identificados, finalizamos a caracterização do FTR, um tripeptídeo que apresentou em nossos trabalhos anteriores propriedades antinociceptivas. No presente trabalho, demonstramos que este peptídeo é capaz de agir na via opioide, atuando em receptores delta de forma direta. Assim, com a identificação e caracterização destas moléculas conseguimos novos dados referentes a possíveis origens e processamento, ações tóxicas no envenenamento e potencial biotecnológico de alguns peptídeos lineares do T. serrulatus. / Reports of scorpions accidents with humans are increasing in Brazil, with some of the cases resulting in death. Among the scorpions from the Brazilian fauna, Tityus serrulatus is considered the most dangerous species, due to its easy adaptation in urban centers, and because it brings severe clinical manifestations in the victims, such as fever, psychomotor agitation, arterial hypertension followed by hypotension and acute pulmonary edema. Among the venom components that stand out are the peptides structured by disulfide bonds, which are richly reported in the literature and act on Na+ and K+ channels. In contrast, linear peptides are poorly characterized. From this evidence, our group identified linear peptides of the venom using the serine protease elastase screening. This enzyme was chosen because it is involved in inflammatory processes, such as cases of acute pulmonary edema, one of the main symptoms of scorpionism caused by T. serrulatus. More than 700 peptide sequences where found and, through a careful process using protein databases and the literature, from these all, we selected nine novel (TsP1 to TsP9) and two already characterized (hypotensins I and II) sequences for synthesis. Among these molecules, we identified possible cryptides derived from Ts19 and others molecules, with different processing involving combination of different peptide sequences (chimeric peptides), which are here firstly reported and investigated in the venom of T. serrulatus. In addition to elastase, we tested other enzymes of medical importance - trypsin, ACE and NEP - with the synthetic peptides, aiming to increase the knowledge of molecular mechanisms involved in scorpionism and also based on the biotechnological potential of peptidase-modulator molecules. Peptides that may have an action in inflammatory processes were highlighted, since they were able to increase the activity of elastase and trypsin, especially the TsP5, which also showed intermediate cytotoxicity. Some peptides increased the ACE activity, with the peptide TsP2 capable of potentializing the action of bradykinin in vivo. Hypotensin I was characterized as a noncompetitive inhibitor of NEP (Ki = 4.35 µM) and may indicate the possible inhibition of this metallopeptidase in cases of hypotension, where hypotensin I may act synergistically with [des-Arg1] - Proctolin (Kµ = 0.94 µM for NEP), a linear peptide present in the venom already characterized by our group. The peptides were not recognized by the antiscorpion and antiarachinid sera produced by the Butantan Institute and may indicate limitations in the immunotherapy. Finally, in addition to the new identified peptides, we concluded the in vivo characterization of FTR, a tripeptide that presented antinociceptive properties in our previous studies. In the present work, we demonstrate that this peptide is able to act in the opioid pathway, acting directly on delta receptors. Thus, with the identification and characterization of these molecules we obtained new data regarding possible origins and processing, toxic actions in the envenomation and biotechnological potential of some linear peptides of T. serrulatus venom.
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Estudo e caracterização bioquímica e biologíca do veneno da serpente Bothrops moojeni e mecanismo antiveneno do plasma desses animais. / Bothrops moojeni\'s snake venom and plasma anti-venom mechanisms: a biochemical and biological characterization.

Aguiar, Weslei da Silva 08 November 2016 (has links)
Foi observado no Laboratório de Herpetologia do Instituto Butantan que indivíduos da espécie Bothrops moojeni, quando acidentados entre si, apresentavam casos de mortalidade ocasionados por efeitos do envenenamento. Um modelo composto de análises bioquímicas e biológicas de 13 amostras de veneno e plasma de serpentes B. moojeni foi utilizado. SDS-PAGE mostrou perfis proteicos bem distintos para as amostras de veneno, e não para as de plasma. Western Blottings (WB) com amostras desses plasmas mostraram uma zona de detecção na faixa de 25 kDa em alguns indivíduos. Outro teste de WB, cruzando amostras de plasmas e venenos, mostrou que alguns indivíduos possuem proteínas que se ligam à estas regiões do plasma, o que não ocorre com o veneno dos outros indivíduos testados. Espectrometria de massas mostrou que esses indivíduos apresentam maiores concentrações proteicas e outras tantas exclusivas, incluindo inibidores de fosfolipases. A Dose Letal 50% mostrou uma maior eficiência nesses venenos, enquanto que a Dose Mínima Hemorrágica se mostrou inferior. Conclui-se que alguns indivíduos dessa espécie apresentam diferenças na composição dos seus venenos que se tornam significativas para o envenenamento. / It was observed in the Herpetology Laboratory of the Butantan Institute that individuals of the species Bothrops moojeni, when injured among themselves, presented cases of mortality caused by the effects of envenoming. A model composed of biochemical and biological analyzes of 13 venom and plasma samples of B. moojeni snakes was used. SDS-PAGE showed very different protein profiles for the venom samples, and not for the plasma ones. Western Blottings (WB) with samples of these plasmas showed a detection zone in the range of 25 kDa in some individuals. Another WB test, cross-linking plasma and venom samples, showed that some individuals have proteins that bind to these regions of the plasma, which does not occur with the venom of the other individuals tested. Mass spectrometry results showed that these individuals have higher protein and other unique concentrations, including phospholipase inhibitors. The Lethal Dose 50% showed a higher efficiency in these venoms, whereas the Minimum Hemorrhagic Dose was inferior. It is concluded that some individuals of this species present differences in the composition of their poisons that become significant for the envenoming process.

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