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1
Gracenea, Zugarramurdi Mercedes. « Contribución al conocimiento de determinados aspectos de la bionomia de Brachylaima ruminae Mas-Coma et Montoliu 1985 (Trematoda : Brachylaimidae) ». Doctoral thesis, Universitat de Barcelona, 1986. http://hdl.handle.net/10803/673000.
Texte intégralRésumé :
Los estudios que sobre ciclos biológicos de Tremátodos Digénidos de la familia Brachylaimidae Joyeux et Foley, 1930 se lleva a cabo desde hace ya años en el Departamento de Parasitología de la Facultad de Farmacia de la Universidad de Barcelona nos condujeron, en su día, al inicio del presente trabajo destinado a prestar una pequeña contribución al conocimiento de la bionomía de una especie concreta de Trematodo perteneciente a la familia anteriormente citada: Brachylaima ruminae Mas-Coma et Montoliu, 1985. El ciclo evolutivo de esta especie de Digénido ha sido dilucidado totalmente por MAS-COMA & MONTOLIU (1978 a, b) y MONTOLIU (1984) tanto en la Naturaleza como experimentalmente en el Laboratorio de nuestro Departamento. La complejidad de este ciclo triheteroxeno terrestre nos situó ante un amplio y atractivo abanico de posibilidades de estudio e investigación, dado que cada uno de los aspectos del ciclo es merecedor en sí mismo de un estudio en profundidad.
2
Pardini, Alessandra Xavier. « Utilização de preparações antigênicas de cisticercos de Taenia crassiceps para pesquisa de anticorpos na neurocisticercose (Taenia solium) ». Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/9/9136/tde-27012015-130517/.
Texte intégralRésumé :
O complexo teníase-cisticercose humana representa importante problema sócio-econômico e de Saúde Pública em países em desenvolvimento, incluindo nosso país. A forma mais grave da doença decorre da localização de cisticercos no Sistema Nervoso Central, a neurocisticercose. Devido à dificuldade de obtenção de parasitas a partir de suínos naturalmente infectados estudamos como fonte alternativa, preparações antigênicas de cisticercos de Taenia crassiceps (antígeno heterólogo), para pesquisa de anticorpos anti-cisticercos em líquido cefalorraquiano (LCR) de pacientes com neurocisticercose. Foram estudados os extratos antigênicos de líquido vesicular de cisticercos de Taenia crassiceps (LV-Tcra) e as frações purificadas por Concanavalina A (ConA-Tcra) obtida por coluna de afinidade com lectina e glicoprotéico fracionado (GP-Tcra) obtida a partir do antígeno LV-Tcra em eletroforese preparativa. Os antígenos LV-Tcra, ConA-Tcra e GP-Tcra para a detecção de anticorpos IgG anti-T. solium, foram ensaiados por ELISA em amostras de LCR e por imunoblot em amostras de LCR e soro. Foi utilizado também, kit comercial ELISA com antígeno de T. solium. A sensibilidade e a especificidade obtidas para os antígenos LV-Tcra, ConA-Tcra e GP-Tcra no teste ELISA foram de 100%, com boa reprodutibilidade. Os peptídeos em ordem de freqüência de reatividade para o antígeno LV-Tcra foram: 14-11kD (100%), 62kD (100%), 68kD (100%), 91kD (76%), 25kD (70%), 46KD (64%), 18kD (58%), 43kD (23%), 9-8kD (17%), 56kD (11%) e 32kD (11%). Para o antígeno ConA-Tcra foram identificados os peptídeos, por ordem de freqüência, 14kD (100%), 28kD (66%), 18kD (55%), 46kD (44%), 43kD (22%), 94kD (22%), 103kD (22%). Para o antígeno GP-Tcra, foram identificados somente os peptídeos de 14 - 18kD. Amostras de LCR de pacientes com esquistossomose não apresentaram reatividade com os extratos antigênicos e uma amostra de LCR de paciente com neurossífilis, apresentou forte reatividade eom os peptfdeos de baixo peso molecular≤20kD, para os três antígenos, inclusive no teste ELISA comercial com antígeno de T. solium. Os resultados confirmam que os antígenos de T. crassiceps são importantes fontes alternativas de extratos antigênieos. As frações glicoprotéicas mostraram-se eficientes na detecção de anticorpos anti-T. solium em amostras de LCR e soro de pacientes com neurocisticercose.The human taeniasis-cysticercosis complex represents an important socioeconomic and Public Health problem in developing countries, including Brazil. The most severe form of the disease is due to the localization of cysticerci in the Central Nervous System, i.e. neurocysticercosis. Due to the difficulty in obtaining parasites from naturally infected swine, we studied an alternative source consisting of Taenia crassiceps cysticerci (heterologous antigen) for the search of anti-cysticercus antibodies in cerebrospinal fluid (CSF) from patients with neurocysticercosis. We studied the antigenic extracts of vesicular fluid of Taenia crassiceps cysticerci (VF-Tcra) and the purified fractions Concanavalin A (ConA-Tcra) obtained from an affinity column with lectin and fractionated glycoprotein (GP-Tcra) obtained from the VF-Tcra antigen by preparative electrophoresis. The VF-Tcra, ConA-Tcra and GP-Tcra antigens for the detection of IgG antibodies were assayed by ELISA in CSF samples and by immunoblot in CSF and serum samples. A commercial ELISA kit with T. solium antigen was also used. The sensitivity and specificity obtained for the VF-Tcra, ConA-Tcra and GP-Tcra were 100% in the ELISA test, with good reproducibility. The peptides in order of frequency of reactivity with the VF-Tcra antigen were: 14-11kD (100%), 62kD (100%), 68kD (100%), 91kD (76%), 25kD (70%), 46KD (64%), 18kD (58%), 43kD (23%), 9-8kD (17%), 56kD (11%), and 32kD (11%). The following peptides, in order of frequency were identified for the ConA-Tcra antigen: 14kD (100%), 28kD (66%), 18kD (55%), 46kD (44%), 43kD (22%), 94kD (22%), and 103kD (22%). Only peptides of 14-18kD were identified for the GP-Tcra antigen. CSF samples from patients with schistosomiasis did not show reactivity with the antigenic extracts and a CSF sample from a patient with neurosyphilis presented strong reactivity with low molecular weight (≤20kD) peptides for the three antigens also in the commercial ELISA with the T. solium antigen. The results confirm that T. crassicepsantigens are important alternative sources of antigenic extracts. The glycoprotein fractions proved to be efficient in detecting anti-T solium antibodies in CSF and serum samples trom patients with neurocysticercosis.
3
Hofstatter, Bianca Delgado Menezes. « Avaliação de diferentes extratos enzimáticos fúngicos sobre ovos de Ancylostoma spp ». Universidade Federal de Pelotas, 2013. http://repositorio.ufpel.edu.br/handle/ri/2323.
Texte intégralRésumé :
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Previous issue date: 2013-02-28The role of companion animals or pets as zoonotic disease reservoirs has been recognized as a significant public health hazard throughout the world. Ancylostoma caninum and A. braziliense are zoonotic parasites which are transmitted to man through contact with soil contaminated with both eggs and larvae of these ancylostomids. The considerable prevalence of environmental contamination by Ancylostoma spp eggs, together with the difficulties of applying control measures and soil disinfection, as well as the development of resistance to anthelmintic therapy, highlights the need for alternative methods to help control these helminths. Taking into account that these nematodes spend part of their life cycle in the soil and that nematophagous fungi usually found in this ecosystem establish parasitic or predatory relationships with these parasites, thus playing an important role as natural enemies, the use of these agents in the effective control of nematodes is viable and desirable. Thus, nematophageous fungi can be used when the environment is already contaminated. This study aimed to determine helminth prevalence in dog feces collected on streets and parks in Pelotas County, Rio Grande do Sul State, Brazil, as well as to evaluate the in vitro ovicidal activity of different crude enzymatic extract preparations of CG193 and MICLAB 009 Paecilomyces lilacinus, MICLAB 008 Trichoderma virens and CG502 Trichoderma harzianum fungal isolates on Ancylostoma spp. eggs. Fifteen random feces samples were collected from 14 different places in town between January and March 2012, totaling 210 samples, which were submitted to coproparasitological tests. The fungal isolates evaluated were grown in minimum liquid medium under agitation at 28ºC for five days. Fungal preparations consisted of supernatant liquid medium without filtration (crude extract), filtered (filtered extract), macerated mycelium (crude macerate), and macerated mycelium submitted to filtration (filtered macerate). Ancylostoma spp. eggs were obtained from the feces of naturally parasitized dogs. In vitro assays consisted of four treatments and one control group. 4mL of each fungal extract was poured into Petri dishes added with a 1 mL suspension containing approximately 103 Ancylostoma spp. eggs. The control group consisted of 1mL suspension containing 1000 Ancylostoma spp. eggs added with 4mL sterile distilled water. All dishes were incubated at 25º C for 24 hours. Each assay had five replicates. Following, the total number of larvae present in each treatment and in the control group was counted. The results obtained showed that the overall prevalence of environmental contamination on public streets and parks was 57,6%, including both mono (67,8%) and multi (32,2%) infections. Ancylostoma spp. was the most frequent occurrence (88,4%), followed by Trichuris vulpis. (38,8%). When evaluating the in vitro ovicidal activity, the different fungal formulations tested for each fungus were found to differ (p<0,05) from the control group, showing a relevant ovicidal effect. When the egg hatching reduction percentage was calculated, the highest reduction occurred when the crude macerate preparation was used, showing 68,43% and 47,05% MICLAB 009 and CG193 P. lilacinus and 56,43% T. harzianum reduction percentages, respectively. The crude macerate reduction percentage for the T. virens isolate (52,25%) was slightly lower than that for the filtered macerate (53,64%). The finding that 88,4% of the feces were positive for Ancylostoma spp. eggs not only reveals the high environmental contamination rates in the municipality of Pelotas, but also warns of the urgent need to implement health education and responsible dog ownership programs, as well as the need to adopt additional control measures. The evaluation of the ovicidal activity showed that, regardless of the fungal extract tested, the fungus species evaluated were effective in reducing Ancylostoma spp. egg hatchability, and thus are potential candidates for the biological control of this nematodeThe role of companion animals as reservoirs of zoonotic diseases has been recognized as significant public health problem worldwide.
O papel dos animais de companhia como reservatórios de doenças zoonóticas tem sido reconhecido como significativo problema de saúde pública em todo o mundo. Ancylostoma caninum e A. braziliense são parasitos zoonóticos transmitidos ao homem pelo contato com solos contaminados com ovos e larvas destes ancilostomídeos. As consideráveis prevalências de contaminação ambiental por ovos de Ancylostoma spp., aliada as dificuldades de medidas de controle e desinfecção do solo, assim como o surgimento de resistência a terapia anti-helmíntica, evidenciam a necessidade de métodos alternativos que auxiliem no controle destes helmintos. Considerando-se o fato que os nematoides que infectam animais gastam parte do seu ciclo de vida no solo e que os fungos nematófagos, comumente encontrados nesse ecossistema, desenvolvem relações parasíticas ou predatórias com esses parasitos, desempenhando importante papel como inimigos naturais, torna-se viável e desejável o emprego destes agentes no controle eficaz de nematoides. Desta forma, os fungos nematófagos podem ser utilizados em situações em que o ambiente já está contaminado. Os objetivos do presente estudo foram verificar a prevalência de helmintos em fezes de cães coletadas em vias públicas do município de Pelotas, RS, Brasil, e avaliar a atividade ovicida in vitro de diferentes preparações de extratos brutos enzimáticos dos isolados fúngicos Paecilomyces lilacinus CG193, P. lilacinus MICLAB 009, Trichoderma virens MICLAB 008 e Trichoderma harzianum CG502 sobre ovos de Ancylostoma spp. No período de janeiro a março de 2012 foram coletadas aleatoriamente 15 amostras de fezes em 14 pontos do município, totalizando 210 amostras, as quais foram submetidas a exames coproparasitológicos. Os isolados fúngicos avaliados foram cultivados em meio mínimo líquido, em agitação, durante cinco dias a 28ºC. As preparações fúngicas consistiram do meio líquido sobrenadante sem filtração (extrato bruto) e filtrado (extrato filtrado), do micélio macerado (macerado bruto) e micélio macerado submetido a filtração (macerado filtrado). Os ovos de Ancylostoma spp. foram obtidos a partir de fezes de cães naturalmente parasitados. Os ensaios in vitro consistiram em quatro tratamentos e um grupo controle. Em placas de Petri foram vertidos 4mL de cada extrato fúngico e a esse volume foi acrescido 1mL de uma suspensão contendo aproximadamente 103 ovos de Ancylostoma spp. O grupo controle consistiu de 1mL de suspensão contendo 1000 ovos de Ancylostoma spp. acrescido de 4mL de água destilada estéril. Todas as placas foram incubadas a 25ºC, durante 24 horas. Cada ensaio foi constituído de cinco repetições. Após esse período, o número total de larvas presente em cada tratamento e no grupo controle foi contato. Os resultados obtidos demonstram que a prevalência geral de contaminação ambiental em vias públicas foi de 57,6% tanto em mono (67,8%) como em multi-infecções (32,2%). Ancylostoma spp. ocorreu em maior frequência (88,4%), seguido de Trichuris vulpis. (38,8%). Na avaliação da atividade ovicida in vitro foi observado que as diferentes formulações fúngicas testadas em cada fungo diferiram (p<0,05) do grupo controle, evidenciando relevante efeito ovicida. Quando calculado o percentual de redução de eclosão dos ovos, evidenciou-se que o maior valor de redução ocorreu quando utilizada a preparação macerado bruto, com percentuais de redução de 68,43% e 47,05% em P. lilacinus MICLAB009 e CG193, respectivamente, e 56,43% em T. harzianum. Apenas no isolado T. virens o percentual de redução do macerado bruto (52,25%) foi levemente inferior ao macerado filtrado (53,64%). O encontro de 88,4% de fezes positivas para ovos de Ancylostoma spp., além de evidenciar as altas taxas de contaminação ambiental no município de Pelotas, alertam para urgente implementação de programas de educação sanitária e de posse responsável dos cães, assim como para a necessidade da adoção de medidas complementares de controle. A avaliação da atividade ovicida mostrou que independente do extrato fúngico testado, as espécies de fungos avaliadas foram eficazes em reduzir a eclodibilidade de ovos de Ancylostoma spp. e, portanto, constituem-se em potenciais candidatos para o emprego no controle biológico deste nematoide.
4
Dallarés, Villar Sara Maria. « Twenty thousand parasites under the sea : a multidisciplinary approach to parasite communities of deep-dwelling fishes from the slopes of the Balearic Sea (NW Mediterranean) ». Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/402224.
Texte intégralRésumé :
El Mar Mediterráneo profundo permanece en gran parte inexplorado, y, específicamente, las comunidades parásitas de los peces mediterráneos de aguas profundas son mayormente desconocidas.
El principal objetivo de la presente tesis es caracterizar las comunidades parásitas de las importantes especies ícticas de aguas profundas siguientes: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) y Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Otro propósito importante es evaluar la respuesta de estas comunidades a gradientes y variables ambientales, a la dieta y a la ecología trófica de los hospedadores y su posible impacto en el estado de salud de estos últimos.
En los capítulos tercero a sexto se describen las comunidades parásitas de las especies mencionadas en diferentes estaciones, estratos de profundidad y localidades de las vertientes continental e insular del Mar Balear. Mientras que las comunidades parásitas de M. moro, P. blennoides y G. melastomus se caracterizaron por altos valores abundancia, riqueza y diversidad, las de S. canicula, E. spinax y C. coelolepis eran comparativamente más pobres y menos diversas. Diferencias ontogénicas, batimétricas, estacionales y geográficas se detectaron en las comunidades parásitas de las especies tratadas, en todos los casos asociadas a las dinámicas alimentarias (a su vez asociadas a la disponibilidad de presas a lo largo de los gradientes mencionados, en la mayoría de casos) de sus hospedadores. Se hallaron relaciones detalladas entre parásitos y presas ingeridas por los diferentes hospedadores, permitiendo confirmar las vías de transmisión ya conocidas para algunos parásitos y sugiriendo nuevas vías de infección para otros. La mayoría de parásitos se asociaron a altos niveles de O2 y turbidez del agua. Mientras que los primeros favorecen la abundancia de parásitos con ciclos indirectos como resultado de la proliferación del zooplancton y la agregación de hospedadores intermediarios potenciales asociada, los segundos favorecen la transmisión de parásitos y aumentan la carga parasitaria debido a un incremento del zooplancton y de las comunidades de invertebrados suprabentónicos a causa de una mayor disponibilidad de nutrientes. Altos niveles de salinidad del agua parecieron estar asociados a mayores abundancias de los nematodos Hysterothylacium aduncum y Proleptus obtusus, probablemente porque la salinidad se correlaciona con la abundancia de decápodos y misidáceos, entre otros, que son utilizados por esos nematodos como hospedadores intermediarios. A su vez, altos niveles de temperatura del agua se asociaron a la abundancia de parásitos monogeneos, probablemente debido a un mayor éxito de eclosión de los huevos y a una reducción del tiempo de maduración reproductiva a mayores temperaturas, como ya había sido demostrado para estos parásitos. Se detectaron una inhibición de la enzima acetilcolinesterasa y mayores niveles de peroxidación de lípidos, ambos posiblemente asociados a estrés por las infecciones parasitarias, en varias especies de peces. En general, la carga parasitaria no tuvo un impacto significativo en los índices de condición generales de los peces, ni en el número y/o área de centros macrofágicos o melanomacrofágicos esplénicos en el caso de teleósteos, o en el número de melanomacrófagos hepáticos en el caso de G. melastomus.
En el séptimo capítulo se aportan datos morfológicos, moleculares y ecológicos de diferentes estadíos de desarrollo del cestodo Ditrachybothridium macrocephalum en su hospedador definitivo, G. melastomus, y en el Mar Mediterráneo por primera vez.
En el octavo capítulo la familia de cestodos Sphyriocephalidae es revisada. Se describe la nueva especie Heterosphyriocephalus encarnae n. sp., y dos especies ya existentes, Sphyriocephalus viridis y Sphyriocephalus tergestinus, se redescriben a partir de datos morfológicos y moleculares de nuevo material recolectado y de material de museo.The Mediterranean deep-sea remains mostly unexplored and, specifically, the parasite communities of Mediterranean deep-dwelling fishes are largely unknown. The central purpose of the present thesis is to characterize the parasite communities infecting the following important deep-dwelling ichthyc species in the Balearic Sea: Mora moro (Risso, 1810), Phycis blennoides (Brünnich, 1768), Galeus melastomus Rafinesque, 1810, Scyliorhinus canicula (Linnaeus, 1758), Etmopterus spinax (Linnaeus, 1758) and Centroscymnus coelolepis Barbosa du Bocage and de Brito Capello, 1864. Another main objective is to assess the responsiveness of these parasite communities to environmental gradients and variables, to host diet and trophic ecology and their possible impact on host health condition. In the third to sixth chapters, the parasite communities of the mentioned species are described on different seasons, depth strata and localities from the mainland and insular slopes of the Balearic Sea. While parasite communities of M. moro, P. blennoides and G. melastomus were characterized by high abundance, richness and diversity values, those of S. canicula, E. spinax and C. coelolepis were comparatively poorer and less diverse. Ontogenic, bathymetric, seasonal and geographic differences in the parasite communities of the different species addressed were detected, in all cases linked to the feeding dynamics (in turn linked to prey availability across the mentioned gradients, in most cases) of their hosts. Detailed relationships were found between parasite taxa and prey ingested by the different hosts, allowing confirmation of the transmission pathways known for some parasites and suggesting new ways of infection in others. Most parasites were linked to high O2 and turbidity levels. While the former enhances the abundance of parasites with indirect life cycles as a result of zooplankton proliferation and the associated aggregation of potential intermediate hosts, the latter favours parasite transmission and increases parasite loads due to an increase of zooplankton and suprabenthic invertebrate communities linked to higher nutrient availability. High water salinity levels seemed to be linked to higher abundance of the nematodes Hysterothylacium aduncum and Proleptus obtusus, probably because salinity correlates with the abundance of decapods and mysids, among others, which are used by these nematodes as intermediate hosts. In turn, high water temperature levels correlated with the abundance of monogenean parasites, likely due to enhanced egg hatching success and reduced time to maturity, as previously reported for these parasites. An inhibition of acetylcholinesterase activity and increased lipid peroxidation levels were detected in different fish species, possibly associated to infection-related stress. In general, parasite burden did not have a significant effect on fish general condition indices or on the number and/or surface of splenic melano-macrophage or macrophage centres in the case of teleosts, or on the number of hepatic melano-macrophages in the case of G. melastomus. In the seventh chapter, morphological, molecular and ecological data of different developmental stages of the cestode Ditrachybothridium macrocephalum are provided for the first time from its definitive host, G. melastomus, in the Mediterranean Sea. In the eighth chapter, the cestode family Sphyriocephalidae is revised. The new species Heterosphyriocephalus encarnae n. sp. is described, and two already existing species, Sphyriocephalus viridis and Sphyriocephalus tergestinus are further redescribed based on morphological and molecular data of newly-collected and museum material.
5
Pérez, García David. « A journey to the deeps of the sea : parasite communities of the Alepocephalidae and the Macrouridae in the Balearic Sea (NW Mediterranean) ». Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/402267.
Texte intégralRésumé :
Tot i el gran nombre d’estudis del mar Mediterrani, el seu mar profund segueix sent en gran part desconegut, especialment en relació a la seva fauna parasitària. Els paràsits són components importants dels ecosistemes. Al trobar-se al llarg de la xarxa tròfica, aquests poden aportar informació sobre el seu hoste. També és d’esperar que l’hoste respongui als efectes perjudicials dels paràsits a diferents nivells. A més a més, les alteracions cito-histològiques i/o les variacions de certs marcadors bioquímics poden ser relacionades amb la presència de paràsits i ser útils per avaluar la salut dels peixos. Com la majoria dels peixos del Mediterrani profund són encara en gran part desconeguts, els seus paràsits poden ser valuoses fonts d’informació. Alepocephalus rostratus i els Macrouridae són components importants de les comunitats íctiques del talús profund del mar Balear. Per aquest motiu, l’objectiu de la present tesi és caracteritzar per primer cop les comunitats de paràsits d’Alepocephalus rostratus i dels macrúrids Coelorinchus caelorhincus, Coelorinchus mediterraneus, Coryphaenoides guentheri i Coryphaenoides mediterraneus, i estudiar la seva variabilitat natural i el seu efecte sobre la salut dels peixos en el mar Balear. A més a més, es discutiran la relacions entre el perfil tròfic dels hostes i les comunitats parasítiques. Les comunitats de paràsits de A. rostratus estaven constituïdes per un baix nombre d’espècies (set espècies de metazous i un coccidi). Una baixa riquesa conjuntament amb una alta proporció de formes larvàries dels paràsits és normalment característic de peixos meso- i batipelàgics. Això és deu probablement a la dieta especialitzada d’A. Rostratus en organismes planctònics. Les espècies predominants van ser les larves de Tetraphyllidea i de nematodes cucullànids. L’activitat de acetilcolinesterassa estava positivament relacionada amb l’abundància de Tetraphyllidea fam. gen. sp., Anisakis physeteris i H. aduncum i negativament amb la de Cucullaninae gen. sp. L’activitat de lactat deshidrogenassa va mostrar una relació positiva amb l’abundància dels paràsits Paracyclocotyla cherbonnieri i Tetraphyllidea fam. gen. sp. Es van detectar coccidis als cecs pilòrics amb una prevalença del 90% a Barcelona. Un total de 11 taxons van ser trobats als quatre macrúrids estudiats, sent el copèpode Hamaticolax resupinus l’únic paràsit comú entre tots ells. Coelorinchus mediterraneus, C. guentheri i Cor. mediterraneus van exhibir unes comunitats de paràsits bastant homogènies, especialment en els últims dos peixos, segurament per la seva similar dieta. Coelorinchus mediterraneus va tenir la major riquesa de taxons paràsits (vuit espècies), mentre que C. guentheri i Cor. mediterraneus en van tenir cinc i sis, respectivament, i C. caelorhincus tres. Gran part dels paràsits van ocórrer en baixa prevalença (<10%), mentre que només tres espècies van ser excepcionalment prevalents i abundants: les larves de Cucullanidae fam. gen. sp. en C. caelorhincus; Lepidapedon desclersae en Coe. mediterraneus i Hysterothylacium aduncum en ambdues espècies de Coryphaenoides. Pocs efectes en la salut dels peixos van quedar reflectits a nivell enzimàtic i histopatològic, probablement per la poca càrrega parasitària en els hostes. Hamaticolax resupinus n. sp. és descrit per primer cop en Coe. mediterraneus i Cor. mediterraneus. És la segona espècie d’Hamaticolax que es troba en macrúrids i és el Bomolochidae trobat a major profunditat a nivell mundial. Hamaticolax resupinus n. sp. és molt similar a H. maleus Oldewage, 1994, però es diferencia d’aquest, entre d’altres, per tenir una mida del cos més petita. Raphidascaris (R.) macrouri n. sp. és descrit per primer cop en els macrúrids del mediterrani profund Nezumia aequalis i Trachyrincus scabrus. Aquesta espècie es diferencia de la resta del subgènere pel seu gran nombre de papil·les caudals i espícules curtes.Despite the great number of studies on the Mediterranean, its deep sea remains largely unknown, especially in relation to its parasite fauna. Parasites are important components of ecosystems. Being ubiquitous throughout all food webs, they can provide significant information of their hosts. In addition, it is expected that host respond to the harmful effects of parasites at different levels. Moreover, histo-cytological alterations and/or variations on the levels of certain biochemical markers can be related to the presence of parasites and are means to evaluate fish health. Since most of the important deep Mediterranean fishes are still largely unknown, their parasites can prove to be valuable sources of information. Alepocephalus rostratus and Macrouridae are important components of the fish community along the deep slope of the Balearic Sea. For this reason, the objectives of the present thesis are to characterize for the first time the parasite communities of Alepocephalus rostratus, and the macrourids Coelorinchus caelorhincus, Coelorinchus mediterraneus, Coryphaenoides guentheri and Coryphaenoides mediterraneus, their natural variability and their effects on fish health in the Balearic Sea. In addition, the relationship between the trophic profile of hosts and parasite communities will be discussed. The parasite communities of A. rostratus were constituted by little number of species (seven metazoan species and one coccidian). Low richness together with the high proportion of parasite larval forms are usually characteristic of meso- and bathypelagic fish species. This is probably due to the specialized diet of A. rostratus on planktonic organisms. The larval tetraphyllideans and cucullanid nematodes were the predominant species. A positive relationship was found between acetylcholinesterase activity and Tetraphyllidea fam. gen. sp., Anisakis physeteris and H. aduncum abundance and a negative one with the abundance of Cucullaninae gen. sp. Lactate dehydrogenase showed a positive relationship with the abundance of the parasites Paracyclocotyla cherbonnieri and Tetraphyllidea fam. gen. sp. Coccidians were detected in the pyloric caeca with a prevalence of 90% in Barcelona. A total of 11 parasite taxa were found among the four macrourids studied, being the copepod Hamaticolax resupinus the only parasite shared by all of them. Coelorinchus mediterraneus, C. guentheri and Cor. mediterraneus exhibited rather homogeneous parasite communities, especially in the case of the latter two, probably due to their similar diet composition. Coelorinchus mediterraneus showed the highest richness of parasite taxa (eight species), whereas C. guentheri and Cor. mediterraneus harboured up to five and six, respectively, and C. caelorhincus up to three. Several of the encountered parasites occurred at very low prevalence (<10%), while only three species were exceptionally prevalent and abundant: Cucullanidae fam. gen. sp. larvae in C. caelorhincus; Lepidapedon desclersae in Coe. mediterraneus and Hysterothylacium aduncum in both Coryphaenoides spp. Few parasite effects on fish health were reflected at enzymatic and histological level, probably due to the low parasite burden in their hosts. Hamaticolax resupinus n. sp. is described for the first time from Coe. mediterraneus and Cor. mediterraneus. It is the second Hamaticolax species that parasitizes a macrourid species and it is the deepest bomolochid encountered worldwide. Hamaticolax resupinus is smaller than its closely related species H. maleus, females have wider genital double-somite markedly wider than free abdominal somites and with convex lateral margins. Raphidascaris (R.) macrouri n. sp. is described for the first time from the deep Mediterranean macrourids Nezumia aequalis and Trachyrincus scabrus. This species differentiates from the rest of the subgenus by having high number of caudal papillae and short spicules.
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Dhorda, Mehul. « Molecular parasitology and diagnosis of Malaria in pregnancy ». Paris 6, 2010. http://www.theses.fr/2010PA066405.
Texte intégralRésumé :
Le paludisme reste la maladie parasitaire la plus répandue au monde dont les effets néfastes sont particulièrement sévères chez les enfants et les femmes enceintes. La morbidité liée au paludisme pendant la grossesse (PpG) prend souvent la forme d’une séquestration parasitaire dans le placenta, d’une anémie chez la femme et chez le nouveau-né et d’une réduction du poids de l’enfant à la naissance. L’ensemble de ces facteurs augmente le risque de la mortalité maternelle, fœtale et néonatale. Il y a un besoin urgent d’améliorer la prise en charge du PpG à savoir le traitement, le diagnostic et la prophylaxie contre cette maladie. Les traitements antipaludiques actuellement recommandés pour les femmes dans le 2e ou 3e trimestre de leur grossesse sont les combinaisons thérapeutiques à base d’artémisinine (CTA). Les données actuelles sur ces médicaments concernent seulement environ 1500 femmes, principalement non-afriquaines. Des études rigoureuses sur l’utilisation de la combinaison artémether-luméfantrine (AL, Coartem®) chez les femmes enceintes Africaines n’ont pas encore été réalisées. De plus, la connaissance de la pharmacocinétique de ces médicaments, altérée chez les femmes enceintes, reste très limitée. Les CTAs sont supposées être utilisées une fois que l’infection a été mise en évidence par un test de diagnostic. La goutte épaisse est le moyen de diagnostic du PpG le plus souvent utilisé, mais cet outil n’est pas le mieux adapté à cette utilisation puisque les infections séquestrées placentaires peuvent rester indécelables dans le sang périphérique. Des tests rapides de diagnostic (TDR), où des protéines parasitaires dénommées HRP2 qui circulent dans le sang sont décelées par immuno-chromatographie, pourraient combler cette lacune. Les TDRs à l’HRP2 semblent pouvoir détecter des infections en dessous du seuil de détection microscopique, mais ceci n’a été démontré qu’au moment de l’accouchement. Leur utilité lors des dépistages effectués pendant la grossesse n’a pas été encore été évaluée. Enfin, il n’existe que très peu de données sur la dynamique de l’infection palustre durant la grossesse. OBJECTIFS : (1) Évaluer l’efficacité et l’innocuité de la CTA Coartem vs. Quinine dans le traitement du paludisme simple chez les femmes enceintes durant le 2e ou 3e trimestre de grossesse ; (2) Évaluer la sensibilité et la spécificité de la gouttes épaisses vs. Le TDR à l’HRP2 pour la détection des infections parasitaires pendant la grossesse ; (3) Obtenir des données sur l’histoire naturelle des infections palustres durant la grossesse, en se basant sur l’analyse moléculaires de parasites. MÉTHODES : Cette série d’études a été réalisée à Mbarara, une ville d’environ 70,000 habitants dans le sud-ouest de l’Ouganda. Mille deux cent vingt-neuf femmes enceintes ont été incluses dans la cohorte dite « MIP ». Chacune a été dépistée avec un TDR à l’inclusion dans la cohorte. Trois cent quatre femmes dans le 2e ou le 3e trimestre de leur grossesse qui ont été diagnostiquées avec le paludisme par goutte épaisse ont été invitées à participer à un essai clinique randomisé de non-infériorité de Coartem, une CTA composée de l’artémether et de la luméfantrine, et de la quinine par voie orale. Ces 304 femmes ont été suivies hebdomadairement jusqu'à l’accouchement. Les taux de guérison à J42 et/ou à l’accouchement ont été confirmés par génotypage des parasites par PCR. Les effets secondaires des médicaments, l’issue de la grossesse, la croissance et le développement du nouveau-né jusqu'à un an de vie ont été analysés. Pour l’évaluation des tests diagnostiques, les ultimes 103 femmes recrutées dans la cohorte MIP ont été suivies hebdomadairement (les femmes de l’essai clinique) ou mensuellement (les femmes de la cohorte MIP). A chaque visite de suivi, du sang capillaire ou veineux a été prélevé pour préparer des gouttes épaisses et des frottis, pour effectuer un TDR à l’HRP2 (Paracheck Pf®), et enfin pour des études moléculaires dont un dépistage des 4 espèces de Plasmodium qui infectent l’Homme par PCR. Les indicateurs standard des tests de diagnostic ont été calculés pour les gouttes épaisses et pour les TDRs en considérant les résultats de l’analyse PCR comme « gold standard ». Pour le suivi des femmes afin de décrire l’évolution de l’infection parasitaire post-traitement ou le long de la grossesse, les échantillons prélevés aux visites hebdomadaires ont aussi été testés pour Plasmodium par PCR, et les infections au P. Falciparum ont été caractérisées par le génotypage de 3 marqueurs parasitaires polymorphes : glurp, msp2, et msp1. RESULTATS : 304 femmes (152 dans chaque bras) ont été enregistrées dans l’étude thérapeutique. Les taux de guérison avec les deux médicaments étaient élevés : 99. 3% (96. 0—99. 9) pour le Coartem à J42 et 98. 2% (93. 8—99. 8) à l’accouchement. Pour la quinine, les chiffres correspondant étaient aussi élevés : 97. 6% (93. 1-99. 5) à J42 et 96. 1% (90. 4-98. 9) à l’accouchement. Donc l’efficacité du Coartem n’était pas inférieure à celle de la quinine. Aucun effet secondaire sévère n’a été enregistré chez les patients traités par le Coartem. Les effets indésirables de la quinine ont conduit à l’arrêt du traitement dans 4 cas. L’issue des grossesses était similaire dans les deux bras. Les résultats de 299 visites/échantillons furent analysables dans l’évaluation des tests diagnostiques. La PCR a détecté 23 infections de P. Falciparum, alors que la goutte épaisse n’en a détecté que 7 et le TDR à l’HRP2 seulement 6, La sensibilité des tests était de 30. 4% (95%CI 14. 1—53. 0) et de 26. 1% (95%CI 11. 1—48. 7) ; la spécificité de la goutte épaisse était de 99. 64% et des TDRs, de 100%. Des échantillons prélevés de 35 femmes qui ont reçu un traitement antipaludéen ont été analysés. Les résultats de ces analyses ont révélé la complexité et la variabilité des infections post-traitement. Trois cas de P. Vivax chez des femmes enceintes ont été confirmés, et une analyse de la séquence du gène de la dihydrofolate reductase a indiqué que certains de ses parasites avaient acquis des mutations liées à la résistance à la pyrimethamine. DISCUSSION & CONCLUSIONS : L’efficacité et l’innocuité d’un traitement avec du Coartem (comparable à celui obtenu avec la quinine) amène des nouvelles données rassurantes quant au choix de drogues du type CTA pour le traitement du paludisme chez les femmes enceintes. La sensibilité des TDRs était moindre que celle attendue, mais ceci pourrait être du au type d’analyse possibles dans le cadre de notre suivi. De études qui évalueraient l’utilité des TDRs en prenant en compte des traitements antipaludiques donnés aux femmes enceintes, seraient à prévoir. Une dynamique compliquée des infections palustres, souvent chroniques et non décelées par microscopie, a été observée au fil du temps après traitement. Enfin il a été démontré qu’une transmission stable de P. Vivax, un parasite auparavant considéré comme étant très rare Afrique sub-Saharienne, peut être maintenue malgré une haute prévalence de personne Duffy négative.
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Amorim, Jandui Almeida [UNESP]. « Levantamento de sarcofagídeos(Diptera) do Brasil incluindo a caracterização molecular de Peckia (Pattonella) intermutans (Walker) ». Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/87797.
Texte intégralRésumé :
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amorim_ja_me_botib.pdf: 950896 bytes, checksum: 510efe38e747c38b3b0503fe22f6fe0a (MD5)Tendo em vista a grande similaridade interespecífica, a identificação de muitos sarcofagídeos usando os caracteres morfológicos é complicada e, sob este aspecto, o desenvolvimento e a aplicação de ferramentas moleculares se mostram cada vez mais necessários à resolução taxonômica e sistemática de diversas espécies. Os dípteros da família Sarcophagidae, especialmente os de hábito necrófilo, têm recebido destaque no campo forense devido à constância com que são encontrados associados a cadáveres, podendo contribuir de forma relevante na estimativa do intervalo pós-morte (IPM), descoberta do local e causa da morte, entre outros. No entanto, para que os espécimes coletados sejam usados de forma apropriada na obtenção de informações para auxiliar o trabalho de perícia, é primordial a identificação correta dos organismos, já que o IPM pode ser calculado com base na taxa de desenvolvimento que varia entre as diferentes espécies. Neste estudo, 194 espécies pertencentes à subfamília Sarcophaginae (Diptera), incluídas em 30 gêneros, são listadas levando em conta suas respectivas distribuições geográficas registradas no território brasileiro. Os gêneros que apresentaram uma grande diversidade de espécies foram Oxysarcodexia (24,7%), Lepidodexia (10,9%), Peckia (10,3%) e Dexosarcophaga (8%). Oxysarcodexia amorosa, O. thornax, Peckia (Euboettcheria) collusor, Peckia (Pattonella) intermutans e Sarcodexia lambens são encontradas na maioria dos estados brasileiros. No arquipélago de Fernando de Noronha, além de Nephochaetopteryx calida, que não apresenta até o momento registro de ocorrência para as localidades continentais, foram encontradas espécies de ampla distribuição no Brasil: O.thornax, (Peckia) chrysostoma e Tricharae (Sarcophagula) occidua. Adicionalmente, a análise da variabilidade genética entre representantes de populações de Peckia...
Due to high interspecific similarity, the identification of many sarcophagids by morphological characters is complicated and, in this way, the development and application of molecular tools have been required to address taxonomic and systematic species. The flies of the Sarcophagidae family, especially necrophagous species, have received attention in the forensic field because of the frequence with which they are found associated with cadavers, thus may contribute to estimate the post-mortem interval (:eMI), the discovery of place and cause of death, among other. However, for the specimens collected are used properly in obtaining information to assist the investigation, the correct identification of species is essential, since the PMI can based on the development rate that varies among different species. In this study, 194 species belonging to the Sarcophaginae subtribe (Diptera), included in 30 genus, are listed taking into account their geographic distribution throughout the Brazilian territory. The genus that showed a great species diversity were: Oxysarcodexia (24.7%), Lepidodexia (10.9%), Peckia (10.3%) and Dexosarcophaga (8%). Oxysarcodexia amorosa, 0. thornax, Peckia (Euboettcheria) collusor, Peckia (Pattonella) intermutans and Sarcodexia lambens are found in most Brazilian states, and only 3 of these were recorded in Fernando de Noronha archipelago, including Nephochaetopteryx calida, which until now has no record of occurrence for continental locations. Furthermore, genetic variability analysis among population of Peckia (Pattonella) intermutans (Walker) from Campinas, Jundiai, Mogi Guayu, Ubatuba (all cities located in Sao Paulo State) and Salvador (Bahia State) were performed based on sequences of carboxy-terminal region of the Cytochrome Oxidase I (COl) mitochondrial gene. This latter approach may help to validate a methodology for molecular identification of species... (Complete abstract click electronic access below)
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Pedrassani, Daniela [UNESP]. « Aspectos morfológicos, imunológicos e epidemiológicos do Dioctophyme renale em cães no Distrito de São Cristóvão, Três Barras, Santa Catarina ». Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/103838.
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pedrassani_d_dr_jabo.pdf: 2839127 bytes, checksum: e29898c79545e32be78e2f67b76b1d9d (MD5)Universidade do Contestado-Campus Canoinhas
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Pedrassani, Daniela. « Aspectos morfológicos, imunológicos e epidemiológicos do Dioctophyme renale em cães no Distrito de São Cristóvão, Três Barras, Santa Catarina / ». Jaboticabal : [s.n.], 2009. http://hdl.handle.net/11449/103838.
Texte intégralRésumé :
Orientador: Adjair Antônio do NascimentoBanca: Milton Hissashi Yamamura
Banca: Alessandro Francisco Talamini do Amarante
Banca: Vanete Thomaz Soccol
Banca: Rosangela Zacarias Machado
Não disponível.
Not available.
Doutor
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Gállego, Culleré M. (Montserrat). « Contribución al conocimiento de la acarofauna de los micromamíferos de la región catalana ». Doctoral thesis, Universitat de Barcelona, 1986. http://hdl.handle.net/10803/672995.
Texte intégralRésumé :
El desconocimiento generalizado de nuestra base de trabajo, la acarofauna, conlleva que, como paso previo a cualquier otro estudio, deba procederse primariamente a la tarea mucho más ingrata, y a veces poco reconocida, de realización de estudios faunísticos que son un medio indispensable para que la investigación acarológica pueda llevarse a cabo. Los estudios taxonómicos son otro paso necesario y obligado, tanto para la descripción de nuevas como para las deducciones filogenético-evolutivas que de las mismas puedan derivarse, dada la estrecha relación entre la especificidad de un parásito y su permanencia en un tipo determinado de hospedador.
En definitiva, el trabajo que se presenta se planteó con los siguientes objetivos: 1) Realización de estudios taxonómicos, tanto morfológicos como de variabilidad, de las especies insuficientemente conocidas, así como la descripción de aquellas nuevas especies que se han encontrado. 2) Ampliar los conocimientos faunísticos y geográficos de la acarofauna de los micromamíferos de la región catalana. 3) Estudiar las interacciones de la parasitocenosis acarina en dichos micromamíferos.
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Katagiri, Satie [UNESP]. « Avaliação de duas técnicas coproparasitológicas convencionais e de um kit comercial na investigação da epidemiologia de parasitas gastrintestinais de cães no Estado de São Paulo ». Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/89304.
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katagiri_s_me_botfmvz.pdf: 167133 bytes, checksum: ef0b4cbbb690eba49ecb859a6ee7a778 (MD5)Universidade Estadual Paulista (UNESP)
As técnicas coproparasitológicas de concentração por sedimentação e por flutuação e o kit TF-Test® foram utilizadas na investigação da epidemiologia dos parasitas gastrintestinais de cães no Estado de São Paulo. Amostras de fezes de 129 cães errantes e de 125 domiciliados foram colhidas de outubro de 2004 a setembro de 2005 e processadas de acordo com os protocolos do kit TF Test® e dos métodos de centrífugo-sedimentação e centrífugo-flutuação. Os seguintes parasitas e suas respectivas freqüências foram detectados: Ancylostoma spp. (38,2%), Giardia sp. (16,9%), Toxocara canis (8,7%), Tnchuns vulpis (7,1%), Isospora spp. (3,5%), Sarcocystís spp. (2,7%) e Dipy!idium caninum (2,4%). Dos 132 animais parasitados, 79 apresentaram parasitismo único e 53 estavam parasitados por dois ou mais gêneros e/ou espécies. Em cães errantes a prevalência de Ancylostoma spp., T. canis e Giardia sp. e a ocorrência de poliparasitismo foi maior (P < 0,01) que em animais domiciliados. Não houve diferença na freqüência de parasitas intestinais relacionada ao sexo, raça ou ao tratamento anti-helmíntico dos animais (P > 0,05), no entanto a freqüência de T. canis foi maior (P < 0,05) em cães jovens. Com relação à sazonalidade, a detecção de cistos de Giardia sp. foi mais freqüente nos meses de outubro a março. A sensibilidade diagnóstica do método de centrífugo-flutuação foi maior para todos os parasitas intestinais diagnosticados, porém somente no caso de Ancylostoma spp. essa diferença (P <0,05) se expressou em termos de uma maior freqüência de detecção de cães infectados. O elenco de parasitas diagnosticados na região estudada faz com que a técnica de centrifugo-flutuação com sulfato de zinco seja a mais apropriada tanto para os estudos epidemiológicos como para o diagnóstico individual, especialmente nas infecções subclínicas.
The sedimentation and flotation procedures for concentration of fecal specimens and the commercial device TF were used, in an epidemiological investigation of gastrointestinal parasites of dogs in São Paulo state. Fecal samples from 129 stray dogs and 125 dogs with an owner were collected from October 2004 to September 2005. AlI samples were concentrated by the sedimentation and flotation methods and by TF-Test® device. The following parasites, and their respective frequency were diagnosed in fecal samples : Ancylostoma spp. (38,2%), Giardia sp. (16,9%), Toxocara canis (8,7%), Tnchuris vulpis (7,1%), Isospora spp. (3,5%), Sarcocystis spp. (2,7%) and Dipylidium caninum (2,4%). Fifty-three out of 132 infected animais had mixed infection with two or more parasite genera. The prevalence of Ancy!ostoma spp., 1 canis and Giardia sp. as well as the occurrence of mixed infections were significantly higher in stray dogs (P <0,01) than in dogs with an owner. No effect of gender, breed and anti-helminthic treatment (P> 0,05) on the parasite frequency was observed, but the frequency of T. canis was higher (P < 0,05) in young animais. Giardia sp. cysts were more frequently detected from October to March. The centrifugation-flotation method was generally more accurate in the diagnosis of ali intestinal parasites of dogs, but only for Ancylostoma spp. this difference was observed in terms of prevalence. The species of parasites found in the studied region make the zinc sulfate flotation the most appropriate method not only to epidemiological studies, but also to individual diagnosis, speciaily in subciinical infections.
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Nagata, Walter Bertequini. « Validação da técnica TF-Test Coccidia para detecção de Cryptosporidium spp. e Giardia spp. em crianças de pré-escola e seus respectivos cães (Canis familiaris) / ». Araçatuba, 2019. http://hdl.handle.net/11449/183347.
Texte intégralRésumé :
Orientador: Sílvia Helena Venturoli PerriResumo: A criptosporidiose e a giardíase são doenças gastrointestinais, com distribuição cosmopolita, causada, respectivamente, por um protozoário coccídio intracelular obrigatório e um parasito flagelado, que pode afetar humanos e animais. O objetivo neste projeto foi detectar por meio da técnica TF-Test Coccidia e pela reação em cadeia da polimerase (RCP), a ocorrência do Cryptosporidium spp. e a Giardia spp. em crianças de pré-escola e seus respectivos cães (Canis familiaris) do Município de Araçatuba, São Paulo, de maneira inédita. Para a identificação dos oocistos do parasito supramencionado foi empregada a nova técnica parasitológica TF-Test Coccidia e RCP. A partir da análise destas amostras, verificou-se que 35,00% (35/100) das crianças estavam infectadas por alguma espécie de parasito intestinal, sendo que 5,00% eram positivas microscopicamente para Cryptosporidium spp. e 30,00% para Giardia spp. Nos cães, 3,13% (1/32) foram considerados positivos para Giardia spp., embora nenhum animal apresentasse oocisto de Cryptosporidium spp. nas fezes. Pela PCR 3,00% das crianças foram positivas para Cryptosporidium spp. e 35,00% para Giardia spp.. Enquanto que para os cães, pela mesma técnica molecular, nenhum animal foi considerado positivo para Cryptosporidium spp. e apenas 6,25% foram positivos para Giardia spp.. Dessa forma, foi verificado que a técnica parasitológica TF-Test Coccidia apresentou boa concentração e morfologia dos parasitos encontrados, com baixa quantidade de debri... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Cryptosporidiosis and giardiasis are gastrointestinal diseases with cosmopolitan distribution, caused respectively by a compulsory intracellular coccidial protozoan and a flagellated parasite, which can affect humans and animals. The objective of this project was to detect by the technique TF-Test Coccidia and polymerase chain reaction (PCR), the occurrence of Cryptosporidium spp. and Giardia spp. in pre-school children and their respective dogs (Canis familiaris) from the Municipality of Araçatuba, São Paulo. For the identification of oocysts of the parasite the new parasitological technique TF-Test Coccidia and PCR were used. From the analysis of these samples, it was verified that 35.00% (35/100) of the children were infected by some kind of intestinal parasite, and 5.00% were microscopically positive for Cryptosporidium spp. and 30,00% for Giardia spp.. In dogs, 3.13% (1/32) were considered positive for Giardia spp., although no animal presented Cryptosporidium spp. Oocyst. in the stool. By PCR 3.00% of the children were positive for Cryptosporidium spp. and 35.00% for Giardia spp.. While for dogs, by the same molecular technique, no animals were considered positive for Cryptosporidium spp. and only 6.25% were positive for Giardia spp.. Thus, was verified that the parasitological technique TF-Test Coccidia presented good concentration and morphology of the parasites found, with a low amount of debris in the fecal smear. For the first time, Cryptosporidium spp. and Giardia... (Complete abstract click electronic access below)
Doutor
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Constantine, Clare Colleen. « Molecular markers, analysis and the population genetics of parasites ». Thesis, Constantine, Clare Colleen (2002) Molecular markers, analysis and the population genetics of parasites. PhD thesis, Murdoch University, 2002. https://researchrepository.murdoch.edu.au/id/eprint/662/.
Texte intégralRésumé :
In this study different molecular techniques are contrasted (RAPD's, allozyme, sequencing mtDNA, sequencing ribosomal spacers) and appropriate analytical methods (allelic and infinite-sites approaches; inbreeding and coalescent models) used for estimating population genetic parameters in parasites. A range of population genetic questions at different scales were chosen to emphasise the importance of tailoring techniques and analytical methods to the particular question being investigated.
The realisation that each question formulated has a particular scale means the appropriate technique and markers must be useful at that scale to attempt to answer the question. The useful scale of a technique depends several factors including the region of DNA examined, the density of sampling of the technique, and the mode of evolution of the markers. Each technique will produce a useful range of variability. Below the lower limit there is no variation, above the upper limit the variation is too high to produce useful comparisons.
Parasites are of interest for many reasons, primarily because they can cause disease and thus impact on their host's population dynamics. They are often closely associated with their hosts and may undergo co-evolution, as well as causing an ongoing immunological "arms race" with their hosts. The parasitic mode of live is found throughout nearly all taxonomic groupings and thus classical models of population genetics based on sexual, diploid vertebrates do not fit well with the entire diversity of parasite groups.
Genetic diversity within and among populations of Echinococcus granulosus was examined contrasting a RAPD dataset with an allozyme dataset. Two models of variation in Echinococcus have been proposed, those of Smyth and Rausch, and the expected genetic structure from each was compared to the observed genetic structure. The premise of Smyth's model, predominant self-fertilisation, was supported, but the resultant pattern of genetic variation followed Rausch's model.
RAPD data, being dominant, present challenges to analysis. An approach to overcome this dominance problem and allow standard allelic frequency analysis is described using the selfing rate estimated from allozyme data. The RAPD data were also analysed using both band-sharing and nucleotide diversity approaches.
A population genetic study of Ostertagia ostertagi in the USA was extended to two different scales: within an Australian state and between the USA and Australian continents. Three alternative explanations for the observed discrepancy between genetic structure and differentiation in an important biological trait, hypobiosis, were explored. A number of programs and analyses were compared including coalescent geneflow estimates.
Variation among multiple copies of two spacer regions of rDNA was examined within individuals of Ostertagia ostertagi. Both the intergenic spacer and internal transcribed spacer 1 regions were found to include repeat regions, with different numbers of repeats creating length differences in clones from the same worm. Multi-copy genes present extra challenges in analysis to ensure that only homologous copies are being compared. Many studies fail to look for variation within populations or within individuals.
The two major conclusions from these examples are that:
1). The study of variation necessarily involves an implicit scale, and markers must be chosen that are appropriate to the question being explored.
2). Using several methods of analysis of genetic data allows contrasts to be made, and if different methods produce similar results gives much more confidence in the conclusions drawn. Incongruence in results leads to new questions and reexamination of the assumptions of each analysis.
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Constantine, Clare Colleen. « Molecular markers, analysis and the population genetics of parasites / ». Access via Murdoch University Digital Theses Project, 2002. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20050817.102006.
Texte intégral
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Newman, Christopher. « The demography and parasitology of the Wytham Woods' badger population ». Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343438.
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Almeida, Fabiana Alves de [UNESP]. « Caracterização da resistência a anti-helmíntico de isolados de Haemonchus contortus e trichostrongylus colubriformis orieundo de ovinos ». Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/87795.
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almeida_fa_me_botib.pdf: 203073 bytes, checksum: 9bdfd8107be2ad00c88771bd9a61ee7c (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O estudo teve por objetivo determinar o grau de eficácia da levamisol, albendazol, ivermectina, moxidectina, closantel e triclorfon em isolados de Haemonchus contortus e Trichostrongylus colubriformis. Quarenta e dois cordeiros da raça Santa Inês, com três meses de idade, foram infectados artificialmente com 4000 larvas infectantes (L3) de H. contortus e 4000 L3 de T. colubriformis. Os animais foram separados em sete grupos, com seis animais cada, os quais receberam os seguintes tratamentos: Grupo 1 – controle, sem tratamento; Grupo 2 - moxidectina injetável (0,2 mg/kg de peso vivo (PV), Cydectin®, Fort Dodge), Grupo 3 - closantel via oral (10 mg/kg de PV, Zuletel®, Laboratório Microsules) Grupo 4 – triclorfon via oral (100 mg/kg de PV, Neguvon®, Bayer); Grupo 5 – fosfato de levamisol injetável (4,7 mg/kg de PV, Ripercol®, Fort Dodge), Grupo 6 - albendazol via oral (5,0 mg/kg de PV, Valbazen®, Pfizer) e o Grupo 7- tratado com ivermectina injetável (0,2 mg/kg de PV, Ivomec® , Merial). A via de administração e a dosagem empregada foram realizadas de acordo com as instruções do fabricante. Amostras de fezes foram coletadas no dia do tratamento, três, sete, 10 e 14 dias após, para a realização de contagem de ovos por grama de fezes (OPG) e cultura de fezes para obtenção e posterior identificação das L3. Os animais foram sacrificados 14 dias após o tratamento para obtenção e quantificação dos vermes presentes no abomaso e no intestino delgado. A eficácia dos tratamentos foi calculada a partir da média aritmética do OPG ou número total de vermes encontrados nos grupos tratados em comparação com os valores do grupo controle. As reduções percentuais das cargas parasitárias de H. contortus foram de 17% para o albendazol, 10% para o levamisol, 45% para moxidectina, 20% para ivermectina, 23% para o closantel e 73% para o triclorfon...
The objective of this study was to determine the efficacy of levamisole, albendazole, ivermectin, moxidectin, closantel and trichlorfon, against Haemonchus contortus and Trichostrongylus colubriformis isolates. Forty-two lambs of the Santa Ines breed, at three months of age, were simultaneously artificially infected with 4000 infective H. contortus larvae (L3) and 4000 T. colubriformis L3. The animals were divided into seven groups with six animals each that received one of the following treatments: Group 1 - control, no treatment; Group 2 - moxidectin (0.2 mg/kg body weight (BW), Cydectin®, Fort Dodge); Group 3 - closantel (10 mg/kg BW, 10% Zuletel®, Microsules Laboratories); Group 4 - trichlorfon (100 mg/kg BW, Neguvon®, Bayer); Group 5 – levamisole phosphate (4.7 mg/kg BW, Ripercol®, Fort Dodge); Group 6 - albendazole (5.0 mg/kg BW, Valbazen®, Pfizer); and Group 7 - treated with ivermectin (0.2 mg/kg BW, Ivomec®, Merial). Fecal samples were collected 3, 7, 10 and 14 days after treatment and processed for nematode fecal egg counts (FEC) and fecal cultures for the production and subsequent identification of L3. The animals were sacrificed 14 days after treatment for collection and quantification of the worms in the abomasum and small intestine. The efficacy of the treatments was calculated from the arithmetic mean of the FEC or worm burden of the treated groups, compared with the values of the control group. The percentage reductions in H. contortus worm burdens were 17% for albendazole, 10% for levamisole, 45% for moxidectin, 20% for ivermectina, 23% for closantel and 73% for trichlorfon. Reductions for T. colubriformis were 19% for albendazole, 28% for ivermectin, 82% for moxidectin and 0% for levamisole, closantel and trichlorfon. The fecal examination was not effective for the detection of resistance to T. colubriformis, since T. colubriformis L3 were not detected... (Complete abstract click electronic access below)
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Rocha, Cláudia Solano [UNESP]. « Análise da relação filogenética entre Triatoma carcavalloi Jurberg, Rocha ; Lent, 1998 ; Triatoma circummaculata Stal, 1859 ; Triatoma klugi Carcavallo, Jurberg, Lent ; Galvão, 2001 e Triatoma rubrovaria Blanchard, 1843 (Hemiptera, Reduviidae) baseada no sequenciamento de genes do DNA mitocondrial e nuclear ». Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/127536.
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000842326.pdf: 1568778 bytes, checksum: 44ee70fd5854d8be4d8c71d1f4d50503 (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A subfamila Triatominae compreende 146 espécies, agrupadas em 18 gêneros e cinco tribos. O gênero Triatoma é o mais representativo da subfamília com 80 espécies descritas, as quais estão agrupadas em oito complexos e oito subcomplexos, sendo essa classificação baseada principalmente em características morfológicas. Triatoma rubravaria é considerado um importante vetor na transmissão da doença de Chagas no Estado do Rio Grande do Sul, uma vez que houve um aumento de sua captura e encontros de colônias intradomiciliares após o programa de combate ao T. infestans. Possui hábitos rupestres e é encontrado em buracos e fendas de locais pedregosos, juntamente com T. carcavalloi, T. circummaculata e T.klugi, os quais mostram semelhanças morfológicas. Marcadores moleculares pertencentes ao DNA nuclear, como os espaçadores internos transcritos (ITS) apresentam uma evolução mais rápida, permitindo estabelecer relações recentes ao passo que a grande subunidade ribossomal 28S (D2), por ser bem conservado, permite estabelecer relação entre organismos distantemente relacionados. Marcadores mitocondriais (Citocromo B - CytB e Citocromo Oxidase I - COI) apresentam taxa de mudança dez vezes mais rápida que aquelas apresentadas pelo DNA nuclear, sendo, portanto, úteis para estabelecer relações filogenéticas entre organismos que divergiram recentemente. A análise Bayesiana por meio de sequencias pertecentes ao mtDNA (CytB e COI) reafirmam o posicionamento de espécies no subcomplexo rubrovaria e indica T. carcavalloi como espécie irmã do grupo formado por T. klugi + T. rubrovaria + T. circummaculata. A análise bayesiana de seis populações de T. rubrovaria mostrou a população coletada em Canguçu isolada das demais, sugerindo que se trata de espécie críptica.
The subfamily Triatominae comprises 146 species grouped in 18 genera and five tribes. The genus Triatoma is the most representative subfamily with 80 described species, which are grouped into eight complex and eight subcomplexes and this classification being based primarily on morphological characteristics. Triatoma rubravaria is considered an important vector in the transmission of Chagas disease in the state of Rio Grande do Sul since it was detected an increase of their capture and meetings colonies household after the program to combat of T. infestans. T. rubrovaria is found in groves and crevices of rocky areas within T. carcavalloi, T. circummaculata and T.klugi, which show morphological similarities. Molecular markers belonging to the nuclear DNA, as the internal transcribed spacers (ITS) have more rapid evolution, establishing recent relationships while the large ribosomal subunit 28S (D2), being well maintained, allows establishing the relationship between distantly related organisms. Mitochondrial markers (Cytochrome B - CytB and Cytochrome Oxidase I - COI) present a rate of change ten times faster than those presented by nuclear DNA, and are therefore useful for establishing phylogenetic relationships between organisms that diverged recently. A Bayesian analysis using mtDNA sequences belonging to (CytB and COI) reaffirmed the positioning of the species and indicates subcomplex rubrovaria and indicates T. carcavalloi as sister species from the group of T. klugi + T. rubrovaria + T. circummaculata. A Bayesian analysis of six populations of T. rubrovaria showed the population collected in Canguçu isolated from the others, suggesting that they are cryptic species.
FAPESP: 09/52236-2
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Amorim, Jandui Almeida. « Levantamento de sarcofagídeos(Diptera) do Brasil incluindo a caracterização molecular de Peckia (Pattonella) intermutans (Walker) / ». Botucatu : [s.n.], 2009. http://hdl.handle.net/11449/87797.
Texte intégralRésumé :
Orientador: Patrícia Jacqueline ThyssenBanca: Wesley Augusto Conde Godoy
Banca: Roseli Tuan
Resumo: Tendo em vista a grande similaridade interespecífica, a identificação de muitos sarcofagídeos usando os caracteres morfológicos é complicada e, sob este aspecto, o desenvolvimento e a aplicação de ferramentas moleculares se mostram cada vez mais necessários à resolução taxonômica e sistemática de diversas espécies. Os dípteros da família Sarcophagidae, especialmente os de hábito necrófilo, têm recebido destaque no campo forense devido à constância com que são encontrados associados a cadáveres, podendo contribuir de forma relevante na estimativa do intervalo pós-morte (IPM), descoberta do local e causa da morte, entre outros. No entanto, para que os espécimes coletados sejam usados de forma apropriada na obtenção de informações para auxiliar o trabalho de perícia, é primordial a identificação correta dos organismos, já que o IPM pode ser calculado com base na taxa de desenvolvimento que varia entre as diferentes espécies. Neste estudo, 194 espécies pertencentes à subfamília Sarcophaginae (Diptera), incluídas em 30 gêneros, são listadas levando em conta suas respectivas distribuições geográficas registradas no território brasileiro. Os gêneros que apresentaram uma grande diversidade de espécies foram Oxysarcodexia (24,7%), Lepidodexia (10,9%), Peckia (10,3%) e Dexosarcophaga (8%). Oxysarcodexia amorosa, O. thornax, Peckia (Euboettcheria) collusor, Peckia (Pattonella) intermutans e Sarcodexia lambens são encontradas na maioria dos estados brasileiros. No arquipélago de Fernando de Noronha, além de Nephochaetopteryx calida, que não apresenta até o momento registro de ocorrência para as localidades continentais, foram encontradas espécies de ampla distribuição no Brasil: O.thornax, (Peckia) chrysostoma e Tricharae (Sarcophagula) occidua. Adicionalmente, a análise da variabilidade genética entre representantes de populações de Peckia... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Due to high interspecific similarity, the identification of many sarcophagids by morphological characters is complicated and, in this way, the development and application of molecular tools have been required to address taxonomic and systematic species. The flies of the Sarcophagidae family, especially necrophagous species, have received attention in the forensic field because of the frequence with which they are found associated with cadavers, thus may contribute to estimate the post-mortem interval (:eMI), the discovery of place and cause of death, among other. However, for the specimens collected are used properly in obtaining information to assist the investigation, the correct identification of species is essential, since the PMI can based on the development rate that varies among different species. In this study, 194 species belonging to the Sarcophaginae subtribe (Diptera), included in 30 genus, are listed taking into account their geographic distribution throughout the Brazilian territory. The genus that showed a great species diversity were: Oxysarcodexia (24.7%), Lepidodexia (10.9%), Peckia (10.3%) and Dexosarcophaga (8%). Oxysarcodexia amorosa, 0. thornax, Peckia (Euboettcheria) collusor, Peckia (Pattonella) intermutans and Sarcodexia lambens are found in most Brazilian states, and only 3 of these were recorded in Fernando de Noronha archipelago, including Nephochaetopteryx calida, which until now has no record of occurrence for continental locations. Furthermore, genetic variability analysis among population of Peckia (Pattonella) intermutans (Walker) from Campinas, Jundiai, Mogi Guayu, Ubatuba (all cities located in Sao Paulo State) and Salvador (Bahia State) were performed based on sequences of carboxy-terminal region of the Cytochrome Oxidase I (COl) mitochondrial gene. This latter approach may help to validate a methodology for molecular identification of species... (Complete abstract click electronic access below)
Mestre
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Rocha, Cláudia Solano. « Análise da relação filogenética entre Triatoma carcavalloi Jurberg, Rocha ; Lent, 1998 ; Triatoma circummaculata Stal, 1859 ; Triatoma klugi Carcavallo, Jurberg, Lent ; Galvão, 2001 e Triatoma rubrovaria Blanchard, 1843 (Hemiptera, Reduviidae) baseada no sequenciamento de genes do DNA mitocondrial e nuclear / ». Araraquara, 2012. http://hdl.handle.net/11449/127536.
Texte intégralRésumé :
Orientador : João Aristeu da RosaBanca: Maria Tercília Vilela de Azeredo Oliveira
Banca: José Clóvis do Prado Júnior
Banca: Marcos Takashi Obara
Banca: Carlos Eduardo de Almeida
Resumo: A subfamila Triatominae compreende 146 espécies, agrupadas em 18 gêneros e cinco tribos. O gênero Triatoma é o mais representativo da subfamília com 80 espécies descritas, as quais estão agrupadas em oito complexos e oito subcomplexos, sendo essa classificação baseada principalmente em características morfológicas. Triatoma rubravaria é considerado um importante vetor na transmissão da doença de Chagas no Estado do Rio Grande do Sul, uma vez que houve um aumento de sua captura e encontros de colônias intradomiciliares após o programa de combate ao T. infestans. Possui hábitos rupestres e é encontrado em buracos e fendas de locais pedregosos, juntamente com T. carcavalloi, T. circummaculata e T.klugi, os quais mostram semelhanças morfológicas. Marcadores moleculares pertencentes ao DNA nuclear, como os espaçadores internos transcritos (ITS) apresentam uma evolução mais rápida, permitindo estabelecer relações recentes ao passo que a grande subunidade ribossomal 28S (D2), por ser bem conservado, permite estabelecer relação entre organismos distantemente relacionados. Marcadores mitocondriais (Citocromo B - CytB e Citocromo Oxidase I - COI) apresentam taxa de mudança dez vezes mais rápida que aquelas apresentadas pelo DNA nuclear, sendo, portanto, úteis para estabelecer relações filogenéticas entre organismos que divergiram recentemente. A análise Bayesiana por meio de sequencias pertecentes ao mtDNA (CytB e COI) reafirmam o posicionamento de espécies no subcomplexo rubrovaria e indica T. carcavalloi como espécie irmã do grupo formado por T. klugi + T. rubrovaria + T. circummaculata. A análise bayesiana de seis populações de T. rubrovaria mostrou a população coletada em Canguçu isolada das demais, sugerindo que se trata de espécie críptica.
Abstract: The subfamily Triatominae comprises 146 species grouped in 18 genera and five tribes. The genus Triatoma is the most representative subfamily with 80 described species, which are grouped into eight complex and eight subcomplexes and this classification being based primarily on morphological characteristics. Triatoma rubravaria is considered an important vector in the transmission of Chagas disease in the state of Rio Grande do Sul since it was detected an increase of their capture and meetings colonies household after the program to combat of T. infestans. T. rubrovaria is found in groves and crevices of rocky areas within T. carcavalloi, T. circummaculata and T.klugi, which show morphological similarities. Molecular markers belonging to the nuclear DNA, as the internal transcribed spacers (ITS) have more rapid evolution, establishing recent relationships while the large ribosomal subunit 28S (D2), being well maintained, allows establishing the relationship between distantly related organisms. Mitochondrial markers (Cytochrome B - CytB and Cytochrome Oxidase I - COI) present a rate of change ten times faster than those presented by nuclear DNA, and are therefore useful for establishing phylogenetic relationships between organisms that diverged recently. A Bayesian analysis using mtDNA sequences belonging to (CytB and COI) reaffirmed the positioning of the species and indicates subcomplex rubrovaria and indicates T. carcavalloi as sister species from the group of T. klugi + T. rubrovaria + T. circummaculata. A Bayesian analysis of six populations of T. rubrovaria showed the population collected in Canguçu isolated from the others, suggesting that they are cryptic species.
Doutor
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Katagiri, Satie. « Avaliação de duas técnicas coproparasitológicas convencionais e de um kit comercial na investigação da epidemiologia de parasitas gastrintestinais de cães no Estado de São Paulo / ». Botucatu : [s.n.], 2006. http://hdl.handle.net/11449/89304.
Texte intégralRésumé :
Orientador : Teresa Cristina G. Oliveira-SequeiraBanca: Lucia Helena O'Dwyer de Oliveira
Banca: Mara Regina Stip Balarin
Resumo: As técnicas coproparasitológicas de concentração por sedimentação e por flutuação e o kit TF-Test® foram utilizadas na investigação da epidemiologia dos parasitas gastrintestinais de cães no Estado de São Paulo. Amostras de fezes de 129 cães errantes e de 125 domiciliados foram colhidas de outubro de 2004 a setembro de 2005 e processadas de acordo com os protocolos do kit TF Test® e dos métodos de centrífugo-sedimentação e centrífugo-flutuação. Os seguintes parasitas e suas respectivas freqüências foram detectados: Ancylostoma spp. (38,2%), Giardia sp. (16,9%), Toxocara canis (8,7%), Tnchuns vulpis (7,1%), Isospora spp. (3,5%), Sarcocystís spp. (2,7%) e Dipy!idium caninum (2,4%). Dos 132 animais parasitados, 79 apresentaram parasitismo único e 53 estavam parasitados por dois ou mais gêneros e/ou espécies. Em cães errantes a prevalência de Ancylostoma spp., T. canis e Giardia sp. e a ocorrência de poliparasitismo foi maior (P < 0,01) que em animais domiciliados. Não houve diferença na freqüência de parasitas intestinais relacionada ao sexo, raça ou ao tratamento anti-helmíntico dos animais (P > 0,05), no entanto a freqüência de T. canis foi maior (P < 0,05) em cães jovens. Com relação à sazonalidade, a detecção de cistos de Giardia sp. foi mais freqüente nos meses de outubro a março. A sensibilidade diagnóstica do método de centrífugo-flutuação foi maior para todos os parasitas intestinais diagnosticados, porém somente no caso de Ancylostoma spp. essa diferença (P <0,05) se expressou em termos de uma maior freqüência de detecção de cães infectados. O elenco de parasitas diagnosticados na região estudada faz com que a técnica de centrifugo-flutuação com sulfato de zinco seja a mais apropriada tanto para os estudos epidemiológicos como para o diagnóstico individual, especialmente nas infecções subclínicas.
Abstract: The sedimentation and flotation procedures for concentration of fecal specimens and the commercial device TF were used, in an epidemiological investigation of gastrointestinal parasites of dogs in São Paulo state. Fecal samples from 129 stray dogs and 125 dogs with an owner were collected from October 2004 to September 2005. AlI samples were concentrated by the sedimentation and flotation methods and by TF-Test® device. The following parasites, and their respective frequency were diagnosed in fecal samples : Ancylostoma spp. (38,2%), Giardia sp. (16,9%), Toxocara canis (8,7%), Tnchuris vulpis (7,1%), Isospora spp. (3,5%), Sarcocystis spp. (2,7%) and Dipylidium caninum (2,4%). Fifty-three out of 132 infected animais had mixed infection with two or more parasite genera. The prevalence of Ancy!ostoma spp., 1 canis and Giardia sp. as well as the occurrence of mixed infections were significantly higher in stray dogs (P <0,01) than in dogs with an owner. No effect of gender, breed and anti-helminthic treatment (P> 0,05) on the parasite frequency was observed, but the frequency of T. canis was higher (P < 0,05) in young animais. Giardia sp. cysts were more frequently detected from October to March. The centrifugation-flotation method was generally more accurate in the diagnosis of ali intestinal parasites of dogs, but only for Ancylostoma spp. this difference was observed in terms of prevalence. The species of parasites found in the studied region make the zinc sulfate flotation the most appropriate method not only to epidemiological studies, but also to individual diagnosis, speciaily in subciinical infections.
Mestre
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Stewart, Alexander Thomas. « Eco-immunology : thermal variation and parasitology of the three-spined stickleback ». Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/95911/.
Texte intégralRésumé :
Global warming and temperature variation are likely to have profound impacts on fish as ectotherms that are heavily reliant on environmental temperature for growth, development, metabolism and immunity. This study addresses the impact of climate change on the development of infection and immunity in three-spined sticklebacks (Gasterosteus aculeatus) and their common parasites. In addition to thermal consequences on host parasite interactions, the study also addressed the effects of co-infection on parasite intensities and pathology on host swimming ability. Experiments were designed to mimic global warming, temperature variability and stochasticity (Chapters 3-5). Temperature during exposure to Saprolegnia parasitica was the major determinant of high infection prevalence and intensity with historical temperature exposure having little impact (Chapters 3-5). A further contributor to infection risk was higher host body condition (Chapter 3 and 5), attributed to a trade-off between host immunity and condition, higher condition individuals investing less in immunity supported by a decline in β-def expression in high condition fish (Chapter 5). Peak infection intensities in Gyrodactylus gasterostei were dependent on temperature variability and the host’s immune response. In variable conditions, an established G. gasterostei was better able to adapt to a changing environment than the host’s response causing higher peak infection intensities (Chapter 3 and 4). Temperature, and not photoperiod, was the major cause of circannual rhythm in host immunity (Chapter 6). Co-infection between G. gasterostei and A. foliaceus, revealed higher gyrodactylid infection peaks compared to hosts infected with G. gasterostei alone suggesting that immunomodulation by A. foliaceus. Lastly, pathology, rather than drag, reduced burst and long-term swimming performance of sticklebacks infected with A. foliaceus. Many of the factors highlighted have implications for aquaculture. High aquaculture feeding regimens, resulting in higher body condition, co-infection and temperature, all could severely increase morbidity and mortality of fish in a parasite species dependant manner.
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Wilmott, S. « Mathematical modelling and analysis of some problems in parasitology and ecology ». Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382699.
Texte intégral
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Thawani, Neeta. « The contribution of host-and parasite-derived factors to erythropoietic suppression underlying the development of malarial anemia / ». Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=111901.
Texte intégralRésumé :
Severe anemia is the most prevalent life-threatening complication of malaria infection. In addition to destruction of red blood cells (RBC), decreased RBC production or erythropoietic suppression has been shown to contribute to malarial anemia. The mechanism of this suppression is unknown, but it is considered to be multifactorial since erythropoietic suppression can be observed in the presence of both inflammatory mediators and parasite-derived factors. Experiments presented in this thesis aimed at determining the role of host cytokines released in response to blood-stage malaria infection and parasite-derived factors in erythropoietic suppression underlying the development of malarial anemia. Pro-inflammatory cytokines released during malaria infection have been proposed to play a central role in erythroid suppression. To dissect the discrete roles of these cytokines in the processes leading to anemia, mice were treated with CpG-oligodeoxynucleotides (CpG-ODN) which, like malaria infection in humans and experimental mouse models, induces an acute type 1 pro-inflammatory response. CpG-ODN treatment induced anemia, which was associated with suppressed erythropoiesis and reduced RBC survival. Importantly, CpG-ODN-induced IFN-gamma was found to be the major factor mediating erythropoietic suppression but not decreased RBC survival. We also studied the roles of Th1, Th2 and anti-inflammatory cytokines produced in response to Plasmodium chabaudi AS infection in the development of erythropoietic suppression during blood-stage malaria. Signal transducer and activator of transcription (STAT)6, required for signaling of the Th2 cytokines IL-4 and IL-13, was shown to play a critical role in malarial anemia by inhibiting the proliferation and differentiation of erythroid cells. We also observed that suppressed erythropoiesis is a general feature in mice infected with various rodent Plasmodium species that differ in their clinical manifestations and immune responses. Since parasite-derived factors have been shown to contribute to malarial pathogenesis including anemia, the contribution of P. falciparum - and P. yoelii-derived products to erythropoietic suppression was investigated. Both Plasmodium-derived and synthetic hemozoin (Hz) suppressed the proliferation but not the maturation of erythroid progenitor cells in vitro. However, P. yoelii-derived Hz but not synthetic Hz induced transient anemia in mice. These findings provide novel insights into the complex interactions between the parasite and host immune system and the regulation of erythropoiesis during severe malarial anemia.
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Santos, Michelle Cardoso dos [UNESP]. « Resposta imunológica de cordeiros às infecções artificiais por Haemonchus contortus e Haemonchus placei ». Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87793.
Texte intégralRésumé :
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000731361.pdf: 750399 bytes, checksum: 349ccb1a1690653ecab3850aed937652 (MD5)A proteção conferida pela resposta imunológica de cordeiros, às infecções seriadas com Haemonchus contortus (Hc) e Haemonchus placei (Hp) e desafios, por infecções homólogas e heterólogas, com ambas as espécies, foi avaliada. Quarenta e dois cordeiros, com peso corporal inicial médio de 21,3 kg, foram divididos em sete grupos experimentais. No primeiro grupo, 12 cordeiros receberam infecções seriadas (Is) 12 vezes (três vezes por semana) durante quatro semanas, com 500 larvas infectantes (L3) de H. placei e foram posteriormente desafiados (D), em dose única, com 4000 L3 de H. placei (Grupo IsHp+DHp, n=6) ou com 4000 L3 de H. contortus (Grupo IsHp+DHc, n=6). Os animais do segundo grupo (n=12) foram infectados com H. contortus da mesma maneira que o grupo 1 (500 L3, três vezes por semana) e foram desafiados com 4000 L3 de H. contortus (Grupo IsHc+DHc, n=6) ou com 4000 L3 de H. placei (Grupo IsHc+DHp, n=6). O terceiro grupo foi somente desafiado com 4000 L3 de H. placei (Grupo DHp, n=6), 4000 L3 de H. contortus (Grupo DHc, n=6), ou permaneceram livres de infecções durante todo o período experimental (Grupo Controle, n=6). Análises hematológicas e contagem de ovos por grama de fezes (OPG) foram realizadas semanalmente, o plasma sanguíneo foi armazenado para a realização de análises imunológicas (teste de ELISA). Após a eutanásia dos animais os parasitas foram recuperados, bem como tecido e muco abomasal. Animais que receberam infecções homólogas por H. placei (Grupo IsHp+DHp) apresentaram intensa resposta imune com elevados níveis de imunoglobulinas anti-parasita e número de células inflamatórias na mucosa do abomaso. Em adição, esse grupo (IsHp+DHp) apresentou a menor taxa de estabelecimento de parasitas (2,68% de 4000 L3). Estes resultados podem ser associados às infecções em série, que estimularam uma forte resposta imunológica contra a espécie H. placei, pois...
The protection conffered by serial infections with Haemonchus contortus (Hc) and Haemonchus placei (Hp) was evaluated in lambs. Forty two lambs, with initial average body weight of the 21.3 kg, were divided in three experimental groups. In the first group, 12 lambs was serially infected (Si) 12 times (three times a week) for four weeks, with 500 infective larvae (L3) of H. placei and then challenged (Ch), in a single dose, with 4000 L3 of H. placei (Group SiHp+ChHp, n=6) or with 4000 L3 of H. contortus (Group SiHp+ChHc, n=6). The animals of the second group (n=12) were infected with H. contortus, in the same way that group 1 (500 L3, three times a week) and then challenged with 4000 L3 of H. contortus (Group SiHc+ChHc, n=6) or with 4000 L3 of H. placei (Group SiHc+ChHp, n=6). A third group of lambs was single challenged with 4000 L3 of H. placei (Group ChHp, n=6), 4000 L3 of H. contortus (Group ChHc, n=6), or remained uninfected throughout the trial period (Group Control, n=6). Haematological and fecal eggs counts (FEC) occurred weekely, the blood plasma was stored to immunological exams (ELISA test). After the animals sacrifice, the worms were recoverd, as well as, abomasal tissue and mucus. Animals that received homologous infection with H. placei (Group SiHp+ChHp) presented the most intense immune response and number of inflammatory cells in the abomasal mucosa. In adition, this group (SiHp+ChHp) presented the lowest rate of parasite establishment (2.68% of the 4000 L3). These results can be associated to serial infection that stimulated to strong immune respose against H. placei, which presents lower adaptability to sheep. The opposite was observed in animals that only received the challenge infection, with H. placei (group ChHp), in which the rate of establishment was relatively high (25.3%). However, the animals that received heterologous infection, previously infected serially with H. placei and ...
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Cruz, Leonardo Dominici [UNESP]. « Padrões ecológicos da relação de parasitismo entre ácaros mesostigmata e alguns roedores neotropicais ». Universidade Estadual Paulista (UNESP), 2012. http://hdl.handle.net/11449/106546.
Texte intégralRésumé :
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cruz_ld_dr_rcla.pdf: 1201063 bytes, checksum: cc322ba66d3b7aeaa96f2e1ae46979e9 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Ácaros mesostigmatídeos e seus roedores hospedeiros compreendem um dos mais ricos e diversos sistemas parasito-hospedeiro da região Neotropical. A maior parte do conhecimento disponível sobre este sistema refere-se a listas de ocorrências, descrições de espécies parasitas e relações de especificidade hospedeira em escalas locais. Estudos ecológicos com o objetivo de procurar padrões de estruturas de comunidades de espécies parasitas, bem como investigar os possíveis processos subjacentes à organização destas comunidades são escassos. Dessa forma, o presente estudo tenta contribuir para o conhecimento ecológico deste sistema parasito-hospedeiro. No Capítulo 1, investigou-se a existência de padrões organizacionais nas infracomunidades de mesostigmatídeos em duas populações do hospedeiro roedor Oligoryzomys nigripes, bem como possíveis fatores subjacentes aos padrões observados. Demonstrou-se que as infracomunidades de mesostigmatídeos podem apresentar variações na sua organização, indo desde infracomunidades completamente aleatórias, a infracomunidades estruturadas. Fatores relacionados à história de vida dos hospedeiros podem ser responsáveis pela estruturação das infracomunidades de mesostigmatídeos; todavia, a proposição de padrões gerais não foi possível, principalmente devido a grande diversidade de espécies parasitas e hospedeiras envolvidas na região Neotropical. No Capítulo 2, investigou-se a existência de padrões de similaridades entre as comunidades de mesostigmatídeos em duas escalas observacionais: comunidade componente e comunidade composta. Os resultados obtidos demonstraram que as similaridades entre as comunidades componentes e entre as comunidades compostas geralmente são baixas, não sendo influenciadas pela distância geográfica e pela dissimilaridade ambiental entre as localidades...
Mites and their rodent hosts mesostigmatídeos comprise one of the richest and most diverse host-parasite systems of the Neotropical region. Most of the knowledge available about this system refers to occurrence lists, parasite species descriptions and host specificity relationships at local scales. Ecological studies with the aim looking for structure patterns of parasite communities, as well as investigate the possible processes underlying the organization of these communities are scarce. Thus, this study attempts to contribute to the ecological knowledge of this host-parasite system. In Chapter 1, we investigated the existence of organizational patterns in infracommunities of Mesostigmata mites of the two populations of the rodent host Oligoryzomys nigripes as well as possible factors underlying the observed patterns. It was demonstrated that the infracommunities of Mesostigmata mites may vary in their organization, ranging from completely random infracommunities to structured infracommunities. Factors related to the hosts life histories may be responsible for structuring Mesostigmata mites infracommunities. However, the proposition of general patterns was not possible, mainly due to the great diversity of parasites and host species involved in Neotropical region. In Chapter 2, we investigated the existence of similarity patterns among Mesostigmata mites communities in two levels: component community and compound community. The results showed that the similarities among the component communities and among the compound communities generally are low, not being influenced by geographical distance and environmental dissimilarity among the localities. However, the similarities of Mesostigmata mites among the compound communities were positively related to the host faunas similarities among the localities... (Complete abstract click electronic access below)
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Cruz, Leonardo Dominici. « Padrões ecológicos da relação de parasitismo entre ácaros mesostigmata e alguns roedores neotropicais / ». Rio Claro : [s.n.], 2012. http://hdl.handle.net/11449/106546.
Texte intégralRésumé :
Orientador: Claudio José Von ZubenBanca: Aricio Xavier Linhares
Banca: Gilberto Salles Gazêta
Banca: Fabio Akashi Hernandes
Banca: Karim Christina Scopinho Furquim
Resumo: Ácaros mesostigmatídeos e seus roedores hospedeiros compreendem um dos mais ricos e diversos sistemas parasito-hospedeiro da região Neotropical. A maior parte do conhecimento disponível sobre este sistema refere-se a listas de ocorrências, descrições de espécies parasitas e relações de especificidade hospedeira em escalas locais. Estudos ecológicos com o objetivo de procurar padrões de estruturas de comunidades de espécies parasitas, bem como investigar os possíveis processos subjacentes à organização destas comunidades são escassos. Dessa forma, o presente estudo tenta contribuir para o conhecimento ecológico deste sistema parasito-hospedeiro. No Capítulo 1, investigou-se a existência de padrões organizacionais nas infracomunidades de mesostigmatídeos em duas populações do hospedeiro roedor Oligoryzomys nigripes, bem como possíveis fatores subjacentes aos padrões observados. Demonstrou-se que as infracomunidades de mesostigmatídeos podem apresentar variações na sua organização, indo desde infracomunidades completamente aleatórias, a infracomunidades estruturadas. Fatores relacionados à história de vida dos hospedeiros podem ser responsáveis pela estruturação das infracomunidades de mesostigmatídeos; todavia, a proposição de padrões gerais não foi possível, principalmente devido a grande diversidade de espécies parasitas e hospedeiras envolvidas na região Neotropical. No Capítulo 2, investigou-se a existência de padrões de similaridades entre as comunidades de mesostigmatídeos em duas escalas observacionais: comunidade componente e comunidade composta. Os resultados obtidos demonstraram que as similaridades entre as comunidades componentes e entre as comunidades compostas geralmente são baixas, não sendo influenciadas pela distância geográfica e pela dissimilaridade ambiental entre as localidades... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Mites and their rodent hosts mesostigmatídeos comprise one of the richest and most diverse host-parasite systems of the Neotropical region. Most of the knowledge available about this system refers to occurrence lists, parasite species descriptions and host specificity relationships at local scales. Ecological studies with the aim looking for structure patterns of parasite communities, as well as investigate the possible processes underlying the organization of these communities are scarce. Thus, this study attempts to contribute to the ecological knowledge of this host-parasite system. In Chapter 1, we investigated the existence of organizational patterns in infracommunities of Mesostigmata mites of the two populations of the rodent host Oligoryzomys nigripes as well as possible factors underlying the observed patterns. It was demonstrated that the infracommunities of Mesostigmata mites may vary in their organization, ranging from completely random infracommunities to structured infracommunities. Factors related to the hosts life histories may be responsible for structuring Mesostigmata mites infracommunities. However, the proposition of general patterns was not possible, mainly due to the great diversity of parasites and host species involved in Neotropical region. In Chapter 2, we investigated the existence of similarity patterns among Mesostigmata mites communities in two levels: component community and compound community. The results showed that the similarities among the component communities and among the compound communities generally are low, not being influenced by geographical distance and environmental dissimilarity among the localities. However, the similarities of Mesostigmata mites among the compound communities were positively related to the host faunas similarities among the localities... (Complete abstract click electronic access below)
Doutor
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Almeida, Fabiana Alves de. « Caracterização da resistência a anti-helmíntico de isolados de Haemonchus contortus e trichostrongylus colubriformis orieundo de ovinos / ». Botucatu, 2009. http://hdl.handle.net/11449/87795.
Texte intégralRésumé :
Orientador: Alessandro Francisco Talamini do AmaranteBanca: Maria Conceição Zocoller Seno
Banca: Raquel A. da Rocha de Oliveira
Resumo: O estudo teve por objetivo determinar o grau de eficácia da levamisol, albendazol, ivermectina, moxidectina, closantel e triclorfon em isolados de Haemonchus contortus e Trichostrongylus colubriformis. Quarenta e dois cordeiros da raça Santa Inês, com três meses de idade, foram infectados artificialmente com 4000 larvas infectantes (L3) de H. contortus e 4000 L3 de T. colubriformis. Os animais foram separados em sete grupos, com seis animais cada, os quais receberam os seguintes tratamentos: Grupo 1 - controle, sem tratamento; Grupo 2 - moxidectina injetável (0,2 mg/kg de peso vivo (PV), Cydectin®, Fort Dodge), Grupo 3 - closantel via oral (10 mg/kg de PV, Zuletel®, Laboratório Microsules) Grupo 4 - triclorfon via oral (100 mg/kg de PV, Neguvon®, Bayer); Grupo 5 - fosfato de levamisol injetável (4,7 mg/kg de PV, Ripercol®, Fort Dodge), Grupo 6 - albendazol via oral (5,0 mg/kg de PV, Valbazen®, Pfizer) e o Grupo 7- tratado com ivermectina injetável (0,2 mg/kg de PV, Ivomec® , Merial). A via de administração e a dosagem empregada foram realizadas de acordo com as instruções do fabricante. Amostras de fezes foram coletadas no dia do tratamento, três, sete, 10 e 14 dias após, para a realização de contagem de ovos por grama de fezes (OPG) e cultura de fezes para obtenção e posterior identificação das L3. Os animais foram sacrificados 14 dias após o tratamento para obtenção e quantificação dos vermes presentes no abomaso e no intestino delgado. A eficácia dos tratamentos foi calculada a partir da média aritmética do OPG ou número total de vermes encontrados nos grupos tratados em comparação com os valores do grupo controle. As reduções percentuais das cargas parasitárias de H. contortus foram de 17% para o albendazol, 10% para o levamisol, 45% para moxidectina, 20% para ivermectina, 23% para o closantel e 73% para o triclorfon... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The objective of this study was to determine the efficacy of levamisole, albendazole, ivermectin, moxidectin, closantel and trichlorfon, against Haemonchus contortus and Trichostrongylus colubriformis isolates. Forty-two lambs of the Santa Ines breed, at three months of age, were simultaneously artificially infected with 4000 infective H. contortus larvae (L3) and 4000 T. colubriformis L3. The animals were divided into seven groups with six animals each that received one of the following treatments: Group 1 - control, no treatment; Group 2 - moxidectin (0.2 mg/kg body weight (BW), Cydectin®, Fort Dodge); Group 3 - closantel (10 mg/kg BW, 10% Zuletel®, Microsules Laboratories); Group 4 - trichlorfon (100 mg/kg BW, Neguvon®, Bayer); Group 5 - levamisole phosphate (4.7 mg/kg BW, Ripercol®, Fort Dodge); Group 6 - albendazole (5.0 mg/kg BW, Valbazen®, Pfizer); and Group 7 - treated with ivermectin (0.2 mg/kg BW, Ivomec®, Merial). Fecal samples were collected 3, 7, 10 and 14 days after treatment and processed for nematode fecal egg counts (FEC) and fecal cultures for the production and subsequent identification of L3. The animals were sacrificed 14 days after treatment for collection and quantification of the worms in the abomasum and small intestine. The efficacy of the treatments was calculated from the arithmetic mean of the FEC or worm burden of the treated groups, compared with the values of the control group. The percentage reductions in H. contortus worm burdens were 17% for albendazole, 10% for levamisole, 45% for moxidectin, 20% for ivermectina, 23% for closantel and 73% for trichlorfon. Reductions for T. colubriformis were 19% for albendazole, 28% for ivermectin, 82% for moxidectin and 0% for levamisole, closantel and trichlorfon. The fecal examination was not effective for the detection of resistance to T. colubriformis, since T. colubriformis L3 were not detected... (Complete abstract click electronic access below)
Mestre
28
Santos, Michelle Cardoso dos. « Resposta imunológica de cordeiros às infecções artificiais por Haemonchus contortus e Haemonchus placei / ». Botucatu, 2013. http://hdl.handle.net/11449/87793.
Texte intégralRésumé :
Orientador: Alessandro Francisco Talamini do AmaranteBanca: Helder Louvandini
Banca: Paulo Francisco Domingues
Resumo: A proteção conferida pela resposta imunológica de cordeiros, às infecções seriadas com Haemonchus contortus (Hc) e Haemonchus placei (Hp) e desafios, por infecções homólogas e heterólogas, com ambas as espécies, foi avaliada. Quarenta e dois cordeiros, com peso corporal inicial médio de 21,3 kg, foram divididos em sete grupos experimentais. No primeiro grupo, 12 cordeiros receberam infecções seriadas (Is) 12 vezes (três vezes por semana) durante quatro semanas, com 500 larvas infectantes (L3) de H. placei e foram posteriormente desafiados (D), em dose única, com 4000 L3 de H. placei (Grupo IsHp+DHp, n=6) ou com 4000 L3 de H. contortus (Grupo IsHp+DHc, n=6). Os animais do segundo grupo (n=12) foram infectados com H. contortus da mesma maneira que o grupo 1 (500 L3, três vezes por semana) e foram desafiados com 4000 L3 de H. contortus (Grupo IsHc+DHc, n=6) ou com 4000 L3 de H. placei (Grupo IsHc+DHp, n=6). O terceiro grupo foi somente desafiado com 4000 L3 de H. placei (Grupo DHp, n=6), 4000 L3 de H. contortus (Grupo DHc, n=6), ou permaneceram livres de infecções durante todo o período experimental (Grupo Controle, n=6). Análises hematológicas e contagem de ovos por grama de fezes (OPG) foram realizadas semanalmente, o plasma sanguíneo foi armazenado para a realização de análises imunológicas (teste de ELISA). Após a eutanásia dos animais os parasitas foram recuperados, bem como tecido e muco abomasal. Animais que receberam infecções homólogas por H. placei (Grupo IsHp+DHp) apresentaram intensa resposta imune com elevados níveis de imunoglobulinas anti-parasita e número de células inflamatórias na mucosa do abomaso. Em adição, esse grupo (IsHp+DHp) apresentou a menor taxa de estabelecimento de parasitas (2,68% de 4000 L3). Estes resultados podem ser associados às infecções em série, que estimularam uma forte resposta imunológica contra a espécie H. placei, pois ...
Abstract: The protection conffered by serial infections with Haemonchus contortus (Hc) and Haemonchus placei (Hp) was evaluated in lambs. Forty two lambs, with initial average body weight of the 21.3 kg, were divided in three experimental groups. In the first group, 12 lambs was serially infected (Si) 12 times (three times a week) for four weeks, with 500 infective larvae (L3) of H. placei and then challenged (Ch), in a single dose, with 4000 L3 of H. placei (Group SiHp+ChHp, n=6) or with 4000 L3 of H. contortus (Group SiHp+ChHc, n=6). The animals of the second group (n=12) were infected with H. contortus, in the same way that group 1 (500 L3, three times a week) and then challenged with 4000 L3 of H. contortus (Group SiHc+ChHc, n=6) or with 4000 L3 of H. placei (Group SiHc+ChHp, n=6). A third group of lambs was single challenged with 4000 L3 of H. placei (Group ChHp, n=6), 4000 L3 of H. contortus (Group ChHc, n=6), or remained uninfected throughout the trial period (Group Control, n=6). Haematological and fecal eggs counts (FEC) occurred weekely, the blood plasma was stored to immunological exams (ELISA test). After the animals sacrifice, the worms were recoverd, as well as, abomasal tissue and mucus. Animals that received homologous infection with H. placei (Group SiHp+ChHp) presented the most intense immune response and number of inflammatory cells in the abomasal mucosa. In adition, this group (SiHp+ChHp) presented the lowest rate of parasite establishment (2.68% of the 4000 L3). These results can be associated to serial infection that stimulated to strong immune respose against H. placei, which presents lower adaptability to sheep. The opposite was observed in animals that only received the challenge infection, with H. placei (group ChHp), in which the rate of establishment was relatively high (25.3%). However, the animals that received heterologous infection, previously infected serially with H. placei and ...
Mestre
29
Taylor-Brown, Emilie. « Miasmas, mosquitoes, and microscopes : parasitology and the British literary imagination, 1885-1935 ». Thesis, University of Warwick, 2016. http://wrap.warwick.ac.uk/84851/.
Texte intégralRésumé :
This thesis explores the complex and multi-form exchanges between parasitology and the British literary imagination in the period 1885 to 1935. This fifty-year period, which takes the institutionalisation of parasitology as its mid-point, was a significant cultural moment, witnessing the diversification of medicine into research specialisms. In the case of parasitology, this increasing specialisation was accompanied, seemingly paradoxically, by what we would now call interdisciplinarity. Parasitologists consciously engaged with literary myths of nationhood in order to garner widespread support for their sub-field, and help communicate their research. Meanwhile they provided the public with significant motifs for exploring a variety of social, cultural, and political relationships. Literary authors’ engagement with disciplinary politics provided them with a means of interrogating British national identity and critiquing or supporting British imperial rule. The dialogues between parasitology and the British literary imagination in this period ultimately articulated anxieties concerning “self” and “other” at the biological, psychological, and ideological levels. As I will argue, the parasite-host relationship became a significant framework for understanding identity, and consequently was deeply embedded in, and inseparable from, understandings of what it meant to be British in an increasingly global world. In order to access the dialogues between parasitology and the British literary imagination, I will use a variety of sources, including: literary fiction, poetry, satire, newspaper articles, personal correspondence between doctors, parasitologists’ research diaries, and scientific publications. In analysing this dialogue, which might be taken as a case study of wider literature-science relationships in this time period, we gain a greater understanding of the politics of narrating science. Building on previous work in the burgeoning field of literature and science studies, this thesis will seek to explore the utility of interdisciplinary approaches to research and communication, investigate the processes behind the public understanding of science, and interrogate the cultural and historical framing of science.
30
Guilmot, Aline. « Production of IFN-gamma by neonatal Natural Killer cells in response to Trypanosoma cruzi and cross-talk with monocytes ». Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209457.
Texte intégralRésumé :
La maladie de Chagas, due au protozoaire Trypanosoma cruzi, est un important problème de santé publique en Amérique latine. Le parasite peut se transmettre à l’homme via un vecteur de la famille des triatomes, par transfusion sanguine ou transplantation d’organe et congénitalement de la mère à son fœtus. Le Laboratoire de Parasitologie s’est particulièrement intéressé à la maladie de Chagas congénitale. Dans le cadre de cette thématique, le Laboratoire a montré que les nouveau-nés congénitalement infectés par T. cruzi développent une forte réponse lymphocytaire T CD8+ spécifique semblable à celle des adultes, accompagnée d’une production d’interféron-gamma (IFN-g), et ce en dépit de l’immaturité bien connue du système immun néonatal. En effet, le système immun néonatal est naturellement orienté vers le développement de réponses immunes Th2 tandis que la réponse Th1 est inhibée. De multiples mécanismes sont à l’origine de cette déviation en début de vie. Certaines déficiences au niveau des cellules du système immun inné y contribuent, dont la difficulté des cellules dendritiques (DCs) à produire de l’IL-12, cytokine clé dans l’induction d’une réponse Th1. Les multiples déficiences du système immun en début de vie rendent les nouveau-nés et jeunes enfants particulièrement sensibles aux pathogènes et limitent l’efficacité des vaccins administrés en début de vie. Afin de mieux connaître les mécanismes par lesquels T. cruzi induit cette forte réponse immune de type 1 chez les nouveau-nés, nous nous sommes intéressés à l’activation de la réponse immune innée par le parasite. De nombreuses cellules peuvent être impliquées dans la mise en place d’une réponse de type 1, dont les cellules dendritiques (DCs), les monocytes et les cellules NK. Le Laboratoire de Parasitologie a montré que T. cruzi activait in vitro les DCs néonatales, les rendant capables d’induire une réponse lymphocytaire T plus orientée vers la production d’IFN-g. D’autres données obtenues chez les nouveau-nés congénitalement infectés par T. cruzi suggèrent que les cellules NK ont été activées in utero quand le parasite a été transmis par la mère infectée. Nous nous sommes ici intéressés à la capacité des cellules NK néonatales à produire rapidement de l’IFN-g en réponse à T. cruzi. Une telle production précoce est en effet un élément contribuant à orienter une réponse immune de type 1.
Nous avons effectué des co-cultures de cellules mononucléaires de sang de cordon de nouveau-nés sains (CBMC) ou de sang périphérique adulte (PBMC) avec des trypomastigotes vivants de T. cruzi. Nos résultats montrent qu’en présence d’IL-15, T. cruzi induit une forte production d’IFN-g par les CBMC. Cette réponse est précoce et est accompagnée d’une production de TNF-a mais pas d’IL-10. Les cellules NK CD56brightCD16-/low et CD56dimCD16- sont les meilleures productrices d’IFN-g dans les deux groupes d’âges. La réponse des cellules NK néonatales est substantielle mais reste légèrement inférieure à celle des cellules adultes. Nous avons par ailleurs observé un déficit de production précoce d’IFN-g par les cellules T CD3+CD56+ (NK-like) et CD3+CD56- (« classiques ») néonatales par rapport aux cellules adultes.
La réponse IFN-g par les cellules NK est proportionnelle aux concentrations de parasites et d’IL-15 et accompagnée d’une activation phénotypique des cellules NK. Il est bien connu que des cellules accessoires telles que les cellules dendritiques et les monocytes contribuent généralement à activer indirectement les cellules NK. Des expériences de déplétion cellulaire indiquent que la production d’IFN-g par les cellules NK néonatales sensibilisées par l’IL-15 fait intervenir les monocytes mais pas les DCs myéloïdes, et qu’un contact avec les monocytes est nécessaire. De plus, elle requiert un contact du parasite vivant avec les CBMC et implique l’engagement des TLR2 et TLR4, ainsi qu’une production endogène d’IL-12.
Enfin, nous avons observé que les monocytes, et non les DCs myéloïdes, sont la source précoce de l’IL-12p70. Les parasites sont capables d’induire la synthèse de cette cytokine importante pour l’initiation d’une réponse de type 1 en l’absence de cytokines additionnelles, aussi bien dans les monocytes néonataux qu’adultes. La synthèse d’IL-12 par les monocytes s’accompagne d’une augmentation de l’expression de molécules co-activatrices CD40, CD80 et CD83 à leur surface. Ces dernières pourraient dès lors jouer un rôle supplémentaire dans l’activation indirecte des cellules NK néonatales par le parasite.
Cet ensemble de résultats montre que T. cruzi active les cellules néonatales du système immunitaire et plus particulièrement la production d’IL-12 par les monocytes et d’IFN-g par les cellules NK. Cette voie d’activation monocytes – IL-12 – cellules NK – IFN-g pourrait contribuer à la levée de l’immaturité du système immun des nouveau-nés congénitalement infectés décrite plus haut. Ces observations ont d’importantes implications pour la compréhension des mécanismes de protection en début de vie et pourraient aboutir à la mise au point d’un nouvel adjuvant vaccinal permettant de réduire la polarisation Th2 physiologique des nouveau-nés.
Doctorat en Sciences biomédicales et pharmaceutiques
info:eu-repo/semantics/nonPublished
31
Júnior, Mauro Cardoso. « Taxonomia das linhagens de Acanthobothrium van Beneden, 1850 (Eucestoda : Tetraphyllidea) parasitas de Potamotrygonidae (Chondrichthyes : Myliobatiformes) ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-07122010-175601/.
Texte intégralRésumé :
Membros de Acanthobothrium (Cestoda: Tetraphyllidea: Onchobothriidae) são primariamente parasitas elasmobrânquios em todos os oceanos. No entanto, algumas linhagens são encontradas em arraias de água doce da família Potamotrygonidae da região Neotropical. O reconhecimento das entidades taxonômicas que participam de um sistema parasita/hospedeiro é essencial para que estudos comparativos que visam elucidar os padrões e processos responsáveis pela diversificação destes systemas. Atualmente, 175 espécies são reconhecidas para o gênero, das quais apenas seis parasitam exclusivamente potamotrigonídeos (A. terezae, A. quinonesi, A. amazonensis, A. regoi, A. ramiroi e A. peruviense). Historicamente, a maioria das espécies de Acanthobothrium, em particular as espécies parasitas de potamotrigonídeos, foi descrita baseandose em um número restrito de exemplares provindos de localidades muito distantes umas das outras e coletados em poucas espécies de potamotrigonídeos. Esta prática tem conduzido pesquisadores a denominar novos táxons sob a premissa de que estas linhagens exibem pouca variação morfológica. Neste trabalho, foram examinados 649 espécimes de hospedeiros, representando 10 espécies e 14 morfo-espécies de potamotrigonídeos, provenientes de 10 sub-bacias hidrográficas. Somente cinco espécies de Acanthobothrium são reconhecidas neste trabalho para o sistema de água doce, A. terezae (sinônimo A. ramiroi), A. quinonesi (sinônimos A. regoie A. peruviense), A. amazonensis e duas novas espécies A. sp. n.1 e A. sp. n. 2. Verificouse que estas cinco espécies de Acanthobothrium parasitam 27 espécies de potamotrigonídeos em quase todas as sub-bacias hidrográficas da América do Sul, demonstrando um padrão de especificidade distinto de seus congêneres marinhos. As diferenças observadas nos padrões de especificidade entre estes dois ambientes pode decorrer da inexistência de amostras representativas de grupos monofiléticos de hospedeiros marinhos e/ou a despreocupação em obter amostragens adequadas de espécimens seja de hospedeiros ou parasitas. Novas fontes de dados (e.g., molecular) são necessárias para entender melhor os limites do atual status taxonômico das espécies de água doce de Acanthobothrium. Outra recomendação para acessar a variabilidade morfológica de tetrafilídeos, em geral, é o aumento do tamanho amostral considerando diferentes áreas e hospedeiros. A representatividade biogeográfica é fundamental para a compreensão da biodiversidade. Sistematas que trabalham com a taxonomia de tetrafilídeos devem ter cautela no uso de dados morfométricos e merísticos na diagnose de espécies que são descritas com base um material biológico reduzido.Members of Acanthobothrium (Eucestoda: Tetraphyllidea: Onchobothriidae) are mainly parasites marine elasmobranchs throughout the oceans. However, few lineages are found in freshwater stingrays of the family Potamotrygonidae, which members are restricted to the Neotropic. The recognition of taxonomic units involved in a host/parasite system is essential for comparative studies so that the diversification process resulting from historic associations can be accurately elucidated. Currently, 175 species are recognized for the genus, but only six parasite potamotrygonids (A. terezae, A. quinonesi, A. amazonensis, A. regoi, A. ramiroi e A. peruviense). Historically, most species of Acanthobothrium, including freshwater ones, has been described based on a restricted number of specimens from distant localities and few potamotrygonid species. This practice has led researchers to describe new species based on the premises that those lineages present low morphological variation. In this study, 649 host specimens were examined, representing 10 species and 14 morphotypes of potamotrygonids from 10 river sub basins of South America. Only five Acanthobothrium species were recognized as valid for the freshwater system, Acanthobothrium terezae (synonym A. ramiroi), A. quinonesi (synonyms A. regoi and A. peruviense), A. amazonensis and two new species A. sp. n.1 and A. sp. n. 2. These five species of Acanthobothrium parasite 27 species of potamotrygonids in almost all river basins of South America, presenting a distinct host specificity pattern from their marine counterparts. The differences in the diversity patterns observed for marine and freshwater lineages could be due to inadequate sampling of monophyletic marine groups and/or to the lack of concern with obtaining a representative number of specimens attributed to one species (host or parasite). New sources of data (e.g., molecular) are necessary to better understand the limits of the present taxonomic status of freshwaters species of Acanthobothrium. Another recommendation to access morphological variability of tetraphyllideans is to increase the sample size to different areas and hosts. Meaningful biogeographical representation is fundamental to the comprehension of biodiversity. Systematists working on the taxonomy of tetraphyllideans should also be cautious when using morphometric and meristic characters to distinguish species, which are described based on reduced biological material.
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Luchetti, Natalia da Mata. « Revisão taxonômica do gênero Potamotrygonocestus Brooks & ; Thorson, 1976 (Eucestoda : Tetraphyllidea) ». Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-18012012-093037/.
Texte intégralRésumé :
Membros do gênero Potamotrygonocestus (Eucestoda: Tetraphyllidea: Onchobothriidae) são parasitas exclusivos de raias da família Potamotrygonidae, endêmica da região Neotropical. Atualmente, são reconhecidas 7 espécies nominais para o gênero (P. magdalenensis, P. travassosi,P. amazonensis, P. maurae, P. fitzgeraldae, P. chaoi e P. marajoara), além de duas linhagens não descritas terem sido apontadas na última revisão taxonômica disponível. A taxonomia destes parasitas é tradicionalmente baseada em caracteres morfométricos e sofre com a plasticidade que a estrutura corpórea destes animais apresenta pois acaba dependente da fixação do espécime. Somada à prática comum de basear descrições em um número restrito de espécies coletados em regiões geograficamente isoladas, esta plasticidade corpórea resultou na premissa que estes parasitas apresentam baixa variabilidade morfológica. Neste estudo, foram analisados 1753 espécimes de Potamotrygonocestus, coletados amplamente na América do Sul. A análise dos parâmetros morfométricos tradicionalmente utilizados na taxonomia do gênero não mostrou utilidade na diagnose das espécies, porém os parâmetros discretos observados na morfologia do gancho mostraram-se informativos. Os ganchos são estruturas esclerotizadas cuja forma não depende da fixação do espécime, portanto possuem um enorme potencial para a resolução taxonômica destes parasitas. Baseadas na morfologia do gancho, as espécies de Potamotrygonocestus válidas foram redescritas e 4 novas linhagens foram observadas. Dentre todos os táxons observados, apenas P.chaoi e P. marajoara ainda necessitam o refinamento de sua diagnose, pois não foi possível diferenciá-los através da morfologia do gancho. Assim, uma nova chave de identificação foi proposta para Potamotrygonocestus, baseada nos caracteres discretos dos ganchos. Entre os 32 morfotipos de potamotrigonídeos amostrados neste estudo, em apenas 5 não havia infestação por Potamotrygonocestus. Estes hospedeiros restringem-se as regiões dos rios Madeira e Purus e a P. leopoldi no Xingu. Os padrões de especificidade estrita observados para grupos marinhos que se julga serem próximos a Potamotrygonocestus não se refletem no grupo dulcícola, e inclusive mais de uma espécie do gênero foi encontrada em um mesmo indivíduo hospedeiro, fato até então inédito para o gênero.The members of the Potamotrygonocestus genus (Eucestoda: Tetraphyllidea: Onchobothriidae) are parasites that infect exclusively the stingrays of the family Potamotrygonidae, which are endemic of the Neotropical region. To date, seven species are recognized for this genus (P. magdalenensis, P. travassosi, P. amazonensis, P. maurae, P. fitzgeraldae, P. chaoi and P.marajoara) and two undescribed lineages were cited in the last taxonomic revision published. The taxonomy of these parasites is traditionally based on morphometric characters and therefore relies on soft tissue structures whose observed morphology is highly dependent on the fixation method used. This, in addition to the use of a restricted number of specimens from distant localities on taxonomic studies, led researchers to believe in a low morphological variation for the genus. In this study, 1753 Potamotrygonocestus specimens were examined from almost all of the South American basins. The traditional morphometric parameters for the genus taxonomy were not useful for species diagnosis, but the discrete parameters from the morphology of the hooks were shown to be informative characters. The hooks are sclerotized structures and its shape is not dependent on the fixation of the specimen, therefore having a great potential to distinguish species. Based on the morphology of the hooks, the Potamotrygonocestus nominal species that were recognized were redescribed and four new lineages were found. Among all the taxa examined, only P. chaoi e P. marajoara still need a detailed diagnosis, because it was not possible to distinguish these two species based on the morphology of the hooks. Based on the data at hand, an inference key for species of Potamotrygonocestus is proposed based on the morphology of the hooks. Among the 32 potamotrygonids morphotypes obtained for this study, only five were not infected by Potamotrygonocestus. These hosts were restricted to the Madeira and Purus basins and for P.leopoldi from the Xingu River. The host-specificity observed for the parasite worms of marine elasmobranchs closely related to Potamotrygonocestus were nor found in this freshwater genus Additionally, more than one species of Potamotrygonocestus were found infecting the same host specimen, an occurrence never noted for this parasite taxon.
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Costa, Lisa D´Alva Sousa Nascimento. « Avaliação da sensibilização às fontes alergénicas mais comuns em associação com a prevalêcia parasitária em cães ». Master's thesis, Universidade de Évora, 2019. http://hdl.handle.net/10174/26455.
Texte intégralRésumé :
A presente dissertação está dividida em quatro partes: um capítulo sumário de
parasitologia; os princípios básicos da alergologia veterinária; os princípios gerais da
imunoalergologia e da imunoparasitologia; o estudo realizado de avaliação da sensibilização a
ácaros do pó e de armazenamento, através da realização de testes intradérmicos, que permitiram
a identificação de correlações de pares para os diferentes ácaros e correlações para os achados
diagnósticos parasitológicos num grupo de 20 canídeos, tendo em conta as relações imunitárias
estabelecidas.
Obteve-se uma prevalência de infeção parasitária geral de 50%, 10% de
ancilostomatídeos, 5% de Trichuris vulpis, 15% de Dipylidium caninum (métodos coprológicos),
15% de Hepatozoon canis, 15% de microfilarémia (citologia de esfregaço sanguíneo) e 20% de
Rhipicephalus sanguineus.
Estatisticamente foi demonstrada a correlação positiva entre sensibilização a ácaros
domésticos e prevalência de protozoários e ixodídeos, e negativa para a prevalência de infeção
por helmintes (r = -0,7; p <0,001); Abstract:
Evaluation of sensitization to the most common allergen sources in association
with parasitic prevalence in dogs
The current graduation thesis is composed of four parts: a parasitology overview; basic
principles of veterinary allergology; immunoallergology and immunoparasitology theoretical
framework; the assessment of skin reactivity with intradermal testing against a group of house
dust and forage mites, that allowed a pair correlation between the mites and a correlational
research for the parasitological findings in a group of 20 dogs, considering the immune system
relationships.
The parasite prevalence in the group was 50%, 10% of ancylostomatoids, 5% of Trichuris
vulpis, 15% of Dipylidium caninum (coprological methods), 15% of Hepatozoon canis, 15% of
microfilaremia (blood smear cytology) and 20% of Rhipicephalus sanguineus.
Positive correlation was found between positivity for dust and forage mites, protozoa and
ixodidae, and negative correlation for helminth (r = -0,7; p <0,001).
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Olego-Fernandez, S. « A calpain-like multigene family in Trypanosoma brucei ». Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:5256ea6f-4da0-4d42-b77c-a0d2da6f3af2.
Texte intégralRésumé :
Trypanosomatid parasites are unicellular eukaryotes characterised by the presence of a subpellicular array of microtubules, a single flagellum, and a kinetoplast (containing the condensed mitochondrial DNA). The majority of trypanosomatid species undergo complex life-cycles, alternating between a mammalian host and an insect vector. Progression through this life-cycle requires the differentiation of trypanosomatids into distinct, niche adapted developmental forms. Differentiation into each life-cycle stage involves important biochemical and morphological changes, including the remodelling of the subpellicular cytoskeleton that defines cell shape. In higher eukaryotes, proteins from the calpain superfamily are involved in developmentally- and environmentally-regulated remodelling of the cytoskeleton and the dynamic organisation of signal transduction cascades. Interestingly, trypanosomatids contain unusually large families of calpain-related proteins, but there is little knowledge about the functional roles of these molecules during the life-cycle of trypanosomatid parasites. In this thesis, I present the results of the bioinformatic analysis of calpain-like proteins in three trypanosomatid parasites, Trypanosoma brucei, Leishmania major and Leishmania infantum. From this analysis, I selected several calpain-related proteins tor RNAi functional analysis, on the bases of their domain composition and conservation across different species. The detailed analysis of the resulting RNAi phenotypes revealed the essential function of some calpain-like proteins for the correct morphogenesis of specific developmental forms of T. brucei, shedding some light on the mechanisms that regulate this parasite differentiation and cytoskeletal remodelling, and providing new putative therapeutic targets for African sleeping sickness.
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Mueller-Graf, Christine D. M. « Ecological parasitism of baboons and lions ». Thesis, University of Oxford, 1994. https://ora.ox.ac.uk/objects/uuid:ffd4ddb0-fbef-4be8-803f-cb3578f7e7e0.
Texte intégralRésumé :
This thesis investigates the epidemiology of intestinal parasites in wild populations of two social animals, olive baboons (Papio anubis) in Gombe Stream National Park, Tanzania, East-Africa, and lions (Panthera leo) in the Serengeti and Ngorongoro-Crater, Tanzania. These populations have been observed for over 20 years and detailed information on individual hosts was available for analysis with the parasitological data allowing to address questions about the relationship of host genetics and social behaviour to parasite infection. The baboons were infected with seven different helminths as well as two types of protozoans. Fifteen morphologically different parasites were found in the lions. All baboons and almost all lions were parasitized. Parasite distribution in both host species was overdispersed. Spatial differences in parasite infection in the baboons and lions emerged as the strongest effect on heterogeneity of infection. Parasites of both host species showed seasonal and temporal variation. Parasite-parasite associations did not appear to have a strong impact on overall patterns of infection in either baboons or lions. Across all parasite taxa, age (with one exception in baboons), sex, reproductive status and group size had little significant influence on parasite burden. For baboons age-prevalence and age-severity profiles resembled those for the same parasites in humans. Correlations between baboon social rank and parasite burden were equivocal. Parasite infection was not correlated with size of baboon female genital swelling. Two lion populations were compared, an inbred and an outbred. Only one parasite, Spirometra spp., had a significantly higher prevalence in the inbred population, contrary to expectations. Results of this study suggest that any effects on levels of infection in these wild populations due to social behaviour, genetics, sex and reproductive effort may be masked by the stronger influence of environmental and/or behavioural components of exposure, at least in the short term. This implies that the importance of factors such as genetics or social behaviour on infection may not always be apparent and may be dependent on the details of the local ecology of both host and parasite at the time the system is studied.
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Pilar, Ana Victoria. « Biochemical and molecular characterization of the glycosomal PTS2 import receptor peroxin 7 in «Leishmania donovani» ». Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32255.
Texte intégralRésumé :
The Leishmania peroxin 7 (LmPEX7 or LdPEX7) is the receptor that translocates PTS2 signal-containing proteins into the glycosome. This microbody is unique to and crucial for the survival of trypanosomatids which include Leishmania and Trypanosoma, the causative agents of leishmaniasis and African sleeping sickness, respectively. Proteins are imported into the glycosome via two pathways, PTS1 and PTS2, which involves the formation of a PTS-receptor complex in the cytosol, docking of the complex on a translocation apparatus on the glycosomal membrane, and subsequent release of the cargo protein into the lumen. However, the precise steps in glycosome protein trafficking are not well-defined and to understand the function of these organelles and prove their potential as chemotherapeutic targets, the mechanism of glycosome biogenesis needs to be fully elucidated. Not much is known about the mechanism of PTS2 import pathway in glycosomes as studies on PEX7 have been hampered by the difficulty in expressing a soluble recombinant form of this receptor. To dissect the PTS2 import pathway and to determine the role of PEX7 in Leishmania, this protein was cloned and characterized. LmPEX7 is a ~41 kDa protein containing six conserved WD40 motifs that displays limited sequence similarity to PEX7 homologues involved in the biogenesis of evolutionarily-related peroxisomes found in other eukaryotes. LmPEX7 interacts with PTS2 proteins, the PTS1 receptor LdPEX5, and the membrane-associated docking protein LdPEX14. These interactions, characterized through various biochemical techniques, were mediated by specific binding domains, formation of stable protein-protein complexes, and conformLa péroxine Leishmania 7 (LmPEX7 ou LdPEX7) est un récepteur qui transloque les protéines qui contiennent le signal PTS2 dans le glycosome. Ce glycosome est unique et critique aux trypanosomes, tels que Leishmania et Trypanosoma, les agents causant la leishmaniose et la maladie Africaine du sommeil. Les protéines sont importées vers le glycosome par deux voies, PTS1 et PTS2, qui nécessitent la formation d'un complexe PTS dans le cytosol, l'amarrage du complexe sur un appareil de translocation sur la membrane du glycosome, et permet la liberation de la charge protéique dans le lumen. Par contre, les étapes précises dans l'acheminement de protéines glycosomales ne sont pas bien définies et pour comprendre les fonctions de ces organelles et prouver qu'elles être des cibles chimiothérapiques, les mécanismes impliqués dans la biogenèse doivent être très bien élucidés. Pour disséquer le mécanisme d'importation et pour déterminer le rôle de PEX7 chez Leishmania, cette protéine a été clonée à partir de l'ADN génomique de L. major et a été caractérisée. LmPEX7 est une protéine d'environ 41 kDa qui démontre une homologie limitée aux PEX7 impliqués dans la biogenèse des peroxysomes chez autres eucaryotes. LmPEX7 interagit avec les protéines PTS2, le récepteur PTS1 LdPEX5, ainsi que la protéine LdPEX14 qui est associée à la membrane du glycosome. Ces intéractions, décrites en utilisant des techniques biochimiques variées, sont arbitrés par des domaines d'interactions situés sur LdPEX5 et LdPEX14, la formation de complexes protéiques stables, et associée à divers changements conformationnels. Des études de localisation subcellula
37
Geukers, Karen. « Characterization of CFF in the sera of plasmodium-infected mice ». Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104816.
Texte intégralRésumé :
The objective of this study was to further characterize the inhibitory serum protein crisis form factor, or CFF, and identify candidate proteins responsible for CFF activity. Four models for serum CFF induction were tested: C57BL/6 mice infected with P. chabaudi adami AS, C57BL/6 mice inoculated with BCG + LPS, and BALB/c mice infected with P. chabaudi adami DS or DK. C57BL/6 mice infected with P. chabaudi adami AS produced sera with the most pronounced level of inhibitory activity and were used for CFF analysis. Heat inactivation did not affect CFF activity, indicating the observed effect was not due to complement proteins, function was lost after heating serum to 100°C. Gel filtration determined that CFF may be in the range of 20 kDa – 80 kDa. Serum depletion by IgY retained CFF activity in the low abundance protein fraction (LAP), which was analyzed by MALDI and LC-QToF mass spectrometry and compared to the LAP from naïve mice. A total of 68 proteins were identified as either up-regulated or unique to the CFF serum, and qualitative analysis revealed one potential CFF candidate: neutrophil gelatinase-associated lipocalin. In conclusion, we have established a model for inducing serum CFF, characterized some of its physical properties, and through proteomic analysis identified a potential CFF candidate.L'objectif de cette étude visait d'une part à approfondir la caractérisation du facteur de la forme de crise (CFF; « crisis form factor »), un facteur protéique inhibiteur présent dans le sérum, et d'autre part à identifier des protéines candidates responsable de l'activité de CFF. Quatre modèles murins d'induction sérique du CFF ont été testés: des souris C57BL/6 infectées par la souche de P. chabaudi adami AS, des souris C57BL/6 inoculées avec BCG + LPS, et des souris BALB/c infectées respectivement avec les souches de P. chabaudi adami DS ou DK. L'activité inhibitrice la plus prononcée a été observé à partir du sérum prélevé chez les souris C57BL/6 infectées par la souche de P. chabaudi adami AS. Le sérum issu de ce modèle a donc été utilisé pour la suite des analyses de CFF. Nous avons déterminé que l'activité de CFF ne provient pas des protéines du complément et que CFF est inactivé lorsque le sérum est bouilli à 100oC. Le fractionnement du sérum par chromatographie d'exclusion nous a permis de déterminer que CFF est éluée dans les fractions protéiques allant de 20 kDa à 80 kDa. Le sérum a ensuite été soumis à une colonne d'affinité IgY afin d'y dépléter les protéines majoritaires. Suite à cette déplétion, nous avons déterminé que l'activité de CFF est préservée uniquement dans la fraction contenant les protéines sériques de faible abondance (LAP; « low abundance protein »). Nous avons donc analysé la fraction LAP du sérum induit pour CFF par spectrométrie de masse de type MALDI et LC-QToF, puis comparé son profil protéique à celui de la fraction LAP de sérum issu de souris naïves. Ces profils protéiques révèlent qu'un total de 68 protéines sont soit surexprimées, soit exclusives au sérum démontrant une activité CFF. De plus, l'analyse qualitative nous a permis d'identifier une protéine candidate potentiel pour CFF : la gélatinase de neutrophile associée à la lipocaline (NGLA; « neutrophil gelatinase-associated lipocalin »). En concluant, nous avons établi un modèle d'induction sérique de CFF, avons caractérisé certaines de ses propriétés physiques et avons identifié, par l'entremise de la protéomique, NGLA en tant que candidate potentielle de CFF.
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El-Shehabi, Fouad. « Characterization of novel biogenic amine receptors in the human bloodfluke «Schistosoma mansoni» ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86610.
Texte intégralRésumé :
The genome of the human bloodfluke Schistosoma mansoni encodes 18 putative biogenic amine-like G-protein-coupled receptors (GPCRs). These receptors are potential targets for the development of antischistosomal drugs. One of these sequences, SmGPR-1 (formerly SmGPCR), was previously cloned and was identified as a histamine receptor. In this study, we expanded the functional analysis of SmGPR-1 by studying its expression and tissue distribution both at the RNA and protein levels in different developmental stages of the parasite. In the second part of the study, we cloned and characterized two structurally related receptors, named SmGPR-2 and SmGPR-3. Bioinformatics analyses showed that the three receptors are members of a new clade of biogenic amine GPCRs and are characterized in part by the absence of a highly conserved aspartate (Asp3.32) of the third transmembrane domain. Like SmGPR-1, our first cloned receptor, SmGPR-2, was activated by histamine and its developmental expression at the mRNA level was similar to that of SmGPR-1, both receptors being upregulated in young schistosomula. However, their tissue localization was different. SmGPR-1 was enriched in the tegument, subtegumental musculature and the suckers, whereas SmGPR-2 was associated with neurons of the subtegumental plexuses. The distribution of these receptors correlated with that of histaminergic neurons, which were also detected in the subtegumental neuronal plexuses, the innervation of the suckers, elements of the central nervous system and transverse commissures. These studies suggest that histamine is an important neurotransmitter system in schistosomes. The third receptor investigated in this study, SmGPR-3, was not responsive to histamine but rather was found to have broad specificity for catecholamines, particularly dopamine and related metabolites. In vitro assays of cultured schistosomula revealed that many of the ligands that interact with SmGPR-3 also have strong effects on larval motilitAu génome de Schistosoma mansoni, un parasite sanguin de l'homme, on retrouve 18 récepteurs putatifs à amine biogène couplés aux protéines G (RCPG). Ces récepteurs ont un potentiel thérapeutique contre les infections aux schistosomes. La séquence SmGPR-1 (anciennement SmGPCR) a déjà été clonée et identifiée comme un récepteur à l'histamine. Une analyse fonctionnelle plus poussée de SmGPR-1 est l'objet de cette thèse. L'analyse de taux d'ARNm et de protéines à différents stades de développement du parasite a servi à l'étude de l'expression et la répartition tissulaire de SmGPR-1. Deux récepteurs similaires, de par leur structure, le SmGPR-2 et le SmGPR-3 ont été identifiés, clonés et caractérisés lors de cette étude. Suite à des analyses bioinformatiques, ces trois récepteurs ont révélé leur appartenance à une nouvelle variante de récepteurs à amine biogène couplés aux protéines G caractérisés par l'absence d'aspartate conservé (Asp3.32) dans le troisième domaine transmembranaire. Tout comme SmGPR-1, le récepteur SmGPR-2 est activé par l'histamine, et l'expression de l'ARNm est similaire à celle de SmGPR-1, les deux récepteurs étant régulés à la hausse chez les jeunes schistosomes. Toutefois, ils sont localisés à différents endroits, SmGPR-1 se retrouve dans le tégument, la musculature subtégumentaire et les ventouses, tandis que SmGPR-2 est associé aux plexus nerveux subtégumentaires. La localisation de ces récepteurs est similaire à celle des neurones histaminergiques que l'on retrouve dans les plexus nerveux subtégumentaires, l'innervation des ventouses, dans certains éléments du système nerveux central et les commissures transversales. Il semblerait que l'histamine soit un important système neurotransmetteur du schistosome. Le troisième récepteur identifié, SmGPR-3, n'est pas activé par l'histamine, mais semble démontrer une spécificité étendue aux catécholamines et tout particuli
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Sen, Rajashree. « Structure-function analysis of RNA editing ligases and their interacting protein partners in the editosome complex of «Trypanosoma brucei» ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95053.
Texte intégralRésumé :
Trypanosoma brucei is a parasite that causes the vector-borne disease African sleeping sickness. The mitochondrial mRNAs of T. brucei undergo post-transcriptional RNA editing to make mature, functional mRNAs. The final step of this process is catalyzed by the essential ligase, Kinetoplastid RNA Editing Ligase 1(KREL1) and closely related KREL2. This study is an in vitro characterization of interaction of KREL1 and KREL2 with binding partners KREPA2 and KREPA1, respectively, using full-length, truncated and point-mutated ligases. We have shown a strong, specific stimulatory effect of the interacting partners on catalytic activity of the ligases. We have narrowed the region of contact to fifty-nine C-terminal residues for KREL1 and forty-five for KREL2. Finally we have identified the N-terminal residues F206, T264 and Y275 and C-terminal K405 on KREL1 as critical for catalytic activity as well as interaction with KREPA2. K424 and the KWKE (441-444) stretch possibly co-ordinate KREPA2 interaction during adenylylation.Trypanosoma brucei est un parasite responsable en Afrique de la maladie du sommeil, une maladie à transmission vectorielle. Les ARNm mitochondriaux de T. Brucei subissent l'édition de l'ARN au niveau post-transcriptionnel pour produire des ARNm matures et fonctionnels. L'étape finale de ce processus est catalysée par la ligase essentielle KREL1 (Kinetoplastid RNA Editing Ligase 1) et celle étroitement liée, KREL2. Cette étude est une caractérisation in vitro de l'interaction de KREL1 et de KREL2 avec les partenaires de liaison KREPA2 et KREPA1 respectivement, en utilisant les séquences complètes, tronquées et mutées des ligases. Nous avons montré un effet stimulateur spécifique prononcé des partenaires interagissant, sur l'activité catalytique des ligases. Nous avons rétréci la région de contact à cinquante neuf acides aminés à l'extrémité C-terminale pour KREL1 et quarante cinq pour KREL2. Finalement, nous avons identifié les acides aminés F206, T264 et Y275 à l'extrémité N-terminale et K405 à l'extrémité C-terminale de KREL1 comme crucial pour l'activité catalytique aussi bien que pour l'interaction avec KREPA2. Les acides aminés K424 et KWKE (441-444) s'étendent éventuellement pour coordonner l'interaction de KREPA2 au cours de l'adénylation.
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Rao, Vijayaraghava. « Characterization of novel ligand-gated chloride channel subunits from «Haemonchus contortus» ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95130.
Texte intégralRésumé :
Ligand-gated chloride channels (LGCCs) are key components that form the inhibitory neurotransmission system in animals. Nematodes possess LGCCs that are gated by unique ligands such glutamate, serotonin and acetylcholine. Higher living forms such as mammals are not known to possess similar receptors. Hence nematodes can be deemed to comprise a phylum with a divergent inhibitory neurotransmission system. Based on this premise, the current project aimed to better understand the inhibitory nervous system of the parasitic nematode, Haemonchus contortus through the characterization of novel LGCC subunits and the localization of relevant ligands believed to function as inhibitory neurotransmitters. The first novel LGCC subunit gene to be isolated was named Hco-GGR-3 (previously named as HcGGR3). Electrophysiological analyses of this subunit in Xenopus laevis oocytes revealed the homomeric assembly of the channel which was predominately gated by dopamine (DA). Immuno-staining of H. contortus adult worms using antibodies raised against a peptide exclusive to Hco-GGR-3 showed that this subunit localized to deirid (cervical papilla) socket and sheath cells. Gender specific differences in localization of this subunit were also observed. In addition, a single nucleotide polymorphism located in the 3' untranslated region (UTR) of Hco-ggr-3 was found to be associated with the selection for resistance towards macrocyclic lactones (MLs) moxidectin (MOF) and ivermectin (IVM) in H. contortus. A second amine-gated chloride channel gene called Hco-lgc-55 was also isolated. Electrophysiology of this subunit revealed that this channel was gated mainly by tyramine (TA) [EC50 5.8 ± 1.0 μM (n=5)] and a lesser extent by dopamine (DA) and octopamine (OA). Semi-quantitative reverse transcription polymerase chain reaction (SqRT-PCR) showed the presence of mRNA for Hco-lgc-55 in all the life-cycle stages of the parasite. A detailed examination of the localization and characterization oLes canaux chlorures ligand-dépendants (CCLDs) sont la composante clef du système d'inhibition de la neurotransmission chez les animaux. Les nématodes possèdent des CCLDs qui sont activés par des ligands uniques tels que le glutamate, la sérotonine et l'acétylcholine. Les mammifères ne possèdent pas ce type de récepteurs. Il est possible d'émettre l'hypothèse que le phylum des nématodes a un système d'inhibition de la neurotransmission divergent. Basé sur cette caractéristique, le projet a pour objectif de mieux comprendre le système nerveux inhibiteur chez le nématode parasite, Haemonchus contortus, en caractérisant de nouvelles sous-unités de CCLD, et en localisant des ligands valables, connus pour fonctionner comme neurotransmetteur inhibiteur. La première nouvelle sous-unité du gène de CCLD à avoir été isolée, a été appelé Hco-GGR-3 (précédemment nommé HcGGR3). Les analyses électrophysiologiques de cette sous-unité, réalisées dans les ovocytes de Xenopus laevis, ont permis d'identifier un assemblage homomérique de ce canal qui est majoritairement dépendant de la dopamine (DA). L'immunocoloration de vers adultes d'H. contortus, faite à partir d'anticorps spécifiques à un peptide exclusif à Hco-GGR3, a permis de montrer que cette sous-unité était localisée au niveau des ports des deirids (papille cervicale) et des cellules de gaines. Il a été aussi observé qu'il y avait une différence de localisation de cette sous-unité en fonction du genre des vers. De plus, un polymorphisme mononucléotidique au niveau de la région 3' non transduite (UTR) de Hco-ggr3 s'est avéré être associé à une sélection pour la résistance aux lactones macrocycliques (LM) - la moxidectine (MOF) et l'ivermectine (IVM) - chez H. contortus. Un second gène d'un canal chlorure dépendant d'un acide aminé appelé Hco-lgc-55 a aussi été isolé. L'électrophysiologie de cette sous-unité a permis de montrer que ce canal était maj
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Rioux, Marie-Claire. « A study of the proteomics of fasciolosis ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106286.
Texte intégralRésumé :
Fasciolosis is an economically important veterinary parasitic disease. Of the two causative agents, Fasciola hepatica and Fasciola gigantica, F. hepatica has a greater ability to effectively establish a primary infection and resist the host defences. Certain host species, such as cattle, are more resistant to reinfection than others, such as sheep. In order to gain a greater understanding of the host response to infection, proteomic analyses of sera from sheep and cattle infected with F. hepatica were undertaken. Twenty-six indicators of infection were validated by SELDI-TOF mass spectrometry (MS) in sheep with a single-dose F. hepatica infection. Two of these markers were identified and their increase in the chronic stage of infection was validated using Western blot analysis. SELDI-TOF MS profiling of sera from trickle-infected cattle did not provide descriptive information, but tandem MS analysis of immunodepleted sera provided a more descriptive view of the host-parasite interaction. This technique was sufficiently sensitive to detect markers of inflammation during the acute stage of infection and markers of liver fibrosis during the chronic stage of infection, but was not sufficiently sensitive to detect parasite proteins. Finally, the excretory-secretory products (ESP) of F. hepatica and F. gigantica were profiled. The similarities between the two species were greater than the similarities between newly excysted juveniles (NEJ) and adults. The most notable differences between NEJ and adults were the profile of proteases released and the specific isotypes released by the parasites. NEJ expressed relatively equal amounts of cathepsin L, B, and legumain, whereas adults expressed predominantly cathepsin L. NEJ- and adult-specific cathepsin L clades were identified as well as a potential F. gigantica NEJ-specific cathepsin L clade. Antioxidant defence enzyme levels were higher in adult ESP than NEJ ESP, with higher relative abundance in F. gigantica than F. hepatica. The analysis suggests that stage-specific expression and isotype diversity should be considered when developing a vaccine targeted to the early stage of infection and when studying broad-spectrum chemotherapeutic targets. These studies contribute to the understanding of the basic biology of the causative agents of fasciolosis and the use of proteomics in studying host-parasite interactions.La fasciolase est une infection vétérinaire importante. Entre les deux agents causals, Fasciola hepatica et Fasciola gigantica, f. hepatica a une meilleure capacité pour établir une infection primaire et pour résister aux défenses de l'hôte. Certaines espèces hôtes, tels que les bovins, résistent une seconde infection mieux que d'autres espèces, tels que les moutons. Afin de mieux comprendre la réaction de l'hôte pendant l'infection, des analyses protéomiques de sérums de moutons et de bovins affectés par f. hepatica ont été entreprises. Vint-six marqueurs d'infection ont été validés par spectrométrie de masse de temps de vol à désorption-ionisation laser potentialisée par surface (SM TDV-DILPS) chez les moutons avec une seule dose infectieuse de f. hepatica. Deux de ces marqueurs ont été identifiés et leur hausse dans la phase chronique de l'infection a été validée par buvardage de western. Le profil SM TDV-DILPS de bovins infectés à plusieurs reprises n'a pas fourni des détails descriptifs, mais une analyse SM en tandem de sérums immunodéplétés a fourni un portrait descriptif de l'interaction hôte-parasite. Cette technique était suffisamment sensible pour détecter des marqueurs d'inflammation pendant la phase aigüe de l'infection et des marqueurs de la fibrose hépatique pendant la phase chronique de l'infection, mais n'était pas suffisamment sensible pour détecter des protéines parasitaires. Enfin, les produits d'excrétion-sécrétion (PES) de f. hepatica et f. gigantica ont été profilées. Les deux espèces partageaient plus de similitudes que parmi les phases de juvéniles nouvellement excystés (JNV) et des adultes. Les différences les plus notables entre les JNV et les adultes étaient le profil des protéases et les isotypes de ces protéases retrouvés. Les montants de cathepsine L, B et de legumain chez les JNV étaient relativement égaux, tandis que la majorité des protéases chez les adultes étaient cathepsine L. Des clades de cathepsine L spécifiques aux JNV et aux adultes ont été identifiés ainsi qu'un clade potentiellement spécifique aux JNV de f. gigantica. Les niveaux d'enzymes antioxydants de défense dans les PES étaient plus élevés dans chez les adultes que les JNV, ainsi qu'une abondance plus élevées chez f. gigantica que f. hepatica. Ces analyses suggèrent que l'expression des protéines spécifique aux phases de développement et la diversité des isotypes devraient être considérées lors de l'élaboration d'un vaccin ciblé à un stade précoce de l'infection et lors du développement de cibles chimiothérapeutiques à large spectre. Ces études contribuent aux connaissances fondamentales des agents causals de fasciolase et l'usage d'outils protéomiques dans l'étude des interactions hôte-parasite.
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Gonzalez, Santana Bibiana. « Cysteine proteases : potential serodiagnostic reagents for human Schistosomiasis and Fasciolosis ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110691.
Texte intégralRésumé :
Schistosomiasis and fasciolosis are parasitic diseases that affect a great number of people, particularly in developing countries, and cause huge global morbidity. Diagnosis is essential for control, treatment and prognosis of the diseases and yet a simple, cheap, sensitive and specific assay is not readily available for either of them. In the current study, cathepsin B (SmCB) and cathepsin L1 (FhCL1) were investigated as potential diagnostic reagents to detect schistosomiasis and fasciolosis, respectively, in humans. The genes encoding SmCB and FhCL1 were expressed Pichia pastoris and the proteins isolated to homogeneity by affinity chromatography. The SmCB ELISA was optimized for antigen concentration, primary antibody dilution and secondary antibody dilution using a pool of sera obtained from patients that were coprologically-positive or negative for schistosomiasis. A clear distinctive was achieved between these two sera pools. However, when employed to screen a panel of patients from Senegal the test failed to provide satisfactory discrimination between schistosoma-infected and schistosoma-negative individuals. The FhCL1 ELISA was optimized using sera from Fasciola-infected individuals from Cuba, and samples from Cuban and Canadian non-infected patients. We determined the optimal dilution for the primary antibody and also assessed/compared the performance of anti-total IgG, IgG4, IgG1 and IgG2 secondary conjugated antibodies. Total IgG provided the best discrimination between Fasciola- infected and non-Fasciola infected individuals with a 99.99% sensitivity and specificity. Furthermore, by screening sera obtained from patients infected with various worm and protozoan diseases we showed that the FhCL1 ELISA does not cross-react with other diseases commonly found in similar geographical regions as fasciolosis. In conclusion, diagnosis of human schistosomiasis still remains uncertain and more studies need to be performed to improve our diagnostic test using SmCB. On the other hand, we have developed a simple, sensitive, specific and accurate test to detected human fasciolosis by using FhCL1, a major protease released by the parasite. The P. pastoris expression system allowed us to obtain up to 80 mg of FhCL1 enzyme per 4 L culture. Therefore, we not only have developed a standardized test that showed high specificity and sensitivity but we also have the methodology to obtain sufficent quantities of antigen needed future mass screening of human fasciolosis in affected regions.La schistosomiase et la fasciolose sont deux maladies parasitaires qui touchent un grand nombre de personnes, en particulier dans les pays en développement, causant une morbidité élevée. Le diagnostic est essentiel pour le contrôle, le traitement et le pronostic de ces maladies et pourtant aucun essai simple, abordable, sensible et spécifique n'est disponible à ce jour pour l'une d'entre elles. Dans le cadre de la présente étude, cathepsine B (SmCB) et cathepsine L1 (FhCL1) ont fait l'objet d'une investigation sur leur potentiel à être utiliser pour diagnostiquer la schistosomiase et fasciolose, respectivement, chez les humains. Dans la présente étude, les gènes encodant SmCB et FhCL1 ont été exprimés dans Pichia pastoris et les protéines isolées par chromatographie d'affinité. Le test ELISA pour SmCB a été optimisé pour une concentration en antigène et pour une dilution d'anticorps primaire et secondaire en utilisant un pool de sérums provenant de patients qui étaient positifs ou négatifs pour la schistosomiase suivant des examens coprologique. Une distinction claire entre ces deux bassins de sérums a été observée. Toutefois, lorsque le test a été utilisé pour dépister des patients du Sénégal, il a échoué à fournir une discrimination satisfaisante entre les individus infectés et non-infectés par la schistosomiase.Le test ELISA pour FhCL1 a été optimisé à l'aide de sérums provenant de personnes cubaines infectées par la fasciolose et de patients non-infectés de Cuba et du Canada. Nous avons déterminé la dilution optimale pour l'anticorps primaire et également évalué et comparé la performance des anticorps secondaires conjugués contre les IgG totaux, IgG4, IgG1 et IgG2. Les IgG totaux ont fourni la meilleure discrimination entre les personnes infectées et non-infectées par la fasciolose avec une sensibilité et une spécificité de 99.99 %. En plus, en appliquant le test de dépistage sur des patients infectés par d'autres variétés de vers et de protozoaires, nous avons démontré que le test ELISA pour FhCL1 ne réagit pas de façon croisée avec d'autres maladies retrouvées couramment dans les régions géographiques où se trouve la fasciolose.En conclusion, le diagnostic de la schistosomiase humaine reste encore incertain et d'autres études doivent être effectuées pour améliorer notre test de dépistage utilisant SmCB. D'autre part, nous avons développé un test simple, sensible, spécifique et précis pour le dépistage de la fasciolose humaine en utilisant FhCL1, une protéase majeure relâchée par le parasite. Le système d'expression de P. pastoris nous a permis d'obtenir jusqu'à 80 mg de FhCL1 par 4 litres de culture. Dans la présente étude, nous avons non seulement mis au point un test standardisé démontrant une spécificité et une sensibilité élevées, mais également développé une procédure pour produire de grandes quantités d'antigènes nécessaires au dépistage à grande échelle de la fasciolose humaine dans les régions touchées.
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Solomon, Jonathan. « The localization and «in vitro» detection of «Brugia malayi» secreted proteins ». Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32546.
Texte intégralRésumé :
Products excreted or secreted (ES) by parasitic nematodes may contribute to the processes of infection and tissue migration of the parasite, modulating the host immune response and host physiology. These ES products allow the parasite to persist and survive in conditions that would otherwise bar or destroy them. cDNAs encoding three known secreted proteins of Brugia malayi was cloned for expression in E. coli and subsequent protein purification. These proteins were chosen because they have been reported to be secreted and to play roles in immune evasion. These proteins include: macrophage inhibitory factor 1 (MIF-1), a tumor protein homologue (TPH-1) and a cysteine protease inhibitor (CPI-2). Antibodies were raised to all of these secreted proteins. The secreted protein CPI-2 was localized to a specific region of microfilariae of B. malayi and the basic anatomy of this parasitic stage was observed by means of confocal microscopy. The protein was found to be localized to the secretory pore, which appears to be regulated by musculature. Biotinylated Sandwich ELISAS were developed to detect these secreted proteins in cultures of two stages and both sexes of B. malayi.Les produits sécrétés ou excrétés de nématodes parasitiques pourraient contribuer aux processus d`infection et de migration dans les tissues, tout en modulant le système immunitoire et la physiologie de l`hôte. Ces produits permettent au parasite de survivre dans des conditions infavorables. Trois protéines sécrétées du nématode parasitique Brugia malayi ont été clonées et produites dans du E.coli. Celles-ci ont ensuite été purifiées. Ces protéines se trouvent à être: la macrophage inhibitory factor 1 (MIF-1), la tumor protein homologue (TPH-1) et la cysteine protease inhibitor (CPI-2). CPI-2 a été localisée dans une région délimitée de la microfilaria du B.malayi et l`anatomie de ce stage parasitaire a été observé à l`aide de la microscopie confocale. La région délimitée où cette protéine est sécrétée se trouve à être le pore sécrétoire. Le pouvoir sécrétoire de ce pore semble être contrôlé par la musculature du nématode. Des ELISAs Sandwich Biotinylés ont été développés pour détecter la présence de MIF-1, TPH-1 et CPI-2 dans les différents stages de développement du B.malayi et dans les deux sexes de ce nématode.
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Moreno, Yovany. « Characterization of secretory processes and the secretome of parasitic nematodes ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=106464.
Texte intégralRésumé :
Relatively little is known about the molecular mechanisms displayed by parasitic nematodes to infect a host; however, it has been generally recognized that successful parasitic nematode infections rely on their ability to release a variety of products commonly named Excretory-Secretory Products (ESP). To gain a deeper understanding of the mechanisms that lead to the establishment of filarial nematode infections, we collected and analyzed through 1D-SDS PAGE and LC-MS/MS the ESP of Brugia malayi adult females, adult males and microfilariae, one of the etiological agents of human lymphatic filariasis. 228 proteins were identified through this approach, including several proteins with potential immunoregulatory properties. Subsequent work using an immunohistochemical approach allowed for the definition of 3 anatomical expression patterns in B. malayi microfilariae for a representative group of 5 ESP. All of these patterns involved localization in the microfilarial Excretory-Secretory apparatus, a specialized anatomical feature involved in protein release that in this life stage was found to be associated to a muscle structure. Glutamate-gated chloride channels (GluCls), the main target of the antiparasitic drug ivermectin (IVM), were also located at this structure, suggesting that protein release from the Excretory-Secretory apparatus is enhanced by neuromuscular activity regulated by GluCls. Consistent with these observations, a marked reduction in protein release by microfilariae upon in vitro IVM exposure was shown. It is proposed that under in vivo conditions, the rapid microfilarial clearance induced by IVM treatment is the result of the suppression of the parasite's ability to secrete proteins that enable evasion of the host immune system. Finally, it is anticipated that elucidation of specific features associated with each of the different parasitic nematode lifestyles would require the comparison of ESP composition from several nematode species. To overcome the limitations associated with the lack of sequence information in most nematode species required for the database searching strategy in MS-based proteomic analysis, the use of transcriptomic next-generation sequencing (RNA-seq) de novo assemblies is explored to identify the ESP composition of the mouse gastrointestinal (GI) parasitic nematode Heligmosomoides polygyrus. 209 proteins were identified using this strategy. The list also includes proteins with potential involvement in immunoregulation, modulation of signalling pathways and nutrient transport and/or uptake. The results presented here are useful to understand the roles of proteins released by filarial and GI nematodes in immune evasion events and other aspects of the host-parasite relationship.Les mécanismes moléculaires déployés par les parasites pour s'établir dans leur hôtes sont relativement méconnus; néanmoins, il est généralement accepté que le succès des infections par les nématodes parasitaires dépend de leur capacité à libérer une variété de produits dénommés produits d'excrétion-sécrétion (PES). Afin d'acquérir une meilleure connaissance des mécanismes qui conduisent à l'établissement d'infections de nématodes filaires, nous avons recueilli et analysé par électrophorèse sur gel de polyacrylamide (1D-SDS-PAGE) et par chromatographie liquide couplée à la spectrométrie de mases ( LC-MS/MS) les PES des adultes mâles et femelles et des microfilaires de Brugia malayi, l'un des agents étiologique de la filariose lymphatique humaine. Grâce à cette approche, 228 protéines ont été identifiées, incluant plusieurs protéines possédant potentiellement des propriétés immunorégulatrices. Des travaux ultérieurs utilisant une approche immunohistochimique ont permis de définir trois profils d'expression anatomique pour un groupe représentatif de 5 PES chez les microfilaires de B. malayi. Pour tous ces profils, les protéines ont été localisées au niveau de l'appareil d'excrétion-sécrétion des microfilaires. Cette structure anatomique spécialisée est impliquée dans la libération de protéines et, chez ce stade de développement du parasite, elle est associée à une structure musculaire. Nous avons aussi montré que les canaux chloriques glutamate-dépendants (GluCls), la cible principale du médicament antiparasitaire ivermectine (IVM), étaient également localisés dans cette structure, ce qui suggère que la libération de protéines par l'appareil d'excrétion-sécrétion est renforcée par l'activité neuromusculaire régulée par des GluCls. Ces résultats concordent avec l'observation in vitro d'une réduction marquée de la libération de protéines par les microfilaires exposés à l'IVM. Il est proposé que, dans des conditions in vivo, l'élimination rapide des microfilaires induite par traitement avec l'IVM est causée par la suppression de la capacité du parasite à sécréter des protéines lui permettant d'évader le système immunitaire de l'hôte. Finalement, il est prévu que l'élucidation des caractéristiques spécifiques associées à chacun des différents modes de vie des nématodes parasitaires requerrait la comparaison de la composition des PES de plusieurs espèces de nématodes. Ces comparaisons, qui requièrent l'emploi d'une stratégie de recherche des résultats des MS générés lors des analyses protéomiques sur des banques de données des protéines, sont fortement limitées par l'absence d'information sur les séquences pour la plupart des espèces de nématodes. Pour contourner ces limitations, nous avons essayé l'utilisation des assemblages de novo du séquençage transcriptomique de nouvelle génération (RNA-seq) afin d'identifier la composition des PES du nématode gastrointestinal (GI) chez la souris Heligmosomoides polygyrus. 209 protéines ont été identifiées en utilisant cette stratégie. La liste comprend aussi des protéines ayant une implication potentielle dans l'immunorégulation, la modulation des voies de signalisation et le transport et/ou l'absorption de nutriments. Les résultats présentés dans cette thèse permettent de mieux comprendre le rôle des protéines libérées par des nématodes filaires et GI dans les événements d'évasion immunitaire et dans d'autres aspects de la relation hôte-parasite.
45
Diawara, Aïssatou. « Development of DNA assays for the detection of single nucleotide polymorphism associated with benzimidazole resistance, in human soil-transmitted helminths ». Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19242.
Texte intégralRésumé :
Soil-transmitted helminths are parasitic worms of humans, causing many disabilities in tropical parts of the developing world. Control programs such as "The Focussing Resources on Effective School Health” (FRESH) Partnership have been implemented to remove human soil transmitted nematodes through large-scale use of benzimidazole anthelmintic drugs for school-aged children in developing countries. The benzimidazole drugs, albendazole and mebendazole are used as a single annual dose in areas where the burden is high. Unfortunately, there is concern that increased use of anthelmintics in children could select for resistant populations of these human parasites. In filarial nematodes, a single amino acid substitution from phenylalanine (Phe) to tyrosine (Tyr), known to be associated with benzimidazole resistance in other nematodes, has been found in parasite ß-tubulin at position 200. We have developed pyrosequencer assays for the codon 200 in Trichuris trichiura, Ascaris lumbricoides, and the hookworm Necator americanus to screen for this single nucleotide polymorphism (SNP). Assays for this resistance-associated SNP could be useful for monitoring for anthelmintic resistance in control programs. These assays have been tested on adult worms from a benzimidazle-naïve population in Kenya. Following this, these assays have been applied on individual worms, pooled eggs and pooled larvae from people in East Africa, the Caribbean and Central America where mass drug anthelmintic programs have been implemented. The 200Tyr SNP was detected in T. trichiura from non-treated people and in T. trichiura and N. americanus from benzimidazole-treated people.Les géo-helminthes sont des vers parasitant l'Homme et causant de nombreux handicaps dans les régions tropicales des pays en voie de développement. Des programmes de contrôles tels que le partenariat FRESH : ''Focussing Resources on Effective School Health'' ont été mis en place afin d'éliminer les géo-helminthes en administrant massivement en milieu scolaire des pays en voie de développement des medicaments anthelmintiques. L'albendazole et le mébendazole appartiennent au groupe des benzimidazoles et sont distribués dans les régions grandement infestées. Cependant, cette attribution massive de médicaments, aux enfants, pourrait entraîner une sélection de parasites résistants aux anthelmintiques. La substitution de l'acide aminé phénylalanine (Phe) par la tyrosine (Tyr) connue pour être associée à la résistance aux benzimidazoles chez les nématodes a été identifiée chez les filaires à la position 200 du gène de la ß-tubuline. Nous avons développés des tests pour les parasites Trichuris trichiura, Ascaris lumbricoides et Necator americanus en utilisant la méthode du pyroséquençage afin de détecter le polymorphisme d'un unique nucleotide (SNP) au niveau du codon 200 du gène de la ß-tubuline. Ce test a été appliqué sur des vers adultes provenant d'individus du Kenya n'ayant jamais été traités par des anthelmintiques. Puis ce même test a été appliqué à des vers adultes individuels, à des pools d'œufs et de larves provenant d'individus d'Afrique de l'est, des Caraïbes et d'Amérique centrale, où les programmes de contrôles de masse sont implantés. Le SNP fût détecté chez T. trichiura provenant d'individus non-traités aux benzimidazoles ainsi que chez T. trichiura et N. ameri
46
Gomez, Gonzalez Maria. « «Leishmania»-macrophage interactions : regulations of protein tyrosine phosphatases and its implication in the outcome of infection ». Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=40736.
Texte intégralRésumé :
The outcome of Leishmania infection depends both on host and pathogen factors. Macrophages, the specialized host cell for uptake and intracellular development of Leishmania parasites, play a central role in the control of infection. Underlying their effector and accessory functions is the activation of signalling pathways, which in turn are largely controlled by events of protein phosphorylation. Consequently, the regulation of protein kinase and phosphatase activities results critical for the sequential progression of the signalling cascade, and therefore for the control of antimicrobial and inflammatory phagocyte functions. This doctoral thesis discusses novel mechanisms of protein tyrosine phosphatase (PTP) regulation in the context of Leishmania-macrophage interactions. Herein are presented two events in which, independently, host and pathogen factors orchestrate the differential regulation of macrophage PTP activity. Chapter 2 describes the role of NRAMP-1 on macrophage PTP activity modulation. These investigations led to discover that iron, a metal substrate of NRAMP-1, inhibits PTP activity, resulting in the upregulation of leishmanicidal macrophage functions, through the positive regulation of JAK/STAT and MAPK signalling. Furthering these observations, an in depth study of the mechanisms underlying iron-dependent PTP inhibition (presented as Chapter 3), identified mononuclear dicitrate iron citrate complexes as specific PTP inhibitors. Despite the role of macrophages as efficient accessory and effector immune cells, Leishmania has evolved strategies to downregulate host cell functions. This is largely mediated by the parasite-induced activation of macrophage PTPs. In Chapter 4 we identified PTP1B and TCPTP as two novel PTPs engaged upon Leishmania infection. More importantly, we unravel an intimate interaction between the Leishmania surface protease GP63 and host PTPs, revealing a novel mechanism of PTP cleavage-dependent activation. Collectively,L’issue d’une infection avec Leishmania dépend de la réponse de l’hôte ainsi que des facteurs pathogéniques. Le macrophage, la cellule hôte, est spécialisée dans l’internalisation et le développement intracellulaire du parasite Leishmania et joue un rôle clé dans le contrôle de l’infection. Les fonctions effectrices et accessoires du macrophage proviennent de l’activation des voies signalétiques, qui à leur tour sont largement contrôlées par des événements de phosphorylation de protéines. Donc, la régulation de l’activité des protéines kinases et phosphatases devient essentielle dans la progression séquentielle d’une cascade signalétique et, par conséquent, dans le contrôle des fonctions inflammatoires et antimicrobiales du phagocyte. Cette thèse doctorale propose de nouveaux mécanismes de régulation des protéines tyrosine phosphatases (PTPs) dans le cadre des interactions entre le macrophage et Leishmania. Dans cette étude, nous présentons deux événements dans lesquels des facteurs de l’hôte ainsi que du parasite influencent, de façon indépendante, la régulation différentielle de l’activité PTP du macrophage. Le Chapitre 2 décrit le rôle du NRAMP-1 dans la modulation de l’activité PTP du macrophage. Ces recherches nous ont conduits à découvrir que le fer, un métal substrat du NRAMP-1, inhibe l’activité PTP, ayant comme effet l’augmentation des fonctions leishmanicides du macrophage en régulant de façon positive les voies signalétiques JAK/STAT et MAPK. En plus de ces observations, dans une étude plus approfondi des mécanismes responsables de l’inhibition des PTPs dépendents du fer (présentées dans le Chapitre 3), nous avons identifié les complexes mononucléaires dicitrate fer citrate comme des inhibiteurs spécifiques des PTPs.Malgré le rôle central du macrophage comme cellule accessoire et effectrice du système immunitaire, Leishmania a développé des stratégies afin de ré
47
Odiere, Maurice. « Energetic, morphologic and physiologic responses during «Heligmosomoides bakeri» (Nematoda) infection and protein deficiency in pregnant and lactating mice ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95137.
Texte intégralRésumé :
This research investigated the concurrent effects of a gastrointestinal nematode infection Heligmosomoides bakeri, pregnancy, and protein deficiency (PD) during late pregnancy throughout lactation on energetic, morphologic and immunological responses in CD1 mice and their offspring. Our novel findings can be summarized broadly into three key themes: (i) energetics and resting metabolic rate, (ii) bone metabolism and (iii) immune development. This work highlights the largely independent ways in which the mouse responds to competing demands of pregnancy, infection, and PD. Pregnancy increased RMR while PD lowered RMR; a trickle infection was not associated with any change. During pregnancy, these additional energetic demands were met by increased food intake and fat utilization. During infection mice lowered their body temperature. Finally, the reduction in RMR during PD was associated with higher serum corticosterone and leptin concentrations. A second novel finding was that both infection and PD impacted on maternal and neonatal bone development. Infection lowered maternal femur bone area which was associated with elevated serum IFN-γ in heavily infected pregnant mice and reduced foetal crown-rump length consistent with higher amniotic fluid IL-1β. Lower bone mineralization in PD dams was associated with elevated serum corticosterone and leptin whereas it was associated with elevated serum IL-1β and IL-6 during infection. The elevated serum IL-1β, lower leptin and IGF-1 in pups of PD and infected dams were consistent with the shorter crown-rump length. Finally, we explored for the first time the impact of maternal PD and infection on neonatal immune development. Both maternal infection and PD reduced lymphoid organ mass in pups whereas the percentage of T cells and T:B cell ratio in the spleen was increased only by maternal PD. These changes were associated with elevated corticosterone and IL-6 concentration in milk, and lower pup serum leptin and IGF-1 iL'impact sur les réactions immunologiques, énergétiques et morphologiques a été étudié suite à une combinaison de facteurs tels une infection par Heligmosomoides bakeri, un nématode du système gastro-intestinal, la grossesse et la déficience protéique (DP) durant les derniers mois de grossesse et pendant la lactation chez les souris CD1 et leur descendance. Nos découvertes peuvent se résumer selon trois thèmes clés: (i) énergétique et métabolisme de base (MB), (ii) métabolisme osseux et (iii) développement immunitaire. Ce travail met en évidence les diverses voies indépendantes utilisées par la souris pour répondre à trois évènements: la grossesse, l'infection et la DP. La grossesse a augmenté le MB tandis que la DP l'a diminué. Une infection peu sévère n'a été associée à aucun changement. Durant la grossesse, les besoins énergétiques supplémentaires ont été comblés en augmentant l'apport nutritionnel et l'utilisation des graisses. Pendant la période d'infection, la température corporelle des souris a diminué. Enfin, la réduction du MB lors de la DP a corrélé avec une plus grande concentration de corticostérone et de leptine. Notre seconde découverte montre que l'infection et la DP ont un impact sur le développement osseux maternel et néonatal. L'infection a diminué l'os du fémur et a entraîné une forte concentration d'IFN-γ dans le sérum des souris gestantes fortement infectées. Elle a aussi diminué la distance vertex-coccyx tout en augmentant IL-1β dans le fluide amniotique. Une plus faible minéralisation osseuse chez les souris souffrant de DP coïncidait avec une forte concentration de corticostérone et de leptine dans le sérum bien qu'elle coïncidait avec une forte concentration d'IL-1β et d'IL-6 lors de l'infection. Une concentration élevée de IL-1β mais plus faible de leptine et de IGF-1 chez les souriceaux de mères infectées et souffrant de DP était compatible avec des distances$
48
Abu, Dayyeh Issa. « Alteration of macrophage signalling and functions by the protozoan parasite «Leishmania» ». Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66771.
Texte intégralRésumé :
Parasites of the genus Leishmania are able to secure their survival and propagation within their host by altering key signalling pathways involved in the ability of macrophages (MØs) to directly kill pathogens or to activate cells of the adaptive immune system. One important step in this immune evasion process is the Leishmania-induced activation of host protein tyrosine phosphatase SHP-1. SHP-1 has been shown to directly inactivate JAK2 and Erk1/2, and to play a role in the negative regulation of several transcription factors involved in MØ activation such as: NF-B, STAT-1α, and AP-1. These signalling alterations contribute to the inactivation of critical MØ functions such as the production of IFN-γ-induced nitric oxide (NO), a free radical associated with parasite killing and clearance. In addition to interfering with IFN-γ receptor signalling, Leishmania is able to alter several LPS-mediated responses (e.g. IL-12, TNF-α, NO production) through mechanisms not yet fully understood. A main goal of this study was to better understand the mechanisms used by the parasite to block Toll-like receptor (TLR)-mediated functions. Experiments performed revealed a pivotal role for SHP-1 in the inhibition of TLR-induced MØ activation through binding to and inactivating IL-1 receptor-associated kinase 1 (IRAK-1). We identified the binding site as an evolutionarily conserved ITIM-like motif, which we named kinase tyrosine-based inhibitory motif (KTIM). Further experiments and sequence analysis revealed that several cytosolic kinases other than IRAK-1 possess potential KTIMs, suggesting it could represent a regulatory mechanism widely used by kinases. The final experimental section aimed to explore the differential ability of the two different stages of Leishmania, promastigotes and amastigotes, to alter MØ signalling and function. In conclusion, this work uncovers a new mechanism whereby Leishmania is ableLes parasites du genre Leishmania assurent leur survie et leur propagation par l'altération de voies de signalisation impliquées dans la capacité des macrophages (MØs) à détruire directement les pathogènes ou à activer les cellules du système immunitaire acquis. Une étape critique de ce mécanisme d'inactivation est l'activation par Leishmania de la protéine phosphatase SHP-1 de la cellule hôte. Il a été démontré que la protéine SHP-1 peut inactiver directement JAK2 ainsi que Erk1/2 et joue un rôle dans la régulation négative de plusieurs facteurs de transcription, tels que NF-κB, STAT-1α et AP-1, impliqués dans l'activation des MØs. L'altération de ces voies de signalisation contribue à l'inactivation de fonctions critiques des MØs telle que la production d'oxyde nitrique (NO) induite par l'IFN-γ, un radical-libre impliqué dans l'anéantissement du parasite. En plus d'inhiber les fonctions engendrées par l'IFN-γ, Leishmania est capable d'inhiber de nombreuses fonctions induites par le LPS, incluant la production d'IL-12, de TNF-α et de NO, et cela par des mécanismes encore peu compris. Le but principal de cette étude était de mieux comprendre les stratégies employées par le parasite afin d'inhiber les fonctions induites par les Toll-like receptors (TLRs). Nos résultats révèlent le rôle critique de SHP-1 dans l'inhibition de l'activation des MØs induite par les TLRs, par l'interaction et l'inactivation de la kinase 1 associée au récepteur IL-1 (IRAK-1). Nous avons également identifié le site de liaison qui semble être un motif conservé lors de l'évolution ressemblant à un ITIM, que nous avons nommé motif de kinase à base de tyrosine inhibiteur (KTIM). Des expériences supplémentaires et l'analyse de séquences ont révélées que plusieurs autres kinases cytosoliques autres qu'IRAK-1 possèdent un motif potentiel KTIMs, suggérant que le KTIM pourrait$
49
McLean, James. « Purification and characterization of the Leishmania PTS2 receptor, Peroxin 7, an essential receptor for glycosme biogenesis ». Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110401.
Texte intégralRésumé :
The trypanosomatid parasite Leishmania infects 12 million people in tropical countries. This neglected tropical disease causes debilitating and often fatal consequences in the absence of chemotherapeutic intervention. Consequently, there is a need to identify new drug targets to combat the increasing incidence of resistance to current treatments. An attractive drug target in these parasites is the glycosome, a unique microbody organelle that compartmentalizes several essential enzymatic pathways behind an impermeable membrane. The Leishmania major Peroxin 7 (LPEX7) is a receptor protein that recognizes glycosomal matrix proteins containing an N-terminal peroxisomal targeting signal 2 (PTS2) and facilitates the trafficking of these proteins across the glycosomal membrane. Genetic studies in the related trypanosomatid parasite, Trypanosoma brucei, have demonstrated that PEX7 is essential for parasite viability. LPEX7 is predicted to have a hydrophobic outer surface which has made production of this recombinant protein in the E. coli heterologous system challenging. LPEX7 was successfully purified in the presence of non-ionic detergents, however, this limited the usefulness of this protein in regards to downstream in vitro studies with glycosomal membranes. To investigate the biophysical role of LPEX7 in the trafficking and import of proteins into the glycosome, we have developed a strategy to reliably express and purify recombinant Leishmania PEX7 in the absence of detergents. Subsequent biochemical studies confirmed that the recombinant LPEX7 was functionally active and, like the native protein or detergent purified protein, binds LdPEX5 and PTS2 cargo proteins with nanomolar affinities. Initial investigations of the quaternary structure demonstrated that LPEX7 is in equilibrium between a dimer and tetramer in solution. Preliminary protein-protein interaction domain mapping studies have demonstrated that the C-terminal half LPEX7 was sufficient to bind both LdPEX14 and LdPEX5.Le parasite trypanosomatide Leishmania affecte plus de 12 millions d'individus dans les pays tropicaux. Cette maladie tropicale négligée a de graves conséquences, parfois fatales, en absence d'interventions thérapeutiques. Il y a, par conséquent, urgence d'identifier de nouvelles cibles thérapeutiques pour combattre ce fléau et restreindre l'incidence de résistance envers les médicaments présentement employés. Une cible thérapeutique de choix s'est révélée récemment dans cette famille de parasite. Il s'agit du glycosome, un organelle qui compartimente plusieurs voies métaboliques derrière une membrane imperméable. La Péroxine 7 de Leishmania major (LPEX7) est un récepteur cytosolique qui reconnaît certaines protéines destinées pour le glycosome contenant un signal peptidique de type 2 (PTS-2) à leur terminal N et qui facilite le transport vers la membrane du glycosome. Récemment, des études génétiques sur le parasite trypanosomatide Trypanosoma brucei ont démontré que PEX7 est essentiel pour la survie du parasite. Des prédictions bio-informatiques révèlent que LPEX7 contient une surface extérieure hydrophobe, ce qui explique le défi que représente la production de cette protéine de façon recombinante dans le système E. coli. LPEX7 fut purifiée avec succès en présence de détergents ioniques, ce qui a toutefois limité les possibilités d'études d'interactions avec des membranes. Dans le but d'étudier le rôle biophysique de LPEX7 dans le transport et l'importation de protéines vers le glycosome, nous avons développé une stratégie pour exprimer et purifier LPEX7 de façon recombinante en l'absence de détergents. Ensuite, nos études biochimiques ont confirmé que LPEX7 recombinante est active et, tout comme LPEX7 précédemment purifiée avec l'aide de détergents, est capable de lier les protéines contenant un signal PTS-2 et LdPEX5 à des concentrations nano-molaires. Une investigation de la structure quaternaire de LPEX7 a révélé que le récepteur s'assemble en dimères et tétramères en solution. Finalement, des études préliminaires d'interaction protéine-protéine ont illustré que LPEX7 contient un site d'attachement pour LdPEX5 et LdPEX14 sur la demie portion terminale C.
50
Moncada, Darcy Marie. « Entamoeba histolytica cysteine proteinases facilitate parasite invasion of the colon by disrupting the colonic mucus barrier ». Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85940.
Texte intégralRésumé :
The protozoan parasite Entamoeba histolytica is the etiological agent of human amebiasis. Trophozoites colonize the colonic mucus layer and may invade the epithelium subsequent to overcoming the mucus barrier. MUC2 is the major gel-forming mucin secreted by goblet cells in the colon and serves to maintain epithelial barrier function as well as acting as a major host defense against invading pathogens. The polymerization of MUC2 monomers via the N- and C- terminal cysteine rich D-domains is essential for mucus gel formation and confers protection to the underlying mucosa. Amoebae secrete cysteine proteinases, glycosidases and an unidentified mucus secretagogue, which may play a role in overcoming the protective mucus barrier. We hypothesize that E. histolytica cysteine proteinases as well as glycosidases are involved in mucus degradation and weakening of the mucus barrier by disrupting mucin polymerization. Amoebae secreted cysteine proteinases were shown to degrade the cysteine rich regions of MUC2 involved in polymerization and abrogate its protective function. More importantly, the major E. histolytica surface proteinase, cysteine proteinase 5 (EhCP5) was shown to specifically degrade [35S]cysteine labeled colonic mucin as effectively as secreted components. Moreover, trophozoites genetically engineered to express low levels of CP activity were incapable of traversing a mucus barrier and destroying the underlying epithelium, indicating a strong dependence between amebic invasiveness and cysteine protease activity. In addition, we have demonstrated that EhCPs specifically target the MUC2 C-terminus resulting in destabilization of the mucin polymeric network. Parasite glycosidase activity was also shown to contribute to mucin oligosaccharide degradation. Taken together, these results indicate that E. histolytica can substantially weaken the colonic mucus barrier via proteolytic degradation and glycosidase activity to compromise the gel and