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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
371

Expressão de componentes da matriz extracelular induzida por vesículas de Trypanosoma cruz liberadas no meio de cultura / Expression of extracellular matrix components by vesicles of Trypanosoma cruzi shed into the culture medium

Viviana Barbosa Paes 26 September 2008 (has links)
O Trypanosoma cruzi libera para o meio, vesículas contendo material de sua superfície e aparentemente estas vesículas seriam uma maneira de ativar e preparar a célula hospedeira para a invasão, além de induzir um aumento na expressão de alguns componentes da matriz extracelular. Neste trabalho demonstramos que essas vesículas aumentam a expressão de fibronectina na matriz, sendo este aumento dose-dependente e linear ao longo do tempo. Porém, para laminina não conseguimos observar o mesmo comportamento. Nossos resultados também mostram que os constituintes lipídicos das vesículas podem ser os responsáveis pelo aumento da expressão de fibronectina em cultura de células epiteliais. Os dois grandes grupos de glicoproteínas encontradas na superfície do parasita e nas vesículas, mucinas e Tc85 não parecem estar envolvidos no processo. As culturas celulares tratadas com os lipídeos extraídos das vesículas apresentaram um aumento de fibronectina também dose-dependente, porém, com uma resposta linear ao longo do tempo e uma expressão máxima atingida em tempos menores / Trypanosoma cruzi releases to the environment plasma membrane vesicles. Apparently, these vesicles could be a signal released by the parasite to prepare the host cell for the invasion. This study demonstrated that these vesicles induce a dosisdependent expression of fibronectin, linear over time. The same behavior has not been observed for laminin. Our results also show that lipids from the vesicles are involved in the increase of expression of fibronectin by epithelial cells. The two major surface membrane glycoproteins, Tc85 and mucins, also present in the vesicles do not participate in this phenomenon. Cell cultures that have been treated with lipids extracted from T. cruzi membrane vesicles also provoked a dosis-dependent increase in fibronectin and linear over time
372

Avaliação da participação da galectina-1 na evolução da infecção experimental aguda por Trypanosoma cruzi / Impact of galectin-1 on the evolution of acute experimental Trypanosoma cruzi infection

Thalita Bachelli Riul 11 June 2010 (has links)
A galectina-1 (Gal-1) é uma proteína que reconhece -galactosídeos e participa de vários processos biológicos, incluindo a modulação da resposta imunológica. Vários relatos da literatura reportam o potencial uso terapêutico da Gal-1 para doenças auto-imunes, inflamatórias, degenerativas e infecciosas. Entretanto, são escassos os relatos sobre o envolvimento da Gal-1 na doença causada por Tripanosoma cruzi. O presente trabalho tem como objetivos o estudo da participação da Gal-1 endógena e exógena na evolução da infecção aguda experimental por T. cruzi. Galectina-1 recombinante, camundongos C57BL/6 deficientes (nocaute - Gal-1-/-) ou não (selvagem - Gal-1+/+) do gene da galectina-1 e macrófagos desses animais foram utilizados em experimentos de infecção in vivo e/ou in vitro. Os animais foram infectados com tripomastigotas de T. cruzi da cepa Y, por via intraperitoneal. Os parâmetros analisados na caracterização do processo de infecção foram: parasitemia e sobrevivência; histopatologia do tecido cardíaco; dosagem de óxido nítrico, pelo método de Griess; imunofenotipagem de leucócitos, por citometria de fluxo; dosagem de citocinas por ELISA e taxa de liberação de parasitas em cultura de macrófagos. Os camundongos Gal-1-/- ou Gal-1+/+ tratados com Gal-1 exógena apresentaram as menores taxas de parasitemia. De modo interessante, todos os camundongos Gal-1-/- sobreviveram à infecção, enquanto que os selvagens apresentaram uma drástica redução de sobrevivência após o desafio com T. cruzi. A ausência da Gal-1 endógena ou o tratamento com a Gal-1 exógena provocou no músculo cardíaco de camundongos infectados uma significativa redução infiltrado inflamatório. As dosagens de citocinas séricas indicaram que animais selvagens infectados e tratados com Gal-1 apresentaram uma diminuição de IFN- em relação aos não tratados. Além disso, soros de animais nocautes infectados apresentaram níveis inferiores de diferentes citocinas (TNF-, IFN- , IL-4, IL-10 e IL-12) em comparação com amostras séricas de animais selvagens infectados. As porcentagens de diferentes tipos de células esplênicas (T, B, macrófagos, NKT e NK) foram, geralmente, maiores em camundongos selvagens do que em nocautes após a infecção por T. cruzi. Curiosamente, na cavidade peritoneal de camundongos Gal-1-/- ocorreu um aumento de neutrófilos e macrófagos após 12h ou 24h da infecção, respectivamente. O pico de produção de NO induzido por T. cruzi em macrófagos Gal-1-/- foi mais precoce e intenso do que o obtido por macrófagos Gal-1+/+. Além disso, os macrófagos Gal-1-/- liberaram menos parasitas in vitro em comparação como os macrófagos Gal-1+/+. Com base nesse conjunto de resultados sugerimos que a ausência de Gal-1 endógena ou o tratamento de animais com Gal-1 exógena promoveram perfis imunológicos (resposta inata e adaptativa) favorecedores da resolução da infecção experimental aguda por T. cruzi. / Galectin-1 (Gal-1) is a -galactoside-binding protein and participates in several biological processes, including modulation of immune response. In the literature, there are several reports about the potential therapeutic use of Gal-1 for autoimmune diseases, inflammatory, degenerative and infectious diseases. However, there are few reports on the involvement of Gal-1 in disease caused by Trypanosoma cruzi. Thus, this work was conducted to study the participation of endogenous and exogenous Gal-1 in acute experimental infection by T. cruzi. Recombinant Gal-1, galectin-1-deficient mice (KO - Gal-1-/-) or wild type (WT - Gal-1+/+) mice and macrophages from these animals were used to perform the in vivo and in vitro assays. The animals were infected with trypomastigotes of T. cruzi (strain Y), intraperitoneally. The biological parameters analyzed were parasitemia and survival; histopathology of heart tissue, measurement of nitric oxide by Griess reaction; leukocyte immunophenotyping by flow cytometry; cytokine detection by ELISA and the release rate of parasites in cultured macrophages. Infected-Gal-1-/- mice or infected-Gal-1+/+ mice treated with Gal-1 showed the lowest levels of parasitemia. Interestingly, all infected-KO mice survived after the infection, whereas the infected-WT mice showed a drastic reduction in survival. The absence of endogenous Gal-1 or the exogenous Gal-1 treatment promoted a drastic reduction on inflammatory cells infiltrate in the cardiac muscle of infected mice. The sera of infected-WT mice treated with Gal-1, but not untreated animals, showed high levels of IFN-. Additionally, sera from infected-KO mice showed lower levels of different cytokines (TNF-, IFN-, IL-4, IL-10 and IL-12) compared with serum samples from infected-WT animals. The number of spleen cells (T, B cells, macrophages, NK and NKT) were generally higher in WT mice than in KO mice after infection with T. cruzi. Interestingly, the peritoneal cavity of infected-KO mice presented an increased numbers of neutrophils and macrophages after 12h or 24h of infection, respectively. The peak of NO production induced by T. cruzi in Gal-1-/- macrophages was earlier and more intense than that obtained by Gal-1+/+ macrophage. Furthermore, Gal-1-/- macrophage released fewer parasites in vitro in comparison to Gal-1+/+ macrophages. Taken together, these results suggest that the absence of endogenous Gal-1 or treatment with exogenous Gal-1 promoted immunological profiles (innate and adaptative responses) that cooperate to the resolution of acute experimental infection by T. cruzi
373

Design de complexos rutênio-nitrosilos contendo ligantes polipiridí­nicos: estudos da relação estrutura-atividade e ensaios biológicos / Design of ruthenium-nitrosyl complexes containing polypyridines: studies of the structure-activity relationship and biological assays

Giovanini, Ana Paula Segantin Gaspari 20 June 2018 (has links)
O comportamento do óxido nítrico (NO) em sistemas biológicos vem sendo explorado desde a descoberta de sua importância em processos regulatórios, fisiológicos e em patologias. Atualmente há o grande interesse no desenvolvimento de compostos que possam liberar o NO de forma controlada em locais específicos nas células. Neste contexto, os complexos rutênio-nitrosilos têm se mostrado bastante promissores, visto que podem liberar NO no interior celular por processos redutimétricos, viabilizando sua utilização como agentes antitumorais e/ou tripanocida. Este estudo se baseia na premissa de que a liberação de NO pode ser direcionada para o interior celular através da modulação dos ligantes de forma a obter complexos biocompatíveis. Assim, o presente trabalho visou o delineamento de complexos rutênio-nitrosilos inéditos contendo ligantes polipiridínicos e/ou derivados de aminoácidos e, condução de experimentos a nível biológico. Os novos complexos rutênio-nitrosilos contendo os ligantes 3-etinilpiridina (3-etpy), derivado triazol de lisina e derivado imínico de triptofano foram sintetizados e purificados com êxito. Os ligantes foram caracterizados por RMN de 1H e 13C RMN, HSQC e 1H-1H COSY, espectrometria de massas e espectroscopia no infravermelho. Os complexos foram caracterizados por espectroscopia na região do UV-visível e FTIR, análise elementar, voltametria cíclica e espectrometria de massas. Os complexos foram testados frente a linhagens celulares B16-F10, MCF-7, MDA-MB231 e comparados com os testes em células de mama sadia MCF-10A. Além disso, os complexos foram aplicados a formas amastigotas de Trypanosoma cruzi. Os resultados de viabilidade celular mostraram que os complexos contendo derivado triazol de lisina ocasionam citotoxicidade às células MCF-7, MB-231 e B16-F10. O complexo cis-[Ru(NO)(bpy)2(3-etpy)](PF6)3.2H2O (onde bpy = 2,2\'-bipiridina) apresentou excelente resultado nos testes in vitro e in vivo frente a cepa Tulahuén LacZ e modelo murino, quando da sua associação ao benzonidazol. Os resultados obtidos sugerem possíveis relações existentes entre estrutura-atividade, abrindo novos caminhos para a pesquisa na busca pelo entendimento deste sistema, assim como o desenvolvimento de uma nova classe de compostos. / The behavior of nitric oxide (NO) in biological systems has been explored since the discovery of its importance in regulatory, physiological, and pathological processes. Currently, there is a great interest in the development of compounds that can release NO at specific sites inside cells in a controlled manner. In this context, the ruthenium-nitrosyl complexes have shown to be very promising, since they can release NO inside cells by reduction processes, turning possible its aplications as antitumor and/or trypanocides agents. This study is based on the premise that the release of NO can be directed to inside cells by modulating the ligands in order to obtain biocompatible complexes. In this way, the present work aimed at the design of new ruthenium-nitrosyl complexes containing polypyridine ligands and/or amino acid derivatives, and tests of biological activity. The new ruthenium-nitrosyl complexes containing 3-ethynylpyridine, triazole lysine derivative, and tryptophan imino derivative were synthesized and purified successfully. Ligands were characterized by 1H and 13C NMR, HSQC, and COSY, mass spectrometry and infrared spectroscopy. The complexes were characterized by spectroscopy in the UV-visible region and FTIR, elemental analysis, cyclic voltammetry, and mass spectrometry. The complexes were tested against cell lines B16-F10, MCF-7, MDA-MB231 and the normal breast cell model MCF-10A. In addition, the complexes were tested against amastigote forms of Trypanosoma cruzi. Cell viability results showed that triazole derivative-lysine complexes cause cytotoxicity to MCF-7, MB-231, and B16-F10 cells. The cis-[Ru(NO)(bpy)2(3-etpy)](PF6)3.2H2O (where bpy = 2,2\'-bipyridine) complex presented excellent results in vitro and in vivo tests against the Tulahuén LacZ strain and the murine model, respectively, when it was associated with benzonidazole. The results suggest possible relationships between structure and activity, opening new prospectives in the search for understanding this system, as well as the development of a new class of compounds.
374

Avaliação de possíveis fatores de risco para a infecção pelo Trypanosoma cruzi em crianças: estudo caso-controle em area rural do estado de Goiás / Evaluation of possible risk factors for Trypanosoma cruzi infection in children: a case-control study in a rural area of the state of Goiás

Andrade, Ana Lucia Sampaio Sgambatti de 12 September 1994 (has links)
Um estudo caso-controle para investigar possíveis fatores de risco associados à infecção pelo Trypanosoma cruzi foi realizado em crianças de zona rural, dos municípios de Posse, Simolândia e Guarani de Goiás, localizados na região nordeste do Estado de Goiás. Os participantes do estudo foram selecionados entre 1.990 crianças de 7 a 12 anos de 60 escolas rurais, mediante triagem sorológica com coleta de sangue em papel de filtro por 3 técnicas: Imunofluorescência Indireta, Hemaglutinação Indireta e ELISA. Cento e quarenta e nove (149) crianças com presença de anticorpos anti-T. cruzi em pelo menos 2 testes realizados em amostras de sangue venoso e uma amostra aleatória de 298 crianças soronegativas para os 3 testes, pareadas por sexo, freqüência de idade e comunidade foram incluídas no estudo, respectivamente como Casos e Controles. As moradias dos casos e controles foram visitadas para obtenção de informações sobre presença de vetores na unidade domiciliar, características do domicílio, da família e do ambiente peridoméstico. Nessa ocasião foram coletadas amostras de sangue dos pais dos participantes do estudo. Casos e controles foram comparados em relação a fatores de risco relativos ao ambiente doméstico, peridoméstico e sorologia dos pais. Um segundo banco de dados foi construído com apenas um participante por moradia, correspondendo a 89 moradias de casos e 278 de controles. O modelo de regressão logística condicional foi empregado para controlar as principais variáveis de confusão. Sensibilidade de variáveis preditoras da casa da criança infectada foi também calculada. Uma associação estatisticamente significante foi encontrada entre criança soropositiva e evidência de vetor, ou seus vestígios, no domicílio. A presença de exúvia foi o maior preditor de criança infectada (OR=3,5; LC95 por cento 2,1-5,8), enquanto a presença de vetor sem detecção de vestígios não esteve associada à criança infectada. A identificação de triatomíneos pelos moradores apresentou OR=7,7 (LC95 por cento 2,3-25,5). A infecção em crianças esteve significativamente associada ao número de pessoas residentes na moradia atual. Uma maior proporção de pessoas soropositivas foi detectada nas casas dos casos quando comparada às casas do grupo controle sugerindo uma possível agregação familiar da soropositividade. Características peridomésticas foram semelhantes entre casos e controles, não havendo diferenças de OR entre os dois grupos. Detectou-se associação significativa entre mãe soropositiva e filho soropositivo (OR=3,6; LC95 por cento 2, 1-6,5), indicando a possibilidade da transmissão congênita ou um potencial efeito prejudicial exercido pela soropositividade de mães de recém-nascidos não infectados congenitamente. Entretanto, a associação entre pai infectado e filho infectado não foi estatisticamente significante (OR=1,6; LC95 por cento 1,0-2,7). O relato de vetores pelos moradores mostrou uma sensibilidade de 97,5 por cento em predizer moradia de criança soropositiva. Os aspectos relativos à aplicação da metodologia caso-controle no estudo da infecção pelo T. cruzi e possíveis medidas de vigilância e controle para a região de estudo são discutidos. / A population-based case-control study was conducted in a rural endemic area under routine vector surveillance with the objective of investigating the role of environmental characteristics, family and household factors regarding the risk of T. cruzi infection in childhood. One thousand nine hundred and ninety schoolchildren, aged 7-12 years, corresponding to 82 per cent of students enrolled in 60 village primary schools in three contiguous rural counties in Northeast Goiás were screened for T. cruzi infection between March and September, 1991. Blood samples collected on filter paper were tested by indirect haemagglutination (IHA), indirect immunofluorescence (IIF) and enzyme immunosorbent assay (ELISA) and further confrrmed by testing venous blood samples. Cases were 149 children out of the 158 (7.9 per cent ) positive children to anti-T. cruzi antibodies by at Ieast two serological tests. For each case, 2 seronegative controls were selected among classmates, matched by age (+I- 1 year) and sex. Socio-economicál and environmental factors possibly associated with the risk of T. cruzi transmission were recorded by interviewing parents of cases and controls. Domestic and peridomestic entomological evaluation was done by using pyrethrum às a flushing out agent. A venous blood sample was taken from parents of cases and controls to.be tested for anti-T. cruzi antibodies by the same three techniques. Cases and matched controls were compared regarding three groups of variables: parents\' serology, housing characteristics and peridomestic environment. To control for common exposures among household members and to avoid cluster of seropositive, further analyses were also performed considering only one case and one control per household (89 households of case and 278 households of controls). Conditional logistic regression models (CLR) were used to control for confounding variables and the sensitivity in identifying a house with a positive child was also estimated. Triatomine infestation or evidence of triatomine colonization in the houses were found to be statistically associated to children seropositivity. The presence of exuviae was the strongest predictor of infected children (OR=3.5; 95 per cent CL 2.1-5.8). Parents who reported triatomine bugs inside or outside the house in the last 5 years had odds ratio of 7.7 (95 per cent CL 2.3-25.5) of having an infected child. There was an increased risk of seroreactivity among children associated to the number of family members. Higher proportion of seropositive individuais was found in the household of cases when compared to the household of controls, suggesting familial aggregation. Cases and controls shared similar environmental and peridomestic characteristics. A strong association was found between mother\'s serology and child anti-T. cruzi antibodies (OR=3.6; 95 per cent CL 2.1-6.5) but no statistical association was found between seropositivity of father and child serology (OR=l.6; 95 per cent CL 1.0-2.7). Similar results were obtained after excluding cases and controls living in the same household. The possibility oftransplacental T. cruzi transmission and its implication for Chagas disease control was considered. Among the variables used as predictors of a house with a seropositive child the report of vector presence by householders showed a 97.5 per cent sensitivity. The capture of triatomine vectors in the dwelling was not correlated to a seropositive house. The methodological issues regarding case-control approach in T. cruzi infection and public health interventions for the study area were discussed.
375

Caracterização de uma ATP-Difosfohidrolase de Trypanosoma cruzi / Characterization of an ATP-diphosphohydrolase Trypanosoma cruzi

Nascimento, Ivan Pereira 09 March 1998 (has links)
ATP-difosfohidrolases, comumente denominadas de apirases, descritas pela primeira vez à cerca de quarenta anos atrás, são enzimas que hidrolisam nucleosídeos di ou trifosfatados por um mecanismo que parece ser sequencial, mas sem a formação de um intermediário energético, e de funções metabólicas ainda desconhecidas. Elas tem sido encontradas nas células dos mais diversos pró- e eucariotos investigados e também em tumores. A vasta abundância dessas enzimas e a sua alta atividade enzimática sugerem que as mesmas estariam envolvidas em importantes funções do metabolismo celular. No presente trabalho, identificamos e caracterizamos a presença de uma nova enzima em Trypanosoma cruzi, o agente causador da doença de Chagas, uma apirase, com características semelliantes à outras apirases já descritas em diversos organismos. Diversos ensaios enzimáticos foram feitos mostrando uma atividade enzimática que não foi anulada pelos inibidores clássicos de ATPases tipo-P, tipo-F ou tipo-V. Esta enzima mostrou depende~n·cla para Mg2+, na~o acontecendo o mesmo para Ca2+. Experimentos usando soros imunes contra apirases de outras fontes, reveleram não apenas reação cruzada, mas também sugeriram que a massa molecular dessa enzima no T cruzi, estaria em tomo de 57,5 kDa. Ensaios citoquímicos (imunoflorescência) com o soro imune anti- NTPase de Toxoxplasma gondii, apresentou fluorescência contra diferentes estágios desse protozoa. No entanto, a localização subcelular dessa enzima no T cruzi não ficou muito clara, tomando-se necessário uma microscopia eletrônica para resolver esse problema. Um dado interessante e particular nesse traballio, foi a presença dessa enzima nos diversos estágios do ciclo de vida do parasita, com atividades enzimáticas diferentes para esses mesmos estágios. / ATP-diphosphohydrolases which are generally called apyrases were described for the first time some forty years ago. These are enzymes which hydrolyze di- and triphosphate nucleosides through a mechanism which seems to be sequential, without forming a high-energy enzyme intermediate. Their metabolic function is yet unknown. ATP-diphosphohydrolases have been found in a number of pro- and eucariotic cells and also in tumor cells. The vast abundance ofthese enzymes and their high enzymatic activity suggest that they are involved in important functions in the cell metabolism. In the present work we have identified and characterized the presence of a new enzyme in Trypanosoma cruzi, the agent of Chagas disease, namely an apyrase with characteristics which are similar to other apyrases already described in different organisms. A number of enzymatic assays showed that the enzyme is not inhibited by the classical inhibitors of P-type, F-type or V-type ATPases. The enzyme exhibited a marked dependence on Mg2+ and not on Ca2+. Experiments using immune sera against apyrases of other sources showed cross- reactivity and suggested that the molecular mass of the enzyme in cruzi is around 57.5 kDa. Immunofluorescence cytochemistry using antiToxoplasma gondii NTPase antibodies showed that fluorescence was present in different stages of the protozoa. However, the exact sub-cellular localization of the enzyme in T cruzi was not clear and electron microscopy will be necessary to answer this question. An interesting result of our work is the identification of the enzyme in different stages of the life cycle of the parasite, with different enzymatic activities among the stages.
376

Expressão de componentes da matriz extracelular induzida por vesículas de Trypanosoma cruz liberadas no meio de cultura / Expression of extracellular matrix components by vesicles of Trypanosoma cruzi shed into the culture medium

Paes, Viviana Barbosa 26 September 2008 (has links)
O Trypanosoma cruzi libera para o meio, vesículas contendo material de sua superfície e aparentemente estas vesículas seriam uma maneira de ativar e preparar a célula hospedeira para a invasão, além de induzir um aumento na expressão de alguns componentes da matriz extracelular. Neste trabalho demonstramos que essas vesículas aumentam a expressão de fibronectina na matriz, sendo este aumento dose-dependente e linear ao longo do tempo. Porém, para laminina não conseguimos observar o mesmo comportamento. Nossos resultados também mostram que os constituintes lipídicos das vesículas podem ser os responsáveis pelo aumento da expressão de fibronectina em cultura de células epiteliais. Os dois grandes grupos de glicoproteínas encontradas na superfície do parasita e nas vesículas, mucinas e Tc85 não parecem estar envolvidos no processo. As culturas celulares tratadas com os lipídeos extraídos das vesículas apresentaram um aumento de fibronectina também dose-dependente, porém, com uma resposta linear ao longo do tempo e uma expressão máxima atingida em tempos menores / Trypanosoma cruzi releases to the environment plasma membrane vesicles. Apparently, these vesicles could be a signal released by the parasite to prepare the host cell for the invasion. This study demonstrated that these vesicles induce a dosisdependent expression of fibronectin, linear over time. The same behavior has not been observed for laminin. Our results also show that lipids from the vesicles are involved in the increase of expression of fibronectin by epithelial cells. The two major surface membrane glycoproteins, Tc85 and mucins, also present in the vesicles do not participate in this phenomenon. Cell cultures that have been treated with lipids extracted from T. cruzi membrane vesicles also provoked a dosis-dependent increase in fibronectin and linear over time
377

Protein discovery in African Trypanosomes: studying differential protein expression throughout the parasite life cycle and identification of candidate biomarkers for diagnosing Trypanosome infections

Eyford, Brett Alexander 22 February 2013 (has links)
Research was undertaken to discover and study trypanosome proteins that may play important roles in host-parasite or vector-parasite interactions. The methods used mass spectrometry based proteomics ideally suited for analysis of low abundance molecules. First, isobaric tags were used to monitor changes in proteins expression throughout the life cycle of Trypanosoma congolense, an economically important livestock pathogen. This was the first large scale survey of protein expression in trypanosomes. In addition to generating protein expression data for approximately 2000 different parasite proteins, 6 previously undescribed T. congolense proteins were discovered. Several of the proteins with interesting expression trends were selected for molecular characterization and monoclonal antibody derivation. Second, immunoenrichment and mass spectrometry were used to identify the cognate antigen recognized by a T. congolense-specific monoclonal antibody. The antigen, a flagellar calcium binding protein, was expressed as a recombinant protein and used to test its utility as a potential serodiagnostic antigen for diagnosis of T. congolense infections. Third, a “deep-mining” protein discovery mass spectrometric method was used to identify trypanosome proteins present in the plasma of late-stage African sleeping sickness patients. A total of 254 trypanosome proteins were unequivocally identified by tandem mass spectrometry. These findings are unprecedented since never before have such a large number of pathogen proteins been discovered in human blood using a non-biased approach (i.e. without using a targeted assay). The proteins discovered provide insights into host-parasite interactions and are strong candidates as targets for new diagnostic assays. / Graduate
378

Morphological and Genetic Comparisons between Babesia bovis and Trypanosoma spp. Found in Cattle and White-tailed Deer

Fisher, Amanda 2012 August 1900 (has links)
Babesia bovis has been an important disease agent in the U.S. cattle industry for over a century. Recently, B. bovis-like parasites have been identified in white-tailed deer (WTD; Odocoileus virginianus) in Texas. If the parasites found in the WTD are B. bovis that are able to infect cattle, the disease could re-emerge. Susceptible adult cattle often die from this disease, which would result in severe production losses, as well as a decrease in carcass weights of disease survivors. The B. bovis-like parasite found in WTD was compared to B. bovis from cattle, by ribosomal DNA sequence analysis. Babesia isolated from WTD were found to have 99% identity to B. bovis from GenBank cattle sequences. No cattle samples in this study were found to be positive for B. bovis. On culture of WTD samples, a Babesia parasite could not be visualized based on common morphological features. Trypanosoma cervi has been studied for decades, but all the previous research identified this parasite solely by morphology. Trypanosoma species obtained from different host species was compared by ribosomal DNA sequence analyses. In this study, the Trypanosoma cultured from WTD had the morphological appearance of T. cervi. On sequence analysis, the cattle sequences aligned together with cattle isolates and the WTD sequences aligned closely with elk (Cervus canadensis) sequences, indicating that wild ungulates (WTD and elk) and cattle most likely have separate trypanosome species. On distribution analysis there was a trend in three South Texas counties, where the county with the highest occurrence of Trypanosoma had the lowest occurrence of Babesia; and vice versa. It is possible that Trypanosoma and Babesia blood parasites compete within the mammalian host, but the chi-squared test did not show a significant association between the two parasites in the different counties. On seasonal analysis, the correlation between positive samples and season could not be statistically confirmed, but it appears that Babesia infected animals are found in lowest numbers during hot, dry seasons. It also appears that there is another vector for Trypanosoma in South Texas besides the ked (Lipoptena mazamae) and tabanid fly (Tabanus spp.).
379

Parasitological and molecular characterisation of isometamidium-sensitive and -resistant Trypanosoma congolense and T. brucei brucei isolates from cattle in East and West Africa

Mebratu, Yohannes Afework January 1900 (has links)
Berlin : Freie Univ., Diss., 2005 / Dateiformat: zip, Dateien im PDF-Format. - Erscheinungsjahr an der Haupttitelstelle: 2005
380

cAMP signaling and regulation by phosphodiesterases in trypanosomes /

Laxman, Sunil. January 2006 (has links)
Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 132-145).

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