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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.
41

Host parasite relationships between deer mice (Peromyscus maniculatus) and their eimerian parasites (protozoa)

Fuller, Claire A. 25 October 1994 (has links)
Graduation date: 1995
42

Effects of cytosine-phosphate-guanosine oligodinucleotides (CpG-ODNs) on oral immunization with protein antigen or replicating parasite

Ameiss, Keith Allen 29 August 2005 (has links)
The purpose of this research was to investigate selected methods of mucosal immunization for commercial chickens. Induction of mucosal immunity in commercial chickens through the use of orally administered subunit vaccines or through immunomodulation of the host??s response to live vaccines may be a viable means to control enteric infections in commercial poultry. In the present investigations we evaluated a means for delivering protein antigen in the drinking water and the use of CpG-ODNs, a recently reported mucosal adjuvant, in order to both improve this response and to modulate the host??s immune response when vaccinated with field strains of Eimeria acervulina and Eimeria tenella. In order to evaluate the efficacy of immunizing commercial poultry with subunit vaccines through the drinking water we chose the model antigen Bovine Serum Albumin (BSA). Chicks were administered BSA via intraperitoneal (I.P.) injection, oral crop gavage, or orally through the addition of BSA to the drinking water. These experiments demonstrated the efficacy of drinking water administration to induce antibodyproduction in the serum, intestine, and bile. When BSA was co-administered with CpGODNs we observed a modest increase in this response dependent upon dose. To evaluate the immunomodulation of the host response to live parasite using CpG-ODNs we used three administration models. The first was a single dose of CpGODNs with a trickle immunization regime of Eimeria acervulina. The second was coadministration of CpG-ODNs with a clinical dose of Eimeria acervulina or tenella. The third was pre-administration of CpG-ODNs 24 hours prior to the clinical dose of either species. These studies demonstrate that the first and third models were effective in reducing lesions and improving performance.
43

Studien zur Interaktion des Rinderkokzids Eimeria bovis mit seiner Wirtszelle /

Hermosilla, Carlos. January 2009 (has links)
Zugl.: Giessen, Universiẗat, Habil-Schr., 2009.
44

Control of gastrointestinal parasites in first- and second-season grazing cattle in Sweden /

Larsson, Anna E.V., January 2006 (has links) (PDF)
Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.
45

Einfluss von Eimeria bovis auf die Apoptosefähigkeit der Wirtszelle in vitro

Lang, Mirjam. January 2008 (has links) (PDF)
Zugl.: Giessen, Universiẗat, Diss., 2008.
46

Einfluss von Eimeria bovis auf die Apoptosefähigkeit der Wirtszelle in vitro /

Lang, Mirjam. January 2008 (has links)
Zugl.: Giessen, Universiẗat, Diss., 2008.
47

Host-pathogen interactions at the intestinal epithelial barrier

Fernandes de Moura Guedes, Joana Patricia January 2018 (has links)
This thesis reports investigations of the interactions between the intestinal epithelial barrier and the intracellular apicomplexan Eimeria spp., both in vivo and in vitro. Initially, conventional in vivo studies using genetically modified animals were used to investigate the contribution of innate lymphoid cells (ILCs) to immune protection of the intestinal barrier. Additionally, to understand complex epithelial host-pathogen interactions a novel in vitro model of small intestine organoids was developed. Data suggest that immunoprotection against Eimeria vermiformis infections is mediated by T cells. Furthermore, there is an indication that ILCs have a detrimental effect in Eimeria vermiformis-infected immunocompromised animals. However, the role for ILCs in the regulation of the immune response remains unclear. The life cycles of Eimeria vermiformis and Eimeria falciformis are highly complex, comprising multiple schizogonies followed by a gametogony. In vitro life cycle completion has not been achieved to date due to the limitations of monolayer cell line models. It is likely that for a successful parasite development the interaction of the different epithelial cell types present in intestinal organoids is required. The development of intestinal organoids by Sato and colleagues gave rise to a breakthrough in cellular studies, providing the tools to study complex interactions between host tissues and invading pathogens in vitro. I showed that small intestine-derived organoids grow exponentially after passage and that each organoid contains distinct specialised epithelial cell types, such as Paneth, Goblet or enteroendocrine cells, suggesting that the organoid model closely resembles the native intestinal epithelium and that Eimeria spp. benefit from the three-dimensional structure and physiological characteristics of the organoid model. Intestinal organoids were infected with E. vermiformis or E. falciformis sporozoites. These completed several rounds of asexual replication but did not proceed to the final gametogony. Despite the need for the development of sensitive techniques applicable to three-dimensional cell culture models, these results indicate that intestine-derived organoids are a promising model to study host-parasite interactions at the intestinal epithelial barrier at the cellular and molecular levels.
48

THE UPTAKE OF PARTICULATE ANTIGEN BY SPECIALIZED EPITHELIUM IN THE BURSA OF FABRICIUS AND THE GENERATION OF HUMORAL IMMUNE RESPONSES

Stevens, Laura Joy 01 May 2017 (has links)
The bursa of Fabricius is a central lymphoid organ essential for B cell development and generation of humoral immune responses in birds. The bursa is connected dorsally to the cloaca and continually “samples” the intestinal fluid phase for the presence of antigen. It is comprised of folds or plicae, which are seeded with individual follicles, where antigen processing and presentation occurs for B cell development as well as generation of antibody responses. The plicae are separated from the bursal lumen by interfollicular epithelium (IFE) and specific regions of follicle-associated epithelium (FAE). The FAE is comprised of M cell-like cells, which are specialized for transcytosis of antigen from the bursal lumen into underlying follicles. The uptake of particulate and soluble antigen in the bursa of Fabricius has been previously demonstrated, but how particle size affects their internalization within bursal FAE and the transport of particulate antigen into deeper follicles has not been explored. It has been shown that nanoparticles (NPs) ≤40 nm are most efficiently internalized by the epithelium of the murine intestine and vaginal tract. Therefore, we examined the uptake of 0.04 - 2 μm fluorescent polystyrene NPs in bursa at 1 hour or 6 hours after bursal administration to determine whether bursal epithelium is similarly constrained. Using immunofluorescence microscopy (IFM) and spectrofluorophotometry we found that NP uptake is inversely correlated with NP size. NPs ≤40 nm are most efficiently internalized by the bursal epithelium and bursal follicles, while NPs ≥500 nm are not effectively taken up by the bursal epithelium within 6 hours of administration. Moreover, once the size-limited capabilities of the bursal epithelium were established, we also found that bursal priming of chickens with 20 nm NPs conjugated to IMP-1, a protective antigen of an important avian pathogen Eimeria maxima, induces IMP-1-specific serum IgG following sub-cutandous boosting. We induced similar IMP-1-specific serum antibody responses in chickens primed bursally and sub-cutaneously boosted as those primed and boosted sub-cutaneously. Whether this route of immunization is able to elicit long-term protection must be investigated. A number of infectious diseases, including Infectious Bursal Disease Virus (IBDV), which directly targets the bursa of young birds and prevents the development of the immune system and causes mortality, are prevalent in the poultry industry. While vaccines exist for many of these diseases they confer only partial or incomplete protection; therefore, alternative vaccine strategies must be investigated. In addition, the bursa is an ideal in vivo model for the investigation of endocytic mechanisms for uptake of particulate antigen. Therefore, further characterizing the mechanisms of NP uptake at mucosal surfaces and their immunogenicity will be important for the development of NP-based mucosal vaccines for agriculturally relevant species such as poultry.
49

Avaliação fisiopatológica de coelhos (Oryctolagus cuniculus) infectados experimentalmente com oocistos esporulados de Eimeria stiedae (APICOMPLEXA: EIMERIIDAE)

Freitas, Fagner Luiz da Costa [UNESP] 02 February 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:33:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-02Bitstream added on 2014-06-13T21:06:05Z : No. of bitstreams: 1 freitas_flc_dr_jabo.pdf: 1139081 bytes, checksum: 856bf3c96a6f7eed40da1a35b470f7ae (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A infecção experimental por Eimeria stiedae em coelhos foi realizada com o objetivo de avaliar os sinais clínicos, alterações hematológicas, metabólicas e anatomopatológicas. Foram utilizados 50 coelhos, raça Nova Zelândia, brancos, com idade entre 40 - 60 dias e de pesos semelhantes. Os animais foram randomizados com relação ao peso e distribuídos em 2 grupos experimentais: grupo infectado, inoculado com 1ml de solução contendo 1x104 oocistos esporulados de E. stiedae; grupo controle, inoculado 1 ml de água destilada. Os animais foram avaliados semanalmente, durante 28 dias, a partir da data de inoculação. Os dados foram avaliados utilizando-se método estatístico não paramétrico pelo teste de Wilcoxon ao nível de 5% de significância. Coelhos infectados com oocistos esporulados de Eimeria stiedae tiveram cirrose hepática que afetou o funcionamento normal do referido órgão repercutindo em produção de proteínas de fase aguda e ocasionando consideráveis alterações metabólicas. / The experimental infection by Eimeria stiedae in rabbits was performed to evaluate the clinical signs, hematological, metabolic and pathological changes. Fifty rabbits were used, New Zealand race, white, aged 40 to 60 days and of similar weight. The animals were randomized to the weight and distributed into 2 experimental groups: infected group, inoculated with 1 ml of solution containing 1x104 sporulated oocysts of Eimeria stiedae; control group, inoculated 1 ml of distilled water. The animals were evaluated weekly, for 28 days from the date of inoculation. A statistical was used non-parametric Wilcoxon test method at 5% level of significance. Rabbits infected with sporulated oocysts of Eimeria stiedae had liver cirrhosis that affected the normal functioning of the body resulting in production of acute phase proteins and cause considerable metabolic changes.
50

Ocorrência de parasitoses gastrointestinais em cordeiros no município de Alambari, São Paulo /

Zucatto, Anaíza Simão. January 2013 (has links)
Resumo:O objetivo desta pesquisa foi determinar a ocorrência de parasitoses gastrintestinais e caracterizar molecularmente as espécies de Cryptosporidium spp. em amostras fecais de cordeiros de até um ano de idade do município de Alambari, São Paulo. Um total de 193 amostras foram colhidas e em 126 das mesmas foi efetuada a contagem de ovos por gramas de fezes (OPG) Gordon e Whitlock (1939), para determinar a presença de helmintos e coccídeos do gênero Eimeria. Todas as amostras, foram avaliadas por meio da nested-PCR para amplificação de fragmentos de DNA da subunidade 18S do gene do RNAr para Cryptosporidium. Por meio do teste Qui-Quadrado e/ou Fisher foi verificada a associação da presença das parasitoses gastrintestinais em relação ao sexo, raça e idade dos animais. Das 126 amostras analisadas, 71,4% foram positivas pelo método de OPG, com identificação de 58,9% de ovos de Estrongilídeos; 5,6% de oocistos de Eimeria spp.; coinfecções em, 14,4% de Estrongilídeos e Moniezia spp.; e 15,5% Estrongilídeos e Eimeria spp., e 5,6% infecção pelos três parasitos. Coproculturas foram positivas em 16 amostras, com observação dos gêneros: 31,3% Haemonchus spp.; 12,5% Trichostrongylus spp.; Oesophagsotumum spp. em apenas uma; e infecção mista em 50% por Haemonchus e Trichostrongylus. Para Eimeria spp., a ocorrência foi de 19% dos animais, identificando as espécies: E. crandallis; E. faurei; E. marsica; E. ovinoidalis; E. pallida; E. parva e E. weybridgensis. A nPCR revelou positividade de 15% e o sequenciamento foi possível em 19 amostras, com detecção das espécies: C. xiaoi em 15 amostras, C. ubiquituim em três, e C. meleagridis em uma amostra, sendo estas duas últimas consideradas espécies zoonóticas / Abstract:The objective of this research was to determine the occurrence of gastrointestinal parasites and molecularly characterize the species of Cryptosporidium spp. in stool samples from lambs under one year old in the city of Alambari, São Paulo. A total of 193 samples were collected in 126 and the same was done counting eggs per gram of feces (EPG) Gordon and Whitlock (1939), to determine the presence of helminths and coccidia of the genus Eimeria. All samples were evaluated by nested-PCR amplification of DNA fragments subunit 18S rRNA gene for Cryptosporidium. By using the Chi- square and/or Fisher was significant association of the presence of intestinal parasites in relation to gender, race and age of the animals. Of the 126 samples analyzed, 71.4% were positive by OPG, identifying 58.9% of eggs of Strongyles, 5.6% of oocysts of Eimeria spp.; Coinfection in 14.4% of Strongyles and Moniezia spp., and 15.5% Strongyles and Eimeria spp., and 5.6% infection by the three parasites. Stool cultures were positive in 16 samples, with observation of genres: 31.3% Haemonchus spp., 12.5% Trichostrongylus spp.; Oesophagsotumum spp. in one, and 50% mixed infection with Haemonchus and Trichostrongylus. To Eimeria spp., the incidence was 19% of the animals, identifying the species: E. crandallis; E. faurei; E. marsica; E. ovinoidalis; E. pallida; E. parva and E. weybridgensis. The nPCR was positive in 15% and sequencing was performed in 19 samples with detection of species: C. xiaoi in 15 samples, C. ubiquituim three, and C. meleagridis in a sample, the latter being considered zoonotic species / Orientador:Katia denise Saraiva Bresciani / Banca:Jancarlo Ferreira Gomes / Banca:Suely Regina Mogami Bomfim / Mestre

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