Rozprawy doktorskie: „Giardia”

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Marteau, Catherine. ""Giardia intestinalis" : modéles animaux, leurs caractéristiques et leurs apports à la connaissance de la giardiose humaine". Paris 5, 1991. http://www.theses.fr/1991PA05P130.

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Jaegle, Christophe. "Giardia lamblia : risque hydrique". Strasbourg 1, 1988. http://www.theses.fr/1988STR15084.

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Crouch, Alan Arthur. "Immunodiagnosis of Giardia Lamblia". Thesis, Queensland University of Technology, 1988. https://eprints.qut.edu.au/36772/1/36772_Crouch_1988.pdf.

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Giardia lamblia is the most frequently reported protozoan parasite of the human intestine, causing significan morbidity worldwide. The method currently used in diagnostic medical laboratories for the detection of Giardia lamblia is the microscopic examination of stool specimen or duodenal fluid for the presence of cysts or trophozoites. This technique has been reported as insenstive, with less than 50% of infections diagnosed by the exmaination of one stool specimen.

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Weiland, Malin. "Immunodominant proteins in Giardia lamblia /". Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-158-X/.

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Taweenan, Weerapol. "Molecular epidemiology of Giardia duodenalis". Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539914.

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Giardia duodenalis is a parasitic protozoan that affects the gastrointestinal tract, causing abdominal disorders of various animals and humans. To date, G. duodenalis has been genotypically divided into seven groups (assemblages), namely A to G, found in different host ranges. Whilst assemblages C to G are specific genotypes affecting restricted animal hosts, assemblages A and B parasitise both humans and a number of animal species, and have been considered as having zoonotic potential. The main objective of the current study was to investigate the molecular epidemiology of G. duodenalis in animals and humans in the UK. The current study also evaluated multilocus genotyping and determined the protein changes between assemblages A and B.

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Coradi, Silvana Torossian [UNESP]. "Epidemiologia das parasitoses intestinais e caracterização genotípica de isolados de Giardia duodenalis de escolares do município de Pratânia, estado de São Paulo". Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/101483.

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Made available in DSpace on 2014-06-11T19:31:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T20:22:14Z : No. of bitstreams: 1 coradi_st_dr_botfm.pdf: 625344 bytes, checksum: 6449eeacb0db26adc19ebeca9818d24f (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Universidade Estadual Paulista (UNESP)
O presente estudo foi realizado para investigar a epidemiologia de parasitas intestinais em uma população de escolares do município de Pratânia, Estado de São Paulo, e caracterizar geneticamente os isolados de Giardia duodenalis obtidos dos indivíduos desse grupo. Amostras de fezes de 431 escolares da rede municipal com idade de três a 10 anos e formalmente autorizados a participar do estudo foram colhidas e processadas pelo método de centrífugo-flutuação e pelo kit TF-test®. Além do exame coproparasitológico, as crianças foram submetidas a avaliações clínica e antropométrica e aos pais e/ou responsáveis foi aplicado um questionário para a obtenção de dados epidemiológicos. As crianças parasitadas foram encaminhadas para tratamento de acordo com a prescrição médica e, após 15 a 21 dias do tratamento, novas amostras de fezes foram analisadas para o controle de cura. Para a caracterização genotípica, o DNA extraído de 131 (39 extraídas de amostras positivas e 92 de amostras negativas para Giardia) foi amplificado utilizando técnicas baseadas em PCR para a amplificação das seqüências correspondentes aos genes gdh (glutamato desidrogenase) e tpi (triose-fosfato-isomerase) e os fragmentos amplificados foram seqüenciados. Os seguintes enteroparasitas detectados e suas respectivas freqüências foram: Entamoeba coli (14,2%), Cryptosporidium (11,2%), Giardia duodenalis (9,3%), Endolimax nana (3,3%), Blastocystis hominis (1,62%), Enterobius vermicularis (2,3%), Trichuris trichiura (1,62%), Ascaris lumbricoides (0,7%), e Hymenolepis nana (0,2%). Nas crianças com enteroparasitas, crianças portadoras de infecções por Cryptosporidium, por helmintos e por protozoários comensais, as frequências de infecções foram significativamente mais elevadas quando nas famílias os responsáveis não eram alfabetizados ou se o tempo de escolaridade...
This study was conducted to investigate the epidemiology of intestinal parasites in a population of school children of Pratânia, Estado de Sao Paulo, and genetically characterize isolates of Giardia duodenalis obtained from individuals in this group. Stool samples from 431 schoolchildren aged three to 10 years and formally authorized to participate in the study were collected and processed by means of flotation and the TF-test kit ®. In addition to fecal examination, the children underwent clinical and anthropometric evaluation and parents or guardians received a questionnaire to get additional data. Children positive for intestinal parasites were referred for treatment in accordance with the prescriptions and, after 15 to 21 days of treatment, new samples were analyzed for the control of cure. To genetic characterization, DNA extracted from 131 (39 extracted from positive samples and 92 samples negative for Giardia) was amplified using techniques based on PCR amplification of sequences corresponding to genes gdh (glutamate dehydrogenase) and tpi (triosephosphate isomerase) and amplified fragments were sequenced. The intestinal parasites were detected following frequencies: Entamoeba coli (14.2%), Cryptosporidium (11.2%), Giardia duodenalis (9.3%), Endolimax nana (3.3%), Blastocystis hominis (1, 62%), Enterobius vermicularis (2.3%), Trichuris trichiura (1.62%), Ascaris lumbricoides (0.7%), and Hymenolepis nana (0.2%). In children with intestinal parasites, children with Cryptosporidium infection, helminth and protozoan, the frequencies of infections were significantly higher in families where those responsible were illiterate or if the level of education was no more than five years (P < 0.05). With regard to anthropometric measurements, most children presented to the height / age index, weight / age and weight / height values of z-scores within the normal range... (Complete abstract click electronic access below)

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Coradi, Silvana Torossian. "Epidemiologia das parasitoses intestinais e caracterização genotípica de isolados de Giardia duodenalis de escolares do município de Pratânia, estado de São Paulo /". Botucatu, 2010. http://hdl.handle.net/11449/101483.

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Orientador: Semíramis Guimarães Ferraz Viana
Banca: Ana Julia Urias
Banca: Regina Maura Bueno Franco
Banca: Paulo Câmara Marques Pereira
Banca: Paulo Eduardo Martins Ribolla
Resumo: O presente estudo foi realizado para investigar a epidemiologia de parasitas intestinais em uma população de escolares do município de Pratânia, Estado de São Paulo, e caracterizar geneticamente os isolados de Giardia duodenalis obtidos dos indivíduos desse grupo. Amostras de fezes de 431 escolares da rede municipal com idade de três a 10 anos e formalmente autorizados a participar do estudo foram colhidas e processadas pelo método de centrífugo-flutuação e pelo kit TF-test®. Além do exame coproparasitológico, as crianças foram submetidas a avaliações clínica e antropométrica e aos pais e/ou responsáveis foi aplicado um questionário para a obtenção de dados epidemiológicos. As crianças parasitadas foram encaminhadas para tratamento de acordo com a prescrição médica e, após 15 a 21 dias do tratamento, novas amostras de fezes foram analisadas para o controle de cura. Para a caracterização genotípica, o DNA extraído de 131 (39 extraídas de amostras positivas e 92 de amostras negativas para Giardia) foi amplificado utilizando técnicas baseadas em PCR para a amplificação das seqüências correspondentes aos genes gdh (glutamato desidrogenase) e tpi (triose-fosfato-isomerase) e os fragmentos amplificados foram seqüenciados. Os seguintes enteroparasitas detectados e suas respectivas freqüências foram: Entamoeba coli (14,2%), Cryptosporidium (11,2%), Giardia duodenalis (9,3%), Endolimax nana (3,3%), Blastocystis hominis (1,62%), Enterobius vermicularis (2,3%), Trichuris trichiura (1,62%), Ascaris lumbricoides (0,7%), e Hymenolepis nana (0,2%). Nas crianças com enteroparasitas, crianças portadoras de infecções por Cryptosporidium, por helmintos e por protozoários comensais, as frequências de infecções foram significativamente mais elevadas quando nas famílias os responsáveis não eram alfabetizados ou se o tempo de escolaridade... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: This study was conducted to investigate the epidemiology of intestinal parasites in a population of school children of Pratânia, Estado de Sao Paulo, and genetically characterize isolates of Giardia duodenalis obtained from individuals in this group. Stool samples from 431 schoolchildren aged three to 10 years and formally authorized to participate in the study were collected and processed by means of flotation and the TF-test kit ®. In addition to fecal examination, the children underwent clinical and anthropometric evaluation and parents or guardians received a questionnaire to get additional data. Children positive for intestinal parasites were referred for treatment in accordance with the prescriptions and, after 15 to 21 days of treatment, new samples were analyzed for the control of cure. To genetic characterization, DNA extracted from 131 (39 extracted from positive samples and 92 samples negative for Giardia) was amplified using techniques based on PCR amplification of sequences corresponding to genes gdh (glutamate dehydrogenase) and tpi (triosephosphate isomerase) and amplified fragments were sequenced. The intestinal parasites were detected following frequencies: Entamoeba coli (14.2%), Cryptosporidium (11.2%), Giardia duodenalis (9.3%), Endolimax nana (3.3%), Blastocystis hominis (1, 62%), Enterobius vermicularis (2.3%), Trichuris trichiura (1.62%), Ascaris lumbricoides (0.7%), and Hymenolepis nana (0.2%). In children with intestinal parasites, children with Cryptosporidium infection, helminth and protozoan, the frequencies of infections were significantly higher in families where those responsible were illiterate or if the level of education was no more than five years (P < 0.05). With regard to anthropometric measurements, most children presented to the height / age index, weight / age and weight / height values of z-scores within the normal range... (Complete abstract click electronic access below)
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Chochillon, Christian. ""Giardia intestinalis" : dékystement et culture "in vitro", implantation chez le souriceau". Paris 5, 1988. http://www.theses.fr/1988PA05P503.

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Ringqvist, Emma. "Host-Pathogen Responses during Giardia infections". Doctoral thesis, Uppsala universitet, Mikrobiologi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-108980.

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Giardia lamblia is a eukaryotic parasite of the upper small intestine of humans and animals. The infecting trophozoite cells do not invade the epithelium lining of the intestine, but attach to the brush border surface in the intestinal lumen. The giardiasis disease in humans is highly variable. Prior to this study, the molecular mechanisms involved in establishment of infection or cause of disease were largely uncharacterized. In this thesis, the molecular relationship between Giardia and the human host is described. The interaction of the parasite with human epithelial cells was investigated in vitro. Changes in the transcriptome and proteome of the parasite and the host cells, and changes in the micro-environment of the infection have been identified using microarray technology, and 1- and 2-Dimensional SDS-PAGE protein mapping together with mass spectrometry identification. The first large-scale description of cellular activities within host epithelial cells during Giardia infection is included in this thesis (Paper I). We identified a unique activation of the host immune response and induction of apoptosis upon infection by Giardia. Four important virulence factors of the parasite, directly linked to the success of Giardia infection, were characterized and are presented in Papers II and III. The parasite was shown to have immune-modulating capacities, and to release proteins during host-interaction that facilitate the establishment of infection. Additional putative virulence factors were found among Giardia genes transcriptionally up-regulated during early infection (Paper IV). In summary, this thesis provides important insights into the molecular mechanisms of the host-parasite interaction.

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Winkworth, Cynthia Lee, i n/a. "Land use and Giardia in Otago". University of Otago. Department of Zoology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081219.162139.

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Agriculture is key to New Zealand�s economy with land-use conversions in response to market forces occurring regularly. Recently, high-intensity dairy farming has replaced low-density livestock farming, often degrading surrounding waterways. Of particular concern is that dairy cattle can be a source of the parasite Giardia, which in humans is a common cause of gastrointestinal infection. Thus, this thesis evaluated whether dairy farm conversions posed significant consequences for public health. First I examined the prevalence of Giardia in calves in a rapidly intensifying dairying region of New Zealand. A total of 1190 faecal samples were collected from calves one to seven weeks old during two spring calving seasons and screened by direct immunofluorescent microscopy. Giardia cysts were detected in 31% of samples. To evaluate the potential risk that this environmental source of Giardia posed to the human population, molecular genotyping was used to compare forty Giardia strains isolated from calves with thirty isolates from humans collected in the same region and period. Sequencing the β-giardin gene, Giardia duodenalis assemblages A and B were identified from both hosts, with genotype comparisons revealing substantial overlap of identical genotypes for both assemblages, implying zoonotic transmission. Environmental agencies routinely promote the planting of streamside edges to decrease nonpoint pollution from dairy farms entering waterways. However, current methods for tracking pathogens across farmland and into waterways via surface runoff are limited and typically have been developed using artificially created landscapes. Furthermore, no studies have investigated how Giardia moves across the landscape in farm surface runoff. I developed a field-based tracking method specific for Giardia and used this technique to compare the ability of recently planted vegetation strips with bare soil strips cleared of vegetation at decreasing pathogen concentrations; a typical scenario when planting barriers to reduce waterway contamination. A spike containing a bromide tracer and inactivated Giardia cysts was applied in drip-irrigated surface runoff, with one-minute samples collected from the bottom of the plot. A significant treatment effect was identified for Giardia, with 26% fewer detected in runoff from the planted strip, highlighting the immediate benefit of vegetation planting in removing pathogens. Next I evaluated the effects of four riparian treatments on Giardia runoff: exotic pasture grass and weeds growing in the absence of cattle grazing due to fencing, in comparison to monocultural plantings of three New Zealand native grassland species. Runoff experiments were performed after planting, both prior to and following the main summer growing season. Bromide recovery was high from all four treatments (54 - 99%), with no significant treatment effects. By comparison, Giardia recovery was low (1 - 13%). Prior to summer, two native species reduced Giardia in runoff more than the pasture grass/weed treatment which was almost vegetation-free at this time. After summer, Giardia recoveries were uniformly lower in all treatments. These results demonstrate that after one growing season, fencing waterways produces riparian buffers, via the growth of exotic pasture plants released from grazing, that decrease pathogen concentrations in surface runoff to concentrations indistinguishable from native plantings. Given infectious organisms are known to be in the environment, it is important to assess the risk these pose to human populations. Findings from this research can be used to improve currently available risk-assessment models for Giardia transmission from infected dairy animals via water to humans.

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Palm, Daniel. "Adaptive responses during Giardia-host interactions /". Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-207-1/.

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Bertrand, Sylvie. "Macrophage functions in Giardia lamblia infections". Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61867.

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Cevalloas, Gaos Ana Maria. "Biological differences between Giardia lamblia isolates". Thesis, Queen Mary, University of London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309122.

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Hough, Victoria Charlotte. "Characterisation of metronidazole resistant Giardia intestinalis". Thesis, University of Hull, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272033.

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Saleh, Meriam Naim. "Detecting Giardia: Clinical and Molecular Identification". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/89367.

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The protozoan parasite Giardia duodenalis (syn. G. lamblia, G. intestinalis) can cause diarrhea in humans, cats, dogs and other animals. Giardia duodenalis consists of eight assemblages (A-H) that are morphologically identical but genetically distinct. Assemblages C-H are generally species-specific, while A and B infect people and animals and are considered potentially zoonotic. Most canine and feline isolates belong to their respective species-specific assemblages, but isolates of assemblages A and B (predominantly found in humans) have also been recovered from dogs and cats. Diagnosis of infection has historically been by morphologic techniques (observing trophozoites on direct fecal smears or cysts on centrifugal zinc sulfate fecal flotations), and it is currently recommended to use morphologic techniques in conjunction with a sensitive and specific antigen test. Diagnosis is important for management of clinical giardiasis in cats and dogs and also to identify the assemblage present to determine its zoonotic potential. In my dissertation research I evaluated diagnostic techniques in use for companion animals, including centrifugal zinc sulfate fecal flotation, antigen tests optimized for use in dogs and cats, direct immunofluorescent assay (IFA), and Polymerase Chain Reaction (PCR). I showed that when compared to the reference IFA the veterinary optimized antigen tests performed similarly and had no statistically significant differences in sensitivity or specificity when combined with a centrifugal zinc sulfate fecal flotation test. Sensitivity and specificity by comparison to IFA was ≥ 82% and ≥ 90%, respectively, for all diagnostic tests evaluated in dogs and cats. When analyzed via Bayesian analysis sensitivity and specificity for all diagnostic tests was ≥83% and ≥95%, respectively. The Bayesian analysis also showed that using the direct immunofluorescent assay (IFA) as the reference test was supported. I also evaluated PCR as a molecular diagnostic technique to detect Giardia infections in dogs with soft stool or diarrhea (mimicking clinical signs of infection). I utilized both conventional and real time PCR assays and compared the results to the recommended method of diagnosis, the zinc sulfate fecal flotation combined with an immunoassay test. I found that agreement between PCR and microscopy combined with an immunoassay was poor to fair and varied depending on the molecular parameters and size of the DNA target underscoring the complexity of test evaluation and molecular diagnostics for Giardia. I also evaluated cats from a varied population (owned, shelter, feral) in Virginia to determine to what extent (if any) they were infected with potentially zoonotic assemblages of Giardia. The species-specific assemblage F was detected in 57% of the samples and assemblage A, which is considered potentially zoonotic, was recovered from 32% of the sampleI. In 11% both assemblages F and A were detected. We showed for the first time that cats in Virginia are infected with potentially zoonotic assemblages of Giardia.
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Bertrand, Isabelle. "Détection et génotypage des kystes de Giardia lamblia à partir de matrices environnementales et d'échantillons biologiques". Nancy 1, 2005. http://docnum.univ-lorraine.fr/public/SCD_T_2005_0210_BERTRAND.pdf.

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Dans les pays industrialisés, les nombreuses épidémies d'origine hydrique dues aux protozoairesont souligné l'importance de ces micro-organismes longtemps sous-estimés par rapport aux bactéries et aux virus. Parmi ces protozoaires, Giardia lamblia est une espèce complexe composée de sept génotypesdont seulement deux sont considérés comme pathogènes pour l'Homme, mais aussi pour de nombreux mammifères. Les méthodes de référence actuelles font appel à l'immunofluorescence qui autorise uniquement la détection de l'ensemble des kystes du genre Giardia. Dans ce contexte, notre étude a pour objectif de développer des outils permettant une détection spécifique des espèces et des génotypes, puis de les transférer à l'analyse d'échantillons environnementaux et biologiques. La première partie de notre étude est réalisée uniquement à partir de kystes en suspensions purifiées. Dans un premier temps, nous avons sélectionné et validé un système de détection par PCR en temps réel permettant d'augmenter la spécificité de détection pour l'espèce Giardia lamblia par rapport à l'immunofluorescence. Au-delà de la mise en évidence de cette espèce, nous avons également mis en place deux PCR en temps réel assurant la détection spécifique des génotypes A et B pathogènes pour l'Homme, ainsi que deux PCR analytiques destinées à la mise en évidence des génotypes C et E spécifiques respectivement d'animaux domestiques et d'élevage. La sensibilité, la spécificité et la rapidité de détection constituent les avantages majeurs de ces différents outils. La deuxième partie de nos travaux vise à transférer ces techniques de détection à l'analyse d'échantillons environnementaux suite à l'évaluation de protocoles de concentration et de purification des kystes. Les techniques basées sur la détection du génome sont en effet sensibles à de nombreux composés inhibiteurs présents à des concentrations élevées dans les échantillons biologiques et surtout environnementaux, et pouvant alors entraîner une sous-estimation de la contamination par ces micro-organismes. Différentes techniques de purification basées sur la densité des éléments à purifier (flottation et gradients de densité), la séparation immunomagnétique (IMS), mais aussi des procédés destinés à limiter l'effet des inhibiteurs de PCR lors de l'extraction des acides nucléiques ou de leur amplification sont évalués au cours de cette étape. Le protocole sélectionné suite à ces expérimentations comporte une concentration par centrifugation suivie par une purification des kystes par séparation diphasique à l'acétate d'éthyle et une flottation sur solution de PercollTM-saccharose (d : 1,10). L'étape d'extraction des acides nucléiques est également modifiée au niveau de la digestion de protéines et de la purification des acides nucléiques. La troisième partie constitue l'étape majeure de notre étude puisqu'elle concerne tout d'abord la détection de l'espèce Giardia lambha suivie par une analyse plus fine au niveau des génotypes. La détection de l'espèce G. Lamblia s'avère alors positive pour l'ensemble des prélèvements. Des disparités sont ensuite mises en évidence pour les génotypes. Le génotype A est ainsi isolé au niveau des stations d'épuration et de l'abattoir, alors que le génotype B, plus rarement mis en évidence, n'est détecté dans aucun échantillon provenant de l'abattoir. La détection du génotype E confirme la différence observée entre ces sites puisqu'il est détecté uniquement dans les eaux usées de l'abattoir et apparaît comme un marqueur potentiel de contamination non-humaine. Les systèmes spécifiques des génotypes A et B ont également permis de génotyper des kystes de Giardia lamblia isolés de selles humaines. Le génotype B apparaît alors comme nettement majoritaire pour l'ensemble des prélèvements quelque soit leur origine. Cette première étude réalisée en France permet de détecter les génotypes B et A dans 64 % et 36 % des cas sporadiques respectivement. L'analyse de cas regroupés aboutit également à la mise en évidence du génotype B. Ces expérimentations démontrent l'intérêt des techniques de biologie moléculaire pour une détection rapide, sensible et spécifique, mais aussi pour le génotypage de ce protozoaire au niveau environnemental et biologique.

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Bertrand, Isabelle Schwartzbrod Janine. "Détection et génotypage des kystes de Giardia lamblia à partir de matrices environnementales et d'échantillons biologiques". [s.l.] ([s.n.]), 2005. http://www.scd.uhp-nancy.fr/docnum/SCD_T_2005_0210_BERTRAND.pdf.

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Carvalho, Thaís Batista de. "Identificação e caracterização dos produtos de excreção/secreção de trofozóitos de Giardia duodenalis /". Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/89970.

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Orientador: Semiramis Guimarães Ferraz Viana
Banca: Teresa Cristina Goulart de Oliveira Sequeira
Banca: Regina Maura Bueno Franco
Resumo: O presente estudo foi desenvolvido com o objetivo de identificar e caracterizar os produtos de excreção/ secreção (PE/S) de trofozoítos de Giardia duodenalis de uma cepa axênica isolada no Brasil (BTU-11), tendo por referência a cepa padrão Portland 1 (P-1) isolada nos Estados Unidos. Os PE/S foram obtidos a partir dos sobrenadantes de cultura de trofozoítos mantidos em meio RPMI por 6 horas a 37oC. Os PE/S de cada cepa foram analisados quanto ao perfil eletroforético em géis de poliacrilamida (SDSPAGE) e a atividade proteolítica foi avaliada em géis contendo gelatina e colágeno tipo I a 0,2% e em ensaios empregando hemoglobina a 0,1%. A caracterização das proteases dos PE/S foi realizada em ensaios para avaliar o efeito de inibidores sintéticos de cisteína, serina, metalo e aspartil proteases sobre a degradação de cada substrato testado. A análise dos perfis protéicos revelou padrões simples, porém distintos quanto ao número de bandas de proteínas, visualizando nos PE/S das cepas P-1 e BTU-11, respectivamente, seis e quatro bandas com massas moleculares distribuídas na faixa de 123 a 28 kDa. Quanto à atividade proteolítica, todos os substratos foram degradados por enzimas presentes nos PE/S. A atividade gelatinolítica foi observada na faixa de 77 a 18 kDa, destacando-se seis bandas evidentes de aproximadamente 77, 66, 54, 52, 21 e 18 kDa. A degradação do colágeno foi detectada na faixa de 145 a 18 kDa, sendo que as zonas de proteólise de maior evidência foram observada nas faixas de 145 a 82 kDa e de 56 a 34 kDa, onde destacam-se as bandas de 145, 96, 82 e 34 kDa. A análise dos padrões de hidrólise da hemoglobina demonstrou similaridade entre as cepas e revelou degradação total da cadeia dimérica e lise parcial da cadeia monomérica. A atividade gelatinolítica e... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The present investigation was undertaken to examine the protease activity in excretory/secretory (E/S) products of Giardia duodenalis trophozoites of an axenic Brazilian strain (BTU-11) and the reference strain Portland 1 (P1). E/S products in conditioned medium by trophozoites of each strain were tested in SDS-polyacrylamide gel electrophoresis for the protein profiles, and the proteases activity was analyzed using substrate gelatin and collagen impregnated SDS-PAGE and haemoglobin assay. The proteases characterization was based on inhibition assays including synthetic inhibitors for cysteine, serine, metallo and aspartic proteases. Electrophoresis analysis of E/S products revealed a banding pattern composed by few bands (4-6 bands) in the migration region of 123 to 28 kDa. Proteolytic products were detected in the conditioned medium by trophozoites of both assayed strains. In the gels containing copolymerized gelatin and collagen, E/S products promoted degradation of both substrates and the most evident proteolysis zones were distributed in the migration regions of 77 to 18 kDa and 145 to 18 kDa, respectively, in the patterns of gelatinolytic and collagenolytic activities. Degradation of haemoglobin was also observed, and the pattern of hydrolysis was similar in both E/S products assayed. Inhibiton assays showed that the main proteolytic activity in E/S products is due to cysteine proteases although the presence of serine proteases was also indicated, mainly in the hydrolysis of haemoglobin. These observations are relevants, especially ...(Complete abstract click electronic access below)
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Martins, Juliana. "Caracterização molecular de isolados de Giardia spp. provenientes de amostras fecais de origem humana da Baixada Santista, estado de São Paulo, pela análise de fragmentos do gene codificador da glutamato desidrogenase (gdh) e beta-giardina (bg)". Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-14122011-115047/.

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Giardia duodenalis é um protozoário entérico de distribuição mundial responsável por causar a giardíase em uma grande variedade de mamíferos, incluindo os humanos. É considerada uma espécie complexa, no qual os isolados podem ser classificados em sete agrupamentos genéticos distintos apesar de serem morfologicamente indistinguíveis. O presente trabalho teve como objetivo avaliar a variabilidade genotípica de isolados de G. duodenalis provenientes de humanos naturalmente infectados, residentes em cidades do litoral de São Paulo, na Baixada Santista. A caracterização molecular de 43 isolados pelo seqüenciamento parcial de genes codificadores da enzima glutamato-desidrogenase (gdh) e da proteína beta-giardina (bg) mostrou que o assemblage B da G. duodenalis é o mais freqüente na região litorânea, ocorrendo em 53,5% (n=23) das amostras, sendo o assemblage A identificado em 34,8% (n=15). A maioria das seqüências obtidas pelo gene gdh se mostrou polimórfica, caracterizada por picos duplos de nucleotídeos em algumas posições em cromatograma e quando a análise dos dois genes foi combinada cinco isolados apresentaram identidades diferentes. A esses fenômenos duas explicações são atribuídas, infecção mista ou heterozigose de seqüência alélica. As análises filogenéticas mostraram que o gene bg é mais conservado que o gene gdh, não sendo capaz de discriminar os sub-agrupamentos que constituem os Assemblages do parasita. Com base nos resultados apresentados podemos concluir que a participação de genótipos zoonóticos é relevante na epidemiologia das giardíases nos indivíduos residentes das cidades litorâneas do estado de São Paulo e que estudos de caracterização molecular da G. duodenalis são indispensáveis para melhor conhecimento da epidemiologia desta infecção.
Giardia duodenalis is an enteric protozoa of global distribution responsible for causing giardiasis in a wide range of mammals including humans. Is considered complex specie in which the isolates can be classified in different genetic groups despite to be morphologically indistinguishable. The purpose of this study was evaluating the genetic variability of G. duodenalis isolates from humans naturally infected residents in the coast cities of Sao Paulo, in Baixada Santista. The molecular characterization of 43 isolates using the gene encoding glutamate-desidrogenasi enzyme (gdh) and beta-giardin protein (bg) showed that the assemblage B is the most common in the coast region, occurring in 53.5% (n=23) samples, the assemblage A was identified in 34.8% (n=15). Most sequences obtained by the gdh gene showed polymorphism, characterized for double peaks of nucleotides in some chromatogram positions and when the analysis of two genes was combined five isolates were differently identified. For this phenomena can be attributed two explanations, mixed infections or heterozygosis allelic sequence. The phylogenetic analysis showed that bg gene is more conserved than gdh gene, not being able to discriminate the sub-groups of parasite assemblages. Based on the presented results we can conclude the participation of zoonotic genotypes is important in the epidemiology of giardiasis in residents of the coast cities of Sao Paulo state and molecular characterization studies of G. duodenalis are essential for better understanding the epidemiology of this infection.

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Meireles, Paôla Wolski. "Giardia S.P./Giardíase em animais de companhia". reponame:Repositório Institucional da UFPR, 2011. http://hdl.handle.net/1884/25769.

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Resumo: O objetivo desse trabalho primeiramente foi, comparar as técnicas coproparasitológicas, Sheater (1929) e Faust (1938), nas diferentes populações, felina e canina, provenientes de ambientes com condições sanitárias distintas, analisando concomitantemente dados como sexo e faixa etária. Os isolados positivos, ou seja, aqueles animais que foram observados cistos de Giardia sp. no material fecal, foram isolados, juntamente com os animais negativos as técnicas anteriormente citadas, para serem submetidos à técnica molecular e responder ao outro objetivo do trabalho, ou seja, comparar métodos diagnósticos, coproparasitológicos e moleculares.Tanto na população canina quanto na felina, numericamente a técnica de Faust mostrou-se mais eficiente, porém somente na população felina a diferença foi estatisticamente significativa. A faixa etária mais acometida pelo protozoário nos cães foi a ,de 3 a 6 meses, e nos gatos foi na maior de 6 meses. Quanto ao sexo, os machos da população albergada e as fêmeas da população canina domiciliada obtiveram valores numericamente superiores. Na população felina os machos que mais foram acometidos pela infecção. Ao comparar técnica molecular com coproparasitológica, na população canina não houve diferença estatística, porém numericamente o valor do resultado para técnica coproparasitológica foi superior a molecular. Na população felina observou-se resultado estatístico significativo entre as técnicas moleculares e coproparasitológica., sendo a molecular mais eficiente. O presente trabalho direciona o Médico Veterinário na rotina clínica, tanto na escolha da melhor técnica, diagnóstica, quanto na situação mais apropriada para adoção de medidas profiláticas, tendo em vista a relevância do protozoário pesquisado.

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Gilmour, Robert Angus. "Giardia spp cysts and the aquatic environment". Thesis, University of Strathclyde, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293498.

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Kraft, Martin Rolf. "Giardia duodenalis - epithelial interaction and barrier function". Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21045.

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Die Durchfallerkrankung Giardiasis wird durch den Protisten Giardia duodenalis ausgelöst. Die Infektion erfolgt fäkal-oral, meist über kontaminiertes Trinkwasser. Der Parasit kolonisiert den oberen Bereich des Dünndarms und heftt sich an das Epithel, wodurch es die Krankheitsbeschwerden auslöst. Allerdings sind Details über die Mechanismen der Pathogenese unbekannt. Dazu kommt, dass der Ausgang einer Infektion fallspezifisch starken Schwankungen unterworfen ist, von selbst-limitierend bis chronisch und asymptomatischer Kolonisierung bis hin zur schweren Enteritis. Ein möglicher Pathomechanismus ist der Wegfall der Barrierefunktion des Dünndarmepithels, z.B. durch Beeinträchtigung von tight junctions oder Zelltod. In dieser Arbeit wurden Effekte von G. duodenalis auf in vitro Modellsysteme des humanen Dünndarmepithels untersucht. Dazu wurden hauptsächlich Daten über die Barrierefunktion sowohl von der weit verbreiteten Caco-2 Zelllinie, als auch über ein neu etabliertes humanes Dünndarmorganoidsystem, erhoben. Es konnte gezeigt werden, dass mehrere - mitunter in der Literatur als hochvirulent beschriebene - G. duodenalis Isolate zu keinerlei Beeinträchtigung der Barrierefunktion oder irgendeiner anderen untersuchten potenziellen Schädigung an zwei unterschiedlichen Caco-2 Zelllinien unter diversen Infektions- und Kulturbedingungen führte. Jedoch andererseits das neu entwickelte Dünndarmorganoidsystem mit pseudo-luminalem Medium TYI S 33 reproduzierbar die Zerstörung des Epithelmodells mit Zellverlust, Zelltod (apoptotisch und nicht-apoptotisch), Störung der tight junctions (Abbau und Dislokation von Claudinen und ZO-1) und den Verlust von Mikrovilli innerhalb ein bis zwei Tage nach Parasiteninfektion zeigen konnte. Zudem wurde das Auftauchen von ClCa-1-Signalen unter andauerndem Infektionsstress beobachtet, was die Differenzierung bzw. Metaplasie zu Becherzellen nahelegt, jedoch keine Wirtsreaktion auf die Gewebszerstörung zu sein scheint.
The protozoan parasite Giardia duodenalis is the etiological agent for the intestinal diarrheal disease giardiasis. Infections are acquired via the fecal-oral route, mostly via uptake of cysts from contaminated drinking water. The colonization of the hosts’ duodenum and upper jejunum and the attachment of Giardia trophozoites onto the epithelium is the cause of a variety of gastrointestinal complaints but the exact pathomechanisms are unknown. Furthermore, the outcome of Giardia infections varies greatly between individuals, ranging from self-limiting to chronic, and asymptomatic to severe enteritis. One proposed mechanism for the pathogenesis is the breakdown of intestinal barrier function, e.g. by tight junction impairment or induction of cell death. In this work, effects of G. duodenalis on in vitro models of the human small intestinal epithelium were investigated by studying mainly barrier-related properties and changes of widely used Caco-2 cells as well as newly established human small intestinal organoid-derived monolayers (ODMs). It could be shown that several isolates of G. duodenalis, some described as highly virulent, fail to induce barrier dysfunction or any other investigated pathological effect on two Caco-2 cell lines under various infection and culturing conditions. On the other side, by developing a new organoid-based model system and the use of luminal mock medium TYI-S-33, considerable epithelial disruption (including loss of cells), cell death (apoptosis and non-apoptotic), tight junction impairment (degradation and dislocation of claudins and ZO-1), and microvilli depletion reproducibly induced by G. duodenalis trophozoites between one and two days after infection could be observed. Moreover, emergence of ClCa-1 positive cells with ongoing parasite infections suggest epithelial differentiation or metaplasia towards goblet cells, which is furthermore not associated to tissue damage.

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Tsarukyanova, Iryna G. "How is encystment regulated in Giardia intestinalis". Cleveland State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=csu1337102786.

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Hart, Christopher J. "Identifying new compounds active against Giardia duodenalis". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/391055.

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Giardia are a genus of enteric pathogens consisting of at least six species (Monis et al. 2009), of which one, Giardia duodenalis, infects humans (Heyworth 2016). In addition to humans, G. duodenalis parasites infect other mammals, which may act as reservoirs for human infection (Traub et al. 2004; Yaoyu and Xiao 2011; Abeywardena et al. 2015; Sroka et al. 2015; Štrkolcová et al. 2015; Heyworth 2016). In humans Giardia infection can be asymptomatic, however all infected hosts shed cysts and can transmit parasites (Oliveira-Arbex et al. 2016; Figgatt et al. 2017). Giardia infection can cause giardiasis, a diarrhoeal disease with a variety of clinical manifestations (Wolfe 1992; Homan and Mank 2001; Sahagún et al. 2008; Nielsen et al. 2014). An estimated 180 million symptomatic human Giardia infections occur every year (Kirk et al. 2015), and treatment is reliant on a small number of chemotherapeutic classes, all of which are associated with liabilities. Liabilities include but are not limited to; poor treatment efficacies, long treatment courses and side-effects which impact compliance (Cina et al. 1996; Wright et al. 2003; Escobedo and Cimerman 2007; Nabarro et al. 2015). Growing parasite resistance to the first-line treatment drugs, the 5-nitroimidazoles, is also a concern (Nabarro et al. 2015). The aim of the current study was to pave the way towards improved treatment options for giardiasis by identifying new lead compounds for drug development, and to further examine the activity of these compounds. To achieve this, a new anti-Giardia activity assay to assess parasite growth in micro-titre plates under microaerobic (3 % O2) conditions was developed. This image-based assay uses bright-field microscopy paired with digital phase-contrast microscopy and supervised machine learning software, PhenoLOGIC and Harmony® (Perkin-Elmer, USA) to differentiate and enumerate parasites. Growth assessment does not require cell-staining or a genetically modified parasite line, thus it can assess the growth of any established Giardia line, at multiple time-points which are distinct advantages over other assays currently used in the Giardia field. Importantly, this assay gives 50 % inhibitory (IC50) values for control compounds metronidazole (IC50; 2.7 ± 0.7 µM), albendazole (54 ± 5 nM) and furazolidone (200 ± 90 nM) , against BRIS/91/HEPU/1279 at 48 h consistent with those previously reported by others (Edlind et al. 1990; Cedillo-rivera et al. 2002; Hounkong et al. 2011; Tejman-Yarden et al. 2011). The validated image-based assay was used to screen a sub-set of Compound Australia’s Open-access Scaffold Library for anti-Giardia activity. A total of 2451 compounds (two per scaffold) were screened at 10 µM. Forty-one compounds (1.7 % hit rate) were validated as having anti-Giardia activity (>50 % inhibition at 48 h) in these assays. Secondary testing of hit compounds to determine IC50 values against Giardia and neonatal foreskin fibroblasts (NFF) identified five compounds with IC50 values <1 µM and >10 fold selectivity for parasites over mammalian cells. Rational selection based on selective activity, chemical novelty and chemical liabilities identified seven hit series for further investigation. Compounds within these series (196 total; ~28/series) were then assessed to examine structure activity relationships (SARs) and prioritize hit series for development. Analogues of particularly potent and selective series were also synthesized by collaborators and assessed for anti-parasitic activity and selectivity. The most promising hit was three orders of magnitude more potent than the current first-line anti-Giardia treatment drug, metronidazole (SN00798527; series CL9569; 48 h IC50 9 nM vs. metronidazole 48 h IC50 3 µM), with a selectivity index (SI) of >11,000. Importantly, this activity was maintained against multiple Giardia isolates encompassing both human infecting G. duodenalis assemblages (A and B) and against metronidazole resistant parasites. These data suggest that SN00798527 has a different mode of action to metronidazole and that cross-resistance with the 5-nitroimidazoles is unlikely, and that the molecule is likely to be equally effective against both human infecting genotypes. Preliminary in vivo data suggests that this compound is well tolerated in Swiss mice, with no toxicity seen at oral doses of up to 0.7 mg/kg (10x the calculated therapeutic dose (CTD) for this compound). Preliminary data also suggest that SN00798527 is active in a murine giardiasis model. Neonate Swiss mice dosed daily for three days with orally administered SN00798527 (0.7 mg/kg 10xCTD) harboured significantly reduced parasite loads (73 % reduction in trophozoite load and 99 % reduction in cyst load) compared to untreated control mice. Taken together these data highlight the in vivo potential of series CL9596 and suggest further in vivo trials and mode of action studies are warranted. Lead compounds within two additional compound series (SC003542 and CL9406), SN00776497 and SN00797640 also demonstrated promising in vitro activity (48 h IC50 values 183 and 23 nM and SI of 291-343 and 24-90, respectively) that was consistent against multiple isolates encompassing both human infecting G. duodenalis genotypes and against metronidazole resistant parasites. While the timeframe of this project did not permit the in vivo anti-Giardia activity of these molecules to be evaluated, toxicity studies in Swiss mice also demonstrated these compounds to be safe at doses of up to 2 mg/kg and 5 mg/kg respectively (10x CTD).
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Arbex, Ana Paula Oliveira. "Genotipagem dos isolados de Giardia duodenalis em famílias de pescadores da colônia de Porto Said, Botucatu, São Paulo /". Botucatu, 2015. http://hdl.handle.net/11449/132021.

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Orientador: Semiramis Guimarâes Ferraz Viana
Banca: Carlos Magno Castelo Branco Fortaleza
Banca: Jose Ricardo Jensen
Resumo: As enteroparasitoses ainda persistem como problema de saúde pública, sobretudo nos países em desenvolvimento, onde o protozoário Giardia duodenalis (sin. Giardia intestinalis, Giardia lamblia) destaca-se como uma das causas mais frequentes de diarreia em crianças. Assim, no presente estudo investigou-se a prevalência de das infecções causadas por Giardia e outros parasitas intestinais e funcionários da Creche e Escola Municipal de Educlação Infantil (CEMEI) do distrito de Vitoriana, Botucatu-SP, incluindo-se também os familiares e cães das crianças cujos exames de fezes foram positivos para Giardia. Paralelamente, por meio de análise multilocular empregando os genes-alvo beta-giardina (bg), triose fosfato isomerase (tpi) e glutamato desiderogenase (gdh), caracterizou-se geneticamente os isolados de G. duodenalis detectados nessa população. Para isso, foram analisadas três amostras de fezes de 123 crianças (0 a 6 anos), 14 funcionários, 44 familiares e 20 cães. As amostras foram processadas por centrífugo-sedimentação e centrífugo-flutuação e examinadas em microscópio óptico. Parasitas intestinais foram identificados em 50 das 123 amostras de fezes de crianças (41,6%), e parasitismo por Giardia foi detectado em 21,9% das crianças (27/123). Das 27 famílias que tinham crianças parasitadas por Giardia, apenas 16 (44 indivíduos) forneceram amostras de fezes. Nestas, cistos de Giardia não foram detectados em nenhuma das amostras dos funcionários e dos cães examinadas. Com respeito ao parasitismo por Giardia nas crianças que frequentam a creche, as análises revelaram que as crianças mais jovens estão em maior risco de contrair a infecção por Giardia (OR = 0,69; IC95% = 00.49-0.97; p = 0,03). Além disso, verificou-se que o risco de infecção aumenta quanto maior for o número de indivíduos no domicílio (OR = 1,8; IC95% = 1,07-3,07; p = 0,03). Para a caracterização molecular dos isolados de Giardia, o DNA...
Abstract: The intestinal parasites persist as a public health problem, especially in developing countries, where the protozoan Giardia duodenalis (syn. Giardia intestinalis, Giardia lamblia) stands out as one of the most common causes of diarrhea in children. The present study was conducted to investigate the prevalence of Giardia and other intestinal parasites in children and workers of a daycare center of Vitoriana, a district of Botucatu municipality, São Paulo State, including also the household members and dogs of the children tested positive for Giardia. In addition, we proposed to investigate the genetic diversity of G. duodenalis infection in these population using three gene loci beta-giardin (bg), triose phosphate isomerase (tpi) and glutamate dehydrogenase (gdh). For this, three samples were analyzed from 123 children feces (0-6 years), 14 workers, 44 families members and 20 dogs. Samples were processed by centrifugal sedimentation and flotation and examined under a light microscope. Intestinal parasites were identified in 50 of 123 fecal samples from children (41.6%), and Giardia was the most frequent parasite detecte (21.9%). Out of the 27 families of children tested positive for Giardia, only 16 (44 individuals) provided stool samples. In these samples, cysts were detected in two samples. Focusing on Giardia infection among children attending day care, the analysis showed that younger children are at higher risk of acquiring Giardia infection (OR = 0.69; 95% CI = 00.49-0.97; p = 0.03). In addition, children living in families with a higher household density were more likely to be infected (OR = 1.8; 95% IC = 1.07-3.07; p = 0.03). DNA extracted from 186 stool samples (35 negative and 151 positive samples for microscopic examination) were amplified and the products sequenced generating 59 sequences as follow: 15 for bg, 25 for tpi and 19 for gdh. Out of the 29 isolates assessed, the sequencing analysis ...
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Durigan, Mauricio 1985. "Estudos genético-moleculares em Giardia duodenalis = caracterização da diversidade genética e análises populacionais em amostras clínicas e ambientais na região metropolitana de Campinas, São Paulo, Brasil = Genetic and molecular studies in Giardia duodenalis: molecular characterization of genetic diversity and population genetic analysis in clinical and environmental samples in the metropolitan region of Campinas, São Paulo, Brazil". [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316469.

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Orientador: Anete Pereira de Souza.
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-27T05:07:09Z (GMT). No. of bitstreams: 1 Durigan_Mauricio_D.pdf: 7600085 bytes, checksum: 74ae2337a73b6edfb14a403af4ffa590 (MD5) Previous issue date: 2015
Resumo: Giardia duodenalis é um protozoário flagelado que parasita o homem e diversos animais domésticos e selvagens. Este parasito causa a doença giardiose que é uma das mais prevalentes doenças parasitárias de veiculação hídrica do mundo, responsável por aproximadamente 280 milhões de casos anualmente. Existe uma considerável variabilidade genética em G. duodenalis, de modo que seus isolados foram divididos em oito grupos genéticos (A-H), dois dos quais (A e B) são encontrados tanto em humanos quanto em animais. Os demais grupos (C-H) parasitam outros animais e apresentam maior especificidade a determinados hospedeiros não humanos. A contaminação ambiental por Giardia tem sido amplamente descrita embora esses estudos, em sua maioria, são realizados no nível de identificação de espécie. Há falta de estudos que correlacionam a contaminação ambiental e infecções clínicas na mesma região. O presente trabalho teve como objetivo principal contribuir para o conhecimento da diversidade genética da espécie Giardia duodenalis. Primeiramente, foi realizada a genotipagem multilocos dos principais grupos genéticos de G. duodenalis na região metropolitana de Campinas. Foram encontrados grupos genéticos associados principalmente a infecções humanas bem como isolados com potencial zoonótico em amostras ambientais e obtidas de outros animais. Foi encontrado um alto percentual (25%) de amostras com grupos genéticos mistos e um elevado número de haplótipos distintos, indicando grande diversidade genética do parasito nessa região. Na segunda parte deste trabalho, foi realizado um estudo populacional com amostras clínicas de Giardia provenientes de hospital, creche e centro de controle de zoonoses e amostras ambientais de esgoto hospitalar, efluente de estação de tratamento de esgoto e amostras hídricas de importantes rios e córregos urbanos. As análises populacionais, com exceção das amostras caninas, evidenciaram grande similaridade genética entre essas populações de Giardia. Na terceira parte do presente trabalho, foi realizada uma busca por repetições microssatélites (SSRs) nos genomas publicados de Giardia para desenvolvimento, caracterização e avaliação de polimorfismo de novos marcadores microssatélites. Foram encontrados 506, 438, 402 e 507 microssatélites correspondentes aos genomas AI, AII, B e E, respectivamente. Foram selecionados 80 SSRs específicos aos grupos genéticos A, B e E (40, 20 e 20, respectivamente), além de 36 SSRs compartilhados entre os três genomas. A análise de amplificação confirmou a existência de marcadores específicos aos grupos genéticos A, B e E, além de marcadores compartilhados entre os grupos. A caracterização dos SSRs permitiu a detecção de 12 locos SSRs polimórficos do grupo genético A e sete locos SSRs polimórficos do grupo genético B. Dentre os marcadores compartilhados, o loco GduABE01 apresentou polimorfismo. Os locos polimórficos podem servir para futuros estudos populacionais e os marcadores desenvolvidos podem ser utilizados para identificação dos principais grupos genéticos de G. duodenalis em amostras clínicas e ambientais. Os resultados apresentados contribuem para um melhor entendimento sobre a diversidade genética do parasito bem como sobre a presença de grupos com potencial zoonóticos inter-relacionados em diferentes regiões. Os novos marcadores moleculares disponibilizados podem contribuir para novos estudos populacionais, promovendo melhor discriminação entre os genótipos e possibilitando assim identificar a contaminação e promover o rastreamento da doença
Abstract: Giardia duodenalis is a flagellate protozoan that that parasites humans and several domestic and wild animals. This parasite causes giardiasis, one of the most common waterborne diseases in the world responsible for, approximately 280 million cases per year. There is a great genetic diversity in this species and its isolates have been grouped into eight distinct genetic assemblages (A-H). While groups A and B parasitize different hosts and have zoonotic potential, groups C, D, E, F, G and H usually found in animals and show greater specificity to the parasitized host. Environmental contamination for Giardia has been widely reported however, most of these studies have been performed only at species level. The present study aimed to contribute to the knowledge of the genetic diversity of the species Giardia duodenalis. In the first chapter of this document, multilocus sequence-based genotyping using three gene loci assigned most of the samples as belonging to human genotypes although isolates with zoonotic potential have also been identified in environmental and non-human clinical samples. A high percentage (25%) of mixed assemblages and a high number of different haplotypes were detected, which indicates high genetic diversity of this parasite in this region. In the second chapter, a population genetics study was performed with clinical samples from hospital, day-car center and a center for zoonosis control of the city and environmental samples from hospital sewage, effluent of a wastewater treatment plant and important water samples from rivers and urban streams. With the exception of the canine population, population genetic analysis showed consistent similarity between clinical and environmental populations. In the last chapter, we performed a search for microsatellites (SSRs) in the published genomes of Giardia to develop and characterize the polymorphism of new microsatellite markers. Our group identified 506, 438, 402 and 507 microsatellites of the genomes AI, AII, B and E, respectively. We have selected 80 markers specific to the genetic assemblages A, B and E (40, 20 and 20, respectively) and 36 shared SSRs between the three genomes. Analysis of amplification reactions confirmed the existence of specific loci of each genetic assemblage as well as shared loci among assemblages. Characterization of all loci allowed the detection of 12 polymorphic loci for group A and seven polymorphic loci for group B. Among the shared markers, GduABE01 presented polymorphism. The polymorphic markers can be used in future population genetic studies and the developed markers can contribute to the identification of the main genetic assemblages of G. duodenalis in clinical and environmental samples. The results presented here contribute to a better understanding of the genetic diversity of the parasite as well as the presence of zoonotic potential genotypes, related in different regions. The new molecular markers provided can contribute with population genetic studies in a high level of discrimination that allows identifying the source of contamination and molecular tracking of the disease
Doutorado
Genetica de Microorganismos
Doutor em Genetica e Biologia Molecular

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Favennec, Loïc. "Contribution à l'étude de l'adhérence et de l'effet cytopathogène de Giardia intestinalis en présence de cellules de type entérocytaire : application de ce modèle à la détermination de la chimiosensibilité du parasite". Paris 5, 1990. http://www.theses.fr/1990PA05P603.

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Djamiatun, Kis. "In vitro studies on induction of lymphocyte and cytokine responses to the gut protozoans Giardia lamblia and Giardia muris". Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23882.

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In mice infected with 10$ sp4$ Giardia muris cysts, a peak lymphocyte proliferation in the spleen and Peyer's patches in response to Giardia extract occurred during the elimination and latent phases, respectively. This shows that the Peyer's patch cells are more responsive than the spleen to Giardia infection. Th2-type cytokines produced by Peyer's patch cells may play a protective role during the latent and acute phases. Th1-type cytokines may contribute to this production during the elimination phase. Cytokine production in response to Giardia extract in vitro was observed in mice immunized with this extract, but not in control mice. Therefore, Giardia antigen can induce cytokine production in vitro in a specific manner.

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Rojas, Hinostroza Giancarlo Eduardo. "Evaluación de tres primeros para la detección molecular de Giardia intestinalis en muestras fecales humanas". Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2014. https://hdl.handle.net/20.500.12672/4286.

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Introducción: Giardia intestinalis es el protozoario intestinal más común a nivel mundial y su diagnóstico parasitológico está basado en el examen microscópico, sin embargo, debido al carácter intermitente de la excreción del parásito en las heces el método puede revelar baja sensibilidad, esto ha motivado la búsqueda de nuevas alternativas de diagnóstico entre las que destacan aquellas que tiene como base la biología molecular. Objetivos: Evaluar 3 primeros para la detección molecular de G. intestinalis en muestras fecales. Diseño: Se realizó un estudio observacional, de corte transversal. Lugar: Instituto de Medicina Tropical “Daniel A. Carrión”, UNMSM. Procedimiento: Se evaluaron primers que amplifican las regiones de la beta-giardina y de la proteína de choque térmico 70 del ADN de G. intestinalis. Principales medidas de resultados: Se recolectó muestras fecales positivas y negativas a G. intestinales y a otros parásitos, las cuales fueron concentradas por centrifugación, luego almacenadas a -20°C y posteriormente analizadas mediante la técnica de PCR convencional. Resultados: Se estableció una temperatura de hibridación de 60°C para los primers de la beta-giardina y la proteína de choque térmico 70. La mezcla de reacción se estandarizó con las siguientes condiciones: Cl 2 Mg 1.5 mM, primers 0.6 µM, dNTPmix 0.3 mM y taq polimerasa 0.75 U. El límite de detección de los primeros fue de 87.3 ng/µL para beta-giardina, 359.5 ng/µL para GHSP70-1 y 24.1 ng/µL para GHSP70-2. Conclusiones: Se estableció una temperatura de hibridación y concentración de cloruro de magnesio común para los primers. Se observó un mejor límite de detección para el primer GHSP70-1 identificándose bandas en 7 diluciones con una sensibilidad y especificidad mayor que para el primer de la beta-giardina.
Introducción: Giardia intestinalis is the most common intestinal protozoan worldwide and its parasitologic diagnosis is based in microscopic examination; nonetheless, due to the intermittent parasites excretion in the feces, this method could reveal low sensitivity, this has motivated the search of new diagnostic alternatives such as those based on molecular biology. Goals: To assess 3 primers for the molecular detection of G. intestinalis in stool samples. Design: an observational, cross-sectional study was implemented. Settings: Tropical Medicine Institute “Daniel A. Carrión”, UNMSM. Procedures: We assessed primer that amplifies beta-giardin and heat-shock protein 70 of the G. intestinalis. Main measures of: Positives and negatives stool samples for G. intestinalis and for other parasites were collected and then concentrated by centrifugation and stored at -20°C for further analysis using conventional PCR. Results: A 60°C hybridization temperature was established for the primers of beta-giardin and the heat-shock protein 70. The master mix was standardized with the following conditions: 1.5mM Cl2Mg, 0.6 uM primers, 0.3mM dNTPmix and 0.75U Taq polimerasa. Limit detections were 87.3 ng/µL for beta-giardin, 359.5 ng/µL for GHSP70-1 and 24.1 ng/µL for GHSP70-2. Conclusions: We established a common hibridization temperature and a magnesium chloride common for the primers. A better detection limit was established for the primer GHSP70-1, identifying bands in seven dilutions with sensitivity and specificity higher for the beta-giardine primer. keywords: Giardia intestinalis, PCR, beta-giardina, heat-shock protein 70.
Tesis

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Jimenez, Artigas Juan Carlos. "Rôle des antigènes d'excrétion/sécrétion de giardia intestinalis dans la réponse immune et la pathogenèse de la giardiose". Lille 2, 2004. http://www.theses.fr/2004LIL2S008.

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Le parasite flagellé Giardia intestinalis (syn. G. Lamblia ou duodenalis) est responsable d’une infection chez l’homme et d’autres mammifères qui provoque une réponse inflammatoire transitoire de la muqueuse intestinale, associée parfois à malabsorption ou a des allergies digestives. Cependant les molécules impliquées dans ces phénomènes sont inconnues. Cette thèse tente d’étudier le rôle des protéines d’excrétion/sécrétion (E/S) de G. Intestinalis dans la réponse immune et la physiopathologie de la giardiose. L’administration par voie orale des protéines E/S chez la souris Balb/c stimule une réponse humorale (IgG1, IgG2, IgA et IgE), qui est parfois cytotoxique in vitro contre des trophozoïtes. Des bandes de 15, 63, 72 et 83 kDa ont été reconnues par les sérums des souris immunisées et caractérisée comme des cystéine-protéases. Les protéines E/S provoquent aussi des altérations histologiques de la muqueuse intestinale. L’immunisation systémique avec des antigènes E/S stimule une réponse de cytokines de type Th1/Th2 (IFN-, IL4, IL5 et IL10). Cependant, l’inhibition de leur activité cystéine-protéase induit une inhibition de la réponse immune. Nous avons observé que l’infection expérimentale par G. Intestinalis chez la souris stimule une réponse humorale et cellulaire plus intense vis-à-vis des antigènes E/S que des antigènes somatiques. Les patients infectés ont montré une intense réactivité sérique contre les antigènes E/S. L’ensemble de ces résultats suggère que les protéines E/S de G. Intestinalis, en particulier celles exprimant une activité cystéine-protéase, jouent un rôle important dans la réponse immune et la pathogenèse de la giardiose
Giardia intestinalis (syn. G. Lamblia or duodenalis) is a causative agent of intestinal infection in man and other mammals. This infection causes transient gastrointestinal complaints and allergic reactions. However, the parasite molecules related with these effects are unknown. In teh present study, we evaluated the role of excretory/secretory proteins (E/S) of G. Intestinalis In the immune response and the physiopathology of giardiasis. The oral administration of E/S proteins to Balb/c mice elicited a humoral response (IgG1, IgG2, IgA et IgE). The specific antibody exhibited a cytotoxic effect in vitro on the Giardia trophozoites. Proteins of 15, 63, 72 et 83 kDa were recognized by the serum of immunized mice and characterized as cystein-proteases. Histological perturbations after oral administration of E/S proteins were also observed. The systemic immunization with E/S proteins induced the production of cytokines Th1/Th2 (IFN-, IL4, IL5 et IL10). However, the inhibition of their enzymatic activity reduced the immune response. These results suggest that the enzymatic activity of E/S proteins is directly involved in the immune response. In infected mice, E/S proteins stimulated a higher immune response than somatic extracts. Consistently, serum samples from Giardia infected patients showed a higher reactivity against E/S proteins than against somatic antigen. Taken together, our results indicate that E/S proteins of G. Intestinalis, particularly, those with cysteine-protease activity, play a key role in the immun response, and contribute with the pathogenesis of Giardia infection

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Villazana-Kretzer, Diana L. "Giardia lamblia genomic and molecular analyses of flippase /". To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.

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Fernandes, Tayane Gonçalves. "Efeito da ciclohexilamina sobre trofozoítos de Giardia lamblia". Centro de Pesquisas Gonçalo Moniz, 2014. https://www.arca.fiocruz.br/handle/icict/9955.

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Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil
A giardíase é uma doença causada pelo protozoário flagelado Giardia lamblia, e sua sintomatologia é caracterizada pela eliminação de fezes esteatorréicas, dores abdominais e náuseas. Segundo o CDC estima-se que há cerca 1,2 milhões de casos por ano de giardíase, acometendo principalmente crianças em idade escolar. Atualmente, o tratamento da giardíase é realizado principalmente pelo uso do fármaco da família dos 5-nitromidazóis, metronidazol (Flagyl®), secnidazol e tinidazol em particular. Estes são confrontados em casos de resistência clínica causada pelo frequente uso inadequado do medicamento e/ou abandono do tratamento. Além disso, o metronidazol pode apresentar efeito carcinogênico em longo prazo em humanos. Desta forma, novos estudos com análogos e/ou inibidores de poliaminas podem levar à elucidação dos mecanismos de ação envolvidos, favorecendo o estabelecimento de novos regimes terapêuticos mais seguros e eficazes. Em nosso trabalho, foram testadas as substâncias ciclohexilamina (CHA) e o metronidazol que são produtos sintéticos, com o objetivo de avaliar os seus efeitos na proliferação celular, caracterização dos moduladores do metabolismo de poliaminas, avaliação nas mudanças no potencial redox e elucidação de seus possíveis mecanismos de ação nos trofozoítos de Giardia lamblia. Foi realizada uma avaliação da proliferação celular na presença de CHA para trofozoítos de Giardia lamblia, onde observamos que a substância demonstrou ter ação siginficativa apresentando um efeito dosedependente. Observamos que os trofozoítos de G. lamblia apresentam uma inibição significativa do crescimento em presença de concentrações milimolares do CHA, cujo IC50 em 72 horas foi de 1,646 mM. Ao avaliar a produção de lipoperóxidos nos trofozoítos foi observado o possível papel do CHA como promotor de estresse oxidativo neste parasito. Ao realizar microscopia eletrônica de varredura (MEV) os trofozoítos apresentaram morfologias completamente irregulares em diferentes concentrações da CHA, com internalização do disco adesivo, sendo corroborado com os resultados da microscopia eletrônica de transmissão (MET) que mostram o processo de encistamento seguido de necrose celular. Esses resultados indicam que a CHA é possível candidata para o uso terapêutico contra a giardíase.
Giardiasis is a disease caused by the flagellate protozoan Giardia lamblia, and its symptomatology is characterized by steatorrhea, abdominal pain and nausea. According to the CDC, an estimate number of 1.2 million cases of giardiasis happen every year, affecting especially schoolchildren.Nowadays, giardiasis treatment is based on drugs from the 5-nitroimidazole family, particularly metronidazole (Flagyl), secnidazole and tinidazole. Those drugs are indiscriminately used by the population, and it's not uncommon to find them causing clinical resistance due to inappropriate utilization and/or tratment abandon. Besides that, metronidazole can present longterm carcinogenic effect in humans. Thus, new studies with analogs and/or polyamines inhibitors can lead to the clarification of the drugs action mechanis, favouring the establishment of new, safer and more efficient therapeutic regimens.Our work tested cyclohexylamine (CHA) and metronidazole, wich are synthetic products, in order to evaluate their effects on cell proliferation and on changes in redox potential, characterize polyamines metabolism modulator and describe their possible action mechanisms on Giardia lamblia trophozoites. We evaluated Giardia lamblia trophozoites cell proliferation in the presence of CHA; it was observe that the substance shows significant action, presenting dose-dependent effect. We also observed that G. lamblia trophozoites presented significant growth inhibition when exposed to millimolar concentrations of CHA - its IC50 in 72 hours was 1,646mM. When assessed the lipoperoxides production in trophozoites, we observed a possible role of CHA as an oxidative stress promoter in the parasite.Under Scanning Electron Microscopy, trophozoites showed completely irregular morphologies in different CHA concentrations, with internalization of the adhesive disc; this results are corroborated by the Transmission Electron Microscopy results, wich showed the process of encystment followed by cell necrosis. This makes CHA a possible candidate for therapeutic use against giardiasis.

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França, Rita Borges. "Cryptosporidium spp., Giardia spp. e ovos de helmintos em esgoto hospitalar : destruição e analise de dano estrutural dos protozoarios apos o processo fotoeletroquimico". [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315635.

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Orientador: Regina Maura Bueno Franco
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: O efluente hospitalar apresenta, dentre seus componentes, organismos como vírus, bactérias, protozoários e helmintos, que ocasionam muitas doenças com implicações em saúde pública. Cryptosporidium spp. e Giardia spp. são protozoários parasitos com grande importância por sua veiculação hídrica e cujas formas infectantes são resistentes aos processos rotineiramente usados no tratamento de água e esgoto. A transmissão destes pode ocorrer com a ingestão dos oocistos e cistos eventualmente presentes na água e nos alimentos contaminados, por contato direto (pessoa a pessoa), por contato indireto (objetos contaminados), pelo contato sexual ou pode ser zoonótica. Os métodos mais utilizados para desinfecção em estações de tratamento são a aeração, cloração e irradiação por UV, mas a cloração, não é suficiente para eliminar oocistos de Cryptosporidium spp e cistos de Giardia spp. A tecnologia eletroquímica oferece um meio de tratamento eficiente para a oxidação. da carga orgânica e microbiológica degradando-as ou mineralizando-as. O presente trabalho teve por objetivos: (1) verificar a ocorrência natural de Cryptosporidium spp. e Giardia spp. em amostras de esgoto do Hospital de Clínicas de Campinas, utilizando o método, de centrífugo-concentração seguido de clarificação com éter e visualização por, imunofluorescência direta, durante o período de um ano; (2) verificar a presença de ovos e larvas de helmintos no esgoto hospitalar empregando a técnica da NOM (Norma Oficial Mexicana) e (3) avaliar a taxa de destruição e o dano estrutural causado em cistos e oocistos após o tratamento fotoeletroquímico. No esgoto hospitalar bruto 4,1 % e 58,3 % das amostras foram positivas para Cryptosporidium spp. e Giardia spp., respectivamente, sendo observada a concentração média de 2,7 x 103 oocistos/L e 3,8 x 105 cistos/L. Foi possível verificar a elevada presença de helmintos, com 90 % das amostras apresentando positividade e concentração de 5,8 x 104 ovos/L e 4,0 x 105 larvas/L. Os protozoários e helmintos presentes em altas concentrações no esgoto hospitalar representam uma séria ameaça à saúde humana. Para os ensaios com o tratamento fotoeletroquímico, amostras de 1 L de esgoto hospitalar foram artificialmente contaminadas com cistos e oocistos e, posteriormente, submetidas a esse tratamento em um reator de bancada, com tempos de exposição de 0,30, 60 e 90 minutos. Por meio das técnicas de imunofluorescência direta, microscopia de contraste de fase e microscopia eletrônica de varredura verificou-se o dano estrutural causado pela ação dos radicais hidroxila nesses protozoários patogênicos e a destruição dos mesmos. O tratamento fotoeletroquímico mostrou uma redução na concentração dos protozoários nos tempos de 30 e 60 minutos e após 90 minutos, nenhum cisto ou oocisto foi detectado. A presença do cloreto no efluente bruto (média de 45 mg/l) desencadeou uma potencializaçáo da ação de mecanismo do reator, gerando efeito associado com a eletrólise, dos radicais hidroxila com a formação de hipoclorito
Abstract: Hospital effluent presents organisms as virus, bacteria, protozoan and helminthes, that cause many iIInesses with implications in public health. Cryptosporidium spp. and Giardia spp. are parasites with waterborne importance and its cysts and oocysts are resistant to the routinely processes used in water treatment. Their transmission can occur by oocysts and cysts ingestion in the water and contaminated foods, by direct contact (person the person), by indirect contact (contaminated objects), by sexual contact or zoonotic. The methods used for disinfection and treatment of sewage are aeration, chlorination and irradiation of ultraviolet light, but the treatment by chlorination is not enough to inactivate Cryptosporidium spp. oocyst and Giardia spp. cysts. The electrochemical technology offers an efficient treatment for the oxidation of organic and microbiological load, degrading and mineralizing them. The present work had as objectives: (1) to verify the natural occurrence of Cryptosporidium spp. and Giardia spp. in samples of Clinical Hospital sewage from Unicamp using centrifugal concentration followed by clarification with ether method and visualization by immunoflourescence assay, during one year, (2) to verify the presence of eggs and larvae of helminthes in the hospital sewage by NOM (Mexican Official Norm) technique and (3) to evaluate the destruction rate and the structural damage caused in cysts and oocysts by photoelectrochemical treatment. In raw hospital sewage 4.1 % and 58.3% of the samples were positive for Cryptosporidium spp. and Giardia spp., respectively, with concentrations of 2.7 x 103 oocysts/L and 3.8 x 105 cysts/L. The high presence of helminthes, 90% positive, with 5.8 x 104 eggs/L and 4.0 x 105 larvae/L and protozoan in hospital sewage represent a serious threat to human being health. For the assays with the photoelectrochemical treatment, samples of 1 L of hospital sewage artificially contaminated with cysts and oocysts ! were submitted to this treatment in a bench reactor, with times of exposition of 0, 30, 60 and 90 minutes. By the techniques of immunofluorescence assays, microscopy of phase contrast and scanning electronic microscopy, the structural damage and destruction were observed, caused by hydroxyl radicals in these pathogenic protozoans. The photoelectrochemical treatment showed a concentration reduction of the protozoan in 30 and 60 minutes, and after 90 minutes no cyst or oocysts were detected. The chloride present in raw effluent (average of 45 rng/L) unchained a potential action of the reactor mechanism, generating an effect associated with electrolysis of the hydroxyl radicals with production of hypochlorite
Mestrado
Parasitologia
Mestre em Parasitologia

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Carvalho, Thaís Batista de [UNESP]. "Identificação e caracterização dos produtos de excreção/secreção de trofozóitos de Giardia duodenalis". Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/89970.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Universidade Estadual Paulista (UNESP)
O presente estudo foi desenvolvido com o objetivo de identificar e caracterizar os produtos de excreção/ secreção (PE/S) de trofozoítos de Giardia duodenalis de uma cepa axênica isolada no Brasil (BTU-11), tendo por referência a cepa padrão Portland 1 (P-1) isolada nos Estados Unidos. Os PE/S foram obtidos a partir dos sobrenadantes de cultura de trofozoítos mantidos em meio RPMI por 6 horas a 37oC. Os PE/S de cada cepa foram analisados quanto ao perfil eletroforético em géis de poliacrilamida (SDSPAGE) e a atividade proteolítica foi avaliada em géis contendo gelatina e colágeno tipo I a 0,2% e em ensaios empregando hemoglobina a 0,1%. A caracterização das proteases dos PE/S foi realizada em ensaios para avaliar o efeito de inibidores sintéticos de cisteína, serina, metalo e aspartil proteases sobre a degradação de cada substrato testado. A análise dos perfis protéicos revelou padrões simples, porém distintos quanto ao número de bandas de proteínas, visualizando nos PE/S das cepas P-1 e BTU-11, respectivamente, seis e quatro bandas com massas moleculares distribuídas na faixa de 123 a 28 kDa. Quanto à atividade proteolítica, todos os substratos foram degradados por enzimas presentes nos PE/S. A atividade gelatinolítica foi observada na faixa de 77 a 18 kDa, destacando-se seis bandas evidentes de aproximadamente 77, 66, 54, 52, 21 e 18 kDa. A degradação do colágeno foi detectada na faixa de 145 a 18 kDa, sendo que as zonas de proteólise de maior evidência foram observada nas faixas de 145 a 82 kDa e de 56 a 34 kDa, onde destacam-se as bandas de 145, 96, 82 e 34 kDa. A análise dos padrões de hidrólise da hemoglobina demonstrou similaridade entre as cepas e revelou degradação total da cadeia dimérica e lise parcial da cadeia monomérica. A atividade gelatinolítica e...
The present investigation was undertaken to examine the protease activity in excretory/secretory (E/S) products of Giardia duodenalis trophozoites of an axenic Brazilian strain (BTU-11) and the reference strain Portland 1 (P1). E/S products in conditioned medium by trophozoites of each strain were tested in SDS-polyacrylamide gel electrophoresis for the protein profiles, and the proteases activity was analyzed using substrate gelatin and collagen impregnated SDS-PAGE and haemoglobin assay. The proteases characterization was based on inhibition assays including synthetic inhibitors for cysteine, serine, metallo and aspartic proteases. Electrophoresis analysis of E/S products revealed a banding pattern composed by few bands (4-6 bands) in the migration region of 123 to 28 kDa. Proteolytic products were detected in the conditioned medium by trophozoites of both assayed strains. In the gels containing copolymerized gelatin and collagen, E/S products promoted degradation of both substrates and the most evident proteolysis zones were distributed in the migration regions of 77 to 18 kDa and 145 to 18 kDa, respectively, in the patterns of gelatinolytic and collagenolytic activities. Degradation of haemoglobin was also observed, and the pattern of hydrolysis was similar in both E/S products assayed. Inhibiton assays showed that the main proteolytic activity in E/S products is due to cysteine proteases although the presence of serine proteases was also indicated, mainly in the hydrolysis of haemoglobin. These observations are relevants, especially ...(Complete abstract click electronic access below)

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Davey, Robert Andrew. "Characterization of nucleoside transport in the intestinal protozoan parasite Giardia intestinalis". Title page, contents and abstract only, 1994. http://web4.library.adelaide.edu.au/theses/09PH/09phd248.pdf.

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Includes copies of other papers co-authored by the author at end of thesis. Includes bibliographical references (leaves 241-265) A rapid sampling technique has been adapted and used to measure nucleoside transport in a human-derived isolate of the intestinal protozoan parasite Giardia intestinalis (syn. G. lamblia)

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Lenaghan, Scott Sundermann Christine A. "Molecular responses of Giardia lamblia to gamma-irradiation". Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/SUMMER/Biological_Sciences/Dissertation/Lenaghan_Scott_38.pdf.

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Borucke, Michael Joseph 1979. "Filtration of Giardia cysts from Haitian drinking water". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84311.

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Aquino, Monally Conceição Costa de. "Caracterização molecular de Giardia spp. em bezerros bubalinos". Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/152926.

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Outra
Giardia duodenalis é um protozoário flagelado que coloniza o trato intestinal de hospedeiros vertebrados. A caracterização molecular de G. duodenalis revolucionou a compreensão da taxonomia, diversidade genética e epidemiologia da giardíase em seres humanos e animais. Em nosso estudo, realizamos a caracterização molecular de G. duodenalis em bezerros bubalinos do Estado de São Paulo, Brasil. Assim, foram colhidas 183 amostras fecais de animais da raça Murrah, com até seis meses de idade. Estas amostras foram examinadas por meio da reação em cadeia pela polimerase tipo para amplificação da subunidade menor do gene do RNA ribossômico, todas as amostras positivas por esse gene, foram caracterizadas para amplificação parcial dos genes beta-giardina, glutamato desidrogenase e triosefosfato isomerase. G. duodenalis foi verificada em 6,56% das amostras fecais e por meio da análise das sequências, verificou-se 100% de similaridade genética com “assemblage” E. Esta foi a primeira detecção de G. duodenalis “assemblage” E em bezerros bubalinos no Brasil.
Giardia duodenalis is a flagellated protozoan that colonizes the intestinal tract of vertebrate hosts. A molecular characterization of G. duodenalis revolutionized an understanding of the taxonomy, genetic diversity and epidemiology of giardiasis in humans and animals. In our stud, we performed the molecularly characterization of Giardia duodenalis in buffalo calves from State of São Paulo, Brazil. Then, 183 fecal samples of Murrah buffaloes were collected up to six months of age. These samples were examined by nested polymerase chain reaction for parcial amplification of the small subunit of the ribosomal RNA gene. All G. duodenalis-positive samples were characterized by beta-giardin, glutamate dehydrogenase and triosephosphate isomerase genes. G. duodenalis was detected in 6,56% of the faecal samples, and sequence analysis showed 100% genetic similarity with assemblage E. This was the first detection of G. duodenalis assemblage E in buffalo calves in Brazil.

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Oliveira, Ana Isabel de Freitas Tavares de. "Caracterização genética de isolados axénicos de Giardia lamblia". Master's thesis, Universidade de Aveiro, 2010. http://hdl.handle.net/10773/3518.

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Mestrado em Microbiologia Molecular
As parasitoses intestinais continuam a constituir um grave problema de saúde pública, a nível mundial. Giardia lamblia, também denominada G. duodenalis ou G. intestinalis é um protozoário frequentemente responsável por patologias entéricas, representando, nos seres humanos, o principal agente causal de gastroenterites parasitárias. A giardiose é, assim, tida como a mais frequente das parasitoses de índole protozoária. Tendo em conta a escassez de trabalhos, em Portugal, sobre esta patologia, com este trabalho pretende-se contribuir para o enriquecimento do conhecimento nesta área. Assim, efectuou-se um estudo epidemiológico, nas cidades do Porto e Viseu, no qual foram pesquisados diversos parasitas, entre os quais, G. lamblia. A inexistência de isolados levou à caracterização molecular, por PCR – RFLP, de outros, criopreservados, o que conduziu à optimização de um protocolo que poderá ser usado rotineiramente no Laboratório de Investigação.
Parasitic diseases continue, knowadays, to be a major concern and health problem, all over the world. The protozoa Giardia lamblia (also kwoned as G. duodenalis or G. intestinalis) is responsible, in humans, for the most of parasitic gastroenteritis. Giardiasis is, therefore, the parasitic gastric infection with the higher prevalence. The lack of published articles and studies, in Portugal, about this organism and its pathology, dictates the pertinence of this work. With it we wish to enrich the knowledge in this area. Therefore, a field study was performed to access the prevalence of several parasites (within those was G. lamblia), on the cities of Porto and Viseu. As a consequence of the results of this study (concerning G. lamblia) the work changed its course. The next step consisted in the molecular characterization by PCR – RFLP, of isolates previously axenized and criopreserved, that lead to a protocol optimization, that can be, therefore, used in our laboratory practice.

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Sullivan-Madore, Mary 1959. "Detection of Cryptosporidium and Giardia in environmental waters". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191916.

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Cryptosporidium and Giardia, both enteric parasites, have been shown to cause waterborne disease. Methods were developed to investigate the occurrence of Cryptosporidium and Giardia in large volumes of water. Environmental waters were filtered, eluted from a filter and concentrated using centrifugation. Antifoam was employed after homogenization of the resultant pellet suspension for faster oocyst recoveries. This suspension was then layered onto a density gradient to separate the parasites from the sediment. The gradient layer containing any potential parasites was directly labeled on the membrane filter with fluorescein labeled monoclonal antibodies. These filters were then examined by immunofluorescence. Using this technique, Cryptosporidium oocysts were detected in raw sewage, treated sewage, backflush waters, and surface waters. Cryptosporidium was three magnitudes higher in concentration than Giardia in raw sewage. Since Cryptosporidium is frequently present in environmental waters, and in significantly higher numbers than Giardia, it potentially could be transmitted by this route.

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Allmen, Nicole Eva von. "Molecular analysis of antigenic variation in Giardia lamblia and influence of intestinal inflammatory reactions on a Giardia lamblia infection in mice /". [S.l.] : [s.n.], 2005. http://www.zb.unibe.ch/download/eldiss/05vonallmen_n.pdf.

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Maux, Mélinda. "Détection et estimation de la viabilité des kystes de Giardia par biologie moléculaire en vue d'une application à l'analyse de prélèvements de l'environnement". Nancy 1, 2003. http://www.theses.fr/2003NAN12515.

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L'évaluation du risque parasitaire passe par le développement de stratégies d'analyses efficaces, sensibles et spécifiques qui peuvent permettre non seulement de détecter le parasite, mais aussi d'estimer sa viabilité faute de pouvoir disposer d'un outil fiable pour déterminer son pouvoir infectieux. Parmi lestrois protozoaires les plus fréquemment retrouvés au niveau mondial, Giardia est présent sous la forme de kyste dans l'environnement. En fonction de ces éléments, cette étude a pour objectif de développer des outils de biologie moléculaire pour réaliser la détection des kystes de Giardia et l'évaluation de leur viabilité. La première partie de ce travail a permis de définir une méthode d'amplification de l' ADN par semi-nested PCR analytique et de l' ARN par RT semi-nested PCR analytique de kystes de Giardia purifiés à partir de selles de malades, en partant de trois gènes cibles et spécifiques de Giardia: l'HSP 70,1' ADHE et la Giardine. Aucun fragment amplifié n'a été obtenu avec les amorces HSP 70, des produits d'amplification ont été observés à la suite d'une semi-nested PCR avec le gène de l' ADHE, et pour la dernière cible, la Giardine, des résultats positifs sont enregistrés aussi bien en PCR qu'en RT-PCR. Pour parvenir à ces résultats, un protocole d'extraction pour chaque acide nucléique (ADN et ARN), des conditions optimales d'amplification pour chaque cible (HSP, ADHE et Giardine), ainsi qu'un traitement de l'extrait ARN par une DNase pour s'affranchir de l'amplification exclusive de cet acide nucléique ont été successivement sélectionnés. Dans nos conditions d'expérimentation, le seuil de détection de la semi-nested PCR est fixé pour la Giardine à 6 kystes et de la RT semi-nested PCR à 3 kystes. En partant de ces outils d'analyses, des études de survies en fonction de la température et d'impactd'un choc thermique sur la morphologie et l'expression des kystes de Giardia ont été réalisées. Les résultats d'estimation de la viabilité par RT-PCR analytique ont également été comparés à ceux obtenus en microscopie optique après marquage des kystes par des colorants vitaux. Globalement, quelles que soient les conditions d'incubation (température et temps), nos expérimentations ont démontré la persistance de l' ADN et de l' ARN par PCR et RT -PCR respectivement. L'estimation de la viabilité déterminée par RT-PCR n'est pas cohérente avec celle issue de l'observation au microscope optique en épi fluorescence qui permet d'enregistrer une baisse de la viabilité d'autant plus importante que la température est éloignée de l'intervalle 4-20ʿC et que le temps d'incubation est important. D'après ces résultats, la disponibilité de l'ADN et de l'ARN ne semble pas être diminuée par le stockage des kystes de Giardia aux différentes températures, probablement grâce à la persistance des acides nucléiques et/ou l'absence de modification dans le métabolisme de l' ARNm. Dans une seconde partie du travail, à partir des acides nucléiques des mêmes parasites, les conditions d'amplification de l' ADN et de l' ARN, respectivement en PCR et en RT-PCR quantitatives, ont été définies en prenant toujours pour cible la séquence de la Giardine. A l'issue de l'optimisation des conditions d'amplification, le protocole de PCR quantitative est validé sur la base d'une reproductibilité supérieure à 95 %, d'un rendement estimé à 88% et d'un seuil de détection fixé à 6 kystes de Giardia. Dans le cas de la RT-PCR quantitative, le traitement enzymatique par la DNase ne modifie ni le rendement (94 %) ni la sensibilité de la détection. Il permet d'assurer, avec une variabilité inférieure à 5 %,l'amplification exclusive de l' ARN à partir de 3 kystes de Giardia. En utilisant la méthodologie Jle PCR et RT-PCR quantitatives développée et l'observation au microscope optique en épifluorescence, les mêmes études de survies en fonction de la température et de l'impact d'un choc thermique sur la morphologie et l'expression des kystes de Giardia ont été réalisées. Les résultats de l'estimation de la viabilité ont également été comparés successivement à ceux obtenus en microscopie optique. Cette fois, la persistance de l' ADN est vérifiée plus précisément par des valeurs d'abattement proche de zéro et quelles que soient les conditions d'expérimentation. Concernant l' ARNm, les résultats de RT -PCR permettent dans certaines conditions d'enregistrer de faibles abattements, alors qu'à l'issue de l'examen en microscopie optique il est possible de vérifier l'absence de kystes viables. Nos expérimentations ont démontré qu'il était possible d'amplifier de façon sensible et spécifique le génome de Giardia (ARN et ADN) aussi bien par PCR analytique que par PCR quantitative. En revanche pour l'évaluation de la viabilité des kystes de Giardia, seule la PCR quantitative fournit les informations nécessaires pour apprécier le pouvoir infectieux.

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Santos, Samuel Ricardo dos 1980. "Fluorescência retardada em protozoários : Giardia intestinalis e Cryptosporidium parvum". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257131.

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Orientadores: José Euclides Stipp Paterniani, Cristiano de Mello Gallep
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
Made available in DSpace on 2018-08-25T21:52:58Z (GMT). No. of bitstreams: 1 Santos_SamuelRicardodos_D.pdf: 51294263 bytes, checksum: 55a8bb93513a62aa29e85fe9467412c6 (MD5) Previous issue date: 2014
Resumo: Giardia spp. e Cryptosporidium spp. são organismos desafiadores em monitoramento ambiental, podendo afetar os seres humanos e os animais com grandes impactos na saúde pública. Métodos para detectar esses organismos são descritos na literatura ¿ p.ex.: o método EPA 1623.1. No entanto, muitos não são capazes de detectar a viabilidade destes parasitos. Este trabalho avaliou o uso de marcadores fluorescentes combinados com a técnica de detecção de fluorescência retardada na detecção de viabilidade de Giardia intestinalis e Cryptosporidium parvum. Testes de incubação com 6-carboxifluorceina-succinimidil-diacetato-éster (CFDA-SE), C12-resazurina e SYTOX Green foram desenvolvidos com cistos de G. intestinalis e oocistos de C. parvum. Medidas de fluorescência retardada em câmara escura projetada e em dispositivo comercial foram aplicados em amostras purificadas e concentradas de G. intestinalis após incubação com CFDA-SE. Grupos contendo cistos vivos e infecciosos, mortos a 100° C, estressados com luz UV-C e envelhecidos foram analisados via fluorescência retardada e microscopia de epifluorescência em oito séries experimentais. Os resultados demonstram que (oo)cistos vivos e infecciosos não são marcados com os marcadores fluorescentes. Dupla marcação em (oo)cistos mortos é observada após 30 minutos de incubação com C12-resazurina 5,0 ?M e SYTOX Green 100 nM. (Oo)cistos mortos apresentam marcação verde após incubação de CFDA-SE 5,0 ?M. O envelhecimento da amostra foi acompanhado pelo aumento da taxa de marcação celular com cistos apresentando ~50% de marcação aos 30 dias de idade e ~100% aos 50 dias de idade. Testes com fluorescência retardada demonstram que cistos vivos e com idade inferior a 20 dias apresentam intensidades superiores aos cistos mortos e estressados após excitação com 365 nm. A excitação com 365 nm apresentou correlação R2 > 95% após análise de cinética de decaimento com modelo exponencial de segunda ordem. Os dados indicam que o decaimento da fluorescência retardada é acompanhado por duas componentes k1 e k2 onde k2 = 5?k1, estando estas conectadas com as condições fisiológicas da Giardia. O procedimento pode ser efetuado em 10 passos laboratoriais em aproximadamente 60 minutos de análise. A fluorescência retardada apresenta futuro promissor na análise de viabilidade de parasitos em amostras purificadas
Abstract: Giardia spp. and Cryptosporidium spp. are challenging and important organisms in modern environmental monitoring. These protozoa can affect humans and animals seriously, as reflection of sanitation problems in water quality control, with huge impact over economics and public health. Methods to detect such organisms are well described in literature - i.e. the EPA Method 1623.1 and AWWA 2012. But those ones are not able to detect infectivity. For that, the usual procedures include infection of animal model leading to at least one week for confirming infectivity. Some research with dye probes are being developed in order to provide useful, reliable and low cost procedures for detection of protozoa viability, i.e. enabling to distinguish dead samples cells from living ones. This work describes the screening tests for viability detection of protozoa samples - Giardia intestinalis and Cryptosporidium parvum - using carboxifluorcein-succinimidyl-diacetate-ester (CFDA-SE), C12-resazurin and SYTOX Green. Living, heat-killed and UV-C stressed (oo)cysts were analyzed using these chemical probes. G. intestinalis in concentrated samples and stained with CFDA-SE were analysed by fluorescence imaging as well as by delayed fluorescence (DF) after UV-A and white-light excitation. The weak DF profiles were detected in photon-counting setups, in 8 series of tests for intact, for heat-killed and for UV-C-stressed samples are shown. Results show that fresh, i.e. living and viable (oo)cysts cannot be stained by the mentioned neither with CFDA-SE nor C12-resazurin and SYTOX Green dyes. Double-marked (oo)cysts are observed when C12-resazurin and SYTOX Green are applied to old cysts as well to dead ones. Aged samples show increasing number of stained organisms: 30-day-old with ~50% while samples older than 50 days with almost 100% marked. Intact samples present stronger fluorescence and DF than the stressed ones, with good replication after UV-A excitation. After excitation @365nm samples present DF better fitted by double exponential decay kinetics, with the decay constant k2 five times higher than the k1 constant. The procedure can be easily reproduced in 10 steps, taking around 1h of laboratorial work with purified samples
Doutorado
Agua e Solo
Doutor em Engenharia Agrícola

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Salih, Baraah. "A comparative study of immunofluorescence, zinc sulphate centrifugal flotation and FASTest®GIARDIA strip for detection of Giardia in dogs and cats". Thesis, Uppsala universitet, Institutionen för kvinnors och barns hälsa, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-357635.

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Giardia intestinalis is the most common parasite found in dogs and cats. It is traditionally diagnosed using a microscope. These methods include direct immunofluorescence, DIF, and zinc sulphate centrifugal flotation, ZnSO4 C-flotation. However, there are commercially available SNAP tests such as the FASTest® GIARDIA strip that is often used by dogs and cats owner to detect Giardia. The aim of this study was to compare the sensitivity, cost and labor intensity of these three methods for detection of Giardia. To investigate this, 150 samples from dogs and cats were examined at the National Veterinary Institute in Sweden. The samples were a mixture of diarrheic and non-diarrheic stool. Of the 150 stool samples 100 samples were examined with FASTest® GIARDIA strip while 150 samples were examined with DIF and ZnSO4 C-flotation. The results indicated that FASTest® GIARDIA strip had a sensitivity of 66.18 %, a cost of 100 Swedish crowns (SEK) per sample and was the easiest test to use. ZnSO4 C-flotation had a sensitivity of 89.90 %, cost 418.75 SEK and took about 15 minutes to perform. DIF had 100 % sensitivity and specificity and due to that it was used as a standard reference method. The cost for DIF was 300 SEK and took more than an hour to perform per sample. The conclusion from this study is that, FASTest® GIARDIA strip is not a recommended test for detection of Giardia despite their low cost and easiness to use. DIF and ZnSO4 C-flotation remain a better diagnostic option for detection of Giardia.

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Rust, Colleen Frances. "Removal of the human pathogen Giardia intestinales from groundwater". Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/C_Rust_120506.pdf.

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Grignard, Lynn. "DNA replication initiation in the protozoan parasite Giardia lamblia". Thesis, St George's, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.559383.

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In this thesis the Giardia lamblia origin recognition proteins, GiOrc1/cdc6 and GiOrc4 (GiORC) are under investigation. We set out to do a basic molecular characterisation of the GiORC proteins as well as determining origins of DNA replication in the protozoan parasite. The sequences for both GiORC were successfully identified from genome databases and analysed using bioinformatics tools. Furthermore, the GiORC proteins were successfully over-expressed in a bacterial system. In a first strategy, pure protein with or without an affinity tag was used for antibody production, for the use in western blotting, immuno precipitation (interacting partners), chromatin immuno precipitation (identification of origins of DNA replication) and microscopy (protein localisation). Three antibodies against the GiORC were generated. Unfortunately, none of the antibodies recognised the native GiORC. GST-tagged GiOrc4 for GST pull down experiments was used to identify interacting partners, without success. In a second strategy, the GiORC were cloned into Giardia over-expression vectors. Two novel vectors were constructed, pV5.pac and ProtORCtet. Both vectors had not been used previously in the parasite. In addition GiORC sequences were cloned into pGFP.pac, a GFP fusion vector. Six different constructs, three for each GiORC sequence, were generated. In four of the constructs, GiORC/pGFP.pac and GiORC/pV5.pac, expression could not be detected in transgenic cell lines. In ProtOrc4tet, expression of V51HA tagged GiOrc4 was detected by western blot and immuno fluorescence microscopy. In a third strategy, the interaction of GiOrcl/cdc6 and GiOrc4 was shown by yeast two hybrid. We were also interested in the effects of GiORC gene knockdown by RNA interference. The results from the DNA based RNAi vector, however, were inconclusive. In summary, we managed to compile information on the DNA replication proteins m Giardia lamblia and to set up additional tools to further study DNA replication initiation in the parasite.

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Zourmpanou, Danai Maura. "Studies on the mitochondrial remnant organelles of Giardia intestinalis". Thesis, University of London, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.588756.

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Giardia intestinalis is a protozoan parasite that causes the gastrointestinal disease giardiasis, one of the most frequent parasitic infections worldwide. Giardia was for many years considered to be a primitive or early diverging eukaryote because it lacks organelles typically present in eukaryotes such as classical mitochondria, nucleoli and peroxisomes. On the other hand, it has a cytoskeleton, an endomembrane system and subcellular protein sorting functions of higher cells, which suggest it is a complex and highly developed cell. It has recently been shown that two giardial mitochondrial- related proteins, the IscU and IscS, eo-localize inside a double-membrane organelle of mitochondrial origin, the mitosome. This thesis presents evidence, from in vivo and in vitro protein import studies, that Giardia mitosomes also harbor another mitochondrion-related protein, ferredoxin, and that despite their advanced state of reductive evolution, mitosomes have retained saturable presequence-dependent and presequence-independent protein import pathways analogous to those that operate in mammalian mitochondria. Giardia also encodes a Fe-hydrogenase gene, even though it lacks recognizable hydrogenosomes. The cytosolic localization of the Fe- hydrogenase observed in this study allows the conclusion that the remnant organelles of Giardia are not hydrogenosomes, but mitosomes. The development of an in vitro protein import assay using highly enriched intact mitosomes from Giardia trophozoites and the radiolabeled precursor Fd protein is also reported. The purification method devised in this study yielded a highly enriched, intact mitosomal population competent for protein import. The mitosomal protein import assay demonstrated the proteolytic removal of the targeting peptide of Fd upon organelle import, which is a functional feature of the mitochondrial and hydrogenosomal protein import systems. These results are strong evidence that G. intestinalis possess a mitosomal protein import machinery similar to that of mitochondria and hydrogenosomes, providing further evidence that these three organelles arose from a common endosymbiont.

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CTORZA, FRANCINE. "Arthrite reactive a giardia : etude a propos d'un cas". Aix-Marseille 2, 1988. http://www.theses.fr/1988AIX20482.

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Štefanić, Saša. "Biogenesis and dynamics of Golgi equivalents in "Giardia lamblia" /". Bern : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.

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Steuart, Robert. "Comparative proteomics of Giardia duodenalis from humans and cattle". Thesis, Steuart, Robert (2012) Comparative proteomics of Giardia duodenalis from humans and cattle. PhD thesis, Murdoch University, 2012. https://researchrepository.murdoch.edu.au/id/eprint/12943/.

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Giardia duodenalis is a gastrointestinal parasite capable of infecting humans as well domesticated animals, for example cattle. There are seven distinct genetic groups, termed assemblages A-G, with assemblages A and B able to infect humans and assemblage E specific to livestock, including cattle. The level of genetic variation between the assemblages has been studied over multiple loci and the phylogenetic relationship between these assemblages is well known. There is however, little information available on the protein differences between the assemblages. Proteins of the human infective assemblages A and B were compared using SDS-PAGE and 2D-PAGE to determine proteins of difference. Proteins determined to be assemblage-specific were then identified using mass spectrometry. In total, eleven proteins of difference were identified between assemblages A and B. Four proteins; alpha 2 giardin, GASP-180, UPL-1 and GLORF-C4, were chosen for further characterisation. Genetic analysis confirmed that alpha 2 giardin is absent from assemblage B and that the size variation seen in the GASP-180 protein is mirrored by a series of indels in a portion of the gene sequence. The UPL-1 gene did not show any variation indicating the protein variation seen is likely due to post translational modification. The GLORF-C4 protein, which is involved in the formation of cysts, was only identified in assemblage B. Therefore, the ability of assemblages A and B to undergo the encystment process was also studied. The assemblage B isolates produced fully formed cysts 24 hrs faster than assemblage A isolates. Analysis of levels of GLORF-C4 mRNA indicated that the gene is constitutively expressed in assemblage B and induced in assemblage A. The proteins of the human infective assemblages were then compared to those of the livestock infective assemblage E, with thirteen protein variants identified, the majority of which are the same as those identified between assemblages A and B. The proteins identified in this study are the first protein variants documented between assemblages of G. duodenalis.

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