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1
Thomas, Christina. "Gonder Ceramic Arts, Inc. eine kulturwissenschaftliche und terminologische Untersuchung mit Fokus auf keramischen Glasuren." Trier Wiss. Verl. Trier, 2005. http://deposit.ddb.de/cgi-bin/dokserv?id=2776340&prov=M&dok_var=1&dok_ext=htm.
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Bailey, Kenneth D. "Report of an internship with the Bureau of Land Management for the Falcon to Gonder construction project." Oxford, Ohio : Miami University, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1098144755.
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Bailey, Kenneth D. "REPROT OF AN INTERNSHIP WITH THE BUREAU OF LAND MANAGEMENT FOR THE FALCON TO GONDER CONSTRUCTION PROJECT." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1098144755.
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Gonder, Silke [Verfasser], and Wilhelm E. [Akademischer Betreuer] Winterhager. "Terra incognita: Studien zu Dorf und Künstlerkolonie am Beispiel Willingshausen in der Schwalm. Fremdheitserfahrungen - gelebte Gemeinschaft - wechselseitiger Einfluss / Silke Gonder ; Betreuer: Wilhelm E. Winterhager." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1216242267/34.
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Guebreyesus, Namouna. "Les transferts fonciers dans un domaine ecclésiastique à Gondär (Ethiopie) au XVIIIe siècle." Thesis, Paris, EHESS, 2017. http://www.theses.fr/2017EHES0169/document.
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Gondär est établie comme une ville royale au milieu du XVIIe siècle. Elle se situe au croisement des voies commerciales et proche des terres les plus fertiles. Les rois de Gondär instituent de nombreuses églises qu’ils dotent de domaines. Ils honorent ainsi l’engagement fondateur de leur dynastie selon lequel une partie des terres du royaume est réservée aux religieux. Les églises reçoivent par donation des terres déjà occupées, par réajustement des bénéfices domaniaux. Leurs biens-fonds sont désignés gwәlt, et elles ne peuvent en disposer par la vente, la donation ou la constitution de sûreté. Des clercs obtiennent des concessions appelées rim-s sur les terres des églises. Les ventes de ces rim-s sont, à l’inverse de celles des gwәlt-s, reportées par milliers à Gondär. L’ampleur des transferts fonciers est sans précédent connu dans l’histoire éthiopienne. Pour comprendre ce qu’ils signifient, les concepts de gwәlt et de rim sont définis. Leur régime ainsi que les contextes économiques, sociaux et politiques dans lesquels ils évoluent sont déterminés. Le travail proposé procède en prenant comme cas d’étude un recueil d’actes provenant de l’église de Ḥamärä Noḫ fondée en 1709. Les textes de Ḥamärä Noḫ sont interprétés au moyen de sources contemporaines. L’argumentation considère les actes issus d’autres églises, les commentaires de loi préparés par des clercs de Gondär ainsi que les chroniques royales. Elle intègre aussi les apports des écrits de voyageurs européens.Cette étude essaye de démontrer que le phénomène de ventes de rim-s à Gondär ne marque pas le début d’un marché foncier. Les échanges n’ont pas leur cause en un libre cours de l’offre et de la demande. Ils sont bien plus provoqués par l’endettement des clercs et leur besoin de crédit. Les transferts renforcent les inégalités sociales et les avantages seigneuriaux d’une catégorie de gens proche du pouvoirA royal city called Gondär was established in the middle of the XVIIth century in Ethiopia. The city was crossed by trade routes and was close to the most fertile regions. The kings of Gondär were founders of a number of churches endowed with land. The agreement that enabled the royal dynasty to seize power and that reserved a portion of the kingdom to the clergy was thus honoured. Churches received occupied land by a royal donation that reajusted domanial entitlments. Their endowments (gwәlt) were in principle considered perpetual, and this prevented the transfer of the lands by sale, donation or as a security. Clerics received individual holdings called rim from the churches’ domains. Contrary to gwәlt, rim land was transfered in thousands of sales registered in Gondär.The propensity of land transfers was without a known precedent in Ethiopian history. To understand this phenomenon, the concepts of gwәlt and rim will be defined. Their regime as well as the economic, social and political context within which they evolved will also be determined.The thesis will proceed in taking as its case study the church of Ḥamärä Noḫ founded in 1709. The texts from Ḥamärä Noḫ will be interpreted using contemporary sources. The argument will use documentation from other churches, legal commentaries drafted by clerics from Gondär, royal chronicles and European travellers’ views.The study aims to demonstrate that rim sales from Gondär cannot be seen as the beginning of land marketability. The transfers are not the result of an open market where demand and supply meet. They are rather caused by an indebtedness of clerics and their need for credit. As a result of these sales, social inequalities are aggravated and a category of people, close to power, secure their seigniorial advantages
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Bubáková, Dana. "Michel Gondry." Master's thesis, Akademie múzických umění v Praze. Filmová a televizní fakulta AMU. Knihovna, 2009. http://www.nusl.cz/ntk/nusl-79069.
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Mason, Sam. "Toxoplasma gondii in sheep." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556024.
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Toxoplasma gondii infects sheep horizontally (from cat faeces) or vertically (transplacentally). Vertically infected lambs sometimes die. Here, transmission and performance impacts were considered in one Charollais flock and one Swaledale flock. B1-PCR was performed on umbilical cord, heart and brain. MAT was performed on blood and pleural effusion. IgG-ELISA was performed on colostrum. B1-PCR was more sensitive than four other methods, producing a band in 50% of replicates when each replicate contained 0.02 parasite genome copies. 16/243 (6.6%) viable Charollais, 30/263 (11.4%) viable Swaledale, 3/54 non-viable Charollais and 0116 non-viable Swaledale were PCR-positive, showing no difference between flocks. At age four months 64/524 (12.2%) Charollais and 10/329 (3.0%) Swaledale were seropositive, showing relatively high seroprevalence in Charollais. 5/44 non-viable Charollais and 1114 non-viable Swaledale were seropositive. Colostrum ELISA was 75% sensitive and 100% specific relative to serum MAT. 15/408 (3.7%) Charollais and 31139 (2.2%) Swaledale were colostrum ELISA-positive, showing no difference between flocks. PCR positivity was not associated with seropositivity. PCR positivity was randomly dispersed between litters. In Charollais seropositivity was overdispersed between litters, seroprevalence was higher than PCR prevalence, young ewes' lambs were frequently PCR-positive and large litters frequently contained seropositive lambs. Those results might have been due to vertical transmission. In Swaledale, PCR positivity was not associated with ewe age and seropositivity was rare. Those results suggested little transmission. Lamb seroconversion, and colostrum ELISA positivity, were not associated with ewe age. Overall, it is suggested that ewes ingested oocysts but vertical transmission was sometimes interupted by lambing, especially in Swaledale. In eight cases clinical toxoplasmosis was suspected. No evidence was found suggesting subclinical effects of T. gondii leading to reduced lamb survival. Charollais born PCR-positive were relatively light at age two months but that association was not found in Swaledale. Serology did not confirm any stunting effect.
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Roch-Deries, Florance Candolfi Ermanno. "Choriorétinite à toxoplasma gondii." [S.l] : [s.n.], 2003. http://www.scd.uhp-nancy.fr/docnum/SCDMED_T_2003_ROCH_DERIES_FLORENCE.pdf.
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Paugam, André. "Protéasome de "Toxoplasma gondii"." Paris 5, 2002. http://www.theses.fr/2002PA05P611.
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Le protéasome est un complexe protéique cellulaire dont le rôle essentiel est la protéolyse des protéines anormales. Notre objectif était de caractériser le protéasome du toxoplasme (tachyzoi͏̈tes de la souche RH). Par immunoblot, nous avons montré que des extraits cellulaires de toxoplasmes étaient marqués par l'anticorps anti-protéasome MCP231. Par immunofluorescence et microscopie confocale, nous avons observé une localisation essentiellement cytoplasmique du protéasome de T. Gondii, résultat confirmé par la microscopie électronique. L'étude des activités protéolytiques du protéasome a montré que l'activité chymotrypsine-similaire du toxoplasme est proche de celle des cellules de mammifères, alors que l'activité trypsine-similaire est 20 fois plus faible. A l'aide d'un modèle d'infection de fibroblastes murins nous avons étudié l'effet du traitement des toxoplasmes par la gliotoxine, inhibiteur naturel du toxoplasme. L'invasion é été appréciée, 2h après l'infection, par le pourcentage de cellules infectées détectées par cytofluorimétrie de flux (utilisation d'une souche de toxoplasme RH mutée pour exprimer la protéine fluorescente GFP). La multiplication intracellulaire a été quantifiée par le pourcentage d'incorporation d'uracile tritié de cultures de 24h. Bien que la gliotoxine ne modifie pas la pénétration dans les cellules hôtes, elle diminue fortement la multiplication intracellulaire des parasites (CI50 de 0,5m[mu grec]M). L'effet inhibiteur de la gliotoxine sur l'activité chymotrypsine-similaire est 5 fois plus faible pour les toxoplasmes que pour les cellules HeLa. Pour caractériser la structure du protéasome du toxoplasme, nous avons étudié ses sous-unités par électrophorèse bi-dimensionnelle. La comparaison des profils des sous-unités colorés au nitrate d'argent du protéasome de toxoplasme avec le protéasome humain (placenta) a montré des profils différents. L'immunomarquage (anticorps antiprotéasome) montre qu'au moins une des différences protéiques observées concerne bien le protéasome. La caractérisation de cette sous-unité par spectrométrie de masse est en cours d'étude. La caractérisation du protéasome de toxoplasme et sa comparaison avec celui de la cellule hôte, en mettant en évidence des différences significatives, pourrait ouvrir la voie à de nouvelles perspectives thérapeutiques.
10
Xia, Dong. "Proteomics of Toxoplasma gondii." Thesis, University of Liverpool, 2009. http://livrepository.liverpool.ac.uk/1276/.
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The Apicomplexan parasite Toxoplasma gondii is an obligate intracellular parasite. Infection by T .gondii causes the disease toxoplasmosis, which is one of the most prevalent parasitic diseases of animals and humans. It has been 100 years since the first discovery of the parasite in 1908; research on T. gondii has been carried out in many scientific disciplines consistently expanding the understanding of this parasite. In the last ten years, the developments of EST, microarray, genome sequencing and continuing efforts towards genome annotation has centralized the focus of T. gondii research on the understanding of gene expression and gene functions on the genome scale. Equipped with the technical advances in mass spectrometry and bioinformatics, proteomics has become established as an integral component in the post-genomics era by providing first-hand data on the functional products of gene expression. In this study, three complementary proteomic strategies, 1-DE, 2-DE and MudPIT, have been used to characterise the proteome of T. gondii tachyzoites. Protein identifications have been acquired for more than two thousand (2252) unique release 4 genes, representing almost one third (29%) of the predicted proteome of all life cycle stages. Functional predictions for each protein were carried out, which provided valuable insights into the composition of the expressed proteome and their potential biological roles. The T. gondii proteomic data has been integrated into the publically accessible ToxoDB, where 2477 intron-spanning peptides provided supporting evidence for correct splice site annotation of the release 4 genome annotation. The incompleteness of the release 4 genome annotation has been highlighted using peptide evidence, confirming 421 splice sites that are only predicted by alternative gene models. Analysis has also been carried out on the proteomic data in the light of other genome wide expression data. The comparison of the proteome and transcriptome of Toxoplasma and other Apicomplexa parasites has revealed important discrepancies between protein and mRNA expression where interesting candidates have been highlighted for further investigation. A preliminary DIGE study has been developed to characterize protein expression changes in T. gondii grown in the presence or absence of glucose. In conclusion, this study has demonstrated the importance of proteomic applications in understanding gene expression profiles and regulation in T. gondii and highlighted the importance and potential of proteogenomic approaches in genome annotation process. The importance of temporal and quantitative proteomics as well as the future of systems biology has been discussed.
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Carlon, Nicole. "Les facteurs génétiques et hormonaux de la différenciation des gonades chez les vertébrés supérieurs : morphogenèse de la gonade et action des stéroïdes in vitro chez l'embryon de poulet." Aix-Marseille 2, 1986. http://www.theses.fr/1986AIX21901.
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com, Nevi Parameswaran@gmail, and Nivethitha (Nevi) Parameswaran. "Toxoplasma gondii in Australian Marsupials." Murdoch University, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100203.145857.
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Diagnostic tools were developed and utilised to detect Toxoplasma gondii infection in a range of Australian marsupial species and identify epidemiological trends. An ELISA was developed to detect anti-T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA was in high agreement and yielded a ê coefficient of 0.96. Of 18 western grey kangaroos (Macropus fuliginosus) tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating that the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay.
A T. gondii seroprevalence study was undertaken on free ranging Australian marsupials. There was a T. gondii seroprevalence of 15.5% (95%CI: 10.7-20.3) in western grey kangaroos located in the Perth metropolitan area. The T. gondii seroprevalence in male western grey kangaroos was significantly less than their female counterparts (p=0.038), which may be related to behavioural differences causing differences in exposure to oocysts or recrudescence of T. gondii infection in pregnant females. Marsupial populations located in islands free from felids had a low overall T. gondii seroprevalence. A case control study determined that marsupials located in areas where felids may roam are 14.20 (95%CI: 1.94-103.66) times more likely to be T. gondii seropositive than marsupials located on felid-free islands.
PCR, immunohistochemistry and serological techniques were used to detect T. gondii infection in marsupial dams and their offspring. T. gondii DNA was detected in the pouch young of chronically infected western grey kangaroos and a woylie (Bettongia penicillata). T. gondii DNA was also identified in the mammary gland of the woylie dam suggesting that infection of the woylie pouch young was from suckling milk from the mammary gland. Results of the study demonstrate that vertical transmission of T. gondii occurs in Australian marsupials and may be of importance in the maintenance of T. gondii infection in Australian marsupial populations.
Animal tissue and meat from Australia, predominately from Australian marsupials, were screened for T. gondii DNA using PCR primers for the multi-copy, T. gondii specific B1 gene. Sequencing of the B1 gene revealed atypical genotypes in 7 out of 13 samples from Australia. These 7 isolates contained single nucleotide polymorphisms (SNPs) in the B1 gene that could not be matched with known sequences from strains I, II, III and X. Six unique genotypes were identified out of the 7 atypical isolates; two out of the 7 isolates had the same unique sequence at the B1 gene whereas the other 5 isolates each had different combinations of SNPs at the B1 gene. A majority of T. gondii isolates sampled from native Australian marsupials were of an atypical genotype. The discovery of atypical strains of T. gondii in Australia leads to further questions regarding the origin and transmission of these atypical strains. Additional studies linking atypical strains with their clinical manifestation are also warranted.
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Parameswaran, Nivethitha (Nevi). "Toxoplasma gondii in Australian Marsupials." Parameswaran, Nivethitha (Nevi) (2008) Toxoplasma gondii in Australian Marsupials. PhD thesis, Murdoch University, 2008. http://researchrepository.murdoch.edu.au/1680/.
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Diagnostic tools were developed and utilised to detect Toxoplasma gondii infection in a range of Australian marsupial species and identify epidemiological trends. An ELISA was developed to detect anti-T. gondii IgG in macropod marsupials. When compared with the commercially available MAT (modified agglutination test), the ELISA was in high agreement and yielded a ê coefficient of 0.96. Of 18 western grey kangaroos (Macropus fuliginosus) tested for the presence of T. gondii DNA by PCR, the 9 ELISA positive kangaroos tested PCR positive and the 9 ELISA negative kangaroos tested PCR negative indicating that the ELISA protocol was both highly specific and sensitive and correlated 100% with the more labour intensive PCR assay.
A T. gondii seroprevalence study was undertaken on free ranging Australian marsupials. There was a T. gondii seroprevalence of 15.5% (95%CI: 10.7-20.3) in western grey kangaroos located in the Perth metropolitan area. The T. gondii seroprevalence in male western grey kangaroos was significantly less than their female counterparts (p=0.038), which may be related to behavioural differences causing differences in exposure to oocysts or recrudescence of T. gondii infection in pregnant females. Marsupial populations located in islands free from felids had a low overall T. gondii seroprevalence. A case control study determined that marsupials located in areas where felids may roam are 14.20 (95%CI: 1.94-103.66) times more likely to be T. gondii seropositive than marsupials located on felid-free islands.
PCR, immunohistochemistry and serological techniques were used to detect T. gondii infection in marsupial dams and their offspring. T. gondii DNA was detected in the pouch young of chronically infected western grey kangaroos and a woylie (Bettongia penicillata). T. gondii DNA was also identified in the mammary gland of the woylie dam suggesting that infection of the woylie pouch young was from suckling milk from the mammary gland. Results of the study demonstrate that vertical transmission of T. gondii occurs in Australian marsupials and may be of importance in the maintenance of T. gondii infection in Australian marsupial populations.
Animal tissue and meat from Australia, predominately from Australian marsupials, were screened for T. gondii DNA using PCR primers for the multi-copy, T. gondii specific B1 gene. Sequencing of the B1 gene revealed atypical genotypes in 7 out of 13 samples from Australia. These 7 isolates contained single nucleotide polymorphisms (SNPs) in the B1 gene that could not be matched with known sequences from strains I, II, III and X. Six unique genotypes were identified out of the 7 atypical isolates; two out of the 7 isolates had the same unique sequence at the B1 gene whereas the other 5 isolates each had different combinations of SNPs at the B1 gene. A majority of T. gondii isolates sampled from native Australian marsupials were of an atypical genotype. The discovery of atypical strains of T. gondii in Australia leads to further questions regarding the origin and transmission of these atypical strains. Additional studies linking atypical strains with their clinical manifestation are also warranted.
14
Kremer, Katrin. "Vesicular trafficking in Toxoplasma gondii." Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4753/.
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Toxoplasma gondii is an obligate intracellular protozoan parasite with a worldwide prevalence. Together with the causative agent of malaria (Plasmodium falciparum) and other medically important pathogenic parasites it belongs to the phylum of the Apicomplexa. Besides identifiable eukaryotic organelles, apicomplexan parasites differ from other eukaryotic cells by an extra set of specialised secretory organelles (micronemes, rhoptries and dense granules), that are sequentially secreted during invasion of the host cell. Upon host cell contact the apically located micronemes are the first organelles to be released and contain crucial virulence factors that are secreted. In order to systematically analyse vesicular traffic with a special focus on the secretory pathway of rhoptry and microneme proteins the ddFKBP system was used to perform a systematic analysis of Rab proteins in Toxoplasma gondii. Rab proteins are small GTP- binding proteins that are involved in targeting and fusion of vesicles from a donor to an acceptor membrane. Whereas higher eukaryotes like human cells encode more than 60 different Rab proteins apicomplexan parasites possess only a reduced core set of Rab proteins. Performing co-localisation studies with generated parasite lines expressing ddFKBPmyc-tagged versions of Rab1A, 1B, 2, 4, 5A, 5C, 7, 18 and Rab5B-ddFKBPHA revealed, that all these Rabs localise to the early secretory pathway (Rab1B, 2 and 18), the Golgi (Rab4), or the late secretory pathway (Rab5A, Rab5B, Rab5C and Rab7). No exact localisation could be defined for Rab1A. Rab5A and Rab5C, normally involved in endocytic uptake, were identified as important regulators of traffic to micronemes and rhoptries in Toxoplasma gondii, using an overexpression screen of Rabs and the analysis of trans-dominant mutants of promising candidates. Intriguingly, some microneme proteins could be found to traffic independently on functional Rab5A and Rab5C, indicating the existence of independent transport routes to micronemes, which again indicates that apicomplexans have remodelled Rab5-mediated vesicular traffic into a secretory system that is essential for host cell invasion. By using two-colour super-resolution stimulated emission depletion (STED) microscopy, distinct localisations of independent microneme proteins could be verified. This demonstrated that micronemal organelles are organised in distinct subsets or subcompartments. Given these results, it can be assumed that apicomplexan parasites modify classic regulators of the endocytic system to carry out essential parasite-specific roles in the biogenesis of their unique secretory organelles.
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Bhalla, Mayank. "Molecular studies on Toxoplasma gondii." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339977.
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Parameswaran, Nevi. "Toxoplasma gondii in Australian marsupials /." Murdoch University Digital Theses Program, 2008. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20100203.145857.
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Gonser, Monika [Verfasser]. "Betriebliche Arbeitsbeziehungen in Estland, Lettland und Litauen : Rahmenbedingungen und Praxis / Monika Gonser." Baden-Baden : Nomos Verlagsgesellschaft mbH & Co. KG, 2013. http://d-nb.info/1108816517/34.
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Woods, Stuart. "Immunological control of toxoplasma gondii infection." Thesis, University of Strathclyde, 2012. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=19276.
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Prevalent worldwide, the protozoan parasite, Toxoplasma gondii, is an important cause of spontaneous abortion, ocular disease, mental retardation and encephalitis. Currently there are no human vaccines available. The first major aim of this study was to test potential HLA restricted peptide vaccines, previously shown to be protective in HLA-transgenic mice, against oocyst infection. The ability of entrapment within non-ionic surfactant vesicles to improve the efficacy of the HLA-B*0702 restricted vaccine was also studied. In parallel we tested the novel T. gondii ΔRPS13 live-attenuated vaccine against oocyst challenge. As determined by survival, only ΔRPS13 provided a measure of protection against oocyst challenge. We also demonstrated that the live vaccine induced a greater CD8+ T cell effector response than the adjuvanted peptide vaccine. Successful vaccination is in large part dependent on inducing an appropriate response in the primary host cell populations that consequently influences the development of adaptive immunity. Parasite induced macrophage arginase-1 expression, for example, has been shown to be influential during T. gondii infection. Arginase-1 expression is negatively regulated by Map Kinase Phosphatase-2 (MKP-2), the second major aim of the project was to study the effect of MKP-2 deficiency on T. gondii infection. MKP-2-/- mice were found to be more susceptible to infection with increased parasite growth and increased mortality compared with wild type mice. Increased susceptibility was associated with reduced serum nitrite levels and enhanced tissue arginase-1 expression although the Th1 response was unaltered. In vivo inhibition of iNOS and arginase-1 revealed that while NO production is of paramount importance in controlling parasite growth arginase-1 could also limit parasite growth independently. In vitro studies utilising macrophages confirmed a role for arginase-1 in parasite control. Results highlight a complex interaction between iNOS and arginase-1 and T. gondii in L-arginine metabolism but indicate that manipulation of early infection events influence disease outcome.
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Roberts, Craig William. "Immunological control of Toxoplama gondii infection." Thesis, University of Strathclyde, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389701.
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Ravindran, Sandeep. "Effector protein secretion by toxoplasma gondii /." May be available electronically:, 2009. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Cirelli, Kimberly M. "Rodent inflammasome activation by Toxoplasma gondii." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105635.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Biology, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references.
Toxoplasma gondii is an obligate intracellular pathogen capable of chronically infecting nearly all warm-blooded animals, including humans. The chronic stage is characterized by the presence of semi-dormant cysts in brain and muscle tissues. These cysts are crucial in the success of Toxoplasma as they are orally infectious and allow for the transmission of the parasite between hosts. As the host immune response drives cyst formation, the establishment of this chronic infection relies on the parasite's ability to find a balance between activation of a host immune response and evasion of parasiticidal mechanisms. This balance is achieved through the modulation of host cell processes by parasite proteins secreted from specialized secretory organelles known as rhoptries and dense granules. Here, we report that Toxoplasma activates the inflammasomes in mice and rats. The inflammasomes are a set of cytoplasmic pattern recognition receptors (PRRs). Activation of the inflammasomes results in caspase-1 activation and the cleavage and release of the pro-inflammatory cytokines, Interleukin (IL)-1[beta] and IL-18. IL-1p is an important mediator of local inflammation and neutrophil recruitment. IL- 18 induces Interferon (IFN)-[gamma], which is a critical cytokine in the control of Toxoplasma. A form of cell death, termed pyroptosis, can accompany inflammasome activation. The NLRP3 inflammasome is activated in mouse macrophages, leading to the secretion of IL-1[beta] in vitro. The NLRP1 and NLRP3 inflammasomes play a major role in mouse survival and control of parasite replication in vivo. The NLRPI inflammasome is activated in infected macrophages from rats that are able to completely clear infection. Toxoplasma infection leads to the secretion of active IL-I[beta] and IL-18. Activation of the NLRP1 inflammasome leads to pyroptosis, a programmed form of cell death. Pyroptosis prevents parasite replication within the host cell and likely promotes clearance by nearby immune cells. Using a chemical mutagenesis screen, we identified three Toxoplasma dense granule proteins (GRAs), GRA18, GRA27 and GRA28, essential for NLRP1 inflammasome activation and pyroptosis in rat macrophages. Our work has identified Toxoplasma gondii as a novel activator of the rodent inflammasomes and demonstrated host cell death as a mechanism to control parasite replication. We have also identified three novel parasite proteins required for this activation, providing insight into interactions between parasite and host, which may aid in the treatment of human infection.
by Kimberly M. Cirelli.
Ph. D.
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Chaichan, Patcharee. "Epidemiology of Toxoplasma gondii in Thailand." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0014/document.
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Toxoplasma gondii est un parasite intracellulaire obligatoire. L'infection par T. gondii est largement répandue dans le monde entier. Néanmoins, elle est peu étudiée dans les pays d'Asie du Sud-est dont la Thaïlande.Nous avons réalisé 3 travaux sur le terrain en Thaïlande pour essayer de comprendre la circulation de ce parasite à travers une étude de séroprévalence chez des poulets en zone rurale et des essais d’isolement de souches chez les animaux en vue d’un génotypage. Lors des deux premières missions de terrain dans deux villages de la province de Kanchanaburi, nous avons cherché à déterminer la séroprévalence de l’infection chez des poulets (Gallus domesticus) en utilisant 2 tests sérologiques, Modified-Agglutination Test (MAT et immunofluorescence indirecte (IFAT) puis à isoler des souches de T.gondii à partir des animaux séropositifs. Lors de la troisième mission réalisée dans 3 autres provinces thaïlandaises(Nakhonratchasima, Lopburi et Saraburi), nous avons essayé d’isoler directement le parasite à partir de carcasses de poulets vendues sur les marchés ou d’autres animaux trouvés morts.La séroprévalence globale pour les 2 premières misions sur 600 poulets du Kanchanaburi était de 17,7% (IC 95% :14,6-20,7) et 33,0% (IC 95% : 29,2-36,8), par MAT et IFAT respectivement. Le calcul du coefficient κ montre une absence de concordance entre les deux tests.Au total, 162 essais d'isolement ont été effectués par inoculation à des souris, mais aucune souche viable de T. gondii n'a été isolée pendant ces 3 travaux sur le terrain. Cependant, nous avons détecté la présence d’ADN toxoplasmique en qPCR ciblant le gène 529 bp dans 13 culots de digestion d’organes de poulets, pigeon, caille et dans des cerveaux ou coeurs de souris inoculés par 16 autres poulets. Les Ct observés en qPCR étaient ≥33 indiquant une faible quantité d’ADN parasitaire dans nos échantillons qui n’a pas permis une caractérisation génétique par marqueurs microsatellites.Ce travail a démontré l'importance et les difficultés du travail de terrain pour l'étude de séroprévalence ainsi que l'étude d'isolement. L'isolement des souches de T. gondii a demandé un travail d'échantillonnage intensif, complexe dans l’environnement tropical et humide de la Thaïlande. Les différents paramètres ayant pu avoir un impact négatif sur nos résultats sont discutés. Ils expliquent l’absence d’isolement de souches chez des animaux séropositifsToxoplasma gondii is an obligate intracellular parasite. Toxoplasma gondii infection is widespread throughout the world. Nevertheless, it is poorly studied in Southeast Asian countries including Thailand. We carried out 3 field works in Thailand to try to understand the circulation of T. gondii through a seroprevalence study in chickens in rural areas and strain isolation attempts in animals. During the two first field works, performed in Kanchanaburi province, we determined the seroprevalence in chickens (Gallus domesticus) using 2 serological tests, a Modified-Agglutination-Test (MAT) and an immunofluorescence assay (IFAT) and subsequently tried to isolate the strains of T. gondii from seropositive animals. During the third field work carried out in 3 other Thai provinces (Nakhonratchasima,Lopburi and Saraburi), we attempted to isolate strains directly from chicken carcasses sold in different markets or other dead animals.The overall seroprevalence for 600 chickens sampled over the two field works in Kanchanaburi was 17.7% (95%CI: 14.6% -20.7) and 33.0% (95% CI: 29.2-36.8), by MAT, and IFAT, respectively. The κ coefficient indicated an absence of concordance between the 2 serological tests.A total of 162 isolation attempts were performed by mouse bioassays, but no viable strain of T. gondii was isolated during these 3 field works. However, a qPCR targeting 529 bp T. gondii gene was positive for 13 digestion pellets of organs of chickens, pigeon, quail and in brains or hearts of mice inoculated with 16 other chickens. These qPCR were weaklly positive (Ct ≥33) indicating a low amount of parasite DNA in our samples that did not allow genotyping T. gondii with microsatellite markers.This work demonstrated the importance and difficulties of field work for the seroprevalence study as well as strain isolation. The isolation of T. gondii strains required intensive and complex sampling in the tropical and humid environment of Thailand. The diverse factors that could have a negative impact on our results are discussed. They might explain the absence of strain isolation from seropositive animals
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Gonser, Phillipp [Verfasser], and Ulrich [Akademischer Betreuer] Matern. "Kosten-Nutzen Analyse von Gebrauchstauglichkeitstests in der Medizin / Phillipp Gonser ; Betreuer: Ulrich Matern." Tübingen : Universitätsbibliothek Tübingen, 2011. http://d-nb.info/1161734562/34.
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Busi, Simone <1972>. "Gondor e Zarado: valutazione degli effetti di nuovi coadiuvanti antideriva sull'attività degli erbicidi." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2047/.
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L’irrigidimento del contesto regolamentare europeo dovuto all’attuale condizione di contaminazione diffusa dell’ambiente, riscontrata in Italia e in molti altri paesi europei, ha visto l’esigenza sempre più pressante di razionalizzare le dosi dei fitofarmaci utilizzati in agricoltura. Lo sviluppo e l’utilizzo di nuovi prodotti coadiuvanti come specifici antideriva per erbicidi, rappresenta in questo senso, un’importante risorsa su cui si
inizia a fare affidamento. In Francia, per esempio, già da alcuni anni ci sono normative che obbligano l’utilizzo in agricoltura di tali prodotti, mentre in Italia non si hanno ancora direttive precise a riguardo. In tal contesto l’obiettivo principale di questa ricerca, effettuata in
collaborazione con la ditta Intrachem, è stato quello di studiare alcune caratteristiche funzionali relative a due prodotti, che verranno lanciati a breve sul mercato, come specifici antideriva per erbicidi. In particolar modo è stato fatto uno studio per verificare se ed eventualmente come, questi coadiuvanti (Gondor e Zarado) possono influenzare l’attività del principio attivo a cui vengono aggiunti, apportando variazioni relative alla sua efficacia.
Lo schema di lavoro seguito ha previsto una prima fase di saggio dove venivano effettuati test dose-risposta, utilizzando diversi erbicidi a diverse concentrazioni. I test sono stati effettuati su alcune malerbe mono e dicotiledoni. In ciascuna di queste prove è stata valutata e
confrontata la percentuale di sopravvivenza e il peso dei sopravvissuti tra le tesi trattate. Le tesi prevedevano trattamenti con erbicida e trattamenti con erbicida più uno dei due coadiuvanti. Nella seconda fase si è effettuato un approfondimento sulle tesi che hanno mostrato i risultati
più interessanti, per capirne possibilmente le basi fisiologiche. In particolare si è verificato se l’aggiunta dei due antideriva potesse determinare cambiamenti durante la fase di assorbimento e di traslocazione del principio attivo all’interno della piantina, utilizzando molecole radiomarcate con C14. Dai risultati ottenuti si è potuto
evidenziare come l’aggiunta dei coadiuvanti possa rendere più efficace l’azione dell’erbicida nei casi in cui le infestanti non vengono completamente controllate dagli stessi (stadio vegetativo troppo avanzato e resistenza all’erbicida). Non è stato sempre verificato che ad un miglioramento dell’efficacia coincida un aumento dell’assorbimento e della traslocazione del principio attivo, all’interno della pianta. In conclusione si è potuto constatare che Gondor e Zarado oltre a svolgere la loro funzione antideriva, non influenzano negativamente
l’efficacia dell’erbicida, salvo poche eccezioni, ma al contrario possono potenziarne l’azione, nelle situazioni “border line”.
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Parigi, Maria <1984>. "Toxoplasma gondii in animals and the environment." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6423/.
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Toxoplasma gondii is an obligate intracellular parasite capable of infecting virtually all warm-blooded species, including humans, but cats are the only definitive hosts. Humans or animals acquire T. gondii infection by ingesting food or water contaminated with sporulated oocysts or by ingesting tissue cysts containing bradyzoites. Toxoplasmosis has the highest human incidence among zoonotic parasitic diseases, but it is still considered an underreported zoonosis. The importance of T. gondii primary infection in livestock is related to the ability of the parasite to produce tissue cysts in infected animals, which may represent important sources of infection for humans.
Consumption of undercooked mutton and pork are considered important sources of human Toxoplasma gondii. The first aim of this thesis was to develop a rapid and sensitive in- house indirect ELISA for the detection of antibodies against T. gondii in sheep sera. ROC-curve analysis showed high discriminatory power (AUC=0.999) and high sensitivity (99.4%) and specificity (99.8%) of the method. The ELISA was used to test a batch of sheep sera (375) collected in the Forli-Cesena district. The overall prevalence was estimated at 41.9% demonstrating that T. gondii infection is widely distributed in sheep reared in Forli-Cesena district.
Since the epidemiological impact of waterborne transmission route of T.gondii to humans is now thought to be more significant than previously believed, the second aim of the thesis was to evaluate PCR based methods for detecting T. gondii DNA in raw and finished drinking water samples collected in Scotland. Samples were tested using a quantitative PCR on 529 bp repetitive elements. Only one raw water sample (0.3%), out of the 358 examined, tested T. gondii positive demonstrating that there is no evidence that tap water is a source of Toxoplasma infection in Scotland.
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Bertin, Brigitte. "Etude immunochimique des antigènes de Toxoplasma gondii." Grenoble : ANRT, 1985. http://catalogue.bnf.fr/ark:/12148/cb37594507t.
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Hartmann, Jan. "Golgi and centrosome cycles in Toxoplasma gondii." [S.l. : s.n.], 2005.
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Oliveira, Natalia Nepomuceno de. "Caracterização funcional de cepas de T. gondii." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/42/42133/tde-07102009-163451/.
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Mais de 2 bilhões de pessoas em todo o mundo encontram-se infectadas com Toxoplasma gondii. Na região endêmica de Erechim, RS, cerca de 90% da população é soropositiva e cerca de 18% destes indivíduos apresentam lesões oculares com manifestações clínicas. A estrutura genética das populações do T. gondii tem sido bastante investigada, a despeito da infecção ter se espalhado pelo mundo, do grande número de hospedeiros intermediários e da capacidade do parasita de se reproduzir sexualmente. Linhagens de T. gondii com atípica ou nova combinação de alelos têm sido isoladas de animais não domésticos ou em outros continentes, como América do Sul e África, e de pacientes com apresentações clínicas incomuns. Em modelos murinos, as linhagens com o genótipo tipo I são altamente virulentas, em contraste às cepas tipo II e tipo III que são menos virulentas. Este trabalho propõe a caracterização fenotípica da resposta imune do hospedeiro frente a infecção por diferentes cepas de T. gondii, bem como o isolamento e a caracterização genotípica das linhagens de T. gondii que infectam indivíduos de Erechim no Rio Grande do Sul. Para a caracterização fenotípica utilizamos duas cepas de T. gondii já bem estabelecidas, a cepa RH (tipo I) e a ME49 (tipo II), e uma cepa isolada a partir de gatos domésticos do Brasil, chamada TgCatBr71. Sendo assim, através da fenotipagem das células dendríticas de camundongos C57Bl/6 infectados com as cepas citadas, foi possível observar que essas cepas induzem expressão das moléculas de superfície CD40, CD80, CD86 e MHC classe II em DCs CD11c+, porém sem significativa diferença entre as cepas. Com relação as células CD4+ e células CD8+, observamos o aumento das células CD8+ no decorrer da infecção pelas cepas RH e ME49, indicando a importância deste tipo celular na resposta protetora contra T. gondii. Avaliamos também a produção de citocinas IL-12, IFN-g e IL-10 em células esplênicas de camundongos infectados pelas três cepas no decorrer da infecção e detectamos que camundongos infectados pela cepa tipo II (ME49) apresentam síntese maior dessas citocinas do que camundongos infectados pela cepa tipo I (RH) e pela cepa TgCatBr71. Assim, concluímos que esta cepa TgCatBr71 se assemelha bastante a cepa do tipo I (RH), tanto em relação a evolução da doença no camundongos como nos padrões da resposta imune do hospedeiro. E que apesar dessas duas cepas diferirem da cepa tipo II (ME49), resultando em graus diferentes de patologia em camundongos C57Bl/6, todas a três cepas parecem produzir semelhante resposta imune protetora do hospedeiro.More than 2 billion people are infected with Toxoplasma gondii around the world. In the endemic region of Erechim, RS, Brazil, about 90% of the population is soropositive and about 18% of these individuals have ocular lesions with clinical manifestations. The genetic structure of strains of T. gondii has been investigated, despite the infection has spread throughout the world, the large number of intermediate hosts and the ability to reproduce sexually. Strains of T. gondii with atypical or new combination of alleles have been isolated from wild animals and other continents, such as South America and Africa, and also from patients with unusual clinical presentations. In murine models, the type I genetic lineage are highly virulent, in contrast to strains type II and type III.Our work proposes the phenotypic characterization of the host immune response against the infection by different strains of T. gondii, and the isolation and genetic strains characterization of T. gondii that infect individuals of Erechim in RS, Brazil. In the phenotypic characterization were used two strains of T. gondii already well established, the strain RH (type I) and ME49 (type II), and a strain isolated from domestic cats from Brazil, called TgCatBr71 (type BrI). Thus, by phenotyping dendritic cells of C57BL/ 6 mice infected with the strains mentioned, we observed that these strains upregulated the expression of surface molecules such as CD40, CD80, CD86 and MHC class II in DC CD11c+ although with no significant difference between the strains. With respect to the CD4+ and CD8+ cells, the observed increase in CD8+ T cells during the infection by strains RH and ME49, indicating the importance of this cell type in the protective response against T. gondii. We also evaluated the production of cytokines IL-12, IFN-g and IL-10 from spleen cells and found that mice infected by the strain type II (ME49) have increased synthesis of these cytokines than mice infected by the strain type I (RH) and the strain type BrI (TgCatBr71). Thus, we concluded that type BrI (TgCatBr71) strain is similar to type I (RH) strain, both for the evolution of the disease and also concerning the immunological parameters evaluated. Besides, despite these two strains differ from the strain type II (ME49), resulting in different degrees of pathology in mice C57BL / 6, all three strains seem to produce similar protective immune response of the host.
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Jesus, Rogerio Fernando de. "Infeccção natural por Toxoplasma gondii em quirópteros." Universidade Federal da Bahia, 2015. http://repositorio.ufba.br/ri/handle/ri/20375.
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CONS NAC DE DESENVOLVIMENTO CIENTIFICO E TECNOLOGICO - CAPES
Toxoplasma gondii é um protozoário coccídeo formador de cistos teciduais, que tem como hospedeiros definitivos os felídeos, e como hospedeiros intermediários mamíferos e aves. É um parasito disseminado em todos os continentes, que infecta aproximadamente um terço da população humana e pode causar encefalite fatal em pacientes imunodeficientes. Nos animais, tem relevância principalmente em pequenos ruminantes, por causar abortos e outras alterações reprodutivas. Quirópteros podem se infectar com T. gondii e atuarem como fonte de infecção para animais silvestres, domésticos e o homem. No Brasil, ocorre uma alta variabilidade genética do parasito, que pode ser explicada pela grande variedade de hospedeiros no ambiente silvestre. Objetivou-se com este estudo determinar a frequência de infecção em quirópteros de vida livre no estado da Bahia por T. gondii e realizar o isolamento in vivo do protozoário a partir desses animais. Foram utilizadas 124 amostras, provenientes de 97 indivíduos de sete espécies de morcegos, capturados entre os anos de 2008 e 2015, sendo encontrados dois indivíduos positivos por meio da PCR de tecidos, correspondendo a 2,06% de positividade. Nenhum isolamento foi realizado uma vez que os tecidos disponíveis para bioensaio apresentaram-se negativos na PCR
Toxoplasma gondii is a cyst-forming protozoan coccidia, which has felids as definitive hosts, and mammals and birds as intermediate hosts. It’s distributed in all continents and infects about a third of the human population. T. gondii can cause fatal encephalitis in immunodeficient patients. In animals, it’s relevant mainly in small ruminants, for causing abortions and other reproductive abnormalities. Bats can become infected with T. gondii and act as a source of infection for wild and domestic animals and man. In Brazil, there is a high genetic variability of the parasite, which can be explained by the great variety of hosts in the wild environment. The objective of this study was to determine the frequency of free-living bats infection in Bahia by T. gondii and perform in vivo isolation of the parasite from these animals. A total of 124 samples were used from 97 individuals of seven species of bats, caught between the years 2008 and 2015. Two animals were positive by tissue PCR, corresponding to 2.06% of positivity. No isolation was achieved once the tissue available for bioassay showed to be negative by PCR.
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Carey, Robert Francis IV. "Toxoplasma gondii and behavioral modification in hosts." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12065.
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Thesis (M.A.)--Boston UniversityToxoplasma gondii is a heteroxenous protozoan parasite that is found in nearly every species of mammal and billions of latently infected humans worldwide. The symptoms and morbidities associated with acute, congenital, and AIDS-associated toxoplasmosis are familiar to many, while those associated with latent toxoplasmosis are not nearly as well known. Behavioral manipulation is a common strategy of parasite and parasitoid species, and recent research into T. gondii has revealed that T. gondii infection alters the way rodents respond to the odor of the urine of its feline predators, which are also the definitive hosts of T. gondii. Humans have been found to be potentially affected by T. gondii as well: associations have been identified between latent T. gondii infection and psychiatric diseases (including schizophrenia), personality changes, and traffic accidents. This review investigates the state of current scientific knowledge related to Toxoplasma gondii, analyzes recent developments, and examines the implications on public health. We also provide critical analysis of the published literature and make suggestions for future research.
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Riahi, Dehkordi Hamayoun. "Hammondia hammondi : études comparatives avec Toxoplasma gondii." Limoges, 1997. http://www.theses.fr/1997LIMO105E.
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Bertin, Brigitte. "Etude immunochimique des antigènes de Toxoplasma gondii." Bordeaux 2, 1985. http://www.theses.fr/1985BOR22001.
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Liu, Elizabeth. "The Autophagy Pathway and Toxoplasma gondii Infection." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1428103561.
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Burrells, Alison Clair. "Toxoplasma gondii in animal and human hosts." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9628.
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The protozoan parasite Toxoplasma gondii (T. gondii) is an important zoonotic pathogen, which has the ability to infect all warm blooded mammals including humans, with approximately one third of the human population predicted to be infected. Transmission of the parasite to the foetus during pregnancy can result in miscarriage, however, a child infected during pregnancy may go on to develop clinical symptoms such as retinochoroiditis (ocular toxoplasmosis), hydrocephalus or learning difficulties in later life. Post-natally acquired infection in humans is generally asymptomatic, however, individuals who are immunocompromised may develop ocular toxoplasmosis or toxoplasmic encephalitis. T. gondii type II is reported to be the predominant genotype in Europe and the United States, but currently very little information exists about the prevalence and genotypes present within Great Britain. Consumption of T. gondii tissue cysts from raw or undercooked meat is a main source of infection for humans, with infected pork being considered a high risk. Currently the “gold standard” for assessing the viability of infective T. gondii tissue cysts is by an in vivo mouse bioassay. However, more recent ethical requirements to reduce, refine or replace experimental animals raises the question as to whether molecular technologies could be incorporated into these studies to reduce mouse numbers. The main aims of this PhD were to: (i) determine the prevalence and genotypes of T. gondii within different wildlife populations and humans in Great Britain; (ii) determine whether vaccination of pigs with a live attenuated strain of T. gondii would reduce the load of viable T. gondii tissue cysts within this species; (iii) study the viability and dissemination of tissue cysts from oocyst and bradyzoite infected pigs and (iv) to compare mouse bioassay with molecular detection of T. gondii DNA from experimentally infected pigs. The main findings of this work show that the prevalence of T. gondii within carnivorous wildlife varied from 6.0% to 44.4% depending on the host species with type II being the predominant lineage identified, however, type III and two alleles for type I were also present. In humans, serological detection of the parasite from a group of Scottish blood donors from Glasgow and Dundee (n=1403) was determined at 13.0%, molecular detection of T. gondii in human brains (n=151) from the Sudden Death Brain Bank show a prevalence of 17.9%. A correlation between increasing age and an increase in the detection of parasite was identified from both study groups. T. gondii strain genotyping using DNA extracted from human brains identified alleles for type I and III, however, no direct link between cause of death and detection of parasite DNA could be made. Live vaccination and subsequent oocyst challenge of pigs showed a significant reduction in the establishment of viable T. gondii tissue cysts. Mouse bioassay clearly demonstrates this result, where 100% of mice that were inoculated with homogenised tissues from vaccinated/challenged pigs survived, compared to the survival of only 51% of mice, which received homogenised tissues from non-vaccinated/oocyst challenged animals. In addition, porcine tissues from pigs challenged with either oocysts or bradyzoites did not show a significant difference in mouse survival following bioassay of these tissues. Challenge with either stage of the parasite (oocysts or bradyzoites) showed a preference to form tissue cysts in brains and highly vascular muscles (tongue, diaphragm, heart or masseter) of pigs. The findings, comparing mouse bioassay with molecular detection of parasite DNA from homogenised porcine tissue (prior to inoculation into mice), showed similar levels of detection. However, mouse bioassay was more sensitive and also provides evidence of parasite viability. In conclusion, this research not only provides current figures for prevalence and genotypes of T. gondii in both wildlife and humans in Great Britain, it also successfully answers the question as to whether live vaccination of pigs with the S48 strain can reduce the tissue cyst burden. These promising results show the potential of a vaccine against T. gondii in producing safer pork for human consumption. Although the mouse bioassay still remains the most sensitive method for the detection and viability assessment of tissue cysts, further research should be carried out in this area, perhaps incorporating a technique such as magnetic capture qPCR, to enable an effective in vitro technique to be developed.
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Dardé, Marie-Laure. "Contribution à la caractérisation de Toxoplasma Gondii : étude isoenzymatique." Limoges, 1990. http://www.theses.fr/1990LIMO101A.
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Gastens, Martin. "Virulenz-assoziierte Proteine von Toxoplasma gondii Identifikation und funktionelle Charakterisierung /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968522270.
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Adjogblé, Koku Zikpi. "Biochemische und funktionelle Charakterisierung eines neuen "Dense-granules"- Proteins von Toxoplasma gondii: GRA9." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971753792.
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Eidell, Keith. "Development of a novel screen to dissect Toxoplasma gondii egress." Thesis, Boston College, 2010. http://hdl.handle.net/2345/1732.
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Thesis advisor: Marc-Jan GubbelsThe Apicomplexa comprise a group of obligate intracellular parasites some of which cause severe diseases in humans with malaria the most notorious representative. Toxoplasma gondii infection is the most widespread apicomplexan infection, which is mostly symptomless in healthy people but is associated with a variety of birth defects upon congenital infection and can become life threatening in immunocompromised patients. In addition, T. gondii has been established as a model for the study of intracellular parasitism by Apicomplexa. The lytic destruction of host cells underlies the pathogenesis of all apicomplexan diseases. The T. gondii lytic cycle involves host cell invasion, several rounds of intracellular replication, and is followed by egress of motile parasites in order to infect neighboring host cells. Egress is an increasingly more appreciated aspect of the lytic cycle for which three physiological triggers have been identified. All three triggers converge on the release of Ca2+ stores within the parasite. Large sections of the signaling pathways and molecular players associated with egress and intracellular calcium release remain unknown. The objective of this thesis was to develop and employ a novel enrichment screening procedure that would efficiently isolate egress mutants in response to pharmaceutically induced egress. The biggest caveat to such a screen is the ability to separate intracellular from extracellular parasites, which is hampered by the stickiness of parasites to host cells as well as their fast reinvasion capacity. This hurdle was overcome by saturating the parasite's surface receptors with the glycan heparin to prevent attachment to the host cell. Simultaneously, the oxidizing agent pyrrolidine dithiocarbamate (PDTC) was applied to specifically kill extracellular parasites. The enrichment power of the screen was assessed by diluting a previously identified temperature-sensitive egress mutant called F-P2 in wild type parasites. The screen's enrichment power was assessed by flow cytometry and a 1000-fold enrichment capacity to a 100% F-P2 population could routinely be achieved. Subsequently the screen was applied to generate mutants with defects in the poorly understood NTPase mediated egress-trigger pathway. Chemical mutagenesis as well as insertional mutagenesis was applied and dithiotreitol (DTT) that artificially creates the reducing environment triggering egress was used to screen mutants. Three chemically induced constitutive egress mutants and one insertional mutant were isolated. As expected, all mutants displayed resistance to DTT induced egress. In addition, cross resistance to two other egress inducers upstream of Ca2+ release was observed, however all mutants egressed upon calcium ionophore treatment. Taken together, the developed enrichment procedure will enable the isolation of constitutive as well as conditional egress mutants. Future cosmid complementation will help to fill in important blanks in the egress mechanisms and will ultimately lead to a better understanding of intracellular parasitism. This gained understanding will potentially lead to therapies to combat the destructive effects of apicomplexan parasites
Thesis (MS) — Boston College, 2010
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Biology
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Mercier, Corinne. "Toxoplasma gondii : caractérisation moléculaire d'un antigène de granules denses (GRA2). Mise en évidence des promoteurs de transcription des gènes codant pour les protéines granulaires GRA1, GRA2, GRA5 et GRA6." Lille 1, 1994. http://www.theses.fr/1994LIL10043.
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Au cours de ce travail, nous avons entrepris la caracterisation moleculaire de la proteine p28 ou gra2 de toxoplasma gondii. L'antigene gra2 est commun aux stades tachyzoite (stade invasif durant lequel le parasite se divise dans une vacuole parasitophore) et bradyzoite (caracterise par l'enkystement des toxoplasmes). Cette molecule stockee dans les granules denses, est secretee apres l'invasion et est detectee en association avec le reseau de tubules membranaires intravacuolaires. Le clonage et le sequencage de clones d'adnc et d'un clone d'adn genomique ont montre que le gene (1,3 kb) codant pour la proteine nommee gra2 est constitue de deux exons separes par un intron de 241 pb. La sequence en acides amines deduite de l'adnc a ete confirmee en partie par 5 sequences peptidiques issues de la proteine native purifiee par hplc. Les 23 acides amines n-terminaux de gra2 possedent les caracteristiques d'une sequence signal. Le domaine central de la chaine polypeptidique pourrait etre arrange sous forme de 2 alpha helices amphipathiques qui pourraient etre les structures responsables de l'association de gra2 aux membranes du reseau intravacuolaire. L'utilisation de peptides recombinants ainsi que de peptides synthetiques dans un systeme d'elisa direct ont permis de montrer que la proteine gra2 contient au moins 3 epitopes b reconnus par les serums humains d'infection chronique et aigue. Un des epitopes, constitue des 15 acides amines c-terminaux, est aussi reconnu par l'anticorps monoclonal de souris tg17-179. Le meme systeme d'expression, applique a la proteine de granules denses gra1, a permis de souligner l'interet diagnostique de ce dernier composant. Afin de mettre en evidence les promoteurs de transcription des genes de granules denses, les regions 5 des genes gra1 (379pb), gra2 (276pb), gra5 (3205pb) et gra6 (265pb) ont ete clonees devant le gene bacterien codant pour la chloramphenicol acetyl transferase bacterienne. Ces regions permettent l'expression d'une activite cat apres transfection transitoire du toxoplasme. L'analyse de mutants de deletion a permis de localiser les regions promotrices des genes gra dans le proche environnement du site de demarrage de la transcription (-107 a -47 pour gra1, -73 a -37 pour gra2, -51 a -13 pour gra5, -85 a -27 pour gra6). L'analyse de la sequence de ces regions promotrices a mis eu evidence la presence d'un motif caat (-76 a -71) en amont du gene gra1 et de 2 motifs repetes et riches en purines (a/tgagacg) en amont des 4 genes. La transfection de constructions hybrides dans lesquelles les regions 5 non traduites des genes gra1 et gra6 ont ete permutees, montre que ces regions participent aussi au controle de l'expression des proteines gra.
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Gendrin, Claire. "Étude de l’adressage des protéines GRAs transmembranaires de Toxoplasma gondii aux granules denses et de leur insertion membranaire post-sécrétoire." Grenoble 1, 2007. http://www.theses.fr/2007GRE10285.
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Parmi les mécanismes de survie intracellulaire connus, l’export de protéines solubles ou transmembranaires visant à modifier différents compartiments de la cellule-hôte est une stratégie employée par de nombreux pathogènes. Chez Toxoplasma gondii, il a été montré que les granules denses (GD) constituent la voie de sécrétion par défaut pour les protéines solubles. Par contre, le tri de protéines transmembranaires vers les GD et leur maintien sous forme soluble avant insertion membranaire post-sécrétoire font appel à des mécanismes originaux qui ont fait l’objet de ces travaux. Chez le Toxoplasme, la protéine de GD GRA5 est adressée à la membrane de la vacuole parasitophore (MVP) après sécrétion. Exprimée en cellules de mammifères, GRA5 est adressée à la membrane plasmique avec une topologie de type I, ce qui démontre la particularité des mécanismes de sécrétion chez T. Gondii. Par une approche basée sur des protéines chimériques présentant des domaines spécifiques de GRA5 et d’une protéine transmembranaire de la membrane plasmique parasitaire (MPP), nous avons pu identifier les déterminants de l’adressage à la MPP versus à la MVP. Nous avons ainsi pu démontrer que le domaine Nt de GRA5 est impliqué dans l’adressage soluble aux GD et est essentiel pour l’insertion membranaire post-sécrétoire dans la MVP. Ces résultats, qui ont été étendus à une autre protéine GRA transmembranaire (GRA6), divergent de l’idée largement répandue selon laquelle les signaux d’adressage des protéines transmembranaires seraient présents dans la queue C-terminale et/ou dépendraient de la longueur du domaine transmembranaire de ces protéinesThe success of many intracellular pathogens relies on the export of both soluble and membrane-bound proteins that are destined to modify various compartments of the host cell. In Toxoplasma gondii, it is well established that the dense granules (DG) constitute the default constitutive pathway for soluble proteins. By contrast, the mechanism by which transmembrane proteins are sorted to the DG and are maintained in a soluble state while adopting a transmembrane topology after secretion is not known. The GRA5 DG protein of T. Gondii is targeted to the parasitophorous vacuole membrane (PVM) after soluble secretion. Expression of GRA5 in mammalian cells revealed that the protein is targeted to the cell surface with a type I topology, providing evidence that soluble trafficking of GRA5 within the parasite is peculiar. By using chimeric proteins containing specific domains of GRA5 and of a parasite plasma membrane (PPM) targeted transmembrane protein, we investigated which are the determinant(s) of PPM versus PVM targeting. We demonstrated that the GRA5 Nt domain is involved in soluble targeting within the DG and is essential for insertion into the PVM. These results, that were extented to another transmembrane GRA protein (GRA6), contrast with the broad acceptance that sorting signals are present within the cytoplasmic tail of membranous proteins and/or depend on the size of their transmembrane domain
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Silva, Aristeu Vieira da [UNESP]. "Avaliação da infecção de ratos Fischer com dua amostras geneticamente distintas de Toxoplasma gondii: cinética de anticorpos, reisolamento em camundongos e reação em cadeia pela polimerase." Universidade Estadual Paulista (UNESP), 2003. http://hdl.handle.net/11449/101495.
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silva_av_dr_botfm_prot.pdf: 636648 bytes, checksum: 53bbd69b49e6f85da36a6c425cb8447c (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Com relação ao desenvolvimento do quadro clínico e a transmissão transplacentária, a toxoplasmose em humanos e ratos é similar, e a infecção em ratos pode servir como um modelo para a enfermidade humana. Foram inoculados, pela via oral, sete grupos de ratos com 105 (Grupo 1), 104 (Grupo 2) e 103 (Grupo 3) bradizoítos de Toxoplasma gondii cepa BTU-2 (altamente virulenta para camundongos), 105 (Grupo 4), 104 (Grupo 5) e 103 (Grupo 6) bradizoítos de T.gondii cepa ME-49 (pouco virulenta para camundongos) e solução salina estéril (Grupo 7 – Controle). Os animais foram observados durante 84 dias, com colheita semanal de sangue para obtenção de soro e realização das provas sorológicas pelos métodos de aglutinação direta (MAD) e imunofluorescência indireta (RIFI) para anticorpos das classes IgG e IgM. Ao final do período os animais foram sacrificados e fragmentos de tecidos colhidos para reisolamento do parasita em camundongos e para detecção de DNA do T.gondii pela reação em cadeia pela polimerase (PCR), utilizando-se oligonucleotídeos dirigidos para a detecção dos genes SAG- 1, B1, rDNA e para uma seqüência repetida não codificadora (REP). Foi realizada a tipagem da cepa BTU-2 pela avaliação do polimorfismo do gene SAG-2. Todos os ratos desenvolveram títulos de anticorpos detectáveis pelas diferentes técnicas, havendo, independente da cepa inoculada, diferenças mais frequentes entre os grupos que receberam 105 e 103 bradizoítos. Para IgM a partir do 35o DPI e para a RIFI-IgG e o MAD, a cepa BTU-2 induziu títulos mais elevados que a cepa ME-49. A cepa BTU-2 foi isolada de todas as amostras de cérebro e musculatura estudadas, independente da dose utilizada na infecção dos animais, enquanto que para a cepa ME-49, o parasita foi isolado mais frequentemente do cérebro do que da musculatura, com influência da dose infectante...
Referring to the symptoms and transplacentary transmission, toxoplasmosis in humans and rats is similar and rats can be used as a model for the disease in humans. 7 groups of rats were inoculated, by oral administration, using 105 (Group 1), 104 (Group 2) and 103 (Group 3) Toxoplasma gondii bradyzoits from strain BTU-2, which is highly infective to mice and with 105 (Group 4), 104 (group 5) and 103 (Group 6) T.gondii bradyzoits of strain ME-49, which is less infective to mice and, finally, sterile saline solution (Group 7) as a control one. The animals were observed during 84 days, with weekly blood samples, in order to obtain serum and then submitted to serological tests by modified agglutination test (MAT) and imunofluorecent antibody test (IFAT) to antibodies from subtypes IgG and IgM. At the end of time of observation, the animals were killed and samples of their tissues were obtained in order to reisolate the parasite and to detect the T.gondii DNA by polymerase chain reaction (PCR), using specific oligonucleotids to detect the genes SAG-1, B1, rDNA and to no coding repetitive sequence (REP). The BTU-2 strain was classified by the SAG-2 gene polymorphism. All the rats developed detectable antibodies titers, no matter which strain was used between the techniques. The most frequent differences in the serological results were among the groups that received 105 and those who received 103 bradizoits, no matter the strain used. The BTU-2 strain induced higher titles to IgM since 35 DPI and to IFAT-IgG and MAT than the ME-49 strain. The BTU-2 strain also was isolated from all the brain and muscles samples, no matter the dosage used to infect the animals. When the ME- 49 strain was used, the parasite was isolated more frequently... (Complete abstract, click electronic access below)
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Ghiglieri, Carole. "Les TGF-β au cours de la maturation de la gonade." Lyon 1, 1995. http://www.theses.fr/1995LYO1T131.
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Lohr, Michaela. "Vorkommen von Galektinen in den Gonaden der Maus." Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-33289.
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Reitemeier, Susanne. "Morphologische und immunzytochemische Charakterisierung der Gonaden männlicher Papageienvögel." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-133392.
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Gefährdete Spezies in Menschenobhut zu reproduzieren und zu erhalten soll dem weltweiten Rückgang zahlreicher Papageienarten entgegenwirken. Der Erfolg solcher Zuchtprogramme wird unter anderem durch begrenzte Kenntnisse über physiologische und pathologische Vorgänge im Fortpflanzungssystem dieser Vogelordnung erschwert.
Ziel der vorliegenden Arbeit war die Etablierung aussagekräftiger Parameter zur Einordnung des Reproduktionsstatus von männlichen Papageienvögeln. Dabei wurde ein Probenumfang fixierter, männlicher Reproduktionsorgane acht verschiedener Gattungen mit standardisierten histologischen und immunzytochemischen Methoden untersucht. Im Vordergrund stand die morphologische Beurteilung der untersuchten Gonaden im Bezug auf Fortpflanzungsaktivität und -status. Gleichzeitig sollten die immunzytochemischen Analysen Aufschluss über die beteiligten Hormone und Enzyme geben. Für die Etablierung vogel-spezifischer Marker wurde als Vertreter der Psittaciformes der Wellensittich (Melopsittacus undulatus, n=45) als Modellspezies ausgewählt. 15 verschiedene Antikörper aus der Gruppe der Steroidrezeptoren, steroidogenen Enzyme, Relaxinpeptide und Proliferationsmarker wurden an dieser Art getestet. Anschließend erfolgte der Transfer der erarbeiteten Methodik auf sieben weitere Papageiengattungen (Nymphicus, Eolophus, Cacatua, Psittacus, Amazona, Ara, Cyanopsitta).
Anhand der Histologie konnten alle untersuchten Gonaden den drei verschiedenen Reproduktionsstadien aktiv, intermediär und inaktiv zugeordnet werden. Hierbei wurden Kriterien wie die Ausdehnung von Samenkanälchen und Interstitium, Morphologie des Keimepithels, Vorhandensein von Lipofuszin in den Samenkanälchen sowie die Teilungsaktivität von Keimzellen herangezogen. Aktive Hoden zeigen ausgedehnte Tubuli und ein schmales Interstitium, ein Keimepithel mit allen Keimzellstadien, wenig Lipofuszin und eine hohe Teilungsaktivität bei den Keimzellen. Inaktive Hoden hingegen besitzen schmale Tubuli und ein breites Interstitium, ein Keimepithel bestehend aus Sertoli-Zellen und Spermatogonien, Massen an Lipofuszin im Lumen der Samenkanälchen und eine geringe Proliferationsrate der Keimzellen.
14 der 15 getesteten Marker konnten mittels Immunzytochemie erfolgreich am Wellensittich etabliert werden. Hinsichtlich der Einordnung des Reproduktionsstatus war in erster Linie ein Absinken der steroidogenen Enzymaktivität von 3β-Hydroxysteroid-Dehydrogenase (HSD) und 17β-HSD-2 bei sexuell inaktiven gegenüber aktiven und intermediären Tieren zu verzeichnen. Auch der Androgenrezeptor (AR) wurde im Ruhestadium nicht mehr exprimiert. Die übrigen Steroidrezeptoren, steroidogenen Enzyme und Relaxinpeptide zeigten variable zelluläre Verteilungsmuster, die keine klare Aussage zum Fortpflanzungsstatus zuließen. Dennoch konnten anhand der Lokalisation dieser Faktoren in Keimzellen, somatischen Zellen des Hodens und Zellen des Nebenhodenepithels funktionelle Gesichtspunkte geklärt werden. Beispielsweise zeigte die Koexistenz des Östrogenrezeptors ERα und des steroidogenen Enzyms Aromatase in Hoden und Nebenhoden, dass nicht nur androgene Einflüsse in die Steuerung der Gonaden involviert sind. Auch der erstmalige Nachweis von Relaxin, Relaxin-like factor und ihren Rezeptoren in testikulären und epididymalen Zellen deutet darauf hin, dass diese die Funktion der beim Vogel nicht vorhandenen Prostata übernehmen.
Zudem ist der Transfer der etablierten immunzytochemischen Methoden auf sieben weitere Papageiengattungen (Nymphicus, Eolophus, Cacatua, Psittacus, Amazona, Ara, Cyanopsitta) gelungen. Auch hier konnten 14 Marker in verschiedenen Zellen von Hoden und Nebenhoden sichtbar gemacht werden. Die teilweise heterogene Verteilung der Marker in verschiedenen Zelltypen war eindeutig spezies-abhängig. Dies hat gezeigt, dass die beim Wellensittich mittels Immunzytochemie erzielten Resultate nur eingeschränkt auf andere Papageienspezies übertragbar sind. Entscheidend für die Beurteilung des Reproduktionsstatus ist daher die individuelle Auswahl der Marker in Abhängigkeit von der untersuchten Spezies.
Die Resultate dieser Studie liefern die Grundlage für weitere Forschungsansätze in der Reproduktionsdiagnostik von Papageienvögeln. Zum einen können die etablierten Marker in Analyse-Systemen zum Einsatz kommen, die nicht-invasiv gewonnene Medien (z. B. Faezes) untersuchen und vor allem in Zuchterhaltungsprogrammen bedrohter Arten hilfreich sind. Zum anderen ist die immunzytochemische Untersuchung von Hodenbioptaten pathologisch veränderter Hoden (z. B. Tumoren oder Entzündungen) als eine sinnvolle Ergänzung der Diagnostik von Infertilität bei männlichen Psittaziden anzusehen.
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Nolan, Kay. "The transmission dynamics of Toxoplasma gondii in sheep." Thesis, University of Warwick, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479313.
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Mohammed, Saleem. "Molecular studies on the protozoan parasite Toxoplasma gondii." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262211.
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Wheeler, Ruth Belinda. "Studies of the molecular biology of Toxoplasma gondii." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356985.
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Nickdel, Mohammad Barat. "Role of Th2 cytokines in Toxoplasma gondii infection." Thesis, University of Strathclyde, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248258.
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Henriquez, Fiona Luisa. "Recharacterization of Toxoplasma gondii dense granule protein GRA3." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273437.
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Frohnecke, Nora. "Funktionelle Charakterisierung des Ferredoxin Redoxsystems von Toxoplasma gondii." Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19075.
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Toxoplasmose ist weltweit eine der am häufigsten auftretenden parasitären Zoonosen mit einer geschätzten Infektionsrate von über 30%. Toxoplasma gondii (Phylum: Apicomplexa) besitzt ein Plastid ähnliches Organell, den Apicoplasten. In diesem befindet sich das einzig bekannte Redoxsystem, welches aus der Ferredoxin-NADP+-Reduktase und Ferredoxin (Fd) besteht. Fd als Elektonendonator liefert Elektronen an verschiedene essentielle Stoffwechselwege, wie der Isoprenoidvorstufen- und Liponsäuresynthese. Um die bei einem Elektronentransfer benötigte direkte Protein-Protein-Interaktion eingehend zu analysieren, wurde ein bakterielles Reverse Two Hybrid System verwendet, womit die Interaktion von TgFd und TgLipA gezeigt werden konnte. Da angenommen wird, dass Fd eine zentrale Rolle in verschiedenen Stoffwechselwegen übernimmt, ist für einen Fd Knockout ein komplexer biochemischer Phänotyp zu erwarten, der möglicherweise zum Absterben der Parasiten führt. Zur Untersuchung dessen wurden zwei komplementäre Wege verfolgt. Eine der Strategien basierte auf dem grundsätzlichen Nachweis, dass Fd unerlässlich für das Überleben von T. gondii ist. Mit Hilfe des DiCre Systems sollte ein definierter genetischer Fd Knockout hergestellt werden, welcher jedoch nicht zweifelsfrei generiert werden konnte. Bei der zweiten Strategie kam ein konditionales Knockdown System zur Anwendung, bei welchem die Expression des Fd Gens nach Induktion herabreguliert wird. Mit Hilfe dessen konnten weitreichende Auswirkungen der Fd Defizienz auf T. gondii gezeigt werden: die Fettsäuresynthese der im Apicoplasten synthetisierten Fettsäuren ist reduziert sowie die Motilität durch eine beeinträchtigte Isoprenoidsynthese verringert, wodurch insgesamt drastische Auswirkungen auf das Parasitenwachstum gezeigt werden konnten. Beide Stoffwechsel sind vom Elektronendonator Fd abhängig und durch die Fd Herabregulation betroffen. Die Ergebnisse unterstreichen die essentielle Rolle des Fd-Redoxsystems von T. gondii.Toxoplasmosis is one of the most common parasitic zoonoses world-wide, around 30% of human beings are infected. Toxoplasma gondii (phylum: Apicomplexa) contains a unique intracellular organelle derived from plastids, called apicoplast. The only known redox system in the apicoplast consists of the ferredoxin NADP+-reductase and its redox partner, ferredoxin (Fd). The latter donates electrons to different essential metabolic pathways in the apicoplast like the last two enzymes of the isoprenoid precursor biosynthesis and the lipoic acid synthesis. To dissect protein protein interactions for an electron transfer a bacterial reverse two hybrid system was used. The physical interaction of both proteins TgFd and TgLipA could be shown. Fd is supposed to play an important role in diverse metabolic pathways, hence a knock-out of the Fd gene is expected to generate a complex biochemical phenotype and be lethal to the parasite. Therefore two complementary approaches were used to analyze the role of TgFd in this context. The first strategy shall verify the essentiality of TgFd for the survival of T. gondii. It is based on the DiCre system whereby a defined genetic knock out of TgFd is produced. Respectives parasites have been generated, but at the end no genetic Fd knock out could be produced. In the second approach a conditional knock-down was generated, where the expression of the TgFd gene is repressed after induction. The Fd deficiency has wide ranging effects on T. gondii: The fatty acid synthesis of the apicoplast-synthesized fatty acids is reduced as well as the motility is decreased due to an affected isoprenoid synthesis. In total this leads to a dramatic inhibition of parasite growth. Both metabolic pathways depend upon the electron carrier Fd and thus are affected by Fd deficiency. The results underline the essential role of the ferredoxin redoxsystem of T. gondii.