Investigou-se a existência de relação entre células normais de triatomíneos, formas evolutivas do T.cruzi e hospedeiros mamíferos. Hemócitos do vetor de espécies hematófagas não infectadas (Triatoma infestans, T. palidipennis, Dipetalogaster maximus, Rhodnius prolixus e Panstrongylus megistus) foram reconhecidos por soros de pacientes e camundongos infectados com Trypanosoma cruzi, por meio da técnica de imunofluorescência, enquanto que os hemócitos de um inseto fitófago, Diactor billineatus (ninfas e adultos) não foram reconhecidos pelos mesmos soros. Uma parcial reação cruzada foi observada entre hemócitos de T. infestans e soros de portadores de leishmaniose , o que não ocorreu com as amostras de portadores de doenças autoimunes, infecção com HIV e indivíduos normais. O tratamento de hemócitos com metaperiodato de sódio aboliu a fluorescência, mostrando que antígenos carboidratos estão envolvidos. O uso de lectinas marcadas revelou que N acetil-d-glicosamina, manose, glicose e βgal fazem parte da estrutura celular. O immunoblotting com extrato de hemócitos foi realizado com soros de pacientes chagásicos crônicos antes e depois do tratamento específico. Estes soros de ambos casos foram absorvidos com tripomastigotas e epimastigotas. Um número considerável de bandas desapareceu nos soros tratados com tripomastigotas, mas não com epimastigotas. Proteínas de 61-70, 41-50, 31-40 e 21-30 kDa foram as envolvidas no processo de absorção. Após a quimioterapia, as bandas de 121-130, 91-100, 81-90 e 61-60 kDa desapareceram nos soros não absorvidos. Um grupo de camundongos fêmeas A/Sn foi imunizado com hemolinfa livre de hemócitos (HL) e outro grupo com hemócitos (Hc) e desafiados com 5x102 tripomastigotas sangüícolas.(cepa Y). Picos de parasitemia dos camundongos HL e Hc foram observados um ou dois dias após o grupo controle. Apesar da parasitemia de ambos os grupos ter sido baixa, o grupo HL apresentou 43% de mortalidade, enquanto que o grupo Hc mostrou apenas 14 % de mortalidade. As citocinas IFNγ e TNFα estão envolvidas no processo de proteção,\' assim como óxido nítrico e anticorpos líticos. Os hemócitos induziram uma redução de IL-10, inibindo a resposta Th2. Desde que os hemócitos e tripomastigotas compartilham epítopos comuns, epítopos de hemócitos devem ser melhor estudados em virtude de seu potencial uso no imunodiagnóstico, imunoproteção e avaliação terapêutica. / Immunological relationship between normal triatomine cells, developmental life-cycle stages of T. cruzi and infected mammal hosts was investigated. Hemocytes from uninfected hematophagous vector species of triatomines (Triatoma infestans, T. palidipennis, Dipetalogaster maximus, Rhodnius prolixus and Panstrongylus megistus) were recognized by sera from patients and mice infected with Trypanosoma cruzi, by means of immunofluorescence assay (IFA), whereas hemocytes from a phytophagous bug, Diactor billineatus (nymphs and adults) were not recognized by the same sera. Hemocytes from T. infestans were partially recognized by leishmaniasis sera, but, not by samples from patients with autoimmune diseases, HIV positive sera. The treatment of hemocytes with sodium metaperiodate practically abolished the fluorescence staining, indicating the presence of carbohydrate antigens. These antigens were revealed be comprised of N acetyl-D-glucosamine, mannose and glucose and βgal, by means of fluorescent labelled lectins. Sera from chronic chagasic patients before and after the chemotherapy were reactive with hemocytes of P. megistus on immunoblotting, and the same sera previously absorbed with formaldehyde fixed cultured epimastigotes as well trypomastigotes. On immunoblotting a substantial number of bands diminished with sera absortion with trypomastigotes, but not with epimastigotes. Proteins of 61-70, 41-50, 31-40 and 21-30 kDa were the major proteins involved in the process of serum absorptions. After chemotherapy, protein bands of 121-130, 91-100, 81-90 and 51-60 kDa disappeared in unabsorbed sera. A group of female A/Sn mice were immunized with hemolymph free of hemocytes (MHL) and other group with hemocytes (MHC). Animais were challenged with 5x102 bloodstream trypomastigotes (Y strain). Parasitemia peaks of MHL and MHC groups were observed one or two days after the control group. In spite of the parasitemia for both groups was about 63% lower than the control group, the mortality for the MHL was 43%, differing from the MHC, which was 14% only. The Cytokines, IFNγ and TNFα, were shown to be involved in the protection of immunized mice, and also the nitric oxide and complement dependent lytic antibodies. Hemocytes showed to play a role in the reduction of the IL-10 production, inhibiting Th2 response. Thus, hemocytes and trypomastigotes share common epitopes, and these epitopes are potentially useful for immunodiagnosis, immunopratection, and evaluation of chemotherapic efficiency in Chagas\' disease control.

Escherichia coli enteroinvasora (EIEC) e Shigella sp causam disenteria bacilar que é caracterizada pela invasão e destruição da mucosa do cólon humano. Amostras de EIEC possuem características bioquímicas, genéticas patogênicas semelhantes às espécies de Shigella, porém a doença causada por EIEC se apresenta numa forma mais branda e autolimitante. As células do epitélio intestinal participam ativamente da imunidade da mucosa, expressando e secretando uma série de mediad ores inflamatórios como citocinas, quimiocinas, moléculas de adesão e óxido nítrico. Para melhor entendimento da patogênese de EIEC, estudamos a resposta inflamatória modulada por este microrganismo em células epiteliais intestinais da linhagem Caco-2, comparando-a com Shigella flexneri. Células Caco-2 foram infectadas com EIEC ou S. flexneri por diferentes intervalos de tempo, para posterior analise da capacidade de invasão e disseminação bacterianas (UFC, PLAQUE ASSA Y), indução de morte celular (FACS), analise relativa de genes envolvidos no reconhecimento bacteriano e na resposta inflamatória (RT-PCR, RPA), dosagem de citocinas e quimiocinas pró-inflamatórias (ELISA) e óxido nítrico (GRIESS). Neste trabalho foi possível observar que: (i) a capacidade de disseminação e (ii) a indução da morte celular em células Caco-2 foi significativamente maior na infecção por S. flexneri do que EIEC; (iii) há diferenças em relação à expressão relativa de genes das células Caco-2 envolvidos no reconhecimento das duas cepas bacterianas. Foi evidenciado o papel essencial dos receptores intracelulares no reconhecimento bacteriano das células Caco-2, sendo a expressão relativa do mRNA do receptor intracelular Nod1 foi maior para EIEC quando comparado com S. flexneri; (iv) há diferenças significativas na cinética de produção de NO pelas células Caco¬2 infectadas, em que EIEC induziu mais precocemente a produção de NO quando comparado com S. flexneri. Estes dados sinalizam que as células epiteliais intestinais reconhecem e respondem de forma diferente frente a essas duas espécies bacterianas, apresentando uma resposta inflamatória mais eficiente no controle da infecção induzida por EIEC. / Escherichia coli enteroinvasive (EIEC) and Shigella sp cause bacillary dysentery which is characterized by the invasion and destruction of the human colon mucosa. Samples of EIEC have characteristics biochemical, genetic and pathogenic similar to those of Shigella species, however the disease caused by EIEC is more lenient. The cells of the intestinal epithelium actively participate in the mucosal immunity by expression and production of several inflammatory mediators such as cytokines, chemokines, adhesion molecules and nitric oxide. For better understanding of the EIEC pathogenesis, we studied the inflammatory response modulated by this microorganism in intestinal epithelial cells Caco-2, comparing it with Shigella flexneri. Caco-2 cells were infected with EIEC or S. flexneri during different intervals of time and analyzed the invasiveness and spread bacteria capacity (CFU, PLAQUE ASSAY), induction of cell death (FACS), analysis of genes involved in the recognition of bacterial and inflammatory response (RT-PCR, RPA), production of pro-inflammatory cytokines and chemokines (ELISA) and nitric oxide (NO) (GRIESS). In this work was possible to observe that: (i) the ability to spread and (ii) the induction of cell death in Caco-2 cells was significantly higher in S. flexneri infection than EIEC, (iii) there are differences regarding the relative expression of genes of Caco-2 cells involved in the recognition of two bacterial strains. It was highlighted the essential role of intracellular receptors in recognition of bacterial by Caco-2 cells, and the expression of mRNA of the intracellular receptor Nod 1 was higher for EIEC when compared with S. flexneri, (iv) there are significant differences in the kinetics of NO production by Caco-2 infected cells, EIEC induced a early NO production when compared with S. flexneri. These data indicate that the intestinal epithelial cells recognize and respond in a different way to these bacterial species and induce an inflammatory response more efficient in control of the infection induced by EIEC.

Larvas de cisticercos de Taenia crassiceps foram deixadas em repouso em TRIS 9mM pH 7,2 com 1mM EDTA até 180 minutos, os sobrenadantes coletados e processados nos 30, 60, 120 e 180 minutos, dando origem aos antígenos de excreção e secreção (ES 30; ES 60; ES 120 e ES 180). A caracterização do antígeno de excreção e secreção de larvas de Taenia crassiceps foi feito por SDS-PAGE e imunoblot utilizando anticorpos monoclonais (AcMos) anti-T. crassiceps e anti-T. solium e anticorpos humanos. Os resultados mostraram que o rendimento do antígeno ES foi menor nos primeiros 30 minutos (0,4 µg) por larva quando comparado os demais ES (ES 60: 2,4 µg; ES 120: 2,9 µg; ES 180: 2,5 µg). O SDS-PAGE confirmou que no ES 30 há menos proteínas. No imunoblot, o ES 180 mostrou que 6 AcMos (anti-LV-Tcra; anti-ES-Tcra; anti-LV-Tso: A3; anti-T-Tso: B4, B11 e A6) reconheceram apenas as frações 18- e 14-kDa do antígeno ES 180. Os AcMos anti-E-Tso (B8) e anti-LV-Tso (B6) não reconheceram frações do antígeno ES 180. Anticorpos presentes em amostras humanas de pacientes com NC reconheceram as frações protéicas entre 94- a 30-kDa e as de 18- e 14-kDa. Utilizando antígeno ES 180 e amostras de soros de pacientes supostamente saudáveis (GC), foram identificadas proteínas acima de 30-kDa e somente uma amostra reconheceu a de 16- kDa, anômala em relação ao perfil 18- e 14-kDa. As amostras de soro de pacientes com outras parasitoses mostraram reatividade com frações ≥ de 30-kDa do ES 180 e o maior índice de reatividade foi com a proteína 71-KDa. Um total de 77%; 70%; 60% e 70% das amostras de pacientes com toxocaríase, esquistossomose mansônica, hidatidose e Chagas, respectivamente, reconheceram a fração 71-kDa do ES 180. O antígeno ES pode contribuir com futuros estudos abordando a complexa relação parasito hospedeiro na cisticercose e na produção de vacinas para o uso em suínos. / Cysticercus Larvae of Taenia crassiceps were maintained in TRIS 9mM pH 7,2 with 1mM EDTA for 180 minutes; the supernatant was collected and processed at 30; 60; 120 and 180 minutes, originating excretion-secretion antigens (ES 30; ES 60; ES 120 and ES 180). The characterization of the ES antigen was conducted through SDS-PAGE and immunoblot using anti-T. crassiceps and anti-T. solium monoclonal antibodies (AcMos) and human antibodies. The results showed that the production of ES antigen was lower in the first 30 min. (0,4 µg) compared with the others (ES 60: 2,4 µg; ES 120: 2,9 µg; ES 180: 2,5 µg). The SDS-PAGE confirmed that ES 30 presented less protein. By immunoblot,6 AcMos (anti-LV-Tcra; anti-ES-Tcra;anti-LV-Tso: A3; anti-T-Tso: B4, B11 and A6) have recognized only the 18- and 14-kDa fractions of the ES 180. The anti-E-Tso (B8) and the anti-LV-Tso (B6) AcMos did not recognize any fractions. Antibodies from human samples NC recognized the proteins from 94- to 30-kDa and from 18- and 14-kDa. Using serum samples of apparently healthy individuals (GC), the ES 180 antigen showed proteins > 30-kDa and one sample recognized the 16-kDa fraction, anomalous when compared to the 18- and 14-kDa fractions. The serum samples of subjects with other parasitoses showed reactivity ≥ 30-kDa, more frequently with 71-KDa protein. A total of 77%; 70%; 60% and 70% of the samples from subjects presenting toxocariasis, esquistossomose mansonic, hydatidosis and Chagas disease, respectively, recognized the 71-kDa fraction of ES 180. The ES antigen may contribute to further studies on the complex cysticercosis parasite/host relation as well as for the production of vaccines for swine.

In wireless communication there is commonly much unnecessarycommunication made in directions not pointing towards the recipient. Normallyomni directional antennas are being used which sends the same amount ofenergy in all directions equally. This waste of energy reduces the lifetime ofbattery powered units and causes more traffic collisions than necessary. Oneway of minimizing this wasted energy and traffic collisions, is to use anothertype of antenna called “smart antenna”. These antennas can use selectableradiation patterns depending on the situation and thus drastically minimize theunnecessary energy waste. Smart antennas also provide the ability to sense thedirection of incoming signals which is favorable for physical layout mappingsuch as orientation.This thesis presents the prototyping of a new type of smart antenna called theSPIDA smart antenna. This antenna is a cheap to produce smart antennadesigned for the 2.4 GHz frequency band. The SPIDA smart antenna can usesixty-four different signal patterns with the control of six separate directionalmodes, amongst these patterns are six single direction patterns, an omnidirectionalsignal pattern and fifty-six combi-direction patterns. The thesispresents complete building instructions, evaluation data and functional driversfor the SPIDA smart antenna.

Les investigations présentées dans ce mémoire de doctorat portent sur la synthèse d’antennes à éléments parasites à polarisation circulaire. Une stratégie de conception rapide et efficace est développée et mise en oeuvre pour synthétiser des diagrammes de rayonnement à multiples objectifs. Des éléments parasites peuvent ainsi être associés à d’autres antennes pour en améliorer les performances. Deux antennes ont été imaginées. Un premier démonstrateur d’AEP directive à polarisation circulaire et à bande élargie a été conçu. Ce démonstrateur qui se compose de l’association de 18 dipôles parasites avec une antenne spirale logarithmique a été fabriqué et mesuré. Un second prototype d’AEP a été inventé dans le cadre d’un projet spatiale «Antenne Isoflux Bande-X pour nano-satellite». L’antenne compacte a été développée pour supporter les débits de transmission des futures missions des plateformes Nano-Satellite « Cube-Sat ». Ce prototype associe une antenne patch avec une distribution de 12 dipôles parasites pour réaliser une couverture Isoflux en polarisation circulaire. Cette antenne a été mesurée sur sa plateforme d’accueil. / The investigations presented in this thesis propose the synthesis of circularly polarized antennas with parasitic elements. An innovative and effective strategy is developed and implemented to synthesize a multi-objective radiation patterns. Parasitic elements can also be associated with other antennas to improve the performances. Two antennas were suggested. The first one represents a wide band circularly polarized directive antenna with parasitic elements. This demonstrator consists of the combination of 18 parasitic dipoles with a logarithmic spiral antenna; this antenna was manufactured and measured. The second antenna is a part of a space project « Isoflux X-Band antenna for Nano-Satellite». This compact antenna has been developed to support transmission rates for future mission.

Doctor of Philosophy / Department of Chemistry / Duy H. Hua / I. Ovalicin is a natural product isolated from the culture of fungus Pseudorotium ovalis Stolk, it selectively inhibit type 2 methionine amino-peptidase (MetAP 2), which related to many physiological activities such as angiogenesis. Total synthesis of [plus or minus] ovalicin, its C4(S*), C4(S*)C5(S*) stereo-isomers, and C5 regio-isomer were synthesized via an intramolecular Heck reaction of (Z)-3-(t-butyldimethyl silyloxy)-1-iodo-1,6-heptadiene utilizing a catalytic amount of palladium acetate. Subsequent epoxidation, dihydroxylation, methylation (or stereochemistry inversion before or after methylation) and oxidation led to a variety of ketones, key intermediates for synthesis of ovalicin and its analogues. Introduction of side-chain to ketones by lithium (Z)-6-methylhepta-2,5-dien-2-ide and following functional group transformation led to ovalicin and its analogues. Anti-trypanosomal activities of various ovalicin analogues and synthetic intermediates were evaluated. II. Bio-based polymers from vegetable oils are renewable and environment-friendly materials. Dihydroxylated, trihydroxylate, tetrahydroxylated and hexahydroxylated triglycerides, triamino and triisopropylamino glycerides were synthesized from model triglyceride glyceryl trioleoate. These monomers were cross-linked with 1, 4-phenylene diisocynate to make polyurethanes and polyureas. The physical properties of these polymers were examined by gel content and swelling value measurements, thermodynamic and viscoelastic properties were studied from TGA, DSC and DMA measurements. The structure-property relationship was discussed based on these measurements. III. Diacetylenic fatty acids were widely applied in material science to regulate alignment on surface and stabilize self-assembled nanomaterials. A novel synthetic method of diacetylenic fatty acids from vegetable oils was developed. Its self-assembling properties on alumina surface were measured and discussed.

La gestion des nématodes phytoparasites (NPP) est un enjeu capital pour de nombreux opérateurs agricoles. Au Maroc, le développement d’une agriculture intensive dans le cadre du « Plan Maroc Vert » va nécessairement induire l’émergence de pathologies végétales, dont des nématoses. Dans le cas de l’olivier, ils mettent en péril la production en pépinière et dans les vergers à haute-densité. D’autre part, les pépinières sont une source majeure d’introduction des NPP en vergers, par transplantation de plants enracinés.C’est la raison pour laquelle une étude de la diversité des communautés de NPP a été conduite dans 25 pépinières localisées dans les régions les plus productrices au Maroc (Souss, Haouz, Guérouane, Jbala). Un total de 305 échantillons de sol ont été analysés. Les NPP détectés appartiennent aux familles des Hoplolaimidae (Helicotylenchus spp., Rotylenchus spp.), des Telotylenchidae (Tylenchorhynchus spp.), des Meloidogynidae (Meloidogyne spp.) et des Tylenchidae (Trichotylenchus spp.), etc. Bien qu’aucun symptôme n’ait été observé sur les racines, l’abondance moyenne de ces genres était très élevée (jusqu'à 56.640 individus/dm3 de sol). Une étude biochimique (PAGE) et moléculaire (SCARS) a également porté sur la diversité des nématodes à galles du genre Meloidogyne, principaux ravageurs de l’olivier. Elle a indiqué une dominance de M. javanica (72%) sur M. incognita (25.5%), tandis que M. arenaria n’a été détectée que dans une seule pépinière. Cette étude montre la nécessité absolue pour les pépiniéristes de proposer une garantie sanitaire des plants à travers une traçabilité des substrats.Afin de contrôler le développement des NPP en pépinière, puis en vergers après transplantation, la lutte microbiologique à l’aide de champignons nématophages (CNP) s’avère une alternative adaptée aux pépinières (inoculation aux substrats). Ainsi, 70 souches de champignons telluriques ont été isolées, dont une grande diversité d’Orbiliaceae possédant des organes de capture (Arthrobotrys spp., Dreschlerella spp., Monacrosporium spp.) et d’Hypocreaceae toxiques (Trichoderma asperellum , T. harzianum, T. longibrachiatum, Talaromyces assiutensis). Des espèces oviparasites telles que Paecilomyces lilacinus (dominante) et Pochonia chlamydosporia étaient également présentes. Plusieurs espèces endoparasites ont aussi été observées telles que Catenaria anguilullae, Nematoctunus leiosporus et Haptoglossa heterospora. Les tests de prédation in vitro ont révélé que T. assiutensis est capable de parasiter 100% des juvéniles de M. javanica. Les souches d’Orbiliaceae induisent une mortalité de 50 à 80% des juvéniles. Des analyses multivariées (ACP, co-inertie, K-tableaux) ont permis d’identifier l’impact majeur des variables climatiques (pluviométrie et température minimale) et de l’origine des substrats de culture (habitats écologiques) sur la diversité des communautés de NPP et de CNP. Les amendements minéraux (NPK), la matière organique, l’acidité et la texture argileuse des substrats ont un impact non négligeable. Les variétés multipliées n’ont aucun effet. L’analyse des co-structures entre les communautés de NPP et de CNP a indiqué une corrélation entre les Orbiliaceae et Meloidogyne spp., ce qui confirme l’intérêt de ces CNP comme agents de lutte biologique pour la gestion de ces NPP.L’étude de la physiologie de croissance et de sporulation des souches a révélé que les souches de Trichoderma spp. ont les fitness les plus élevées alors que les Orbiliaceae ont une croissance et une sporulation faible. Les études diligentées dans le cadre de cette thèse (i) confirment que la diversité des communautés de NPP sont des indicateurs pertinents pour évaluer la santé des substrats dans les pépinières oléicoles à des fins de certification des oliviers, et (ii) ouvrent des perspectives de développement de stratégies de gestion microbiologique de ces parasites respectueuse de l’environnement. / The management of plant parasitic nematodes (PPN) is a major challenge for many agricultural operators. In Morocco, the development of an intensive agriculture in the " Morocco Green Plan" will necessarily induce the emergence of plant diseases, including nematodes. On olive tree, they imperil production in nurseries and in high-density orchards. On the other hand, nurseries are a major source of introduction of PPN in orchards by transplanting rooted plants. In this context, the study of the diversity of PPN communities was conducted in 25 olive nurseries located in the main olive producing areas in Morocco (Souss, Haouz, Guerouane, Jbala). A total of 305 soil samples were analyzed. The NPP detected belonged to the Hoplolaimidae (Helicotylenchus spp., Rotylenchus spp.), Telotylenchidae (Tylenchorhynchus spp.), Meloidogynidae (Meloidogyne spp.) and Tylenchidae (Trichotylenchus spp.) families. Although no symptom have been observed on roots, the mean abundance of these genera was very high (up to 56,640 individuals/dm3 of soil). Biochemical (PAGE) and molecular (SCARS) diagnosis was focused on root knot nematodes (Meloidogyne spp.), that are major pests of olive trees. It indicated a dominance of M. javanica (72%) on M. incognita (25.5%), while M. arenaria was detected in one nursery only. This study shows the necessity for nurse producers to provide a health guarantee seedlings through traceability of substrates.To control the development of PPN in nurseries and orchards after transplantation, microbiological control using nematophagous fungi (NF) proves a suitable alternative to nurseries (inoculation to substrates). Thus, 70 soil fungal strains were isolated, including a large diversity of Orbiliaceae with trapping organs (Arthrobotrys spp., Dreschlerella spp., Monacrosporium spp.) and of toxic Hypocreaceae (Trichoderma asperellum, T . harzianum, T. longibrachiatum, Talaromyces assiutensis). Egg-parasitic species such as Paecilomyces lilacinus (dominant) and Pochonia chlamydosporia were also present. Several endoparasitic species were also observed as Catenaria anguilullae, Nematoctunus leiosporus and Haptoglossa heterospora. In vitro predation tests revealed that T. assiutensis was able to kill 100% of the M. javanica juveniles. The Orbiliaceae strains killed 50 to 80% of the juveniles. Multivariate statistical analyses (PCA, co-inertia, K-tables) pointed out the main impact of climate variables (rainfall and minimum temperatures) and of the substrate origins (ecological habitats) on the diversity of both PPN and NF communities. Mineral amendments (NPK), organic matter, acidity (pH) and clayey substrates have less significant impacts. The varieties multiplied had no effect.Co-structure analyses between PPN and NF communities indicated significant correlations between Orbiliaceae and Meloidogyne spp., which confirms the interest of NF as biocontrol agents for the management of PPN.The experimental monitoring of growth and sporulation physiology of the NF strains exhibited high fitness for the Trichoderma species while the Orbiliaceae have low growth and sporulation.The studies commissioned as part of this thesis (i) confirm that the diversity of PPN communities may be relevant indicators to assess the health of substrates in olive nurseries for certification purposes, and (ii) offer future prospects for the development of microbiological management strategies of these parasites respectful of the environment.

One of Africa’s neglected tropical diseases, African Trypanosomiasis, is not only fatal but also has a crippling impact on economic development. Heat shock proteins play a wide range of roles in the cell and they are required to assist the parasite as it moves from a cold blooded insect vector to a warm blooded mammalian host. The expression of heat shock proteins increases during these heat shock conditions, and this is considered to play a role in differentiation of these vector-borne parasites. Heat shock protein 70 (Hsp70) is an important molecular chaperone that is involved in protein homeostasis, Hsp40 acts as a co-chaperone and stimulates its intrinsically weak ATPase activity. In silico analysis of the T. brucei genome has revealed the existence of 12 Hsp70 proteins and 65 Hsp40 proteins to date. A novel Hsp70, TbHsp70.c, was recently identified in T. brucei. Different from the prototypical Hsp70, TbHsp70.c contains an acidic substrate binding domain and lacks the C-terminal EEVD motif. By implication the substrate range and mechanism by which the substrates are recognized may be novel. The ability of a Type I Hsp40, Tbj2, to function as a co-chaperone of TbHsp70.c was investigated. The main objective of this study was to biochemically characterize TbHsp70.c and its partnership with Tbj2 to further enhance our knowledge of parasite biology. TbHsp70.c and Tbj2 were heterologously expressed and purified and both proteins displayed chaperone activities in their ability to suppress aggregation of thermolabile MDH. TbHsp70.c also suppressed aggregation of rhodanese. ATPase assays revealed that the ATPase activity of TbHsp70.c was stimulated by Tbj2. The targeted inhibition of the function of heat shock proteins is emerging as a tool to combat disease. The small molecule modulators quercetin and methylene blue are known to inhibit the ATPase activity of Hsp70. However, methylene blue did not significantly inhibit the ATPase activity of TbHsp70.c; while quercetin, did inhibit the ATPase activity. In vivo heat stress experiments indicated an up-regulation of the expression levels of TbHsp70.c. RNA interference studies showed partial knockdown of TbHsp70.c with no detrimental effect on the parasite. Fluorescence microscopy studies of TbHsp70.c showed a probable cytoplasmic subcellular localization. In this study both TbHsp70.c and Tbj2 demonstrated chaperone activity and Tbj2 possibly functions as a co-chaperone of TbHsp70.c.

Pour faire cohabiter les nombreuses technologies radios, les terminaux mobiles nécessitent une miniaturisation de plus en plus poussée des antennes. Toutefois, les performances d'antennes ont des limites fondamentales liées à leurs dimensions physiques. La littérature met en évidence que les réseaux superdirectifs permettent de dépasser la limite de Harrington sur la directivité et que des antennes adaptées par des circuits non-Foster peuvent dépasser la limite de Bode-Fano sur la bande passante. Les contributions essentielles de ce travail de thèse consistent en la conception deréseaux d'antennes superdirectifs et d'antennes adaptées par des circuits non-Foster comme solutions possibles pour l'amélioration des performances des Antennes Electriquement Petites (AEP). Dans une première partie, un convertisseur d'impédance négative est réalisé pour obtenir des condensateurs de valeurs négatives de façon à adapter des antennes miniatures sur une large bande de fréquence. Dans la deuxième partie de ces travaux, les limites théoriques des réseaux d'antennes superdirectifs sont évaluées et une approche simple et pratique permettant la conception de ces réseaux à partir d'éléments parasites est proposée. L'intégration des AEP superdirectives sur des cartes de circuit imprimé est étudiée et les difficultés de mesure de ce type d'antenne sont évaluées. A partir de ces résultats, une nouvelle stratégie pour réaliser des réseaux compactes 3D ou planaires à polarisation linéaire ou circulaire en utilisant des éléments superdirectifs est présentée. / For supporting different wireless technologies, mobile terminals require significant miniaturization of antennas. However, antennas performance has some fundamental limits related to their physical dimensions. The available theory shows that superdirective arrays can exceed Harrington’s limit on antenna directivity and non-Foter matched antennas can surpass Bode-Fano limit on antenna bandwidth. Therefore, this work focuses on the design of superdirective antenna arrays and non-Foster matched antennas as possible solutions for improving the performance of Electrically Small Antennas (ESAs). In the first part: a Negative Impedance Converter (NIC) is designed to have a very small negative capacitor. The circuit is evaluated in terms of gain, stability and linearity. Then, the circuit is used to match several small antennas in the UHF band. In the second part: the theoretical limits of superdirective antenna arrays are studied. A simple and practical approach to design parasitic antenna arrays is proposed. The integration of superdirective ESAs in Printed Circuit Boards (PCBs) is studied and the difficulties of measuring this type of antennasare evaluated. A new strategy for the design of 3D or planar compact arrays, with linear or circular-polarization, using superdirective elements is presented.

Na fase crônica da doença de Chagas, 70% dos pacientes são assintomáticos, 20-30% apresentam a forma cardíaca e 8% a digestiva. A influência da heterogeneidade genética das cepas de Trypanosoma cruzi na evolução da forma clínica foi cogitada. Neste trabalho, utilizamos PCRs para genes do maxicírculo de T. cruzi para caracterizar parasitas isolados de 75 pacientes com a forma assintomática ou cardíaca. Verificamos que os genes que codificam as subunidades 7 (ND7) e 4 (ND4) da NADH desidrogenase (complexo I mitocondrial) apresentam deleções em algumas cepas. No entanto, não observamos correlação entre as deleções nos genes e as formas clínicas. Investigamos alguns parâmetros do funcionamento da mitocôndria em cepas controle e com mutações. Verificamos que as deleções em ND7 ou ND4 não afetam a velocidade de consumo de oxigênio em epimastigotas permeabilizados com digitonina, concluindo que o complexo I mitocondrial não é funcional neste estágio. Observamos que os níveis de produção de H2O2 pela mitocôndria não guardam relação com a presença das mutações. / In the chronic phase of Chagas disease, 70% of the patients are asymptomatic, 20-30% develop the cardiac form and 8% the digestive form. The influence of the genetic heterogeneity of Trypanosoma cruzi strains in the outcome of the clinical presentation has been considered. In this study, we employed PCR assays targeted to T. cruzi maxicircle genes to genotype parasite isolates from 75 patients with the asymptomatic or cardiac forms. We verified that the genes that code for subunits 7 (ND7) and 4 (ND4) of the NADH dehydrogenase (mitochondrial complex I) show deletions in some strains. Nevertheless, we found no correlation between the presence of the deletions and the clinical presentations. We investigated some mitochondrial functional parameters in control and mutant strains. We observed that deletions in ND7 or ND4 do not affect the rate of oxygen consumption in epimastigotes permeabilized with digitonin. We conclude that complex I is non-functional in this stage. We observed no correlation between mitochondrial production of H2O2 and the gene deletions.