Submitted by (edna.saturno@ufrpe.br) on 2016-11-08T11:46:42Z No. of bitstreams: 1 Valeria Rosa dos Santos.pdf: 246353 bytes, checksum: da0bb55577698ef497d084dfe2ec9714 (MD5) / Made available in DSpace on 2016-11-08T11:46:42Z (GMT). No. of bitstreams: 1 Valeria Rosa dos Santos.pdf: 246353 bytes, checksum: da0bb55577698ef497d084dfe2ec9714 (MD5) Previous issue date: 2013-05-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The aim of this study was to evaluate the occurrence of Immunoglobulin G antibodies anti-Trypanosoma vivax in bovine cattle from the east region of Alagoas State, Brazil, and associate serum-positive frequency with epidemiologic data. For this purpose, a questionnaire was applied during the blood sampling. A total of 199 serum samples from four cities were submitted to Indirect Immunofluorescence Test (IIFT). Data were analyzed by Pearson´s chisquare test for a 5% significance level. The results showed that 23, 6% (47/199) of the samples were serum-positives for T. vivax. The frequencies, by municipalities varied from 10.1% to 41.2%. The chi-square values revealed an association between positive frequency and semi-intensive breeding as well with herd’s purpose double. It is concluded that preventive measures should be adopted. / No presente estudo objetivou-se detectar a ocorrência de anticorpos IgG anti-Trypanosoma vivax em rebanhos bovinos de propriedades rurais localizadas na Região Leste do estado de Alagoas e avaliar a associação da frequência de animais soropositivos com dados epidemiológicos. Foram testadas 199 amostras de soro sanguíneas de bovinos procedentes de quatro municípios, através da técnica de Reação de Imunofluorescência Indireta. Os dados foram analisados estatisticamente por meio do teste Qui-quadrado de Pearson, com nível de significância de 5%. Obteve-se 23,6% (47/199) de soropositividade com prevalência da infecção por T. vivax mais alta (p<0,05) em rebanhos com o sistema de criação semi-intensivo e de aptidão mista. Conclui-se em evidência sorológica por T. vivax como um agente circulante em rebanhos bovinos e que medidas preventivas e de controle devem ser adotadas.

Made available in DSpace on 2014-10-09T12:35:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:03:51Z (GMT). No. of bitstreams: 0 / Os íons terras raras apresentam propriedades espectroscópicas diferenciadas e números de coordenação entre 6 e 12 e seu estado de oxidação mais comum é o íon trivalente. Apesar de esses íons apresentarem uma baixa intensidade de luminescência, em função de sua baixa absortividade molar, esses são capazes de formar complexo onde o ligante absorva luz e transfira para o centro metálico essa energia, fenômeno conhecido como efeito antena. Essas propriedades tornam os seus complexos alvos de estudos como marcadores em ensaios imunoluminescentes, aliado ao uso de nanopartículas poliméricas. Todos esses fatores podem ser utilizados para a montagem de uma metodologia para o diagnóstico da doença de Chagas, doença tropical negligenciada, que apesar de seus mais de 100 anos após descoberta, ainda possui diversas questões em aberto e sem estudo aprofundado. Dessa maneira, propomo-nos a sintetizar e caracterizar nanopartículas de PHB misturadas aos complexos de terras raras, especificamente, complexos -dicetona - Tb3+ , Sm3+ , Gd3+, ou Eu3+. Pretende-se ligar essas nanopartículas a um espaçador como o glutaraldeído ou então diretamente a um anti-IgG humano e assim, num acoplamento antigeno-anticopo verificar sua emissão de luminescência para detecção de soro positivo para a doença. Dessa forma, obtém-se um biomarcador luminescente para diagnóstico da doença de Chagas. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-08-22T17:14:03Z No. of bitstreams: 2 Dissertação - Darling Mélany de Carvalho Madrid - 2017.pdf: 9281142 bytes, checksum: 7c28bb567493636c0dd23e77fa2de0ff (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-09-15T12:12:53Z (GMT) No. of bitstreams: 2 Dissertação - Darling Mélany de Carvalho Madrid - 2017.pdf: 9281142 bytes, checksum: 7c28bb567493636c0dd23e77fa2de0ff (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-09-15T12:12:53Z (GMT). No. of bitstreams: 2 Dissertação - Darling Mélany de Carvalho Madrid - 2017.pdf: 9281142 bytes, checksum: 7c28bb567493636c0dd23e77fa2de0ff (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-07-31 / Trypanosoma vivax (Ziemann, 1905) is a protozoon responsible for causing trypanosomiasis in bovines, a disease currently increasing in Brazil and, in the state of Goiás, it was first identified in 2015. As it causes abortion, lethality and greatly diminishes milk production, trypanosomiasis may cause significant losses to farmers, especially those working with milk production. However, there is not much information about this protozoon in Brazil. As it is necessary to gather more knowledge about isolates in the country to evaluate the disease real prevalence, impact in economy and, more importantly, develop control programs, this work proposed evaluate the morphometry of this parasite in scanning electron microscopy and the efficacy of different disinfectants in its elimination. Scanning electron microscopy is a highresolution technique used to analyze the external structures of the parasite, which shows morphometric differences between Latin America and Brazilian isolates. In this work, it was shown that there is no size difference among isolates found in Brazil and Goiás. The results of disinfectants efficacy evaluation to eliminate this agent have shown that many disinfectants commonly found in the market may be used. This information may be applied directly in farms to help control infection focus and contribute in reducing the disease impact in Brazilian milk production. / Trypanosoma vivax (Ziemann, 1905) é o protozoário responsável por causar a tripanossomíase em bovinos, doença que atualmente expressa caráter epidêmico no Brasil e, no estado de Goiás, foi identificada pela primeira vez em 2015. Por ocasionar aborto, letalidade e grande queda de produção de leite, a tripanossomíase pode gerar grandes prejuízos ao produtor, principalmente os que trabalham com bovinocultura de leite. Apesar disto, ainda não há muitas informações disponíveis sobre este protozoário no Brasil. Considerando a necessidade de conhecer mais as características dos isolados presentes no país a fim de avaliar sua prevalência real, impacto na economia e, principalmente, desenvolvimento de programas de controle, este trabalho se propôs avaliar a morfometria do parasito em microscopia eletrônica de varredura e a eficácia de diferentes desinfetantes na sua eliminação. A microscopia eletrônica de varredura é uma técnica de alta resolução empregada para analisar a estrutura externa do parasito, que apresenta diferenças morfométricas entre os isolados na América Latina e no Brasil. Neste trabalho, ficou evidenciado que não há diferença de tamanho entre os isolados encontrados no Brasil e em Goiás. Os resultados da avaliação da eficácia dos desinfetantes em eliminar o agente demonstram que diversos desinfetantes comumente encontrados no mercado podem ser empregados. Estas informações podem ser aplicadas diretamente em propriedades para auxiliar no controle de surtos e contribuir na redução dos impactos causados nos rebanhos bovinos de leite brasileiros.

As doenças tropicais têm um grande impacto sobre a saúde em países de baixa renda, estando relacionadas com condições de pobreza e desigualdade. A tripanossomíase africana é uma infecção parasitaria negligenciada incluída na agenda da Organização Mundial de Saúde. Esta enfermidade é causada pelo Trypanosoma brucei gambiense e Trypanosoma brucei rhodesiense, sendo transmitida pela mosca tsé-tsé (Glossina sp.) e geralmente fatal se não tratada. Os fármacos usados no seu tratamento são ineficazes, difíceis de administrar e causam severas reações adversas. Portanto, existe a necessidade do desenvolvimento de alternativas quimioterápicas eficazes e seguras. Assim, a enzima fosfoglicerato mutase (PGAM) surge como um importante alvo molecular. Esta enzima esta envolvida no metabolismo de glicose, sendo necessária para a viabilidade do parasito. Somado a isso, ela difere da enzima dos hospedeiros permitindo a identificação de inibidores específicos. Não obstante, esforços têm sido realizados para identificar inibidores da PGAM, bem como para elucidar sua estrutura e mecanismo de reação. Nosso propósito é obter o modelo de alta resolução desta macromolécula sem ligantes e conseqüentemente analisar a mudança de conformação que esta sofre ao se ligar ao seu substrato natural. A PGAM de Trypanosoma brucei obtida na expressão e purificação mostrou-se cataliticamente ativa nos ensaios cinéticos. Por experimentos de cromatografia de exclusão molecular observamos que a amostra purificada se comportava na forma de monômero. Dados de difração de raios-X foram coletados para cristais da macromolécula obtidos na ausência de ligantes. A estrutura cristalográfica foi resolvida a 2.3 Å, apresentando um dímero na unidade assimétrica. Ambas as moléculas do dímero estavam na forma livre e apresentava grande diferença conformacional se comparadas com as PGAMs de estruturas conhecidas que estão ligadas ao substrato ou produto natural. Por espalhamento de raios-X a baixos ângulos confirmamos que a enzima é monomérica em condições que mimetizam a fisiológica. A mudança conformacional induzida pelo ligante não afeta a topologia dos dois domínios da PGAM. Entretanto, há mudanças nos ângulos torcionais da cadeia principal dos laços que conectam os domínios da proteína. Além disso, o metal cobalto parece estar envolvido na estabilização da estrutura terciária da PGAM na conformação livre. Finalmente, este novo modelo estrutural pode contribuir para o esforço internacional de desenvolver fármacos tripanocidas / Tropical diseases represent a major burden on population health in low-incoming countries, being related to poverty and social disadvantage. African trypanosomiasis is a neglected parasitic infection on the agenda of World Health Organization. This disorder is caused by Trypanosoma brucei gambiensis and Trypanosoma brucei rhodesiensis, transmitted by the tsetse fly (Glossina sp.), and usually fatal if untreaded. The drugs used in the treatment are ineffective, difficult to administer, and cause severe adverse reactions. Therefore, there is a need to develop effective and safe chemotherapies. Thus, the enzyme phosphoglycerate mutase (PGAM) emerges as an important molecular target. This enzyme is involved in glucose metabolism, and is necessary for viability of the parasite. Moreover, it differs from the host enzyme allowing the identification of specific inhibitors. Nevertheless, efforts have been made in identifying PGAM inhibitors and to elucidate their structure and mechanism of reaction. Our purpose is to obtain the high resolution model of the macromolecule free from ligands and consequently to analyze the change in conformation that undergoes upon binding to its natural substrate. Trypanosoma brucei PGAM obtained in the expression and purification was shown to be catalytically active in the kinetics assays. In the size exclusion chromatography we observed that the purified sample behaves as a monomer. X-ray diffraction data were collected for crystals of the macromolecules obtained in the absence of ligands. The crystal structure was solved to 2.3 Å, showing a dimmer in the asymmetric unit. Both molecules of the dimmer were in free form, and had a large conformational difference compared with those of know PGAM structures that are connected to the natural substrate or product. Small angle X-ray scattering confirm that the enzyme is monomeric under conditions that mimic the physiological. Ligand-induced conformational change does not affect the topology of the two domains of the PGAM. However, there are changes in torsional angles of the main chain of the loops that connect the protein domains. Additionally, the metal cobalt seems to be involved in stabilizing the tertiary structure of PGAM in the free conformation. Finally, this new structural model may contribute to the international effort to develop trypanocidal drugs.

Lipid metabolism in Trypanosoma brucei, the causative agent of African sleeping sickness, differs from its human host, allowing a plethora of novel drug targets to be discovered and validated. Cytidine diphosphate diacylglycerol (CDP-DAG) is a central lipid intermediate produced by the enzyme CDP-DAG synthase (CDS), but nothing was known about CDS in T. brucei. Only one gene encodes CDS in Trypanosoma brucei (Tb927.7.220) and this was shown to encode a functional CDS by overexpression in E. coli and complementation of a yeast CDS null, which was created during this study. Expression and activity of TbCDS was confirmed in T. brucei, and was shown to be essential in both life cycle stages. Disruption of TbCDS altered the lipid profile of T. brucei, confirming a central role for CDP-DAG in phospholipid synthesis. Biochemical and morphological characterisation of mutants in TbCDS expression elucidated at least two separately localised and regulated pools of CDP-DAG and phosphatidylinositol in T. brucei. In bloodstream form these pools are localised to the Golgi and the ER, however in procyclics it is possible that both of these pools are localised to the Golgi, since no phosphatidylinositol synthase protein was detected in the ER of procyclics. Reduction in TbCDS was shown to affect cell cycle regulation and Golgi segregation possibly due to a depletion of phosphorylated phosphatidylinositols (PIPs). These studies also indicate that phosphatidylglycerol may be synthesised by the phosphatidylglycerol-phosphate synthase which may be capable of using phosphatidylserine as a substrate in a headgroup swapping reaction. TbCDS has now been genetically validated as a drug target, and has highlighted novel aspects of lipid biosynthesis in T. brucei. Collectively, these findings highlight the central role played by TbCDS and the new knowledge gained here may lead to the discovery and validation of other novel drug targets against African sleeping sickness.

Human African Trypanosomiasis (HAT) is a vector-borne disease transmitted by the bite of the tsetse fly that results in high human morbidity and mortality. The propagation of the disease has been linked to environmental factors, and understanding the vector’s habitat is vital to its control. There is no HAT vaccine, but biological control of the vector has been successful in reducing HAT incidence. However, in recent years the disease has re-emerged and spread. Due to insufficient knowledge of HAT endemic foci, the disease management remains challenging. To achieve effective deployment of control strategies, accurate knowledge of the spatial distribution of the HAT vector is vital. The current study is based in Nigeria, and looks at part of Delta State, and a part of Jigawa State, in which HAT has been identified. The work utilizes remote sensing satellite imaging and fuzzy logic to develop a HAT vector habitat classification scheme, to explore the dynamics of HAT propagation. The goal was to develop a surveillance methodology to identify factors that influence HAT epidemiology. Land cover and ancillary data were integrated to classify HAT vector habitat using geospatial-fuzzy multicriteria analysis. The work highlights the significance of geospatial techniques where epidemiological data are limited, for improving understanding of HAT. This study helped distinguish HAT vector habitat into different zones (breed, feed and rest), which allowed the direction and magnitude of HAT, a n d factors influencing propagation to be determined. This helped identify ‘HAT priority intervention areas’. The study findings suggested propagation of HAT resulted from suitability of water bodies, shrub and less-dense forest for the HAT vector, and continued exposure of human populations to these land cover classes. Overlapping of HAT vector habitat zones within built-up areas was also a cause. The study also found that HAT propagation was multidirectional, and that this may have been influenced by landscape characteristics. This novel approach can also be used in other part of Nigeria as well as adapted to investigate other diseases. In conclusion, the HAT vector habitat classification scheme is a transparent tool for policy makers for identifying vulnerable and at risk areas.

Human African Trypanosomiasis (HAT) is an infectious, vector-borne protozoal disease which is amongst the so-called neglected diseases. In 2000, at a summit of the United Nations, eight Millennium Development Goals (MDGs) were set, to be achieved by 2015. MDG 6 states “to combat HIV/AIDS, malaria & other diseases”. With just under 2 years to go before the end of 2015, HAT is still thriving in developing countries. The drugs currently used for the treatment of HAT are in short supply, have severe side effects and those used to treat late stages of the disease are very difficult to administer. The aforementioned challenges call for research into this neglected disease in order to develop new, safe and easy-to-use medicines. Naphthoquinones are a class of compounds shown to possess anti-parasitic activity, amongst a variety of other biological activities, and therefore this pharmacophore was selected for this study. The purpose of this study was to synthesise derivatives of 2,3-dichloro-1,4- naphthoquinone to be tested for anti-trypanosomal activity and thereafter conduct structureactivity relationship studies. A series of reactions were carried out using thiophenol, phenol and aniline nucleophiles to synthesise thioether (-S-), ether (-O-) and amino (-NH-) derivatives of 2,3-dichloro-1,4-naphthoquinone with various halogen or methyl substituents. Purification of the products was carried out by recrystallisation. Nuclear magnetic resonance (NMR), infra-red (IR) and high pressure liquid chromatography coupled to an electro-spray ionisation mass spectrometer (HPLC-ESI-MS) were the analytical methods used for structural confirmation of the products. There were eighteen 1,4-naphthoquinone derivatives that were successfully synthesised using ethanolic solutions. Unfortunately, attempts to synthesise 1,4-naphthoquinones in reactions involving 2-(trifluoro-methyl)aniline and 2-isopropyl-5-methylphenol were unsuccessful, presumably due to steric hindrance by the bulky ortho-substituents. Although the aims of the synthetic procedures were to obtain both mono- and disubstituted products by nucleophilic displacement of the chlorine atom(s) of 2,3-dichloro-1,4- naphthoquinone, only monosubstituted products were obtained from substitution with aniline and phenol nucleophiles. Thiol nucleophiles, however, selectively yielded disubstituted products only. Synthesised naphthoquinone derivatives were tested against Trypanosoma brucei and calculation of the EC₅₀ values from the obtained dose-response curves was carried out using the four parametric equation. All the 1,4-naphthoquinones showed a degree of potency, except compounds 1b, 3c and 3e, which had little or lack of potency. Structure-activity relationship studies (SARs and QSARs) were carried out to determine which structural features or functional group substituents of the naphthoquinone derivatives contribute or take away from the desired anti-trypanosomal activity. It was found that compounds with the best in vitro anti-trypanosomal potencies in the series of analogous 1,4-naphthoquinone derivatives had EC₅₀ values in the range 2.137 to 2.884 μM. The most potent compound in the series was 2-chloro-3-(4-(trifluoromethyl)phenylamino)-1,4- naphthoquinone 1e; but it was 142-fold less potent than the reference standard of melarsoprol.

Please read the abstract in the section 00front of this document / Thesis (PhD (Entomology))--University of Pretoria, 2005. / Zoology and Entomology / unrestricted

Cette thèse porte sur le développement d’une formulation colloïdale de diminazène (DMZ) à l’aide de nanoparticules polysaccharidiques cationiques (NP+) pour le traitement de la Trypanosomiase Africaine (TA).Nous avons étudié dans un premier temps le procédé de chargement des NP+ en DMZ base. Nous avons constaté que l’ajout de phospholipides dans la matrice des NP+ est nécessaire à l’association de DMZ. La quantité de phospholipide est d’ailleurs le facteur limitant de l’indice de saturation des NP+ en DMZ. Afin de ne pas dégrader le principe actif, lors de son chargement, le procédé choisi est le « post-loading » qui correspond à un mode opératoire en conditions douces : ajout d’une solution de DMZ dans une suspension de NP+ à cœur huileux. Nos résultats montrent que cette formulation reste stable durant 6 mois à 4°C ne libérant pas de DMZ et le protégeant de l’oxydation. Dans un second temps, nous avons évalué l’efficacité thérapeutique du DMZ formulé. Les tests in vitro sur Trypanosoma brucei brucei montrent une amélioration de l’activité trypanocide du DMZ. Les tests réalisés sur un modèle aigu de TA, ont mis en évidence que la dose efficace est équivalente au DMZ libre (3 mg/kg). / This thesis focuses on the development of a colloidal formulation of diminazene (DMZ) using cationic polysaccharide nanoparticles (NP+) for the treatment of African Trypanosomiasis. We first studied the process of DMZ loading in NP+. The addition of phospholipids in the matrix of the NP+ appeared to be necessary for the DMZ association. So, the amount of phospholipids is the limiting factor of the saturation index of NP+ with DMZ. To avoid the drug degradation during its formulation, we choose the \\\"post-loading\\\" technique which corresponds to a procedure with mild conditions: adding a DMZ solution in a suspension of NP+ containing an oily core. DMZ loaded into 70DGNP+ was found to be protected against oxidation and was stable for at least 6 months at 4°C. In a second step, we evaluated the therapeutic efficacy of formulated DMZ. In vitro tests on Trypanosoma brucei brucei showed an improvement of the DMZ trypanocidal activity. Tests on an acute model of Trypanosomiasis showed that the effective dose is equivalent to the free DMZ (3 mg / kg).

No description available.