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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
131

Aplicação de metodologia de concentração viral para detecção de astrovírus em águas ambientais / Application of viral concentration methodology for astrovirus detection in environmental waters

Guimarães, Flávia Ramos January 2007 (has links)
Made available in DSpace on 2014-12-05T18:34:09Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 101.pdf: 12703986 bytes, checksum: b3d8bcb5c201aa863f8d9d57acdab347 (MD5) Previous issue date: 2007 / Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde / A utilização e a manutenção dos recursos hídricos são temas que apresentam uma importância crescente nas discussões mundiais, devido à preocupação com a futura escassez de água dentro dos padrões de qualidade aceitáveis para o consumo. Entre os maiores problemas na utilização da água, destaca-se a sua poluição por resíduos biológicos e químicos, tornando as águas contaminadas um importante meio de transmissão de várias doenças, entre estas, as gastroenterites de etiologia viral. Este estudo teve como objetivo implementar e analisar uma metodologia para concentração de astrovirus humano (HAstV) em águas ambientais, associada a métodos moleculares de detecção, caracterização e quantificação. Foi realizado um estudo experimental com amostras de diferentes matrizes aquáticas, incluindo água de rio, mar, consumo e esgoto (efluente e afluente) para avaliação da metodologia empregada e dois estudos de campo com um total de 100 amostras ambientais (48 provenientes de uma Estação de Tratamento de Esgoto [ETE] e 52 de água de rio). Foi utilizado o método de concentração por adsorção/eluição com membrana carregada negativamente seguido de ultrafiltração associada à detecção por reação em cadeia pela polimerase precedida da transcrição reversa (RT-PCR) e a quantificação pela PCR em tempo real quantitativa (qPCR). A caracterização molecular do vírus detectado foi realizada por sequenciamento parcial do genoma da segunda fase aberta de leitura. Experimentalmente, a taxa de recuperação variou de 2,4 por cento a 65 por cento entre os diferentes tipos de amostras de água. No estudo de campo, foram detectados 16 por cento de HAstV no total de amostras ambientais, 17,3 por cento em amostras de águas de igarapés e 16,7 por cento na ETE. Uma amostra de rio foi caracterizada como HAstV-1 [...] / The use and maintenance of water resources are issues that present increasing significance in world debates, due to concern with the future scarcity of water acceptable for consuming according to quality standards. Among the major problems of water use, the more important is the pollution by biological and chemical wastes, which makes contaminated water a significant transmission route of several diseases, as gastroenteritis of viral etiology. This study aimed to implement and analyze a methodology for human astrovirus (HAstV) concentration from environmental waters, associated with molecular methods of detection, characterization and quantification. An experimental research was performed with different aquatic sources samples, including river water, seawater, potable water and sewage (inflow and outflow) to evaluate the methodology used, and two field’s research with a total of 100 environmental samples (48 from a Sewage Treatment Plant [STP] and 52 from river water). A method of concentration by adsorption/elution into an electronegative membrane followed by ultrafiltration combined to reverse transcriptase – polymerase chain reaction (RT-PCR) and real time PCR (qPCR) quantification was utilized. The molecular characterization of the detected virus was performed by genome partial sequencing of the second open reading frame (ORF-2). Experimentally, the recovery rate ranged from 2.4% to 65% among the different matrices of water samples. In field research, 16% of HAstV were detected of the total environmental samples, 17,3% from river water samples, and 16,7% from STP. One river water sample was characterized as HAstV-1. The qPCR method exhibited an 18 copies/reaction sensibility and the comparative analysis of the results showed a low detection (2%) in comparison with RT-PCR (15%). The association of the methods used proved the presence of HAstV in environmental waters, being an important tool for water quality assessment, for viral particle removal efficiency assessment in different treatment water methods and to elucidate the epidemiology HAstV waterborne outbreaks
132

Avaliação de um protocolo visando o diagnóstico rápido dos enterovírus associados a casos de paralisia flácida aguda / Evaluation of a protocol for the rapid diagnosis of enterovirus associated with acute flaccid paralysis cases

Dias, Aline Peçanha Muzy^ract January 2008 (has links)
Made available in DSpace on 2014-07-28T18:10:50Z (GMT). No. of bitstreams: 2 license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) 97.pdf: 1747812 bytes, checksum: ac9891f962a8dc55e948eb9245ec6dc5 (MD5) Previous issue date: 2008 / Made available in DSpace on 2014-12-22T16:56:35Z (GMT). No. of bitstreams: 2 97.pdf: 1747812 bytes, checksum: ac9891f962a8dc55e948eb9245ec6dc5 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde / Os enterovírus estão entre os mais comuns vírus humanos e são de grande interesse devido à ampla variedade de infecções que podem causar. A vigilância das Paralisias Flácidas Agudas (PFAs) e o diagnóstico laboratorial dos enterovírus são partes críticas da iniciativa da Organização Mundial de Saúde para erradicação mundial da poliomielite, assim como a necessidade de disponibilizar técnicas rápida para o diagnóstico diferencial destes vírus. A caracterização dos enterovírus é importante para a investigação da diversidade de vírus co-circulantes, para determinar a correlação entre dados celulares e bioquímicos durante a infecção,para relacionar o tipo de sintoma clínico com o sorotipo enteroviral, incluindo a investigação de vias de transmissão de enterovírus durante épocas de surtos. Além disso, a caracterização dos enterovírus é de extrema relevância para distinguir as infecções provocadas pelos Poliovirus dos enterovírus não-pólio no contexto do Programa de Erradicação da Poliomielite da OMS. O presente estudo teve como objetivo principal identificar, através da técnica de RT-PCR e seqüenciamento nucleotídico, a presença de enterovírus diretamente das amostras de primeira passagem de cultura celular a fim de diminuir o custo e o tempo de liberação do diagnóstico. Para isso, foram analisadas 221 amostras de casos suspeitos de PFA, inoculadas em primeira passagem de cultura de células RD. Destas, 17 foram positivas para enterovírus. A comparação da técnica com a indicada pela OMS mostrou alta sensibilidade e especificidade, indicando que a nova metodologia pode ser seguramente empregada como forma de garantia de um diagnóstico mais rápido. / The enterovirus are among the most common human viruses, and are of great interest because of the wide variety of infections that can cause. The surveillance of Acute Flaccid Paralysis (AFP) and laboratory diagnosis of enterovirus are critical parts of the initiative of the World Health Organization (WHO) to eradicate polio worldwide, as well as the availability of rapid completion of techniques are needed for the differential diagnosis of these viruses. The characterization of enterovirus is important for the research of the diversity of virus co-circulating, to determine the correlation between cellular and biochemical data during infection, relate to the type of clinical symptoms with the serotype enteroviral, including investigation of routes of transmission of enterovirus during times of outbreaks. Moreover, the characterization of enterovirus is of extreme importance to distinguish Poliovirus infections caused by the enterovirus non pólio in the context of the Program for the Eradication of Poliomyelitis of WHO. The aim of this study is to identify, through RT-PCR and nucleotide sequencing, the presence of enterovírus genome directly from first passage of cell culture in order to reduce the cost and time of release of diagnosis. For that, were analyzed 221 samples of suspected cases of FAP, inoculated in first passage of RD cell culture. Seventeen samples were positive for enterovirus. The comparison this technique with the indicated by the WHO showed high sensitivity and specificity, indicating that the new method can be safely employed as a way of ensuring a faster diagnosis.
133

Avaliação do RNA mensageiro (RNAm) do Mycobacterium tuberculosis como marcador de cura em pacientes com tuberculose pulmonar / Assessment of messenger RNA (mRNA) of Mycobacterium tuberculosis as a marker of cure in patients with pulmonary tuberculosis

Montenegro, Rosana de Albuquerque January 2012 (has links)
Made available in DSpace on 2015-06-12T13:55:09Z (GMT). No. of bitstreams: 2 462.pdf: 1936396 bytes, checksum: 04bba025d07d06eee03a3b5eb14ad34e (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Centro de Pesquisas Aggeu Magalhães. Recife, PE, Brasil / A tuberculose (TB) é um dos grandes problemas de saúde pública mundial devido às suas altas taxas de morbimortalidade e índices de transmissão, apesar de existir tratamento e medidas eficazes de controle da doença. O diagnóstico precoce associado a uma terapêutica adequada é essencial para a eficácia dos programas públicos de controle. As técnicas diagnósticas, baciloscopia e cultura, utilizadas de rotina para a detecção do Mycobacterium tuberculosis em amostras clínicas são falhas em sensibilidade e na demora da obtenção dos resultados, respectivamente. A cultura é considerada o método padrão-ouro para avaliar a viabilidade do bacilo em pacientes com tuberculose em vigência de tratamento específico, porém, por ser laboriosa e necessitar de pelo menos 4 semanas para o crescimento do bacilo, dificulta bastante o monitoramento clínico e a resposta do paciente às drogas tuberculostáticas. Neste contexto, os métodos moleculares vêm sendo desenvolvidos com destaque para a tecnologia da reação em cadeia da polimerase (PCR) destacando a Transcrição Reversa seguida de PCR quantitativa em tempo real (RT-qPCR) utilizando o RNA mensageiro que expressa bem a viabilidade bacilar. Neste trabalho foi analisado o desempenho da RT-qPCR utilizando como alvo o gene 85B do Mycobacterium tuberculosis na detecção e resposta ao tratamento específico da tuberculose pulmonar. Foi realizada uma padronização com diferentes concentrações dos primers e sonda desenhados por Desjardin et al, (1999). Construiu-se uma curva padrão de DNA plasmidial gerando um limite de detecção de 10pg/1x10 e-6 (7x10 e7 cópias/reação), epson = 106, R2= 0,98 por cento, e slope= -3,18. O sistema foi avaliado em 98 pacientes com suspeita de TB pulmonar apresentando uma sensibilidade de 91,07 por cento e especificidade de 97,61 por cento, quando comparado à cultura. Em 56 pacientes com tuberculose pulmonar acompanhados durante 30 dias de tratamento específico verificou-se que a RT-qPCR e a cultura apresentaram uma excelente concordância, tendo sido observado um declínio de bacilos viáveis nos dias 15 e 30 após o início da terapêutica na maioria deles. Desta forma, os resultados encontrados sugerem que a RT-qPCR é uma ferramenta que pode ser utilizada no monitoramento clínico e terapêutico, como sinalizador de resistência bacteriana e indicador do período de transmissibilidade do M. tuberculosis em pacientes com TB pulmonar submetidos a tratamento específico
134

Cisteína-proteinases em promastigotas de Leishmania (Viannia) braziliensis

Rebello, Karina Mastropasqua January 2008 (has links)
Made available in DSpace on 2016-04-04T12:35:28Z (GMT). No. of bitstreams: 2 karina_rebello_ioc_mest_2008.pdf: 6872283 bytes, checksum: a0cb112c96e6862c0ff341afeb28dbf5 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / No presente trabalho foram detectadas cisteína-proteinases (CPs) em promastigotas infectivas de Leishmania (Viannia). braziliensis. A estratégia de purificação consistiu na associação do método de extração por Triton X-114 com cromatografia em coluna de Concanavalina A-Sepharose, seguida por outra de DEAE-Sephacel. No ensaio das cromatografias, observamos um pico majoritário de atividade enzimática na presença do substrato pEFLpNan (165 x 10³² \03BCM de pNan/minuto) para cerca de 10¹0 parasitas, coincidentes com o pico majoritário da proteína eluído da coluna de troca iônica. A análise por SDS-PAGE do material eluído da coluna de troca iônica mostrou quatro principais bandas de proteínas com massas moleculares relativas de 63, 43, 30 e 27 kDa. Os ensaios da atividade enzimática após eletroforese mostraram que as bandas de 63 kDa e 43 kDa, hidrolisam substratos como gelatina em pH 7,0 e são sensíveis à presença de E-64. Além disso, as duas enzimas são capazes de hidrolisar o substrato pEFLpNan: 63 kDa (2,2 ± 0,3 \03BCM de pNan/minuto) e 43 kDa (0,05 ± 0,2 \03BCM de pNan/minuto), e são inibidas por 10\03BCM E-64 (47 % e 36 % respectivamente). Os ensaios de reconhecimento imunológico utilizando um anti-soro policlonal específico contra cisteína-proteinase B [anti-CPB de L. (L.) mexicana] revelaram que as enzimas de 63 kDa são reconhecidas por este anti-soro. Os experimentos de aglutinação, citometria de fluxo e imunocitoquímica utilizando esse mesmo antisoro revelaram que homólogos de CPBs estão localizados na superfície da membrana de promastigotas. Além disso, a incubação dos promastigotas com fosfolipase C (PLC) reduziu o número de células positivas pra os homólogos de CPB. Os anti-soros anti-CRD (cross reactive determinat) e anti-CPB reconhecem bandas de 63kDa e 43 kDa do sobrenadante das células tratadas com PLC em ensaios de immunoblotting sugerindo que isoformas destas proteínas são ancoradas por glicosilfostatidilinositol (GP (GPI) à membrana plasmática. Também observamos que os homólogos de CPBs são presos a membrana por âncora GPI e se concentram em plataformas lipídicas. Nós observamos que as proteínas homólogas a CPB não permanecem estáveis na superfície da membrana quando os parasitas são mantidos em culturas sucessivas, assim como a atividade enzimática total sobre o substrato pEFLpNan é alterada. Mostramos ainda através da técnica RT-PCR em tempo real um aumento da transcrição de cpb de L. (V.) braziliensis quando os parasitas foram submetidos a culturas sucessivas. De uma forma geral os dados apresentados suportam a hipótese de que o parasita estudado apresentam CPs de membrana ativas, além de homólogos de CPB intracelulares. / It was detected cysteine-pro teinases (CPs) in infective Leishmania (Viannia) braziliensis promastigotes . The purification strategy c onsisted of an association of Triton X-114 extraction method with chromatography in Concanavalin A-Sepharose column, followed by chromatography in DEAE-Sephacell column. In the assay pf chromatographic fractions, we observed a peak of enzymatic activity against the pEFLpNan substrate (165 x 10 -32 μM of pNan/minute) in over 10 10 parasites, coincident with the ma jor protein peak eluted from the column. SDS-PAGE analysis of the material eluted from the ionic exchange column showed four main protein bands with relative molecular mass of 63 , 43, 30 and 27 kDa. Gelatin-SDS-PAGE assays indicated that the 43kDa and the 63kDa bands can hydrolyze gelatin at neutral pH and are sensitive to E-64. Also, both enzymes can hydrolyze pEFLpNan substrate: 63 kDa (2,2 ± 0,3 μM of pNan/minute) and 43 kDa (0,05 ± 0,2 μM of pNan/minute) bei ng both inhibited by E-64 (47 % and 36 % inhibition, respectively) . Immunological recognition assays , with a specific polyclonal antibody against CPB from L. (L.) mexicana , showed that bands of 63 kDa and 43 kDa are recognized in the fractions of the ionic exchange column. Aggl utination, flow cytometry and immunocytochemistry assays performed with an ti-CPB antiserum revealed that homologous of CPB are located on the promastigote membrane surface. Moreover, the incubation of promastigotes with phospholipase C reduced th e number of CPBs homologues-positive cells. Both anti-cross-reacting determinant (CRD) a nd anti-CPB antisera recognized 63kDa and 43kDa bands in the supernatant of phospholipase C-treat ed cells, suggesting that isoforms of these proteins are attached to the plasma membra ne by glycosylphosphatidylinositol (GPI)-anchors. Also, our data suggest that GPI-anchored CPBs are present in the detergent - resistant lipid rafts. We observed that the CPB homologues do not remain stable on the membrane surface when the parasites are maintained under successive cultur es; also, the total enzymatic activity over the substrate pEFLpNan is altered. We add itionally showed by real-time RT-PCR that L. (V). braziliensis cpb genes are active and their relative expression is increased throughout the successive cultures. Thus, the presented data support the hypothesis of that studied parasite presents CPs of membrane active, beyond homologous of intracellular CPB.
135

Structure-Function Study of Telomerase RNA from Evolutionary Disparate Species: Remarkable Divergence in Gross Architecture with the Preservation of Critical Universal Structural Elements

January 2015 (has links)
abstract: Telomerase enzyme is a truly remarkable enzyme specialized for the addition of short, highly repetitive DNA sequences onto linear eukaryotic chromosome ends. The telomerase enzyme functions as a ribonucleoprotein, minimally composed of the highly conserved catalytic telomerase reverse transcriptase and essential telomerase RNA component containing an internalized short template region within the vastly larger non-coding RNA. Even among closely related groups of species, telomerase RNA is astonishingly divergent in sequence, length, and secondary structure. This massive disparity is highly prohibitive for telomerase RNA identification from previously unexplored groups of species, which is fundamental for secondary structure determination. Combined biochemical enrichment and computational screening methods were employed for the discovery of numerous telomerase RNAs from the poorly characterized echinoderm lineage. This resulted in the revelation that--while closely related to the vertebrate lineage and grossly resembling vertebrate telomerase RNA--the echinoderm telomerase RNA central domain varies extensively in structure and sequence, diverging even within echinoderms amongst sea urchins and brittle stars. Furthermore, the origins of telomerase RNA within the eukaryotic lineage have remained a persistent mystery. The ancient Trypanosoma telomerase RNA was previously identified, however, a functionally verified secondary structure remained elusive. Synthetic Trypanosoma telomerase was generated for molecular dissection of Trypanosoma telomerase RNA revealing two RNA domains functionally equivalent to those found in known telomerase RNAs, yet structurally distinct. This work demonstrates that telomerase RNA is uncommonly divergent in gross architecture, while retaining critical universal elements. / Dissertation/Thesis / Doctoral Dissertation Molecular and Cellular Biology 2015
136

Caracterização bioquimica e molecular do componente transcriptase reversa da telomerase de Leishmania spp / Biochemical and molecular characterization of the Leishmania spp. telomerase reverse transcriptase component

Giardini, Miriam Aparecida 14 June 2007 (has links)
Orientador: Maria Isabel Nogueira Cano / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T06:46:56Z (GMT). No. of bitstreams: 1 Giardini_MiriamAparecida_D.pdf: 16478216 bytes, checksum: 881eff76c52bbb67a22537e86deba896 (MD5) Previous issue date: 2007 / Resumo: Telômeros são complexos DNA-proteínas que protegem os cromossomos eucarióticos da degradação, garantindo estabilidade genômica. As seqüências teloméricas são ricas em G e apresentam uma protrusão 3¿ simples-fita que se estende em direção ao terminal cromossômico. Em Leishmania, os telômeros são compostos pela seqüência repetida 5¿-TTAGGG-3¿ e são replicados pela telomerase, a principal responsável pela manutenção dos terminais cromossômicos em eucariotos. Além de replicar os telômeros, o complexo holoenzimático da telomerase, composto pela transcriptase reversa da telomerase (TERT), pelo RNA da telomerase (TER) e por proteínas associadas, também atua como parte de um complexo de ordem maior que protege os terminais teloméricos. O entendimento do mecanismo de regulação da manutenção telomérica será de grande valor científico e poderá levar ao descobrimento de algum alvo potencial para o desenvolvimento de novas drogas anti-leishmania. Com esse objetivo, identificamos, clonamos e caracterizamos o gene que codifica o componente TERT em Leishmania spp.. O alinhamento múltiplo das seqüências através do programa ClustalW demonstrou que as telomerases de Leishmania apresentam muito mais homologia entre si do que com as proteínas de outros kinetoplastídeos e eucariotos. Experimentos de caracterização indicaram que a seqüência putativa do gene da telomerase de Leishmania localiza-se provavelmente em cópia única nos maiores cromossomos. Um único transcrito de RNA mensageiro foi encontrado nos promastigotas. Análises filogenéticas sugeriram que a telomerase de Leishmania pode representar uma ligação entre os mais antigos e os mais novos ramos das telomerases. Além disso, proteínas recombinantes foram expressas em sistema bacteriano, tornando possível a produção de anticorpos policlonais em coelhos. Experimentos de ¿Western blotting¿ e imunoprecipitação de cromatina indicaram que o anticorpo foi capaz de reconhecer a proteína nativa e que a telomerase de L. amazonensis interage in vivo com a seqüência telomérica rica em G. A atividade de telomerase de L. amazonensis foi purificada utilizando-se uma combinação de colunas cromatográficas. Testou-se a atividade enzimática em cada passo da purificação utilizando-se o ensaio ¿Two-tube TRAP¿. Os resultados mostraram que a atividade enzimática é encontrada nas frações purificadas pelas cromatografias de troca iônica, de afinidade por Heparina e de gel filtração. A atividade foi altamente enriquecida após a purificação por afinidade utilizando um oligonucleotídeo de DNA telomérico rico em G. Quando foi utilizado um oligorribonucleotídeo 2¿O-metil complementar à putativa seqüência molde do TER de Leishmania como ligante na cromatografia de afinidade, pouca ou nenhuma atividade enzimática foi eluída da resina, sugerindo que a interação entre a telomerase de L. amazonensis e este oligorribonucleotídeo é tão forte que não permite sua dissociação nas condições de eluição gentis necessárias para manter a atividade enzimática. Formas procíclicas de Trypanosoma brucei foram utilizadas para a construção do sistema ¿PTP-tagging¿, no intuito de futuramente purificar o complexo holoenzimático da telomerase. Em paralelo, ensaios de ¿primer extension¿ foram padronizados e identificou-se uma seqüência candidata ao gene do RNA da telomerase de T. brucei. Também foi identificada e clonada em L. amazonensis, uma seqüência homóloga à PinX1 humana, descrita como uma proteína que interage diretamente com a TERT humana e considerada um inibidor natural da atividade de telomerase / Abstract: Telomeres are protein-DNA complexes that protect linear chromosomes from degradation, providing genomic stability. The telomeric sequences are G-rich and contain a 3¿ single-stranded region that protrudes toward the chromosome end. In Leishmania, the telomeric DNA is composed by the conserved 5¿-TTAGGG-3¿ repeated sequence and it is replicated by telomerase. Telomerase is responsible for maintaining chromosome ends in most eucaryotes by adding new telomeric sequences to the G-rich strand. Besides replicating telomeres, the telomerase holoenzyme complex, composed by the reverse transcriptase component (TERT), the telomerase RNA (TER) and associated proteins, also works as part of the higher order complex that protects telomeric ends. Understanding the regulation of the telomeric maintainance mechanism may allow the discovery of potential targets to the development of new antileishmania drugs. Therefore, we identified, cloned and characterized the TERT gene in Leishmania spp.. A ClustalW multiple-sequence alignment demonstrated that the Leishmania telomerases show greater homology with each other than with the proteins of other kinetoplastids and eukaryotes. Characterization experiments indicated that the putative Leishmania TERT gene was probably located in single copy at the largest chromosomes. A single messenger RNA transcript was found in promastigotes. Phylogenetic analysis suggested that Leishmania telomerase might represent a liaison between the oldest and the newest branches of telomerases. Besides that, recombinant proteins were expressed in bacterial system, allowing production of anti-LaTERT polyclonal serum in rabbits. Western blotting and chromatin immunoprecipitation assays indicated that the anti-LaTERT serum was able to recognize a native protein in nuclear and total extracts of the parasite and that L. amazonensis telomerase interacts in vivo with the G-richtelomeric sequence. We have also purified the L. amazonensis telomerase activity in order to better understand its biochemical features. Protein extracts of L. amazonensis containing telomerase activity were purified using combined chromatographic columns. Enzyme activity was tested in each purification step using the ¿Two-tube TRAP¿ assay. The results showed that enzyme activity is found in fractions purified by ion exchange (DEAE), Heparin affinity and gel filtration chromatographic methods. The activity was greatly enriched after affinity purification using a G rich telomeric DNA oligonucleotide as the ligand. When a 2¿O-methyl oligoribonucleotide complementary to the putative L. amazonensis TER template was used as a ligand in the affinity purification, little or no enzyme activity was eluted from resin, suggesting that the interaction between L. amazonensis telomerase and this oligoribonucleotide is too strong that disables its dissociation under the gentle elution conditions necessary to maintain enzyme activity. In order to identify the telomerase holoenzyme components, procyclic forms of Trypanosoma brucei were used to construct the PTP-tagging system. ¿Primer extension¿ reactions were also done in order to isolate and sequence an RNA candidate for the telomerase RNA gene in T. brucei. In addition, we have cloned a L. amazonensis homologue of the human PinX1 protein, previously known as a hTERT-interacting factor and as a potent telomerase inhibitor / Doutorado / Genetica de Microorganismos / Doutor em Genetica e Biologia Molecular
137

Immunosuppressive and angiogenic cytokine profile associated with Bartonella bacilliformis infection in post-outbreak and endemic areas of Carrion's disease in Peru

Pons, Maria J., Gomes, Cláudia, Aguilar, Ruth, Barrios, Diana, Aguilar-Luis, Miguel Angel, Ruiz, Joaquim, Dobaño, Carlota, del Valle-Mendoza, Juana, Moncunill, Gemma 19 June 2017 (has links)
Analysis of immune responses in Bartonella bacilliformis carriers are needed to understand acquisition of immunity to Carrion’s disease and may allow identifying biomarkers associated with bacterial infection and disease phases. Serum samples from 144 healthy subjects from 5 villages in the North of Peru collected in 2014 were analyzed. Four villages had a Carrion’s disease outbreak in 2013, and the other is a traditionally endemic area. Thirty cytokines, chemokines and growth factors were determined in sera by fluorescent bead-based quantitative suspension array technology, and analyzed in relation to available data on bacteremia quantified by RT-PCR, and IgM and IgG levels measured by ELISA against B. bacilliformis lysates. The presence of bacteremia was associated with low concentrations of HGF (p = 0.005), IL-15 (p = 0.002), IL-6 (p = 0.05), IP-10 (p = 0.008), MIG (p = 0.03) and MIP-1α (p = 0.03). In multi-marker analysis, the same and further TH1-related and pro-inflammatory biomarkers were inversely associated with infection, whereas angiogenic chemokines and IL-10 were positively associated. Only EGF and eotaxin showed a moderate positive correlation with bacteremia. IgM seropositivity, which reflects a recent acute infection, was associated with lower levels of eotaxin (p = 0.05), IL-6 (p = 0.001), and VEGF (p = 0.03). Only GM-CSF and IL-10 concentrations were positively associated with higher levels of IgM (p = 0.01 and p = 0.007). Additionally, IgG seropositivity and levels were associated with high levels of angiogenic markers VEGF (p = 0.047) and eotaxin (p = 0.006), respectively. Our findings suggest that B. bacilliformis infection causes immunosuppression, led in part by overproduction of IL-10. This immunosuppression probably contributes to the chronicity of asymptomatic infections favoring B. bacilliformis persistence in the host, allowing the subsequent transmission to the vector. In addition, angiogenic markers associated with bacteremia and IgG levels may be related to the induction of endothelial cell proliferation in cutaneous lesions during chronic infections, being possible candidate biomarkers of asymptomatic infections.
138

Xenobiotic-metabolizing cytochrome P450 enzymes in human lung

Hukkanen, J. (Janne) 21 December 2000 (has links)
Abstract The cytochrome P450 (CYP) enzyme system in human lung is an essential component in the pulmonary carcinogenicity of several inhaled xenobiotic compounds. The aim of this study was to elucidate the expression and regulation of xenobiotic-metabolizing CYP enzymes in human lung. To evaluate which of the two is a better surrogate cell model for lung tissue, the expression patterns of CYP enzymes in alveolar macrophages and peripheral blood lymphocytes were clarified by reverse transcriptase-polymerase chain reaction (RT-PCR) and compared to the expression in lung tissue. The pattern of CYP expression in alveolar macrophages was found to closely resemble the expression pattern in human lung tissue, while the pattern in lymphocytes was markedly different. The expression of CYP2B6, CYP2C, CYP3A5, and CYP4B1 mRNAs in alveolar macrophages was demonstrated for the first time. To facilitate mechanistic studies on human pulmonary CYP induction, the A549 lung adenocarcinoma cell line was characterized by RT-PCR, and the CYP expression pattern was found to compare reasonably well to human lung epithelial cells. The induction of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) behaved as predicted, and CYP1B1 and CYP3A5 were also inducible by TCDD and dexamethasone, respectively. TCDD elevated the level of CYP1A1 mRNA (56-fold), while the induction of CYP1B1 mRNA was more modest (2.5-fold). The tyrosine kinase inhibitor genistein and the protein kinase C inhibitor staurosporine blocked CYP1A1 induction by TCDD, but did not affect CYP1B1 induction. The serine/threonine protein phosphatase inhibitor calyculin A and okadaic acid enhanced CYP1B1 induction slightly, but did not alter CYP1A1 induction. The expression of CYP3A forms in human pulmonary tissues was studied with RT-PCR and immunohistochemistry, and both methods established CYP3A5 as the main CYP3A form. CYP3A4 was expressed in only about 20% of the cases. In A549 cells, CYP3A5 was induced about 4-fold by the glucocorticoids budesonide, beclomethasone dipropionate, and dexamethasone. Maximal induction was achieved by concentrations as low as ~100 nM, suggesting that CYP3A5 could be induced in vivo in patients using inhaled glucocorticoids. However, there were no differences in CYP3A5 expression in alveolar macrophages in current glucocorticoid users, ex-users, and non-users. Cigarette smoking had a marked decreasing effect on CYP3A5 levels in alveolar macrophages. The presence and possible induction of CYP3A5 by glucocorticoids in human lung could have consequences for the maintenance of physiological steroid hormone balance in lung and the individual susceptibility to lung cancer of patients using glucocorticoids.
139

Studies on the thermostabilization of reverse transcriptases from Moloney murine leukemia virus and avian myeloblastosis virus / モロニーマウス白血病ウイルス逆転写酵素およびトリ骨髄芽球症ウイルス逆転写酵素の耐熱化に関する研究

Konishi, Atsushi 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19016号 / 農博第2094号 / 新制||農||1029(附属図書館) / 学位論文||H27||N4898(農学部図書室) / 31967 / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 保川 清, 教授 河田 照雄, 教授 谷 史人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
140

Coevolution of epitopes in HIV-1 pre-integration complex proteins: protein-protein interaction insights

Hetti Arachchilage, Madara Dilhani 18 July 2018 (has links)
No description available.

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