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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.
121

Characterization of mechanisms involved in rickettsia pathogenicity

Vellaiswamy, Manohari 23 November 2011 (has links) (PDF)
Les rickettsies sont de petites bactéries à Gram-négatif associées à différentes espèces d'arthropodes. Leur nature intracellulaire stricte a longtemps été un obstacle à la compréhension des mécanismes moléculaires responsables de leur pathogénicité qui restent mal connus. L'adhésion bactérienne, qui est une étape clef de l'invasion des tissus de l'hôte, met en jeu les protéines rOmpA et rOmpB (rickettsial outer membrane proteins), identifiées depuis longtemps comme des antigènes de surface majeurs des rickettsies. L'objectif de cette thèse a été de caractériser une autre adhésine potentielle de Rickettsia prowazekii récemment identifiée, soit Adr2. La stratégie mise en œuvre a été basée sur la production d'anticorps monoclonaux spécifiques de cette protéine, dont une forme recombinante a été exprimée. Cet outil a permis, non seulement de localiser Adr2 à la surface des rickettsies, mais aussi d'apporter la preuve de son rôle dans le phénomène invasif puisque les anticorps anti-Adr2 diminuent significativement la cytotoxicité des rickettsies sur les cellules épithéliales. Un autre aspect de la pathogénicité que nous avons abordé concerne la mobilité des rickettsies du groupe boutonneux, fonction attribuée à la protéine RickA lorsque ce travail a été initié. La résolution des images obtenues par immunofluorescence, ou par microscopie électronique après marquage immunogold, montrent que l'expression de RickA est non-polarisée et répartie sur la surface entière de Rickettsia conorii. Enfin, plusieurs protéines recombinantes ont été utilisées dans des tests de screening sérologiques avec des sérums de patients infectés par diverses rickettsies, avec des résultats encourageants. L'ensemble de ces résultats contribue à une meilleure connaissance de la pathogénicité des bactéries du genre Rickettsia.
122

Causes of Substitution Frequency Variation in Pathogenic Bacteria

Davids, Wagied January 2005 (has links)
<p>Estimating substitution frequencies at sites that influence (Ka) and do not influence (Ks) the amino acid sequence is important for understanding the dynamics of molecular sequence evolution and the selective pressures that have shaped genetic variation. </p><p>The aim of this work was to gain a deeper understanding of the driving forces of substitution frequency variation in human pathogens. <i>Rickettsia prowazekii</i>, the causative agent of epidemic typhus and <i>Helicobacter pylori</i>, which has been implicated in gastric diseases were used as model systems. A specific focus was on the evolution of orphan genes in <i>Rickettsia</i>. Additionally, adaptive sequence evolution and factors influencing protein evolutionary rates in <i>H. pylori</i> were studied.</p><p>The comparative sequence analyses of orphan genes using Typhus Group (TG) and Spotted Fever Group (SFG) <i>Rickettsia</i>, indicate that orphan genes in the SFG correspond to pseudogenes in the TG and that pseudogenes in the SFG correspond to extensively degraded gene remnants in the TG. The analysis also showed that ancestral gene sequences could be reconstructed from extant gene remnants of closely related species. The studies of split genes in <i>R. conorii</i> indicate that many of the small fragmented ORFs are probably pseudogenes. Analysis of the <i>H. pylori </i>carbamoyl phosphate synthetase provided an opportunity to understand natural selection acting on a protein undergoing adaptive evolution. Factors such as network properties, protein-protein interactions, gene essentiality and chromosomal position on protein evolutionary rates in <i>H. pylori</i> were studied, of which antigenicity and gene location were identified as the strongest factors. </p><p>In conclusion, high Ka/Ks ratios in human pathogens may reflect either adaptive sequence evolution or gene deterioration. Distinguishing between the two is an important task in molecular evolution and also of great relevance for medical microbiology and functional genomics research.</p>
123

Causes of Substitution Frequency Variation in Pathogenic Bacteria

Davids, Wagied January 2005 (has links)
Estimating substitution frequencies at sites that influence (Ka) and do not influence (Ks) the amino acid sequence is important for understanding the dynamics of molecular sequence evolution and the selective pressures that have shaped genetic variation. The aim of this work was to gain a deeper understanding of the driving forces of substitution frequency variation in human pathogens. Rickettsia prowazekii, the causative agent of epidemic typhus and Helicobacter pylori, which has been implicated in gastric diseases were used as model systems. A specific focus was on the evolution of orphan genes in Rickettsia. Additionally, adaptive sequence evolution and factors influencing protein evolutionary rates in H. pylori were studied. The comparative sequence analyses of orphan genes using Typhus Group (TG) and Spotted Fever Group (SFG) Rickettsia, indicate that orphan genes in the SFG correspond to pseudogenes in the TG and that pseudogenes in the SFG correspond to extensively degraded gene remnants in the TG. The analysis also showed that ancestral gene sequences could be reconstructed from extant gene remnants of closely related species. The studies of split genes in R. conorii indicate that many of the small fragmented ORFs are probably pseudogenes. Analysis of the H. pylori carbamoyl phosphate synthetase provided an opportunity to understand natural selection acting on a protein undergoing adaptive evolution. Factors such as network properties, protein-protein interactions, gene essentiality and chromosomal position on protein evolutionary rates in H. pylori were studied, of which antigenicity and gene location were identified as the strongest factors. In conclusion, high Ka/Ks ratios in human pathogens may reflect either adaptive sequence evolution or gene deterioration. Distinguishing between the two is an important task in molecular evolution and also of great relevance for medical microbiology and functional genomics research.
124

Detection and quantification of Borrelia lonestari and a rickettsial endosymbiont in Amblyomma americanum ticks from southern Indiana using real-time PCR

Sullivan, Bridget E. January 2005 (has links)
Amblyomma americanum, the lone star tick, is an indigenous tick species in southern Indiana that harbors a diverse group of pathogenic and nonpathogenic microorganisms, including Borrelia lonestari, the putative agent for the southern tick associated rash illness (START) and a spotted fever group rickettsial endosymbiont. The purpose of this study was to implement the real-time polymerase chain reaction (real-time PCR) as a molecular technique to examine the microbial diversity in A. americanum ticks by estimating abundances of different microorgansisms. A SYBR Green real-time PCR assay was designed to detect and quantify B. lonestari in A. americanum ticks, and a previously published TaqMan real-time PCR assay, designed to detect (not quantify) Rickettsia species in ticks, was validated for the detection and quantification of the spotted fever group rickettsial endosymbiont in A. americanum ticks. Many pitfalls associated with real-time PCR were experienced in this study, such as difficulties in assay design and problems with contamination, and appropriate modifications are recommended to laboratories routinely performing real-time PCR. / Department of Biology
125

Detection and quantification of Rickettsia amblyommii, Ehrlichia chaffeensis, and Borrelia lonestari in adult Amblyomma americanum ticks from southern Indiana

Dearth, Stephanie M. January 2007 (has links)
Amblyomma americanum is a hard tick species found in southern Indiana. Once a notorious pest to humans and livestock, A. americanum has now taken on a role as vector to pathogenic organisms. This study aimed to detect and quantify three microbes in A. americanum: Rickettsia amblyommii, Ehrlichia chaffeensis, and Borrelia lonestari. A primary objective of this study was to determine microbial interaction within a single A. americanum tick through quantification of each microbe within a co-infected tick. A second objective was to determine the density of R. amblyommii within the salivary glands of A. americanum ticks. Infection rates were 44%, 1%, and 0% for R. amblyommii, E. chaffeensis, and B. lonestari respectively. This study found no co-infected ticks, therefore no microbial interaction was determined. This study also found multiple drawbacks with utilizing quantitative real-time PCR to determine the density of R. amblyommii within the salivary glands of A. americanum ticks. / Department of Biology
126

Patogeny v klíšťatech získaných ze psů a koček v Českých Budějovicích a okolí

HÁJKOVÁ, Hana January 2017 (has links)
During a period of 3 years, from March to July 2014, 2015 and 2016, ticks were collected from dogs and cats in shelter facilities for abandon animals in Česke Budejovice, South Bohemia. In total, 343 ticks were found on 106 pets: 67 domestic dogs and 39 cats. All collected ticks, that were identified as Ixodes ricinus and Ixodes hexagonus, were tested for the presence of spirochetes from Borrelia burgdorferi sensu lato (s.l.) complex, Rickettsia spp., Anaplasma spp, and Babesia spp using conventional PCR and nested PCR. Identification of pathogens was done by following sequencing of amplicons. Out of all tested ticks, 49,56% were proved to be infected at least with one pathogen. Co-infection of at least two different pathogens was determined in 18 ticks (5,2%). The aim of the present study was to estimate the role of accompanying animals (cats and dogs) in the circulation of ticks and tick-borne pathogens, to determine the frequency of pathogenic infections in dog and cat associated ticks, to evaluate the current risk of infection for dogs and cats, with respect torisk forhumans living in the area of České Budějovice.
127

Estudo molecular da Febre Maculosa Brasileira no diagnóstico diferencial com Dengue no Estado do Rio de Janeiro durante o período de 2010 a 2011

Monteiro, Kerla Joeline Lima January 2014 (has links)
Made available in DSpace on 2015-10-21T12:25:08Z (GMT). No. of bitstreams: 2 kerla_monteiro_ioc_mest_2014.pdf: 3052462 bytes, checksum: 30bf40773ca5991e3c3f964f2d53fca8 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2015-06-10 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / Doenças febris agudas são comuns e frequentemente associadas com agentes infecciosos em países tropicais como o Brasil. Com manifestações clínicas inespecíficas de difícil diferenciação com uma série de doenças endêmicas como dengue, leptospirose e outras doenças fatais, a febre maculosa brasileira (FMB) raramente tem sido considerada no diagnóstico, fato que, com o consequente retardo no tratamento antimicrobiano específico, tem determinado a elevada letalidade frequentemente observada em nosso país. A dengue é uma das doenças infecciosas mais importantes e frequentes no Brasil, onde epidemias são relatadas periodicamente no estado do Rio de Janeiro. Durante surtos de dengue, a possibilidade de erros no diagnóstico, devido à semelhança clínica, é uma realidade e a FMB deve ser considerada no diagnóstico diferencial de pacientes com febre, cefaleia e exantema. Neste contexto, considerando a hipótese de que a FMB, uma zoonose negligenciada transmitida por carrapatos, por falta de suspeita clínica, possa não ter sido identificada durante o surto de dengue ocorrido nos anos de 2010-2011, um estudo retrospectivo foi realizado com base em dados secundários e em amostras acondicionadas em laboratório de saúde pública Amostras de sangue de pacientes com suspeita de dengue, mas que foram descartadas sorologicamente para dengue durante o período de janeiro de 2010 a junho de 2011, no estado do Rio de Janeiro, foram submetidas à amplificação por PCR usando primers rickettsianos específicos para genes gltA e rOmpA. A partir dos critérios de elegibilidade preconizados, somente 319 amostras, dos 4.343 casos identificados, foram submetidas à pesquisa de FMB. Rickettsia rickettsii foi identificada em dois casos fatais no município do Rio de Janeiro e ambos pacientes apresentavam quadro clínico inespecífico sem exantema, cujo óbito ocorreu antes do sétimo dia de doença. Estes resultados comprovam a importância de incluir a FMB no diagnóstico diferencial da dengue, especialmente em regiões onde têm sido relatados casos desta zoonose, cuja letalidade é elevada, na ausência de tratamento específico precoce / Acute febrile disease s are common and often associated with infectious agents in tropical countries such as Brazil. With nonspecific clinical manifestations and hard to differentiate with a number of endemic disea ses such as dengue, leptospirosis , and other fatal diseases, Brazilian S potted F ever (BSF) has rarely been considered in the diagnosis, fact that with the consequent delay in the specific antimicrobial treatment, has determined high lethality often observe d in our country. Dengue is one of the most important and frequent infectious diseases in Brazil, where epidemics are reported periodically in the State of Rio de Janeiro. During dengue fever outbreaks, the possibility of errors in diagnosis d ue to clinica l similarity, BSF should be considered in the differential diagnosis of patients with fever, headache , and rash. In this context, considering the hypothesis that BSF , a neglected zoonosis transmitted by ticks, for lack of clinical suspicion, may not have b een identified during the dengue outbreak occurred in the years 2010 - 2011, a retrospective study was performed based on secondary data and samples placed in public health laboratory. Blood samples from patients with suspected dengue that were serologically discarded during the period of January 2010 to June 2011 in the state of Rio de Janeiro, were subjected to PCR amplification using specific rickettsial primers for gltA and rOmpA genes . From the eligibility criteria preconi z ed, only 3 19 samples of 4,319 c ases identified were submitted to BSF research . Rickettsia rickettsii was identified in two fatal cases in the city of Rio de Janeiro and both patients had nonspecific clinical picture without rash, whose death occurred before the seventh day of illness. T hese results demonstrate the importance of including BSF in the differential diagnosis of dengue, specially in regions where cases of this zoonotic disease have been reported , whose lethality is high in the absence of early specific treatment
128

Epidemiologia das riquetsioses em área de foco silencioso para febre maculosa brasileira, município de Santa Cruz do Escalvado, Minas Gerais.

Pena, Dárlen Cristhiê Hermelinda January 2007 (has links)
Submitted by Maurílio Figueiredo (maurilioafigueiredo@yahoo.com.br) on 2013-03-12T21:44:56Z No. of bitstreams: 1 DISSERTAÇÃO_EpidemiologiaRiquetsiosesÁrea.PDF: 5058201 bytes, checksum: 49dcb477bb4df804ac26bb580665dbc9 (MD5) / Approved for entry into archive by Neide Nativa (neide@sisbin.ufop.br) on 2013-03-15T15:59:28Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO_EpidemiologiaRiquetsiosesÁrea.PDF: 5058201 bytes, checksum: 49dcb477bb4df804ac26bb580665dbc9 (MD5) / Made available in DSpace on 2013-03-15T15:59:28Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO_EpidemiologiaRiquetsiosesÁrea.PDF: 5058201 bytes, checksum: 49dcb477bb4df804ac26bb580665dbc9 (MD5) Previous issue date: 2007 / A Ordem Rickettsiales abriga um grupo de parasitas intracelulares obrigatórios, responsáveis por várias doenças humanas conhecidas como riquetsioses. Artrópodes hematófagos e seus hospedeiros são responsáveis pela disseminação da doença ao homem. Desde a década de 20, o Brasil apresenta histórico de doença riquetsial, onde a febre maculosa Brasileira destaca-se como a mais comum e a mais letal dessas riquetsioses. Embora os métodos sorológicos ainda sejam os mais indicados na confirmação da doença, o emprego de técnicas de biologia molecular vem modelando uma nova realidade ao diagnosticar e detectar cada vez mais patógenos específicos em todo o mundo. O município de Santa Cruz do Escalvado, localizado no Vale do Piranga, Zona da Mata, Minas Gerais, é considerado foco antigo para riquetsioses. Dentro do município, na localidade de Soberbo foi construída em 2004, a Usina Hidrelétrica de Candonga, alterando assim, a paisagem natural da região. Com o objetivo de compreender a atual situação desse município, dentro de uma concepção de ocupação e transformação do espaço geográfico como nosso marco teórico, buscamos avaliar o nível de transmissão de riquetsioses na população de animais domésticos e silvestres coletados em duas localidades pertencentes ao município, utilizando métodos sorológicos e ferramentas da biologia molecular. Foram capturados 94 vertebrados silvestres dentre eles, os roedores Rattus rattus, Nectomys squamipes e Oryzomys subflavus, além de gambás Didelphis aurita. Dos roedores capturados, foram obtidos tecidos (fígado e baço). Foram coletados 427 ectoparasitos, entre Amblyomma cajennense, Rhipicephalus sanguineus, Anocentor nitens, Boophilus microplus e pulgas da espécie Ctenocephalides canis em animais domésticos (cães e eqüinos). Foram também coletadas 166 amostras de soro dos roedores e dos animais domésticos, sendo estas submetidas à reação de imunofluorescência indireta utilizando antígenos específicos para Rickettsia rickettsii, Rickettsia parkeri, Rickettsia felis, Rickettsia bellii e Rickettsia amblyommii. Após a extração de DNA das amostras de tecidos de roedores e de pools dos ectoparasitos coletados, foi realizada a amplificação através de PCR duplex, contendo pares de oligonucleotídeos iniciadores gênero-específicos (CS e 17kDa), sendo o produto obtido reamplificado com um par de iniciadores internos de 17 kDa (full nested PCR). Os produtos amplificados foram visualizados em gel de poliacrilamida 8% corado pela prata e as amostras positivas foram purificadas, seqüenciadas e comparadas com outras seqüências depositadas no GenBank. A análise das seqüências obtidas de tecidos de roedores permitiu a identificação do gênero Rickettsia em pools de ectoparasitos das espécies A. cajennense, A. nitens e B. microplus coletados em eqüinos e da espécie R. sanguineus em pulgas coletadas em cães. Os dados sorológicos apontam o R. rattus como o único roedor sororeativo com 81,25% de positividade para riquétsias do Grupo da febre maculosa, comparado aos demais roedores capturados, cujos resultados sorológicos foram negativos. Foi também encontrada uma freqüência sorológica relativamente expressiva entre os gambás capturados apresentando 14,3% para R. rickettsii e 14,3% para riquétsias do Grupo da febre maculosa (GFM). Os eqüídeos apresentaram 5,4% de sororeatividade para R. bellii e 2,7% para riquétsias do GFM, enquanto os cães apresentaram somente 2% para R. rickettsii e 2% para R. parkeri. ___________________________________________________________________________________ / ABSTRACT: The Order Rickettsiales evolves a group of obligate intracellular parasites, responsible for many diseases known as rickettsioses. Hematophagous arthropods and their hosts are responsible for the disease dissemination to man. Since the 20’s, Brazil shows a description of the rickettsial disease, where the Brazilian spotted fever appears as the most common and with more high case-fatality ratio rickettsiose. Although serologic methods continues to be most indicated in the disease’s confirmation, the use of molecular biology techniques has been molding a new reality in diagnoses and detect even more specific pathogens in the whole wide world. The city of Santa Cruz do Escalvado, located in the Piranga Valley, Zona da Mata, Minas Gerais, is considered an old focus for rickettsioses. In the city, in Soberbo, was built in 2004 the hydroelectric UHE-Candonga, modifying then, the natural landscape of the place. Trying to comprehend the current situation of this place, considering the occupation and transformation of the geographic space, we have investigated the level of rickettsioses infection in domestic and wild animal’s population of two localities of the city, by using serologic and molecular biology methods. There were captured 94 wild vertebrates among them, the rodent Rattus rattus, Nectomys squamipes and Oryzomys subfalus, and also Didelphis marsupialis opossum. Of the rodents captured, was made a tissue collection (liver and spleen). There were collected 427 ectoparasites among Amblyomma cajennense, Rhipicephalus sanguineus, Anocentor nitens, Boophilus microplus and Ctenocephalides canis fleas in domestic animals (canines and equines). There were also collected 166 samples of serum of rodents and of domestic animals, and those samples were evaluated through indirect immunofluorescence reaction using specific antigen for Rickettsia rickettsii, Rickettsia parkeri, Rickettsia felis, Rickettisia bellii, and Rickettisia amblyommii. DNA obtained from rodent tissue samples and from pools of collected ectoparasites, was amplified by a PCR duplex system, with oligonucleotides primers pairs (CS and 17kDa genes), and the obtained product was re-amplified with a pair of inner primers for 17 kDa gene (full nested PCR). The amplified product were visualized in polyacrylamide gel 8% silver stained and the positive samples were purified, sequenced, and compared with others sequences in the GenBank. The analysis of the sequences obtained from rodent tissues allowed the identification of Rickettsia ssp sequence, as well as in pools of ectoparasites from A. cajennense, A. nitens and B. microplus species collected in equines and the R. sanguineus and fleas collected in canines. The serologic data points the R. rattus as the only rodent with 81,25% of seroreactivity to spotted fever-group rickettsiae (SFG) when compared to the rest of captured rodents, with negative serologic results. There were also found a relatively expressive serologic frequency among opossums captured with 14,3% to R. rickettsii and 14,3% to spotted fever-group rickettsiae (SFG). The equines showed 5,4% of seroreactivity to R. bellii and 2,7% to spotted fever-group rickettsiae (SFG), while canines showed only 2% to R. rickettsii and 2% to R. parkeri.
129

Anotação e montagem de transcriptomas de intestino médio e ovários do carrapato Amblyomma sculptum, antes e após a infecção por Rickettsia amblyommii / Annotation and de novo assembly of transcriptomes from midguts and ovaries of Amblyomma sculptum ticks, before and after infection with Rickettsia amblyommii

Moreira, Higo Nasser Sant’anna 29 February 2016 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-01-23T15:42:30Z No. of bitstreams: 1 texto completo.pdf: 1904321 bytes, checksum: 732f95d1a780441aa7e91d87b6821bdc (MD5) / Made available in DSpace on 2017-01-23T15:42:30Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1904321 bytes, checksum: 732f95d1a780441aa7e91d87b6821bdc (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo deste trabalho foi construir um catálogo de genes para o genoma funcional dos órgãos internos do carrapato A. sculptum, bem como, avaliar os padrões de expressão gênica no intestino médio (MDG) e ovários (OVA) frente à condições de não-infecção (MNI e ONI) e infecção por Rickettsia amblyommii (MI e OI). Como primeiro passo, foi realizada a construção de um transcriptome de referência à partir da montagem de 9 transcriptomas (200 milhões de reads) derivados do intestino médio (3), dos ovários (2) e das glândulas salivares (4). O De novo assembly gerou um total de 460,445 contigs, a partir dos quais foram preditas 27.308 CDS expressas em no transcriptome total do A. sculptum. O mapeamento das reads derivadas de cada órgão contra o transcriptoma de referencia permitiu a identificação de 25,569 CDS expressas nos intestinos (MDG), 21,230 CDS expressas em ovários (OVA), enquanto que 10.697 CDS foram derivados dos transcriptomas de glândula salivar (SG). A anotação do transcriptoma de referência (27.308 CDS) permitiu a identificação de 23,228 CDS relacionados a processos housekeeping, enquanto que 2.177 CDS apresentaram sequência de peptídeos (SignalP) e foram anotadas como proteínas secretads.Um total de 261 CDS foram anotadas como elementos transponíveis, 20 CDS foram relacionadas à transcritos virais, enquanto que 1,622 permaneceram sem anotação, sendo anotadas com Unknown. Entre as 29 classes de genes housekeeping, destacam-se aqueles relacionados com Sinal de transdução (3.158 CDS), seguido de 1887 CDS anotadas com os transportadores e 1.523 CDS relacionados maquinaria de transcrição. A avaliação individualizada dos transcriptomas MDG e OVA no tocante a infecção e não infecção por R. amblyommii (infectados vs não infectado) revelou um padrão oposto entre os dois órgãos, com quase todos os processos celulares am MDG superexpressos em resposta à infecção por riquétsia, enquanto a maioria dos processos celular em ovário (OVA) foram down regulados em resposta à infecção por R. amblyommii. Essa down regulação de processes em ovários de carrapatos infectados por rickettsiae corrobora estudos in vitro com outras especíceis de carraátos infectados com Rickettsia spp. o que concorda com outros estudos in vivo com foco ovipostue de carrapatos infectados. com queda das funções fisiológicas da femeas ingurgitada e queda no rendimento da oviposição. Também foi observado up-regulação de proteínas no intestino, em resposta à infecção, sendo essas relacionadas com processes de infecção rickettsial em ́celulas de mamíferos bem como outros invertebrados, tais como actina, complexo Arp 2/3, domínio WASP, proteína tirosina quinase, clatrinas, intergrinas e ontre outras. Estes resultados sugerem que, de forma semelhante à verificada em células de mamíferos e em outras 17 espécies de carrapatos, estas proteínas estar envolvidas durante o processo de infecção do trato intestinal de A. sculptum. No entanto, a down regulação das principais vias metabólicas, maquinaria de replicação e de síntese proteica em ovários em resposta à infecção por Rickettsia (OI contra ONI) indica que esta batéria se constiui uma carga metabólica e fisiológica para os ovários. Alpem de sugerir possível alvos a sere avaliados na interação rickettsia-carrapato, estes resultados também dão suporte à outros estudos e estratégicas para uma melhor compreensão da biologia deste vetor, bem como para o desenvolvimento de estratégias de combate e controle biológico, como vacinas e acaricidas. / The aim of this work was to construct a gene catalogue for the functional genome of internal organs from A. sculptum, as well as, to evaluate the patterns of gene expression from midguts and ovaries against non-infection and Rickettsia amblyommii infection condition. First, we construct a reference transcriptome for A. sculptum internal organs assembling 9 transcriptomes (200 million reads) derived from midguts (3), ovaries (2) and salivary glands (4). The assemble generated 460,445 contigs, of which we identified 27,308 CDS expressed at whole A. sculptum transcriptome. The mapping of the reads derived from each organ against this CDS reference allowed the identification of 25,569 CDS expressed at midguts (MDG), 21,230 CDS expressed at ovaries (OVA) while 10,697 CDS were derived from sialomes (SG). The annotation of the reference transcriptome (27,308 CDS) allowed the identification of 23,228 CDS related to housekeeping processes, 2,177 CDS related presented signal peptide sequence by SignalP analysis, been annotated as Secreted group; 261 CDS were annotated as transposable elements, 20 CDS were reçated to viral transcripts and 1,622 remained without annotation, been classified as unknown sequences. Among the 29 classes related to housekeeping processes, stand out those related to sinal transduction 3,158 CDS, followed by 1,887 related to transporters and 1,523 CDS related to transcription machinery. The individualized evaluation of the MDG and OVA dataset regarding rickettsial infection (infected vs non-infected) reveals an opposite pattern, with almost all midgut processes more abundant in response to rickettsial infection, while most of all ovarian processes were down regulated in response to rickettsial infection, which agrees to other in vivo studies focusing ovipostue of infected ticks. Regarding MDG datasets, we have observed more abundance of host protein related to rickettsial infection processes at mammals and tick cells, such as actin, Arp 2/3 complex, WASP domain, protein tyrosine kinase, clathrins, intergrins and other. These results suggest that, similarly to verified at mammals cells and other tick specie, these proteins could be play a role during the mechanism of infection of A. sculptum midguts by R. amblyommii. However, the down regulation of metabolic pathways, replication and protein synthesis machinery at ovaries in response to rickettsial infection (OI versus ONI) indicates that R. amblyommii play role as a metabolic and physiological burden for ovaries. These results suggest putative candidates proteins for a rickettsial infection mechanism of A. sculptum midguts and give support for further studies and strategies focused on biology control of the tick, as well, a better understanding about the interface A. sculptum – SFG rickettsiae.
130

The Host-pathogen Relationship in Rickettsia: Epidemiological Analysis of RMSF in Ohio and a Comparative Molecular Analysis of Four vir genes

Carmichael, Jennifer Rose 19 March 2008 (has links)
No description available.

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