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Characterisation and recombinant expression of antigens for the rapid diagnosis of West Nile virus infectionJody Hobson-Peters Unknown Date (has links)
West Nile Virus (WNV) is a mosquito-borne pathogen of global significance. It is active on several continents and is responsible for recent outbreaks of fever and fatal encephalitis in humans and horses. While highly virulent strains have been reported in Europe, North, Central and South America, only a benign subtype of WNV (Kunjin virus – KUNV) occurs in Australia. However, virulent, exotic WNV strains are seen as a significant threat to Australia due to the ease with which this virus can move between continents and the presence of suitable vectors and hosts already within Australia. KUNV and WNV subtypes are antigenically and genetically very closely related and cross-react in traditional serological tests. This cross-reactivity makes it very difficult to differentiate between KUNV and WNV infections using standard serological tests. The aim of this thesis was to identify immunogenic epitopes unique to KUNV or WNV and to use these epitopes in the development of a rapid assay that would enable the diagnosis of and surveillance for exotic virulent strains of WNV in Australia. The rapid diagnostic platform chosen was a red blood cell (RBC) agglutination assay that was originally patented and commercialised by AGEN Biomedical Ltd. The RBC agglutination assay reagent consists of the Fab region of a human erythrocyte-specific monoclonal antibody (mAb) conjugated to the epitope of interest (in this instance, a WNV-specific peptide). This bi-functional reagent causes the agglutination of the patient’s erythrocytes in the presence of WNV-specific antibody in the patient’s serum. Traditionally, these RBC agglutination reagents have been produced by chemical conjugation. However, a potentially easier and cheaper method involves the linking of the gene encoding the erythrocyte-specific antibody to that encoding the epitope to create a recombinant version of the bi-functional agglutination reagent through expression using prokaryotic or eukaryotic systems. To identify potential differential epitopes, 18 mAbs to WNV (NY99 strain) prM and envelope (E) proteins were assessed. One mAb (17D7) differentially recognised WNV and KUNV in ELISA and maintained recognition of its corresponding epitope upon reduction and carboxymethylation of the viral antigen, suggesting a continuous (linear) epitope. Using synthetic peptides, the epitope was mapped to a 19 amino acid sequence (WN19: E147-165) encompassing the WNV NY99 E protein glycosylation site at position 154. An amino acid substitution at position E156 of many KUNV strains abolishes this glycosylation moiety. The inability of WNV-positive horse and mouse sera to bind the synthetic peptides indicated that glycosylation was required for recognition of peptide WN19 by WNV-specific antibodies in sera. N-linked glycosylation of WN19 was achieved through expression of the peptide as a C-terminal fusion protein in mammalian cells and specific reactivity of WNV-positive horse sera to the glycosylated WN19 fusion protein was shown by Western blot. Additional sera collected from horses that had been infected with Murray Valley encephalitis virus (MVEV), which is similarly glycosylated at position E154 and exhibits high sequence identity to WNV NY99 in this region, also recognised the recombinant peptide. In contrast, no reactivity with the recombinant peptide was observed by sera from horses infected with the unglycosylated WNV subtype, KUNV. Failure of most WNV- and MVEV-positive horse sera to recognise the epitope as a deglycosylated fusion protein (75% and 100% respectively) confirmed that the N-linked glycan is important for antibody recognition of the peptide. Together, these results suggest that the induction of antibodies to the WN19 epitope during WNV infection of horses is generally associated with E protein glycosylation of the infecting viral strain. To assess the feasibility of using peptide WN19 in a rapid immunoassay, the peptide was recombinantly fused to a RBC (glycophorin)-specific single chain antibody (scFv) using previously published constructs which were developed for the bacterial expression of similar bi-functional reagents. To facilitate glycosylation of peptide WN19, the genes for the bi-functional agglutination reagents were subsequently cloned into eukaryotic expression vectors. An additional set of constructs were also produced in which the genes for the variable regions of the anti-RBC antibody were cloned into a vector for the secreted expression of an intact, humanised IgG1 molecule. Stable cell lines were produced for each of these constructs and secreted up to 700 ng/mL glycophorin-reactive antibody. The secreted recombinant protein could be harvested directly from the cell culture medium and used in RBC agglutination assays, where these bi-functional agglutination reagents could be cross-linked either with mAb 17D7 or by anti-peptide WN19 antibodies present in WNV-positive horse serum. The WNV NY99 prM protein was also identified as a useful marker of WNV-infection in horses, as well as a putative antigen to differentiate equine WNV NY99 and KUNV infections using Western blot. Two anti-WNV prM mAbs were also generated in this study and will be extremely valuable in future studies. Preliminary analysis of the prM epitope(s) bound by these mAbs and WNV-immune sera indicate that the binding site(s) is likely to be localised to pr and is conformational.
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Characterisation and recombinant expression of antigens for the rapid diagnosis of West Nile virus infectionJody Hobson-Peters Unknown Date (has links)
West Nile Virus (WNV) is a mosquito-borne pathogen of global significance. It is active on several continents and is responsible for recent outbreaks of fever and fatal encephalitis in humans and horses. While highly virulent strains have been reported in Europe, North, Central and South America, only a benign subtype of WNV (Kunjin virus – KUNV) occurs in Australia. However, virulent, exotic WNV strains are seen as a significant threat to Australia due to the ease with which this virus can move between continents and the presence of suitable vectors and hosts already within Australia. KUNV and WNV subtypes are antigenically and genetically very closely related and cross-react in traditional serological tests. This cross-reactivity makes it very difficult to differentiate between KUNV and WNV infections using standard serological tests. The aim of this thesis was to identify immunogenic epitopes unique to KUNV or WNV and to use these epitopes in the development of a rapid assay that would enable the diagnosis of and surveillance for exotic virulent strains of WNV in Australia. The rapid diagnostic platform chosen was a red blood cell (RBC) agglutination assay that was originally patented and commercialised by AGEN Biomedical Ltd. The RBC agglutination assay reagent consists of the Fab region of a human erythrocyte-specific monoclonal antibody (mAb) conjugated to the epitope of interest (in this instance, a WNV-specific peptide). This bi-functional reagent causes the agglutination of the patient’s erythrocytes in the presence of WNV-specific antibody in the patient’s serum. Traditionally, these RBC agglutination reagents have been produced by chemical conjugation. However, a potentially easier and cheaper method involves the linking of the gene encoding the erythrocyte-specific antibody to that encoding the epitope to create a recombinant version of the bi-functional agglutination reagent through expression using prokaryotic or eukaryotic systems. To identify potential differential epitopes, 18 mAbs to WNV (NY99 strain) prM and envelope (E) proteins were assessed. One mAb (17D7) differentially recognised WNV and KUNV in ELISA and maintained recognition of its corresponding epitope upon reduction and carboxymethylation of the viral antigen, suggesting a continuous (linear) epitope. Using synthetic peptides, the epitope was mapped to a 19 amino acid sequence (WN19: E147-165) encompassing the WNV NY99 E protein glycosylation site at position 154. An amino acid substitution at position E156 of many KUNV strains abolishes this glycosylation moiety. The inability of WNV-positive horse and mouse sera to bind the synthetic peptides indicated that glycosylation was required for recognition of peptide WN19 by WNV-specific antibodies in sera. N-linked glycosylation of WN19 was achieved through expression of the peptide as a C-terminal fusion protein in mammalian cells and specific reactivity of WNV-positive horse sera to the glycosylated WN19 fusion protein was shown by Western blot. Additional sera collected from horses that had been infected with Murray Valley encephalitis virus (MVEV), which is similarly glycosylated at position E154 and exhibits high sequence identity to WNV NY99 in this region, also recognised the recombinant peptide. In contrast, no reactivity with the recombinant peptide was observed by sera from horses infected with the unglycosylated WNV subtype, KUNV. Failure of most WNV- and MVEV-positive horse sera to recognise the epitope as a deglycosylated fusion protein (75% and 100% respectively) confirmed that the N-linked glycan is important for antibody recognition of the peptide. Together, these results suggest that the induction of antibodies to the WN19 epitope during WNV infection of horses is generally associated with E protein glycosylation of the infecting viral strain. To assess the feasibility of using peptide WN19 in a rapid immunoassay, the peptide was recombinantly fused to a RBC (glycophorin)-specific single chain antibody (scFv) using previously published constructs which were developed for the bacterial expression of similar bi-functional reagents. To facilitate glycosylation of peptide WN19, the genes for the bi-functional agglutination reagents were subsequently cloned into eukaryotic expression vectors. An additional set of constructs were also produced in which the genes for the variable regions of the anti-RBC antibody were cloned into a vector for the secreted expression of an intact, humanised IgG1 molecule. Stable cell lines were produced for each of these constructs and secreted up to 700 ng/mL glycophorin-reactive antibody. The secreted recombinant protein could be harvested directly from the cell culture medium and used in RBC agglutination assays, where these bi-functional agglutination reagents could be cross-linked either with mAb 17D7 or by anti-peptide WN19 antibodies present in WNV-positive horse serum. The WNV NY99 prM protein was also identified as a useful marker of WNV-infection in horses, as well as a putative antigen to differentiate equine WNV NY99 and KUNV infections using Western blot. Two anti-WNV prM mAbs were also generated in this study and will be extremely valuable in future studies. Preliminary analysis of the prM epitope(s) bound by these mAbs and WNV-immune sera indicate that the binding site(s) is likely to be localised to pr and is conformational.
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Characterisation and recombinant expression of antigens for the rapid diagnosis of West Nile virus infectionJody Hobson-Peters Unknown Date (has links)
West Nile Virus (WNV) is a mosquito-borne pathogen of global significance. It is active on several continents and is responsible for recent outbreaks of fever and fatal encephalitis in humans and horses. While highly virulent strains have been reported in Europe, North, Central and South America, only a benign subtype of WNV (Kunjin virus – KUNV) occurs in Australia. However, virulent, exotic WNV strains are seen as a significant threat to Australia due to the ease with which this virus can move between continents and the presence of suitable vectors and hosts already within Australia. KUNV and WNV subtypes are antigenically and genetically very closely related and cross-react in traditional serological tests. This cross-reactivity makes it very difficult to differentiate between KUNV and WNV infections using standard serological tests. The aim of this thesis was to identify immunogenic epitopes unique to KUNV or WNV and to use these epitopes in the development of a rapid assay that would enable the diagnosis of and surveillance for exotic virulent strains of WNV in Australia. The rapid diagnostic platform chosen was a red blood cell (RBC) agglutination assay that was originally patented and commercialised by AGEN Biomedical Ltd. The RBC agglutination assay reagent consists of the Fab region of a human erythrocyte-specific monoclonal antibody (mAb) conjugated to the epitope of interest (in this instance, a WNV-specific peptide). This bi-functional reagent causes the agglutination of the patient’s erythrocytes in the presence of WNV-specific antibody in the patient’s serum. Traditionally, these RBC agglutination reagents have been produced by chemical conjugation. However, a potentially easier and cheaper method involves the linking of the gene encoding the erythrocyte-specific antibody to that encoding the epitope to create a recombinant version of the bi-functional agglutination reagent through expression using prokaryotic or eukaryotic systems. To identify potential differential epitopes, 18 mAbs to WNV (NY99 strain) prM and envelope (E) proteins were assessed. One mAb (17D7) differentially recognised WNV and KUNV in ELISA and maintained recognition of its corresponding epitope upon reduction and carboxymethylation of the viral antigen, suggesting a continuous (linear) epitope. Using synthetic peptides, the epitope was mapped to a 19 amino acid sequence (WN19: E147-165) encompassing the WNV NY99 E protein glycosylation site at position 154. An amino acid substitution at position E156 of many KUNV strains abolishes this glycosylation moiety. The inability of WNV-positive horse and mouse sera to bind the synthetic peptides indicated that glycosylation was required for recognition of peptide WN19 by WNV-specific antibodies in sera. N-linked glycosylation of WN19 was achieved through expression of the peptide as a C-terminal fusion protein in mammalian cells and specific reactivity of WNV-positive horse sera to the glycosylated WN19 fusion protein was shown by Western blot. Additional sera collected from horses that had been infected with Murray Valley encephalitis virus (MVEV), which is similarly glycosylated at position E154 and exhibits high sequence identity to WNV NY99 in this region, also recognised the recombinant peptide. In contrast, no reactivity with the recombinant peptide was observed by sera from horses infected with the unglycosylated WNV subtype, KUNV. Failure of most WNV- and MVEV-positive horse sera to recognise the epitope as a deglycosylated fusion protein (75% and 100% respectively) confirmed that the N-linked glycan is important for antibody recognition of the peptide. Together, these results suggest that the induction of antibodies to the WN19 epitope during WNV infection of horses is generally associated with E protein glycosylation of the infecting viral strain. To assess the feasibility of using peptide WN19 in a rapid immunoassay, the peptide was recombinantly fused to a RBC (glycophorin)-specific single chain antibody (scFv) using previously published constructs which were developed for the bacterial expression of similar bi-functional reagents. To facilitate glycosylation of peptide WN19, the genes for the bi-functional agglutination reagents were subsequently cloned into eukaryotic expression vectors. An additional set of constructs were also produced in which the genes for the variable regions of the anti-RBC antibody were cloned into a vector for the secreted expression of an intact, humanised IgG1 molecule. Stable cell lines were produced for each of these constructs and secreted up to 700 ng/mL glycophorin-reactive antibody. The secreted recombinant protein could be harvested directly from the cell culture medium and used in RBC agglutination assays, where these bi-functional agglutination reagents could be cross-linked either with mAb 17D7 or by anti-peptide WN19 antibodies present in WNV-positive horse serum. The WNV NY99 prM protein was also identified as a useful marker of WNV-infection in horses, as well as a putative antigen to differentiate equine WNV NY99 and KUNV infections using Western blot. Two anti-WNV prM mAbs were also generated in this study and will be extremely valuable in future studies. Preliminary analysis of the prM epitope(s) bound by these mAbs and WNV-immune sera indicate that the binding site(s) is likely to be localised to pr and is conformational.
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Desenvolvimento de teste rápido para detecção de rotavírus: imunoensaio de captura e aglutinação em látexSilveira, Waldemir de Castro January 2005 (has links)
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Previous issue date: 2005 / Fundação Oswaldo Cruz. Instituto de Tecnologia em Imunobiológicos. Rio de Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil. / O rotavírus humano (RV) pode ser detectado prontamente pelo método de aglutinação do látex (LTE), com elevada sensibilidade e especificidade, através da reação cruzada com o anticorpo anti-rotavírus decarneiro. As partículas de látex revestidas com a imunoglobulina G anti-rotavírus, são especificamente aglutinadas na presença do RV, com resultados macroscopicamente evidentes dentro de poucos minutos. Para a sensibilidade e a especificidade do método
de LTE proposto, comparou-se com outro método similar (Rota-Kit Slidex®; BioMérieuxl), um total de 81 amostras fecais de crianças até 5 anos com gastroenterite aguda. Com 36 amostras diarréicas RV-positivos e 45 RV-negativos, a ensibilidade analítica do teste de LTE proposto foi > 99,99%, e a especificidade analítica também foi > 99,99%. O LTE demonstrou ser capaz de detectar partículas de rotavírus em fezes diarréicas em concentrações 20 vezes menores que o limite de detecção do Rota-Kit Slidex®. A freqüência de testes positivos de LTE pareceu ser proporcionalà concentração de
viríons na amostra fecal. O LTE demonstrou uma sensibilidade de 94,0% (34
de 36 positivos), e uma especificidade > 99,99% (45de 45 negativas) quando
comparado com o Rotazyme II®, um ensaio imunoenzimático (Abbott
Laboratories). O método do LTE é rápido, facilmenteutilizável para detectar
o RV em amostra fecal de crianças e é apropriado para a aplicação como um
teste diagnóstico simples, principalmente para triagem de grandes grupos de
pacientes. O LTE é estável por pelo menos 2 anos searmazenado sob
refrigeração (4°C) e se mostra útil para laboratórios de pequeno porte, para
rotinas ambulatoriais, de emergências e de triagem e finalmente, para
discriminar amostras negativas que poderão então ser testadas por testes mais
sensíveis. / Human rotavírus (HRV) can readily be detected by the latex agglutination
assay method (LTE), with raised sensitivity and specificity, based on crossed
reaction with the anti-rotavirus sheep antibody. The latex particles coated
with anti-rotavirus immunoglobulin G, agglutinates specifically when in
contact with HRV in few minutes, with evident macroscopically results. The
sensitivity and the specificity performance of the proposed method (LTE),
was compared with another similar method (Rota-Kit Slidex®, BioMérieux), a
total of 81 specimens from children with acute gastroenteritis were tested.
With 36 HRV positive samples and 45 HRV negative samples, the analytical
sensitivity of LTE was better than 99,99% and the analytical specificity, also,
was better than 99,99%. The LTE demonstrated to be capable to detect particles of HRV in fecal samples in concentrations20 lesser times that the limit of detection of Rota-Kit Slidex®. The frequency of positive tests of LTE seemed to be proportional to the concentration of virions in the fecal
sample. The LTE demonstrated a sensitivity of 94,0%(34 of 36 positives), and a specificity >99,99% (45 of 45 negatives) whencompared with Rotazyme II® (Abbott Laboratories). The method of the LTE is fast and easily usable to detect HRV in children fecal sample and is appropriate for
application as a test of simple diagnosis, mainly for screening of great groups
of patients. The LTE is stable per at least 2 yearsif stored under refrigeration
(4°C) and it shows useful for small laboratories, clinic routines, emergence
rooms and screenings and finally to discriminate negative samples that could
then be tested by more sensible tests.
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Resposta sorológica de bovinos vacinados contra o Clostridium chauvoei avaliada pelos testes de aglutinação em placa e ElisaAraujo, Rafael Ferreira [UNESP] 19 February 2009 (has links) (PDF)
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araujo_rf_me_jabo.pdf: 248554 bytes, checksum: e7d4bd27c73efa391fb0fac3082dd622 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O carbúnculo sintomático é um problema sanitário mundial, responsável por elevados coeficientes de mortalidade em bovinos e ovinos. A imunização dos animais jovens, seguida de reforço anual até 2,5 anos de idade, é a principal medida profilática. Foram realizados três experimentos distintos com intuito de avaliar as respostas sorológicas de bovinos vacinados contra o carbúnculo sintomático, pelos testes de aglutinação em placa e Elisa, empregando-se como antígenos a cepa de referência (MT) e uma cepa de campo (SP). No primeiro experimento, os bezerros foram organizados em três grupos (G1, G2 e G3) e submetidos a três protocolos distintos de vacinação empregando-se uma vacina comercial polivalente contra clostridioses. O G1 foi primovacinado aos 4 meses de idade e recebeu o reforço na desmama (8 meses). O G2 recebeu a primeira dose na desmama e reforço 30 dias após. O G3 foi vacinado somente na desmama. As coletas de soro foram realizas aos 4, 8, 9 e 10 meses de idade dos bezerros. O G1 apresentou a melhor resposta sorológica em comparação aos outros dois protocolos. Quando a avaliação dos grupos foi realizada aos 10 meses de idade, independente do protocolo empregado, a resposta sorológica foi similar. No segundo experimento, foi avaliada a imunidade natural passiva de bezerros, filhos de vacas vacinadas até 30 dias antes do parto (2ª dose), empregando-se duas vacinas comercias polivalente contra clostridioses. As coletas de soro foram realizadas aos (±)7, 45 e 90 dias de idade dos bezerros. Independente das vacinas empregadas na imunização ativa das mães, a resposta sorológica passiva dos bezerros avaliados foi similar até os 3 meses de idade. Houve uma correlação linear da resposta sorológica passiva dos bezerros com a data de vacinação das mães e o dia do parto quando empregado o teste de Elisa. No terceiro experimento, as 30 vacas... / Black leg disease is one of the most important sanitary problem, responsible for high levels of mortality observed in bovines and ovines herds. The vaccination of young animals, followed by annual booter until 2,5 years-old, is the major preventive measure against outbreaks. Three distinct experiments were conducted to measure the vaccinal response from bovines. The vaccinal strains used were the reference MT and field Clostridium chauvoei isolated. Sera from vaccinated animals were tested by agglutination and Enzyme Linked Immunosorbent Assay (Elisa), both standardized for the present study. First experiment, calves were divided into three groups (G1, G2 and G3); and submitted to three vaccination schedule with a polyvalent vaccine. The G1 received first vaccine at 4 months of age and a subsequent booster after calving (8 month-old). The G2 received first vaccine dose after calving and booster at 30 days after. The G3 received only one vaccine dose at 8 months. The sera were colleted at 4, 8, 9 and 10 months for all groups studied. The G1 group showed the best serological response at 10 months of age in comparison to G2 e G3 and control. Moreover, at 10 months of age all groups presented similar levels of serological response. The second experiment, the natural immunity of calves, separated from their mothers vaccinated 30 days before calving with two polyvalent vaccines. The respective serum was colleted at (±) 7, 45 and 90 days of age. All calves presented similar serological response at 3 months of age, independent of vaccinal strain used. The third experiment, 30 heifers, Nelore race, aged above 4 years-old, without vaccination against black leg, were vaccinated with two Clostridium strains. When the SP strain was used the serological response was considered good in G3 (first experiment), second and third experiment for agglutination assay. To compare both techniques, agglutination... (Complete abstract click electronic access below)
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A (DES) aglutinação sintático-semântico-discursiva: um enfoque enunciativo do verbo intransitivo em reportagens impressasNóbrega, Fabíola 30 April 2015 (has links)
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Previous issue date: 2015-04-30 / The syntactic-semantic-discursive agglutination is a process concerning to the junction of the complement in the verb designed by Traditional Grammar (GT) as intransitive, having no material occupation as the object. However, in some situations, these verbs can be used like complement materialized in the syntax plan, with the syntactic-semantic-discursive detachment. This phenomenon is caused by enunciative reasons. Therefore, we had as main objective to analyze the syntactic-semantic-discursive agglutination and detachment of the verbs defined by the Traditional Grammar in an enunciation perspective, using, for this, printed reports. In order to answer this need, we developed the following specific objectives: to characterize the syntactic-semantic-discursive agglutination/ detachment as an enunciative phenomenon; analyze the meaning of a linguistic element (the verb) through two biases: theme (contextual meaning) and linguistic significance (in dictionaries sense) by combining with the active comprehension; understand how the syntactic-semantic-discursive agglutination and detachment are used in targeted verbs in a printed report, observing the thematic content, compositional elements and the style; discuss the factors that provide the syntactic-semantic-discursive agglutination the syntactic-semantic-discursive detachment in selected verbs for analysis. For this purpose, we used the theoretical construct defended by Bakhtin / Voloshinov (1981, 1926), Bakhtin (2003), as well as researchers of the linguistic thought from the Bakhtin Circle. Our corpus comprised twenty-two printed reports of Veja magazine, published in the period from 1968 to 2013 and selected in <http://veja.abril.com.br/acervodigital>. At first, we discuss the thematic content, compositional elements and the style of chosen reports. Subsequently, we analyze the syntactic-semantic-discursive agglutination in the verbs die, live, sunrise, fall, mature, aging, fight, react, dream, cry, smile, sleep, grow and laugh. And subsequently, we described some of the syntactic-semantic-discursive detachment in some of these verbs. Thus, we can say that, in this work, a syntactic phenomenon (the intransitive verbs) was observed by the Theory of Enunciation, according to Bakhtin / Voloshinov (1981). / A aglutinação sintático-semântico-discursiva é um processo que diz respeito à junção do complemento no verbo concebido pela Gramática Tradicional (GT) como intransitivo, não tendo a ocupação material do lugar de objeto. No entanto, em algumas situações, estes verbos podem ser usados com o complemento materializado no plano da sintaxe, havendo a desaglutinação sintático-semântico-discursiva. Este fenômeno é provocado por motivações de ordem enunciativa. Para tanto, tivemos como objetivo geral analisar a (des)aglutinação sintático-semântico-discursiva em uma perspectiva enunciativa nos verbos definidos pela GT como intransitivos, utilizando, para isso, reportagens impressas. No propósito de atender a esta necessidade, desenvolvemos os seguintes objetivos específicos: caracterizar a aglutinação e a desaglutinação sintático-semântico-discursiva como um fenômeno enunciativo; analisar o sentido de um elemento linguístico (verbo) através de dois vieses: tema (sentido contextual) e significação linguística (sentido dicionarizado), associando à compreensão ativa; compreender como a aglutinação e a desaglutinação sintático-semântico-discursiva são usadas nos verbos escolhidos em uma reportagem impressa, observando o conteúdo temático, os elementos composicionais e o estilo; discutir os fatores que proporcionam a (des)aglutinação sintático-semântico-discursiva nos verbos selecionados para a análise. Para tal propósito, recorremos ao construto teórico defendido por Bakhtin/Volochinov (1981, 1926), Bakhtin (2003), além de pesquisadores do pensamento linguístico do Círculo de Bakhtin. Nosso corpus foi composto por vinte e duas reportagens impressas da Revista Veja, publicadas no período de 1968 a 2013 e pesquisadas no site <http://veja.abril.com.br/acervodigital>. A princípio, discutimos o conteúdo temático, os elementos composicionais e o estilo das reportagens escollhidas. Posteriormente, analisamos a aglutinação sintático-semântico-discursiva nos verbos morrer, viver, nascer, cair, amadurecer, envelhecer, lutar, reagir, sonhar, chorar, sorrir, dormir, gritar, crescer e rir. E, posteriormente, discorremos sobre a desaglutinação sintático-semântico-discursiva em alguns destes verbos. Com isso, podemos dizer que, em nossa tese, um fenômeno sintático (os verbos intransitivos) foi observado à luz da Teoria da Enunciação, conforme pontuaram Bakhtin/Volochinov (1981).
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BioprospecÃÃo e atividade biolÃgica de produtos naturais das algas marinhas vermelhas Pterocladiella capillacea e Osmundaria obtusiloba / Bioprospection of natural products from the red marine algae Pterocladiella capillacea and Osmundaria obtusiloba and their biological activitiesDaniel Barroso de Alencar 15 January 2016 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / O ambiente marinho possui grande biodiversidade de algas marinhas, sendo uma rica fonte natural de muitos compostos biologicamente ativos, como, compostos orgÃnicos volÃteis, carotenoides, clorofilas, ficobilinas, terpenos, esteroides, compostos fenÃlicos, alcaloides, polissacarÃdeos, vitaminas e Ãcidos graxos saturados e poli-insaturados, tornando-as cada vez mais procuradas para fins comerciais. O objetivo deste trabalho foi realizar bioprospecÃÃo e avaliar atividades biolÃgicas de produtos naturais das algas marinhas vermelhas Pterocladiella capillcea e Osmundaria obtusiloba. Os extratos etanÃlicos a 70% (EtOH 70%) das algas apresentaram os maiores valores do conteÃdo fenÃlico total (CFT) comparados aos extratos hexÃnicos (Hex). Os resultados do DPPH dos extratos Hex e EtOH 70% da O. obtusiloba foram maiores (43,46% e 99,47%) do que aqueles da P. capillacea (33,04% e 40,81%), na concentraÃÃo de 1.000 μg/mL. Quanto à habilidade de quelaÃÃo de Ãons ferrosos (FIC), observou-se um comportamento inverso, os extratos da P. capillacea apresentaram atividade superior aos da O. obtusiloba. Todos os extratos apresentaram um baixo poder de reduÃÃo de Ãons fÃrricos (FRAP), com variaÃÃo da densidade Ãptica entre 0,054 e 0,180. As atividades antioxidantes de todos os extratos algÃceos, avaliadas pela degradaÃÃo do β-caroteno (BCB), foram superiores a 40%. NÃo foi observada atividade antibacteriana contra as estirpes bacterianas testadas. Entretanto, os extratos das duas espÃcies foram capazes de aglutinar cÃlulas bacterianas Gram positivas de Staphylococcus aureus e Gram negativas de Escherichia coli, Salmonella sorovar Infantis multirresistente e Vibrio harveyi. Os compostos orgÃnicos volÃteis (COVs) e os Ãcidos graxos das algas marinhas vermelhas P. capillacea e O. obtusiloba foram analisados qualitativamente por cromatografia gasosa acoplada à espectrometria de massas (CG-EM) e quantitativamente por cromatografia gasosa (CG) equipada com detector de ionizaÃÃo de chama (DIC). Quanto aos COVs, ao todo foram identificados 31 constituintes diferentes nas espÃcies de algas, sendo alguns deles comuns Ãs duas. Em P. capillacea, dos 21 constituintes identificados, os majoritÃrios foram hexanal (50,4%), 2-pentilfurano (9,2%) e heneicosano (8,8%). Em O. obtusiloba dos dos 21 constituintes identificados, os majoritÃrios foram heneicosano (57,3%), hexanal (20,5%) e 1-pentadeceno (2,6%). Nove Ãcidos graxos foram identificados por CG-EM nas duas espÃcies. Em P. capillacea, os Ãcidos graxos majoritÃrios foram Ãcido palmÃtico (88,8%), Ãcido oleico (3,1%), Ãcido araquidÃnico (2,0%) e Ãcido eicosapentaenoico (1,9%). Em O. obtusiloba, os Ãcidos palmÃtico (55,6%), eicosapentaenoico (9,1%), oleico (8,9%) e araquidÃnico (8,5%) foram os majoritÃrios. A capacidade de sequestro do radical DPPH dos Ãcidos graxos apresentou uma atividade moderada variando de 25,90% a 29,97%. Os Ãcidos graxos de P. capillacea (31,18%) apresentaram uma moderada atividade FIC e os de O. obtusiloba (17,17%), fraca. O FRAP dos Ãcidos graxos de P. capillacea e O. obtusiloba apresentou baixa atividade. Com relaÃÃo ao BCB, a alga P. capillacea apresentou uma atividade de 61,24% na concentraÃÃo de 12,5 μg/mL e O. obtusiloba apresentou uma atividade de 49,13% na concentraÃÃo de 50 μg/mL. Este à o primeiro relato sobre identificaÃÃo e quantificaÃÃo de COVs, de compostos lipofÃlicos em extratos brutos das rodÃfitas P. capillacea e O. obtusiloba na costa Nordeste do Brasil. / There is a great diversity of seaweeds in marine environment that are natural rich sources of a variety of biologically active compounds, such as, volatile organic compounds, carotenoids, chlorophyls, phycobillins, terpenes, steroids, phenolic compounds, alkaloids, polysaccharides, vitamins, saturated and unsaturated fatty acids, one reason for becoming desirable for commercial uses. The objective of this work was to carry on a bioprospection and the evaluation of the biological activity of the natural products from the red marine algae Pterocladiella capillacea and Osmundaria obtusiloba. The 70% ethanolic extracts (70% EtOH) from both species showed higher values of total phenolic compounds (TPC) than hexanic (Hex) ones. The results of DPPH of both extracts, Hex and 70% EtOH, from O. obtusiloba were higher (43.46% and 99.47%) than those from P. capillacea (33.04% and 40.81%), at 1,000 μg/mL concentration. In contrast, the ferrous ion chelation (FIC) activity from P. capillacea extracts was superior to those of O. obtusiloba. All extracts showed low ferric ion reduction (FRAP) activity, with optical density varying from 0.054 to 0.180. The antioxidant activities of all agal extracts, measured by β-carotene bleaching (BCB), were above 40%. No antibacterial activity was observed against the tested strains. However, the extracts of both algae were capable of agglutinating bacterial cells: Gram positive Staphylococcus aureus and Gram negative Escherichia coli, multi-resistant Salmonella sorovar Infantis and Vibrio harveyi. The volatile organic compounds (VOCs) and the fatty acids of the red marine algae P. capillacea and O. obtusiloba were analyzed qualitatively by gas chromatography-mass spectrometry (GC-MS) and quantitatively by gas chromatography with a flame ionization detector (GC-FID). Thirty-one different VOCs were identified in these alga species, some of which are common to both. In P. capillacea, out of twenty-one identified compounds, the major were hexanal (50.4%), 2-pentylfuran (9.2%), and heneicosane (8.8%). On the other hand, in O. obtusiloba, out of twenty-one identified compounds, the major were heneicosane (57.3%), hexanal (20.5%) and 1-pentadecane (2.6%). Nine fatty acids were identified by GC-MS in the two species. In P. capillacea, the principal fatty acids were palmitic acid (88.8%), oleic acid (3.1%), arachidodic acid (2.0%), and eicosapentaenoic acid (1.9%). In O. obtusiloba, palmitic acid (55.6%), eicosapentaenoic (9.1%), oleic (8.9%), and arachidonic (8.5%) were the most important fatty acids found. The scavenging of DPPH free radical of the fatty acids from both species showed a moderate activity, which varied from 25.90% to 29.97%. Fatty acids obtained from P. capillacea (31.18%) exhibited moderate FIC activity, whereas those from O. obtusiloba (17.17%), just weak. The FRAP measured from the fatty acids from both P. capillacea and O. obtusiloba showed low activity. Considering the BCB, the activity of P. capillacea was 61.24% in the 12.5 μg/mL concentration, and for O. obtusiloba, BCB activity was 49.13% in the 50 μg/mL concentration. This is the first report on the identification and quantification of VOC, from crude extracts of the red marine algae P. capillacea and O. obtusiloba, collected in the Northeast coast of Brazil.
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Efeitos biológicos de lectinas de Cratylia mollis em células de adenocarcinoma de próstata humano e em plaquetasFIGUEIRÔA, Evellyne de Oliveira 18 September 2015 (has links)
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Previous issue date: 2015-09-18 / CAPES / Lectinas são proteínas ou glicoproteínas de origem não-imunológica que possuem a capacidade de aglutinar eritrócitos ou outras células e precipitar polissacarídeos ou outras glicoproteínas. Cramoll 1, Cramoll 2, Cramoll 3 e Cramoll 4 são lectinas extraídas das sementes de Cratylia mollis. Cramoll 1,4 é uma mistura de Cramoll 1 e sua isoforma Cramoll 4 e rCramoll foi sintetizada pela técnica de expressão heteróloga, a partir da sequência de aminoácidos de Cramoll 1. Este trabalho objetivou avaliar a atividade indutora de morte celular das lectinas Cramoll 1,4 e rCramoll em células de adenocarcinoma de próstata humano (PC-3), além de verificar as propriedades das lectinas Cramoll 1, Cramoll 2, Cramoll 3 e Cramoll 4 em aglutinar plaquetas lavadas de diferentes tipos sanguíneos humanos e de sangue de coelho. Cramoll 1,4 e rCramoll diminuíram a viabilidade das células PC-3 com o aumento das concentrações das lectinas ou do tempo de exposição. Os valores de concentrações capazes de matar 50% das células PC-3 expostas às lectinas foram 39.69 μg/mL e 29.91 μg/mL para Cramoll 1,4 e rCramoll, respectivamente. Elas apresentaram maior citotoxicidade para células PC-3 quando comparadas à lectina ConA. Tratamento com Cramoll 1,4 e com rCramoll induziu a morte celular por necrose, com um aumento de cerca de 3 vezes nos níveis de superóxido mitocondrial, bem como aumento dos níveis de cálcio citosólico. Quando utilizados inibidores da abertura do poro de transição de permeabilidade mitocondrial não foi observada proteção das células PC-3 no processo de morte celular. Provavelmente, a morte de células PC-3 ocorreu devido aos aumentos nas concentrações de cálcio citosólico e de espécies reativas de oxigênio (EROs) mitocondrial, culminando com uma diminuição na fosforilação oxidativa, deficiência de ATP e privação de energia. Com relação à propriedade em aglutinar plaquetas, a aglutinação ocorreu em maior percentual nas plaquetas provenientes de sangue tipo A e em menor intensidade em plaquetas provenientes de sangue tipo AB e apesar da especificidade a carboidratos diferente entre Cramoll 3 e Cramoll 4, estas isoformas apresentaram semelhança quanto à promoção de aglutinação de plaquetas humanas. Quanto aos ensaios de inibição da aglutinação de plaquetas, foi observado que, na maior parte das vezes, os carboidratos específicos não inibiram completamente a aglutinação de plaquetas. / Lectins are proteins or glycoproteins of non-immune origin that have the ability to agglutinate erythrocytes or other cells and precipitating polysaccharides and glycoproteins other. Cramoll 1, Cramoll 2, Cramoll 3 and Cramoll 4 are lectin extracted from seeds Cratylia mollis. Cramoll 1,4 is a mixture of Cramoll 1 and isoform Cramoll 4. rCramoll was synthesized by heterologous expression technique, from the Cramoll amino acid sequence 1. This study evaluated the activity of inducing cell death of lectins Cramoll 1,4 and rCramoll in human prostate adenocarcinoma cells (PC-3), and evaluate the properties of lectins Cramoll 1, Cramoll 2, Cramoll 3 and Cramoll 4 washed platelets agglutinate in different human blood types and rabbit blood. Cramoll 1,4 and rCramoll decreased viability of PC-3 cells with increasing concentrations of lectins or exposure time. The values of effective concentrations to kill 50% of PC-3 cells treated were 39.69 μg/ml and 29.91 μg/mL for the lectins Cramoll 1,4 and rCramoll, respectively. They showed greater toxicity for PC-3 cells compared to the lectin ConA. Treatment with Cramoll 1,4 and rCramoll induced cell death by necrosis, with an increase about 3 times higher the levels mitochondrial superoxide as well as in cytosolic calcium levels. When used inhibitors opening of the mitochondrial permeability transition pore protection was not observed in PC-3 cells in cell death process. Probably, PC-3 cell death occurred due to these previous increases in cytosolic calcium concentrations and reactive oxygen species (ROS) mitochondrial, culminating in a decrease in oxidative phosphorylation, ATP deficiency and deprivation of energy. Platelet agglutination occurred in a higher percentage in platelets from blood type A and to a lesser intensity in platelets from blood type AB. Despite the specificity of different carbohydrates between Cramoll 3 and Cramoll 4, these isoforms were similar as to promoting platelet agglutination human. As for inhibition assays of platelet agglutination it was observed that, in most of times, the specific carbohydrate didn’t completely inhibit platelet agglutination
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Detecção do vírus dengue pela técnica de aglutinação do látex modelo experimental.Luppino, Plinio Luis 04 June 2007 (has links)
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Previous issue date: 2007-06-04 / Dengue is the arthropod-borne transmitted viral disease of highest worldwide prevalence in mortality and morbidity. The proportion is pandemic ranging 1.6 million of infected patients yearly. Clinical presentation associated to epidemiological factors such as dengue prevalence in the patient s origin have been the only mean for early diagnosis. Laboratorial diagnosis, the conclusive, requires several days when there is viral isolation. Serological methods depend on high level of specific antibodies, and molecular methods are not available for the majority of laboratories of diagnosis and routine. The purpose of this study was to develop an agglutination method using latex to detect dengue virus, using biological samples of mice infected with dengue 1 Mochizuki strain by intracerebral via, and anti-dengue 1 specific antibodies from immunized mice. According to the results, this method was feasible for the dengue viruses diagnosis in positive samples of experimental animals. It provides further approaches for rapid detection of dengue in susceptible populations during the first days of the disease. / A dengue é a doença viral, transmitida por artrópode, de maior prevalência mundial em morbidade e mortalidade. Alcança proporções pandêmicas, estimando-se em 1,6 milhões de doentes anualmente. Manifestações clínicas características, associadas a fatores epidemiológicos, como prevalência da dengue na região de origem do paciente, têm sido os únicos instrumentos de diagnóstico precoce. O diagnóstico laboratorial, que é definitivo, demanda vários dias, quando realizado o isolamento viral. Métodos sorológicos dependem de níveis elevados de anticorpos específicos e os métodos moleculares não estão disponíveis para a maioria dos laboratórios de diagnóstico e rotina. Este estudo teve como objetivo desenvolver método de aglutinação do látex para a detecção do vírus dengue, utilizando amostras biológicas de camundongos infectados por via intracerebral com dengue 1, cepa Mochizuki e anticorpos específicos anti-dengue 1, obtidos de camundongos imunizados. Os resultados obtidos demonstraram a viabilidade deste método para diagnóstico do vírus Dengue em amostras positivas de animais de experimentação, abrindo novas perspectivas para o diagnóstico precoce da dengue na população susceptível, durante os primeiros dias de sintomas.
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Desenvolvimento de um teste rápido de aglutinação em látex para o diagnóstico de Escherichia coli enteropatogênica e Escherichia coli produtora da toxina de Shiga / Development of a rapid latex agglutination test for the diagnosis of enteropathogenic Escherichia coli and Shiga toxin-producing Escherichia coliSantos, Anna Raquel Ribeiro dos 09 May 2014 (has links)
Globalmente ocorrem cerca de 800.000 mortes de crianças menores de cinco anos associadas à diarreia, principalmente na África subsaariana, sul da Ásia e América Latina. Dentre os patógenos causadores de diarreia, Escherichia coli diarreiogênica (DEC) é o agente etiológico bacteriano mais comum, incluindo E. coli enteropatogênica (EPEC) e E. coli produtora da toxina de Shiga e seu subgrupo enterohemorrágica (STEC/EHEC). Os dados epidemiológicos indicam a importância do diagnóstico precoce e sua realização em locais com pouca infraestrutura. Desta forma o objetivo deste trabalho foi o desenvolvimento de um teste rápido, sensível e específico para o diagnóstico de EPEC e STEC/EHEC. Primeiramente, foram definidas diferentes condições do cultivo bacteriano: Dulbecco\'s modified Eagle\'s (DMEM), DMEM contendo 1% de triptona e DMEM pré-condicionado para o cultivo dos isolados de EPEC/EHEC e avaliação da produção/secreção das proteínas secretadas EspA e EspB, utilizando anticorpos monoclonais (MAb) e policlonais (PAb) anti-EspA ou anti-EspB por ELISA indireto. Para a avaliação da liberação das toxinas de Shiga para o sobrenadante do cultivo bacteriano de STEC/EHEC, foram testados diferentes condições de tratamento, o cultivo bacteriano foi tratado com Triton X-100 e o sedimento foi tratado com tampão de lise B-PER utilizando MAb e PAb anti-Stx1 ou anti-Stx2 por ELISA de captura. Subsequentemente, foi desenvolvido e avaliado o teste de aglutinação em látex para a detecção de EspB em isolados de EPEC/EHEC, e Stx1 e Stx2 em isolados de STEC/EHEC. EspB foi definida como biomarcador, o MAb anti-EspB como ferramenta para o diagnóstico de EPEC/EHEC, e a condição ideal para a produção/secreção de EspB foi o cultivo em DMEM. Para o diagnóstico de STEC/EHEC a condição ideal para liberação das toxinas Stx foi o tratamento do cultivo com Triton X-100. Tanto o ELISA, como a aglutinação em látex apresentaram sensibilidades e especificidades exigidas para testes diagnósticos de doenças negligenciadas em países em desenvolvimento e os testes de aglutinação em látex para a detecção destes patógenos foram precisos, rápidos e fáceis de executar, sendo portanto promissores para a utilização em laboratórios com mínima infraestrutura. / There are 800,000 deaths associated with diarrhea worldwide in children under five, and these are mainly in sub-Saharan Africa, Southeast Asia and Latin America. Among the causative pathogens of diarrhea, diarrheagenic Escherichia coli (DEC) is the most common bacterial etiological agent, including enteropathogenic E. coli (EPEC) and Shiga toxin-producing E. coli and its subgroup enterohemorrhagic E. coli (STEC/EHEC). Epidemiological data indicate the importance of early diagnosis and its realization in places with limited resources. Therefore, the objective of this work was to develop a rapid, sensitive and specific test for the diagnosis of EPEC and STEC/EHEC. First, different bacterial growth conditions were evaluated: Dulbecco\'s modified Eagle\'s medium (DMEM) or DMEM containing 1% tryptone, and DMEM pre-conditioned with EPEC/EHEC isolates. The production/secretion of the secreted proteins EspA and EspB was determined by indirect ELISA utilizing anti-EspA or anti-EspB monoclonal (MAb) and polyclonal (PAb) antibodies. Different treatments were tested for their effect on the release of Shiga toxins into the medium of STEC/EHEC bacterial cultures. The bacterial culture supernatant was treated with Triton X-100, and the sediment was treated with B-PER lysis buffer. The toxins release was determined by capture ELISA using anti-Stx1 or anti-Stx2 MAb and PAb. Subsequently, a latex agglutination test was developed and evaluated for the detection of EspB in EPEC/EHEC isolates and of Stx1 and Stx2 in STEC/EHEC isolates. EspB was defined as the biomarker and anti-EspB MAb as the tool for the diagnosis of EPEC/EHEC. The ideal conditions for the production/secretion of EspB were cultivation in DMEM. For the diagnosis of STEC/EHEC, the ideal conditions for the release of Stx were Triton X-100 treatment. ELISA as well as latex agglutination showed the sensitivities and specificities required for diagnostic tests of neglected diseases in developing countries. The latex agglutination test for the detection of these pathogens was precise, rapid and easy to perform, thereby being promising for their utilization in laboratories with limited resources.
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