• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 19
  • 6
  • 5
  • 4
  • 2
  • 1
  • Tagged with
  • 33
  • 33
  • 33
  • 9
  • 8
  • 8
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 5
  • 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.
1

Integrated study of group B streptococcus and human ureaplasmas � the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potential perinatal pathogens. Their relationships between genotypes and pathogenesis of GBS and ureaplasma infection were still not well understood, one of the reason is that both of them are still short of a very practical genotyping system. In the study, to solve the above problem we developed genotyping systems for the organisms (the second section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasma species (U. parvum and U. urealyticum). Further, based on the heterogeneity of ureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotyping systems showed that the genotyping systems were practical alternative assays for the conventional serotyping and they will be useful to further explore the relationships between genotypes and pathogenesis of GBS and ureaplasma infection. In the study, we introduced novel data and tools into GBS and ureaplasma studies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based on the U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied the two published full genomes and exposed some new problems or possible future new research fields. In particular we found the two finished and one ongoing GBS genomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integrated studies of the two potential or conditional perinatal pathogens, from the viewpoint of evolution, would provide a new understanding angle of the pathogenesis of the two organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host (by losing most of its virulence genes); however, GBS tried to increase its invasive abilities (by getting more virulence genes) to fight against the human host attack.
2

Integrated study of group B streptococcus and human ureaplasmas � the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potential perinatal pathogens. Their relationships between genotypes and pathogenesis of GBS and ureaplasma infection were still not well understood, one of the reason is that both of them are still short of a very practical genotyping system. In the study, to solve the above problem we developed genotyping systems for the organisms (the second section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasma species (U. parvum and U. urealyticum). Further, based on the heterogeneity of ureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotyping systems showed that the genotyping systems were practical alternative assays for the conventional serotyping and they will be useful to further explore the relationships between genotypes and pathogenesis of GBS and ureaplasma infection. In the study, we introduced novel data and tools into GBS and ureaplasma studies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based on the U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied the two published full genomes and exposed some new problems or possible future new research fields. In particular we found the two finished and one ongoing GBS genomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integrated studies of the two potential or conditional perinatal pathogens, from the viewpoint of evolution, would provide a new understanding angle of the pathogenesis of the two organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host (by losing most of its virulence genes); however, GBS tried to increase its invasive abilities (by getting more virulence genes) to fight against the human host attack.
3

Integrated study of group B streptococcus and human ureaplasmas : the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potentialperinatal pathogens. Their relationships between genotypes and pathogenesis ofGBS and ureaplasma infection were still not well understood, one of the reason isthat both of them are still short of a very practical genotyping system. In the study,to solve the above problem we developed genotyping systems for the organisms (thesecond section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasmaspecies (U. parvum and U. urealyticum). Further, based on the heterogeneity ofureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotypingsystems showed that the genotyping systems were practical alternative assays forthe conventional serotyping and they will be useful to further explore therelationships between genotypes and pathogenesis of GBS and ureaplasmainfection. In the study, we introduced novel data and tools into GBS and ureaplasmastudies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based onthe U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied thetwo published full genomes and exposed some new problems or possible future newresearch fields. In particular we found the two finished and one ongoing GBSgenomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integratedstudies of the two potential or conditional perinatal pathogens, from the viewpointof evolution, would provide a new understanding angle of the pathogenesis of thetwo organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host(by losing most of its virulence genes); however, GBS tried to increase its invasiveabilities (by getting more virulence genes) to fight against the human host attack.
4

Characterization of Phosphoglycerate Kinase Expressed on the Surface of Group B Streptococcus

Boone, Tyler J Unknown Date
No description available.
5

Integrated study of group B streptococcus and human ureaplasmas : the paradigm shifts

Kong, Fanrong January 2004 (has links)
Group B streptococcus (GBS, S. agalactiae) and human ureaplasmas (U. parvumand U. urealyticum) are two clinically and phylogenetically related, potentialperinatal pathogens. Their relationships between genotypes and pathogenesis ofGBS and ureaplasma infection were still not well understood, one of the reason isthat both of them are still short of a very practical genotyping system. In the study,to solve the above problem we developed genotyping systems for the organisms (thesecond section). For human ureaplasmas, based on four genes/gene clusters (rRNAgene clusters, the elongation factor Tu genes, urease gene complexes and multiplebanded antigen genes), we designed many primer pairs suitable for developing species identification assays for the two newly established human ureaplasmaspecies (U. parvum and U. urealyticum). Further, based on the heterogeneity ofureaplasma multiple banded antigen gene (which contains species- and serovar-specific regions), we developed genotyping methods for each ureaplasma species.For GBS, based on three sets of molecular markers (capsular polysaccharidesynthesis gene clusters, surface protein antigen genes and mobile genetic elements),we developed a genotyping system. The primary evaluation of the genotypingsystems showed that the genotyping systems were practical alternative assays forthe conventional serotyping and they will be useful to further explore therelationships between genotypes and pathogenesis of GBS and ureaplasmainfection. In the study, we introduced novel data and tools into GBS and ureaplasmastudies especially from genomic- and bioinformatics-based molecular microbiology(the third section). For two newly established human ureaplasma species, based onthe U. parvum serovar-3 genome, and using the above four important genes/geneclusters, we exposed some interesting problems in the understanding of newureaplasma taxonomy especially in the post genomic era. For GBS, we studied thetwo published full genomes and exposed some new problems or possible future newresearch fields. In particular we found the two finished and one ongoing GBSgenomes were all non-typical and suggest that future genomic project had better have genetic population structure viewpoint. Finally, we suggested that integratedstudies of the two potential or conditional perinatal pathogens, from the viewpointof evolution, would provide a new understanding angle of the pathogenesis of thetwo organisms. Studies suggested that during coevolution, human ureaplasmas(especially U. parvum) became friendlier than their ancestors to their human host(by losing most of its virulence genes); however, GBS tried to increase its invasiveabilities (by getting more virulence genes) to fight against the human host attack.
6

Bioinformatic insights into the biosynthesis of the Group B carbohydrate in Streptococcus agalactiae

Sutcliffe, I.C., Black, G.W., Harrington, Dean J. 01 May 2008 (has links)
No / Streptococcus agalactiae is a major human and animal pathogen, most notable as a cause of life-threatening disease in neonates. S. agalactiae is also called the Group B Streptococcus in reference to the diagnostically significant Lancefield Group B typing antigen. Although the structure of this complex carbohydrate antigen has been solved, little is known of its biosynthesis beyond the identification of a relevant locus in sequenced S. agalactiae genomes. Analysis of the sugar linkages present in the Group B carbohydrate (GBC) structure has allowed us to deduce the minimum enzymology required to complete its biosynthesis. Most of the enzymes required to complete this biosynthesis can be identified within the putative biosynthetic locus. Surprisingly, however, three crucial N-acetylglucosamine transferases and enzymes required for activated precursor synthesis are not apparently located in this locus. A model for GBC biosynthesis wherein the complete polymer is assembled at the cytoplasmic face of the plasma membrane before translocation to the cell surface is proposed. These analyses also suggest that GBC is the major teichoic acid-like polymer in the cell wall of S. agalactiae, whereas lipoteichoic acid is the dominant poly(glycerophosphate) antigen. Genomic analysis has allowed us to predict the pathway leading to the biosynthesis of GBC of S. agalactiae.
7

Colonização de pacientes grávidas por Streptococcus agalactiae em Taguatinga, Distrito Federal, Brasil / Colonisation by group B streptococcus in pregnant patients in Taguatinga, Federal District, Brazil

Siqueira, Fabio [UNESP] 27 January 2017 (has links)
Submitted by FÁBIO SIQUEIRA null (fabiosqr@gmail.com) on 2017-02-02T16:15:56Z No. of bitstreams: 1 Tese Fábio Siqueira.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-06T15:51:30Z (GMT) No. of bitstreams: 1 siqueira_f_dr_bot.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) / Made available in DSpace on 2017-02-06T15:51:30Z (GMT). No. of bitstreams: 1 siqueira_f_dr_bot.pdf: 5157545 bytes, checksum: e3110e94c65818e724da50cfc84cb635 (MD5) Previous issue date: 2017-01-27 / Fundação de Ensino e Pesquisa em Ciências da Saúde (FEPECS) / Objetivo: verificar a prevalência do estreptococo do grupo B em gestantes de Taguatinga, Distrito Federal, Brasil. Desenho: Estudo transversal. Local: Taguatinga (Região metropolitana de Brasília), Distrito Federal, Brasil. Introdução: o estreptococo do Grupo B é responsável por infecções graves em neonatos, resultante da transmissão vertical por gestantes colonizadas nas regiões anal, perineal ou vaginal. A identificação das pacientes colonizadas e uso de profilaxia intraparto podem reduzir o risco de infeção neonatal Métodos: Estudo transversal em pacientes gestantes entre a 35 e 37ª. semana de gravidez. Foi coletado material das pacientes para identificação laboratorial do Estreptococo do grupo B. Também foram coletados dados epidemiológicos das pacientes como peso, altura, índice da massa corporal, uso de antibióticos durante a gravidez, comorbidades durante a gravidez (diabetes, doenças hipertensivas, hipotireoidismo), gemelaridade, entre outras. Resultados: a amostra foi composta de 501 gestantes e a prevalência para o estreptococo do grupo B foi de 14%. A média de idade foi de 29 anos e o índice de massa corporal de 30,7. Durante a gravidez 204 pacientes tiveram algum tipo de infecção e 201 foram usaram antibióticos, 95 foram diagnosticadas com diabetes melito gestacional e 74 com alguma doença hipertensiva. Conclusão: a prevalência encontrada não difere do verificado por outros autores. Dentre os fatores estudados nenhum manifestou-se como fator de risco ou de proteção para a colonização materna para o estreptococo do grupo B. / Objective: To verify the prevalence of group B streptococcus (GBS) in pregnant women in Taguatinga, Federal District, Brazil. Design: Cross-sectional study. Setting: Taguatinga (metropolitan region of Brasilia), Federal District, Brazil. Sample: 501 pregnant women Methods: This cross-sectional study was conducted in pregnant women between the 35th and 37th week of pregnancy. Samples were collected from patients for laboratory identification of GBS. Epidemiological data were also collected from patients, including weight, height, body mass index, use of antibiotics during pregnancy, pathologies during pregnancy (diabetes, hypertensive disease, hypothyroidism), and twin pregnancy. Main outcome measures: Presence or absence of GBS in pregnant women. Results: The sample was composed of 501 pregnant women, and the prevalence of GBS was 14%. The average age was 29 years, and the average body mass index was 30.7. During pregnancy, 204 patients had some kind of infection, 201 of them have used antibiotics, 95 were diagnosed with gestational diabetes mellitus, and 74 were diagnosed with some kind of hypertensive disease. Conclusion: The prevalence found does not differ from that verified by other authors. None of the studied factors was a risk or protection factor for maternal GBS colonization. / FEPECS: 064.000.052/2012
8

Colonização de pacientes grávidas por Streptococcus agalactiae em Taguatinga, Distrito Federal, Brasil

Siqueira, Fabio. January 2017 (has links)
Orientador: Adriano Dias / Resumo: Objetivo: verificar a prevalência do estreptococo do grupo B em gestantes de Taguatinga, Distrito Federal, Brasil. Desenho: Estudo transversal. Local: Taguatinga (Região metropolitana de Brasília), Distrito Federal, Brasil. Introdução: o estreptococo do Grupo B é responsável por infecções graves em neonatos, resultante da transmissão vertical por gestantes colonizadas nas regiões anal, perineal ou vaginal. A identificação das pacientes colonizadas e uso de profilaxia intraparto podem reduzir o risco de infeção neonatal Métodos: Estudo transversal em pacientes gestantes entre a 35 e 37ª. semana de gravidez. Foi coletado material das pacientes para identificação laboratorial do Estreptococo do grupo B. Também foram coletados dados epidemiológicos das pacientes como peso, altura, índice da massa corporal, uso de antibióticos durante a gravidez, comorbidades durante a gravidez (diabetes, doenças hipertensivas, hipotireoidismo), gemelaridade, entre outras. Resultados: a amostra foi composta de 501 gestantes e a prevalência para o estreptococo do grupo B foi de 14%. A média de idade foi de 29 anos e o índice de massa corporal de 30,7. Durante a gravidez 204 pacientes tiveram algum tipo de infecção e 201 foram usaram antibióticos, 95 foram diagnosticadas com diabetes melito gestacional e 74 com alguma doença hipertensiva. Conclusão: a prevalência encontrada não difere do verificado por outros autores. Dentre os fatores estudados nenhum manifestou-se como fator de risco ou de proteçã... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor
9

The impact of pH and nutrient stress on the growth and survival of Streptococcus agalactiae

Yang, Q., Porter, A.J., Zhang, M., Harrington, Dean J., Black, G.W., Sutcliffe, I.C. 17 April 2012 (has links)
No / Streptococcus agalactiae is a major neonatal pathogen that is able to colonise various host environments and is associated with both gastrointestinal and vaginal maternal carriage. Maternal vaginal carriage represents the major source for transmission of S. agalactiae to the foetus/neonate and thus is a significant risk factor for neonatal disease. In order to understand factors influencing maternal carriage we have investigated growth and long term survival of S. agalactiae under conditions of low pH and nutrient stress in vitro. Surprisingly, given that vaginal pH is normally <4.5, S. agalactiae was found to survive poorly at low pH and failed to grow at pH 4.3. However, biofilm growth, although also reduced at low pH, was shown to enhance survival of S. agalactiae. Proteomic analysis identified 26 proteins that were more abundant under nutrient stress conditions (extended stationary phase), including a RelE family protein, a universal stress protein family member and four proteins that belong to the Gls24 (PF03780) stress protein family. Cumulatively, these data indicate that novel mechanisms are likely to operate that allow S. agalactiae survival at low pH and under nutrient stress during maternal vaginal colonisation and/or that the bacteria may access a more favourable microenvironment at the vaginal mucosa. As current in vitro models for S. agalactiae growth appear unsatisfactory, novel methods need to be developed to study streptococcal colonisation under physiologically-relevant conditions.
10

Expression of the MtsA lipoprotein of Streptococcus agalactiae A909 is regulated by manganese and iron

Bray, B.A., Sutcliffe, I.C., Harrington, Dean J. 04 November 2008 (has links)
No / Metal ion acquisition and homeostasis are essential for bacterial survival, growth and physiology. A family of metal ion, ABC-type import systems have been identified in Gram-positive bacteria, in which the solute-binding proteins are predicted to be membrane-anchored lipoproteins. The prediction that the MtsA protein of Streptococcus agalactiae A909 is a lipoprotein was confirmed. The expression of MtsA was co-ordinately regulated by the presence of both manganese and ferrous ions suggesting that MtsA may be involved in the uptake of both these ions. MtsA was shown to be expressed at levels of ferrous ions known to be present in amniotic fluid, a growth medium for S. agalactiae during neonatal infection.

Page generated in 0.0612 seconds