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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.
31

Purification and characterization of CopR, a copper(II) dependent transcription factor

Khanal, Prakash 09 August 2019 (has links)
Transcription factors (TFs) are proteins that respond to a specific chemical signal and bind to DNA. In some bacteria, TFs control transition metal ion homeostasis by specifically binding with a particular metal ion or ions and then interacting with DNA. Although most first row metal ions are required as micronutrients for life, many of them can cause cellular damage or death if their concentrations are too high; this makes these TFs and their biological interactions excellent targets for drug development. The bacteria, Streptococcus pneumoniae is a pathogenic microorganism responsible for a range of diseases that target the young and the old, including pneumonia, meningitis, and bacteremia. Herein, we describe our efforts to study the Streptococcus pneumoniae TF responsible for copper(II) ion homeostasis. This thesis describes the classical biochemical techniques used to over-express and purify CopR. It also describes a series of preliminary characterization data associated with this novel copper(II)-dependent TF.
32

Síntese, caracterização e avaliação imunológica de conjugados do sorotipo 6B de Streptococcus pneumoniae à proteína A de superfície pneumocócica (PspA). / Synthesis, characterization and immunological evaluation of conjugates from Streptococcus pneumoniae serotype 6B and Pneumococcal Surface Protein A (PspA).

Lores, Lazara Elena Santiesteban 09 May 2016 (has links)
As vacinas conjugadas contra Streptococcus pneumoniae mostram-se eficazes na redução da doença pneumocócica, no entanto depois de sua introdução tem se verificado a substituição de sorotipos. Para evitar estes problemas o emprego de proteínas da própria bactéria como carreadoras tem sido usado. Neste trabalho a PspA foi conjugada ao sorotipo 6B de S. pneumoniae por dois métodos de conjugação. Inicialmente a PspA clado 1 e 3 foram purificadas, recuperando as proteínas com mais de 90% de pureza. A conjugação intermediada pelo agente ativador cloreto de 4-(4,6-dimetoxi-1,3,5-triazin-2-il-)-4-metilmorfolino (DMT-MM) permitiu rendimentos de Ps entre 20 e 30%, no entanto este tipo de conjugado não foi imunogênico resultando na não indução de anticorpos anti-PspA. Por outro lado a conjugação por aminação redutiva possibilitou obter rendimentos de Ps entre 50 e 60% e os conjugados induziram elevados títulos de anticorpos anti-PspA em camundongos Balb/c, que foram capazes de promover a fagocitose da bactéria; no entanto, a resposta de anticorpos anti-Ps 6B foi baixa. / Conjugate vaccines against Streptococcus pneumonaie have had an important public health benefit; nevertheless after its introduction it has been observed a serotype replacement. To solve this problems conjugate vaccines using pneumococcal surface proteins as carriers has been studied. In this work, Pneumococal surface protein A (PspA) was employed as a carrier protein, conjugated to serotype 6B. Initially PspA clade 1 and PspA clade 3 were purified; both proteins were recovered with more than 90% purity. The conjugation mediated by the activating agent 4- (4,6-dimethoxy-1,3,5-triazin-2-yl -) - 4-methylmorpholine chloride(DMT-MM) allowed Ps yields between 20 and 30%, however this conjugation chemistry had a negative impact on the immunogenicity of the protein. On the other hand conjugation by reductive amination led to Ps yields between 50 and 60% and induced high anti-PspA antibodies titers in Balb /c mice that were able to promote phagocytosis of the bacterium; however, polysaccharide 6B induced low antibody titers.
33

A study of the factors affecting parental decisions regarding streptococcus pneumoniae vaccination

Han, Shiang-Ru 29 August 2012 (has links)
With regard to infectious diseases, the most economical, direct, and efficient way to prevent them is timely inoculation and a comprehensive policy of vaccination. Such steps not only reduce the overall mortality rate, but also lessen a patient¡¦s susceptibility to serious complications once infected, and therefore their length of hospital stay. It is the foundation of disease prevention in all countries, and should be the primary focus of every public health department. This survey is based on a health belief model and a self-constructed questionnaire. Its sample base are parents whose children have visited one of two local hospitals, each of which is in a different administrative region. A total of 350 questionnaires were distributed. Recoveries were 270, of which 237 were useable. The effective response rate, therefore, is 67.7%. The useable recoveries were analyzed by SPSS, 17th edition, and verified and assumed by mean, standard deviation, t-test, one-way ANOVA, Pearson correlation analysis and Logistic regression analysis. The most influential factors on parents¡¦ decision whether or not to accept streptococcus pneumoniae vaccination (SPV) were as follows: 1.The greater the understanding of SPV and its policy, the greater the number of vaccinations 2.The perceived importance of good health 3. Age variability 4. The interrelationship between the perception and the policy of vaccination, the benefits of - and barriers to ¡V action, and the virulence and severity of the disease The results of this research suggest the public perception of SPV is the most important factor governing its efficacy. It is recommended, therefore, that public health departments campaign for SPV in a variety of different ways,( e.g. in newspapers and magazines, on TV, at pediatric clinics, at health centers, etc.) in order to establish a free and open flow of information to the public at large. It is in the hope of reducing the current mortality rate, length and cost of hospital stay and the serious complications arising from infection, that we offer the following data as reference for future planning.
34

The identification and distribution of multidrug resistance in Streptococcus pneumoniae in Washington State /

Luna, Vicki Ann, January 1999 (has links)
Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 143-181).
35

Impacto da vacina pneumocócica conjugada 10-valente (PCV10) na meningite pneumocócica na região metropolitana de Salvador, Bahia

Silva Junior, Jailton de Azevedo January 2015 (has links)
Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-05-11T14:07:03Z No. of bitstreams: 1 Jailton_Azevedo Silva Junior. Impacto da vacina...2015.pdf: 2256825 bytes, checksum: 6da623ba97a2d68604f3b4a098585b07 (MD5) / Approved for entry into archive by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2016-05-11T14:07:15Z (GMT) No. of bitstreams: 1 Jailton_Azevedo Silva Junior. Impacto da vacina...2015.pdf: 2256825 bytes, checksum: 6da623ba97a2d68604f3b4a098585b07 (MD5) / Made available in DSpace on 2016-05-11T14:07:15Z (GMT). No. of bitstreams: 1 Jailton_Azevedo Silva Junior. Impacto da vacina...2015.pdf: 2256825 bytes, checksum: 6da623ba97a2d68604f3b4a098585b07 (MD5) Previous issue date: 2015 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / INTRODUÇÃO: Em 2010, a vacina conjugada 10-valente (PCV10) foi incorporada ao programa nacional de imunizações (PNI) brasileiro. Este imunobiológico confere imunização contra os dez principais tipos capsulares de Streptococcus pneumoniae, patógeno responsável por diversas manifestações clínicas e com elevada contribuição nas taxas de incidência e mortalidade por meningite, que é a condição clínica mais grave. OBJETIVO: O presente estudo teve como objetivo avaliar o impacto da PCV10 na epidemiologia da meningite pneumocócica na região metropolitana de Salvador (RMS) Bahia, comparando o período anterior (2008-2010) e posterior (2011-2013) a sua utilização, bem como realizar uma caracterização molecular minuciosa a partir de uma série histórica (1996-2012) entre os isolados resistentes a penicilina (PNSSP com CIM≥ 0,125 μg/mL) e para os sorotipos não-vacinais (2008-2012). MATERIAL E MÉTODOS: Foram incluídos todos casos de meningite pneumocócica confirmados laboratorialmente no período entre 1996 a 2013. Taxas de incidência para a Salvador e RMS foram calculadas com base nos dados populacionais do IBGE/2010. A determinação do tipo capsular foi realizada através da técnica de Multiplex-PCR e/ou reação de Quellung. A sensibilidade a nove antimicrobianos foi testada através das técnicas disco-difusão, microdiluição e E-test. Para caracterizar o perfil molecular foram aplicadas as técnicas de genotipagem de PFGE e MLST. RESULTADOS: Um total de 939 casos de meningite pneumocócica foram identificados no período de 1996- 2013, sendo que 70 casos ocorrem entre 2011 a 2013 (período pós-vacinal). A incidência de meningite pneumocócica em todas as faixas etárias na RMS reduziu de 0,70 casos/100.000 habitantes para 0,59 casos/100.000 habitantes considerando o período de três anos antes e após a vacinação com PCV10 [p< 0,05; RR IC 95%: 1,46 (1,03-2,05)]. Esta redução foi significativa na faixa etária de 0-2 anos e nos casos por sorotipos relacionados à PCV10. Não houve aumento significativo de casos por sorotipos não vacinais nesta casuística, apesar do surgimento de casos por sorotipos não-vacinais não detectados anteriormente na série histórica de MP (10F, 21, 22F, 15A e 24F). Os isolados resistentes à penicilina analisados na série histórica se restringiram a 13 sorotipos, entre os quais: 14 (45,1 %; 78/173), 23F (19,1%; 33/173), 6B (14,4 %; 25/173), 19F (9,2 %; 16/173) e 19A (5,2 %; 9/173). 94% dos casos nãosusceptíveis à penicilina (PNSSP) foram de sorotipos vacinais. Os grupos clonais caracterizados pelo PFGE/MLST predominantes ao longo dos anos foram representados pelo sorotipo 14, denominado grupo A/ST 66 [35,3 % (61/173)] e grupo GK/ST 156 [4.6 % (8/173)], este último associado com níveis elevados de resistência a penicilina e ceftriaxona. Não foram detectados grupos clonais emergentes associados a tipos capsulares não-vacinais. CONCLUSÕES: Estes achados sugerem que a introdução da PCV10 modificou a epidemiologia da meningite pneumocócica na população estudada. / INTRODUCTION: In 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced into the Brazilian national immunization program (NIP). This immunobiological provides immunization against the main ten capsular types of Streptococcus pneumoniae, the pathogen responsible for different clinical manifestations and high contribution in the incidence and mortality from meningitis, which is the most severe clinical condition. OBJECTIVE: This study aimed to evaluate the impact of PCV10 in the epidemiology of pneumococcal meningitis in the metropolitan area of Salvador (RMS) Bahia, comparing the previous (2008-2010) and after (2011-2013) periods its use, as well as conduct a thorough molecular characterization from a historical series (1996-2012) among isolates resistant to penicillin (PNSSP with CIM≥ 0.125 g / ml) and nonvaccine serotypes (2008-2012). MATERIAL AND METHODS: We included all cases of pneumococcal meningitis laboratory confirmed for the period 1996 to 2013. Incidence rates for Salvador and RMS were calculated based on population data from IBGE/2010. The capsular type determination was performed by multiplex PCR and/or Quellung reaction. Isolates Nine antibiotics were tested by disk-diffusion test, broth micro-dilution and E-test. To characterize the molecular profiling techniques were applied genotyping PFGE and MLST. RESULTS: A total of 939 cases of pneumococcal meningitis were identified during 1996-2013 period, with 70 cases occurring between 2011-2013 (post-vaccination period). The incidence of pneumococcal meningitis in all age groups in the RMS decreased from 0.70 cases / 100,000 inhabitants to 0.59 cases / 100,000 inhabitants considering the three-year period before and after vaccination with PCV10 [p <0.05; RR 95% CI: 1.46 (1.03 to 2.05)]. This reduction was significant in the age group 0-2 years and in cases by serotypes related to PCV10. There was no significant increase in cases by serotypes not vaccine in this series, despite the emergence of cases by serotypes not-vaccine previously undetected in the historical series of MP (10F, 21, 22F, 15A and 24F). The penicillin resistant isolates analyzed the historical series were restricted to 13 serotypes, including: 14 (45.1%; 78/173), 23F (19.1%; 33/173), 6B (14.4%; 25/173), 19F (9.2%, 16/173) and 19A (5.2%, 9/173). 94% of nonsusceptible to penicillin cases (PNSSP) were vaccine serotypes. Clonal groups characterized by PFGE / MLST predominant over the years have been represented by serotype 14, group called A / ST 66 [35.3% (61/173)] and Group GK / TS 156 [4.6% (8/173) ], the latter associated with elevated levels of penicillin and ceftriaxone resistance. Not were detected emerging clonal groups associated with capsular types non-vaccination. CONCLUSIONS: These findings suggest that the introduction of PCV10 changed the epidemiology of pneumococcal meningitis in the population studied.
36

Síntese, caracterização e avaliação imunológica de conjugados do sorotipo 6B de Streptococcus pneumoniae à proteína A de superfície pneumocócica (PspA). / Synthesis, characterization and immunological evaluation of conjugates from Streptococcus pneumoniae serotype 6B and Pneumococcal Surface Protein A (PspA).

Lazara Elena Santiesteban Lores 09 May 2016 (has links)
As vacinas conjugadas contra Streptococcus pneumoniae mostram-se eficazes na redução da doença pneumocócica, no entanto depois de sua introdução tem se verificado a substituição de sorotipos. Para evitar estes problemas o emprego de proteínas da própria bactéria como carreadoras tem sido usado. Neste trabalho a PspA foi conjugada ao sorotipo 6B de S. pneumoniae por dois métodos de conjugação. Inicialmente a PspA clado 1 e 3 foram purificadas, recuperando as proteínas com mais de 90% de pureza. A conjugação intermediada pelo agente ativador cloreto de 4-(4,6-dimetoxi-1,3,5-triazin-2-il-)-4-metilmorfolino (DMT-MM) permitiu rendimentos de Ps entre 20 e 30%, no entanto este tipo de conjugado não foi imunogênico resultando na não indução de anticorpos anti-PspA. Por outro lado a conjugação por aminação redutiva possibilitou obter rendimentos de Ps entre 50 e 60% e os conjugados induziram elevados títulos de anticorpos anti-PspA em camundongos Balb/c, que foram capazes de promover a fagocitose da bactéria; no entanto, a resposta de anticorpos anti-Ps 6B foi baixa. / Conjugate vaccines against Streptococcus pneumonaie have had an important public health benefit; nevertheless after its introduction it has been observed a serotype replacement. To solve this problems conjugate vaccines using pneumococcal surface proteins as carriers has been studied. In this work, Pneumococal surface protein A (PspA) was employed as a carrier protein, conjugated to serotype 6B. Initially PspA clade 1 and PspA clade 3 were purified; both proteins were recovered with more than 90% purity. The conjugation mediated by the activating agent 4- (4,6-dimethoxy-1,3,5-triazin-2-yl -) - 4-methylmorpholine chloride(DMT-MM) allowed Ps yields between 20 and 30%, however this conjugation chemistry had a negative impact on the immunogenicity of the protein. On the other hand conjugation by reductive amination led to Ps yields between 50 and 60% and induced high anti-PspA antibodies titers in Balb /c mice that were able to promote phagocytosis of the bacterium; however, polysaccharide 6B induced low antibody titers.
37

Emerging antimicrobial resistance in Streptococcus pneumoniae

Ho, Pak-leung., 何柏良. January 2008 (has links)
published_or_final_version / Medicine / Master / Doctor of Medicine
38

Comparative genomic analyse by microarray technology of pneumococci with different potential to cause disease.

Browall, Sarah January 2007 (has links)
<p>Streptococcus pneumoniae is a gram-positive bacterium that can be found in both healthy carriers as well as in people that have developed disease. One of the major virulence factors of pneumococci is their polysaccharide capsule. Based on the capsule that surrounds the bacteria, pneumococci are divided into at least 90 different serotypes. Some serotypes seem to be more related to virulence than others.</p><p>I have with comparative genome hybridization microarray technique, studied gene differences between 18 epidemiological well-characterised pneumococcal strains with different potential to cause disease. A microarray chip based on two sequenced pneumococcal genomes, R6 and TIGR4, has already been designed. According to Hierarchical clustering, both the serotype and the genetic type as assessed by MLST (sequence type or ST) seem to have impact on the relationship of clinical isolates. Most clinical isolates of the same serotype are clustered together except for serotype 14 isolates that seem to be more divergent. Further more the number of genes that are divergent between clinical isolates compared to R6 and TIGR4 differ from 65 to 289. Preliminary results indicate that although there is diversity among clinical isolates some are more closely related to each other then others. Absent genes seem to be evenly distributed among all 18 clinical isolates tested but hypothetical genes and genes for cell envelope are two groups of role categories that are absent to the largest extent in all isolates.</p><p>According to results from microarray analysis, a gene region, spr0112-spr1015- is present in all type 9V isolates and absent in many isolates of serotype 14, 19F and 7F. These results have been confirmed by polymerase chain reaction (PCR).</p><p>Conserved genes in a region around the capsule genes have been sequenced to identify marker genes for a capsulular switch between serotype 9V and 14. Preliminary results of the sequencing showed that as much as 750kb might have been transferred in the event of capsular switch.</p>
39

Contributions to an understanding of community-acquired pneumonia

Feldman, Charles 28 February 2012 (has links)
DSc (Med), Faculty of Health Sciences, University of the Witwatersrand, 2009.
40

Comparative proteomic analyses of clinical Streptococcus pneumoniae isolates from invasive and non-invasive sites

Bittaye, Mustapha January 2018 (has links)
Streptococcus pneumoniae is a highly diverse and adaptable opportunistic pathogen that can infect and colonise different niches within the human host to cause a wide range of invasive disease (sepsis and meningitis) and noninvasive disease (pneumonia, otitis media and sinusitis). The molecular mechanisms that contribute to the different patterns of pneumococcal infection remain largely unknown. This thesis aims to determine the physiological and proteomic responses that allow the pneumococcus to survive and adapt to invasive and non-invasive sites. The comparative proteomic analyses of clinical S. pneumoniae isolates recovered from blood cultures (classified as invasive site isolates) and mucosal surfaces such as sputum, skin and ear swabs (classified as non-invasive site isolates) was initiated. The pneumococci were grown in vitro under standard conditions and the total cellular bacterial proteins extracted and analysed using both gel based and non-gel based proteomic approaches. Analysis of the pneumococcal isolates by two-dimensional polyacrylamide gel electrophoresis (2DGE) revealed that a high degree of heterogeneity existed between the pneumococcal isolates particularly among isolates in the invasive site isolates. Differential patterns of protein synthesis were observed that discriminated the pneumococcal isolates according to their sites of isolation. These were proposed to be associated with the bacterial adaptation to invasive and non-invasive sites of infection. Mass spectrometry was used to identify selected significant (ANOVA, p < 0.05) protein spots, which were further categorised into functional groups by Gene Ontology analysis. An extension of the 2DGE data using an integrated approach comprising bioinformatics, surfome analysis and a shotgun proteomic workflow provided a comprehensive qualitative and quantitative analyses of the pneumococcal intracellular and cell-surface proteomes. Proteins potentially involved in pneumococcal niche-specific adaptation and surface proteins with potential for further investigation and inclusion in the pipeline of vaccine candidates were identified. Quantitative regulation of proteins involved in energy metabolism, genetic competence, stress response, surface adhesion and virulence were considered important for pneumococcal adaptation to invasive and non-invasive sites. The anatomical sites colonised by the pneumococcus vary in their V availability for iron. The 2DGE method was also used on selected pneumococcal isolates from the two sites of infection to define the proteome variability linked to the effect of iron starvation that may contribute to the different disease outcomes associated with pneumococcal infections. The iron restricted condition was generated by cation depletion of the growth medium using Chelex-100. Quantitative differences in protein abundance were demonstrated that correlated with pneumococcal adaptation to iron restriction. The identification of selected significant spots by liquid chromatography-mass spectrometry and systems biology analysis of the identified proteins contributed to the elucidation of the molecular mechanisms underlying pneumococcal survival under iron limitation. The expression/repression of proteins functionally associated with metal ion binding, oxidative stress response, translation and virulence mainly constituted the pneumococcal adaptive responses to growth under conditions of limited iron availability. The data presented in this thesis extended our understanding of the molecular events underlying pneumococcal physiological adaptation and provide the basis of future work in this area.

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