Rozprawy doktorskie na temat „Streptococcus pyogenes”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Streptococcus pyogenes”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Berge, Andreas. "Molecular analysis of Streptococcus pyogenes and its interactions with the human host". Lund : Lund University, 1997. http://catalog.hathitrust.org/api/volumes/oclc/68945123.html.
Pełny tekst źródłaThern, Anette. "Interactions between Streptococcus pyogenes and the human immune system with special reference to C4b-binding protein /". Lund : Dept. of Medical Microbiology, Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/39224761.html.
Pełny tekst źródłaZhang, Meng. "Proteomic analysis of streptococcus pyogenes". Thesis, Northumbria University, 2007. http://nrl.northumbria.ac.uk/842/.
Pełny tekst źródłaSiou, GeÌrard Paul Serge. "Streptococcus pyogenes interactions with human tonsils". Thesis, University of Newcastle upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424082.
Pełny tekst źródłaDesai, Meeta. "Molecular epidemiological typing of Streptococcus pyogenes". Thesis, Open University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299021.
Pełny tekst źródłaBroglia, Laura. "Regulating with ribonucleases in Streptococcus pyogenes". Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21573.
Pełny tekst źródłaBacteria have developed a plethora of strategies to cope with constantly changing environmental conditions, including post-transcriptional regulatory mechanisms. With this regard, regulation of gene expression can be achieved by either the rapid removal or stabilization of RNA molecules by ribonucleases (RNases). RNases exhibit species-specific effects on gene expression, bacterial physiology and different strategies of target recognition, indicating that our understanding of the RNA degradation machinery is not yet complete. The aim of this thesis was to investigate the features and functions of endoRNase Y from the strict human pathogen Streptococcus pyogenes. To gain insight into the role and specificity of this RNase, we identified RNase Y cleavage positions (i.e. targetome) genome-wide by RNA sequencing. Next, to investigate the RNA degradation pathway depending on RNase Y, we compared the RNase Y targetome with the ones of the three 3′-to-5′ exoribonuclease (exoRNases), namely PNPase, YhaM and RNase R. Finally, to dissect the requirements for RNase Y processing and to decipher the role of RNase Y in virulence gene regulation, we studied the impact of RNase Y on speB mRNA, encoding a major virulence factor. This study reveals that RNase Y preferentially cleaves RNAs downstream of a guanosine and for the first time we were able to show that the presence of a guanosine residue is essential for the processing of speB mRNA, in vivo. Although RNase Y cleaves the speB mRNA, our data underpin a model in which RNase Y-mediated regulation of speB expression occurs at the transcriptional level. Using the targetome comparative approach, we demonstrated that RNase Y initiates RNA decay in S. pyogenes and that the RNase Y-generated RNA 3′ ends are usually further trimmed by PNPase and/or YhaM. Overall, these findings increase our understanding of RNase Y functionality and RNA degradation in Gram-positive bacteria.
Becherelli, Marco <1979>. "Functional characterization of Streptococcus pyogenes pili". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/3015/1/Becherelli_Marco_Tesi.pdf.
Pełny tekst źródłaBecherelli, Marco <1979>. "Functional characterization of Streptococcus pyogenes pili". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2010. http://amsdottorato.unibo.it/3015/.
Pełny tekst źródłaMcNamara, Case W. "Molecular analysis of Streptococcus pyogenes M1 protein". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2006. http://wwwlib.umi.com/cr/ucsd/fullcit?p3230034.
Pełny tekst źródłaTitle from first page of PDF file (viewed November 17, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
Dixon, Emma Victoria. "Mechanisms of immunoglobulin deactivation by Streptococcus pyogenes". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:ec80e3f9-0c73-4d39-bc68-c39b927365d4.
Pełny tekst źródłaCaswell, Clayton Christopher. "The SCL1 protein of Streptococcus pyogenes a structure-function analysis /". Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=6026.
Pełny tekst źródłaTitle from document title page. Document formatted into pages; contains xi, 190 p. : ill. (some col.). Includes abstract. Includes bibliographical references.
Darenberg, Jessica. "Streptococcus pyogenes infections and toxic shock syndrome : molecular epidemiology and immunotherapy /". Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-676-X/.
Pełny tekst źródłaMeinhart, Anton. "Kristallstrukturanalyse des e, z-Proteinkomplexes [Epsilon, zeta-Proteinkomplexes], kodiert vom Plasmid pSM19035 aus Streptrococcus pyogenes". [S.l.] : [s.n.], 2001. http://www.diss.fu-berlin.de/2001/188/index.html.
Pełny tekst źródłaLuis, Philippe Renard Vincent. "Le TDR modifie-t-il la pratique des médecins généralistes d'Ile de France ?" Créteil : Université de Paris-Val-de-Marne, 2006. http://doxa.scd.univ-paris12.fr:80/theses/th0240166.pdf.
Pełny tekst źródłaRussell, Hugh Hayden. "Molecular basis of epithelial internalisation of Streptococcus pyogenes". Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423540.
Pełny tekst źródłaLe, Rhun Anaïs. "Multifaceted RNA-mediated regulatory mechanisms in Streptococcus pyogenes". Doctoral thesis, Umeå universitet, Molekylär Infektionsmedicin, Sverige (MIMS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111090.
Pełny tekst źródłaSethman, Chad Robert. "Attachment of Streptococcus pyogenes to Host Epithelial Cells". Miami University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=miami1071776892.
Pełny tekst źródłaTedde, Vittorio. "Zinc uptake in Streptococcus pyogenes: characterisation of adcA". Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3422118.
Pełny tekst źródłaStreptococcus pyogenes (detto anche Streptococco di gruppo A, GAS) è un batterio Gram-positivo capsulato, adattato ad infettare l’uomo. I ceppi di GAS esprimono diversi fattori di virulenza che possono essere esposti sulla superficie esterna o secreti fuori dalla cellula. Tra i fattori di virulenza, i Superantigeni (SAGs) sono sicuramente tra i più nocivi per l’ospite. Uno studio recente ha dimostrato che in vitro SpeI, un superantigene secreto da GAS, interagisce con AdcA a Lmb, due proteine che trasportano lo zinco. In particolare, AdcA appartiene al trasportatore ad alta affinità Adc, che è coinvolto nell’adesione, nella competenza e nel trasporto dello zinco. Questo metallo è un microelemento essenziale per tutti gli organismi viventi, ma poiché possiede una elevata tossicità, le cellule devono regolare finemente la sua concentrazione intracellulare. In questo lavoro di tesi è stato studiato il ruolo di AdcA nel trasporto dello zinco in GAS. Per questo studio sono stati generati tre mutanti indipendenti nel ceppo MGAS5005, caratterizzandone il loro fenotipo. I mutanti sono stati ottenuti mediante l’uso del vettore termosensibile pJRS233. La delezione del gene adcA in Streptococcus pneumoniae comporta una notevole diminuzione della competenza, quindi la complementazione è stata ottenuta trasformando il mutante parziale, cioè l’ “eterozigote” intermedio che contiene sia l’allele wild type che quello mutato. L’assenza del trasportatore dello zinco influisce sulla capacità di importare lo zinco dal terreno di coltura e sulla suscettibilità alla mancanza di zinco. I mutanti ΔadcA mostrano chiaramente una maggiore sensibilità alla deprivazione di zinco se comparati con il ceppo wild type. La complementazione di uno dei mutanti riporta il fenotipo del mutante a quello del ceppo wild type. Quando il mutante è cresciuto in presenza di una concentrazione inibente del chelante TPEN, la crescita è ristabilita dalla aggiunta di zinco o di manganese. Questo probabilmente significa che il trasporto di questi due metalli può avvenire tramite l’altro trasportatore Lmb, codificato all’interno dell’operone lmb-htpA. Di conseguenza, l’espressione di Lmb e HtpA è stata analizzata tramite Western blot in condizioni di crescita diverse. Nelle cellule wild type AdcA è sempre espresso ad alti livelli, invece Lmb e HtpA sono espresse ad alti livelli solo nel terreno di coltura depleto di zinco. Questo risultato avvalora il concetto che AdcA è omologo da un punto di vista funzionale a ZnuA, il maggior trasportatore ad alta affinità dello zinco in molti batteri, e come ZnuA ha il compito del reclutamento dello zinco in molte condizioni.
Smeesters, Pierre. "Epidémiologie, pathogénie et prise en charge des infections à Streptococcus pyogenes touchant les enfants de Bruxelles et de Brasília". Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210620.
Pełny tekst źródłaPour mieux évaluer ces variations, nous avons mené une analyse prospective de l’épidémiologie clinique et moléculaire d’isolats de GAS provenant d’enfants présentant une infection à GAS, simultanément en deux localisations géographiques différentes (Bruxelles et Brasília, Brésil).
Un des points importants de notre étude a été la mise en évidence de la diversité génétique de la protéine M des isolats belges et brésiliens. Alors que de nombreux emm-types différents sont retrouvés à Brasília (48 emm-types sur 128 isolats), ceux retrouvés à Bruxelles sont relativement peu nombreux (20 emm-types sur 200 isolats) et sont ceux communément retrouvés dans les pays industrialisés. Afin de mieux comprendre les bases moléculaires de cette différence, une analyse phylogénétique basée sur la quasi-totalité de la séquence de la protéine M exposée à la surface de la bactérie a été réalisée. Cette analyse a permis de montrer que les emm-types belges sont génétiquement éloignés les uns des autres alors que les emm-types brésiliens sont génétiquement plus proches. De manière intéressante, cette analyse a montré que les souches belges présentent une grande diversité au niveau de la région de la protéine M dite ‘constante’. En conséquence, la diversité génétique globale des protéines M belges et brésiliennes est similaire, mais elle se situe dans des régions différentes de la protéine M, ce qui pourrait indiquer l’existence de pressions de sélection différentes entre les deux pays. D’un point de vue vaccinal, ces résultats indiquent qu’un vaccin dirigé contre certaines des parties constantes de M présenterait une bonne couverture théorique dans les deux pays. Par contre, le vaccin 26-valent, en cours d’évaluation clinique, aurait une couverture théorique de 76% à Bruxelles et de 32% à Brasília.
Notre analyse phylogénétique a également permis de montrer que la non-sensibilité à la ciprofloxacine (observée dans 22,5 % et 9% des souches belges et brésiliennes respectivement) survient dans des souches génétiquement éloignées, contrairement à ce qui est proposé actuellement dans la littérature. De plus, nous avons mis en évidence un polymorphisme au sein des gènes codant les topoisomérases cibles de la ciprofloxacine. L’identification de mutations responsables du phénotype de non-sensibilité nécessite par conséquent une confirmation expérimentale.
Les manifestations cliniques sont assez différentes entre Bruxelles et Brasília. Les infections cutanées sont beaucoup plus fréquentes à Brasília. De manière intéressante au Brésil, des souches de GAS présentant un tropisme cutané sont isolées du pharynx. Ces souches ‘cutanées’ pourraient avoir acquis des déterminants génétiques leur permettant de se développer dans des tissus pharyngés. De plus, ces résultats pourraient remettre en question le postulat que seules les souches de tropisme pharyngé sont impliquées dans le développement du RAA. D’autres études épidémiologiques dans des pays où le RAA est endémique devront être réalisées afin de préciser nos résultats et de mieux comprendre les mécanismes moléculaires menant au développement du RAA.
Cependant, étant donné la prévalence du RAA et l’accès limité au diagnostic microbiologique des pharyngites dans le réseau public de soins au Brésil, nous avons développé un score clinique permettant de limiter les traitements antibiotiques chez les enfants probablement atteints de pharyngites virales. L’utilisation de ce score permettrait de réduire le nombre de prescriptions antibiotiques dans les pharyngites de l’enfant de 41 à 55% à Brasília.
Le choc toxi-infectieux est une pathologie relativement rare et le RAA n’est quasi plus décrit dans les pays développés. Cependant, deux nourrissons ont présenté un choc toxi-infectieux suivi d’un RAA (HUDERF, Bruxelles). A notre connaissance, cette association clinique n’a jamais été décrite. L’analyse de ces deux cas du point de vue de la virulence bactérienne a révélé la présence de nombreux gènes de facteurs de virulence, portés par des phages et différents dans les deux souches. Nos résultats illustrent la complexité de la relation hôte-pathogène.
La capacité des bactéries à s’adapter à leurs hôtes et à causer des pathologies dépend de nombreux facteurs, qui varient d’un isolat à l’autre, et dont l’importance varie d’un hôte à l’autre. Notre travail a permis d’exemplifier la diversité génétique des GAS, aussi bien au niveau du gène emm qu’au niveau des facteurs de virulence, et de l’implication de ceux-ci dans le développement de pathologies streptococciques rares.
Doctorat en Sciences médicales
info:eu-repo/semantics/nonPublished
Cunningham, Cynthia A. "Induction of myosin cross-reactive antibody and cytolytic T cell responses in mice with Streptococcus pyogenes". Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1530.
Pełny tekst źródłaMalerba, Mariangela. "The immunomodulatory role of epidermal hepcidin in infectious condition". Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2166&f=13318.
Pełny tekst źródłaHepcidin, first discovered as an antimicrobial peptide, is now considered as the key iron regulatory hormone, inhibiting duodenal iron absorption and iron recycling by macrophages. Hepcidin expression is induced by iron accumulation and infection/inflammation while diminished in situations of iron needs. Hepcidin, as suggested by its name, is mainly expressed in the liver (Hep- for Hepatic) but also at low levels by many other cells. Our team has demonstrated that hepatic hepcidin is sufficient to ensure the systemic iron homeostasis in basal conditions; suggesting that extra-hepatic hepcidin could play local roles in pathophysiological conditions. Hepcidin contains 4 disulfide bonds with β-sheet fold and positively charged residues at the surface, showing close structural similarity to beta-defensins, a subfamily of antimicrobial peptides (AMP). AMPs are small proteins with antimicrobial activities but also immunomodulatory functions (chemotaxis, ...). Because hepcidin possesses disulfide bridges, resembling the intramolecular disulfide bonds critical for the function of chemokine proteins, we investigated the direct chemoattractant potential of hepcidin. We observed that human hepcidin shares structural similarities with the human CXCL1 homologue and demonstrated that hepcidin triggers neutrophil migration in vitro with a bell-shaped dose response curve, characteristic of chemokines. Taking advantage of in vivo bioluminescence assay, we confirmed that SC injection of hepcidin causes neutrophil recruitment in vivo. These results highlight a new immunomodulatory role of this AMP. Epithelia, such as intestine and skin, are the main source of AMPs. However, expression of hepcidin and its functional role as AMP in these tissues has never been studied. Therefore, I specifically investigated this aspect in the skin, using a model of group A streptococcal (GAS) subcutaneous (SC) infection. These gram-positive bacteria commonly colonize skin and are responsible for a wide range of both skin and invasive infections causing more than 500,000 deaths per year. The first host immune effectors encountered by GAS are endogenous AMP produced by epithelial cells and by circulating immune cells (neutrophils and macrophages) so GAS represents a tremendous model to study hepcidin function as antimicrobial peptide in the skin. We specifically deleted hepcidin in keratinocytes (Hepc KOker) and in myeloid cells (Hepc KOmyel). Interestingly, while Hepc KOmyel and WT littermates showed the same number of bacteria at local and systemic level, we found that Hepc KOker mice present a worse outcome after infection than WT littermates, with a significantly higher number of bacteria at the lesion site and a stronger systemic spread of infection. We observed that hepcidin has neither bacteriostatic nor bacteriolytic effect against GAS in vitro and that both WT and Hepc KOker primary keratinocytes displayed the same bactericidal activity. Interestingly, we found that hepcidin promotes keratinocyte secretion of CXCL1, a key neutrophil chemokine, in vitro. Consistently, both the amount of CXCL1 and the number of neutrophils recruited at the site of infection was lower in Hepc KOker mice compared to WT littermates. Moreover, CXCL1 SC injections rescue the phenotype, confirming that the invasiveness observed in Hepc KOker is specifically caused by the absence of hepcidin-mediated CXCL1 production. Finally, we demonstrated that injections of exogenous hepcidin prevents the infection spread. These results highlight a new protective role of epidermal hepcidin against GAS infection, through modulation of neutrophil recruitment and suggest that hepcidin could represent a novel approach for therapy of GAS infections
Beck, Isabel L. "Tolérance à la pénicilline G de souches de "Streptococcus pyogenes" isolées au cours d'angines aigue͏̈s de l'enfant". Paris 5, 1993. http://www.theses.fr/1993PA05P199.
Pełny tekst źródłaGaleas, Pena Trilce Michelle. "Thermoregulation of capsule production of Streptococcus pyogenes strain HSC5 /". Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967978671&sid=7&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Pełny tekst źródłaDelgado, Giselle M. "SIAA and Neat2 Heme Binding Proteins from Streptococcus Pyogenes". Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/24.
Pełny tekst źródłaCalusni, Ana Lucia Roscani. "Interação entre o Streptococcus pyogenes e a hemoglobina S". [s.n.], 1994. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316745.
Pełny tekst źródłaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-07-19T08:31:44Z (GMT). No. of bitstreams: 1 Calusni_AnaLuciaRoscani_M.pdf: 1715301 bytes, checksum: acd3974eacbc813ea7e1416eeec145b7 (MD5) Previous issue date: 1994
Mestrado
Genetica
Mestre em Ciências Biológicas
LE, BOUGUENEC-BRIVE CHANTAL. "Etude d'un element genetique mobile (tn3701) chez streptococcus pyogenes". Paris 7, 1989. http://www.theses.fr/1989PA077082.
Pełny tekst źródłaWeinstein, Kathryn Elizabeth. "Generation of Diversity During the Survival of Streptococcus pyogenes". Diss., Temple University Libraries, 2010. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/105846.
Pełny tekst źródłaPh.D.
Streptococcus pyogenes is a human-specific pathogen that can cause a wide variety of diseases. These diseases range from the relatively mild pharyngitis and impetigo to invasive diseases such as necrotizing fasciitis to post-streptococcal sequelae such as rheumatic heart disease. The bacteria are frequently carried asymptomatically and may cause recurrent disease. Corresponding with their etiologic variation amongst diseases, clinical isolates demonstrate diverse virulence factor expression and random genetic mutations. In these studies, we examine the role of intracellular residence during survival as a niche for the diversification of S. pyogenes. Survival was previously studied using two in vitro systems: long-term stationary phase survival in culture and survival within epithelial cells in the presence of extracellular antibiotics. The surviving populations diversified, giving rise to stable strains with alternate colony morphologies, distinct proteomes, and altered metabolic properties. Further analysis in these studies showed that alterations in colony morphology were not solely observed during survival, but could also be induced in models mimicking acute infection. However, diversification in certain metabolic pathways occurred only during survival, and this metabolic diversification was observed at the transcriptional level. Further, one of three clinical isolates from patients with recurrent pharyngitis was altered in its metabolic profile, suggesting metabolic diversification may be occurring in vivo. The survivor strains had varied transcriptional changes in the genes encoding the virulence factors emm, slo, and speB. All of the stationary phase-derived survivor strains and two intracellular survival-derived strains had attenuated virulence in zebrafish. Most of the attenuated strains disseminated to the spleen and were cleared within three days. A whole blood killing assay showed a strong correlation between bacterial killing and emm expression. While the diversification appeared random, these strains retained their multilocus sequence type (MLST). These results suggest S. pyogenes strains with the same MLST, but diverse virulence properties, may arise during survival in the host.
Temple University--Theses
Steinberg, Gregory. "Long-term Stationary Phase Behavior of Streptococcus pyogenes Biofilms". Master's thesis, Temple University Libraries, 2012. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/170151.
Pełny tekst źródłaM.S.
Long-term Stationary Phase Behavior of Streptococcus pyogenes Biofilms Department of Microbiology and Immunology Streptococcus pyogenes is the etiological agent of many human diseases ranging from mild superficial skin infections and pharyngitis to life-threatening necrotizing fasciitis. There can be several complications as a result of S. pyogenes infection including post-streptococcal glomerulonephritis and rheumatic fever, which leads to rheumatic heart disease. Despite the significant virulence associated with the pathogen, the bacteria can also persist asymptomatically in human host carriers. S. pyogenes is characterized by significant strain-to-strain variation with many single nucleotide polymorphisms and differences in genetic content of up to 33% of the genome. Active infection is associated with the rapid growth of the pathogen, whereas survival or carriage is associated with slow growth. Our laboratory has demonstrated that during survival in long-term stationary phase cultures and in eukaryotic cells, S. pyogenes diversifies into a mixed population. Isolates from this population show diversification in their proteome, in metabolism, and in virulence factor transcription patterns. These are stable, heritable changes with unique mutations in global gene regulators in some isolates, suggesting that an accumulation of genetic mutations leads to diversification. There are two proposed modes of survival in the human host; by taking residence intracellularly in host cells and as biofilms. Previous studies showed that isolates surviving within eukaryotic cells acquire heritable changes in metabolism and virulence factor expression. Biofilms are highly organized structures formed by many bacteria, which provide resiliency to harsh environmental conditions. It has been demonstrated that S. pyogenes form biofilms in vivo and in vitro, and up to 90% of clinical isolates can form biofilms. Considering the resiliency of biofilms, and the organized roles played by individual cells in biofilms, we hypothesized that biofilms may provide S. pyogenes with a niche for persistence and diversification. Despite the capacity for survival of planktonic cells, we have found that viable cells could not be isolated from static biofilms after 10 days. No metabolic variants were found among biofilm isolates prior to loss of biofilm viability. Biofilm structure was examined using confocal microscopy to image cells after LiveDead® staining. These experiments revealed that the biofilms lost viability rapidly, and also appeared to disperse. Dispersion of 2-day old biofilms could be induced with culture supernatants collected from 7-day old planktonic cells. Overall, the results of these studies suggest that secreted factors from late stationary phase cultures induce biofilm dispersion and biofilms do not serve as a niche for long-term survival and diversification of S. pyogenes. Therefore, S. pyogenes biofilms may be more critical for initial colonization of the oropharynx. These studies may provide a valuable insight to the role of biofilms in S. pyogenes infections.
Temple University--Theses
Galeas, Trilce Michelle. "Thermoregulation of Capsule Production of Streptococcus pyogenes Strain HSC5". OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/122.
Pełny tekst źródłaWright, Jordan. "Capsule Thermoregulation and Non-Coding RNA in Streptococcus pyogenes". OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1505.
Pełny tekst źródłaJohansson, Söderberg Jenny. "The streptococcal IgG degrading enzyme IdeS : studies on host-pathogen interactions". Doctoral thesis, Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-53706.
Pełny tekst źródłaLibkind, Marianna. "SiaA, a heme protein". unrestricted, 2006. http://etd.gsu.edu/theses/available/etd-02192007-092252/.
Pełny tekst źródłaTitle from title screen. Under the direction of Dabney White Dixon. Electronic text (46 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Aug. 1, 2007. Includes bibliographical references (p 45-46).
Fontaine, Michael Christopher. "Allel-replacement mutagenesis of group A streptococci". Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285338.
Pełny tekst źródłaParks, Thomas Edward. "Host genetic susceptibility to group A streptococcal disease". Thesis, University of Cambridge, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.709471.
Pełny tekst źródłaAbe, Lucienne M. "Adhesion and internalization of group A streptococcus isolates found in Hawaii". Thesis, University of Hawaii at Manoa, 2003. http://proquest.umi.com/pqdweb?index=0&did=764803591&SrchMode=2&sid=1&Fmt=2&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1233167604&clientId=23440.
Pełny tekst źródłaVindebro, Reine. "Studies on secreted cysteine proteases of Streptococcus pyogenes : IdeS and SpeB". Doctoral thesis, Umeå universitet, Institutionen för molekylärbiologi (Medicinska fakulteten), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-88223.
Pełny tekst źródłaAlmengor, Audry C. "Transcriptional regulation of the MGA virulence regulon in Streptococcus pyogenes". Access to abstract only; dissertation is embargoed until after 12/19/2006, 2005. http://www4.utsouthwestern.edu/library/ETD/etdDetails.cfm?etdID=115.
Pełny tekst źródłaAnderton, Stephen M. "A study of murine T lymphocyte responses to Streptococcus pyogenes". Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287332.
Pełny tekst źródłaTurner, Claire Elizabeth. "SpyCEP : The Interleukin 8 Cleaving Streptococcus pyogenes Cell Envelope Proteinase". Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501216.
Pełny tekst źródłaAbou, El Enien Ibrahim. "Caractérisation des propriétés biologiques du facteur d'opacité de Streptococcus pyogenes". Lyon 1, 1991. http://www.theses.fr/1991LYO1T067.
Pełny tekst źródłaZarate, Bonilla Lina Johana. "Characterization of Chromosomally Encoded Toxin-Antitoxin Systems in Streptococcus pyogenes". Doctoral thesis, Humboldt-Universität zu Berlin, 2019. http://dx.doi.org/10.18452/20547.
Pełny tekst źródłaStreptococcus pyogenes is a human pathogen with a remarkable ability to colonize different tissues and to endure diverse host-induced stress conditions through mechanisms that have yet to be fully understood. One strategy employed by bacteria to cope with changing environments are toxin-antitoxin (TA) genetic modules. Under non-ideal conditions, the antitoxin is subject to proteolysis and thus the freed toxin protein can target crucial pathways in the cell modulating bacterial growth. This study, describes the characterization of two chromosomally encoded ParDE-like TA systems from the human pathogen S. pyogenes. The antitoxin-toxin genes of the parDEF1 and parDE2 TA systems are co-transcribed and triggered by stress-induced conditions. The parDE2 TA showed an inspected mRNA processing under amino acid starvation which suggest a putative post-transcriptional regulation. At the post-translational level, both systems are controlled by ClpXP antitoxin-protein degradation in vivo, an important factor for TA triggering. Furthermore, bacterial plasmid-based expression of the toxins ParE1 and ParE2 resulted in effects in cell viability while the antitoxin molecules ParD1 and ParD2 were able to prevent the toxins lethality, respectably. Unlike canonical antitoxins, both ParD1 and ParD2 molecules also displayed deleterious effects, which seemed to be exclusive and related with the N-terminus domain potentially involved in DNA-interaction. Finally, the ParE toxins presented remarkable plasticity, able to harm not only gyrase but also topoisomerase IV, two important bacterial drug targets that modulate DNA-topology. These results expand the view on the ParE molecular targets and highlight the diverse mechanisms TAs employ to modulate bacterial physiology. We also provide more insights into possible mechanisms that S. pyogenes employs to endure stress in the host and efficiently cause disease.
Tesorero, Melendez Rafael Angel. "Experimental validation for computationally predicted small RNAs of Streptococcus pyogenes". OpenSIUC, 2011. https://opensiuc.lib.siu.edu/theses/769.
Pełny tekst źródłaSwe, Pearl M., i n/a. "Mode of action of dysgalacticin and mechanism of its producer cell immunity". University of Otago. Department of Microbiology & Immunology, 2008. http://adt.otago.ac.nz./public/adt-NZDU20081119.111402.
Pełny tekst źródłaSylla, Maguette Dème. "Contribution à l'étude de l'action opsonisante des immunoglobulines sur les streptocoques du groupe A". Lyon 1, 1987. http://www.theses.fr/1987LYO1T126.
Pełny tekst źródłaRivera, Martínez M. Alba. "Estudi epidemiològic d'infeccions invasives i no invasives produïdes per Streptococcus pyogenes". Doctoral thesis, Universitat Autònoma de Barcelona, 2008. http://hdl.handle.net/10803/3920.
Pełny tekst źródłaS'ha realitzat un estudi retrospectiu de base hospitalària que inclou 126 soques de S. pyogenes (27 procedents d'infeccions invasives i 99 d'infeccions no invasives) aïllades entre gener de 1999 i juny de 2003. Les soques de S. pyogenes es van caracteritzar en base a la distribució de tipus i subtipus emm i els perfils genètics de superantígens (SAgs) (speA-C, speF-J, speL, speM, ssa i smeZ). Tanmateix, es va determinar la prevalença i els mecanismes de resistència a macròlids, tetraciclina i levofloxacino.
Les formes clíniques més freqüents d'infecció invasiva van ser les infeccions de la pell i teixits tous (40,7%). La SSTS es va registrar en quatre (14,8%) dels casos invasius i es va associar a FN en la meitat dels casos. La majoria dels pacients afectats de quadres invasius eren adults, en particular d'edat avançada i de mitjana edat, i una elevada proporció presentaven factors predisposants, destacant l'alteració de la barrera cutània, la infecció per HIV, l'ús de drogues per via parenteral, i les neoplàsies.
En la col·lecció de 126 soques analitzada es van identificar un total de 29 tipus emm amb una distribució encapçalada pel tipus emm1 (17,5%), seguit d'emm3 (8,7%), emm4 (8,7%), emm12 (7,1%), emm28 (7,1%), emm11 (6,3%) i emm77 (6,3%). Aquests set tipus van constituir el 61,9% del total de soques. No es van observar diferències significatives en la distribució de tipus emm entre soques aïllades d'infeccions invasives i no invasives amb l'única excepció del tipus poc freqüent emm25 que es va trobar associat a infeccions invasives en addictes a drogues per via parenteral. Es va trobar una forta correlació entre el patró de SAgs i el tipus emm independentment del tipus d'infecció.
La resistència a eritromicina va mostrar un increment anual progressiu del 16,6% (1999) al 38,8% (2003) i va estar causada per soques pertanyents a 11 tipus emm. Les soques mef(A) positives dels tipus emm4, emm12 i emm75 i erm(B) positives dels tipus emm11 i emm25 constituïren el 80% de les soques resistents. La freqüència de resistència a tetraciclina va fluctuar durant el període estudiat (màxim 34,6% el 2002 i mínim 15,8% el 2001) i va ser superior en les soques resistents a eritromicina que en les soques sensibles (42,8% vs 18,7%). En les soques resistents a tetraciclina el gen tet(M) va ser el predominant i es va trobar en soques pertanyents a 14 tipus emm, mentre que el gen tet(O) només es va trobar en soques emm77. No es van observar diferències significatives en la prevalença de resistència a eritromicina ni a tetraciclina en el grup invasiu respecte del no invasiu.
La prevalença de resistència a levofloxacino fou del 3,2%, incloent quatre soques amb sensibilitat reduïda o resistència intermèdia (CIM 2-4 µg/ml) i dues soques amb resistència d'alt nivell (CIM >32 µg/ml). La resistència de baix nivell es va associar a substitucions únicament en ParC (Ser80Pro, Ser79Ala, Ser79Phe i Ala121Val), mentre que la resistència d'alt nivell es va relacionar amb mutacions en ParC (Ser79Phe i Ala121Val) i GyrA (Ser81Tyr).
Streptococcus pyogenes (GAS) is a human pathogen responsible for a wide array of infections, ranging from pharyngitis and impetigo to severe invasive infections such as necrotizing fasciitis (NF) and streptococcal toxic shock syndrome (STSS). The resurgence and persistence of severe forms of GAS diseases reported since the mid 1980s have motivated intensive research on epidemiological, microbiological and clinical aspects of these diseases.
A retrospective hospital-based study was conducted including 126 GAS isolates (27 from invasive infections and 99 from non-invasive infections) collected from January 1999 to June 2003. GAS isolates were characterized by emm type and subtype and superantigen (SAg) gene profile (speA-C, speF-J, speL, speM, ssa and smeZ). The prevalence and mechanisms of macrolide, tetracycline and levofloxacin resistance were also determined.
The most common clinical presentations of invasive cases were skin and soft-tissue infections (40.7%). SSTS occurred in four cases (14.8%) and was associated to NF in half of the cases. Most invasive cases were found in adults, in particular among the elderly and the middle-aged, and a large proportion had underlying conditions, the most frequent being skin lesions, HIV infection, injection drug use, and malignancy.
A total of 29 emm types were identified among the 126 isolates; the most prevalent were emm1 (17.5 %), followed by emm3 (8.7 %), emm4 (8.7 %), emm12 (7.1 %), emm28 (7.1 %), emm11 (6.3 %) and emm77 (6.3 %). These seven emm types accounted for 61.9 % of isolates. There were no differences in the emm type distribution between invasive and non-invasive infections, except for emm25 isolates, which were associated with invasive infections in injecting drug users. The SAg gene profiles were closely associated with the emm type and were independent of the disease type.
The prevalence of erythromycin resistance showed an annual progressive increase from 16.6% (1999) to 38.8% (2003) and was caused by isolates belonging to 11 emm types. mef(A)-positive emm types 4, 12 and 75, and erm(B)-positive emm types 11 and 25 were responsible for up to 80% of the erythromycin-resistant isolates. The prevalence of tetracycline resistance fluctuated over the period studied (maximum 34.6% in 2002 and minimum 15.8% in 2001) and was higher in erythromycin-resistant isolates than in susceptible isolates (42.8% vs 18.7%). Among the tetracycline-resistant isolates, the tet(M) determinant was the most prevalent and was distributed in isolates belonging to 14 emm types, whereas tet(O) was only found in emm77 isolates. No significant differences in resistance rates to erythromycin or tetracycline were found between invasive and non-invasive isolates. The rate of resistance to levofloxacin was 3.2%, encompassing four isolates with reduced susceptibility or intermediate resistance (MIC 2-4 µg/ml) and two isolates with a high level of resistance (MIC >32 µg/ml). Low-level resistance was associated with alterations in ParC (Ser80Pro, Ser79Ala, Ser79Phe and Ala121Val), while high-level resistance was associated with alterations involving both ParC (Ser79Phe and Ala121Val) and GyrA (Ser81Tyr).
Whatmore, Adrian Mark. "Sequence analysis of the emm-like gene family of Streptococcus pyogenes". Thesis, University of Newcastle Upon Tyne, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357642.
Pełny tekst źródłaAlam, Faraz Mainul. "Modelling nasopharyngeal colonisation by Streptococcus pyogenes : bioluminescence and other longitudinal techniques". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14463.
Pełny tekst źródłaPower, Daniel Aaron, i n/a. "Non-culture based studies of the human upper respiratory tract microbiota and preliminary considerations of the influence of bacteriocin producing commensal and pathogenic oral streptococci". University of Otago. Department of Microbiology & Immunology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20070620.160726.
Pełny tekst źródłaAmicis, Karine Marafigo De. "Análise in vitro da capacidade de cobertura da vacina em desenvolvimento contra Streptococcus pyogenes". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5146/tde-02082013-144608/.
Pełny tekst źródłaStreptococcus pyogenes (Group A) is a Gram positive and beta-hemolytic bacteria, responsible for infections such as Pharyngitis, Sepsis, Necrotizing Fasciitis and Streptococcal Toxic Shock Syndrome. Susceptible individuals may develop post-streptococcal non-suppurative autoimmune sequelae such as Rheumatic Fever, Rheumatic Heart Disease and Acute Glomerulonephritis. The M protein is the major bacterial antigen. It consists of approximately 450 amino acid residues arranged in four regions (A, B, C and D), containing some repeated blocks. C and D regions are conserved and the N-terminus (regions A and B) is polymorphic. Currently there are over 250 known emm genotypes worldwide, according to the Centers for Disease Control and Prevention. Several years ago the development of a vaccine against S. pyogenes (StreptInCor - medical identification) was initiated, based on the M protein conserved region, aiming to protect against streptococcal infections without causing autoimmune reactions. In the present study we analyzed the \"in vitro\" ability of anti-StreptInCor antibodies to neutralize/opsonize the most frequent S. pyogenes strains in Sao Paulo by examining the strains recognition by sera from StreptInCor immunized mice. We also evaluated the presence of cross reactive antibodies directed to the human heart valve tissue by Western blotting. Anti-StreptInCor antibodies were able to neutralize/opsonize at least 5 strains, showing that the immunization with StreptInCor can be effective against several S. pyogenes strains as well as preventing infection and subsequent sequelae, without causing autoimmune reactions.
Noschang, Juliana. "Variabilidade genética de isolados de Streptococcus pyogenes por meio de marcadores RAPD". reponame:Repositório Institucional da UFPR, 2013. http://hdl.handle.net/1884/29830.
Pełny tekst źródła