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Dissertations / Theses on the topic 'Pili de type IVa'

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Published: 25 May 2024
Last updated: 31 July 2025

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1

Zatakia, Hardik M. "Characterization of symbiotically important processes in Sinorhizobium meliloti." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/56652.

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Bacteria perform biological nitrogen fixation (BNF) which leads to conversion of N2 to ammonia. One of the best studied models of BNF is the symbiotic association of Sinorhizobium meliloti - Medicago sativa (alfalfa). Since alfalfa is a major source of animal feed and the fourth largest crop grown in the USA, enhanced understanding of this symbiosis can have implications for increasing crop yields, reducing environmental contamination and food costs. Studies discussed here focus on two symbiotically important bacterial traits, type IVb pili and chemotaxis. Chapter 2 characterizes S. meliloti t
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2

Berry, Jamie. "Structural characterization of type IV pilus biogenesis proteins." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/structural-characterization-of-type-iv-pilus-biogenesis-proteins(1e0d7119-58d5-4e5d-839d-daef8deb76ab).html.

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Type IV pili, or fimbriae, are long, thin proteinaceous appendages found on the surface of many well-known pathogens. They mediate a variety of important virulence functions for the organism, such as twitching motility, biofilm formation, uptake of genetic material and host cell recognition and adhesion. Pili are formed by the rapid polymerization and de-polymerization of the pilin subunit, and this is orchestrated by a complex macromolecular machine which spans the bacterial cell envelope, requiring a variety of gene products. The type IV pilus biogenesis system is closely related to the bact
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3

Jacobsen, Theis. "Structure and assembly of bacterial type IV filaments unravelled by an integrative approach." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS146.

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La superfamille des filaments de type IV (TFF) est un groupe de machines moléculaires localisées dans la membrane des bactéries et des archées. Ces machines associent des polymères protéiques de manière non-covalente appelés des pili, qui s’étendent depuis la cellule pour réaliser plusieurs fonctions qui ont évolué spécifiquement pour s’adapter à des organismes hôtes différents. La superfamille TFF comprend le système de sécrétion de type II (T2SS) et les pili de type IVa (T4aP). Le T2SS induit la sécrétion de substrats chez les bactéries Gram-négatives. Ces substrats sont en général des enzym
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4

Luna-Rico, Areli-Noemi. "Enterobacterial type IV pili : structure, assembly and molecular function." Thesis, Sorbonne Paris Cité, 2018. https://theses.md.univ-paris-diderot.fr/LUNARICO_Areli_4_va_20180629.pdf.

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Nombreuses espèces bactériennes présentent des fibres à leur surface qui leur permettent d’interagir avec leur environnement. Les pili de type 4 (PT4) sont des fibres longues, fines et flexibles, impliquées dans des fonctions multiples telles que l'adhérence, la motilité, la sécrétion, l'import d'ADN et la formation des biofilms. Ils sont composés de milliers de copies de sous-unité majeure de piline et sont assemblés par un complexe protéique localisé dans l'enveloppe bactérienne. Dans cette étude, nous nous sommes intéressés aux PT4 chez Escherichia coli entérohémorragique (EHEC) de sérotype
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5

Seow, Vui Yin. "DNA Transformation and Type IV Pili in Neisseria gonorrhoeae." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS049.

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La résistance aux antibiotiques, évidente chez des souches telles que Neisseria gonorrhoeae, est une crise sanitaire mondiale. Il est vital de comprendre son mécanisme, en particulier la transformation naturelle par les Pili de type IV de ces bactéries. Bien qu'elle ait été découverte en 1928, la transformation naturelle n'a toujours pas été élucidée. La dépendance de Neisseria gonorrhoeae à l'égard des Pili de type IV en fait un modèle idéal pour l'étude de ce processus.Cette thèse se lance dans une exploration intensive des processus complexes de transformation de l'ADN au sein de Neisseria
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6

Alteri, Christopher. "Novel Pili of Mycobacterium tuberculosis." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1276%5F1%5Fm.pdf&type=application/pdf.

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7

Couchman, Edward. "Investigating the Type IV pili of Clostridium difficile and Clostridium sordellii." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/48055.

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Type IV pili (T4P) are the only type of bacterial pili known to be produced by both Gram-negative and Gram-positive organisms. Though the main pilus shaft consists primarily of only one protein (the major pilin), T4P are unusual in their complexity, requiring multiple (10 or more) different protein components for assembly. Like most types of pili, T4P often function as virulence factors. In particular, T4P frequently operate as adhesins, enabling bacteria on which they are present to stick to each other (to form a biofilm or suchlike) or to adhere directly to host cells. Many T4P systems are a
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8

Hendrick, William Anthony. "Molecular Analysis of Type IV Pilus Assembly in Clostridium perfringens." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81696.

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Clostridium perfringens is a Gram-positive anaerobe capable of causing disease in humans and many animals. C. perfringens is able to move across surfaces in a manner that is dependent on growth and type IV pili. Type IV pili are filaments that can be extended away from the cell by rapid polymerization, and retracted by depolymerization. Furthering the understanding of the initial and final energetic states of the pilins will reveal insights into possible mechanisms of type IV pilus assembly. Toward that end, a pilin was purified from the Gram-negative pathogen Pseudomonas aeruginosa and inco
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9

Amerighi, Fulvia. "Impact of S.pneumoniae type-I pilus and its subunits on bacterial adherence to human epithelial cells." Doctoral thesis, Università degli studi di Padova, 2013. http://hdl.handle.net/11577/3422591.

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S. pneumoniae is a human pathogen able to cause both invasive and non-invasive diseases as well as to colonize the nasopharyngeal tract of children and adults. Despite pneumococcus is a leading cause of morbidity and mortality worldwide, the pathogenic mechanisms exploited by S. pneumoniae are not yet clear. A critical step is colonization of the nasopharynx and the initial interaction of pneumococci with host cells. Recently, pili were discovered in gram-positive bacteria, mediating critical host-bacterial interactions, such as adherence to the epithelium, biofilm formation and translocation
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10

Hartman, Andrea H. "Use of an Inducible Promoter to Characterize Type IV Pili Homologues in Clostridium perfringens." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76874.

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Researchers of <i>Clostridium perfringens</i>, a Gram-positive anaerobic pathogen, were lacking a tightlyregulated, inducible promoter system in their genetic toolbox. We constructed a lactose-inducible plasmid-based system utilizing the transcriptional regulator, BgaR. Using the <i>E. coli</i> reporter GusA, we characterized its induction in three different strains of <i>C. perfringens</i>. We then used a newly-developed mutation system to create in-frame deletion mutants in three genes with homology to Type IV pilins, and we used the promoter system described above to complement the mutants.
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11

Paranjpye, Rohinee. "The role of a Vibrio vulnificus type IV pilin in pathogenesis and in persistence in oysters /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5372.

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12

Gault, Joseph. "Development of Top-Down Mass Spectrometry Approaches for the Analysis of Type IV Pili." Palaiseau, Ecole polytechnique, 2013. https://tel.archives-ouvertes.fr/pastel-00987029/document.

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La caractérisation de protéines par spectrométrie de masse "top-down" (TDMS) possède plusieurs avantages sur l'approche "bottom-up" (BU), notamment pour la caractérisation des protéoformes; c'est-à-dire l'ensemble des protéines exprimées par la cellule, y compris celles portant les modifications post-traductionnelles (MPT). Dans cette thèse la TDMS a été développée pour l'analyse des pili de type IV (T4P) à la fois sur Orbitrap et sur FT-ICR. Les T4P sont des organelles extracellulaires composées principalement d'une protéine, la piline majeure, qui peut être fortement décorée par des MPT. Pou
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13

Lee, Ka Man. "Regulation of expression of the type IV B pili-encoding operon of salmonella typhi /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BICH%202003%20LEE.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.<br>Includes bibliographical references (leaves 110-127). Also available in electronic version. Access restricted to campus users.
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14

Kennouche, Paul. "New insights into meningococcal pathogenesis : exploring the role of the major pilin PilE in the functions of type IV pili Mechanisms of meningococcal type IV pili multiple functions revealed by deep mutational scanning." Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=1972&f=12515.

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Les pili de type IV (PT4) sont des filaments micrométriques qui exercent de multiples fonctions à la surface de nombreux procaryotes. Chez Neisseria meningitidis, les PT4 sont des homopolymères de la piline majeure PilE. Leur implication dans l'agrégation interbactérienne et l'adhésion aux cellules humaines les rend centraux dans la virulence du méningocoque. Cependant, les mécanismes permettant aux PT4 d'exercer ces diverses fonctions restent trop élusifs. Durant ce doctorat, nous avons simultanément déterminé les régions de PilE impliquées dans l'assemblage des pili, l'auto-agrégation, l'adh
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15

Imhaus, Anne-Flore. "Rôle et mode d’action des pilines mineures des pili de type IV de Neisseria meningitidis." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T019/document.

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Les pili de type IV (PT4), certainement les organelles les plus répandues des bactéries à Gram-négatif, sont des machineries à multiples fonctions qui jouent un rôle crucial dans la pathogenèse de nombreux pathogènes humains, notamment notre modèle Neisseria meningitidis. L’assemblage des PT4 nécessite une machinerie complexe incluant au moins vingt protéines localisées dans la membrane interne, le périplasme et la membrane externe. Certaines de ces protéines ne sont pas nécessaires pour la biosynthèse des PT4, mais supportent les fonctions qui leur sont associées. Ces protéines, appelées pili
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16

Salomonsson, Emelie. "The role of the Type IV pili system in the virulence of Francisella tularensis." Doctoral thesis, Umeå universitet, Molekylärbiologi (Teknisk-naturvetenskaplig fakultet), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1656.

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Francisella tularensis is a Gram-negative intracellular pathogen causing the zoonotic disease tularemia. F. tularensis can be found almost all over the world and has been recovered from several animal species, even though the natural reservoir of the bacterium and parts of its life cycle are still unknown. Humans usually get infected after handling infected animals or from bites of blood-feeding arthropod vectors. There are four subspecies of F. tularensis: the highly virulent tularensis (Type A) that causes a very aggressive form of the disease, with mortality as high as 60% if untreated, the
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17

Brown, Daniel Robert. "Systematic analysis in Neisseria meningitidis of proteins that fine-tune functions mediated by type IV pili." Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6834.

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Type IV pili (Tfp) are widespread virulence factors whose multifunctional ability sets them apart from other pili. Tfp mediate adhesion as well as aggregation, competence for DNA transformation and twitching motility (a non-­flagellar form of locomotion) in many bacterial pathogens. The molecular mechanisms of these functions and the biogenesis of these pili are not yet fully understood. To better understand Tfp biology, our group started a systematic characterization of all of the proteins involved in Tfp biology in a well-­defined genetic background, Neisseria meningitidis strain 8013. Scree
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18

Murray, Samantha Rose. "Characterization of Type IV Pilus System Genes and Their Regulation in Clostridium perfringens." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/86173.

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Clostridium perfringens is a Gram-positive (Gr+) anaerobic pathogen that was found to contain Type IV pilus (T4P) system genes within the genomes of all its sequenced strains. T4P are widely used in Gram-negative organisms for aggregation, biofilm formation, adherence, and DNA uptake. Because few examples of T4P-utilizing Gram-positive bacteria are studied to date, we wanted to characterize the T4P system in this Gr+ bacterium. To understand the regulation of T4P genes and therefore better understand their expression, we employed the highly powerful next-generation sequencing tool RNA-seq i
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19

Nikraftar, Sarah. "Localization of Type IV Pilin Polymerization Proteins in Clostridium perfringens." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/71742.

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Clostridium perfringens is a spore-forming anaerobic Gram-positive rod which has gliding motility through type IV Pili (TFP). Since the discovery of TFP in Gram-positive bacteria is relatively new, more studies are required to understand the mechanism and interaction of the proteins of this machinery. Moreover, the similarities between TFP and type 2 secretion system (T2SS) suggest that C. perfringens has also a T2SS. We studied the localization of TFP ATPases, PilB1, PilB2 and PilT in Bacillus subtilis to compare the localization in an organism other than C. perfringens and which lacks any
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20

Friedrich, Carmen [Verfasser], and Lotte [Akademischer Betreuer] Sogaard-Andersen. "Deciphering the assembly pathway of type IV pili in Myxococcus xanthus / Carmen Friedrich. Betreuer: Lotte Sogaard-Andersen." Marburg : Philipps-Universität Marburg, 2013. http://d-nb.info/1045729701/34.

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21

Rakotoarivonina, Harivony. "Le système d'adhésion de ruminococcus albus : implication de pili de type IV et de deux glycosl-hydrolases." Lyon 1, 2003. http://www.theses.fr/2003LYO10211.

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Ruminococcus albus est une des bactéries cellulolytiques majeures du rumen. L'adhésion de cette bactérie à la cellulose est une première étape indispensable dans le processus de dégradation des fibres végétales. L'objectif de ce travail est d'élucider les mécanismes impliqués dans l'adhésion de R. Albus à la cellulose. Ce travail a permis de caractériser une glycoprotéine de 25 kDa (GP25) sous-produite par un mutant non adhérent de la souche 20 de R. Albus. GP25 est la sous-unité majeure des pili de type IV observés à la surface de R. Albus 20. Ces pili sont nécessaires à l'adhésion de la bact
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22

PUJOL, CELINE. "Les pili de type iv chez neisseria meningitidis, elements cles des echanges d'information entre bacteries et cellules eucaryotes." Paris 6, 1999. http://www.theses.fr/1999PA066417.

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Neisseria meningitidis est un pathogene extracellulaire exclusivement humain responsable de septicemies et de meningites. Ce tropisme meninge est specifique de l'infection meningococcique. Les pili de type iv, appendices filamenteux repartis a la surface des bacteries, jouent un role central dans cette interaction. En l'absence de pili, le meningocoque est incapable d'adherer aux cellules de l'hote et de franchir la barriere hemato-encephalique. Dans le but de preciser les mecanismes en cause, nous avons etudie l'interaction du meningocoque avec une monocouche de cellules epitheliales humaines
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23

Lövkvist, Lena. "Receptor Interactions Between Pathogenic Bacteria and Host Cells." Doctoral thesis, Uppsala University, Department of Medical Biochemistry and Microbiology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7782.

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<p>This thesis focuses on host and pathogen specific interactions during invasive disease. We have investigated the role and impact of different virulence factors of <i>Neisseria gonorrhoeae, N. meningitidis</i> and <i>Streptococcus pyogenes</i> on host epithelial cells and <i>in vivo</i>. </p><p><i>N. gonorrhoeae</i> cause the sexually transmitted disease gonorrhoea and <i>N. meningitidis</i> is the most common cause of bacterial meningitis and may be leathal to the host within hours of infection. The neisserial type IV pili were shown to have an important impact on host cells for the induct
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24

Harding, Christian Michael. "Discovery and demonstration of functional type IV pili production and post-translational modification by a medically relevant Acinetobacter species." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1428405412.

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25

Mouville, Clémence. "Interaction entre les pili de type IV et le phage filamenteux MDA : impact potentiel sur la virulence de Neisseria meningitidis." Electronic Thesis or Diss., Université Paris Cité, 2024. http://www.theses.fr/2024UNIP5235.

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Neisseria meningitidis (Nm) est une bactérie commensale du nasopharynx humain qui traverse quelques fois la barrière nasopharyngée et se propage dans la circulation sanguine jusqu'à atteindre les méninges. Un bactériophage filamenteux appelé MDA (Meningococcal Disease Associated) est associé aux infections invasives à méningocoques chez les jeunes adultes. Le MDA semble augmenter l'incidence de la maladie en augmentant la colonisation bactérienne au point d'entrée. L'objectif de ce travail a été de comprendre le mécanisme moléculaire précis de l'infection de Nm par le MDA. L'étude des mutants
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26

Santos, Moreno Javier. "Molecular mechanism of pseudopilus assembly in the Klebsiella oxytoca type II secretion system." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC216/document.

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Le système de sécrétion de type II (SST2) permet la sécrétion de protéines repliées à travers la membrane externe chez les bactéries à Gram-négatif. Le SST2 est une nano-machine enchâssée dans l’enveloppe bactérienne, proche par sa composition et structure aux systèmes d’assemblage des pili de type IV (PT4) impliqués, entre autres, dans d’adhésion et motilité. Chez Klebsiella oxytoca, la surexpression des gènes pul codant le SST2 permet l’assemblage de pili composées des sous-unités PulG. Ceci suggère qu’en conditions physiologiques l’assemblage d’un pseudopilus périplasmique permet la sécréti
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27

Bordeleau, Éric. "Régulation du c-di-GMP et rôle de ce messager secondaire dans la formation de pili de type IV chez Clostridium difficile." Thèse, Université de Sherbrooke, 2014. http://hdl.handle.net/11143/5385.

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Malgré la découverte du c-di-GMP en 1987, ce n’est que durant la dernière décennie que l’importance de ce messager secondaire dans la régulation des phénotypes bactériens a été exposée. Synthétisé par des diguanylate cyclases (DGC) et dégradé par des phosphodiestérases spécifiques (PDE), le c-di-GMP est prédit pour être un messager secondaire très répandu chez les bactéries et pratiquement exclusif à celles-ci. Le c-di-GMP est particulièrement reconnu pour son rôle dans la transition des bactéries motiles et planctoniques vers la formation de biofilm chez les bactéries à Gram négatif telles qu
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28

Potapova, Anna [Verfasser], and Lotte [Akademischer Betreuer] Soegaard-Andersen. "Regulation of type IV pili formation and function by the small GTPase MglA in Myxococcus xanthus / Anna Potapova ; Betreuer: Lotte Soegaard-Andersen." Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1214368220/34.

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29

Soyer, Magali. "Mécanismes moléculaires de la colonisation de l’endothélium par Neisseria meningitidis." Thesis, Paris 5, 2012. http://www.theses.fr/2012PA05T080.

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Les infections bactériennes touchant la circulation sanguine conduisent à un vaste éventail de graves pathologies, comme les chocs septiques ou les infections locales (endocardites et méningites). Neisseria meningitidis colonise avec succès l’endothélium vasculaire et cause des sepsis sévères. Ces infections résultent de la colonisation des cellules endothéliales de l’hôte, étape clef de la pathophysiologie à laquelle les travaux présentés dans ce manuscrit se sont intéressés. La colonisation de l’endothélium par N. meningitidis est un processus complexe qui implique l’adhésion et la multiplic
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30

Basso, Pauline. "Exolysine, un facteur de virulence majeur de Pseudomonas aeruginosa." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAV063/document.

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Pseudomonas aeruginosa est un pathogène opportuniste responsable d’infections nosocomiales sévères associées à un taux élevé de mortalité. Le système de sécrétion de Type III (SST3) et les effecteurs qu’il injecte sont considérés comme des facteurs de virulence prépondérants de P. aeruginosa. Récemment nous avons caractérisé, un groupe de souches ne possédant pas les gènes du SST3, mais dont la virulence repose sur la sécrétion d’une nouvelle toxine de 172 kDa, nommée Exolysine (ExlA) qui provoque la perméabilisation de la membrane des cellules hôtes. ExlA est sécrétée dans le milieu par une p
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31

Cheung, Fei Wai. "The effect of bile salts on expression from the pil and rci promoters associated with the type IVB pilus-encoding operon of salmonella enterica serovar typhi /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BICH%202003%20CHEUNG.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.<br>Includes bibliographical references (leaves 98-116). Also available in electronic version. Access restricted to campus users.
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32

Forslund, Anna-Lena. "Identification of new virulence factors in Francisella tularensis." Doctoral thesis, Umeå universitet, Molekylärbiologi (Teknat- och Medfak), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30857.

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Francisella tularensis, the causative agent of tularemia, is a highly virulent bacterium with an infection dose of less than ten bacteria. The ability of a pathogen to cause infection relies on different virulence mechanisms, but in Francisella tularensis relatively few virulence factors are known. Two F. tularensis subspecies are virulent in humans; the highly virulent subspecies tularensis, also referred to as type A, and the less virulent subspecies holarctica, also called type B. The aim of this thesis has been to improve the knowledge regarding the ability of Francisella to cause disease,
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33

Williams, Danielle A. "The AlgZ/R Two-Component System Is Responsible for Attenuation of Virulence in Pseudomonas aeruginosa." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3340.

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Pseudomonas aeruginosa is an important opportunistic pathogen. Many P. aeruginosa virulence factors are regulated by the AlgZ/R two component system. AlgZ is the sensor histidine kinase which phosphorylates AlgR, the response regulator. AlgR activates transcription of different gene targets based upon its phosphorylation state. The genes that encode AlgZ and AlgR are transcribed in an operon. While regulation of algR expression has been well studied, regulation of algZ expression has not. Using a pilW mutant in concert with algZTF-lacZ transcriptional fusion, we conducted a transposon mutagene
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34

Theophilou, Elena Stella. "Development of a novel genetic system for generation of markerless deletions in Clostridium difficile." Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/9616.

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C. difficile is an obligate anaerobic, Gram-positive, rodshaped and spore-forming bacterium. It is a well-recognised causative agent of antibiotic-associated diarrhoea and pseudomembranous colitis. C. difficile has emerged as an important nosocomial pathogen in recent years, associated with considerable morbidity, mortality and economic burden. Despite its importance, functional genomic studies have been lagging behind in comparison to other enteric pathogens. This is attributed to the fact that C. difficile is difficult to manipulate genetically and the lack of robust, reproducible mutagenesi
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35

Varga, John Joseph. "The Role of CcpA in Regulating the Carbon-Starvation Response of Clostridium perfringens." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/29759.

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Clostridium perfringens is a significant human pathogen, causing 250,000 cases of food poisoning in addition to several thousand potentially lethal cases of gas gangrene each year in the United States. Historically, work in this field has centered around toxin production, as C. perfringens can produce over 13 toxins. This work expands the knowledge of the starvation-response of C. perfringens, which includes several potential virulence factors, sporulation, motility and biofilm formation. Sporulation protects cells from a variety of stresses, including starvation. Efficient sporulation req
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36

Mikaty, Guillain. "Rôle des Pili de type IV dans le réarrangement de la surface cellulaire eucaryote induite par Neisseria meningitidis et conséquences sur la colonisation des barrières cellulaires." Paris 5, 2009. https://hal.archives-ouvertes.fr/tel-01262387.

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Neisseria meningitîdis est une bactérie à Gram négatif, à la fois commensale et pathogène de l'espèce humaine. Au cours de ces travaux, nous nous sommes intéressés à l'interaction entre cette bactérie et son hôte. La colonisation des cellules par N, meningitîdis est un processus complexe qui intègre : l'adhésion aux cellules de l'hôte dépendante de la présence de Pili de type IV (Pt4), la multiplication et la survie des bactéries, la formation de microcolonies et leur maintien sur les cellules puis l'envahissement progressif de la surface cellulaire. Cette étape de colonisation est centrale da
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Arantxa, Camus Etchecopar. "Mécanismes moléculaires impliqués dans la formation de biofilm à l’interface eau-composés organiques hydrophobes." Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3032/document.

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Les composés organiques hydrophobes (HOC), une grande famille de molécules naturelles ou d’origine anthropique incluant les lipides et les hydrocarbures, constituent une part significative de la matière organique dans les écosystèmes marins. Du fait de leur faible solubilité dans l’eau, les bactéries qui les dégradent requièrent la mise en place de fonctions cellulaires spécifiques permettant d’augmenter la fraction assimilable de ces HOC. La formation de biofilms à l’interface eau-HOC est une de ces stratégies adaptatives. C’est le cas pour Marinobacter hydrocarbonoclasticus SP17, modèle d’ét
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Black, Wesley P. "Regulation of Exopolysaccharide Production in Myxococcus Xanthus." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/30250.

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The surface gliding motility of Myxococcus xanthus is required for a multicellular developmental process initiated by unfavorable growth conditions. One form of the M. xanthus surface motility, social (S) gliding, is mediated by the extension and retraction of polarly localized type IV pili (Tfp). Besides Tfp, exopolysaccharides (EPS), another cell surface associated component, are also required for M. xanthus S motility. Previous studies demonstrated that the Dif chemotaxis-like signal transduction pathway is central to the regulation of EPS production in M. xanthus. Specifically, difA, difC
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Dienst, Dennis. "Untersuchungen zu Funktion und Struktur des Regulatorproteins Hfq in Synechocystis sp. PCC 6803." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2011. http://dx.doi.org/10.18452/16250.

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Das phylogenetisch weit verbreitete RNA-bindende Protein Hfq ist an einer Vielzahl von Prozessen innerhalb des bakteriellen RNA-Metabolismus, insbesondere im Rahmen der post-transkriptionellen Genregulation durch kleine RNAs (sRNAs) beteiligt. Hfq-Proteine zählen zu der Familie der Sm- und Lsm-Proteine und zeichnen sich strukturell durch die funktionelle Ausbildung ringförmiger Homohexamere aus. Cyanobakterielle Orthologe zeigen gegenüber den gut untersuchten Hfq-Proteinen aus E. coli und anderen Proteobakterien eine schwache Sequenzkonservierung und bieten auch daher einen interessanten Ansat
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Sundin, Charlotta. "Type III Secretion Mediated Translocation of Effector Exoenzymes by Pseudomonas aeruginosa." Doctoral thesis, Umeå : Univ, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-174.

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Virion, Zoé. "Interaction de Neisseria meningitidis avec les cellules endothéliales humaines : rôle des glycosylations des récepteurs cellulaires eucaryotes Receptor recognition by meningococcal type IV pili relies on a specific triantennary N-­glycan Sialic acid‐mediated allosteric activation of β2-­adrenoceptors An ADAM-­10 dependent EPCR shedding links meningococcal interaction with endothelial cells to purpura fulminans". Thesis, Sorbonne Paris Cité, 2018. https://wo.app.u-paris.fr/cgi-bin/WebObjects/TheseWeb.woa/wa/show?t=2296&f=12491.

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Neisseria meningitidis est une bactérie commensale du rhinopharynx portée de façon asymptomatique par 10 à 35% de la population. Pour une raison encore inconnue à ce jour, cette bactérie est capable de traverser la barrière épithéliale et ainsi proliférer dans la circulation sanguine de l’hôte, où elle est capable d’adhérer aux cellules endothéliales grâce aux pili de type IV. Sur ces cellules, le méningocoque interagit spécifiquement avec le récepteur d’adhésion CD147 et le récepteur β2-adrénergique qui active la signalisation sous la colonie bactérienne adhérente, favorisant l’ancrage de cel
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Ke-YingHsieh and 謝可盈. "The Contribution of Type IV Pili in Clostridium difficile pathogenesis." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7w95kp.

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Chiang, Yi Chien, and 江宜蒨. "Characterization of the Type IV pili gene cluster Streptococcus sanguinis SK36." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/88998232805241370382.

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碩士<br>長庚大學<br>生物醫學研究所<br>99<br>Streptococcus sanguinis is a primary colonizer of human tooth and an opportunistic pathogen for subacute endocarditis. A Type IV pili (Tfp) gene cluster was reported in the complete genome of Streptococcus sanguinis SK36 recently. The goal of this research aimed to analyze the expression and function of this gene cluster. The Tfp gene cluster is composed of total 16 genes, from pilB to pilD. A contiguous transcript was detected between pilD and the downstream lytB by RT-PCR, suggesting that lytB is also part of the operon. Three transcription initiation site
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Barnett, Timothy Carew. "A genetic and functional analysis of type IV pili produced by Aeromonas bacteria." Thesis, 1999. https://eprints.utas.edu.au/19091/1/whole_BarnettTimothyCarew1999_thesis.pdf.

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Bacteria belonging to the genus Aeromonas are ubiquitous water-borne organisms that are also present in many foods. Some strains are human gastrointestinal pathogens. However, the disease-causing mechanisms of these bacteria are not well understood. This is particularly true for intestinal colonisation, which is a critical step in the disease process. When this thesis commenced, there was evidence that filamentous surface structures (type IV pili) purified from diarrhoea-associated species had an important role in colonisation. These pili were designated "bundle-forming pili" (Bfp) becau
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Bulyha, Iryna [Verfasser]. "Regulation of the type IV pili localization in Myxococcus xanthus / vorgelegt von Iryna Bulyha." 2010. http://d-nb.info/1004808496/34.

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Tseng, Tzu Ying, and 曾姿穎. "Characterization and functional analysis of the type IV pili gene cluster in Streptococcus sanguinis SK36." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/33875483902144865967.

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碩士<br>長庚大學<br>生物醫學研究所<br>101<br>Streptococcus sanguinis is a member of the dental plaque and occasionally causes infective endocarditis. Thus far the gene cluster (pil) encoding type IV pili (Tfp) was found only in the genome of Streptococcus sanguinis SK36. Previous studies by using 5’ RACE analysis revealed 3 putative transcription initiation sites 5’ to the pil cluster. Short hair-like structures were observed on the surface of SK36 by using anti-SSA_2315 (PilA) antiserum under transmission electron microscopy. However, the biological functions of the Tfp in S. sanguinis SK36 remains un
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Wu, Hui Yu, and 吳蕙妤. "Regulation and functional analysis of the type IV pili gene cluster in Streptococcus sanguinis SK36." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/m9564z.

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Chiang, Poney Che. "Molecular investigation of the role of type 4 pili ATPases involved in twitching motility of Pseudomonas aeruginosa." 2005. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=371008&T=F.

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Wu, Chia Hua, and 吳佳樺. "Functional analysis of the type IV pili gene cluster in the twitching and non-twitching Streptococcus sanguinis strains." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/p57s9h.

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碩士<br>長庚大學<br>生物醫學研究所<br>106<br>A type IV pili (Tfp) gene pil cluster of 16 or 17 genes is found in strains of Streptococcus sanguinis but not in other oral streptococci. Although this cluster is highly conserved among S. sanguinis strains, only a few Tfp-expressing strains exhibit twitching motility. To understand the basis for twitching activity, this study examined the pil cluster and the twitching activity of 40 clinical S. sanguinis isolates. Among all isolates, pil-specific PCR products were observed in 39 isolates, indicating that the pil cluster is present commonly in clinical isola
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Tammam, Stephanie. "Characterization of PilP from the Type IV Pilus System of Pseudomonas aeruginosa." Thesis, 2012. http://hdl.handle.net/1807/43398.

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Pathogenic bacteria employ a number of mechanisms to induce infection and survive in host tissues, including toxin secretion and the formation of protective multicellular structures called biofilms. Type IV Pili (T4P) are highly conserved organelles essential for both the establishment of infection and biofilm maturation. The goal of this research is to gain a molecular level understanding of the function of the highly dynamic T4P of Pseudomonas aeruginosa. The pilMNOPQ operon encodes 5 members of a transmembrane complex that facilitates pilus function. While PilQ is the putative outer membran
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