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1
Weissgerber, Patrick. "Phagozytose-assoziierte Rezeptoren bei der Legionellen-Pathogenese." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967972728.
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Löwe, Stefan Bernhard [Verfasser]. "Risikofaktoren in Trinkwasser-Installationen für das Vorkommen von Legionellen / Stefan Bernhard Löwe." Bonn : Universitäts- und Landesbibliothek Bonn, 2019. http://d-nb.info/1200098293/34.
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Löwe, Stefan [Verfasser]. "Risikofaktoren in Trinkwasser-Installationen für das Vorkommen von Legionellen / Stefan Bernhard Löwe." Bonn : Universitäts- und Landesbibliothek Bonn, 2019. http://d-nb.info/1200098293/34.
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Igel, Liane. "Funktionale und molekulare Charakterisierung des Pad-Proteins von Legionella pneumophila." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1182434964636-36374.
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In der vorliegenden Arbeit wurde das Pad-Protein von Legionella pneumophila mit zell- bzw. molekularbiologischen sowie immunochemischen Methoden charakterisiert. Mittels Einbau des mutierten Pad-Locus, kodiert auf dem Plasmid pCS-25, in das Genom der L. pneumophila Stämme WH88 (Serogruppen 6) bzw. WH89 (Serogruppe 10) wurden je drei Pad-negative Mutanten gewonnen. Mit Hilfe der PCR, des Southernblot bzw. ELISA wurde der korrekte Austausch der Wildtypsequenz gegen den mutierten Bereich des Proteins nachgewiesen. Die Infektionsversuche mit den Mutanten bestätigten die Vermutung, dass das Protein eine Rolle an der initialen Kontaktaufnahme von L. pneumophila in den natürlichen Wirt, A. castellanii, hat. Dabei wurden signifikant niedrigere Aufnahmeraten der Mutanten im Vergleich zu den beiden Wildtypen beobachtet. Durch Kultivierung und Infektion des Ursprungstammes L. pneumophila Corby, der pad-negativen Mutante CP7 und der Pad-komplementierten Mutante bei 25°C, 30°C bzw. 37°C wurde der Einfluss der Temperatur auf die Funktion des Proteins untersucht. Die Ergebnisse zeigten dabei einen signifikanten Anstieg der Aufnahmeraten bei Vergleich von 25°C und 30°C bzw. 25°C und 37°C. Keine Signifikanz trat zwischen 30°C und 37°C auf. Ein zweiter Aspekt dieses Versuchs war die Prüfung der Infektionsrate in Abhängigkeit von der Proteinexpression unter dem Einfluss der Wachstumsphase. Dabei wurden durch vergleichende Infektion von A. castellanii mit exponentiellen (EP) bzw. stationäre Phase-Kulturen (SP) in diesem Versuch signifikante Unterschiede zwischen dem Wildtyp Corby und der Mutante CP7 bzw. zwischen der Mutante CP7 und der Pad+-Komplementante bei den jeweils untersuchten Temperaturen beobachtet. Keine signifikanten Unterschiede waren zwischen Wildtyp und Pad-Komplementante feststellbar. Zur Speziesübergreifenden Charakterisierung des Proteins Pad wurde das Wildtyplocus-kodierende Plasmid (pCS31) in die fünf non-pneumophila Stämme L. parisiensis (H962); L. bozemanii (L99-343); L. bozemanii (Frankreich5); L. longbeachae (A46) und L. tauriniensis (Koper11) durch Elektroporation übertragen. Im anschließenden ELISA wurde die Expression des Proteins Pad in den komplementierten Transformanten nachgewiesen. Die Infektionsversuche ergaben überwiegend signifikant höhere Aufnahmeraten der Pad-komplementierten Klone im Vergleich zu den Pad-negativen Wildtypen. Die Infektionsversuche zeigen, dass Pad nicht an der intrazellulären Replikation beteiligt ist. Die Ergebnisse der Infektionsversuche wurden parallel dazu durch mikroskopische Untersuchung intrazellulärer Bakterien bestätigt. Die Vermutung, dass die Expression von Pad als infektionsbeteiligtes Protein beim Übergang in die virulente Phase induziert wird, wurde durch die Kultivierung über 6 Tage bis in die späte stationäre Phase bestätigt. Die Kulturen des L. pneumophila Stammes JR32 zeigen im ELISA mit dem Pad-spezifischen Antikörper 61-1 ab der spätexponentiellen Phase (nach 24 Stunden) eine ansteigende Extinktion. Im Gegensatz dazu wurde für die GacA (LetA)-negative Mutante JR32gac- eine gleichbleibend hohe Expression des Proteins Pad über den gesamten Versuchszeitraum gemessen, was erste Hinweise liefert, dass Pad gacA bzw. letA-reguliert ist. Ein zellschädigender Einfluss der Bakterien auf die Atmungskette der Amöbenzelle zu frühen Zeitpunkten der Infektion (5, 30, 120 min) wurde mittels des Cell Titer Blue Cell Viability Assays festgestellt. Die Infektion mit hitzeabgetöteten Legionellen ergab dabei eine Toxizität unter 10 % bei allen drei untersuchten Zeitpunkten. Nach Infektion mit EP- als auch mit SP-Kulturen des Wildtyps Corby wurde eine maximale Toxizität zwischen 30 % und 40 % (120 min) gemessen. Bei der Mutante wurde eine Toxizität von ca. 28% der SP-Kultur nach 120 min Infektion beobachtet. Für die weiterführende Charakterisierung des Pad-Proteins wurde eine Maus mit dem rekombinanten Protein immunisiert. Dabei wurden zusätzlich zum vorhandenen Antikörper 61-1 die Antikörper 83-1 und 83-2 gewonnen. Bei diesen handelt es sich um IgG-Antikörper. Die durchgeführten Tests lassen vermuten, dass es sich um, in der Reaktion von Mak 61-1, ähnliche Antikörper handelt. Zur strukturellen Analyse des Pad-Proteins wurde mit zwei unterschiedlichen Phagenbibliotheken nach möglichen Epitopen für den Pad-spezifischen Antikörper 61-1 gesucht. Dabei wurde unabhängig voneinander mit beiden Phagen-Bibliotheken ein Epitop (L2) im C-terminalen Bereich ermittelt. Das Einfügen von Zufallsmutationen ließ keine Eingrenzung des Epitops zu. Da es jedoch dem, mit Mak 61-7 im Peptidspotting von C. Steudel (2001) ermittelten, Epitop C3 entspricht, ist davon auszugehen, dass es sich tatsächlich um das zweite putative Epitop für den Antikörper handelt. Des Weiteren wurde mit beiden Phagen-Bibliotheken das Epitop (L1) lokalisiert. Eine Eingrenzung dieses Epitops mittels Einfügen von Zufallsmutanten war nicht möglich. Durch site-spezifische Mutation wurden alle Aminosäuren des Epitops C1 (STEUDEL, 2001) in der putativen Signalsequenz ausgetauscht. Bei Testung der Mutanten auf ihre Bindungsfähigkeit an den Antikörper 61-1 im ELISA konnte eine Beteiligung der Aminosäuren Leucin11, Phenylalanin15, Glycin18 und Prolin20 beobachtet werden. Die Ergebnisse bestätigen, dass Pad an frühen Phasen der Infektion von A.castellanii durch L.pneumophila beteiligt ist. Es ist zu vermuten, dass dieses Pad-Protein einen Selektionsvorteil für den am häufigsten nachweisbaren Vertreter dieser Familie darstellt.
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Dilger, Thorsten [Verfasser], and André [Akademischer Betreuer] Gessner. "Untersuchungen zu Legionellen-Kontaminationen in Warmwassersystemen in Süddeutschland / Thorsten Dilger ; Betreuer: André Gessner." Regensburg : Universitätsbibliothek Regensburg, 2018. http://d-nb.info/1173974776/34.
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Petzold, Markus. "Array hybridization and whole genome sequencing as new typing tools for Legionella pneumophila." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233546.
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To understand transmissible human diseases, disciplines such as epidemiology and the surveillance of affected cases are as essential as the knowledge about the pathogenesis and the course of a disease. Epidemiologists categorize and estimate factors for public health risks by taking metadata into account including geographic aspects, health and social states to study a disease transmission and prevent further cases. In addition, a focus on the causative agents itself is necessary in order to understand their ecology and hence their virulence traits. The causative agents for a severe pneumonia named Legionnaires’ disease (LD) are bacteria of the genus Legionella. The putative sources of LD infection are any aerosol-generating natural or man-made fresh water systems. Due to this ubiquitous distribution of legionellae, it is difficult to find the source of infection. Therefore, it is necessary to isolate the bacterium from the suffering patients to further characterize it in the laboratory and to compare the clinical isolates with isolates obtained from probable environmental sources.
The predominant species isolated from LD patients is Legionella pneumophila serogroup (Sg) 1. Intensive genotyping of L. pneumophila Sg1 isolates by using the current gold standard method, the sequence-based typing scheme (SBT), revealed limitations in the discrimination of several sequence types (ST) which could not be compensated for by additional phenotypic typing scheme. In practical terms, this means that several clones or STs are disproportional frequently found in both, patients and water systems, and cannot be distinguished by current methods. Therefore, a distorted picture of endemic and globally-spread clones is generated and current typing methods cannot add substantial information during the identification of the infectious source. The aim of this thesis is to develop and implement new typing methods for L. pneumophila isolates with a higher resolution than the gold standard methods.
A DNA-DNA hybridization based microarray was designed and equipped with probes that target specifically L. pneumophila virulence factors and genes that are involved in the biosynthesis of lipopolysaccharide structures. Legionellae can be subgrouped on the basis of their lipopolysaccharide structures. Here, the usually phenotypic characterization of L. pneumophila Sg1 is successfully transmitted to a DNA-based genotypic method. Furthermore, the detailed validation of the DNA-microarray revealed a higher discriminatory power in comparison to the gold standard methods. It enables previously indistinguishable clones to be subdivided, providing valuable information about probable sources of infection.
The second new tool for typing of L. pneumophila is based on the core genome of the bacteria. An extended SBT-scheme was extracted from the core genome and accordingly named core genome multilocus sequence typing (cgMLST). This genome wide gene-by-gene typing approach allows a high genomic resolution of L. pneumophila isolates by retaining epidemiological concordance. A major advantage of this genome-based method is the detection of large recombination events within the analysed genomes, which is, so far, reserved for whole genome sequencing. The population structure of legionellae is largely driven by recombination and horizontal gene transfer rather than by spontaneous mutations. Therefore, the detection of recombination events is essential for typing of L. pneumophila isolates. In addition, the cgMLST-scheme assigns a core genome sequence type to the analysed isolate and allows backwards compatibility with the current SBT-scheme.
Both methods proved to be fast, reliable and robust typing methods through their application during outbreak investigations. Furthermore, both systems are particularly suited as routine molecular typing tools for the surveillance of single cases. The raw data are verified and translated into uniform portable codes, which enables the easy transfer and comparison of results. The standardized and portable quality of the results of both methods enables the establishment of a curated global database. This qualifies both methods as potential new gold standard methods for the genotyping of L. pneumophila isolates.
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Du, Bois Ilona [Verfasser], and Bernd [Akademischer Betreuer] Schmeck. "Identifikation von TNFAIP2 als Wirtsfaktor in der Legionellen-Infektion durch genomweite Chromatinanalyse / Ilona Du Bois. Betreuer: Bernd Schmeck." Marburg : Philipps-Universität Marburg, 2015. http://d-nb.info/1080298312/34.
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Ginevra, Christophe. "Détection par PCR multiplex de Clamoydophila pneumoniae, Mycoplasma pneumoniae et Legionelle et identification des Legionella par séquençage de l'espace intergénique séparant les ARNr 23S et 5S." Saint-Etienne, 2005. http://www.theses.fr/2005STET001T.
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Ce travail décrit l'intérêt de l'utilisation d'outils moléculaires pour le diagnostic et l'identification de bactéries pathogènes strictes du tractus respiratoire telles que Chlamydophila pneumoniae, Mycoplasma pneumoniae et les bactéries du genre Legionella. En premier lieu, une trousse de diagnostic moléculaire des infections par ces pathogènes a été développée conjointement par le laboratoire de bactériologie du CHU de Saint-Etienne et par la société Argène Biosoft. La détection repose sur une amplification génique multiplex suivie d'une révélation en microplaque par hybridation d'une sonde générique, permettant d'obtenir un résultat dichotomique : négatif ou positif pour une bactérie atypique, et par hybridation de sondes spécifiques de genre (Legionella) et d'espèces (C. Pneumoniae, M. Pneumoniae et L. Pneumophila) permettant d'identifier le pathogène détecté parmi les 3 recherchés. Cette trousse a été évaluée sur un ensemble de souches de référence et cliniques de ces 3 bactéries, par des études cliniques rétrospectives et prospectives ainsi que dans le cadre d'un contrôle de qualité international. Dans un deuxième temps, une méthode d'identification au niveau de l'espèce des bactéries du genre Legionella a été mise au point. L'espace intergénique séparant les ARN ribosomaux 23S et 5S a été choisi comme marqueur taxonomique ; cette région est amplifiée par PCR en temps réel à l'aide d'amorces spécifiques, séquencée et comparée aux séquences des bases de données, permettant une identification rapide des Legionella. L'amplification peut être réalisée directement à partir de prélèvements de patients atteints de légionellose, ce qui permet de s'affranchir de l'étape d'isolement de la bactérie parfois difficilement réalisable dans ce type d'infections.
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Makin, Thomas. "Legionellae and the hospital environment." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261833.
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This thesis investigates the distribution of legionellae in water systems in the Royal Liverpool University Hospital (RLUH) and examines some of the factors that affect colonisation by these organisms. The effect of persistent contamination of the domestic water system on immunocompromised patients was monitored, and the envirorunental control of legionellae by various methods was assessed. A fluorescent monoclonal antibody (DFA) was evaluated for its ability to detect L. pneumophila in domestic and cooling water, and was highly sensitive and specific for this purpose. DFA detected non-culturable L. pneumophila in the cold water system (CWS) that were not recovered following heat shock procedures. Legionellae were not isolated from air conditioning humidifiers, and were rarely detected in cooling towers despite treatment with inadequate concentrations of biocide. A high pH assisted in preventing legionella colonisation. Calorifier sediment contained legionellae and high levels of insoluble copper oxides. Culture media and a low pH, released Cuions from sediment which were markedly inhibitory to legionellae. Low concentrations of Cuions were detected in domestic hot water. At temperatures below 60°C legionellae were detected in the hot water supply to the wards, and calorifiers were regularly re-seeded by legionellae returning from contaminated peripheral parts of the system. Legionellae were not detected in the HWS when 60°C was achieved. L. pneumophila sgps 6, 12 and L. bozemanii predominated in domestic water. L. pneumophila sgp 1 was detected on one occasion only in a cold water storage tank and a calorifier, and did not colonise any of the water systems. L. pneumophila sgps 6 and 12 were isolated from three nosocomial cases of Legionnaires' disease. Endemic legionellae prepared as yolk sac antigens, detected significant titres of legionella antibodies (~ 1 :64) in samples from six subjects which did not react ( < 1: 16) with the PHLS L. pneumophUa sgp 1 yolk sac antigen. Most raised titres were to L. pneumophila sgp 12, and the highest titre in heterologous responses identified the infecting serogroup of L. pneumophila. Routine culture of respiratory samples from susceptible patients. detected only one undiagnosed case of Legionnaires' disease. Legionellae were not detected in water from showers that were regularly flushed or irradiated with UV light. Re-colonisation of showers by legionellae was closely associated with the reappearance of amoebae. A trace heating element was effective at maintaining dead-legs at 50°C (± 1.5) and reduced legionellae in these sites. Legionellae proliferated where pipes and heating element were not adequately insulated. Re-circulating the HWS through dead-legs eradicated legionellae from this site but resulted in heavy colonisation of adjacent mixer valves. Automatic drain valves failed to prevent legionellae from colonising shower hoses and mixer valves, and hyperchlorination of shower hoses and water strainers had only a short term effect. Showers heated electrically at point of use were not colonised by legionellae entering in the CWS, or by wild strains of legionellae introduced with calorifier sediment. This appeared to be due to rapid throughput of water, extensive use of copper, and pasteurisation of calorifier contents following discharge of heat from the heating elements, after the shower ceased operating.
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RHINN, ISABELLE. "Hydrobiologie et prophylaxie des legionelles en milieu hospitalier." Strasbourg 1, 1991. http://www.theses.fr/1991STR15022.
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Revillet, Marie-Christine. "Lectine-adhésine de Legionella pneumophila." Lyon 1, 1991. http://www.theses.fr/1991LYO1T077.
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Weber, Stephen. "Phosphoinositide modulation during Legionella pneumophila infection." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-183828.
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Ha, Thi-Lan Gehin Evelyne. "Étude de l'aérosol de Legionella pneumophila." Créteil : Université de Paris-Val-de-Marne, 2007. http://doxa.scd.univ-paris12.fr:8080/theses-npd/th0394062.pdf.
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Thèse de doctorat : Physique des aérosols : Paris 12 : 2005.Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de l'écran-titre. Bibliogr. : 246 réf.
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Ha, Thi-Lan. "Étude de l'aérosol de Legionella pneumophila." Paris 12, 2005. https://athena.u-pec.fr/primo-explore/search?query=any,exact,990003940620204611&vid=upec.
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D'origine hydrique, Legionella est une cause de pneumonies environnementales. L'exposition infectante se fait via la formation d'un aérosol biologique à partir de milieux colonisés. Ce vecteur de propagation constitue le champ d'investigation de l'étude axée sur la survie du modèle pathogène, Legionella pneumophila. Ces travaux démontrent la létalité bactérienne occasionnée par l'aérosolisation. Un effet majeur de l'humidité relative est observé. Il apparaît variable avec l'âge de l'aérosol, mettant en avant l'action létale de la dessiccation combinée à la présence de l'oxygène de l'air. Sous l'effet de la désydratation, l'exposition environnementale conduit rapidement à la perte de cultivabilité des cellules aérosolisées. Néanmoins, l'intégrité de leur structure membranaire suggère le maintien d'une viabilité. Des facteurs intrinsèques à la souche, l'état métabolique, l'âge cellulaire ou le type bactérien, imputent également sur la résistance du microorganisme disperséLegionella, an aquatic microbe, is responsible for environmental pneumonias. Infection is caused by inhalation of a bioaerosol produced from colonized habitats. This vector of propagation constitutes the field of investigation of the study, which is centered on the survival of the pathogenic model, Legionella pneumophila. This work shows the bacterial lethality caused by the aerosolization. A major effect to relative humidity is observed. It appears variable with age of aerosol. This suggests an action of desiccation combined with the presence of oxygen in air. Under dehydratation, environmental exposure leads quickly to the loss of cultivability of the aerosolized cells. Nevertheless, integrity of their membrane structure suggests viability preservation. Strain factors such metabolic state, cellular age or bacterial type, also influence on resistance of dispersed microorganism. Study of Legionella pneumophila in aerosol
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Finidori, Jean-Paul. "Coxiella burnetii - legionella pneumophila : reactions croisees ?" Aix-Marseille 2, 1989. http://www.theses.fr/1989AIX20906.
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Lewis, Valérie. "Techniques actuelles d'isolement des légionelles dans le milieu hydrique." Paris 5, 1990. http://www.theses.fr/1990PA05P219.
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Lelogeais, Virginie. "Étude de l’interaction entre L. pneumophila et l’autophagie de la cellule hôte." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1168/document.
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L. pneumophila est l'agent responsable de la légionellose, une pneumonie sévère associée à 10% de mortalité. Cette bactérie intracellulaire a acquis la capacité de survivre et de se répliquer dans des cellules humaines. Notamment, L. pneumophila sécrète un grand nombre d'effecteurs par son système de sécrétion de type IV, qui interagissent avec différentes voies cellulaires, dont l'autophagie. L'autophagie est une voie de dégradation conservée qui permet aux cellules eucaryotes de réguler l'homéostasie cellulaire et d'éliminer les agents pathogènes intracellulaires. Néanmoins, nombre d'entre eux ont évolué pour manipuler cette voie à leur propre avantage. Même si l'interaction entre L. pneumophila et l'autophagie a été rapportée, aucun modèle clair n'est déterminé. Dans cette étude, nous montrons qu'une infection à L. pneumophila induit une stimulation globale de l'autophagie, mais que ce phénotype dépend des souches utilisées, et notamment de la présence de certains effecteurs. De plus, l'inhibition de l'autophagie est liée à un défaut de réplication intracellulaire suggérant que cette voie est bénéfique à la bactérie. Afin de rechercher les déterminants génétiques impliqués dans cette interaction, nous avons identifié des effecteurs communs sécrétés par le système de sécrétion de type IV entre L. pneumophila et Coxiella burnetii, une bactérie de l'ordre des Legionellales connue pour stimuler et détourner l'autophagie. La capacité des mutants de ces effecteurs à stimuler l'autophagie chez L. pneumophila a été analysée. Si aucun d'entre eux ne semble impliqué dans la modulation de l'autophagie, cette étude suggère d'autres fonctions pour ces effecteurs conservésLegionella pneumophila is responsible for the legionellosis disease, a severe pneumonia associated with 10% mortality rate. This intracellular bacterium has evolved the ability to survive and replicate within human cells. Notably, L. pneumophila secretes a high number of type IV secretion system effectors that interfere with many cellular pathways including autophagy. Autophagy, a highly conserved degradative pathway, allows eukaryotic cells to regulate cell homeostasis and fight intracellular pathogens. Nevertheless numerous microorganisms have evolved strategies to subvert this mechanism to their own advantage. The interaction between L. pneumophila and autophagy has been reported but remains unclear. In this study, we show that L. pneumophila infection induces a global stimulation of autophagy, but importantly this autophagy stimulation depends on the bacterial strain. Moreover, we also observed that inhibition of autophagy results in decreased intracellular bacterial proliferation suggesting that host cell autophagy is benificial for L. pneumophila. In order to decipher the molecular determinants involved in the interaction with autophagy, we identified common effectors secreted by the type IV secretion system between L. pneumophila and Coxiella burnetii, a bacterium from the order Legionellale responsible for Q fever and known to stimulate and hijack host cell autophagy. Mutant of these common effectors in L. pneumophila were analysed. While, none of them seems to be implicated in autophagy modulation, this study suggests other functions for these conserved effectors
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Johansson, Andreas, and Alex Hansson. "Legionella : En risk som bör beaktas ombord?" Thesis, Linnéuniversitetet, Sjöfartshögskolan, SJÖ, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-18444.
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Legionellabakterien orsakar den så kallade legionärssjukan vilken är en form av lunginflammation med hög dödlighet. Bakterien lever i färskvatten och finns naturligt i våra sjöar och vattendrag. Enligt Smittskyddsinstitutet trivs Legionellabakterien i temperaturintervallet 20°C till 42°C med en optimal tillväxt vid 35°C, bakterien lever dock redan från 0°C. Vi har i denna undersökning försökt utreda om legionella kan vara en risk ombord i fartyg. Eftersom tester för förekomsten av legionellabakterier inte ingår i de krav som ställs på dricksvattenkvaliteten ombord, har vi kontaktat fem rederier för att fråga om de har utfört några utökade tester där legionella ingår. Av dessa fem rederier hade tre aldrig testat sitt dricksvatten för legionella och två hade testat och påträffat legionella. Då många av de komponenter som ingår i dricksvattenförsörjningen var placerade i maskinrummet där en omgivningstemperatur mellan 20°C - 42°C var vanligt förekommande, och det faktum att dricksvattensystemen ombord ofta var långa med många tappställen som kunde ge upphov till stillastående vatten, kunde det konstateras att legionella mycket väl kan vara en risk ombord.The Legionella bacteria cause the so called Legionnaires' disease which is a form of pneumonia with high mortality. The bacterium lives naturally in freshwater lakes and other freshwater sources. According to Smittskyddsinstitutet the bacteria thrives in the temperature interval 20°C - 42°C with an optimal growth at 35°C. However, the bacteria can live in temperatures down to 0°C. In this study we have tried to determine if legionella could be a risk onboard ships. Since testing for legionella bacterium is not required according to regulations, we decided to contact five shipping companies in order to establish if they have ever taken any tests for legionella. Three of those shipping companies had never tested for legionella the other two had tested and found legionella in their drinking water system. Since many components included in the drinking water system were placed in the engine room where the ambient air temperature usually is between 20°C - 42°C, and the fact that the drinking water system often includes long piping’s and many consumers which can lead to standing water, we could conclude that legionella very well could be a risk onboard.
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Finsel, Ivo. "Characterisation of the Legionella pneumophila effector RidL." Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-169685.
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The Gram-negative bacterium Legionella pneumophila naturally parasitises environmental amoebae, but is also able to infect human alveolar macrophages in a mechanistically similar manner. This can result in the mild "Pontiac fever", a flu-like illness, or a potentially lethal pneumonia termed Legionnaires' disease". Crucial for establishing an intracellular replication niche is the Icm/Dot type IV secretion system (T4SS), which translocates approximately 300 different "effector" proteins into the host cell. These substrates enhance uptake efficiency into phagocytes and direct formation of a replication-permissive compartment, called the Legionella-containing vacuole (LCV), and ultimately the egress of the bacteria. Some of the effectors interfere with small GTPases, phosphoinositide metabolism or the ubiquitination machinery, and modulate host cell signalling and vesicle trafficking.
We developed a method to isolate intact LCVs by using immuno-magnetic separation with an LCV-specific antibody followed by density gradient centrifugation. Proteomic analysis of the purified phagosomes together with findings of previous studies showed, that the vacuoles harbour markers of the endosomal network, associate with mitochondria, early secretory vesicles and the endoplasmic reticulum, but avoid fusion with lysosomes.
Our investigations of the novel L. pneumophila effector RidL revealed that the LCV also communicates with the retrograde vesicle trafficking pathway of infected cells. This pathway recycles amongst others acid-hydrolase receptors, such as the cation-independent mannose 6-phosphate receptor (CIMPR), from the tubular endosomal network back to the trans-Golgi. This transport requires the multiprotein "retromer" complex, which consists of two major subunits: the heterotrimeric cargo-selective subcomplex comprising the proteins Vps26, Vps29 and Vps35 and the membrane-deforming heterodimeric subcomplex composed of any combination of the phosphoinositide (PI)-binding sorting nexins SNX1 or SNX2 plus SNX5 or SNX6.
Pull-down experiments with lysates of RAW 264.7 macrophages or D. discoideum amoebae revealed Vps26, Vps29 and Vps35 to be retained by the then uncharacterised protein RidL, which represented an intriguing, novel effector interaction. Like most T4SS substrate mutants, L. pneumophila lacking ridL showed no phenotype for growth in liquid AYE medium and uptake into phagocytes compared to wild-type bacteria. However, intracellular replication was strongly impaired for the mutant strain in several host cell lines. RidL is preferentially expressed in the late post-exponential growth phase and translocated in an T4SS-dependent manner at early time-points of the infection, suggesting a role shortly after the uptake of the bacteria. The effector exhibited a bipolar localisation on the LCV membrane, but upon overexpression the protein covered the entire vacuole. Interestingly, RidL bound the lipid phosphatidylinositol 3-phosphate (PtdIns(3)P), a known eukaryotic endosomal membrane anchor, and also specifically bound to the retromer subunit Vps29. Although the protein had no effect on the acquisition of Vps26, Vps29 and Vps35, the percentage of LCVs positive for the retrograde cargo receptors CIMPR or sortilin was reduced in presence of RidL, suggesting interference with the retrograde transport pathway. Furthermore, significantly less SNX1- and SNX2-positive LCVs were detected in cells infected with wild-type L. pneumophila compared to the ridL mutant strain. Moreover, RidL competed with SNX1 for binding at PtdIns(3)P-positive membranes. To directly examine the influence of RidL on retrograde trafficking, the retromer-dependent transport of cholera and Shiga toxin inside cells was analysed in macrophages infected with wild-type or ridL L. pneumophila, and in HeLa cells ectopically producing RidL, respectively. In both cases, the trafficking was inhibited by RidL, and for cholera toxin the transport was arrested at the endosomal stage. In line with these findings, siRNA knockdown experiments revealed that a functional retrograde pathway restricted intracellular growth of L. pneumophila.
Taken together, we postulate that RidL (Retromer interactor decorating LCVs) inhibits retrograde trafficking at endosomes by binding to the retromer subunit Vps26 and/or by competition with sorting nexins, thus promoting intracellular replication of L. pneumophila.
Collectively, the results obtained in this thesis shed light on the host factor composition of LCVs and provide mechanistic insights into a novel L. pneumophila effector protein.
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Lahwal, Abdulla Mohammed. "Virulence studies on Legionella pneumophila serogroup 1." Thesis, University of Liverpool, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307618.
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Boswell, Timothy Charles John. "The serological crossreaction between legionella and campylobacter." Thesis, King's College London (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267616.
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Zeigler-Ballerstein, Stephanie Denise Barbaree James M. "Evaluation of intercellular signaling in Legionella pneumophila." Auburn, Ala, 2009. http://hdl.handle.net/10415/1904.
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Rawkins, Ann. "Virulence and pathogenic mechanisms of Legionella pneumophila." Thesis, Open University, 1994. http://oro.open.ac.uk/54371/.
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Strains of Legionella pneumophila which were virulent for guinea pigs were passaged on laboratory media such that they became avirulent. Virulent/avirulent pairs of strains were compared in an attempt to identify potential virulence or pathogenic factors. Virulent forms multiplied within guinea pig alveolar macrophages maintained in tissue culture over 48 hours and phagosome lysosome fusion was not inhibited in these macrophages. Avirulent strains did not multiply but those produced by passage on supplemented Mueller Hinton agar (MHIH) maintained viability whereas those produced by passage on buffered charcoal yeast extract agar (BCYE) were killed. Virulent legionellae produced more flagella than their paired avirulent forms but it was considered unlikely that this was related to pulmonary virulence. Minor differences in outer membrane proteins and reactivity with various antisera were observed between virulent/avirulent pairs but these were not consistent between the L.pneumophila strains and no virulence-associated proteins were found. The lipopolysaccharide and extracellular enzyme activities of the pairs of strains were indistinguishable. The Corby strain of L.pneumophila (CV) was isolated from its intracellular in vivo environment and these bacteria compared with the same strain grown on BCYE. The in vivo-grown CV showed no change in uptake by, or intracellular replication within, alveolar macrophages but, when Western blotted and incubated with various antisera, the two types of bacteria reacted differently. There was a reduced reaction by the CV grown in vivo, suggesting a change in the number and/or type of proteins expressed when exposed to an intracellular environment. The cellular responses in the lungs of guinea pigs immediately following aerosol challenge with virulent and avirulent forms of the Corby strain were compared. The avirulent forms evoked little change in the alveolar cell populations whereas an inflammatory response to CV occurred. Polymorphonuclear Ieucocytes (PMNLs) were the principal cell type involved and the initial increase in numbers of this cell type corresponded with a transient decrease in the viablility of CV, providing evidence that virulent L.pneumophila are killed by PMNLs. The multiplication of CV which followed suggested a developing resistance to the killing. Numbers of avirulent Corby decreased rapidly and, for the MHIH passaged form (CA), this was in contrast to its intracellular survival in vitro. An attempt was made to follow the changes in cellular responses using immunolabelling techniques and flow cytometry. Difficulties with obtaining consistent, sequential samples did not allow a full interpretation of the results but the technique showed promise for such studies. The tissue destructive protease (TDP) of L.pneumophila was shown to degrade or inactivate gamma interferon, IgG and possibly interleukin 2, proteins of possible significance to the host in protection against infection with L.pneumophila. Inhibition of TDP by the protease inhibitor a2 macroglobulin was demonstrated and, prophylactic treatment of guinea pigs with the inhibitor resulted in prolonged survival (compared with untreated controls) following aerosol challenge with CV. Intracellular production of TDP by L.pneumophila multiplying within guinea pig alveolar macrophages was demonstrated by ELISA and immunogold labelling and functional activity of the enzyme purified from infected guinea pig lungs was shown. A mutant of L.pneumophila, deficient in TDP production, was compared in the guinea pig model with its TDP-producing parent and CV. The mutant and parent were considerably less virulent than CV but, despite the deficiency in TDP production, the mutant was lethal for guinea pigs. The lung damage caused by the mutant was less severe than that caused by the parent or CV and it was suggested that progression of disease and cause of death was not typical of Legionnaires' disease. An immunocompromised mouse model of Legionnaires' disease was investigated using aerosol infection of severe combined immune deficient (SeID) mice. SCID mice did not become ill when given a potentially lethal aerosol of L.pneumophila and alveolar macrophages of these mice did not support the growth of L.pneumophila in vitro. SCID mice which had been reconstituted with human leukocytes were susceptible to aerosol challenge and developed lung lesions similar to those seen in guinea pigs and humans.
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Moliner, Claire. "Caractéristiques génétiques d'un pathogène d'amibe : Legionella Drancourtii." Aix-Marseille 2, 2009. http://www.theses.fr/2009AIX20685.
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Les amibes sont des phagocytes sauvages se nourrissant de particules présentes dans leur environnement, dont des virus et des bactéries. Certains de ces microorganismes, pathogènes potentiels, se sont adaptés pour résister à cette phagocytose et parfois à la vie intra-amibienne. Contrairement aux autres pathogènes intracellulaires, les microorganismes intra-amibiens ne sont pas spécialisés et vivent dans un milieu polymicrobien. Pour étudier l’impact de leur mode de vie sur leur génome, nous avons entrepris le séquençage d’un nouveau pathogène d’amibe, Legionella drancourtii. La taille conséquente de son génome, 4,06 Mb, plus grande que celle des autres membres du genre Legionella, est une caractéristique retrouvée chez tous les intra-amibiens, suggérant que la théorie de l’évolution réductive des bactéries intracellulaires ne s’applique pas à ces microorganismes. De plus, L. Drancourtii a acquis de nombreux gènes de microorganismes intra-amibiens ou de bactéries de l’eau, ce qui a augmenté la taille de son génome. Ce taux élevé de transfert latéral de gènes est retrouvé chez tous les intra-amibiens, suggérant que l’amibe est un lieu d’échange génique. Nous avons démontré que ces amibes jouaient également un rôle direct dans ces transferts géniques. Des systèmes importants pour le transfert de gène et la pathogénicité ont ainsi pu être acquis, tels que le système de sécrétion de type IV et des séquences répétées comme les «ankyrin repeats». Toutes ces caractéristiques suggèrent que les amibes sont un «melting pot» de gènes que les microorganismes intra-amibiens utilisent pour s’adapter, par une même voie évolutive, à leur biotope ou créer de nouveaux pathogènes. Du fait de cette adaptation, les amibes constituent pour les bactéries pathogènes qu’elles hébergent un vecteur de transmission, notamment pour les Legionella. Ces bactéries provoquant chez l’homme des pathologies sévères pouvant causer la mort, nous avons développé une base de données de profils protéiques des différentes espèces pathogènes reconnues qui permet d’établir une identification rapide et fiable des isolats cliniques par spectrométrie de masse.
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Loza, Correa Maria. "Rôle de l’opéron kai chez Legionella pneumophila." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T055.
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Legionella pneumophila est un pathogène opportuniste avec un cycle de vie intracellulaire obligatoire, ils arrivent à se répliquer dans leurs cellules hôtes comme des protozoaires, en exploitant les protéines et les voies de signalisation de l’organisme infecté pour échapper à sa réponse immunitaire. L. pneumophila est décrite comme un organisme sans oscillations circadiennes, pourtant elle possède des gènes homologues aux gènes circadiennes kaiBC de cyanobactéries. En appliquant un système d’infections in vitro et in vivo ainsi qu’une approche de génomique comparative et fonctionnelle sur l’ organisme modèle Legionella pneumophila mon projet a pour objectif de caractériser le rôle des gènes kaiBC de L. pneumophila. Les protéines KaiABC de cyanobactéries encodent un oscillateur circadien permettant la coordination et l’optimisation temporelle de divers processus biologiques ainsi que l’adaptation aux fluctuations quotidiennes (comme la production d’oxygène via la photosynthèse pendant le jour et la fixation d’azote dans l’obscurité). Notre étude montre que kaiC, kaiB, avec le lpp1114 (codant pour une protéine à plusieurs domaines), l’ensemble constitue une unité transcriptionnelle sous la commande du facteur sigma RpoS. Les souches mutantes de l'opéron kai affichent une haute sensibilité sous conditions de stress par le paraquat ou le sel en comparaison avec la souche sauvage. En effect, nos données provenant d’une expérience utilisant des systèmes de double hybride suggèrent que les proteines KaiC et KaiB de L. pneumophila n’interagissent pas comme ceux de cyanobactéries. Cependant, une version étendue de L. pneumophila KaiB contenant des résidus de C-terminal de T. elongatus est capable d’interagir avec KaiC. Nous démontrons aussi que la structure cristalline de KaiB de L. pneumophila révèle un pliage pareil a ceux de thiorédoxine (protéine d'oxydoréduction) mais manque les résidus de l'extrémité C-terminale important pour l'interaction avec KaiC. En revanche, L. pneumophila KaiC conserve l'activité d'autophosphorylation, mais KaiB ne declénche pas la phosphorylation de KaiC comme chez les cyanobacteries. L'analyse phylogénétique des protéines de Kai indique qu'elles ont été transférés à L. pneumophila et ont évolué de Synechosystis KaiC2B2 et pas du copie circadienne KaiB1C1. Il semble que les protéines Kai de L. pneumophila améliorent son adaptation à des conditions stressantes et aux changements environnementauxLegionella pneumophila is an opportunistic pathogen with an intracellular life cycle that uses aquatic protozoa as replication niche and protection from harsh environments. Although L. pneumophila is not known to have a circadian clock, it encodes homologues of the KaiBC proteins of Cyanobacteria that regulate circadian gene expression. By using a wide range of in vitro, in vivo and in silico approaches I characterized the KaiB and KaiC proteins of L. pneumophila The proteins KaiABC of cyanobacteria coordinate a circadian oscillator that regulates many physiological functions in the cells according to the day and the night time induce by the rotation of the Earth (e.g. they do photosynthesis during the day and nitrogen fixation during the night). We show that L. pneumophila kaiB, kaiC and the downstream gene lpp1114, are transcribed as a unit under the control of the stress sigma factor RpoS. Mutant analyses revealed that the kai operon-encoded proteins increase fitness of L. pneumophila in competitive environments, and confer higher resistance to oxidative and sodium stress. Indeed, KaiC and KaiB of L. pneumophila do not interact as evidenced by yeast and bacterial two- hybrid analyses. Fusion of the C-terminal residues of cyanobacterial KaiB to Legionella KaiB restores their interaction. The crystal structure of L. pneumophila KaiB suggests that it is an oxidoreductase-like protein with a typical thioredoxin fold. In contrast, KaiC of L. pneumophila conserved autophosphorylation activity, but KaiB does not trigger the dephosphorylation of KaiC like in Cyanobacteria. The phylogenetic analysis indicates that L. pneumophila KaiBC resemble Synechosystis KaiC2B2 and not the circadian KaiB1C1 copy. Thus, the L. pneumophila Kai proteins do not encode a circadian clock, but enhance stress resistance and adaption to changes in the environments
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Doyle, Robyn Michelle. "Molecular analysis of Legionella longbeachae serogroup 1 virulence." Title page, contents and summary only, 2000. http://web4.library.adelaide.edu.au/theses/09PH/09phd7546.pdf.
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Bibliography: leaves 246-304. Describes experiments aimed at characterising the potential virilant factors of Legionella longbeachae sg 1, an important human pathogen which is responsible for nearly half of all clinical cases of Legionella related pneumonia reported each year.
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Sanden, Gary Noble. "Disinfection of potable-quality water containing Legionella pneumophila." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/25377.
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Boissinot, Maurice. "Analyse antigénique de la membrane externe de Legionella pneumophila serogroupes 1 à 8." Master's thesis, Université Laval, 1985. http://hdl.handle.net/20.500.11794/33498.
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Les protéines de la membrane externe de Leqionella pneumophila sérogroupes 1 à 8 ont été préparées, à partir d'un lysat bactérien, par solubilisation sélective au lauryl sarcosinate de sodium. Les protéines ainsi obtenues ont été séparées par électrophorèse sur gel de polyacrylamide en présence de dodécyl sulfate de sodium (SDS-PAGE) et transférées sur des feuilles de nitrocellulose. Des antisérums de lapin dirigés contre chacun des 8 sérogroupes de L. pneumophila ont été obtenus en immunisant chaque animal avec des bactéries vivantes. Les protéines tranfé- rées ont été révélées avec ces antisérums et des immunoglobulines de porc anti-immunoglobulines de lapins marquées à la peroxidase. Des déterminants antigéniques communs aux 8 sérogroupes ont été trouvés dans au moins 2 antigènes de la membrane externe (29 Kd et 45 Kd). Cependant, des expériences d'absorptions croisées ont révélé que ces antigènes auraient des déterminants antigéniques différents selon le sérogroupe. Ces résultats ne sont pas incompatibles avec ce que l'on connaît des protéines de la membrane externe des autres bactéries. Toutefois, certains indices nous laissent croire que notre préparation de protéines a pu être contaminée avec du lipopolysaccharide. Ceci expliquerait pourquoi les relations antigéniques observées avec les bandes de 29 et 45 Kd correspondent bien avec celles observées par immunofluorescence.Montréal Trigonix inc. 2018
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Ader, Florence. "Physiopathologie de l’infection à Legionella pneumophila dans un modèle expérimental murin." Lyon 1, 2008. http://www.theses.fr/2008LYO10023.
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Dans le but d’étudier la physiopathologie de l’infection à Legionella pneumophila, nous avons exploré l’interaction hôte-pathogène in vitro sur des cultures de pneumocytes humains et in vivo dans un modèle expérimental de souris A/J sous deux aspects : l’étude de la lésion de la barrière alvéolo-capillaire et l’étude de la réponse inflammatoire pulmonaire. Ces approches ont été appliquées à trois phases expérimentales : i) l’étude des mécanismes impliqués dans l’adhérence de L. Pneumophila à l’épithélium respiratoire ; ii) l’étude du rôle d’un facteur de virulence : le système de sécrétion de type IV (système Dot/Icm) ; iii) la caractérisation de la réponse épithéliale innée. Les principales conclusions issues des présents travaux sont : -in vitro, l’ion divalent zinc est un co-facteur important de l’adhérence de L. Pneumophila aux pneumocytes de type II alvéolaires via une adhésine bactérienne protéique. -In vivo, le polysacharide sulfaté héparine administré par voie intratrachéale exerce un effet protecteur vis-à-vis du développement d’une infection à L. Pneumophila suggérant un mécanisme d’adhérence médié par une adhésine bactérienne se fixant aux chaînes d’héparane sulfate des glycosaminoglycanes sulfatés de la surface épithéliale. -In vivo, le système Dot/Icm de L. Pneumophila des souches du sérogroupe 1 Lens et Paris est un facteur de virulence important pour la constitution de l’agression pulmonaire. Son expression est significativement associée aux modifications de perméabilité de la membrane alvéolo-capillaire, à la multiplication bactérienne intra-pulmonaire et à la dissémination systémique. In vivo, à 4 et 48 heures après l’infection par L. Pneumophila, on mesure une expression constitutive, stable du gène de la -défensine mBD-1 et une expression croissante du gène de la -défensine mBD-3 confirmant son caractère inductible attestant d’une réactivité épithéliale vis-à-vis du pathogène. Par ailleurs, nous avons observé une absence d’expression du gène de la chémokine ccl20, médiateur clef pour le recrutement des cellules dendritiques au début de l’infectionTo progress in the understanding of L. Pneumophila infection, we investigated host-pathogen interaction in vitro through lung epithelial cell cultures and in vivo through an A/J murine model focusing on two aspects: the studies of alveolar-capillary barrier injury and lung inflammatory response. Three parts have been developed: 1) a study of the mechanisms leading to L. Pneumophila attachment to respiratory epithelia; 2) a study of virulence factor type IV secretion system (Dot/Icm system) involvement in L. Pneumophila pathogenesis; 3) a primary characterization of mucosal innate response. The main results of this work are : -in vitro, the zinc ion is an important co-factor of L. Pneumophila adherence to alveolar type II pneumocytes via a protein adhesin. -In vivo, sulphated saccharide heparin co-instilled intratracheally with L. Pneumophila challenge has a protective effect on the alveolar-capillary barrier and prevents bacterial dissemination. It tends to confirm the competitive inhibition by heparin of L. Pneumophila attachment to lung epithelium in vivo, and point to the possible involvement of a heparan-sulfate adhesin in L. Pneumophila binding to pneumocytes. -In vivo, L. Pneumophila Dot/Icm system of serogroup 1 strains Lens and Paris is central to pathogenesis and is associated with the development of acute lung injury, lung bacterial replication and systemic spread. -In vivo, at 4 and 48 hours post-infection by L. Pneumophila both gene expressions of lung -defensins mBD-1 and mBD-3 were detected in a constitutive and inducible way respectively. However, the absence of ccl20 gene expression was observed, a key chemokine for dendritic cells recruitment after bacterial infection
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Aurell, Helena. "Detection, identification and typing of clinical and environmental Legionella strains." Lyon 1, 2003. http://www.theses.fr/2003LYO10126.
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La légionellose est une pneumonie fréquente provoquée par l'inhalation d'un aérosol contaminé par Legionella. Pour la détection de L. Pneumophila dans l'eau, nous avons développé une méthode rapide et sensible utilisant la cytométrie en phase solide. Par la comparaison de la prévalence des espèces et des sérogroupes parmi des souches cliniques et environnementales, nous avons montré une répartition différente, ce qui suggère que certaines souches sont plus pathogènes. Afin d'identifier la source environnementale de la contamination, le typage par électrophorèse en champs pulsé (PFGE) est nécessaire. L'analyse des profils en PFGE a démontré que la souche endémique Paris avait une prévalence importante et était distribuée en France et en Europe. L'étude des souches sporadiques, épidémiques et endémiques par séquençage de gènes a montré que le fond génétique n'expliquait pas la différence de pathogénicité ; d'autres facteurs pourraient être impliqués.
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Albert-Weißenberger, Christiane. "Regulation of the Flagellar Biogenesis in Legionella pneumophila." kostenfrei, 2008. http://www.opus-bayern.de/uni-wuerzburg/volltexte/2009/3433/.
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Watkins, I. D. "Monoclonal antibodies to Legionella pneumophila and related organisms." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354879.
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Halgunset, Anders. "Typing av Legionella pneumophila med MALDI-TOF MS." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bioteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24697.
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Legionella pneumophila er fakultativ intracellulære bakterier som lever naturlig i akvatiske habitater. De kan replikere i makrofager og protozoer, bli overført til mennesker gjennom areosoler og føre til smitte. Ved eventuelle utbrudd er det viktig å kunne identifisere kilden, noe som i dag bli gjort ved å typebestemme L. pneumophila med sekvensbasert typing (SBT). Samtidig har matrix-assisted laser desorption/ionization ? time-of-flight (MALDI?TOF) mass spectrometry (MS) vist seg å kunne brukes til rask og effektiv identifisering av en rekke mikroorganismer på artsnivå, deriblant Legionella. Hos enkelte andre mikroorganismer har MALDI?TOF MS også vist å kunne skille mellom underarter. MALDI?TOF MS ble i denne oppgaven benyttet for å undersøke om det var mulig å skille L. pneumophila fra hverandre på stammenivå ved hjelp av MALDI Biotyper 3.0 programvare. Standardprotokollen anbefalt av Bruker Daltonics for proteinekstraksjon fra mikroorganismer ble tilpasset/optimalisert for bruk på L. pneumophila, slik at reproduserbare massespektre ble oppnådd. Evalueringen viste at proteinekstraksjon fra ca 2 µl biologisk materiale med 10 µl acetonnitrill og 10 µl maursyre, ga best scoreverdi opp mot Bruker Daltonics referansebibliotek. Den optimale temperaturen og varigheten for dyrkning ble vist å være henholdsvis 37 ˚C og 48 ± 2 timer. Det ble vist at lagring av skåler/kolonier med L. pneumophila ved 37 ˚C førte til forandringer i massespektrene, mens lagring ved 20 ˚C ikke medførte slike forandringer og at stabile massespektre ble oppnådd etter seks dagers lagring.Det ble bygget opp et referansebibliotek i MALDI Biotyper 3.0 bestående av referansespekter/referansetopplister (MSP) fra til sammen 48 Legionella spp. hvorav 41 var L. pneumophila -isolater. Med referansebiblioteket ble det vist at MSP (dannet ved standard innstillinger) for mange L. pneumophila var for like hverandre til å gi identifisering mot egne MSP. En klyngeanalyse ble brukt i sammenligning av L. pneumophila mellom SBT og MSP fra referansebiblioteket dannet med MALDI?TOF MS. Sammenligningen viste at diversiteten i proteinsammensetningen hos L. pneumophila, representert som MSP, ikke ga samme oppløselighet som gjennom sekvensvariasjonene fra genene i SBT -analysen.
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Auraß, Philipp. "Charakterisierung Patatin-ähnlicher Proteine des Lungenpathogens Legionella pneumophila." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15977.
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Legionella pneumophila ist ein fakultativ intrazellulär replizierendes Bakterium und der Erreger der Legionärskrankheit, einer schweren Pneumonie. Das Typ IVB Dot/Icm Proteinsekretionssystem und dessen Effektoren sind wesentlich an der Virulenz des Bakteriums beteiligt. Das Ziel der vorliegenden Arbeit war die Charakterisierung der Patatin-ähnlichen Proteine von L. pneumophila - insbesondere von PatA, das vom Dot/Icm Sekretionssystem in Wirtszellen eingeschleußt wird. Im Rahmen dieser Arbeit wurden folgende Ergebnisse erzielt: Die 11 Patatin-ähnlichen Proteine von L. pneumophila zeigen hauptsächlich Lysophospholipase A-Aktivität. PatA besitzt außerdem Phosphatidylglyzerol-spezifische Phospholipase A-Aktivität. Serin-72, welches in ein G-X-S-X-G Lipasemotiv eingebettet ist, ist für die Aktivität des Proteins essentiell. PatA ist nach Expression in A549 Epithelzellen in der Zytoplasmamembran oder einer damit eng assoziierten Struktur lokalisiert, die lipolytische Aktivität ist hierfür nicht entscheidend. Die Deletion einer C-terminalen Proteinregion führt zum Verlust der membranständigen Lokalisation. Virulenzattenuierte L. pneumophila Mutanten bilden unter Präsenz von Amöben - im Gegensatz zu Wildtypstämmen - eine Koloniemorphologie aus, die Scattermorphologie genannt wurde. Auf Basis der Scattermorphologie wurde eine Transposon-mutagenisierte Legionella Klonbank auf Wirtszellkolonisationsdefekte überprüft. Dabei wurden 119 kolonisationsdefekte Mutanten isoliert und 70 neue putative Wirtszellkolonisationsgene, darunter zwei Gene Patatin-ähnliche Proteine (patD, patF), identifiziert. patD befindet sich in einem Operon mit bdhA, dem Gen einer putativen 2-Hydroxybutyrat-Dehydrogenase. Das Operon spielt eine Rolle im Poly-Beta-Hydroxybutyrat (PHB) Stoffwechsel des Bakteriums und wird für die Replikation in Wirtszellen benötigt. Die Studie liefert die ersten experimentell fundierten Ergebnisse, die die Bedeutung des PHB-Metabolismus für die Virulenz des Bakteriums belegen.Legionella pneumophila is the causative agent of Legionnaires’ disease, a potentially fatal pneumonia. One mayor virulence determinant is the Dot/Icm Type IVB secretion system and its effector proteins. Aim of the present work was the characterization of patatin-like proteins of L. pneumophila, and in particular PatA, which is carried by the Dot/Icm secretion system into host cells. Within this work following results were obtained: The 11 patatin-like proteins of L. pneumophila possess majorly lysophospholipase A activity. L. pneumophila PatA additionally shows Phosphatidylglycerole-specific phospholipase A activity. Serin-72, which is embedded in an G-X-S-X-G lipase motiv is essential for the lipolytic activity of PatA. PatA locates to, or close to, the cytoplasmic membrane when expressed in A549 epithelial cells. The lipolytic activity of PatA is not required for membrane targeting and deletion of a C-terminal region abolishes proper targeting. Virulence attenuated L. pneumophila mutants, develop an easy recognizable phenotype during co-culture with A. castellanii on agar plates that was named „scatterphenotype“. On the basis of the scatterphenotype, a new assay was developed allowing screening of huge clone banks with respect to amoebae sensitivity, a marker for reduced virulence. Here, a collection of several thousand transposon mutagenized L. pneumophila clones was screened and a total of 119 amoebae sensitive mutants was isolated. Among those, 70 novel putative host cell colonization and virulence genes were identified including two members of the patatin-like protein family (patD, PatF). patD is cotranscribed with bdhA, therefore forming an operon. bdhA encodes a putative 3-hydroxybutyrate dehydrogenase. The operon is involved in the poly-beta-hydroxybutyrate (PHB) metabolism of L. pneumophila and is needed for replication in host cells. The study provides the first experimentally funded data showing the linkage of PHB metabolism and virulence of L. pneumophila.
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Schulz, Tino. "Untersuchungen zur Virulenzassoziation des Flagellenregulons von Legionella pneumophila." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16599.
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Im Fokus dieser Arbeit stand die Analyse von Faktoren, die den Zusammenbau des Flagellenapparates von Legionella pneumophila (Lp) regulieren. Mit einem kombinierten Replikations-/ Überlebensversuchs mit Lp Corby oder Lp Paris und ihren zugehörigen Regulationsmutanten wurde eine verminderte Fitness für dfliA und erstmals für drpoN, dfleQ defiziente Stämme nachgewiesen. Zur Validierung von Microarray-Daten aus Lp Paris wurden wachstumsphasenabhängige Transkriptions- und Translationsanalysen mit Lp Corby Wildtyp und drpoN, dfleQ, dfliA und dflaA defizienten Stämmen durchgeführt. Es wurde gezeigt, dass die basale Expression von fliA in den späteren Phasen unabhängig von RpoN und FleQ stattfindet. In dieser Arbeit konnte erstmals der Transkriptionsstartpunkt des Hauptregulators FliA bestimmt werden. Es zeigte sich eine putative RpoD (S70) Bindungsstelle. Ein Modell zur Regulation der fliA Expression wurde weiterentwickelt. Demnach kommt es in der exponentiellen Phase durch das Zusammenwirken von RpoD und DksA, aber unabhängig von FleQ, zur basalen fliA Promotoraktivität. Durch den Übergang in die transmissive Phase und direkte oder indirekte Interaktion mit FleQ sowie dem Alarmon ppGpp scheint es zu einem Austausch des Sigmafaktors S70 gegen SS und zu einer Aktivierung der fliA Expression zu kommen. Elektronenmikroskopische Studien zeigten, dass drpoN und dfleQ defiziente Mutanten wahrscheinlich aufgrund des fehlenden Basalkörpers nicht flagelliert sind. Mutanten für dfliA, dflaA und dfliD hatten ebenfalls keine Flagelle, zeigten aber eine ungewöhnliche, gerade Hook Struktur, die den Zusammenbau des Basalkörpers demonstriert. Weiterhin wurden durch in silico Studien 15 Legionella Spezies in Bezug auf das Flagellensystem und ein putatives Chemotaxissystem untersucht. So konnte L. oakridgensis als erste Art ohne beide Systeme sequenziert werden. Andererseits konnten mit LLAP12, L. bozemanii, L. gormanii und L. lytica Stämme beschrieben werden, die beide Systeme tragen.This work focused on the analysis of factors contributing to the regulation of the flagellum self-assembly of Legionella pneumophila (Lp). With a combined replication/survival assay with Lp Corby or Lp Paris and their corresponding regulatory mutants a reduced fitness could be verified for dfliA and for the first time for drpoN, dfleQ deficient strains. For validation of microarray-data for Lp Paris with strain Lp Corby a growth phase dependent analysis of transcription and translation rates was done with wild-type and the drpoN, dfleQ, dfliA and dflaA deficient strains. A regulation of basal fliA expression independently from RpoN and FleQ was shown in the later growth phases. Furthermore the transcriptional start site of fliA could be shown for the first time. A RpoD (S70) binding site could be identified. According to a further developed model for the regulation of the fliA expression RpoD and DksA lead to a basal fliA promotor activity, independently from FleQ. Most likely, during transition to stationary phase, direct or indirect interaction with FleQ and the alarmone ppGpp results in the exchange of the sigma factor S70 and the binding of RpoS. This leads to the activation of fliA expression. Electron microscopic studies revealed that drpoN and dfleQ deficient mutants are not flagellated caused by the missing basal body. Mutants of dfliA, dflaA and dfliD were also aflagellated, but there was a uncommon straight hook structure visible which demonstrates a filament-independent assembly of the basal body. Furthermore, in silico analysis was done with 15 Legionella species with regard to the flagellum regulation system and a putative chemotaxis system. Analysis revealed that the strain L. oakridgensis is the first strain lacking both systems. On the other hand the strains LLAP12, L. bozemanii, L. gormanii and L. lytica could be characterized as strains carrying both systems.
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So, Ernest. "Elucidating Legionella pneumophila effector function using proteomic approaches." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/56986.
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Legionella pneumophila is the causative agent of Legionnaires’ disease, a severe and potentially fatal pneumonia. This intracellular pathogen proliferates by creating a replicative niche, the Legionella containing vacuole (LCV), inside the host and subverting host signalling pathways. Critical to L. pneumophila’s virulence strategy is its defect in organelle trafficking/intracellular multiplication (Dot/Icm) type IVB secretion system. Using the Dot/Icm, L. pneumophila translocates over 300 effector proteins into the host cell to manipulate signalling pathways. The novel effector LtpG localises to the nucleus upon Dot/Icm-dependent translocation. Genomic deletion of ltpG did not exhibit a L. pneumophila intracellular growth defect in all infection models tested. Although LtpG expression did not cause toxicity in mammalian cells, its filamentation induced by cAMP (Fic) domain caused cytotoxicity in yeast and has auto-AMPylation activity. However, small molecule substrate binding assays suggest a guanosine-containing metabolite is preferred. Determination of LtpG host targets using in vitro protein-protein interaction assays did not yield satisfactory results and consequently a more physiologically relevant infection-based mass spectrometric method was developed. Using the biotin ligase BirA, tagged-effectors were biotinylated in a translocation dependent manner. Effector-host protein complexes formed during infection were subsequently isolated and their composition deciphered using quantitative mass spectrometry. The method was downscaled by over 100-fold from the proof-of-concept study and critical parameters such as number of purifications, lysis conditions and crosslinker reactivity tested. This revealed the infection dependent Rab GTPase binding profiles of the promiscuous Rab binding effectors SidM and LidA. Additionally, HSP90, EEF2 and NACA were identified as high confidence physiological binding partners of LtpG, suggesting a role in manipulation of host translation and autophagic pathways as part of L. pneumophila’s virulence strategy.
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Neves, Cândida Maria C. Carvalho. "Pneumonia por Legionella pneumophila : estudo de 10 casos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 1989. http://hdl.handle.net/10183/171779.
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No presente trabalho faz-se uma revisão da literatura sobre pneumonia por Legionella pneumophila e se comparam estes dados com a série da autora, que se compõe de 10 casos esporádicos desta pneumonia, adquiridos na comunidade, ocorridos no perÍodo entre outubro de 1983 e maio de 1989. Todos os pacientes desta série eram do sexo masculino e de cor branca, com idade variando entre 36 e 71 anos. Os sintomas mais freqüentes foram febre alta, calafrios, cefaléia, tosse seca e mialgias. A hipótese diagnóstica baseou-se nos dados clínicos, radiológicos e laboratoriais. Em todos os casos o critério de comprovaçao diagnóstica foi a imunofluorescência indireta para Legionella. Salienta-se a importância do reconhecimento desta doença, que ainda apresenta um baixo Índice de suspeição em nosso meio. Procura-se tanto ressaltar os principais achados clínicos e radiológicos como também contribuir com orientações diagnósticas e terapêuticas. ApÓs a análise dos dados obtidos no trabalho, a autora concluiu que: 1. Os achados da série nao diferem daqueles descritos na literatura. 2. A casuística é restrita para o traçado de um perfil da doença no Rio Grande do Sul. 3. Quadros pneumônicos com má resposta clÍnica à penicilina ou derivados, associados a lesões radiolÓgicas com rápida mutabilidade, devem chamar a atenção para este diagnóstico. 4. A infreqüência deste diagnóstico em nosso meio deve-se ao baixo Índice de suspeição. Logo, a divulgação de informações sobre a doença pode resultar em substancial acréscimo ao registro de casos.In the present work a review is made on the 1iterature about pneumonia by Legione11a pneumophi1a and the data are compared with the series presenteà by the author, composed of 10 sporadic cases of this pneumonia, acquired in the community, October, 1983 and May, 1989. between A11 the patients of this group were ma1e, caucasian, age varying from 36 to 71. The most frequent symptoms were high fever, chills, headache, dry cough and myalgia. The diagnostic hypothesis was baseà on laboratory, radiological and clinicai data. For all the cases, the criterion for diagnostic comprovation was indirect immunofluorescence for Legionella. The importance of the recognition of this disease s emphasized for it still shows a very low 1evel of suspicion in Rio Grande do Sul. The author looks for to ernphazise the main clinicai and radiological findings as well as contributes with diagnostics and therapeutical orientations. After the analysis of the data obtained in the present work the author concludes that: 1. The findings of this series does no differ from those described in the 1iterature. 2. The casuistic is too restricted to draw a profile of the disease in Rio Grande do Sul. 3. Pneumonias with bad clinicai response to penicillin or its derivatives, associated with radiologic lesions with rapid mutability shall call the attention for this diagnosis. 4. The low frequency of this diagnosis in our country is due to the low index of suspicion. Thus, the divulgation of information about the disease could result in substantial increase in the record of new cases.
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Riffard, Serge. "Détection, identification, épidémiologie des Legionella par amplification génique." Lyon 1, 1997. http://www.theses.fr/1997LYO1T285.
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Chang, Po-hsun. "Attachment of Legionella pneumophila to cells in vitro." Thesis, North Texas State University, 1986. https://digital.library.unt.edu/ark:/67531/metadc798334/.
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The attachment and/or penetration of animal cells by two strains of Legionella pneumophila was studied in three vertebrae cell lines in vitro . The study focused on (1) differences in attachment and penetration between the two bacterial strains (an environmental isolate, Johannesburg-2, and a clinical isolate, Chicago-8) and between the cell lines (Hep-2, WI-38 and a murine line); (2) effects of L. pneumophila on cell morphology and growth; and (3) the effects of pyruvate and six sugars or sugar derivatives (D-mannose, D-Galactose, D-Glucose, L-glucose, D-fructose, and 2-deoxy-D-glucose).
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Barker, John E. "The resistance of intra-amoebal grown legionella pneumophila." Thesis, Aston University, 1993. http://publications.aston.ac.uk/12608/.
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Survival studies were conducted on Legionella pneumophila cells that had been grown intracellulary in Acanthamoeba polyphaga and then exposed to polyhexamethylene biguanide (PHMB), benzisothiazolone (BIT), 5-chloro-N-methylisothiazolone (CMIT) and tetradecyltrimethyl ammonium bromide (TTAB). Susceptibilities were also determined for L.pneumophila grown under nutrient sufficient and iron-, nitrogen- and phosphate-depleted conditions, in a chemically defined medium. BIT was relatively ineffective against cells grown under iron-depletion; in contrast iron-depleted conditions increased the susceptibilities of cells to PHMB, TTAB and CMIT. Cells grown under phosphate-depletion showed a marked increase in sensitivity towards all the biocides. Conversely, the activities of all four biocides were greatly reduced against L.pneumophila grown in amoebae. To study the physiological basis for the increased resistance of intra-amoebal grown legionella, the surface properties of the cells were examined by studying outer membrane proteins (OMs), lipopolysaccharides and cellular fatty acids. Intra-amoebal grown legionella were found to differ in several respects compared to cells grown in vitro; they contained a novel 15-kDal OM protein and a monosaturated straight-chain fatty acid (18:19). These compounds were also found in abundant quantities in the host amoeba. Intra-amoebal grown legionella contained more LPS bands than did in vitro grown organisms and were less susceptible to protease K digestion. Cells grown under phosphate depletion were markedly sensitive to protease K digestion and contained lower levels of LPS. Immunoblot analysis of intra-amoebal grown legionella with anti-acanthamoebal serum revealed that both the surface of the bacteria and sarkosyl extracted OMs contained amoebal proteins. These findings suggest that the 15-kDal OM protein is likely to be of amoebal origin and binds tightly to the OM of the bacterium. It is proposed that disruption of amoebal membranes, as a result of intra-amoebal infection liberates macromolecules, including a 15-kDal polypeptide, a major constituent of the membrane, which associates closely with the surface of the legionellae. Thus L.pneumophila which have extraneous membrane material bound to their surface may respond differently to biocide inactivation, as these macromolecules may act as a penetration barrier to such agents. This phenomenon could contribute to the recalcitrance of legionellae in water systems.
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Jakubek, Delphine. "Ecologie des légionelles dans l’eau des circuits de refroidissement des centrales nucléaires en bord de Loire." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112414.
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Les circuits de refroidissement des centrales nucléaires en bord de rivière sélectionnent par leur mode de fonctionnement des micro-organismes à caractère thermophile, parmi lesquels le micro-organisme pathogène, Legionella pneumophila. Pour lutter contre le développement de ce genre bactérien, un traitement de désinfection de l’eau des circuits de refroidissement à la monochloramine peut être employé. Pour participer à la maitrise des risques sanitaires et environnementaux liés à la modification physico-chimique et microbiologique de l’eau naturelle prélevée, EDF s’est engagé dans une démarche d’amélioration des connaissances sur l’écologie de Legionella pneumophila dans les circuits de refroidissement et des liens que cette espèce bactérienne entretient avec son environnement (physico-chimique et microbiologique) favorisant ou non sa prolifération. Ainsi, la diversité et la dynamique des Legionella pneumophila cultivables ont été déterminées dans les quatre centrales nucléaires en bord de Loire pendant un an et leurs liens avec leur environnement physico-chimique et microbiologique ont été étudiés. Cette étude a mis en évidence une forte diversité des sous-populations de Legionella pneumophila et une apparente dynamique qui semble être liée à l’évolution d’un nombre restreint de sous-populations. Les sous-populations de Legionella pneumophila semblent entretenir des relations souche-spécifiques avec les paramètres biotiques et présenter des sensibilités différentes aux variations physico-chimiques du milieu. La conception des circuits de refroidissement pourrait impacter la communauté de légionelles. L’utilisation de la monochloramine perturbe fortement l’écosystème mais ne sélectionne pas de populations tolérantes au biocideThe cooling circuits of nuclear power plants, by their mode of operating, can select thermophilic microorganisms including the pathogenic organism Legionella pneumophila. To control the development of this species, a disinfection treatment of water cooling systems with monochloramine can be used. To participate in the management of health and environmental risks associated with the physico-chemical and microbiological modification of water collected from the river, EDF is committed to a process of increasing knowledge about the ecology of Legionella pneumophila in cooling circuits and its links with its environment (physical, chemical and microbiological) supporting or not their proliferation. Thus, diversity and dynamics of culturable Legionella pneumophila were determined in the four nuclear power plants along the Loire for a year and their links with physico-chemical and microbiological parameters were studied. This study revealed a high diversity of Legionella pneumophila subpopulations and their dynamic seems to be related to the evolution of a small number of subpopulations. Legionella subpopulations seem to maintain strain-specific relationships with biotic parameters and present different sensitivities to physico-chemical variations. The design of cooling circuits could impact the Legionella pneumophila community. The use of monochloramine severely disrupts the ecosystem but does not select biocide tolerant subpopulations
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Ahanotu, Ejemihu Ndu. "Immune Response of the Rat to Outer Membrane Proteins of Legionella pneumophila." Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc935780/.
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Outer membrane proteins (OMPs) were recovered from eleven strains (eight serogroups) of Legionella pneumophila by sequential treatment with Tris buffer (pH 8), citrate buffer(pH 2.75) and Tris buffer (pH 8). Transmission electron microscopy revealed clearly the separation of the outer membrane from the bacteria. The development of delayed hypersensitivity was also noted by measuring the area of arythema and induration produced by intradermal injections of the MPSs from Chicago 8 strain. The adjuvants enhanced greatly both active and cell-meditated immunity (CMI). Transient lymphocytopenia with a slight rise in neutrophils was noted in each of the immunized groups. Intraperitoneal challenge, seven days after the OMP booster, of one LD (1.5 x10^6) of legionellae resulted in lymphocytopenia with elevated neutrophils. All immunized rats survived the challenge, although those in the saline-OMP group were clearly the sickest. Post-challenge, legionella antibody titers rose greatly and CMI was heightened. Passive immunization (homologous and heterologous) was found to protect the rats from a challenge of on LD. Actively-immunized rats retained their immunity for at least six months as determined by their resistance to a second challenge.
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Strickhouser, Amanda. "Legionella pneumophila in Domestic Hot Water Systems: Evaluation of Detection Methods and Environmental Factors Affecting Survival." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/36046.
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Legionella is the causative agent of Legionnairesâ disease which hospitalizes 8,000 to 18,000 people in the United States each year. The disease in transmitted through inhalation or aspiration of water containing the bacterium and can be acquired within the home. Studies have found that 0-37% of domestic water heaters contain Legionella, making household hot water systems a potential route of exposure.
The objective of this research was to evaluate different methods for testing environmental samples for Legionella pneumophila and to analyze potable water conditions that affect survival of free living Legionella pneumophila in hot water tanks. Three heat pretreatment methods (50ºC for 30 minutes, 55ºC for 15 minutes, and 60ºC for 3 minutes) were not effective at recovering Legionella in this study. There was no statistically significant difference between the three acid pretreatment methods that were tested (pH 2.0 with a neutralizing solution, pH 2.2, and the CDC method). Six media (BCYE, DGVP, PCV, GPCV, CCVC, and GPVA) exhibited similar Legionella recovery, except for when high levels of non-Legionella organisms were present, in which case BCYE demonstrated lower recovery. When disinfectant was present, if sodium thiosulfate was not added before the disinfectant, Legionella recovery was lower. However, this result was not statistically significant for free chlorine until after 5 minutes. Pseudomonas aeruginosa (up to 67.5 cfu/ml) and pyocyanin (up to 9 mg/l) did not have an effect on Legionella recovery under the tested conditions.
Environmental factors affecting survival of free living Legionella pneumophila in hot water tanks were also studied. After one day exposure in small-scale simulated water heaters at 55ºC, viable Legionella could not be recovered. At 44ºC, Legionellae were recovered after one day but only at very low levels after eight days. Between 23 and 37ºC, Legionella could survive longer than eight days. Copper (Cu2+) concentrations above 2160 ppb were found to be toxic to Legionella, but iron (Fe3+) between 1 and 2160 ppb did not affect survival. Above pH 11 survival was greatly reduced. No effect was observed between pH 5-10. When glass fiber filters were added to the reactors and they were seeded with tap water and sediment slurry, Legionellae were retained in 7 of 16 reactors for 327 days.
The results of this work will assist in optimal identification of Legionella via microbial analysis of potable water samples, thereby assisting in prevention and diagnosis of factors contributing to Legionnairesâ disease, especially in settings with high-risk patients (e.g. hospitals). Water systems studying Legionella amplification in domestic hot water systems can use simulated or real distribution system sampling to reproduce and study factors that prevent or reduce Legionella growth and persistence.Master of Science
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Brunel, Romain. "Trans-traduction chez la bactérie pathogène de l’homme Legionella pneumophila." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1219/document.
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L'objectif global de ma thèse a été d'étudier un mécanisme cellulaire qui intervient dans la traduction des protéines : la trans-traduction. Nous avons étudié le rôle de ce mécanisme chez notre modèle d'étude, la bactérie pathogène de l'homme Legionella pneumophila, l'agent étiologique de la Légionellose. Ce travail a été réalisé sous forme de deux axes majeurs. D'abord, nous avons démontré l'essentialité de ce mécanisme pour la viabilité de cette bactérie et pour sa capacité à se multiplier intracellulairement dans des cellules eucaryotes. Puis nous avons évalué l'efficacité d'un nouvel antibiotique décrit comme étant un inhibiteur de la trans-traduction, pour le traitement de la Légionellose. Ces deux axes ont été complétés par un troisième axe qui visait la mise en place de la technique de Tn-seq chez L. pneumophila et l'archée Pyrococcus furiosus. Cet axe a permis l'ouverture de mes travaux à la recherche d'autres mécanismes essentiels dont nous ignorons le potentiel comme cible antibiotique, et à l'étude des mécanismes de transfert de gène horizontauxThe global objective of my thesis work was the study of a cellular mechanism involved in protein translation: trans-translation. We studied the role of that mechanism in a model organism, the human bacterial pathogen Legionella pneumophila that causes Legionnaire's disease. This work was performed under two principal axes. First, we demonstrated the essentiality of this mechanism for the growth in vitro and the intracellular multiplication of this bacterium in eukaryotic cells. Then, we assessed the efficiency of a new antibiotic compound described as an inhibitor of trans-translation against the etiologic agents of Legionnaire's disease. These two axes were then completed by a third axis, which aimed at implementing the Tn-seq technique in L. pneumophila and the archaea Pyrococcus furiosus. This approach allowed to open my work to the reseach of other essential mechanisms that could be used as antibiotic targets, and to the study of a mechanism of horizontal gene transfer
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Diez, Eduardo. "Positional cloning of the Legionella pneumophila-resistance gene Lgn1." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85151.
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Legionella pneumophila is an intracellular bacterium that causes an acute form of pneumonia called Legionnaires' disease. Segregation analyses using macrophages from susceptible and resistant inbred mice previously indicated that a single genetic locus, named Lgn1 , could determine permissiveness to intracellular replication of L. pneumophila. A positional cloning strategy was undertaken, which makes use of genetic and molecular biology techniques to identify the gene responsible for a particular phenotype, based mostly on its location within a chromosome. The work described in this thesis covers three aspects of Lgn1: (1) Building upon the work of others, the Lgn1 genetic interval was narrowed to 0.32 cM within distal mouse chromosome 13. The corresponding 140 Kb Lgn1 physical interval contains only two known transcripts: the Neuronal Apoptosis Inhibitor Protein ( Naip) genes Naip2 and Naip5. (2) The expression profile of the Lgn1 candidates was investigated both at the mRNA and protein levels. Expression of both Naip2 and Naip5 in mouse macrophages strengthened their candidacy for the Lgn1 locus. (3) Transfer of BAC clones from the critical interval into transgenic mice was successfully used to functionally complement the Lgn1 susceptibility phenotype of A/J mice with cloned DNA from non-permissive 129X1 or C57BL/6J origins. Two independent rescuing BAC clones were identified, with a 56-Kb overlap where the entire Lgn1 transcript must lie. The only known full-length transcript coded in this reduced genomic region is Naip5.Thus, in our last publication we have proposed that Naip5 (recently named Birc1e) is the gene within the Lgn1 locus responsible for differential permissiveness to intracellular L. pneumophila replication in mice.
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Joller, Nicole Christine. "Humoral immune response to the intracellular pathogen Legionella pneumophila /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17950.
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Scheiding, Victoria Madeleine [Verfasser]. "Immune defense mechanisms against Legionella longbeachae / Victoria Madeleine Scheiding." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1206417552/34.
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Schell, Ursula. "Biochemical analysis of phosphorylation signalling through the Legionella pneumophila." Diss., Ludwig-Maximilians-Universität München, 2015. http://nbn-resolving.de/urn:nbn:de:bvb:19-183854.
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Troxell, Stephen B. "Legionella pneumophila occurrence in waters of east central Indiana." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1319834.
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Drinking water is a potential means for transmission of the opportunistic pathogen Legionella pneumophila. The objective of this research was to document the occurrence of L. pneumophila from source water, partially treated water after conventional water treatment, and distribution water. Water samples were examined for L. pneumophila by direct fluorescent antibody (DFA) techniques and by SYBR Green based real-time multiplex PCR. Primers were designed to amplify a 16S product of 490 bp and a mip product of 290 bp within L. pneumophila. Sensitivity of culture methods and PCR was determined by percent recovery and by using serial dilutions of positive control DNA, respectively. Eighty percent of source water samples were positive for L. pneumophila by real-time PCR versus 100% positive by DFA for L. pneumophila. Twenty percent of GAC filter water samples were positive for L. pneumophila by real-time PCR versus 40% positive by DFA. Distribution water samples yielded mixed results. Twenty percent of biofilms from the distribution system were positive for L. pneumophila by real-time PCR. This project confirms the potential for human infection by L. pneumophila from distribution water within the study area.Department of Biology
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Herrmann, Vroni. "Die Funktion von Glukose im Lebenszyklus von Legionella pneumophila." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16462.
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Legionella pneumophila ist ein Gram-negatives, ubiqitär verbreitetes Proteobakterium, das als Auslöser der Legionärskrankheit gilt. Die Ergebnisse dieser Arbeit bestätigen, dass Serin eine wichtige Kohlenstoffquelle für Aminosäuren darstellt und dass L. pneumophila für die Aminosäuren Isoleucin, Leucin, Phenylalanin, Tyrosin, Histidin, Prolin und Valin auxotroph ist. Innerhalb der Replikationsvakuole greift L. pneumophila auf Aminosäuren des Wirts zurück und inkorporiert diese in Proteine. Die untersuchte Spezies besitzt die Fähigkeit zur de novo-Biosynthese von Serin. Die vorliegende Arbeit zeigt zudem erstmals, dass Glukose für die Biosynthese von Aminosäuren sowie Polyhydroxybutyrat (PHB) verwendet wird. Der Entner-Doudoroff-Weg (EDW) kann als Haupt-Katabolismusroute von Glukose identifiziert werden. Ein Deletionsstamm des EDW zeigt gegenüber dem Wildtypstamm in nährstoffarmer Umgebung deutlich verminderte Fitness nach erfolgreicher Replikation innerhalb A. castellanii. Die Glukoamylase GamA wird in dieser Arbeit erstmals als verantwortliches Enzym für die Stärke- und Glykogenhydrolyse von L. pneumophila charakterisiert. Der putative Transkriptionsaktivator YozG bindet sowohl im 5’-DNA-Bereich von gamA als auch im eigenen putativen Promotorbereich und reguliert die Hydrolyseaktivität von GamA. Es werden zudem Argumente für die Hypothese erbracht, dass YozG auch als cis-aktives Element fungiert. Die Biosynthese von Polyhydroxybutyrat (PHB) aus Glukose findet während des spät-exponentiellen Wachstums statt und steigert sich in der stationären Phase. Eine verminderte PHB-Menge im EDW-Deletionsstamm wird als Erklärung für die verminderte Fitness in nährstoffarmer Umgebung diskutiert. Die Ergebnisse dieser Arbeit zeigen, dass L. pneumophila neben Aminosäuren auch Glukose sowie die natürlich vorkommenden Glukosepolymere Glykogen und Stärke als Kohlenstoffquellen zur Biosynthese von Aminosäuren und PHB nutzt und dass diese Synthese zur Fitness der Spezies beiträgt.Legionella pneumophila is a Gram-negative proteobacterium causing Legionnaires’ disease. The results of this study confirm that serine is a carbon source for amino acids and that L. pneumophila is auxotrophic for the amino acids isoleucine, leucine, phenylalanine, tyrosine, histidine, proline, and valine. L. pneumophila uses amino acids of the host cells to incorporate them into proteins. Serine is synthesized de novo. Furthermore, this work demonstrates for the first time that glucose is used for the biosynthesis of amino acids and polyhydroxybutyrate (PHB). The Entner-Doudoroff pathway is identified as the predominant pathway for the catabolism of glucose. In a nutrient-depleted environment, after replication has taken place in A. castellanii, a deletion strain of the Entner-Doudoroff pathway exhibits strongly reduced fitness as compared to the wildtype. The glucoamylase GamA is characterized as the enzyme responsible for the starch and glycogen degrading activity of L. pneumophila for the first time. The putative transcription activator YozG binds to the 5’ region of gamA as well as to his own putative promoter region and regulates GamA activity. Furthermore, arguments are provided to support the hypothesis that YozG also acts as a cis-active element. The biosynthesis of polyhydroxybutyrate (PHB) from glucose starts in the late exponential phase and increases in the stationary growth phase. As an explanation for reduced fitness of the Entner-Doudoroff deletion strain in nutrient-depleted environment, a reduced amount of PHB is proposed. The results of this work prove that L. pneumophila uses not only amino acids but also glucose and the natural glucose polymers starch and glycogen as carbon sources for the biosynthesis of amino acids and PHB and that thereby the fitness of the species is increased.