TY  - JOUR
A1  - Hacker, Jörg
A1  - Ott, M.
A1  - Ludwig, B.
A1  - Rdest, U.
T1  - Intracellular survival and expression of virulence determinants of Legionella pneumophila
N2  - Legionella pneumophila, the causative agent of Legionnaires' disease is able to live and multiply within macrophages as weil as within protozoan organisms. Legionella strains inhibit phagosome-lysosome fusion and phagosome acidification. By using two different cell culture systems, one derived from human macrophages and the other from human.embryo lung fibro:blastic cells, it is demonstrated that Legionella strains lose their virulence following cultivation in the laboratory. In order to study the mechanisms involved in intracellular survival of Legionella a genomic library of strain Legionella pneumophila Philadelphia I was established in Escherichia coli K-12. By cosmid cloning technique we were able to clone five putative virulence factors, two of which exhibit hemolytic activities and three of which represent membrane-associated proteins of 19, 26 and 60 kilodalton. One of the hemolytic proteins, termed legiolysin, represents a new toxin which specifically lyses human erythrocytes. The other hemolysin exhibits proteolytic properties in addition and is cytolytic for Vero and CHO cells. Further sturlies will be necessary to determine the exact role of the cloned proteins in the pathogenesis of Legionella. Zusammenfassung: Intrazelluläres Überleben
N2  - Intrazelluläres Überleben und Expression der Virulenzdeterminanten vonLegionella pneumophila. L. pneumophila, der Erreger der Legionärskrankheit, hat die Fähigkeit, sowohl in Makrophagen als auch in Protozoen zu leben und sich dort zu vermehret;t. Legionellen inhibieren die Fusion von Phagosom und Lysosom und hemmen die Ansäuerung des Phagosoms. Mit Hilfe von zwei unterschiedlichen Zellkultur-Systemen konnte gezeigt werden, daß Legionella-Stämme ihre Virulenz nach Laborpassage verlieren. Um die Mechanismen zu studieren, die für das intrazelluläre Überleben von Legionellen verantwortlich sind, haben wir eine Genbank des Legionella pneumophila-Stammes Philadelphia I in Escherichia coli K-12angelegt. Mit Hilfe der Cosmid-Klonierungstechnik war es möglich, fünf putative Virulenzfaktoren zu klonieren. Zwei von diesen Faktoren haben hämolytische Eigenschaften und drei sind Membran-assoziierte Proteine mit Molekulargewichten von 19, 26 und 60 kilodalton. Eines der hämolytischen Proteine, das Legiolysin, lysiert spezifisch humane Erythrozyten. Das zweite Hämolysin zeigt zusätzlich proteolytische Eigenschaften und schädigt sowohl Vero- als auch CHO-Zellen. Weitere Studien sind notwendig, um die Rolle der klonierten Proteine in der Pathogenese von Legionella exakt zu bestimmen.
KW  - Infektionsbiologie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59681
ER  - 
TY  - JOUR
A1  - Bender, L.
A1  - Ott, M.
A1  - Debes, A.
A1  - Rdest, U.
A1  - Heesemann, J.
A1  - Hacker, Jörg
T1  - Distribution, expression and long range mapping of legiolysin gene (lly) specific DNA sequences in Legionellae
N2  - The legiolysin gene (lly) cloned from Legionella pneumophila Philadelphia 1 confers the phenotypes of hemolysis and browning of the culture medium. An internal Uy-specific DNA probe was used in Southern hybridizations for the detection of Uy-specific DNA in the genomes of legioneUae and other gram-negative pathogenic bacteria. Under conditi9ns of high stringency, tlie Uy DNA probe specifically reacted with DNA fragments fr9m L. pneumophiüz isolates; by reducing stringency, hybridization was also observed for all other Legionella strains tested. No hybridization occurred with DNAs isolated from bact~ria of other genera. The Uy genewas mapped by pulsed-field gel electrophoresis to the respective genomic Notl fragments of Legionelltz isolates. By using antilegiolysin monospecific polyclonal antibodies in Western blots (immunoblots), Lly proteins could be detected only in L. pneumophila isolates.
KW  - Infektionsbiologie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59744
ER  - 
TY  - JOUR
A1  - Wintermeyer, E.
A1  - Rdest, U.
A1  - Ludwig, B.
A1  - Debes, A.
A1  - Hacker, Jörg
T1  - Characterization of legiolysin (lly); responsible for hemolytic activity, colour production and fluorescence of Legionella pneumophila
N2  - No abstract available
KW  - Infektionsbiologie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59706
ER  -