Klaus Heuner

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Legionella pneumophila, the etiologic agent of Legionnaires' disease, contains a single, monopolar flagellum which is composed of one major subunit, the FlaA protein. To evaluate the role of the flagellum in the pathogenesis and ecology of Legionella, the flaA gene of L. pneumophila Corby was mutagenized by introduction of a kanamycin resistance cassette.(More)
Horizontal gene transfer probably contributes to evolution of Legionella pneumophila and its adaptation to different environments. Although horizontal gene transfer was observed in Legionella, the mechanism is still not specified. In this study we identified and analysed a new type of conjugation/type IVA secretion system (trb/tra) of L. pneumophila Corby,(More)
Legionalla pneumophila is a human pathogen causing atypical pneumonia. It is a monopolar flagellated gram-negative bacterium. Flagellation of L. pneumophila is life cycle dependent and the expression of flagella is genetically linked to the virulence phenotype. Non-flagellated mutants of L. pneumophila are less infectious for macrophages and amoebae(More)
Francisella tularensis is a zoonotic agent and the subspecies novicida is proposed to be a water-associated bacterium. The intracellular pathogen F. tularensis causes tularemia in humans and is known for its potential to be used as a biological threat. We analyzed the genome sequence of F. tularensis subsp. novicida U112 in silico for the presence of a(More)
Legionella pneumophila is a Gram-negative freshwater agent which multiplies in specialized nutrient-rich vacuoles of amoebae. When replicating in human alveolar macrophages, Legionella can cause Legionnaires' disease. Recently, we identified a new type of conjugation/type IVA secretion system (T4ASS) in L. pneumophila Corby (named trb-tra). Analogous(More)
Adaptation to the host environment and exploitation of host cell functions are critical to the success of intracellular pathogens. Here, insight to these virulence mechanisms was obtained for the first time from the transcriptional program of the human pathogen Legionella pneumophila during infection of its natural host, Acanthamoeba castellanii. The(More)
The gene flaA, encoding the flagellum subunit protein of Legionella pneumophila serogroup 1, has been isolated from an expression library of L. pneumophila isolate Corby in Escherichia coli K-12 by using an antiflagellin specific polyclonal antiserum. DNA sequence analysis of the flaA gene revealed the presence of a 1,428-bp open reading frame encoding a(More)
The haploid amoeba Dictyostelium discoideum is a versatile host system for studying cellular aspects of Legionella pathogenicity. Previous studies have shown that the internalization of L. pneumophila leads to an endoplasmic reticulum (ER)-derived organelle that supports intracellular replication of the bacteria. In this study a roadmap of host-cell factors(More)
Legionella spp. the causative agent of Legionnaires' disease is naturally found in fresh water where the bacteria parasitize intracellularly within protozoa. Upon aerosol formation via man-made water systems, Legionella can enter the human lung and cause a severe form of pneumonia. Here we review results from systematic comparative genome analysis of(More)