Affiliation:
1. Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
2. Institut Pasteur, Université de Paris, Unité Biologie des Bactéries Intracellulaires, Paris, France
Abstract
SUMMARY
Legionella pneumophila
is a Gram-negative environmental bacterium, which survives in planktonic form, colonizes biofilms, and infects protozoa. Upon inhalation of
Legionella
-contaminated aerosols, the opportunistic pathogen replicates within and destroys alveolar macrophages, thereby causing a severe pneumonia termed Legionnaires’ disease. Gram-negative bacteria employ low molecular weight organic compounds as well as the inorganic gas nitric oxide (NO) for cell-cell communication.
L. pneumophila
produces, secretes, and detects the α-hydroxyketone compound
Legionella
autoinducer-1 (LAI-1, 3-hydroxypentadecane-4-one). LAI-1 is secreted by
L. pneumophila
in outer membrane vesicles and not only promotes communication among bacteria but also triggers responses from eukaryotic cells.
L. pneumophila
detects NO through three different receptors, and signaling through the volatile molecule translates into fluctuations of the intracellular second messenger cyclic-di-guanylate monophosphate. The LAI-1 and NO signaling pathways are linked
via
the pleiotropic transcription factor LvbR. In this review, we summarize current knowledge about inter-bacterial and inter-kingdom signaling through LAI-1 and NO by
Legionella
species.
Funder
Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung
Agence Nationale de la Recherche
Fondation pour la Recherche Medicale
Publisher
American Society for Microbiology