title: Chlamydiae as symbionts in eukaryotes.
abstract: Members of the phylum Chlamydiae are obligate intracellular bacteria that were discovered about a century ago. Although Chlamydiae are major pathogens of humans and animals, they were long recognized only as a phylogenetically well-separated, small group of closely related microorganisms. The diversity of chlamydiae, their host range, and their occurrence in the environment had been largely underestimated. Today, several chlamydia-like bacteria have been described as symbionts of free-living amoebae and other eukaryotic hosts. Some of these environmental chlamydiae might also be of medical relevance for humans. Their analysis has contributed to a broader understanding of chlamydial biology and to novel insights into the evolution of these unique microorganisms.
authors.affiliation: Department of Microbial Ecology, University of Vienna, A-1090 Vienna, Austria. horn@microbial-ecology.net
authors.forename: Matthias
authors.initials: M
authors.lastname: Horn
mesh_terms: D000656:Amoeba / Q000382:microbiology; D000818:Animals; D005075:Biological Evolution; D002695:Chlamydiales / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity / Q000502:physiology*; D017753:Ecosystem; D005057:Eukaryotic Cells / Q000382:microbiology*; D006801:Humans; D010944:Plants / Q000235:genetics / Q000382:microbiology; D011634:Public Health; D013559:Symbiosis