title: 'Candidatus Protochlamydia amoebophila', an endosymbiont of Acanthamoeba spp.
abstract: The obligately intracellular coccoid bacterium UWE25, a symbiont of Acanthamoeba spp., was previously identified as being related to chlamydiae based upon the presence of a chlamydia-like developmental cycle and its 16S rRNA gene sequence. Analysis of its complete genome sequence demonstrated that UWE25 shows many characteristic features of chlamydiae, including dependency on host-derived metabolites, composition of the cell envelope and the ability to thrive as an energy parasite within the cells of its eukaryotic host. Phylogenetic analysis of 44 ribosomal proteins further confirmed the affiliation of UWE25 to the 'Chlamydiae'. Within this phylum, UWE25 could be assigned to the family Parachlamydiaceae based on comparative analyses of the 16S rRNA, 23S rRNA and endoribonuclease P RNA genes. The distinct dissimilarities from its closest relative, Parachlamydia acanthamoebae Bn(9)(T) (7.1, 9.7 and 28.8%, respectively), observed in this analysis justify its classification in a new genus. Therefore, the name 'Candidatus Protochlamydia amoebophila' is proposed for the designation of the Acanthamoeba sp. symbiont UWE25 (=ATCC PRA-7).
authors.affiliation: Department of Microbial Ecology, University of Vienna, 1090 Vienna, Austria.
authors.forename: Astrid
authors.initials: A
authors.lastname: Collingro
authors.affiliation: Department of Microbial Ecology, University of Vienna, 1090 Vienna, Austria.
authors.forename: Elena R
authors.initials: ER
authors.lastname: Toenshoff
authors.affiliation: Department of Microbial Ecology, University of Vienna, 1090 Vienna, Austria.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Taylor
authors.affiliation: The Jones Group/JMI Laboratories, North Liberty, IA, USA.
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Fritsche
authors.affiliation: Department of Microbial Ecology, University of Vienna, 1090 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Wagner
authors.affiliation: Department of Microbial Ecology, University of Vienna, 1090 Vienna, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Horn
mesh_terms: D000048:Acanthamoeba / Q000382:microbiology*; D000818:Animals; D002695:Chlamydiales / Q000145:classification* / Q000235:genetics* / Q000254:growth & development; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D020459:Genes, rRNA; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D043262:Ribonuclease P / Q000235:genetics; D012269:Ribosomal Proteins / Q000235:genetics; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012269:Ribosomal Proteins; D043262:Ribonuclease P