title: 16S-23S rRNA gene internal transcribed spacer sequences for analysis of the phylogenetic relationships among species of the genus Porphyromonas.
abstract: The 16S-23S rRNA gene internal transcribed spacer (ITS) regions of 11 reference strains of Porphyromonas species, together with Bacteroides distasonis and Tannerella forsythensis, were analysed to examine interspecies relationships. Compared with the phylogenetic tree generated using 16S rRNA gene sequences, the resolution of the ITS sequence-based tree was higher, but species positioning and clustering were similar with both approaches. The recent separation of Porphyromonas gulae and Porphyromonas gingivalis into distinct species was confirmed by the ITS data. In addition, analysis of the ITS sequences of 24 clinical isolates of Porphyromonas asaccharolytica plus the type strain ATCC 25260(T) divided the sequences into two clusters, of which one was alpha-fucosidase-positive (like the type strain) while the other was alpha-fucosidase-negative. The latter resembled the previously studied unusual extra-oral isolates of 'Porphyromonas endodontalis-like organisms' (PELOs) which could therefore be called 'Porphyromonas asaccharolytica-like organisms' (PALOs), based on the genetic identification. Moreover, the proposal of alpha-fucosidase-negative P. asaccharolytica strains as a new species should also be considered.
authors.affiliation: Lehr- und Forschungsgebiet Orale Mikrobiologie und Immunologie der Klinik für Zahnerhaltung, Parodontologie und Präventive Zahnerhaltung und Institut für Medizinische Mikrobiologie, Universitätsklinikum (RWTH), D-52057 Aachen, Germany.|R. M. Alden Research Laboratory, Santa Monica, CA 90404, USA.
authors.forename: Georg
authors.initials: G
authors.lastname: Conrads
authors.affiliation: R. M. Alden Research Laboratory, Santa Monica, CA 90404, USA.
authors.forename: Diane M
authors.initials: DM
authors.lastname: Citron
authors.affiliation: R. M. Alden Research Laboratory, Santa Monica, CA 90404, USA.
authors.forename: Kerin L
authors.initials: KL
authors.lastname: Tyrrell
authors.affiliation: Lehr- und Forschungsgebiet Orale Mikrobiologie und Immunologie der Klinik für Zahnerhaltung, Parodontologie und Präventive Zahnerhaltung und Institut für Medizinische Mikrobiologie, Universitätsklinikum (RWTH), D-52057 Aachen, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Horz
authors.affiliation: R. M. Alden Research Laboratory, Santa Monica, CA 90404, USA.
authors.forename: Ellie J C
authors.initials: EJC
authors.lastname: Goldstein
mesh_terms: D015373:Bacterial Typing Techniques; D021903:DNA, Ribosomal Spacer / Q000032:analysis*; D020459:Genes, rRNA; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D017861:Porphyromonas / Q000145:classification* / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S