Journal Article

Revised Systematics of Holospora-Like Bacteria and Characterization of \Candidatus Gortzia infectiva\, a Novel Macronuclear Symbiont of Paramecium jenningsi

Schrallhammer, Martina, Boscaro, Vittorio, Petroni, Giulio, Fokin, Sergei I., Schweikert, Michael

2013

Overview

The genus Holospora (Rickettsiales) includes highly infectious nuclear symbionts of the ciliate Paramecium with unique morphology and life cycle. To date, nine species have been described, but a molecular characterization is lacking for most of them. In this study, we have characterized a novel Holospora-like bacterium (HLB) living in the macronuclei of a Paramecium jenningsi population. This bacterium was morphologically and ultrastructurally investigated in detail, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and developed a specific probe for fluorescence in situ hybridization experiments. A new taxon, \"Candidatus Gortzia infectiva\", was established for this HLB according to its unique characteristics and the relatively low DNA sequence similarities shared with other bacteria. The phylogeny of the order Rickettsiales based on 16S rRNA gene sequences has been inferred, adding to the available data the sequence of the novel bacterium and those of two Holospora species (Holospora obtusa and Holospora undulata) characterized for the purpose. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and showed a possible pattern of evolution for some of their features. We suggested to classify inside the family Holosporaceae only HLBs, excluding other more distantly related and phenotypically different Paramecium endosymbionts.

• Publisher: Springer Science + Business Media,Springer-Verlag,Springer,Springer Nature B.V
• Subject: Bacteria / Biological and medical sciences / Biological taxonomies / Biomedical and Life Sciences / Candidatus Gortzia / classification / DNA sequences / DNA sequencing / DNA, Bacterial / DNA, Bacterial - genetics / Ecology / Endosymbionts / Fluorescence / Fluorescence in situ hybridization / Fundamental and applied biological sciences. Psychology / Gene sequencing / genetics / Geoecology/Natural Processes / Holospora / Holospora obtusa / Holospora undulata / Holosporaceae / Holosporaceae - classification / Holosporaceae - genetics / HOST MICROBE INTERACTIONS / Hybridization / In Situ Hybridization, Fluorescence / Infections / Life cycle / Life cycles / Life Sciences / Macronuclei / Macronucleus / Microbial Ecology / Microbiology / Morphology / Nature Conservation / Nucleotide sequence / nucleotide sequences / Paramecium / Paramecium - microbiology / Parasite hosts / Phylogenetics / Phylogeny / ribosomal RNA / Rickettsiales / RNA, Ribosomal, 16S / RNA, Ribosomal, 16S - genetics / rRNA 16S / rRNA genes / Sequence Analysis, DNA / Symbionts / Symbiosis / Systematics / Water Quality/Water Pollution