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78 • "PROTIST—2016
the transfer of genes from the endosymbiont to host (EGT), the presence of such genes indicates past endosymbiosis. To test the plastid-early hypothesis and to learn more about the contribution of EGT to euglenid genome, we have analyzed transcriptomes of 5 euglenids (2 osmotrophic, 3 autotrophic) using a pipeline, which enabled us to select genes related to algae. The contribution of algal genes in autotrophic euglenids (around 2 % of genes) is higher than in primary osmotrophs (around 0.07 %) supporting the plastid-late hypothesis. Surprisingly, we observed a high number of genes related to other algal groups than green algae.
CHARACTERIZATION OF A NOVEL PARAMECIUM ENDOSYMBIONT AND A CRITICAL REVISION OF "BASAL RICKETTSIALES" Szokoli F.12, Schrallhammer M.3, Sabaneyeva E.4, Castelli M.2, Krenek S.1, Doak T.G.56, Verni F.2, Berendonk T.U.1, Petroni G.2
1 - Institut für Hydrobiologie, Technische Universität Dresden, Germany
2 - Dipartimento di Biologia, Université di Pisa, Italy
3 - Mikrobiologie, Institut für Biologie II, Albert-Ludwigs-UniversitätFreiburg, Germany
4 - Department of Cytology and Histology, St. Petersburg State University, Russia
5 - Biology, Indiana University, IN, USA
6 - National Center for Genome Analysis Support, IN, USA
[email protected] In the past ten years, the number of newly described endosymbionts within the bacterial order Rickettsiales has constantly grown, and 18 novel Rickettsiales genera inhabiting protists—such as ciliates or amoeba—have been described since 2006. Half of these new species belong to the recently proposed family " Candidatus Midichloriaceae", whereas five novel bacterial symbionts were found belonging to Rickettsiaceae and six belonging to Holosporaceae and other Rickettsiales with uncertain position ("basal Rickettsiales"). In this work, we provide molecular and ultrastructural data on a novel bacterial endosymbiont inhabiting a Paramecium biaurelia isolate collected near Bloomington, Indiana (USA). We propose the name " Candidatus Jurandia parameciophila" in honor of Dr. Artur Jurand. The Gram-negative bacteria (1.5-2.0 * 0.35-0.38 ^m in size) occupies the host cytoplasm and is devoid of flagella. For molecular characterization, the SSU rRNA gene was sequenced and used for taxonomic assignment and the design of species-specific oligonuc-leotide probes. Phylogenetic analyses indicate that the endosymbiont belongs to "basal Ricket-
tsiales" (Alphaproteobacteria), clustering with the recently proposed family " Candidatus Paracaedi-bacteraceae". We obtained tree topologies showing a strong separation of Rickettsiales into at least two groups; one represented by the families Rickettsiaceae, Anaplasmataceae, and "Candidatus Midichloriaceae", the so-called RAM clade, and the other group represented by "basal Rickettsiales" including " Candidatus Jurandia parameciophila". Therefore, and in accordance with other recent publications, we propose to limit the order Rickettsiales to the RAM clade and rise "basal Rickettsiales" to an independent order, Holosporales ord. nov., inside Alphaproteobacteria, presently comprising four clades at the family level.
'ANAERAMOEBA' - NEW LINEAGE WITHIN METAMONADA
Taborskv P.1, Panek T.12, Kolisko M.3, Cepicka I.1
1 - Department of Zoology, Charles University in Prague, Prague, Czech Republic
2 - Department of Biology and Ecology Faculty of Science University ofOstrava Chittussiho 10, Ostrava, 710 00
3 - Department of Botany, University of British Columbia, Vancouver, British Columbia, Canada [email protected]
We have isolated and cultured nine strains of anaerobic amoebae ('Anaeramoeba') from marine coastal hypoxic sediments worldwide. 'Anaeramoeba' cells were fan-shaped, with extremely flattened pseudopodia and trailing uroidal filaments, and morphologically belonging to flamellian or flabellate morphotype. We distinguished six morphospecies that differed in a number of features including cell size and nuclear morphology. ' Anaer-amoeba' species shared a unique combination of morphological features. All three strains examined by TEM possessed double membrane-bound organelles with no cristae, presumably hydrogenosomes, associated with prokaryotes (probably methanogens). Cytoplasm contained a large acentriolar centrosome, and no basal bodies were observed. Peculiar isokont flagellates with two or four flagella were rarely observed in two strains representing different species. Single- and also five-gene analyses showed that 'Anaeramoeba' clade was monophyletic, but were completely unable to assess its phylogenetic position. We analysed transcriptomic data of two 'Anaeramoeba'species. Phylogenomic analysis based on 160 protein-coding genes surprisingly showed that 'Anaeramoeba' instead ofbeing a member ofAmoebozoa, represents a novel deep lineage within Metamonada (Eukaryota: Excavata).
