CC BY
25
28 • "PROTIST—2016
mologues were probably replaced by eukaryotic specific homologue or in the secondarily amito-chondriate groups where it is not necessary anymore. In the other hand, recA genes were subject to further duplication events in green plants, where they present several forms. The reconstruction of the RecA phylogeny with its EGT events retells the very evolutionary history of the euka-ryotes and also bacteria and enables a further understanding of endosymbiosis. We showed a group-wide presence of mitochondrial recA genes in Amoebozoa, Oomycetes, green plants and minor groups giving support to an ancestral EGT acquisition ofmitochondrial recA prior to eukaryotic diversification, as well as chloroplastic recA in all major photosynthesizing groups.
UNVEILING SSU RDNA INTRAGENOMIC POLYMORPHISM IN DEEP-SEA FORAMI-NIFERA USING SINGLE-CELL HIGH THROUGHPUT SEQUENCING Holzmann Maria1, Apothelot-Perret-Gentil Laure1, Voltsky Ivan12, Lejzerowicz Franck1
1 - University of Geneva
2 - Ben Gurion University of the Negev maria.holzmann@unige.ch
The SSU rRNA genes are commonly used for the assessment of protist diversity. It is assumed that the rDNA copies are identical within the individual cells. However, previous studies, using cloning and Sanger sequencing approach showed a high level of intra-individual polymorphism in shallow water benthic foraminifera. Here, we present the results of single cell high-throughput analysis of SSU rDNA in about 200 specimens of abyssal foraminifera. Our data confirm the presence of intragenomic polymorphism in foraminifera but levels of intra-individual divergence are different among taxono-mic groups. Our approach further allows us a quick sorting of foraminifera for barcoding purposes by distinguishing unknown foraminiferal sequences from those that are already present in our database. In the case of unknown sequences the longer SSU fragment is Sanger sequenced afterwards to phylogenetically characterize the putative new species.
ANCIENT MITOCHONDRIAL PROTEIN SECRETION
Horvathova L.1, Zarsky V.1, Derrelle R.2, Krupickova A.1, Klapst'ova V.1, Voleman L.1, Petru M.1, Elias M.3, Panek T.3, Cepicka I.4, Huysmans G.5, Chami M.6, Francetic O.7, Dolezal P.1 1 - Dept. of Parasitology, Charles University in Prague
2 - Dept. de Biologie, Université Paris-Sud 11
3 - Dept. ofBiology and Ecology, University ofOstrava
4 - Dept. of Zoology, Charles University in Prague
5 - Weill Cornell Medical College, Cornell University
6 - Biozentrum der Universität Basel
7 - Institut Pasteur pavel.dolez.al@natur.cuni.cz.
The bacterial origin of mitochondria has been evidenced by a number of shared features with current bacteria, including some of the protein transport components. However, most of the original bacterial protein transport pathways have been lost from the mitochondria and replaced by the protein import apparatus. To some detail, mitochondria of Discoba represent an evolutionary intermediate stage as they carry the largest mitochondrial genomes encoding bacterial SecY and TAT trans-locases. By a multi-phylome approach we have analyzed eukaryotic proteomes for nuclear encoded genes, which are exclusive to Discoba. We show that their nuclei encode for about forty genes not found in other eukaryotic lineages. These include eight components of bacterial type II secretion system (T2SS). We show that mitochondria of Discoba express minimalist T2SS, which includes the pore forming secretin in the outer mitochondrial membrane and pseudopilin in the intermembrane space. Using the bacterial and yeast two hybrid assays, we are currently looking for the putative substrate of the ancient mitochondrial protein secretion pathway.
OCHER-COLORED GRANULES IN THE CILIATE CYCLOTRICHIUM SP. ARE EVIDENTLY DIATOM CHLOROPLASTS Hoshina Ryo1, Suzaki Toshinobu2, Kusuoka Yasushi3
1 - Nagahama Institute of Bioscience and Technology
2 - Kobe University
3 - Lake Biwa Museum wwhoseena@hotmail.com
As a crucial part of our exploration ofthe diversity of animal protists associated with algal endosymbionts, we have examined the ultrastructure and molecular characteristics of a ciliate ofthe genus Cyclotrichium collected from Lake Biwa, the largest and oldest lake in Japan. The ciliates, which are nearly spherical and about 100 ^m in diameter, are filled with hundreds of 2—3 ^m ocher-colored granules that impart their color to the whole cell. The internal structure of these granules is indistinct by light microscopy, but examination by SEM shows them to be chloroplasts consisting ofthree-layered thylakoid membranes. Many of the chloroplasts seem to be at different phases of digestion in food vacuoles (from
