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Protistology ■ 13
collections of microorganisms", St. Petersburg, Russia
2 - Institute ofCytology, Russian Academy ofSciences, St.Petersburg, Russia
3 - Zoological Institute of the Russian Academy of Sciences,St. Petersburg, Russia
4 - Life Science Research Centre, Faculty ofScience, University of Ostrava
batsnwr@mail.ru
At present the taxonomy of Archamoebae is based on molecular phylogeny, and it is problematic to find non-molecular synapomorphies for different lineages within this group. The family Pelomyxidae includes two archamoebal genera: Pelomyxa and Mastigella. All pelomyxae and most mastigellae have various prokaryotic endocytobionts. Host-symbiont composition could be useful for the phylogeny reconstruction, but information about such associations is controversial. We analyzed consortia of prokaryotic symbionts in Mastigella nitens and 11 Pelomyxa spp. There are two kinds of such consortia within pelomyxid cells: binary and ternary ones (with 2 and 3 symbionts correspondingly). The composition of these associations revealed to be species-specific. According to morphological characters, autofluorescence ability and results of Gram staining 4 main types of cytobionts can be distinguished. One of them is common to all investigated pelomyxae and M. nitens. Morphologically similar prokaryotes can be also found in the cytoplasm of other Mastigella spp. Distribution of the remaining types of cytobionts among hosts species is not correlated with the molecular phylogeny of Archamoebae based on 18S rRNA gene. We propose the ability to form symbiotic associations with prokaryotes as a shared feature of all Pelomyxidae. This work was supported by the grant RFBR 15-04-00396_a. Scientific research were performed at the Center for Culturing Collection ofMicroorganisms and "Chromas" Center of Research park of St. Petersburg State University.
THE GENOME EVOLUTION OF THE THER-MOACIDOPHILIC CYANIDALES RED ALGAE Cho C.H.1, Park S.I.1, Ciniglia C.2, Yoon H.S.1
1 - Department of Biological Sciences, Sungkyunkwan University, Korea
2 - Department of Environmental, Biological and Pharmaceutical Science and Technologies, Second University of Naples, Italy cndgus56@gmail.com
The Cyanidiales is an early diverged red algal group that comprised of seven species with numerous cryptic species. They are asexual, unicellular photosynthetic eukaryote, which usually thrive in
extremophilic environments (pH1.5~3, 35~55oC). Cyanidiales species are reported from hot springs around world including Yellowstone National Park (US), Italy, Iceland, New Zealand, Indonesia, and Japan. Some Cyanidiales species are also found in acidic bogs, mesophilic caves, interlithic or endolithic environments. In addition, they show trophic differences being either autotroph or mixotroph. From previous researches, the genomes of Cyanidiales are highly reduced, but horizontally acquired from bacteria to adopt in extreme habitats. Here we report two nuclear genomes of Galdieria maxima and Cyanidium caldarium and conduct comparative genome analysis with three available genomes of Cyanidioschyzon merolae, Galdieria sulphuraria, and Galdieriaphlegrea. We will discuss gene contents, mutation rates, and unique horizontal gene transfer that related to the environmental adaptation.
EVOLUTION OF HEME BIOSYNTHESIS PATHWAY IN ALGAE WITH COMPLEX PLASTIDS Cihlar J.12, Fussy Z.1, Obornik M.12
1 - Biology Centre CAS, Ceske Budejovice, Czech Republic
2 - University of South Bohemia, Ceske Budejovice, Czech Republic
obomik@paru.cas.cz,
Tetrapyrroles are organic compounds essential for life. Organisms are either synthesizing tetra-pyrroles or they have to obtain them from their environment, host or prey. We showed that the composition of the biosynthetic pathway is shaped by passed endosymbiotic evens in eukaryotes. We map the pathway in phototrophic eukaryotes, particularly in algae with secondary or other advanced plastids, by investigating origins of involved enzymes and predicting their location in the cell of the euglenophyte Euglena gracillis, the chlorarachniophyte Bigelowiella natans, the cryptophyte Guillardia theta, the dinoflagellate with green secondary plastid Lepidodinium chlorophorum, and dinoflagellates bearing diatom endosymbiont (also called "dinotoms") — Glenodinium foliaceum, Kryptoperidinum foliaceum and Durinskia baltica. Chlorarachniophytes and euglenophytes still possess two independently operating tetrapyrrole pathways with the first common precursor S-aminolevulinic acid synthesized either by the C4 pathway in two steps using the mitochondrially located ALA synthase (ALAS), or by the plastid located C5 pathway by consecutive enzymes glutamyl-tRNA reductase (GTR) and glutamate-1-semiladehyde 2,1 aminomutase (GSA-AT). We propose that such arrangement of the pathway was ancestral for all
14 • "PROTIST—2016
phototrophic eukaryotes. Other algae show partial (cryptophyte) or total (dinoflagellates) reduction of the redundant mitochondrially-cytosolic pathway. In dinotoms, two redundant plastid located pathways are present suggesting a presence of the two plastids of different origins in the dinotom cell. Although L. chlorophorum and B. natans contain chlorophyte-derived plastids, enzymes involved in tetrapyrrole biosynthesis are dominantly of rhodophyte origins. This may suggest an early acquisition of the rhodophyte-derived secondary plastid through the secondary endosymbiotic event on the root of SAR group.
MICROBIAL EUKARYOTES FROM THE DEEP: REVEALING THE DIVERSITY OF PROTISTS AND THEIR TROPHIC RELATIONSHIPS AT HYDROTHERMAL VENTS Countway P.D.1, Pasulka A.L.2, Mesrop L.Y.3, Hu S.K.3, Heidelberg K.B.3, Coyne K.J.4, Cary S.C.5, Caron D.A.3
1 - Bigelow Laboratory for Ocean Sciences
2 - California Institute of Technology
3 - University ofSouthern California
4 - University of Delaware
5 - University of Waikato pcountway@bigelow.org
Protists in the deep-sea are a diverse mixture of taxa that are either transported there by sinking or occur there as endemic species. It is not uncommon for the closest genetic relatives of deep-sea protists to be found in samples from other deep-sea habitats thousands of kilometers away. In other cases, the nearest relatives of deep-sea protists are from equally distant, but shallow-water habitats with similar characteristics to the deep-sea locales (e.g., low-oxygen or high-temperature sediments). Many of the most conspicuous protists at hydrothermal vents are ciliates and small flagellates that rely on the copious bacterial production occurring in the proximity of vent ecosystems. We investigated the diversity and activity of marine protists from two deep-sea hydrothermal vent ecosystems including those at Guaymas Basin (Gulf of California, N. Pacific) and 9-North (Eastern Tropical N. Pacific). Complementary molecular techniques were employed to reveal the full breadth of protistan diversity, the diversity of the active fraction, and the taxono-mic identities of some of the most conspicuous and active deep-sea ciliates. Clone libraries based on RNA extractions revealed a substantially greater proportion of the protists that appeared to be the most active via microscopy, while libraries based on DNA captured the diversity of both endemic organisms and those that sank into the vent eco-
system. Single ciliates were hand-isolated and subjected to whole genome amplification, prior to cloning and sequencing. This approach identified specific protistan taxa that were likely some of the most active members of the deep-sea community of microbial eukaryotes.
FIRST RECORDS OF MOSS CILIATES IN MEXICO
Cruz Jimenez G.1, Mayén-Estrada R.2, González Adame G.1
1 - Lab. de Ecología, Instituto de Análisis Ambiental, Universidad de la Sierra Juárez.. Av. Universidad, Ixtlán de Juárez,, C. P. 68725, Oaxaca, México
2 - Lab. Protozoología, Depto. Biol. Comparada, Fac. Ciencias, Universidad Nacional Autynoma de México, Circuito Ext. s/núm. Ciudad Universitaria, C. P. 04510, Ciudad de México, Mexico cruzgera16@hotmail.com
Mosses (Bryophyta) are not vascular gregarious plants that require some environmental characteristics to grow, i. e. the presence of some moisture degree, doing possible the establishment of ciliate communities like those that ocurre in peatlands. Mexico has a diversity of 984 species of mosses and for ciliates about 959 species have been recorded in several habitats, however the study of ciliates associated to these plants remains unknown until the present. The aim of this work was to record the ciliate community in Campylopus pilifer Brid during the summer of the year 2015 in the Sierra Juárez, Oaxaca. Samples were manually collected and observed alive using bright field and DIC microscopy. We also employed silver impregnation techniques for species identification. We recorded five species of ciliates: Colpoda inflata, C. aspera, Colpoda sp., Vorticella infusionum and Vorticella sp. in C. pilifer belonging to habitats with different environmental characteristics. These findings represent the first moss-ciliate record for Mexico. Keywords: Ciliates, Bryophytes, México, Moss, Oaxaca.
Acknowledgements. To Biyl. M. Reyes and M. C. Maricela Vicencio, Facultad de Ciencias, UNAM, for their support with technical procedures.
POPULATION STRUCTURE OF PLANKTONIC MICRO-ORGANISMS (TINTINNID CILIATES OF THE MICROZOOPLANKTON) IN THE SOUTH PACIFIC OCEAN: COMPARISON OF A HIGH PRODUCTIVITY BLOOM AND A TYPICAL OLIGOTROPHIC SITE Dolan J.R.
CNRS Laboratoire d'Océanographie de Ville-franche-sur-Mer
