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surrounding the pseudostomal aperture. All trees generated using three nuclear rDNA datasets (18S rDNA, 28S rDNA, and the concatenated 18S + 28S rDNA) demonstrated that three photo-synthetic Paulinella species congruently formed a monophyletic group with robust bootstrap and Bayesian supports (>99% RAxML and 1.0 Baye-sian support), but their relationships remained unresolved within the clade in all trees. The P. longichromatophora, nevertheless, clustered consistently together with Paulinella strain FK01, but with very poor supported. Phylogenetic analyses inferred from plastid-encoded 16S rDNA and the concatenated dataset of plastid 16S+23S rDNA demonstrated that chromatophores of all photosynthetic Paulinella species formed a mono-phyly and fell within cyanobacteria clade with a close relationship to a-cyanobacterial clade containing Prochlorococcus and Synechococcus species with very robust supports of 100% bootstraps and 1.0 Bayesian posterior probabilities. Additionally, phylogenetic analyses of nuclear 18S rDNA and plastid 16S rDNA showed divergent evolution within the photosynthetic Paulinella population after a single acquisition of the chromatophore. After the single acquisition of the chromatophore, ancestral photosynthetic Paulinella appears to diverge into at least two distinct clades, one containing marine P. longichromatophora and freshwater Paulinella strain FK01, the other P. chromatophora CCAC 0185.
PREY SPECIFICITY AND MOLECULAR PHY-LOGENY OF THE THECATE MIXOTROPHIC DINOFLAGELLATE FRAGILIDIUM MEXI-CANUM
Kim S.1, Park M.G.2
1 - Department of Oceanography, Pukyong National University, Busan, Republic of Korea
2 - Department ofOceanography, Chonnam National University, Gwangju, Republic of Korea sunjukim75@gmail.com
Feeding mechanism and prey specificity of the mixotrophic thecate dinoflagellate Fragilidium mexicanum (strain Fm-LOHABE01) were examined using the culture isolated from Masan Bay, Korea in 2011 during summer blooms of the toxic dinoflagellate Alexandrium pacificum. We also used novel 18S and 28S rDNA sequences for F. mexicanum to explore inter-species relationships within the genus Fragilidium and to examine its phylogenetic relationships with morphologically similar species (Alexandrium, Goniodoma, and Pyrophacus). F. mexicanum (strain Fm-LOHABE01) fed on species belonging to three dinoflagellate genera (i.e. Alexandrium, Ceratium, and Heterocapsa) when
separately offered a variety of prey including dino-flagellates, raphidophytes, cryptophytes, and a ci-liate. In addition, F. mexicanum displayed different levels of specificity for species of Alexandrium. While F. mexicanum consistently fed on A. fundyense and A. pacificum, feeding on A. affine was observed only once. F. mexicanum ingested prey by direct engulfment through the sulcus, after capturing the prey by a tow filament. Phylogenetic analyses of 18S and 28S rDNA datasets demonstrated that Fragilidium sequences formed a monophyletic group with high statistical supports and diverged into four distinct clades. The first clade consisted of seven F. cf. duplocampanaeforme strains, F. subglobosum from New Zealand, and an unidentified Fragilidium sp. from Florida, USA. The second clade branched as a single sequence for F. subglobosum from Denmark and formed a sister lineage to F. cf. duplocampanaeforme, with weak statistical support. The third clade included Fragilidium sp. EUSK D from Angola, as well as Korean strains of F. mexicanum and F. fissile, and was very strongly supported. The last clade contained the five most divergent sequences of F. subglobosum strains. Further, phylogenetic analyses revealed that the genera Fragilidium and Pyrophacus were sister to a clade that included Alexandrium and Goniodoma. Pyrophacus was a sister to a clade containing members of the genus Fragilidium.
TWO ENIGMATIC GENERA ARE ONE? COMPARISON OF BELONOCYSTISMARINA KLI-MOV, ZLATOGURSKY, 2016 WITH LUFFISPHAERA SPP Klimov V.I.
St.Petersburg State University, Faculty of Biology, Department of Invertebrate Zoology JoeRex40@ya.ru
Belonocystis Rainer, 1968 and Luffisphaera Belcher and Swale, 1975 are enigmatic genera, which currently lack supergroup affiliation. The genus Belonocystis was studied mainly on the light-microscopy level, while the genus Luffisphaera was studied only with electron microscopy. Recently provided ultrastructural data on Belonocystis gave an opportunity to compare these taxa using one and the same method. This analysis discovered many similarities in the organization of the cell structure as well as in morphology of the coverings. It was clearly shown that surface structures of Belonocystis represent not a solid capsule, but giant scales, which are similar to those of Luffisphaera. Comparison of the scales has revealed that some Belonocystis species were similar to Luffisphaera species more than inside the genus. Each scale of B. marina was
36 • "PROTIST—2016
associated with a short cytoplasmic outgrowth and the same was shown for all of Luffisphaera spp., studied for that matter. All organells, described for Luffisphaera were found in Belonocystis and shown to have almost identical organization. Both have tubular mitochondrial cristae and vacuoles associated with stacks of rough endoplasmic reticulum cisternae and neither of them was shown to have kinetosomes. B. marina was the first record of marine species for Belonocystis, which again put it closer to Luffisphaera, initially recorded in marine and freshwater habitats. It's possible that the subsequent study of Luffisphaera and extra Belonocystis isolates in future may lead to a fusion of both or to transfer some species from one genus to another. Study was supported with RFBR grants 15-04-18101_a, 15-29-02749-ofi_m.
HIGH ARCTIC BENTHIC FORAMINIFE-RANS DURING THE POLAR NIGHT: DORMANCY OR ACTIVE FEEDING? Knyazeva O., Korsun S.
Dept Invertebrate Zool, Biol Faculty, St-Petersburg
Univ, Russia
s_korsun@mail.ru
Benthic foraminiferans are the vast meiobenthic group of protists widely represented in all marine habitats including the high Arctic. Although some foraminifera species are known to feed on bacteria, the majority of these protists keep to an algal diet, preying on diatoms and dinofllagelates. Some species are also capable of capturing prey chloroplasts and maintaining them functionally active, thus performing kleptoplasty, which also results in a change of the host cytoplasm coloration. Given the seasonal transitions to long periods of darkness performed in high latitudes and leading to scarceness of primary production, one would expect foraminiferans to face absence of prey algae and starvation, the latter resulting in either death or dormancy of the most part of population. Nevertheless, our results contradict such assumptions. In January 2015 and 2016, during the Marine Night cruise with RV Helmer Hanssen, we collected live specimens in the Kongfjorden area, Svalbard. All major species (Nonionella labradorica, Islandiella helenae, Cassidulina reniforme, Elphidium excavatum, Elphidium bartletti) had brightly species-specifically colored cytoplasm implying they did not starve but had access to algal food. Transmission electron microscopy revealed that all specimens had well-developed mitochondria, Golgi apparatus and endoplasmic reticulum, therefore being meta-bolically active throughout the winter season. Moreover, some foraminiferans possessed intact
chloroplasts within cytoplasm. These results strongly indicate that high Arctic benthic foraminifera are not dormant during the polar night, and they access algal diet.
Supported by Research Council of Norway grant 226417/E10 and RFBR grant 14-04-93083.
TIM17 FAMILY PROTEIN IN THE MITO-SOMES OF GIARDIAINTESTINALIS Kolisko M.1, Martincova E.2, Voleman L.2, Roger A.J.3 4, Dolezal P.2
1 - Canadian Institute for Advanced Research, Department ofBotany, University ofBritish Columbia, Vancouver, Canada
2 - BIOCEV — Biotechnology andBiomedicine Center of the Academy of Sciences and Charles University in Vestec and Department of Parasitology, Faculty of Science, Charles University in Prague, Czech Republic
3 - Centre forComparative Genomics and Evolutionary Bioinformatics, Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
4 - Program in Integrated Microbial Biodiversity, Canadian Institute for Advanced Research, Halifax, Nova Scotia, Canada lubos.voleman@gmail.com
Protein transport across the mitochondrial membranes is mediated by the TIM, TOM and SAM complexes. These complexes are common to all supergroups of eukaryotes suggesting that they were already present in the last eukaryotic common ancestor. However, mitochondria-related organelles of Giardia intestinalis known as mitosomes were thought to lack both the SAM (a beta barrel assembly complex in the outer membrane) and the TIM (the translocase of the inner membranes) their membranes. The question was, how proteins pass the inner mitosomal membrane. Here, we present the identification of Tim17 family protein in giardia mitosomes, which represents a core channel forming subunit of the TIM complex. The bioinformatic identification of this highly diverged subunit was only possible by including newly obtained orthologous metamonad sequences in the sequence profiles. We demonstrate that giardia Tim17 is specifically targeted to mitosomes, where it interacts with other proteins involved in the protein transport and the iron-sulfur cluster assembly.
HETEROTROPHIC NANOFLAGELLATES IN THE PLANKTON OF LAPTEV SEA Kopylov A.I.1, Zabotkina E.A.1, Kosolapova N.G.1, Romanenko A.V.1, Sazhin A.F.2 1 - Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Russia
