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22 • "PROTIST—2016
Optimized U-insertion\deletion search software TAligner and usage of NGS technology enabled us to focus on molecular intermediates of editing process and build detailed editing graphs for all maxicircle cryptogenes. Reconstruction of editing process in cryptogenes showed that in most cases editing can proceed in a variety of alternative ways yielding ORFs with lots of aminoacid substitutions or even with alternative protein product. Our results suggest that editing can be the major driving force ofrapid adaptation to environment changes through the generation of proteins diversity.
GENETIC DIVERSITY OF CENTROHELID HELIOZOA IN BRACKISH INLAND WATERS OF RUSSIA
Gerasimova Elena, Plotnikov Andrey Institute for Cellular and Intracellular Symbiosis UB RAS, Orenburg, Russia [email protected]
Centrohelid heliozoa are ubiquitous, unicellular, non-ciliate phagoheterotrophs with slender radiating axopodia for trapping prey. Centrohelids have a cosmopolitan distribution; inhabit benthos and periphyton in both marine and freshwaters ecosystems, in communities they play role of predators grazing on other microorganisms. At present both genetic and morphological approaches for their taxonomy and classification are used. Morphological and genetic diversity of heliozoa in environmental saline and brackish waters has been studied very poorly. Genetic diversity of centrohelids with group-specific originally designed primers was studied by NGS with MiSeq (Illumina). Fifteen samples from brackish inland water bodies of Russia with mineralization 2-20%c were examined. As a result 40 OTUs were obtained. Most of the environmental OTUs (32) were aligned with Polyplacocystis contractilis (AB196984, NCBI) with support 99% and were placed inside Pterocystina clade. This fact indicates that the most common habitants in brackish waters are related to this particular genetic variant of centrohelida. Other OTUs with 26% and 28% support grouped with environmental centrohelidian sequences from hypersaline habitats and occupied a basal position in Pterocystina A clade.
The research was performed in the Center of Shared Scientific Equipment «Persistence of microorganisms» of ICIS UB RAS and was supported by RSF (14-14-00515) and RFBR (15-2902749,16-44-560234).
BIOGEOGRAPHY AND THE GENETIC STRUCTURE OF MORPHOSPECIES IN THE GENUS MAYORELLA (AMOEBOZOA, DISCOSEA, LONGAMOEBIA) Glotova A.A.
Department ofInvertebrate Zoology, Faculty ofBiology, St. PetersburgState University, Saint Petersburg, Russia [email protected]
Due to the lack of biogeographical data for the majority of naked lobose amoebae genera, the genetic structure of amoebae morphospecies have been previously observed only in several species from Flabellinia group (Amoebozoa, Discosea). Further extensive study of amoebae biogeography including species from different phylogenetic lineages is clearly required given the assumption of amoebae significance for freshwater microhabitat function based on their abundance. In this study Cox I and 18S rDNA genes were used as DNA barcodes in order to identify strains of the genus Mayorella (Discosea, Longamoebia) in addition to morphological data, that allowed to elucidate the morphospecies genetic structure and general principles of their distribution in a global scale and to evaluate resolving power ofvarious identification approaches. The samples were collected from distant freshwater habitats of North America, Europe and Russian Far East. Results contributed to the amoebae morphospecies conception which represents it as a limited set of genetic lineages. Supported with SPSU project 1.38.251.2014
DEEP SEQUENCING OF ANCIENT 18S RDNA
IN SEDIMENT CORES FROM CONTINENTAL
SHELVES OF CHINA
Gong J., Wang Y., Zhu P., Zhang Q.
Yantai Institute of Coastal Zone Research, Chinese
Academy of Sciences, Yantai 264003, China
Protists/phytoplankton in overlying waters and terrestrial biomaterials could be transported, deposited and buried in sediments on continental shelves of marginal seas. Some of these ancient DNA could be preserved, serving as a powerful proxy for reconstructing past regimes of the ecosystems. We obtained three sediment cores each about 2.5 meters in length from three sites at the Bohai Sea (the mouth of Yellow River, shorted as YR) and Yellow Sea (the northern basin, NYS, and southern basins, SYS). The DNA was extracted and quantified and subjected to high throughput sequencing of eukaryotic 18S rDNA fragment using Illumina MiSeq. Classification using pipelines indicated the
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presence of molecular signals of eukaryotic groups including Dinophyta, Stramenopiles, Ciliophora and Fungi. The relative proportions of these major groups were different among the three sites, with NYS and SYS were more similar to each other than to YR. Here we will briefly report the community composition and structure of microbial eukaryotes, and hope to link these signals in the near future with geochemical information to reflect the ecosystem conditions and changes of the north China Seas during the past thousands of years.
FEEDING SELECTION OF MIX-TROPHIC FLAGELLATE, POTERIOOCHROMONAS MALHAMENSIS, ON THE GREEN ALGAE OF CHLORELLA
Gong Yingchun12, Ma Mingyang12, Wei Chaojun12
1 - Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
2 - Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy ofSciences, Wuhan, China
Poterioochromonas is a very common mix-trophic flagellate in most freshwater environments, which can grow in autotrophic way or by feeding bacteria and other protists. Several species of algae have been reported to be the prey of Poterioochromonas, however little is known about whether and how Poterioochromonas has feeding selection on the prey. In this study, two strains of Chlorella sorokiniana showed significantly different defense ability on the grazing of Poterioochromonas. Both morphological and molecular approaches were combined to discover the factors which contributed to the defense ability on grazing. Light microscopic showed that the two strains didn't have much difference on the cell size and shape, however transmission electron microscopic observations and protein composition analysis indicated that the two strains have different cell wall composition and biochemical composition. Our research suggested that probably some protein in the cell wall of Chlorella played an important way to defense the grazing of Poterioochromonas.
THE GENOME OF UNDARIA PINNATIFIDA
AND UNDARIA PETERSENIANA: INSIGHTS
INTO KELP EVOLUTION
Graf L.1, Yang J.H.1, Lee J.M.1, Boo S.M.2, Yoon
H.S.1
1 - Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Korea
2 - Department ofBiology, Chungnam National Uni-
versity, Daejeon 34134, Korea [email protected]
The genus Undaria consists of large multicellular brown algal kelps. In Korea, U. pinnatifida and U. peterseniana are extensively cultivated (~500.000 tons/year) for human food and commercial extracts. Although phylogenetically related, the two species are ecologically distinct and have strikingly different distributions, morphologies and reproductive strategies. Spores of U. pinnatifida are produced in a specialized sporophyll that is localized on the lower part ofthe stipe whereas in U. peterseniana the sporophylls differentiate directly from the blades, which is a process similar to that for species of the genus Saccharina, another common kelp genus. We produced draft genomes for U. peterseniana and U. pinnatifida; with the previously released draft genome of Saccharina japonica, they represent the only genomic resources available for the kelps. We examined gene content, genome organization, and transposable elements dynamics. We will discuss the genomic differences between U. pinnatifida and U. peterseniana, and we will describe new insights into their evolutionary history; most notably, we will comment on the origin ofmulticellularity in the brown algae. Finally, the genome sequences for the two edible algae should be a new, major resource for kelp crop improvement and biotechnology.
NEW GENOMES OF UNICELLULAR HOLO-ZOANS SHED LIGHT ONTO THE ORIGINS OF COMPLEX ANIMAL GENE ARCHITECTURE Grau-Bove X.12, Ruiz-Trillo I.123
1 - Institut deBiologia Evolutiva (UPF-CSIC)
2 - Universitat de Barcelona
3 - Institucio Catalana de Recerca i Estudis Avangats [email protected]
The origin of animal multicellularity is a major event in eukaryotic evolution. Metazoans share many novelties in genome content and structure related to their multicellular lifestyle, like gene families (transcription factors and specific signaling pathways) and regulatory mechanisms (alternative splicing or enhancer-enabled introns). Since many of these traits predate metazoans, the study of their unicellular holozoan relatives is key to understand animal origins. We analyse the evolution of gene architecture using new ichthyosporean genomes, choanoflagellates and the filasterean Capsaspora owczarzaki, plus 40 other eukaryote genomes. This two-fold analysis focuses on the evolution of 1) intron/exon structure and 2) protein domain architectural rearrangements (which define gene families' function and diversification). Animals
