CC BY
22
12 • "PROTIST—2016
plankton biomass has also increased 1.9 and 1.3 times, respectively. Along with these changes, a redistribution of the total biomass of the plankton community has occured between the pelagic and littoral parts. In the pelagic zone of the lake the increase was most significant, 3.8 times, and in the littoral zone it amounted 1.3 times. The share of protists in the unicellular plankton biomass in the pelagic zone remained unchanged, while in the littoral zone it increased 2.3 times. Protist's contribution into the total plankton biomass in the pelagic zone increased 1.3 times, and in the littoral 3.4 times. These changes were mainly related to the increased role of the cryptophytes, dinoflagellates and ciliates, especially mixotrophic. In the context of eutrophication the most significant correlations of individual groups ofprotists were registered with the concentrations of phosphorus, ammonia nitrogen and chlorophyll a. The influence of environmental factors on the peculiarities ofprotist distribution and ratios of their groups are discussed.
IOTANEMA SPIRALE GEN. ET SP. NOV., A NEW ENDOBIOTIC LINEAGE OF FORNI-CATA WITH STRIKINGLY SIMPLIFIED MORPHOLOGY AND ULTRASTRUCTURE Cepicka I.1, Yubuki N.1, Zadrobilkova E.12
1 - Department of Zoology, Charles University in Prague, Vinicna 7, 128 44 Prague 2, Czech Republic
2 - Centre for Epidemiology and Microbiology, National Institute of Public Health, Srobarova 48, 100 42 Prague, Czech Republic [email protected]
Fornicata is a lineage of excavates living in low oxygen environments and lacking a conventional mitochondrion. Three main morphological/ecological subgroups of Fornicata are recognized: free-living Carpediemonas-like organisms (CLOs) from marine habitats and two parasitic/commensal lineages living in animal hosts, retortamonads and diplomonads. The research of Fornicata centers on evolutionary perspectives such as transition from free-living lifestyle to parasitic one and mitochondrion transformation. Nonetheless, current modest knowledge of the biodiversity of Fornicata limits our ability to draw the whole picture of evolutionary history of this group. The free-living CLOs are particularly important due to the plesiomorphic traits of excavates. In this study, we cultured a novel member of Fornicata, Iotanema spirale gen. et sp. nov., isolated from fresh feces of a gecko. I. spirale exhibits several unique features not seen among fornicates. It possesses a single flagellum and a highly reduced cytoskeletal system with a single microtubular root, two fibers, and
dorsal fan; the excavate ventral groove is missing. SSU rRNA gene analyses demonstrated that I. spirale branches as a sister lineage to the free-living CLO Hicanonectes teleskopos and its relatives, which means that it represents the third known endobiotic lineage of Fornicata.
SPATIOTEMPORAL DISTRIBUTION OF SPECIES DIVERSITYAND COMMUNITY STRUCTURE OF CILIATES IN INTERTIDAL SANDY SEDIMENTS OF HUOKUN'AO BEACH, NANJI ISLANDS (EAST CHINA SEA, CHINA) Chen X.1, Chen W.2, Cai H.2, Xu K.1
1 - Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
2 - Nanji Islands National Marine Nature Reserve Administration, Pingyang 325401, China [email protected]
In intertidal sediments, ciliates are a highly diverse and quantitatively dominant group, whose community structure, in some sense, may reflect the condition of environmental quality. We investigated the spatiotemporal distribution of species diversity and community structure of ciliates in the intertidal sandy sediments of Huokun'ao beach, Nanji Islands National Marine Natural Reserve based on sample collections in November 2013 (autumn), February (winter), May (spring) and August (summer) 2014. The results showed highly diverse and abundant ciliates in the intertidal sediments of the beach, where a total of 148 species representing 19 orders and over 70 genera were identified. The abundance and species composition of benthic ciliates showed significant correlation with seasons and sediment depths. Bacterivorous ciliates constituted the most abundant group, followed by carnivores and algivores. The predominance of bacterivores indicated that the ciliate community in the intertidal sediment of Huokun'ao was not a typical interstitial ciliates fauna, but a pattern similar to those in muddy sand sediments with high level of organic matter. This is likely a subsequent effect oflong-term human activities. In spite of the impact, the high diversity of ciliates indicates that the benthic environment in the Huokun'ao beach and its surrounding area is in fair condition, which is attributed to the biodiversity conservation measures adopted, e.g. the relocation of surrounding residents and facilities.
PROKARYOTIC ENDOCYTOBIONTS OF PELOMYXIDAE
Chistyakova L.V.1, Berdieva M.A.2, Kostygov A.Yu.34, Frolov A.O.3
1 - Centre of Core Facility of SPSU "Culturing
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
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 [email protected]
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
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
