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18 • "PROTIST—2016
THE STABILITY OF THE MARINE CILIATE COMMUNITY TO ENVIRONMENTAL CHANGES
Esaulov A.S.1, Mazei Yu.A.12, Burkovsky I.V.2
1 - Penza State University
2 - Lomonosov Moscow State University [email protected]
A complete study of processes that occur during the formation of marine communities and their stability to factors of the environment requires information for a sufficient period of time that would cover a succession of many hundreds or even thousands of generations of organisms. Studies like these have been conducted by a team of biologists at the White Sea for a several decades. In field experiments on the transplantation of fragments of natural communities of marine ciliates into an estuary, restoration of the initial or modified species structure was observed after a short period of adaptation of the organisms. Their responses to new conditions included both species-specific reactions and group reactions (the synergistic effect). In a group, species are able to sustain larger amplitudes of variations in environmental factors than if they were separate and they can even occupy extreme biotopes. Under the conditions of the experiment, as well as in nature, a multitude of structural variants of the psammophile community (multivariability of structure) were created from the united pool of species through the recombination of their abundances. In total, the formation and maintenance of communities of unicellular organisms is determined by a complex mechanism that includes physiological (tolerance), population (reproductive properties), cenotic (interspecific interactions), and stochastic (reaction to environmental fluctuations) processes; their relative roles depend on the level of organization of the community (succession stage) and on the range of variations in environmental factors.
AGGREGATIVE BEHAVIOR, CELL SIGNALING AND MORPHOMETRICS IN ENTAMOEBA DISCRIMINATION STUDIES Espinosa A.12, Paz-y-Mino-C G.2, Hackey M.1, Rutherford S.3
1 - Department of Biology, Roger Williams University
2 - New England Center for the Public Understanding of Science, Roger Williams University
3 - Department of Environmental Science, Roger Williams University
Studies on clone- and kin-discrimination in protists have proliferated during the past decade. We report
clone-recognition experiments in seven Entamoeba lineages (E. invadens IP-1, E. invadens VK-1:NS, E. terrapinae, E. moshkovskii Laredo, E. moshkovskii Snake, E. histolytica HM-1:IMSS and E. dispar). We demonstrate that amebas themselves can discriminate self (clone) from different (themselves versus other clones). In mix-cell-line cultures between closely-related (E. invadens IP-1 versus E. invadens VK-1:NS) or distant-phylogenetic clones (E. terrapinae versus E. moshkovskii Laredo), amebas consistently aggregated with same-clone members. Additionally, we identified six putative cell-signals secreted by the amebas (RasGap/Ankyrin, coronin-WD40, actin, protein kinases, heat shock 70, and ubiquitin) and which known functions in Entamoeba spp. included: cell proliferation, cell adhesion, cell movement, and stress-induced encystation. Each clone was characterized morphometrically (length, width, and cell-surface area) and documented how they differed statistically from one another (as per single-variable or canonical-discriminant analyses). This is the first multi-clone characterization of Entamoeba spp. aggregative behavior, cell-signaling secretion, and morphometrics in the context of clone-recognition. Because unicellular eukaryotes belong to ancient and highly diverse phylogenetic lineages, occupy all environments on Earth, and participate in complex interactions with other organisms (as hosts, symbionts or parasites), they can be robust model systems to study the implications of taxa, clone and kin discrimination/recognition in ecological and evolutionary contexts, and with emphasis on basic or applied sciences.
DIVERSITY AND ABUNDANCE OF KINETO-PLASTIDS IN THE WORLD OCEAN Flegontova O.12, Flegontov P.32, Logacheva M.D.4, Konovalova O.P.4, Malviya S.5, Bowler C.5, Lukes J.126, Horâk A.12
1 - Faculty of Science, University of South Bohemia, Ceské Budëjovice, Czech Republic
2 - Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceské Budëjovice, Czech Republic
3 - Faculty ofScience, University ofOstrava, Ostrava, Czech Republic
4 - Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
5 - Ecole Normale Supérieure, PSL Research University, Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Paris, France
6 - Canadian Institute for Advanced Research, Toronto, Canada
Protistology ■ 19
Kinetoplastids include important protozoan parasites of humans, other mammals and plants. The key genera, Trypanosoma and Leishmania, belong among the best-studied unicellular eukaryotes. However, our knowledge of diversity and distribution of basal, mostly free-living heterotrophic lineages is rather limited, despite their potential importance in understanding the evolution of parasitism in kinetoplastids. We have analyzed kinetoplastid 18S rDNA barcodes (V9 region) in a large global metabarcoding dataset, combining 123 stations of the Tara Oceans. According to our results, the majority of planktonic kinetoplastids belonged to Neobodonida: about 90% reads and 70% OTUs. Compared to their sister-clade, diplo-nemids, kinetoplastids show similar distribution patterns: both are more abundant in the mesopelagic than in the photic zone, in the piconano-plankton (<5 ^m in size), and demonstrate no apparent biogeography. Both groups are dominated by a few abundant cosmopolitan OTUs: neobodonids and Bodo sorokini in the case of kinetoplastids. However, kinetoplastids were much less abundant in all depth zones (on average 0.2% of eukaryotic reads per sample, and ranging from 0% to 10.8%), and much less diverse (~650 OTUs vs. >50,000 OTUs for diplonemids). Also, unlike diplonemids, planktonic kinetoplastids show only weak vertical structure with 23% OTUs present in all sampled depth zones: surface, deep chlorophyll maximum, and mesopelagic. Rarefaction curves revealed that kinetoplastid diversity was saturated in the whole dataset, as well as in separate depth zones, size fractions, and oceanic provinces. Our results suggest kinetoplastids are rare but ubiquitous component of the global plankton.
FISH TECHNIQUE AS A POSSIBLE TOOL FOR CORTEX INVESTIGATION IN ARMO-PHOREAN CILIATES (CILIOPHORA, ARMO-PHOREA) Fokin Sergei I.12
1 - Department ofInvertebrate Zoology, St. Petersburg State University, 199034 St. Petersburg, Russia
2 - Department of Biology, Pisa University, 56126 Pisa, Italy
Fluorescence in situ hybridization (FISH) is nowadays common molecular technique. One of possible application of this technique is in situ indeti-fication and phylogenetic position of uncultured bacterial endosymbionts (Amann et al., 1991). For this purpose rRNA-targeted oligonucleotide probes were developed for different groups of bacteria. In protistological studies alphaproteobacterial and
eubacterial probes which able to visualize wide rage of most common bacterial endosymbionts are used more often. During long time of using (Fokin et al., 1996), I have found that sometimes, using the same protocol, these probes specifically can bind also to several cortical stuctures of ciliated protists, namely: kinetosomes, extrusomes, and cortical granules. The reason of such unusual FISH results is not so clear from molecular point of view. However, this "impregnation technique" could be useful for morphological and taxonomical investigations of ciliates. In many cases (representatives of Nassophorea, Plagiopylea, Heterotrichea, and Spirotrichea) such decoration could be find out only sporadically, but for Armophorea members the cortical granules always impregnated by both oligonucleotide probes. In majority of heterotrichs in which presence of cortical granules is very common feature I could not able to get such a FISH impregnation. Phenomenon discovered not only allows to use FISH technique in some cases for the ciliate's kinetome investigation, but puts a question about origin of cortical granules in Armophorea and in other ciliate lineages. Unusual labelling are illustrated by FISH images of different Metopus spp., Brachanella spiralis, Copemetopus sp., Blepharisma sp., Euplotes crassus, Sonderia vorax, and Pseudomicrothorax dubius.
AN ALVEOLATE ALGA VITRELLA BRASSI-CAFORMIS FORMS ZOOSPORES BY BUDDING
Fussy Z.1, Krucinska J.12, Esson H.J.1, Obornik
M.1-2-3
1 - Institute of Parasitology, Biology Centre, Czech Academy of Sciences, Ceske Budejovice
2 - Faculty of Science, University of South Bohemia, Ceske Budejovice
3 - Centre Algatech, Institute of Microbiology, Czech Academy of Sciences, Trebon [email protected]
The ease of cultivation and availability of genomic data promoted intense research of free-living relatives of apicomplexans, Chromera and Vitrella, to understand evolutionary processes leading to the emergence ofparasitism. Recently the ultrastructure was revealed of an apically located structure of Chromera velia, supposedly homologous to the apical complex essential for host invasion in Apicomplexa. Yet, Chromera and Vitrella differ significantly in their physiology, morphology, phylogenetic position and genomic features, and Chromera is likely the more evolutionary advanced of the couple. Hence, in an expectation of more ancestral features, we inspected in further
