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from the headwaters to the mouth. The maximum development of the protists received at the mouth of Warm Creek. Here the number of protists in 50, and biomass 25 times higher than the average. Thus, the protists of a small river with significant agricultural load, have high species diversity. The trends of increasing species richness, abundance and biomass of protists from the source to the mouth of the watercourse.
THE PROTISTAN SPECIES MAXIMUM CONCEPT AND ITS IMPLICATIONS TO INVASIVE BIOLOGY Telesh I.V.
Zoological Institute RAS, St. Petersburg, Russia Irena.Telesh@zin.ru
The paper discusses possible implications of the novel protistan species maximum concept for the predictive modelling of ecosystem resilience and vulnerability to alien species invasions. Recent development of the protistan species maximum concept for the challenging zone of critical salinity 5-8%o (horohalinicum), where macrozoobenthos experience destructive osmotic stress (Telesh et al., 2011), is presented. This concept arose from the discovery that not all brackish waters are poor in plankton species, which was exemplified by the Baltic Sea data. The concept has gradually evolved to the understanding that in the environment with sharp salinity fluctuations community regulations and life strategies of small unicellular planktonic organisms differ substantially from those of large multicellular bottom-dwellers. Special efforts were undertaken to define the major organismal traits and environmental factors responsible for this new peculiar biodiversity pattern. Phytoplankton cell size, seasonality in development, and water salinity were tested as key characteristics. A long-term (1972-2006) phytoplankton dataset from the Baltic Sea ("the sea of invaders") was analyzed by means of correlation analysis, non-metric multidimensional scaling, and rarefaction analysis. Results prove statistically that algal cell size minimum underpins the protistan species maximum in the horohalinicum. Seasonality in phytoplankton development promotes the shift in community composition towards dominance of the small-sized species in the critical salinity regions. The protistan species maximum in the horohalinicum is largely backed up by the significant between-sample variation in species richness in the highly changeable brackish-water environment. The work was funded in part by the Russian Foundation for Basic Research, project 15-29-02706.
PROFILING THE PROTOZOAN TAXONO-MIC AND FUNCTIONAL DIVERSITY OF AN ANTARCTIC DRY VALLEY Thompson A.R.1, Buelow H.2, Takachs-Vesbach C.2, Adams B.J.1
1 - Department ofBiology, Brigham Young University
2 - Department ofBiology, University of New Mexico andy_thompson@byu.edu
The McMurdo Dry Valleys of Victoria Land Antarctica are some of the harshest terrestrial habitat on earth. At 78°S and 163°E, the average temperature of the region is <-20°C, precipitation is <10 cm yr -1 and the growing period during the austral summer lasts only a few months when the landscape is warmed enough for glacier-fed streams to flow and some permafrost to thaw. Life is almost entirely microbial in these valleys and the landscape is dominated by extremely dry soils that are highly saline, oligotrophic, basic in pH and subject to frequent freeze-thaw cycles. This system is a great outdoor laboratory as the extreme conditions have reduced complexity such that intricate interactions between soil taxa can be unraveled. Our research aims to investigate protozoan diversity in these valleys in order to understand fundamental aspects of protozoan ecology that can be applied broadly. However, our understanding of the taxonomic diversity, distribution and functional roles of these organisms in these valleys is still lacking. To begin to address this, a variety of soils were sampled from two valley systems and metagenome and transcriptome datasets were constructed using next generation sequencing. Our results so far suggest that there is greater taxonomic and functional diversity than was previously thought present, with relatively high representation from many major ciliate and cercozoan clades. Future sequencing efforts will undoubtedly shed more light on distribution and richness of individual OTUs.
MANY PREVIOUSLY INCERTAE SEDIS AMO-EBOZOANS FIND A HOME WITHIN THE CENTRAMOEBIDA
Tice A.K.12, Shadwick L.L.3, Spiegel F.W.3, Geisen S.4, Fiore-Donno A.M.4, Bonkowski M.4, Dumack K.4, Kang S.12, Brown M.W.12
1 - Department ofBiological Sciences, Mississippi State University, Mississippi State, MS, 39762
2 - Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, 39762
3 - Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701
4 - University of Cologne, Institute of Zoology,
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DepartmentofTerrestrialEcology, Cologne, Germany at1422@msstate.edu
The Centramoebida is a group of amoebozoans with flattened trophic cells that display finely pointed subpseudopodia and a prominent lamellate microtubular organizing center (MTOC). This group of amoebozoans has received considerable attention from the broader scientific community due to the pathenogenic nature and ecological importance of some of its members. Here we increase the known diversity of the Centramoebida by demonstrating through multi and single gene phylogenetics along with light and electron microscopy that the formally incertae sedis amoebozoans " Protostelium" pyriformis, "Protostelium" arachisporum, and Stereomyxa ramosa belong within the Centramoebida. We also describe Vacuolamoeba acanthaformis n.g. n.sp. a new centramoebid isolated from soil in Tibet. Our phylogenetic analyses recover a highly supported Centramoebida that includes highly supported clades comprised of "P." arachisporum, Stereomyxa ramosa and Vacuolamoeba acanthafor-mis respectively. We also show "P." pyriformis is robustly nested within the genus Acanthamoeba making it the first reported protosteloid member of the genus. As a result of these analyses, we formally transfer "Protostelium" arachisporum into the genus Luapelameoba and "Protostelium" pyriformis into the genus Acanthamoeba establishing the combinations Luapeleamoeba arachisporum n. comb. and Acanthamoeba pyriformis n. comb. Our results greatly increase the known diversity of this medically and ecologically important group, and further demonstrate the widespread nature of sporocarpic fruiting across the tree of Amoebozoa.
THE EVOLUTIONARY IMPORTANCE OF PREDATORY FLAGELLATES: NEW DEEP BRANCHES ON THE EUKARYOTIC TREE OF LIFE
Tikhonenkov D.V.1, Janouskovec J.2, Hehenberger E.3, Burki F.4, Gawryluk R.3, Karnkowska A.3, Mylnikov A.P.1, Keeling P.J.3
1 - Institute for Biology of Inland Waters, Russian Academy of Sciences
2 - Department ofGenetics, Evolution & Environment, University College London
3 - Botany Department, University ofBritish Columbia
4 - Systematic Biology Department, Uppsala University tikho-denis@yandex.ru
The origin and early radiation of major protist supergroups are linked to understanding key transitions in the evolution fo eukaryotes: endosymbiosis, genome evolution, and morphological novelty. This understanding is often limited by the absence of
reliable comparators; organisms with ancestral or intermediate features that represent sister groups of well-known taxa. Recent studies on the diversity of heterotrophic protists and environmental sequence data have indicated that many such "sister" lineages exist but remain insufficiently known primarily because they are not available in stable cultures. Among heterotrophs, predatory protists are of particular interest because their diversity may be the least understood of all protists: they are comparatively rare in natural samples and often difficult to maintain in the laboratory. However, their ability to feed on protozoa and microalgae is relevant to understanding the role ofphagotrophy in the origin of mitochondria and plastids, and many represent deep-branching evolutionary lineages that could help us illuminate the origin of major protist supergroups and resolve their relationships. Here we report the establishment of multiple cultures ofrare, free-living predatory flagellates, which occupy basal or intermediate evolutionary positions within major eukaryotic supergroups (Alveolata, Stramenopiles, Rhizaria, Opisthokonta, Kinetoplastida), or represent independent deep-branching eukaryotic lineages. Molecular and morphological data from these isolates reveals ancestral and unique morphological and ultrastructural features, slowly evolving nuclear genes, and large, slow-evolving mitochondrial gene sets.
This study was supported by the Russian Science Foundation (grant no. 14-14-00515).
DEVELOPMENT OF THE INTEGRATED INFORMATION WEB-SYSTEM ON A BIODIVERSITY OF PROTISTS "PROTIST.RU" Tikhonenkov D.V.1, Tychkov A.Yu.2, Azovsky A.I.3, Bobrov A.A.3, Plotnikov A.O.4, Tsyganov A.N.2, Mylnikov A.P.1
1 - Institute for Biology of Inland Waters, Russian Academy of Sciences
2 - Penza State University
3 - Moscow State University
4 - Institute for Cellular and Intracellular Symbiosis, Russian Academy of Sciences tikho-denis@yandex.ru
Protists are the most heterogeneous at cellular and molecular levels group of eukaryotes. They play an important role in ecosystem functioning as a part of microbial communities and have a high potential for human practical activity as a resource for the development of biotechnologies. Inventory, systematization, and integration of the data on the diversity of protists are of primary importance. We have made the technical platform and started the development of web-system, which allows
