CC BY
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Protistology ■ 81
DepartmentofTerrestrialEcology, Cologne, Germany [email protected]
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 [email protected]
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 [email protected]
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
