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92 • "PROTIST—2016
closely related species and are proper markers for ciliates barcoding.
THE INTRICATE EVOLUTIONARY HISTORY
OF RhoBTB PROTEINS
Zihala D.1, Klimes V.1, Rivero F.2, Elias M.1
1 - University ofOstrava, Faculty ofScience, Department of Biology and Ecology, Chittussiho 10, 710 00 Ostrava, Czech Republic
2 - Centre forCardiovascular and Metabolic Research, The Hull York Medical School and Department of Biological Sciences, University of Hull, Cottingham Road, Hull HU6 7RX, UK z.ihaladavid@gmail.com
The Rho family is one of the major subgroups of the huge superfamily of Ras-like GTPases. Rho proteins are known primarily as regulators ofvarious pathways that are connected to the actin cytoskele-ton (cell movement, polarization, morphogenesis etc.). These proteins usually contain only the Rho-type GTPase domain, but some of them possess also a tandem of two so-called BTB domains and are called RhoBTB proteins. The BTB domain is a protein-protein interaction domain and is often a part of proteins that are connected to protein ubiquitination through Cullin3-dependend E3 ligases. Proteins with the domain architecture characteristic for RhoBTB proteins have been reported only from metazoans and dictiosteliid slime moulds, but this distribution was deduced from a phylognetically very limited survey. We have utilized the currently available wealth of genomic and transcritpomic data from diverse eukaryotes, including a wide coverage of protist taxa, and found out that RhoBTB proteins occur in many additional eukaryotic lineages. Although scattered, the phyletic pattern of RhoBTB genes is compatible with a hypothesis that a primordial RhoBTB gene was present already in the last eukaryotic common ancestor. Interestingly, RhoBTB proteins from some taxa (Amoebozoa, Apusomonadida, and Cryptomonadida) proved to possess a RING/U-box domain inserted into the first BTB domain. RING and U-box are related domains that constitute a class of E3 enzymes, so our findings further support the idea that RhoBTB3 proteins ancestrally served as components of ubiquitin-mediated regulation. These and other findings of our evolutionary analyses of RhoBTB proteins will be presented and discussed.
THE STATE OF ART IN THE TAXONOMY OF
"HELIOZOA"
Zlatogursky V.V.
Department of Invertebrate Zoology, Faculty of
Biology, Saint-Petersburg State University v.zlatogursky@gmail.com
"Heliozoa" is a former taxon of spherical axopodial protists. These organisms, being outwardly similar have revealed to be not necessarily related. Some of lineages are now placed into the proper "supergroups", while many deviant forms still remain "orphans". The most diverse group — the centrohelids — recently was placed in Haptista along with haptophytes and their internal taxonomy also was considerably revised showing interesting examples of parallel evolution. But in comparison to other groups with a developed taxonomy "Heliozoa" still seem to be undeservingly neglected. Many taxa of flagellates, ciliates and in a less degree of amoebae get much more attention, while heliozoan taxonomy suffer from the lack of skilled taxonomists. The great amount of their diversity is likely to be unknown. The heliozoans require closer attention, being ubiquitous in freshwater, marine (both planktonic and benthic) and soil environments, important consumers of bacteria, protists and even micrometazoans. But the taxonomic impediment currently prevents them from being incorporated into ecological and biogeographic studies. Many heliozoans, especially centrohelids, are easy to maintain in the culture, have a rich morphology and potentially can serve a good model for addressing many of fundamental questions of protistology, including a species problem, the endemism vs ubiquity dilemma and the evolution of cell coverings. Many of them can be indicators ofwater quality and should be included to biodiversity indexes. But first of all, their taxonomy need to be evaluated and the main proportion of species should be described on the modern level. Study support: RFBR grants 15-04-18101_a, 15-29-02749-ofi_m.
THE RELIABILITY OF PROTOZOANS AS INDICATORS OF AQUATIC ECOSYSTEM HEALTH Zolotarev V.A.
I.D. Papanin Institute for biology of inland waters Russian Academy of Sciences (IBIW RAS) forest753@gmail.com
Metapopulations of microbial organisms occur worldwide wherever their required habitats are realised. This is a consequence of ubiquitous dispersal driven by huge population sizes, and the consequently low probability of local extinction (Finlay, 2002). Microorganisms should be used in biomonitoring for several compelling reasons. (1) A cosmopolitan distribution facilitates comparisons of test results in geographically different regions. (2) Problems of scale are diminished. (3) Replicability
