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38 • "PROTIST—2016
Arcellinid testate amoebae are a diverse group of terrestrial and freshwater microbial Eukaryotes. Described by naturalists since the eighteenth century, Arcellinids are frequently used in biomonitoring and paleo-ecological reconstruction of past climates. They are supposed to include the oldest undisputed eukaryotic fossils, which vests them with a particular importance in the study of basal nodes of eukaryotic tree. However, difficulties in culturing these organisms as well as in the application of molecular biology protocols have limited the study oftheir diversity and evolutionary history. Our aim in this study was to investigate arcellinid (Amoebozoa, Tubulinea) diversity, and to recon-struct a solid and precise phylogeny combining comprehensive taxon sampling, multiple genes and detailed morphological characterisation. We obtained transcriptomes for twenty-one testate amoeba species, for most of which no molecular data was yet available. Our phylogenetic reconstruction of Arcellinids is based on the combination of morphological data and molecular data on about 350 genes and 100 000 amino acid positions.
HETEROTROPHIC FLAGELLATES IN THE WATER COLUMN AND BOTTOM SEDIMENTS IN THE RYBINSK RESERVOIR Kosolapova N.G., Kopylov A.I., Kosolapov D.B. Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Yaroslavl obl, 152742 Russia [email protected]
A total of 56 heterotrophic flagellates (HNF) from 15 large taxa were identified in water and bottom sediments of the large floodplain mesoeutrophic Rybinsk Reservoir during the summer period. Among them 35 species were detected in plankton and 45 species were found in benthos. Twenty-four species of HNF were common for these two habitats that constituted 44% of their composition. Ten species were recorded only in plankton and 20 species were recorded only in benthos. The orders Chrysomonadida, Euglenida and Cercomonadida differed, to a greater extent, in the species composition in water and bottom sediments. Most of the species of heterotrophic flagellates which were found in the Rybinsk Reservoir were bacteriotrophs. Three predatory species were also found. The abundance and biomass of HNF in the water column averaged 991 ± 326 cells/mL and 41.4 ± 14.1 mg/m3, respectively in the water column and (236 ± 61) x 103 cells/mL and 10.7 ± 4.0 pg/mL, respectively in bottom sediments. The average
values of the abundance and biomass of benthic heterotrophic flagellates were 238 and 259 times, respectively higher than in plankton. The biomass of flagellates constituted on average 11.2% of the bacterial biomass in the water column and only 0.8% in bottom sediments. The estimation of the role of flagellates in the consumption of the bacterial production demonstrated that HNFs were an important factor which regulated the bacterioplankton development grazing on average 32.3% ofits daily production whereas their effect on bacteriobenthos was insignificant as they consumed only 2.0% of its production. The moderate positive correlation (r = 0.33) and (r = 0.52), respectively was found between the abundance and biomass of bacteria both in plankton and benthos.
MINIONS OF GREAT CTHULHU AWAKENING - A NEW INSIGHT INTO THE DIVERSITY OF PARABASALID SYMBIONTS OF COCKROACHES
Kotyk Michael, Varadinova Zuzana, Cepicka Ivan Department ofZoology, Charles University in Prague, Vinicna 7, 128 44 Prague 2, Czech Republic [email protected].
Parabasalian symbiots of xylophagous cockroaches from families Cryptocercidae and Isoptera (termites) have been attracting the interest of biologists for several decades; they often possess large, complex, and visually attractive cells and are of great ecological significance. Phylogenetic analyses showed that the complex forms of parabasalians (=hypermastigotes) have arisen several times independently. On the other hand, only a little attention has been paid to endosymbionts of "normal" cockroaches, although these insects show a great diversity in morphology and lifestyles. We have examined the intestines of 250 cockroaches belonging to 100 species and 20 subfamilies (out of 33), established 50 stable cultures of trichomonads, sequenced their SSU rRNA gene, and studied the morphology of some of them. Approximately one half of the obtained trichomonads formed a considerably diversified clade that contained the recently discovered hypermastigote Cthulhu with approximately 20 flagella and trichomonad genera Hexamastix and Cthylla with 6 flagella. By contrast, our strains have cells equipped with three or four. Thus, Cthulhu and Cthylla are not orphans anymore, but are surrounded by a cloud of lesser trichomonads. Most ofthe remaining strains belong to the understudied genus Hypotrichomonas, where they represent several novel species.
