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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
