CC BY
23
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
sifokin@mail.ru
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 zoltan@paru.cas.cz
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
20 • "PROTIST—2016
detail the ultrastructure of Vitrella brassicaformis, concentrating on the apical region of the flagellar stage. A previous work described a lifestage, surrounded by roughly structured matter of the containing sporangium, with an intracytoplasmic axoneme structure suggested to develop into mature flagellum. Here we describe a novel stage with cells developing a flagellum extracellularly. These cells concurrently bud off the center of the sporangium, surrounded by smooth matter, in a process reminiscent of ectomerogony as seen in Eimeria. We suggest that the former process generates gamete-like flagellate progeny, while the latter process yields zooflagellates. We failed to find apical structure similar to the pseudoconoid in C. velia. We propose that the common ancestor of Apicomplexa and "chrompodellids" exhibited a complex lifecycle, while extant descendants underwent gradual reduction of these processes as forced by their environment. Acknowledgement: The authors would like to thank the Czech Science Foundation (JK, HJE, MO) and the Czech Academy of Sciences (ZF) for funding.
DIFFICULTIES IN ASSESSING THE GLOBAL DISTRIBUTION OF A MODEL ORGANISM - THE BIOGEOGRAPHY OF FAVELLA PANA-MENSIS (ALVEOLATA, CILIOPHORA) Ganser M., Agatha S.
University ofSalzburg, Dept. Ecology and Evolution maximilian.ganser@stud.sbg.ac.at Accurate circumscriptions and determinations of species are essential for biodiversity and biogeo-graphy assessments; traditionally, the morpho-species concept was employed. Tintinnid ciliates are exceptional as - in contrast to the vast majority of ciliates - the whole taxonomy and classification of the more than one thousand marine planktonic species are almost exclusively based on characteristics of their vase-shaped loricae (houses). Because it is relatively easy to collect, preserve, examine, and classify, the lorica has allowed the accumulation of invaluable diversity and distribution data for more than two centuries. However, lorica-based taxonomy is problematic because of the high intraspecific variability and interspecific similarity of the loricae; so, the species limitations are currently unknown. Besides misidentifications, the diversity and geographic ranges perceived are especially affected by revisionary taxonomic treatises differing in their species circumscriptions from the original descriptions due to synonymisation (range of morphologic features became wider) and splitting (range of features became smaller) of species. Despite these difficulties, Montagnes (2013)
suggested the tintinnid genus Favella as a model for planktonic ciliates. In the present study on the biogeography of Favella panamensis, the species records from about one hundred of taxonomical and ecological studies were classified according to their quality: (i) reliable records from the type and neo-type localities mentioned in the original description and authoritative redescription; (ii) more or less reliable records supported by descriptions, measurements, and/or illustrations that fit the original description and redescription; and (iii) unsubstantiated records (mostly simple species lists) based on uncertain identifications. The comparison of the data provided by substantiated records with the original description revealed false positive and negative identifications. Since currently the species circumscriptions are uncertain, the usage of the original descriptions or authoritative redescriptions for the identification of tintinnid ciliates is strongly recommended. Only later, when the cell features and barcodes of the morphotypes are known, we might be able to perform justified synonymisations. References. Montagnes (2013): Ecophysiology and behavior of tintinnids. In: Dolan J.R., Montagnes D.J.S., Agatha S., Coats W.D. & Stoecker D.K. (2013): The Biology and Ecology of Tintinnid Ciliates: Models for Marine Plankton. Wiley-Blackwell: 85-121.
THE BEGINNING: INFERENCE OF THE TINTINNID ANCESTOR'S MORPHOLOGY (ALVEOLATA, SPIROTRICHA, TINTINNINA) Ganser M., Agatha S.
University ofSalzburg, Dept. Ecology and Evolution maximilian.ganser@stud.sbg.ac.at Tintinnids are a speciose group of ciliates, whose taxonomy and systematics are almost exclusively based on lorica features. Physico-chemical factors and the cell cycle, however, influence these taxonomic characters, resulting in an artificial classification with several non-monophyletic groupings. The sparse cytological data and the more comprehensive molecular phylogenies indicate that the tintinnids developed in the marine environment and entered freshwater several times independently. The tintinnidiid genera Tintinnidium and Membranicola are typical representatives of the limnetic plankton and are characterized by a simple somatic ciliary pattern and a strong synapomorphy, namely, the two de-novo-originating ventral organelles. The family is sister to the remaining, mainly marine species. As yet, only a single member of the genus Tintinnidium, T. mucicola, is known to occur in marine and brackish coastal waters, suggesting that it might provide clues pivotal to
