CC BY
31
Protistology ■ 57
1 - Department of Invertebrate Zoology, Faculty of Biology, Saint-Petersburg State University, Uni-versitetskaya emb. 7/9, St. Petersburg, 199034, Russian Federation
2 - Department of Invertebrate Zoology, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory 1—12, Moscow, 119234, Russian Federation
3 - Belozersky Institutefor Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russian Federation [email protected]
Agamococcidians (Agamococcidiorida Levine, 1979) represent an enigmatic group ofApicomplexa. The life cycle of these parasites is characterised by presence of oocysts with sporocysts (similar to coccidian), sporozoites and trophozoites, and by absence of merogony and gamogony. This group combines two families Rhytidocystidae Levine, 1979, parasites of polychaetes, and Gemmocystidae Upton & Peters, 1986, parasites of stony corals. The phylogenetic position of these organisms is still unclear. Previous phylogenetic studies brought agamococcidians together with gregarines and cryptosporidians (Leander, Ramey, 2006; Rueckert, Leander, 2009; Kristmundsson et al., 2011; Cavalier-Smith, 2014). In contrast, morphological data (oocysts with sporocysts and nonmotile trophozoites located within host epithelial tissues) indicate a relationship of agamococcidians with coccidians. We isolated two putative new species of Rhytidocystis from polychaetes Pectinaria hyperborea and Ophelia limacina collected in the Keret Archipelago of the White Sea, Russia. The SSU rDNA sequences obtained from these new parasites clustered strongly with Rhytidocystis cyamus and R. polygordiae within the rhytidocystid clade. Phylogenies inferred from these sequences demonstrate a close relationship between rhytidocystids and marine coccidians. Interestingly, some coccidians closely related to rhytidocystids, such as Margolisiella islandica or Aggregata sp., have all three types of reproduction found among apicomplexans: spo-rogony, merogony and gamogony in their life cycles. Thus, our molecular data agree with known morphological data. We discuss the phylogenetic position and perspectives of further investigations of agamococcidians for more deep understanding of Apicomplexa evolution. Supported by St. Petersburg State University projects (1.42.1493.2015, 1.42.1099.2016).
CAPSASPORA OWCZARZAKIAS A UNICELLULAR MODEL TO STUDY CO-OPTION OF THE ANCESTRAL INTEGRIN ADHESOME Parra-Acero H.1, Harcet M.12, Pérez-Posada A.1, Brown N.H.3, Ruiz-Trillo I.145
1 - Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Catalonia, Spain
2 - Division of molecular biology, Ruder Boskovic Institute, Bijenicka cesta 54, 10 000 Zagreb, Croatia
3 - Dept of Physiology, Development and Neuro-science,University of Cambridge,Downing St, Cambridge CB2 3DY, UK
4 - Departamentde Genética, Universitatde Barcelona, Barcelona, Catalonia, Spain
5 - Institució Catalana de Recerca i Estudis Avangats (ICREA), Barcelona, Catalonia, Spain [email protected]
Adhesion systems and signaling networks are both essential in multicellular organisms. Some elements of the adhesion and signaling pathways of metazoans, such as proteins from the integrin adhesome are conserved in their closest unicellular relatives. This means these proteins already existed in the unicellular ancestor of metazoans and that they were co-opted for a multicellular lifestyle. To understand how the integrin adhesome was co-opted at the onset of Metazoa, we aim to unravel its function in a close unicellular relative of animals, the filasterean Capsaspora owczarzaki. This protist is the closest unicellular relative to metazoans that contains in its genome the basic core ofproteins that constitutes the integrin adhesome. The expression of these proteins is upregulated during the aggregative stage in culture conditions. In order to understand its role, we are developing some molecular and genetic tools, such as immunostaining, transfection, and CRISPR/cas9. We will discuss preliminary data on the localization of several cytoskeletal and adhesion proteins of the integrin adhesome in C. owczarzaki, obtained by overexpression and by immunostaining with antibodies raised against our proteins of interest. We will also discuss the development of CRISPR system in this organism with the aim to develop a complete model system to analyze the origin of animals.
ORAL PROTISTS: IMPORTANCE TO CANINE
PERIODONTAL DISEASE
Patel N.12, Holcombe L.1, Andrew P.2
1 - Mars Petcare UK
2 - University of Leicester [email protected]
