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Protistology ■ 47
D. Méndez-Sánchez. To IRCN-BC for the grant to D. Méndez-Sánchez for a short stay at Laboratory of Protozoology OUC. Special thanks to Miss Chundi Wang and Mr. Zhishuai Qu (Laboratory of Protozoology, OUC) for their technical assistance in the molecular procedures and staining protocols respectively. We thankful to people from Tziscao, Chiapas, who allowed us recollected samples.
DIVERSITY OF THECAMOEBID AMOEBAE (AMOEBOZOA: DISCOSEA: THECAMOE-BIDAE) Mezentsev Y.S.
Saint-Peterburg State University [email protected]
Amoebae of the family Thecamoebidae are widely distributed in the different environments: salt and fresh water and soil. These protists are relatively easy to isolate and cultivate. They are relatively easy determining to genus, or even to species, thus representing a convenient object for many kinds of studies. The frequency of occurrence of species is very different: there are rather common ones like Thecamoeba quadrilineata, T. similis and T. orbis as well as numerous species known from few findings or never re- isolated since initial description. Many of these species were studied only at the light-microscopic level and require investigation with modern methods, including electron microscopy and molecular studies (this especially concerns the genus Thecamoeba and genera ofunclear systematic position like Pseudothecamoeba and Thecochaos). Our studies show that "hotspot" of Thecamoeba diversity is terrestrial habitats — soil, grass, dry leaves and surface of trees. During our studies we isolated 20 strains of Thecamoeba; some were identified as known species (Thecamoeba aesculea, T. similis, T. quadrilineata and T. terrícola) and 6 strains, which represent new species of the genus Thecamoeba. We have found two new strains of amoebae belonging to the genus Sappinia. In contrast, amoebae of the genus Stenamoeba were never found in terrestrial samples. Our data shows that species diversity of thecamoebid amoebae remains considerably underexplored.
Supported with Russian Science Foundation grant 14-14-00474.
ESTABLISHING CRYPTOSPORIDIUM AS A
MODEL FOR STUDYING THE BIOLOGY
AND EVOLUTION OF APICOMPLEXANS
AND UNIQUE ORGANELLES
Miller C., Brown I., Howard M., Michaelis M.,
Tsaousis A.
University of Kent, UK
Cryptosporidium spp. display a number of unusual traits, distinct from other apicomplexans; notably a smaller genome and the absence of an essential organelle, the apicoplast. There are also intra-species differences, such as a reduced mitochondrion in C. parvum and C. hominis, in size and functions. Studying these organisms holds great potential for our understanding of how the apicomplexans diverged. Studies of Cryptosporidium are inhibited by a limited selection of in-vitro culturing systems, with short lifespans and production volumes. Using a novel cell line for propagation we have seen a significant increase in parasite production volume as well as a longer lifespan, which have enabled the development of many new techniques for studying Cryptosporidium and its cell biology and biochemistry. Amongst these new techniques is the development of NMR and Mass spectrometry protocols, which have been optimised to examine the metabolic flux of the parasite, as well as investigating the role of the mitosome. We have also acquired many electron microscopy (EM) images ofthe parasite during its life cycle, identifying details of structures at levels previously unseen in the literature. Furthermore, using Immuno-EM we have shown the first experimental evidence of the function of the mitosome in C. parvum, with the localisation of iron sulphur cluster biosynthesis proteins.
DIVERSITY AND TEMPORAL DYNAMICS OF CRYPTOMYCOTA AND APHELIDA, TWO OVERLOOKED GROUPS OF PARASITES IN FRESHWATER ECOSYSTEMS Moreira D.1, Jardillier L.1, Bertolino P.1, Karpov S.A.2, Lopez-Garcia P.1
1 - Ecologie Systématique Evolution, CNRS - University Paris-Sud, Orsay, France
2 - Zoological Institute, Russian Academy ofSciences, St. Petersburg, Russian Federation [email protected]
Basal-branching fungi, especially chytrids, are important heterotrophic members of aquatic microbial food chains, especially in freshwater. More recently, two additional groups very distantly related to fungi, Cryptomycota (or Rozellomycota) and Aphelida, have also been found to be ubiquitous members of freshwater microbial communities. Together with the Microsporidia, they form the recently described superphylum Opisthosporidia. All known opisthosporidian species are parasites of very diverse eukaryotic hosts. Remarkably, both cryptomycetes and aphelids are able to feed by phagotrophy, a chief difference with microsporidia
