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48 • "PROTIST—2016
and true fungi, all of them osmotrophic. Despite the ubiquity of cryptomycetes and aphelids in diverse environments, little is known about their abundance and temporal dynamics. We have carried out a 2-year monthly survey of eukaryotic plankton diversity in five contrasted freshwater ecosystems (one brook, one small lake, and three shallow ponds) using massive 18S rRNA gene amplicon sequencing to compare cryptomycetes and aphelids with the much better-known chytrids. OTU analysis reveal that cryptomycetes and aphelids are less diverse than chytrids (556, 313, and 1274 OTUs, respectively) although in some moments cryptomycete+aphelid combined OTU number can exceed that of chytrids. Cryptomycetes show stable low numbers of sequences (<1% of total sequences) all along the year, in contrast with aphelids, which exhibit a more heterogeneous dynamics with recurrent abundance peaks in early autumn (>4% of sequences), when they become even more abundant than chytrids. These results suggest that cryptomycetes and aphelids are important overlooked members of freshwater ecosystems that most likely control other eukaryotic populations through their parasitic activity.
APPLICATION OF RECOMBINANT ANTIGENS FOR THE SERODIAGNOSIS OF TOXOPLASMOSIS
Mota Catia, Cardoso Fernando, Matos Olga Medical Parasitology Unit, Group of Opportunistic Protozoa/HIVand Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Portugal [email protected]
Toxoplasma gondii is an opportunistic apicomplexan protozoon that can cause devastating disease in immunosuppressed patients and congenital infection. The diagnosis of toxoplasmosis is usually done by observing the parasite in biological samples or by the detection of specific IgM and IgG against T. gondii antigens in the patient's serum. The improvement of toxoplasmosis diagnostic techniques and the differentiation between the infection stages can be achieved using recombinant antigen. This study aims to use micronemal protein MIC3 (elicits a strong specific host immune response) recombinant antigens in the serodiagnosis of toxoplasmosis. Toxoplasma RNA was isolated using the Tri-Reagent method and a PCR was performed using primers for MIC3 nucleotide sequence. The bands corresponding in size to the recombinant plasmid were purified and cloned into the cloning vector pLATE 28 and in the expression vector
pLATE 31. An expression study was performed in different E. coli BL21 (DE3) strains: Star, XJB, RIPL and PlysS. These strains were transformed with the recombinant vector pLATE 31 in order to obtain clones. Three random clones were therefore selected and induced with IPTG. The result ofthe induction was observed on a SDS-PAGE electrophoresis. The recombinant protein was purified by high-affinity chromatography with immobilized nickel ions and subsequently analyzed by ELISA, SDS-PAGE electrophoresis and quantified by Nanodrop 1000. Preliminary results show that the best E. coli strains for expression are BL21 (DE3) RIPL and BL21 (DE3) PlysS, based on SDS-PAGE analysis. The optimization of the ELISA assay is in progress. Acknowledgments: Supported partially by FCT ref:VIH/SAU/0019/2011.
THE RAPUNZEL TINTINNID - REDESCRIPTION OF TINTINNOPSIS SUBACUTA JORGENSEN, 1899 (ALVEOLATA, CILIO-PHORA, SPIROTRICHA) Muhlthaler A., Kagerer M., Agatha S. Dept. Ecology and Evolution, University ofSalzburg, Salzburg, Austria [email protected]
Tintinnids contribute distinctly to the microbial biomass in the marine plankton. Since the species have specific requirements concerning physico-chemical conditions and food items, reliable identification is indispensable for assessing their role in the food web. About one thousand extant tintinnid species are known, whose descriptions are exclusively based on the features of their loricae (houses); merely in about 30 species, cell characteristics have been studied. Since lorica shape and size are affected by environmental conditions and might show a polymorphism in the cell cycle, the tintinnid classification is artificial. Investigations of the cell, especially of the ciliary pattern and nuclear apparatus (generative micronuclei and somatic macronucleus nodules) are, however, supposed to provide features for a natural classification; these characters are revealed by protargol (silver proteinate) staining. Tintinnopsis subacuta was collected from surface waters of the Indiana River at the Atlantic coast of Florida (USA) and stained with protargol. Cell and lorica morphology were investigated under a compound microscope at up to 1250* magnification. The lorica is 55-119 ^m, on average 79 ^m long and consists of a cylindroidal collar about 34 ^m across and a subspherical bowl about 45 ^m wide. The lorica wall has agglutinated mainly mineral particles. The contracted cell
