CC BY
18
64 • "PROTIST—2016
maria.rautian@mail.ru
BACKGROUND. P. bursaria belongs to one of the best studied Ciliate's genus Paramecium. This species diverged basically from other paramecia. They possess symbiotic Chlorella in the cytoplasm. These Chlorella were attributed to three Chlorella species — Ch. vulgaris, Ch. variabilis and Micractinum reisseri according to their phylogeny inferred from ITS1-5.8S-ITS2-5'LSU rDNA sequence and their sensitivity to specific viruses (PBCV). Morphospecies P. bursaria consist of 5 syngens — reproductively isolated intraspecies groups. Previously we have shown that syngens were represented by different branches on phylogenetic trees. The purpose of our investigation was to study phylogeny of P. bursaria and their symbiotic Chlorella using the same set of strains collected in different geographic regions. RESULTS. Gene RuBisCo have been used as molecular marker for Chlorella phylogeny. The tree consists of three separate branches. Diversity in each branch is negligible. Our data support strong correspondence between P. bursaria syngens and branch of Chlorella, while weak correlation between Chlorella type and its geographic location. CONCLUSIONS. According to our results we have concluded that successful symbiosis between P. bursaria ancestor and Chlorella has been established at least three times. The last time it had been happened before syngens R1 and R2 have diverged. We propose the strategy of evolution and geographic dispersion of this symbiotic system. Scientific research was performed at the Center for Culturing Collection ofMicroorganisms and Center for Molecular and Cell Technologies of Research park of St. Petersburg State University. Supported by RFBR grant 13-04-01714.
THE PLASTID GENOME OF POLYTOMA UVELLA IS THE LARGEST KNOWN AMONG NON-PHOTOSYNTHETIC ALGAE Reves-Prieto A.12
1 - Biology Department. University of New Brunswick, Fredericton
2 - Integrated Microbiology Program. Canadian Institute for Advanced Research. areyes@unb.ca
The polyphyletic assembly Polytoma and the species of the genus Polytomella represent different lineages within the Order Chlamydomonadales (Chlorophyta) that lost photosynthesis independently. The Polytomella clade is one of the two known groups of plastid-bearing eukaryotes that have lost completely the plastid genome (ptDNA)
after the loss of photosynthesis. Before the present report it was unknown if the absence of genome in the Polytomella plastids was a shared condition with species of the Polytoma genus. We present here the ptDNA of Polytoma uvella UTEX 964, which is the largest (circa 230 Kb) reported among non-photosynthetic algae. The ptDNA of P. uvella has lost all genes related with the photosynthetic function and its residual coding capacity is similar to ptDNAs from distantly related colorless chlorophytes, such as the pathogens Prototheca and Helicosporidium. The gene repertoire of the P. uvella ptDNA comprises mostly transcription and translation players and just few conserved proteins (e.g., FtsH-like, Ycf1-like and ClpP). Regardless of the substantial gene loss, the P. uvella ptDNA shows evidence of expansion due to the accumulation ofintergenic short repeated sequences (average length of 2.9 Kb). It is plausible that recombination-based DNA repair mechanisms are responsible of the genomic expansion of the P. uvella ptDNA.
SELECTION AND CHARACTERIZATION OF SINGLE CHAIN VARIABLE FRAGMENT (SCFV) ANTIBODIES AGAINST PNEUMOCYSTIS JIROVECII FROM PHAGE DISPLAY LIBRARIES
Ribeiro Marta, 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 omatos@ihmt.unl.pt
Pneumocystis pneumonia (PcP) is an infectious disease caused by Pneumocystisjirovecii, an atypical fungus. PcP remains a major cause of respiratory illness among immunosuppressed patients. Current PcP diagnosis is based on the detection of P. jirovecii in respiratory specimens, obtained by invasive methods such as bronchoalveolar lavage, followed by cytochemical staining, immunofluorescent staining with monoclonal antibodies (IF/Mab) or PCR. Therefore, the possibility of an early diagnostic method allowing the use of biological specimens obtained non-invasively, is highly desirable. Rapid diagnostic tests (RDTs) using gold nanoparticles (AuNPs) allow a more sensitive, fast and cheap diagnosis, to be used in developing countries. The goal of this work is to develop an immunochromatographic RDT for the detection of P. jirovecii in non-invasive specimens like serum. In this test, spherical AuNPs are conjugated with a multi-epitope synthetic recombinant antigen (msr) which will allow the detection of circulating anti-P.
