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Protistology ■ 75
time, mostly due to: (i) its peculiar habitat, (ii) the presence of cytoplasmic bacterial endosymbionts, (iii) a complex life-cycle with unusual morphologies, and (iv) a presumably mutualistic association with its animal host. Moreover, several lines of evidence suggest that the renal sac of an individual tunicate host harbors a complex community of diverse Nephromyces lineages: the multiple-infection hypothesis. We decided to further investigate this hypothesis and elucidate the phylogenetic position of Nephromyces within Apicomplexa by using deep sequencing of renal sacs in order to better understand the developmental dynamics of this symbiosis. Our initial analyses revealed the presence of eleven apicoplast genomes in one single renal sac. Surprisingly, there was considerable sequence divergence among the apicoplast genomes, although their gene content and order was highly conserved. We then used the phylogenetic information contained within 27 apicoplast proteins to infer Nephromyces' phylogenetic placement within Apicomplexa. These preliminary results support the idea that molgulid renal sacs are complex ecosystems inhabited by a diverse community of different Nephromyces lineages. In addition, we clarified the phylogenetic position of Nephromyces as sister to 'core' apicomplexans (Hematozoa+Coccidia), and highlighted the significant intra-clade divergence among these apicoplasts. Future efforts will focus on elucidating the metabolic contribution of each partner to the dynamics of this complex symbiotic system.
PHYLOGENY, DIVERSITY AND EVOLUTION OF AMOEBOZOA: NEW FINDINGS AND NEW PROBLEMS Smirnov Alexey
DepartmentofInvertebrate Zoology, Faculty ofBiology, St. Petersburg State University, St. Petersburg, Russia [email protected]
Amoebozoa is a major group of protists that unifies naked and testate lobose amoebae, varioseans, slime molds and pelobionts. The diversity and systematics of some groups, like slime molds and testate amoebae, possessing stable morphological characters - fruiting bodies or tests - was relatively well studied, also some evolutionary traits derived from morphology were further disproved by molecular phylogeny. In contrast, naked amoeboid protists with no constant shape remain relatively poorly known, molecular phylogeny nearly entirely rearranged earlier views on their evolutionary relationships. SSU-based phylogeny shows that naked amoebae belong to three different amoebozoan lineages and the most of organisms formerly known
as protostelids are dispersed among different groups. The basic finding was the split of naked amoebae in two lineages, named Tubulinea and Discosea and the fact that testate lobose amoebae form just a single branch within Tubulinea. The basal branching of Amoebozoa could not be properly resolved with SSU trees. Multigene data help to clarify many essential questions, e.g. they show that Discosea does not appear to be a monophyletic group. However, with the increment of taxon sampling multigene trees seem to experience the same problems and artifacts as SSU trees did. Recent studies of extreme and exotic habitats revealed a number of new species, especially among the smallest amoebozoans, some were found to be key taxa for rooting Amoebozoan tree. Genbank contains numerous unnamed sequences belonging to new amoebozoan lineages. This indicates that environmental diversity of Amoebozoa is still in much unexplored. Supported with RSF grant 14-14-00474.
TRANSCRIPTOME ANALYSIS OF NAEGLE-RIA FOWLERICYSTS AND TROPHOZOTIES BY NEXT-GENERATION SEQUECING Sohn Hae-Jin1, Seong Gi-Sang1, Kang Heekyoung1, Jung Suk-Yul2, Shin Ho-Joon1, Kim Jong-Hyun3
1 - DepartmentofMicrobiology, Ajou University School of Medicine, Republic of Korea
2 - Department of Biomedical Laboratory Science, Molecular Diagnostics Research Institute, Namseoul University, Republic of Korea
3 - Institute ofAnimalMedicine, College of Veterinary Medicine, GyeongsangNational University, Republic of Korea
Naegleria fowleri, ubiquitous pathogenic amoeba causing the fatal primary amoebic meningo-encephalitis (PAM) in experimental animal and humans, is predominantly living in the ponds, lakes, rivers and swimming pools. N. fowelri trophozoites are encysted under unfavorable conditions such as cold temperature, starvation and desiccation. However, the information in differential expression genes between cysts and trophozoites of N. fowelri is very limited. In this study, RNA-sequencing libraries from N. fowleri cysts and trophozoites were investigated by Next-Generation Sequencing (NGS) analysis. In the NGS database, the assembly procedure resulted in mean full length of 11, 254 nucleotides in total 42,220 transcript contigs and 37.21 % of C+G contents. RNA sequencing indicated that upregulated 143 genes in cysts showed 2 folds expression in comparison with trophozoites and 163 genes were downregulated. These genes were found to participate in Kyoto Encyclopedia
