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Protistology ■ 89
divergence ancient MCS tethers were lost while others were gained in a lineage-specific manner.
UNRAVELLING THE DIVERSITY OF DIPLO-NEMIDS BY CULTURE-BASED TAXONO-MIC STUDY
Yabuki A.1, Kusaka C.1, Votypka J.23, Horak A.3, Lukes J.3, Fujikura K.1
1 - Department ofMarine Biodiversity Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Japan
2 - Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
3 - Biology Centre, Institute of Parasitology, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, Ceske Budejovice (Budweis), Czech Republic [email protected]
Diplonemids (Diplonemida) belong to the phylum Euglenozoa and they are unicellular flagellates that are free-living or parasitize algae and invertebrates. Although Diplonemida included for decades only the genera Diplonema and Rhynchopus yet, the genus Hemistasia was recently transferred to Diplonemida based on the phylogenetic analysis. Hemistasia phaeocysticola is a representative of a large environmental clade that remained to be identified in Diplonemida. Members of this environmental clade have attracted attention not only from taxonomic/phylogenetic perspective, but also due to highly unusual RNA processing in their mitochondria, which is reminiscent oftrans-splicing and editing, so far reported only from them. Hence, the studies focusing on H. phaeocysticola and the other members of this environmental clade may expand our knowledge about the structural diversity and evolutionary history ofunusual structural genes in this protist group. We have isolated new marine diplonemids and keep some of them in culture. In the present study, we report their morphology and phylogenetic positions in Diplonemida: some cultures branch within the clade that is composed of environmental sequences and H. phaeocysticola, while others are also shown to be novel lineages in the clade of Diplonema and Rhynchopus. Our findings significantly expand the known diversity of diplonemids and it is also suggested that the classification system under Diplonemida should be revised: the establishment ofa novel family is possibly needed for the members ofthe environmental clade.
RED ALGAL PHYLOGENYAND EVOLUTION BASED ON MITOCHONDRIAL GENOME Yang E.C.1, Lee J.2, Yoon H.S.2 1 - Korea Institute of Ocean Science & Technology,
Ansan 15627, Korea
2 - Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Korea [email protected]
The Florideophyceae (5 subclasses and 31 orders) and Bangiophyceae (1 subclass and 1 order) distribute in both marine and freshwater habitats, and cover the most described red algal diversity, ca. 7,100 species (98% of Rhodophyta). The monophyly those two classes and relationships among subclasses were well-supported in many phylogenetic analyses, however, interordinal phylogeny remain largely unknown in the subclass Rhodymeniophycidae. In order to resolve ordinal relationships and evolution of the subclass, we have determined 11 mitochondrial genomes (mtDNA) from representative species and compared with published data. Concatenated phylogeny based on 37 mtDNA (6,345 aminoi acid data) of red algae showed stronger support among order level than previous studies. The mtDNA synteny comparison showed 47 events of gene evolution (indel and rearrangement) among Bangiophyceae, Hiden-brandiophycidae, Nemaliophycidae, Corallino-phycidae, Ahnfeltiophycidae, and Rhodymenio-phycidae. We demonstrate that all rhodymeniophy-cidan mtDNA have conserved architectures with little variation of contents. Based on the best phylogeny, we inferred the ancestral mtDNA content, evolution and reduction of protein coding genes in red algae.
NEW MITOCHONDRIAL GENOMES AND MOLECULAR MARKERS FOR THE COASTAL DIATOMS OF KOREA Yang E.C., Noh J.H.
Korea Institute ofOcean Science & Technology, Ansan
15627, Korea
The Bacillariophyceae is the largest class of the stramenopiles (ca. 11,200 species), and one of the most important and abundant primary producers of the aquatic ecosystem. Diverse diatoms are occurred in inter-tidal mudflats of the west coast of Korea, the Yellow Sea. In spite of ecological importance ofthe phytoplankton community, there are a little number of molecular markers have been developed, such as nuclear encoded 18S rRNA (SSU) and plastid encoded rbcL. In present study, we determined two new mitochondrial genome (mtDNA) of common tube-dwelling diatoms, Berkeleya fennica TA424 (GenBank accession NC_026126, 35.509 bp) and Navicula ramosissima TA439 (48,652 bp) isolated from the Taean mudflat (36°44'14.79"N 126°10'41.89"E), and one mtDNA
