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88 • "PROTIST—2016
been used as indicators of freshwater quality, they are rarely used in this capacity in marine waters. Here I will summarize the results of a series of studies carried out in Jiaozhou Bay, on the Yellow Sea coast of NE China, in which we investigate the relationships between ciliate communities, both planktonic and periphytic, and certain physico-chemical parameters that varied at different sites within the Bay. In each study, ciliates were identified and enumerated by direct microscopy, and data were analyzed using various statistical packages mainly within PRIMER. A main aim of this investigation was to develop protocols that maximize the efficiency of sampling and analyses of the ciliate communities. Our main findings were: (1) the 8-sampling events per year may be an optimal sampling strategy for planktonic ciliated protozoan seasonal research in marine ecosystems; (2) 90% of the periphytic community could be recovered on 10 microscope slide replicates immersed at one depth for 3 — 21 days; (3) multivariate (step-best-matching) analysis allows a subset of the most reliable indicator species to be identified without losing accuracy of water quality prediction; (4) applying taxonomic efficiency, i.e., identifying to the highest rank without losing critical bioindicator information, revealed that genus-level identification allows for accurate prediction of water quality; (5) efficiencies of sample analyses can be achieved by omitting ubiquitous groups, and using presence/ absence of others rather than abundance data.
SPECIES CLASSIFICATION AND MATING IN FORAMINIFERA
Weiner A.K.M., Tsuchiya M., Toyofuku T., Kitazato H.
JAMSTEC, Japan Agency for Marine Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Kanagawa, Japan [email protected]
Many groups of foraminifera are characterized by the formation of elaborate shells, which provide detailed morphological features, useful for species classification. Since the majority of works focuses on their fossilized shells, a comprehensive morphotaxonomy has been established. Yet, genetic analyses revealed an even higher diversity on the molecular level, hidden within the traditional morphospecies. These cryptic species are marked by large genetic distances and differentiated distribution patterns, implying that cryptic species rather than morphospecies represent the level of species. As a consequence, today we are facing a conflict between the morphological species concept and the interpretation of genetic diversity. The
biological meaning of both is still unclear and the relationship between genetic divergence and the level of species or populations remains uncertain. In order to overcome this conflict, we try to combine aspects of morphological variability, genetic diversity and reproduction to achieve an integrative approach for species delimitation in foraminifera. To this end, we carry out breeding experiments on benthic foraminifera to observe the mating behavior between genetically divergent lineages to detect the level of divergence that corresponds to reproductive isolation. In addition, we plan to observe the mating behavior among genetically homogenous populations to examine the existence of different mating types within a population. The mating system largely influences the generation of genetic variation and contributes to the process of adaptation. Understanding its mechanisms in foraminifera is thus essential to understand the diversification and evolution of the group.
THE EVOLUTION OF MITOCHONDRIAL MEMBRANE CONTACT SITES Wideman J.G.
Department ofBiosciences, University ofExeter, United Kingdom
[email protected] It is commonly accepted that mitochondria evolved from an alpha-proteobacterial endosymbiont to become the major energy producing organelle of the eukaryote cell. Accounts describing the integration of the pre-mitochondrial symbiont into host cell processes often focus on this transfer of the control of energy production from the symbiont to the host. However, mitochondria are more than mere ATP generators and have several physical and functional links to various cell systems. One such link is manifested in the physical and functional link between mitochondria and the endomembrane system in the form of membrane contact sites (MCSs). These MCSs are important for non-vesicular lipid transport between apposed membranes. Recent progress has identified the protein complexes responsible for maintaining MCSs in Saccharomyces cerevisiae. A surprising number of functionally overlapping mitochondrial MCS tethering complexes have been described, but the extent to which MCS tethers are conserved between distant lineages appears to vary. Thus, while being functionally redundant in S. cerevisiae, MCSs appear to have a high degree of evolutionary plasticity in eukaryotes. Taken together, these data suggest that the last eukaryote common ancestor had a mitochondrion highly connected to diverse endomembranes, but over the course of eukaryote
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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
