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10 • "PROTIST—2016
During this work we developed pipeline, based on publically available bioinformatics tools and our own scripts written in Python for transcriptome assembly and annotation. We have found 300 groups ofgenes, which not found outside Amoebozoa or were highly derived within this group of protists. Among them we selected 15 groups of genes with low level of paralogy and performed phylogenetic analysis and primers construction. These genes are promising DNA barcodes for studies of environmental diversity of Amoebozoa. Supported with MK-4853.2015.4 President grant, RFBR 16-34-60111 and SPSU grant 1.38.251.2014.
BURIED BUT NOT DEAD: INSIGHTS INTO THE DIVERSITY, PHYSIOLOGY, FUNCTIONS AND ECOLOGICAL ROLES OF DEEP SUBSEAFLOOR FUNGI USING AN INTEGRATED APPROACH
Burgaud G.1, Rédou V.1, Pachiadaki M.G23, Navarri M.1, Fleury Y.1, Barbier G.1, Edgcomb V.P.2
1 - Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle de Brest Iroise, 29280Plouzané, France
2 - Woods Hole Oceanographic Institution, Department ofGeology and Geophysics, Woods Hole, Massachusetts, United States of America
3 - Bigelow Laboratories, East Boothbay, Maine, USA [email protected]
Bacteria and Archaea are the most commonly studied microorganisms in the marine environment, and habitats such as deep subseafloor ecosystems are no exception. However, recent studies strongly support the idea that deep subseafloor microbial communities include Fungi, which seem to dominate those micro-eukaryotic communities. Using sediment samples from the IODP Expedition 317 as a model, our aims were (i) to better understand the diversity, physiology and functions of deep subseafloor fungi and (ii) to provide clues about how they interact with other microbial populations in those communities. Using a record depth sediment core, fungal molecu-lar signatures and fungal cultures were obtained from samples as deep as 1740mbsf (Rédou et al. 2014) and 1884mbsf (Rédou et al. 2015), respectively. In spite of the fact that those complementary approaches revealed low diversity of higher fungal lineages, DNA and rRNA signatures as well as almost 200 cultured isolates provide direct evidence that fungi persist in this challenging habitat. Consistent with this idea, physiological analyses indicate some deep subseafloor fungal isolates appear well-adapted to in situ conditions.
Metatranscriptome analysis provided an examination of the functional repertoire of deep subseafloor fungi. Gene expression was assigned to metabolic and biosynthetic processes, responses to stress, cell and membrane functions, conidiogenesis and biosynthesis of secondary metabolites (Pachiadaki et al., in revision). These results all provide further support for the notion offungal presence and activity in the deep subseafloor biosphere, with the ability to interact with other microbial populations by synthesizing antimicrobial compounds (Navarri et al. 2016).
THE GREEN ALGA AND THE SALAMANDER:
A SUFFOCATING LOVE STORY
Burns J.A.1, Zhang H.2, Hill E.2, Kerney R.2, Kim E.1
1 - American Museum of Natural History
2 - Gettysburg College [email protected]
The recently discovered endosymbiosis between the green alga Oophila amblystomatis and the salamander Ambystoma maculatum is a unique relationship among the chloroplastida and vertebrates. Using a dual RNA-seq approach, we assembled novel transcriptomes ofthese two organisms and identified differentially expressed transcripts between ecto-and endo-symbiotic algae as well as between salamander cells with and without endosymbiotic algae. The results offer a glimpse at the changes in both organisms that take place during this novel endosymbiosis. We found that the intracellular algae downregulate nutrient transporters related to phosphate and nitrogen acquisition from the environment. They also exhibit hallmarks of cellular stress, especially related to osmotic stress, sulfur starvation, and hypoxia. Further, the results suggest that the alga undergoes a large scale metabolic shift from oxidative metabolism to fermentation with the potential evolution ofhydrogen gas. The salamander cells exhibit milder differences, including changes in gene expression indicating the initiation of an innate immune response to the alga, and alterations in nutrient sensing related to insulin sensitivity. The salamander cells do not exhibit large scale stress or apoptotic responses suggesting that intracellular algae are not a big drain on the salamander cell's resources.
GENOME AND TRANSCRIPTOME OF HEMI-STASIA PHAEOCYSTICOLA, A FLAGELLATE RELATED TO A NOVEL HYPER-DIVERSE CLADE OF MARINE PROTISTS Butenko A.1, Yabuki A.2, Flegontova O.34, Horak A.3, Flegontov P.135, Lukes J.346 1 - Life Science Research Centre, Faculty ofScience,
Protistology ■ 11
University of Ostrava, 710 00 Ostrava, Czech Republic
2 - Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15Natsushima, Yokosuka, Kanagawa 237-0061, Japan
3 - Biology Centre, Institute of Parasitology, Czech Academy of Sciences, 370 05 Ceske Budejovice (Budweis), Czech Republic
4 - Faculty of Science, University of South Bohemia, 370 05 Ceske Budejovice (Budweis), Czech Republic
5 - A.A. Kharkevich Institute for Information Transmission Problems, Russian Academy ofSciences, 127 051 Moscow, Russian Federation
6 - Canadian Institute for Advanced Research, Toronto, Ontario M5G1Z8, Canada [email protected]
Diplonemea (Euglenozoa) is an understudied group of heterotrophic flagellates, related to euglenids and kinetoplastids. Diplonemids are abundant in the deep ocean and, surprisingly, represent the most diverse clade of pelagic eukaryotes, according to our metabarcoding data. There are four major clades within diplonemids: i/ clade of 'classic' diplonemids, Diplonema and Rhynchopus; ii/ small clade of Hemistasia; iii/ small clade of environmental sequences (DSPD II, deep-sea pelagic diplonemids II); iv/ large clade of environmental sequences (DSPD I). The DSPD I clade accounts for >97% of diplonemid abundance and diversity in the oceanic plankton, and Hemistasiaphaeocysticola, a recently isolated marine flagellate that feeds on diatoms and dinoflagellates, appears to be the closest relative of DSPD I according to some phylogenetic analyses. It not clear whether H. phaeocysticola is a predator, a parasite, or a scavenger of dead cells. An axenic culture was obtained from H. phaeocysticola growing with Thalassiosira cf. rotula. The genome and transcriptome of H. phaeocysticola were sequenced using 300 and 250 nt paired-end Illumina MiSeq reads, respectively. A draft genome assembly was obtained using CLC Genomics Workbench v.8.1 and has the length of ~260 Mbp and N50 of1.5 kbp. The results suggest that the genome of H. phaeocysticola is similar to that of Diplonema papillatum in size and has a very high repeat content. Additional genome sequencing using PacBio will be performed and the metabolism of H. phaeocysticola will be studied using a transcriptome assembly.
MIXOTROPHIC CILIATES AS SPECIAL ECOLOGICAL GROUP IN WATERBODIES OF CENTRAL AND LOWER VOLGA AND KAMA Bykova S.V.
Institute of ecology of the Volga river basin of RAS [email protected]
In plankton of polytypic waterbodies from Cent-
ral, Lower Volga and Kama 39 species of the mixotrophic ciliates are revealed. Their structure is heterogeneous: there are "epilimnic" aerophylic myxotrophs and microaerophylic or anaerobic myxotrophs. The first group appears in the low trophic state reservoirs; reservoirs with unstable stratification; in the epilimnium of the stratified waterbodies; in acid, colored, with level fluctuation waterbodies. The second group prefers microaerobic and anaerobic conditions of stratified eutrophic and hypertrophic lakes with high sulfides concentration. The absolute maximums of abundance (206540 ind./l) and biomass (7264 mg/m3) of mixotrophs are registered during summer stratification in a highly trophic meromictic pond, and the maximum contribution to biomass - in the small polyhumic lakes (98%).The ciliates' mixotrophic biomass (6,1 g/m3) is comparable with the anoxic phototrophic bacteria biomass (9,6 g/m3) and phytoflagellates (2,6 g / m3) in chemocline and adjacent layers. Their contribution to the overall "phototrophic" component biomass reaches about 37%, while in other waterbodies the total biomass of ciliates several orders of magnitude less than the biomass of other protists and bacteria. The scheme of different mixotrophs species confinement to various waterbodies and ecotopes in gradient of major abiotic factors has been drawn. An inverse relationship between environmental indicators saprobity and mixotrophic ciliates percentage was shown on example of oligo-mesotrophic lake. This can be used when assessing the state of aquatic ecosystems. It was proved that the species composition and the nature of their distribution are determined by specific abiotic and biotic conditions and weakly dependent on the zonal factors.
THE ROLE OF PROTISTS IN THE PLANKTON COMMUNITY OF FRESHWATER LAKE IN THE PERIOD OF ITS EUTROPHICATION Bykova S.V., Umanskaya M.V., Gorbunov M.U., Tarasova N.G., Zharikov V.V., Muchortova O.V. Institute of ecology of the Volga river basin of RAS [email protected]
The Lake Kandry-Kul is one of the largest natural lakes of the Middle Volga basin. It is a popular resting place and therefore experience significant recreation load. From 2010 to 2012 the trophic level ofthe lake has increased from a predominantly oligotrophic to mesotrophic. We studied the following groups ofprotists: ciliates, dinoflagellates, chrysophytes, cryptophytes and euglenids. Their biomass in 2012 compared to 2010 has increased 2.4 times. Their contribution to the total biomass of plankton community and to the to-tal unicellular
