A5057243014- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Microbial Community Ecology and Physiology
- Photosynthetic Processes and Mechanisms
- Insect symbiosis and bacterial influences
- Parasitic Infections and Diagnostics
- Hemoglobin structure and function
- Heme Oxygenase-1 and Carbon Monoxide
- Algal biology and biofuel production
- CRISPR and Genetic Engineering
- Legume Nitrogen Fixing Symbiosis
- Research on Leishmaniasis Studies
- Toxoplasma gondii Research Studies
- Trypanosoma species research and implications
- Diatoms and Algae Research
- Marine Biology and Ecology Research
- Legionella and Acanthamoeba research
- Nematode management and characterization studies
- Paleontology and Stratigraphy of Fossils
- Plant nutrient uptake and metabolism
- Environmental DNA in Biodiversity Studies
- Chromosomal and Genetic Variations
- Evolution and Genetic Dynamics
- Coastal wetland ecosystem dynamics
- Nanoparticles: synthesis and applications
National Museum of Nature and Science
2016-2023
University of Tsukuba
2014-2020
Dalhousie University
2009-2017
Canadian Institute for Advanced Research
2009-2014
Graduate School USA
2010
Yamagata University Hospital
2006
Yamagata University
2004
Cryptophyte and chlorarachniophyte algae are transitional forms in the widespread secondary endosymbiotic acquisition of photosynthesis by engulfment eukaryotic algae. Unlike most plastid-bearing algae, miniaturized versions endosymbiont nuclei (nucleomorphs) persist cryptophytes chlorarachniophytes. To determine why, to address other fundamental questions about eukaryote-eukaryote endosymbiosis, we sequenced nuclear genomes cryptophyte Guillardia theta Bigelowiella natans. Both have >21,000...
Significance Members of the diatom family Rhopalodiaceae possess a cyanobacterial endosymbiont called “spheroid body.” The spheroid body evolved much more recently than did mitochondria or plastids and is predicted to fix nitrogen. Here we present what is, our knowledge, first completely sequenced genome from rhopalodiacean diatom. Comparative analyses revealed that metabolically reduced, confirming its status as an obligate endosymbiont. possesses genes for nitrogen fixation, and, surprise,...
Nucleomorphs are relic endosymbiont nuclei so far found only in two algal groups, cryptophytes and chlorarachniophytes, which have been studied to model the evolutionary process of integrating an alga into a host-governed plastid (organellogenesis). However, past studies suggest that DNA transfer from host had already ceased both implying organellogenesis at genetic level has completed systems. Moreover, we yet pinpoint closest free-living relative endosymbiotic engulfed by ancestral...
The cryptomonads are a group of unicellular algae that acquired photosynthesis through the engulfment red algal cell, process called secondary endosymbiosis.Here, we present complete plastid genome sequence secondarily nonphotosynthetic species Cryptomonas paramecium CCAP977/2a.The ;78 kilobase pair (Kbp) C. contains 82 predicted protein genes, 29 transfer RNA and single pseudogene (atpF).The is approximately 50 Kbp smaller than those photosynthetic Guillardia theta Rhodomonas salina; 71...
Nucleomorphs are the remnant nuclei of algal endosymbionts that were engulfed by nonphotosynthetic host eukaryotes. These peculiar organelles found in cryptomonad and chlorarachniophyte algae, where they evolved from red green endosymbionts, respectively. Despite their independent origins, nucleomorph genomes similar size structure: both <1 million base pairs (the smallest nuclear known), comprised three chromosomes, possess subtelomeric ribosomal DNA operons. Here, we report complete...
Nonphotosynthetic plastids retain important biological functions and are indispensable for cell viability. However, the detailed processes underlying loss of plastidal other than photosynthesis remain to be fully understood. In this study, we used transcriptomics, subcellular localization, phylogenetic analyses characterize biochemical complexity nonphotosynthetic apochlorotic diatom Nitzschia sp. NIES-3581. We found that these have lost isopentenyl pyrophosphate biosynthesis...
Unlike many other photosynthetic dinoflagellates, whose plastids contain a characteristic carotenoid peridinin, members of the genus Lepidodinium are only known dinoflagellate species possessing green alga-derived plastids. However, precise origin has hitherto remained uncertain. In this study, we completely sequenced plastid genome chlorophorum NIES-1868. Our phylogenetic analyses 52 plastid-encoded proteins unite L. exclusively with pedinophyte, Pedinomonas minor, indicating that...
Endosymbiotic relationships between eukaryotic and prokaryotic cells are common in nature. Endosymbioses two eukaryotes also known; cyanobacterium-derived plastids have spread horizontally when one eukaryote assimilated another. A unique instance of a non-photosynthetic, endosymbiont involves members the genus Paramoeba, amoebozoans that infect marine animals such as farmed fish sea urchins. Paramoeba species harbor endosymbionts belonging to Kinetoplastea, diverse group flagellate protists...
Organisms with nonphotosynthetic plastids often retain genomes; their gene contents provide clues as to the functions of these organelles. Yet functional roles some retained genes—such those coding for ATP synthase—remain mysterious. In this study, we report complete plastid genome and transcriptome data a diatom propose that its synthase genes may function in hydrolysis maintain proton gradient between thylakoids stroma, required by twin arginine translocator (Tat) system translocation...
Cryptophytes are a diverse lineage of marine and freshwater, photosynthetic secondarily nonphotosynthetic algae that acquired their plastids (chloroplasts) by "secondary" (i.e., eukaryote–eukaryote) endosymbiosis. Consequently, they among the most genetically complex cells known have four genomes: mitochondrial, plastid, "master" nuclear, residual nuclear genome secondary endosymbiotic origin, so-called "nucleomorph" genome. Sequenced nucleomorph genomes ∼1,000-kilobase pairs (Kbp) or less...
Secondary loss of photosynthesis is observed across almost all plastid-bearing branches the eukaryotic tree life. However, genome-based insights into transition from a phototroph secondary heterotroph have so far only been revealed for parasitic species. Free-living organisms can yield unique evolutionary consequence photosynthesis, as lifestyle requires specific adaptations to host environments. Here, we report on diploid genome free-living diatom Nitzschia putrida (35 Mbp),...
Nucleomorphs are residual nuclei derived from eukaryotic endosymbionts in chlorarachniophyte and cryptophyte algae. The that gave rise to nucleomorphs plastids these two algal groups were green red algae, respectively. Despite their independent origin, the nucleomorph genomes share similar genomic features such as extreme size reduction a three-chromosome architecture. This suggests reductive evolutionary forces have acted shape groups. Thus far, however, only single plastid genome has been...
Perkinsela is an enigmatic early-branching kinetoplastid protist that lives as obligate endosymbiont inside Paramoeba (Amoebozoa). We have sequenced the highly reduced mitochondrial genome of Perkinsela, which possesses only six protein-coding genes (cox1, cox2, cox3, cob, atp6, and rps12), despite fact organelle itself contains more DNA than present in either host or nuclear genomes. An silico analysis two strains showed RNA editing processing machineries typical flagellates are generally...
All members of the order Trypanosomatida known to date are parasites that most likely descendants a free-living ancestor.Trypanosomatids an excellent model assess transition from parasitic lifestyle, because large amount experimental data has been accumulated for well-studied harmful humans and livestock (Trypanosoma spp.and Leishmania spp.).However, recent advances in our understanding diversity trypanosomatids their close relatives (i.e., class Kinetoplastea) have suggested change...
The fornicata (fornicates) is a eukaryotic group known to consist of free-living and parasitic organisms. Genome datasets two model fornicate parasites Giardia intestinalis Spironucleus salmonicida are well annotated, so far. nuclear genomes G. assemblages S. small in terms the genome size simple structure. However, an ancestral genomic structure gene contents, from which have evolved, remains be clarified. In order understand evolution fornicates, here, we present draft sequence fornicate,...
Cyanobacteria are one of the most important contributors to oceanic primary production and survive in a wide range marine habitats. Much effort has been made understand their ecological features, diversity, evolution, based mainly on data from free-living cyanobacterial species. In addition, symbiosis emerged as an lifestyle microbes increasing knowledge cyanobacteria symbiotic relationships with unicellular eukaryotes suggests significance understanding global ecosystem. However, detailed...
Abstract Chlorarachniophyte algae possess four DNA-containing compartments per cell, the nucleus, mitochondrion, plastid and nucleomorph, latter being a relic nucleus derived from secondary endosymbiont. While evolutionary dynamics of nucleomorph genomes have been investigated, comparative investigation mitochondrial (mtDNAs) has not carried out. We sequenced complete mtDNA Lotharella oceanica compared it to that another chlorarachniophyte, Bigelowiella natans . The linear L. is 36.7 kbp in...
Abstract Loss of photosynthesis is a recurring theme in eukaryotic evolution. In organisms that have lost the ability to photosynthesize, nonphotosynthetic plastids are retained because they play essential roles processes other than photosynthesis. The unicellular algal genus Cryptomonas contains both photosynthetic and members, latter having photosynthesize on at least three separate occasions. To elucidate evolutionary underlying loss photosynthesis, we sequenced plastid genomes two...
We here report the phylogenetic position of barthelonids, small anaerobic flagellates previously examined using light microscopy alone. Barthelona spp. were isolated from geographically distinct regions and we established five laboratory strains. Transcriptomic data generated one strain (PAP020) used for large-scale, multi-gene (phylogenomic) analyses. Our analyses robustly placed PAP020 at base Fornicata clade, indicating that barthelonids represent a deep-branching metamonad clade....
Kinetoplastea is a diverse protist lineage composed of several the most successful parasites on Earth, organisms whose metabolisms have coevolved with those they infect. Parasitic kinetoplastids emerged from free-living, non-pathogenic ancestors multiple occasions during evolutionary history group. Interestingly, in both parasitic and free-living kinetoplastids, heme pathway-a core metabolic pathway wide range organisms-is incomplete or entirely absent. Indeed, investigated thus far seem to...
Abstract It is widely held that sterols are key cyclic triterpenoid lipids in eukaryotic cell membranes and synthesized through oxygen‐dependent multienzyme pathways. However, there known exceptions―ciliated protozoans, such as Tetrahymena , along with diverse low‐oxygen‐adapted eukaryotes produce, instead of sterols, the lipid tetrahymanol does not require molecular oxygen for its biosynthesis. Here, we report a number anaerobic microbial (protists) utilize neither nor their membranes. The...
Reductive genome evolution is seen in organisms living close association with each other, such as endosymbiosis, symbiosis, and parasitism. The reduced genomes of endosymbionts parasites often exhibit similar features high gene densities A+T compositional bias. Little known about how the regulation expression has been affected highly compacted genomes. We studied transcription patterns "nucleomorph" genomes, which are relic nuclear algal found cryptophytes chlorarachniophytes. examined...