A5101996325- Protist diversity and phylogeny
- Microbial Community Ecology and Physiology
- Genomics and Phylogenetic Studies
- Photosynthetic Processes and Mechanisms
- Diatoms and Algae Research
- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Marine Ecology and Invasive Species
- Marine and coastal plant biology
- Biocrusts and Microbial Ecology
- Algal biology and biofuel production
- Paleontology and Stratigraphy of Fossils
- Legume Nitrogen Fixing Symbiosis
- Parasite Biology and Host Interactions
- Parasitic Infections and Diagnostics
- Aquatic Ecosystems and Phytoplankton Dynamics
- Polar Research and Ecology
- Environmental DNA in Biodiversity Studies
- Advanced Proteomics Techniques and Applications
- Heat shock proteins research
- Environmental Monitoring and Data Management
- Methane Hydrates and Related Phenomena
- Microtubule and mitosis dynamics
- Insect symbiosis and bacterial influences
- Chemistry and Stereochemistry Studies
University of Tsukuba
2015-2025
Kanazawa University
2003-2013
Life University
2012
Dalhousie University
2007-2009
University of British Columbia
2000-2007
University of New Brunswick
2007
Canadian Institute for Advanced Research
2003
Tokyo Institute of Technology
1997
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...
Chlorarachniophytes are amoeboflagellate algae that acquired photosynthesis secondarily by engulfing a green alga and retaining its plastid (chloroplast). An important consequence of secondary endosymbiosis in chlorarachniophytes is most the nuclear genes encoding plastid-targeted proteins have moved from nucleus endosymbiont to host nucleus. We sequenced analyzed 83 cDNAs 78 model chlorarachniophyte Bigelowiella natans (formerly Chlorarachnion sp. CCMP621). Phylogenies inferred majority...
The light-harvesting complexes (LHCs) of land plants and green algae have essential roles in light capture photoprotection. Though the functional diversity individual LHC proteins are well described many plants, extent this family majority algal groups is unknown. To examine evolution chlorophyll a/b antennae system to infer its ancestral state, we initiated several expressed sequence tag projects from a taxonomically broad range a/b-containing protists. This included representatives...
Recent phylogenetic analyses position certain "orphan" protist lineages deep in the tree of eukaryotic life, but their exact placements are poorly resolved. We conducted phylogenomic that incorporate deeply sequenced transcriptomes from representatives collodictyonids (diphylleids), rigifilids, Mantamonas, and ancyromonads (planomonads). Analyses 351 genes, using site-heterogeneous mixture models, strongly support a novel super-group-level clade includes collodictyonids, which we name...
Phagocytosis is a key eukaryotic feature, conserved from unicellular protists to animals, that enabled eukaryotes feed on other organisms. It could also be driving force behind endosymbiosis, process by which α-proteobacteria and cyanobacteria evolved into mitochondria plastids, respectively. Here we describe planctomycete bacterium, 'Candidatus Uab amorphum', able engulf bacteria small cells through phagocytosis-like mechanism. Observations via light electron microscopy suggest this...
Several dinoflagellate species have plastids that more closely resemble those of an unrelated algal group, the haptophytes, suggesting these been obtained by tertiary endosymbiosis. Because both groups are photosynthetic, all genes for nuclear-encoded plastid proteins might be supplied host or some them replaced haptophyte genes. Sequences conserved nuclear psbO gene were from Isochrysis galbana, peridinin-containing Heterocapsa triquetra, and 19'hexanoyloxy-fucoxanthin-containing Karenia...
The cyanobacterium-derived plastids of algae and plants have supported the diversification much extant eukaryotic life. Inferences about early events in plastid evolution must rely on reconstructing that occurred over a billion years ago. In contrast, photosynthetic amoeba Paulinella chromatophora provides an exceptional model to study organelle prokaryote-eukaryote (primary) endosymbiosis approximately 60 mya. Here we sequenced genome (0.977 Mb) from recently described FK01 compared...
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...
The unicellular eukaryotic assemblage Discoba (Excavata) comprises four lineages: the Heterolobosea, Euglenozoa, Jakobida, and Tsukubamonadida. has been considered as a key for understanding early evolution of mitochondrial (mt) genomes, jakobids retain most gene-rich (i.e., primitive) genomes compared with any other eukaryotes determined to date. However, date, mt genome sequences have completed only few groups within Discoba, including jakobids, two closely related heteroloboseans,...
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...
Chlorophylls are essential components of the photosynthetic apparati that sustain all life forms ultimately depend on solar energy. However, a drawback extraordinary photosensitizing efficiency certain chlorophyll species is their ability to generate harmful singlet oxygen. Recent studies have clarified catabolic processes involved in detoxification chlorophylls land plants, but little understood about these strategies aquatic ecosystem. Here, we report variety heterotrophic protists...
Summary In order to obtain insights into the evolution of colorless (apochlorotic) diatoms, we investigated newly established apochlorotic strains N itzschia spp. using light and electron microscopy molecular phylogenetic analyses. Fluorescence microscopic observations demonstrated that diatoms lack chlorophylls. Transmission two also their plastids lacked thylakoids; instead, having four‐membrane‐bound organelles without thylakoids, similar nonphotosynthetic plastid remnants. From strains,...
The phylogeny of the terrestrial cyanobacterium Nostoc commune and its neighboring species was studied using molecular genetic chemotaxonomic approaches. At least eight genotypes N. were characterized by differences among 16S rRNA gene sequences petH encoding ferredoxin-NADP+ oxidoreductase random amplified polymorphic DNA analysis. distributed in Japan without regional specificity. nrtP NrtP-type nitrate/nitrite permease widely genus Nostoc, suggesting that occurrence can be one...
Mantamonads were long considered to represent an "orphan" lineage in the tree of eukaryotes, likely branching near most frequently assumed position for root eukaryotes. Recent phylogenomic analyses have placed them as part "CRuMs" supergroup, along with collodictyonids and rigifilids. This supergroup appears branch at base Amorphea, making it special importance understanding deep evolutionary history However, lack representative species complete genomic data associated has hampered...
Culturing protists offers a powerful approach to exploring eukaryotic diversity, especially for deep-branching lineages. In this study, we cultured and described novel protist species, named Glissandra oviformis n sp., within the poorly studied unclassified genus . While an SSU rDNA gene phylogeny failed resolve its phylogenetic placement in tree, phylogenomic analysis of 340 proteins indicated G. as member CRuMs clade. Prior clade consisted diverse heterotrophic amoeba flagellates lacks...
Marine phytoplankton are major primary producers, and their growth is primarily limited by nitrogen in the oligotrophic ocean environment. The haptophyte Braarudosphaera bigelowii possesses a cyanobacterial endosymbiont (UCYN-A), which plays role fixation ocean. However, host-symbiont interactions poorly understood because B. was unculturable. In this study, we sequenced complete genome of showed that it highly reductive closely related to UCYN-A2 (an ecotype UCYN-A). We succeeded...