Takahiko Akematsu
A5062873438- Protist diversity and phylogeny
- Autophagy in Disease and Therapy
- Toxoplasma gondii Research Studies
- Marine Biology and Ecology Research
- RNA Interference and Gene Delivery
- Microbial Community Ecology and Physiology
- Plant responses to water stress
- Epigenetics and DNA Methylation
- Chromosomal and Genetic Variations
- Cell death mechanisms and regulation
- Geology and Paleoclimatology Research
- Parasitic Infections and Diagnostics
- DNA Repair Mechanisms
- Endoplasmic Reticulum Stress and Disease
- Trypanosoma species research and implications
- Cancer therapeutics and mechanisms
- Marine and coastal plant biology
- Renal and related cancers
- Polyamine Metabolism and Applications
- Trace Elements in Health
- bioluminescence and chemiluminescence research
- Genomics and Phylogenetic Studies
- Protein Structure and Dynamics
- Microtubule and mitosis dynamics
- Cytomegalovirus and herpesvirus research
Kanagawa University
2025
Nihon University
2022-2025
University of Vienna
2016-2019
York University
2010-2015
Kanazawa University
2007-2014
Kanazawa Hospital
2010
Kōchi University
2004-2007
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, on this topic has continued to accelerate, and many new scientists have entered field. Our knowledge base relevant technologies also been expanding. Accordingly, it is important update these monitoring autophagy different organisms. Various reviews described range assays that used purpose. Nevertheless, there continues be confusion regarding acceptable methods measure autophagy, especially...
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, on this topic has continued to accelerate, and many new scientists have entered field. Our knowledge base relevant technologies also been expanding. Accordingly, it is important update these monitoring autophagy different organisms. Various reviews described range assays that used purpose. Nevertheless, there continues be confusion regarding acceptable methods measure autophagy, especially...
Pathogenic protists are a group of organisms responsible for causing variety human diseases including malaria, sleeping sickness, Chagas disease, leishmaniasis, and toxoplasmosis, among others. These diseases, which affect more than one billion people globally, mainly the poorest populations, characterized by severe chronic stages lack effective antiparasitic treatment. Parasitic display complex life-cycles go through different cellular transformations in order to adapt hosts they live in....
Programmed nuclear death (PND), which is also referred to as apoptosis, a remarkable process that occurs in ciliates during sexual reproduction (conjugation). In Tetrahymena thermophila, when the new macronucleus differentiates, parental selectively eliminated from cytoplasm of progeny, concomitant with apoptotic events. However, molecular mechanisms underlying these events are not well understood. The engulfed by large autophagosome, contains numerous mitochondria have lost their membrane...
During sexual reproduction in the ciliate Tetrahymena thermophila, meiosis occurs germline micronucleus, resulting formation of four haploid micronuclei. Of these, only one is selected to evade autophagy, and subsequently migrates membrane junction with partner cell for reciprocal pronuclear exchange. We previously demonstrated that transmembrane protein Semi1 essential this nuclear migration. specifically expressed mating cells localizes periphery nucleus. Loss disrupts attachment junction,...
During post-zygotic development, the ciliate Oxytricha trifallax undergoes massive programmed genome rearrangement that involves over 225,000 DNA cleavage and joining events. An family of Tc 1/mariner transposons, known as Telomere-Bearing Elements (TBEs), encodes a transposase has been implicated in rearrangement, but its high copy number (>34,000 paralogs) precluded genetic strategies to investigate recognition properties directly . Here, we developed heterologous strategy assay TBE...
Programmed nuclear death (PND) in Tetrahymena is a unique process during conjugation, which only the parental macronucleus degraded and then eliminated from progeny cytoplasm, but other co-existing nuclei such as new micro- macronuclei are unaffected. PND through autophagic elimination expected to be strictly controlled, considering significant roles ciliates turnover of disused organelles production next generation. Here we demonstrate that involves peculiar aspects autophagy, differ...
Based on observations of markers for DNA lesions, such as phosphorylated histone H2AX (γH2AX) and open ends, it has been suggested that post-meiotic double-strand breaks (PM-DSBs) enable chromatin remodeling during animal spermiogenesis. However, the existence PM-DSBs is unconfirmed, mechanism responsible their formation unclear. Here, we report first direct observation programmed via electrophoretic separation DSB-generated fragments in ciliate Tetrahymena thermophila. These are accompanied...
Programmed nuclear death (PND) in the ciliate protozoan Tetrahymena thermophila is a novel type of autophagy that occurs during conjugation, which only parental somatic macronucleus destined to die and then eliminated from progeny cytoplasm. Other coexisting nuclei, however, such as new micro- macronuclei are unaffected. PND starts with condensation nucleus followed by apoptotic DNA fragmentation, lysosomal acidification, final resorption. Because peculiarity process absence some ATG genes...
Programmed nuclear death (PND) in the ciliate Tetrahymena is an apoptosis-like phenomenon that occurs a restricted space of cytoplasm during conjugation. In process, only parental macronucleus selectively eliminated from progeny cytoplasm, conjunction with differentiation new macronuclei for next generation. For last decade, mitochondria have been elucidated to be crucial executioner like apoptosis: apoptosis-inducing factor and yet-unidentified nucleases localised are major factors PND.To...
SUMMARY The ciliated protozoan Tetrahymena thermophila has evolved remarkable nuclear dualism that involves spatial segregation of the polyploid somatic macro- and canonical diploid germinal micronucleus in a single cytoplasm. Programmed death (PND), also referred to as apoptosis, is catabolic process occurs during conjugation finish lifespan parental soma, which only macronucleus eliminated from cytoplasm, but other co-existing nuclei are unaffected. We found PND unique aspects autophagy,...
The extrusion of macronuclear chromatin is a remarkable characteristic during encystment in Colpoda, but the biological significance this phenomenon has not been fully elucidated. Here we demonstrate that occurs with high frequency when was induced by increasing Ca(2+) growing cells various stages cell cycle. Feulgen-DNA reaction revealed vegetatively have more DNA than stationary phase, suggesting an association content execution extrusion. Using 4',6-diamidino-2-phenylindole (DAPI), found...
Heat shock protein 70 (Hsp70) is a member of family conserved chaperone proteins whose function well investigated in many model organisms. Here we focus on an Hsp70 called Ssa5 the ciliate protozoan Tetrahymena thermophila, and reveal that its translation heat inducible as for general Hsps. Moreover, abundantly expressed cytoplasm during sexual reproduction (conjugation) response to heat-stress. Knocking out SSA5 (ΔSSA5) does not affect survival cell under heat-stress, likely due other...
6-methylpurine (6mp) is a toxic analog of adenine that inhibits RNA and protein synthesis interferes with salvage mediated by phosphoribosyltransferase (APRTase). Mutants the ciliated protist Tetrahymena thermophila are resistant to 6mp were isolated in 1974, but mechanism resistance has remained unknown. To investigate T. thermophila, we created 6mp-resistant strains identified mutation APRTase genomic locus (APRT1) responsible for resistance. While overexpression mutated APRT1 allele...
During sexual reproduction in the ciliate, Tetrahymena thermophila, cells of complementary mating type pair ("conjugate") undergo simultaneous meiosis and fertilize each other. In both partners only one four meiotic products is "selected" to escape autophagy, this nucleus divides mitotically produce two pronuclei. The migrating pronucleus cell translocates partner fuses with its stationary vice versa. Selection designated gametic was thought depend on position within because it always...
In the absence of O2, step-up photophobic response Blepharisma japonicum is suppressed. To evaluate possibility that reactivated oxygen species (ROS) produced by blepharismin photosensitization are involved in primary transduction for B. japonicum, effects OH radical scavengers and singlet quencher on were examined. The reagents used present assays hardly suppressed response, even though rescued from photodynamic killing cells. Alternatively, presence an electron acceptor, latency was...