A5073325974- Algal biology and biofuel production
- Marine and coastal plant biology
- Protist diversity and phylogeny
- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Photosynthetic Processes and Mechanisms
- Aquatic Ecosystems and Phytoplankton Dynamics
- Plant Molecular Biology Research
- Biocrusts and Microbial Ecology
- Light effects on plants
- Marine Biology and Ecology Research
- Evolution and Genetic Dynamics
- Genomics and Phylogenetic Studies
- Physiological and biochemical adaptations
- Plant Virus Research Studies
- Neurobiology and Insect Physiology Research
- Plant tissue culture and regeneration
- Microtubule and mitosis dynamics
- Insect and Arachnid Ecology and Behavior
- Diatoms and Algae Research
- Micro and Nano Robotics
- Aquatic Invertebrate Ecology and Behavior
- Sperm and Testicular Function
- Legume Nitrogen Fixing Symbiosis
- Chromosomal and Genetic Variations
Hosei University
2021-2023
The University of Tokyo
2012-2021
Tokyo University of Science
2012-2017
Keio University
2012
National Institute for Basic Biology
2007
Tokyo Metropolitan University
2004
The transition to multicellularity has occurred numerous times in all domains of life, yet its initial steps are poorly understood. volvocine green algae a tractable system for understanding the genetic basis including formation cooperative cell groups. Here we report genome sequence undifferentiated colonial alga, Gonium pectorale, where group evolved by co-option retinoblastoma cycle regulatory pathway. Significantly, expression regulator unicellular Chlamydomonas causes it become...
Volvocine green algae represent the "evolutionary time machine" model lineage for studying multicellularity, because they encompass whole range of evolutionary transition multicellularity from unicellular Chlamydomonas to >500-celled Volvox. Multicellular volvocalean species including Gonium pectorale and Volvox carteri generally have several common morphological features survive as integrated multicellular organisms such "rotational asymmetry cells" so that cells become components...
Male and female gametes differing in size-anisogamy-emerged independently from isogamous ancestors various eukaryotic lineages, although genetic bases of this emergence are still unknown. Volvocine green algae a model lineage for investigating the transition isogamy to anisogamy. Here we focus on two closely related volvocine genera that bracket transition-isogamous Yamagishiella anisogamous Eudorina. We generated de novo nuclear genome assemblies both sexes Eudorina identify dimorphic...
:Chloromonas brevispina and C. nivalis (Volvocales, Chlorophyceae) are considered cosmopolitan, as the aplanozygotes assignable to two species distributed worldwide. Although recent phylogenetic analyses have indicated possible polyphyly of identified nivalis, analytical resolution was not robust, possibly because only single genes were analysed. Here, we obtained long sequences multiple DNA regions from 50 identical [on basis light microscopy (LM)] in a field-collected sample, positions...
In gametophytic cells (prothalli) of the fern Adiantum capillus-veneris, nuclei as well chloroplasts change their position according to light conditions. Nuclei reside on anticlinal walls in darkness and move periclinal or under weak strong conditions, respectively. Here we reveal that red light-induced nuclear movement is mediated by neochrome1 (neo1), blue redundantly neo1, phototropin2 (phot2) possibly phot1, dark positioning both phot2. Thus, chloroplast photorelocation movements share...
The centriolar triplet microtubule consists of an A-tubule with 13 protofilaments, and B- C-tubules, each 10 protofilaments. Although the formation triplets has been shown to require γ-tubulin, its specific role in tubule remains elusive. We isolated two novel Chlamydomonas reinhardtii mutants, bld13-1 bld13-2, expressing γ-tubulin a single amino-acid substitution (T292I, E89D, respectively). Similar known centriole-deficient both mutants exhibited defects ciliary assembly, nuclear number,...
RNA interference (RNAi) has become a powerful tool for determining gene function and is used in wide variety of organisms. Since it necessary to generate double-stranded (dsRNA) as an inducer RNAi, preparation RNAi-inducing constructs somewhat cumbersome time consuming, especially the thousands genes genome-wide analysis. To overcome these problems, we have developed more convenient gene-silencing method fern Adiantum using DNA (dsDNA) model system functional analysis plants. Delivery dsDNA...
Significance Evolutionary transitions between species with separate sexes and in which individuals have both sex functions wide-ranging biological implications. It is largely unknown how such occur systems haploid male- female-determining chromosomes algae bryophytes. We investigated a transition the algal genus Volvox by making whole-genome sequences of two closely related species, one heterothallic (with distinct males females) other homothallic only bisexual, self-compatible individuals)....
Abstract The coexistence of three sexual phenotypes (male, female and bisexual) in a single species, ‘trioecy’, is rarely found diploid organisms such as flowering plants invertebrates. However, trioecy haploid has only recently been reported green algal Pleodorina starrii . Here, we generated whole-genome data the sex P. to reveal reorganization ancestral sex-determining regions (SDRs) chromosomes: male bisexual had same “male SDR” with paralogous gene expansions male-determining MID ,...
Volvocalean green algae have among the most diverse mitochondrial and plastid DNAs (mtDNAs ptDNAs) from eukaryotic domain. However, nearly all of organelle genome data this group are restricted to unicellular species, like Chlamydomonas reinhardtii, presently only one multicellular ∼4,000-celled Volvox carteri, has had its sequenced. The V. carteri genomes repeat rich, ptDNA is largest plastome ever Here, we present complete mtDNA colonial volvocalean Gonium pectorale, which comprised ∼16...
The molecular bases for the evolution of male–female sexual dimorphism are possible to study in volvocine algae because they encompass entire range reproductive morphologies from isogamy oogamy. In 1978, Charlesworth suggested model a gamete size gene becoming linked sex-determining or mating type locus (MT) as mechanism anisogamy. Here, we carried out first comprehensive candidate MT-linked oogamy gene, MAT3/RB, across lineage. We found that anisogamy/oogamy predates extremely high...
Volvocine algae, which range from the unicellular Chlamydomonas to multicellular Volvox with a germ-soma division of labor, are model for evolution multicellularity. Within this group, spheroidal colony might have evolved in two independent lineages: Volvocaceae and goniacean Astrephomene. Astrephomene produces colonies posterior somatic cells. The feature that distinguishes volvocacean algae is lack inversion during embryogenesis; embryo undergoes after successive divisions orient flagella...
Species of Volvox sect. (Volvocaceae, Chlorophyceae) are unique because they have thick cytoplasmic bridges between somatic cells and spiny‐walled zygotes. This section is taxonomically important the genus polyphyletic. However, taxonomic studies species in not been carried out on cultured material. Here, we performed a study monoecious based comparative morphology molecular phylogeny chloroplast genes internal transcribed spacer (ITS) regions nuclear rDNA using various strains originating...
ABSTRACT Male and female, generally defined based on differences in gamete size motility, likely have multiple independent origins, appearing to evolved from isogamous organisms various eukaryotic lineages. Recent studies of the fusogen GCS1/HAP2 indicate that this protein is deeply conserved across eukaryotes, its exclusive and/or functional expression resides males or male homologues. However, little known regarding primitive molecular traits females within eukaryotes. Here, using...
Volvox is a very interesting oogamous organism that exhibits various types of sexuality and/or sexual spheroids depending upon species or strains. However, molecular bases such reproduction characteristics have not been studied in this genus. In the model V. carteri, an ortholog minus mating type-determining dominance gene (MID) isogamous Chlamydomonas reinhardtii male-specific and determines sperm formation. Male female genders are genetically determined (heterothallism) whereas several...
Chlamydomonadalean green algae are no stranger to linear mitochondrial genomes, particularly members of the Reinhardtinia clade. At least nine different species known have DNAs (mtDNAs), including model Chlamydomonas reinhardtii. Thus, it is surprise that some suggested most recent common ancestor clade had a mtDNA. But uncovering circular-mapping mtDNAs in range algae, such as Volvox carteri and Tetrabaena socialis, has shed doubt on this hypothesis. Here, we explore mtDNA sequence...
The volvocine lineage, containing unicellular Chlamydomonas reinhardtii and differentiated multicellular Volvox carteri, is a powerful model for comparative studies aiming at understanding emergence of multicellularity. Tetrabaena socialis the simplest alga belongs to family Tetrabaenaceae that sister more complex families, Goniaceae Volvocaceae. Thus, T. key species elucidate initial steps in evolution In asexual life cycle C. species, reproductive cells form daughter cells/colonies by...
Volvox rousseletii is a dioecious species belonging to sect. that has previously only been found in Africa. During field surveys large dam lake (Lake Sagami) Kanagawa Prefecture, central Japan, we encountered produces sexual spheroids the water column. Although induction of this culture did not produce adequately well-developed for identification, molecular data directly obtained from field-collected verified identity male and female as well cultured materials. Based on morphological data,...
Plastid genomes are not normally celebrated for being large. But researchers steadily uncovering algal lineages with big and, in rare cases, enormous plastid DNAs (ptDNAs), such as volvocine green algae. Plastome sequencing of five different species has revealed some the largest, most repeat-dense plastomes on record, including that Volvox carteri (∼525 kb). Volvocine algae have also been used models testing leading hypotheses organelle genome evolution (e.g., mutational hazard hypothesis),...
Mating systems of haploid species such as fungi, algae, and bryophytes are either heterothallic (self-incompatible) with two sex phenotypes (male female, or mating type minus plus in isogamous species) homothallic (self-compatible) only a bisexual phenotype producing zygotes within clone. The anisogamous volvocine green alga Pleodorina starrii is previously reported to have system. Here, we found that additional culture strains originating from the same water system P. were taxonomically...
SUMMARY The diversity and the evolution of mating systems have been studied in various eukaryotes. Volvox sect. volvocine green algae is suitable for evolutionary studies transition from homothallic to heterothallic because this recognized distal lineages within . MID homologs are important determining type minus male species algae. However, not entire Here, we analyzed almost all taxa found no significant differences sequences between males species. Furthermore, genotype rousseletii showed...