博士（理学）, 北海道大学

受精

中心体

微細構造

褐藻類

受精卵

セントリオール

膜融合

セントリン

細胞骨格

免疫電子顕微鏡

細胞質分裂

電子顕微鏡

オルガネラ

ストラメノパイル

多糖類

多細胞化

不等毛藻類

急速凍結置換法

Life Science, Morphology and anatomical structure

Bachelor's degree program, School of Science

Master's degree program, Graduate School of Environmental Science

Doctoral (PhD) degree program, Graduate School of Environmental Science

Mar. 2023, 日本藻類学会, 日本藻類学会論文賞

2019, 国際藻類学会, 国際藻類学会論文賞

2004, 日本植物学会, 日本植物学会奨励賞
長里千香子

2001, 第7回国際藻類学会議, The George F. Papenfuss Poster Award
Chikako Nagasato

1998, 日本藻類学会, 日本藻類学会論文賞
長里千香子

Significant changes in seaweed community structure revealed by a nationwide long-term monitoring survey in Japan 'Monitoring-Site 1000' over the past 15 years (2008-2022)
Ryuta Terada; Takuzo Abe; Shingo Akita; Mitsunobu Kamiya; Hiroshi Kawai; Akira Kurashima; Chikako Nagasato; Yoshihiko Sakanishi; Hiromori Shimabukuro; Haruka Suzuki; Jiro Tanaka; Shinya Uwai; Yuki Watanabe; Ryoko Ueno; Misuzu Aoki
PHYCOLOGICAL RESEARCH, 08 Dec. 2025
English

Observation of the temporal dynamics of the cytoskeleton during cytokinesis in the brown alga Sphacelaria rigidula (Sphacelariales, Phaeophyceae)
Hinako Aoki; Taizo Motomura; Chikako Nagasato
European Journal of Phycology, 03 Nov. 2025
Scientific journal

Light and electron microscopy, molecular phylogeny and mannitol content of Dictyotopsis propagulifera (Dictyotales, Heterokontophyta) isolated from mangrove mud in Perak, Malaysia
John A. West; Taizo Motomura; Seok-Wan Choi; Susan Loiseaux De-Goer; Kathy Ann Miller; Ulf Karsten; Hwan Su Yoon; Phaik Eem Lim; Chikako Nagasato
PHYCOLOGICAL RESEARCH, 73, 3, 210, 221, Jul. 2025
English, Scientific journal

Evolutionary genomics of the emergence of brown algae as key components of coastal ecosystems
France Denoeud; Olivier Godfroy; Corinne Cruaud; Svenja Heesch; Zofia Nehr; Nachida Tadrent; Arnaud Couloux; Loraine Brillet-Guéguen; Ludovic Delage; Dean Mckeown; Taizo Motomura; Duncan Sussfeld; Xiao Fan; Lisa Mazéas; Nicolas Terrapon; Josué Barrera-Redondo; Romy Petroll; Lauric Reynes; Seok-Wan Choi; Jihoon Jo; Kavitha Uthanumallian; Kenny Bogaert; Céline Duc; Pélagie Ratchinski; Agnieszka Lipinska; Benjamin Noel; Eleanor A. Murphy; Martin Lohr; Ananya Khatei; Pauline Hamon-Giraud; Christophe Vieira; Komlan Avia; Svea Sanja Akerfors; Shingo Akita; Yacine Badis; Tristan Barbeyron; Arnaud Belcour; Wahiba Berrabah; Samuel Blanquart; Ahlem Bouguerba-Collin; Trevor Bringloe; Rose Ann Cattolico; Alexandre Cormier; Helena Cruz de Carvalho; Romain Dallet; Olivier De Clerck; Ahmed Debit; Erwan Denis; Christophe Destombe; Erica Dinatale; Simon Dittami; Elodie Drula; Sylvain Faugeron; Jeanne Got; Louis Graf; Agnès Groisillier; Marie-Laure Guillemin; Lars Harms; William John Hatchett; Bernard Henrissat; Galice Hoarau; Chloé Jollivet; Alexander Jueterbock; Ehsan Kayal; Andrew H. Knoll; Kazuhiro Kogame; Arthur Le Bars; Catherine Leblanc; Line Le Gall; Ronja Ley; Xi Liu; Steven T. LoDuca; Pascal Jean Lopez; Philippe Lopez; Eric Manirakiza; Karine Massau; Stéphane Mauger; Laetitia Mest; Gurvan Michel; Catia Monteiro; Chikako Nagasato; Delphine Nègre; Eric Pelletier; Naomi Phillips; Philippe Potin; Stefan A. Rensing; Ellyn Rousselot; Sylvie Rousvoal; Declan Schroeder; Delphine Scornet; Anne Siegel; Leila Tirichine; Thierry Tonon; Klaus Valentin; Heroen Verbruggen; Florian Weinberger; Glen Wheeler; Hiroshi Kawai; Akira F. Peters; Hwan Su Yoon; Cécile Hervé; Naihao Ye; Eric Bapteste; Myriam Valero; Gabriel V. Markov; Erwan Corre; Susana M. Coelho; Patrick Wincker; Jean-Marc Aury; J. Mark Cock
Cell, Elsevier BV, Nov. 2024
Scientific journal

Low-CO2-inducible bestrophins outside the pyrenoid sustain high photosynthetic efficacy in diatoms
Minori Nigishi; Ginga Shimakawa; Kansei Yamagishi; Ryosuke Amano; Shun Ito; Yoshinori Tsuji; Chikako Nagasato; Yusuke Matsuda
Plant Physiology, Oxford University Press (OUP), 13 Mar. 2024
Scientific journal, Abstract

Anion transporters sustain a variety of physiological states in cells. Bestrophins belong to a Cl− and/or HCO3− transporter family conserved in bacteria, animals, algae, and plants. Recently, putative bestrophins were found in the green alga Chlamydomonas reinhardtii, where they are up-regulated under low CO2 conditions and play an essential role in the CO2-concentrating mechanism (CCM). The putative bestrophin orthologs are also conserved in diatoms, secondary endosymbiotic algae harboring red-type plastids, but their physiological functions are unknown. Here, we characterized the subcellular localization and expression profile of bestrophins (BSTs) in the marine diatoms Phaeodactylum tricornutum (PtBST1−4) and Thalassiosira pseudonana (TpBST1 and 2). PtBST1, PtBST2, and PtBST4 localized at the stroma thylakoid membrane outside of the pyrenoid, and PtBST3 localized in the pyrenoid. Contrarily, TpBST1 and TpBST2 both localized in the pyrenoid. These bestrophin proteins accumulated in cells grown in atmospheric CO2 (LC) but not in 1% CO2 (HC)-grown cells. To assess the physiological functions, we generated knock-out mutants for the PtBST1gene by genome editing. The lack of PtBST1 decreased photosynthetic affinity for dissolved inorganic carbon to the level comparable to the HC-grown wild type. Furthermore, non-photochemical quenching in LC-grown cells was 1.5–2.0 times higher in the mutants than in the wild type. These data suggest that HCO3− transport at the stroma thylakoid membranes by PtBST1 is a critical part of the CO2-evolving machinery of the pyrenoid in the fully induced CCM and that PtBST1 may modulate photoprotection under CO2-limited environments in P. tricornutum.

Pyrenoid proteomics reveals independent evolution of the CO2-concentrating organelle in chlorarachniophytes.
Rena Moromizato; Kodai Fukuda; Shigekatsu Suzuki; Taizo Motomura; Chikako Nagasato; Yoshihisa Hirakawa
Proceedings of the National Academy of Sciences of the United States of America, 121, 10, e2318542121, 05 Mar. 2024, [International Magazine]
English, Scientific journal, Pyrenoids are microcompartments that are universally found in the photosynthetic plastids of various eukaryotic algae. They contain ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and play a pivotal role in facilitating CO2 assimilation via CO2-concentrating mechanisms (CCMs). Recent investigations involving model algae have revealed that pyrenoid-associated proteins participate in pyrenoid biogenesis and CCMs. However, these organisms represent only a small part of algal lineages, which limits our comprehensive understanding of the diversity and evolution of pyrenoid-based CCMs. Here we report a pyrenoid proteome of the chlorarachniophyte alga Amorphochlora amoebiformis, which possesses complex plastids acquired through secondary endosymbiosis with green algae. Proteomic analysis using mass spectrometry resulted in the identification of 154 potential pyrenoid components. Subsequent localization experiments demonstrated the specific targeting of eight proteins to pyrenoids. These included a putative Rubisco-binding linker, carbonic anhydrase, membrane transporter, and uncharacterized GTPase proteins. Notably, most of these proteins were unique to this algal lineage. We suggest a plausible scenario in which pyrenoids in chlorarachniophytes have evolved independently, as their components are not inherited from green algal pyrenoids.

Sperm-specific histone H1 in highly condensed sperm nucleus of Sargassum horneri.
Yu Takeuchi; Shinya Sato; Chikako Nagasato; Taizo Motomura; Shujiro Okuda; Masahiro Kasahara; Fumio Takahashi; Shinya Yoshikawa
Scientific reports, 14, 1, 3387, 3387, 09 Feb. 2024, [International Magazine]
English, Scientific journal, Spermatogenesis is one of the most dramatic changes in cell differentiation. Remarkable chromatin condensation of the nucleus is observed in animal, plant, and algal sperm. Sperm nuclear basic proteins (SNBPs), such as protamine and sperm-specific histone, are involved in chromatin condensation of the sperm nucleus. Among brown algae, sperm of the oogamous Fucales algae have a condensed nucleus. However, the existence of sperm-specific SNBPs in Fucales algae was unclear. Here, we identified linker histone (histone H1) proteins in the sperm and analyzed changes in their gene expression pattern during spermatogenesis in Sargassum horneri. A search of transcriptomic data for histone H1 genes in showed six histone H1 genes, which we named ShH1.1a, ShH1b, ShH1.2, ShH1.3, ShH1.4, and ShH1.5. Analysis of SNBPs using SDS-PAGE and LC-MS/MS showed that sperm nuclei contain histone ShH1.2, ShH1.3, and ShH1.4 in addition to core histones. Both ShH1.2 and ShH1.3 genes were expressed in the vegetative thallus and the male and female receptacles (the organs producing antheridium or oogonium). Meanwhile, the ShH1.4 gene was expressed in the male receptacle but not in the vegetative thallus and female receptacles. From these results, ShH1.4 may be a sperm-specific histone H1 of S. horneri.

Application of CRISPR-Cas9 genome editing by microinjection of gametophytes of Saccharina japonica (Laminariales, Phaeophyceae)
Yuan Shen; Taizo Motomura; Kensuke Ichihara; Yusuke Matsuda; Ko Yoshimura; Chika Kosugi; Chikako Nagasato
Journal of Applied Phycology, Springer Science and Business Media LLC, 27 Mar. 2023
Scientific journal

The baseless mutant links protein phosphatase 2A with basal cell identity in the brown alga Ectocarpus.
Olivier Godfroy; Min Zheng; Haiqin Yao; Agnes Henschen; Akira F Peters; Delphine Scornet; Sebastien Colin; Paolo Ronchi; Katharina Hipp; Chikako Nagasato; Taizo Motomura; J Mark Cock; Susana M Coelho
Development (Cambridge, England), 150, 4, 15 Feb. 2023, [International Magazine]
English, Scientific journal, The first mitotic division of the initial cell is a key event in all multicellular organisms and is associated with the establishment of major developmental axes and cell fates. The brown alga Ectocarpus has a haploid-diploid life cycle that involves the development of two multicellular generations: the sporophyte and the gametophyte. Each generation deploys a distinct developmental programme autonomously from an initial cell, the first cell division of which sets up the future body pattern. Here, we show that mutations in the BASELESS (BAS) gene result in multiple cellular defects during the first cell division and subsequent failure to produce basal structures during both generations. BAS encodes a type B″ regulatory subunit of protein phosphatase 2A (PP2A), and transcriptomic analysis identified potential effector genes that may be involved in determining basal cell fate. The bas mutant phenotype is very similar to that observed in distag (dis) mutants, which lack a functional Tubulin-binding co-factor Cd1 (TBCCd1) protein, indicating that TBCCd1 and PP2A are two essential components of the cellular machinery that regulates the first cell division and mediates basal cell fate determination.

Simultaneous visualization of the actin plate and new cell partition membrane during cytokinesis in the brown alga Sphacelaria rigidula ( Sphacelariales, Phaeophyceae )
Hinako Aoki; Christos Katsaros; Taizo Motomura; Chikako Nagasato
Phycological Research, 10 Jan. 2023
Scientific journal

Assembly and synthesis of the extracellular matrix in brown algae.
Lisa Mazéas; Rina Yonamine; Tristan Barbeyron; Bernard Henrissat; Elodie Drula; Nicolas Terrapon; Chikako Nagasato; Cécile Hervé
Seminars in cell & developmental biology, 17 Mar. 2022, [International Magazine]
English, Scientific journal, In brown algae, the extracellular matrix (ECM) and its constitutive polymers play crucial roles in specialized functions, including algal growth and development. In this review we offer an integrative view of ECM construction in brown algae. We briefly report the chemical composition of its main constituents, and how these are interlinked in a structural model. We examine the ECM assembly at the tissue and cell level, with consideration on its structure in vivo and on the putative subcellular sites for the synthesis of its main constituents. We further discuss the biosynthetic pathways of two major polysaccharides, alginates and sulfated fucans, and the progress made beyond the candidate genes with the biochemical validation of encoded proteins. Key enzymes involved in the elongation of the glycan chains are still unknown and predictions have been made at the gene level. Here, we offer a re-examination of some glycosyltransferases and sulfotransferases from published genomes. Overall, our analysis suggests novel investigations to be performed at both the cellular and biochemical levels. First, to depict the location of polysaccharide structures in tissues. Secondly, to identify putative actors in the ECM synthesis to be functionally studied in the future.

Ultrastructural Observation of Cytokinesis and Plasmodesmata Formation in Brown Algae.
Chikako Nagasato; Rina Yonamine; Taizo Motomura
Methods in molecular biology (Clifton, N.J.), 2382, 253, 264, 2022, [International Magazine]
English, Scientific journal, Similar to land plant cells, brown algal cells possess plasmodesmata with minute cytoplasmic tunnels, which enable the direct connection between adjacent cells. Plasmodesmata are distributed depending on the association of their formation with cytokinesis. Primary plasmodesmata are formed during cytokinesis, while secondary plasmodesmata appear on the cell wall septum following cytokinesis. Typically, the plasmodesmata of brown algae are cylindrical without the penetration of desmotubules from the endoplasmic reticulum, and there are no morphological differences between primary and secondary plasmodesmata. This present chapter describes the observation of cytokinesis and primary plasmodesmata formation in brown algae using electron microscopy as well as the examination of polysaccharide distribution using antibodies and enzyme-gold probes.

Targeted CRISPR-Cas9-based gene knockouts in the model brown alga Ectocarpus.
Yacine Badis; Delphine Scornet; Minori Harada; Céline Caillard; Olivier Godfroy; Morgane Raphalen; Claire M M Gachon; Susana M Coelho; Taizo Motomura; Chikako Nagasato; J Mark Cock
The New phytologist, 231, 5, 2077, 2091, Sep. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal, Brown algae are an important group of multicellular eukaryotes, phylogenetically distinct from both the animal and land plant lineages. Ectocarpus has emerged as a model organism to study diverse aspects of brown algal biology, but this system currently lacks an effective reverse genetics methodology to analyse the functions of selected target genes. Here, we report that mutations at specific target sites are generated following the introduction of CRISPR-Cas9 ribonucleoproteins into Ectocarpus cells, using either biolistics or microinjection as the delivery method. Individuals with mutations affecting the ADENINE PHOSPHORIBOSYL TRANSFERASE (APT) gene were isolated following treatment with 2-fluoroadenine, and this selection system was used to isolate individuals in which mutations had been introduced simultaneously at APT and at a second gene. This double mutation approach could potentially be used to isolate mutants affecting any Ectocarpus gene, providing an effective reverse genetics tool for this model organism. The availability of this tool will significantly enhance the utility of Ectocarpus as a model organism for this ecologically and economically important group of marine organisms. Moreover, the methodology described here should be readily transferable to other brown algal species.

Changes in Cell Wall Structure During Rhizoid Formation of Silvetia babingtonii (Fucales, Phaeophyceae) Zygotes.
Rina Yonamine; Kensuke Ichihara; Shiro Tsuyuzaki; Cécile Hervé; Taizo Motomura; Chikako Nagasato
Journal of phycology, 57, 4, 1356, 1367, Aug. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal, We examined the ultrastructure of the cell wall and immunolocalization of alginates using specific antibodies against M-rich alginates and MG blocks during rhizoid formation in fucoid zygotes, Silvetia babingtonii. The thallus region of 24-h-old zygotes had a cell wall made of three layers with different fiber distribution. In the 12-h-old zygotes, three layers in the thallus were observed before rhizoid formation, namely the inner, middle, and outer layers. During rhizoid elongation, only the inner layer was apparent close to the rhizoid tip area. Immunoelectron microscopy detected M-rich blocks of alginate on the inner half of the cell wall, irrespective of the number of layers in the thallus and rhizoid regions. The MG blocks were seen to cover a slightly wider area than M-rich alginate blocks. It was suggested that parts of M in mannuronan would be rapidly converted to G, and MG-blocks are generated. Transcriptome analysis was performed using 3 -, 10 -, and 24-h-old zygotes after fertilization to examine the relationship between gene expression and alginate synthesis over time. The expression of two mannuronan C5-epimerase homologs that convert mannuronic acid into guluronic acid in alginates was upregulated or downregulated over the course of the examination.

Ultrastructural observations of mitochondrial morphology through the life cycle of the brown alga, Mutiomo cylindricus (Cutleriaceae, Tilopteridales).
Yuan Shen; Taizo Motomura; Chikako Nagasato
Protoplasma, 17 Jun. 2021, [Peer-reviewed], [International Magazine]
English, Scientific journal, Mitochondrial morphology varies according to development and the physiological conditions of the cell. Here, we performed electron tomography using serial sections to analyze the number, individual volume, and morphological complexity of mitochondria in the cells across two generations in the life cycle of the brown alga Mutimo cylindricus. This species shows a heteromorphic alternation of generations between the macroscopic gametophyte and the crustose sporophyte during its life cycle and displays anisogamous sexual reproduction. We observed the mitochondria in the vegetative cells of gametophytes and sporophytes to mainly show tubular or discoidal shapes with high morphological complexity. The morphology of the mitochondria in the male and female gametes changed to a nearly spherical or oval shape from a tubular or discoidal shape before release. In this species, degradation of the paternal mitochondria was observed in the zygote 2 h after fertilization. Morphological changes in the mitochondria were not observed until 6 h after fertilization. Twenty-four-hour-old zygotes before and after cytokinesis showed a similar number of mitochondria as 6-h-old zygotes; however, the volume and morphological complexity increased. The results indicated that the maternal mitochondria did not undergo fission or fusion until this stage. Based on the analysis results of the number and total volume of mitochondria before and after the release of the gametes, it is possible that the mitochondria in the female gametes fuse immediately before release.

Detecting no natural hybridization and predicting range overlap in Saccharina angustata and Saccharina japonica
Jie Zhang; Norishige Yotsukura; Alexander Jueterbock; Zi-Min Hu; Jorge Assis; Chikako Nagasato; Jianting Yao; Delin Duan
Journal of Applied Phycology, 33, 1, 693, 702, Springer Science and Business Media B.V., 01 Feb. 2021
English, Scientific journal

Cytoplasmic inheritance of mitochondria and chloroplasts in the anisogamous brown alga Mutimo cylindricus (Phaeophyceae).
Yuan Shen; Toyoki Iwao; Taizo Motomura; Chikako Nagasato
Protoplasma, 29 Aug. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, Based on the morphology of gametes, sexual reproduction in brown algae is usually classified into three types: isogamy, anisogamy, and oogamy. In isogamy, chloroplasts and chloroplast DNA (chlDNA) in the sporophyte cells are inherited biparentally, while mitochondria (or mitochondrial DNA, mtDNA) is inherited maternally. In oogamy, chloroplasts and mitochondria are inherited maternally. However, the patterns of mitochondrial and chloroplast inheritance in anisogamy have not been clarified. Here, we examined derivation of mtDNA and chlDNA in the zygotes through strain-specific PCR analysis using primers based on single nucleotide polymorphism in the anisogamous brown alga Mutimo cylindricus. In 20-day-old sporophytes after fertilization, mtDNA and chlDNA derived from female gametes were detected, thus confirming the maternal inheritance of both organelles. Additionally, the behavior of mitochondria and chloroplasts in the zygotes was analyzed by examining the consecutive serial sections using transmission electron microscopy. Male mitochondria were isolated or compartmentalized by a double-membrane and then completely digested into a multivesicular structure 2 h after fertilization. Meanwhile, male chloroplasts with eyespots were observed even in 4-day-old, seven-celled sporophytes. The final fate of male chloroplasts could not be traced. Organelle DNA copy number was also examined in female and male gametes. The DNA copy number per chloroplast and mitochondria in male gametes was lower compared with female organelles. The degree of difference is bigger in mtDNA. Thus, changes in different morphology and DNA amount indicate that maternal inheritance of mitochondria and chloroplasts in this species may be based on different processes and timing after fertilization.

Organelle inheritance and genome architecture variation in isogamous brown algae.
Ji Won Choi; Louis Graf; Akira F Peters; J Mark Cock; Koki Nishitsuji; Asuka Arimoto; Eiichi Shoguchi; Chikako Nagasato; Chang Geun Choi; Hwan Su Yoon
Scientific reports, 10, 1, 2048, 2048, 06 Feb. 2020, [Peer-reviewed], [International Magazine]
English, Scientific journal, Among the brown algal lineages, Ectocarpales species have isogamous fertilization in which male and female gametes are morphologically similar. In contrast, female gametes are much larger than male gametes in the oogamous species found in many other brown algal lineages. It has been reported that the plastids of isogamous species are biparentally inherited whereas the plastids of oogamous species are maternally inherited. In contrast, in both isogamous and oogamous species, the mitochondria are usually inherited maternally. To investigate whether there is any relationship between the modes of inheritance and organellar genome architecture, we sequenced six plastid genomes (ptDNA) and two mitochondrial genomes (mtDNA) of isogamous species from the Ectocarpales and compared them with previously sequenced organellar genomes. We found that the biparentally inherited ptDNAs of isogamous species presented distinctive structural rearrangements whereas maternally inherited ptDNAs of oogamous species showed no rearrangements. Our analysis permits the hypothesis that structural rearrangements in ptDNAs may be a consequence of the mode of inheritance.

Phylogeographic diversification and postglacial range dynamics shed light on the conservation of the kelp Saccharina japonica.
Jie Zhang; Jianting Yao; Zi-Min Hu; Alexander Jueterbock; Norishige Yotsukura; Tatiana N Krupnova; Chikako Nagasato; Delin Duan
Evolutionary applications, 12, 4, 791, 803, Apr. 2019, [International Magazine]
English, Scientific journal, Studies of postglacial range shifts could enhance our understanding of seaweed species' responses to climate change and hence facilitate the conservation of natural resources. However, the distribution dynamics and phylogeographic diversification of the commercially and ecologically important kelp Saccharina japonica in the Northwest Pacific (NWP) are still poorly surveyed. In this study, we analyzed the evolutionary history of S. japonica using two mitochondrial markers and 24 nuclear microsatellites. A STRUCTURE analysis revealed two partially isolated lineages: lineage H, which is scattered along the coast of Japan; and lineage P, which occurs along the west coast of the Japan Sea. Ecological niche modeling projections to the Last Glacial Maximum (LGM) revealed that the southern coasts of the Japan Sea and the Pacific side of the Oshima and Honshu Peninsulas provided the most suitable habitats for S. japonica, implying that these regions served as ancient refugia during the LGM. Ancient isolation in different refugia may explain the observed divergence between lineages P and H. An approximate Bayesian computation analysis indicated that the two lineages experienced post-LGM range expansion and that postglacial secondary contact occurred in Sakhalin. Model projections into the year 2,100 predicted that S. japonica will shift northwards and lose its genetic diversity center on the Oshima Peninsula in Hokkaido and Shimokita Peninsula in Honshu. The range shifts and evolutionary history of S. japonica improve our understanding of how climate change impacted the distribution range and diversity of this species and provide useful information for the conservation of natural resources under ongoing environmental change in the NWP.

Unusual patterns of mitochondrial inheritance in the brown alga Ectocarpus.
Mignerot, L; Nagasato, C; Peters, A; Perrineau, M. M; Scornet, D; Pontheaux, F; Djema, W; Roze, D; Motomura. T; Coelho, S. M; Cock, J. M
Molecular Biology and Evolution, 2019, [Peer-reviewed]

Quantification of laminarialean zoospores in seawater by real‐time PCR.
Nagasato, C; Kawamoto, H; Tomioka, T; Tsuyuzaki, S; Kosugi, C; Kato, T; Motomura, T
Phycological Research, 2019, [Peer-reviewed]

The role of egg flagella in the settlement and development of zygotes in two Saccharina species.
Klochkova, T. A; Motomura, T; Nagasato, C; Klimova; A. V; Kim, G. H
Phycologia, 58, 2, 145, 153, 2019, [Peer-reviewed]

Effect of brefeldin A and the dynamics of the actin plate on cytokinesis of zygotes in the brown alga, Silvetia babingtonii (Fucales, Phaeophyceae).
Nagasato, C; Motomura, T
European Journal of Phycology., 54, 1, 26, 38, 2019, [Peer-reviewed]

DISTAG/TBCCD1 is required for basal cell fate determination in Ectocarpus
Olivier Godfroy; Toshiki Uji; Chikako Nagasato; Agnieszka P. Lipinska; Delphine Scornet; Akira F. Peters; Komlan Avia; Sebastien Colin; Laure Mignerot; Taizo Motomura; J. Mark Cock; Susana M. Coelho
Plant Cell, 29, 12, 3102, 3122, 01 Dec. 2017, [Peer-reviewed]
English, Scientific journal

Calcium Control of the Sign of Phototaxis in Brown Algal Gametes of Mutimo cylindricus
Nana Kinoshita; Chikako Nagasato; Taizo Motomura
PHOTOCHEMISTRY AND PHOTOBIOLOGY, 93, 5, 1216, 1223, Oct. 2017, [Peer-reviewed]
English, Scientific journal

Branch regeneration induced by sever damage in the brown alga Dictyota dichotoma (dictyotales, phaeophyceae)
Atsuko Tanaka; Yoichiro Hoshino; Chikako Nagasato; Taizo Motomura
PROTOPLASMA, 254, 3, 1341, 1351, May 2017, [Peer-reviewed]
English, Scientific journal

Phototaxis and chemotaxis of brown algal swarmers
Nana Kinoshita; Chikako Nagasato; Taizo Motomura
JOURNAL OF PLANT RESEARCH, 130, 3, 443, 453, May 2017, [Peer-reviewed]
English

INTERCELLULAR TRANSLOCATION OF MOLECULES VIA PLASMODESMATA IN THE MULTISERIATE FILAMENTOUS BROWN ALGA, HALOPTERIS CONGESTA (SPHACELARIALES, PHAEOPHYCEAE)
Chikako Nagasato; Atsuko Tanaka; Toshiaki Ito; Christos Katsaros; Taizo Motomura
JOURNAL OF PHYCOLOGY, 53, 2, 333, 341, Apr. 2017, [Peer-reviewed]
English, Scientific journal

Chemotactic movement in sperm of the oogamous brown algae, Saccharina japonica and Fucus distichus
Nana Kinoshita; Chikako Nagasato; Taizo Motomura
PROTOPLASMA, 254, 1, 547, 555, Jan. 2017, [Peer-reviewed]
English, Scientific journal

Mitotic spindle formation in Triparma laevis NIES-2565(Parmales, Heterokontophyta)
Kazumasa Yamada; Chikako Nagasato; Taizo Motomura; Mutsuo Ichinomiya; Akira Kuwata; Mitsunobu Kamiya; Kaori Ohki; Shinya Yoshikawa
PROTOPLASMA, 254, 1, 461, 471, Jan. 2017, [Peer-reviewed]
English, Scientific journal

Distribution of alginate and cellulose and regulatory role of calcium in the cell wall of the brown alga Ectocarpus siliculosus (Ectocarpales, Phaeophyceae)
Makoto Terauchi; Chikako Nagasato; Akira Inoue; Toshiaki Ito; Taizo Motomura
PLANTA, 244, 2, 361, 377, Aug. 2016, [Peer-reviewed]
English, Scientific journal

Thylakoid luminal theta-carbonic anhydrase critical for growth and photosynthesis in the marine diatom Phaeodactylum tricornutum
Sae Kikutani; Kensuke Nakajima; Chikako Nagasato; Yoshinori Tsuji; Ai Miyatake; Yusuke Matsuda
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 113, 35, 9828, 9833, Aug. 2016, [Peer-reviewed]
English, Scientific journal

Flagellar waveforms of gametes in the brown alga Ectocarpus siliculosus
Nana Kinoshita; Kogiku Shiba; Kazuo Inaba; Gang Fu; Chikako Nagasato; Taizo Motomura
EUROPEAN JOURNAL OF PHYCOLOGY, 51, 2, 139, 148, May 2016, [Peer-reviewed]
English, Scientific journal

Ubiquitous distribution of helmchrome in phototactic swarmers of the stramenopiles
Gang Fu; Chikako Nagasato; Takahiro Yamagishi; Hiroshi Kawai; Kazuo Okuda; Yoshitake Takao; Takeo Horiguchi; Taizo Motomura
PROTOPLASMA, 253, 3, 929, 941, May 2016, [Peer-reviewed]
English, Scientific journal

Formation of primary intercellular connections in multicellular algae. (in Japanese)
Nagasato, C; Terauchi, M; Motomura, T
Microscopy, 51, 3, 140, 144, 日本顕微鏡学会, 2016, [Peer-reviewed]
Japanese

Chemotaxis in the anisogamous brown alga Mutimo cylindricus (Cutleriaceae, Tilopteridales)
Nana Kinoshita; Chikako Nagasato; Atsuko Tanaka; Taizo Motomura
PHYCOLOGIA, 55, 4, 359, 364, 2016, [Peer-reviewed]
English, Scientific journal

Ultrastructural analysis of siliceous cell wall regeneration in the stramenopile Triparma laevis (Parmales, Bolidophyceae)
Kazumasa Yamada; Shinya Yoshikawa; Kaori Ohki; Mutsuo Ichinomiya; Akira Kuwata; Taizo Motomura; Chikako Nagasato
PHYCOLOGIA, 55, 5, 602, 609, 2016, [Peer-reviewed]
English, Scientific journal

Phylogeographic data revealed shallow genetic structure in the kelp Saccharina japonica (Laminariales, Phaeophyta)
Jie Zhang; Jian-Ting Yao; Zhong-Min Sun; Gang Fu; Dmitry A. Galanin; Chikako Nagasato; Taizo Motomura; Zi-Min Hu; De-Lin Duan
BMC EVOLUTIONARY BIOLOGY, 15, Nov. 2015, [Peer-reviewed]
English, Scientific journal

Development and function of plasmodesmata in zygotes of Fucus distichus
Chikako Nagasato; Makoto Terauchi; Atsuko Tanaka; Taizo Motomura
BOTANICA MARINA, 58, 3, 229, 238, Jun. 2015, [Peer-reviewed]
English, Scientific journal

SPERMATOGENESIS AND AUXOSPORE STRUCTURE IN THE MULTIPOLAR CENTRIC DIATOM HYDROSERA
Masahiko Idei; Shinya Sato; Chikako Nagasato; Taizo Motomura; Kensuke Toyoda; Tamotsu Nagumo; David G. Mann
JOURNAL OF PHYCOLOGY, 51, 1, 144, 158, Feb. 2015, [Peer-reviewed]
English, Scientific journal

ULTRASTRUCTURAL ANALYSIS OF MITOSIS IN TRIPARMA LAEVIS (PARMALES, HETEROKONTOPHYTA)
Kazumasa Yamada; Chikako Nagasato; Taizo Motomura; Mutsuo Ichinomiya; Akira Kuwata; Mitsunobu Kamiya; Kaori Ohki; Shinya Yoshikawa
EUROPEAN JOURNAL OF PHYCOLOGY, 50, 155, 156, 2015, [Peer-reviewed]
English

Plasmodesmata of brown algae
Makoto Terauchi; Chikako Nagasato; Taizo Motomura
JOURNAL OF PLANT RESEARCH, 128, 1, 7, 15, Jan. 2015, [Peer-reviewed]
English

Identification of three proteins involved in fertilization and parthenogenetic development of a brown alga, Scytosiphon lomentaria
Jong Won Han; Tatyana A. Klochkova; Junbo Shim; Chikako Nagasato; Taizo Motomura; Gwang Hoon Kim
PLANTA, 240, 6, 1253, 1267, Dec. 2014, [Peer-reviewed]
English, Scientific journal

Electron tomographic analysis of cytokinesis in the brown alga Silvetia babingtonii (Fucales, Phaeophyceae)
Chikako Nagasato; Naoko Kajimura; Makoto Terauchi; Yoshinobu Mineyuki; Taizo Motomura
PROTOPLASMA, 251, 6, 1347, 1357, Nov. 2014, [Peer-reviewed]
English, Scientific journal

Proteomics Analysis of Heterogeneous Flagella in Brown Algae (Stramenopiles)
Gang Fu; Chikako Nagasato; Seiko Oka; J. Mark Cock; Taizo Motomura
PROTIST, 165, 5, 662, 675, Sep. 2014, [Peer-reviewed]
English, Scientific journal

Cell Cycle and Nucleomorph Division in Pyrenomonas helgolandii (Cryptophyta)
Tomonori Sato; Chikako Nagasato; Yoshiaki Hara; Taizo Motomura
PROTIST, 165, 2, 113, 122, Mar. 2014, [Peer-reviewed]
English, Scientific journal

Cold-tolerant strain of Haematococcus pluvialis (Haematococcaceae, Chlorophyta) from Blomstrandhalvoya (Svalbard)
Tatyana A. Klochkova; Min Seok Kwak; Jong Won Han; Taizo Motomura; Chikako Nagasato; Gwang Hoon Kim
ALGAE, 28, 2, 185, 192, Jun. 2013, [Peer-reviewed]
English, Scientific journal

Ultrastructural analysis of flagellar development in plurilocular sporangia of Ectocarpus siliculosus (Phaeophyceae)
Gang Fu; Chikako Nagasato; Toshiaki Ito; Dieter G. Müller; Taizo Motomura
Protoplasma, 250, 1, 261, 272, 2013, [Peer-reviewed]
English, Scientific journal

Ultrastructural study of plasmodesmata in the brown alga Dictyota dichotoma (Dictyotales, Phaeophyceae)
Makoto Terauchi; Chikako Nagasato; Naoko Kajimura; Yoshinobu Mineyuki; Kazuo Okuda; Christos Katsaros; Taizo Motomura
PLANTA, 236, 4, 1013, 1026, Oct. 2012, [Peer-reviewed]
English, Scientific journal

The Ectocarpus Genome and Brown Algal Genomics. The Ectocarpus Genome Consortium.
J. Mark Cock; Lieven Sterck; Sophia Ahmed; Andrew E. Allen; Grigoris Amoutzias; Veronique Anthouard; François Artiguenave; Alok Arun; Jean-Marc Aury; Jonathan H. Badger; Bank Beszteri; Kenny Billiau; Eric Bonnet; John H. Bothwell; Chris Bowler; Catherine Boyen; Colin Brownlee; Carl J. Carrano; Bénédicte Charrier; Ga Youn Cho; Susana M. Coelho; Jonas Collén; Gildas Le Corguillé; Erwan Corre; Laurence Dartevelle; Corinne Da Silva; Ludovic Delage; Nicolas Delaroque; Simon M. Dittami; Sylvie Doulbeau; Marek Elias; Garry Farnham; Claire M.M. Gachon; Olivier Godfroy; Bernhard Gschloessl; Svenja Heesch; Kamel Jabbari; Claire Jubin; Hiroshi Kawai; Kei Kimura; Bernard Kloareg; Frithjof C. Küpper; Daniel Lang; Aude Le Bail; Rémy Luthringer; Catherine Leblanc; Patrice Lerouge; Martin Lohr; Pascal J. Lopez; Nicolas Macaisne; Cindy Martens; Florian Maumus; Gurvan Michel; Diego Miranda-Saavedra; Julia Morales; Hervé Moreau; Taizo Motomura; Chikako Nagasato; Carolyn A. Napoli; David R. Nelson; Pi Nyvall-Collén; Akira F. Peters; Cyril Pommier; Philippe Potin; Julie Poulain; Hadi Quesneville; Betsy Read; Stefan A. Rensing; Andrés Ritter; Sylvie Rousvoal; Manoj Samanta; Gaelle Samson; Declan C. Schroeder; Delphine Scornet; Béatrice Ségurens; Martina Strittmatter; Thierry Tonon; James W. Tregear; Klaus Valentin; Peter Von Dassow; Takahiro Yamagishi; Pierre Rouzé; Yves Van de Peer; Patrick Wincker
Advances in Botanical Research, 64, 141, 184, 2012
English, Scientific journal

Comparative Immunofluorescence and Ultrastructural Analysis of Microtubule Organization in Uronema sp., Klebsormidium flaccidum, K. subtilissimum, Stichococcus bacillaris and S. chloranthus (Chlorophyta)
Christos I. Katsaros; Vasilios Varvarigos; Claire M. M. Gachon; Jerry Brand; Taizo Motomura; Chikako Nagasato; Frithjof C. Kuepper
PROTIST, 162, 2, 315, 331, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Sperm Mitochondrial DNA Elimination in the Zygote of the Oogamous Brown Alga Undaria pinnatifida (Laminariales, Phaeophyceae)
Kei Kimura; Chikako Nagasato; Shinya Uwai; Taizo Motomura
CYTOLOGIA, 75, 4, 353, 361, Dec. 2010, [Peer-reviewed]
English, Scientific journal

Membrane fusion process and assembly of cell wall during cytokinesis in the brown alga, Silvetia babingtonii (Fucales, Phaeophyceae)
Chikako Nagasato; Akira Inoue; Masashi Mizuno; Kazuki Kanazawa; Takao Ojima; Kazuo Okuda; Taizo Motomura
PLANTA, 232, 2, 287, 298, Jul. 2010, [Peer-reviewed]
English

Research note: Analysis of expressed sequence tags from the chrysophycean alga Ochromonas danica (Heterokontophyta)
Makoto Terauchi; Atsushi Kato; Chikako Nagasato; Taizo Motomura
PHYCOLOGICAL RESEARCH, 58, 3, 217, 221, Jul. 2010, [Peer-reviewed]
English, Scientific journal

The Ectocarpus genome and the independent evolution of multicellularity in brown algae
J. Mark Cock; Lieven Sterck; Pierre Rouze; Delphine Scornet; Andrew E. Allen; Grigoris Amoutzias; Veronique Anthouard; Francois Artiguenave; Jean-Marc Aury; Jonathan H. Badger; Bank Beszteri; Kenny Billiau; Eric Bonnet; John H. Bothwell; Chris Bowler; Catherine Boyen; Colin Brownlee; Carl J. Carrano; Benedicte Charrier; Ga Youn Cho; Susana M. Coelho; Jonas Collen; Erwan Corre; Corinne Da Silva; Ludovic Delage; Nicolas Delaroque; Simon M. Dittami; Sylvie Doulbeau; Marek Elias; Garry Farnham; Claire M. M. Gachon; Bernhard Gschloessl; Svenja Heesch; Kamel Jabbari; Claire Jubin; Hiroshi Kawai; Kei Kimura; Bernard Kloareg; Frithjof C. Kuepper; Daniel Lang; Aude Le Bail; Catherine Leblanc; Patrice Lerouge; Martin Lohr; Pascal J. Lopez; Cindy Martens; Florian Maumus; Gurvan Michel; Diego Miranda-Saavedra; Julia Morales; Herve Moreau; Taizo Motomura; Chikako Nagasato; Carolyn A. Napoli; David R. Nelson; Pi Nyvall-Collen; Akira F. Peters; Cyril Pommier; Philippe Potin; Julie Poulain; Hadi Quesneville; Betsy Read; Stefan A. Rensing; Andres Ritter; Sylvie Rousvoal; Manoj Samanta; Gaelle Samson; Declan C. Schroeder; Beatrice Segurens; Martina Strittmatter; Thierry Tonon; James W. Tregear; Klaus Valentin; Peter von Dassow; Takahiro Yamagishi; Yves Van de Peer; Patrick Wincker
NATURE, 465, 7298, 617, 621, Jun. 2010, [Peer-reviewed]
English, Scientific journal

Cytoplasmic inheritance of organelles in brown algae
Taizo Motomura; Chikako Nagasato; Kei Kimura
JOURNAL OF PLANT RESEARCH, 123, 2, 185, 192, Mar. 2010, [Peer-reviewed]
English, Scientific journal

DISAPPEARANCE OF MALE MITOCHONDRIAL DNA AFTER THE FOUR-CELL STAGE IN SPOROPHYTES OF THE ISOGAMOUS BROWN ALGA SCYTOSIPHON LOMENTARIA (SCYTOSIPHONACEAE, PHAEOPHYCEAE)
Kei Kimura; Chikako Nagasato; Kazuhiro Kogame; Taizo Motomura
JOURNAL OF PHYCOLOGY, 46, 1, 143, 152, Feb. 2010, [Peer-reviewed]
English, Scientific journal

石油系燃料油汚染土壌のバイオレメディエーション－特に環境微生物学的なアプローチ－
北山茂一; 原宏哉; 岩城美朝; 長里千香子; 本村泰三; 遠山忠; チャンヨンチョル; 菊池慎太郎
環境技術, 38, 276, 282, 01 Oct. 2009, [Peer-reviewed]
Japanese, Scientific journal

NOVEL PROTEINS COMPRISING THE STRAMENOPILE TRIPARTITE MASTIGONEME IN OCHROMONAS DANICA (CHRYSOPHYCEAE)
Takahiro Yamagishi; Taizo Motomura; Chikako Nagasato; Hiroshi Kawai
JOURNAL OF PHYCOLOGY, 45, 5, 1110, 1115, Oct. 2009, [Peer-reviewed]
English, Scientific journal

Distribution and phylogeny of the blue light receptors aureochromes in eukaryotes
Mie Ishikawa; Fumio Takahashi; Hisayoshi Nozaki; Chikako Nagasato; Taizo Motomura; Hironao Kataoka
PLANTA, 230, 3, 543, 552, Aug. 2009, [Peer-reviewed]
English, Scientific journal

Ultrastructure of mitosis and cytokinesis during spermatogenesis in Porphyra yezoensis (Bangiales, Rhodophyta)
Chika Ueki; Chikako Nagasato; Taizo Motomura; Naotsune Saga
BOTANICA MARINA, 52, 2, 129, 139, Apr. 2009, [Peer-reviewed]
English, Scientific journal

EFFECT OF LATRUNCULIN B AND BREFELDIN A ON CYTOKINESIS IN THE BROWN ALGA SCYTOSIPHON LOMENTARIA (SCYTOSIPHONALES, PHAEOPHYCEAE)
Chikako Nagasato; Taizo Motomura
JOURNAL OF PHYCOLOGY, 45, 2, 404, 412, Apr. 2009, [Peer-reviewed]
English, Scientific journal

Diaphragm development in cytokinetic vegetative cells of brown algae
Christos Katsaros; Taizo Motomura; Chikako Nagasato; Basil Galatis
BOTANICA MARINA, 52, 2, 150, 161, Apr. 2009, [Peer-reviewed]
English, Scientific journal

Functional and non-functional spindle formation affecting mitosis and cytokinesis in Fucus distichus zygotes: the role of the centrosome
Taizo Motomura; Chikako Nagasato
BOTANICA MARINA, 52, 2, 140, 149, Apr. 2009, [Peer-reviewed]
English, Scientific journal

Reexamination of the pit plugs and the characteristic membranous structures in Porphyra yezoensis (Bangiales, Rhodophyta)
Chika Ueki; Chikako Nagasato; Taizo Motomura; Naotsune Saga
PHYCOLOGIA, 47, 1, 5, 11, Jan. 2008, [Peer-reviewed]
English, Scientific journal

Re-examination of ultrastructures of the stellate chloroplast organization in brown algae: Structure and development of pyrenoids
Atsuko Tanaka; Chikako Nagasato; Shinya Uwai; Taizo Motomura; Hiroshi Kawai
PHYCOLOGICAL RESEARCH, 55, 3, 203, 213, Sep. 2007, [Peer-reviewed]
English, Scientific journal

A tubular mastigoneme-related protein, Ocm1, isolated from the flagellum of a chromophyte alga, Ochromonas danica
Takahiro Yamagishi; Taizo Motomura; Chikako Nagasato; Atsushi Kato; Hiroshi Kawai
JOURNAL OF PHYCOLOGY, 43, 3, 519, 527, Jun. 2007, [Peer-reviewed]
English, Scientific journal

Ultrastructural and immunocytological studies on the rhizoplast in the chrysophycean alga Ochromonas danica
Chihiro Uemori; Chikako Nagasato; Atsushi Kato; Taizo Motomura
PHYCOLOGICAL RESEARCH, 54, 2, 133, 139, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Inheritance of mitochondrial and chloroplast genomes in the isogamous brown alga Scytosiphon lomentaria (Phaeophyceae)
Y Kato; K Kogame; C Nagasato; T Motomura
PHYCOLOGICAL RESEARCH, 54, 1, 65, 71, Mar. 2006, [Peer-reviewed]
English, Scientific journal

Behavior and function of paternally inherited centrioles in brown algal zygotes
C Nagasato
JOURNAL OF PLANT RESEARCH, 118, 6, 361, 369, Dec. 2005, [Peer-reviewed]
English, Scientific journal

Life history and molecular phylogenetic relationships of Asterocladon interjectum sp nov (Phaeophyceae)
S Uwai; C Nagasato; T Motomura; K Kogame
EUROPEAN JOURNAL OF PHYCOLOGY, 40, 2, 179, 194, May 2005, [Peer-reviewed]
English, Scientific journal

Destruction of maternal Centrioles during fertilization of the brown alga, Scytosiphon iomentaria (Scytosiphonales, Phaeophyceae)
C Nagasato; T Motomura
CELL MOTILITY AND THE CYTOSKELETON, 59, 2, 109, 118, Oct. 2004, [Peer-reviewed]
English, Scientific journal

Characterization of centrin genes from Ochromonas danica (Chrysophyceae) and Scytosiphon lomentaria (Phaeophyceae)
C Nagasato; C Uemori; A Kato; T Motomura
PHYCOLOGICAL RESEARCH, 52, 3, 266, 272, Sep. 2004, [Peer-reviewed]
English, Scientific journal

The first spindle formation in brown algal zygotes
T Motomura; C Nagasato
HYDROBIOLOGIA, 512, 1-3, 171, 176, Jan. 2004, [Peer-reviewed]
English, Scientific journal

Nuclear histone proteins of gametes in brown algae. The Japanese Journal of Phycology (Sorui) 52 (supplement issue)
Yoshikawa S; Nagasato C; Makino Y; Murakami A; Kawai H; Ichimura T; Motomura T
Japanese Journal of Phycology (Sorui), 52, 123, 127, 2004, [Peer-reviewed]

Pyrenoid formation associated with the cell cycle in the brown alga, Scytosiphon lomentaria (Scytosiphonales, Phaeophyceae)
Chikako Nagasato; Shinya Yoshikawa; Masakane Yamashita; Hiroshi Kawai; Taizo Motomura
Journal of Phycology, 39, 6, 1172, 1180, Dec. 2003, [Peer-reviewed]
English, Scientific journal

Morphological changes of sperm nuclei during spermatogenesis in the brown alga Cystoseira hakodatensis (Fucales, Phaeophyceae)
Shinya Yoshikawa; Chikako Nagasato; Terunobu Ichimura; Taizo Motomura
Phycological Research, 51, 2, 77, 82, Blackwell Publishing, 2003, [Peer-reviewed]
English, Scientific journal

New pyrenoid formation in the brown alga, Scytosiphon lomentaria (Scytosiphonales, Phaeophyceae)
C Nagasato; T Motomura
JOURNAL OF PHYCOLOGY, 38, 4, 800, 806, Aug. 2002, [Peer-reviewed]
English, Scientific journal

Influence of the centrosome in cytokinesis of brown algae: polyspermic zygotes of Scytosiphon lomentaria (Scytosiphonales, Phaeophyceae)
C Nagasato; T Motomura
JOURNAL OF CELL SCIENCE, 115, 12, 2541, 2548, Jun. 2002, [Peer-reviewed]
English, Scientific journal

Nuclear histone proteins of gametes in an oogamous and two isogamous brown algae
Shinya Yoshikawa; Chikako Nagasato; Yumiko Makino; Akio Murakami; Hiroshi Kawai; Terunobu Ichimura; Taizo Motomura
Journal of Phycology, 38, 2, 318, 324, 01 Jan. 2002, [Peer-reviewed]
English, Scientific journal

Ultrastructural study on mitosis and cytokinesis in Scytosiphon lomentaria zygotes (Scytosiphonales, Phaeophyceae) by freeze-substitution
C Nagasato; T Motomura
PROTOPLASMA, 219, 3-4, 140, 149, 2002, [Peer-reviewed]
English, Scientific journal

Degeneration and extrusion of nuclei during oogenesis in Silvetia babingtonii, Cystoseira hakodatensis and Sargassum confusum (Fucales, Phaeophyceae)
C Nagasato; T Motomura; T Ichimura
PHYCOLOGIA, 40, 5, 411, 420, Sep. 2001, [Peer-reviewed]
English, Scientific journal

Transient localization of r-tubulin around the centrioles in the nuclear division of Boergesenia forbesii (Siphonocladales, Chlorophyta).
Motomura T; Nagasato C; Komeda Y; Okuda K
Journal of Phycology, 37, 783, 792, 2001, [Peer-reviewed]

Spindle formation in karyogamy-blocked zygotes of the isogamous brown alga Scytosiphon lomentaria (Scytosiphonales, Phaeophyceae)
C Nagasato; T Motomura; T Ichimura
EUROPEAN JOURNAL OF PHYCOLOGY, 35, 4, 339, 347, Nov. 2000, [Peer-reviewed]
English, Scientific journal

Parthenogenesis and abnormal mitosis in unfertilized eggs of Fucus distichtus (Fucales, Phaeophyceae)
C Nagasato; T Motomura; T Ichimura
PHYCOLOGIA, 39, 2, 163, 166, Mar. 2000, [Peer-reviewed]
English, Scientific journal

Karyogamy block by heat stress in the fertilization of brown algae
C Nagasato; T Motomura; T Ichimura
JOURNAL OF PHYCOLOGY, 35, 6, 1246, 1252, Dec. 1999, [Peer-reviewed]
English, Scientific journal

Influence of centriole behavior on the first spindle formation in zygotes of the brown alga Fucus distichus (Fucales, Phaeophyceae)
C Nagasato; T Motomura; T Ichimura
DEVELOPMENTAL BIOLOGY, 208, 1, 200, 209, Apr. 1999, [Peer-reviewed]
English, Scientific journal

Selective disappearance of maternal centrioles after fertilization in the anisogamous brown alga Cutleria cylindrica (Cutleriales, Phaeophyceae): Paternal inheritance of centrioles is universal in the brown algae
Chikako Nagasato; Taizo Motomura; Terunobu Ichimura
Phycological Research, 46, 3, 191, 198, Blackwell Publishing, 1998, [Peer-reviewed]
English, Scientific journal

Immunolocalization of centrin during fertilization and the first cell cycle in Fucus distichus and Pelvetia compressa (Fucales, Phaeophyceae)
Bisgrove, SR; C Nagasato; T Motomura; DL Kropf
JOURNAL OF PHYCOLOGY, 33, 5, 823, 829, Oct. 1997, [Peer-reviewed]
English, Scientific journal

褐藻ワカメとセイヨウハバノリの光屈性と葉緑体定位運動
日山津奈美; 加藤伊桜里; 長里千香子; 小亀一弘; 吉川伸哉, 藻類, 73, 1, 2025

パルマ藻のプレート形成
山田和正; 桂大貴; 佐藤晋也; 長里千香子; 本村泰三; 一宮睦雄; 桑田晃; 吉川伸哉, Diatom, 31, 61, 25 Dec. 2015
Japanese

パルマ藻Triparma laevisの細胞外被形成過程の微細構造解析
山田和正; 桂大貴; 佐藤晋也; 神谷充伸; 大城香; 一宮睦雄; 桑田晃; 長里千香子; 本村泰三; 吉川伸哉, 日本植物学会大会研究発表記録, 79th, 169, 01 Sep. 2015
Japanese

パルマ藻Triparma laevisの珪酸質殻構築過程の形態学的解析
山田和正; 桂大貴; 佐藤晋也; 神谷充伸; 一宮睦雄; 桑田晃; 長里千香子; 本村泰三; 大城香; 吉川伸哉, 藻類, 63, 1, 76, 10 Mar. 2015
Japanese

パルマ藻Triparma laevisの細胞内微細構造と核分裂様式
山田和正; 長里千香子; 本村泰三; 一宮睦雄; 桑田晃; 神谷充伸; 大城香; 吉川伸哉, 藻類, 62, 1, 52, 10 Mar. 2014
Japanese

ULTRASTRUCTURAL STUDY OF FLAGELLAR APPARATUS AND ANALYSIS OF FLAGELLAR MOTION IN BROWN ALGAE
N. Kinoshita; G. Fu; T. Ito; C. Nagasato; T. Motomura, PHYCOLOGIA, 52, 4, 54, 54, Jul. 2013
English, Summary international conference

CONTRIBUTION OF CALCIUM TO THE CELL WALL STRUCTURE IN THE BROWN ALGA, ECTOCARPUS SILICULOSUS
C. Nagasato; M. Terauchi; T. Motomura, PHYCOLOGIA, 52, 4, 75, 76, Jul. 2013
English, Summary international conference

THREE-DIMENSIONAL ANALYSIS OF TRANSIENT MEMBRANE COMPARTMENT DURING CYTOKINESIS IN BROWN ALGA, SILVETIA BABINGTONII (FUCALES, PHAEOPHYCEAE) BY ELECTRON TOMOGRAPHY
Chikako Nagasato; Naoko Kajimura; Makoto Terauchi; Yoshinobu Mineyuki; Taizo Motomura, EUROPEAN JOURNAL OF PHYCOLOGY, 46, 143, 143, 2011
English, Summary international conference

DIFFERENSE OF ELIMINATION TIMING IN MALE MITOCHONDRIA AND MITOCHONDRIAL DNA AFTER FERTILIZATION BETWEEN ISOGAMOUS AND OOGAMOUS BROWN ALGAE
K. Kimura; K. Kogame; S. Uwai; C. Nagasato; T. Motomura, PHYCOLOGIA, 48, 4, 62, 62, Jul. 2009
English, Summary international conference

THE EST ANALYSIS AND FUNDAMENTAL EXPERIMENT FOR GENE TRANSFORMATION IN CHRYSOPHYCEAN ALGA OCHROMONAS DANICA
M. Terauchi; A. Kato; C. Nagasato; T. Motomura, PHYCOLOGIA, 48, 4, 129, 129, Jul. 2009
English, Summary international conference

MEMBRANE FUSION DURING CYTOKINESIS OF BROWN ALGAE, FUCUS DISTICHUS AND SILVETIA BABINGTONII (FUCALES, PHAEOPHYCEAE)
C. Nagasato; A. Inoue; T. Ojima; K. Okuda; T. Motomura, PHYCOLOGIA, 48, 4, 89, 89, Jul. 2009
English, Summary international conference

AUREOCHROME, newly found in Vaucheria is the common and intrinsic blue light receptor of Stramenopile
Chikako Nagasato; Taizo Motomura; Hironao Kataoka, PLANT AND CELL PHYSIOLOGY, 48, S100, S100, 2007
English, Summary international conference

DESTRUCTION OF MATERNAL CENTRIOLES AND REDUCTION OF CENTRIN MOLECULES IN BROWN ALGAL FERTILIZATION
C. Nagasato; A. Kato; T. Motomura, PHYCOLOGIA, 44, 4, 74, 74, Jul. 2005
English, Summary international conference

ULTRASTRUCTURAL STUDIES ON FLAGELLAR HETEROGENEITY IN ZOOSPORES OF ECTOCARPUS (PHAEOPHYCEAE)
T. Motomura; C. Nagasato; D. G. Mueller, PHYCOLOGIA, 44, 4, 71, 72, Jul. 2005
English, Summary international conference

マコンブ雄性配偶体におけるアルギン酸合成候補遺伝子変異体の表現型解析
長里 千香子; 申 元; 與那嶺 里菜; Cécile Hervé; Yacine Badis; 本村泰三
日本藻類学会第48回大会（神戸）, 24 Mar. 2024, Oral presentation

Phenotyping a knockout mutant of alginate synthesis candidate gene in male gametophytes of Saccharina japonica
Chikako Nagasato; Yuan Shen; Rina Yonamine; Cécile Hervé; Yacine Badis; Taizo Motomura
韓国藻類学会第37回大会（麗水）, 03 Nov. 2023, Invited oral presentation
[Invited]

Plasmodesmata formation in the development of brown algae
Chikako Nagasato
International Research Network Frontiers in Plant Biology, 24 Oct. 2023, Invited oral presentation
[Invited]

褐藻クロガシラの細胞質分裂の進行に伴う細胞骨格の配向変化
青木日向子; Katsaros, C.; 本村泰三; 里千香子
日本植物学会第87回大会（北海道）, 07 Sep. 2023, Oral presentation

環境省モニタリングサイト1000沿岸域調査における藻場のモニタリング 2023年の成果
寺田竜太; 阿部拓三; 神谷充伸; 川井浩史; 倉島彰; 長里千香子; 坂西芳彦; 島袋寛盛; 田中次郎; 上井進也; 青木美鈴
日本藻類学会第48回大会（神戸）, 24 Mar. 2023, Poster presentation

多様性生物学特論Ⅰ, 2024年, 修士課程, 環境科学

ﾌｨｰﾙﾄﾞ科学特別実習Ⅰ, 2024年, 修士課程, 環境科学院

ﾌｨｰﾙﾄﾞ科学特別実習Ⅱ, 2024年, 修士課程, 環境科学院

水圏科学特論Ⅰ, 2024年, 修士課程, 環境科学院

大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目

大学院共通授業科目（一般科目）：自然科学・応用科学, 2024年, 修士課程, 大学院共通科目

生物圏科学実習Ⅰ, 2024年, 修士課程, 環境科学院

生物圏科学実習Ⅱ, 2024年, 修士課程, 環境科学院

ﾌｨーﾙﾄﾞ科学基礎論, 2024年, 修士課程, 環境科学院

環境と人間, 2024年, 学士課程, 全学教育

生物学特別実習Ⅰ, 2024年, 学士課程, 理学部

一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), 2024年, 学士課程, 全学教育

一般教育演習(ﾌﾚｯｼｭﾏﾝｾﾐﾅｰ), 2024年, 学士課程, 全学教育

海藻学実習, 2024年, 学士課程, 理学部

国際交流Ⅱ, 2024年, 学士課程, 国際本部

英語演習, 2024年, 学士課程, 全学教育

褐藻における鉄摂取機構の分子基盤解明
科学研究費助成事業
27 Jun. 2025 - 31 Mar. 2028
長里 千香子; 市原 健介; 米山 明男
日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 25K22376

珪藻のウイルス弱毒化因子は，珪藻個体群の維持システムとして機能するのか？
科学研究費助成事業 基盤研究(B)
01 Apr. 2020 - 31 Mar. 2024
木村 圭; 長里 千香子; 和田 啓
「海の牧草」と称され、海洋資源生物として重要な『珪藻』は、常に強毒ウイルスによる死滅の危機に曝されている。ところが我々研究チームは、珪藻に感染する強毒ウイルスの働きを抑える『弱毒化因子』を発見した。この弱毒化因子は、珪藻 vs 強毒ウイルスの関係性に関与して、珪藻細胞内での強毒ウイルス複製を抑制すると考えられる。さらに、強毒ウイルス蔓延を抑え、珪藻個体群が生残する生態システムの一つとして機能している可能性も考えられる。本研究では、地球上で巨大生産力を誇る珪藻が、強毒ウイルス感染による死滅から回避する戦略の一端として、この弱毒化因子が関与しているのかを生理生態学的に理解することが目的である。
令和３年度は、弱毒化因子の関与によって、珪藻 vs 強毒ウイルスの関係に生じる変化（課題１：形質・発現遺伝子の変化、課題２：構造・形態の変化）を室内実験で解明することに主に取り組んだ。強毒ウイルス株に混在する弱毒化因子を探索するため、DNAウイルス株に存在する弱毒化因子DNA配列を高感度nested PCRにて検出した。その結果、274株のDNAウイルス株中29株から未知DNA因子を検出した。これらの株について、弱毒化因子が存在するウイルス株の違いによって、弱毒化因子DNA配列がどのように異なるのかを解析した。その解析の結果、弱毒化因子は珪藻DNAウイルスと関連を持って存在しており、機能的に保存されるORF領域と、強毒ウイルスに依存するDNA領域の２つを持っていることが示唆された。また、今後研究で使用する弱毒化因子を特異的に認識する抗血清を作成した。
なお、令和３年度では、成果に基づいて国内学会発表（日本藻類学会１件）を実施した。
日本学術振興会, 基盤研究(B), 佐賀大学, 20H03327

珪藻の細胞壁の進化を新奇パルマ藻から探る
科学研究費補助金(基盤研究(C))
2017 - 2019
吉川伸哉
日本学術振興会, Competitive research funding

褐藻類の細胞質分裂におけるプレート状アクチン構造の分子制御機構
科学研究費補助金(基盤研究(C))
2017 - 2019
長里千香子
日本学術会議振興会, Principal investigator, Competitive research funding

褐藻類の原形質連絡調節機構の解明
科学研究費補助金(基盤研究(C))
2014 - 2016
長里千香子
日本学術振興会, Principal investigator, Competitive research funding

ゲノム情報と形態形質進化から探るコンブ目植物による「海の森」の成立
科学研究費補助金(基盤研究(B))
2013 - 2015
川井浩史
日本学術振興会, Competitive research funding

Analysis of membrane fusion process and related proteins on cytokinesis of brown algae
Grants-in-Aid for Scientific Research(若手研究(B))
2009 - 2010
Chikako NAGASATO
In this study, a three dimensional analysis was performed by electron tomography in zygotes of Silvetia babingtonii, for understanding the transitional membrane configuration during cytokinesis. The analysis revealed that a complicated architecture with fringes (TA; tubule-like appendage) were formed by fusion of Golgi derived vesicles to flat cisternae (FCs). Each FC was connected by TAs, thus forming the membranous network (MN). At advanced cytokinesis, the MN grew into broad membranous sac (MS). To turn the 3D image to arbitrary angle indicated a stratification of membrane fusion process from the MN to the MSc. Moreover, proteins extracted from zygotes of Fucus distichus on cytokinesis and cytokinesis blocked zygotes treated with latrunculin B were separated by two-dimensional gel electrophoresis (2-DE). From a total of about 600 spots reproducibly separated on gels, 2-DE from cytokinesis blocked zygotes showed 31 under-expressed and 2 over-expressed proteins in comparison with control.
Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 21770065

ヌクレオモルフの自律性から探る葉緑体二次共生藻類の成立過程
科学研究費補助金(挑戦的萌芽研究)
2009 - 2010
本村 泰三; 石田 健一郎; 長里 千香子
葉緑体二次共生植物(藻類)であるクリプト藻とクロララクニオン藻では、葉緑体となった真核藻類の核の名残りであるヌクレオモルフが観察できる。昨年度は、海産クリプト藻Pyrenomonas helgolandiiについて葉緑体・ヌクレオモルフ・核のDNA合成時期・分裂時期を特定した。その結果は、ヌクレオモルフは1回だけのDNA合成をホストの核分裂直前の2-4時間の間に行うという極めて真核的なものであった。本年度はクリプト藻とは系統が異なるクロララクニオン藻において同様に調査する目的で、Partenskyella glossopodiaの核分裂について電子顕微鏡観察を行った。本種の直径は1.5-3μmと極めて小さく、核とピレノイドを持たない葉緑体が1個ずつという単純な構造であるために連続切片による観察が容易である。その結果、まず葉緑体が分裂し、次にヌクレオモルフが分裂し、細胞にホスト核が分裂することが明らかになった。また、今回の観察と今までの報告からクロララクニオン藻内での核分裂の多様性も示された。次にBrdUの取り込み実験を行ったが、クリプト藻Pyrenomonas helgolandiiと異なり本種ではBrdUの取り込みが確認できなかったためヌクレオモルフにおける正確なDNA合成時期の特定はできなかった。しかし、ホスト核とヌクレオモルフの分裂時期を考えるとクリプト藻の場合と同様に真核的なDNA合成制御を行っているものと推察できた。
日本学術振興会, 挑戦的萌芽研究, 北海道大学, Coinvestigator not use grants, Competitive research funding, 21657018

Studies on recognition system of male and female gametes and cytoplasmic inheritance of organelles during fertilization and zygote development of algae
Grants-in-Aid for Scientific Research(基盤研究(B))
2008 - 2010
Taizo MOTOMURA; Shigeyuki KAWANO; ShinーIchi MIYAMURA; Atsushi KATO; Chikako NAGASATO
Cytoplasmic inheritance of chloroplasts and mitochondria during fertilization of brown algae were studied by electron microscopy and molecular biological techniques using Scytosiphon lomentaria (isogamy), Unidaria pinnatifica and Cystoseira hakodatensis (oogamy). Chloroplasts were derived from both parents in S. lomentaria, while mitochondrial DNA derived from male gametes became selectively disappeared from four-celled sporophytes. In the case of oogamous U. pinnatifida, sperm chloroplasts and mitochondria were digested by lysosome soon after fertilization. In C. hakodatensis, differences of the organellar DNA methylation degrees could be clearly detected between eggs and sperm.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(B), 北海道大学, Coinvestigator not use grants, Competitive research funding, 20370025

Study on decision of cytokinetic plane during an asymmetrica lcell division
Grants-in-Aid for Scientific Research(若手研究(B))
2007 - 2008
Chikako NAGASATO
不等分裂を行う褐藻類の受精卵の最初の細胞質分裂がどのように進行していくか,アクチンはどのような働きをもっているのかについて微細構造レベルで明らかにするために,急速凍結置換法という固定法を用いて透過型電子顕微鏡で詳細に観察を行った。その結果,アクチンは細胞質分裂面に供給される平板小嚢と呼ばれる構造の形成に関与していることが明らかになった一方,細胞質分裂面の決定には直接関与していないことが示唆された。
Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 19770049

雄性配偶子由来セントリオールの鞭毛基底小体から中心体への機能転換に関する研究
科学研究費補助金(若手研究(B))
2005 - 2006
長里 千香子
本年度は、昨年度に引き続き、同形配偶子接合を行なう褐藻カヤモノリの配偶子、接合子を用いて、鞭毛基底小体から中心体へと機能転換する際の中心体構成既知タンパク質の局在変化(ex.セントリン、γチューブリン)について、抗体を用いた蛍光顕微鏡、及び、免疫電子顕微鏡法での観察を行なった。セントリンに関しては、鞭毛基底小体と中心体として機能する際の各々で、セントリオールへの局在箇所に変化が生じている可能性が十分に示唆された。しかしながら、γチューブリンに関しては、蛍光顕微鏡、および、電子顕微鏡での局在観察に関して、市販の抗γチューブリン抗体(SIGMA社、ポリクローナル抗体)では、ウェスタンブロットでの解析、および間接蛍光顕微鏡においては陽性反応を示すものの、電子顕微鏡用の試料上では、非特異的な反応が著しかったこともあり、局在変化を微細構造レベルでとらえることは困難であった。
そのような理由もあり、褐藻カヤモノリのγチューブリンに由来する抗体を作製するため、遺伝子のクローニングを試みることとした。また、同時に、セントリオールを構築するトリプレット微小管に存在し、その構造維持に関係していることが知られている新規チューブリンと呼ばれるε(イプシロン)チューブリン遺伝子のクローニングも試みた。γチューブリンに関しては、生物間で保存性の高いアミノ酸配列部位をもとにプライマーを設計し、εチューブリンに関しては、ゲノムプロジェクトの一貫として進められている褐藻シオミドロのEST解析の情報を利用することとしてRT-PCRを行なった。εチューブリンに関しては、700bpの断片配列を得ることができ、現在、全長配列のクローニングを進めている。γチューブリンに関しては、その局在性の解析からも、細胞周期特異性が非常に強いと予想され、発現に偏りがあるため、継続して遺伝子の単離を行なっている。
日本学術振興会, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 17770050

Molecular and cell biological study on the heterogeneity of flagella in heterokont algae
Grants-in-Aid for Scientific Research(基盤研究(C))
2005 - 2006
Taizo MOTOMURA; 長里 千香子; 加藤 敦之
Heterokont algae usually have a long flagellum attached with mastigonemes and a short one with the basal swelling part, and the structure and the function of these flagella are quite different. In this study, we studied the heterogeneity of two flagella in heterokont algae, especially focusing on the process of their elongation and differentiation using the chrysophycean alga Ochromonas danica and the brown alga Ectocarpus siliculosus. Flagellar duplication in Ochromonas was observed in detail by the time-lapse video microscopy. Moreover, mitosis was observed by electron and immunofluorescence microscopy. Mitosis of Ochromonas is the open spindle type, and the rhizoplast, which is the striated structure from the flagellar basal bodies, is located at both poles. From studies using various antibodies, we found that the rhizoplast of Ochromonas was composed of gannma-tubulin, not centrin. This result shows that the rhizoplast, which can be seen in motile cells in various eukaryotic algal groups, is not homologous, especially on its constituted proteins. In zoosporogenesis in the plurilocular zoidangia of Ectocarpus siliculosus, we examined the process of the flagellar elongation and differentiation using cryofixation under electron microscopy. Both flagella began to elongate simultaneously, while we could detect on which of the flagella is long or short by the difference of the diameter and the associated flagellar rootlets. Interestingly, addition of small vesicles to the flagellar membrane from the plasma membrane was frequently observed. Attachment of mastigonemes to the long flagellum could not be observed, although we were able to clarify the development of the basal swelling part of the short flagellum at where was composed of different materials.
Ministry of Education, Culture, Sports, Science and Technology, 基盤研究(C), 北海道大学, Coinvestigator not use grants, Competitive research funding, 17570047