基本情報

所属

• 水産科学研究院　海洋応用生命科学部門　育種生物学分野

職名

• 助教

学位

• 博士（水産科学）（北海道大学）

科研費研究者番号

• 00760597

ORCID ID

•  https://orcid.org/0000-0002-2925-7913

J-Global ID

• 201301094250782816

研究キーワード

• 海藻育種   植物ホルモン   アミノシクロプロパンカルボン酸   生殖   ストレス応答   海藻類   生活環制御   アマノリ類   紅藻類   

研究分野

• ライフサイエンス / 水圏生命科学 / 海洋植物学

担当教育組織

•  学士課程　水産学部
•  修士課程　水産科学院
•  博士課程　水産科学院

職歴

• 2015年10月 - 現在 北海道大学 大学院水産科学院 助教
• 2015年04月 - 2015年09月 熊本大学 沿岸域環境科学教育研究センター 日本学術振興会特別研究員-PD
• 2013年08月 - 2015年03月 北海道大学 大学院水産科学研究院 特任助教
• 2013年06月 - 2013年07月 北海道大学 大学院水産科学研究院 学術研究員
• 2012年06月 - 2013年05月 フランス国立科学センター ロスコフ生物学研究所 研究員 （上原記念生命科学財団海外留学助成ポストドクトラルフェローシップ）
• 2012年04月 - 2012年05月 北海道大学 大学院水産科学研究院 研究員

学歴

• 2008年04月 - 2012年03月   北海道大学 大学院水産科学院 博士後期課程

所属学協会

• マリンバイオテクノロジー学会   日本水産学会   

研究活動情報

論文

• Development of Chromatin Immunoprecipitation for the Analysis of Histone Modifications in Red Macroalga Neopyropia yezoensis (Rhodophyta).

  Shinnosuke Ueda, Hiroyuki Mizuta, Toshiki Uji

  Molecular biotechnology 2022年09月13日 

  Epigenetic regulation by histone modification can activate or repress transcription through changes in chromatin dynamics and regulates development and the response to environmental signals in both animals and plants. Chromatin immunoprecipitation (ChIP) is an indispensable tool to identify histones with specific post-translational modifications. The lack of a ChIP technique for macroalgae has hindered understanding of the role of histone modification in the expression of genes in this organism. In this study, a ChIP method with several modifications, based on existing protocols for plant cells, has been developed for the red macroalga, Neopyropia yezoensis, that consists of a heterogeneous alternation of macroscopic leaf-like gametophytes and microscopic filamentous sporophytes. ChIP method coupled with qPCR enables the identification of a histone mark in generation-specific genes from N. yezoensis. The results indicate that acetylation of histone H3 at lysine 9 in the 5' flanking and coding regions from generation-specific genes was maintained at relatively high levels, even in generation-repressed gene expression. The use of this ChIP method will contribute significantly to identify the epigenetic regulatory mechanisms through histone modifications that control a variety of biological processes in red macroalgae.
• 1-Aminocyclopropane-1-carboxylic acid and its analogs alleviate heat stress damage in the marine red alga Neopyropia yezoensis (Rhodophyta)

  Toshiki Uji, Hiroyuki Mizuta

  JOURNAL OF APPLIED PHYCOLOGY 34 3 1527 - 1536 2022年06月 

  Heat stress disrupts algal growth, development, and physiological processes, such as photosynthesis, and eventually decreases seaweed productivity. Previous studies of crop plants have revealed that exogenous application of phytohormones prior or parallel to stress can alleviate the negative effects of abiotic stressors, including heat stress. However, there is limited information on phytohormone-induced tolerance to abiotic stressors in seaweed. In the present study, the application of the major plant hormones abscisic acid and salicylic acid failed to mitigate the negative effects of heat stress on the marine red alga Neopyropia yezoensis, whereas 1-aminocyclopropane-1-carboxylic acid (ACC), the direct precursor of the plant hormone ethylene, regulates thermotolerance. In addition, the ACC analogs 1-aminocyclobutane-1-carboxylic acid and alpha-aminoisobutyric acid enhanced tolerance to heat stress. ACC increased the expression of genes involved in antioxidant defense systems to protect photosynthesis and respiration. These results suggest ACC acts as a phytohormone to mitigate the impact on heat stress independent of ethylene in N. yezoensis.
• Phospholipase D activation is required for 1-aminocyclopropane 1-carboxylic acid signaling during sexual reproduction in the marine red alga Neopyropia yezoensis (Rhodophyta).

  Toshiki Uji, Takuya Kandori, Shiho Konishi, Hiroyuki Mizuta

  BMC plant biology 22 1 181 - 181 2022年04月08日 

  BACKGROUND: 1-aminocyclopropane 1-carboxylic acid (ACC) is the immediate precursor of the plant hormone ethylene. However, recent studies have suggested that ACC also acts as a signaling molecule to regulate development and growth independently from ethylene biosynthesis. In red algae, ACC stimulates the switch from a vegetative to a sexual reproductive phase. However, despite evidence that ACC signaling in plants and algae is widespread, the mechanistic basis of the ACC signaling pathway remains unknown. RESULTS: We demonstrate that exogenous ACC increased the activity of phospholipase D (PLD) and induced the accumulation of PLD transcripts in the marine red alga Neopyropia yezoensis. The product of PLD, the lipid second messenger phosphatidic acid (PA), also increased in response to ACC. Furthermore, the pharmacological inhibition of PLD by 1-butanol blocked ACC-induced spermatangia and carpospore production, but the inactive isomer t-butanol did not. In addition, 1-butanol prevented ACC-induced growth inhibition and inhibited transcript accumulation of genes upregulated by ACC, including extracellular matrix (ECM)-related genes, and alleviated the transcriptional decrease of genes downregulated by ACC, including photosynthesis-related genes. CONCLUSIONS: These results indicate that PLD is a positive regulator of sexual cell differentiation and a negative regulator of growth. This study demonstrates that PLD and its product, PA, are components of ACC signaling during sexual reproduction in N. yezoensis.
• Transcriptome Profiling in the Marine Red Alga Neopyropia yezoensis Under Light/Dark Cycle.

  Sayaka Kominami, Hiroyuki Mizuta, Toshiki Uji

  Marine biotechnology (New York, N.Y.) 24 2 393 - 407 2022年04月 

  Many organisms are subjected to a daily cycle of light and darkness, which significantly influences metabolic and physiological processes. In the present study, Neopyropia yezoensis, one of the major cultivated seaweeds used in "nori," was harvested in the morning and evening during light/dark treatments to investigate daily changes in gene expression using RNA-sequencing. A high abundance of transcripts in the morning includes the genes associated with carbon-nitrogen assimilations, polyunsaturated fatty acid, and starch synthesis. In contrast, the upregulation of a subset of the genes associated with the pentose phosphate pathway, cell cycle, and DNA replication at evening is necessary for the tight control of light-sensitive processes, such as DNA replication. Additionally, a high abundance of transcripts at dusk encoding asparaginase and glutamate dehydrogenase imply that regulation of asparagine catabolism and tricarboxylic acid cycle possibly contributes to supply nitrogen and carbon, respectively, for growth during the dark. In addition, genes encoding cryptochrome/photolyase family and histone modification proteins were identified as potential key players for regulating diurnal rhythmic genes.
• The role of plant hormones on the reproductive success of red and brown algae.

  Toshiki Uji, Hiroyuki Mizuta

  Frontiers in plant science 13 1019334 - 1019334 2022年 

  Seaweeds or macroalgae are important primary producers that serve as a habitat for functioning ecosystems. A sustainable production of macroalgae has been maintained by a diverse range of life cycles. Reproduction is the most dynamic change to occur during its life cycle, and it is a key developmental event to ensure the species' survival. There is gradually accumulating evidence that plant hormones, such as abscisic acid and auxin, have a role on the sporogenesis of brown alga (Saccharina japonica). Recent studies reported that 1-aminocylopropane-1-carboxylic acid, an ethylene precursor, regulates sexual reproduction in red alga (Neopyropia yezoensis) independently from ethylene. In addition, these macroalgae have an enhanced tolerance against abiotic and biotic stresses during reproduction to protect their gametes and spores. Herein, we reviewed the current understanding on the regulatory mechanisms of red and brown algae on their transition from vegetative to reproductive phase.
• Extracellular silicate uptake and deposition induced by oxidative burst in Saccharina japonica sporophytes (Phaeophyceae)

  Hiroyuki Mizuta, Toshiki Uji, Hajime Yasui

  ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS 58 2021年10月 [査読有り]
   

  The process of biogenic silicon (Si) deposition in sporophytes of kelp (Saccharina japonica) was investigated by culturing sporophyte disks in the medium with and without hydrogen peroxide (H2O2). Culture with H2O2 remarkably promoted silicate-Si uptake by the disks. Silicate-Si uptake was completely inhibited by the treatment with potassium bromide (KBr), a competitive inhibitor of iodoperoxidase (IPO), even in the medium with H2O2. In addition, disk culture with phenol red in the medium with H2O2 resulted in the formation of bromophenol blue, indicating the presence of extracellular IPO. However, KBr treatment inhibited the formation of bromophenol blue in the medium with H2O2. These results showed that silicate-Si uptake is activated by extracellular IPO in the presence of radical oxygen species (ROS), such as H2O2. Interestingly, 1 mM salicylic acid also promoted silicate-Si uptake, even in the medium without H2O2. Furthermore, the allocation of silicate-Si to the soluble and cell wall-bound phlorotannin fractions using rhodamine 123 (R123), a tracer of biogenic Si, was estimated. Tracer fluorescence was detected in not only the soluble but also the cell wall-bound phlorotannin fraction. R123 fluorescence was histologically detected in the apoplasts of the epidermal and outer cortical layers of the disk, overlapping the histochemical distribution of IPO activity. These results suggested that silicate-Si uptake is activated by an oxidative burst induced by various stresses, and Si deposition is catalyzed by extracellular IPO in the presence of both ROS and phlorotannin in the extracellular matrix of sporophytes. Based on these findings, the hypothetical mechanisms of the extracellular silicate-Si uptake for defense responses in kelp were discussed.
• Treatment with heat shock protein 90 (Hsp90) inhibitors induces asexual life cycle in the marine red alga Neopyropia yezoensis (Rhodophyta)

  Toshiki Uji, Hiroyuki Mizuta

  AQUACULTURE RESEARCH 52 12 6814 - 6817 2021年08月 [査読有り]
  
• Characterization of ACE Inhibitory Peptides Prepared from Pyropia pseudolinearis Protein.

  Yuya Kumagai, Keigo Toji, Satoshi Katsukura, Rie Morikawa, Toshiki Uji, Hajime Yasui, Takeshi Shimizu, Hideki Kishimura

  Marine drugs 19 4 2021年04月01日 

  More than 7000 red algae species have been classified. Although most of them are underused, they are a protein-rich marine resource. The hydrolysates of red algal proteins are good candidates for the inhibition of the angiotensin-I-converting enzyme (ACE). The ACE is one of the key factors for cardiovascular disease, and the inhibition of ACE activity is related to the prevention of high blood pressure. To better understand the relationship between the hydrolysates of red algal proteins and the inhibition of ACE activity, we attempted to identify novel ACE inhibitory peptides from Pyropia pseudolinearis. We prepared water soluble proteins (WSP) containing phycoerythrin, phycocyanin, allophycocyanin, and ribulose 1,5-bisphosphate carboxylase/oxygenase. In vitro analysis showed that the thermolysin hydrolysate of the WSP had high ACE inhibitory activity compared to that of WSP. We then identified 42 peptides in the hydrolysate by high-performance liquid chromatography and mass spectrometry. Among 42 peptides, 23 peptides were found in chloroplast proteins. We then synthesized the uncharacterized peptides ARY, YLR, and LRM and measured the ACE inhibitory activity. LRM showed a low IC50 value (0.15 μmol) compared to ARY and YLR (1.3 and 5.8 μmol). In silico analysis revealed that the LRM sequence was conserved in cpcA from Bangiales and Florideophyceae, indicating that the novel ACE inhibitory peptide LRM was highly conserved in red algae.
• Sexual Reproduction via a 1-Aminocyclopropane-1-Carboxylic Acid-Dependent Pathway Through Redox Modulation in the Marine Red Alga Pyropia yezoensis (Rhodophyta).

  Toshiki Uji, Harune Endo, Hiroyuki Mizuta

  Frontiers in plant science 11 60 - 60 2020年 [査読有り][通常論文]
   

  The transition from the vegetative to sexually reproductive phase is the most dynamic change to occur during a plant's life cycle. In the present study, we showed that the ethylene precursor 1-aminocylopropane-1-carboxylic acid (ACC) induces sexual reproduction in the marine red alga Pyropia yezoensis independently from ethylene. Exogenous application of ACC, which contains a three membered carbocyclic ring, promoted the formation of spermatia and carporspores in gametophytes, whereas ethephon, an ethylene-releasing compound, did not stimulate sexual reproduction. In addition, an ACC analog, 1-aminocyclobutane-1-carboxylic acid (ACBC), which contains a four membered carbocyclic ring, promoted sexual reproduction and enhanced tolerance to oxidative stress in the same manner as ACC, but 1-aminocyclopentane-1-carboxylic acid (cycloleucine; which contains a cyclopentane ring) did not. The application of ACC increased the generation of reactive oxygen species (ROS) and induced the expression of PyRboh gene encoding NADPH oxidase. ACC also stimulated the synthesis of ascorbate (AsA) by inducing transcripts of PyGalLDH, which encodes galactono-1,4-lactone dehydrogenase, the catalyst for the final enzymatic step of the AsA biosynthetic pathway. Conversely, ACC caused a decrease in the synthesis of glutathione (GSH) by repressing transcripts of PyGCL, which encodes glutamate cysteine ligase, the catalyst for the rate-limiting step in the formation of GSH. These results suggest a possible role played by ACC as a signaling molecule independent from ethylene in the regulation of sexual reproduction through alterations to the redox state in P. yezoensis.
• Transcriptomic analysis under ethylene precursor treatment uncovers the regulation of gene expression linked to sexual reproduction in the dioecious red alga Pyropia pseudolinearis

  Ryo Yanagisawa, Naoki Sekine, Hiroyuki Mizuta, Toshiki Uji

  JOURNAL OF APPLIED PHYCOLOGY 31 5 3317 - 3329 2019年10月 [査読有り][通常論文]
   

  The marine red algal genus Pyropia, class Bangiophyceae, includes dioecious and monoecious species; however, the molecular mechanisms underlying control of their sexual reproduction are still poorly understood. In the present study, we demonstrated that application of the ethylene precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), promoted the formation of spermatangia and parthenosporangia in male and female gametophytes, respectively, of the dioecious species Pyropia pseudolinearis. In addition, we determined expression profiles of ACC-responsive genes in the gametophytes during sexual reproduction using RNA-Seq and quantitative real-time PCR (qRT-PCR). Genes involved in the regulation of cell division and cell wall organization, such as high-mobility group (PpHMG) and glycosyltransferase family (PpGT14), were found to be upregulated in male and female gametophytes treated with ACC. In addition, the relatively rapid ACC-response of the vesicular-trafficking-related genes, flotillin (PpFLOT), charged multivesicular body protein 5 (PpCHMP5), and peptidase family S8 (PpS8) was shown to occur during male and female sexual reproduction. Expression levels of these six genes in the monoecious species P. yezoensis, which are homologs to ACC-responsive genes in P. pseudolinearis, also increased in gametophytes treated with ACC. These findings could provide new insights into the ACC-regulation of the sexual life cycle in Pyropia species.
• Complete sequence of mitochondrial DNA of Gloiopeltis furcata (Postels and Ruprecht) J. Agardh

  Watanabe Kei, Kishimoto Takahiro, Kumagai Yuya, Shimizu Takeshi, Uji Toshiki, Yasui Hajime, Kishimura Hideki

  MITOCHONDRIAL DNA PART B-RESOURCES 4 2 2543 - 2544 2019年07月03日 [査読有り][通常論文]
  
• Characterization and expression profiles of small heat shock proteins in the marine red alga Pyropia yezoensis.

  Toshiki Uji, Yohei Gondaira, Satoru Fukuda, Hiroyuki Mizuta, Naotsune Saga

  Cell stress & chaperones 24 1 223 - 233 2019年01月 [査読有り][通常論文]
   

  Small heat shock proteins (sHSPs) are found in all three domains of life (Bacteria, Archaea, and Eukarya) and play a critical role in protecting organisms from a range of environmental stresses. However, little is known about their physiological functions in red algae. Therefore, we characterized the sHSPs (PysHSPs) in the red macroalga Pyropia yezoensis, which inhabits the upper intertidal zone where it experiences fluctuating stressful environmental conditions on a daily and seasonal basis, and examined their expression profiles at different developmental stages and under varying environmental conditions. We identified five PysHSPs (PysHSP18.8, 19.1, 19.2, 19.5, and 25.8). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed that expression of the genes PysHSP18.8, PysHSP19.5, and PysHSP25.8 was repressed at all the developmental stages under normal conditions, whereas PysHSP19.1 and PysHSP19.2 were overexpressed in mature gametophytes and sporophytes. Exposure of the gametophytes to high temperature, oxidative stress, or copper significantly increased the mRNA transcript levels of all the five genes, while exogenous application of the ethylene precursor 1-aminocylopropane-1-carboxylic acid (ACC) significantly increased the expression levels of PysHSP19.2, PysHSP19.5, and PysHSP25.8. These findings will help to further our understanding of the role of PysHSP genes and provide clues about how Pyropia species can adapt to the stressful conditions encountered in the upper intertidal zone during their life cycle.
• Control of elicitor-induced oxidative burst by abscisic acid associated with growth of Saccharina japonica (Phaeophyta, Laminariales) sporophytes

  Kazuki Shimizu, Toshiki Uji, Hajime Yasui, Hiroyuki Mizuta

  Journal of Applied Phycology 30 2 1371 - 1379 2018年04月01日 [査読有り][通常論文]
   

  In this study, the oligoguluronate elicitor-induced oxidative burst (OB) was monitored continuously in young and mature Saccharina japonica sporophytes based on luminol chemiluminescence using a photon counter. The iodoperoxidase (IPO) activity, abscisic acid (ABA), and polyphenol contents were also compared in the different growth stages. The elicitor-induced OB occurred within 1 min and reached its maximum in 15–20 min after treatment in all growth stages. The active elicitor-induced OB was stronger in the young sporophytes than the older sporophytes. The IPO activity in the different growth stages also exhibited a similar pattern to the elicitor-induced OB. These results suggest that the elicitor-induced OB and the subsequent high haloperoxidase activity comprise a major defence mechanism in young sporophytes. By contrast, ABA accumulated with the growth of the sporophytes. Interestingly, ABA treatment suppressed the elicitor-induced OB during growth and enhanced the elicitor-independent IPO activity even in the young sporophytes. In addition, the polyphenol content was higher in the older sporophytes than the younger sporophytes. These observations show that dramatic changes occur in the characteristic defences against biotic stresses as the sporophyte grows, as well as suggesting that ABA is closely linked with these changes. Moreover, the IPO activity recovered slightly in the sorus, which is the reproductive tissue, thereby suggesting that a higher ABA content increases the defence activity and the success of reproduction.
• 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 2017年12月01日 [査読有り][通常論文]
   

  Brown algae are one of the most developmentally complex groups within the eukaryotes. As in many land plants and animals, their main body axis is established early in development, when the initial cell gives rise to two daughter cells that have apical and basal identities, equivalent to shoot and root identities in land plants, respectively. We show here that mutations in the Ectocarpus DISTAG (DIS) gene lead to loss of basal structures during both the gametophyte and the sporophyte generations. Several abnormalities were observed in the germinating initial cell in dis mutants, including increased cell size, disorganization of the Golgi apparatus, disruption of the microtubule network, and aberrant positioning of the nucleus. DIS encodes a TBCCd1 protein, which has a role in internal cell organization in animals, Chlamydomonas reinhardtii, and trypanosomes. Our study highlights the key role of subcellular events within the germinating initial cell in the determination of apical/basal cell identities in a brown alga and emphasizes the remarkable functional conservation of TBCCd1 in regulating internal cell organization across extremely distant eukaryotic groups.
• Ethylene regulation of sexual reproduction in the marine red alga Pyropia yezoensis (Rhodophyta)

  Toshiki Uji, Ryuya Matsuda, Katsuaki Takechi, Hiroyoshi Takano, Hiroyuki Mizuta, Susumu Takio

  JOURNAL OF APPLIED PHYCOLOGY 28 6 3501 - 3509 2016年12月 [査読有り][通常論文]
   

  Plant growth regulators (PGRs) play a pivotal role in vascular plants, regulating growth, development, and stress responses; however, the role of PGRs in algae remains largely unexplored. Here, the role of ethylene, a simple plant growth regulator, was demonstrated in sexual reproduction of the marine red alga Pyropia yezoensis. Application of the ethylene precursor 1-aminocylopropane-1-carboxylic acid (ACC) promoted the formation of spermatia and zygotospores in the gametophytes as well as ethylene production, whereas the growth rate was repressed in comparison to gametophytes not treated with ACC. In addition, gametophytes treated with ACC and mature gametophytes showed enhanced tolerance to oxidative stress. Gene expression profiles revealed upregulation of genes involved in cell division and stress response in gametophytes treated with ACC and in mature gametophytes. These results indicate that ethylene plays an important role in the regulation of gamete formation and protection against stress-induced damage during the sexual reproductive stage. Considered together, these findings demonstrate that ethylene is involved in regulating the switching from a vegetative to a sexual reproductive phase in P. yezoensis.
• Factors influencing the induction of adventitious bud and callus in the brown alga Sargassum horneri (Turner) C. Agardh

  Toshiki Uji, Daisuke Nanaumi, Chikara Kawagoe, Naotsune Saga, Kazuo Miyashita

  JOURNAL OF APPLIED PHYCOLOGY 28 4 2435 - 2443 2016年08月 [査読有り][通常論文]
   

  A high frequency of callus induction and propagation from leaf explants of the brown alga Sargassum horneri was achieved within 2 months of culture when grown in medium supplemented with 5 mu M uniconazole, which is a triazole- type inhibitor of cytochrome P450 enzymes. Adventitious buds were efficiently formed from the pigmented callus after transfer to medium without uniconazole, indicating that treatment with uniconazole was more beneficial for regeneration of the alga. Favorable culture conditions for induction of adventitious buds and calli included temperatures of 15 to 25 degrees C and light levels of 20 to 200 mu mol photons m(-2) s(-1). Blue light promoted the production of adventitious buds and calli. The frequency of formation of adventitious buds and calli in explants from thalli with one leaf was more than 90 %, while it was 10 % only when explants were sourced from thalli with 9 to 11 leaves. These findings will be useful for clonal propagation and storage of seed materials for mariculture of Sargassum species.
• Stable Nuclear Transformation System for the Coccolithophorid Alga Pleurochrysis carterae

  Hirotoshi Endo, Megumi Yoshida, Toshiki Uji, Naotsune Saga, Koji Inoue, Hiromichi Nagasawa

  SCIENTIFIC REPORTS 6 2016年03月 [査読有り][通常論文]
   

  Of the three dominant marine microalgal groups, dinoflagellates and diatoms can undergo genetic transformation; however, no transformation method has been established for haptophytes to date. Here, we report the first stable genetic transformation of a coccolithophore, Pleurochrysis carterae, by means of polyethylene glycol (PEG)-mediated transfer of a bacterial hygromycin B-resistance gene. Together with the novel transient green fluorescent protein (GFP) expression system, this approach should facilitate further molecular-based research in this phylum.
• Characterization of an Eukaryotic PL-7 Alginate Lyase in the Marine Red Alga Pyropia yezoensis.

  Akira Inoue, Chieco Mashino, Toshiki Uji, Naotsune Saga, Koji Mikami, Takao Ojima

  Current biotechnology 4 3 240 - 248 2015年08月 [査読有り][通常論文]
   

  BACKGROUND: Alginate lyases belonging to polysaccharide lyase family-7 (PL-7) are the most well studied on their structures and functions among whole alginate lyases. However, all characterized PL-7 alginate lyases are from prokaryotic bacteria cells. Here we report the first identification of eukaryotic PL-7 alginate lyase from marine red alga Pyropia yezoensis. METHODS: The cDNA encoding an alginate lyase PyAly was cloned and was used for the construction of recombinant PyAly (rPyAly) expression system in Escherichia coli. Purified rPyAly was assayed to identify its enzymatic properties. Its expression pattern in P. yessoensis was also investigated. RESULTS: PyAly is likely a secreted protein consisting of an N-terminal signal peptide of 25 residues and a catalytic domain of 216 residues. The amino-acid sequence of the catalytic domain showed 19-29% identities to those of bacterial characterized alginate lyases classified into family PL-7. Recombinant PyAly protein, rPyAly, which was produced with E. coli BL21(DE3) by cold-inducible expression system, drastically decreased the viscosity of alginate solution in the early stage of reaction. The most preferable substrate for rPyAly was the poly(M) of alginate with an optimal temperature and pH at 35oC and 8.0, respectively. After reaction, unsaturated tri- and tetra-saccharides were produced from poly(M) as major end products. These enzymatic properties indicated that PyAly is an endolytic alginate lyase belonging to PL-7. Moreover, we found that the PyAly gene is split into 4 exons with 3 introns. PyAly was also specifically expressed in the gametophytic haplopid stage. CONCLUSION: This study demonstrates that PyAly in marine red alga P. yezoensis is a novel PL-7 alginate lyase with an endolytic manner. PyAly is a gametophyte-specifically expressed protein and its structural gene is composed of four exons and three introns. Thus, PyAly is the first enzymatically characterized eukaryotic PL-7 alginate lyase.
• 有用海藻における育種研究の現状と将来展望.

  宇治 利樹

  水産育種, 44:pp.41-48 2015年 [査読無し]
  
• DEVELOPMENT OF FORWARD GENETIC AND GENOMIC APPROACHES TO IDENTIFY KEY REGULATORY GENES IN THE BROWN ALGAE

  J. Mark Cock, Alok Arun, Delphine Scornet, Akira F. Peters, Olivier Godfroy, Alexandre Cormier, Nicolas Macaisne, Toshiki Uji, Sophia Ahmed, Susana M. Coelho

  EUROPEAN JOURNAL OF PHYCOLOGY 50 94 - 94 2015年 [査読有り][通常論文]
  
• Development of a nuclear transformation system with a codon-optimized selection marker and reporter genes in Pyropia yezoensis (Rhodophyta)

  Ryo Hirata, Toshiki Uji, Satoru Fukuda, Hiroyuki Mizuta, Asao Fujiyama, Satoshi Tabata, Naotsune Saga

  JOURNAL OF APPLIED PHYCOLOGY 26 4 1863 - 1868 2014年08月 [査読有り][通常論文]
   

  Genetic transformation systems using reporter genes in whole plants have a wide variety of applications for molecular biological study including the visualization of expression patterns of particular genes and intracellular biological phenomena as well as the identification of novel genes. In this study, we assessed co-expression of each three codon-optimized reporter genes and a selectable marker in the nuclear transformation system of whole Pyropia yezoensis, a red marine alga. With the use of an endogenous promoter, both the codon-optimized hygromycin resistance gene and -glucuronidase gene (PyGUS) were co-expressed in P. yezoensis cells. A high level of GUS activity was observed in 60 % of the individuals in hygromycin-resistant lines. A histochemical GUS assay revealed that the PyGUS reporter gene was stably introduced and expressed throughout the algae's life cycle. In addition, two live cell reporters, humanized cyan fluorescent protein from Anemonia majano and luciferase from Gaussia princeps, were successfully expressed in whole P. yezoensis. The development of this transformation system involving three types of reporter genes provides opportunities for monitoring temporal changes in gene expression and for genetic screening in red marine algae.
• A codon-optimized bacterial antibiotic gene used as selection marker for stable nuclear transformation in the marine red alga Pyropia yezoensis.

  Toshiki Uji, Ryo Hirata, Satoru Fukuda, Hiroyuki Mizuta, Naotsune Saga

  Marine biotechnology (New York, N.Y.) 16 3 251 - 5 2014年06月 [査読有り][通常論文]
   

  Marine macroalgae play an important role in marine coastal ecosystems and are widely used as sea vegetation foodstuffs and for industrial purposes. Therefore, there have been increased demands for useful species and varieties of these macroalgae. However, genetic transformation in macroalgae has not yet been established. We have developed a dominant selection marker for stable nuclear transformation in the red macroalga Pyropia yezoensis. We engineered the coding region of the aminoglycoside phosphotransferase gene aph7″ from Streptomyces hygroscopicus to adapt codon usage of the nuclear genes of P. yezoensis. We designated this codon-optimized aph7″ gene as PyAph7. After bombarding P. yezoensis cells with plasmids containing PyAph7 under the control of their endogenous promoter, 1.9 thalli (or individuals) of hygromycin-resistant strains were isolated from a 10-mm square piece of the bombarded thallus. These transformants were stably maintained throughout the asexual life cycle. Stable expression of PyAph7was verified using Southern blot analysis and genomic PCR and RT-PCR analyses. PyAph7 proved to be a new versatile tool for stable nuclear transformation in P. yezoensis.
• Changes in membrane fluidity and phospholipase D activity are required for heat activation of PyMBF1 in Pyropia yezoensis (Rhodophyta)

  Toshiki Uji, Rei Sato, Hiroyuki Mizuta, Naotsune Saga

  JOURNAL OF APPLIED PHYCOLOGY 25 6 1887 - 1893 2013年12月 [査読有り][通常論文]
   

  Multiprotein bridging factor 1 (MBF1) is a highly conserved transcriptional co-activator involved in the regulation of diverse processes, such as environmental stress responses. We recently identified a novel MBF1 gene, PyMBF1, from the marine red alga Pyropia yezoensis. In this study, quantitative real-time PCR analysis revealed that PyMBF1 transcripts were upregulated in P. yezoensis cells during exposure to oxidative and heat stresses. We also examined heat signaling in P. yezoensis cells by monitoring the accumulation of PyMBF1 transcripts. Heat activation of PyMBF1 was inhibited by the membrane rigidifier dimethylsulfoxide, whereas it was induced without heat stress by the membrane fluidizer benzyl alcohol (BA). Induction of PyMBF1 transcripts by heat and BA was inhibited by 1-butanol, an inhibitor of phospholipase D (PLD). The results suggest that the heat activation of PyMBF1 requires membrane fluidization and activation of PLD. These findings provide an initial step toward understanding heat signaling in marine red algae.
• Characterization of the Sporophyte-Preferential Gene Promoter from the Red Alga Porphyra yezoensis Using Transient Gene Expression

  Toshiki Uji, Hiroyuki Mizuta, Naotsune Saga

  MARINE BIOTECHNOLOGY 15 2 188 - 196 2013年04月 [査読有り][通常論文]
   

  The life cycle of plants entails an alternation of generations, the diploid sporophyte and haploid gametophyte stages. There is little information about the characteristics of gene expression during each phase of marine macroalgae. Promoter analysis is a useful method for understanding transcriptional regulation; however, there is no report of promoter analyses in marine macroalgae. In this study, with the aim of elucidating the differences in the transcriptional regulatory mechanisms between the gametophyte and sporophyte stages in the marine red alga Porphyra yezoensis, we isolated the promoter from the sporophyte preferentially expressed gene PyKPA1, which encodes a sodium pump, and analyzed its promoter using a transient gene expression system with a synthetic beta-glucuronidase (PyGUS) reporter. The deletion of -1432 to -768 relative to the transcription start site resulted in decreased GUS activity in sporophytes. In contrast, deletion from -767 to -527 increased GUS activity in gametophytes. Gain-of-function analyses showed that the -1432 to -760 region enhanced the GUS activity of a heterologous promoter in sporophytes, whereas the -767 to -510 region repressed it in gametophytes. Further mutation and gain-of-function analyses of the -767 to -510 region revealed that a 20-bp GC-rich sequence (-633 to -614) is responsible for the gametophyte-specific repressed expression. These results showed that the sporophyte-specific positive regulatory region and gametophyte-specific negative regulatory sequence play a crucial role in the preferential expression of PyKPA1 in P. yezoensis sporophytes.
• Molecular characterization and expression analysis of sodium pump genes in the marine red alga Porphyra yezoensis

  Toshiki Uji, Ryo Hirata, Koji Mikami, Hiroyuki Mizuta, Naotsune Saga

  MOLECULAR BIOLOGY REPORTS 39 8 7973 - 7980 2012年08月 [査読有り][通常論文]
   

  Sodium pumps (EC 3.6.3.9, Na+-ATPase), which mediate excretion of Na+ from the cell, play a crucial role in Na+ homeostasis in eukaryotic cells. The objective of this study is to understand the Na+ efflux system in a marine red alga. We identified a novel sodium pump gene, PyKPA2, from the marine red alga Porphyra yezoensis. The amino acid sequence of PyKPA2 shares 65 % identity with PyKPA1, a previously identified P. yezoensis sodium pump. Similar to PyKPA1, PyKPA2 contains conserved sequences for functions such as phosphorylation, ATP binding, and cation binding. Phylogenetic analysis revealed that the two genes cluster with sodium pumps from algae. Reverse-transcription polymerase chain reaction (RT-PCR) analysis showed that PyKPA1 is expressed preferentially in sporophytes, whereas PyKPA2 is expressed specifically in gametophytes. RT-PCR and quantitative real-time PCR analysis revealed that PyKPA1 and PyKPA2 transcripts were upregulated and downregulated, respectively, in gametophytes during exposure to alkali stress. In addition, transcription of both genes in gametophytes was also induced by cold stress. These results suggest that PyKPA1 and PyKPA2 play an important role in alkali and cold stress tolerance.
• Current status of "nori" cultivation and future on the application of genomic information

  Koji Mikami, Toshiki Uji, Ryo Hirata, Megumu Takahashi, Naotsune Saga

  NIPPON SUISAN GAKKAISHI 78 2 271 - 271 2012年03月 [査読有り][通常論文]
  
• ノリ育種の現状とゲノム情報利用の将来展望

  三上浩司, 平田遼, 宇治利樹, 髙橋潤, 嵯峨直恆

  水産育種, 41: pp. 161-168 2012年
• A Dibasic Amino Acid Pair Conserved in the Activation Loop Directs Plasma Membrane Localization and Is Necessary for Activity of Plant Type I/II Phosphatidylinositol Phosphate Kinase

  Koji Mikami, Laura Saavedra, Yuji Hiwatashi, Toshiki Uji, Mitsuyasu Hasebe, Marianne Sommarin

  PLANT PHYSIOLOGY 153 3 1004 - 1015 2010年07月 [査読有り][通常論文]
   

  Phosphatidylinositol phosphate kinase (PIPK) is an enzyme involved in the regulation of cellular levels of phosphoinositides involved in various physiological processes, such as cytoskeletal organization, ion channel activation, and vesicle trafficking. In animals, research has focused on the modes of activation and function of PIPKs, providing an understanding of the importance of plasma membrane localization. However, it still remains unclear how this issue is regulated in plant PIPKs. Here, we demonstrate that the carboxyl-terminal catalytic domain, which contains the activation loop, is sufficient for plasma membrane localization of PpPIPK1, a type I/II B PIPK from the moss Physcomitrella patens. The importance of the carboxyl-terminal catalytic domain for plasma membrane localization was confirmed with Arabidopsis (Arabidopsis thaliana) AtPIP5K1. Our findings, in which substitution of a conserved dibasic amino acid pair in the activation loop of PpPIPK1 completely prevented plasma membrane targeting and abolished enzymatic activity, demonstrate its critical role in these processes. Placing our results in the context of studies of eukaryotic PIPKs led us to conclude that the function of the dibasic amino acid pair in the activation loop in type I/II PIPKs is plant specific.
• Visualization of Nuclear Localization of Transcription Factors with Cyan and Green Fluorescent Proteins in the Red Alga Porphyra yezoensis

  Toshiki Uji, Megumu Takahashi, Naotsune Saga, Koji Mikami

  MARINE BIOTECHNOLOGY 12 2 150 - 159 2010年04月 [査読有り][通常論文]
   

  Transcription factors play a central role in expression of genomic information in all organisms. The objective of our study is to analyze the function of transcription factors in red algae. One way to analyze transcription factors in eukaryotic cells is to study their nuclear localization, as reported for land plants and green algae using fluorescent proteins. There is, however, no report documenting subcellular localization of transcription factors from red algae. In the present study, using the marine red alga Porphyra yezoensis, we confirmed for the first time successful expression of humanized fluorescent proteins (ZsGFP and ZsYFP) from a reef coral Zoanthus sp. and land plant-adapted sGFP(S65T) in gametophytic cells comparable to expression of AmCFP. Following molecular cloning and characterization of transcription factors DP-E2F-like 1 (PyDEL1), transcription elongation factor 1 (PyElf1) and multiprotein bridging factor 1 (PyMBF1), we then demonstrated that ZsGFP and AmCFP can be used to visualize nuclear localization of PyElf1 and PyMBF1. This is the first report to perform visualization of subcellular localization of transcription factors as genome-encoded proteins in red algae.
• Isolation and regeneration of transiently transformed protoplasts from gametophytic blades of the marine red alga Porphyra yezoensis

  Megumu Takahashi, Toshiki Uji, Naotsune Saga, Koji Mikami

  Electronic Journal of Biotechnology 13 2 1 - 4 2010年 [査読有り][通常論文]
   

  Despite the recent progress of transient gene expression systems in a red alga Porphyra yezoensis by particle bombardment, a stable transformation system has yet to establish in any marine red macrophytes. One of the reasons of the difficulty in genetic transformation in red algae is the lack of systems to select and isolate transformed cells from gametophytic blades. Thus, toward the establishment of the stable transformation system in P. yezoensis, we have developed a procedure by which transiently transformed gametophytic cells were prepared from particle bombarded-gametophytic blade as regeneratable protoplasts. Using mixture of marine bacterial enzymes, yield of protoplasts was high as reported elsewhere however, these protoplasts did not develop. In contrast, protoplasts prepared from gametophytes treated with allantoin were normally developed, in which the overexpression of a β-glucuronidase reporter gene had no effect on the regeneration of protoplasts. Therefore, the use of allantoin in protoplast preparation sheds a new light on the realization of an efficient isolation and selection of study transformed cells from gametophytic blades. © 2010 by Pontificia Universidad Católica de Valparaíso - Chile.
• Visualization of Phosphoinositides via the Development of the Transient Expression System of a Cyan Fluorescent Protein in the Red Alga Porphyra yezoensis

  Koji Mikami, Toshiki Uji, Lin Li, Megumu Takahashi, Hajime Yasui, Naotsune Saga

  MARINE BIOTECHNOLOGY 11 5 563 - 569 2009年10月 [査読有り][通常論文]
   

  Phosphoinositides (PIs) play important roles in signal transduction pathways and the regulation of cytoskeleton and membrane functions in eukaryotes. Subcellular localization of individual PI derivative is successfully visualized in yeast, animal, and green plant cells using PI derivative-specific pleckstrin homology (PH) domains fused with a variety of fluorescent proteins; however, expression of fluorescent proteins has not yet been reported in any red algal cells. In the present study, we developed the system to visualize these PIs using human PH domains fused with a humanized cyan fluorescent protein (AmCFP) in the red alga Porphyra yezoensis. Plasma membrane localization of AmCFP fused with the PH domain from phospholipase C delta 1 and Akt1, but not Bruton's tyrosine kinase, was observed in cell wall-free monospores, demonstrating the presence of phosphatidylinositol-4,5-bisphosphate and phosphatidylinositol-3,4-bisphosphate in P. yezoensis cells. This is the first report of the successful expression of fluorescent protein and the monitoring of PI derivatives in red algal cells. Our system, based on transient expression of AmCFP, could be applicable for the analysis of subcellular localization of other proteins in P. yezoensis and other red algal cells.
• Structural features and gene-expression profiles of actin homologs in Porphyra yezoensis (Rhodophyta)

  Yukihiro Kitade, Michiko Nakamura, Toshiki Uji, Satoru Fukuda, Hirotoshi Endo, Naotsune Saga

  GENE 423 1 79 - 84 2008年10月 [査読有り][通常論文]
   

  The marine red alga Porphyra yezoensis contains an actin gene family consisting of at least four isoforms (PyACT1, 2, 3 and 4). The amino acid identity between isoforms exceeds 83%, and each contains a putative nuclear export signal (NES). We scanned the sequences for amino acids in regions homologous to the intermonomeric interface of actin filaments. Few residues expected to engage in cross-linking were conserved between the four isoforms. The results of the sequence analyses suggest that PyACT2 probably functions in the nucleus as a monomer (G-actin) or in other unconventional forms. In addition, the distribution and position of the introns were different from those in florideophycean actin genes. The expression level of PyACT3 in matured gametophytes was significantly higher than in those in a vegetative state, although the mRNA was detected at similar levels in both apical and basal parts of thalli. The expression levels of PyACT2 and 4, on the other hand, did not change significantly between the matured and vegetative gametophytes. The PyACT3 may serve as a molecular marker for monitoring thallus maturation in this species. (C) 2008 Elsevier B.V. All rights reserved.
• Factors influencing efficiency of transient gene expression in the red macrophyte Porphyra yezoensis

  Satoru Fukuda, Koji Mikami, Toshiki Uji, Eun-Jeong Park, Toshiharu Ohba, Kiyozo Asada, Yukihiro Kitade, Hirotoshi Endo, Ikunoshin Kato, Naotsune Saga

  PLANT SCIENCE 174 3 329 - 339 2008年03月 [査読有り][通常論文]
   

  The marine red alga Porphyra yezoensis has been proposed as a model plant for physiological and genetic studies in seaweeds because of its biological and economical importance. However, the progress of molecular biological studies using gene transfection and genetic transformation systems has been hindered by difficulties in the expression of foreign genes in P. yezoensis cells. To overcome this situation, we developed a transient gene expression system to monitor gene expression in P. yezoensis cells. An artificial beta-glucuronidase (GUS) coding region was synthesized to adapt it to the codon usage of P. yezoensis (PyGUS) and then evaluated for efficiency as a reporter of transient gene expression by particle bombardment. We also demonstrated the importance of using the promoter of the glyceraldehyde-3-phosphate dehydrogenase (GAPDH) gene from P. yezoensis for efficient expression of PyGUS, because the cauliflower mosaic virus (CaMV) 35S promoter, which has been successfully used for monitoring gene expression in nuclei and chloroplasts of higher plants, was less active in P. yezoensis cells. Therefore, the lack of knowledge about differences in the regulatory machinery of gene expression between P. yezoensis and terrestrial plants seems to be why experimental systems for monitoring gene expression were previously not developed in P. yezoensis. Establishment of the transient gene expression system in P yezoensis could facilitate biotechnological developments in this organism. (c) 2007 Elsevier Ireland Ltd. All rights reserved.

書籍

• Emergence of Ectocarpus as a model system to study the evolution of complex multicellularity in the brown algae. In: "Evolutionary transitions to multicellular life"

  Cock J.M, Godfroy O, Strittmatter M, Scornet D, Uji T, Farnham G, Peters A.F. Coelho S 
  Springer, pp 153-162, (2015)
• Transient gene expression systems in Porphyra yezoensis: establishment, application and limitation.Porphyra yezoensis: Frontiers in Physiological and Molecular Biological Research.

  Mikami K, Uji T 
  New York: Nova Science Publishers, pp 93-117. (2012)
• Transient transformation of red algal cells: Breakthrough toward genetic transformation of marine crop Porphyra species.

  Mikami K, Hirata R, Takahashi M, Uji T, Saga N 
  InTech-Open Access Publisher, pp 241-258. (2011)

作品等

• 有用紅藻類における生殖機構に関する研究

  LASBOS Moodle  宇治 利樹  2020年04月 - 現在
• 海藻における有用遺伝子の探索手法の開発

  2022年05月

その他活動・業績

• 海苔の原料であるスサビノリにおけるエチレン前駆物質の役割について

  宇治 利樹 アグリバイオ 2022年10月
• 紅藻類の有性生殖に関わる制御機構-アマノリ類における1-アミノシクロプロパンカルボン酸の役割を中心に-

  宇治利樹 藻類 69 (1) 2021年 [査読有り][招待有り]
  
• 海洋深層水を活用した海藻スプラウトの陸上養殖と利用適性に関する研究

  木下康宣, 木村和世, 川越力, 高野智宏, 熊谷祐也, 岸村栄毅, 宇治利樹, 水田浩之 北海道立工業技術センター研究成果発表会要旨集(Web) 2021 2021年
• 東北地方沖太平洋の流れ藻から採集された甲殻類および魚類

  樋口淳也, 河合俊郎, 宇治利樹, 今井圭理 北海道大学水産科学研究彙報(Web) 71 (1) 2021年
• スサビノリの野生株と外来遺伝子導入株の交雑

  泉ひかり, 宇治利樹, 水田浩之, 嵯峨直恆, 福田覚 日本水産学会大会講演要旨集 2020 2020年
• スサビノリ葉状体におけるブロモペルオキシダーゼ遺伝子の発現機構解析

  松田竜也, 宇治利樹, 武智克彰, 高野博嘉, 瀧尾進 マリンバイオテクノロジー学会大会講演要旨集 17th 114 2015年05月30日 [査読無し][通常論文]
  
• 紅藻スサビノリにおける改変ハイグロマイシン耐性遺伝子を選択マーカーとした形質転換技術の開発

  宇治利樹, 平田遼, 福田覚, 水田浩之, 嵯峨直恆 日本水産学会大会講演要旨集 2014 2014年
• Molecular characterization and expression analysis of two Na+/H+ antiporter genes in the marine red alga Porphyra yezoensis

  Toshiki Uji, Ryota Monma, Hiroyuki Mizuta, Naotsune Saga FISHERIES SCIENCE 78 (5) 985 -991 2012年09月 [査読無し][通常論文]
   

  Na+/H+ antiporters are known to play a crucial role in pH and Na+ homeostasis. In the present study, we characterized the molecular structures and expression patterns of two Na+/H+ antiporters from the marine red alga Porphyra yezoensis (designated PySOS1 and PyNhaD). The full-length cDNAs of PySOS1 and PyNhaD were 5122 and 1804 bp, and contained open reading frames (ORFs) of 4773 and 1275 bp, respectively. The deduced amino acid sequences showed high similarity to SOS1 and NhaD from the higher plant Arabidopsis thaliana. PySOS1 and PyNhaD contained conserved sequences found in the cation-proton antiporter. Quantitative real-time PCR analysis revealed that both antiporter genes were expressed in both the gametophyte and sporophyte of P. yezoensis. In addition, mRNA expression of PySOS1 and PyNhaD was simultaneously upregulated by light irradiation, suggesting that coordinated activity between the two is important in pH and Na+ homeostasis under light conditions. Moreover, the expression levels of both genes were partially reduced by the photosynthetic inhibitors DCMU and DBMIB, suggesting that upregulation is linked to photosynthesis-related metabolism. These findings provide an initial step towards understanding Na+/H+ antiporters in marine red algae.
• Development of an expression system using the heat shock protein 70 promoter in the red macroalga, Porphyra tenera

  Su Hyun Son, Joon-Woo Ahn, Toshiki Uji, Dong-Woog Choi, Eun-Jeong Park, Mi Sook Hwang, Jang Ryol Liu, Dongsu Choi, Koji Mikami, Won-Joong Jeong JOURNAL OF APPLIED PHYCOLOGY 24 (1) 79 -87 2012年01月 [査読無し][通常論文]
   

  Porphyra is a commercially valuable source of food and drugs and an important model organism for algal research. However, genetic research on Porphyra tenera has been limited by a lack of a heterologous gene expression system. In this study, we isolated native promoter PtHSP70 for the efficient expression of foreign genes in this organism. This promoter lies approximately 1 kb upstream of the heat shock protein 70 coding sequence and was isolated using adapter ligation-mediated genomic polymerase chain reaction. Promoter activity was evaluated using the synthetic GUS gene (PyGUS) with optimized codons for Porphyra yezoensis. Interestingly, the PtHSP70 promoter allowed the efficient expression of PyGUS in P. tenera and P. yezoensis, whereas the PyGAPDH promoter from P. yezoensis was not fully functional in P. tenera. The PtHSP70 promoter may have a more conserved regulatory mechanism than the PyGAPDH promoter between these species, suggesting that PtHSP70 could serve as a universal promoter for Porphyra species. We also established an efficient transient transformation system for P. tenera by evaluating transformation parameters including gold particle quantity, helium and vacuum pressure, developmental stages of leafy gametophytes, and target distance. Under optimal conditions of transient transformation, the frequency of GUS expression was determined by histochemical staining as 30-50 cells per bombardment. In addition, PyGUS expression was detected during the regeneration of monospores in P. tenera, indicating successful genetic transformation. Therefore, the new transient transformation system using the PtHSP70 promoter can be used for foreign gene expression in P. tenera, which may advance the development of P. tenera as a model organism.
• 海産紅藻スサビノリの異型世代交代における胞子体世代優占的な遺伝子転写制御機構の解析

  宇治利樹, 嵯峨直恆, 三上浩司 日本植物生理学会年会要旨集 52nd 206 2011年03月11日 [査読無し][通常論文]
  
• 海産原始紅藻スサビノリPorphyra yezoensisのプロトプラストへの蛍光タンパク質遺伝子導入法の開発

  橋潤, 宇治利樹, 嵯峨直恆, 三上浩司 日本植物生理学会年会要旨集 50th 372 2009年03月16日 [査読無し][通常論文]
  
• 紅藻スサビノリにおける一過的遺伝子発現系の開発

  宇治利樹, 三上浩司, 福田覚, 大場利治, 浅田起代蔵, 北出幸広, 遠藤博寿, 朴恩貞, 加藤郁之進, 嵯峨直恆 日本植物生理学会年会要旨集 49th 2008年
• 紅藻スサビノリ配偶体の成熟をモニターする分子マーカーの探索

  北出幸広, 中村理湖, 宇治利樹, 福田覚, 遠藤博寿, 嵯峨直恆 生化学 2007年

受賞

• 2020年10月 ベストポスター賞 第6回北大・部局横断シンポジウム
  
• 2011年05月 平成22年度マリンバイオテクノロジー学会論文賞
   

  受賞者: 宇治 利樹

共同研究・競争的資金等の研究課題

• 紅藻スサビノリにおけるエチレン前駆物質による炭素・窒素代謝バランスの制御

  日本学術振興会：科学研究費助成事業 基盤研究(C)

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 宇治 利樹
• エチレン前駆物質による紅藻スサビノリの有性生殖の制御機構に関する研究

  日本学術振興会：科学研究費助成事業 若手研究

  研究期間 : 2019年04月 -2022年03月 

  代表者 : 宇治 利樹
• アミノ酸添加による有用海藻類の健全かつ効率的な種苗生産技術の開発

  栗林育英学術財団：令和2年度研究助成（個人研究の部）

  研究期間 : 2020年09月 -2021年09月
• 岩海苔の安定的な増養殖を目指した胞子形成および放出機構の解明

  ノーステック財団：若手研究人材・ネットワーク育成補助金

  研究期間 : 2020年09月 -2021年03月
• 北方系海藻の通年収穫を目的とした陸上栽培技術の開発

  ノーステック財団 令和元年度（2019年度）「研究開発助成事業」 スタートアップ研究補助金：

  研究期間 : 2019年08月 -2020年03月 

  代表者 : 川越 力, 水田浩之, 宇治利樹, 木下康宣, 岸村栄毅, 熊谷祐也
• 海苔の有用品種作出に向けたスサビノリのエチレン応答機構の解明

  日本学術振興会：科学研究費助成事業 若手研究(B)

  研究期間 : 2016年04月 -2019年03月 

  代表者 : 宇治 利樹

   

  本研究では、海苔の原料であるスサビノリの有性生殖や酸化ストレス応答にエチレンではなく、その前駆物質である1-アミノシクロプロパン-1-カルボン酸(ACC)が関与していることを明らかにし、海藻において初めて、ACC依存的なシグナル伝達系の存在の可能性を示した。またその応答にはNADPHオキシダーゼ由来の活性酸素種（ROS）が関与していることも見出した。さらにACC応答性遺伝子として、小胞体輸送や細胞分裂、抗酸化に関連する遺伝子を同定し、これらの遺伝子が本種の有性生殖や抗酸化獲得に関与している可能性が明らかとなった。
• 「次世代型アカモク養殖を目指したビックデータ構築と種苗生産の確立

  COI拠点「食と健康の達人」拠点 」

  研究期間 : 2018年12月 -2019年03月 

  代表者 : 宇治 利樹
• 海苔の有用品種作出に向けた紅藻スサビノリにおける高温応答機構の解明

  日本学術振興会：科学研究費助成事業 特別研究員奨励費

  研究期間 : 2015年04月 -2016年03月 

  代表者 : 宇治 利樹

   

  本研究では当初、エチレン（ACC）と高温耐性の関連に焦点を当てて解析を行ったが、高温耐性以外の効果について以下のことが明らかとなった。スサビノリ由来のACC合成酵素遺伝子PyACSが銅およびH2O2ストレス条件下において発現が誘導されることから、エチレンがこれらのストレスに対して応答するために重要な機能をしている可能性が示唆された。そこで、ACC処理による銅ストレスやH2O2ストレス耐性の効果を調べたところ、未処理の藻体と比較して、ACC処理藻体では大量の果胞子様細胞を形成することにより、これらのストレスに適応することが明らかとなった。また長期間（２週間以上）のACC処理により、光合成色素タンパク質であるフィコエリスリン、フィコシアニンおよびクロロフィルの分解が促進されること、生殖細胞の形成が促進されることが明らかとなった。そのため、エチレンの応答機構を解明することにより、高温耐性等の環境ストレス応答機構に加えて、色落ちや有性成熟の機構の解明につながることが期待される。そしてこれらの知見は海苔の品種改良を進めていく上で重要な知見になることが予想される。
  またエチレンのスサビノリに対する作用機序に関する知見を得るために、エチレンによって制御されている遺伝子群の網羅的な同定を試みた。次世代シーケンサー（イルミナ社Hiseq2000）を用いてRNA-seq解析を行った結果、ストレス耐性に関与する候補遺伝子として、カタラーゼ、分子シャペロン（DnaJ）およびプロテインキナーゼ遺伝子等の発現が、ACC処理藻体サンプルにおいて上昇することが明らかとなった。またエチレン応答性遺伝子として、RWP-RKドメインを持つ遺伝子を見出した。この遺伝子は他の生物において転写調節因子をコードすることから、スサビノリにおいても重要な機能を持つ可能性が考えられた。
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