業績情報

• Defective pollen meiosis in Arabidopsis due to combined arabinan and galactan insufficiency　　　　　　　　　　　　　　　
  Takuma Kikuchi; Kouichi Soga; Toshihisa Kotake; Daisuke Takahashi
  2025年02月
  DOI：https://doi.org/10.1101/2025.02.03.636199
  DOI ID：10.1101/2025.02.03.636199, ORCID：177630155
• Glucomannan engineering highlights roles of galactosyl modification in fine-tuning cellulose-glucomannan interaction in Arabidopsis cell walls
  Yoshihisa Yoshimi; Li Yu; Rosalie Cresswell; Xinyu Guo; Alberto Echevarría-Poza; Jan J. Lyczakowski; Ray Dupree; Toshihisa Kotake; Paul Dupree
  Nature Communications, 巻：16, 号：1, 2025年01月, ［査読有り］
  Abstract
  
  Widely found in most plant lineages, β-mannans are structurally diverse polysaccharides that can bind to cellulose fibrils to form the complex polysaccharide architecture of the cell wall. How changes in polysaccharide structure influence its cell wall solubility or promote appropriate interaction with cellulose fibrils is poorly understood. Glucomannan backbones acquire variable patterns of galactosyl substitutions, depending on plant developmental stage and species. Here, we show that fine-tuning of galactosyl modification on glucomannans is achieved by the differing acceptor recognition of mannan α-galactosyltransferases (MAGTs). Biochemical analysis and ¹³C solid-state nuclear magnetic resonance spectroscopy of Arabidopsis with cell wall glucomannan engineered by MAGTs reveal that the degree of galactosylation strongly affects the interaction with cellulose. The findings indicate that plants tailor galactosyl modification on glucomannans for constructing an appropriate cell wall architecture, paving the way to convert properties of lignocellulosic biomass for better use.
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/s41467-025-56626-y
  DOI ID：10.1038/s41467-025-56626-y, eISSN：2041-1723
• Soluble sugars make a greater contribution than cell wall components to the variability of freezing tolerance in wheat cultivars
  Sushan Chowhan; Takuma Kikuchi; Momoka Ohashi; Tatsuya Kutsuno; Hiroto Handa; Toshihisa Kotake; Daisuke Takahashi
  Plant Biotechnology, 巻：41, 号：4, 開始ページ：401, 終了ページ：415, 2024年12月, ［査読有り］
  Japanese Society for Plant Cell and Molecular Biology, 研究論文（学術雑誌）
  DOI：https://doi.org/10.5511/plantbiotechnology.24.0801a
  DOI ID：10.5511/plantbiotechnology.24.0801a, ISSN：1342-4580, eISSN：1347-6114
• SHORT AND CROOKED AWN, Encoding an Epigenetic Regulator EMF1, Promotes Barley Awn Development.　　　　　　　　　　　　　　　
  Koki Nakamura; Yuichi Kikuchi; Mizuho Shiraga; Toshihisa Kotake; Kiwamu Hyodo; Shin Taketa; Yoko Ikeda
  Plant & cell physiology, 2024年12月, ［査読有り］, ［国内誌］
  The awn is a bristle-like extension from the lemma of grass spikelets. In barley, the predominant cultivars possess long awns that contribute to grain yield and quality through photosynthesis. Barley is a useful cereal crop to investigate the mechanism of awn development as various awn morphological mutants are available. Here, we identified the gene causative of the short and crooked awn (sca) mutant, which exhibits a short and curved awn phenotype. Intercrossing experiments revealed that the sca mutant induced in the Japanese cultivar (cv.) 'Akashinriki' is allelic to independently isolated moderately short-awn mutant breviaristatum-a (ari-a). Map-based cloning and sequencing revealed that SCA encodes the Polycomb group-associated protein EMBRYONIC FLOWER 1 (EMF1). We found that SCA affects awn development through the promotion of cell proliferation, elongation, and cell wall synthesis. RNA sequencing of cv. Bowman (BW) backcross-derived near-isogenic lines of sca and ari-a6 alleles showed that SCA is directly or indirectly involved in promoting the expression of genes related to awn development. Additionally, SCA represses various transcription factors essential for floral organ development and plant architecture, such as MADS-box and KNOX1 genes. Notably, the repression of the C-class MADS-box gene HvMADS58 by SCA in awns is associated with the accumulation of the repressive histone modification H3K27me3. These findings highlight the potential role of SCA-mediated gene regulation, including histone modification, as a novel pathway in barley awn development.
  Oxford University Press (OUP), 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcae150
  DOI ID：10.1093/pcp/pcae150, ISSN：0032-0781, eISSN：1471-9053, PubMed ID：39704093
• Cytosolic UDP‐L‐arabinose synthesis by bifunctional UDP‐glucose 4‐epimerases in Arabidopsis
  Akira Umezawa; Mayuko Matsumoto; Hiroto Handa; Konatsu Nakazawa; Megumi Miyagawa; Georg J. Seifert; Daisuke Takahashi; Shinya Fushinobu; Toshihisa Kotake
  The Plant Journal, 巻：118, 開始ページ：508, 終了ページ：524, 2024年04月, ［査読有り］, ［最終著者, 責任著者］
  SUMMARY
  
  L‐Arabinose (L‐Ara) is a plant‐specific sugar found in cell wall polysaccharides, proteoglycans, glycoproteins, and small glycoconjugates, which play physiologically important roles in cell proliferation and other essential cellular processes. L‐Ara is synthesized as UDP‐L‐arabinose (UDP‐L‐Ara) from UDP‐xylose (UDP‐Xyl) by UDP‐Xyl 4‐epimerases (UXEs), a type of de novo synthesis of L‐Ara unique to plants. In Arabidopsis, the Golgi‐localized UXE AtMUR4 is the main contributor to UDP‐L‐Ara synthesis. However, cytosolic bifunctional UDP‐glucose 4‐epimerases (UGEs) with UXE activity, AtUGE1, and AtUGE3 also catalyze this reaction. For the present study, we first examined the physiological importance of bifunctional UGEs in Arabidopsis. The uge1 and uge3 mutants enhanced the dwarf phenotype of mur4 and further reduced the L‐Ara content in cell walls, suggesting that bifunctional UGEs contribute to UDP‐L‐Ara synthesis. Through the introduction of point mutations exchanging corresponding amino acid residues between AtUGE1 with high UXE activity and AtUGE2 with low UXE activity, two mutations that increase relative UXE activity of AtUGE2 were identified. The crystal structures of AtUGE2 in complex forms with NAD⁺ and NAD⁺/UDP revealed that the UDP‐binding domain of AtUGE2 has a more closed conformation and smaller sugar‐binding site than bacterial and mammalian UGEs, suggesting that plant UGEs have the appropriate size and shape for binding UDP‐Xyl and UDP‐L‐Ara to exhibit UXE activity. The presented results suggest that the capacity for cytosolic synthesis of UDP‐L‐Ara was acquired by the small sugar‐binding site and several mutations of UGEs, enabling diversified utilization of L‐Ara in seed plants.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/tpj.16779
  DOI ID：10.1111/tpj.16779, ISSN：0960-7412, eISSN：1365-313X
• Structural changes in cell wall pectic polymers contribute to freezing tolerance induced by cold acclimation in plants　　　　　　　　　　　　　　　
  Daisuke Takahashi; Kouichi Soga; Takuma Kikuchi; Tatsuya Kutsuno; Pengfei Hao; Kazuma Sasaki; Yui Nishiyama; Satoshi Kidokoro; Arun Sampathkumar; Antony Bacic; Kim L. Johnson; Toshihisa Kotake
  Current Biology, 巻：34, 号：5, 開始ページ：958, 終了ページ：968.e5, 2024年03月, ［査読有り］, ［最終著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.cub.2024.01.045
  DOI ID：10.1016/j.cub.2024.01.045, ISSN：0960-9822
• Hydrogen chloride treatment of rice straw for upcycling into nanofibrous products for sugar pool　　　　　　　　　　　　　　　
  Ken Tokuyasu; Kenji Yamagishi; Toshihisa Kotake; Satoshi Kimura; Masakazu Ike
  Bioresource Technology Reports, 巻：25, 開始ページ：101717, 終了ページ：101717, 2024年02月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.biteb.2023.101717
  DOI ID：10.1016/j.biteb.2023.101717, ISSN：2589-014X
• On the Separate Metabolisms of UDP-Sugars and GDP-Sugars in Plants
  Toshihisa Kotake; Daisuke Takahashi
  Trends in Glycoscience and Glycotechnology, 巻：36, 号：209, 開始ページ：E6, 終了ページ：E11, 2024年01月, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］
  Forum: Carbohydrates Coming of Age, 研究論文（学術雑誌）
  DOI：https://doi.org/10.4052/tigg.2303.1e
  DOI ID：10.4052/tigg.2303.1e, ISSN：0915-7352, eISSN：1883-2113
• Smooth Elongation of Pavement Cells Induced by RIC1 Overexpression Leads to Marginal Protrusions of the Cotyledon in Arabidopsis thaliana
  Kotomi Kikukawa; Hisako Takigawa-Imamura; Kouichi Soga; Toshihisa Kotake; Takumi Higaki
  Plant And Cell Physiology, 巻：64, 号：11, 開始ページ：1356, 終了ページ：1371, 2023年09月, ［査読有り］
  Abstract
  
  The interdigitated pavement cell shape is suggested to be mechanically rational at both the cellular and tissue levels, but the biological significance of the cell shape is not fully understood. In this study, we explored the potential importance of the jigsaw puzzle-like cell shape for cotyledon morphogenesis in Arabidopsis. We used a transgenic line overexpressing a Rho-like GTPase-interacting protein, ROP-INTERACTIVE CRIB MOTIF-CONTAINING PROTEIN 1 (RIC1), which causes simple elongation of pavement cells. Computer-assisted microscopic analyses, including virtual reality observation, revealed that RIC1 overexpression resulted in abnormal cotyledon shapes with marginal protrusions, suggesting that the abnormal organ shape might be explained by changes in the pavement cell shape. Microscopic, biochemical and mechanical observations indicated that the pavement cell deformation might be due to reduction in the cell wall cellulose content with alteration of cortical microtubule organization. To examine our hypothesis that simple elongation of pavement cells leads to an abnormal shape with marginal protrusion of the cotyledon, we developed a mathematical model that examines the impact of planar cell growth geometry on the morphogenesis of the organ that is an assemblage of the cells. Computer simulations supported experimental observations that elongated pavement cells resulted in an irregular cotyledon shape, suggesting that marginal protrusions were due to local growth variation possibly caused by stochastic bias in the direction of cell elongation cannot be explained only by polarity-based cell elongation, but that an organ-level regulatory mechanism is required.
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcad094
  DOI ID：10.1093/pcp/pcad094, ISSN：0032-0781, eISSN：1471-9053
• Integrated genome-wide differentiation and association analyses identify causal genes underlying breeding-selected grain quality traits in japonica rice　　　　　　　　　　　　　　　
  Hideki Yoshida; Satoshi Okada; Fanmiao Wang; Shohei Shiota; Masaki Mori; Mayuko Kawamura; Xue Zhao; Yiqiao Wang; Naho Nishigaki; Asako Kobayashi; Kotaro Miura; Shinya Yoshida; Masaru Ikegami; Akitoshi Ito; Lin-Tzu Huang; Yue-Ie Caroline Hsing; Yoshiyuki Yamagata; Yoichi Morinaka; Masanori Yamasaki; Toshihisa Kotake; Eiji Yamamoto; Jian Sun; Ko Hirano; Makoto Matsuoka
  Molecular Plant, 巻：16, 号：9, 開始ページ：1460, 終了ページ：1477, 2023年09月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.molp.2023.09.002
  DOI ID：10.1016/j.molp.2023.09.002, ISSN：1674-2052
• Autophagy accelerates cell death after desiccation and hydration stress in Physcomitrium　　　　　　　　　　　　　　　
  Kyosuke Mukae; Md. Arif Sakil; Toshihisa Kotake; Yuko Inoue-Aono; Yuji Moriyasu
  Environmental and Experimental Botany, 巻：213, 開始ページ：105412, 終了ページ：105412, 2023年09月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.envexpbot.2023.105412
  DOI ID：10.1016/j.envexpbot.2023.105412, ISSN：0098-8472
• Plant type II arabinogalactan: Structural features and modification to increase functionality　　　　　　　　　　　　　　　
  Kanika Ghosh; Daisuke Takahashi; Toshihisa Kotake
  Carbohydrate Research, 巻：529, 開始ページ：108828, 終了ページ：108828, 2023年07月, ［査読有り］, ［最終著者, 責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2023.108828
  DOI ID：10.1016/j.carres.2023.108828, ISSN：0008-6215
• Rhamnogalacturonan-I as a nematode chemoattractant from Lotus corniculatus L. super-growing root culture
  Morihiro Oota; Syuuto Toyoda; Toshihisa Kotake; Naoki Wada; Masatsugu Hashiguchi; Ryo Akashi; Hayato Ishikawa; Bruno Favery; Allen Yi-Lun Tsai; Shinichiro Sawa
  Frontiers in Plant Science, 巻：13, 開始ページ：1008725, 2023年01月, ［査読有り］
  Introduction
  
  The soil houses a tremendous amount of micro-organisms, many of which are plant parasites and pathogens by feeding off plant roots for sustenance. Such root pathogens and parasites often rely on plant-secreted signaling molecules in the rhizosphere as host guidance cues. Here we describe the isolation and characterization of a chemoattractant of plant-parasitic root-knot nematodes (Meloidogyne incognita, RKN).
  
  Methods
  
  The Super-growing Root (SR) culture, consisting of excised roots from the legume species Lotus corniculatus L., was found to strongly attract infective RKN juveniles and actively secrete chemoattractants into the liquid culture media. The chemo-attractant in the culture media supernatant was purified using hydrophobicity and anion exchange chromatography, and found to be enriched in carbohydrates.
  
  Results
  
  Monosaccharide analyses suggest the chemo-attractant contains a wide array of sugars, but is enriched in arabinose, galactose and galacturonic acid. This purified chemoattractant was shown to contain pectin, specifically anti-rhamnogalacturonan-I and anti-arabinogalactan protein epitopes but not anti-homogalacturonan epitopes. More importantly, the arabinose and galactose sidechain groups were found to be essential for RKN-attracting activities. This chemo-attractant appears to be specific to M. incognita, as it wasn’t effective in attracting other Meloidogyne species nor Caenorhabditis elegans.
  
  Discussion
  
  This is the first report to identify the nematode attractant purified from root exudate of L corniculatus L. Our findings re-enforce pectic carbohydrates as important chemicals mediating micro-organism chemotaxis in the soil, and also highlight the unexpected utilities of the SR culture system in root pathogen research.
  Frontiers Media SA, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3389/fpls.2022.1008725
  DOI ID：10.3389/fpls.2022.1008725, eISSN：1664-462X
• Temporal cell wall changes during cold acclimation and deacclimation and their potential involvement in freezing tolerance and growth.　　　　　　　　　　　　　　　
  Kutsuno T; Sushan Chowhan; Toshihisa Kotake; Daisuke Takahashi
  Physiologia plantarum, 巻：175, 開始ページ：e13837, 2023年01月, ［査読有り］
  Plants adapt to freezing stress through cold acclimation, which is induced by nonfreezing low temperatures and accompanied by growth arrest. A later increase in temperature after cold acclimation leads to rapid loss of freezing tolerance and growth resumption, a process called deacclimation. Appropriate regulation of the trade-off between freezing tolerance and growth is necessary for efficient plant development in a changing environment. The cell wall, which mainly consists of polysaccharide polymers, is involved in both freezing tolerance and growth. Still, it is unclear how the balance between freezing tolerance and growth is affected during cold acclimation and deacclimation by the changes in cell wall structure and what role is played by its monosaccharide composition. Therefore, to elucidate the regulatory mechanisms controlling freezing tolerance and growth during cold acclimation and deacclimation, we investigated cell wall changes in detail by sequential fractionation and monosaccharide composition analysis in the model plant Arabidopsis thaliana, for which a plethora of information and mutant lines are available. We found that arabinogalactan proteins and pectic galactan changed in close coordination with changes in freezing tolerance and growth during cold acclimation and deacclimation. On the other hand, arabinan and xyloglucan did not return to nonacclimation levels after deacclimation but stabilized at cold acclimation levels. This indicates that deacclimation does not completely restore cell wall composition to the nonacclimated state but rather changes it to a specific novel composition that is probably a consequence of the loss of freezing tolerance and provides conditions for growth resumption.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/ppl.13837
  DOI ID：10.1111/ppl.13837, ISSN：0031-9317, eISSN：1399-3054, ORCID：156844425, PubMed ID：36461890, PubMed Central ID：PMC10107845
• Surface-localized glycoproteins act through class C ARFs to fine-tune gametophore initiation in Physcomitrium patens.　　　　　　　　　　　　　　　
  Ooi-kock Teh; Singh P; Ren J; Huang LT; Ariyarathne M; Salamon BP; Wang Y; Toshihisa Kotake; Tomomichi Fujita
  Development (Cambridge, England), 巻：149, 号：24, 開始ページ：dev200370, 2022年12月, ［査読有り］
  ABSTRACT
  
  Arabinogalactan proteins are functionally diverse cell wall structural glycoproteins that have been implicated in cell wall remodeling, although the mechanistic actions remain elusive. Here, we identify and characterize two AGP glycoproteins, SLEEPING BEAUTY (SB) and SB-like (SBL), that negatively regulate the gametophore bud initiation in Physcomitrium patens by dampening cell wall loosening/softening. Disruption of SB and SBL led to accelerated gametophore formation and altered cell wall compositions. The function of SB is glycosylation dependent and genetically connected with the class C auxin response factor (ARF) transcription factors PpARFC1B and PpARFC2. Transcriptomics profiling showed that SB upregulates PpARFC2, which in turn suppresses a range of cell wall-modifying genes that are required for cell wall loosening/softening. We further show that PpARFC2 binds directly to multiple AuxRE motifs on the cis-regulatory sequences of PECTIN METHYLESTERASE to suppress its expression. Hence, our results demonstrate a mechanism by which the SB modulates the strength of intracellular auxin signaling output, which is necessary to fine-tune the timing of gametophore initials formation.
  The Company of Biologists, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1242/dev.200370
  DOI ID：10.1242/dev.200370, ISSN：0950-1991, eISSN：1477-9129, ORCID：156844405, PubMed ID：36520083
• Metabolomic analysis of rice brittle culm mutants reveals each mutant- specific metabolic pattern in each organ
  Atsuko Miyagi; Kazuhisa Mori; Toshiki Ishikawa; Satoshi Ohkubo; Shunsuke Adachi; Masatoshi Yamaguchi; Taiichiro Ookawa; Toshihisa Kotake; Maki Kawai-Yamada
  Metabolomics, 巻：18, 号：12, 開始ページ：95, 2022年11月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11306-022-01958-9
  DOI ID：10.1007/s11306-022-01958-9, eISSN：1573-3890, ORCID：125142203
• In vivo structural modification of type II arabinogalactans with fungal endo-β-1,6-galactanase in Arabidopsis　　　　　　　　　　　　　　　
  Aina Kikuchi; Katsuya Hara; Yoshihisa Yoshimi; Kouichi Soga; Daisuke Takahashi; Toshihisa Kotake
  Frontiers in Plant Science, 巻：13, 開始ページ：1010492, 2022年11月, ［査読有り］, ［最終著者, 責任著者］
  Arabinogalactan-proteins (AGPs) are mysterious extracellular glycoproteins in plants. Although AGPs are highly conserved, their molecular functions remain obscure. The physiological importance of AGPs has been extensively demonstrated with β-Yariv reagent, which specifically binds to AGPs and upon introduction into cells, causes various deleterious effects including growth inhibition and programmed cell death. However, structural features of AGPs that determine their functions have not been identified with β-Yariv reagent. It is known that AGPs are decorated with large type II arabinogalactans (AGs), which are necessary for their functions. Type II AGs consist of a β-1,3-galactan main chain and β-1,6-galactan side chains with auxiliary sugar residues such as L-arabinose and 4-O-methyl-glucuronic acid. While most side chains are short, long side chains such as β-1,6-galactohexaose (β-1,6-Gal6) also exist in type II AGs. To gain insight into the structures important for AGP functions, in vivo structural modification of β-1,6-galactan side chains was performed in Arabidopsis. We generated transgenic Arabidopsis plants expressing a fungal endo-β-1,6-galactanase, Tv6GAL, that degrades long side chains specifically under the control of dexamethasone (Dex). Two of 6 transgenic lines obtained showed more than 40 times activity of endo-β-1,6-galactanase when treated with Dex. Structural analysis indicated that long side chains such as β-1,6-Gal5 and β-1,6-Gal6 were significantly reduced compared to wild-type plants. Tv6GAL induction caused retarded growth of seedlings, which had a reduced amount of cellulose in cell walls. These results suggest that long β-1,6-galactan side chains are necessary for normal cellulose synthesis and/or deposition as their defect affects cell growth in plants.
  Frontiers Media {SA}, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3389/fpls.2022.1010492
  DOI ID：10.3389/fpls.2022.1010492, ISSN：1664-462X, ORCID：123976005
• Amino Acids Supplied through the Autophagy/Endocytosis Pathway Promote Starch Synthesis in Physcomitrella Protonemal Cells.　　　　　　　　　　　　　　　
  Md Arif Sakil; Kyosuke Mukae; Ryo Funada; Toshihisa Kotake; Shigeaki Ueno; Most Mohoshena Aktar; Md Shyduzzaman Roni; Yuko Inoue-Aono; Yuji Moriyasu
  Plants (Basel, Switzerland), 巻：11, 号：16, 2022年08月, ［査読有り］, ［国際誌］
  The physiological implications of autophagy in plant cells have not been fully elucidated. Therefore, we investigated the consequences of autophagy in the moss Physcomitrella by measuring biochemical parameters (fresh and dry weights; starch, amino acid, carbohydrate, and NH3 content) in wild-type (WT) and autophagy-deficient atg5 Physcomitrella cells. We found higher starch levels and a higher net starch synthesis rate in WT cells than in atg5 cells cultured in a glucose-containing culture medium, whereas net starch degradation was similar in the two strains cultured in a glucose-deficient culture medium. Additionally, the treatment of cells with the autophagy inhibitor 3-methyladenine suppressed starch synthesis. Loading bovine serum albumin into atg5 cells through endocytosis, i.e., supplying proteins to vacuoles in the same way as through autophagy, accelerated starch synthesis, whereas loading glutamine through the plasma membrane had no such effect, suggesting that Physcomitrella cells distinguish between different amino acid supply pathways. After net starch synthesis, NH3 levels increased in WT cells, although the change in total amino acid content did not differ between WT and atg5 cells, indicating that autophagy-produced amino acids are oxidized rapidly. We conclude that autophagy promotes starch synthesis in Physcomitrella by supplying the energy obtained by oxidizing autophagy-produced amino acids.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/plants11162157
  DOI ID：10.3390/plants11162157, PubMed ID：36015461, PubMed Central ID：PMC9412964
• Hydroxycinnamic acid‐modified xylan side chains and their cross‐linking products in rice cell walls are reduced in the Xylosyl arabinosyl substitution of xylan 1 mutant
  Carolina Feijao; Kris Morreel; Nadine Anders; Theodora Tryfona; Marta Busse‐Wicher; Toshihisa Kotake; Wout Boerjan; Paul Dupree
  The Plant Journal, 巻：109, 号：5, 開始ページ：1152, 終了ページ：1167, 2022年03月, ［査読有り］
  Wiley, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/tpj.15620
  DOI ID：10.1111/tpj.15620, ISSN：0960-7412, eISSN：1365-313X, ORCID：123976179
• The Mechanics and Biology of Plant Cell Walls: Resilience and Sustainability for Our Future Society　　　　　　　　　　　　　　　
  Misato Ohtani; Toshihisa Kotake; Jenny C Mortimer; Taku Demura
  Plant and Cell Physiology, 巻：62, 号：12, 開始ページ：1787, 終了ページ：1790, 2021年12月, ［招待有り］, ［国内誌］
  Oxford University Press (OUP), 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcab168
  DOI ID：10.1093/pcp/pcab168, ISSN：0032-0781, eISSN：1471-9053, PubMed ID：34958673
• Superoxide Production by the Red Tide-Producing Chattonella marina Complex (Raphidophyceae) Correlates with Toxicity to Aquacultured Fishes
  Tomoyuki Shikata; Koki Yuasa; Saho Kitatsuji; Setsuko Sakamoto; Kazuki Akita; Yuichiro Fujinami; Yoshitaka Nishiyama; Toshihisa Kotake; Ryusuke Tanaka; Yasuhiro Yamasaki
  Antioxidants, 巻：10, 号：10, 開始ページ：1635, 終了ページ：1635, 2021年10月, ［査読有り］
  The marine raphidophyte Chattonella marina complex forms red tides, causing heavy mortalities of aquacultured fishes in temperate coastal waters worldwide. The mechanism for Chattonella fish mortality remains unresolved. Although several toxic chemicals have been proposed as responsible for fish mortality, the cause is still unclear. In this study, we performed toxicity bioassays with red sea bream and yellowtail. We also measured biological parameters potentially related to ichthyotoxicity, such as cell size, superoxide (O2•−) production, and compositions of fatty acids and sugars, in up to eight Chattonella strains to investigate possible correlations with toxicity. There were significant differences in moribundity rates of fish and in all biological parameters among strains. One strain displayed no ichthyotoxicity even at high cell densities. Strains were categorized into three groups based on cell length, but this classification did not significantly correlate with ichthyotoxicity. O2•− production differed by a factor of more than 13 between strains at the late exponential growth phase. O2•− production was significantly correlated with ichthyotoxicity. Differences in fatty acid and sugar contents were not related to ichthyotoxicity. Our study supports the hypothesis that superoxide can directly or indirectly play an important role in the Chattonella-related mortality of aquacultured fishes.
  MDPI AG, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/antiox10101635
  DOI ID：10.3390/antiox10101635, eISSN：2076-3921
• Galactoglucomannan structure of Arabidopsis seed‐coat mucilage in GDP‐mannose synthesis impaired mutants　　　　　　　　　　　　　　　
  Naho Nishigaki; Yoshihisa Yoshimi; Hiroaki Kuki; Tadashi Kunieda; Ikuko Hara‐Nishimura; Yoichi Tsumuraya; Daisuke Takahashi; Paul Dupree; Toshihisa Kotake
  Physiologia Plantarum, 巻：173, 号：3, 開始ページ：1244, 終了ページ：1252, 2021年08月, ［査読有り］, ［最終著者, 責任著者］, ［国際誌］
  Cell-wall polysaccharides are synthesized from nucleotide sugars by glycosyltransferases. However, in what way the level of nucleotide sugars affects the structure of the polysaccharides is not entirely clear. guanosine diphosphate (GDP)-mannose (GDP-Man) is one of the major nucleotide sugars in plants and serves as a substrate in the synthesis of mannan polysaccharides. GDP-Man is synthesized from mannose 1-phosphate and GTP by a GDP-Man pyrophosphorylase, VITAMIN C DEFECTIVE1 (VTC1), which is positively regulated by the interacting protein KONJAC1 (KJC1) in Arabidopsis. Since seed-coat mucilage can serve as a model of the plant cell wall, we examined the influence of vtc1 and kjc1 mutations on the synthesis of mucilage galactoglucomannan. Sugar composition analysis showed that mannose content in adherent mucilage of kjc1 and vtc1 mutants was only 42% and 11% of the wild-type, respectively, indicating a drastic decrease of galactoglucomannan. On the other hand, structural analysis based on specific oligosaccharides released by endo-β-1,4-mannanase indicated that galactoglucomannan had a patterned glucomannan backbone consisting of alternating residues of glucose and mannose and the frequency of α-galactosyl branches was also similar to the wild type structure. These results suggest that the structure of mucilage galactoglucomannan is mainly determined by properties of glycosyltransferases rather than the availability of nucleotide sugars.
  Wiley, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/ppl.13519
  DOI ID：10.1111/ppl.13519, ISSN：0031-9317, eISSN：1399-3054, PubMed ID：34380178
• Root-knot nematode chemotaxis is positively regulated by l-galactose sidechains of mucilage carbohydrate rhamnogalacturonan-I　　　　　　　　　　　　　　　
  Allen Yi-Lun Tsai; Yuka Iwamoto; Yoichi Tsumuraya; Morihiro Oota; Teruko Konishi; Shinsaku Ito; Toshihisa Kotake; Hayato Ishikawa; Shinichiro Sawa
  Science Advances, 巻：7, 号：27, 開始ページ：eabh4182, 終了ページ：eabh4182, 2021年07月, ［査読有り］, ［国際誌］
  Root-knot nematodes (RKNs) are plant parasites and major agricultural pests. RKNs are thought to locate hosts through chemotaxis by sensing host-secreted chemoattractants; however, the structures and properties of these attractants are not well understood. Here, we describe a previously unknown RKN attractant from flaxseed mucilage that enhances infection of Arabidopsis and tomato, which resembles the pectic polysaccharide rhamnogalacturonan-I (RG-I). Fucose and galactose sidechains of the purified attractant were found to be required for attractant activity. Furthermore, the disaccharide α-l-galactosyl-1,3-l-rhamnose, which forms the linkage between the RG-I backbone and galactose sidechains of the purified attractant, was sufficient to attract RKN. These results show that the α-l-galactosyl-1,3-l-rhamnose linkage in the purified attractant from flaxseed mucilage is essential for RKN attraction. The present work also suggests that nematodes can detect environmental chemicals with high specificity, such as the presence of chiral centers and hydroxyl groups.
  American Association for the Advancement of Science (AAAS), 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1126/sciadv.abh4182
  DOI ID：10.1126/sciadv.abh4182, eISSN：2375-2548, PubMed ID：34215589
• Wolfberry genomes and the evolution of Lycium (Solanaceae)
  You-Long Cao; Yan-long Li; Yun-Fang Fan; Zhen Li; Kouki Yoshida; Jie-Yu Wang; Xiao-Kai Ma; Ning Wang; Nobutaka Mitsuda; Toshihisa Kotake; Takeshi Ishimizu; Kun-Chan Tsai; Shan-Ce Niu; Diyang Zhang; Wei-Hong Sun; Qing Luo; Jian-Hua Zhao; Yue Yin; Bo Zhang; Jun-Yi Wang; Ken Qin; Wei An; Jun He; Guo-Li Dai; Ya-Jun Wang; Zhi-Gang Shi; En-Ning Jiao; Peng-Ju Wu; Xuedie Liu; Bin Liu; Xing-Yu Liao; Yu-Ting Jiang; Xia Yu; Yang Hao; Xin-Yu Xu; Shuang-Quan Zou; Ming-He Li; Yu-Yun Hsiao; Yu-Fu Lin; Chieh-Kai Liang; You-Yi Chen; Wan-Lin Wu; Hsiang-Chai Lu; Si-Ren Lan; Zhi-Wen Wang; Xiang Zhao; Wen-Ying Zhong; Chuan-Ming Yeh; Wen-Chieh Tsai; Yves Van de Peer; Zhong-Jian Liu
  Communications Biology, 巻：4, 号：1, 2021年06月, ［査読有り］
  Wolfberry Lycium, an economically important genus of the Solanaceae family, contains approximately 80 species and shows a fragmented distribution pattern among the Northern and Southern Hemispheres. Although several herbaceous species of Solanaceae have been subjected to genome sequencing, thus far, no genome sequences of woody representatives have been available. Here, we sequenced the genomes of 13 perennial woody species of Lycium, with a focus on Lycium barbarum. Integration with other genomes provides clear evidence supporting a whole-genome triplication (WGT) event shared by all hitherto sequenced solanaceous plants, which occurred shortly after the divergence of Solanaceae and Convolvulaceae. We identified new gene families and gene family expansions and contractions that first appeared in Solanaceae. Based on the identification of self-incompatibility related-gene families, we inferred that hybridization hotspots are enriched for genes that might be functioning in gametophytic self-incompatibility pathways in wolfberry. Extremely low expression of LOCULE NUBER (LC) and COLORLESS NON-RIPENING (CNR) orthologous genes during Lycium fruit development and ripening processes suggests functional diversification of these two genes between Lycium and tomato. The existence of additional flowering locus C-like MADS-box genes might correlate with the perennial flowering cycle of Lycium. Differential gene expression involved in the lignin biosynthetic pathway between Lycium and tomato likely illustrates woody and herbaceous differentiation. We also provide evidence that Lycium migrated from Africa into Asia, and subsequently from Asia into North America. Our results provide functional insights into Solanaceae origins, evolution and diversification.
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/s42003-021-02152-8
  DOI ID：10.1038/s42003-021-02152-8, eISSN：2399-3642, ORCID：94891667
• Biochemical and structural characterization of a novel 4‐ O ‐α‐ l ‐rhamnosyl‐β‐ d ‐glucuronidase from Fusarium oxysporum
  Tatsuya Kondo; Miyu Kichijo; Makoto Nakaya; Shigeo Takenaka; Takatoshi Arakawa; Toshihisa Kotake; Shinya Fushinobu; Tatsuji Sakamoto
  The FEBS Journal, 巻：288, 号：16, 開始ページ：4918, 終了ページ：4938, 2021年03月, ［査読有り］
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/febs.15795
  DOI ID：10.1111/febs.15795, ISSN：1742-464X, eISSN：1742-4658
• A Pipeline towards the Biochemical Characterization of the Arabidopsis GT14 Family
  Lingling Xuan; Jie Zhang; Weitai Lu; Pawel Gluza; Berit Ebert; Toshihisa Kotake; Mengzhu Lu; Yuan Zhang; Mads H. Clausen; Kim L. Johnson; Monika S. Doblin; Joshua L. Heazlewood; Antony Bacic; Lili Song; Wei Zeng
  International Journal of Molecular Sciences, 巻：22, 号：3, 開始ページ：1360, 終了ページ：1360, 2021年01月, ［査読有り］
  Glycosyltransferases (GTs) catalyze the synthesis of glycosidic linkages and are essential in the biosynthesis of glycans, glycoconjugates (glycolipids and glycoproteins), and glycosides. Plant genomes generally encode many more GTs than animal genomes due to the synthesis of a cell wall and a wide variety of glycosylated secondary metabolites. The Arabidopsis thaliana genome is predicted to encode over 573 GTs that are currently classified into 42 diverse families. The biochemical functions of most of these GTs are still unknown. In this study, we updated the JBEI Arabidopsis GT clone collection by cloning an additional 105 GT cDNAs, 508 in total (89%), into Gateway-compatible vectors for downstream characterization. We further established a functional analysis pipeline using transient expression in tobacco (Nicotiana benthamiana) followed by enzymatic assays, fractionation of enzymatic products by reversed-phase HPLC (RP-HPLC) and characterization by mass spectrometry (MS). Using the GT14 family as an exemplar, we outline a strategy for identifying effective substrates of GT enzymes. By addition of UDP-GlcA as donor and the synthetic acceptors galactose-nitrobenzodiazole (Gal-NBD), β-1,6-galactotetraose (β-1,6-Gal4) and β-1,3-galactopentose (β-1,3-Gal5) to microsomes expressing individual GT14 enzymes, we verified the β-glucuronosyltransferase (GlcAT) activity of three members of this family (AtGlcAT14A, B, and E). In addition, a new family member (AT4G27480, 248) was shown to possess significantly higher activity than other GT14 enzymes. Our data indicate a likely role in arabinogalactan-protein (AGP) biosynthesis for these GT14 members. Together, the updated Arabidopsis GT clone collection and the biochemical analysis pipeline present an efficient means to identify and characterize novel GT catalytic activities.
  {MDPI} {AG}, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/ijms22031360
  DOI ID：10.3390/ijms22031360, eISSN：1422-0067, ORCID：87761722
• Structural features conserved in subclass of type II arabinogalactan
  Kengo Ito; Kurumi Fukuoka; Naho Nishigaki; Katsuya Hara; Yoshihisa Yoshimi; Hiroaki Kuki; Daisuke Takahashi; Yoichi Tsumuraya; Toshihisa Kotake
  Plant Biotechnology, 巻：37, 号：4, 開始ページ：459, 終了ページ：463, 2020年12月, ［査読有り］, ［最終著者, 責任著者］
  Japanese Society for Plant Cell and Molecular Biology, 研究論文（学術雑誌）
  DOI：https://doi.org/10.5511/plantbiotechnology.20.0721a
  DOI ID：10.5511/plantbiotechnology.20.0721a, ISSN：1342-4580, eISSN：1347-6114
• Unique active-site and subsite features in the arabinogalactan-degrading GH43 exo-β-1,3-galactanase from Phanerochaete chrysosporium　　　　　　　　　　　　　　　
  Kaori Matsuyama; Naomi Kishine; Zui Fujimoto; Naoki Sunagawa; Toshihisa Kotake; Yoichi Tsumuraya; Masahiro Samejima; Kiyohiko Igarashi; Satoshi Kaneko
  Journal of Biological Chemistry, 巻：295, 号：52, 開始ページ：18539, 終了ページ：18552, 2020年12月, ［査読有り］, ［国際誌］
  Arabinogalactan proteins (AGPs) are plant proteoglycans with functions in growth and development. However, these functions are largely unexplored, mainly because of the complexity of the sugar moieties. These carbohydrate sequences are generally analyzed with the aid of glycoside hydrolases. The exo-β-1,3-galactanase is a glycoside hydrolase from the basidiomycete Phanerochaete chrysosporium (Pc1,3Gal43A), which specifically cleaves AGPs. However, its structure is not known in relation to its mechanism bypassing side chains. In this study, we solved the apo and liganded structures of Pc1,3Gal43A, which reveal a glycoside hydrolase family 43 subfamily 24 (GH43_sub24) catalytic domain together with a carbohydrate-binding module family 35 (CBM35) binding domain. GH43_sub24 is known to lack the catalytic base Asp conserved among other GH43 subfamilies. Our structure in combination with kinetic analyses reveals that the tautomerized imidic acid group of Gln263 serves as the catalytic base residue instead. Pc1,3Gal43A has three subsites that continue from the bottom of the catalytic pocket to the solvent. Subsite -1 contains a space that can accommodate the C-6 methylol of Gal, enabling the enzyme to bypass the β-1,6-linked galactan side chains of AGPs. Furthermore, the galactan-binding domain in CBM35 has a different ligand interaction mechanism from other sugar-binding CBM35s, including those that bind galactomannan. Specifically, we noted a Gly → Trp substitution, which affects pyranose stacking, and an Asp → Asn substitution in the binding pocket, which recognizes β-linked rather than α-linked Gal residues. These findings should facilitate further structural analysis of AGPs and may also be helpful in engineering designer enzymes for efficient biomass utilization.
  Elsevier BV, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.ra120.016149
  DOI ID：10.1074/jbc.ra120.016149, ISSN：0021-9258, PubMed ID：33093171
• Calcium Binding by Arabinogalactan Polysaccharides Is Important for Normal Plant Development
  Federico Lopez-Hernandez; Theodora Tryfona; Annalisa Rizza; Xiaolan L. Yu; Matthew O.B. Harris; Alex A.R. Webb; Toshihisa Kotake; Paul Dupree
  The Plant Cell, 巻：32, 号：10, 開始ページ：3346, 終了ページ：3369, 2020年10月, ［査読有り］
  American Society of Plant Biologists ({ASPB}), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1105/tpc.20.00027
  DOI ID：10.1105/tpc.20.00027, ISSN：1040-4651, eISSN：1532-298X, ORCID：81355787
• Crystal structure of GH43 exo-β-1,3-galactanase from the basidiomycetePhanerochaete chrysosporium provides insights into the mechanism of bypassing side chains　　　　　　　　　　　　　　　
  Kaori Matsuyama; Naomi Kishine; Zui Fujimoto; Naoki Sunagawa; Toshihisa Kotake; Yoichi Tsumuraya; Masahiro Samejima; Kiyohiko Igarashi; Satoshi Kaneko
  2020年09月, ［査読有り］
  DOI：https://doi.org/10.1101/2020.09.23.310037
  DOI ID：10.1101/2020.09.23.310037, ORCID：80848695
• Expression of a fungal exo-β-1,3-galactanase in Arabidopsis reveals a role of type II arabinogalactans in the regulation of cell shape　　　　　　　　　　　　　　　
  Yoshihisa Yoshimi; Katsuya Hara; Mami Yoshimura; Nobukazu Tanaka; Takumi Higaki; Yoichi Tsumuraya; Toshihisa Kotake
  Journal of Experimental Botany, 巻：71, 号：18, 開始ページ：5414, 終了ページ：5424, 2020年09月, ［査読有り］, ［最終著者, 責任著者］, ［国際誌］
  Arabinogalactan-proteins (AGPs) are a family of plant extracellular proteoglycans implicated in many physiological events. AGP is decorated with type II arabinogalactans (AGs) consisting of a β-1,3-galactan backbone and β-1,6-galactan side chains, to which other sugars are attached. Based on the fact that a type II AG-specific inhibitor, β-Yariv reagent, perturbs growth and development, it has been proposed that type II AGs participate in the regulation of cell shape and tissue organization. However, the mechanisms by which type II AGs participate have not yet been established. Here, we describe a novel system that causes specific degradation of type II AGs in Arabidopsis, by which a gene encoding a fungal exo-β-1,3-galactanase that specifically hydrolyzes β-1,3-galactan backbones of type II AGs is expressed under the control of a dexamethasone-inducible promoter. Dexamethasone treatment increased the galactanase activity, leading to a decrease in Yariv reagent-reactive AGPs in transgenic Arabidopsis. We detected the typical oligosaccharides released from type II AGs by Il3GAL in the soluble fraction, demonstrating that Il3GAL acted on type II AG in the transgenic plants. Additionally, this resulted in severe tissue disorganization in the hypocotyl and cotyledons, suggesting that the degradation of type II AGs affected the regulation of cell shape.
  Oxford University Press (OUP), 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/jxb/eraa236
  DOI ID：10.1093/jxb/eraa236, ISSN：0022-0957, eISSN：1460-2431, PubMed ID：32470141, PubMed Central ID：PMC7501824
• Microgravity affects the level of matrix polysaccharide 1,3:1,4-beta-glucans in cell walls of rice shoots by increasing the expression level of a gene involved in their breakdown　　　　　　　　　　　　　　　
  Wakabayashi K; Soga K; Hoson T; Kotake T; Yamazaki T; Ishioka N; Shimazu T; Kamada M
  Astrobiology, 巻：20, 開始ページ：820, 終了ページ：829, 2020年, ［査読有り］
  英語
• Properties of arabinogalactan-proteins in European pear (Pyrus communis L.) fruits
  Tsumuraya, Y.; Ozeki, E.; Ooki, Y.; Yoshimi, Y.; Hashizume, K.; Kotake, T.
  Carbohydrate Research, 巻：485, 開始ページ：107816, 終了ページ：107816, 2019年11月, ［査読有り］, ［最終著者, 責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2019.107816
  DOI ID：10.1016/j.carres.2019.107816, ISSN：0008-6215, ORCID：63916521, SCOPUS ID：85072301772
• Degradative enzymes for type II arabinogalactan side chains in Bifidobacterium longum subsp. longum
  Fujita, K.; Sakamoto, A.; Kaneko, S.; Kotake, T.; Tsumuraya, Y.; Kitahara, K.
  Applied Microbiology and Biotechnology, 巻：103, 号：3, 開始ページ：1299, 終了ページ：1310, 2019年02月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00253-018-9566-4
  DOI ID：10.1007/s00253-018-9566-4, ISSN：0175-7598, eISSN：1432-0614, ORCID：63916500, SCOPUS ID：85061872997
• Yariv reactivity of type II arabinogalactan from larch wood　　　　　　　　　　　　　　　
  Sato, K.; Hara, K.; Yoshimi, Y.; Kitazawa, K.; Ito, H.; Tsumuraya, Y.; Kotake, T.
  Carbohydrate Research, 巻：467, 開始ページ：8, 終了ページ：13, 2018年09月, ［査読有り］, ［責任著者］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2018.07.004
  DOI ID：10.1016/j.carres.2018.07.004, ISSN：0008-6215, ORCID：63916540, PubMed ID：30036728, SCOPUS ID：85050163032
• The patterned structure of galactoglucomannan suggests it may bind to cellulose in seed mucilage　　　　　　　　　　　　　　　
  Yu, L.; Lyczakowski, J.J.; Pereira, C.S.; Kotake, T.; Yu, X.; Li, A.; Mogelsvang, S.; Skaf, M.S.; Dupree, P.
  Plant Physiology, 巻：178, 号：3, 2018年09月, ［査読有り］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.18.00709
  DOI ID：10.1104/pp.18.00709, ISSN：0032-0889, ORCID：63916531, PubMed ID：30185440, SCOPUS ID：85055514451
• Correction to: Metabolism of l-arabinose in plants (Journal of Plant Research, (2016), 129, 5, (781-792), 10.1007/s10265-016-0834-z)
  Kotake, T.; Yamanashi, Y.; Imaizumi, C.; Tsumuraya, Y.
  Journal of Plant Research, 巻：131, 号：3, 開始ページ：565, 終了ページ：565, 2018年
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10265-018-1012-2
  DOI ID：10.1007/s10265-018-1012-2, ORCID：63916543, SCOPUS ID：85042225730
• Modification of growth anisotropy and cortical microtubule dynamics in Arabidopsis hypocotyls grown under microgravity conditions in space　　　　　　　　　　　　　　　
  Kouichi Soga; Chiaki Yamazaki; Motoshi Kamada; Naoki Tanigawa; Haruo Kasahara; Sachiko Yano; Kei H. Kojo; Natsumaro Kutsuna; Takehide Kato; Takashi Hashimoto; Toshihisa Kotake; Kazuyuki Wakabayashi; Takayuki Hoson
  Physiologia Plantarum, 巻：162, 号：1, 開始ページ：135, 終了ページ：144, 2018年01月, ［査読有り］
  We carried out a space experiment, denoted as Aniso Tubule, to examine the effects of microgravity on the growth anisotropy and cortical microtubule dynamics in Arabidopsis hypocotyls, using lines in which microtubules are visualized by labeling tubulin or microtubule-associated proteins (MAPs) with green fluorescent protein (GFP). In all lines, GFP-tubulin6 (TUB6)-, basic proline-rich protein1 (BPP1)-GFP- and spira1-like3 (SP1L3)-GFP-expressing using a constitutive promoter, and spiral2 (SPR2)-GFP- and GFP-65 kDa MAP-1 (MAP65-1)-expressing using a native promoter, the length of hypocotyls grown under microgravity conditions in space was longer than that grown at 1 g conditions on the ground. In contrast, the diameter of hypocotyls grown under microgravity conditions was smaller than that of the hypocotyls grown at 1 g. The percentage of cells with transverse microtubules was increased under microgravity conditions, irrespective of the lines. Also, the average angle of the microtubules with respect to the transverse cell axis was decreased in hypocotyls grown under microgravity conditions. When GFP fluorescence was quantified in hypocotyls of GFP-MAP65-1 and SPR2-GFP lines, microgravity increased the levels of MAP65-1, which appears to be involved in the maintenance of transverse microtubule orientation. However, the levels of SPR2 under microgravity conditions were comparable to those at 1 g. These results suggest that the microgravity-induced increase in the levels of MAP65-1 is involved in increase in the transverse microtubules, which may lead to modification of growth anisotropy, thereby developing longer and thinner hypocotyls under microgravity conditions in space.
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/ppl.12640
  DOI ID：10.1111/ppl.12640, ISSN：0031-9317, eISSN：1399-3054, PubMed ID：28862767, Web of Science ID：WOS:000418236000009
• Properties of two fungal endo-β-1,3-galactanases and their synergistic action with an exo-β-1,3-galactanase in degrading arabinogalactan-proteins.　　　　　　　　　　　　　　　
  Yoshimi Y; Yaguchi K; Kaneko S; Tsumuraya Y; Kotake T
  Carbohydrate Research, 巻：453-454, 開始ページ：26, 終了ページ：35, 2017年12月, ［査読有り］, ［責任著者］
  Arabinogalactan-proteins (AGPs) are plant proteoglycans, which are widely encountered in the plant kingdom, usually localized on the cell surface. The carbohydrate moieties of AGPs consist of beta-1,3-galactan main chains and beta-1,6-galactan side chains, to which other auxiliary sugars are attached. To date, FvEn3GAL isolated from Flammulina velutipes is the sole beta-1,3-galactanase acting on beta-1,3-galactan in an endo-manner. Here we cloned two homologous genes, designated Af3G and NcEn3GAL, possibly encoding endo-beta-1,3-galactanase from Aspergillus flavus and Neurospora crassa, respectively. The recombinant Af3G (rAf3G) and rNcEn3GAL expressed in Pichia pastoris specifically hydrolyzed beta-1,3-galactan in an endo-manner, as did the rFvEn3GAL. Among galactooligosaccharides, beta-1,3-galactotriose was identified as the smallest substrate for these enzymes. These results suggest that enzymatic characteristics are conserved in many endo-beta-1,3-galactanases belonging to the glycoside hydrolase 16 family. On the other hand, rAf3G and rNcEn3GAL generated more beta-1,3-galactobiose from beta-1,3-galactotetraose than did rFvEn3GAL, suggesting that rAf3G and rNcEn3GAL prefer hydrolyzing the central beta-1,3-glycosidic linkage of three in beta-1,3-galactotetraose. Although rAf3G and rNcEn3GAL alone hardly hydrolyze native AGP, they acted synergistically with a fungal exo-beta-1,3-galactanase on the AGP. These endo-beta-1,3-galactanases presumably aid hydrolysis by internally breaking up AGPs, which creates more sites of attack for exo-beta-1,3-galactanase. (C) 2017 Elsevier Ltd. All rights reserved.
  ELSEVIER SCI LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2017.10.013
  DOI ID：10.1016/j.carres.2017.10.013, ISSN：0008-6215, eISSN：1873-426X, PubMed ID：29121496, Web of Science ID：WOS:000416212600004
• A Synthetic Glycan Microarray Enables Epitope Mapping of Plant Cell Wall Glycan-Directed Antibodies　　　　　　　　　　　　　　　
  Colin Ruprecht; Max P. Bartetzko; Deborah Senf; Pietro Dallabernadina; Irene Boos; Mathias C. F. Andersen; Toshihisa Kotake; J. Paul Knox; Michael G. Hahn; Mads H. Clausen; Fabian Pfrengle
  Plant Physiology, 巻：175, 号：3, 開始ページ：1094, 終了ページ：1104, 2017年11月, ［査読有り］
  In the last three decades, more than 200 monoclonal antibodies have been raised against most classes of plant cell wall polysaccharides by different laboratories worldwide. These antibodies are widely used to identify differences in plant cell wall components in mutants, organ and tissue types, and developmental stages. Despite their importance and broad use, the precise binding epitope has been determined for only a few of these antibodies. Here, we use a plant glycan microarray equipped with 88 synthetic oligosaccharides to comprehensively map the epitopes of plant cell wall glycan-directed antibodies. Our results reveal the binding epitopes for 78 arabinogalactan-, rhamnogalacturonan-, xylan-, and xyloglucan-directed antibodies. We demonstrate that, with knowledge of the exact epitopes recognized by individual antibodies, specific glycosyl hydrolases can be implemented into immunological cell wall analyses, providing a framework to obtain structural information on plant cell wall glycans with unprecedented molecular precision.
  AMER SOC PLANT BIOLOGISTS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.17.00737
  DOI ID：10.1104/pp.17.00737, ISSN：0032-0889, eISSN：1532-2548, PubMed ID：28924016, Web of Science ID：WOS:000414052500007
• Persistence of plant hormone levels in rice shoots grown under microgravity conditions in space: its relationship to maintenance of shoot growth　　　　　　　　　　　　　　　
  Kazuyuki Wakabayashi; Kouichi Soga; Takayuki Hoson; Toshihisa Kotake; Mikiko Kojima; Hitoshi Sakakibara; Takashi Yamazaki; Akira Higashibata; Noriaki Ishioka; Toru Shimazu; Motoshi Kamada
  Physiologia Plantarum, 巻：161, 号：2, 開始ページ：285, 終了ページ：293, 2017年10月, ［査読有り］
  We investigated the effects of microgravity environment on growth and plant hormone levels in dark-grown rice shoots cultivated in artificial 1 g and microgravity conditions on the International Space Station (ISS). Growth of microgravity-grown shoots was comparable to that of 1 g-grown shoots. Endogenous levels of indole-3-acetic acid (IAA) in shoots remained constant, while those of abscisic acid (ABA), jasmonic acid (JA), cytokinins (CKs) and gibberellins (GAs) decreased during the cultivation period under both conditions. The levels of auxin, ABA, JA, CKs and GAs in rice shoots grown under microgravity conditions were comparable to those under 1 g conditions. These results suggest microgravity environment in space had minimal impact on levels of these plant hormones in rice shoots, which may be the cause of the persistence of normal growth of shoots under microgravity conditions. Concerning ethylene, the expression level of a gene for 1-aminocyclopropane-1-carboxylic acid (ACC) synthase, the key enzyme in ethylene biosynthesis, was reduced under microgravity conditions, suggesting that microgravity may affect the ethylene production. Therefore, ethylene production may be responsive to alterations of the gravitational force.
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/ppl.12591
  DOI ID：10.1111/ppl.12591, ISSN：0031-9317, eISSN：1399-3054, PubMed ID：28573759, Web of Science ID：WOS:000417402000008
• Screening of rice mutants with improved saccharification efficiency results in the identification of CONSTITUTIVE PHOTOMORPHOGENIC 1 and GOLD HULL AND INTERNODE 1　　　　　　　　　　　　　　　
  Ko Hirano; Reiko Masuda; Wakana Takase; Yoichi Morinaka; Mayuko Kawamura; Yoshinobu Takeuchi; Hiroki Takagi; Hiroki Yaegashi; Satoshi Natsume; Ryohei Terauchi; Toshihisa Kotake; Yasuyuki Matsushita; Takashi Sazuka
  Planta, 巻：246, 号：1, 開始ページ：61, 終了ページ：74, 2017年07月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00425-017-2685-9
  DOI ID：10.1007/s00425-017-2685-9, ISSN：0032-0935, eISSN：1432-2048, PubMed ID：28357539, Web of Science ID：WOS:000404150900005
• Heterologous expression and characterization of an Arabidopsis β-L-arabinopyranosidase and α-D-galactosidases acting on β-L-arabinopyranosyl residues.　　　　　　　　　　　　　　　
  Imaizumi C; Tomatsu H; Kitazawa K; Yoshimi Y; Shibano S; Kikuchi K; Yamaguchi M; Kaneko S; Tsumuraya Y; Kotake T
  Journal of Experimental Botany, 巻：68, 号：16, 開始ページ：4651, 終了ページ：4661, 2017年07月, ［査読有り］, ［最終著者, 責任著者］
  The major plant sugar l-arabinose (L-Ara) has two different ring forms, L-arabinofuranose (L-Araf) and l-arabinopyranose (L-Arap). Although L-Ara mainly appears in the form of alpha-L-Araf residues in cell wall components, such as pectic alpha-1,3:1,5-arabinan, arabinoxylan, and arabinogalactan-proteins (AGPs), lesser amounts of it can also be found as beta-L-Arap residues of AGPs. Even though AGPs are known to be rapidly metabolized, the enzymes acting on the beta-L-Arap residues remain to be identified. In the present study, four enzymes, which we call beta-L-ARAPASE (APSE) and alpha-GALACTOSIDASE 1 (AGAL1), AGAL2, and AGAL3, are identified as those enzymes that are likely to be responsible for the hydrolysis of the beta-L-Arap residues in Arabidopsis thaliana. An Arabidopsis apse-1 mutant showed significant reduction in beta-L-arabinopyranosidase activity, and an apse-1 agal3-1 double-mutant exhibited even less activity. The apse-1 and the double-mutants both had more beta-L-Arap residues in the cell walls than wild-type plants. Recombinant APSE expressed in the yeast Pichia pastoris specifically hydrolyzed beta-L-Arap residues and released L-Ara from gum arabic and larch arabinogalactan. The recombinant AGAL3 also showed weak beta-L-arabinopyranosidase activity beside its strong alpha-galactosidase activity. It appears that the beta-L-Arap residues of AGPs are hydrolysed mainly by APSE and partially by AGALs in Arabidopsis.
  OXFORD UNIV PRESS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/jxb/erx279
  DOI ID：10.1093/jxb/erx279, ISSN：0022-0957, eISSN：1460-2431, PubMed ID：28981776, Web of Science ID：WOS:000412100500020
• A protease/peptidase from culture medium of Flammulina velutipes that acts on arabinogalactan-protein　　　　　　　　　　　　　　　
  Yoshihisa Yoshimi; Yumi Sugawara; Chiaki Hori; Kiyohiko Igarashi; Satoshi Kaneko; Yoichi Tsumuraya; Toshihisa Kotake
  Bioscience, Biotechnology and Biochemistry, 巻：81, 号：3, 開始ページ：475, 終了ページ：481, 2017年03月, ［査読有り］, ［最終著者, 責任著者］
  Arabinogalactan-proteins (AGPs) are highly diverse plant proteoglycans found on the plant cell surface. AGPs have large arabinogalactan (AG) moieties attached to a core-protein rich in hydroxyproline (Hyp). The AG undergoes hydrolysis by various glycoside hydrolases, most of which have been identified, whereas the core-proteins is presumably degraded by unknown proteases/peptidases secreted from fungi and bacteria in nature. Although several enzymes hydrolyzing other Hyp-rich proteins are known, the enzymes acting on the core-proteins of AGPs remain to be identified. The present study describes the detection of protease/peptidase activity toward AGP core-proteins in the culture medium of winter mushroom (Flammulina velutipes) and partial purification of the enzyme by several conventional chromatography steps. The enzyme showed higher activity toward Hyp residues than toward proline and alanine residues and acted on core-proteins prepared from gum arabic. Since the activity was inhibited in the presence of Pefabloc SC, the enzyme is probably a serine protease.
  TAYLOR & FRANCIS LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09168451.2016.1258985
  DOI ID：10.1080/09168451.2016.1258985, ISSN：0916-8451, eISSN：1347-6947, PubMed ID：27884087, Web of Science ID：WOS:000395102900010
• Structure and functions of arabinogalactan-proteins, a family of plant proteoglycans
  Tsumuraya, Y.; Kotake, T.
  Seikagaku, 巻：89, 号：4, 2017年
  研究論文（学術雑誌）
  DOI：https://doi.org/10.14952/SEIKAGAKU.2017.890498
  DOI ID：10.14952/SEIKAGAKU.2017.890498, ORCID：63916496, SCOPUS ID：85042885786
• Metabolism of L-arabinose in plants　　　　　　　　　　　　　　　
  Toshihisa Kotake; Yukiko Yamanashi; Chiemi Imaizumi; Yoichi Tsumuraya
  Journal of Plant Research, 巻：129, 号：5, 開始ページ：781, 終了ページ：792, 2016年09月, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］
  l-Arabinose (l-Ara) is a plant-specific sugar accounting for 5-10 % of cell wall saccharides in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). l-Ara occurs in pectic arabinan, rhamnogalacturonan II, arabinoxylan, arabinogalactan-protein (AGP), and extensin in the cell walls, as well as in glycosylated signaling peptides like CLAVATA3 and small glycoconjugates such as quercetin 3-O-arabinoside. This review focuses on recent advances towards understanding the generation of l-Ara and the metabolism of l-Ara-containing molecules in plants.
  SPRINGER JAPAN KK, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10265-016-0834-z
  DOI ID：10.1007/s10265-016-0834-z, ISSN：0918-9440, eISSN：1618-0860, PubMed ID：27220955, Web of Science ID：WOS:000381379700001
• Roles of MAP65-1 and BPP1 in gravity resistance of Arabidopsis hypocotyls　　　　　　　　　　　　　　　
  Murakami M; Soga K; Kotake T; Kato T; Hashimoto T; Wakabayashi K; Hoson T
  Biological Sciences in Space, 巻：30, 開始ページ：1, 終了ページ：7, 2016年08月, ［査読有り］
  英語
  DOI：https://doi.org/10.2187/bss.30.1
  DOI ID：10.2187/bss.30.1, ISSN：0914-9201, CiNii Articles ID：120006369769, CiNii Books ID：AN10164806
• Precise estimation of genomic regions controlling lodging resistance using a set of reciprocal chromosome segment substitution lines in rice　　　　　　　　　　　　　　　
  Taiichiro Ookawa; Ryo Aoba; Toshio Yamamoto; Tadamasa Ueda; Toshiyuki Takai; Shuichi Fukuoka; Tsuyu Ando; Shunsuke Adachi; Makoto Matsuoka; Takeshi Ebitani; Yoichiro Kato; Indria Wahyu Mulsanti; Masahiro Kishii; Matthew Reynolds; Francisco Pinera; Toshihisa Kotake; Shinji Kawasaki; Takashi Motobayashi; Tadashi Hirasawa
  Scientific Reports, 巻：6, 開始ページ：30572, 2016年07月, ［査読有り］
  Severe lodging has occurred in many improved rice varieties after the recent strong typhoons in East and Southeast Asian countries. The indica variety Takanari possesses strong culm characteristics due to its large section modulus, which indicates culm thickness, whereas the japonica variety Koshihikari is subject to substantial bending stress due to its thick cortical fibre tissue. To detect quantitative trait loci (QTLs) for lodging resistance and to eliminate the effects of genetic background, we used reciprocal chromosome segment substitution lines (CSSLs) derived from a cross between Koshihikari and Takanari. The oppositional effects of QTLs for section modulus were confirmed in both genetic backgrounds on chromosomes 1, 5 and 6, suggesting that these QTLs are not affected by the genetic background and are controlled independently by a single factor. The candidate region of a QTL for section modulus included SD1. The section modulus of NIL-sd1 was lower than that of Koshihikari, whereas the section modulus of NIL-SD1 was higher than that of Takanari. This result indicated that those regions regulate the culm thickness. The reciprocal effects of the QTLs for cortical fibre tissue thickness were confirmed in both genetic backgrounds on chromosome 9 using CSSLs.
  NATURE PUBLISHING GROUP, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/srep30572
  DOI ID：10.1038/srep30572, ISSN：2045-2322, PubMed ID：27465821, Web of Science ID：WOS:000380975700001
• The AMOR Arabinogalactan Sugar Chain Induces Pollen-Tube Competency to Respond to Ovular Guidance.　　　　　　　　　　　　　　　
  Akane G Mizukami; Rie Inatsugi; Jiao Jiao; Toshihisa Kotake; Keiko Kuwata; Kento Ootani; Satohiro Okuda; Subramanian Sankaranarayanan; Yoshikatsu Sato; Daisuke Maruyama; Hiroaki Iwai; Estelle Garénaux; Chihiro Sato; Ken Kitajima; Yoichi Tsumuraya; Hitoshi Mori; Junichiro Yamaguchi; Kenichiro Itami; Narie Sasaki; Tetsuya Higashiyama
  Current Biology : CB, 巻：26, 号：8, 開始ページ：1091, 終了ページ：7, 2016年04月, ［査読有り］, ［国際誌］
  Precise directional control of pollen-tube growth by pistil tissue is critical for successful fertilization of flowering plants [1-3]. Ovular attractant peptides, which are secreted from two synergid cells on the side of the egg cell, have been identified [4-6]. Emerging evidence suggests that the ovular directional cue is not sufficient for successful guidance but that competency control by the pistil is critical for the response of pollen tubes to the attraction signal [1, 3, 7]. However, the female molecule for this competency induction has not been reported. Here we report that ovular methyl-glucuronosyl arabinogalactan (AMOR) induces competency of the pollen tube to respond to ovular attractant LURE peptides in Torenia fournieri. We developed a method for assaying the response capability of a pollen tube by micromanipulating an ovule. Using this method, we showed that pollen tubes growing through a cut style acquired a response capability in the medium by receiving a sufficient amount of a factor derived from mature ovules of Torenia. This factor, named AMOR, was identified as an arabinogalactan polysaccharide, the terminal 4-O-methyl-glucuronosyl residue of which was necessary for its activity. Moreover, a chemically synthesized disaccharide, the β isomer of methyl-glucuronosyl galactose (4-Me-GlcA-β-(1→6)-Gal), showed AMOR activity. No specific sugar-chain structure of plant extracellular matrix has been identified as a bioactive molecule involved in intercellular communication. We suggest that the AMOR sugar chain in the ovary renders the pollen tube competent to the chemotropic response prior to final guidance by LURE peptides.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.cub.2016.02.040
  DOI ID：10.1016/j.cub.2016.02.040, ISSN：0960-9822, PubMed ID：27068416
• KONJAC1 and 2 Are Key Factors for GDP-Mannose Generation and Affect L-Ascorbic Acid and Glucomannan Biosynthesis in Arabidopsis　　　　　　　　　　　　　　　
  Shota Sawake; Noriaki Tajima; Jenny C. Mortimer; Jeemeng Lao; Toshiki Ishikawa; Xiaolan Yu; Yukiko Yamanashi; Yoshihisa Yoshimi; Maki Kawai-Yamada; Paul Dupree; Yoichi Tsumuraya; Toshihisa Kotake
  Plant Cell, 巻：27, 号：12, 開始ページ：3397, 終了ページ：3409, 2015年12月, ［査読有り］, ［最終著者, 責任著者］
  Humans are unable to synthesize L-ascorbic acid (AsA), yet it is required as a cofactor in many critical biochemical reactions. The majority of human dietary AsA is obtained from plants. In Arabidopsis thaliana, a GDP-mannose pyrophosphorylase (GMPP), VITAMIN C DEFECTIVE1 (VTC1), catalyzes a rate-limiting step in AsA synthesis: the formation of GDP-Man. In this study, we identified two nucleotide sugar pyrophosphorylase-like proteins, KONJAC1 (KJC1) and KJC2, which stimulate the activity of VTC1. The kjc1kjc2 double mutant exhibited severe dwarfism, indicating that KJC proteins are important for growth and development. The kjc1 mutation reduced GMPP activity to 10% of wild-type levels, leading to a 60% reduction in AsA levels. On the contrary, overexpression of KJC1 significantly increased GMPP activity. The kjc1 and kjc1kjc2 mutants also exhibited significantly reduced levels of glucomannan, which is also synthesized from GDP-Man. Recombinant KJC1 and KJC2 enhanced the GMPP activity of recombinant VTC1 in vitro, while KJCs did not show GMPP activity. Yeast two-hybrid assays suggested that the stimulation of GMPP activity occurs via interaction of KJCs with VTC1. These results suggest that KJCs are key factors for the generation of GDP-Man and affect AsA level and glucomannan accumulation through the stimulation of VTC1 GMPP activity.
  AMER SOC PLANT BIOLOGISTS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1105/tpc.15.00379
  DOI ID：10.1105/tpc.15.00379, ISSN：1040-4651, eISSN：1532-298X, PubMed ID：26672069, Web of Science ID：WOS:000368297100010
• l-Fucose-containing arabinogalactan-protein in radish leaves　　　　　　　　　　　　　　　
  Miho Inaba; Takuma Maruyama; Yoshihisa Yoshimi; Toshihisa Kotake; Koji Matsuoka; Tetsuo Koyama; Theodora Tryfona; Paul Dupree; Yoichi Tsumuraya
  Carbohydrate Research, 巻：415, 開始ページ：1, 終了ページ：11, 2015年10月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2015.07.002
  DOI ID：10.1016/j.carres.2015.07.002, ISSN：0008-6215, eISSN：1873-426X, PubMed ID：26267887, Web of Science ID：WOS:000362889100001
• Suppression of Hydroxycinnamate Network Formation in Cell Walls of Rice Shoots Grown under Microgravity Conditions in Space　　　　　　　　　　　　　　　
  Kazuyuki Wakabayashi; Kouichi Soga; Takayuki Hoson; Toshihisa Kotake; Takashi Yamazaki; Akira Higashibata; Noriaki Ishioka; Toru Shimazu; Keiji Fukui; Ikuko Osada; Haruo Kasahara; Motoshi Kamada
  PLoS One, 巻：10, 号：9, 開始ページ：e0137992, 2015年09月, ［査読有り］
  Network structures created by hydroxycinnamate cross-links within the cell wall architecture of gramineous plants make the cell wall resistant to the gravitational force of the earth. In this study, the effects of microgravity on the formation of cell wall-bound hydroxycinnamates were examined using etiolated rice shoots simultaneously grown under artificial 1 g and microgravity conditions in the Cell Biology Experiment Facility on the International Space Station. Measurement of the mechanical properties of cell walls showed that shoot cell walls became stiff during the growth period and that microgravity suppressed this stiffening. Amounts of cell wall polysaccharides, cell wall-bound phenolic acids, and lignin in rice shoots increased as the shoot grew. Microgravity did not influence changes in the amounts of cell wall polysaccharides or phenolic acid monomers such as ferulic acid (FA) and p-coumaric acid, but it suppressed increases in diferulic acid (DFA) isomers and lignin. Activities of the enzymes phenylalanine ammonia-lyase (PAL) and cell wall-bound peroxidase (CW-PRX) in shoots also increased as the shoot grew. PAL activity in microgravity-grown shoots was almost comparable to that in artificial 1 g-grown shoots, while CW-PRX activity increased less in microgravity-grown shoots than in artificial 1 g-grown shoots. Furthermore, the increases in expression levels of some class III peroxidase genes were reduced under microgravity conditions. These results suggest that a microgravity environment modifies the expression levels of certain class III peroxidase genes in rice shoots, that the resultant reduction of CW-PRX activity may be involved in suppressing DFA formation and lignin polymerization, and that this suppression may cause a decrease in cross-linkages within the cell wall architecture. The reduction in intra-network structures may contribute to keeping the cell wall loose under microgravity conditions.
  PUBLIC LIBRARY SCIENCE, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1371/journal.pone.0137992
  DOI ID：10.1371/journal.pone.0137992, ISSN：1932-6203, PubMed ID：26378793, Web of Science ID：WOS:000361769400042
• Hormonal regulation of gummosis and composition of gums from bulbs of hyacinth (Hyacinthus orientalis)　　　　　　　　　　　　　　　
  Kensuke Miyamoto; Toshihisa Kotake; Anna Jarecka Boncela; Marian Saniewski; Junichi Ueda
  Journal of Plant Physiology, 巻：174, 開始ページ：1, 終了ページ：4, 2015年02月, ［査読有り］
  Hyacinth (Hyacinthus orientalis) bulbs infected by Fusarium oxysporum showed the symptoms of gummosis. The purpose of this study was to clarify the hormonal regulation of gummosis and composition of gums from hyacinth bulbs. The application of ethephon (2-chloroethylphosphonic acid), an ethylene-releasing compound, at 2% (w/w, in lanolin) induced gummosis in hyacinth bulbs. Methyl jasmonate (JA-Me) at 1.5% (w/w, in lanolin) induced gummosis as well. Simultaneous application of JA-Me and ethephon further enhanced gummosis. Molecular mass distribution of hyacinth gums analyzed by gel permeation chromatography indicated that the gums were mainly homogenous polysaccharides with an average molecular weight of ca. 30 kDa. Analysis of the sugar composition of the gums after hydrolysis revealed that the majority were arabinose (ca. 35%) and galactose (ca. 40%) together with small amounts of fucose, rhamnose and uronic acids (ca. 5%, respectively), suggesting that the gums are pectic arabinogalactans. These results indicate that jasmonates (JAs) interact with ethylene to stimulate sugar metabolism, producing pectic arabinogalactans, and vice versa, leading to gummosis. These findings, together with those from our previous studies in tulips (Tulipa gesneriana) and grape hyacinth (Muscari armeniacum), revealed that sugar metabolism and hormonal regulation relating to gummosis are different among species of bulbous plants. (C) 2014 Elsevier GmbH. All rights reserved.
  ELSEVIER GMBH, URBAN & FISCHER VERLAG, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jplph.2014.10.007
  DOI ID：10.1016/j.jplph.2014.10.007, ISSN：0176-1617, eISSN：1618-1328, PubMed ID：25462960, Web of Science ID：WOS:000346488700001
• Action of an endo-β-1,3(4)-glucanase on cellobiosyl unit structure in barley β-1,3:1,4-glucan.　　　　　　　　　　　　　　　
  Kuge T; Nagoya H; Tryfona T; Kurokawa T; Yoshimi Y; Dohmae N; Tsubaki K; Dupree P; Tsumuraya Y; Kotake T
  Bioscience, Biotechnology, and Biochemistry, 巻：79, 号：11, 開始ページ：1810, 終了ページ：1817, 2015年, ［査読有り］
  beta-1,3:1,4-Glucan is a major cell wall component accumulating in endosperm and young tissues in grasses. The mixed linkage glucan is a linear polysaccharide mainly consisting of cellotriosyl and cellotetraosyl units linked through single beta-1,3glucosidic linkages, but it also contains minor structures such as cellobiosyl units. In this study, we examined the action of an endo-beta-1,3(4)-glucanase from Trichoderma sp. on a minor structure in barley beta-1,3:1,4-glucan. To find the minor structure on which the endo-beta-1,3(4)-glucanase acts, we prepared oligosaccharides from barley beta-1,3:1,4-glucan by endo-beta-1,4-glucanase digestion followed by purification by gel permeation and paper chromatography. The endo-beta-1,3(4)-glucanase appeared to hydrolyze an oligosaccharide with degree of polymerization 5, designated C5-b. Based on matrix-assisted laser desorption/ionization (MALDI) time-of-flight (ToF)/ToF-mass spectrometry (MS)/MS analysis, C5-b was identified as beta-Glc-1,3-beta-Glc-1,4-beta-Glc-1,3-beta-Glc-1,4-Glc including a cellobiosyl unit. The results indicate that a type of endo-beta-1,3(4)-glucanase acts on the cellobiosyl units of barley beta-1,3:1,4-glucan in an endo-manner.
  TAYLOR & FRANCIS LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09168451.2015.1046365
  DOI ID：10.1080/09168451.2015.1046365, ISSN：0916-8451, eISSN：1347-6947, PubMed ID：26027730, Web of Science ID：WOS:000371305900009
• Enzymatic activity and substrate specificity of the recombinant tomato β-galactosidase 1.　　　　　　　　　　　　　　　
  Eda M; Ishimaru M; Tada T; Sakamoto T; Kotake T; Tsumuraya Y; Mort AJ; Gross KC
  Journal of Plant Physiology, 巻：171, 号：16, 開始ページ：1454, 終了ページ：1460, 2014年10月, ［査読有り］
  The open reading frame of tomato beta-galactosidase 1 was expressed in yeast, and the enzymatic properties and substrate specificity were investigated. The enzyme had peak activity at pH 5.0 and 40-50 degrees C. TBG1 was active on beta-(1,3)- and beta-(1,6)-galactobiose and lactose. TBG1 released galactose from lupin galactan, tomato fruit alkali soluble pectin, arabinogalactan, gum arabic and methyl beta-(1,6)-galactohexaoside, but not from labeled beta-(1,4)-galactoheptaose. TBG1 was assessed for its ability to degrade three galactosyl-containing cell wall fractions purified from different development and ripening stages of tomato fruit. TBG1 released galactose from all of the fractions from all of the stages tested. TBG1 activity was highest on the hemicellulose fraction at the 10 and 20 d after pollination stage. This result is not correlated the with TBG1 expression pattern. TBG1 might act on a small but specific set of polysaccharide containing galactose. (C) 2014 Elsevier GmbH. All rights reserved.
  ELSEVIER GMBH, URBAN & FISCHER VERLAG, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jplph.2014.06.010
  DOI ID：10.1016/j.jplph.2014.06.010, ISSN：0176-1617, eISSN：1618-1328, PubMed ID：25105231, Web of Science ID：WOS:000345632200001
• Enzymatic fragmentation of carbohydrate moieties of radish arabinogalactan-protein and elucidation of the structures　　　　　　　　　　　　　　　
  Ryohei Shimoda; Kohei Okabe; Toshihisa Kotake; Koji Matsuoka; Tetsuo Koyama; Theodora Tryfona; Hui-Chung Liang; Paul Dupree; Yoichi Tsumuraya
  Bioscience, Biotechnology, and Biochemistry, 巻：78, 号：5, 開始ページ：818, 終了ページ：831, 2014年05月, ［査読有り］
  Abstract
  
  We investigated the structures of L-arabino-galactooligosaccharides released from the sugar moieties of a radish arabinogalactan-protein (AGP) by the action of exo-β-(1→3)-galactanase. We detected a series of neutral β-(1→6)-linked galactooligosaccharides forming branches of one to up to at least 19 consecutive Gal groups, together with corresponding acidic derivatives terminating in 4-O-methyl-glucuronic acid (4-Me-GlcA) at the non-reducing end. Some oligosaccharide chains of degree of polymerization (dp) higher than 3 for neutral, and 4 for acidic oligomers were modified with L-Araf residues. The acidic tetrasaccharide 4-Me-β-GlcA-(1→6)[α-L-Araf-(1→3)]-β-Gal-(1→6)-Gal was detected as an abundant L-Araf-containing oligosaccharide among these neutral and acidic oligomers. A pentasaccharide containing an additional L-Araf group attached to the L-Ara in the tetrasaccharide through an α-(1→5)-linkage was also found. We observed L-arabino-galactooligosaccharides substituted with single or disaccharide L-Araf units at different Gal residues along these neutral and acidic β-(1→6)-galactooligosaccharide chains, indicating that these side chains are highly variable in length and substituted variously with L-Araf residues.
  Informa UK Limited, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/09168451.2014.910100
  DOI ID：10.1080/09168451.2014.910100, ISSN：0916-8451, eISSN：1347-6947, PubMed ID：25035985, Web of Science ID：WOS:000339070600015
• Characterization of alkali-soluble polysaccharides in deep subsoil layers　　　　　　　　　　　　　　　
  Toshihisa Kotake; Shoichiro Hamamoto; Takeshi Saito; Junichi Ohnishi; Toshiko Komatsu; Yoichi Tsumuraya
  Soil Science and Plant Nutrition, 巻：59, 号：6, 開始ページ：871, 終了ページ：876, 2013年12月, ［査読有り］
  Plant cell wall polysaccharides undergo a slower degradation process in deep subsoil layers than in topsoil. Through the identification of organic compounds in subsoil, we may gain an understanding of this degradation process. In the present study, we extracted alkali-soluble polysaccharides from subsoil bore samples at depths of 5, 18, 29, 35 and 40-43m, and performed sugar composition and sugar linkage analyses. Based on the results, we suggest that cellulose, arabinoxylan, mannan and pectic polysaccharides derived from plant cell walls and -1,3-glucan and/or -1,3:1,6-glucan from fungal cell walls exist in deep subsoil layers.
  TAYLOR & FRANCIS LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1080/00380768.2013.853280
  DOI ID：10.1080/00380768.2013.853280, ISSN：0038-0768, eISSN：1747-0765, Web of Science ID：WOS:000328245100005
• Biosynthesis of the carbohydrate moieties of arabinogalactan proteins by membrane-bound β-glucuronosyltransferases from radish primary roots.　　　　　　　　　　　　　　　
  Endo M; Kotake T; Watanabe Y; Kimura K; Tsumuraya Y
  Planta, 巻：238, 号：6, 開始ページ：1157, 終了ページ：1169, 2013年12月, ［査読有り］
  A membrane fraction from etiolated 6-day-old primary radish roots (Raphanus sativus L. var hortensis) contained beta-glucuronosyltransferases (GlcATs) involved in the synthesis of the carbohydrate moieties of arabinogalactan proteins (AGPs). The GlcATs transferred [C-14]GlcA from UDP-[C-14]GlcA on to beta-(1 -> 3)-galactan as an exogenous acceptor substrate, giving a specific activity of 50-150 pmol min(-1) (mg protein)(-1). The enzyme specimen also catalyzed the transfer of [C-14]GlcA on to an enzymatically modified AGP from mature radish root. Analysis of the transfer products revealed that the transfer of [C-14]GlcA occurred preferentially on to consecutive (1 -> 3)-linked beta-Gal chains as well as single branched beta-(1 -> 6)-Gal residues through beta-(1 -> 6) linkages, producing branched acidic side chains. The enzymes also transferred [C-14]GlcA residues on to several oligosaccharides, such as beta-(1 -> 6)- and beta-(1 -> 3)-galactotrioses. A trisaccharide, alpha-l-Araf-(1 -> 3)-beta-Gal-(1 -> 6)-Gal, was a good acceptor, yielding a branched tetrasaccharide, alpha-l-Araf-(1 -> 3)[beta-GlcA-(1 -> 6)]-beta-Gal-(1 -> 6)-Gal. We report the first in vitro assay system for beta-GlcATs involved in the AG synthesis as a step toward full characterization and cloning.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00425-013-1959-0
  DOI ID：10.1007/s00425-013-1959-0, ISSN：0032-0935, eISSN：1432-2048, PubMed ID：24057431, Web of Science ID：WOS:000327386200012
• A β-glucuronosyltransferase from Arabidopsis thaliana involved in biosynthesis of type II arabinogalactan has a role in cell elongation during seedling growth.　　　　　　　　　　　　　　　
  Knoch E; Dilokpimol A; Tryfona T; Poulsen CP; Xiong G; Harholt J; Petersen BL; Ulvskov P; Hadi MZ; Kotake T; Tsumuraya Y; Pauly M; Dupree P; Geshi N
  Plant Journal, 巻：76, 号：6, 開始ページ：1016, 終了ページ：1029, 2013年12月, ［査読有り］
  We have characterized a -glucuronosyltransferase (AtGlcAT14A) from Arabidopsis thaliana that is involved in the biosynthesis of typeII arabinogalactan (AG). This enzyme belongs to the Carbohydrate Active Enzyme database glycosyltransferase family14 (GT14). The protein was localized to the Golgi apparatus when transiently expressed in Nicotiana benthamiana. The soluble catalytic domain expressed in Pichia pastoris transferred glucuronic acid (GlcA) to -1,6-galactooligosaccharides with degrees of polymerization (DP) ranging from 3-11, and to -1,3-galactooligosaccharides of DP5 and 7, indicating that the enzyme is a glucuronosyltransferase that modifies both the -1,6- and -1,3-galactan present in typeII AG. Two allelic T-DNA insertion mutant lines showed 20-35% enhanced cell elongation during seedling growth compared to wild-type. Analyses of AG isolated from the mutants revealed a reduction of GlcA substitution on Gal--1,6-Gal and -1,3-Gal, indicating an in vivo role of AtGlcAT14A in synthesis of those structures in typeII AG. Moreover, a relative increase in the levels of 3-, 6- and 3,6-linked galactose (Gal) and reduced levels of 3-, 2- and 2,5-linked arabinose (Ara) were seen, suggesting that the mutation in AtGlcAT14A results in a relative increase of the longer and branched -1,3- and -1,6-galactans. This increase of galactosylation in the mutants is most likely caused by increased availability of the O6 position of Gal, which is a shared acceptor site for AtGlcAT14A and galactosyltransferases in synthesis of typeII AG, and thus addition of GlcA may terminate Gal chain extension. We discuss a role for the glucuronosyltransferase in the biosynthesis of typeII AG, with a biological role during seedling growth.
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/tpj.12353
  DOI ID：10.1111/tpj.12353, ISSN：0960-7412, eISSN：1365-313X, PubMed ID：24128328, Web of Science ID：WOS:000328014300009
• A galactosyltransferase acting on arabinogalactan protein glycans is essential for embryo development in Arabidopsis　　　　　　　　　　　　　　　
  Naomi Geshi; Jorunn N. Johansen; Adiphol Dilokpimol; Aurélia Rolland; Katia Belcram; Stéphane Verger; Toshihisa Kotake; Yoichi Tsumuraya; Satoshi Kaneko; Theodora Tryfona; Paul Dupree; Henrik V. Scheller; Herman Höfte; Gregory Mouille
  Plant Journal, 巻：76, 号：1, 開始ページ：128, 終了ページ：137, 2013年10月, ［査読有り］
  Arabinogalactan proteins (AGPs) are a complex family of cell-wall proteoglycans that are thought to play major roles in plant growth and development. Genetic approaches to studying AGP function have met limited success so far, presumably due to redundancy within the large gene families encoding AGP backbones. Here we used an alternative approach for genetic dissection of the role of AGPs in development by modifying their glycan side chains. We have identified an Arabidopsis glycosyltransferase of CAZY family GT31 (AtGALT31A) that galactosylates AGP side chains. A mutation in the AtGALT31A gene caused the arrest of embryo development at the globular stage. The presence of the transcript in the suspensor of globular-stage embryos is consistent with a role for AtGALT31A in progression of embryo development beyond the globular stage. The first observable defect in the mutant is perturbation of the formative asymmetric division of the hypophysis, indicating an essential role for AGP proteoglycans in either specification of the hypophysis or orientation of the asymmetric division plane. © 2013 The Authors The Plant Journal © 2013 John Wiley &
  Sons Ltd.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/tpj.12281
  DOI ID：10.1111/tpj.12281, ISSN：0960-7412, PubMed ID：23837821, SCOPUS ID：84884903407
• β-galactosyl Yariv reagent binds to the β-1,3-galactan of arabinogalactan proteins.　　　　　　　　　　　　　　　
  Kitazawa K; Tryfona T; Yoshimi Y; Hayashi Y; Kawauchi S; Antonov L; Tanaka H; Takahashi T; Kaneko S; Dupree P; Tsumuraya Y; Kotake T
  Plant Physiology, 巻：161, 号：3, 開始ページ：1117, 終了ページ：1126, 2013年03月, ［査読有り］, ［最終著者, 責任著者］
  Yariv phenylglycosides [1,3,5-tri(p-glycosyloxyphenylazo)-2,4,6-trihydroxybenzene] are a group of chemical compounds that selectively bind to arabinogalactan proteins (AGPs), a type of plant proteoglycan. Yariv phenylglycosides are widely used as cytochemical reagents to perturb the molecular functions of AGPs as well as for the detection, quantification, purification, and staining of AGPs. However, the target structure in AGPs to which Yariv phenylglycosides bind has not been determined. Here, we identify the structural element of AGPs required for the interaction with Yariv phenylglycosides by stepwise trimming of the arabinogalactan moieties using combinations of specific glycoside hydrolases. Whereas the precipitation with Yariv phenylglycosides (Yariv reactivity) of radish (Raphanus sativus) root AGP was not reduced after enzyme treatment to remove a-L-arabinofuranosyl and beta-glucuronosyl residues and beta-1,6-galactan side chains, it was completely lost after degradation of the beta-1,3-galactan main chains. In addition, Yariv reactivity of gum arabic, a commercial product of acacia (Acacia senegal) AGPs, increased rather than decreased during the repeated degradation of beta-1,6-galactan side chains by Smith degradation. Among various oligosaccharides corresponding to partial structures of AGPs, beta-1,3-galactooligosaccharides longer than beta-1,3-galactoheptaose exhibited significant precipitation with Yariv in a radial diffusion assay on agar. A pull-down assay using oligosaccharides cross linked to hydrazine beads detected an interaction of beta-1,3-galactooligosaccharides longer than beta-1,3-galactopentaose with Yariv phenylglycoside. To the contrary, no interaction with Yariv was detected for beta-1,6-galactooligosaccharides of any length. Therefore, we conclude that Yariv phenylglycosides should be considered specific binding reagents for beta-1,3-galactan chains longer than five residues, and seven residues are sufficient for cross linking, leading to precipitation of the Yariv phenylglycosides.
  AMER SOC PLANT BIOLOGISTS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.112.211722
  DOI ID：10.1104/pp.112.211722, ISSN：0032-0889, PubMed ID：23296690, Web of Science ID：WOS:000316984100007
• Structural Characterization of Arabidopsis Leaf Arabinogalactan Polysaccharides　　　　　　　　　　　　　　　
  Theodora Tryfona; Hui-Chung Liang; Toshihisa Kotake; Yoichi Tsumuraya; Elaine Stephens; Paul Dupree
  Plant Physiology, 巻：160, 号：2, 開始ページ：653, 終了ページ：666, 2012年10月, ［査読有り］
  Proteins decorated with arabinogalactan (AG) have important roles in cell wall structure and plant development, yet the structure and biosynthesis of this polysaccharide are poorly understood. To facilitate the analysis of biosynthetic mutants, water-extractable arabinogalactan proteins (AGPs) were isolated from the leaves of Arabidopsis (Arabidopsis thaliana) plants and the structure of the AG carbohydrate component was studied. Enzymes able to hydrolyze specifically AG were utilized to release AG oligosaccharides. The released oligosaccharides were characterized by high-energy matrix-assisted laser desorption ionization-collision-induced dissociation mass spectrometry and polysaccharide analysis by carbohydrate gel electrophoresis. The Arabidopsis AG is composed of a beta-(1 -> 3)-galactan backbone with beta-(1 -> 6)-D-galactan side chains. The beta-(1 -> 6)-galactan side chains vary in length from one to over 20 galactosyl residues, and they are partly substituted with single alpha-(1 -> 3)-L-arabinofuranosyl residues. Additionally, a substantial proportion of the beta-(1 -> 6)-galactan side chain oligosaccharides are substituted at the nonreducing termini with single 4-O-methyl-glucuronosyl residues via beta-(1 -> 6)-linkages. The beta-(1 -> 6)-galactan side chains are occasionally substituted with alpha-L-fucosyl. In the fucose-deficient murus1 mutant, AGPs lack these fucose modifications. This work demonstrates that Arabidopsis mutants in AGP structure can be identified and characterized. The detailed structural elucidation of the AG polysaccharides from the leaves of Arabidopsis is essential for insights into the structure-function relationships of these molecules and will assist studies on their biosynthesis.
  AMER SOC PLANT BIOLOGISTS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.112.202309
  DOI ID：10.1104/pp.112.202309, ISSN：0032-0889, PubMed ID：22891237, Web of Science ID：WOS:000309523800008
• The role of extracellular polysaccharides produced by the terrestrial cyanobacterium Nostoc sp strain HK-01 in NaCl tolerance　　　　　　　　　　　　　　　
  Hidehisa Yoshimura; Toshihisa Kotake; Tsutomu Aohara; Yoichi Tsumuraya; Masahiko Ikeuchi; Masayuki Ohmori
  Journal of Applied Phycology, 巻：24, 号：2, 開始ページ：237, 終了ページ：243, 2012年04月, ［査読有り］
  The terrestrial cyanobacterium Nostoc sp. HK-01 was more tolerant to NaCl stress than the aquatic cyanobacterium Anabaena sp. PCC 7120 (also called Nostoc sp. PCC 7120) which is similar to Nostoc sp. HK-01 in phylogeny. We determined the amount of extracellular polysaccharides (capsular and released polysaccharides) from the cells of both strains cultured with or without 200 mM NaCl. The amount of capsular polysaccharides from Nostoc HK-01 reached approximately 65% of the dry weight whereas that from Anabaena PCC 7120 only occupied approximately 18% of the dry weight under NaCl stress. Anabaena PCC 7120 grew well under NaCl stress when both polysaccharides from Nostoc HK-01 were added to the culture. However, Anabaena PCC 7120 barely grew under NaCl stress when both of its polysaccharides were added. Extracellular polysaccharides from Nostoc HK-01 contained abundant fucose and glucuronic acid in comparison with those from Anabaena PCC 7120. Under NaCl stress, the composition ratios of sugars in the extracellular polysaccharides from Anabaena PCC 7120 hardly changed in comparison with those in ordinary culture conditions. By contrast, the composition ratios of sugars in the extracellular polysaccharides from Nostoc HK-01 changed under NaCl stress. These results suggest that the effect of extracellular polysaccharides from Nostoc HK-01 on NaCl tolerance comes from the increased amount of capsular polysaccharides, the sugar composition, and the change of the sugar composition ratio under NaCl stress.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10811-011-9672-5
  DOI ID：10.1007/s10811-011-9672-5, ISSN：0921-8971, Web of Science ID：WOS:000300888200010
• Structural and biochemical characterization of glycoside hydrolase family 79 β-glucuronidase from Acidobacterium capsulatum.　　　　　　　　　　　　　　　
  Michikawa M; Ichinose H; Momma M; Biely P; Jongkees S; Yoshida M; Kotake T; Tsumuraya Y; Withers SG; Fujimoto Z; Kaneko S
  Journal of Biological Chemistry, 巻：287, 号：17, 開始ページ：14069, 終了ページ：14077, 2012年04月, ［査読有り］
  We present the first structure of a glycoside hydrolase family 79 beta-glucuronidase from Acidobacterium capsulatum, both as a product complex with beta-D-glucuronic acid (GlcA) and as its trapped covalent 2-fluoroglucuronyl intermediate. This enzyme consists of a catalytic (beta/alpha)(8)-barrel domain and a beta-domain with irregular Greek key motifs that is of unknown function. The enzyme showed beta-glucuronidase activity and trace levels of beta-glucosidase and beta-xylosidase activities. In conjunction with mutagenesis studies, these structures identify the catalytic residues as Glu(173) (acid base) and Glu(287) (nucleophile), consistent with the retaining mechanism demonstrated by H-1 NMR analysis. Glu(45), Tyr(243), Tyr(292)-Gly(294), and Tyr(334) form the catalytic pocket and provide substrate discrimination. Consistent with this, the Y292A mutation, which affects the interaction between the main chains of Gln(293) and Gly(294) and the GlcA carboxyl group, resulted in significant loss of beta-glucuronidase activity while retaining the side activities at wild-type levels. Likewise, although the beta-glucuronidase activity of the Y334F mutant is similar to 200-fold lower (k(cat)/K-m) than that of the wild-type enzyme, the beta-glucosidase activity is actually 3 times higher and the beta-xylosidase activity is only 2.5-fold lower than the equivalent parameters for wild type, consistent with a role for Tyr(334) in recognition of the C6 position of GlcA. The involvement of Glu(45) in discriminating against binding of the O-methyl group at the C4 position of GlcA is revealed in the fact that the E45D mutant hydrolyzes PNP-beta-GlcA approximately 300-fold slower (k(cat)/K-m) than does the wild-type enzyme, whereas 4-O-methyl-GlcA-containing oligosaccharides are hydrolyzed only 7-fold slower.
  AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.M112.346288
  DOI ID：10.1074/jbc.M112.346288, ISSN：0021-9258, PubMed ID：22367201, Web of Science ID：WOS:000303996300060
• Changes in the transcript levels of microtubule-associated protein MAP65-1 during reorientation of cortical microtubules in azuki bean epicotyls　　　　　　　　　　　　　　　
  Soga, Kouichi; Kotake; Toshihisa; Wakabayashi, Kazuyuki; Hoson, Takayuki
  Acta Physiologiae Plantarum, 巻：34, 号：2, 開始ページ：533, 終了ページ：540, 2012年03月, ［査読有り］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s11738-011-0850-5
  DOI ID：10.1007/s11738-011-0850-5, ISSN：0137-5881, ORCID：20757413, Web of Science ID：WOS:000300453500014
• Endo-beta-1,3-galactanase from Winter Mushroom Flammulina velutipes　　　　　　　　　　　　　　　
  Toshihisa Kotake; Naohiro Hirata; Yuta Degi; Maki Ishiguro; Kiminari Kitazawa; Ryohei Takata; Hitomi Ichinose; Satoshi Kaneko; Kiyohiko Igarashi; Masahiro Samejima; Yoichi Tsumuraya
  Journal of Biological Chemistry, 巻：286, 号：31, 開始ページ：27848, 終了ページ：27854, 2011年08月, ［査読有り］, ［筆頭著者, 責任著者］
  Arabinogalactan proteins are proteoglycans found on the cell surface and in the cell walls of higher plants. The carbohydrate moieties of most arabinogalactan proteins are composed of beta-1,3-galactan main chains and beta-1,6-galactan side chains, to which other auxiliary sugars are attached. For the present study, an endo-beta-1,3-galactanase, designated FvEn3GAL, was first purified and cloned from winter mushroom Flammulina velutipes. The enzyme specifically hydrolyzed beta-1,3-galactan, but didnot act on beta-1,3-glucan, beta-1,3: 1,4-glucan, xyloglucan, and agarose. It released various beta-1,3-galactooligosaccharides together with Gal from beta-1,3-galactohexaose in the early phase of the reaction, demonstrating that it acts on beta-1,3-galactan in an endo-fashion. Phylogenetic analysis revealed that FvEn3GAL is member of a novel subgroup distinct from known glycoside hydrolases such as endo-beta-1,3-glucanase and endo-beta-1,3: 1,4-glucanase in glycoside hydrolase family 16. Point mutations replacing the putative catalytic Glu residues conserved for enzymes in this family with Asp abolished activity. These results indicate that FvEn3GAL is a highly specific glycoside hydrolase 16 endo-beta-1,3-galactanase.
  AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.M111.251736
  DOI ID：10.1074/jbc.M111.251736, ISSN：0021-9258, PubMed ID：21653698, Web of Science ID：WOS:000293268700076
• Rice Brittle culm 6 encodes a dominant-negative form of CesA protein that perturbs cellulose synthesis in secondary cell walls　　　　　　　　　　　　　　　
  Toshihisa Kotake; Tsutomu Aohara; Ko Hirano; Ami Sato; Yasuko Kaneko; Yoichi Tsumuraya; Hiroshi Takatsuji; Shinji Kawasaki
  Journal of Experimental Botany, 巻：62, 号：6, 開始ページ：2053, 終了ページ：2062, 2011年03月, ［査読有り］, ［筆頭著者］
  The brittle culm (bc) mutants of Gramineae plants having brittle skeletal structures are valuable materials for studying secondary cell walls. In contrast to other recessive bc mutants, rice Bc6 is a semi-dominant bc mutant with easily breakable plant bodies. In this study, the Bc6 gene was cloned by positional cloning. Bc6 encodes a cellulose synthase catalytic subunit, OsCesA9, and has a missense mutation in its highly conserved region. In culms of the Bc6 mutant, the proportion of cellulose was reduced by 38%, while that of hemicellulose was increased by 34%. Introduction of the semi-dominant Bc6 mutant gene into wild-type rice significantly reduced the percentage of cellulose, causing brittle phenotypes. Transmission electron microscopy analysis revealed that Bc6 mutation reduced the cell wall thickness of sclerenchymal cells in culms. In rice expressing a reporter construct, BC6 promoter activity was detected in the culms, nodes, and flowers, and was localized primarily in xylem tissues. This expression pattern was highly similar to that of BC1, which encodes a COBRA-like protein involved in cellulose synthesis in secondary cell walls in rice. These results indicate that BC6 is a secondary cell wall-specific CesA that plays an important role in proper deposition of cellulose in the secondary cell walls.
  OXFORD UNIV PRESS, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/jxb/erq395
  DOI ID：10.1093/jxb/erq395, ISSN：0022-0957, PubMed ID：21209026, Web of Science ID：WOS:000288553000026
• Carbohydrate structural analysis of wheat flour arabinogalactan protein　　　　　　　　　　　　　　　
  Theodora Tryfona; Hui-Chung Liang; Toshihisa Kotake; Satoshi Kaneko; Justin Marsh; Hitomi Ichinose; Alison Lovegrove; Yoichi Tsumuraya; Peter R. Shewry; Elaine Stephens; Paul Dupree
  Carbohydrate Research, 巻：345, 号：18, 開始ページ：2648, 終了ページ：2656, 2010年12月, ［査読有り］
  The water-extractable arabinogalactan protein (AGP) was isolated from bread wheat flour (Triticum aestivum L variety Cadenza) and the structure of the arabinogalactan (AG) carbohydrate component was studied Oligosaccharides released by hydrolysis of the AG with a range of ACP-specific enzymes were characterised by Matrix Assisted Laser Desorption Ionisation (MALDI)-Time of Flight (ToF)-Mass Spectrometry (MS) MALDI-ToF/ToF high energy collision induced dissociation (CID) and Polysaccharide Analysis by Carbohydrate gel Electrophoresis (PACE) The AG is composed of a beta-(1 -> 3)-D-galactan backbone with beta-(1 -> 6)-D-galactan side chains These side chains are highly variable in length from one to at least 20 Gal residues and are highly substituted with alpha-L-Araf Single GlcA residues are also present at the non-reducing termini of some short beta(1 -> 6)-galactan side chains In addition the beta-(1 -> 6)-galactan side chains are also substituted with beta-L-Arap We propose a polysaccharide structure of the wheat flour AGP that is substantially revised from earlier models (C) 2010 Elsevier Ltd All rights reserved
  ELSEVIER SCI LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2010.09.018
  DOI ID：10.1016/j.carres.2010.09.018, ISSN：0008-6215, PubMed ID：20971454, Web of Science ID：WOS:000285657700010
• Degradation of carbohydrate moieties of arabinogalactan-proteins by glycoside hydrolases from Neurospora crassa　　　　　　　　　　　　　　　
  Ryohei Takata; Keita Tokita; Satoko Mori; Ryohei Shimoda; Naoki Harada; Hitomi Ichinose; Satoshi Kaneko; Kiyohiko Igarashi; Masahiro Samejima; Yoichi Tsumuraya; Toshihisa Kotake
  Carbohydrate Research, 巻：345, 号：17, 開始ページ：2516, 終了ページ：2522, 2010年11月, ［査読有り］, ［最終著者, 責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2010.09.006
  DOI ID：10.1016/j.carres.2010.09.006, ISSN：0008-6215
• Chemoenzymatic Synthesis, Inhibition Studies, and X-ray Crystallographic Analysis of the Phosphono Analog of UDP-Galp as an Inhibitor and Mechanistic Probe for UDP-Galactopyranose Mutase　　　　　　　　　　　　　　　
  Sarathy Karunan Partha; Ali Sadeghi-Khomami; Kathryn Slowski; Toshihisa Kotake; Neil R. Thomas; David L. Jakeman; David A. R. Sanders
  Journal of Molecular Biology, 巻：403, 号：4, 開始ページ：578, 終了ページ：590, 2010年11月, ［査読有り］
  UDP (uridine diphosphate) galactopyranose mutase (UGM) is involved in the cell wall biosynthesis of many pathogenic microorganisms. UGM catalyzes the reversible conversion of UDP-alpha-D-galactopyranose into UDP-alpha-D-galactofuranose, with the latter being the precursor of galactofuranose (Galf) residues in cell walls. Glycoconjugates of Calf are essential components in the cell wall of various pathogenic bacteria, including Mycobacterium tuberculosis, the causative agent of tuberculosis. The absence of Calf in humans and its bacterial requirement make UGM a potential target for developing novel antibacterial agents. In this article, we report the synthesis, inhibitory activity, and X-ray crystallographic studies of UDP-phosphono-galactopyranose, a nonhydrolyzable C-glycosidic phosphonate. This is the first report on the synthesis of a phosphonate analog of UDP-alpha-D-galactopyranose by a chemoenzymatic phosphoryl coupling method. The phosphonate was evaluated against three bacterial UGMs and showed only moderate inhibition. We determined the crystal structure of the phosphonate analog bound to Deinococcus radiodurans UGM at 2.6 angstrom resolution. The phosphonate analog is bound in a novel conformation not observed in UGM substrate complex structures or in other enzyme sugar nucleotide phosphonate complexes. This complex structure provides a structural basis for the observed micromolar inhibition towards UGM. Steric clashes, loss of electrostatic stabilization between an active-site arginine (Arg305) and the phosphonate analog, and a 180 degrees flip of the hexose moiety account for the differences in the binding orientations of the isosteric phosphonate analog and the physiological substrate. This provides new insight into the ability of a sugar-nucleotide-binding enzyme to orient a substrate analog in an unexpected geometry and should be taken into consideration in designing such enzyme inhibitors. (C) 2010 Elsevier Ltd. All rights reserved.
  ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jmb.2010.08.053
  DOI ID：10.1016/j.jmb.2010.08.053, ISSN：0022-2836, PubMed ID：20850454, Web of Science ID：WOS:000284440500007
• Degradation of carbohydrate moieties of arabinogalactan-proteins by glycoside hydrolases from Neurospora crassa　　　　　　　　　　　　　　　
  Ryohei Takata; Keita Tokita; Satoko Mori; Ryohei Shimoda; Naoki Harada; Hitomi Ichinose; Satoshi Kaneko; Kiyohiko Igarashi; Masahiro Samejima; Yoichi Tsumuraya; Toshihisa Kotake
  Carbohydrate Research, 巻：345, 号：17, 開始ページ：2516, 終了ページ：2522, 2010年11月, ［査読有り］, ［最終著者, 責任著者］
  Arabinogalactan-proteins (AGPs) are a family of plant proteoglycans having large carbohydrate moieties attached to core-proteins. The carbohydrate moieties of AGPs commonly have beta-(1 -> 3)(1 -> 6)-galactan as the backbone, to which other auxiliary sugars such as L-Ara and GlcA are attached. For the present study, an a-L-arabinofuranosidase belonging to glycoside hydrolase family (GHF) 54, NcAraf1, and an endo-beta-(1 -> 6)-galactanase of GHF 5, Nc6GAL, were identified in Neurospora crassa. Recombinant NcAraf1 (rNcAraf1) expressed in Pichia pastoris hydrolyzed radish AGPs as well as arabinan and arabinoxylan. showing relatively broad substrate specificity toward polysaccharides containing a-L-arabinofuranosyl residues. Recombinant Nc6GAL (rNc6GAL) expressed in P. pastoris specifically acted on beta-(1 -> 6)-galactosyl residues. Whereas AGP from radish roots was hardly hydrolyzed by rNc6GAL alone, beta-(1 -> 6)-galactan side chains were reduced to one or two galactan residues by a combination of rNcAraf1 and rNc6GAL. These results suggest that the carbohydrate moieties of AGPs are degraded by the concerted action of NcAraf1 and Nc6GAL secreted from N. crassa. (C) 2010 Elsevier Ltd. All rights reserved.
  ELSEVIER SCI LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2010.09.006
  DOI ID：10.1016/j.carres.2010.09.006, ISSN：0008-6215, PubMed ID：20932514, Web of Science ID：WOS:000284520500013
• Rice BRITTLE CULM 3 (BC3) encodes a classical dynamin OsDRP2B essential for proper secondary cell wall synthesis　　　　　　　　　　　　　　　
  Ko Hirano; Toshihisa Kotake; Kumiko Kamihara; Kahori Tsuna; Tsutomu Aohara; Yasuko Kaneko; Hiroshi Takatsuji; Yoichi Tsumuraya; Shinji Kawasaki
  Planta, 巻：232, 号：1, 開始ページ：95, 終了ページ：108, 2010年06月, ［査読有り］
  "Brittle culm" mutants found in Gramineae crops are suitable materials to study the mechanism of secondary cell wall formation. Through positional cloning, we have identified a gene responsible for the brittle culm phenotype in rice, brittle culm 3 (bc3). BC3 encodes a member of the classical dynamin protein family, a family known to function widely in membrane dynamics. The bc3 mutation resulted in reductions of 28-36% in cellulose contents in culms, leaves, and roots, while other cell wall components remained unaffected. Reductions of cell wall thickness and birefringence were observed in both fiber (sclerenchyma) and parenchymal cells, together with blurring of the wall's layered structures. From promoter-GUS analyses, it was suggested that BC3 expression is directly correlated with active secondary cell wall synthesis. These results suggest that BC3 is tightly involved in the synthesis of cellulose and is essential for proper secondary cell wall construction.
  SPRINGER, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00425-010-1145-6
  DOI ID：10.1007/s00425-010-1145-6, ISSN：0032-0935, PubMed ID：20369251, Web of Science ID：WOS:000277792700008
• Generation of nucleotide sugars for biomass formation in plants　　　　　　　　　　　　　　　
  Toshihisa Kotake; Chie Hirosawa; Yasutoshi Ando; Yoichi Tsumuraya
  Plant Biotechnology, 巻：27, 号：3, 開始ページ：231, 終了ページ：236, 2010年, ［査読有り］, ［招待有り］, ［筆頭著者, 責任著者］
  Nucleotide sugars are activated forms of monosaccharides and serve as glycosyl donors for glycosyltransferases in the synthesis of cell wall polysaccharides. Since they affect the amounts and architecture of cell wall polysaccharides in plants, the levels of nucleotide sugars, as well as the levels of the glycosyltransferases, at least partially, regulate the production of plant cellulosic biomass. Nucleotide sugars are principally generated through de novo pathways, in which various UDP- and GDP-sugars are produced through sequential interconversions from starting substrates such as UDPglucose. The salvage pathway is an alternative route to synthesize nucleotide sugars. In the salvage pathway, free monosaccharides released during the metabolism of polysaccharides and glycoconjugates are first phosphorylated by monosaccharide kinases, and then converted to nucleotide sugars by nucleotide sugar pyrophosphorylases in the presence of the respective nucleotide triphosphates as co-substrates. In this review, we focus on the recent progress in our understanding of the mechanism for the generation of nucleotide sugars through the salvage pathway for free monosaccharides in higher plants.
  JAPANESE SOC PLANT CELL & MOLECULAR BIOL, 英語, 研究論文（学術雑誌）
  ISSN：1342-4580, Web of Science ID：WOS:000280085800003
• Sugar treatment inhibits IAA-induced expression of endo-1,3:1,4-beta-glucanase EI transcripts in barley coleoptile segments　　　　　　　　　　　　　　　
  Hiroyuki Takeda; Tomoko Sugahara; Toshihisa Kotake; Naoki Nakagawa; Naoki Sakurai
  Physiologia Plantarum, 巻：139, 号：4, 開始ページ：413, 終了ページ：420, 2010年, ［査読有り］
  The degradation of 1,3:1,4-beta-glucan by glucanases is believed to be critical for auxin-induced elongation in Gramineae coleoptile. In the present study, we reinvestigated the relationship between auxin-induced elongation and gene expression of glucanases upon treatment of coleoptile segments with sugars. Gene expression of exo-beta-1,3:1,4-glucanase ExoII was not affected by treatment with IAA and/or sucrose. In contrast, levels of endo-beta-1,3:1,4-glucanase EI transcripts increased in response to IAA treatment, which was negated by the addition of glucose or sucrose, although the addition of sucrose or glucose did not suppress IAA-induced elongation. Sugar composition analysis of the hemicellulosic fraction revealed that the addition of glucose suppressed the IAA-induced reduction of beta-glucan. In the coleoptile segments that were starved by pre-incubation in water, the IAA-induced accumulation of EI mRNA was accelerated, as compared with the non-starved segments, which suggests that the level of carbon source in the cytoplasm regulates EI expression. Moreover, in the basal region of coleoptiles, where IAA treatment does not induce elongation growth, high levels of EI transcripts were observed in the presence and absence of IAA treatment. These results strongly demonstrated that the expressions of exo- and endo-beta-glucanase genes are not directly involved in the IAA-induced loosening of cell walls associated with elongation and also suggests that cell walls may degrade 1,3:1,4-beta-glucan to provide glucose as an energy source for cell elongation.
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/j.1399-3054.2010.01372.x
  DOI ID：10.1111/j.1399-3054.2010.01372.x, ISSN：0031-9317, PubMed ID：20412461, Web of Science ID：WOS:000279840300007
• 1-Aminocyclopropane-1-carboxylic acid (ACC)-induced reorientation of cortical microtubules is accompanied by a transient increase in the transcript levels of gamma-tubulin complex and katanin genes in azuki bean epicotyls　　　　　　　　　　　　　　　
  Kouichi Soga; Aya Yamaguchi; Toshihisa Kotake; Kazuyuki Wakabayashi; Takayuki Hoson
  Journal of Plant Physiology, 巻：167, 号：14, 開始ページ：1165, 終了ページ：1171, 2010年, ［査読有り］
  The effects of 1-aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, on growth, orientation of cortical microtubules, and the transcript levels of gamma-tubulin complex (VaTUG and VaGCP3) and katanin (ValaN1)genes in azuki bean (Vigna angularis) epicotyls were examined. ACC inhibited elongation growth and stimulated lateral growth of epicotyls dose dependently. It also reduced the percentage of cells with transverse microtubules and increased the percentage of cells with longitudinal microtubules. A significant change in elongation and lateral growth was detected within 1 and 1.5h after the start of 10(-5)M ACC treatment, respectively. On the other hand, the reorientation of cortical microtubules from transverse to longitudinal direction began within 0.5 h, and continued until 2 h after the start of ACC treatment. ACC at 10(-5)M increased the transcript level of VaTUG, VaGCP3 and VaKTN1 within 0.5 h, and the levels of VaTUG and VaGCP3 became maximum at 1 h and that of VaKTN1 at 1.5 h, followed by a decrease to the control level. These results suggest that ACC transiently increases the transcript levels of gamma-tubulin complex and katanin genes, which may facilitate reorientation of cortical microtubules and modification of growth anisotropy from elongation to lateral growth in azuki bean epicotyls. (C) 2010 Elsevier GmbH. All rights reserved.
  ELSEVIER GMBH, URBAN & FISCHER VERLAG, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jplph.2010.04.001
  DOI ID：10.1016/j.jplph.2010.04.001, ISSN：0176-1617, PubMed ID：20451287, Web of Science ID：WOS:000281886500007
• Transient increase in the levels of γ-tubulin complex and katanin are responsible for reorientation by ethylene and hypergravity of cortical microtubules.　　　　　　　　　　　　　　　
  Soga K; Yamaguchi A; Kotake T; Wakabayashi K; Hoson T
  Plant Signaling and Behavior, 巻：5, 号：11, 開始ページ：1480, 終了ページ：1482, 2010年, ［査読有り］
  The body shape of a plant is primarily regulated by orientation of cortical microtubules. g-Tubulin complex and katanin are required for the nucleation and the severing of microtubules, respectively. Here we discuss the role of g-tubulin complex and katanin during reorientation of cortical microtubules. 1-Aminocyclopropane-1-carboxylic acid (ACC), the immediate precursor of ethylene, modifies growth anisotropy of azuki bean epicotyls
  it inhibits elongation growth and promotes lateral growth. The ACC-induced reorientation of cortical microtubules from transverse to longitudinal directions preceded the modification of growth anisotropy. The transcript level of g-tubulin complex (VaTUG and VaGCP3) and katanin (VaKTN1) was increased transiently by ACC treatment. During reorientation of cortical microtubules by hypergravity, which also modifies growth anisotropy of shoots, the expression levels of both g-tubulin complex and katanin genes were increased transiently. The increase in the number of the nucleated microtubule branch as well as the microtubulesevering activity via upregulation of g-tubulin complex and katanin genes may be involved in the reorientation of cortical microtubules, and contribute to the regulation of the shape of plant body. © 2010 Landes Bioscience.
  Landes Bioscience, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.4161/psb.5.11.13561
  DOI ID：10.4161/psb.5.11.13561, ISSN：1559-2324, PubMed ID：21051953, SCOPUS ID：85046916459
• Bifunctional cytosolic UDP-glucose 4-epimerases catalyse the interconversion between UDP-D-xylose and UDP-L-arabinose in plants　　　　　　　　　　　　　　　
  Kotake, Toshihisa; Takata, Ryohei; Verma, Rajeev; Takaba, Masato; Yamaguchi, Daisuke; Orita, Takahiro; Kaneko, Satoshi; Matsuoka, Koji; Koyama, Tetsuo; Reiter, Wolf-Dieter; Tsumuraya, Yoichi
  Biochemical Journal, 巻：424, 号：2, 開始ページ：169, 終了ページ：177, 2009年12月, ［査読有り］, ［筆頭著者, 責任著者］
  UDP-sugars serve as substrates in the synthesis of cell wall polysaccharides and are themselves generated through sequential interconversion reactions from UDP-Glc (UDP-glucose) as the starting substrate in the cytosol and the Golgi apparatus. For the present study, a soluble enzyme with UDP-Xyl (UDP-xylose) 4-epimerase activity was purified approx. 300-fold from pea (Pisum sativum L.) sprouts by conventional chromatography. The N-terminal amino acid sequence of the enzyme revealed that it is encoded by a predicted UDP-Glc 4-epimerase gene, PsUGE1, and is distinct from the UDP-Xyl 4-epimerase localized in the Golgi apparatus. rPsUGE1 (recombinant P. sativum UGE1) expressed in Escherichia coli exhibited both UDP-Xyl 4-epimerase and UDP-Glc 4-epimerase activities with apparent Km values of 0.31, 0.29, 0.16 and 0.15 mM for UDP-Glc, UDP-Gal (UDP-galactose), UDP-Ara (UDP-L-arabinose) and UDP-Xyl respectively. The apparent equilibrium constant for UDP-Ara formation from UDP-Xyl was 0.89, whereas that for UDP-Gal formation from UDP-Glc was 0.24. Phylogenetic analysis revealed that PsUGE1 forms a group with Arabidopsis UDP-Glc 4-epimerases, AtUGE1 and AtUGE3, apart from a group including AtUGE2, AtUGE4 and AtUGE5. Similar to rPsUGE1, recombinant AtUGE1 and AtUGE3 expressed in E. coli showed high UDP-Xyl 4-epimerase activity in addition to their UDP-Glc 4-epimerase activity. Our results suggest that PsUGE1 and its close homologues catalyse the interconversion between UDP-Xyl and UDP-Ara as the last step in the cytosolic de novo pathway for UDP-Ara generation. Alternatively, the net flux of metabolites may be from UDP-Ara to UDP-Xyl as part of the salvage pathway for Ara.
  Portland Press Ltd., 研究論文（学術雑誌）
  DOI：https://doi.org/10.1042/BJ20091025
  DOI ID：10.1042/BJ20091025, ISSN：0264-6021, eISSN：1470-8728, ORCID：20757452, Web of Science ID：WOS:000272135100002
• Gummosis in grape hyacinth (Muscari armeniacum) bulbs: hormonal regulation and chemical composition of gums
  Kensuke Miyamoto; Toshihisa Kotake; Makiko Sasamoto; Marian Saniewski; Junichi Ueda
  Journal of Plant Research, 巻：123, 号：3, 開始ページ：363, 終了ページ：370, 2009年11月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10265-009-0273-1
  DOI ID：10.1007/s10265-009-0273-1, ISSN：0918-9440, eISSN：1618-0860
• Rice BRITTLE CULM 5 (BRITTLE NODE) is Involved in Secondary Cell Wall Formation in the Sclerenchyma Tissue of Nodes
  Tsutomu Aohara; Toshihisa Kotake; Yasuko Kaneko; Hiroshi Takatsuji; Yoichi Tsumuraya; Shinji Kawasaki
  Plant and Cell Physiology, 巻：50, 号：11, 開始ページ：1886, 終了ページ：1897, 2009年11月, ［査読有り］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcp133
  DOI ID：10.1093/pcp/pcp133, ISSN：0032-0781, eISSN：1471-9053
• The GLABRA2 homeodomain protein directly regulates CESA5 and XTH17 gene expression in Arabidopsis roots
  Rumi Tominaga‐Wada; Mineko Iwata; Junji Sugiyama; Toshihisa Kotake; Tetsuya Ishida; Ryusuke Yokoyama; Kazuhiko Nishitani; Kiyotaka Okada; Takuji Wada
  The Plant Journal, 巻：60, 号：3, 開始ページ：564, 終了ページ：574, 2009年10月, ［査読有り］
  Summary
  
  Arabidopsis root hair formation is determined by the patterning genes CAPRICE (CPC), GLABRA3 (GL3), WEREWOLF (WER) and GLABRA2 (GL2), but little is known about the later changes in cell wall material during root hair formation. A combined Fourier‐transform infrared microspectroscopy–principal components analysis (FTIR‐PCA) method was used to detect subtle differences in the cell wall material between wild‐type and root hair mutants in Arabidopsis. Among several root hair mutants, only the gl2 mutation affected root cell wall polysaccharides. Five of the 10 genes encoding cellulose synthase (CESA1–10) and 4 of 33 xyloglucan endotransglucosylase (XTH1–33) genes in Arabidopsis are expressed in the root, but only CESA5 and XTH17 were affected by the gl2 mutation. The L1‐box sequence located in the promoter region of these genes was recognized by the GL2 protein. These results indicate that GL2 directly regulates cell wall‐related gene expression during root development.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/j.1365-313x.2009.03976.x
  DOI ID：10.1111/j.1365-313x.2009.03976.x, ISSN：0960-7412, eISSN：1365-313X
• Molecular Cloning and Expression inPichia pastorisof aIrpex lacteusExo-β-(1→3)-galactanase Gene
  Toshihisa KOTAKE; Kiminari KITAZAWA; Ryohei TAKATA; Kohei OKABE; Hitomi ICHINOSE; Satoshi KANEKO; Yoichi TSUMURAYA
  Bioscience, Biotechnology, and Biochemistry, 巻：73, 号：10, 開始ページ：2303, 終了ページ：2309, 2009年10月, ［査読有り］, ［筆頭著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1271/bbb.90433
  DOI ID：10.1271/bbb.90433, ISSN：0916-8451, eISSN：1347-6947
• The Transcript Level of Katanin Gene is Increased Transiently in Response to Changes in Gravitational Conditions in Azuki Bean Epicotyls　　　　　　　　　　　　　　　
  Soga Kouichi; Kotake Toshihisa; Wakabayashi Kazuyuki; Kamisaka Seiichiro; Hoson Takayuki
  Biological Sciences in Space, 巻：23, 号：1, 開始ページ：23, 終了ページ：28, 2009年, ［査読有り］
  英語
  DOI：https://doi.org/10.2187/bss.23.23
  DOI ID：10.2187/bss.23.23, ISSN：0914-9201, CiNii Articles ID：120006369774, CiNii Books ID：AN10164806
• Arabinogalactan-proteins in the evolution of gravity resistance in land plants　　　　　　　　　　　　　　　
  Kotake T; Kitazawa K; Hirata N; Soga K; Tsumuraya Y
  Biological Sciences in Space, 巻：23, 号：3, 開始ページ：143, 終了ページ：149, 2009年, ［査読有り］, ［招待有り］
  DOI：https://doi.org/10.2187/bss.23.143
  DOI ID：10.2187/bss.23.143
• beta-1,3 : 1,4-glucan synthase activity in rice seedlings under water　　　　　　　　　　　　　　　
  Kimpara, Tomoya; Aohara, Tsutomu; Soga, Kouichi; Wakabayashi; Kazuyuki; Hoson, Takayuki; Tsumuraya, Yoichi; Kotake, Toshihisa
  Annals of Botany, 巻：102, 号：2, 開始ページ：221, 終了ページ：226, 2008年08月, ［査読有り］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/aob/mcn077
  DOI ID：10.1093/aob/mcn077, ISSN：0305-7364, ORCID：20757425, PubMed ID：18487614, Web of Science ID：WOS:000257786300007
• Transient increase in the transcript levels of γ-tubulin complex genes during reorientation of cortical microtubules by gravity in azuki bean (Vigna angularis) epicotyls
  Kouichi Soga; Toshihisa Kotake; Kazuyuki Wakabayashi; Seiichiro Kamisaka; Takayuki Hoson
  Journal of Plant Research, 巻：121, 号：5, 開始ページ：493, 終了ページ：498, 2008年07月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s10265-008-0179-3
  DOI ID：10.1007/s10265-008-0179-3, ISSN：0918-9440, eISSN：1618-0860
• Properties of family 79 β-glucuronidases that hydrolyze β-glucuronosyl and 4-O-methyl-β-glucuronosyl residues of arabinogalactan-protein　　　　　　　　　　　　　　　
  Tomoyuki Konishi; Toshihisa Kotake; Dina Soraya; Koji Matsuoka; Tetsuo Koyama; Satoshi Kaneko; Kiyohiko Igarashi; Masahiro Samejima; Yoichi Tsumuraya
  Carbohydrate Research, 巻：343, 号：7, 開始ページ：1191, 終了ページ：1201, 2008年05月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.carres.2008.03.004
  DOI ID：10.1016/j.carres.2008.03.004, ISSN：0008-6215
• Characterization of an Endo-β-1,6-Galactanase from Streptomyces avermitilis NBRC14893
  Hitomi Ichinose; Toshihisa Kotake; Yoichi Tsumuraya; Satoshi Kaneko
  Applied and Environmental Microbiology, 巻：74, 号：8, 開始ページ：2379, 終了ページ：2383, 2008年04月, ［査読有り］
  ABSTRACT
  
  The putative endo-β-1,6-galactanase gene from Streptomyces avermitilis was cloned and expressed in Escherichia coli , and the enzymatic properties of the recombinant enzyme were characterized. The gene consisted of a 1,476-bp open reading frame and encoded a 491-amino-acid protein, comprising an N-terminal secretion signal sequence and glycoside hydrolase family 5 catalytic module. The recombinant enzyme, Sa1,6Gal5A, catalyzed the hydrolysis of β-1,6-linked galactosyl linkages of oligosaccharides and polysaccharides. The enzyme produced galactose and a range of β-1,6-linked galacto-oligosaccharides, predominantly β-1,6-galactobiose, from β-1,6-galactan chains. There was a synergistic effect between the enzyme and Sa1,3Gal43A in degrading tomato arabinogalactan proteins. These results suggest that Sa1,6Gal5A is the first identified endo-β-1,6-galactanase from a prokaryote.
  American Society for Microbiology, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1128/aem.01733-07
  DOI ID：10.1128/aem.01733-07, ISSN：0099-2240, eISSN：1098-5336
• A bifunctional enzyme with L-fucokinase and GDP-L-fucose pyrophosphorylase activities salvages free L-fucose in Arabidopsis　　　　　　　　　　　　　　　
  Kotake, Toshihisa; Hojo, Sachiko; Tajima, Noriaki; Matsuoka, Koji; Koyama, Tetsuo; Tsumuraya, Yoichi
  Journal of Biological Chemistry, 巻：283, 号：13, 開始ページ：8125, 終了ページ：8135, 2008年03月, ［査読有り］, ［筆頭著者, 責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.M710078200
  DOI ID：10.1074/jbc.M710078200, ISSN：0021-9258, ORCID：20757424, Web of Science ID：WOS:000254288000009
• Properties and Physiological Functions of UDP-Sugar Pyrophosphorylase inArabidopsis
  Toshihisa KOTAKE; Sachiko HOJO; Daisuke YAMAGUCHI; Tsutomu AOHARA; Tomoyuki KONISHI; Yoichi TSUMURAYA
  Bioscience, Biotechnology, and Biochemistry, 巻：71, 号：3, 開始ページ：761, 終了ページ：771, 2007年03月, ［査読有り］, ［筆頭著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1271/bbb.60605
  DOI ID：10.1271/bbb.60605, ISSN：0916-8451, eISSN：1347-6947
• Chain elongation of pectic β-(1→4)-galactan by a partially purified galactosyltransferase from soybean (Glycine max Merr.) hypocotyls
  Tomoyuki Konishi; Toshihisa Kotake; Yoichi Tsumuraya
  Planta, 巻：226, 号：3, 開始ページ：571, 終了ページ：579, 2007年03月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00425-007-0505-3
  DOI ID：10.1007/s00425-007-0505-3, ISSN：0032-0935, eISSN：1432-2048
• Degradation of the carbohydrate moieties of arabinogalactan-proteins by microbial beta-glucunonidases　　　　　　　　　　　　　　　
  Konishi Tomoyuki; Kotake Toshihisa; Soraya Dina; Kaneko Satoshi; Igarashi Kiyohiko; Samejima Masahiro; Tsumuraya Yoichi
  PLANT AND CELL PHYSIOLOGY, 巻：48, 開始ページ：S80, 2007年, ［査読有り］
  DOI：https://doi.org/10.14841/jspp.2007.0.255.0
  DOI ID：10.14841/jspp.2007.0.255.0, ISSN：0032-0781, Web of Science ID：WOS:000245922700316
• Characterization of an Exo-β-1,3-D-galactanase fromStreptomyces avermitilisNBRC14893 Acting on Arabinogalactan-Proteins
  Hitomi ICHINOSE; Toshihisa KOTAKE; Yoichi TSUMURAYA; Satoshi KANEKO
  Bioscience, Biotechnology, and Biochemistry, 巻：70, 号：11, 開始ページ：2745, 終了ページ：2750, 2006年11月, ［査読有り］
  Informa UK Limited, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1271/bbb.60365
  DOI ID：10.1271/bbb.60365, ISSN：0916-8451, eISSN：1347-6947
• An alpha-L-arabinofuranosidase/beta-D-xylosidase from immature seeds of radish (Raphanus sativus L.)
  Kotake T, Tsuchiya K, Aohara T, Konishi T, Kaneko S, Igarashi K, Samejima M, Tsumuraya Y.
  Journal of Experimental Botany, 巻：57, 号：10, 開始ページ：2353, 終了ページ：2362, 2006年05月, ［査読有り］, ［筆頭著者, 責任著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/jxb/erj206
  DOI ID：10.1093/jxb/erj206, ISSN：0022-0957, eISSN：1460-2431
• Characterization of an Exo-β-1,3-Galactanase from Clostridium thermocellum
  Hitomi Ichinose; Atsushi Kuno; Toshihisa Kotake; Makoto Yoshida; Kazuo Sakka; Jun Hirabayashi; Yoichi Tsumuraya; Satoshi Kaneko
  Applied and Environmental Microbiology, 巻：72, 号：5, 開始ページ：3515, 終了ページ：3523, 2006年05月, ［査読有り］
  ABSTRACT
  
  A gene encoding an exo-β-1,3-galactanase from Clostridium thermocellum , Ct1,3Gal43A, was isolated. The sequence has similarity with an exo-β-1,3-galactanase of Phanerochaete chrysosporium (Pc1,3Gal43A). The gene encodes a modular protein consisting of an N-terminal glycoside hydrolase family 43 (GH43) module, a family 13 carbohydrate-binding module (CBM13), and a C-terminal dockerin domain. The gene corresponding to the GH43 module was expressed in Escherichia coli , and the gene product was characterized. The recombinant enzyme shows optimal activity at pH 6.0 and 50°C and catalyzes hydrolysis only of β-1,3-linked galactosyl oligosaccharides and polysaccharides. High-performance liquid chromatography analysis of the hydrolysis products demonstrated that the enzyme produces galactose from β-1,3-galactan in an exo-acting manner. When the enzyme acted on arabinogalactan proteins (AGPs), the enzyme produced oligosaccharides together with galactose, suggesting that the enzyme is able to accommodate a β-1,6-linked galactosyl side chain. The substrate specificity of the enzyme is very similar to that of Pc1,3Gal43A, suggesting that the enzyme is an exo-β-1,3-galactanase. Affinity gel electrophoresis of the C-terminal CBM13 did not show any affinity for polysaccharides, including β-1,3-galactan. However, frontal affinity chromatography for the CBM13 indicated that the CBM13 specifically interacts with oligosaccharides containing a β-1,3-galactobiose, β-1,4-galactosyl glucose, or β-1,4-galactosyl N -acetylglucosaminide moiety at the nonreducing end. Interestingly, CBM13 in the C terminus of Ct1,3Gal43A appeared to interfere with the enzyme activity toward β-1,3-galactan and α- l -arabinofuranosidase-treated AGP.
  American Society for Microbiology, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1128/aem.72.5.3515-3523.2006
  DOI ID：10.1128/aem.72.5.3515-3523.2006, ISSN：0099-2240, eISSN：1098-5336
• An exo-beta-1,3-galactanase having a novel beta-1,3-galactan-binding module from Phanerochaete chrysosporium　　　　　　　　　　　　　　　
  Ichinose, H.; Yoshida, M.; Kotake, T.; Kuno, A.; Igarashi, K.; Tsumuraya, Y.; Samejima, M.; Hirabayashi, J.; Kobayashi, H.; Kaneko, S.
  Journal of Biological Chemistry, 巻：280, 号：27, 開始ページ：25820, 終了ページ：25829, 2005年07月, ［査読有り］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.M501024200
  DOI ID：10.1074/jbc.M501024200, ISSN：0021-9258, ORCID：20757435, Web of Science ID：WOS:000230207900063
• Molecular Cloning of a β-Galactosidase from Radish That Specifically Hydrolyzes β-(1→3)- and β-(1→6)-Galactosyl Residues of Arabinogalactan Protein
  Toshihisa Kotake; Soraya Dina; Tomoyuki Konishi; Satoshi Kaneko; Kiyohiko Igarashi; Masahiro Samejima; Yoko Watanabe; Kazumasa Kimura; Yoichi Tsumuraya
  Plant Physiology, 巻：138, 号：3, 開始ページ：1563, 終了ページ：1576, 2005年07月, ［査読有り］, ［筆頭著者, 責任著者］
  
  A basic β-galactosidase with high specificity toward β-(1→3)- and β-(1→6)-galactosyl residues was cloned from radish (Raphanus sativus) plants by reverse transcription-PCR. The gene, designated RsBGAL1, contained an open reading frame consisting of 2,532 bp (851 amino acids). It is expressed in hypocotyls and young leaves. RsBGAL1 was highly similar to β-galactosidases having exo-β-(1→4)-galactanase activity found in higher plants and belongs to family 35 of the glycosyl hydrolases. Recombinant RsBGAL1 was expressed in Pichia pastoris and purified to homogeneity. The recombinant enzyme specifically hydrolyzed β-(1→3)- and β-(1→6)-galactooligosaccharides, the same substrates as the native enzyme isolated from radish seeds (Sekimata et al., 1989). It split off about 90% of the carbohydrate moieties of an arabinogalactan protein extracted from radish roots in concerted action with microbial α-l-arabinofuranosidase and β-glucuronidase. These results suggest that RsBGAL1 is a new kind of β-galactosidase with different substrate specificity than other β-galactosidases that exhibit exo-β-(1→4)-galactanase activity. The C-terminal region (9.6 kD) of RsBGAL1 is significantly similar to the Gal lectin-like domain, but this region is not retained in the native enzyme. Assuming posttranslational processing of RsBGAL1 with elimination of the Gal lectin-like domain results in a protein consisting of two subunits with molecular masses of 46 and 34 kD (calculated from the RsBGAL1 gene sequence). This is in good agreement with the SDS-PAGE and matrix-assisted laser desorption/ionization-time-of flight mass spectrometry measurements for subunits of the native enzyme (45 and 34 kD) and may thus partially explain the formation process of the native enzyme.
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.105.062562
  DOI ID：10.1104/pp.105.062562, ISSN：0032-0889, eISSN：1532-2548
• Mode of Action of β-Glucuronidase fromAspergillus nigeron the Sugar Chains of Arabinogalactan-Protein
  Md. Ashraful HAQUE; Toshihisa KOTAKE; Yoichi TSUMURAYA
  Bioscience, Biotechnology, and Biochemistry, 巻：69, 号：11, 開始ページ：2170, 終了ページ：2177, 2005年01月, ［査読有り］
  Informa UK Limited, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1271/bbb.69.2170
  DOI ID：10.1271/bbb.69.2170, ISSN：0916-8451, eISSN：1347-6947
• Biosynthesis of (1 -> 3),(1 -> 4)-beta-glucan in developing endosperms of barley (Hordeum vulgare)　　　　　　　　　　　　　　　
  Tsuchiya, K.; Urahara, T.; Konishi, T.; Kotake, T.; Tohno-oka, T.; Komae, K.; Kawada, N.; Tsumuraya, Y.
  Physiologia Plantarum, 巻：125, 号：2, 開始ページ：181, 終了ページ：191, 2005年, ［査読有り］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/j.1399-3054.2005.00558.x
  DOI ID：10.1111/j.1399-3054.2005.00558.x, ORCID：20757436, Web of Science ID：WOS:000231677000004
• UDP-sugar pyrophosphorylase with broad substrate specificity toward various monosaccharide 1-phosphates from pea sprouts　　　　　　　　　　　　　　　
  Kotake, T.; Yamaguchi, D.; Ohzono, H.; Hojo, S.; Kaneko, S.; Ishida, HK; Tsumuraya, Y.
  Journal of Biological Chemistry, 巻：279, 号：44, 開始ページ：45728, 終了ページ：45736, 2004年10月, ［査読有り］, ［筆頭著者, 責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1074/jbc.M408716200
  DOI ID：10.1074/jbc.M408716200, ISSN：0021-9258, ORCID：20757443, Web of Science ID：WOS:000224694900055
• Biosynthesis of pectic galactan by membrane-bound galactosyltransferase from soybean ( Glycine max Merr.) seedlings
  Tomoyuki Konishi; Terukazu Mitome; Hiroyuki Hatsushika; Md. Ashraful Haque; Toshihisa Kotake; Yoichi Tsumuraya
  Planta, 巻：218, 号：5, 開始ページ：833, 終了ページ：842, 2004年03月, ［査読有り］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s00425-003-1163-8
  DOI ID：10.1007/s00425-003-1163-8, ISSN：0032-0935, eISSN：1432-2048
• Molecular cloning and expression in Escherichia coli of a Trichoderma viride endo-beta-(1 6)-galactanase gene
  Toshihisa KOTAKE; Satoshi KANEKO; Aya KUBOMOTO; Md. Ashraful HAQUE; Hideyuki KOBAYASHI; Yoichi TSUMURAYA
  Biochemical Journal, 巻：377, 号：3, 開始ページ：749, 終了ページ：755, 2004年02月, ［査読有り］, ［筆頭著者, 責任著者］
  A gene encoding endo-β-(1→6)-galactanase from Trichoderma viride was cloned by reverse transcriptase–PCR and expressed in Escherichia coli. The gene contained an open reading frame consisting of 1437 bp (479 amino acids). The deduced amino acid sequence of the protein showed little similarity with other known glycoside hydrolases. A signal sequence (20 amino acids) was found at the N-terminal region of the protein and the molecular mass of the mature form was calculated to be 50.488 kDa. The gene product expressed in E. coli as a recombinant protein fused with thioredoxin and His6 tags had almost the same substrate specificity and mode of action as native enzyme purified from a commercial cellulase preparation of T. viride, i.e. recombinant enzyme endo-hydrolysed β-(1→6)-galacto-oligomers with a DP (degree of polymerization) higher than 3, and it could also hydrolyse α-l-arabinofuranosidase-treated arabinogalactan protein from radish. It produced β-(1→6)-galacto-oligomers ranging from DP 2 to at least 8 at the initial hydrolysis stage and galactose and β-(1→6)-galactobiose as the major products at the final reaction stage. These results indicate that the cloned gene encodes an endo-β-(1→6)-galactanase. As far as we know, this is the first time an endo-β-(1→6)-galactanase has been cloned.
  Portland Press Ltd., 研究論文（学術雑誌）
  DOI：https://doi.org/10.1042/bj20031145
  DOI ID：10.1042/bj20031145, ISSN：0264-6021, eISSN：1470-8728
• A b-(14)-xylosyltransferase involved in the synthesis of arabinoxylans in developing barley endosperms　　　　　　　　　　　　　　　
  Urahara, T.; Tsuchiya, K.; Kotake, T.; Tohno-oka, T.; Komae, K.; Kawada, N.; Tsumuraya, Y.
  Physiologia Plantarum, 巻：122, 号：2, 開始ページ：169, 終了ページ：180, 2004年, ［査読有り］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1111/j.0031-9317.2004.00390.x
  DOI ID：10.1111/j.0031-9317.2004.00390.x, ORCID：20757440, Web of Science ID：WOS:000224068300002
• Arabidopsis TERMINAL FLOWER 2 Gene Encodes a Heterochromatin Protein 1 Homolog and Represses both FLOWERING LOCUS T to Regulate Flowering Time and Several Floral Homeotic Genes
  Toshihisa Kotake; Shinobu Takada; Kenji Nakahigashi; Masaaki Ohto; Koji Goto
  Plant and Cell Physiology, 巻：44, 号：6, 開始ページ：555, 終了ページ：564, 2003年06月, ［査読有り］, ［筆頭著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcg091
  DOI ID：10.1093/pcp/pcg091, ISSN：0032-0781, eISSN：1471-9053
• Expression and Function of Cell Wall-Bound Cationic Peroxidase in Asparagus Somatic Embryogenesis
  Hiroyuki Takeda; Toshihisa Kotake; Naoki Nakagawa; Naoki Sakurai; Donald J. Nevins
  Plant Physiology, 巻：131, 号：4, 開始ページ：1765, 終了ページ：1774, 2003年04月, ［査読有り］
  Abstract
  
  Cultured asparagus (Asparagus officinalis L. cv Y6) cells induced to regenerate into whole plants through somatic embryogenesis secreted a 38-kD protein into cell walls. The full-length cDNA sequence of this protein (Asparagus officinalisperoxidase 1 [AoPOX1]) determined by reverse transcriptase-polymerase chain reaction showed similarity with plant peroxidases.AoPOX1 transcripts were particularly abundant during early somatic embryogenesis. To evaluate the in vivo function of AoPOX1 protein, purified recombinant AoPOX1 protein was reacted with a series of phenolic substrates. The AoPOX1 protein was effective in the metabolism of feruloyl (o-methoxyphenol)-substituted substrates, including coniferyl alcohol. The reaction product of coniferyl alcohol was fractionated and subjected to gas chromatography-mass spectrometry analysis and 1H-nuclear magnetic resonance analysis, indicating that the oxidation product of coniferyl alcohol in the presence of AoPOX1 was dehydrodiconiferyl alcohol. The concentration of dehydrodiconiferyl alcohol in the cultured medium of the somatic embryos was in the range of 10−8  m. Functions of the AoPOX1 protein in the cell differentiation are discussed.
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1104/pp.102.014654
  DOI ID：10.1104/pp.102.014654, ISSN：0032-0889, eISSN：1532-2548
• Small complex‐type N‐linked glycans are attached to cell‐wall bound exo‐β‐glucanases of both mung bean and barley seedlings
  Toshihisa Kotake; Akiko Tonari; Masaya Ohta; Fumito Matsuura; Naoki Sakurai
  Physiologia Plantarum, 巻：112, 号：3, 開始ページ：308, 終了ページ：314, 2001年07月, ［査読有り］, ［筆頭著者］
  N‐linked glycans of wall‐bound exo‐β‐glucanases from mung bean and barley seedlings, namely Mung‐ExoI and Barley‐ExoII, were characterized. The N‐linked glycans of Mung‐ExoI and Barley‐ExoII were liberated by gas‐phase hydrazinolysis followed by re‐N‐acetylation. Their structures were determined by two‐dimensional sugar‐mapping analysis and MALDI‐TOF mass spectrometry. N‐glycans from both glucanases were of paucimannosidic‐type (small complex‐type) structures, Manα1‐6(±Manα1‐3)(Xylβ1‐2)Manβ1‐4GlcNAcβ1‐4(±Fucα1‐3) GlcNAc, which are known as typical vacuole‐type N‐glycans. The results suggest that N‐glycans of cell‐wall glucanase were produced by partial trimming of complex‐type N‐glycans by exoglycosidases during its transport from Golgi apparatus to cell walls or in the cell walls.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1034/j.1399-3054.2001.1120302.x
  DOI ID：10.1034/j.1399-3054.2001.1120302.x, ISSN：0031-9317, eISSN：1399-3054
• Role of wall-bound beta-glucanases in regulating tip-growth of Lilium longiflorum pollen tubes　　　　　　　　　　　　　　　
  Li, YQ; Kotake, T.; Sakurai, N.; Zhao, NM; Liu, Q.
  Acta Botanica Sinica, 巻：43, 号：5, 開始ページ：461, 終了ページ：468, 2001年, ［査読有り］
  英語, 研究論文（学術雑誌）
  ORCID：20757407, Web of Science ID：WOS:000169092100002
• Auxin-induced elongation growth and expressions of cell wall-bound exo- and endo-beta-glucanases in barley coleoptiles　　　　　　　　　　　　　　　
  Kotake, T.; Nakagawa, N.; Takeda, K.; Sakurai, N.
  Plant and Cell Physiology, 巻：41, 号：11, 開始ページ：1272, 終了ページ：1278, 2000年11月, ［査読有り］, ［筆頭著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/pcp/pcd056
  DOI ID：10.1093/pcp/pcd056, ISSN：0032-0781, eISSN：1471-9053, ORCID：20757409, Web of Science ID：WOS:000165474200013
• Characterization and function of wall-bound exo-β-glucanases of Lilium longiflorum pollen tubes
  Toshihisa Kotake; YiQin. Li; Mai Takahashi; Naoki. Sakurai
  Sexual Plant Reproduction, 巻：13, 号：1, 開始ページ：1, 終了ページ：9, 2000年07月, ［査読有り］, ［筆頭著者］
  Springer Science and Business Media LLC, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1007/s004970000036
  DOI ID：10.1007/s004970000036, ISSN：0934-0882
• Purification and characterization of wall-bound exo-1,3-β-D-glucanase from barley (Hordeum vulgare L.) seedlings
  Kotake, T.; Nakagawa, N.; Takeda, K.; Sakurai, N.
  Plant and Cell Physiology, 巻：38, 号：2, 開始ページ：194, 終了ページ：200, 1997年01月, ［査読有り］, ［筆頭著者］
  Oxford University Press (OUP), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1093/oxfordjournals.pcp.a029152
  DOI ID：10.1093/oxfordjournals.pcp.a029152, ISSN：0032-0781, eISSN：1471-9053, ORCID：63916535, SCOPUS ID：0031080526

• シロイヌナズナ子葉敷石細胞の多方向への平面成長は団扇型の子葉形態形成に寄与する　　　　　　　　　　　　　　　
  菊川琴美; 今村寿子; 曽我康一; 小竹敬久; 檜垣匠
  日本植物生理学会年会(Web), 巻：64th, 2023年
  J-Global ID：202302263140715376
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  宮城敦子; 宮城敦子; 森和久; 石川寿樹; 大久保智司; 安達俊輔; 大川泰一郎; 山口雅利; 小竹敬久; 川合真紀
  日本植物生理学会年会(Web), 巻：64th, 2023年
  J-Global ID：202302234679567567
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  菊川琴美; 曽我康一; 今村寿子; 小竹敬久; 檜垣匠
  日本植物学会大会研究発表記録(CD-ROM), 巻：86th, 2022年
  J-Global ID：202302270083809125
• 微小管結合タンパク質RIC1過剰発現株の解析から探る葉のスムーズな形態形成　　　　　　　　　　　　　　　
  菊川琴美; 曽我康一; 今村寿子; 小竹敬久; 檜垣匠
  バイオイメージング, 巻：31, 号：2, 2022年
  ISSN：1342-2634, J-Global ID：202202269025007659
• 微小管結合タンパク質RIC1過剰発現による子葉器官および表皮細胞の形態変化　　　　　　　　　　　　　　　
  菊川琴美; 曽我康一; 今村寿子; 小竹敬久; 檜垣匠
  日本植物生理学会年会(Web), 巻：63rd, 2022年
  J-Global ID：202202263500470129
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  日本植物学会大会研究発表記録(CD-ROM), 巻：85th, 2021年
  J-Global ID：202302210880983493
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  西垣南歩; 吉見圭永; 國枝正; 高橋大輔; 円谷陽一; 小竹敬久
  日本植物学会大会研究発表記録(CD-ROM), 巻：84th, 2020年
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  吉條美由; 近藤辰哉; 中屋愼; 中屋愼; 竹中重雄; 小竹敬久; 中澤昌美; 上田光宏; 阪本龍司
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  ISSN：2186-7976, J-Global ID：202002272321338543
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  松山佳織; 岸根尚美; 藤本瑞; 砂川直輝; 小竹敬久; 円谷陽一; 鮫島正浩; 鮫島正浩; 五十嵐圭日子; 金子哲
  応用糖質科学, 巻：10, 号：4, 2020年
  ISSN：2185-6427, J-Global ID：202102235409737243
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  日本植物生理学会年会(Web), 巻：60th, 2019年
  J-Global ID：201902225062471345
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  曽我康一; 山崎千秋; 鎌田源司; 谷川直樹; 笠原春夫; 矢野幸子; 湖城恵; 朽名夏麿; 朽名夏麿; 加藤壮英; 橋本隆; 小竹敬久; 若林和幸; 保尊隆享
  日本植物学会大会研究発表記録, 巻：81st, 開始ページ：215, 2017年09月01日
  日本語
  J-Global ID：201702213496858490
• シロイヌナズナの胚軸の抗重力反応におけるMAP65-1およびBPP1の役割　　　　　　　　　　　　　　　
  Murakami Mana; Soga Kouichi; Kotake Toshihisa; Kato Takehide; Hashimoto Takashi; Wakabayashi Kazuyuki; Hoson Takayuki
  Biological Sciences in Space (Web), 巻：30, 2016年
  ISSN：1349-967X, J-Global ID：201702259463475836
• 産学官連携による地域農・畜・水産物活用のための機能性食品開発研究を追う(42)埼玉大麦プロジェクトの進展　　　　　　　　　　　　　　　
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  食品と開発, 巻：51, 号：1, 開始ページ：66, 終了ページ：69, 2016年01月
  UBMメディア, 日本語
  ISSN：0911-3932, CiNii Articles ID：40020705213, CiNii Books ID：AN10051049
• 埼玉大麦プロジェクトの進展　　　　　　　　　　　　　　　
  円谷陽一; 小竹敬久; 川嶋かほる; 大久保俊彦; 東海林義和
  食品と開発, 巻：51, 開始ページ：66, 終了ページ：69, 2016年
  日本語
• 真菌由来AGP糖鎖分解酵素を導入したシロイヌナズナの形質　　　　　　　　　　　　　　　
  吉見圭永; 吉村真美; 八鍬頼誠; 芝野誠二; 出崎能丈; 澁谷直人; 円谷陽一; 小竹敬久
  日本植物学会大会研究発表記録, 巻：79th, 2015年
  J-Global ID：201502216160625700
• Da-7 Bifidobacterium longum由来のβ-1,6-ガラクタン側鎖分解酵素群の機能解析(ヘミセルラーゼ,一般講演,日本応用糖質科学会平成26年度大会(第63回))　　　　　　　　　　　　　　　
  坂本 彩美; 下川 倫子; 小竹 敬久; 円谷 陽一; 北原 兼文; 藤田 清貴
  応用糖質科学 : 日本応用糖質科学会誌, 巻：4, 号：3, 開始ページ：B54, 2014年08月20日
  日本応用糖質科学会, 日本語
  ISSN：2185-6427, CiNii Articles ID：110009843642, CiNii Books ID：AA12509099
• エノキタケ由来AGPコアタンパク質分解酵素の精製　　　　　　　　　　　　　　　
  吉見圭永; 菅原優美; 金子哲; 五十嵐圭日子; 小竹敬久; 円谷陽一
  日本植物生理学会年会要旨集, 巻：55th, 2014年
  J-Global ID：201402255283240550
• アラビノガラクタン-プロテインのコアタンパク質に作用するプロテアーゼの精製　　　　　　　　　　　　　　　
  吉見圭永; 菅原優美; 堀千明; 五十嵐圭日子; 堂前直; 堂前直; 金子哲; 小竹敬久; 円谷陽一
  日本植物学会大会研究発表記録, 巻：78th, 2014年
  J-Global ID：201402279306931977
• 宇宙の微小重力環境で生育したイネ芽生えにおける細胞壁フェノール化合物形成
  若林和幸; 曽我康一; 保尊隆享; 小竹敬久; 山崎丘; 東端晃; 石岡憲昭; 嶋津徹; 福井啓二; 長田郁子; 笠原春夫; 鎌田源司
  日本植物学会大会研究発表記録, 巻：77th, 開始ページ：203, 2013年08月20日
  日本語
  J-Global ID：201302208474286228
• 消費者受容性の高い「機能性大麦食品」の開発と普及活動　　　　　　　　　　　　　　　
  円谷 陽一; 小竹 敬久; 川嶋 かほる; 東海林 義和
  ＪＡＴＡＦＦジャーナル, 巻：1, 号：6, 開始ページ：23, 終了ページ：26, 2013年06月
  農林水産・食品産業技術振興協会, 日本語, 記事・総説・解説・論説等（その他）
  ISSN：2187-4948, CiNii Articles ID：10031159386, CiNii Books ID：AA12598816
• 健康機能性に着目した大麦食品の開発　　　　　　　　　　　　　　　
  円谷陽一; 小竹敬久; 川嶋かほる; 東海林義和
  食品と開発, 巻：48, 号：7, 開始ページ：89, 終了ページ：91, 2013年
  UBMメディア, 日本語
  ISSN：0911-3932, CiNii Articles ID：40019730927, CiNii Books ID：AN10051049
• AGPの糖鎖主鎖を分解するエンド-β-1,3-ガラクタナーゼ　　　　　　　　　　　　　　　
  小竹敬久; 平田尚弘; 出木雄太; 石黒真希; 一ノ瀬仁美; 金子哲; 五十嵐圭日子; 鮫島正浩; 円谷陽一
  日本植物学会大会研究発表記録, 巻：75th, 2011年
  J-Global ID：201102217514420113
• アラビノガラクタン-プロテイン糖鎖を分解するエンド-ガラクタナーゼ　　　　　　　　　　　　　　　
  平田尚弘; 出木雄太; 北澤仁成; 高田遼平; 小竹敬久; 一ノ瀬仁美; 金子哲; 石黒真希; 五十嵐圭日子; 鮫島正弘; 円谷陽一
  日本糖質学会年会要旨集, 巻：30th, 2011年
  J-Global ID：201102271678162594
• 過重力条件下におけるアラビノガラクタン-プロテインの遺伝子発現　　　　　　　　　　　　　　　
  小竹 敬久; 五十嵐 俊; 円谷 陽一; 曽我 康一; 若林 和幸; 保尊 隆享; Kotake Toshihisa; Igarashi Shun; Tsumuraya Yoichi; Soga Kouichi; Wakabayashi Kazuyuki; Hoson Takayuki
  宇宙利用シンポジウム = Space Utilization Research: Proceedings of Space Utilization Symposium, 号：25, 2009年03月
  第25回宇宙利用シンポジウム(2009年1月14日-15日, 宇宙航空研究開発機構宇宙科学研究本部相模原キャンパス)資料番号: AA0064297004
  宇宙航空研究開発機構宇宙科学研究本部, 日本語
  CiNii Articles ID：120006830492, CiNii Books ID：AN10324210
• 糖質分解酵素を用いたアラビノガラクタン-プロテイン糖鎖の構造改変　　　　　　　　　　　　　　　
  小竹 敬久; 高田 遼平; 北澤 仁成; 金子 哲; 五十嵐 圭日子; 鮫島 正浩; 円谷 陽一
  日本植物生理学会年会およびシンポジウム 講演要旨集, 巻：2009, 号：0, 開始ページ：483, 終了ページ：483, 2009年
  アラビノガラクタン-プロテイン（AGP）は原形質膜や細胞壁に存在する植物に普遍的なプロテオグリカンで、様々な生理現象に関与する。AGPの糖鎖はβ-3,6-ガラクタンを骨格とし、側鎖にはL-アラビノース（L-Ara）や4-O-メチルグルクロン酸（4-Me-GlcA）、グルクロン酸（GlcA）が結合する。細胞表層タンパク質の多くがアラビノガラクタン（AG）糖鎖化を受ける可能性が指摘されているが、AG糖鎖の生理機能は明らかにされていない。今回、糖質分解酵素を用いたAG糖鎖の構造改変を試みた。ゲノム情報を利用して真菌のα-L-アラビノフラノシダーゼ（Arafase）とβ-グルクロニダーゼ（GlcAase）をクローニングし、ピキア酵母により組換え酵素、rArafase及びrGlcAaseを作成した。rArafaseはin vitroでダイコン成根由来AGPに作用し、L-Araを遊離した。rGlcAaseは単独ではほとんどAGPに作用しなかったが、rArafaseと協調的に作用させると、L-Araとともに4-Me-GlcAやGlcAを遊離した。<I>Arafase</I>遺伝子と<I>GlcAase</I>遺伝子をシロイヌナズナに導入したところ、組換え植物ではそれぞれの活性が野生型植物の10倍以上に増加した。現在、AGP糖鎖の構造改変が表現形質に与える影響を解析している。
  日本植物生理学会
  J-Global ID：200902251712786030, CiNii Articles ID：130006990627
• 重力によるアズキ上胚軸の表層微小管の配向変化時に起こるγ-チューブリン複合体遺伝子レベルの一過的な増加　　　　　　　　　　　　　　　
  Soga Kouichi; Kotake Toshihisa; Wakabayashi Kazuyuki; KAMISAKA Seiichiro; HOSON Takayuki
  Journal of plant research, 巻：121, 号：5, 開始ページ：493, 終了ページ：498, 2008年09月01日
  Springer Japan, 英語
  ISSN：0918-9440, CiNii Articles ID：10022023402, CiNii Books ID：AA10900218
• 重力がアラビノガラクタン-プロテインの発現に与える影響
  小竹 敬久; 五十嵐 俊; 円谷 陽一; 曽我 康一; 若林 和幸; 保尊 隆享; Kotake Toshihisa; Igarashi Shun; Tsumuraya Yoichi; Soga Koichi; Wakabayashi Kazuyuki; Hoson Takayuki
  宇宙利用シンポジウム 第24回 平成19年度 = Space Utilization Research: Proceedings of the Twenty-fourth Space Utilization Symposium, 開始ページ：382, 終了ページ：384, 2008年03月
  資料番号: AA0063706110
  宇宙航空研究開発機構宇宙科学研究本部, 日本語
  CiNii Articles ID：120006830730
• 植物の抗重力反応におけるシグナル変換・伝達機構の解明
  保尊 隆享; 曽我 康一; 榊 剛; 村中 俊哉; 橋本 隆; 園部 誠司; 小竹 敬久; Hoson Takayuki; Soga Koichi; Sakaki Takeshi; Muranaka Toshiya; Hashimoto Takashi; Sonobe Seiji; Kotake Toshihisa
  宇宙利用シンポジウム 第24回 平成19年度 = Space Utilization Research: Proceedings of the Twenty-fourth Space Utilization Symposium, 開始ページ：390, 終了ページ：393, 2008年03月
  資料番号: AA0063706113
  宇宙航空研究開発機構宇宙科学研究本部, 日本語
  CiNii Articles ID：120006830733
• 重力による植物根の形態変化における細胞接着因子AGPの役割
  小竹 敬久; 曽我 康一
  埼玉大学地域オープンイノベーションセンター紀要, 号：1, 開始ページ：12, 終了ページ：14, 2008年
  Arabinogalactan-proteins (AGPs), a family of proteoglycans, are commonly found in higher plants and implicated in many physiological processes such as cell adhesion, cell-to-cell signaling, cell elongation, cell death, and stress responses. To address the molecular functions of AGP in the regulation of growth anisotropy of roots induced by the gravity signal, we visualized AGP species with GFP in living Arabidopsis plants. The dynamic changes of the gravity-responsive AGP species in the localization and accumulation were observed under the hypergravity condition. The results indicate that the expression of AGP genes is regulated by the magnitude of gravity. In the future study, the molecular functions of AGPs in the growth anisotropy should be clarified.
  埼玉大学総合研究機構地域オープンイノベーションセンター, 日本語
  ISSN：1883-8278, CiNii Articles ID：120001491448
• アラビノガラクタン-プロテイン分解酵素　　　　　　　　　　　　　　　
  一ノ瀬 仁美; 小竹 敬久; 円谷 陽一; 金子 哲
  Journal of applied glycoscience, 巻：55, 号：2, 開始ページ：149, 終了ページ：155, 2008年
  アラビノガラクタン-プロテイン(AGPs)は高等植物のプロテオグリカンの一種であり，その生長や発生への関与が示唆されている．また，食品素材・食品添加物として用いられているガムアラビックやカラマツアラビノガラクタンはAGPsの一種である．AGPsの糖鎖は，その分子の大部分を占め，β-1,3-ガラクタン主鎖にβ-1,6-ガラクタン側鎖が結合している．これらのガラクタン鎖を加水分解できる酵素はAGPs分解に重要であるが，その研究はきわめて少ない．われわれはPhanerochaete chrysosporium由来エキソ-β-1,3-ガラクタナーゼ(Pc1,3Gal43A)とTrichoderma viride由来エンド-β-1,6-ガラクタナーゼ(Tv6GAL)を初めてクローニングすることに成功した．Pc1,3Gal43Aは糖質加水分解酵素(GH)ファミリー43と糖結合モジュール(CBM)ファミリー35の二つのモジュールで構成されていた．本酵素は二つのガラクトース残基間のβ-1,3結合のみを加水分解するエキソ型酵素であるが，AGPsに作用した場合にはβ-1,6結合のガラクタン側鎖をバイパスしてガラクトースとβ-1,6-ガラクトオリゴ糖を生産した．また，C末端側のCBM35はβ-1,3-ガラクタンに特異的に結合した．Pc1,3Gal43Aの配列を用いたBLAST検索により見出されたClostridium thermocellum, Streptomyces avermitilis等の細菌や植物(Arabidopsis thaliana)の類似配列を発現させ，エキソ-β-1,3-ガラクタナーゼが生物界に広く存在することを明らかにした．一方，Tv6GALの配列を用いたBLAST検索より見出されたS. avermitilis由来の配列が，β-1,6-結合のガラクトースからなる基質のみを加水分解するエンド型酵素であることを明らかにした．
  日本応用糖質科学会, 英語
  DOI：https://doi.org/10.5458/jag.55.149
  DOI ID：10.5458/jag.55.149, ISSN：1344-7882, CiNii Articles ID：10020738828, CiNii Books ID：AA11809133
• 植物の糖ヌクレオチド合成を触媒する新規なピロホスホリラーゼ : 糖1-リン酸に対して幅広い基質特異性. 各種のUDP-糖合成への利用に期待　　　　　　　　　　　　　　　
  円谷 陽一; 小竹 敬久
  化学と生物, 巻：45, 号：3, 開始ページ：163, 終了ページ：164, 2007年03月01日
  日本語
  ISSN：0453-073X, CiNii Articles ID：10018572759, CiNii Books ID：AN00037573
• 重力シグナルがイネのβ-1,3:1,4-グルカン合成活性に与える影響
  小竹 敬久; 金原 知也; 円谷 陽一; 曽我 康一; 若林 和幸; 保尊 隆享; Kotake Toshihisa; Kinpara Tomoya; Tsumuraya Yoichi; Soga Koichi; Wakabayashi Kazuyuki; Hoson Takayuki
  宇宙利用シンポジウム 第23回 平成18年度 = Space Utilization Research: Proceedings of the Twenty-third Space Utilization Symposium, 開始ページ：371, 終了ページ：374, 2007年03月
  資料番号: AA0063349106
  宇宙航空研究開発機構宇宙科学研究本部, 日本語
  CiNii Articles ID：120006830848
• アラビノガラクタン-プロテインの糖鎖のβ-グルクロニダーゼによる分析　　　　　　　　　　　　　　　
  古西智之; 小竹敬久; ソラヤディナ; 金子哲; 五十嵐圭日子; 鮫島正浩; 円谷陽一
  日本植物生理学会年会要旨集, 巻：48th, 2007年
  J-Global ID：200902217440780670
• アラビノガラクタン-プロテインの糖鎖のβ-グルクロニダーゼによる分解　　　　　　　　　　　　　　　
  古西智之; 小竹敬久; SORAYA Dina; 松岡浩司; 小山哲夫; 金子哲; 五十嵐圭日子; 鮫島正浩; 円谷陽一
  日本糖質学会年会要旨集, 巻：27th, 2007年
  J-Global ID：200902224219842160
• Isolation and characterization of a novel bifunctional L-fukokinase/GDP-L-fucose pyrophosphorylase in Arabidopsis　　　　　　　　　　　　　　　
  Toshihisa Kotake; Sachiko Hojo; Yoichi Tsumuraya
  巻：48, 開始ページ：S80, 終了ページ：S80, 2007年
  英語, 研究発表ペーパー・要旨（国際会議）
  ISSN：0032-0781, Web of Science ID：WOS:000245922700315
• AMOR, a 70-kDa protein from the ovule, induces competence of the pollen tube to respond to the final-step guidance　　　　　　　　　　　　　　　
  INATSUGI Rie; SASAKI Narie; KOTAKE Toshihisa; TSUMURAYA Yoichi; KUROIWA Tsuneyosi; NAKANO Akihiko; HIGASHIYAMA Tetsuya
  Journal of plant research, 巻：119, 開始ページ：169, 終了ページ：170, 2006年12月01日
  英語
  ISSN：0918-9440, CiNii Articles ID：10019309892, CiNii Books ID：AA10900218
• 植物の抗重力反応解明研究班ＷＧの活動報告　　　　　　　　　　　　　　　
  保尊 隆享; 神阪 盛一郎; 高橋 秀幸; 山下 雅道; 飯田 秀利; 村中 俊哉; 橋本 隆; 園部 誠司; 谷本 英一; 西谷 和彦; 小竹 敬久; 若林 和幸; 曽我 康一; Hoson Takayuki; Kamisaka Seiichiro; Takahashi Hideyuki; Yamashita Masamichi; Iida Hidetoshi; Muranaka Toshiya; Hashimoto Takashi; Sonobe Seiji; Tanimoto Eiichi; Nishitani Kazuhiko; Kotake Toshihisa; Wakabayashi Kazuyuki; Soga Kouichi
  宇宙利用シンポジウム = Space Utilization Research: Proceedings of Space Utilization Symposium, 号：22, 2006年03月
  第22回宇宙利用シンポジウム(2006年1月17日-19日, 日本学術会議6階会議室 六本木、東京)共催: 日本学術会議著者人数: 13人資料番号: AA0064113098
  宇宙航空研究開発機構宇宙科学研究本部, 日本語
  CiNii Articles ID：120006830958, CiNii Books ID：AN10324210
• PCP Award - Arabidopsis TERMINAL FLOWER2, a Heterochromatin Protein 1 homolog, regulates flowering time.　　　　　　　　　　　　　　　
  T Kotake; S Takada; K Nakahigashi; O Masaaki; K Goto
  巻：46, 開始ページ：S24, 終了ページ：S24, 2005年
  英語, 研究発表ペーパー・要旨（国際会議）
  ISSN：0032-0781, Web of Science ID：WOS:000228104100094
• Phanerochaete chrysosporium β-1,3-ガラクタナーゼのクローニングとPichia pastorisでの発現,精製とその性質　　　　　　　　　　　　　　　
  一ノ瀬仁美; 吉田誠; 五十嵐圭日子; 鮫島正浩; 小竹敬久; 円谷陽一; 小林秀行; 金子哲
  日本農芸化学会大会講演要旨集, 巻：2004, 2004年
  J-Global ID：200902231713654896
• Molecular cloning of glycosyl hydrolases that act on the carbohydrate moieties of arabinogalactan-protein　　　　　　　　　　　　　　　
  T Kotake; K Tsuchiya; S Kaneko; MA Haque; H Kobayashi; Y Tsumuraya
  巻：45, 開始ページ：S88, 終了ページ：S88, 2004年
  英語, 研究発表ペーパー・要旨（国際会議）
  ISSN：0032-0781, Web of Science ID：WOS:000220592700346
• Expression and Function of Cell Wall-Bound Cationic Peroxidase in Asparagus Somatic Embryogenesis　　　　　　　　　　　　　　　
  Hiroyuki Takeda; Toshihisa Kotake; Naoki Nakagawa; Naoki Sakurai; Donald J. Nevins
  巻：131, 号：4, 開始ページ：1765, 終了ページ：1774, 2003年04月01日, ［査読有り］
  Abstract
  
  Cultured asparagus (Asparagus officinalis L. cv Y6) cells induced to regenerate into whole plants through somatic embryogenesis secreted a 38-kD protein into cell walls. The full-length cDNA sequence of this protein (Asparagus officinalisperoxidase 1 [AoPOX1]) determined by reverse transcriptase-polymerase chain reaction showed similarity with plant peroxidases.AoPOX1 transcripts were particularly abundant during early somatic embryogenesis. To evaluate the in vivo function of AoPOX1 protein, purified recombinant AoPOX1 protein was reacted with a series of phenolic substrates. The AoPOX1 protein was effective in the metabolism of feruloyl (o-methoxyphenol)-substituted substrates, including coniferyl alcohol. The reaction product of coniferyl alcohol was fractionated and subjected to gas chromatography-mass spectrometry analysis and 1H-nuclear magnetic resonance analysis, indicating that the oxidation product of coniferyl alcohol in the presence of AoPOX1 was dehydrodiconiferyl alcohol. The concentration of dehydrodiconiferyl alcohol in the cultured medium of the somatic embryos was in the range of 10−8  m. Functions of the AoPOX1 protein in the cell differentiation are discussed.
  英語
  DOI：https://doi.org/10.1104/pp.102.014654
  DOI ID：10.1104/pp.102.014654, ISSN：0032-0889, eISSN：1532-2548, CiNii Articles ID：80015933875, PubMed ID：12692335, Web of Science ID：WOS:000185076400026
• シロイヌナズナの花成抑制因子TFL2はSwi6/HP1様タンパク質をコードし、Zn-fingerタンパク質と相互作用する (地域振興作物への病害抵抗性に関する基礎研究と遺伝子工学的手法による高度病害抵抗性付与技術の開発) -- (植物生殖成長のキープロセスを統御する分子機構の解明(CREST研究課題))　　　　　　　　　　　　　　　
  戒能 智宏; 小竹 敬久; 高田 忍
  岡山県生物科学総合研究所研究年報, 開始ページ：37, 終了ページ：41, 2001年
  岡山県生物科学総合研究所, 日本語
  CiNii Articles ID：40015237201, CiNii Books ID：AA1182211X
• シロイヌナズナのTERMINAL FLOWER2(TFL2)遺伝子はSwi6/HP1様のタンパク質をコードし、花成促進遺伝子FTの発現を負に制御している (地域振興作物への病害抵抗性に関する基礎研究と遺伝子工学的手法による高度病害抵抗性付与技術の開発) -- (植物生殖成長のキープロセスを統御する分子機構の解明(CREST研究課題))　　　　　　　　　　　　　　　
  高田 忍; 小竹 敬久; 戒能 智宏
  岡山県生物科学総合研究所研究年報, 開始ページ：43, 終了ページ：47, 2001年
  岡山県生物科学総合研究所, 日本語
  CiNii Articles ID：40015237202, CiNii Books ID：AA1182211X
• Characterization of peroxidase Secreted from Asparagus Somatic Embryo :　　　　　　　　　　　　　　　
  TAKEDA Hiroyuki; KOTAKE Toshihisa; NAKAGAWA Naoki; SAKURAI Naoki
  Plant and cell physiology, 巻：42, 開始ページ：s73, 2001年
  Japanese Society of Plant Physiologists, 英語
  ISSN：0032-0781, CiNii Articles ID：110003715425, CiNii Books ID：AA0077511X
• シロイヌナズナの花成制御因子、TFL1およびFTと相互作用する因子の探索 (地域振興作物への病害抵抗性に関する基礎研究と遺伝子工学的手法による高度病害抵抗性付与技術の開発) -- (生体高分子の植物細胞間移動に対する抵抗性を付与する技術の開発)　　　　　　　　　　　　　　　
  小竹 敬久; 後藤 弘爾
  岡山県生物科学総合研究所研究年報, 開始ページ：27, 終了ページ：30, 2000年
  岡山県生物科学総合研究所, 日本語
  CiNii Articles ID：40005384378, CiNii Books ID：AA1182211X
• CLONING OF PEROXIDASE SECRETED FROM ASPARAGUS SOMATIC EMBRYO :　　　　　　　　　　　　　　　
  TAKEDA Hiroyuki; KOHMURA Hiroyuki; KOTAKE Toshihisa; NAKAGAWA Naoki; SAKURAI Naoki
  Plant and cell physiology, 巻：41, 開始ページ：s191, 2000年
  Japanese Society of Plant Physiologists, 英語
  ISSN：0032-0781, CiNii Articles ID：110003722610, CiNii Books ID：AA0077511X
• GENE EXPRESSIONS OF EXO-, ENDO-1,3 : 1,4-AND ENDO-1,4-β-GLUCANASES IN BARLEY COLEOPTILE :　　　　　　　　　　　　　　　
  KOTAKE Toshihisa; NAKAGAWA Naoki; SAKURAI Naoki
  Plant and cell physiology, 巻：41, 開始ページ：s190, 2000年
  Japanese Society of Plant Physiologists, 英語
  ISSN：0032-0781, CiNii Articles ID：110003722603, CiNii Books ID：AA0077511X
• Hormonal expression of endo- and exo-glucanase in barley coleoptiles　　　　　　　　　　　　　　　
  KOTAKE Toshihisa; NAKAGAWA Naoki; SAKURAI Naoki
  Plant and cell physiology, 巻：39, 開始ページ：S79, 終了ページ：S79, 1998年05月
  英語
  ISSN：0032-0781, CiNii Articles ID：10003751783, CiNii Books ID：AA0077511X
• An exo-glucanase involved in elongation of pollen tube　　　　　　　　　　　　　　　
  LI Yi-Qin; KOTAKE Toshihisa; SAKURAI Naoki
  Plant and cell physiology, 巻：39, 開始ページ：S49, 終了ページ：S49, 1998年05月
  英語
  ISSN：0032-0781, CiNii Articles ID：10003751663, CiNii Books ID：AA0077511X
• Purification and characterization of wall-bound exo- and endo-glucanase in Gramineae　　　　　　　　　　　　　　　
  KOTAKE Toshihisa; NAKAGAWA Naoki; SAKURAI Naoki
  Plant and cell physiology, 巻：38, 開始ページ：s128, 1997年03月
  英語
  ISSN：0032-0781, CiNii Articles ID：10004345909, CiNii Books ID：AA0077511X
• Purification and characterization of β-D-glucanase involved in cell elongation　　　　　　　　　　　　　　　
  KOTAKE T.; NAKAGAWA N.; SAKURAI N.
  Plant and cell physiology, 巻：37, 開始ページ：124, 終了ページ：124, 1996年03月
  英語
  ISSN：0032-0781, CiNii Articles ID：10002708282, CiNii Books ID：AA0077511X

• 植物バイオマスを構成するヘミセルロースの修飾パターンと立体構造　　　　　　　　　　　　　　　
  吉見 圭永; Tryfona Theodora; 小竹 敬久; Dupree Paul, ［共著］
  応用糖質科学, 2024年12月, ［査読有り］, ［国際共著］
  担当ページ：187-195
• 植物内在性の細胞壁多糖分解酵素の多様な性質とはたらき　　　　　　　　　　　　　　　
  吉田 光毅; 吉見 圭永; 高橋 大輔; 小竹 敬久, ［共著］
  応用糖質科学, 2024年12月, ［査読有り］
  担当ページ：233-241
• 環境微生物の呼吸と浄化技術の進歩　　　　　　　　　　　　　　　
  板谷光泰; 大西純一; 小竹敬久; 定家義人; 定家多美子; 田中耕生; 松岡聡; 松本幸次; 吉田健一, ［共著］
  日本工業出版, 2017年08月
• 植物のプロテオグリカン，アラビノガラクタン-プロテインの構造と機能　　　　　　　　　　　　　　　
  円谷 陽一; 小竹 敬久, ［共著］
  生化学, 2017年08月
• 植物のプロテオグリカン　　　　　　　　　　　　　　　
  小竹 敬久
  生物工学会誌「バイオミディア」, 2016年12月
• 植物細胞壁実験法　　　　　　　　　　　　　　　
  石井, 忠; 石水, 毅; 梅澤, 俊明; 加藤, 陽治; 岸本, 崇生; 小西, 照子; 松永, 俊朗, ［分担執筆］
  弘前大学出版会, 2016年02月
  日本語, 総ページ数：xi, 403p
  CiNii Books：http://ci.nii.ac.jp/ncid/BB20768305
  ISBN：9784907192211, CiNii Books ID：BB20768305
• 植物細胞壁　　　　　　　　　　　　　　　
  西谷, 和彦; 梅澤, 俊明; 講談社サイエンティフィク, ［分担執筆］
  講談社, 2013年03月
  日本語, 総ページ数：x, 349p
  CiNii Books：http://ci.nii.ac.jp/ncid/BB11991280
  ISBN：9784061538184, CiNii Books ID：BB11991280
• 植物生体内で単糖類はどのようにリサイクルされるか?　　　　　　　　　　　　　　　
  小竹 敬久; 円谷 陽一, ［共著］
  化学と生物, 2010年12月
• Arabinogalactan-proteins degrading enzymes　　　　　　　　　　　　　　　
  Ichinose H; Kotake T; Tsumuraya Y; Kaneko S
  Journal of Applied Glycoscience, 2008年
• 植物の糖ヌクレオチド合成を触媒する新規なピロホスホリラーゼ －糖 1-リン酸に対して幅広い基質特異性、各種のUDP-糖合成への利用に期待－　　　　　　　　　　　　　　　
  円谷陽一; 小竹敬久, ［共著］
  化学と生物, 2007年

• 2019年10月 - 現在, 日本応用糖質科学会
• 2004年08月 - 現在, 日本糖質学会
• 2002年01月 - 現在, 日本植物学会
• 1996年03月 - 現在, 日本植物生理学会

• 機能性を高めるグルコマンナン高アセチル化の分子メカニズム　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 2023年04月01日 - 2027年03月31日
  小竹 敬久; 山口 雅利, 埼玉大学
  配分額（総額）：18720000, 配分額（直接経費）：14400000, 配分額（間接経費）：4320000
  課題番号：23K26827
• 機能性を高めるグルコマンナン高アセチル化の分子メカニズム　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(B), 基盤研究(B), 2023年04月 - 2027年03月
  小竹 敬久, 埼玉大学
  配分額（総額）：18720000, 配分額（直接経費）：14400000, 配分額（間接経費）：4320000
  課題番号：23H02134
• 細胞外プロテオグリカンによる植物のからだ作りの分子機構　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 学術変革領域研究(A), 学術変革領域研究(A), 2023年04月 - 2025年03月
  小竹 敬久, 埼玉大学
  配分額（総額）：12740000, 配分額（直接経費）：9800000, 配分額（間接経費）：2940000
  課題番号：23H04302
• 科学的に探究する学習活動における効果的な生物教材と個別最適な学習プログラムの開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 2022年04月 - 2025年03月
  片山 豪; 小竹 敬久; 真壁 和裕; 谷 友和; 岩室 祥一; 網本 貴一, 高崎健康福祉大学
  配分額（総額）：4290000, 配分額（直接経費）：3300000, 配分額（間接経費）：990000
  課題番号：22K02581
• 植物体のしなやかさを生み出す非セルロース性細胞壁成分の構造力学的・化学的特性　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 新学術領域研究(研究領域提案型), 新学術領域研究(研究領域提案型), 2018年06月29日 - 2023年03月31日
  小竹 敬久; 石水 毅, 埼玉大学
  配分額（総額）：78520000, 配分額（直接経費）：60400000, 配分額（間接経費）：18120000
  本研究は、細胞壁の非セルロース性成分の機能に着目して、植物体にしなやかで強い力学特性が付与される仕組みを解明することを目指している。細胞外プロテオグリカンであるアラビノガラクタン-プロテイン（AGP）は、糖鎖の重要性や分子機能が分かっていない。そこで、微生物由来の強力なAG糖鎖分解酵素が発現する植物を作出し、2019年度はこの植物の解析を進め、AG糖鎖を特異的に破壊すると著しい組織形態の異常が起きることを明らかにした（論文投稿中）。今後は、AG糖鎖構造と組織・細胞形態、植物体の物性の関係を整理し、機能に重要な糖鎖構造を同定する。
  AG糖鎖の働きに関与する新規因子の発見を目指して、AGPの阻害剤であるヤリブ試薬に高感受性の変異体と耐性の変異体のスクリーニングを実施した。ヤリブ試薬存在下で根の成長が著しく阻害される高感受性変異体が２株、成長の阻害が顕著に抑えられる耐性の変異体が１株得られた。また、ペクチンやセルロースなどのAGP以外の細胞壁成分との機能上の関係を整理する目的で、既存の細胞壁変異体のヤリブ試薬感受性の解析も実施し、これらの中から、２株の高感受性変異体と１株の耐性変異体を見つけた。今後、これら変異体の原因遺伝子や物性、細胞壁の変化、組織形態の変化を解析する。
  ペクチンには、HGとRG-I 、RG-IIの３領域が存在するが、これらの分子機能の違いがわかっていない。2019年度は、HGやRG-IIの構造が異常な変異体について、植物体の物性や細胞壁成分の変化を調べた。RG-IIが異常な変異体では、胚軸の伸展性が顕著に低下し、RG-Iの特定の成分が著しく増加していることがわかった。この変化は、RG-IIの異常による力学特性の変化をRG-Iで補償する反応である可能性がある。今後は、遠心過重力環境も利用して、植物体の優れた力学特性に貢献する細胞壁成分や組織構造の同定を進める。
  課題番号：18H05495
• 植物の光依存的なビタミンC合成に関わる未知制御機構　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 2019年04月01日 - 2022年03月31日
  小竹 敬久, 埼玉大学
  配分額（総額）：4420000, 配分額（直接経費）：3400000, 配分額（間接経費）：1020000
  光エネルギーを利用して光合成を行っている植物は、時に強光にさらされ、細胞内が活性酸素種に曝される。過酸化水素などの活性酸素種は、DNAやタンパク質、生体膜の損傷を起こすため、植物はこれらをビタミンCなどにより消去している。ビタミンC量は明条件では多いが、暗条件では少なく、合成が明・暗条件で制御されている。
  植物の主要なビタミンC合成経路であるD-Man/L-Gal経路は10反応で構成されるが、シロイヌナズナでは、VTC1によって触媒されるGDP-マンノース（GDP-Man）合成反応が律速反応であることが知られている。VTC1は暗条件でプロテアソームによる分解を受けており、この分解は、COP9シグナロソームの構成因子であるCSN5Bに導かれるが、光依存的な分解のメカニズムは不明である。そこで本研究では、VTC1相互作用因子であるKJC1の機能に着目して、VTC1分解が光によって制御される仕組みの解明を目指している。
  2019年度は、ゲノミックのVTC1遺伝子にFLAG配列を導入したgFLAG-VTC1遺伝子導入植物の確立を行った。この人工遺伝子を導入したvtc1変異体ではビタミンCレベルやGDP-Man合成活性が回復することを確認し、野生型植物、kjc1変異体、kjc2変異体で、独立した形質転換植物を各４ライン以上作成した。kjc1変異体では、FLAG-VTC1の蓄積量が野生型植物の3%以下になっており、KJC1がVTC1の分解を抑制していることが支持された。今後は、明暗サイクルにおける、ビタミンCレベル、GDP-Man合成活性、VTC1タンパク質量の変化を解析する。また、VTC1と相互作用する因子の探索も進める。
  課題番号：19K06702
• 植物細胞壁損傷の感知による植食性昆虫食害の認識機構　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 2018年04月01日 - 2021年03月31日
  新屋 友規; 小竹 敬久, 岡山大学
  配分額（総額）：4420000, 配分額（直接経費）：3400000, 配分額（間接経費）：1020000
  植物を食害する植食性昆虫に対して効果的に植物免疫システムを活性化するうえで、植物の食害認識は重要な系のひとつである。植物の食害認識では「昆虫由来の分子」に加え、「食害にともない産生される分子」や「自己組織の損傷」を認識すると考えられているが、報告例が限られている。本年度は、植物の昆虫認識分子機構の解明に向けて、イネとクサシロキヨトウの相互作用に注目し、食害時の細胞壁損傷にともない産生するデンジャーシグナル糖鎖分子によって誘導される防御応答の解析を初年度に引き続き行うとともに、デンジャーシグナル糖鎖産生の分子メカニズムの解析を行った。
  初年度において、デンジャーシグナル糖鎖の産生に重要な細胞壁分解酵素が、食害認識に重要なクサシロキヨトウ吐き戻し液中に存在することを見出していた。本年度、この酵素が植物に由来するのか、あるいは昆虫に由来するのかを明らかにするために実験を行ったところ、クサシロキヨトウの腸内に存在する細菌が産生している可能性がみえてきた。クサシロキヨトウ腸内細菌の単離・同定および菌叢解析を行ったところ、当該酵素遺伝子を有している複数の腸内細菌が存在することが明らかになった。これらの結果より、イネを食餌したクサシロキヨトウの腸内において、腸内細菌が産生する細胞壁酵素がイネ細胞壁よりデンジャーシグナル糖鎖分子を産生し、この分子が吐き戻し液に混在することで、クサシロキヨトウ食害時のイネの害虫認識や防御応答誘導に影響することが示唆された。
  課題番号：18K05558
• L-アラビノース合成系の起源と生理的意義の解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 2016年04月01日 - 2019年03月31日
  小竹 敬久, 埼玉大学
  配分額（総額）：4940000, 配分額（直接経費）：3800000, 配分額（間接経費）：1140000
  L-アラビノースは動物には見られない植物特有の糖である。植物生体内でL-アラビノースは、糖ヌクレオチドであるUDP-L-アラビノースの形で作られる。UDP-L-アラビノースを新生経路で合成する反応は、UDP-キシロースのC-4エピマー化だけであり、この反応は細胞質基質ではUDP-グルコース4-エピメラーゼの一種であるUGE1により触媒される。この活性を持たないUGE2との間でアミノ酸残基を交換した変異タンパク質を作成したところ、３つのアミノ酸残基がこの活性に重要であることがわかった。UGEがこれらの残基を持つことで、陸上植物は細胞質基質でのUDP-L-アラビノース合成能を獲得したと考えられる。
  課題番号：16K07391
• 植物の細胞機能や発生・分化における細胞壁多糖・糖タンパク質の機能の解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 新学術領域研究(研究領域提案型), 新学術領域研究(研究領域提案型), 2012年06月28日 - 2017年03月31日
  佐藤 忍; 円谷 陽一; 小竹 敬久; 岩井 宏暁; 古川 純, 筑波大学
  配分額（総額）：90090000, 配分額（直接経費）：69300000, 配分額（間接経費）：20790000
  1,イネのペクチンアラビノース側鎖が花粉細胞壁の形成発達に，雌しべにおけるペクチンのメチル化度調節が花粉管メカニカルガイダンスに重要であること及び器官脱離時の離層において特徴的な細胞壁の再編が生じることが示された。
  2,シロイヌナズナ切断花茎の組織癒合ではオーキシンや転写制御因子等の下流でXTH20等が髄の細胞分裂に関わり，根で地上部ジベレリンや短日/低温に応答する鉄輸送体やCLE6ペプチド，導管液タンパク質や糖質に関連する遺伝子が地上部の生育に関わることが示された。
  3,細胞表層プロテオグリカンであるアラビノガラクタン-プロテインの糖鎖が細胞形態や分化に不可欠であることが示された。
  課題番号：24114006
• 植物の重力の大きさに応答した遺伝子発現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 基盤研究(C), 基盤研究(C), 2013年04月01日 - 2016年03月31日
  小竹 敬久; 曽我 康一, 埼玉大学
  配分額（総額）：5070000, 配分額（直接経費）：3900000, 配分額（間接経費）：1170000
  植物の成長は重力の大きさによって変化する。表層微小管の配向制御に関わるMAP65-1遺伝子の下胚軸における発現・蓄積をGFP融合遺伝子を導入したシロイヌナズナを用いて解析した。MAP65-1の発現は成長の盛んな胚軸上部で高く、逆に基部では低かった。MAP65-1の5’側領域を段階的に削ったところ、この発現には上流1.1～0.7 kbの領域が重要であることがわかった。遠心過重力環境下での発現変化を解析したが、発現の個体差が大きく、重力の大きさへの応答に関わる発現制御領域は特定できなかった。
  課題番号：25514001
• 高等植物におけるGDP-グルコース合成経路とその生理的役割の解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 2010年 - 2012年
  小竹 敬久, 埼玉大学
  配分額（総額）：4160000, 配分額（直接経費）：3200000, 配分額（間接経費）：960000
  機能不明の糖ヌクレオチド合成酵素、KONJAC(KJC)1、2のGDP-糖合成における役割を解析した。シロイヌナズナのkjc1変異体では、細胞壁グルコマンナン量が野生型植物の50%に減少した。大腸菌で作成した組換えKJCタンパク質は、それ自体は活性を持たなかったが、VTC1の活性を顕著に増加させた。これらのことから、KJCタンパク質にはVTC1によるGDP-マンノースやGDP-グルコースの合成を高める働きがあると考えられる。
  課題番号：22770030
• 植物が有する特異な糖ヌクレオチド代謝経路の解明　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 2005年 - 2006年
  小竹 敬久, 埼玉大学
  配分額（総額）：1900000, 配分額（直接経費）：1900000
  植物細胞壁を構成する多糖類は、UDP-糖やGDP-糖を基質として、糖転移酵素の働きにより合成される。糖ヌクレオチドの代謝は直接的に細胞壁多糖類の合成を制御している。植物の糖ヌクレオチド合成経路のうち、遊離単糖をUDP-糖やGDP-糖に変換するsalvage経路には未解明な反応が多い。本研究では、シロイヌナズナとイネのゲノムを利用して、salvage経路で働く植物特有の糖ヌクレオチド合成酵素、UDP-糖ピロホスホリラーゼ(USP)及び二機能性L-フコキナーゼ/GDP-L-Fucピロホスホリラーゼ(FKGP)を同定し、これらの特性や生理機能を明らかにした。
  USPは、各種糖1-リン酸をUTPの存在下で各種UDP-糖に変換する活性を有し、salvage経路で、UDP-グルコース、UDP-ガラクトース、UDP-L-アラビノース、UDP-グルクロン酸の合成を触媒することが示された。シロイヌナズナではUSP遺伝子を欠損すると花粉が正常に発達せず、優性不稔となった。
  FKGPは、L-フコキナーゼ活性とGDP-L-Fucピロホスホリラーゼ活性を有し、L-Fucのsalvage経路における連続する2つの反応(L-Fucのリン酸化とGDP-L-Fucへの変換)を触媒する。FKGPはL-Fuc 1-リン酸への親和性が高く、連続する2つの反応を効率的に触媒すると考えられる。
  糖ヌクレオチド合成のデノボ経路で働く酵素の多くは動物で同定された酵素の相同タンパク質であるが、salvage経路で働くUSP、FKGPは植物特有のタンパク質であった。このことは、植物が活発な細胞壁多糖類の合成・分解に合わせて、単糖のsalvage経路を発達させたことを示唆する。
  課題番号：17770028
• 伸長成長に関与する植物細胞壁結合タンパク質の単離・精製　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 1998年 - 1999年
  小竹 敬久, 広島大学
  配分額（総額）：1800000, 配分額（直接経費）：1800000
  課題番号：97J03682