Sakihama Yasuko
| Research Faculty of Agriculture Fundamental AgriScience Research Applied Bioscience | Professor |
Last Updated :2025/03/17
■Researcher basic information
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Researcher ID
- B-1047-2012
J-Global ID
Research Keyword
Research Field
- Life sciences, Food sciences, 抗酸化
- Environmental science/Agricultural science, Conservation science (plants), 植物・微生物相互作用
- Life sciences, Food sciences, 機能性植物二次代謝物
- Environmental science/Agricultural science, Conservation science (plants), 環境ストレス応答
- Life sciences, Plants: molecular biology and physiology, 環境適応
Educational Organization
- Bachelor's degree program, School of Agriculture
- Master's degree program, Graduate School of Agriculture
- Doctoral (PhD) degree program, Graduate School of Agriculture
■Career
Career
■Research activity information
Awards
Papers
- Effect of mixed light emitting diode spectrum on antioxidants content and antioxidant activity of red lettuce grown in a closed soilless system
Sopanat Sawatdee, Teeraya Jarunglumlert, Prasert Pavasant, Yasuko Sakihama, Adrian E. Flood, Chattip Prommuak
BMC Plant Biology, 23, 1, Dec. 2023, [Peer-reviewed]
Scientific journal, Background: Light spectra have been demonstrated to result in different levels of comfort or stress, which affect plant growth and the availability of health-promoting compounds in ways that sometimes contradict one another. To determine the optimal light conditions, it is necessary to weigh the vegetable’s mass against the amount of nutrients it contains, as vegetables tend to grow poorly in environments where nutrient synthesis is optimal. This study investigates the effects of varying light conditions on the growth of red lettuce and its occurring nutrients in terms of productivities, which were determined by multiplying the total weight of the harvested vegetables by their nutrient content, particularly phenolics. Three different light-emitting diode (LED) spectral mixes, including blue, green, and red, which were all supplemented by white, denoted as BW, GW, and RW, respectively, as well as the standard white as the control, were equipped in grow tents with soilless cultivation systems for such purposes. Results: Results demonstrated that the biomass and fiber content did not differ substantially across treatments. This could be due to the use of a modest amount of broad-spectrum white LEDs, which could help retain the lettuce’s core qualities. However, the concentrations of total phenolics and antioxidant capacity in lettuce grown with the BW treatment were the highest (1.3 and 1.4-fold higher than those obtained from the control, respectively), with chlorogenic acid accumulation (8.4 ± 1.5 mg g− 1 DW) being particularly notable. Meanwhile, the study observed a high glutathione reductase (GR) activity in the plant achieved from the RW treatment, which in this study was deemed the poorest treatment in terms of phenolics accumulation. Conclusion: In this study, the BW treatment provided the most efficient mixed light spectrum to stimulate phenolics productivity in red lettuce without a significant detrimental effect on other key properties. - Isolation of High-Purity Betanin from Red Beet and Elucidation of Its Antioxidant Activity against Peroxynitrite: An in vitro Study
Yasuko Sakihama, Takashi Kato, Sopanat Sawatdee, Yo Yakushi, Junichi Asano, Hiroyo Hayashi, Yuya Goto, Makoto Hashimoto, Yasuyuki Hashidoko
International Journal of Molecular Sciences, 21 Oct. 2023, [Peer-reviewed], [Invited], [Lead author, Corresponding author]
Scientific journal - Accumulation of squalene in filamentous fungi Trichoderma virens PS1-7 in the presence of butenafine hydrochloride, squalene epoxidase inhibitor. -Biosynthesis of 13C-enriched squalene
Wen Zhang, Kazu Sunami, Shuo Liu, Zihan Zhuang, Yasuko Sakihama, Da-Yang Zhou, Takeyuki Suzuki, Yuta Murai, Makoto Hashimoto, Yasuyuki Hashidoko
Bioscience, Biotechnology, and Biochemistry, Oxford University Press (OUP), 01 Aug. 2023, [Peer-reviewed]
Scientific journal, Abstract
Squalene is a triterpenoid compound and widely used in various industries such as medicine and cosmetics due to its strong antioxidant and anticancer properties. The purpose of this study is to increase the accumulation of squalene in filamentous fungi using exogeneous butenafine hydrochloride, which is an inhibitor for squalene epoxidase. The detailed settings achieved that the filamentous fungi, Trichoderma virens PS1-7, produced squalene up to 429.93 ± 51.60 mg/L after culturing for 7 days in the medium consisted of potato infusion with glucose at pH 4.0, in the presence of 200 μM butenafine. On the other hand, no squalene accumulation was observed without butenafine. This result indicated that squalene was biosynthesized in the filamentous fungi PS1-7 which can be used as a novel source of squalene. In addition, we successfully obtained highly 13C-enriched squalene by using [U-13C6]-glucose as a carbon source replacing normal glucose. - Influence of acute beetroot juice supplementation on cold-induced vasodilation and fingertip rewarming
Hitoshi Wakabayashi, Koji Sugiyama, Shinichi Suzuki, Yasuko Sakihama, Makoto Hashimoto, Martin J. Barwood
European Journal of Applied Physiology, Springer Science and Business Media LLC, 28 Oct. 2022, [Peer-reviewed]
Scientific journal - Synthesis of (Trifluoromethyldiazirinyl)phenylboronic Acid Derivatives for Photoaffinity Labeling
Makoto Hashimoto, Manami Hashinoki, Natsumi Kurokawa, Yuta Murai, Zetryana Puteri Tachrim, Yasuko Sakihama, Takeyuki Suzuki
HETEROCYCLES, 103, 1, 392, 392, The Japan Institute of Heterocyclic Chemistry, 2021, [Peer-reviewed]
Scientific journal - Phenazine-1-carboxylic acid (PCA) produced by Paraburkholderia phenazinium CK-PC1 aids postgermination growth of Xyris complanata seedlings with germination induced by Penicillium rolfsii Y-1
Masataka Hane, Hanny C. Wijaya, Yanetri A. Nyon, Yasuko Sakihama, Makoto Hashimoto, Hideyuki Matsuura, Yasuyuki Hashidoko
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 85, 1, 77, 84, OXFORD UNIV PRESS, Jan. 2021, [Peer-reviewed], [Corresponding author], ［Internationally co-authored］, [International Magazine]
English, Scientific journal, Symbiosis of Penicillium rolfsii Y-1 is essential for the seed germination of Hawaii yellow-eyed grass (Xyris complanata). However, the local soil where the plants grow naturally often suppresses the radicle growth of the seedlings. This radicle growth was drastically restored by coinoculation of Paraburkholderia phenazinium isolate CK-PC1, which is a rhizobacterium of X. complanata. It was found that the isolate CK-PC1 produced phenazine-1-carboxylic acid (PCA, 1) as a major metabolite. The biological effects of PCA (1) were investigated using the seeds of X. complanata and Mung bean (Vigna radiata) and it was uncovered that the symbiosis of the isolate CK-PC1was essential for the postgermination growth of X. complanata and the metabolite PCA (1) might partially contribute to promote the growth of the plants. - SYNTHESIS OF DEUTERATED CYCLODOPA WITH HYDROGEN/DEUTERIUM EXCHANGE
Tachrim, Zetryana Puteri, Nakagawa, Shiori, Nakamura, Tadashi, Ohashi, Fumina, Kurokawa, Natsumi, Wakasa, Haruna, Tokoro, Yurika, Sakihama, Yasuko, Hashidoko, Yasuyuki, Suzuki, Takeyuki, Hashimoto, Makoto
HETEROCYCLES, 99, 1, 404, 414, PERGAMON-ELSEVIER SCIENCE LTD, Apr. 2019, [Peer-reviewed], [International Magazine]
English, Scientific journal, CycloDOPA (5,6-dihydroxy-indoline-2-carboxylic acid, leukodopachrome) is one of metabolites derived from tyrosine, one of intermediate in melanin formation (mammalian) and betanidin main skeleton (betalain pigment in plant). Synthesis of deuterated cyclodopa via hydrogen/deuterium exchange by utilization of deuterium chloride (DCl) and deuterated triflic acid (TfOD) are reported. The novel fully deuterated aromatic cycloDOPA derivative can be formed depending on temperature and time of H/D exchange condition. The complete study of H/D exchange resulted in the selective deuterium between 4- and/or 7-position of aromatic hydrogen of cycloDOPA. - Synthesis of chiral N-trifluoroacetyl-methionine derivatives and applying them as acyl donors for Friedel-Crafts acylation
Kurokawa, Natsumi, Tokoro, Yurika, Tachrim, Zetryana Puteri, Wakasa, Haruna, Sakihama, Yasuko, Hashidoko, Yasuyuki, Hashimoto, Makoto
ARKIVOC, 42, 49, ARKAT USA INC, 2019, [Peer-reviewed]
English, Scientific journal, A chiral N-protected alpha-amino acid N-hydroxysuccinimide ester (OSu) is a common useful reagent for peptide bond formation. Recently, N-trifluoroacetyl (TFA) alpha-amino acid OSu esters have been reported as acyl donors for Frieldel-Crafts reactions to synthesize chiral alpha-amino phenyl ketones retaining the configurations of the starting alpha-amino acids. There are few reports for chiral TFA protected methionine, which has methylthioethyl structure in the side-chain of the alpha-amino acid. The detailed synthesis of chiral TFA-Met-OSu and its application as an acyl donor for Friedel-Crafts acylation is reported.[GRAPHICS]. - TFA-PROTECTED alpha-AMINO ACID N-HYDROXYSUCCINIMIDE ESTER: APPLICATION FOR INTER- AND INTRAMOLECULAR ACYLATION
Tachrim, Zetryana Puteri, Oida, Kazuhiro, Ohashi, Fumina, Wakasa, Haruna, Ikemoto, Haruka, Kurokawa, Natsumi, Sakihama, Yasuko, Hashidoko, Yasuyuki, Suzuki, Takeyuki, Hashimoto, Makoto
HETEROCYCLES, 97, 2, 877, 893, PERGAMON-ELSEVIER SCIENCE LTD, Sep. 2018, [Peer-reviewed]
English, Scientific journal, The utilization of N-trifluoroacetyl (TFA)-alpha-amino acid N-hydroxysuccinimide ester (OSu) derivatives, a promising acylating agent with high storage stability, is reported for Friedel Crafts acylation into arenes and N-heterocycles. The reaction between TFA-Phe-OSu derivatives and arenes afforded inter- and intramolecular products. TFA-Tyr-OSu derivatives, which possess hydroxyl substituent in the aromatic moiety of phenylalanine, afforded only intermolecular product with benzene. The heterocyclic TFA-Pro-OSu also shows relatively high reactivity toward acylation. - pH stability and antioxidant power of CycloDOPA and its derivatives
Shiori Nakagawa, Zetryana Puteri Tachrim, Natsumi Kurokawa, Fumina Ohashi, Yasuko Sakihama, Takeyuki Suzuki, Yasuyuki Hashidoko, Makoto Hashimoto
Molecules, 23, 8, 1943, 2018, [Peer-reviewed]
English, Scientific journal, © 2018 by the authors. CycloDOPA (leukodopachrome), a well known metabolite of tyrosine, is a precursor of melanine in mammalian organisms and of the pigment betalain in plants. However, the isolation of cycloDOPA from natural sources has not been widely reported. In the present work, the stabilities of cycloDOPA and cycloDOPA methyl ester at various pH levels were studied. Both compounds were stable under acidic conditions. By contrast, both compounds were unstable when the pH was shifted from neutral to basic to form indole derivatives as major products. Based on the pH stability, cycloDOPA and its derivatives were subjected to the DPPH radical scavenging assay for the first time. - Optimization of sucrose 1 '-position modification with 3-(trifluoromethyl)diazirinyl benzylbromide derivatives for photoaffinity labeling
Lei Wang, Zetryana Puteri Tachrim, Natsumi Kurokawa, Fumina Ohashi, Haruna Wakasa, Yasuko Sakihama, Yasuyuki Hashidoko, Takeyuki Suzuki, Makoto Hashimoto
ARKIVOC, 58, 65, ARKAT USA INC, 2018, [Peer-reviewed]
English, Scientific journal, Sucrose is well known as naturally occurring sweeteners. Photoreactive sucrose derivative containing 3-(trifluoromethyl)diazirinyl moiety is designed for photoaffinity labeling. As 1'-hydroxyl group of sucrose is well known to be less reactive than other primary alcohols, the optimization of reaction conditions for diazirinyl benzyl bromide derivative at sucrose 1'-portion was examined to elucidate the functional analysis of sweet receptors.[GRAPHICS]. - Application of Appel reaction to the primary alcohol groups of fructooligosaccharides: Synthesis of 6,6 ',6 ''-trihalogenated 1-kestose derivatives
Tachrim, Zetryana Puteri, Nakamura, Tadashi, Sakihama, Yasuko, Hashidoko, Yasuyuki, Hashimoto, Makoto
ARKIVOC, 341, 348, ARKAT USA INC, 2018, [Peer-reviewed]
English, Scientific journal, 1-kestose (O-B-D-fructofuranosyl-(2 -> 1)-B-D-fructofuranosyl-(2 -> 1)-alpha-D-glucopyranoside) is a potential short chain fructooligosaccharide with an inulin-type skeleton. Halogenation of 1-kestose was conducted via the Appel reaction with the use of carbon tetrahalide (CBr4 or CCI4) and triphenylphosphine, which was then followed by conventional acetylation. The per-O-acetylated form of 6,6',6 ''-trihalogenated derivatives of 1-kestose were conveniently isolated. Further deprotection of the per-O-acetylated form resulted in 6-, 6'-, and 6 ''-trihalogenated derivatives. The structure elucidation by one- and two-dimensional nuclear magnetic resonance established that halogenations are specific at the 6-, 6'-, and 6 ''-position of 1-kestose primary alcohols.[GRAPHICS]. - Activation of cryptic phthoxazolin A production in Streptomyces avermitilis by the disruption of autoregulator-receptor homologue AvaR3
Dian Anggraini Suroto, Shigeru Kitani, Kiyoko T. Miyamoto, Yasuko Sakihama, Masayoshi Arai, Haruo Ikeda, Takuya Nihira
JOURNAL OF BIOSCIENCE AND BIOENGINEERING, 124, 6, 611, 617, SOC BIOSCIENCE BIOENGINEERING JAPAN, Dec. 2017, [Peer-reviewed]
English, Scientific journal, The genomes of actinomycetes encode many cryptic novel/useful bioactive compounds, but access to these cryptic secondary metabolites remains limited. Streptomyces avermitilis predominantly produces three polyketide antibiotics (avermectin, filipin, and oligomycin) but has the potential to produce more secondary metabolites based on the number of cryptic biosynthetic gene clusters. Here, we extensively investigated the metabolite profiles of a gene disruptant of AvaR3 (an autoregulator receptor homologue), which is involved in the pleiotropic regulation of antibiotic production and cell morphology. Unlike the wild-type strain, the avaR3 mutant accumulated compound 3 in the culture. The chemical structure of compound 3 was elucidated on the basis of various spectroscopic analyses, and was identified as phthoxazolin A, a cellulose synthesis inhibitor. Bioassays demonstrated that compound 3 exerts growth inhibitory activity against a broad range of plant pathogenic oomycetes. Moreover, unlike avermectin production, phthoxazolin A (3) production was negatively controlled by avenolide, a new type of autoregulator in streptomycetes, through the function of AvaR3. These results suggest that the genetic manipulation of autoregulator receptor homologues would be a valuable tool for the discovery of cryptic bioactive compounds. (C) 2017, The Society for Biotechnology, Japan. All rights reserved. - Synthesis of Chiral TFA-Protected alpha-Amino Aryl-Ketone Derivatives with Friedel-Crafts Acylation of alpha-Amino Acid N-Hydroxysuccinimide Ester
Tachrim, Zetryana Puteri, Oida, Kazuhiro, Ikemoto, Haruka, Ohashi, Fumina, Kurokawa, Natsumi, Hayashi, Kento, Shikanai, Mami, Sakihama, Yasuko, Hashidoko, Yasuyuki, Hashimoto, Makoto
MOLECULES, 22, 10, MDPI AG, Oct. 2017, [Peer-reviewed]
English, Scientific journal, Chiral N-protected alpha-amino aryl-ketones are one of the useful precursors used in the synthesis of various biologically active compounds and can be constructed via Friedel-Crafts acylation of N-protected alpha-amino acids. One of the drawbacks of this reaction is the utilization of toxic, corrosive and moisture-sensitive acylating reagents. In peptide construction via amide bond formation, N-hydroxysuccinimide ester (OSu), which has high storage stability, can react rapidly with amino components and produces fewer side reactions, including racemization. This study reports the first synthesis and utilization of N-trifluoroacetyl (TFA)-protected alpha-amino acid-OSu as a potential acyl donor for Friedel-Crafts acylation into various arenes. The TFA-protected isoleucine derivative and its diastereomer TFA-protected allo-isoleucine derivative were investigated to check the retention of alpha-proton chirality in the Friedel-Crafts reaction. Further utilization of OSu in other branched-chain and unbranched-chain amino acids results in an adequate yield of TFA-protected alpha-amino aryl-ketone without loss of optical purity. - Base-Mediated One-Pot Synthesis of Aliphatic Diazirines for Photoaffinity Labeling
Lei Wang, Zetryana Puteri Tachrim, Natsumi Kurokawa, Fumina Ohashi, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
MOLECULES, 22, 8, MDPI AG, Aug. 2017, [Peer-reviewed]
English, Scientific journal, Aliphatic diazirines have been widely used as prominent photophores for photoaffinity labeling owing to their relatively small size which can reduce the steric effect on the natural interaction between ligands and proteins. Based on our continuous efforts to develop efficient methods for the synthesis of aliphatic diazirines, we present here a comprehensive study about base-mediated one-pot synthesis of aliphatic diazirines. It was found that potassium hydroxide (KOH) can also promote the construction of aliphatic diazirine with good efficiency. Importantly, KOH is cheaper, highly available, and easily handled and stored compared with the previously used base, potassium tert-butoxide (t-BuOK). Gram-scale study showed that it owned great advantages in being used for the large-scale production of aliphatic diazirines. This protocol is highly neat and the desired products can be easily isolated and purified. As the first comprehensive study of the base-mediated one-pot synthesis of aliphatic diazirines, this work provided good insight into the preparation and utilization of diazirine-based photoaffinity labeling probes. - SYNTHESIS OF PHOTOPHORE AND FLUOROPHORE MODIFIED O-BENZYLSERINE DERIVATIVES
Makoto Hashimoto, Takuma Yoshida, Zetryana Puteri Tachrim, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Yuichi Kanaoka
HETEROCYCLES, 95, 1, 462, 473, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2017, [Peer-reviewed]
English, Scientific journal, O-Benzylation of serine is one of the important protection methods for solid phase peptide synthesis. The utilities of the protection group may be indicated that chemical modifications for O-benzylserine will be utilized to make functional peptides on solid phase synthesis. Detailed studies for effective synthesis of photoreactive and fluorophore containing O-benzylserine derivatives without racemization were reported. - Comprehensive Synthesis of Photoreactive Phenylthiourea Derivatives for the Photoaffinity Labeling
Akiko Ishida, Lei Wang, Zetryana Puteri Tachrim, Takeyuki Suzuki, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
CHEMISTRYSELECT, 2, 1, 160, 164, WILEY-V C H VERLAG GMBH, Jan. 2017, [Peer-reviewed]
English, Scientific journal, Phenylthiourea (PTU) is well known as bioactive compound and one of the reversible inhibitors for tyrosinase. Tyrosinase plays very important roles for tyrosine metabolisms to maintain the skin homeostasis from sunlight with forming melanin. Synthesis of photoaffinity label reagents of PTU will be attractive thesis to elucidate functional analysis for tyrosinase. - Chemical Promotion of Endogenous Amounts of ABA in Arabidopsis thaliana by a Natural Product, Theobroxide
Yudai Yamashita, Maremichi Ota, Yutaka Inoue, Youko Hasebe, Masanori Okamoto, Tsuyoshi Inukai, Chikra Masuta, Yasuko Sakihama, Yasuyuki Hashidoko, Mikiko Kojima, Hitoshi Sakakibara, Yasuyuki Inage, Kosaku Takahashi, Teruhiko Yoshihara, Hideyuki Matsuura
PLANT AND CELL PHYSIOLOGY, 57, 5, 986, 999, OXFORD UNIV PRESS, May 2016, [Peer-reviewed]
English, Scientific journal, Plant hormones are a group of structurally diverse small compounds that orchestrate the cellular processes governing proper plant growth and environmental adaptation. To understand the details of hormonal activity, we must study not only their inherent activities but also the cross-talk among plant hormones. In addition to their use in agriculture, plant chemical activators, such as probenazole and uniconazole, have made great contributions to understand hormonal cross-talk. However, the use of plant chemical activators is limited due to the lack of activators for certain hormones. For example, to the best of our knowledge, there are only a few chemical activators previously known to stimulate the accumulation of ABA in plants, such as absinazoles and proanthocyanidins. In many cases, antagonistic effects have been examined in experiments using exogenously applied ABA, although these studies did not account for biologically relevant concentrations. In this report, it was found that a natural product, theobroxide, had potential as a plant chemical activator for stimulating the accumulation of ABA. Using theobroxide, the antagonistic effect of ABA against GAs was proved without exogenously applying ABA or using mutant plants. Our results suggest that ABA levels could be chemically controlled to elicit ABA-dependent biological phenomena. - Synthesis of Diazirine-Based Photoreactive Saccharin Derivatives for the Photoaffinity Labeling of Gustatory Receptors
Lei Wang, Takuma Yoshida, Yasuyuki Muto, Yuta Murai, Zetryana Puteri Tachrim, Akiko Ishida, Shiori Nakagawa, Yasuko Sakihama, Yasuyuki Hashidoko, Katsuyoshi Masuda, Yasumaru Hatanaka, Makoto Hashimoto
EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, 14, 3129, 3134, WILEY-V C H VERLAG GMBH, May 2015, [Peer-reviewed]
English, Scientific journal, Saccharin is one of the most common artificial sweeteners that has a bitter taste at high concentrations. Currently, there are no detailed functional analyses of these gustatory receptors. Therefore, we designed and synthesized photoreactive saccharin derivatives that contain a (trifluoromethyl) diazirinyl moiety at the 5- or 6-position for use as functional analysis tools for photoaffinity labeling. - Alternative One-Pot Synthesis of (Trifluoromethyl)phenyldiazirines from Tosyloxime Derivatives: Application for New Synthesis of Optically Pure Diazirinylphenylalanines for Photoaffinity Labeling
Lei Wang, Yuta Murai, Takuma Yoshida, Akiko Ishida, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
ORGANIC LETTERS, 17, 3, 616, 619, AMER CHEMICAL SOC, Feb. 2015, [Peer-reviewed]
English, Scientific journal, Alternative one-pot synthesis of 3-(trifluoromethyl)-3-phenyldiazirine derivatives from corresponding tosyloximes is developed. The deprotonation of intermediate diaziridine by NH2- is a new approach for construction of diazirine. Moreover, a novel synthesis of optically pure (trifluoromethyl)diazirinylphenylalanine derivatives was attempted involving these methods. - SYNTHESIS OF PHOTOREACTIVE DIAZIRINYL SALICIN DERIVATIVE TO ELUCIDATE FUNCTIONAL ANALYSIS OF THE BITTER TASTE RECEPTOR
Munenori Sakurai, Takuma Yoshida, Lei Wang, Yuta Murai, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
HETEROCYCLES, 90, 1, 698, 705, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2015, [Peer-reviewed]
English, Scientific journal, Salicin (salicyl alcohol glucoside) is a substance well known for its bitter taste. A photoreactive diazirinyl derivative of salicin will be utilized for the functional analysis of interactions between the bitter taste receptor and salicin. Glucosides of salicyl derivatives are more difficult than phenol derivatives that are unsubstituted at the ortho-position. A diazirinyl salicin derivative was synthesized at moderate yields by glucosidation of 2,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide and 2-hydroxy-4-[3-(trifluoromethyl)-3H-diazirin-3-yl]benzaldehyde in the presence of a phase-transfer catalyst, nBuEt(3)NBr, followed by reduction and deprotection. - Synthesis of Cross-linkable 2,5-Diketopiperazine Derivatives
Takuma Yoshida, Lei Wang, Shiori Nakagawa, Zetryana Puteri Tachrim, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
LETTERS IN ORGANIC CHEMISTRY, 12, 8, 544, 548, BENTHAM SCIENCE PUBL LTD, 2015, [Peer-reviewed]
English, Scientific journal, Synthesis of cross-linkable diketopiperadine derivatives is described. Cross-linkable a-amino acid methyl esters were subjected to peptide synthesis with Boc-protected glycine or L-tyrosine. No protection of cross-linkable functional groups (catechol and phenylazide) is necessary for the construction of diketopiperazine skeleton. - Hydrogen/deuterium exchange of cross-linkable alpha-amino acid derivatives in deuterated triflic acid
Lei Wang, Yuta Murai, Takuma Yoshida, Masashi Okamoto, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 78, 7, 1129, 1134, TAYLOR & FRANCIS LTD, Jul. 2014, [Peer-reviewed]
English, Scientific journal, In this paper we report here a hydrogen/deuterium exchange (H/D exchange) of cross-linkable alpha-amino acid derivatives with deuterated trifluoromethanesulfonic acid (TfOD). H/D exchange with TfOD was easily applied to o-catechol containing phenylalanine (DOPA) within an hour. A partial H/D exchange was observed for trifluoromethyldiazirinyl (TFMD) phenylalanine derivatives. N-Acetyl-protected natural aromatic alpha-amino acids (Tyr and Trp) were more effective in H/D exchange than unprotected ones. The N-acetylated TFMD phenylalanine derivative afforded slightly higher H/D exchange than unprotected derivatives. An effective post-deuteration method for cross-linkable alpha-amino acid derivatives will be useful for the analysis of biological functions of bioactive peptides and proteins by mass spectrometry. - Production of antioomycete compounds active against the phytopathogens Phytophthora sojae and Aphanomyces cochlioides by clavicipitoid entomopathogenic fungi
Sastia Prama Putri, Kei-ichi Ishido, Hiroshi Kinoshita, Shigeru Kitani, Fumio Ihara, Yasuko Sakihama, Yasuhiro Igarashi, Takuya Nihira
JOURNAL OF BIOSCIENCE AND BIOENGINEERING, 117, 5, 557, 562, SOC BIOSCIENCE BIOENGINEERING JAPAN, May 2014, [Peer-reviewed]
English, Scientific journal, A total of 412 strains belonging to 14 genera of clavicipitoid entomopathogenic fungi (EPF) were screened for activities against two economically important plant pathogenic oomycetes, Phytophthora sojae and Aphanomyces cochlioides. To identify the antioomycete compounds produced by EPF, the extracts of 13 highly active EPF strains were characterized in detail by high performance liquid chromatography with diode array detection and high-resolution mass spectrometric detection and antioomycete assay. The antioomycete activity of several Metarhizium extracts was associated with previously isolated aurovertins, fungerin, N-(methyl-3-oxodec-6-enoyl)-2-pyrroline, and N-(methyl-3-oxodecanoyl)-2-pyrroline. The depsipeptide beauvericin was confirmed to be one of the active principles of three strains of Isaria tenuipes, which strongly inhibited mycelial growth of both P. sojae and A. cochlioides. Two known bioactive metabolites, paecilosetin and aranorosinol A, together with a novel and potent antioomycete compound, farinomalein, were isolated from the extracts of Isaria farinosa and all compounds were confirmed to have antioomycete activity. Identification of 8 antioomycete compounds from 13 clavicipitioid EPF demonstrated a new potential use of EPF as a source of compounds for the control of soil-borne plant pathogenic oomycetes. (C) 2013, The Society for Biotechnology, Japan. All rights reserved. - 2,3-Bis(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenyl)oxirane
Lei Wang, Takuma Yoshida, Masashi Okamoto, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
MolBank, 2014, 1, M816, M816, MOLECULAR DIVERSITY PRESERVATION International （MDPI）, 24 Feb. 2014, [Peer-reviewed]
English, Scientific journal, The title compound, which has two photoreactive groups in a molecule, was synthesized by the coupling reaction of 3-(4-(bromomethyl)phenyl)-3-(trifluoromethyl)- 3H-diazirine in the presence of silver oxide in DMSO. © 2014 by the authors
licensee MDPI, Basel, Switzerland. - SYNTHESIS OF METHOXY-SUBSTITUTED DIAZIRINYL PHENYLALANINE -A NOVEL PHOTOREACTIVE ASPARTAME DERIVATIVE FOR FUNCTIONAL ANALYSIS OF SWEET RECEPTORS
Sakurai, Munenori, Masuda, Katsuyoshi, Wang, Lei, Murai, Yuta, Sakihama, Yasuko, Hashidoko, Yasuyuki, Hatanaka, Yasumaru, Hashimoto, Makoto
HETEROCYCLES, 88, 1, 629, 637, PERGAMON-ELSEVIER SCIENCE LTD, Jan. 2014, [Peer-reviewed]
English, Scientific journal, Photoreactive phenylalanine derivatives are well known as functional analysis reagents for target biomolecules. The photophores are commonly introduced at 4-position on benzene. Aspartame, which consists of dipeptide L-Asp-L-Phe-OMe, is one of the most utilized artificial sweeteners, and substitution effects on its benzene ring have been reported. Substitution at the 4-position, however, does not maintain its sweetness properties. Trifluoromethyldiazirine, which is one of the most reliable photophores, was introduced to a different site on phenylalanine and the new photoreactive phenylalanine was converted to aspartame derivatives. The new aspartame derivative had slightly higher sweetness potency than sucrose standard solution. - SIMPLE AND STEREOCONTROLLED PREPARATION OF BENZOYLATED PHENYLALANINE USING FRIEDEL - CRAFTS REACTION IN TRIFLUOROMETHANESULFONIC ACID FOR PHOTOAFFINITY LABELING
Yuta Murai, Lei Wang, Yasuyuki Muto, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
HETEROCYCLES, 87, 10, 2119, 2126, PERGAMON-ELSEVIER SCIENCE LTD, Oct. 2013, [Peer-reviewed]
English, Scientific journal, Simple and stereocontrolled preparation of benzoylated phenylalanine derivatives from optically pure phenylalanine using Friedel-Crafts reaction in trifluoromethanesulfonic acid (TfOH) is reported; these derivatives are useful for photoaffinity labeling. Protected or unprotected phenylalanine derivatives were converted to benzoyl derivatives in TfOH at room temperature in a short time without loss of optical purity. The reaction condition was applied to synthesize novel photoreactive phenylalanine derivative, which has two photophores (benzophenone and diazirine). The detail analysis of photo-irradiation for two different photophores contained phenylalanine derivative was also investigated. - Distinct Metabolites for Photoreactive L-Phenylalanine Derivatives in Klebsiella sp CK6 Isolated from Rhizosphere of a Wild Dipterocarp Sapling
Lei Wang, Wataru Hisano, Yuta Murai, Munenori Sakurai, Yasuyuki Muto, Haruka Ikemoto, Masashi Okamoto, Takashi Murotani, Reika Isoda, Dongyeop Kim, Yasuko Sakihama, Irnayuli R. Sitepu, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
MOLECULES, 18, 7, 8393, 8401, MDPI AG, Jul. 2013, [Peer-reviewed]
English, Scientific journal, Photoaffinity labeling is a reliable analytical method for biological functional analysis. Three major photophores-aryl azide, benzophenone and trifluoromethyldiazirine-are utilized in analysis. Photophore-bearing L-phenylalanine derivatives, which are used for biological functional analysis, were inoculated into a Klebsiella sp. isolated from the rhizosphere of a wild dipterocarp sapling in Central Kalimantan, Indonesia, under nitrogen-limiting conditions. The proportions of metabolites were quite distinct for each photophore. These results indicated that photophores affected substrate recognition in rhizobacterial metabolic pathways, and differential photoaffinity labeling could be achieved using different photophore-containing L-phenylalanine derivatives. - Effects of different classes of attractants, cochliophilin A and N-(E)-feruloy1-4-0-methyldopamine, on the response of Aphanomyces cochlioides zoospores in their chemoattraction and activation of motility linked with intracellular cAMP
Mengcen Wang, Tomohiko Takayama, Dongyeop Kim, Yasuko Sakihama, Satoshi Tahara, Yasuyuki Hashidoko
JOURNAL OF PESTICIDE SCIENCE, 38, 3-4, 181, 187, PESTICIDE SCI SOC JAPAN, 2013, [Peer-reviewed]
English, Scientific journal, Cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone, 1) and N-(E)-feruloy1-4-0-methyldopamine (2) are naturally occurring host-specific chemoattractants for Aphanomyces cochlioides zoospores. In a cross-competition assay, compound 1 (4 fmol) applied to diatomite particles clearly attracted A. cochlioides zoospores in an aqueous solution of excessive compound 2 (lx 10(-6)M) that could mask a concentration gradient of 1 dispersed from the particles. Similarly, 2 (40 fmol) on particles also attracted A. cochlioides zoospores in an aqueous solution of 1 (1 X 10(-6)M). In addition, compound 2 on the particles did not attract the zoospores in an aqueous solution containing 1 X10(-6)M NADP(+), while 1 clearly attracted zoospores in the same solution. These results allowed us to speculate that compounds 1 and 2 do not share receptors. The chemosensory system for 1 is probably for host recognition of A. cochlioides zoospores, while the system for 2 is linked to cell differentiation. (C) Pesticide Science Society of Japan - Rapid and controllable hydrogen/deuterium exchange on aromatic rings of α-amino acids and peptides
Yuta Murai, Lei Wang, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
European Journal of Organic Chemistry, 2013, 23, 5111, 5116, 2013, [Peer-reviewed]
English, Scientific journal, Novel hydrogen/deuterium exchange for aromatic α-amino acids and their corresponding peptides were performed through the use of deuterated trifluoromethanesulfonic acid (TfOD). Detailed analysis of the exchange revealed that equal hydrogen/deuterium exchange was observed for phenylalanine, and specific exchange at the ortho-positions of phenol for tyrosine was also detected. The stereochemistry of the aromatic α-amino acids was retained under the exchange conditions. The hydrogen/deuterium exchange properties for these aromatic α-amino acids are identical for peptides that contain several aromatic α-amino acids. The exchange proceeded significantly faster than previous methods. Detailed analysis of the exchange revealed that the method could be controlled by temperature, time, and the amount of reagent. Deuterated trifluoromethanesulfonic acid promotes rapid and controllable hydrogen/deuterium exchange on aromatic rings of α-amino acids and peptides at room temperature and below. The deuterium incorporation depends on the amount of reagent, the temperature, and the time-scale of the reaction. Copyright © 2013 WILEY-VCH Verlag GmbH &
Co. KGaA, Weinheim. - QUANTITATIVE ANALYSIS OF Cu(I) CONCENTRATION IN CLICK CHEMISTRY -BIOTINYLATION AT SIDE CHAIN OF PROPARGYLGLYCINE USING CLICK CHEMISTRY UNDER HEATING CONDITIONS-
Yui Ogasawara, Yuta Murai, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
HETEROCYCLES, 86, 1, 735, 743, PERGAMON-ELSEVIER SCIENCE LTD, Dec. 2012, [Peer-reviewed]
English, Scientific journal, The click reaction is one of the latest techniques for the chemical modification of bioactive compounds. Chemical modifications of alpha-amino acid side chains are gaining significance as useful and important tools for biochemical research. Biotinylation at side chain of propargylglycine using click reaction was examined. The detail quantitative analysis of Cu(I) concentration are performed to proceed the click reaction effectively. - Quantitative determination of click reaction in the presence of glycine derivatives and in dilute solution
Yui Ogasawara, Yuta Murai, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
International Journal of Organic Chemistry, 2, 3, 302, 304, Scientific Research Publishing, Inc., Nov. 2012, [Peer-reviewed]
English, Scientific journal - Effective Friedel-Crafts Acylation of Biotin Acid Chloride in Trifluoromethanesulfonic Acid
Yasuyuki Muto, Yuta Murai, Yasuko Sakihama, Yasuyuki Hashidoko, Makoto Hashimoto
BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 76, 11, 2162, 2164, TAYLOR & FRANCIS LTD, Nov. 2012, [Peer-reviewed]
English, Scientific journal, Biotin is one of the most useful tags in (bio)analytical science due to its specific interaction with avidin, but is not easy to convert because of its low solubility in most solvents. Friedel-Crafts acylation of biotin acid chloride in triflic acid was examined, and the synthesized derivatives had stronger affinity to avidin than biotin in a binding assay using 2-(4'-hydroxyphenylazo)benzoic acid. - Comprehensive Synthesis of Photoreactive (3-Trifluoromethyl)diazirinyl Indole Derivatives from 5- and 6-Trifluoroacetylindoles for Photoaffinity Labeling
Yuta Murai, Katsuyoshi Masuda, Yasuko Sakihama, Yasuyuki Hashidoko, Yasumaru Hatanaka, Makoto Hashimoto
JOURNAL OF ORGANIC CHEMISTRY, 77, 19, 8581, 8587, AMER CHEMICAL SOC, Oct. 2012, [Peer-reviewed]
English, Scientific journal, 5- and 6-trifluoromethyldiazirinyl indoles were synthesized from corresponding bromoindole derivatives for the first time. They acted as mother skeletons for the comprehensive synthesis of various bioactive indole metabolites. These can be used in biological functional analysis as diazirine-based photoaffinity labels. - Beetroot betalain inhibits peroxynitrite-mediated tyrosine nitration and DNA strand cleavage
Yasuko Sakihama, Makiko Maeda, Makoto Hashimoto, Satoshi Tahara, Yasuyuki Hashidoko
FREE RADICAL RESEARCH, 46, 1, 93, 99, INFORMA HEALTHCARE, Jan. 2012, [Peer-reviewed], [Lead author, Corresponding author]
English, Two major betalains, red-purple betacyanins and yellow betaxanthins, were isolated from red beetroots (Beta vulgaris L.), and their peroxynitrite (ONOO(-)) scavenging capacity was investigated. Apparent colours of the betalains were bleached by the addition of ONOO(-), and the absorbance decreases were suppressed in the presence of glutathione, a ONOO(-) scavenger. After bleaching, a new absorption maximum was observed at 350 nm in the spectrum of the resulting reaction mixture. New peaks were detected from HPLC analysis of the reaction products of betanin, a representative constituent of red beetroot betacyanins, treated with ONOO(-) monitoring at 350 nm, and the intensity of the major peak was positively correlated with ONOO(-) concentration. Betanin inhibited the ONOO(-) (0.5 mM)-dependent nitration of tyrosine (0.1 mM). Additionally, the IC(50) value of betanin (19.2 mu M) was lower than that of ascorbate (79.6 mu M). The presence of betanin (0.05-1.0 mM) also inhibited ONOO(-) (0.5 mM)-dependent DNA strand cleavage in a concentration -dependent manner. These results suggest that betalains can protect cells from nitrosative stress in addition to protecting them from oxidative stresses. - Composition of culture medium influences zoosporogenesis and differentiation of Aphanomyces cochlioides
Md. Tofazzal Islam, Mitsuyoshi Sakasai, Yasuyuki Hashidoko, Abhinandan Deora, Yasuko Sakihama, Satoshi Tahara
Journal of General Plant Pathology, 73, 5, 324, 329, Oct. 2007, [Peer-reviewed]
English, Scientific journal, A modified medium was used to culture mycelium and produce a large quantity of zoospores of Aphanomyces cochlioides, a principal pathogen of damping-off disease of sugar beet and root rot disease of spinach. The semisolid medium consisted of 17 g corn meal agar (CMA) added with 4 g of yeast extract (YE) per liter of 50 mM phosphate buffer (pH 6.8-7.0). This medium supported the production of ca. 106 zoospores ml-1 in 6-day-old cultures, approximately 11-fold higher than the commonly used CMA (17 g CMA per liter of water, pH 6.0 ± 0.2). Although morphological characters of the zoospores produced from the hyphae grown on CMA and CMA + YE were almost similar, they contrasted their developmental strategy after encystment induced by mechanical agitation. Cystospores originating from the zoospores on CMA regenerated zoospores (>
80%), while those from CMA + YE germinated (ca. 80%) and produced hyphae. Furthermore, 4-10% of the germinated cystospores on CMA + YE had double germ tubes. The soluble protein profiles of zoospores produced on CMA and on CMA + YE demonstrated that several proteins were either different or expressed differently. Our results suggest that the culture medium directly influences zoosporogenesis in A. cochlioides hyphae and the developmental strategy of the produced zoospores. © 2007 The Phytopathological Society of Japan and Springer. - Phytophthora genome sequences uncover evolutionary origins and mechanisms of pathogenesis
Brett M. Tyler, Sucheta Tripathy, Xuemin Zhang, Paramvir Dehal, Rays H. Y. Jiang, Andrea Aerts, Felipe D. Arredondo, Laura Baxter, Douda Bensasson, Jim L. Beynon, Jarrod Chapman, Cynthia M. B. Damasceno, Anne E. Dorrance, Daolong Dou, Allan W. Dickerman, Inna L. Dubchak, Matteo Garbelotto, Mark Gijzen, Stuart G. Gordon, Francine Govers, Niklaus J. Grunwald, Wayne Huang, Kelly L. Ivors, Richard W. Jones, Sophien Kamoun, Konstantinos Krampis, Kurt H. Lamour, Mi-Kyung Lee, W. Hayes McDonald, Monica Medina, Harold J. G. Meijer, Eric K. Nordberg, Donald J. Maclean, Manuel D. Ospina-Giraldo, Paul F. Morris, Vipaporn Phuntumart, Nicholas H. Putnam, Sam Rash, Jocelyn K. C. Rose, Yasuko Sakihama, Asaf A. Salamov, Alon Savidor, Chantel F. Scheuring, Brian M. Smith, Bruno W. S. Sobral, Astrid Terry, Trudy A. Torto-Alalibo, Joe Win, Zhanyou Xu, Hongbin Zhang, Igor V. Grigoriev, Daniel S. Rokhsar, Jeffrey L. Boore
SCIENCE, 313, 5791, 1261, 1266, AMER ASSOC ADVANCEMENT SCIENCE, Sep. 2006, [Peer-reviewed]
English, Scientific journal, Draft genome sequences have been determined for the soybean pathogen Phytophthora sojae and the sudden oak death pathogen Phytophthora ramorum. Oomycetes such as these Phytophthora species share the kingdom Stramenopila with photosynthetic algae such as diatoms, and the presence of many Phytophthora genes of probable phototroph origin supports a photosynthetic ancestry for the stramenopiles. Comparison of the two species' genomes reveals a rapid expansion and diversification of many protein families associated with plant infection such as hydrolases, ABC transporters, protein toxins, proteinase inhibitors, and, in particular, a superfamily of 700 proteins with similarity to known oomycete avirulence genes. - Heterologous expression of a pleiotropic drug resistance transporter from Phytophthora sojae in yeast transporter mutants
MS Connolly, Y Sakihama, Phuntumart, V, YJ Jiang, F Warren, L Mourant, PF Morris
CURRENT GENETICS, 48, 6, 356, 365, SPRINGER, Dec. 2005, [Peer-reviewed]
English, Scientific journal, A system for the expression of an ATP binding cassette (ABC) transporter from the soybean pathogen Phytophthora sojae is described. Pdr1, an ABC transporter with homology to the pleiotropic drug resistance (PDR) family of transporters, was cloned by primer walking from a P. sojae genomic library. Reverse transcriptase PCR assays showed that the transcript disappeared after encystment of zoospores and was not detected in hyphal germlings in dilute salts, in hyphae growing in liquid V8 media, or in tissue extracts from infected hypocotyls. BLAST analysis of Pdr1 against the P. sojae EST database also revealed that this gene was present only in zoospore libraries. Comparison of the number of hits to Pdr1 with that of a set of housekeeping genes revealed that Pdr1 was expressed at rates two- to threefold higher than other transcripts. To test the hypothesis that Pdr1p functions as a broad substrate membrane transporter, Pdr1 was transformed into yeast mutants deficient in several drug resistance transporters. Yeast mutants transformed with Pdr1 possessed partial drug resistance against only 5 of 17 chemically distinct compounds. Thus, when expressed in yeast, this transporter has a significantly narrower substrate specificity in comparison to the yeast transporters, Pdr5p, Yorlp, and Snq2p. - A photoaffinity probe designed for host-specific signal flavonoid receptors in phytopathogenic Peronosporomycete zoospores of Aphanomyces cochlioides
Y Sakihama, T Shimai, M Sakasai, T Ito, Y Fukushi, Y Hashidoko, S Tahara
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 432, 2, 145, 151, ELSEVIER SCIENCE INC, Dec. 2004, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal, Aphanomyces cochlioides zoospores show chemotaxis to cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone, 1), a host derived attractant, and also respond to 5,7-dihydroxyflavone (2) known as an equivalent chemoattractant. To investigate the chernotactic receptors in the zoospores, we designed photoaffinity probes 4'-azido-5,7-dihydroxyflavone (3) and 4'-azido-7-O-biotinyl-5hydroxyflavone (4) considering chemical structure of 2. Both 3 and 4 had zoospore attractant activity which was competitive with that of 1. When zoospores were treated with the biotinylated photoaffinity probe followed by UV irradiation and streptavidin-gold or peroxidase-conjugated streptavidin, probe-labeled proteins were detected on the cell membrane. This result indicated that the 1-specific-binding proteins, a candidate for hypothetical cochliophilin A receptor, were localized on the cell membrane of the zoospores. This is the first experimental evidence of flavonoid-binding proteins being present in zoospores, using chemically synthesized azidoflavone as photoaflinity-labeling reagent. (C) 2004 Elsevier Inc. All rights reserved. - Formation and degradation of plant nitro-phenolic compounds
Yasuko Sakihama
Nitric Oxide-biology and Chemistry, 2004
Scientific journal - Enzymatic nitration of phytophenolics: evidence for peroxynitrite-independent nitration of plant secondary metabolites
Y Sakihama, R Tamaki, H Shimoji, T Ichiba, Y Fukushi, S Tahara, H Yamasaki
FEBS LETTERS, 553, 3, 377, 380, ELSEVIER SCIENCE BV, Oct. 2003, [Peer-reviewed], [Lead author]
English, Scientific journal, Peroxynitrite (ONOO-), a reactive nitrogen species, is capable of nitrating tyrosine residue of proteins. Here we show in vitro evidence that plant phenolic compounds can also be nitrated by an ONOO--independent mechanism. In the presence of NaNO2, H2O2, and horseradish peroxidase (HRP), monophenolic p-coumaric acid (p-CA, 4-hydroxycinnamic acid) was nitrated to form 4-hydroxy-3-nitrocinnamic acid. The reaction was completely inhibited by KCN, an inhibitor for HRP. The antioxidant ascorbate suppressed p-CA nitration and its suppression time depended strongly on ascorbate concentration. We conclude that nitrogen dioxide radical (NO2), but not ONOO-, produced by a guaiacol peroxidase is the intermediate for phytophenolic nitration. (C) 2003 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies. - Involvement of nitric oxide in the mechanism for stomatal opening in Vicia faba leaves
Y Sakihama, S Murakami, H Yamasaki
BIOLOGIA PLANTARUM, 46, 1, 117, 119, KLUWER ACADEMIC PUBL, 2003, [Peer-reviewed], [Lead author]
English, Scientific journal, Nitrite, as well as the nitric oxide (NO) donor S-nitroso-N-acethylpenisilamine (SNAP), was found to increase the aperture of stoma on Vicia faba leaf peels. The results demonstrated here suggest that the nitrite-dependent NO production pathway would be involved in the signal transduction for stomatal movements. - Synergistic effect of deoxyanthocyanins from symbiotic fern Azolla spp. on hrmA gene induction in the cyanobacterium Nostoc punctiforme
Michael F. Cohen, Yasuko Sakihama, Yojiro C. Takagi, Toshio Ichiba, Hideo Yamasaki
Molecular Plant-Microbe Interactions, 15, 9, 875, 882, American Phytopathological Society, 01 Sep. 2002, [Peer-reviewed]
English, Scientific journal, The hrmA gene of the N2-fixing cyanobacterium Nostoc punctiforme functions in repressing the formation of transitory motile filaments, termed hormogonia, by plant-associated vegetative filaments. Here, we report that anthocyanins can contribute to induction of hrmA expression. Aqueous extract from fronds of the fern Azolla pinnata, a host of symbiotic Nostoc spp., was found to be a potent inducer of hrmA-luxAB in N. punctiforme strain UCD 328. The hrmA-luxAB inducing activities of A. pinnata, as well as Azolla filiculoides, were positively correlated with levels of frond deoxyanthocyanins. Analyses of the deoxyanthocyanins in frond extracts revealed, in order of predominance, an acetylated glycoside derivative of luteolinidin (m/z 475) and of apigeninidin (m/z 459) and minor amounts of a second luteolinidin derivative. At up to 150 μM, a purified preparation of deoxyanthocyanins only weakly induced hrmA-luxAB on its own, but mixtures with hrmA-luxAB inducers (A. filiculoides extract or the flavonoid naringin) synergistically doubled to tripled their inducing activities. These results suggest that appropriately localized deoxyanthocyanins could function in plant-mediated mechanisms for repressing Nostoc spp. hormogonium formation. - Plant phenolic antioxidant and prooxidant activities: phenolics-induced oxidative damage mediated by metals in plants
Y Sakihama, MF Cohen, SC Grace, H Yamasaki
TOXICOLOGY, 177, 1, 67, 80, ELSEVIER IRELAND LTD, Aug. 2002, [Peer-reviewed], [Lead author]
English, Scientific journal, Plant phenolic compounds such as flavonoids and lignin precursors are important constituents of the human diet. These dietary phytophenolics have been recognized largely as beneficial antioxidants that can scavenge harmful active oxygen species including O(2)(.-), H(2)O(2), (.)OH, and (1)O(2). Here we review our current understanding of the antioxidant and prooxidant actions of phenolics in plant cells. In plant systems, phytophenolics can act as antioxidants by donating electrons to guaiacol-type peroxidases (GuPXs) for the detoxification of H(2)O(2) produced under stress conditions. As a result of such enzymatic as well as non-enzymatic antioxidant reactions, phenoxyl radicals are formed as the primary oxidized products. Until recently, phenoxyl radicals had been difficult to detect by static electron spin resonance (ESR) because they rapidly change to non-radical products. Application of Zn exerts spin-stabilizing effects on phenoxyl radicals that enables us to analyze the formation and decay kinetics of the radicals. The ESR signals of phenoxyl radicals are eliminated by monodehydroascorbate radical (MDA) reductase, suggesting that phenoxyl radicals, like the ascorbate radical, are enzymatically recycled to parent phenolics. Thus, phenolics in plant cells can form an antioxidant system equivalent to that of ascorbate. In contrast to their antioxidant activity, phytophenolics also have the potential to act as prooxidants under certain conditions. For example, flavonoids and dihydroxycinnamic acids can nick DNA via the production of radicals in the presence of Cu and O(2). Phenoxyl radicals can also initiate lipid peroxidation. Recently, Al, Zn, Ca, Mg and Cd have been found to stimulate phenoxyl radical-induced lipid peroxidation. We discuss the mechanism of phenoxyl radical prooxidant activity in terms of lifetime prolongation by spin-stabilizing agents. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved. - High susceptibility of photoinhibition of photosynthesis in the tropical fig tree Ficus microcarpa L. cv. Golden Leaves
Takahashi S, Tamashiro A, Sakihama Y, Yamamoto Y, Kawamitsu Y, Yamasaki H
BMC Plant Biology, 2, 2, 1471, 2229, その他の出版社, 02 Apr. 2002, [Peer-reviewed]
English, Scientific journal, The tropical plant <i>Ficus microcarpa</i> L. f. cv. Golden Leaves (GL) is a high-light sensitive tropical fig tree in which sun-leaves are yellow and shade-leaves are green. We compared the response of photosynthetic activities to strong light between GL and its wild-type (WT, <i>Ficus microcarpa</i> L. f.). Field measurements of maximum photosystem II (PSII) efficiency (Fv/Fm) of intact sun-leaves in GL showed that photo synthetic activity was severely photoinhibited during the daytime (Fv/Fm = 0.46) and subsequently recovered in the evening (Fv/Fm = 0.76). In contrast, WT did not show any substantial changes of Fv/Fm values throughout the day (between 0.82 and 0.78). Light dependency of the CO<sub>2</sub> assimilation rate in detached shade-leaves of GL showed a response similar to that in WT, suggesting no substantial difference in photosynthetic performance between them. Several indicators of photoinhibition, including declines in PSII reaction center protein (D1) content, Fv/Fm value, and O<sub>2</sub> evolution and CO<sub>2</sub> assimilation rates, all indicated that GL is much more susceptible to photoinhibition than WT. Kinetics of PAM chlorophyll a fluorescence revealed - Nitric oxide production mediated by nitrate reductase in the green alga Chlamydomonas reinhardtii: an alternative NO production pathway in photosynthetic organisms
Y Sakihama, S Nakamura, H Yamasaki
PLANT AND CELL PHYSIOLOGY, 43, 3, 290, 297, OXFORD UNIV PRESS, Mar. 2002, [Peer-reviewed], [Lead author]
English, Scientific journal, Biological activity of nitric oxide (NO) production was investigated in the unicellular green alga Chlamydomonas reinhardtii. An NO specific electrode detected a rapid increase in signal when nitrite (NO(2)(-)) was added into a suspension of C. reinhardtii intact cells in the dark. The addition of KCN or the NO quencher bovine hemoglobin completely abolished the signal, verifying that the nitrite-dependent increase in signal is due to enzymatic NO production. L-arginine, the substrate for NO synthase, did not induce detectable NO production and the NOS inhibitor N(omega)-vitro-L-arginine showed no inhibitory effect on the nitrite-dependent production of NO. Illuminating cells showed a significant suppressive effect on NO production. When the photosynthetic electron transport inhibitor 3(3,4-dichlorophenyl)-1,1-dimethylurea was present in the suspension, C. reinhardtii cells produced NO after the addition of nitrite even under illumination. Kinetic and microscopic observations, using the intracellular fluorescent NO probe 4,5-diaminofluorescein-2 diacetate, both demonstrated that NO was produced within the cells in response to the addition of nitrite. The Chlamydomonas mutant cc-2929, which lacks nitrate reductase (NR) activity, did not display any of the responses observed in the wild-type cells. The results presented here provide direct in vivo evidence to confirm that NR is involved in the nitrite-dependent NO production in the green alga. - Molecular phylogenetic analyses of reverse-transcribed bacterial rRNA obtained from deep-sea cold seep sediments
Yasuko Sakihama
Environmental Microbiology, 2002
Scientific journal - Profile of microbial community structure and presence of endolithic microorganisms inside a deep-sea rock
Yasuko Sakihama
Geomicrobiology Journal, 2002
Scientific journal - Separation of highly fluorescent proteins by SDS-PAGE in Acroporidae corals
M. Papina, Y. Sakihama, C. Bena, R. Van Woesik, H. Yamasaki
Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology, 131, 4, 767, 774, 2002, [Peer-reviewed]
English, Scientific journal, This study characterized the spectral properties of Acropora tenuis, A. nasuta, A. secale, and A. aspera, all of which showed strong colorful fluorescence under ultraviolet light-A (black light). The emission maxima of fluorescence from the intact corals were 517, 482, 484, and 514 nm in A. tenuis, A. nasuta, A. secale, and A. aspera, respectively. Using a soluble fraction of cell-free extract of the corals, we applied a method of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) to separate each fluorescent protein component contained in the corals. Green fluorescent bands were detected in all Acropora examined, although their apparent molecular mass and relative content were different. A. aspera had two orange bands in addition to the green one. The major excitation and emission peaks of the orange fluorescence bands were almost identical (476 and 478 nm), however, they were discernible by their spectral profiles and molecular masses. Some biochemical properties of the highly fluorescent proteins of Acropora are described and implications of the results are discussed. © 2002 Elsevier Science Inc. All rights reserved. - Lipid peroxidation induced by phenolics in conjunction with aluminum ions
Y Sakihama, H Yamasaki
BIOLOGIA PLANTARUM, 45, 2, 249, 254, KLUWER ACADEMIC PUBL, 2002, [Peer-reviewed]
English, Scientific journal, Using the whole plant and model systems, we demonstrate that the aluminum ions (Al3+) stimulate phenolic-dependent lipid peroxidation, Lipid peroxidation in barley (Hordeum vulgare L. cv. Donor) roots was 30% higher under AlCl3 treatment than without Al, Major decomposition product of lipid peroxidation was 4-hydroxynonenal (4-HNE) but not thiobarbituric acid reactive substances (TBARS), a widely used markers for lipid peroxidation. Similarly, AlCl3 stimulated lipid peroxidation of soybean liposomes in the presence of chlorogenic acid (CGA) and H2O2/horseradish peroxidase system which can oxidize phenolics. Al3+ was found to enhance lipid peroxidation induced by oxidized CGA. Intermediates of lignin biosynthesis in plants, including p-coumaric acid, ferulic acid, sinapic acid and coniferyl alcohol, also showed similar effects. These results suggest that Al3+ has a potential to induce oxidative stress in plants by stimulating the prooxidant nature of endogenous phenolic compounds. - Inhibitory effects of nitric oxide on oxidative phosphorylation in plant mitochondria
H Yamasaki, H Shimoji, Y Ohshiro, Y Sakihama
NITRIC OXIDE-BIOLOGY AND CHEMISTRY, 5, 3, 261, 270, ACADEMIC PRESS INC, Jun. 2001, [Peer-reviewed], [Last author]
English, Scientific journal, Plant nitrate reductase (NR) produces nitric oxide (NO) when nitrite is provided as the substrate in the presence of NADH [H. Yamasaki and Y. Sakihama (2000) FEBS Lett. 468, 89-92]. Using a NR-dependent NO producing system, we investigated the effects of NO on the energy transduction system in plant mitochondria isolated from mung bean (Vigna radiata). Plant mitochondria are known to possess two respiratory electron transport pathways-the cytochrome and alternative pathways. When the alternative pathway was inhibited by n-propyl gallate, the addition of NR strongly suppressed respiratory O-2 consumption driven by the cytochrome pathway. In contrast, the alternative pathway measured in the presence of antimycin A was not affected by NO. The extent of the steady-state membrane potential (Delta psi) generated by respiratory electron transport rapidly declined in response to NO production. The addition of bovine hemoglobin, a quencher of NO, resulted in the recovery of Delta psi to the uninhibited level. Consistent with its inhibition of Delta psi, NO produced by NR strongly suppressed ATP synthesis in the mitochondria. These results provide substantial evidence to confirm that the plant alternative pathway is resistant to NO and support the idea that the alternative pathway may lower respiration-dependent production of active oxygens under conditions where NO is overproduced, (C) 2001 Academic Press - Reduction of phenoxyl radicals mediated by monodehydroascorbate reductase
Y Sakihama, J Mano, S Sano, K Asada, H Yamasaki
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 279, 3, 949, 954, ACADEMIC PRESS INC, Dec. 2000, [Peer-reviewed], [Lead author]
English, Scientific journal, Monodehydroascorbate (MDA) reductase catalyzes the reduction of MDA, the only organic radical substrate for the enzyme reported so far. Here, we show that cucumber MDA reductase is also capable of reducing phenoxyl radicals which are generated by horseradish peroxidase (HRP) with H2O2. The addition of MDA reductase plus NADH suppressed the HRP/H2O2-dependent oxidation of quercetin, accompanied by the oxidation of NADH, The quenching of the quercetin radical by MDA reductase plus NADH was confirmed by ESR. MDA reductase with NADH also suppressed the HRP/H2O2-dependent oxidation of hydroxycinnamates, including ferulic acid, coniferyl alcohol, and chlorogenic acid. Thus, the phenoxyl radicals of plant phenols can be reduced to their respective parent phenols by MDA reductase via a mechanism similar to the reduction of MDA. (C) 2000 Academic Press. - Simultaneous production of nitric oxide and peroxynitrite by plant nitrate reductase: in vitro evidence for the NR-dependent formation of active nitrogen species
H Yamasaki, Y Sakihama
FEBS LETTERS, 468, 1, 89, 92, ELSEVIER SCIENCE BV, Feb. 2000, [Peer-reviewed], [Last author]
English, Scientific journal, We examined the ability of plant nitrate reductase (NR) to produce nitric oxide (NO) using in vitro assays. Electrochemical and fluorometric measurements both showed that NO is produced by corn NR in the presence of nitrite and NADH at pH 7. The NO production was inhibited by sodium azide, a known inhibitor for NR. During the reaction, absorbance of 2',7'-dichlorodihydrofluorescein increased markedly. This change was completely suppressed by sodium azide, glutathione or depletion of oxygen. We conclude that plant NR produces both NO and its toxic derivative, peroxynitrite, under aerobic conditions when nitrite is provided as the substrate for NR, (C) 2000 Federation of European Biochemical Societies. - An alternative pathway for nitric oxide production in plants: new features of an old enzyme
H Yamasaki, Y Sakihama, S Takahashi
TRENDS IN PLANT SCIENCE, 4, 4, 128, 129, ELSEVIER SCIENCE LONDON, Apr. 1999, [Peer-reviewed]
English, Scientific journal - Flavonoid-peroxidase reaction as a detoxification mechanism of plant cells against H2O2
H Yamasaki, Y Sakihama, N Ikehara
PLANT PHYSIOLOGY, 115, 4, 1405, 1412, AMER SOC PLANT PHYSIOLOGISTS, Dec. 1997, [Peer-reviewed]
English, Scientific journal, Recent studies have revealed that dietary flavonoids are potent radical scavengers, acting in a manner similar to ascorbate and alpha-tocopherol. However, it is still not clear whether flavonoids have a similar antioxidative function in plants. We examined the possibility that flavonoids could function as stress protectants in plant cells by scavenging H2O2. Two major flavonoids, quercetin and kaempferol glycosides, were isolated from leaves of the tropical tree Schefflera arboricola Hayata. Both glycosides and aglycones of isolated flavonols were oxidized by H2O2 in the presence of horseradish peroxidase and/or in a soluble fraction of S. arboricola leaf extract. The rates of oxidation were in the order quercetin > kaempferol > quercetin glycoside >> kaempferol glycoside. Judging from the effects of inhibitors such as KCN, p-chloromercuribenzoate, and 3-amino-1H-1,2,4-triazole, we conclude that guaiacol peroxidase in the soluble fraction catalyzes H2O2-dependent oxidation of flavonols. In the flavonol-guaiacol peroxidase reaction, ascorbate had the potential to regenerate flavonols by reducing the oxidized product. These results provide further evidence that the flavonoid-peroxidase reaction can function as a mechanism for H2O2 scavenging in plants. - Bleaching of the red anthocyanin induced by superoxide radical
H Yamasaki, H Uefuji, Y Sakihama
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 332, 1, 183, 186, ACADEMIC PRESS INC JNL-COMP SUBSCRIPTIONS, Aug. 1996, [Peer-reviewed], [Last author]
English, Scientific journal, Red anthocyanin prepared from petals of Hibiscus rosa-sinensis L. was photobleached in the EDTA-riboflavin system. The rate of bleaching monitored at 565 nm depended on the light intensity and EDTA concentrations. Anaerobic conditions and/or addition of superoxide dismutase prevented the bleaching of anthocyanin, whereas mannitol and catalase did not, A similar bleaching was observed under dark conditions in the xanthine-xanthine oxidase system. The results indicate that anthocyanin is bleached by the nonenzymatic reaction with the superoxide radical and suggest that the pigment can function as an antioxidant. The antioxidative efficiency of cyanidin to superoxide was 10-fold higher than that of cyanidin-3-sophoroside as a Hibiscus anthocyanin. (C) 1996 Academic Press, Inc. - Isolation of flavonol glycosides from leaves of the tropical plant Schefflera arboricola HayataF
Sakihama Y, Ikehara N, Yamasaki H
The biological magazine Okinawa, 33, 43, 48, Mar. 1995, [Peer-reviewed], [Lead author]
Japanese, Scientific journal, Two flavonol gylcosides were isolated from the fresh leaves of the tropical tree <i>Schefflera arboricola</i> Hayata. The major flavonol glycosides of <i>S. arboricola</i> were identified to be quercetin and kaempferol glycosides on the basis of thin layer chromatogram and absorption spectral data. The absorption coefficients of these glycosides were estimated to be 14.7 mM<sup>-1</sup>cm<sup>-1</sup> at A<sub>358</sub> (the quercetin glycoside) and 16.0 mM<sup>-1</sup>cm<sup>-1</sup> at A<sub>346</sub> (the kaempferol glycoside).
Other Activities and Achievements
- Analysis of gene expression associated with morphological changes in the phytopathogenic oomycete Aphanomyces cochlioides zoospore
竹原由希子, 佐藤優樹, 橋本誠, 崎浜靖子, 日本農芸化学会大会講演要旨集(Web), 18 Mar. 2022, [Corresponding author]
Summary national conference - Phytochemical Antioxidants: Past, Present and Future
Yasuko Sakihama, Hideo Yamasaki, Antioxidants [Working Title], 13 Jan. 2021, [Peer-reviewed], [Lead author]
Most diseases that are difficult to prevent and cure are “syndromes” that are governed by multiple components with complicated interactions. Whatever the cause of such diseases, overproduction of harmful reactive oxygen species (ROS) can often be observed in progression of the disease. Under such conditions, the cells may be challenged by “oxidative stress” due to excessively generated oxidants. Antioxidants can be defined as chemical compounds that scavenge ROS or free radicals over-produced in the cells under oxidative stress conditions. The plant pigments flavonoids and betalains, rich in fruits and vegetables, are reactive not only with ROS but also with reactive nitrogen species (RNS) and possibly with reactive sulfur species (RSS). Here, we provide an overview of updates on the antioxidative functions of the plant pigments along with some prospects for future research on phytochemical antioxidants., IntechOpen, Introduction other - Betanin, a plant pigment from red beetroot, protects from peroxynitrite-induced oxidative and/or nitrosative stress in mammalian cells
加藤嵩士, 薬師葉, 橋本誠, 橋床泰之, 崎浜靖子, 日本農芸化学会大会講演要旨集(Web), 2020, ROMBUNNO.3A04p02 (WEB ONLY), 06 Mar. 2020, [Corresponding author]
Summary national conference - 植物色素betaninの活性酸素種・活性窒素種に対する細胞保護機能に関する研究
加藤嵩士,浅野純一,Duan Jie,薬師 葉,橋本 誠,橋床泰之,崎浜靖子, 第72回日本酸化ストレス学会学術集会, Jun. 2019, [Corresponding author]
Summary national conference - cycloDOPA誘導体のpH安定性とその抗酸化能
中川詩織, TACHRIM Zetryana Puteri, 崎浜靖子, 橋床泰之, 橋本誠, 日本農芸化学会東北支部大会プログラム・講演要旨集, 153rd, 84, 22 Sep. 2018
Japanese - 植物病原性卵菌Aphanomyces cochlioidesの宿主感染時形態変化及び遺伝子発現動態解析
佐藤優樹, 橋本誠, 橋床泰之, 崎浜靖子, 日本農芸化学会東北支部大会プログラム・講演要旨集, 153rd, 48, 22 Sep. 2018
Japanese - 植物色素ベタレイン―分布，生合成および生理機能~謎に包まれた多機能性植物色素~
崎浜 靖子, 化学と生物, 55, 582, 584, Aug. 2017, [Invited] - 安定同位体標識光反応性芳香族アミノ酸誘導体の合成
橋本誠, WANG Lei, 崎浜靖子, 橋床泰之, 日本農芸化学会大会講演要旨集(Web), 2017, ROMBUNNO.3C14a05 (WEB ONLY), 05 Mar. 2017
Japanese - 高温環境下におけるスイスチャードのカラータイプ間の異なるストレス応答
林寛容, 花井悠介, 橋本誠, 橋床泰之, 崎浜靖子, 日本植物学会大会研究発表記録, 80th, 168, 01 Sep. 2016
Japanese - 植物色素ベタレインによる活性窒素依存性脂質過酸化反応及びタンパク質ニトロ化反応の抑制
林寛容, 布施茜, 羽馬大輔, 橋本誠, 橋床泰之, 崎浜靖子, 日本農芸化学会大会講演要旨集(Web), 2016, 2H053 (WEB ONLY), 05 Mar. 2016
Japanese - An Overview of Methods in Plant Nitric Oxide (NO) Research: Why Do We Always Need to Use Multiple Methods?
Yasuko Sakihama, Methods in Molecular Biology, 1424, 1, 14, 2016, [Peer-reviewed], [Invited]
English - S07 Functions of jasmonates in potato tuberization
Inoue Yutaka, Shimizu Takafumi, Takahashi Kosaku, Sakihama Yasuko, Seo Mitsunori, Matsuura Hideyuki, 植物化学調節学会研究発表記録集, 50, 29, 29, 01 Oct. 2015
The Japanese Society for Chemical Regulation of Plants, Japanese - ベタレイン含有植物における環境ストレス負荷によるタンパク質の変動
花井悠介, 布施茜, 橋床泰之, 橋本誠, 崎浜靖子, 日本植物学会大会研究発表記録, 79th, 209, 01 Sep. 2015
Japanese - 植物タンパク質機能に対するニトロ化修飾の影響
花井悠介, 植木達也, 橋床泰之, 崎浜靖子, 日本農芸化学会大会講演要旨集(Web), 2015, 3D23A05 (WEB ONLY), 05 Mar. 2015
Japanese - ベタレイン色素の活性窒素消去機構におけるイミン構造の役割とベタラミン酸の反応性
大井辰哉, 前田麻起子, 崎浜靖子, 橋本誠, 橋床泰之, 日本農芸化学会北海道支部講演会講演要旨, 2012, 33, 01 Nov. 2012
Japanese - 非生物的ストレス負荷によるヒユ科植物のタンパク質ニトロ化
植木達也, 橋床泰之, 崎浜靖子, 日本農芸化学会大会講演要旨集(Web), 2012, 2A30A09 (WEB ONLY), 05 Mar. 2012
Japanese - ベタレイン色素の活性窒素種消去機構の解明とベタレイン色素中のイミンの役割
大井辰哉, 前田麻起子, 崎浜靖子, 橋本誠, 橋床泰之, 日本農芸化学会大会講演要旨集(Web), 2012, 3A05A15 (WEB ONLY), 05 Mar. 2012
Japanese - ダイズ茎疫病菌Phytophthora sojae遊走子の感染時形態変化に関わる遺伝子の探索
木谷祐也, 崎浜靖子, 橋床泰之, 日本農芸化学会大会講演要旨集(Web), 2012, 4C24A13 (WEB ONLY), 05 Mar. 2012
Japanese - 赤かび病菌のマイコトキシン産生に対する含硫アミノ酸の影響
山口晃, 小山知朗, 崎浜靖子, 橋床泰之, 福士幸治, 日本農芸化学会大会講演要旨集, 2011, 29, 05 Mar. 2011
Japanese - モデル化合物として5‐hydroxyindole‐2‐carboxylic acidを用いたbetalain色素による活性窒素種消去能の検討
大井辰哉, 前田麻起子, 崎浜靖子, 橋本誠, 橋床泰之, 日本農芸化学会大会講演要旨集, 2011, 25, 05 Mar. 2011
Japanese - A205 Search for chemical factor that is contained in soybean crude refuse and enhances production of antifungal cyclic peptides by Bacillus amyloliquefaciens.
Hashidoko Yasuyuki, Sonoda Sumihiro, Sugita Hojun, Sakihama Yasuko, 講演要旨集, 36, 49, 49, 25 Feb. 2011
Pesticide Science Society of Japan, Japanese - ソテツとNostoc sp.の共生によるソテツ・サンゴ状根形成に関わるシグナル物質の検索
田中慎人, 崎浜靖子, 橋床泰之, 植物の生長調節, 45, Supplement, 55, 01 Oct. 2010
Japanese - 2B12 Purification, isolation and structural analysis of the 2 groups of antifungal peptides produced by Bacillus amyloliquefaciens from root of Chinese cabbage.
Sonoda Sumihiro, Sugita Hojun, Sakihama Yasuko, Hashidoko Yasuyuki, 講演要旨集, 35, 65, 65, 21 Apr. 2010
Pesticide Science Society of Japan, Japanese - 植物病原性卵菌Aphanomyces cochlioides遊走子のcochliophilin Aレセプター候補タンパク質遺伝子の取得と酵母での発現の試み
田中誠一, 崎浜靖子, 福士幸治, 田原哲士, 橋床泰之, 日本農芸化学会大会講演要旨集, 2010, 221, 05 Mar. 2010
Japanese - 38. Search for signal substances that are associated with coralloid root formation as an event in cycad-cyanobacteria symbiosis
Tanaka Manato, Sakihama Yasuko, Hashidoko Yasuyuki, The Janapese Society for Chemical Regulation of Plants, Abstract, 45, 0, 55, 55, 2010
Background) Nostoc sp., a cyanobacterium establishes symbiosis with cycad (Cycus revolute) root. Nostoc sp. firstly recognizes the host plant root, next moves to the root tip, and eventually induces the coralloid root. Generally Nostoc sp. does not possess motility, but it differentiates to hormogonia, a motile form. Hypothetically, cycad root releases hormogonia-inducing factor (HIF) to establish the symbiosis between them. In this research, we screened HIF-like principle from the coralloid roots. Materials and Method) The coralloid roots collected at Yaku Island in late March, 2009 (1.08kg), and at Tanegashima Island, in early May, 2010 (6.25kg), were soaked in MeOH. It was concentrated and re-suspended in water (ca. 1000ml) to be extracted with equal volume of EtOAc to give 2.58g of EtOAc solubles. In a paper disc assay, aggregated colonies of Nostoc sp. was impregnated in 0.6% Winogradsky's agar medium, and the fraction-charged paper disc (9mm diameter, 0.25mm thick) were put onto the agar plates and incubated at 25oC. When the aggregated colonies of Nostoc sp. around the paper disc started to be dispersed within 2 days, the fraction was judged to contain HIF. The active fraction was further purified to elucidate structures of HIF. Results and Discussions) After 12-h of incubation, Nostoc sp. around 40% EtOAc fraction started to be dispersed. Under a light microscopic observation, some chain-like cells turned into hormogonia, to acquire motilitiy. Using this bioassay system, pure active principle was obtained 1mg of the colorless syrup from the 1kg fr. wt. of coralloid. In spectroscopic analyses and chemical derivatization using FD-MS, ^1H-NMR and treatment with lipase followed by released fatty acid analyses by FD-MS, it was concluded that the HIF is a 1,2-diacylglycerol possessing linolic acid and palmitic acid as constitutive fatty acids., The Janapese Society for Chemical Regulation of Plants, Japanese - Dimethyl sulfoxide添加による赤カビ病菌(Fusarium sp.)のzearalenoneとaurofusarin生合成におけるトレードオフ
小山知朗, 福士幸治, 崎浜靖子, 橋床泰之, 日本農芸化学会大会講演要旨集, 2009, 167, 05 Mar. 2009
Japanese - ホウレンソウ根腐れ病菌Aphanomyces cochlioides遊走子が持つcochliophilin Aレセプターの検出および精製
田中誠一, 崎浜靖子, 奥村知樹, 福士幸治, 田原哲士, 橋床泰之, 日本農芸化学会大会講演要旨集, 2009, 131, 05 Mar. 2009
Japanese - Study on antioxidant functions of betalain pigments isolated from red beet
Maeda Makiko, Sakihama Yasuko, Fukushi Yukiharu, Hashidoko Yasuyuki, Plant and Cell Physiology Supplement, 2009, 0, 884, 884, 2009
Betalains are plant pigments, consisting of red betacyanins and yellow betaxanthins. Distribution of betalains is limited in Caryophyllales except for Caryophyllaceae and Molluginaceae, and betalains and anthocyanins are mutually exclusive. It has been reported that flavonoids including anthocyanins have antioxidant functions in plant. However, the physiological role of betalains in plant is not clear. Here we examined betalains as antioxidant agents to elucidate their functionality.<br> Two major betalains, beet betaxanthin(BBx) and beet betacyanin(BBc), were isolated from red beet(<I>Beta vulgaris</I> L.). Both BBx and BBc were rapidly bleached by the addition of peroxynitrite(ONOO<SUP>-</SUP>). This bleaching reaction was dependent on concentration of ONOO<SUP>-</SUP>, while suppressed by glutathione, a well-known ONOO<SUP>-</SUP> scavenger. These results indicated that betalains have an ability to quench ONOO<SUP>-</SUP>. In this present study, we also discuss antioxidant activity of betalains against reactive oxygen species., The Japanese Society of Plant Physiologists - アブラナ科植物根部より分離したバクテリアによるFusarium菌糸の伸長阻害
杉田法順, 崎浜靖子, 橋床泰之, 日本農芸化学会大会講演要旨集, 2008, 83, 05 Mar. 2008
Japanese - 植物色素ベタレインの赤ビートからの単離・精製と活性窒素消去能
前田麻起子, 崎浜靖子, 福士幸治, 橋床泰之, 日本農芸化学会北海道支部・日本土壌肥料学会北海道支部・日本生物工学会北日本支部・日本応用糖質科学会北海道支部・北海道農芸化学協会合同学術講演会講演要旨, 2008, 23, 2008
Japanese - Secondary metabolites from hypoglycaemic fraction of treculia africana Decne (Moraceae)
J. Moody, O. O. Oyelola, Y. Fukushi, S. Tahara, Y. Hashidoko, Y. Sakihama, PLANTA MEDICA, 72, 11, 1078, 1078, Sep. 2006
GEORG THIEME VERLAG KG, English, Summary international conference - A photoaffinity probe designed for host-specific signal flavonoid receptors in phytopathogenic Peronosporomycete zoospores of Aphanomyces cochlioides (vol 432, pg 145, 2004)
Y Sakihama, T Shimai, M Sakasai, T Ito, Y Fukushi, Y Hashidoko, S Tahara, ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 435, 1, 241, 242, Mar. 2005, [Lead author, Corresponding author]
ELSEVIER SCIENCE INC, English - Peroxynitrite-independent nitration of plant phenolic compounds
Y Sakihama, H Shimoji, H Yamasaki, PLANT AND CELL PHYSIOLOGY, 45, S125, S125, 2004
OXFORD UNIV PRESS, English, Summary international conference - Stomatal movements induced by nitric oxide (NO)
Y Sakihama, H Yamasaki, PLANT AND CELL PHYSIOLOGY, 43, S193, S193, 2002
OXFORD UNIV PRESS, English, Summary international conference - Involvement of nitric oxide (NO) in signal transduction of stomatal opening
Sakihama Y, Yamasaki H, Proceedings of 12th International Congress on Photosynthesis, 27-009, 2002, [Peer-reviewed]
CSIRO publishing, Melbourne, English, Introduction international proceedings - Nitric oxide suppresses the energy transduction of plant mitochondria
Shimoji H, Sakihama Y, Yamasaki H, Proceedings of 12th International Congress on Photosynthesis, 29-007, 2002, [Peer-reviewed]
CSIRO publishing, Melbourne, English, Introduction international proceedings - Nitrate reductase as a producer of nitric oxide in plants
Yamasaki H, Sakihama Y, Proceedings of 12th International Congress on Photosynthesis, 21-003, 2002, [Peer-reviewed]
CSIRO publishing, Melbourne, English, Introduction international proceedings - NITRATE REDUCTASE-DEPENDENT NITRIC OXIDE PRODUNTION IN CHLAMYDOMONAS REINHARDTII :
SAKIHAMA Yasuko, NAKAMURA Soichi, YAMASAKI Hideo, Plant and cell physiology, 42, s185, 2001
Japanese Society of Plant Physiologists, English - DECLINE OF THE ASCORBATE-DEPENDENT H_2O_2 SCAVENGING SYSTEM DURING FLOWER SENESCENCE :
KAINUMA Mami, SAKIHAMA Yasuko, YAMASAKI Hideo, Plant and cell physiology, 42, s62, 2001
Japanese Society of Plant Physiologists, English - Yamasaki, H. and Sakihama, Y.:"Nitrate reductase as a producer of nitric oxide in plants" Proceedings of 12th International Congress on Photosynthesis, Brisbane, Australia [ (CD-ROM)S21-003](2001)
2001 - Cohen M.F., Sakihama, Y. and Yamasaki, H.:"Roles of plant flavonoids in interactions with microbes from protection against pathogens to the mediation of mutualism" In Recent Research Developments in Plant Physiology, Research Signpost, 2, 157-173(2001)
2001 - Sakihama, Y. and Yamasaki, H.:"Involvement of nitric oxide (NO) in signal transduction of stomatal opening", Proceedings of 12th International Congress on Photosynthesis, Brisbane, Australia[ (CD-ROM)S27-009](2001)
2001 - Shimoji, H., Sakihama, Y. and Yamasaki, H.:"Nitric oxide suppresses the energy transduction of plant mitochondria" Proceedings of 12th International Congress on Photosynthesis, Brisbane, Australia[ (CD-ROM)S29-007](2001)
2001 - モノデヒドロアスコルビン酸レダクターゼによるフェノキシルラジカルの還元
崎浜靖子, 真野純一, 佐野智, 浅田浩二, 山崎秀雄, 日本植物生理学会年会要旨集, 40th, 2000 - PHYTOPHENOXYL RADICAL AS A SUBSTRATE FOR MONODEHYDROASCORBATE REDUCTASE :
SAKIHAMA Yasuko, MANO Junichi, SANO Satoshi, ASADA Kozi, YAMASAKI Hideo, Plant and cell physiology, 41, s168, 2000
Japanese Society of Plant Physiologists, English - PRODUCTION OF ACTIVE NITROGEN SPECIES BY NITRATE REDUCTASE :
YAMASAKI Hideo, SAKIHAMA Yasuko, Plant and cell physiology, 41, s161, 2000
Japanese Society of Plant Physiologists, English - NITRIC OXIDE INHIBITS OXIDATIVE PHOSPHORYLATION IN PLANT MITOCHONDRIA :
SHIMOJI Hisashi, OHSHIRO Yuko, SAKIHAMA Yasuko, YAMASAKI Hideo, Plant and cell physiology, 41, s141, 2000
Japanese Society of Plant Physiologists, English - Polyphenols mediate lipid peroxidation in the presence of heavy metals.
SAKIHAMA Yasuko, YAMASAKI Hideo, Plant and cell physiology, 40, s103, s103, Mar. 1999
English - Flavonoid-peroxidase reaction as a mechanism for H2O2 scavenging in vascular plants.
H Yamasaki, Y Sakihama, N Ikehara, PLANT PHYSIOLOGY, 114, 3, 436, 436, Jul. 1997
AMER SOC PLANT PHYSIOLOGISTS, English, Summary international conference - LEAF-GOLDENNING CAUSED BY DYSFUNCTION OF ASCORBATE REGENERATION
YAMASAKI Hideo, HESHIKI Rika, SAKIHAMA Yasuko, IKEHARA Norikatsu, Plant and cell physiology, 37, 65, 65, Mar. 1996
English - Physiological significance of the ascorbate regenerating system for the high-light tolerance of chloroplasts
H Yamasaki, R Heshiki, T Yamasu, Y Sakihama, N Ikehara, PHOTOSYNTHESIS: FROM LIGHT TO BIOSPHERE, VOL IV, 4, 291, 294, 1995, [Peer-reviewed]
KLUWER ACADEMIC PUBL, English, Introduction international proceedings
Lectures, oral presentations, etc.
Research Themes
- Activation of human brown adipose tissue using food ingredients that enhance the bioavailability of nitric oxide
Grants-in-Aid for Scientific Research
01 Apr. 2023 - 31 Mar. 2027
若林 斉, 斉藤 昌之, 松下 真美, 米代 武司, 崎浜 靖子, 渡邊 祐介
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 23K28013 - Problem-based researches utilized by novel megalosaccharides dissolving poorly-soluble BCS II compounds
Grants-in-Aid for Scientific Research
07 Oct. 2019 - 31 Mar. 2023
木村 淳夫, 橋床 泰之, 崎浜 靖子, 奥山 正幸, 田上 貴祥
我々は世界で初めてメガロ糖（MS）の生産に成功した。性質を調べると、BCS IIに属す化合物（難水溶性・高膜透過性の薬剤や食品素材など）を可溶化する画期的な機能が発見された。またMSは「BCS II化合物を溶質とする糖質水溶化剤」と捉えることもできた。一方、難溶性ベンジル系アゾ色素もBCS IIに属し、かつ「東南アジア諸国における代表的な環境汚染物質」である点に注目し、MSとアゾ分解酵素を組合せることで、実験室レベルではあるが、色素の可溶化と酵素分解に成功した。以上は初めて生産したMS、すなわち従来型MSの知見である。極最近に従来型MSより高機能な新奇MS（新型MS）を発見した。本申請では、新型MSによるアゾ色素の酵素分解を目的とし、現地試験をタイで実施する。最終的な到達目標はアゾ色素の汚染解消（すなわち環境問題克服への貢献）である。
本年度もタイにおける新型コロナウイルス感染症の流行から渡航が困難となり、現地調査の断念を強いられた。タイでの調査が遅れているが、それを補うべき対策を立てて研究を進行させた。以下に本年度の成果を述べる。１）昨年までに我々が明らかにした有望な植物MS（日タイ共通植物由来のMS）に関し、タイ植物の存在確認を相手国研究協力者が行った。２）本MSの存在下でアゾ色素の酵素分解が進行した。３）自然界においてアゾ色素は土壌（色素汚染土壌）の中に存在するため、アゾ色素と土壌を混合させ「色素汚染土壌」のモデル化を図った。４）構築したモデル汚染土壌を滅菌後に、MS可溶化と酵素処理を実施し、アゾ色素分解の確認を行っている。分解量の向上を目指したい。
Japan Society for the Promotion of Science, Fund for the Promotion of Joint International Research (Fostering Joint International Research (B)), Hokkaido University, 19KK0147 - A cell protecting function of a plant pigment betalains against reactive oxygen and/or reactive nitrogen species
平成28年度学術研究助成・個人研究
Apr. 2017 - Mar. 2018
SAKIHAMA Yasuko
公益財団法人 飯島藤十郎記念食品科学振興財団, Principal investigator, Competitive research funding - アカビート色素ベタレインの活性窒素消去活性とその植物ストレス応答における機能
研究助成（個人研究の部）
Oct. 2015 - Mar. 2016
崎浜 靖子
公益財団法人 栗林育英学術財団, Principal investigator, Competitive research funding - Investigation for functionalities of rhizo-biocomplex to minimize highly adverse conditions in association with organic sink in the rhizosphere and its utilization in agricultural use
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2008 - 2011
HASHIDOKO Yasuyuki, HARAGUCHI Akira, KIMURA Atsuo, SAKIHAMA Yasuko, TAMAI Yutaka, MATSUURA Hideyuki
We investigated rhizo-biosystems that enable to mitigate adverse soils in Kalimantan, Indonesia. Burkholderia sp. strain A-KA that had been isolated from the rhizosphere of Imperata cylindrica grown in medium-strongly acidic peatland showed a growth-helper activity toward other rhizosphere bacteria, such as Sphingomonas sp. Burkholderia mimosarum isolated from rhizosphere of paddy rice tolerant to acid-sulfate soil suppressed tropolone production of B. plantarii, a bacterium causative of rice blight disease, while promoted growth of diverse root-and seed-epiphytic bacteria. Among rhizobacteria that had isolated from dipterocarpous sapling adapting to polyphenol-rich tropical peat soil, pyrogallol-containing plant polyphenols activated Burkholderia unamae CK-43B to degrade indole and some other N-heterocyclic aromatic compounds. In the coralloid root symbiotic systems between Cycas revoluta root and a nitrogen-fixing cyanobacterium Nostoc punchiforme, a diacylglycerol was found to be the principle of hormogoniu-inducing factor on the cyanobacterium necessary to its host-recognition. Also, we successfully isolated and characterized signal compounds from a rhizobacterium Pseudomonas jessenii strain EC-S101 isolated from spinach root and from a rhizosphere fungus Trichoderma virens strain PS1-7 isolated from paddy root. In the rhizosphere, nitrous oxide emitting bacteria in tropical peat soil were missing their nitrous oxide reductase (N2OR) genes, and affected its denitrification by several secondary metabolites of plants
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 20248033 - 植物病原性卵菌類の二次代謝産物を介した宿主認識及び感染分子機構に関する研究
科学研究費補助金（若手研究B)
Apr. 2006 - Mar. 2008
崎浜 靖子
ダイズ茎疫病菌Phytophthora sojae及びホウレンソウ根腐れ病菌Aphanomyces cochlioidesの遊走子細胞は、宿主植物から滲出する二次代謝産物フラボノイドを認識し、被嚢化、発芽という感染時形態変化を起こす。被嚢化は物理的刺激によっても起こるが、宿主認識物質が存在しない場合には発芽せずに遊走子を再生するため感染には至らない。しかし、動植物の細胞内シグナル物質として知られている一酸化窒素(NO)によって宿主認識物質なしでも遊走子の被嚢化・発芽が促進されることが観察された。また、P. soae遊走子をNOの消去剤であるcarboxy-PTIOで処理すると発芽した菌糸の伸長が有意に阻害された。これらの結果は、菌糸の伸長にNOが関与していることを示している。また、被嚢化後、発芽または再生遊走子のどちらに分化するのかそのギアチェンジに関わる遺伝子を探索するため、発芽を誘引する宿主認識物質処理(A)と遊走子再生を誘引する物理的刺激(B)によって被濃化させた胞子に特異的に発現している遺伝子を調べた。その結果、(A)では細胞骨格維持に関わる膜タンパク質、(B)ではアクチン構築に関与するタンパク質をコードする遺伝子が発現していた。
本研究課題の遂行により、卵菌においてNO依存性シグナル伝達系が宿主感染機構に重要な役割を果たしている可能性が示唆され、宿主感染成立のキーステップである被嚢化から発芽への細胞分化に関わる遺伝子が見いだされた。これらの結果は感染システムのさらなる解明と新たな防除法の確立に応用できる重要な知見であると期待される。
日本学術振興会, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 18780026 - 植物病原性卵菌類の感染時シグナル伝達機構について
科学研究費補助金（若手研究B)
Apr. 2004 - Mar. 2006
崎浜 靖子
Principal investigator, Competitive research funding - 植物病原性卵菌の感染時シグナル伝達系における一酸化窒素(NO)の影響に関する研究
科学研究費助成事業
2004 - 2005
崎浜 靖子
植物病原性卵菌類であるAphanomyces及びPhytophthoraは、遊泳能力を持つ遊走子細胞を形成することにより宿主植物に到達し感染する。その際、遊走子は被嚢化しさらに被嚢胞子の発芽が起こる。この遊走子形態変化は宿主感染機構において重要な過程であるがその分子機構については不明な点が多い。本研究では、遊走子の形態変化分子機構解明とその制御に関わる基礎的知見を得ることを目的とし、動植物で様々な生理作用を示す一酸化窒素(NO)の遊走子被嚢化及び発芽に対する影響を調べた。
Aphanomyces cochlioides及びPhytophthora sojae遊走子を自発的NO発生試薬であるNOC5またはNOR3で処理したところ、被嚢化及び発芽率が有意に上昇した。また、哺乳類型NO合成酵素(NOS)の基質であるアルギニンでも遊走子の発芽促進が観察されたため、DOE Joint Genome InstituteのP.sojaeゲノムデータベースを用いNOS様遺伝子の探索を行ったところ、アミノ酸配列で70%の相同性を持つ遺伝子が存在した。しかし、この遺伝子はオキシダーゼドメインを欠いており、同遺伝子を導入した大腸菌ではアルギニン由来のNO生成活性は確認出来なかった。また、脱窒菌や一部の真菌では脱窒過程においてNOを生成することが報告されていることから、脱窒に関わる酵素群遺伝子についても検索したところ、亜硝酸をNOに変換する亜硝酸還元酵素と高い相同性をもつ遺伝子が見つかった。
本研究課題の遂行により、A.cochlioides及びP.sojae遊走子の被嚢化及び発芽機構にNOが大きな影響を与える事が分かった。卵菌類の遊走子は宿主植物に到達できなかった場合は被嚢化しても発芽せずに再度遊走子を作りだすが、NOによって遊走子を強制的に被嚢化・発芽させる"自殺発芽誘導法"等の新たな駆除法の開発への応用が期待される。
日本学術振興会, 若手研究(B), 北海道大学, 16780028 - Studies on the Molecular Mechanism in Life-cycle Development and Signal Trnnsduction of Aphanomyces cochlioides, a Cause of Spinach Root Rot
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A)
2002 - 2004
TAHARA Satoshi, YOSHIHARA Teruhiko, HASHIDOKO Yasuyuki, FUKUSHI Yukiharu, SAKIHAMA Yasuko
1.The zoospores of phytopathogenic Oomycete, Aphanomyces cochlioides show clear positive chemotaxis to the host-specific singanl substances. The reputed receptor for the host-specific attractant toward the zoospores of spinach root rot pathogen, A.cochlioides wsa surveyed by using a biotin conjugated azidoflavone as a probe and resulted in 40 and 70 kDa membrane proteins on electropholetic gel plates.
2.The events caused by signal transduction regarding the life-cycle development of a Peronosporomycete (Oomycete) Aphanonyres cochlioides has been studied by using microscopic techniques. An interesting difference in F-actin profiles was observe between two kinds of custospores, one developing ahead to hyphal germination and the other rejuvenating to regeneration of zoospores.
3.About 150 rhizoplane bacteria were isolated from host and non-host plants, and our dual culture bioassay revealed that more than 5 % of isolates caused severe morphological alterations on phytopathogenic Oomycete Aphanomyces cochlioides and the fungal growth was strongly inhibited. From these results, we proposed that this method is new and effective way to find biological control agents against soilbome phytopathogens.
4.Cochliophilin A (5-hydroxy-6,7-methylenedioxyflavone) known as the host-specific zoospore attractant for a spinach root rot pathogen has been isolated so far only from Chenopodiaceae plants, spinach, sugar beet, and Chenopodium album, however, in our recent survey of zoospore attractants in Amamthaceae plant, Celosia cristata revealed that one of the active princilpes was indeed cochliophilin A.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), HOKKAIDO UNIVERSITY, 14206013 - 高等植物におけるフラボノイドの抗酸化機能
Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows
2000 - 2001
崎浜 靖子
Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, University of the Ryukyus, 00J00072 - 熱帯植物の可塑性における転移因子の役割
Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas (C)
2000 - 2000
山崎 秀雄, 崎浜 靖子
生物の種多様性は熱帯・亜熱帯域の低緯度地域で高く、高緯度地域になるに従って減少することが知られている。しかし、依然として種の多様性を生み出すメカニズムは不明である。本研究計画では、沖縄に自生しているクロトンを用いて、多様性創出における転移因子の役割について基礎的知見を得ることを目的とした。6系統のクロトンについて、ヨナグニサン(蛾)Mariner-Like Element(MLE)配列中の転移酵素に対するコンセンサスプライマー用いPCR増幅を行った。その結果、用いた全ての系統において予測される500bpのバンドが検出され、MLEの存在が示唆された。RNA型転移因子の一つであるTy1/Copiaの逆転写酵素の配列に対するdegenerate PCRをおこなった結果、約300bpのPCRクローンが得られ、ワタのTy1/Copiaレトロポゾンと68%の相同性を示した。マングローブを含む樹木性熱帯植物27種の中で、デイゴとフクギからクロトンと同様なMLEのPCRクローンが得られた。今回、同所的に生息する昆虫のMLEが植物であるクロトンに見いだされたことと、クロトン以外の熱帯植物にも同様な配列が認められたことは、MLEが種を越えて同所的に水平伝播していることを強く示唆している。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research on Priority Areas (C), University of the Ryukyus, 12202043
