研究者詳細 - 中村　宜督

論文 - 中村　宜督

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A novel tag-free probe for targeting molecules interacting with a flavonoid catabolite 査読

Sayaka Nakashima, Zhe Liu, Yuya Yamaguchi, Shunya Saiki, Shintaro Munemasa, Toshiyuki Nakamura, Yoshiyuki Murata, Yoshimasa Nakamura

Biochemistry and Biophysics Reports 7 240 - 245 2016年9月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Elsevier B.V.

3,4-Dihydroxyphenylacetic acid (DOPAC) is one of the colonic microflora-produced catabolites of quercetin 4'-glucoside (Q4'G). Although the interaction of DOPAC with cellular proteins might be involved in its biological activity, the actual proteins have not yet been identified. In this study, we developed a novel tag-free DOPAC probe to label the targeted proteins by the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) and verified its efficacy. Various labeled proteins were detected by the DOPAC probe with the azide labeled biotin and a horseradish peroxidase (HRP)-streptavidin complex. Furthermore, a pulldown assay identified Keap1 and aryl hydrocarbon receptor (AhR) as the target proteins for the phase 2 enzyme up-regulation.

DOI： 10.1016/j.bbrep.2016.06.020

Involvement of OST1 Protein Kinase and PYR/PYL/RCAR Receptors in Methyl Jasmonate-Induced Stomatal Closure in Arabidopsis Guard Cells 査読

Ye Yin, Yuji Adachi, Yoshimasa Nakamura, Shintaro Munemasa, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 57 ( 8 ) 1779 - 1790 2016年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

Methyl jasmonate (MeJA) induces stomatal closure. It has been shown that stomata of many ABA-insensitive mutants are also insensitive to MeJA, and a low amount of ABA is a prerequisite for the MeJA response. However, the molecular mechanisms of the interaction between ABA and MeJA signaling remain to be elucidated. Here we studied the interplay of signaling of the two hormones in guard cells using the quadruple ABA receptor mutant pyr1 pyl1 pyl2 pyl4 and ABA-activated protein kinase mutants ost1-2 and srk2e. In the quadruple mutant, MeJA-induced stomatal closure, H2O2 production, nitric oxide (NO) production, cytosolic alkalization and plasma membrane Ca2+-permeable current (I-Ca) activation were not impaired. At the same time, the inactivation of the inward-rectifying K+ current was impaired. In contrast to the quadruple mutant, MeJA-induced stomatal closure, H2O2 production, NO production and cytosolic alkalization were impaired in ost1-2 and srk2e as well as in aba2-2, the ABA-deficient mutant. The activation of ICa was also impaired in srk2e. Collectively, these results indicated that OST1 was essential for MeJA-induced stomatal closure, while PYR1, PYL1, PYL2 and PYL4 ABA receptors were not sufficient factors. MeJA did not appear to activate OST1 kinase activity. This implies that OST1 mediates MeJA signaling through an undetectable level of activity or a nonenzymatic action. MeJA induced the expression of an ABA synthesis gene, NCED3, and increased ABA contents only modestly. Taken together with previous reports, this study suggests that MeJA signaling in guard cells is primed by ABA and is not brought about through the pathway mediated by PYR1, PYL1 PYL2 and PYL4.

DOI： 10.1093/pcp/pcw102

Apoptosis induction is involved in UVA-induced autolysis in sea cucumber Stichopus japonicus 査読

Hang Qi, Hui Fu, Xiufang Dong, Dingding Feng, Nan Li, Chengrong Wen, Yoshimasa Nakamura, Beiwei Zhu

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 158 130 - 135 2016年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCIENCE SA

Autolysis easily happens to sea cucumber (Stichopus japonicus, S. japonicus) for external stimulus like UV exposure causing heavy economic losses. Therefore, it is meaningful to reveal the mechanism of S. japonicas autolysis. In the present study, to examine the involvement of apoptosis induction in UVA-induced autolysis of S. japonicas, we investigated the biochemical events including the DNA fragmentation, caspase-3 activation, mitogen-activated protein kinases (MAPKs) phosphorylation and free radical formation. Substantial morphological changes such as intestine vomiting and dermatolysis were observed in S. japonicus during the incubation after 1-h UVA irradiation (10 W/m(2)). The degradation of the structural proteins and enhancement of cathepsin L activity were also detected, suggesting the profound impact of proteolysis caused by the UVA irradiation even for 1 h. Furthermore, the DNA fragmentation and specific activity of caspase-3 was increased up to 12 h after UVA irradiation. The levels of phosphorylated p38 mitogen activated protein kinase (MAPK) and phosphorylated c-jun.-N-terminal kinase (JNK) were significantly increased by the UVA irradiation for 1 h. An electron spin resonance (ESR) analysis revealed that UVA enhanced the free radical formation in S. japonicas, even through we could not identify the attributed species. These results suggest that UVA-induced autolysis in S. japonicas at least partially involves the oxidative stress-sensitive apoptosis induction pathway. These data present a novel insight into the mechanisms of sea cucumber autolysis induced by external stress. (C) 2016 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotobiol.2016.02.034

A mushroom-derived amino acid, ergothioneine, is a potential inhibitor of inflammation-related DNA halogenation 査読

Takashi Asahi, Xiaohong Wu, Hiroshi Shimoda, Shinsuke Hisaka, Etsuko Harada, Tomomi Kanno, Yoshimasa Nakamura, Yoji Kato, Toshihiko Osawa

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 80 ( 2 ) 313 - 317 2016年2月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

Myeloperoxidase (MPO)-generated halogenating molecules, such as hypochlorous acid and hypobromous acid (HOBr), in inflammatory regions are postulated to contribute to disease progression. In this study, we showed that ergothioneine (EGT), derived from an edible mushroom, inhibited MPO activity as well as the formation of 8-bromo-2-deoxyguanosine in vitro. The HOBr scavenging effect of EGT is higher than those of ascorbic acid and glutathione. We initially observed that the administration of Coprinus comatus, an edible mushroom containing a high amount of EGT, inhibited the UV-B-induced inflammatory responses and DNA halogenation, suggesting that EGT is a promising anti-inflammatory agent from mushrooms.

DOI： 10.1080/09168451.2015.1083396

アブラナ科野菜漬物（カブ，ハクサイ）のイソチオシアネート生成に関する塩化ナトリウム（NaCl）およびアスコルビン酸の影響査読

宮澤紀子, 阿部雅子, 木村典代, 松岡寛樹, 田中進, 森光康次郎, 中村宜督, 綾部園子, 小澤好夫

日本調理科学会誌 49 ( 2 ) 138 - 146 2016年

記述言語：日本語出版者・発行元：一般社団法人日本調理科学会

野菜を常に摂取すると生活習慣病のリスクを軽減することが知られている。日本では，グルコシノレートを含む多くのアブラナ科野菜が漬物や煮物さらに浅漬けとして消費されている。グルコシノレートは組織が損傷するとミロシナーゼにより独特なフレーバーと発がん抑制作用を有するイソチオシアネートに加水分解される。 NaClとアスコルビン酸（VC）がミロシナーゼ活性に与える影響について検討した結果，1％NaClと0.1％VC濃度が最もミロシナーゼ活性を賦活した。一方，NaClとVCの共存においては，活性は抑制されたが，その抑制率はVC濃度が増加するに従い減少した。さらに，漬物中のイソチオシアネート生成へのNaClの影響を検討するために，1, 2および3％NaCl濃度のカブとハクサイの浅漬けを調製した。GC-MS分析により3－ブテニル，4－ペンテニル，フェネチルイソチオシアネートを検出した。これらは，カブ，ハクサイ共に3％NaCl濃度で最も多く生成し，0.4％VCの添加は，1.4～1.6倍イソチオシアネートの生成を増大させた。官能評価により2％NaCl濃度における浅漬けが好まれた。

DOI： 10.11402/cookeryscience.49.138

Plant Polyphenols as a Double-Edged Sword in Health Promotion : Lessons from the Experimental Models Using Simple Phenolic Acids 招待査読

Nakamura Yoshimasa

Agri-bioscience monographs AGBM 6 ( 1 ) 1 - 57 2016年

Specific role of taurine in the 8-brominated-2′-deoxyguanosine formation 査読

Takashi Asahi, Takashi Asahi, Yoshimasa Nakamura, Yoji Kato, Toshihiko Osawa

Archives of Biochemistry and Biophysics 586 45 - 50 2015年11月

担当区分：責任著者記述言語：英語掲載種別：研究論文（学術雑誌）

© 2015 Elsevier Inc. All rights reserved. At the sites of inflammation, hypohalous acids, such as hypochlorous acid and hypobromous acid (HOBr), are produced by myeloperoxidase. These hypohalous acids rapidly react with the primary amino groups to produce haloamines, which are relatively stable and can diffuse long distances and cross the plasma membrane. In this study, we examined the effects of taurine, the most abundant free amino acid in the leukocyte cytosol, on the hypohalous acid-dependent formation of 8-chloro-2′-deoxyguanosine (8-CldG) and 8-bromo-2′-deoxyguanosine (8-BrdG). The reaction of taurine with HOBr yielded taurine bromamine, which is the most stable among other bromamines of amino acids. Taurine also enhanced the bromination of only dG among the four 2′-deoxynucleosides, whereas it inhibited the 8-CldG formation. The specificity of taurine for the enhanced formation of halogenated dG is completely different from that of nicotine, an enhancer of chlorination. The amount of dibrominated taurine (taurine dibromamine) closely correlated with the formation of 8-BrdG, suggesting that taurine dibromamine might be a plausible mediator for the dG bromination in vivo.

DOI： 10.1016/j.abb.2015.10.002

Allyl isothiocyanate induces stomatal closure in Vicia faba 査読

Muhammad Abdus Sobahan, Nasima Akter, Eiji Okuma, Misugi Uraji, Wenxiu Ye, Izumi C. Mori, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 10 ) 1737 - 1742 2015年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

Isothiocyanates are enzymatically produced from glucosinolates in plants, and allyl isothiocyanate (AITC) induces stomatal closure in Arabidopsis thaliana. In this study, we investigated stomatal responses to AITC in Vicia faba. AITC-induced stomatal closure accompanied by reactive oxygen species (ROS) and NO production, cytosolic alkalization and glutathione (GSH) depletion in V. faba. GSH monoethyl ester induced stomatal reopening and suppressed AITC-induced GSH depletion in guard cells. Exogenous catalase and a peroxidase inhibitor, salicylhydroxamic acid, inhibited AITC-induced stomatal closure, unlike an NAD(P)H oxidase inhibitor, diphenylene iodonium chloride. The peroxidase inhibitor also abolished the AITC-induced ROS production, NO production, and cytosolic alkalization. AITC-induced stomatal closure was suppressed by an NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and an agent to acidify cytosol, butyrate. These results indicate that AITC-induced stomatal closure in V. faba as well as in A. thaliana and suggest that AITC signaling in guard cells is conserved in both plants.

DOI： 10.1080/09168451.2015.1045827

Two guard cell mitogen-activated protein kinases, MPK9 and MPK12, function in methyl jasmonate-induced stomatal closure in Arabidopsis thaliana 査読

Md. A. R. Khokon, M. A. Salam, F. Jammes, W. Ye, M. A. Hossain, M. Uraji, Y. Nakamura, I. C. Mori, J. M. Kwak, Y. Murata

PLANT BIOLOGY 17 ( 5 ) 946 - 952 2015年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Methyl jasmonate (MeJA) and abscisic acid (ABA) signalling cascades share several signalling components in guard cells. We previously showed that two guard cell-preferential mitogen-activated protein kinases (MAPKs), MPK9 and MPK12, positively regulate ABA signalling in Arabidopsis thaliana. In this study, we examined whether these two MAP kinases function in MeJA signalling using genetic mutants for MPK9 and MPK12 combined with a pharmacological approach. MeJA induced stomatal closure in mpk9-1 and mpk12-1 single mutants as well as wild-type plants, but not in mpk9-1 mpk12-1 double mutants. Consistently, the MAPKK inhibitor PD98059 inhibited the MeJA-induced stomatal closure in wild-type plants. MeJA elicited reactive oxygen species (ROS) production and cytosolic alkalisation in guard cells of the mpk9-1, mpk12-1 and mpk9-1 mpk12-1 mutants, as well in wild-type plants. Furthermore, MeJA triggered elevation of cytosolic Ca2+ concentration ([Ca2+](cyt)) in the mpk9-1 mpk12-1 double mutant as well as wild-type plants. Activation of S-type anion channels by MeJA was impaired in mpk9-1 mpk12-1. Together, these results indicate that MPK9 and MPK12 function upstream of S-type anion channel activation and downstream of ROS production, cytosolic alkalisation and [Ca2+](cyt) elevation in guard cell MeJA signalling, suggesting that MPK9 and MPK12 are key regulators mediating both ABA and MeJA signalling in guard cells.

DOI： 10.1111/plb.12321

Open Stomata 1 Kinase is Essential for Yeast Elicitor-Induced Stomatal Closure in Arabidopsis 査読

Wenxiu Ye, Yuji Adachi, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

PLANT AND CELL PHYSIOLOGY 56 ( 6 ) 1239 - 1248 2015年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：OXFORD UNIV PRESS

We recently demonstrated that yeast elicitor (YEL)-induced stomatal closure requires a Ca2+-dependent kinase, CPK6. A Ca2+-independent kinase, Open Stomata 1 (OST1), is involved in stomatal closure induced by various stimuli including ABA. In the present study, we investigated the role of OST1 in YEL-induced stomatal closure in Arabidopsis using a knock-out mutant, ost1-3, and a kinase-deficient mutant, ost1-2. YEL did not induce stomatal closure or activation of guard cell S-type anion channels in the ost1 mutants unlike in wild-type plants. However, YEL did not increase OST1 kinase activity in wild-type guard cells. The YEL-induced stomatal closure and activation of S-type anion channels were also impaired in a gain-of-function mutant of a clade A type 2C protein phosphatase (ABA INSENSITIVE 1), abi1-1C. In the ost1 mutants like in the wild type, YEL induced H2O2 accumulation, activation of non-selective Ca2+-permeable cation (I-Ca) channels and transient elevations in cytosolic free Ca2+ concentration ([Ca2+](cyt)) in guard cells. These results suggest that OST1 kinase is essential for stomatal closure and activation of S-type anion channels induced by YEL and that OST1 is not involved in H2O2 accumulation, I-Ca channel activation or [Ca2+](cyt) elevations in guard cells induced by YEL.

DOI： 10.1093/pcp/pcv051

Benzyl isothiocyanate inhibits IL-13 expression in human basophilic KU812 cells 査読

Yue Tang, Naomi Abe, Motoko Yoshimoto, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 1 ) 159 - 163 2015年1月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

An allergen-stimulating cytokine, interleukin-13 (IL-13), plays a significant role in allergic inflammation. Benzyl isothiocyanate (BITC), derived from several cruciferous vegetables, significantly suppressed the IL-13 expression in the calcium ionophore-stimulated human basophilic KU812 cells. Down-regulation of phosphorylated mitogen-activated protein kinases as well as nuclear transcriptional factors might be involved in the underlying mechanism.

DOI： 10.1080/09168451.2014.963503

Inhibition by acrolein of light-induced stomatal opening through inhibition of inward-rectifying potassium channels in Arabidopsis thaliana 査読

Md. Moshiul Islam, Wenxiu Ye, Daiki Matsushima, Md. Atiqur Rahman Khokon, Shintaro Munemasa, Yoshimasa Nakamura, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 79 ( 1 ) 59 - 62 2015年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

Acrolein is a reactive alpha,beta-unsaturated aldehyde derived from lipid peroxides, which are produced in plants under a variety of stress. We investigated effects of acrolein on light-induced stomatal opening using Arabidopsis thaliana. Acrolein inhibited light-induced stomatal opening in a dose-dependent manner. Acrolein at 100 mu M inhibited plasma membrane inward-rectifying potassium (K-in) channels in guard cells. Acrolein at 100 mu M inhibited K-in channel KAT1 expressed in a heterologous system using Xenopus leaves oocytes. These results suggest that acrolein inhibits light-induced stomatal opening through inhibition of K-in channels in guard cells.

DOI： 10.1080/09168451.2014.951028

Cyclic adenosine 5 '-diphosphoribose (cADPR) cyclic guanosine 3 ',5 '-monophosphate positively function in Ca2+ elevation in methyl jasmonate-induced stomatal closure, cADPR is required for methyl jasmonate-induced ROS accumulation NO production in guard cells 査読

M. A. Hossain, W. Ye, S. Munemasa, Y. Nakamura, I. C. Mori, Y. Murata

PLANT BIOLOGY 16 ( 6 ) 1140 - 1144 2014年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Methyl jasmonate (MeJA) signalling shares several signal components with abscisic acid (ABA) signalling in guard cells. Cyclic adenosine 5-diphosphoribose (cADPR) and cyclic guanosine 3,5-monophosphate (cGMP) are second messengers in ABA-induced stomatal closure. In order to clarify involvement of cADPR and cGMP in MeJA-induced stomatal closure in Arabidopsis thaliana (Col-0), we investigated effects of an inhibitor of cADPR synthesis, nicotinamide (NA), and an inhibitor of cGMP synthesis, LY83583 (LY, 6-anilino-5,8-quinolinedione), on MeJA-induced stomatal closure. Treatment with NA and LY inhibited MeJA-induced stomatal closure. NA inhibited MeJA-induced reactive oxygen species (ROS) accumulation and nitric oxide (NO) production in guard cells. NA and LY suppressed transient elevations elicited by MeJA in cytosolic free Ca2+ concentration ([Ca2+](cyt)) in guard cells. These results suggest that cADPR and cGMP positively function in [Ca2+](cyt) elevation in MeJA-induced stomatal closure, are signalling components shared with ABA-induced stomatal closure in Arabidopsis, and that cADPR is required for MeJA-induced ROS accumulation and NO production in Arabidopsis guard cells.

DOI： 10.1111/plb.12175

Tea Catechins Inhibit Cell Proliferation Through Hydrogen Peroxide-Dependent and -Independent Pathways in Human T lymphocytic Leukemia Jurkat Cells 査読

Yue Tang, Naomi Abe, Hang Qi, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

FOOD SCIENCE AND TECHNOLOGY RESEARCH 20 ( 6 ) 1245 - 1249 2014年11月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：KARGER

In the present study, we investigated the anti-proliferative effects of four tea catechins: (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg) and (-)-epigallocatechin gallate (EGCg) in human T lymphocytic leukemia Jurkat cells. Each catechin induced a significant cytotoxic effect on Jurkat cells. Combinations of EGCg with other catechins additively potentiated anti-proliferation, extracellular hydrogen peroxide formation, c-Jun N-terminal kinase (JNK) activation and interferon (IFN)-gamma mRNA expression. Catalase partly but significantly abolished the cytotoxicity induced by EGC or EGCg, whereas it did not influence the EC- or ECg-induced effect. Among the tea catechins, ECg synergistically enhanced the EGCg-induced JNK phosphorylation and IFN-gamma expression. The present findings provide evidence that tea catechins are able to concertedly induce cytotoxicity through the JNK/IFN-gamma pathway in both a hydrogen peroxide-dependent and -independent manner.

DOI： 10.3136/fstr.20.1245

(-)-Epigallocatechin-3-Gallate Ameliorates Photodynamic Therapy Responses in an In Vitro T Lymphocyte Model 査読

Hang Qi, Naomi Abe, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

PHYTOTHERAPY RESEARCH 28 ( 10 ) 1486 - 1491 2014年10月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

(-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic constituent in green tea, is known as a powerful antioxidant but concomitantly possesses a prooxidant property. We investigated the effect of EGCG on phloxine B (PhB)-induced photocytotoxicity in human T lymphocytic leukemia Jurkat cells. EGCG significantly potentiated PhB-induced photocytotoxic effects, including the inhibition of cell proliferation, DNA fragmentation, and caspase-3 activity induction in Jurkat cells. Catalase attenuated the enhanced cytotoxicity by EGCG, suggesting the involvement of extracellularly produced hydrogen peroxide. Indeed, EGCG significantly enhanced extracellular hydrogen peroxide formation induced by photo-irradiated PhB. The EGCG also enhanced intracellular reactive oxygen species accumulation, c-Jun N-terminal kinase (JNK) phosphorylation, and interferon- (IFN-) gene expression, all of which are involved in PhB-induced apoptosis. Taken together, our data suggest that EGCG is capable of potentiating photodynamic therapy responses, presumably through the intracellular oxidative stress-sensitive JNK/IFN- pathway by exogenous hydrogen peroxide formation. Copyright (c) 2014 John Wiley & Sons, Ltd.

DOI： 10.1002/ptr.5152

Thiol modification by bioactivated polyphenols and its potential role in skin inflammation 査読

Yoshimasa Nakamura, Takeshi Ishii, Naomi Abe, Yoshiyuki Murata

BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 78 ( 6 ) 1067 - 1070 2014年6月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：TAYLOR & FRANCIS LTD

In the present study, we evaluated the modifying behavior of simple phenolic compounds on the sulfhydryl groups of glutathione and proteins. The catechol-type polyphenols, including protocatechuic acid, but neither the monophenols nor O-methylated catechol, can modify the sulfhydryl groups in a phenol oxidase-dependent manner. The possible involvement of polyphenol bioactivation in the enhancement of skin inflammation was also suggested.

DOI： 10.1080/09168451.2014.905190

Ascorbic Acid Synergistically Potentiates Phloxine B-induced Photocytotoxicity in Human Acute Promyelocytic Leukemia Cells 査読

Hang Qi, Qian Wu, Naomi Abe, Shunya Saiki, Beiwei Zhu, Yoshiyuki Murata, Yoshimasa Nakamura

JOURNAL OF BIOCHEMICAL AND MOLECULAR TOXICOLOGY 28 ( 4 ) 167 - 173 2014年4月

担当区分：最終著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-BLACKWELL

Ascorbic acid (AsA) is known as an antioxidant but concomitantly possesses a pro-oxidant property. Because the impact of AsA on photodynamic therapy response is unclear, we investigated the effect of AsA on photocytotoxicity induced by phloxine B in human acute promyelocytic leukemia HL-60 cells. AsA synergistically enhanced phloxine B-induced photocytotoxic effects, including inhibition of cell proliferation, DNA ladder formation, and caspase-3 activation, whereas AsA itself showed no photocytotoxicity. AsA also enhanced the consumption of the reduced glutathione level compared with the cells treated with phloxine B alone under the light condition. Combination of AsA with phloxine B under the light condition enhanced the phosphorylation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase (MAPK). These effects were completely cancelled by catalase. These results suggest that AsA synergistically enhances phloxine B-induced photocytotoxicity, possibly through the extracellular oxidative stress-dependent MAPK pathway activation.

DOI： 10.1002/jbt.21549

Regulation of reactive oxygen species-mediated abscisic acid signaling in guard cells and drought tolerance by glutathione 査読

Shintaro Munemasa, Daichi Muroyama, Hiroki Nagahashi, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Frontiers in Plant Science 4 2013年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Frontiers Research Foundation

The phytohormone abscisic acid (ABA) induces stomatal closure in response to drought stress, leading to reduction of transpirational water loss. A thiol tripeptide glutathione (GSH) is an important regulator of cellular redox homeostasis in plants. Although it has been shown that cellular redox state of guard cells controls ABA-mediated stomatal closure, roles of GSH in guard cell ABA signaling were largely unknown. Recently we demonstrated that GSH functions as a negative regulator of ABA signaling in guard cells. In this study we performed more detailed analyses to reveal how GSH regulates guard cell ABA signaling using the GSH-deficient Arabidopsis mutant cad2-1. The cad2-1 mutant exhibited reduced water loss from rosette leaves. Whole-cell current recording using patch clamp technique revealed that the cad2-1 mutation did not affect ABA regulation of S-type anion channels. We found enhanced activation of Ca2+ permeable channels by hydrogen peroxide (H2O2) in cad2-1 guard cells. The cad2-1 mutant showed enhanced H2O2-induced stomatal closure and significant increase of ROS accumulation in whole leaves in response to ABA. Our findings provide a new understanding of guard cell ABA signaling and a new strategy to improve plant drought tolerance. © 2013 Munemasa, Muroyama, Nagahashi, Nakamura, Mori and Murata.

DOI： 10.3389/fpls.2013.00472

Erratum: Role of protein tyrosine phosphatase 1B in vascular endothelial growth factor signaling and cell-cell adhesions in endothelial cells (Circulation Research (2008) 102 (1182-1191) DOI: 10.1161/ CIRCRESAHA.107. 167080) 査読

Y. Nakamura, N. Patrushev, H. Inomata, D. Mehta, N. Urao, H. W. Kim, M. Razvi, V. Kini, K. Mahadev, B. J. Goldstein, R. McKinney, T. Fukai, M. Ushi-Fukai

Circulation Research 113 2013年10月

Calcium-dependent protein Kinase CPK6 positively functions in induction by yeast elicitor of stomatal closure and inhibition by yeast elicitor of light-induced stomatal opening in Arabidopsis 査読

Wenxiu Ye, Daichi Muroyama, Shintaro Munemasa, Yoshimasa Nakamura, Izumi C. Mori, Yoshiyuki Murata

Plant Physiology 163 ( 2 ) 591 - 599 2013年10月

記述言語：英語掲載種別：研究論文（学術雑誌）

Yeast elicitor (YEL) induces stomatal closure that is mediated by a Ca2+-dependent signaling pathway. A Ca2+-dependent protein kinase, CPK6, positively regulates activation of ion channels in abscisic acid and methyl jasmonate signaling, leading to stomatal closure in Arabidopsis (Arabidopsis thaliana). YEL also inhibits light-induced stomatal opening. However, it remains unknown whether CPK6 is involved in induction by YEL of stomatal closure or in inhibition by YEL of light-induced stomatal opening. In this study, we investigated the roles of CPK6 in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis. Disruption of CPK6 gene impaired induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening. Activation by YEL of nonselective Ca2+-permeable cation channels was impaired in cpk6-2 guard cells, and transient elevations elicited by YEL in cytosolic-free Ca2+ concentration were suppressed in cpk6-2 and cpk6-1 guard cells. YEL activated slow anion channels in wild-type guard cells but not in cpk6-2 or cpk6-1 and inhibited inward-rectifying K+ channels in wild-type guard cells but not in cpk6-2 or cpk6-1. The cpk6-2 and cpk6-1 mutations inhibited YEL-induced hydrogen peroxide accumulation in guard cells and apoplast of rosette leaves but did not affect YEL-induced hydrogen peroxide production in the apoplast of rosette leaves. These results suggest that CPK6 positively functions in induction by YEL of stomatal closure and inhibition by YEL of light-induced stomatal opening in Arabidopsis and is a convergent point of signaling pathways for stomatal closure in response to abiotic and biotic stress. © 2013 American Society of Plant Biologists. All Rights Reserved.

DOI： 10.1104/pp.113.224055

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