Research activity information

• Photo-oxidative damage of photosystem I by repetitive flashes and chilling stress in cucumber leaves

  Ginga Shimakawa, Pavel Müller, Chikahiro Miyake, Anja Krieger-Liszkay, Pierre Sétif

  Nov. 2024, Biochimica et Biophysica Acta (BBA) - Bioenergetics

  Scientific journal


• Enhanced Reduction of Ferredoxin in PGR5-Deficient Mutant of Arabidopsis thaliana Stimulated Ferredoxin-Dependent Cyclic Electron Flow around Photosystem I.

  Shu Maekawa, Miho Ohnishi, Shinya Wada, Kentaro Ifuku, Chikahiro Miyake

  The molecular entity responsible for catalyzing ferredoxin (Fd)-dependent cyclic electron flow around photosystem I (Fd-CEF) remains unidentified. To reveal the in vivo molecular mechanism of Fd-CEF, evaluating ferredoxin reduction-oxidation kinetics proves to be a reliable indicator of Fd-CEF activity. Recent research has demonstrated that the expression of Fd-CEF activity is contingent upon the oxidation of plastoquinone. Moreover, chloroplast NAD(P)H dehydrogenase does not catalyze Fd-CEF in Arabidopsis thaliana. In this study, we analyzed the impact of reduced Fd on Fd-CEF activity by comparing wild-type and pgr5-deficient mutants (pgr5hope1). PGR5 has been proposed as the mediator of Fd-CEF, and pgr5hope1 exhibited a comparable CO2 assimilation rate and the same reduction-oxidation level of PQ as the wild type. However, P700 oxidation was suppressed with highly reduced Fd in pgr5hope1, unlike in the wild type. As anticipated, the Fd-CEF activity was enhanced in pgr5hope1 compared to the wild type, and its activity further increased with the oxidation of PQ due to the elevated CO2 assimilation rate. This in vivo research clearly demonstrates that the expression of Fd-CEF activity requires not only reduced Fd but also oxidized PQ. Importantly, PGR5 was found to not catalyze Fd-CEF, challenging previous assumptions about its role in this process.

  Feb. 2024, International journal of molecular sciences, 25(5) (5), English, International magazine

  Scientific journal


• Evaluating the Oxidation Rate of Reduced Ferredoxin in Arabidopsis thaliana Independent of Photosynthetic Linear Electron Flow: Plausible Activity of Ferredoxin-Dependent Cyclic Electron Flow around Photosystem I.

  Miho Ohnishi, Shu Maekawa, Shinya Wada, Kentaro Ifuku, Chikahiro Miyake

  The activity of ferredoxin (Fd)-dependent cyclic electron flow (Fd-CEF) around photosystem I (PSI) was determined in intact leaves of Arabidopsis thaliana. The oxidation rate of Fd reduced by PSI (vFd) and photosynthetic linear electron flow activity are simultaneously measured under actinic light illumination. The vFd showed a curved response to the photosynthetic linear electron flow activity. In the lower range of photosynthetic linear flow activity with plastoquinone (PQ) in a highly reduced state, vFd clearly showed a linear relationship with photosynthetic linear electron flow activity. On the other hand, vFd increased sharply when photosynthetic linear electron flow activity became saturated with oxidized PQ as the net CO2 assimilation rate increased. That is, under higher photosynthesis conditions, we observed excess vFd resulting in electron flow over photosynthetic linear electron flow. The situation in which excess vFd was observed was consistent with the previous Fd-CEF model. Thus, excess vFd could be attributed to the in vivo activity of Fd-CEF. Furthermore, the excess vFd was also observed in NAD(P)H dehydrogenase-deficient mutants localized in the thylakoid membrane. The physiological significance of the excessive vFd was discussed.

  Jul. 2023, International journal of molecular sciences, 24(15) (15), English, International magazine

  Scientific journal


• Behavior of Photosystems II and I Is Modulated Depending on N Partitioning to Rubisco in Mature Leaves Acclimated to Low N Levels and Senescent Leaves in Rice

  Yuji Suzuki, Kaho Ohsaki, Yuki Takahashi, Shinya Wada, Chikahiro Miyake, Amane Makino

  Feb. 2023, Plant & cell physiology, 64(1) (1), 55 - 63

  [Refereed]

  Scientific journal


• Effects of drought stress on the oxidation of the reaction center chlorophyll of photosystem I and grain yield in paddy-field grown rice plants

  Yuki Takahashi, Ko Noguchi, Kentaro Ifuku, Takayuki Sohtome, Takashi Nishimoto, Shinya Wada, Toshihiro Sato, Yuki Takegahara-Tamakawa, Chikahiro Miyake, Amane Makino, Yuji Suzuki

  2023, Soil Science and Plant Nutrition, 69(4) (4), 215 - 220

  Scientific journal


• Effects of simultaneous Rubisco, glyceraldehyde-3-phosphate dehydrogenase, and triosephosphate isomerase overexpression on photosynthesis in rice

  Yuji Suzuki, Mikuri Yamashita, Haruka Takada, Yuki Takegahara-Tamakawa, Chikahiro Miyake, Amane Makino

  2023, Soil Science and Plant Nutrition

  Scientific journal


• Higher Reduced State of Fe/S-Signals, with the Suppressed Oxidation of P700, Causes PSI Inactivation in Arabidopsis thaliana

  Riu Furutani, Shinya Wada, Kentaro Ifuku, Shu Maekawa, Chikahiro Miyake

  Environmental stress increases the risk of electron accumulation in photosystem I (PSI) of chloroplasts, which can cause oxygen (O2) reduction to superoxide radicals and decreased photosynthetic ability. We used three Arabidopsis thaliana lines: wild-type (WT) and the mutants pgr5hope1 and paa1-7/pox1. These lines have different reduced states of iron/sulfur (Fe/S) signals, including Fx, FA/FB, and ferredoxin, the electron carriers at the acceptor side of PSI. In the dark, short-pulse light was repetitively illuminated to the intact leaves of the plants to provide electrons to the acceptor side of PSI. WT and pgr5hope1 plants showed full reductions of Fe/S during short-pulse light and PSI inactivation. In contrast, paa1-7/pox1 showed less reduction of Fe/S and its PSI was not inactivated. Under continuous actinic-light illumination, pgr5hope1 showed no P700 oxidation with higher Fe/S reduction due to the loss of photosynthesis control and PSI inactivation. These results indicate that the accumulation of electrons at the acceptor side of PSI may trigger the production of superoxide radicals. P700 oxidation, responsible for the robustness of photosynthetic organisms, participates in reactive oxygen species suppression by oxidizing the acceptor side of PSI.

  Corresponding, MDPI AG, Dec. 2022, Antioxidants, 12(1) (1), 21 - 21

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Tight relationship between two photosystems is robust in rice leaves under various nitrogen conditions

  Hiroshi Ozaki, Yusuke Mizokami, Daisuke Sugiura, Takayuki Sohtome, Chikahiro Miyake, Hidemitsu Sakai, Ko Noguchi

  Springer Science and Business Media LLC, Dec. 2022, Journal of Plant Research, 136(2) (2), 201 - 210

  [Refereed]

  Scientific journal


• Order-of-magnitude enhancement in photocurrent generation of Synechocystis sp. PCC 6803 by outer membrane deprivation

  Shoko Kusama, Seiji Kojima, Ken Kimura, Ginga Shimakawa, Chikahiro Miyake, Kenya Tanaka, Yasuaki Okumura, Shuji Nakanishi

  Abstract Biophotovoltaics (BPV) generates electricity from reducing equivalent(s) produced by photosynthetic organisms by exploiting a phenomenon called extracellular electron transfer (EET), where reducing equivalent(s) is transferred to external electron acceptors. Although cyanobacteria have been extensively studied for BPV because of their high photosynthetic activity and ease of handling, their low EET activity poses a limitation. Here, we show an order-of-magnitude enhancement in photocurrent generation of the cyanobacterium Synechocystis sp. PCC 6803 by deprivation of the outer membrane, where electrons are suggested to stem from pathway(s) downstream of photosystem I. A marked enhancement of EET activity itself is verified by rapid reduction of exogenous electron acceptor, ferricyanide. The extracellular organic substances, including reducing equivalent(s), produced by this cyanobacterium serve as respiratory substrates for other heterotrophic bacteria. These findings demonstrate that the outer membrane is a barrier that limits EET. Therefore, depriving this membrane is an effective approach to exploit the cyanobacterial reducing equivalent(s).

  Springer Science and Business Media LLC, Dec. 2022, Nature Communications, 13(1) (1)

  [Refereed]

  Scientific journal


• Overexpression of Chloroplast Triosephosphate Isomerase Marginally Improves Photosynthesis at Elevated CO2 Levels in Rice

  Yuji Suzuki, Mizuki Shiina, Yuki Takegahara-Tamakawa, Chikahiro Miyake, Amane Makino

  Oct. 2022, Plant and Cell Physiology, 63(10) (10), 1500 - 1509

  [Refereed]

  Scientific journal


• The ability of P700 oxidation in photosystem I reflects chilling stress tolerance in cucumber.

  Ko Takeuchi, Yufen Che, Takeshi Nakano, Chikahiro Miyake, Kentaro Ifuku

  Low temperature inhibits photosynthesis and negatively affects plant growth. Cucumber (Cucumis sativus L.) is a chilling-sensitive plant, and its greenhouse production requires considerable energy during the winter. Therefore, a useful stress marker for selecting chilling-tolerant cucumber cultivars is desirable. In this study, we evaluated chilling-stress damage in different cucumber cultivars by measuring photosynthetic parameters. The majority of cultivars showed decreases in the quantum yield of photosystem (PS) II [Fv/Fm and Y(II)] and the quantity of active PS I (Pm) after chilling stress. In contrast, Y(ND)-the ratio of the oxidized state of PSI reaction center chlorophyll P700 (P700+)-differed among cultivars and was perfectly inversely correlated with Y(NA)-the ratio of the non-photooxidizable P700. It has been known that P700+ accumulates under stress conditions and protects plants to suppress the generation of reactive oxygen species. In fact, cultivars unable to induce Y(ND) after chilling stress showed growth retardation with reductions in chlorophyll content and leaf area. Therefore, Y(ND) can be a useful marker to evaluate chilling-stress tolerance in cucumber.

  Sep. 2022, Journal of plant research, 135(5) (5), 681 - 692, English, Domestic magazine

  [Refereed]

  Scientific journal


• NADPH production in dark stages is critical for cyanobacterial photocurrent generation: a study using mutants deficient in oxidative pentose phosphate pathway.

  Jiro Hatano, Shoko Kusama, Kenya Tanaka, Ayaka Kohara, Chikahiro Miyake, Shuji Nakanishi, Ginga Shimakawa

  Live cyanobacteria and algae integrated onto an extracellular electrode can generate a light-induced current (i.e., a photocurrent). Although the photocurrent is expected to be correlated with the redox environment of the photosynthetic cells, the relationship between the photocurrent and the cellular redox state is poorly understood. Here, we investigated the effect of the reduced nicotinamide adenine dinucleotide phosphate [NADP(H)] redox level of cyanobacterial cells (before light exposure) on the photocurrent using several mutants (Δzwf, Δgnd, and ΔglgP) deficient in the oxidative pentose phosphate (OPP) pathway, which is the metabolic pathway that produces NADPH in darkness. The NAD(P)H redox level and photocurrent in the cyanobacterium Synechocystis sp. PCC 6803 were measured noninvasively. Dysfunction of the OPP pathway led to oxidation of the photosynthetic NADPH pool in darkness. In addition, photocurrent induction was retarded and the current density was lower in Δzwf, Δgnd, and ΔglgP than in wild-type cells. Exogenously added glucose compensated the phenotype of ΔglgP and drove the OPP pathway in the mutant, resulting in an increase in the photocurrent. The results indicated that NADPH accumulated by the OPP pathway before illumination is a key factor for the generation of a photocurrent. In addition, measuring the photocurrent can be a non-invasive approach to estimate the cellular redox level related to NADP(H) pool in cyanobacteria.

  Aug. 2022, Photosynthesis research, 153(1-2) (1-2), 113 - 120, English, International magazine

  [Refereed]

  Scientific journal


• Dissection of respiratory and cyclic electron transport in Synechocystis sp. PCC 6803.

  Shoko Kusama, Chikahiro Miyake, Shuji Nakanishi, Ginga Shimakawa

  Cyclic electron transport (CET) is an attractive hypothesis for regulating photosynthetic electron transport and producing the additional ATP in oxygenic phototrophs. The concept of CET has been established in the last decades, and it is proposed to function in the progenitor of oxygenic photosynthesis, cyanobacteria. The in vivo activity of CET is frequently evaluated either from the redox state of the reaction center chlorophyll in photosystem (PS) I, P700, in the absence of PSII activity or by comparing PSI and PSII activities through the P700 redox state and chlorophyll fluorescence, respectively. The evaluation of CET activity, however, is complicated especially in cyanobacteria, where CET shares the intersystem chain, including plastoquinone, cytochrome b6/f complex, plastocyanin, and cytochrome c6, with photosynthetic linear electron transport (LET) and respiratory electron transport (RET). Here we sought to distinguish the in vivo electron transport rates in RET and CET in the cyanobacterium Synechocystis sp. PCC 6803. The reduction rate of oxidized P700 (P700+) decreased to less than 10% when PSII was inhibited, indicating that PSII is the dominant electron source to PSI but P700+ is also reduced by electrons derived from other sources. The oxidative pentose phosphate (OPP) pathway functions as the dominant electron source for RET, which was found to be inhibited by glycolaldehyde (GA). In the condition where the OPP pathway and respiratory terminal oxidases were inhibited by GA and KCN, the P700+ reduction rate was less than 1% of that without any inhibitors. This study indicate that the electron transport to PSI when PSII is inhibited is dominantly derived from the OPP pathway in Synechocystis sp. PCC 6803.

  Jul. 2022, Journal of plant research, 135(4) (4), 555 - 564, English, Domestic magazine

  [Refereed]

  Scientific journal


• Identification of Twelve Different Mineral Deficiencies in Hydroponically Grown Sunflower Plants on the Basis of Short Measurements of the Fluorescence and P700 Oxidation/Reduction Kinetics

  Gert Schansker, Miho Ohnishi, Riu Furutani, Chikahiro Miyake

  The photosynthetic electron transport chain is mineral rich. Specific mineral deficiencies can modify the electron transport chain specifically. Here, it is shown that on the basis of 2 short Chl fluorescence and P700⁺ measurements (approx. 1 s each), it is possible to discriminate between 10 out of 12 different mineral deficiencies: B, Ca, Cu, Fe, K, Mg, Mn, Mo, N, P, S, and Zn. B- and Mo-deficient plants require somewhat longer measurements to detect the feedback inhibition they induce. Eight out of twelve deficiencies mainly affect PS I and NIR measurements are, therefore, very important for this analysis. In Cu- and P-deficient plants, electron flow from the plastoquinone pool to PS I, is affected. In the case of Cu-deficiency due to the loss of plastocyanin and in the case of P-deficiency probably due to a fast and strong generation of Photosynthetic Control. For several Ca-, K-, and Zn-deficient plant species, higher levels of reactive oxygen species have been measured in the literature. Here, it is shown that this not only leads to a loss of Pm (maximum P700 redox change) reflecting a lower PS I content, but also to much faster P700⁺ re-reduction kinetics during the I₂-P (~30–200 ms) fluorescence rise phase. The different mineral deficiencies affect the relation between the I₂-P and P700⁺ kinetics in different ways and this is used to discuss the nature of the relationship between these two parameters.

  Corresponding, Frontiers Media SA, Jun. 2022, Frontiers in Plant Science, 13

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Effects of suppression of chloroplast phosphoglycerate kinase on photosynthesis in rice

  Yuji Suzuki, Yume Konno, Yuki Takegahara-Tamakawa, Chikahiro Miyake, Amane Makino

  Springer Science and Business Media LLC, May 2022, Photosynthesis Research, 153(1-2) (1-2), 83 - 91

  [Refereed]

  Scientific journal


• Suppression of chloroplast triose phosphate isomerase evokes inorganic phosphate-limited photosynthesis in rice

  Yuji Suzuki, Keiki Ishiyama, Dong-Kyung Yoon, Yuki Takegahara-Tamakawa, Eri Kondo, Mao Suganami, Shinya Wada, Chikahiro Miyake, Amane Makino

  Abstract The availability of inorganic phosphate (Pi) for ATP synthesis is thought to limit photosynthesis at elevated [CO2] when Pi regeneration via sucrose or starch synthesis is limited. We report here another mechanism for the occurrence of Pi-limited photosynthesis caused by insufficient capacity of chloroplast triose phosphate isomerase (cpTPI). In cpTPI-antisense transgenic rice (Oryza sativa) plants with 55%–86% reductions in cpTPI content, CO2 sensitivity of the rate of CO2 assimilation (A) decreased and even reversed at elevated [CO2]. The pool sizes of the Calvin–Benson cycle metabolites from pentose phosphates to 3-phosphoglycerate increased at elevated [CO2], whereas those of ATP decreased. These phenomena are similar to the typical symptoms of Pi-limited photosynthesis, suggesting sufficient capacity of cpTPI is necessary to prevent the occurrence of Pi-limited photosynthesis and that cpTPI content moderately affects photosynthetic capacity at elevated [CO2]. As there tended to be slight variations in the amounts of total leaf-N depending on the genotypes, relationships between A and the amounts of cpTPI were examined after these parameters were expressed per unit amount of total leaf-N (A/N and cpTPI/N, respectively). A/N at elevated [CO2] decreased linearly as cpTPI/N decreased before A/N sharply decreased, owing to further decreases in cpTPI/N. Within this linear range, decreases in cpTPI/N by 80% led to decreases up to 27% in A/N at elevated [CO2]. Thus, cpTPI function is crucial for photosynthesis at elevated [CO2].

  Oxford University Press (OUP), Mar. 2022, Plant Physiology, 188(3) (3), 1550 - 1562

  [Refereed]

  Scientific journal


• The difficulty of estimating the electron transport rate at photosystem I

  Riu Furutani, Miho Ohnishi, Yuki Mori, Shinya Wada, Chikahiro Miyake

  Corresponding, Springer Science and Business Media LLC, Nov. 2021, Journal of Plant Research

  [Refereed]

  Scientific journal


• Identification of a Novel Mutation Exacerbated the PSI Photoinhibition in pgr5/pgrl1 Mutants; Caution for Overestimation of the Phenotypes in Arabidopsis pgr5-1 Mutant

  Shinya Wada, Katsumi Amako, Chikahiro Miyake

  PSI photoinhibition is usually avoided through P700 oxidation. Without this protective mechanism, excess light represents a potentially lethal threat to plants. PGR5 is suggested to be a major component of cyclic electron transport around PSI and is important for P700 oxidation in angiosperms. The known Arabidopsis PGR5 deficient mutant, pgr5-1, is incapable of P700 oxidation regulation and has been used in numerous photosynthetic studies. However, here it was revealed that pgr5-1 was a double mutant with exaggerated PSI photoinhibition. pgr5-1 significantly reduced growth compared to the newly isolated PGR5 deficient mutant, pgr5hope1. The introduction of PGR5 into pgr5-1 restored P700 oxidation regulation, but remained a pale-green phenotype, indicating that pgr5-1 had additional mutations. Both pgr5-1 and pgr5hope1 tended to cause PSI photoinhibition by excess light, but pgr5-1 exhibited an enhanced reduction in PSI activity. Introducing AT2G17240, a candidate gene for the second mutation into pgr5-1 restored the pale-green phenotype and partially restored PSI activity. Furthermore, a deficient mutant of PGRL1 complexing with PGR5 significantly reduced PSI activity in the double-deficient mutant with AT2G17240. From these results, we concluded that AT2G17240, named PSI photoprotection 1 (PTP1), played a role in PSI photoprotection, especially in PGR5/PGRL1 deficient mutants.

  MDPI AG, Oct. 2021, Cells, 10(11) (11), 2884 - 2884

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• A synthetic phytosiderophore analog, proline-2′-deoxymugineic acid, is efficiently utilized by dicots

  Daisei Ueno, Yuta Ito, Miho Ohnishi, Chikahiro Miyake, Takayuki Sohtome, Motofumi Suzuki

  Abstract Purpose Phytosiderophores (PS) from grasses solubilize sparingly soluble iron (Fe), and the resultant PS-Fe is an Fe source even for dicots. Recently, the synthetic PS proline-2′-deoxymugineic acid (PDMA) has been developed as a moderately biodegradable Fe fertilizer for grasses. We aimed to investigate whether PDMA-Fe is also a good Fe source for dicots. Methods The availability of PDMA-Fe to cucumber was evaluated in a calcareous substrate and hydroponic cultures at pH 7.0–9.0 by determining chlorophyll level, PSII activity, and Fe uptake. EDDHA-Fe, EDTA-Fe, and citrate-Fe were used as controls. The reducibility of Fe chelates by roots was measured to determine the mechanism underlying differences in availability. Expressions of Fe deficiency-inducible genes were analyzed to estimate the Fe status in plants. Results The application of PDMA-Fe and EDDHA-Fe to a calcareous substrate reduced Fe-deficient chlorosis to a similar extent; however, the shoot Fe concentration was higher in the PDMA-Fe treatment. In the hydroponic culture, the availability of PDMA-Fe was higher than that of the other chelates at all pH levels, and this was confirmed by higher PSII activity and lower expression of Fe deficiency-inducible genes. The reducibility assay revealed that the reduction level of PDMA-Fe was greater than that of EDTA-Fe and citrate-Fe under alkaline pH. Conclusions PDMA-Fe is utilized by cucumber roots more efficiently than traditional synthetic chelates in both calcareous substrate and hydroponic cultures. The higher availability of PDMA-Fe may be attributed to its higher reducibility. Our findings suggest that PDMA-Fe could be a good Fe fertilizer for dicots.

  Springer Science and Business Media LLC, Sep. 2021, Plant and Soil, 469(1-2) (1-2), 123 - 134

  [Refereed]

  Scientific journal


• 9 イネにおける内在的なCO₂固定反応効率の変動と光呼吸によるP700 酸化誘導（関西支部講演会 2020年度支部講演会）

  古谷 吏侑, 牧野 周, 鈴木 雄二, 嶋川 銀河, 和田 慎也, 三宅 親弘

  一般社団法人 日本土壌肥料学会, Sep. 2021, 日本土壌肥料学会講演要旨集, 67, 220 - 220, Japanese


• Photosynthetic Parameters Show Specific Responses to Essential Mineral Deficiencies

  Miho Ohnishi, Riu Furutani, Takayuki Sohtome, Takeshi Suzuki, Shinya Wada, Soma Tanaka, Kentaro Ifuku, Daisei Ueno, Chikahiro Miyake

  In response to decreases in the assimilation efficiency of CO2, plants oxidize the reaction center chlorophyll (P700) of photosystem I (PSI) to suppress reactive oxygen species (ROS) production. In hydro-cultured sunflower leaves experiencing essential mineral deficiencies, we analyzed the following parameters that characterize PSI and PSII: (1) the reduction-oxidation states of P700 [Y(I), Y(NA), and Y(ND)]; (2) the relative electron flux in PSII [Y(II)]; (3) the reduction state of the primary electron acceptor in PSII, QA (1 − qL); and (4) the non-photochemical quenching of chlorophyll fluorescence (NPQ). Deficiency treatments for the minerals N, P, Mn, Mg, S, and Zn decreased Y(II) with an increase in the oxidized P700 [Y(ND)], while deficiencies for the minerals K, Fe, Ca, B, and Mo decreased Y(II) without an increase in Y(ND). During the induction of photosynthesis, the above parameters showed specific responses to each mineral. That is, we could diagnose the mineral deficiency and identify which mineral affected the photosynthesis parameters.

  Corresponding, MDPI AG, Jun. 2021, Antioxidants, 10(7) (7), 996 - 996

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Photosynthetic Linear Electron Flow Drives CO2 Assimilation in Maize Leaves.

  Ginga Shimakawa, Chikahiro Miyake

  Photosynthetic organisms commonly develop the strategy to keep the reaction center chlorophyll of photosystem I, P700, oxidized for preventing the generation of reactive oxygen species in excess light conditions. In photosynthesis of C4 plants, CO2 concentration is kept at higher levels around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) by the cooperation of the mesophyll and bundle sheath cells, which enables them to assimilate CO2 at higher rates to survive under drought stress. However, the regulatory mechanism of photosynthetic electron transport for P700 oxidation is still poorly understood in C4 plants. Here, we assessed gas exchange, chlorophyll fluorescence, electrochromic shift, and near infrared absorbance in intact leaves of maize (a NADP-malic enzyme C4 subtype species) in comparison with mustard, a C3 plant. Instead of the alternative electron sink due to photorespiration in the C3 plant, photosynthetic linear electron flow was strongly suppressed between photosystems I and II, dependent on the difference of proton concentration across the thylakoid membrane (ΔpH) in response to the suppression of CO2 assimilation in maize. Linear relationships among CO2 assimilation rate, linear electron flow, P700 oxidation, ΔpH, and the oxidation rate of ferredoxin suggested that the increase of ΔpH for P700 oxidation was caused by the regulation of proton conductance of chloroplast ATP synthase but not by promoting cyclic electron flow. At the scale of intact leaves, the ratio of PSI to PSII was estimated almost 1:1 in both C3 and C4 plants. Overall, the photosynthetic electron transport was regulated for P700 oxidation in maize through the same strategies as in C3 plants only except for the capacity of photorespiration despite the structural and metabolic differences in photosynthesis between C3 and C4 plants.

  Corresponding, May 2021, International journal of molecular sciences, 22(9) (9), English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Quantification of NAD(P)H in cyanobacterial cells by a phenol extraction method

  Kenya Tanaka, Ginga Shimakawa, Hiro Tabata, Shoko Kusama, Chikahiro Miyake, Shuji Nakanishi

  Abstract In photosynthetic organisms, it is recognized that the intracellular redox ratio of NADPH is regulated within an appropriate range for the cooperative function of a wide variety of physiological processes. However, despite its importance, there is large variability in the values of the NADPH fraction [NADPH/(NADPH + NADP⁺)] quantitatively estimated to date. In the present study, the light response of the NADPH fraction was investigated by applying a novel NADP(H) extraction method using phenol / chloroform / isoamyl alcohol (PCI) in the cyanobacterium Synechocystis sp. PCC 6803. The light response of NADP(H) observed using PCI extraction was qualitatively consistent with the NAD(P)H fluorescence time course measured in vivo. Moreover, the results obtained by PCI extraction and the fluorescence-based methods were also consistent in a mutant lacking the ability to oxidize NAD(P)H in the respiratory chain, and exhibiting a unique NADPH light response. These observations indicate that the PCI extraction method allowed quantitative determination of NADP(H) redox. Notably, the PCI extraction method showed that not all NADP(H) was oxidized or reduced by light–dark transition. Specifically, the fraction of NADPH was 42% in the dark-adapted cell, and saturated at 68% in light conditions.

  Springer Science and Business Media LLC, May 2021, Photosynthesis Research, 148(1-2) (1-2), 57 - 66

  [Refereed]

  Scientific journal


• Effects of co-overproduction of Rubisco and chloroplast glyceraldehyde-3-phosphate dehydrogenase on photosynthesis in rice

  Yuji Suzuki, Keiki Ishiyama, Ayaka Cho, Yuki Takegahara-Tamakawa, Shinya Wada, Chikahiro Miyake, Amane Makino

  Informa UK Limited, Apr. 2021, Soil Science and Plant Nutrition, 1 - 5

  [Refereed]

  Scientific journal


• Photochemistry of Photosystems II and I in Rice Plants Grown under Different N Levels at Normal and High Temperature

  Yuki Takahashi, Shinya Wada, Ko Noguchi, Chikahiro Miyake, Amane Makino, Yuji Suzuki

  Although N levels affect leaf photosynthetic capacity, the effects of N levels on the photochemistry of photosystems II and I (PSII and PSI, respectively) are not well-understood. In the present study, we examined this aspect in rice (Oryza sativa L. ‘Hitomebore’) plants grown under three different N levels at normal or high temperatures that can occur during rice culture and do not severely suppress photosynthesis. At both growth temperatures, the quantum efficiency of PSII [Y(II)] and the fraction of the primary quinone electron acceptor in its oxidized state were positively correlated with the amount of total leaf-N, whereas the quantum yields of non-photochemical quenching and donor-side limitation of PSI [Y(ND)] were negatively correlated with the amount of total leaf-N. These changes in PSII and PSI parameters were strongly correlated with each other. Growth temperatures scarcely affected these relationships. These results suggest that the photochemistry of PSII and PSI is coordinately regulated primarily depending on the amount of total leaf-N. When excess light energy occurs in low N-acclimated plants, oxidation of the reaction center chlorophyll of PSI is thought to be stimulated to protect PSI from excess light energy. It is also suggested that PSII and PSI normally operate at high temperature used in the present study. In addition, as the relationships between Y(II) and Y(ND) were found to be almost identical to those observed in osmotically stressed rice plants, common regulation is thought to be operative when excess light energy occurs due to different causes.

  Oxford University Press (OUP), Feb. 2021, Plant and Cell Physiology

  [Refereed]

  Scientific journal


• Evolutive differentiation between alga- and plant-type plastid terminal oxidase: Study of plastid terminal oxidase PTOX isoforms in Marchantia polymorpha

  Marine Messant, Ginga Shimakawa, François Perreau, Chikahiro Miyake, Anja Krieger-Liszkay

  Elsevier BV, Jan. 2021, Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1862(1) (1), 148309 - 148309

  [Refereed]

  Scientific journal


• Oxidation of the reaction center chlorophyll of photosystem I is induced via close cooperation of photosystems II and I with progress of drought stress in soybean seedlings

  Yuji Suzuki, Kota Nagao, Yuki Takahashi, Chikahiro Miyake, Amane Makino

  2021, Soil Science and Plant Nutrition, 67(6) (6), 662 - 669

  [Refereed]

  Scientific journal


• Physiological Roles of Flavodiiron Proteins and Photorespiration in the Liverwort Marchantia polymorpha.

  Ginga Shimakawa, Hitomi Hanawa, Shinya Wada, Guy T Hanke, Yusuke Matsuda, Chikahiro Miyake

  Against the potential risk in oxygenic photosynthesis, that is, the generation of reactive oxygen species, photosynthetic electron transport needs to be regulated in response to environmental fluctuations. One of the most important regulations is keeping the reaction center chlorophyll (P700) of photosystem I in its oxidized form in excess light conditions. The oxidation of P700 is supported by dissipating excess electrons safely to O2, and we previously found that the molecular mechanism of the alternative electron sink is changed from flavodiiron proteins (FLV) to photorespiration in the evolutionary history from cyanobacteria to plants. However, the overall picture of the regulation of photosynthetic electron transport is still not clear in bryophytes, the evolutionary intermediates. Here, we investigated the physiological roles of FLV and photorespiration for P700 oxidation in the liverwort Marchantia polymorpha by using the mutants deficient in FLV (flv1) at different O2 partial pressures. The effective quantum yield of photosystem II significantly decreased at 2kPa O2 in flv1, indicating that photorespiration functions as the electron sink. Nevertheless, it was clear from the phenotype of flv1 that FLV was dominant for P700 oxidation in M. polymorpha. These data suggested that photorespiration has yet not replaced FLV in functioning for P700 oxidation in the basal land plant probably because of the lower contribution to lumen acidification, compared with FLV, as reflected in the results of electrochromic shift analysis.

  Corresponding, 2021, Frontiers in plant science, 12, 668805 - 668805, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Characterization of Light-Enhanced Respiration in Cyanobacteria.

  Ginga Shimakawa, Ayaka Kohara, Chikahiro Miyake

  In eukaryotic algae, respiratory O2 uptake is enhanced after illumination, which is called light-enhanced respiration (LER). It is likely stimulated by an increase in respiratory substrates produced during photosynthetic CO2 assimilation and function in keeping the metabolic and redox homeostasis in the light in eukaryotic cells, based on the interactions among the cytosol, chloroplasts, and mitochondria. Here, we first characterize LER in photosynthetic prokaryote cyanobacteria, in which respiration and photosynthesis share their metabolisms and electron transport chains in one cell. From the physiological analysis, the cyanobacterium Synechocystis sp. PCC 6803 performs LER, similar to eukaryotic algae, which shows a capacity comparable to the net photosynthetic O2 evolution rate. Although the respiratory and photosynthetic electron transports share the interchain, LER was uncoupled from photosynthetic electron transport. Mutant analyses demonstrated that LER is motivated by the substrates directly provided by photosynthetic CO2 assimilation, but not by glycogen. Further, the light-dependent activation of LER was observed even with exogenously added glucose, implying a regulatory mechanism for LER in addition to the substrate amounts. Finally, we discuss the physiological significance of the large capacity of LER in cyanobacteria and eukaryotic algae compared to those in plants that normally show less LER.

  Corresponding, Dec. 2020, International journal of molecular sciences, 22(1) (1), English, International magazine

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Intrinsic Fluctuations in Transpiration Induce Photorespiration to Oxidize P700 in Photosystem I

  Riu Furutani, Amane Makino, Yuij Suzuki, Shinya Wada, Ginga Shimakawa, Chikahiro Miyake

  Upon exposure to environmental stress, the primary electron donor in photosystem I (PSI), P700, is oxidized to suppress the production of reactive oxygen species that could oxidatively inactivate the function of PSI. The illumination of rice leaves with actinic light induces intrinsic fluctuations in the opening and closing of stomata, causing the net CO2 assimilation rate to fluctuate. We examined the effects of these intrinsic fluctuations on electron transport reactions. Under atmospheric O2 conditions (21 kPa), the effective quantum yield of photosystem II (PSII) (Y(II)) remained relatively high while the net CO2 assimilation rate fluctuated, which indicates the function of alternative electron flow. By contrast, under low O2 conditions (2 kPa), Y(II) fluctuated. These results suggest that photorespiration primarily drove the alternative electron flow. Photorespiration maintained the oxidation level of ferredoxin (Fd) throughout the fluctuation of the net CO2 assimilation rate. Moreover, the relative activity of photorespiration was correlated with both the oxidation level of P700 and the magnitude of the proton gradient across the thylakoid membrane in 21 kPa O2 conditions. These results show that photorespiration oxidized P700 by stimulating the proton gradient formation when CO2 assimilation was suppressed by stomatal closure.

  Corresponding, MDPI AG, Dec. 2020, Plants, 9(12) (12), 1761 - 1761

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Overproduction of Chloroplast Glyceraldehyde-3-Phosphate Dehydrogenase Improves Photosynthesis Slightly under Elevated [CO2] Conditions in Rice

  Yuji Suzuki, Keiki Ishiyama, Misaki Sugawara, Yuka Suzuki, Eri Kondo, Yuki Takegahara-Tamakawa, Dong-Kyung Yoon, Mao Suganami, Shinya Wada, Chikahiro Miyake, Amane Makino

  Chloroplast glyceraldehyde-3-phosphate dehydrogenase (GAPDH) limits the regeneration of ribulose 1,5-bisphosphate (RuBP) in the Calvin-Benson cycle. However, it does not always limit the rate of CO2 assimilation. In the present study, the effects of overproduction of GAPDH on the rate of CO2 assimilation under elevated [CO2] conditions, where the capacity for RuBP regeneration limits photosynthesis, were examined in transgenic rice (Oryza sativa). GAPDH activity was increased to 6.3- to 9.1-fold of the wild-type levels by co-overexpression of the GAPDH genes, GAPA and GAPB. In the transgenic rice plants, the rate of CO2 assimilation under elevated [CO2] conditions increased by approximately 10%, whereas that under normal and low [CO2] conditions was not affected. These results indicate that overproduction of GAPDH is effective in improving photosynthesis under elevated [CO2] conditions, although its magnitude was relatively small. However, biomass production of the transgenic rice plants was not greater than that in wild-type plants under elevated [CO2] conditions, although starch content tended to increase marginally.

  Oxford University Press (OUP), Dec. 2020, Plant and Cell Physiology

  [Refereed]

  Scientific journal


• Identification of the electron donor to flavodiiron proteins in Synechocystis sp. PCC 6803 by in vivo spectroscopy

  Pierre Sétif, Ginga Shimakawa, Anja Krieger-Liszkay, Chikahiro Miyake

  Elsevier BV, Oct. 2020, Biochimica et Biophysica Acta (BBA) - Bioenergetics, 1861(10) (10), 148256 - 148256

  [Refereed]

  Scientific journal


• 4-1-28 カルビンサイクル酵素グリセルアルデヒド-3-リン酸デヒドロゲナーゼおよびトリオースリン酸イソメラーゼの遺伝子組換えがイネ葉の光合成に及ぼす影響（4-1 植物の多量栄養素 2020年度岡山大会）

  鈴木 雄二, 石山 敬貴, 菅原 水彩季, 鈴木 優佳, 玉川 夕紀, 和田 慎也, 菅波 眞央, 近藤 依里, 三宅 親弘, 牧野 周

  一般社団法人 日本土壌肥料学会, Sep. 2020, 日本土壌肥料学会講演要旨集, 66, 46 - 46, Japanese


• Photoprotection mechanisms under different CO2 regimes during photosynthesis in a green alga Chlorella variabilis.

  Yoshifumi Ueno, Ginga Shimakawa, Shimpei Aikawa, Chikahiro Miyake, Seiji Akimoto

  Oxygenic photosynthesis converts light energy into chemical energy via electron transport and assimilates CO2 in the Calvin-Benson cycle with the chemical energy. Thus, high light and low CO2 conditions induce the accumulation of electrons in the photosynthetic electron transport system, resulting in the formation of reactive oxygen species. To prevent the accumulation of electrons, oxygenic photosynthetic organisms have developed photoprotection mechanisms, including non-photochemical quenching (NPQ) and alternative electron flow (AEF). There are diverse molecular mechanisms underlying NPQ and AEF, and the corresponding molecular actors have been identified and characterized using a model green alga Chlamydomonas reinhardtii. In contrast, detailed information about the photoprotection mechanisms is lacking for other green algal species. In the current study, we examined the photoprotection mechanisms responsive to CO2 in the green alga Chlorella variabilis by combining the analyses of pulse-amplitude-modulated fluorescence, O2 evolution, and the steady-state and time-resolved fluorescence spectra. Under the CO2-limited condition, ΔpH-dependent NPQ occurred in photosystems I and II. Moreover, O2-dependent AEF was also induced. Under the CO2-limited condition with carbon supplementation, NPQ was relaxed and light-harvesting chlorophyll-protein complex II was isolated from both photosystems. In C. variabilis, the O2-dependent AEF and the mechanisms that instantly convert the light-harvesting functions of both photosystems may be important for maintaining efficient photosynthetic activities under various CO2 conditions.

  Jun. 2020, Photosynthesis research, 144(3) (3), 397 - 407, English, International magazine

  [Refereed]

  Scientific journal


• Molecular Mechanism of Oxidation of P700 and Suppression of ROS Production in Photosystem I in Response to Electron-Sink Limitations in C3 Plants

  Chikahiro Miyake

  Photosynthesis fixes CO2 and converts it to sugar, using chemical-energy compounds of both NADPH and ATP, which are produced in the photosynthetic electron transport system. The photosynthetic electron transport system absorbs photon energy to drive electron flow from Photosystem II (PSII) to Photosystem I (PSI). That is, both PSII and PSI are full of electrons. O2 is easily reduced to a superoxide radical (O2−) at the reducing side, i.e., the acceptor side, of PSI, which is the main production site of reactive oxygen species (ROS) in photosynthetic organisms. ROS-dependent inactivation of PSI in vivo has been reported, where the electrons are accumulated at the acceptor side of PSI by artificial treatments: exposure to low temperature and repetitive short-pulse (rSP) illumination treatment, and the accumulated electrons flow to O2, producing ROS. Recently, my group found that the redox state of the reaction center of chlorophyll P700 in PSI regulates the production of ROS: P700 oxidation suppresses the production of O2− and prevents PSI inactivation. This is why P700 in PSI is oxidized upon the exposure of photosynthesis organisms to higher light intensity and/or low CO2 conditions, where photosynthesis efficiency decreases. In this study, I introduce a new molecular mechanism for the oxidation of P700 in PSI and suppression of ROS production from the robust relationship between the light and dark reactions of photosynthesis. The accumulated protons in the lumenal space of the thylakoid membrane and the accumulated electrons in the plastoquinone (PQ) pool drive the rate-determining step of the P700 photo-oxidation reduction cycle in PSI from the photo-excited P700 oxidation to the reduction of the oxidized P700, thereby enhancing P700 oxidation.

  Corresponding, MDPI AG, Mar. 2020, Antioxidants, 9(3) (3), 230 - 230

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Photorespiration Enhances Acidification of the Thylakoid Lumen, Reduces the Plastoquinone Pool, and Contributes to the Oxidation of P700 at a Lower Partial Pressure of CO₂ in Wheat Leaves

  Shinya Wada, Yuji Suzuki, Chikahiro Miyake

  Corresponding, Mar. 2020, Plants

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• P700 oxidation suppresses the production of reactive oxygen species in photosystem I

  Riu Furutani, Kentaro Ifuku, Yuji Suzuki, Ko Noguchi, Ginga Shimakawa, Shinya Wada, Amane Makino, Takayuki Sohtome, Chikahiro Miyake

  Corresponding, Elsevier, 2020, Advances in Botanical Research, 151 - 176

  [Refereed]

  In book


• Photorespiration Coupled With CO2 Assimilation Protects Photosystem I From Photoinhibition Under Moderate Poly(Ethylene Glycol)-Induced Osmotic Stress in Rice.

  Shinya Wada, Chikahiro Miyake, Amane Makino, Yuji Suzuki

  Photorespiration coupled with CO2 assimilation is thought to act as a defense system against photoinhibition caused by osmotic stress. In the present study, we examined whether such a mechanism is operative for the protection of photosystem I (PSI) in rice (Oryza sativa L.) including transgenic plants with decreased and increased Rubisco content (RBCS-antisense and RBCS-sense plants, respectively). All plants were hydroponically grown and moderate osmotic stress was imposed using hydroponic culture solutions containing poly(ethylene glycol) (PEG) at 16% or 20% (w/v) for 2 d. In wild-type plants, the rates of CO2 assimilation (A) were significantly decreased by the PEG treatment, whereas the photorespiration activity estimated from the rates of electron transport in photosystem II (PSII) and A were not affected. The maximal quantum efficiency of PSII (Fv/Fm) and the maximal activity of PSI (Pm) were also not affected. In RBCS-antisense plants, A and the estimated photorespiration activity were considerably lower than those in wild-type plants in the presence or absence of the PEG treatment. Pm and both Fv/Fm and Pm decreased in the 16% PEG-treated and 20% PEG-treated RBCS-antisense plants, respectively. Thus, the decrease in Rubisco content led to the photoinhibition of PSI and PSII, indicating the importance of photorespiration coupled with CO2 assimilation for the protection of PSI from moderate PEG-induced osmotic stress. It was also shown that PSI was more sensitive to osmotic stress than PSII. In the PEG-treated wild-type and RBCS-antisense plants, osmotic-stress responses of the photosynthetic electron transport reactions upstream of PSI led to the oxidation of P700, which is thought to prevent PSI from over-reduction. Although such a defense system operated, it was not sufficient for the protection of PSI in RBCS-antisense plants. In addition, there were no large differences in the parameters measured between wild-type and RBCS-sense plants, as overproduction of Rubisco did not increase photorespiration activity.

  2020, Frontiers in plant science, 11, 1121 - 1121, English, International magazine

  [Refereed]

  Scientific journal


• 5 シロイヌナズナを用いた光酸化ストレス防御機構におけるFerredoxin:NADP⁺ oxidoreductasesの重要性（関西支部講演会）

  門田 かなえ, 嶋川 銀河, 三宅 親弘

  一般社団法人 日本土壌肥料学会, Sep. 2019, 日本土壌肥料学会講演要旨集, 65, 278 - 278, Japanese


• Oxidation of P700 Induces Alternative Electron Flow in Photosystem I in Wheat Leaves.

  Kanae Kadota, Riu Furutani, Amane Makino, Yuji Suzuki, Shinya Wada, Chikahiro Miyake

  Oxygen (O2)-evolving photosynthetic organisms oxidize the reaction center chlorophyll, P700, in photosystem I (PSI) to suppress the production of reactive oxygen species. The oxidation of P700 is accompanied by alternative electron flow in PSI (AEF-I), which is not required for photosynthetic linear electron flow (LEF). To characterize AEF-I, we compared the redox reactions of P700 and ferredoxin (Fd) during the induction of carbon dioxide (CO2) assimilation in wheat leaves, using dark-interval relaxation kinetics analysis. Switching on an actinic light (1000 μmol photons m-2 s-1) at ambient CO2 partial pressure of 40 Pa and ambient O2 partial pressure of 21 kPa gradually oxidized P700 (P700+) and enhanced the reduction rate of P700+ (vP700) and oxidation rate of reduced Fd (vFd). The vFd showed a positive linear relationship with an apparent photosynthetic quantum yield of PSII (Y[II]) originating at point zero; the redox turnover of Fd is regulated by LEF via CO2 assimilation and photorespiration. The vP700 also showed a positive linear relationship with Y(II), but the intercept was positive, not zero. That is, the electron flux in PSI included the electron flux in AEF-I in addition to that in LEF. This indicates that the oxidation of P700 induces AEF-I. We propose a possible mechanism underlying AEF-I and its physiological role in the mitigation of oxidative damage.

  Corresponding, Jun. 2019, Plants (Basel, Switzerland), 8(6) (6), English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Growth light environment changes the sensitivity of photosystem I photoinhibition by depending on common wheat cultivars

  Daisuke Takagi, HIroaki Ihara, Shigeo Takumi, Chikahiro Miyake

  Corresponding, Jun. 2019, Frontiers in Plant Science, 10, 686, English

  [Refereed]

  Scientific journal


• What Quantity of Photosystem I Is Optimum for Safe Photosynthesis?

  Ginga Shimakawa, Chikahiro Miyake

  PSI has the potential to generate reactive oxygen species and be oxidatively inactivated by the reactive oxygen species. The photo-oxidative damage of PSI (also called PSI photoinhibition) causes the inhibition of the plant growth and is a lethal event for plants. It has been reported that PSI photoinhibition does not occur as long as the reaction-center chlorophyll (P700) remains oxidized, even in excess light conditions. This process is termed P700 oxidation and is supported by various regulatory mechanisms and likely also by the stoichiometric quantities of photosynthetic apparatus. In this study, we assessed how decreased photochemically active PSI in Arabidopsis (Arabidopsis thaliana) affected a variety of photosynthetic parameters, including P700 oxidation. Inactivation of PSI was rapidly and selectively induced by repetitive short-pulse illumination. PSI photoinhibition correlated linearly with decreases in effective quantum yield of PSII and nonphotochemical quenching; however, the photosynthetic CO2 assimilation rate was less affected, as exemplified by ∼50% of the normal CO2 assimilation rate maintained with an 80% loss in PSI photochemical activity. In contrast, effective quantum yield of PSI was enhanced following PSI photoinhibition, mainly owing to a decrease in the electron donor-side limitation of PSI. Based on these results, we propose that the stoichiometric quantity of PSI is optimized to induce P700 oxidation for dissipating excess light energy in PSI, thus avoiding inhibition of photosynthetic CO2 assimilation caused by PSI photoinhibition.

  Corresponding, Apr. 2019, Plant physiology, 179(4) (4), 1479 - 1485, English, International magazine

  [Refereed]

  Scientific journal


• Responses of the Photosynthetic Electron Transport Reactions Stimulate the Oxidation of the Reaction Center Chlorophyll of Photosystem I, P700, under Drought and High Temperatures in Rice

  WADA SHINYA, TAKAGI DAISUKE, MIYAKE CHIKAHIRO, MAKINO AMANE, SUZUKI YUJI

  It is of interest how photosynthetic electron transport (PET) reactions respond to excess light energy caused by the combination of drought stress and high temperatures. Since such information is scarcely available for photosystem I (PSI), this question was explored in rice (Oryza sativa L.) plants subjected to drought stress, using culture solutions that contain poly(ethylene glycol) at different concentrations under two day/night temperature regimes. At 27/22 °C (day/night), drought stress led to the oxidation of the reaction center of the chlorophyll of PSI (P700), and also led to decreases in the quantum efficiencies of photosystem II (PSII) and PSI, and a reduction of the primary quinone electron acceptor of PSI. Such drought stress responses were wholly stimulated at 35/30 °C. These parameters were strongly correlated with each other and were minimally affected by temperature. These results indicate that the drought stress responses of the respective PET reactions are closely associated with each other in the oxidization of P700 and that such responses are stimulated at high temperatures. The underlying mechanisms of these phenomena were discussed. While P700 oxidation is thought to suppress reactive oxygen species (ROS) production, PSI photoinhibition was observed under severe stress conditions, implying that P700 oxidation is not sufficient for the protection of PSI under drought stress.

  MDPI, Apr. 2019, International Journal of Molecular Sciences, 20(9) (9), 2068, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Comparative analysis of strategies to prepare electron sinks in aquatic photoautotrophs

  Shimakawa Ginga, MURAKAMI AKIO, Niwa Kyosuke, Matsuda Yusuke, Wada Ayumi, MIyake Chikahiro

  Springer Science and Business Media LLC, Mar. 2019, Photosynthesis Research, 139(1-3) (1-3), 401 - 411, English

  [Refereed]

  Scientific journal


• Responses of the chloroplast glyoxalase system to high CO2 concentrations.

  Ginga SHIMAKAWA, Kentaro IFUKU, Yuji SUZUKI, Amane MAKINO, Kimitsune ISHIZAKI, Hiroshi FUKAYAMA, Ryutaro MORITA, Katsuhiko SAKAMOTO, Akiko NISHI, Chikahiro MIYAKE

  Dec. 2018, Bioscience, Biotechnology and Biochemistry, 82(12) (12), 2072 - 2083, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• VII-6 作物生産における酸化ストレス：傷害機構、耐性機構、危険予知による回避 内在的活性酸素生成を目的としたパルス法の確立と栽培環境診断への応用―P700酸化システムにもとづく活性酸素（ROS）診断の実用化―（シンポジウム，2018年度神奈川大会）

  瀬島 健裕, 高木 大輔, 嶋川 銀河, 釋 啓一郎, 塙 仁美, 三宅 親弘

  一般社団法人 日本土壌肥料学会, Aug. 2018, 日本土壌肥料学会講演要旨集, 64, 205, Japanese


• Changing frequency of fluctuating light reveals the molecular mechanism for P700 oxidation in plant leaves.

  Ginga Shimakawa, Chikahiro Miyake

  Natural sunlight exceeds the demand of photosynthesis such that it can cause plants to produce reactive oxygen species (ROS), which subsequently cause photo-oxidative damage. Because photosystem I (PSI) is a major source of ROS, plants actively maintain the reaction center chlorophyll of PSI(P700) oxidized under excessive light conditions to alleviate the ROS production. P700 oxidation is universally recognized in photosynthetic organisms as a physiological response to excessive light. However, it is still poorly understood how P700 oxidation is induced in response to fluctuating light with a variety of frequencies. Here, we investigated the relationships of photosynthetic parameters with P700 oxidation in Arabidopsis thaliana under a sine fluctuating light with different frequencies. As the photon flux density of the light increased, P700 was oxidized concurrently with the chlorophyll fluorescence parameter qL unless the electron acceptor side of PSI was limited. Conversely, we did not observe a proportional relationship of non-photochemical quenching with P700 oxidation. The mutant crr-2, which lacks chloroplast NADPH dehydrogenase, was impaired in P700 oxidation during light fluctuation at high, but not low frequency, unlike the pgrl1 mutant deficient in PGR5 and PGRL1 proteins, which could not oxidize P700 during light fluctuation at both high and low frequencies. Taken together, our findings suggested that the changing frequency of fluctuating light reveals the tracking performance of molecular mechanisms underlying P700 oxidation.

  Corresponding, Jul. 2018, Plant direct, 2(7) (7), e00073, English, International magazine

  [Refereed]

  Scientific journal


• Reduction-induced suppression of electron flow (RISE) is relieved by non-ATP-consuming electron flow in Synechococcus elongatus PCC 7942

  Ginga Shimakawa, Keiichiro Shaku, Chikahiro Miyake

  Corresponding, Frontiers Media S.A., May 2018, Frontiers in Microbiology, 9(MAY) (MAY), English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Antimycin A inhibits cytochrome b559-mediated cyclic electron flow within photosystem II

  Daisuke Takagi, Kentaro Ifuku, Taishi Nishimura, Chikahiro Miyake

  Springer Nature, May 2018, Photosynthesis Research, 139(1-3) (1-3), 487 - 498, English

  [Refereed]

  Scientific journal


• Respiratory terminal oxidases alleviate photo-oxidative damage in photosystem I during repetitive short-pulse illumination in Synechocystis sp. PCC 6803

  Ginga Shimakawa, Chikahiro Miyake

  Springer Netherlands, Mar. 2018, Photosynthesis Research, 1 - 10, English

  [Refereed]

  Scientific journal


• Oxidation of P700 Ensures Robust Photosynthesis.

  Ginga Shimakawa, Chikahiro Miyake

  In the light, photosynthetic cells can potentially suffer from oxidative damage derived from reactive oxygen species. Nevertheless, a variety of oxygenic photoautotrophs, including cyanobacteria, algae, and plants, manage their photosynthetic systems successfully. In the present article, we review previous research on how these photoautotrophs safely utilize light energy for photosynthesis without photo-oxidative damage to photosystem I (PSI). The reaction center chlorophyll of PSI, P700, is kept in an oxidized state in response to excess light, under high light and low CO2 conditions, to tune the light utilization and dissipate the excess photo-excitation energy in PSI. Oxidation of P700 is co-operatively regulated by a number of molecular mechanisms on both the electron donor and acceptor sides of PSI. The strategies to keep P700 oxidized are diverse among a variety of photoautotrophs, which are evolutionarily optimized for their ecological niche.

  Corresponding, 2018, Frontiers in plant science, 9, 1617 - 1617, English, International magazine

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Effects of genetic manipulation of the activity of photorespiration on the redox state of photosystem I and its robustness against excess light stress under CO₂-limited conditions in rice

  Shinya Wada, Yuji Suzuki, Daisuke Takagi, Chikahiro Miyake, Amane Makino

  Under CO2-limited conditions such as during stomatal closure, photorespiration is suggested to act as a sink for excess light energy and protect photosystem I (PSI) by oxidizing its reaction center chlorophyll P700. In this study, this issue was directly examined with rice (Oryza sativa L.) plants via genetic manipulation of the amount of Rubisco, which can be a limiting factor for photorespiration. At low [CO2] of 5 Pa that mimicked stomatal closure condition, the activity of photorespiration in transgenic plants with decreased Rubisco content (RBCS-antisense plants) markedly decreased, whereas the activity in transgenic plants with overproduction of Rubisco (RBCS-sense plants) was similar to that in wild-type plants. Oxidation of P700 was enhanced at [CO2] of 5 Pa in wild-type and RBCS-sense plants. PSI was not damaged by excess light stress induced by repetitive saturated pulse-light (rSP) in the presence of strong steady-state light. On the other hand, P700 was strongly reduced in RBCS-antisense plants at [CO2] of 5 Pa. PSI was also damaged by rSP illumination. These results indicate that oxidation of P700 and the robustness of PSI against excess light stress are hampered by the decreased activity of photorespiration as a result of genetic manipulation of Rubisco content. It is also suggested that overproduction of Rubisco does not enhance photorespiration as well as CO2 assimilation probably due to partial deactivation of Rubisco.

  2018, Photosynthesis Research, 137(3) (3), 431 - 441, English, International magazine

  [Refereed]

  Scientific journal


• PROTON GRADIENT REGULATION 5 supports linear electron flow to oxidize photosystem I

  Daisuke Takagi, Chikahiro Miyake

  Wiley, 2018, Physiologia Plantaruim, 164(3) (3), 337 - 348, English

  [Refereed]

  Scientific journal


• Light-harvesting strategy during CO2-dependent photosynthesis in the green alga Chlamydomonas reinhardtii

  Y. Ueno, G. Shimakawa, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  2018, J. Phys. Chem. Lett., 9, 1028 - 1033, English

  [Refereed]

  Scientific journal


• A Carbon Dioxide Limitation-Inducible Protein, ColA, Supports the Growth of Synechococcus sp PCC 7002

  Ginga Shimakawa, Satoru Watanabe, Chikahiro Miyake

  Dec. 2017, MARINE DRUGS, 15(12) (12), English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Diversity of strategies for escaping reactive oxygen species production within photosystem I among land plants: P700 oxidation system is prerequisite for alleviating photoinhibition in photosystem I

  Daisuke Takagi, Kimitsune Ishizaki, Hitomi Hanawa, Tomohito Mabuchi, Ginga Shimakawa, Hiroshi Yamamoto, Chikahiro Miyake

  Corresponding, Blackwell Publishing Ltd, Sep. 2017, Physiologia Plantarum, 161(1) (1), 56 - 74, English

  [Refereed]

  Scientific journal


• Land plants drive photorespiration as higher electron-sink: comparative study of post-illumination transient O-2-uptake rates from liverworts to angiosperms through ferns and gymnosperms

  Hitomi Hanawa, Kimitsune Ishizaki, Kana Nohira, Daisuke Takagi, Ginga Shimakawa, Takehiro Sejima, Keiichiro Shaku, Amane Makino, Chikahiro Miyake

  Sep. 2017, PHYSIOLOGIA PLANTARUM, 161(1) (1), 138 - 149, English

  [Refereed]

  Scientific journal


• Chloroplastic ATP synthase builds up proton motive force for preventing reactive oxygen species production in photosystem I

  TAKAGI DAISUKE, Amako Katsumi, Masaki Hashiguchi, Hidehiro Fukaki, Kimitsune Ishizaki, Tatsuaki Goh, Yoichiro Fukao, Yosuke Sano, Tetsuya Kurata, Taku Demura, Shinichiro Sawa, Chikahiro Miyake

  Apr. 2017, The Plant Journal, 91, 306 - 324, English

  [Refereed]

  Scientific journal


• The Liverwort, Marchantia, Drives Alternative Electron Flow Using a Flavodiiron Protein to Protect PSI

  Ginga Shimakawa, Kimitsune Ishizaki, Shigeyuki Tsukamoto, Moeko Tanaka, Takehiro Sejima, Chikahiro Miyake

  Mar. 2017, PLANT PHYSIOLOGY, 173(3) (3), 1636 - 1647, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Diverse strategies of O-2 usage for preventing photo-oxidative damage under CO2 limitation during algal photosynthesis

  Ginga Shimakawa, Yusuke Matsuda, Kensuke Nakajima, Masahiro Tamoi, Shigeru Shigeoka, Chikahiro Miyake

  Jan. 2017, SCIENTIFIC REPORTS, 7, 41022, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Oxidation of P700 in Photosystem I Is Essential for the Growth of Cyanobacteria

  Ginga Shimakawa, Keiichiro Shaku, Chikahiro Miyake

  Nov. 2016, PLANT PHYSIOLOGY, 172(3) (3), 1443 - 1450, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Photorespiration provides the chance of cyclic electron flow to operate for the redox-regulation of P700 in photosynthetic electron transport system of sunflower leaves

  Daisuke Takagi, Masaki Hashiguchi, Takehiro Sejima, Amane Makino, Chikahiro Miyake

  Sep. 2016, PHOTOSYNTHESIS RESEARCH, 129(3) (3), 279 - 290, English

  [Refereed]

  Scientific journal


• Reduction-Induced Suppression of Electron Flow (RISE) in the Photosynthetic Electron Transport System of Synechococcus elongatus PCC 7942

  Keiichiro Shaku, Ginga Shimakawa, Masaki Hashiguchi, Chikahiro Miyake

  Jul. 2016, PLANT AND CELL PHYSIOLOGY, 57(7) (7), 1443 - 1453, English

  [Refereed]

  Scientific journal


• Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition

  Daisuke Takagi, Shigeo Takumi, Masaki Hashiguchi, Takehiro Sejima, Chikahiro Miyake

  Jul. 2016, PLANT PHYSIOLOGY, 171(3) (3), 1626 - 1634, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Suppression of Chloroplastic Alkenal/One Oxidoreductase Represses the Carbon Catabolic Pathway in Arabidopsis Leaves during Night

  Daisuke Takagi, Kentaro Ifuku, Ken-ichi Ikeda, Kanako Ikeda Inoue, Pyoyun Park, Masahiro Tamoi, Hironori Inoue, Katsuhiko Sakamoto, Ryota Saito, Chikahiro Miyake

  Apr. 2016, PLANT PHYSIOLOGY, 170(4) (4), 2024 - 2039, English

  [Refereed]

  Scientific journal


• Post-illumination transient O-2-uptake is driven by photorespiration in tobacco leaves

  Takehiro Sejima, Hitomi Hanawa, Ginga Shimakawa, Daisuke Takagi, Yuji Suzuki, Hiroshi Fukayama, Amane Makino, Chikahiro Miyake

  Feb. 2016, PHYSIOLOGIA PLANTARUM, 156(2) (2), 227 - 238, English

  [Refereed]

  Scientific journal


• Diversity in photosynthetic electron transport under [CO2]- limitation: the cyanobacterium Synechococcus sp. PCC 7002 and green alga Chlamydomonas reinhardtii drive an O2-dependent alternative electron flow and non-photochemical quenching of chlorophyll f

  G. Shimakawa, S. Akimoto, Y. Ueno, A. Wada, K. Shaku, Y. Takahashi, C. Miyake

  Some cyanobacteria, but not all, experience an induction of alternative electron flow (AEF) during CO2-limited photosynthesis. For example, Synechocystis sp. PCC 6803 (S. 6803) exhibits AEF, but Synechococcus elongatus sp. PCC 7942 does not. This difference is due to the presence of flavodiiron 2 and 4 proteins (FLV2/4) in S. 6803, which catalyze electron donation to O2. In this study, we observed a low-[CO2] induced AEF in the marine cyanobacterium Synechococcus sp. PCC 7002 that lacks FLV2/4. The AEF shows high affinity for O2, compared with AEF mediated by FLV2/4 in S. 6803, and can proceed under extreme low [O2] (about a few µM O2). Further, the transition from CO2-saturated to CO2-limited photosynthesis leads a preferential excitation of PSI to PSII and increased non-photochemical quenching of chlorophyll fluorescence. We found that the model green alga Chlamydomonas reinhardtii also has an O2-dependent AEF showing the same affinity for O2 as that in S. 7002. These data represent the diverse molecular mechanisms to drive AEF in cyanobacteria and green algae. In this paper, we further discuss the diversity, the evolution, and the physiological function of strategy to CO2-limitation in cyanobacterial and green algal photosynthesis.

  2016, Photosynth. Res., 130(1-3) (1-3), 293 - 305, English, International magazine

  [Refereed]

  Scientific journal


• Diversity in photosynthetic electron transport under [CO2]-limitation

  Ginga Shimakawa, Seiji Akimoto, Yoshifumi Ueno, Ayumi Wada, Keiichiro Shaku, Yuichiro Takahashi, Chikahiro Miyake

  2016, Photosynthesis Research, 1 - 13, English

  [Refereed]

  Scientific journal


• Altered levels of primary metabolites in response to exogenous indole-3-acetic acid in wild type and auxin signaling mutants of Arabidopsis thaliana: A capillary electrophoresis-mass spectrometry analysis

  Aya Anegawa, Miwa Ohnishi, Daisuke Takagi, Chikahiro Miyake, Chizuko Shichijo, Kimitsune Ishizaki, Hidehiro Fukaki, Tetsuro Mimura

  Mar. 2015, PLANT BIOTECHNOLOGY, 32(1) (1), 65 - 79, English

  [Refereed]

  Scientific journal


• FLAVODIIRON2 and FLAVODIIRON4 Proteins Mediate an Oxygen-Dependent Alternative Electron Flow in Synechocystis sp PCC 6803 under CO2-Limited Conditions

  Ginga Shimakawa, Keiichiro Shaku, Akiko Nishi, Ryosuke Hayashi, Hiroshi Yamamoto, Katsuhiko Sakamoto, Amane Makino, Chikahiro Miyake

  Feb. 2015, PLANT PHYSIOLOGY, 167(2) (2), 472 - U732, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Overexpression of flv3 improves photosynthesis in the cyanobacterium Synechocystis sp PCC6803 by enhancement of alternative electron flow

  Hasunuma Tomohisa, Matsuda Mami, Senga Youhei, Aikawa Shimpei, Toyoshima Masakazu, Shimakawa Ginga, Miyake Chikahiro, Kondo Akihiko

  Dec. 2014, BIOTECHNOLOGY FOR BIOFUELS, 7, 493 - 493, English

  [Refereed]

  Link to Kobe Univ. Repository (Kernel)


• Respiration accumulates Calvin cycle intermediates for the rapid start of photosynthesis in Synechocystis sp. PCC 6803

  Ginga Shimakawa, Tomohisa Hasunuma, Akihiko Kondo, Mami Matsuda, Amane Makino, Chikahiro Miyake

  Dec. 2014, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 78(12) (12), 1997 - 2007, English

  [Refereed]

  Scientific journal


• Repetitive Short-Pulse Light Mainly Inactivates Photosystem I in Sunflower Leaves

  Takehiro Sejima, Daisuke Takagi, Hiroshi Fukayama, Amane Makino, Chikahiro Miyake

  Jun. 2014, PLANT AND CELL PHYSIOLOGY, 55(6) (6), 1184 - 1193, English

  [Refereed]

  Scientific journal


• Why don't plants have diabetes? Systems for scavenging reactive carbonyls in photosynthetic organisms

  Ginga Shimakawa, Mayumi Suzuki, Eriko Yamamoto, Ryota Saito, Tatsuya Iwamoto, Akiko Nishi, Chikahiro Miyake

  Apr. 2014, BIOCHEMICAL SOCIETY TRANSACTIONS, 42, 543 - 547, English

  [Refereed]

  Scientific journal


• The Calvin Cycle Inevitably Produces Sugar-Derived Reactive Carbonyl Methylglyoxal During Photosynthesis: A Potential Cause of Plant Diabetes

  Daisuke Takagi, Hironori Inoue, Mizue Odawara, Ginga Shimakawa, Chikahiro Miyake

  Feb. 2014, PLANT AND CELL PHYSIOLOGY, 55(2) (2), 333 - 340, English

  [Refereed]

  Scientific journal


• 6 高等植物におけるalkenal/one oxidoreductase(AOR)の生理学的解析 : 植物も糖尿病を発症する(関西支部講演会,2013年度各支部会)

  齊藤 亮太, 伊福 健太郎, 池田 健一, 井上 加奈子, 三宅 親弘

  一般社団法人 日本土壌肥料学会, 2014, 日本土壌肥料学会講演要旨集, 60(0) (0), 288 - 288, Japanese

  [Refereed]


• O-2-dependent large electron flow functioned as an electron sink, replacing the steady-state electron flux in photosynthesis in the cyanobacterium Synechocystis sp PCC 6803, but not in the cyanobacterium Synechococcus sp PCC 7942

  Ryosuke Hayashi, Ginga Shimakawa, Keiichiro Shaku, Satoko Shimizu, Seiji Akimoto, Hiroshi Yamamoto, Katsumi Amako, Toshio Sugimoto, Masahiro Tamoi, Amane Makino, Chikahiro Miyake

  2014, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 78(3) (3), 384 - 393, English

  [Refereed]

  Scientific journal


• Functional Analysis of the AKR4C Subfamily of Arabidopsis thaliana: Model Structures, Substrate Specificity, Acrolein Toxicity, and Responses to Light and [CO2]

  Ryota Saito, Ginga Shimakawa, Akiko Nishi, Tatsuya Iwamoto, Katsuhiko Sakamoto, Hiroshi Yamamoto, Katsumi Amako, Amane Makino, Chikahiro Miyake

  Oct. 2013, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 77(10) (10), 2038 - 2045, English

  [Refereed]

  Scientific journal


• Acrolein, an alpha,beta-Unsaturated Carbonyl, Inhibits Both Growth and PSII Activity in the Cyanobacterium Synechocystis sp PCC 6803

  Ginga Shimakawa, Tatsuya Iwamoto, Tomohito Mabuchi, Ryota Saito, Hiroshi Yamamoto, Katsumi Amako, Toshio Sugimoto, Amane Makino, Chikahiro Miyake

  Aug. 2013, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 77(8) (8), 1655 - 1660, English

  [Refereed]

  Scientific journal


• Scavenging systems for reactive carbonyls in the cyanobacterium synechocystis sp. PCC 6803

  Ginga Shimakawa, Mayumi Suzuki, Eriko Yamamoto, Akiko Nishi, Ryota Saito, Katsuhiko Sakamoto, Hiroshi Yamamoto, Amane Makino, Chikahiro Miyake

  Japan Society for Bioscience, Biotechnology, and Agrochemistry, 2013, Bioscience, Biotechnology and Biochemistry, 77(12) (12), 2441 - 2448, English

  [Refereed]

  Scientific journal


• O2-enhanced induction of photosynthesis in rice leaves: The Mehler-ascorbate peroxidase (MAP) pathway drives cyclic electron flow within PSII and cyclic electron flow around PSI.

  Miyake C, Suzuki Y, Yamamoto H, Amako K, Makino A

  Dec. 2012, Soil Science and Plant Nutrition, 58(6) (6), 718 - 727, English

  [Refereed]

  Scientific journal


• O2 supports 3-phosphoglycerate-dependent O2 evolution in chloroplasts from spinach leaves

  Daisuke Takagi, Hiroshi Yamamoto, Katsumi Amako, Amane Makino, Toshio Sugimoto, Chikahiro Miyake

  2012, Soil Science and Plant Nutrition, 58(4) (4), 462 - 468, English

  [Refereed]

  Scientific journal


• O-2 supports 3-phosphoglycerate-dependent O-2 evolution in chloroplasts from spinach leaves

  Daisuke Takagi, Hiroshi Yamamoto, Katsumi Amako, Amane Makino, Toshio Sugimoto, Chikahiro Miyake

  2012, SOIL SCIENCE AND PLANT NUTRITION, 58(4) (4), 462 - 468, English

  [Refereed]

  Scientific journal


• Methylglyoxal functions as Hill oxidant and stimulates the photoreduction of O-2 at photosystem I: a symptom of plant diabetes

  Ryota Saito, Hiroshi Yamamoto, Amane Makino, Toshio Sugimoto, Chikahiro Miyake

  Sep. 2011, PLANT CELL AND ENVIRONMENT, 34(9) (9), 1454 - 1464, English

  [Refereed]

  Scientific journal


• Cyclic electron flow around PSI functions in the photoinhibited rice leaves

  Satoshi Kubo, Takehiro Masumura, Yuhi Saito, Hiroshi Fukayama, Yuji Suzuki, Toshio Sugimoto, Amane Makino, Katsumi Amako, Chikahiro Miyake

  Feb. 2011, SOIL SCIENCE AND PLANT NUTRITION, 57(1) (1), 105 - 113, English

  [Refereed]

  Scientific journal


• Functional Incorporation of Sorghum Small Subunit Increases the Catalytic Turnover Rate of Rubisco in Transgenic Rice.

  Ishikawa C, Htanaka , T, Misoo, S, Miyake, C, Fukayama H

  Abstract Rubisco limits photosynthetic CO2 fixation because of its low catalytic turnover rate (k  cat) and competing oxygenase reaction. Previous attempts to improve the catalytic efficiency of Rubisco by genetic engineering have gained little progress. Here we demonstrate that the introduction of the small subunit (RbcS) of high k  cat Rubisco from the C4 plant sorghum (Sorghum bicolor) significantly enhances k  cat of Rubisco in transgenic rice (Oryza sativa). Three independent transgenic lines expressed sorghum RbcS at a high level, accounting for 30%, 44%, and 79% of the total RbcS. Rubisco was likely present as a chimera of sorghum and rice RbcS, and showed 1.32- to 1.50-fold higher k  cat than in nontransgenic rice. Rubisco from transgenic lines showed a higher K  m for CO2 and slightly lower specificity for CO2 than nontransgenic controls. These results suggest that Rubisco in rice transformed with sorghum RbcS partially acquires the catalytic properties of sorghum Rubisco. Rubisco content in transgenic lines was significantly increased over wild-type levels but Rubisco activation was slightly decreased. The expression of sorghum RbcS did not affect CO2 assimilation rates under a range of CO2 partial pressures. The J  max/V  cmax ratio was significantly lower in transgenic line compared to the nontransgenic plants. These observations suggest that the capacity of electron transport is not sufficient to support the increased Rubisco capacity in transgenic rice. Although the photosynthetic rate was not enhanced, the strategy presented here opens the way to engineering Rubisco for improvement of photosynthesis and productivity in the future.

  Oxford University Press (OUP), 2011, Plant Physiol., 156(3) (3), 1603 - 1611, English

  [Refereed]

  Scientific journal


• Differences in Rubisco content and its synthesis in leaves at different positions in Eucalyptus globulus seedlings

  YUJI SUZUKI, TOMONORI KIHARA-DOI, TETSU KAWAZU, CHIKAHIRO MIYAKE, AMANE MAKINO

  Aug. 2010, Plant, Cell and Environment, 33(8) (8), 1314 - 1323, English

  [Refereed]

  Scientific journal


• Acclimation of Tobacco Leaves to High Light Intensity Drives the Plastoquinone Oxidation SystemRelationship Among the Fraction of Open PSII Centers, Non-Photochemical Quenching of Chl Fluorescence and the Maximum Quantum Yield of PSII in the Dark

  Chikahiro Miyake, Katsumi Amako, Naomasa Shiraishi, Toshio Sugimoto

  Apr. 2009, PLANT AND CELL PHYSIOLOGY, 50(4) (4), 730 - 743, English

  [Refereed]

  Scientific journal


• Metabolic pathway engineering by plastid transformation is a powerful tool for production of compounds in higher plants

  Tomohisa Hasunuma, Akihiko Kondo, Chikahiro Miyake

  Plastid transformation is a powerful tool for the production of useful compounds in higher plants through metabolic engineering, because it has many advantages over conventional nuclear transformation: high-level foreign protein accumulation, no need for a transit peptide, absence of gene silencing, and convenient transgene stacking in an operon. Plastid transformation has recently yielded remarkable results in the production of highly valued biopharmaceutical proteins and in conferring herbicide and insect resistance. Metabolic pathway engineering by plastid transformation has also produced higher levels of useful compounds than nuclear transformation. Furthermore, recent reports have shown the functional regulation of transgene expression from the plastid genome. In this review, we have focused on the progress of plastid transformation in material production from the aspect of biosynthetic pathway engineering, discussing the issues for future expansion of plastid transformation.

  Japanese Society for Plant Cell and Molecular Biology, Mar. 2009, Plant Biotechnology, 26(1) (1), 39 - 46, English

  [Refereed]

  Scientific journal


• Knockdown of the PsbP protein does not prevent assembly of the dimeric PSII supercomplexes in tobacco.

  Kunio Ido, Kentaro Ifuku, Yumiko Yamamoto, Seiko Ishihara, Akio Murakami, Keiji Takabe, Chikahiro Miyake, Fumihiko Sato

  2009, Biochemica et Biophysica Acta 1787, 873-88, English

  [Refereed]

  Scientific journal


• Biosynthesis of astaxanthin in tobacco leaves by transplastomic engineering

  Tomohisa Hasunuma, Shin-Ichi Miyazawa, Satomi Yoshimura, Yuki Shinzaki, Ken-Ichi Tomizawa, Kazutoshi Shindo, Seon-Kang Choi, Norihiko Misawa, Chikahiro Miyake

  Sep. 2008, PLANT JOURNAL, 55(5) (5), 857 - 868, English

  [Refereed]

  Scientific journal


• Overexpression of 1-deoxy-D-xylulose-5-phosphate reductoisomerase gene in chloroplast contributes to increment of isoprenoid production

  HASUNMA Tomohisa, TAKENO Shinya, HAYASHI Shunsuke, SENDAI Mayumi, BAMBA Takeshi, YOSHIMURA Satomi, TOMIZAWA Kenichi, FUKUSAKI Ei-ichiro, MIYAKE Chikahiro

  Plants synthesize a large number of isoprenoid compounds that are of industrial, nutritional and medicinal importance. 1-Deoxy-D-xylulose reductoisomerase (DXR) catalyzes the first committed step of plastidial isoprenoid-precursor biosynthesis. In the present study, we generated transplastomic tobacco plants that overproduced DXR from Synechosystis sp. strain PCC6803. The transformants showed increase in the content of various isoprenoids such as chlorophyll a, β-carotene, lutein, antheraxanthin, solanesol and β-sitosterol, indicating that the DXR reaction is one of the key steps controlling isoprenoid level in tobacco leaves. A qualitative change in isoprenoid composition was also observed. The growth phenotype of the transplastomic plants was similar to that of wild-type plants. These results showed that plastid metabolic engineering is useful in manipulating the yield of isoprenoids in plants.
  

  The Society for Biotechnology, Japan, May 2008, Journal of Bioscience and Biotechnology, Vol 105. No. 5, pp. 518-526(5) (5), 518 - 526, English

  [Refereed]

  Scientific journal


• 4-Ketoantheraxanthin, a novel carotenoid produced by the combination of the bacterial enzyme b-carotene ketolase CrtW and endogeneous carotenoid biosynthetic enzymes in hihger plants

  SHINDO Kazutoshi, HASUNMA Tomohisa, ASAGI Emiko, SANO Aya, HOTTA Eri, MINEMURA Noriko, MIYAKE Chikahiro, MAOKA Takashi, MISAWA Norihiko

  Mar. 2008, Tetrahedron Letters, Vol 49. No. 20, pp. 3294-3296, English

  [Refereed]

  Scientific journal


• Deactivation of aquaporins decreases internal conductance to CO(2) diffusion in tobacco leaves grown under long-term drought

  Shin-ichi Miyazawa, Satomi Yoshimura, Yuki Shinzaki, Masayoshi Maeshima, Chikahiro Miyake

  2008, FUNCTIONAL PLANT BIOLOGY, 35(7) (7), 553 - 564, English

  [Refereed]

  Scientific journal


• Effects of the PsbP knockdown on the photosynthetic electron transfer in Nicotiana tabacum.

  Kunio Ido, Kentaro Ifuku, Seiko Ishihara, Yumiko Yamamoto, Chikahiro Miyake, Fumihiko Sato

  2008, Photosynthesis Energy from the Sun, 5, 605 - 608, English

  International conference proceedings


• Relationship between mesophyll CO2 gas diffusion conductance and leaf plasma-membrane-type aquaporin contents in tobacco plants grown under drought conditions

  Shin-Ichi Miyazawa, Yuki Shinzaki, Tomomi Kawasaki, Masayoshi Maeshima, Chikahiro Miyake

  2007, PLANT AND CELL PHYSIOLOGY, 48, S96 - S96, English

  [Refereed]


• Ferredoxin limits cyclic electron flow around PSI (CEF-PSI) in higher plants-stimulation of CEF-PSI enhances non-photochemical quenching of Chl fluorescence in transplastomic tobacco

  Yamamoto Hiroshi, Kato Hideki, Shinzaki Yuki, Horiguchi Sayaka, Shikanai Toshiharu, Hase Toshiharu, Endo Tsuyoshi, Nishioka Minori, Makino Amane, Tomizawa Ken-ichi, Miyake Chikahiro

  2007, PLANT AND CELL PHYSIOLOGY, 48, S96

  [Refereed]


• Ferredoxin limits cyclic electron flow around PSI (CEF-PSI) in higher plants-stimulation of CEF-PSI enhances non-photochemical quenching of Chl fluorescence in transplastomic tobacco

  Hiroshi Yamamoto, Hideki Kato, Yuki Shinzaki, Sayaka Horiguchi, Toshiharu Shikanai, Toshiharu Hase, Tsuyoshi Endo, Minori Nishioka, Amane Makino, Ken-ichi Tomizawa, Chikahiro Miyake

  Oct. 2006, PLANT AND CELL PHYSIOLOGY, 47(10) (10), 1355 - 1371, English

  [Refereed]

  Scientific journal


• Effects of light intensity on cyclic electron flow around PSI and its relationship to non-photochemical quenching of Chl fluorescence in tobacco leaves

  Chikahiro Miyake, Sayaka Horiguchi, Amane Makino, Yuki Shinzaki, Hiroshi Yamamoto, Ken-Ichi Tomizawa

  Nov. 2005, Plant and Cell Physiology, 46(11) (11), 1819 - 1830, English

  [Refereed]

  Scientific journal


• Purification and cDNA Cloning of Chloroplastic Monodehydroascorbate Reductase from Spinach

  SANO Satoshi, TAO Satoru, ENDO Yuko, INABA Tomomi, HOSSAIN M. Anwar, MIYAKE Chikahiro, MATSUO Michinori, AOKI Hideyuki, ASADA Kozi, SAITO Kazumi

  The chloroplastic isoform of monodehydroascorbate (MDA) radical reductase was purified from spinach chloroplasts and leaves. The cDNA of chloroplastic MDA reductase was cloned, and its deduced amino acid sequence, consisting of 497 residues, showed high homology with those of putative organellar MDA reductases deduced from cDNAs of several plants. The amino acid sequence of the amino terminal of the purified enzyme suggested that the chloroplastic enzyme has a transit peptide consisting of 53 residues. A southern blot analysis suggested the occurrence of a gene encoding another isoform homologous to the chloroplastic isoform in spinach. The recombinant enzyme was highly expressed in Eschericia coli using the cDNA, and purified to a homogeneous state with high specific activity. The enzyme properties of the chloroplastic isoform are presented in comparison with those of the cytosolic form.

  Japan Society for Bioscience, Biotechnology, and Agrochemistry, Apr. 2005, Agricultural and Biological Chemistry, 69(4) (4), 762 - 772, English


• Cyclic electron flow around photosystem I is essential for photosynthesis.

  Yuri Munekage, Mihoko Hashimoto, Chikahiro Miyake, Ken-ichi Tomizawa, Tsuyoshi Endo, Masao Tasaka, Toshiharu Shikanai

  Photosynthesis provides at least two routes through which light energy can be used to generate a proton gradient across the thylakoid membrane of chloroplasts, which is subsequently used to synthesize ATP. In the first route, electrons released from water in photosystem II (PSII) are eventually transferred to NADP+ by way of photosystem I (PSI). This linear electron flow is driven by two photochemical reactions that function in series. The cytochrome b6f complex mediates electron transport between the two photosystems and generates the proton gradient (DeltapH). In the second route, driven solely by PSI, electrons can be recycled from either reduced ferredoxin or NADPH to plastoquinone, and subsequently to the cytochrome b6f complex. Such cyclic flow generates DeltapH and thus ATP without the accumulation of reduced species. Whereas linear flow from water to NADP+ is commonly used to explain the function of the light-dependent reactions of photosynthesis, the role of cyclic flow is less clear. In higher plants cyclic flow consists of two partially redundant pathways. Here we have constructed mutants in Arabidopsis thaliana in which both PSI cyclic pathways are impaired, and present evidence that cyclic flow is essential for efficient photosynthesis.

  Jun. 2004, Nature, 429(6991) (6991), 579 - 82, English, International magazine

  Scientific journal


• The evolution of the water-water cycle and oxygen utilization as the starter of photosynthesis

  C. Miyake, A. Makino

  Japan Society for Bioscience, Biotechnology, and Agrochemistry, Jul. 2003, Chemistry and Biology, 41(7) (7), 478 - 487, Japanese

  [Refereed]

  Scientific journal


• Mechanism of the reaction catalyzed by dehydroascorbate reductase from spinach chloroplasts

  T Shimaoka, C Miyake, A Yokota

  Mar. 2003, EUROPEAN JOURNAL OF BIOCHEMISTRY, 270(5) (5), 921 - 928, English

  [Refereed]

  Scientific journal


• Physiological functions of the water-water cycle and the cyclic electron flow around PSI in rice including RbcS antisense plants

  A Makino, C Miyake, A Yokota, A Ushio, T Mae

  2003, PLANT AND CELL PHYSIOLOGY, 44, S14 - S14, English

  [Refereed]


• Stable form of ascorbate peroxidase from the red alga Galdieria partita similar to both chloroplastic and cytosolic isoforms of higher plants

  S Kitajima, M Ueda, S Sano, C Miyake, T Kohchi, K Tomizawa, S Shigeoka, A Yokota

  Nov. 2002, BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 66(11) (11), 2367 - 2375, English

  [Refereed]

  Scientific journal


• Physiological functions of the water-water cycle (Mehler reaction) and the cyclic electron flow around PSI in rice leaves

  Amane Makino, Chikahiro Miyake, Akiho Yokota

  Japanese Society of Plant Physiologists, Sep. 2002, Plant and Cell Physiology, 43(9) (9), 1017 - 1026, English

  [Refereed]

  Scientific journal


• Citrulline and DRIP-1 protein (ArgE homologue) in drought tolerance of wild watermelon

  A Yokota, S Kawasaki, M Iwano, C Nakamura, C Miyake, K Akashi

  Jun. 2002, ANNALS OF BOTANY, 89, 825 - 832, English

  [Refereed]

  Scientific journal


• オルタナティブ光合成電子伝達反応 : 見えてきた! 分子的実体とその生理的役割

  三宅 親弘

  Japan Society for Bioscience, Biotechnology, and Agrochemistry, Feb. 2002, 化学と生物, 40(2) (2), 115 - 122, Japanese


• Citrulline, a novel compatible solute in drought-tolerant wild watermelon leaves, is an efficient hydroxyl radical scavenger

  K Akashi, C Miyake, A Yokota

  Nov. 2001, FEBS LETTERS, 508(3) (3), 438 - 442, English

  [Refereed]

  Scientific journal


• Characterization of ascorbate peroxidases from unicellular red alga Galdieria partita

  S Sano, M Ueda, S Kitajima, T Takeda, S Shigeoka, N Kurano, S Miyachi, C Miyake, A Yokota

  Apr. 2001, PLANT AND CELL PHYSIOLOGY, 42(4) (4), 433 - 440, English

  [Refereed]

  Scientific journal


• Chloroplast development in Arabidopsis thaliana requires the nuclear-encoded transcription factor Sigma B

  Y Shirano, H Shimada, K Kanamaru, M Fujiwara, K Tanaka, H Takahashi, K Unno, S Sato, S Tabata, H Hayashi, C Miyake, A Yokota, D Shibata

  Nov. 2000, FEBS LETTERS, 485(2-3) (2-3), 178 - 182, English

  [Refereed]

  Scientific journal


• Responses of wild watermelon to drought stress: Accumulation of an ArgE homologue and citrulline in leaves during water deficits

  S Kawasaki, C Miyake, T Kohchi, S Fujii, M Uchida, A Yokota

  Jul. 2000, PLANT AND CELL PHYSIOLOGY, 41(7) (7), 864 - 873, English

  [Refereed]

  Scientific journal


• Aromatic monoamine-induced immediate oxidative burst leading to an increase in cytosolic Ca2+ concentration in tobacco suspension culture

  Tomonori Kawano, Reinhard Pinontoan, Nobuyuki Uozumi, Chikahiro Miyake, Kozi Asada, Pappachan E. Kolattukudy, Shoshi Muto

  Japanese Society of Plant Physiologists, 2000, Plant and Cell Physiology, 41(11) (11), 1251 - 1258, English

  [Refereed]

  Scientific journal

• Oxidative stress in crop production: Damage, tolerance, and avoidance by its prediction

  Suzuki Yuji, Kobayashi Masaru, Kobayashi Yuriko, Ohkama-Ohtsu Naoko, Ifuku Kentaro, Miyake Chikahiro

  環境ストレスは作物の生産性を低下させるが，その原因の一つに活性酸素種(ROS)による酸化ストレスがある。作物の生産性低下を防ぐうえで，酸化ストレスによる植物への障害，これに対する耐性機構，さらには酸化ストレスの予知と回避についての可能性，といった点は重要な情報となる。ホウ素欠乏による酸化ストレスの発生機構。ゲノム・トランスクリプトーム解析から見えた根の酸化ストレス応答とその多様性。含硫代謝産物を介した植物の酸化還元制御。光化学系IIからの活性酸素発生を抑制する防御機構の重要性。光呼吸による過剰光エネルギーに対する防御。内在的活性酸素生成を目的としたパルス法の確立と栽培環境診断への応用～P700酸化システムにもとづく活性酸素(ROS)診断の実用化～。

  Japanese Society of Soil Science and Plant Nutrition, 2019, Japanese Journal of Soil Science and Plant Nutrition, 90(4) (4), 273 - 278, Japanese


• イネにおけるP700吸光パラメーターによる水ストレス診断

  和田慎也, 和田慎也, 鈴木雄二, 鈴木雄二, 高木大輔, 高木大輔, 三宅親弘, 三宅親弘, 牧野周, 牧野周

  29 Aug. 2018, 日本土壌肥料学会講演要旨集, 64, 56, Japanese


• Medium-chain dehydrogenase/reductase and aldo-keto reductase scavenge reactive carbonyls in Synechocystis sp. PCC 6803

  Ginga Shimakawa, Ayaka Kohara, Chikahiro Miyake

  Wiley Blackwell, 01 Mar. 2018, FEBS Letters, 592(6) (6), 1010 - 1019, English

  Report scientific journal


• 光化学系IIシトクロムb559におけるアンチマイシンAの影響

  高木大輔, 伊福健太郎, 西村太志, 三宅親弘

  Mar. 2018, 第59回 日本植物生理学会年会, Japanese

  Summary national conference


• 植物が安心して光合成できるワケ : PSⅠを光傷害から護るP700酸化システム—P700 oxidation system protects PSⅠ against photo-oxidative damage : Why are plants safe in the light?

  嶋川 銀河, 三宅 親弘

  東京 : 日本光合成研究会, Apr. 2017, 光合成研究 = News letter / The Japanese Society of Photosynthesis Research, 27(1) (1), 4 - 15, Japanese


• Editorial: How do photosynthetic organisms manage light stress? A tribute to the late professor Kozi Asada

  Jun'Ichi Mano, Tsuyoshi Endo, Chikahiro Miyake

  2016, Plant and Cell Physiology, 57(7) (7), 1351 - 1353

  Book review


• NADPH-dependent alkenal/one oxidoreductase (AOR) supports the growth and protect from oxidative stress in Arabidopsis thaliana

  Takagi Daisuke, Kentaro Ifuku, Hironori Inoue, Masahiro Tamoi, Ken-ichi Ikeda, Kanako Ikeda Inoue, Hiroshi Fukayama, Chikahiro Miyake

  Mar. 2015, 第56回日本植物生理学会年会, Japanese

  Summary national conference


• これまで欠けていた、速度論的評価に基づく、 オルタナティブ・エレクトロン・フロー活性の比較と光合成におけるO2の役割 ～生理的な意味が見える、本丸へ挑む～

  TAKAGI DAISUKE, MIYAKE CHIKAHIRO

  日本光合成研究会, 2014, 光合成研究, 24(3) (3), 97 - 110, Japanese

  [Refereed]

  Introduction scientific journal


• 7 RbcL欠損タバコ葉緑体への優良Rubisco-rbcLの導入(東北支部講演会,2012年度各支部会)

  鈴木 直紀, 関谷 卓生, 表谷 拓郎, 鈴木 雄二, 山本 宏, 三宅 親弘, 牧野 周

  一般社団法人日本土壌肥料学会, 11 Sep. 2013, 日本土壌肥料学会講演要旨集, (59) (59), 253 - 253, Japanese


• 4-1-13 春コムギ、冬コムギ2品種間における光合成能力の比較(4-1 植物の多量栄養素)

  高木 大輔, 宅見 薫雄, 三宅 親弘

  一般社団法人日本土壌肥料学会, 11 Sep. 2013, 日本土壌肥料学会講演要旨集, (59) (59), 58 - 58, Japanese


• 4-1-14 シロイヌナズナにおけるAKR4C familyの機能解析(4-1 植物の多量栄養素)

  齊藤 亮太, 嶋川 銀河, 西 晶子, 坂本 克彦, 山本 宏, 尼子 克己, 杉本 敏男, 牧野 周, 三宅 親弘

  一般社団法人日本土壌肥料学会, 11 Sep. 2013, 日本土壌肥料学会講演要旨集, (59) (59), 58 - 58, Japanese


• 4-1-12 光合成誘導におけるO_2に依存した電子伝達反応の解析(4-1 植物の多量栄養素)

  瀬島 健裕, 鈴木 雄二, 高木 大輔, 山本 宏, 杉本 敏男, 尼子 克己, 牧野 周, 三宅 親弘

  一般社団法人日本土壌肥料学会, 11 Sep. 2013, 日本土壌肥料学会講演要旨集, (59) (59), 57 - 57, Japanese


• 4-1-19 RbcL欠損タバコ葉緑体への優良Rubisco-rbcLの導入(4-1 植物の多量栄養素)

  関谷 卓生, 鈴木 直紀, 表谷 拓郎, 鈴木 雄二, 山本 宏, 三宅 親弘, 牧野 周

  一般社団法人日本土壌肥料学会, 11 Sep. 2013, 日本土壌肥料学会講演要旨集, (59) (59), 60 - 60, Japanese


• イネ生葉におけるMAP-pathwayによる光合成誘導メカニズムの解析

  瀬島健裕, 鈴木雄二, 高木大輔, 山本宏, 杉本敏男, 尼子克己, 牧野周, 三宅親弘

  Mar. 2013, 第54回日本植物生理学会, Japanese


• 9-1 イネ生葉におけるO_2に依存した光合成誘導メカニズムの解析(9.植物の多量栄養素,2012年度鳥取大会)

  瀬島 健裕, 鈴木 雄二, 高木 大輔, 山本 宏, 杉本 敏男, 尼子 克己, 牧野 周, 三宅 親弘

  一般社団法人日本土壌肥料学会, 04 Sep. 2012, 日本土壌肥料学会講演要旨集, (58) (58), 53 - 53, Japanese


• P19-23 丹波黒(Glycine max)種子成分に及ぼす施肥方法の影響(19.肥料および施肥法,2012年度鳥取大会)

  入川 草太, 鈴木 武志, 三宅 親弘, 杉本 敏男

  一般社団法人日本土壌肥料学会, 04 Sep. 2012, 日本土壌肥料学会講演要旨集, (58) (58), 142 - 142, Japanese


• タバコrbcL遺伝子のポプラrbcL遺伝子への置換によるhybrid Rubiscoの形成

  鈴木 直紀, 関谷 卓生, 表谷 拓郎, 鈴木 雄二, 山本 宏, 三宅 親弘, 牧野 周

  Mar. 2012, 第53回日本植物生理学会, Japanese


• Cyanobacterium Synechocystis sp. PCC6803 におけるO2存性オルタナティブ・エレクトロン・フロー (AEF)の生理的役割

  林 良祐, 清水 聡子, 山本 宏, 藍川 晋平, 蓮沼 誠久, 秋本 誠志, 近藤 昭彦, 三宅 親弘

  Mar. 2012, 第53回日本植物生理学会, Japanese


• 植物葉緑体メチルグリオキサール代謝メカニズムの解明 メチルグリオキサールは内在的酸素光還元メディエーターである

  斉藤 亮太, 山本 宏, 牧野 周, 杉本 敏男, 三宅 親弘

  Sep. 2011, 第75回日本植物学会, Japanese


• 12 シロイヌナズナを用いたThe Water-Water Cycle機能低下異変体のスクリーニングと候補株の性質 : 光合成の酸素制御因子の同定(関西支部講演会,2010年度各支部会講演要旨)

  高木 大輔, 杉本 敏男, 三宅 親弘

  一般社団法人日本土壌肥料学会, 08 Aug. 2011, 日本土壌肥料学会講演要旨集, (57) (57), 329 - 329, Japanese


• 11 シアノバクテリアでのオルタナティブ・エレクトロン・フロー(AEF)評価系の確立(関西支部講演会,2010年度各支部会講演要旨)

  進藤 沙織, 林 吉祐, 真野 陽人, 杉本 敏男, 近藤 昭彦, 藍川 晋平, 蓮沼 誠久, 秋本 誠志, 三宅 親弘

  一般社団法人日本土壌肥料学会, 08 Aug. 2011, 日本土壌肥料学会講演要旨集, (57) (57), 329 - 329, Japanese


• 10 葉緑体におけるMethylglyoxal解毒機構の解明1 : 植物はなぜ糖尿病にならないのか(関西支部講演会,2010年度各支部会講演要旨)

  岩本 達弥, 斉藤 亮太, 久保 智史, 杉本 敏男, 伊福 健太郎, 佐藤 文彦, 牧野 周, 三宅 親弘

  一般社団法人日本土壌肥料学会, Aug. 2011, 日本土壌肥料学会講演要旨集, (57) (57), 329 - 329, Japanese

  Summary national conference


• 高等植物葉緑体での3-ホスホグリセリン酸に依存した光合成における酸素の重要性 ATP/NADPH=1 でさえリニアエレクトロンフローでは満たせられない

  高木 大輔, 山本 宏, 尼子 克己, 三宅 親弘

  2011, 第75回日本植物学会, Japanese


• Alternative Electron Flows (Water-Water Cycle and Cyclic Electron Flow Around PSI) in Photosynthesis : Molecular Mechanisms and Physiological Functions

  MIYAKE Chikahiro

  Oxford University Press, 01 Dec. 2010, Plant and Cell Physiology, 51(12) (12), 1951 - 1963, English


• P9-6 葉位の異なるEucalyptus globulus葉におけるRubiscoの遺伝子発現(ポスター紹介,9.植物の多量栄養素,2010年度北海道大会)

  鈴木 雄二, 土居(木原) 智仁, 河津 哲, 三宅 親弘, 牧野 周

  一般社団法人日本土壌肥料学会, 07 Sep. 2010, 日本土壌肥料学会講演要旨集, (56) (56), 64 - 64, Japanese


• Metabolic turnover analysis by a combination of in vivo C-13-labelling from (CO2)-C-13 and metabolic profiling with CE-MS/MS reveals rate-limiting steps of the C-3 photosynthetic pathway in Nicotiana tabacum leaves

  Tomohisa Hasunuma, Kazuo Harada, Shin-Ichi Miyazawa, Akihiko Kondo, Eiichiro Fukusaki, Chikahiro Miyake

  Mar. 2010, JOURNAL OF EXPERIMENTAL BOTANY, 61(4) (4), 1041 - 1051, English


• シロイヌナズナでのAEF(the Water-Water Cycle and Cyclic Electron Flow around PSI)の強光順化への応答：O2-dependent electron flowはelectron sinkとして機能し、PQ酸化およびNPQ誘導に貢献する

  桑原亮, 尼子克己, 山本 宏, 鹿内利治, 杉本敏男, 鈴木雄二, 牧野 周, 三宅親弘

  2010, 日本農芸化学会2010年度関西支部大会, Japanese


• 9-22 イネでの、葉緑体光合成電子伝達系の窒素(N)栄養応答(9.植物の多量栄養素,2009年度京都大会)

  真野 陽人, 渡辺 竜馬, 桑原 亮, 増村 威宏, 斉藤 雄飛, 尼子 克己, 深山 浩, 杉本 敏男, 三宅 親弘

  一般社団法人日本土壌肥料学会, 15 Sep. 2009, 日本土壌肥料学会講演要旨集, (55) (55), 72 - 72, Japanese


• Understanding the alternative electron flow in photosynthesis: the water-water cycle and cyclic electron flow around PSI through qL model unifying the parameters of Chl fluorescence

  久保 智史, 杉本 敏男, 三宅 親弘

  日本光合成学会, Aug. 2009, News letter, 19(2) (2), 66 - 74, Japanese


• 10-11 高等植物におけるRubiscoの性能と光合成速度の変異について(10.植物の代謝,2008年度愛知大会)

  表谷 拓郎, 鈴木 雄二, 河津 哲, 山本 宏, 三宅 親弘, 牧野 周

  一般社団法人日本土壌肥料学会, 09 Sep. 2008, 日本土壌肥料学会講演要旨集, (54) (54), 99 - 99, Japanese


• Ribulose 1,5-bisphosphate carboxylase/oxygenase large subunit translation is regulated in a small subunit-independent manner in the expanded leaves of tobacco

  Katsuhiko Ichikawa, Chikahiro Miyake, Megumi Iwano, Masami Sekine, Atsuhiko Shinmyo, Ko Kato

  Feb. 2008, PLANT AND CELL PHYSIOLOGY, 49(2) (2), 214 - 225, English


• Dynamic metabolic profiling using in vivo stable isotope labeling

  Hasunuma Tomohisa, Harada Kazuo, Miyake Chikahiro, Fukusaki Eiichiro

  3章 単離・精製・活性測定 1. 代謝産物量の定量 b

  Institute of Low Temperature Science, Hokkaido University, 2008, Low temperature science, 67, 169 - 174, Japanese


• Characterization of Photosynthetic Properties of Salt and High-light Tolerant Eucalyptus camaldulensis:-Heat Dissipation Process and Its Induction Mechanism-

  Miyake Chikahiro, Miyazawa Shinichi, Iwamae Tomoko

  THE JAPANESE FORESTRY SOCIETY, 2008, The Japanese Forest Society Congress, 119(0) (0), 276 - 276, Japanese


• Effects of the PsbP knockdown on the photosynthetic electron transfer in Nicotiana tabacum.

  K. Ido, K. Ifuku, S. Ishihara, Y. Yamamoto, C. Miyake, F. Sato

  Feb. 2007, PHOTOSYNTHESIS RESEARCH, 91(2-3) (2-3), 192 - 192, English

  Summary international conference


• Photoinactivation of Ascorbate Peroxidase in Isolated Tobacco Chloroplasts : Galdieria partita APX Maintains the Electron Flux through the Water-Water Cycle in Transplastomic Tobacco Plants

  MIYAKE Chikahiro, SHINZAKI Yuki, NISHIOKA Minori, HORIGUCHI Sayaka, TOMIZAWA Ken-Ichi

  Japanese Society of Plant Physiologists, 01 Feb. 2006, Plant and Cell Physiology, 47(2) (2), 200 - 210, English


• CO_2 Response of Cyclic Electron Flow around PSI (CEF-PSI) in Tobacco Leaves-Relative Electron fluxes through PSI and PSII Determine the Magnitude of Non-photochemical Quenching (NPQ) of Chl Fluorescence

  MIYAKE Chikahiro, MIYATA Momoko, SHINZAKI Yuki, TOMIZAWA Ken-ichi

  Japanese Society of Plant Physiologists, 01 Apr. 2005, Plant and Cell Physiology, 46(4) (4), 629 - 637, English


• A limiting step of photosynthesis during induction phase in rice

  Sasaki Eriko, Hirotsu Naoki, Makino Amane, Mae Tadahiko, Miyake Chikahiro

  2005, Plant and Cell Physiology Supplement, 2005(0) (0), 635 - 635, English

  Summary international conference


• Enhancement of Cyclic Electron Flow Around PSI at High Light and its Contribution to the Induction of Non-Photochemical Quenching of Chl Fluorescence in Intact Leaves of Tobacco Plants

  MIYAKE Chikahiro, SHINZAKI Yuki, MIYATA Momoko, TOMIZAWA Ken-ichi

  Japanese Society of Plant Physiologists, 01 Oct. 2004, Plant and Cell Physiology, 45(10) (10), 1426 - 1433, English


• Physiological function of the water-water cycle during the photosynthetic induction

  E Sasaki, A Makino, T Mae, C Miyake

  2004, PLANT AND CELL PHYSIOLOGY, 45, S43 - S43, English

  Summary international conference


• 10-7 イネにおけるwater-water cycleとPS I cyclic電子伝達の生理的機能(10.植物の代謝)

  牧野 周, 前 忠彦, 三宅 親弘

  一般社団法人日本土壌肥料学会, 20 Aug. 2003, 日本土壌肥料学会講演要旨集, (49) (49), 92 - 92, Japanese


• Cyclic Electron Flow within PSII Protects PSII from its Photoinhibition in Thylakoid Membranes from Spinach Chloroplasts

  MIYAKE Chikahiro, OKAMURA Mitsutaka

  Japanese Society of Plant Physiologists, 01 Apr. 2003, Plant and Cell Physiology, 44(4) (4), 457 - 462, English


• Purification and Characterization of Class-I and Class-II Fructose-1,6-bisphosphate Aldolases from the Cyanobacterium Synechocytis sp. PCC6803

  NAKAHARA Ken, YAMAMOTO Hiroshi, MIYAKE Chikahiro, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 01 Mar. 2003, Plant and Cell Physiology, 44(3) (3), 326 - 333, English


• Cyclic Electron Flow within PSII Functions in Intact Chloroplasts from Spinach Leaves

  MIYAKE Chikahiro, YONEKURA Kuniaki, KOBAYASHI Yoshichika, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 01 Aug. 2002, Plant and Cell Physiology, 43(8) (8), 951 - 957, English


• Functional analysis of DRIP-1, a drought-induced polypeptide in wild watermelon

  K Akashi, K Takahara, R Yamada, C Miyake, A Yokota

  2002, PLANT AND CELL PHYSIOLOGY, 43, S112 - S112, English

  Summary international conference


• Cyclic Flow of Electrons within PSII in Thylakoid Membranes

  MIYAKE Chikahiro, YOKOTA Akiho

  Japanese Society of Plant Physiologists, May 2001, Plant and Cell Physiology, 42(5) (5), 508 - 515, English


• ANALYSIS OF DROUGHT-INDUCED METALLOTHIONEIN GENE IN WILD-TYPE WATERMELON (Citrullus lanatus) :

  NISHIMURA Noriyuki, AKASHI Kinya, MIYAKE Chikahiro, KOHCHIi Takayuki, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 2001, Plant and cell physiology, 42, s134, English


• Hydroxyl Radical Scavenging Activity of Citrulline : Implication for Drought-tolerance of Wild Watermelon :

  AKASHI Kinya, MIYAKE Chikahiro, KOHCHI Takayuki, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 2001, Plant and cell physiology, 42, s134, English


• Alternative electron flow in the leaves of C4 plant, Maize :

  Iida Nao, Yokota Akiho, Miyake Chikahiro

  Japanese Society of Plant Physiologists, 2001, Plant and cell physiology, 42, s157, English


• Physiological functions of the water-water cycle as electron sink and O_2-independent alternative electron flow in PSII :

  MIYAKE Chikahiro, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 2001, Plant and cell physiology, 42, s6, English


• Phenylethylamine-Induced Generation of Reactive Oxygen Species and Ascorbate Free Radicals in Tobacco Suspension Culture: Mechanism for Oxidative Burst Mediating Ca^<2+> Influx

  KAWANO Tomonori, PINONTOAN Reinhard, UOZUMI Nobuyuki, MORIMITSU Yasujiro, MIYAKE Chikahiro, ASADA Kozi, MUTO Shoshi

  Japanese Society of Plant Physiologists, Nov. 2000, Plant and Cell Physiology, 41(11) (11), 1259 - 1266, English


• Purification and Characterization of Chloroplast Dehydroascorbate Reductase from Spinach Leaves

  SHIMAOKA Taise, YOKOTA Akiho, MIYAKE Chikahiro

  Japanese Society of Plant Physiologists, Oct. 2000, Plant and Cell Physiology, 41(10) (10), 1110 - 1118, Japanese


• Formate protects photosynthetic machinery from photoinhibition

  T Shiraishi, EI Fukusaki, C Miyake, A Yokota, A Kobayashi

  Jun. 2000, JOURNAL OF BIOSCIENCE AND BIOENGINEERING, 89(6) (6), 564 - 568, English


• STRUCTURE/FUNCTION RELATIONSHIPS ESPECIALLY ABOUT FALLOVER PHENOMENON OF RUBISCO FROM Chlamydomonas reinhardtii :

  MIZOHATA Eiichi, TOMIZAWA Kenichi, MIYAKE Chikahiro, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 2000, Plant and cell physiology, 41, s113, English


• Determination of the Rate of Photoreduction of O_2 in the Water-Water Cycle in Watermelon Leaves and Enhancement of the Rate by Limitation of Photosynthesis :

  Miyake Chikahiro, Yokota Akiho

  A study was performed to determine how the electron fluxes for the photosynthetic carbon reduction(PCR) and the photorespiratory carbon oxidation(PCO) cycles affect the photoreduction of O_2 at PSI, which is the limiting step in the water-water cycle. Simultaneous measurements were made of CO_2-gas exchange, transpiration and quantum yield of PSII [Φ(PSII)] using leaves of watermelon(Citrullus lanatus). The total electron flux in PSII [Je(PSII)], as estimated from Φ(PSII), was always larger than the total electron flux required for the PCR and PCO cycles at various partial pressures of CO_2 and O_2 and 1, 100 μmol photons m^<-2>s^<-1>. This observation suggested the existence of an alternative electron flux(Ja). Ja was divided into O_2-dependent [Ja(O_2-depend)] and O_2-independent [Ja(O_2-independ)] components. The magnitude of half Ja(O_2-depend), 7.5 to 9.5 μmol e^-m^<-2>s<-1> and its apparent K_m for O_2, about 8.0 kPa, could be accounted for by the photoreduction of O_2 at PSI either mediated by ferredoxin or catalyzed by monodehydroascorbate reductase. The results indicated that Ja(O_2-depend)was driven by the water-water cycle. A decrease in the intercellular partial pressure of CO_2 from 23 to 5.0 Pa at 21 kPa O_2 enhanced Ja(O_2-depend)by a factor of 1.3. Saturation of the activities of both the PCR and PCO cycles by increasing the photon flux density induced Ja. These results indicate the electron flux in PSII that exceeds the flux required for the PCR and PCO cycles induces the photoreduction of O_2 in the water-water cycle.

  Japanese Society of Plant Physiologists, 2000, Plant and cell physiology, 41(3) (3), 335 - 343, English


• Drought responses of the quantum yield of PSII and the activities of active oxygen-scavenging enzymes both in wild and cultivar watermelons :

  MIYAKE Chikahiro, YOKOTA Akiho

  Japanese Society of Plant Physiologists, 2000, Plant and cell physiology, 41, s146, English


• Thioredoxin peroxidase in the Cyanobacterium Synechocystis sp. PCC 6803

  H Yamamoto, C Miyake, KJ Dietz, KI Tomizawa, N Murata, A Yokota

  Mar. 1999, FEBS LETTERS, 447(2-3) (2-3), 269 - 273, English


• Physiological Fucntions of Photorespiration and Water-Water Cycle in Wild Watermelon Leaves under High Light and Low Partial Pressure of CO_2 conditions and in vivo diagnosis of oxidative stress in chloroplasts

  MIYAKE Chikahiro, YOKOTA Akiho

  Mar. 1999, Plant and cell physiology, 40, s119 - s119, English


• Molecular analysis of drought-tolerant with watermelon from the Botawana desert

  KAWASAKI Shinji, MIYAKE Chikahiro, NAKAMURA Chie, FUJII Shinichiro, YOKOTA Akiho

  Mar. 1999, Plant and cell physiology, 40, s91 - s91, English


• ANALYSIS OF THE RUBISCO OXYGENASE REACTION

  OKADA Sachiko, MIYAKE Chikahiro, YOKOTA Akiho

  Mar. 1999, Plant and cell physiology, 40, s116 - s116, English


• Effects of C1 compounds on plant metabolisms (part4) : protecting effects against photoinhibition.

  SHIRAISHI Takehiko, FUKUSAKI Ei-ichiro, MIYAKE Chikahiro, YOKOTA Akiho, KAJIYAMA Shin-ichiro, OKAZAWA Atsushi, KOBAYASHI Akio

  The Janapese Society for Chemical Regulation of Plants, 1999, Chemical Regulation of Plants, 34(2) (2), 351 - 352, Japanese


• 61 Effects of C1 compounds on plant metabolisms (part4)(protecting effects against photoinhibition)

  Shiraishi Takehiko, Fukusaki Ei-ichiro, Miyake Chikahiro, Yokota Akiho, Kajiyama Shin-ichiro, Okazawa Atsushi, Kobayashi Akio

  In plants, environmental adversity often leads to the formation of highly reactive oxy gen species. Even though light is the source of energy for photosynthesis, it can also be harmful to plants. Light-induced damage is targeted mainly to photosystem II and leads to the inactivation of electron transport systems and subsequent oxidative destruction of the reaction centers, in particular to the deactivation of PS II center proteins. We showed that incubation of rice leaf under the high light with CO_2-depleted air causes serious demage on photosynthesis, however the application of potassium formate or methanol could protect rice photosynthesis form photoinhibition.

  The Janapese Society for Chemical Regulation of Plants, 1999, The Janapese Society for Chemical Regulation of Plants, Abstract, 34(0) (0), 121 - 122, Japanese


• THIOREDOXIN PEROXIDASE IN CYANOBACTERIA, Synechocystis sp. PCC6803 AND Synechococcus sp. PCC7942.

  YAMAMOTO Hiroshi, MIYAKE Chikahiro, DIETZ Karl-Josef, TOMIZAWA Ken-ichi, YOKOTA Akiho, MURATA Norio

  May 1998, Plant and cell physiology, 39, S18 - S18, English


• Purification and molecular properties of ascorbate peroxidase from bovine eye

  Naoki Wada, Shigeru Kinoshita, Michinori Matsuo, Katsumi Amako, Chikahiro Miyake, Kozi Asada

  Academic Press Inc., 14 Jan. 1998, Biochemical and Biophysical Research Communications, 242(2) (2), 256 - 261, English


• The FAD-Enzyme Monodehydroascorbate Radical Reductase Mediates Photoproduction of Superoxide Radicals in Spinach Thylakoid Membranes :

  Miyake Chikahiro, Schreiber Ulrich, Hormann Henning, Sano Satoshi, Asada Kozi

  The photoreduction of dioxygen in spinach thylakoid membranes was enhanced about 10-fold by the FAD-enzyme monodehydroascorbate radical (MDA) reductase at 1 μM. The primary photoreduced product of dioxygen catalyzed by MDA reductase was the superoxide radical, as evidenced by the inhibition of photoreduction of Cyt c by superoxide dismutase. The apparent K_m for dioxygen of the MDA reductase-dependent photoreduction of dioxygen was 100 μM, higher by one order of magnitude than that observed with thylakoid membranes only. Glutathione reductase, ferredoxin-NADP^+ reductase, and glycolate oxidase also mediated the photoproduction of superoxide radicals in thylakoid membranes at rates similar to those with MDA reductase. Among these flavoenzymes, MDA reductase is the most likely mediator stimulating the photoreduction of dioxygen in chloroplasts;its function in the protection from photoinhibition under excess light is discussed.

  Japanese Society of Plant Physiologists, 1998, Plant and cell physiology, 39(8) (8), 821 - 829, English


• RESISTANCE TO ENVIRONMENTAL STRESS IN TRANSGENIC TOBACCO OVEREXPRESSING OF CATALASE FROM E. coli IN CHLOROPLASTS

  TAKEDA Toru, YOSHIMURA Yukiko, TAMOI Masahiro, SHIKANAI Toshiharu, MIYAKE Chikahiro, SANO Satoshi, TOMIZAWA Ken-ichi, YOKOTA Akiho, SHIGEOKA Shigeru

  Mar. 1997, Plant and cell physiology, 38, s68, English


• ΔpH across thylakoid membranes regulates Fallover of ribulose-1, 5-bisphosphate (RuBP) carboxylase/oxygenase (RuBiSCO) in radish leaves

  MIYAKE Chikahiro, YOKOTA Akiho

  Mar. 1997, Plant and cell physiology, 38, s33, English


• Environmental stress resistance of the genetic transformed tobacco introduced a of Escherichia coli catalase genes.

  武田徹, 義村由紀子, 田茂井政宏, 鹿内利治, 三宅親弘, 佐野智, 富沢健一, 横田明穂, 重岡成

  1997, 日本植物生理学会年会要旨集, 37th(1997)


• DETECTION OF PHOTOOXIDATIVE STRESS BY MONODEHYDROASCORBATE IN LEAVES

  OHNO Chiaki, MANO Junichi, MIYAKE Chikahiro, HEBER Ulrich, ASADA Kozi

  Mar. 1996, Plant and cell physiology, 37, 32 - 32, English


• Monodehydroascorbate radical reductase-dependent photoreduction of oxygen in chloroplast thylakoids

  MIYAKE Chikahiro, SCHREIBER Ulrich, HORMANN Henning, SANO Satoshi, ASADA Kozi

  Mar. 1996, Plant and cell physiology, 37, 79 - 79, English


• Monodehydroascorbate Radical Detected by Electron Paramagnetic Resonance Spectrometry Is a Sensitive Probe of Oxidative Stress in Intact Leaves :

  Heber Ulrich, Miyake Chikahiro, Mano Junichi, Ohno Chiaki, Asada Kozi

  Monodehydroascorbate radical (MDA) was deter-mined in leaf segments of several plant species using electron paramagnetic resonance spectrometry. When the leaves were young and healthy, MDA was often below de-tection level in both the light and dark. However, in senescent leaves, higher levels of MDA were observed in the light than in the dark. After removal of ascorbate by infiltration of such leaves with ascorbate oxidase, dark-signals of MDA did not disappear; thus the apoplast was not a major source of MDA in the dark. Methylviologen induced high levels of light-dependent MDA, indicating the participation of the photoproduced superoxide and the hydrogen peroxide derived from the superoxide in the production of MDA in chloroplasts. The photoproduction of MDA was greatly enhanced by intense light, water stress, and suppression of the photosynthetic reactions due to either infiltration or cyanide. Thus, MDA is a sensitive endogeneous probe of oxidative stress in leaf tissues in the sense that increased MDA levels indicate either increased oxidation of ascorbate or decreased efficiency of ascorbate regeneration, or a combination of both.

  Japanese Society of Plant Physiologists, 1996, Plant and cell physiology, 37(8) (8), 1066 - 1072, English


• Inactivation Mechanism of Ascorbate Peroxidase at Low Concentrations of Ascorbate; Hydrogen Peroxide Decomposes Compound I of Ascorbate Peroxidase :

  Miyake Chikahiro, Asada Kozi

  One of the characteristic properties of ascorbate peroxidase (APX), which distinguishes it from guaiacol peroxidase, Cyt c peroxidase and glutathione peroxidase, is the rapid inactivation of the enzyme under conditions where an electron donor is absent. When thylakoid-bound APX (tAPX) in 100 μM ascorbate was diluted 500-fold with an ascorbate-depleted medium, the enzymatic activity was lost with half time of about 15 s. The inactivation of tAPX was suppressed under anaerobic conditions and also by the addition of catalase, but it was unaffected by the addition of superoxide dismutase. These observations suggest that hydrogen peroxide at nanomolar levels, produced by autooxidation of ascorbate at lower than micromolar levels, might participate in the inactivation of tAPX. The participation of hydrogen peroxide was confirmed by the inactivation of tAPX upon incubation with hydrogen peroxide under an-aerobic conditions. In the absence of ascorbate, the heme of the two-electron-oxidized intermediate of tAPX (designated Compound I) is decomposed by hydrogen peroxide. Thus, the instability of Compound I to hydrogen peroxide is responsible for the inactivation of APX when ascorbate is not available for Compound I and the enzyme cannot turnover.

  Japanese Society of Plant Physiologists, 1996, Plant and cell physiology, 37(4) (4), 423 - 430, English


• Ferredoxin-dependent and antimycinA-sensitive reduction of cytochrome b559 in maize thylakoids:Menadiol-reducible, low-potential cytochrome b559 isferredoxin-quinone reductase

  MIYAKE Chikahiro, SCHREIBER Ulrich, ASADA Kozi

  Mar. 1995, Plant and cell physiology, 36, S67, English


• Ferredoxin-Dependent and Antimycin A-Sensitive Reduction of Cyiochrome b-559 by Far-Red Light in Maize Thylakoids : Participation of a Menadiol-Reducible Cytochrome b-559 in Cyclic Electron Flow : ENVIRONMENTAL AND STRESS RESPONSES : MEMBRANES AND BIOENERGETICS :

  MIYAKE Chikahiro, SCHREIBER Ulrich, ASADA Kozi

  Thylakoids from mesophyll cells of maize showed a high rate of the ferredoxin (Fd)-dependent and antimycin A (AntiA)-sensitive cyclic electron flow as determined by the quenching of 9-aminoacridine fluorescence which indicates the formation of A pH across the membranes. Spectrophotometric survey of the thylakoids showed the reduction of a Cyt having an a-peak at 559 nm [Cyt b-559(Fd)] by far-red light, which depended on Fd and was sensitive to AntiA. Dose dependencies of Fd and AntiA on the photoreduction of Cyt b-559(Fd) were the same as those of the formation of ΔpH. Cyt b-559(Fd) occurred in an oxidized form even in the presence of ascorbate and was reduced by far-red light. In darkness, it was reduced only by menadiol (E_= -10 mV). Thus, Cyt b-559(Fd) was distinguished from Cyt b-559 in the PSII complex by its low redox potential. The present results indicate that Cyt b-559(Fd) mediates electron transfer from Fd to plastoquinone during Fd-dependent cyclic electron flow around PSI.

  Japanese Society of Plant Physiologists, 1995, Plant and cell physiology, 36(4) (4), 743 - 748, English


• Photoactivation of the Electron Flow from NADPH to Plastoquinone in Spinach Chloroplasts : GROWTH AND DEVEROPMENT : ENVIRONMENTAL AND STRESS RESPONSES :

  MANO Junichi, MIYAKE Chikahiro, SCHREIBER Ulrich, ASADA Kozi

  Intact chloroplasts from spinach showed a transient increase in Chl fluorescence after saturating illumination with actinic light and its yield depended on the duration of illumination and the intensity of the actinic light (AL). The increase was partially suppressed when antimycin A was added immediately after termination of the AL. The inhibited fluorescence increase, therefore, reflected the electron flow from the reductant(s) that had accumulated during the actinic illumination to the plastoquinone (PQ) pool via ferredoxin and the antimycin A-sensitive Cyt b-559 [Miyake et al. (1995) Plant Cell Physiol. 36: 743]. Addition of dihydroxyacetone phosphate (DHAP) to chloroplasts caused the enhancement of the increase in fluorescence after AL, which was inhibited by antimycin A. Decay of the transiently raised fluorescence was retarded by 2-heptyl-4-hydroxyquinoline N-oxide and stigmatellin, suggesting that re-oxidation of the reduced PQ pool is coupled with the operation of Q-cycle. Although the activity of the stromal enzyme system that supplies NADPH on addition of DHAP was constant irrespective of light or darkness, the capacity of the intact chloroplasts to show a DHAP-dependent fluorescence increase had a limited lifetime after AL was turned off. This result suggests that the antimycin A-sensitive Cyt b-559 or ferredoxin-NADP reductase is activated by light and deactivated in the dark. In ruptured chloroplasts, the addition of NADPH increased the dark fluorescence yield only in the presence of Fd, which also was inhibited by antimycin A. Thus the photoregulatory mechanism of Cyt b-559 (Fd) in intact chloroplasts appeared to be lost when chloroplasts were ruptured.

  Japanese Society of Plant Physiologists, 1995, Plant and cell physiology, 36(8) (8), 1589 - 1598, English


• Ferredoxin-Dependent Photoreduction of the Monodehydroascorbate Radical in Spinach Thylakoids : ENVIRONMENTAL AND STRESS RESPONSES : PROTEINS, ENZYMES AND METABOLISM :

  MIYAKE Chikahiro, ASADA Kozi

  Thylakoid-bound and stromal ascorbate peroxidases scavenge the hydrogen peroxide that is photoproduced in PSI of chloroplast thylakoids. The primary oxidation product of ascorbate in the reaction catalyzed by ascorbate peroxidase, the monodehydroascorbate (MDA) radical, is photoreduced by thylakoids [Miyake and Asada (1992) Plant Cell Physiol. 33:541]. We have now shown that the photoreduction of MDA radical in spinach thylakoids is largely dependent on ferredoxin (Fd), as determined by the monitoring the MDA radical by electron paramagnetic resonance. Further, the reduced Fd generated by NADPH and Fd-NADP reductase could reduce the MDA radical at a rate of over 10^6 M^<-1> s^<-1>, indicating that the photoreduced Fd in PSI directly reduces the MDA radical to ascorbate. Photoreduction of NADP^+ by spinach thylakoids was suppressed by the MDA radical and conversely that of MDA radical was suppressed by NADP^+, indicating a competition between the MDA radical and NADP^+ for the photoreduced Fd in PSI. The ratio of the rate constant for the photoreduction of MDA radical to that for the photoreduction of NADP^+ was estimated to be more than 30 to 1. Thus, MDA radical is preferentially photoreduced as compared to NADP^+ From these results, we propose that the thylakoid-bound ascorbate peroxidase and the Fd-dependent photoreduction of MDA radical in PSI are the primary system for the scavenging of the hydrogen peroxide that is photoproduced in the thylakoids.

  Japanese Society of Plant Physiologists, 1994, Plant and cell physiology, 35(4) (4), 539 - 549, English


• Purification and Molecular Properties of the Thylakoid-Bound Ascorbate Peroxidase in Spinach Chloroplasts :

  MIYAKE Chikahiro, CAO Wan-Hong, ASADA Kozi

  The hydrogen peroxide that is photoproduced in thylakoids is scavenged by the thylakoid-bound ascorbate peroxidase (tAPX) [Miyake and Asada (1992) Plant Cell Physiol. 33: 541]. tAPX was purified from spinach thylakoids to homogeneity as judged by SDS-polyacrylamide gel electrophoresis, and its molecular properties were studied. Spinach tAPX was a monomer with a molecular weight of 40,000, which is about 10.000 higher than that of the stromal ascorbate peroxidase (sAPX) from spinach chloroplasts. tAPX cross-reacted with the antibody raised against sAPX from tea leaves, as determined by Western blotting, which also provided evidence for the higher molecular weight of tAPX from spinach thylakoids than that of tea sAPX. The amino acid sequence of the amino-terminal region of tAPX showed a low degree of homology to those of cylosolic APXs from spinach, pea and Arabidopsis thaliana, but a high degree of homology to that of stromal APX from tea. Thus, the amino-terminal region of tAPX seems not to be a domain required for binding of the enzyme to the thylakoid membranes. tAPX contained protoheme IX, as identified by its pyridine hemochromogen, and gave a Soret peak at 403 nm and 433 nm with an a band at 555 nm in its oxidized and reduced forms, respectively. Resembling sAPX but differing from cytosolic APX, tAPX showed high specificity for ascorbate as the electron donor. tAPX was inhibited by cyanide, thiol-modifying reagents, thiols and several suicide inhibitors, such as hydroxyurea and p-aminophenol.

  Japanese Society of Plant Physiologists, 1993, Plant and cell physiology, 34(6) (6), 881 - 889, English


• Thylakoid-Bound Ascorbate Peroxidase in Spinach Chloroplasts and Photoreduction of Its Primary Oxidation Product Monodehydroascorbate Radicals in Thylakoids : PROTEINS, ENZYMES AND METABOLISM : MEMBRANES AND BIOENERGETICS :

  Miyake Chikahiro, Asada Kozi

  Ascorbate peroxidase, a key enzyme for the scavenging of hydrogen peroxide in chloroplasts, was found in a thylakoid-bound form in spinach chloroplasts at comparable activity to that in the stroma. The activity of peroxidase was detectable in the thylakoids only when prepared by an ascorbate-containing medium, and enriched in the stroma thylakoids. The thylakoid enzyme was not released from the membranes by either 2 mM EDTA, 1 M KCl, 2 M NaBr or 2 M NaSCN, but was solubilized by detergents. Enzymatic properties of the thylakoid-bound ascorbate peroxidase were very similar to those of the stromal ascorbate peroxidase. Thylakoid-bound ascorbate peroxidase could scavenge the hydrogen peroxide either added or photoproduced by the thylakoids. No photoreduction of hydrogen peroxide was observed, however, in the thylakoids whose ascorbate peroxidase was inhibited by KCN and thiol reagents or inactivated by the treatment with ascorbate-depletion. The primary oxidation product of ascorbate in a reaction of ascorbate peroxidase, monodehydroascorbate (MDA) radical, was photoreduced in the thylakoids, as detected by the quenching of chlorophyll fluorescence, disappearance of EPR signals of the MDA radicals and the MDA radical-induced oxygen evolution. Thus, ascorbate is photoregenerated in the thylakoids from the MDA radicals produced in a reaction of ascorbate peroxidase for the scavenging of hydrogen peroxide.

  Japanese Society of Plant Physiologists, 1992, Plant and cell physiology, 33(5) (5), 541 - 553, English


• Scavenging of Hydrogen Peroxide in Prokaryotic and Eukaryotic Algae: Acquisition of Ascorbate Peroxidase during the Evolution of Cyanobacteria :

  Miyake Chikahiro, Michihata Fumi, Asada Kozi

  Ascorbate (AsA) peroxidase was found in six species of cyanobacteria among ten species tested. Upon the addition of H_2^<18>O_2 to the cells of AsA peroxidase-containing cyanobacteria, <16>^O_2 derived from water and <18>^O_2 derived from H_2<18>^O_2 Were evolved in the light. The evolution of <16>^O_2 was inhibited by DCMU and did not occur in the dark, but <18>^O_2 was evolved even in the dark or in the presence of DCMU. Similar light-dependent evolution of <16>^O_2 Was observed in the cells of AsA peroxidase-containing Euglena and Chlamydomonas. However, the cells of AsA peroxidase-lacking cyanobacteria evolved only <18>^O_2 in either the light or dark. Furthermore, the quenching of chlorophyll fluorescence induced by hydrogen peroxide was observed only in the cells of the AsA peroxidase-containing Synechocystis 6803, and not in the cells of Anacystis nidulans which lacks AsA peroxidase. Thus, cyanobacteria can be divided into two groups, those that has and those that lacks AsA peroxidase. The first group scavenges hydrogen peroxide with the peroxidase using a photoreductant as the electron donor, and the second group only scavenges hydrogen peroxide with catalase.

  Japanese Society of Plant Physiologists, 1991, Plant and cell physiology, 32(1) (1), 33 - 43, English

• 蛍光分光法による酸素発生型光合成生物における光エネルギー調節機構に関する研究

  植野 嘉文, 嶋川 銀河, 藍川 晋平, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  2018年光化学討論会, Sep. 2018, Japanese, 関西学院大学・上ケ原キャンパス, Domestic conference

  Poster presentation


• 単細胞緑藻Chlorella variabilis における低CO2条件での光捕集機能調整

  植野 嘉文, 嶋川 銀河, 三宅 親弘, AKIMOTO SEIJI

  第9回日本光合成学会年会, 2018, Japanese, 仙台, Domestic conference

  Poster presentation


• 絶対蛍光強度測定による緑藻Chlorella variabilis におけるCO2条件に依存した光捕集機能調節の解明

  植野 嘉文, 嶋川 銀河, 藍川 晋平, 三宅 親弘, AKIMOTO SEIJI

  光合成セミナー2018：反応中心と色素系の多様性, 2018, Japanese, 神戸, Domestic conference

  Poster presentation


• 緑藻Chlamydomonas reinhardtii におけるCO2 に対する光捕集機能変化

  植野 嘉文, 嶋川 銀河, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  第58回日本植物生理学会年会, Mar. 2017, Japanese, 鹿児島大学郡元キャンパス, Domestic conference

  Poster presentation


• 高CO2 条件から低CO2 条件への移行に伴うシアノバクテリアの光合成初期過程の変化

  藤本 かおり, 嶋川 銀河, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  第58回日本植物生理学会年会, Mar. 2017, Japanese, 鹿児島大学郡元キャンパス, Domestic conference

  Poster presentation


• 異なる二酸化炭素濃度下で培養されたシアノバクテリアにおける光エネルギー捕集過程

  池田 志保, AIKAWA SHINPEI, 嶋川 銀河, MIYAKE CHIKAHIRO, KONDO AKIHIKO, AKIMOTO SEIJI

  第58回日本植物生理学会年会, Mar. 2017, Japanese, 鹿児島大学郡元キャンパス, Domestic conference

  Poster presentation


• 高濃度二酸化炭素条件下で培養したシアノバクテリアの光応答

  藤本 かおり, 嶋川 銀河, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  第10回分子科学討論会2016神戸, Sep. 2016, Japanese, 神戸ファッションマート, Domestic conference

  Poster presentation


• 絶対蛍光強度測定による緑藻Chlamydomonas reinhardtiiにおける光捕集機能変化の解明

  植野 嘉文, 嶋川 銀河, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  第24回 「光合成セミナー2016：反応中心と色素系の多様性」, Jul. 2016, Japanese, 龍谷大学深草キャンパス, Domestic conference

  Poster presentation


• 77 Kにおける蛍光の絶対強度測定 −シアノバクテリアの光応答−

  藤本 かおり, 嶋川 銀河, MIYAKE CHIKAHIRO, AKIMOTO SEIJI

  第24回 「光合成セミナー2016：反応中心と色素系の多様性」, Jul. 2016, Japanese, 龍谷大学深草キャンパス, Domestic conference

  Poster presentation


• 高等植物におけるalkenal/one oxidoreductase (AOR)の生理学的解析 植物も糖尿病を発症する

  齋藤 亮太, 伊福 健太郎, IKEDA KENICHI, 池田 加奈子, MIYAKE CHIKAHIRO

  日本土壌肥料学会関西支部会, 2013, Japanese, Domestic conference

  Oral presentation

• 光合成生物での、糖由来活性カルボニル化合物の生成・毒性および解毒メカニズムの解明

  三宅 親弘

  学術研究助成基金助成金／基盤研究(C), Apr. 2014 - Mar. 2017, Principal investigator

  Competitive research funding


• 活性酸素生成抑制システムの非破壊評価系の確立とフィールドへの応用～危機早期診断システムの構築～

  三宅 親弘

  国立研究開発法人科学技術振興機構, 戦略的創造研究推進事業（チーム型研究（CREST））, 2017, Principal investigator

  Competitive research funding


• 【CREST】活性酸素生成抑制システムの非破壊評価系の確立とフィールドへの応用～危機早期診断システムの構築～

  三宅 親弘

  国立研究開発法人科学技術振興機構, 戦略的創造研究推進事業（CREST）, 2016, Principal investigator

  Competitive research funding


• CREST「活性酸素生成抑制システムの非破壊評価系の確立とフィールドへの応用～危機早期診断システムの構築～」

  三宅 親弘

  科学技術振興機構, 戦略的創造研究推進事業 チーム型研究CREST, 2015, Principal investigator

  Competitive research funding


• 高ＣＯ２順化に必須の、糖アルデヒド・毒性化合物による細胞障害防御機構の全容解明

  三宅 親弘

  科学研究費補助金／新学術領域研究, Apr. 2012 - Mar. 2014, Principal investigator

  Competitive research funding


• 高ＣＯ２順化に必須の遺伝子探索とその機能解析：植物は、なぜ糖尿病を患わないのか？

  三宅 親弘

  科学研究費補助金／新学術領域研究, 2010, Principal investigator

  Competitive research funding


• 強光順化での、葉緑体チラコイド膜プラストキノン酸化システムの分子メカニズム解明

  三宅 親弘

  科学研究費補助金／基盤研究(C), 2009, Principal investigator

  Competitive research funding


• Research on the rate-limitting Factors affecting the activities of photosynthesis in leaves of tree plants

  KOBAYASHI Yoshichika

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), KYUSHU UNIVERSITY, 2002 - 2004

  Leaves of evergreen trees are characterized by the low activity of CO_2 uptake compared with leaves of deciduous trees and herbaceous plants. However, we found that there are no substantial differences among leaves of these plant species in the activities of electron transport (Je) and CO_2 assimilation (JCO_2), when the activities (Je and JCO_2) were compared with leaves containing similar levels of CO_2 at the carboxylation site in stroma (Cc). The results suggest that chloroplasts of evergreen tree leaves have high abilities of electron transport and CO_2 assimilation in spite of their very low activities of leaf photosynthesis evaluated as the activity of CO_2 uptake under illumination with saturating light in air containing 350 ppm CO_2. We, therefore, measured the photosynthetic parameters of attached leaves such as the stomatal and mesophyll conductance to CO_2 diffusion (gs and gm), the CO_2 concentrations in intercellular spaces and stroma (Ci and Cc), and the fluxes of electrons consumed by photosynthesis and photorespiration (JCO_2 and JPR). After the measurement, membrane lipids were isolated from the same leaves as used for the experiments, and the fatty acid composition was determined. A linear relationship was observed between the net activity of photosynthesis (JCO_2) and the mesophyll conductance, indicating that leaf photosynthesis depends on the mesophyll conductance (gm). A good correlation was also found between gm and the relative content of α-linolenic acid (18:3), and between gm and the relative content of palmitic acid (16:0). On the basis of these observations, several possible factors limiting the diffusion of CO_2 in leaf tissue of evergreen trees including Eucalyptus plants were determined.


• 菖蒲生葉で発見された新規な光合成電子伝達反応の分子機構とその生理的役割の解明

  三宅 親弘

  日本学術振興会, 科学研究費助成事業, 若手研究(B), 九州大学, 2001 - 2002

  平成13年度、光合成速度が小さく、過剰な光エネルギーに常にさらされている菖蒲の生葉において、チラコイド膜光化学系II(PSII)内循環的電子伝達反応(CEF-PSII)が機能し、過剰な光エネルギーの安全な散逸をおこなっていることを示唆する結果を、菖蒲チラコイド膜を用いて得た。本年度は、以下に述べるように、CEF-PSIIが、葉緑体で実際に機能していることおよび過剰な光エネルギーの散逸に機能していることをチラコイド膜を用いて明らかにした。モデル葉緑体として、ホウレンソウ生葉から葉緑体を単離した。光合成電子伝達反応速度を酸素吸収速度[V(O_2)]、PSIIの電子伝達速度をクロロフィル蛍光解析により得られるPSIIの量子収率[Φ(PSII)]により評価した。CEF-PSIIの活性発現には、チラコイド膜のΔpH形成を要する。光照射下の葉緑体に、プロトノフォアを添加し、ΔpHを消失させると、V(O_2)の増大が認められるが、Φ(PSII)は減少した。これは、葉緑体でも、光合成電子伝達反応に関係しない電子が、PSII内で流れているつまりCEF-PSIIが機能していることを示す。CEF-PSIIの活性は、光強度の増大とともに増加し、過剰な光エネルギー散逸能をもつthe water-water cycleの活性に匹敵した(平成14年論文報告)。次に、CEF-PSIIの生理機能を明らかにするために、電子受容体濃度およびΔpHを調節することによりV(O_2)の値およびCEF-PSII活性を変化させ、チラコイド膜を光照射した。CEF-PSIIが機能しない条件下では、チラコイド膜の光合成電子伝達活性は速やかに失われ、これはPSIIの光失活によるものであった。つまり、CEF-PSIIが、実際に過剰な光エネルギーの散逸に機能することが明らかになった(平成15年論文報告in press)。