Emi Yoshida, Akimasa Nakamura, Tadashi Watanabe,
Chlorophyll (Chl) a′, the C132-epimer of Chl a, is one of the two Chl molecules constituting the primary electron donor (P700) of photosystem (PS) I of a thermophilic cyanobacterium Synechococcus elongatus. To examine whether PS I of other oxygenic photosynthetic organisms in general contain one Chl a′ molecule in P700, the pigment composition of thylakoid membranes and PS I preparations isolated from red algae Porphyridium purpureum and Cyanidium caldarium was examined by reversed-phase HPLC with ...
Tópico(s): Porphyrin and Phthalocyanine Chemistry
2003 - Springer Nature | Analytical Sciences
Akimasa Nakamura, Masahiko Akai, Emi Yoshida, Takashi Taki, Tadashi Watanabe,
Chlorophyll (Chl) a ′, the C13 2 ‐epimer of Chl a , is a constituent of the primary electron donor (P700) of Photosystem (PS) I of a thermophilic cyanobacterium Synechococcus ( Thermosynechococcus ) elongatus , as was recently demonstrated by X‐ray crystallography. To determine whether PS I of oxygenic photosynthetic organisms universally contains one molecule of Chl a ′, pigment compositions of thylakoid membranes and PS I complexes isolated from the cyanobacteria T. elongatus and Synechocystis sp. PCC 6803, the ...
Tópico(s): Spectroscopy and Quantum Chemical Studies
2003 - Wiley | European Journal of Biochemistry
Akimasa Nakamura, Tomoyuki Suzawa, Yuki Kato, Tadashi Watanabe,
The redox potential of the primary electron donor P700, Em(P700/P700+), of Photosystem I (PSI) has been determined for 10 oxygenic photosynthesis organisms, ranging from cyanobacteria, red algae, green algae to higher plants, by spectroelectrochemistry with an optically transparent thin-layer electrode (OTTLE) cell to elucidate the scattering by as much as 150 mV in reported values of Em(P700/P700+). The Em(P700/P700+) values determined within error ranges of ±1–4 mV exhibited a significant species ...
Tópico(s): Electrochemical Analysis and Applications
2011 - Oxford University Press | Plant and Cell Physiology
Christopher E. J. Cordonier, Akimasa Nakamura, Kazuhiko Shimada, Akira Fujishima,
Photoacid generating ligands, 4-(2-nitrobenzy-loxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol, and indium tin and titanium complexes thereof, were synthesized. These metal complexes perform as positive-tone, directly photopatternable indium tin oxide (ITO) or titanium oxide film precursors. After exposure, acid-bearing selectively soluble complexes could be removed to give patterned films upon developing in aqueous base, which were transformable to the corresponding pattern-preserving ...
Tópico(s): Copper-based nanomaterials and applications
2011 - American Chemical Society | Langmuir
Christopher E. J. Cordonier, Akimasa Nakamura, Kazuhiko Shimada, Akira Fujishima,
Palladium, cobalt, and nickel in complex with photoacid-generating ligands, 4-(2-nitrobenzyloxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol, were prepared in solution. Films formed from the metal complex solutions perform as positive-tone, directly photopatternable palladium, cobalt, nickel oxide, or composite film precursors. After exposure, acid-bearing selectively soluble complexes could be removed to give patterned films upon developing in aqueous base, which were transformable ...
Tópico(s): Photochromic and Fluorescence Chemistry
2012 - American Chemical Society | Langmuir
Akimasa Nakamura, Tomoyuki Suzawa, Yuki Kato, Tadashi Watanabe,
The redox potentials of P700, the primary electron donor of photosystem (PS) I, of spinach and Thermosynechococcus elongatus were determined by means of spectroelectrochemistry with an error range of ±2–3 mV, to find that the redox potential of P700 in T. elongatus is lower by ca. 50 mV as compared with spinach. The shift in the P700 redox potential of PS I core particles prepared by harsh detergent treatments remained to within 10 mV for both organisms. These results show that the 50 mV difference ...
Tópico(s): Photoreceptor and optogenetics research
2005 - Wiley | FEBS Letters
Akimasa Nakamura, Tomoyuki Suzawa, Tadashi Watanabe,
Abstract Optimization of experimental conditions for spectroelectrochemistry with an optically transparent thin-layer electrode allowed us to determine the redox potential of spinach P700, the primary electron donor of photosystem I, to be +469 mV vs. SHE with significantly high reproducibility (±2 mV for 12 independent samples).
Tópico(s): Electrochemical sensors and biosensors
2004 - Oxford University Press | Chemistry Letters
Akimasa Nakamura, Tadashi Watanabe,
Reversed-phase HPLC conditions for separation of chlorophyll (Chl) a, Chl a′ (the C132-epimer of Chl a), pheophytin (Pheo) a (the primary electron acceptor of photosystem (PS) II), and phylloquinone (PhQ) (the secondary electron acceptor of PS I), have been developed. Pigment extraction conditions were optimized in terms of pigment alteration and extraction efficiency. Pigment composition analysis of light-harvesting complex II, which would not contain Chl a′ nor Pheo a, showed the Chl a′/Chl a ratio of ...
Tópico(s): Electrochemical Analysis and Applications
2001 - Springer Nature | Analytical Sciences
Akimasa Nakamura, Shuhei Tanaka, Tadashi Watanabe,
Normal-phase HPLC conditions have been developed for separating the C173 isoprenoid isomers, which are expected to be formed as biosynthetic intermediates of chlorophyll (Chl) a, Chl a′ (C132-epimer of Chl a), pheophytin (Pheo) a and protochlorophyll (PChl). The application of these conditions to pigment composition analysis of greening etiolated barley leaves allowed us to detect, for the first time, the C173 isomers of Chl a′, a possible constituent of the primary electron donor of photosystem (PS) ...
Tópico(s): Porphyrin and Phthalocyanine Chemistry
2001 - Springer Nature | Analytical Sciences
Akimasa Nakamura, Tadashi Watanabe,
The temporal evolution of pigment composition during greening of etiolated barley leaves was investigated by reversed‐phase HPLC with particular attention to chlorophyll (Chl) a ′ (C13 2 epimer of Chl a ), which had been detected by ourselves in photosystem (PS) I particles. At early stages of greening, the Chl a ′/Chl a molar ratio rapidly increased to a level more than twice that in mature leaves, then gradually leveled off, accompanied by a growth of the Chl b /Chl a ratio, to the mature level. After 3 ...
Tópico(s): Spectroscopy and Quantum Chemical Studies
1998 - Wiley | FEBS Letters
Akimasa Nakamura, Shinji Mizoguchi, Emi Yoshida, Yuki Kato, Tadashi Watanabe,
Abstract To expand the spectral window for the light-induced charge separation in photosystem (PS) I of oxygenic photosynthetic organisms artificially, Rhodamine B (RhB) was covalently linked to the solution-exposed surfaces of PS I. By introduction of RhB to PS I, the activity of light-induced charge separation for excitation wavelength at which the light absorption is dominated by RhB increased by about 1.8-fold, showing that RhB covalently attached to PS I can serve as the artificial light-harvesting ...
Tópico(s): Spectroscopy and Quantum Chemical Studies
2005 - Oxford University Press | Chemistry Letters
Christopher E. J. Cordonier, Kyohei Okabe, Yoshio Horiuchi, Akimasa Nakamura, K. Ishikawa, Shozo Seino, Shinsuke Takagi, Hideo HONMA,
A procedure for formation of catalytic SiO2 substrate adhesive layer patterns and selective electrochemical metal deposition on the catalyst images was investigated. A photoreactive solution containing a diazonaphthoquinone sulfonate ester and Ti and Cu complexes was developed to deposit Cu catalyst-TiO2 adhesive layer latent images on glass. Sub-micrometer/micrometer scale positive tone photoactive TiCu complex film patterns were formed using a conventional photolithography technique. The Cu ions ...
Tópico(s): Nanofabrication and Lithography Techniques
2017 - American Chemical Society | Langmuir
Christopher E. J. Cordonier, Akimasa Nakamura, Kazuhiko Shimada, Akira Fujishima,
Abstract The efficiency of positive-tone directly photo-patternable 4-(2-nitrobenzyloxycarbonyl)catechol and 4-(6-nitroveratryloxycarbonyl)catechol complexes of indium tin was improved by tuning the solubility of the complexes and by chelation of maltol as a cooperative photo-solvolytic component, such that films could be patterned at up to 4.88 mW·s/nm in terms of resultant indium tin oxide (ITO). Patterned indium tin complexes were thermally transformed to pattern shape preserved ITO by anisotropic ...
Tópico(s): Liquid Crystal Research Advancements
2012 - Elsevier BV | Thin Solid Films
Yanrong Zhang, Akimasa Nakamura, Yoshinori Kuroiwa, Yuki Kato, Tadashi Watanabe,
The redox potentials ( E ∘′ ) of P700 in intact and diethyl ether‐treated thylakoid membranes as well as native photosystem (PS) I particles from spinach and Thermosynechococcus elongatus have been measured by a spectroelectrochemistry with an error range of ±2–3 mV. Stepwise removal of antenna pigments by ether treatment caused distinct shifts of the E ∘′ value with increasing degree of water saturation in ether; negatively from +471 to +428 mV for spinach, but positively from +423 to +436 mV for T. elongatus . ...
Tópico(s): Spectroscopy and Quantum Chemical Studies
2008 - Wiley | FEBS Letters
Akimasa Masuda, Noboru Nakamura, Tsuyoshi Tanaka,
REE abundances in ten chondrites (nine falls and one find) were determined very accurately by mass-spectrometric stable isotope dilution techniques. All of the chondrites have different relative and absolute REE patterns. Except for Eu and, rarely, for Ce, the REE abundances in chondrites are smoothly fractionated from sample to sample. Notwithstanding differences in the abundances of common REE, four of five L6 chondrites have very similar absolute Eu abundances; their mutually-normalized REE patterns ...
Tópico(s): Astronomical and nuclear sciences
1973 - Elsevier BV | Geochimica et Cosmochimica Acta
Shigenori Higuchi, Akimasa Higashi, Toshiro Nakamura, Ichiro Matsuda,
Six cases of nutritional copper deficiency were identified in a nursery institute for severely handicapped patients. All had been on prolonged enteral feeding of a copper-deficient diet and all had abnormalities related to the copper deficiency. Two of them had leukopenia, with or without macrocytic and normochromic anemia. After the oral administration of copper, the clinical and laboratory observations including neutrophil counts and serum copper and ceruloplasmin levels showed a complete recovery. ...
Tópico(s): Potassium and Related Disorders
1988 - Lippincott Williams & Wilkins | Journal of Pediatric Gastroenterology and Nutrition
Akimasa Fukui, Takanori Nakamura, Hideho Uchiyama, Kishiko Sugino, Hiromu Sugino, Makoto Asashima,
There are several lines of evidence that activin is a crucial molecule for mesoderm induction in early Xenopus embryos. However, it is not known what kind and what amounts of activin proteins exist in cleavage stage embryos. Three isoforms of activins, A, AB, and B, were demonstrated to be present at least in part as a complex with abundant follistatin, an activin-binding protein, in early Xenopus embryos (stage 1-5). These results suggest that activin stored in eggs has an important role for mesoderm ...
Tópico(s): Reproductive Biology and Fertility
1994 - Elsevier BV | Developmental Biology
Jian Hua, Takeshi Hasebe, Akimasa Someya, Shinji Nakamura, Koichi Sugimoto, Isao Nagaoka,
To understand the expression of NADPH oxidase components during neutrophil maturation, we examined the expression of mRNAs and proteins for NADPH oxidase components, and the superoxide-producing activity using HL-60 cells incubated with dimethyl sulfoxide (DMSO). Northern blot and Western blot analyses revealed that gp91(phox), p67(phox), and p47(phox) were expressed after myelocyte stages, whereas p22(phox), p40(phox), and rac-2 were expressed from the promyelocyte stage. Furthermore, immunocytochemical ...
Tópico(s): Blood disorders and treatments
2000 - Oxford University Press | Journal of Leukocyte Biology
Satoko Isaka, Akimasa Someya, Shinji Nakamura, Kiyohito Naïto, Masahiko Nozawa, Naoki Inoue, Fumihito Sugihara, Isao Nagaoka, Kazuo Kaneko,
Collagen is an extracellular matrix protein present in the skin, tendon, cartilage and bone. Collagen peptides (CP) are produced by the hydrolysis of gelatin (heat-denatured collagen) by proteases and are utilized as a component of nutraceuticals. The current study investigated the effect of CP on the articular cartilage of OA by evaluating the serum levels of biomarkers (CTX-II for type II collagen degradation and CPII for type II collagen synthesis), histopathological changes (Mankin score, based ...
Tópico(s): Tendon Structure and Treatment
2017 - Spandidos Publishing | Experimental and Therapeutic Medicine
Naoko Okiyama, Sae Inoue, Akimasa Saito, Yoshiyuki Nakamura, Yosuke Ishitsuka, Yasuhiro Fujisawa, Rei Watanabe, Manabu Fujimoto,
Tópico(s): Dermatological and Skeletal Disorders
2018 - Oxford University Press | British Journal of Dermatology
Sae Inoue, Naoko Okiyama, Miwako Shobo, Sei‐ichiro Motegi, H. Hirano, Yukinobu Nakagawa, Akimasa Saito, Yoshiyuki Nakamura, Yosuke Ishitsuka, Yasuhiro Fujisawa, Rei Watanabe, Manabu Fujimoto,
Tópico(s): Eosinophilic Disorders and Syndromes
2018 - Oxford University Press | British Journal of Dermatology
Ahmed Hamdy, Kakuya Kitagawa, Yoshitaka Goto, Akimasa Yamada, Satoshi Nakamura, Masafumi Takafuji, Naoki Nagasawa, Hajime Sakuma,
Tópico(s): Advanced MRI Techniques and Applications
2018 - Springer Science+Business Media | The International Journal of Cardiovascular Imaging
Kazumasa Oya, Sae Inoue, Akimasa Saito, Yoshiyuki Nakamura, Yosuke Ishitsuka, Yasuhiro Fujisawa, Rei Watanabe, Shijima Taguchi, Manabu Fujimoto, Naoko Okiyama,
Tópico(s): Eosinophilic Disorders and Syndromes
2019 - Oxford University Press | Lara D. Veeken
Ryota Tanaka, Yuki Ichimura, Noriko Kubota, Akimasa Saito, Yoshiyuki Nakamura, Yosuke Ishitsuka, Rei Watanabe, Yasuhiro Fujisawa, Mirei Kanzaki, Seiya Mizuno, Satoru Takahashi, Manabu Fujimoto, Naoko Okiyama,
Abstract Use of immune checkpoint inhibitors that target programmed cell death-1 (PD-1) can lead to various autoimmune-related adverse events (irAEs) including psoriasis-like dermatitis. Our observations on human samples indicated enhanced epidermal infiltration of CD8 T cells, and the pathogenesis of which appears to be dependent on IL-6 in the PD-1 signal blockade-induced psoriasis-like dermatitis. By using a murine model of imiquimod-induced psoriasis-like dermatitis, we further demonstrated that ...
Tópico(s): Immunotherapy and Immune Responses
2020 - Nature Portfolio | Communications Biology
Ryota Tanaka, Yuki Ichimura, Noriko Kubota, Akimasa Saito, Yoshiyuki Nakamura, Yosuke Ishitsuka, Rei Watanabe, Yasuhiro Fujisawa, Seiya Mizuno, Satoru Takahashi, Manabu Fujimoto, Naoko Okiyama,
PD-1 is an immunoregulatory receptor that can bind PD-L1 or PD-L2 expressed on stimulated antigen-presenting cells. In this study, isolated antigen-presenting cells (macrophages and dendritic cells) were cultured with IFN-γ, IL-4, or IL-17A, and the expression of PD-L1 and PD-L2 was compared by flow cytometry. Strong upregulation of PD-L1 expression was observed on IFN-γ stimulation of both antigen-presenting cells as well as in response to IL-17A stimulation of macrophages compared with the expression ...
Tópico(s): Immune Cell Function and Interaction
2021 - Elsevier BV | Journal of Investigative Dermatology
Jian Hua, Takeshi Hasebe, Akimasa Someya, Shinji Nakamura, Koichi Sugimoto, Isao Nagaoka,
Tópico(s): Receptor Mechanisms and Signaling
2001 - Springer Science+Business Media | Inflammation Research
Natsuko I. Kobayashi, Keitaro Tanoi, Atsushi Hirose, Takayuki Saito, Akihiko Noda, Naoko Iwata, Akimasa Nakano, Satoru Nakamura, Tomoko Nakanishi,
The mineral composition of taro ( Colocasia esculenta (L.) Schott) was analyzed to develop a method to distinguish taro produced in Japan and China. The concentrations of 15 elements (Al, Ca, Cl, Mg, Mn, Br, Co, Cr, Cs, Fe, K, Na, Rb, Sc, Zn) were assayed using instrumental neutron activation analysis. The concentrations of NO(3)(-), SO(4)(2-), H(2)PO(4)(-), Cl(-), malate, and oxalate were measured by ion chromatography. The mean concentrations of H(2)PO(4)(-), Co, Cr, and Na significantly differed ( ...
Tópico(s): Pacific and Southeast Asian Studies
2011 - American Chemical Society | Journal of Agricultural and Food Chemistry
Noboru Nakamura, Akimasa Masuda,
Tópico(s): Planetary Science and Exploration
1973 - Elsevier BV | Earth and Planetary Science Letters
Kazuhiro Toyoda, Yuji Nakamura, Akimasa Masuda,
The chemical compositions of 140 deep-sea sediment samples collected in the Pacific were examined. The characteristic features of the abundances of REEs in the sediment samples, including pelagic red clay, calcareous ooze, and blue mud, are demonstrated especially by a variety of Ce anomalies in the shale-normalized REE pattern. Cerium abundances in blue mud samples showed little anomaly. Calcareous ooze showed a general negative Ce anomaly. The spatial distribution of the Ce anomaly in red clay ...
Tópico(s): Paleontology and Stratigraphy of Fossils
1990 - Elsevier BV | Geochimica et Cosmochimica Acta
Toshiro Nakamura, Akimasa Higashi, Sadamu Takano, Masanobu Akagi, Ichiro Matsuda,
Tópico(s): Autoimmune and Inflammatory Disorders
1988 - Springer Science+Business Media | Digestive Diseases and Sciences