A5006683844- Photosynthetic Processes and Mechanisms
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Porphyrin and Phthalocyanine Chemistry
- Algal biology and biofuel production
- Welding Techniques and Residual Stresses
- Photochemistry and Electron Transfer Studies
- Advanced Fluorescence Microscopy Techniques
- Hemoglobin structure and function
- Engineering Applied Research
- Toxoplasma gondii Research Studies
- Light effects on plants
- Marine and coastal ecosystems
- Corrosion Behavior and Inhibition
- Textile materials and evaluations
- Telecommunications and Broadcasting Technologies
- Vestibular and auditory disorders
- Colorectal and Anal Carcinomas
- Biocrusts and Microbial Ecology
- Lichen and fungal ecology
- Neuroscience of respiration and sleep
- Obstructive Sleep Apnea Research
- Surfactants and Colloidal Systems
- Genetic factors in colorectal cancer
- Heat Transfer and Boiling Studies
Tohoku University
2016-2025
Graduate School USA
2016
Sendai University
2016
Daikin (Japan)
1999-2015
Daikin (United States)
2004-2015
Nagoya University
2004-2013
National Institute of Technology, Asahikawa College
2013
Akita University
1993-2011
University of Hyogo
2010
Japan Broadcasting Corporation (Japan)
2002-2009
The experimentally obtained time-resolved fluorescence spectra of photosystem II (PS II) core complexes, purified from a thermophilic cyanobacterium Thermosynechococcus vulcanus, at 5-180 K are compared with simulations. Dynamic localization effects excitons treated implicitly by introducing exciton domains strongly coupled pigments. Exciton relaxations within domain and transfers between on the basis Redfield theory generalized Förster theory, respectively. excitonic couplings pigments...
We have studied excited-state dynamics of "nonfluorescent" flavoproteins including riboflavin binding protein (RBP), d-amino acid oxidase benzoate complex (DAOB), and others by means femtosecond fluorescence up-conversion method observed ultrafast quenching for the first time. interpreted mechanisms these as due to electron transfer (ET) flavin chromophore (F) in excited electronic state from nearby tryptophan (Trp.NH) or tyrosine (Tyr.OH) residues placed nanospace (PNS), on basis their...
Journal Article Biochemical and Functional Characterization of BLUF-Type Flavin-Binding Proteins Two Species Cyanobacteria Get access Koji Okajima, Okajima *To whom correspondence should be addressed. Tel: +81-3-5454-6641, Fax: +81-3-5454-4337, E-mail: mikeuchi@bio.c.u-tokyo.ac.jp Search for other works by this author on: Oxford Academic PubMed Google Scholar Shizue Yoshihara, Yoshihara Yoshimasa Fukushima, Fukushima Xiaoxing Geng, Geng Mitsunori Katayama, Katayama Shoichi Higashi, Higashi...
To elucidate the dynamics and mechanisms of radiationless transitions from higher excited electronic states as well ultrafast intramolecular vibronic relaxation in porphyrin derivatives, we have studied fluorescence Zn-tetraphenylporphyrin (ZnTPP) Zn-diphenylporphyrin derivatives (ZnDPP) fs−ps time regimes by means up-conversion technique. Detailed measurements on ZnTPP ethanol demonstrated over whole spectral range 430 to 620 nm when S2 state. The constant (∼2.3 ps) single-exponential decay...
We evaluated the relationship between size of regional lymph nodes and presence metastasis in them rectal cancer. Of 1,064 46 specimens, 133 (13%) were found to have metastases. A half positive most negative ones less than 5 mm diameter. Therefore, we must find smaller diameter for assessment node metastasis. Although larger ones, there was no significant difference. However, when comparing relation their location, epi- pararectal 10 highly suggestive metastases, but not a reliable indicator...
Abstract Prasiola crispa , an aerial green alga, forms layered colonies under the severe terrestrial conditions of Antarctica. Since only far-red light is available at a deep layer colony, P. has evolved molecular system for photosystem II (PSII) excitation using with uphill energy transfer. However, basis underlying this remains elusive. Here, we purified light-harvesting chlorophyll (Chl)-binding protein complex from (Pc-frLHC) that excites PSII and revealed its ring-shaped structure...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTFirst Unequivocal Observation of the Whole Bell-Shaped Energy Gap Law in Intramolecular Charge Separation from S2 Excited State Directly Linked Porphyrin−Imide Dyads and Its Solvent-Polarity DependenciesNoboru Mataga, Haik Chosrowjan, Yutaka Shibata, Naoya Yoshida, Atsuhiro Osuka, Takeshi Kikuzawa, Tadashi OkadaView Author Information Institute for Laser Technology, Utsubo-Hommachi 1-8-4 Nishi-ku, Osaka 550−0004, Japan Department Chemistry,...
Photoinduced charge separation (CS) due to electron transfer from the S2 state of zinc porphyrin (ZP) a directly linked imide (I) has been studied by means femtosecond fluorescence up-conversion and femtosecond−picosecond transient absorption spectral measurements. decay curves ZP−I dyads in various solvents were all single-exponential, which accurate rate constants for CS reaction obtained. The whole bell-shaped energy-gap law (EGL) confirmed unambiguously polar tetrahydrofurane,...
We have studied excited-state dynamics of "nonfluorescent" flavoproteins by means the femtosecond fluorescence up-conversion method. interpreted ultrafast quenching mechanisms these as due to electron transfer or followed proton-transfer interactions between excited flavin chromophore and nearby tryptophan tyrosine residues placed in protein nanospace, on basis their X-ray structures. Comparisons time profiles spectral characteristics chromophores solutions with those environments suggested...
Proteins with a BLUF (sensor of blue light using flavin adenine dinucleotide) domain represent newly recognized class photoreceptors that is widely distributed in the genomes photosynthetic bacteria, cyanobacteria, and Euglena. Recently, Okajima et al. [Okajima, K., Yoshihara, S., Geng, X., Katayama, M. Ikeuchi, (2003) Plant Cell Physiol. 44 (Suppl), 162] purified protein Tll0078 encoded genome thermophilic cyanobacterium Thermosynechococcus elongatus BP-1 by expressing Escherichia coli. We...
The photosynthetic reaction is driven by the cooperation of two light-excited pigment-protein supercomplexes: photosystem II (PSII) and I (PSI). efficiency excitation PSs relies on exquisite organization their light-harvesting antenna under environmental fluctuations. However, since antenna-protein composition within cells remains elusive, in vivo events arising from variations cannot be accurately explored. Here, we implemented single-pixel excitation-emission spectroscopy Chlamydomonas 80...
In this study, we report the first observation of a near-infrared (NIR) emission band from all-inorganic CsPbBr3 and CsPb(Br/Cl)3 perovskite microcrystals. By means temperature- power-dependent NIR visible luminescence spectroscopy, demonstrate that fraction excited states in these materials relax through radiative transitions involving traps located deep within gap, leading to broadband emission. The quantum yield trap is quantitatively determined for time amounts approximately 0.3% at room...
Prasiola crispa is an aerial green alga grown in Antarctica and forms layered colonies under Antarctica's severe terrestrial conditions. While cells the deep layer can escape from physical damage to their photosynthetic proteins induced by cold, drought, strong sunlight, photosynthetically active radiation (400–700 nm) significantly decreases layers, leaving only far-red light. Our analysis has shown that P. absorbs light, about 708 nm, with long-wavelength absorbing Chls (LWCs), LWCs...
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTRhodopsin Emission in Real Time: A New Aspect of the Primary Event VisionHaik Chosrowjan, Noboru Mataga, Yutaka Shibata, Shuji Tachibanaki, Hideki Kandori, Yoshinori Shichida, Tetsuji Okada, and Tsutomu KouyamaView Author Information Institute for Laser Technology, Utsubo-Hommachi 1-8-4 Nishi-ku, Osaka 550, Japan Department Biophysics, Graduate School Science Kyoto University, Sakyo-ku, 601-01, Physics, Nagoya Furo-cho Chikusa-ku, 464-01,...
The number of pigments in single light-harvesting complexes (chlorosomes) were calculated by imaging chlorosomes a frozen buffer at cryogenic temperature with confocal laser fluorescence microscope and pigment extraction. Chlorosomes isolated from two types green photosynthetic bacteria Chlorobium (Chl.) tepidum Chloroflexus (Cfl.) aurantiacus individually imaged the medium. Each spot observed mainly came chlorosome was ascribable to self-aggregates bacteriochlorophyll (BChl) c molecules as...
In the development of single-molecule spectroscopy, simultaneous detection excitation and emission spectra has been limited. The fluorescence spectrum based on background-free signals is compatible with fluorescence-emission-based single molecules can provide insight into variations in input energy different terminal emitters. Here, we implement excitation–emission spectroscopy (SMEES) for photosystem I (PSI) via a cryogenic optical microscope. To this end, extended our line-focus-based...
The effect of the protein environment surrounding chromophores (protein nanospaces) on photoinduced ultrafast twisting in photoactive yellow (PYP) was investigated by comparing femtosecond−picosecond fluorescence dynamics wild type PYP with those chromophore aqueous solution as well nanospace modified site-directed mutagenesis. rate twisted state formation (the primary step trans → cis photoisomerization) demonstrated to be considerably enhanced compared solution. Moreover, results...
The effect of the protein environment surrounding a chromophore [protein nanospace (PNS)] on photoinduced ultrafast reaction (deprotonated p-coumaric acid covalently bonded to via thioester linkage) has been investigated by comparing femtosecond picosecond fluorescence dynamics wild-type (w-t) photoactive yellow (PYP) with those in aqueous solution as well various PNSs modified site-directed mutagenesis. decay are considerably accelerated compared solution. nonexponential w-t PYP 100 fs 10...
Light is absorbed by photosynthetic algal symbionts (i.e. zooxanthellae) and chromophoric fluorescent proteins (FP) in reef-building coral tissue. We used a streak-camera spectrograph equipped with pulsed, blue laser diode (50 ps, 405 nm) to simultaneously resolve the fluorescence spectra kinetics for both FP zooxanthellae. Shallow water (<9 m)–dwelling Acropora spp. Plesiastrea versipora specimens were collected from Okinawa, Japan, Sydney, Australia, respectively. The main emitted light...