Utsunomiya University

About: Utsunomiya University is a education organization based out in Utsunomiya, Japan. It is known for research contribution in the topics: Laser & Holography. The organization has 4139 authors who have published 6812 publications receiving 91975 citations. The organization is also known as: Utsunomiya daigaku.

Sulfur Kβ X-Ray Emission Bands and Valence-Band Structures of Transition-Metal Disulfides

Abstract: The sulfur K β emission spectra in fluorescence from FeS 2 , CoS 2 , NiS 2 (with pyrite structure) and 2H-MoS 2 (with layered structure) have been measured on a vacuum two-crystal spectrometer. Results are evaluated by comparing the sulfur K β emission spectra with the X-ray photoelectron spectra of the valence-band region for the transition-metal disulfides, with the sulfur L II, III emission spectra and with the recent electronic-structure calculations. A reasonable agreement is obtained between them. It is indicated that the sulfur 3 p -like valence bands of the metal disulfides are very broad and their upper parts overlap with the 3 d - or 4 d -like band of the metals.

Planteose as a storage carbohydrate required for early stage of germination of Orobanche minor and its metabolism as a possible target for selective control

Abstract: Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, as indicators of host roots within reach of the parasite's radicles. This unique germination process was focused on to identify metabolic pathways required for germination, and to design a selective control strategy. A metabolomic analysis of germinating seeds of clover broomrape, Orobanche minor, was conducted to identify its distinctive metabolites. Consequently, a galactosyl-sucrose trisaccharide, planteose (α-d-galactopyranosyl-(1→6)-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside), was identified as a metabolite that decreased promptly after reception of the germination stimulant. To investigate the importance of planteose metabolism, the effects of several glycosidase inhibitors were examined, and nojirimycin bisulfite (NJ) was found to alter the sugar metabolism and to selectively inhibit the germination of O. minor. Planteose consumption was similar in NJ-treated seeds and non-treated germinating seeds; however, NJ-treated seeds showed lower consumption of sucrose, a possible intermediate of planteose metabolism, resulting in significantly less glucose and fructose. This inhibitory effect was recovered by adding glucose. These results suggest that planteose is a storage carbohydrate required for early stage of germination of O. minor, and NJ inhibits germination by blocking the supply of essential glucose from planteose and sucrose. Additionally, NJ selectively inhibited radicle elongation of germinated seeds of Orobanchaceae plants (Striga hermonthica and Phtheirospermum japonicum). Thus, NJ will be a promising tool to develop specific herbicides to the parasites, especially broomrapes, and to improve our understanding of the molecular mechanisms of this unique germination.

Circadian rhythm of melatonin release from the photoreceptive pineal organ of a teleost, ayu (Plecoglossus altivelis) in flow-thorough culture

Abstract: In the present study, we tested whether the pineal organ of ayu (Plecoglossus altivelis), an osmerid teleost close relative of salmonids, harbours a circadian oscillator regulating rhythmic melatonin release using flow-through culture. The pineal organ maintained under light/dark cycles released melatonin in a rhythmic fashion with high levels during the dark phase. A circadian rhythm of melatonin release persisted in constant darkness for at least four cycles. Characteristics of the circadian rhythm (free-running period, phase and amplitude) exhibited small variations among cultures when the data was normalized, indicating that this system is sufficient for the analysis of the circadian rhythm both at qualitative and quantitative levels. Six-hour extension of the light phase from the normal onset time of the dark phase or exposure to constant light for 36 or 48 h before transfer to constant darkness significantly inhibited melatonin release. Phase shifts in the circadian rhythm of melatonin release were also observed. Thus, the ayu pineal organ contains all the three essential components of the circadian system (a circadian clock, the photoreceptor responsible for photic entrainment of the clock, and melatonin generating system as an output pathway). This system should provide a useful model for analysing the physiological and molecular basis of the vertebrate circadian system. In addition, further comparative studies using salmonids and related species including ayu will provide some insight into the evolution of the roles of the pineal organ in the vertebrate circadian system.

Photoemission Study of the Spectral Function of V2O3 in Relation to the Recent Quantum Monte Carlo Study

Abstract: Photoelectron energy distribution curves near the Fermi level have been measured on V 2 O 3 above and below the critical temperature of the metal-insulator transition. In insulating phase, the band gap was found to be about 0.2 eV, which is consistent with the other experimental results. A clear Fermi edge, which becomes sharp at lower temperature, is found in the metallic phase. The 3d spectral feature is discussed in relation to the recent quantum-Monte-Carlo calculation. Resonant photoemission shows the hybridization effect is also important for the spectral feature.