Localization of TCA cycle dehydrogenases in the mitochondria

The site of localization of TCA cycle dehydrogenases in mitochondria has been investigated by observing the dehydrogenase activities and fine structure of the fractionated samples after freezing and thawing or sonication of beef heart and rat liver mitochondria. 1. In the sonicated mitochondria, activities of malic and isocitric dehydrogenases were highest in the supernatant fraction centrifuged at 198,000 x g for 60 minutes, while the specific activity of a-ketoglutaric dehydrogenase was higher in the fluffy or residue fraction. The distribution of the activity of pyruvic dehydrogenase was similar to that of a-ketoglutaric dehydrogenase. 2. In a sucrose density gradient fractionation of the fluffy fraction obtained by centifugation of sonicated mitochondria at 198, 000 x g for 60 minutes, the activities of malic and pyruvic dehydrogenase were observed in the top (or low density) layer in the form of fine particles, while that of a-ketoglutaric dehydrogenase was observed in the middle (or medium density) layers in the form of aggregates of fine particles and membranous fragments. 3. In the samples fractionated after freezing and thawing of mitochondria, which were considered to be a relatively mild disruption, the specific activity of a-ketoglutaric dehydrogenase was higher in the residue (submitochondria) fraction than that in the supernatant fraction (centrifuged at 144,000 x g, 30 minutes), and the activity of malic dehydrogenase still remained significantly high in the residue fraction. 4. It was deduced that the TCA cycle dehydrogenases could be localized in the matrix of the mitochondria by a loose binding to the inner membrane.</p

Thermal properties of [Cr(NH3)6](BF4)3[Cr(NH_3)_6](BF_4)_3 studied by adiabatic and relaxation calorimetry

Four (solid–solid) phase transitions were detected in the temperature range of (9 to 300) K in polycrystalline [Cr(NH3)6](BF4)3 at TC1 = 240.7 K, TC2 = 108.0 K, TC3 = 91.9 K, and TC4 = 61.3 K by adiabatic calorimetry. The measurements by relaxation calorimetry were followed on lowering temperature from 20 K down to 0.35 K under six different external magnetic field values (9, 7, 5, 3, 1 and 0) T. For non-zero values of applied magnetic field well-defined Schottky anomaly appears. Magnetic heat capacity was calculated assuming the zero-field splitting for the decoupled Cr(III) ions. There is no discrepancy between the observed and calculated values. Isothermal magnetization curve recorded up to 5 T was measured at temperature of 1.8 K

Gradual crossover in molecular organization of stable liquid H2O at moderately high pressure and temperature

Using the literature raw data of the speed of sound and the specific volume, the isothermal compressibility, κT, a second derivative thermodynamic quantity of G, was evaluated for liquid H2O in the pressure range up to 350 MPa and the temperature to 50 ºC. We then obtained its pressure derivative, dκT/dp, a third derivative numerically without using a fitting function to the κT data. On taking yet another p-derivative at a fixed T graphically without resorting to any fitting function, the resulting d2κT/dp2, a fourth derivative, showed a weak but clear step anomaly, with the onset of the step named point X and its end point Y. In analogy with another third and fourth derivative pair in binary aqueous solutions of glycerol, dαp/dxGly and d2αp/dxGly2, at 0.1 MPa (αp is the thermal expansivity and xGly the mole fraction of solute glycerol) in our recent publication [J. Solution Chem. 43, 663-674 (2014); DOI:10.1007/s10953-013-0122-7], we argue that there is a gradual crossover in the molecular organization of pure H2O from a low to a high p-regions starting at point X and ending at Y at a fixed T. The crossover takes place gradually spanning for about 100 MPa at a fixed temperature. The extrapolated temperature to zero p seems to be about 70 – 80 °C for points X and 90 – 110 °C for Y. Furthermore, the mid-points of X and Y seem to extrapolate to the triple point of liquid, ice Ih and ice III. Recalling that the zero xGly extrapolation of point X and Y for binary aqueous glycerol at 0.1 MPa gives about the same T values respectively, we suggest that at zero pressure the region below about 70 °C the hydrogen bond network is bond-percolated, while above about 90 ºC there is no hydrogen bond network. Implication of these findings is discussed

Non-Invasive Brain Stimulation (TMS/tDCS) and Rehabilitation for Stroke and Parkinson’s

The aim of this study was to clarify and compare the efficacies of rehabilitation using transcranial direct current stimulation (tDCS) and continuous theta burst stimulation (cTBS), a form of repetitive transcranial magnetic stimulation (rTMS), in convalescing stroke and Parkinson’s disease patients. For both types of stimuli, kinetic analysis and performance analysis of upper limb motor paralysis and gait analysis showed an increase in speed of movement, and an improvement in performance was observed. Both stimuli resulted in significant improvement compared with a sham stimulus. Change in speed of movement and performance was observed with both tDCS and cTBS, but there was not a significantly large difference between the stimuli. Improved movement due to reduction of excessive tension caused by spasticity was observed. In patients with Parkinson’s disease, gait speed and step length were increased. It is suggested that performance was improved because movement became smoother. The efficacy of tDCS and cTBS in patients with motor disorders caused by stroke or Parkinson’s disease will probably be further improved when combined with physical therapy

イオン液体ゲートのグラフェン電界効果トランジスタによるガスセンシングの研究

学位の種別:課程博士University of Tokyo(東京大学

Adsorption behaviour of the binary mixtures of octane and nonane at sub-monolayer coverage on graphite

The behaviour of binary mixtures of octane and nonane adsorbed on graphite has been investigated with a combination of adiabatic calorimetry and neutron di†raction. In contrast to the eutectic behaviour of monolayers of these materials at higher coverages, this combination of alkanes is found to form mixed crystals on the surface over an extensive composition range at the sub-monolayer coverages investigated here. In the mixed phase the shorter octane molecules are incorporated into the lattice of the longer nonane molecules. This incorporation occurs despite pure octane and nonane monolayers having di†erent symmetries and is attributed to the expanded nature of the submonolayer phases, relative to higher coverage monolayers, providing room for mixed crystal formation

The crystalline structures of the even alkanes hexane, octane, decane, dodecane and tetradecane monolayers adsorbed on graphite at submonolayer coverages and from the liquid

Neutron and X-ray diffraction have been used to structurally characterise the crystalline monolayer structures of hexane, octane, decane, dodecane and tetradecane adsorbed on graphite at sub-monolayer coverages and when coexisting with liquid alkane. The structures of all the molecules investigated at both coverages and low temperatures are isomorphous with rectangular unit cells of plane group pgg containing two molecules per cell. In both high- and low-coverage structures the molecules have their extended axes parallel to the surface. The plane of the carbon skeleton is found to be parallel to the graphite surface. The monolayers at sub-monolayer coverages are interpreted as uniaxially commensurate while those monolayers coexisting with the liquid are fully commensurate. Dodecane and tetradecane are exceptional: dodecane forms additional phases at high temperatures just prior to melting, at both low and high coverages. In these structures the molecules in the unit cell are parallel to each other with plane group cmm. Tetradecane only forms a single phase at high coverages in which the molecules appear to be parallel and upright, similar to the dodecane high temperature, high coverage phase

Relationship between Glutamate Accumulation and Ethylene Synthesis in Tomato Fruit during Ripening

The effect of ethylene on the accumulation of glutamate in the fruit of normal tomato ('Rutgers' and 'Momotaro')and ripening inhibitor mutant (rin) tomato(Lycopersicon esculentum Mill.) during ripening was investigated.As fruit ripening progresse,glutamate content in the fruit pericarp tissue increased greatly in 'Rutgers' but remained low and constant level in rin tomato.Glutamine and γ-aminobutyric acid contents decreased gradually during ripening in both 'Rutgers'and rin fruit.Relatively high activities of glutamate dehydrogease,glutamate synthase and glutamine synthetase were detected throughout fruit ripening in both varieties,whereas no relationship was observed between glutamate content and the enzyme activieies.Treatment of 'Momotaro'fruit with diazocyclopentadience,an inhibitro of ethylene action,inhibited the increase in ethylene production and glutamate accumlation which are associated with fruit ripening,suggesting that glutamate accumlation may be mediated through ethylene.However,glumamate content in rin fruit treatde with exogenous ethylene remained low and unchanged uitil after four days.The results indicate that accumulation of glutamete in tomato fruit is likely to be related to the ripening process apart from the direct role of ethylene.トマト果実の成熟に伴うグルタミン酸蓄積とエチレンとの関係を’Rutgers’、’桃太郎’およびrinを用いて調べた。1.’Rutgers’果実では、追熟に伴ってグルタミン酸含有が急激に増加したが、rin果実ではほとんど変化しなかった。グルタミンとγ-アミノ酪酸含量は両果実ともに追熟に伴って減少した。2.グルタミン酸代謝関連酵素として、グルタミン酸脱水素酵素、グルタミン酸合成酵素およびグルタミン合成酵素の追熟中の活性変化を調べたところ、’Rutgers’およびrin果実ともに高い活性を示した。3.’桃太郎’果実にDACP処理すると、追熟の進行に伴うエチレン生成の増加が抑制され、同時にグルタミン酸の蓄積を誘導しなかったが、6日後には増加した。5.以上のことより、トマト果実の成熟に伴うグルタミン酸の蓄積はエチレン生成によるものではなく、成熟に伴う現象であるように思われた