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11.
We investigated the protein profiles of variously aged rat astrocytes in response to oxidative stress. After H2O2-exposure of cells at 100 microM for 30 min, the relative intensity of ten protein spots changed on two-dimensional (2-D) gels compared with control gels after silver staining. Matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS) analysis after in-gel digestion revealed that six of these spots corresponded to three kinds of proteins, each of which was composed of a protein and its modified form with a different isoelectric point (pI). These three proteins were identified as peroxiredoxins (PRDXs) II and III, and calpactin I light chain (p11). H2O2-exposure increased the intensity of the spot with lower pI and simultaneously decreased that of the spot with higher pI for both PRDXs II and III. In addition, the expression of annexin VII, S-adenosyl-L-homocysteine hydrolase, elongation factor II fragment (EF-II), and adenosine deaminase was increased by H2O2-exposure in astrocytes from variously aged rats. Using the Pro-Q Diamond staining, heat shock protein 60 kDa (Hsp 60) and alpha-tubulin were observed to be phosphorylated upon H2O2-exposure. While phosphorylation of alpha-tubulin was correlated positively with age, the changes in abundance of ten protein spots as described above were independent of age. These results suggest that aging does not suppress the responses aimed at limiting injury and promoting repair brought about by severe oxidative stress, and might affect cell dynamics including the formation of microtubules. 相似文献
12.
T Nakajima Y Takashima A Furuya Y Ozawa Y Kawashima 《Chemical & pharmaceutical bulletin》1990,38(6):1680-1683
Indomethacin (IM) sustained-release suppositories were prepared by the fusion method using sugar ester and polyethylene glycol 4000 (PEG). The suppositories were evaluated by in vitro release testing, X-ray analysis and in vivo absorption testing in rabbits. X-ray analysis showed that IM was amorphous in PEG-base suppositories. In a release test, slow-release was obtained when the sugar ester content of a suppository was 60%. The IM plasma level following the administration of the suppository was well sustained in the absorption test. The main slow-release mechanism is considered to be the release of IM from the matrix composed of sugar ester and PEG, which is represented by the Higuchi equation. A good correlation between the release test and the absorption test was obtained. It is considered that the amorphous state of IM in this type of sustained-release suppository would enhance the release and absorption of IM in the rectum of the rabbit, whose rectal fluid volume is small. 相似文献
13.
Masaki Takeguchi Kazutaka Mitsuishi Miyoko Tanaka Kazuo Furuya 《Microscopy and microanalysis》2004,10(1):134-138
About 1 monolayer of palladium was deposited onto a silicon (111) 7 x 7 surface at a temperature of about 550 K inside an ultrahigh vacuum transmission electron microscope, resulting in formation of Pd2Si nanoislands and a 1 x 1 surface layer. Pd clusters created from an excess of Pd atoms on the 1 x 1 surface layer were directly observed by in situ plan view high-resolution transmission electron microscopy. When an objective aperture was introduced so that electron diffractions less than 0.20 nm were filtered out, the lattice structure of the 1 x 1 surface with 0.33 nm spacing and the Pd clusters with a trimer shape were visualized. It was found that image contrast of the 1 x 1 lattice on the specific height terraces disappeared, and thereby an atomic structure of the Pd clusters was clearly observed. The appearance and disappearance of the 1 x 1 lattice was explained by the effect of the kinematical diffraction. It was identified that a Pd cluster was composed of three Pd atoms without a centered Si atom, which is consistent with the model proposed previously. The feature of the Pd clusters stuck at the surface step was also described. 相似文献
14.
Masayoshi Nakasako Masamitsu Wada Satoru Tokutomi Kotaro T. Yamamoto Jun Sakai Mikio Kataoka Fumio Tokunaga † Masaki Furuya 《Photochemistry and photobiology》1990,52(1):3-12
Abstract— The quaternary structure of pea phytochrome type I (PI) dimer in the red-light-absorbing form was studied by small-angle X-ray scattering (SAXS) technique and rotary-shadowing electron microscopy. Structural parameters for PI 114 kDa chromopeptide dimer and its tryptically digested N-terminal 59 kDa chromopeptide monomer, such as average electron density, molecular volume and the second moment of electron density distribution, were determined in terms of SAXS using the contrast variation method. Furthermore, by means of model simulation for the scattering profiles of the chromopeptides, most plausible structural models for both peptides were constructed. The distance between the chromophoric domains was estimated to be about 70 A in the resultant model for 114 kDa chromopeptide dimer. Furthermore, the model was consistent with the electron-micrographic images of both the intact PI dimer and the PI 114 kDa chromopeptide dimer, so that the N-terminal 7 kDa fragment did not significantly contribute the low-resolution images of the dimer. 相似文献
15.
The microwave acid digestion method was applied to the decomposition of rock samples and optimum conditions were investigated. Samples of 10–100 mg were decomposed by changing the amount and composition of acid, heating time and number of reheating steps and then the concentrations of Si, Fe, Mn, Na, K and Mg in these samples were measured. The concentrations agreed with reported values when 10 mg of sample were decomposed by heating for 60 s with 0.3 ml of concentrated HNO3 and 0.1 ml of concentrated HF. Similarly, 100 mg of sample were also decomposed successfully by heating for 45–110 s with 0.3–1.0 ml of concentrated HNO3 and 0.4–0.7 ml of concentrated HF. It is concluded that the microwave acid digestion method decomposes rock samples with a very short heating time and with small amount of reagents compared with methods using conventional sealed PTFE vessels, which require several hours for the heating step and several millilitres of reagents. 相似文献
16.
Satoshi ObikaJyun-ichi Andoh Mayumi OnodaOsamu Nakagawa Akiko HirotoTomomi Sugimoto Takeshi Imanishi 《Tetrahedron letters》2003,44(28):5267-5270
A novel bridged nucleic acid monomer, 3′-amino-3′-deoxy-5-methyl-3′-N,4′-C-methyleneuridine, was successfully synthesized via a useful and convenient azetidine ring formation under Staudinger's conditions. A 1H NMR experiment and a PM3 calculation revealed that the sugar moiety of the novel bridged nucleic acid monomer, 3′-amino-3′,4′-BNA, was restricted to S-type conformation. 相似文献
17.
Application of the muramyldipeptide derivative B30-MDP to liposomal vaccines will aid in the development of improved high immunogenicity vaccines. To give full play to the effectiveness of B30-MDP as a liposomal vaccine, it is important to evaluate the effect of cholesterol, dimyristoylphosphatidylcholine (DMPC) or distearoylphosphatidylcholine (DSPC) incorporation on the chemical stability of B30-MDP and physicochemical properties of B30-MDP/lipid mixed vesicles from the view point of pharmaceutics.The observed degradation rate constants of B30-MDP by hydrolysis in B30-MDP/cholesterol mixed vesicles were increased with increasing concentration of cholesterol, however, those in B30-MDP/DMPC and B30-MDP/DSPC mixed vesicles were unchanged with increasing concentration of DMPC and DSPC. The degradation behavior of B30-MDP was then compared with physicochemical properties of B30-MDP/lipid mixed vesicles, such as membrane fluidity and particle size. It was apparent that the degradation of B30-MDP in B30-MDP/cholesterol mixed vesicles was influenced by the particle size, but not by the fluidity of the membranes. In the case of B30-MDP/phospholipid mixed vesicles, MDP/phospholipid mixed vesicles, the degradation of B30-MDP was not influenced by either the membranes' fluidity or the particle size of the mixed vesicles.It is considered that the degradation of B30-MDP in the mixed vesicles is dependent on the membrane state, and the addition of cholesterol to B30-MDP vesicle inhibits the mutual interaction of MDP regions, whereas the addition of phospholipids hardly influences the mutual interaction of MDP regions, possibly owing to phase separation between B30-MDP and phospholipids. 相似文献
18.
Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) (Eu[2,3-Nc(SC12H25)8]2, 1) and bis(tetra-tert-butyl-2,3- naphthalocyaninato)europium(III) (Eu[2,3-Nc(t-Bu)4]2, 2) have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3.H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV-visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2-->2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = -0.28 V (for 2) and -0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = -0.61, -1.64, -1.97, and -2.42 V, and for 1 they were observed at E1/2 = -0.62, -1.60, -1.86, and -2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared. 相似文献
19.
Miyuki Narita Fumio Hamada Mayumi Sato Iwao Suzuki Tetsuo Osa 《Journal of inclusion phenomena and macrocyclic chemistry》1999,34(4):421-430
Flexible hosts, 6A,6B-; 6A,6C-; 6A,6D-; and 6A,6E-bis dansylglycine-modified -cyclodextrins (-1, -2, -3, and -4, respectively) have been synthesized as a sensing molecule for organic guests including terpenoids and bile acids. These host compounds show a pure monomer fluorescence whose intensity is decreased or enhanced upon addition of guest species. The value I/I0, where I and I0 are fluorescence intensities in the presence and absence of a guest and I is I0- I, was used as a parameter of sensitivity. These hosts exhibit highly sensitive and selective molecular recognition ability, particularly, for lithochoic acid, chenodeoxycholic acid, and ursodeoxycholic acid. The behaviors of the appended moieties of these hosts when host–guest complexation occurs are studied by induced circular dichroism (ICD) spectra and fluorescence spectral change on accommodation of a guest. The ICD pattern of these hosts alone or on accommodation of a guest is very similar, indicating that the behavior of the appended moieties are very similar. The guest-induced variations in the fluorescence or ICD intensity suggest that the appended moieties act as a hydrophobic cap that enables the cyclodextrin to form 1 : 1 host–guest complexes. 相似文献
20.
Yasunori Inoue Hiro-o Hamaguchi Kotaro T. Yamamoto Mitsuo Tasumi Masaki Furuya 《Photochemistry and photobiology》1985,42(4):423-427
Abstract— Fluorescence spectra of native rye phytochrome were determined under different light conditions at liquid nitrogen temperature. Fluorescence spectrum of the red-light-absorbing form (Pr) had a major peak at about 685 nm (14 600 cm−1 ) and a broad sub-peak at about 515 nm (19 400 cm−1 ). The peak height at 685 nm was reduced by irradiation with monochromatic light of 640 nm, and a new peak became obvious at about 702 nm (14250 cm−1 ). This spectral change was almost completely reversed by subsequent irradiation with 700-nm light. Fluorescence spectrum of the photoequilibrium mixture of Pr and far-red-light absorbing form under continuous red light showed a sharp peak at about 685 nm having a peak height ca. 12% of Pr, and a broad sub-peak at about 508 nm (19 700 cm−1 ). Light of 730 nm did not reduce the peak height at about 685 nm but induced a new shoulder at about 699 nm (14300 cm−1 ). Monochromatic light of 640 and 700 nm given following the light of 730 nm could not reverse the spectral change at 699 nm induced by the irradiation with 730-nm light. Fluorescence spectrum of Pr in partially degraded phytochrome was similar to that in native phytochrome but the peak position in the red region was shifted by about 5 nm (100 cm−1 ) to the blue. 相似文献