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21.
Jang MJ Lee MJ Park HY Bae YS Min DS Ryu SH Kwak JY 《Experimental & molecular medicine》2004,36(2):172-178
Agents that elevate cellular cAMP are known to inhibit the activation of phospholipase D (PLD). We investigated whether PLD can be phosphorylated by cAMP-dependent protein kinase (PKA) and PKA-mediated phosphorylation affects the interaction between PLD and RhoA, a membrane regulator of PLD. PLD1, but not PLD2 was found to be phosphorylated in vivo by the treatment of dibutyryl cAMP (dbcAMP) and in vitro by PKA. PKA inhibitor (KT5720) abolished the dbcAMP-induced phosphorylation of PLD1, but dibutyryl cGMP (dbcGMP) failed to phosphorylate PLD1. The association between PLD1 and Val14RhoA in an immunoprecipitation assay was abolished by both dbcAMP and dbcGMP. Moreover, RhoA but not PLD1 was dissociated from the membrane to the cytosolic fraction in dbcAMP-treated cells. These results suggest that both PLD1 and RhoA are phosphorylated by PKA and the interaction between PLD1 and RhoA is inhibited by the phosphorylation of RhoA rather than by the phosphorylation of PLD1. 相似文献
22.
Tokuda N Sasaki N Watanabe H Miki K Yamasaki S Hasunuma R Yamabe K 《The journal of physical chemistry. B》2005,109(26):12655-12657
Electroless deposition of Ag on atomically flat H-terminated Si(111) surfaces in aqueous alkaline solutions containing Ag ions produced two different sizes of Ag nanowires along atomic step edges: (1) a narrow nanowire of 10 nm in width and 0.5 nm in height and (2) a wide nanowire of 35 nm in width and 11 nm in height. The narrow and wide nanowires were formed by immersion in the solutions containing less than 1 ppb and 8 ppm dissolved-oxygen concentrations, respectively. This result indicates that the dissolved oxygen initiates the formation of Ag nucleation sites and that the fabrication method has a possibility of controlling the size of Ag nanowires. 相似文献
23.
Tojino M Uenoyama Y Fukuyama T Ryu I 《Chemical communications (Cambridge, England)》2004,(21):2482-2483
Free-radical carbonylation of omega-alkynylamines with tributyltin hydride gives a mixture of alpha-methylene lactams and alpha-stannylmethylene lactams. Nucleophilic addition of an internal amino group to the carbonyl group of alpha-ketenyl radicals is proposed as the cyclization step. The subsequent unusual 1,4-H shift from the resulting 1-hydroxyallyl radical, followed by elimination of the beta-tributyltin radical leads to the formation of alpha-methylene lactams. 相似文献
24.
Poly(1,4-dimethyl-6-vinylnaphthalene) and poly(1,2,4-trimethyl-6-vinylnaphthalene) react with singlet oxygen to give corresponding endoperoxide polymers which on warming generate singlet oxygen efficiently. Singlet oxygenations by the use of these polymers have been described. 相似文献
25.
Some photosensitive molecules, such as p-N,N′-dimethylaminobenzoic acid (DMABA), Nile Red, heteropolytungstic acid (H3PW12O40, HPA) and metalloporphyrins, have been entrapped onto nano-scale pores or channels of TiO2-modified Y-Zeolite (TiO2-Y-Zeolite) and MCM41 (TiO2-MCM41) and their excited-state intermediates have been characterized in terms of the excited-state dynamics by using laser spectroscopic techniques. Through these studies, it has been found that the photo-induced electrons are generated from the intramolecular charge transfer (ICT) state of DMABA, Nile Red or metalloporphyrin (MnTPP(Cl)), followed by transferring to the TiO2-Y-Zeolite or TiO2-MCM41 more efficiently as compared to the bulk TiO2, NaY-Zeolite or MCM41. The efficient photoinduced interfacial electron transfer causes the rapid formation of radicals of those photosensitive molecules (a few tens ps). It has been also found that these photophysical properties can be applied to develop the new photocatalyst as observed by the efficient photocatalytic activities of the DMABA or Nile Red-entrapped TiO2-Y-Zeolites for the photoreduction of an azo-dye such as Methyl Orange in water. On the other hand, in case of HPA-entrapped TiO2-Y-zeolite, the electron generated from the excited-state TiO2 is transferred to HPA, followed by formation of the reduction product, heteropoly blue (HPB) which is also generated by UV irradiation of HPA. This electron transfer is analogous to the Z-scheme mechanism of plant photosynthetic systems showing two photon reactions. Because of this photoelectron transfer mechanism, the HPA-entrapped TiO2-Y-zeolite has demonstrated the synergistic enhancement of the photocatalytic decomposition of Methyl Orange and hydrogen generation from photolysis of water. 相似文献
26.
S. C. Chae Y. N. Jang I. K. Bae K. W. Ryu T. S. Yudintseva S. V. Yudintsev 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(1):73-77
This study was aimed at the synthesis, study of phase relations and characterization of the garnet ([Ca1.5GdCe0.5]VIII[ZrFe]VI[Fe
x
Al3−x
]IVO12, x = 0−2) intended as promising matrix for actinides (Pu) immobilization. The optimum temperatures of the fabrication of the
garnets ceramics are 1400 °C at x = 2 and 1500 °C at x = 0−1. The garnets lattice parameters and the content of Ce, as an imitator of Pu, increased with the content of iron. It
was suggested that the ability of the garnet for incorporation of Pu was closely related to the ionic radii of the elements
occupied the four-and six-coordinated sites of the structure. 相似文献
27.
To investigate the photoreactions of BrU in Z-DNA, the photoirradiation of 5'-d(C1G2C3G4BrU5G6C7G8)-3'/5'-d(C9mG10C11A12C13mG14C15G16)-3'(ODN 1-2) was investigated. In accord with previous observations, B-form ODN 1-2 with the 5'-GBrU sequence showed very weak photoreactivity. However, Z-form ODN 1-2 in 2 M NaCl underwent photoreaction to afford 5'-d(CGC)rGd(UGCG)-3' together with the formation of imidazolone (Iz) contained 5'-d(CIzCACmGCG)-3'. The results clearly indicate that structural changes caused by the B-Z transition dramatically increased the photoreactivity of ODN 1-2. Inspection of the molecular structure of Z-DNA suggests that there is unique four-base pi-stacks at the G4-BrU5-C11-mG10 in ODN 1-2. These results suggest that the intriguing possibility that the mG10 in a complementary strand located at the end of the four-base pi-stacks may act as an electron donor. To test the hypothesis of interstrand charge transfer from mG10 to BrU5 within the four-base pi-stacks in Z-DNA, ODN 1-3 samples in which the putative donor G10 residue was replaced with 8-methoxyguanine (moG) were prepared, since moG is known to trap cation radicals to yield Iz moieties in DNA. Photoirradiation of ODN 1-3 efficiently produced 5'-d(CGC)rGd(UGCG)-3' together with formation of 5'-d(CIzCACmGCG)-3'. These results clearly indicate that the interstrand charge transfer from mG10 to BrU5 initiates the photoreaction. In clear contrast, other replacements of G with moG did not enhance the photoreactivity. The present study revealed the presence of unique four-base pi-stacks in Z-DNA and photoirradition of BrU in Z-DNA causes efficient electron transfer from G within this cluster. 相似文献
28.
Fukuyama T Yamaura R Higashibeppu Y Okamura T Ryu I Kondo T Mitsudo TA 《Organic letters》2005,7(26):5781-5783
[reaction: see text] Catalytic [2 + 2 + 1 + 1] cocyclization reaction of an alkyne, an alkene, and two molecules of carbon monoxide, leading to functionalized hydroquinones, was studied. Using [Cp*RuCl2]2 as a catalyst, we found that a variety of electron-deficient alkenes, such as alpha,beta-unsaturated ketones, esters, amides, and nitriles, can be employed as an alkene coupling partner to give the corresponding hydroquinones. 相似文献
29.
Kim MK Oh S Lee JH Im H Ryu YM Oh E Lee J Lee E Sul D 《Experimental & molecular medicine》2004,36(5):396-410
In this study, we investigated the effects of PAHs and dioxin on mRNA and plasma protein expression using genomic and proteomic analysis for automobile emission inspectors and waste incineration workers. About 54 workers from automobile emission inspection offices, 31 workers from waste incinerating company and 84 unexposed healthy subjects were enrolled in this study. Urine and air samples were collected and analyzed by HPLC and GC/MS. Comet assays were carried out to evaluate any DNA damage in mononuclear and polynuclear cells. A significant difference in Olive tail moments in mononuclear cells was observed between exposed and control subjects (P < 0.0001). To examine the differences of the gene expression profile in automobile emission inspectors and waste incineration workers, radioactive complementary DNA microarrays were used to evaluate changes in the expression of 1,152 total genes. The gene expression profiles showed that 11 genes were up-regulated and 4 genes were down-regulated in waste incinerating workers as compared with controls. Plasma proteins were analyzed by 2-dimentional electrophoresis with pH 3-10 NL IPG Dry strip. The protein expression profiles showed that 8 proteins were up- regulated and 1 protein, haptoglobin, was down- regulated in automobile emission inspectors and waste incineration workers. Serum paraoxonase/ arylesterase was found only in the plasma of waste incineration workers. The expression of genes and proteins involved in oxidative stress were up-regulated in both automobile emission inspectors and waste incineration workers. Several proteins, such as transthyrethin, sarcolectin and haptoglobin, that were highly up- or down-regulated, could serve as biological monitoring markers for future study. 相似文献
30.
Kazunori Matsui Takayuki Kaneko Yasunori Yaginuma Masaru Ryu 《Journal of Sol-Gel Science and Technology》1997,9(3):273-277
A spin probe TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxy) was dissolved in a tetraethyl orthosilicate sol-gel reaction
system and measured by electron spin resonance spectroscopy at 295 K. The nitrogen hyperfine coupling constant was from 1.64–1.66
mT in the sol-gel solutions. The values were sensitive to the ethanol-to-water ratio of the solutions. The hyperfine coupling
constant in the xerogels was 1.70 mT, which was almost the same as that in water, indicating that the probe molecules were
trapped in silica pores with water adsorbed on the silica surfaces. The motion of TEMPOL in the xerogels was considerably
slower than in the sol-gel solutions. The local viscosity estimated was from 70–90 cP. The ESR spectra of TEMPOL were altered
during the sol-gel process, indicating that adsorbed water on the silicas surfaces has an important role for trapping organic
molecules in sol-gel glasses. 相似文献