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排序方式: 共有803条查询结果,搜索用时 15 毫秒
1.
myc oncogenes: activation and amplification 总被引:12,自引:0,他引:12
2.
Cytosolic and mitochondrial isozymes of aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase [EC 2.6.1.1] ) were purified to homogeneity from rabbit liver. The rabbit liver isozymes were closely similar to the corresponding isozymes from other sources, including human heart, pig heart, chicken heart, and rat liver, in their molecular weights, absorption spectra, amino acid compositions, isoelectric points, and Michaelis constants for the substrates. The NH2-terminal amino acid sequences of rabbit liver isozymes were identified up to 30 residues, and showed some differences from those of the corresponding isozymes obtained from other animals so far studied. 相似文献
3.
We examined the applicability of radiotelemetry to studies of acorn dispersal byApodemus mice and compared its efficiency with the of this spool-and-line method. Installation of a transmitter (2.2 g) onto acorns
did not interfere with the transporting and feeding behavior of the mice. We were able to detect all transmitter-installed
acorns and follow the daily changes in the sites in which they were hoarded, while we missed 59% of the spool-tied acorns
due to mice breaking the threads. Mice carried transmitter-installed acorns farther than spool-tied ones. The radiotelemetry
method is superior to the spool-and-line method and useful for the study of hoarding behavior in rodents. 相似文献
4.
Mayumi Nishikata Aki Nakai Hitomi Fushida Keishiro Miyake Takaichi Arita Ken Iseki Katsumi Miyazaki Akikazu Nomura 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1993,612(2)
A method is described for the simultaneous determination of (+)- and (−)-homochlorcyclizine (HCZ) in human urine by high-performance liquid chromatography on a chiral stationary phase of ovomucoid-bonded silica. The pH of the buffer and organic modifier in the mobile phase markedly affected the chromatographic separation. A mobile phase of methanol—0.02 M acetate buffer (pH 4.7) (25:75, v/v) at a flow-rate of 1.0 ml/min was used for the urine assays. The ultraviolet absorption was monitored at 240 nm, and diphenhydramine was employed as the internal standard for the quantitation. (+)-HCZ, (−)-HCZ and the internal standard were eluted at retention times of 15, 25 and 8 min, respectively. The limit of determination for HCZ enantiomers was ca. 50 ng/ml of urine. One of the metabolites in human urine, which was a quaternary ammonium-linked glucuronide, could also be determined in a manner similar to unchanged HCZ after β-glucuronidase hydrolysis. A pharmacokinetic study was conducted with three healthy volunteers, who each received a single oral dose of racemic HCZ (20 mg). Distinct differences were found between the two enantiomers, particularly in the metabolic process, that is, the urinary excretion as (−)-HCZ-glucuronide within 48 h was ca. four times higher than that of the (+)-isomer. This method should be very useful for enantioselective pharmacokinetic studies of HCZ. 相似文献
5.
P J Hurlin C Quéva P J Koskinen E Steingrímsson D E Ayer N G Copeland N A Jenkins R N Eisenman 《The EMBO journal》1995,14(22):5646-5659
6.
The oxidase reaction of lipoamide dehydrogenase with NADH generates superoxide radicals and hydrogen peroxide under aerobic conditions. ESR spin trapping using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was applied to characterize the oxygen radical species generated by lipoamide dehydrogenase and the mechanism of their generation. During the oxidase reaction of lipoamide dehydrogenase, DMPO-OOH and DMPO-OH signals were observed. The DMPO-OOH signal disappeared on addition of superoxide dismutase. These results demonstrate that the DMPO-OOH adduct was produced from the superoxide radical generated by lipoamide dehydrogenase. In the presence of dimethyl sulfoxide, a DMPO-CH3 signal appeared at the expense of the DMPO-OH signal, indicating that the DMPO-OH adduct was produced directly from the hydroxyl radical rather than by decomposition of the DMPO-OOH adduct. The DMPO-OH signal decreased on addition of superoxide dismutase, catalase, or diethylenetriaminepentaacetic acid, indicating that the hydroxyl radical was generated via the metal-catalyzed Haber-Weiss reaction from the superoxide radical and hydrogen peroxide. Addition of ferritin to the NADH-lipoamide dehydrogenase system resulted in a decrease of the DMPO-OOH signal, indicating that the superoxide radical interacted with ferritin iron. 相似文献
7.
Electron transfer between horse heart and Candida krusei cytochromes c in the free and phosvitin-bound states was examined by difference spectrum and stopped-flow methods. The difference spectra in the wavelength range of 540–560 nm demonstrated that electrons are exchangeable between the cytochromes c of the two species. The equilibrium constants of the electron transfer reaction for the free and phosvitin-bound forms, estimated from these difference spectra, were close to unity at 20°C in 20 mM Tris-HCl buffer (pH 7.4). The electron transfer rate for free cytochrome c was (2–3) · 104 M?1 · s?1 under the same conditions. The transfer rate for the bound form increased with increase in the binding ratio at ratios below half the maximum, and was almost constant at higher ratios up to the maximum. The maximum electron exchange rate was about 2 · 106 M?1 · s?1, which is 60–70 times that for the free form at a given concentration of cytochrome c. The activation energy of the reaction for the bound cytochrome c was equal to that for the free form, being about 10 kcal/mol. The dependence of the exchange rate on temperature, cytochrome c concentration and solvent viscosity suggests that enhancement of the electron transfer rate between cytochromes c on binding to phosvitin is due to increase in the collision frequency between cytochromes c concentrated on the phosvitin molecule. 相似文献
8.
Activation of peroxisome proliferator-activated receptor-alpha stimulates both differentiation and fatty acid oxidation in adipocytes 总被引:1,自引:0,他引:1
Goto T Lee JY Teraminami A Kim YI Hirai S Uemura T Inoue H Takahashi N Kawada T 《Journal of lipid research》2011,52(5):873-884
Peroxisome proliferator-activated receptor-α (PPARα) is a dietary lipid sensor, whose activation results in hypolipidemic effects. In this study, we investigated whether PPARα activation affects energy metabolism in white adipose tissue (WAT). Activation of PPARα by its agonist (bezafibrate) markedly reduced adiposity in KK mice fed a high-fat diet. In 3T3-L1 adipocytes, addition of GW7647, a highly specific PPARα agonist, during adipocyte differentiation enhanced glycerol-3-phosphate dehydrogenase activity, insulin-stimulated glucose uptake, and adipogenic gene expression. However, triglyceride accumulation was not increased by PPARα activation. PPARα activation induced expression of target genes involved in FA oxidation and stimulated FA oxidation. In WAT of KK mice treated with bezafibrate, both adipogenic and FA oxidation-related genes were significantly upregulated. These changes in mRNA expression were not observed in PPARα-deficient mice. Bezafibrate treatment enhanced FA oxidation in isolated adipocytes, suppressing adipocyte hypertrophy. Chromatin immunoprecipitation (ChIP) assay revealed that PPARα was recruited to promoter regions of both adipogenic and FA oxidation-related genes in the presence of GW7647 in 3T3-L1 adipocytes. These findings indicate that the activation of PPARα affects energy metabolism in adipocytes, and PPARα activation in WAT may contribute to the clinical effects of fibrate drugs. 相似文献
9.
10.
Zolzaya Tumurgan Haruhiko Kanasaki Tuvshintugs Tumurbaatar Aki Oride Hiroe Okada Satoru Kyo 《Biochemistry and Biophysics Reports》2020
Hypothalamic kisspeptin, encoded by the Kiss-1 gene, governs the hypothalamic-pituitary-gonadal axis by directly regulating the release of gonadotropin-releasing hormone. In this study, we examined the roles of activin, inhibin, and follistatin in the regulation of Kiss-1 gene expression using primary cultures of fetal rat neuronal cells, which express the Kiss-1 gene and kisspeptin. Stimulation with activin significantly increased Kiss-1 gene expression in these cultures by 2.02 ± 0.39-fold. In contrast, a significant decrease in Kiss-1 gene expression was observed with inhibin A and follistatin treatment. Inhibin B did not modulate Kiss-1 gene expression. Activin, inhibin, and follistatin were also expressed in fetal rat brain cultures and their expression was controlled by estradiol (E2). The inhibin α, βA, and βB subunits were upregulated by E2. Similarly, follistatin gene expression was significantly increased by E2 in these cells. Our results suggest the possibility that activin, inhibin, and follistatin expressed in the brain participate in the E2-induced feedback control of the hypothalamic-pituitary-gonadal axis. 相似文献