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1.
A full-length rabbit cDNA of cardiac adriamycin responsive protein (CARP) has been cloned. It shows high levels of identity at the amino acid sequence level (>86%) with the rat, mouse and human homologues. CARP mRNA levels are highly regulated in adriamycin-cardiomyopathy in rabbits. 相似文献
2.
Periodic and non-periodic responses of a periodically forced Hodgkin-Huxley oscillator 总被引:1,自引:0,他引:1
Membrane potential responses of a Hodgkin-Huxley oscillator to an externally-applied sinusoidal current were numerically calculated with relation to bifurcation parameters of the amplitude and the frequency of the stimulating current. The Hodgkin-Huxley oscillator, or the Hodgkin-Huxley axon in the state of self-sustained oscillation of action potentials, was realized by immersing the axon in calcium-deficient sea water. The forced oscillations were analysed by the stroboscopic plots and/or the Lorenz plots. The results show that the periodically forced Hodgkin-Huxley oscillator exhibits not only periodic motions (harmonic or sub-harmonic synchronization) but also non-periodic motions (quasi-periodic or chaotic oscillation), that the motions were determined by the amplitude and the frequency of the stimulating current, and that the characteristic motions obtained in the present study were in reasonable agreement with those of our previous results, found experimentally in squid giant axons. Also, two kinds of routes to the chaotic oscillations were found; successive period-doubling bifurcations and formation of the intermittently chaotic oscillation from sub-harmonic synchronization. 相似文献
3.
Cadaverine, a 5-carbon diamine, was identified as the cofactorof uricase activity previously found in soybean seedlings. Thesubstance purified from freeze dried hypocotyls was subjectedto liquid chromatography, mass spectrometry, 1H- and 13C-nuclearmagnetic resonance spectrometry for identification. The concentrationsof cadaverine in 3-day-old radicles and hypocotyls were 2.37mM and 5.09 mM, respectively. Other polyamine concentrationswere low. Biogenic polyamines (cadaverine, putrescine, spermidineand spermine) functioned as cofactors, whereas conjugated polyamines(tyramine and histamine) and amino acids had no effect. Theaddition of catalase to the assay system counteracted the effectof cadaverine. Peroxide at appropriate concentrations actedlike cadaverine with an identical Km value, suggesting thaturate degrading activity can be ascribed to the diamine oxidase-peroxidasesystem. (Received October 19, 1982; Accepted December 23, 1982) 相似文献
4.
Expression of gicerin in development, oncogenesis and regeneration of the chick kidney 总被引:1,自引:0,他引:1
5.
Characterization of estrogen receptor in estrogen-dependent transplantable rat pituitary tumor MtT/F84 总被引:1,自引:0,他引:1
Properties of nuclear and cytosolic estrogen receptors (ERs) were examined in a new transplantable rat pituitary tumor designated as MtT/F84, of which growth is stimulated by estrogen. The optimal incubation conditions of both nuclear and cytosolic exchange were found to be at 37 degrees C for 15 min and at 25 degrees C for 2 hr, respectively. Molybdate increased a specific binding of estradiol (E2) as determined by [3H]E2-binding assay. Sucrose density gradient analyses of crude cytosol revealed specific peaks of radioactivity in both 4-5S and 8-10S areas. However, only a single 5S peak was present in 0.4M KCl-extractable nuclear ER. Molybdate also enhanced the stability of cytosolic 8-10S receptor in density gradient sedimentation behavior. Scatchard plot analysis for nuclear ER yielded a single class of binding sites with a dissociation constant (Kd) of 0.317 nM and the maximum number of binding sites (NBSmax) of 25.4 fmol/mg protein. Saturation analysis of [3H]estrogen binding to cytosolic ER also yielded a straight line with a Kd of 0.146 nM and NBSmax of 58.5 fmol/mg protein. The effect of E2 administration on the intracellular distribution of ER was also examined. A marked disappearance in the ER binding in cytosol with a concomitant increase in binding in nuclear fraction was found after the administration of the unlabeled E2 in vivo, whereas the total number of ER did not change. Thus, it is concluded that properties of ER in the MtT/F84 were very similar to those in other target organs such as uterus and pituitary gland. 相似文献
6.
Instabilities and dynamic structure of the modified Hodgkin-Huxley equations (Adelman & FitzHugh, 1975) for sensitized axons were studied as a function of the sodium concentration in the external medium surrounding the axon. At the same time electrophysiological activities in squid giant axons were experimentally observed to confirm the results of the numerical calculation. It was found that the resting state of the axon was thermodynamically equivalent to a thermodynamic structure of an asymptotically stable equilibrium point. The state of spontaneous repetitive firing of action potentials corresponds to the dissipative structure with a stable limit cycle. The temporally coherent organization is realized through instability of the equilibrium point. 相似文献
7.
Ya‐Qian Zhang Yaosen Tian Yihan Xiao Lincoln J. Miara Yuichi Aihara Tomoyuki Tsujimura Tan Shi M. C. Scott Gerbrand Ceder 《Liver Transplantation》2020,10(27)
The interfacial instability between a thiophosphate solid electrolyte and oxide cathodes results in rapid capacity fade and has driven the need for cathode coatings. In this work, the stability, evolution, and performance of uncoated, Li2ZrO3‐coated, and Li3B11O18‐coated LiNi0.5Co0.2Mn0.3O2 cathodes are compared using first‐principles computations and electron microscopy characterization. Li3B11O18 is identified as a superior coating that exhibits excellent oxidation/chemical stability, leading to substantially improved performance over cells with Li2ZrO3‐coated or uncoated cathodes. The chemical and structural origin of the different performance is interpreted using different microscopy techniques which enable the direct observation of the phase decomposition of the Li2ZrO3 coating. It is observed that Li is already extracted from the Li2ZrO3 in the first charge, leading to the formation of ZrO2 nanocrystallites with loss of protection of the cathode. After 50 cycles separated (Co, Ni)‐sulfides and Mn‐sulfides can be observed within the Li2ZrO3‐coated material. This work illustrates the severity of the interfacial reactions between a thiophosphate electrolyte and oxide cathode and shows the importance of using coating materials that are absolutely stable at high voltage. 相似文献
8.
Interspecific pollen transfer (IPT) often leads to reproductive interference. Although character displacement of reproductive traits in plants is often considered a consequence of reproductive interference, few studies have tested whether intraspecific variation in floral morphology changes the intensity of reproductive interference among pollinator-sharing plants. We investigated whether intraspecific variation in pistil length changes the proportion of IPT (interspecific pollen transfer) in sympatric populations of Clerodendrum trichotomum and C. izuinsulare on the two islands. On Toshima Island, C. izuinsulare flowers with shorter pistils were significantly less likely to receive C. trichotomum pollen, and there was a slight tendency for longer pistiles of C. trichotomum flowers to receive less C. izuinsulare pollen, suggesting that IPT has caused character displacement in pistil length in these congeneric plants. In contrast, we did not detect any relationship between pistil length and the proportion of IPT for the two species on Niijima Island. The discrepancy between the islands may reflect differences in pollinator assemblages. 相似文献
9.
Natsuki Osaka Yu kanesaki Megumi Watanabe Satoru Watanabe Taku Chibazakura Hiraku Takada Hirofumi Yoshikawa Kei Asai 《Molecular microbiology》2020,113(6):1155-1169
In bacteria, guanosine (penta)tetra-phosphate ([p]ppGpp) is essential for controlling intracellular metabolism that is needed to adapt to environmental changes, such as amino acid starvation. The (p)ppGpp0 strain of Bacillus subtilis, which lacks (p)ppGpp synthetase, is unable to form colonies on minimal medium. Here, we found suppressor mutations in the (p)ppGpp0 strain, in the purine nucleotide biosynthesis genes, prs, purF and rpoB/C, which encode RNA polymerase core enzymes. In comparing our work with prior studies of ppGpp0 suppressors, we discovered that methionine addition masks the suppression on minimal medium, especially of rpoB/C mutations. Furthermore, methionine addition increases intracellular GTP in rpoB suppressor and this effect is decreased by inhibiting GTP biosynthesis, indicating that methionine addition activated GTP biosynthesis and inhibited growth under amino acid starvation conditions in (p)ppGpp0 backgrounds. Furthermore, we propose that the increase in intracellular GTP levels induced by methionine is due to methionine derivatives that increase the activity of the de novo GTP biosynthesis enzyme, GuaB. Our study sheds light on the potential relationship between GTP homeostasis and methionine metabolism, which may be the key to adapting to environmental changes. 相似文献
10.
Hitoshi Aihara Lavanya Katikala Robert W. Zeller Anna Di Gregorio Yutaka Nibu 《Marine biotechnology (New York, N.Y.)》2013,15(5):520-525
Chromatin immunoprecipitation (ChIP) assays allow the efficient characterization of the in vivo occupancy of genomic regions by DNA-binding proteins and thus facilitate the prediction of cis-regulatory sequences in silico and guide their validation in vivo. For these reasons, these assays and their permutations (e.g., ChIP-on-chip and ChIP-sequencing) are currently being extended to several non-mainstream model organisms, as the availability of specific antibodies increases. Here, we describe the development of a polyclonal antibody against the Brachyury protein of the marine invertebrate chordate Ciona intestinalis and provide a detailed ChIP protocol that should be easily adaptable to other marine organisms. 相似文献