395 research outputs found
Hardy-type inequalities for the generalized Mehler transform
We establish Hardy-type inequalities for the generalized Mehler transform on the real Hardy space H^p, 0 < p < 1
Paley\u27s inequality for the Jacobi expansions
金沢大学工学部金沢大学大学院自然科学研究科機能開発システムLet F(z) = Σ∞n=0 anzn be an analytic function in the unit disc satisfying sup 0<r<1 ∫2π0 |F(reiθ)| dθ < ∞. Then (Σ∞k=1 |a2k|2) 1/2 < ∞, which is familiar as Paley\u27s inequality. In this paper, an analogue of this inequality with respect to the Jacobi expansions is established
Identification of the basic amino acid residues on the PsbP protein involved in the electrostatic interaction with photosystem II
AbstractThe PsbP protein is an extrinsic subunit of photosystem II (PSII) that is essential for photoautotrophic growth in higher plants. Several crystal structures of PsbP have been reported, but the binding topology of PsbP in PSII has not yet been clarified. In this study, we report that the basic pocket of PsbP, which consists of conserved Arg48, Lys143, and Lys160, is important for the electrostatic interaction with the PSII complex. Our release-reconstitution experiment showed that the binding affinities of PsbP-R48A, -K143A, and -K160A mutated proteins to PSII were lower than that of PsbP-WT, and triple mutations of these residues greatly diminished the binding affinity to PSII. Even when maximum possible binding had occurred, the R48A, K143A, and K160A proteins showed a reduced ability to restore the rate of oxygen evolution at low chloride concentrations. Fourier transform infrared resonance (FTIR) difference spectroscopy results were consistent with the above finding, and suggested that these mutated proteins were not able to induce the normal conformational change around the Mn cluster during S1 to S2 transition. Finally, chemical cross-linking experiments suggested that the interaction between the N-terminus of PsbP with PsbE was inhibited by these mutations. These data suggest that the basic pocket of PsbP is important for proper association and interaction with PSII. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: Keys to Produce Clean Energy
A Substellar Companion to the Intermediate-Mass Giant 11 Com
We report the detection of a substellar companion orbiting the
intermediate-mass giant star 11 Com (G8 III). Precise Doppler measurements of
the star from Xinglong station and Okayama Astrophysical Observatory (OAO)
revealed Keplerian velocity variations with an orbital period of 326.03 +/-
0.32 days, a semiamplitude of 302.8 +/- 2.6 m/s, and an eccentricity of 0.231
+/- 0.005. Adopting a stellar mass of 2.7 +/- 0.3 M_solar, the minimum mass of
the companion is 19.4 +/- 1.5 M_Jup, well above the deuterium burning limit,
and the semimajor axis is 1.29 +/- 0.05 AU. This is the first result from the
joint planet search program between China and Japan aiming at revealing
statistics of substellar companions around intermediate-mass giants. 11 Com b
emerged from 300 targets of the planet search program at OAO. The current
detection rate of a brown dwarf candidate seems to be comparable to that around
solar-type stars within orbital separations of 3 AU.Comment: 19 pages, 4 figures, accepted by Ap
Atomic force microscopy sees nucleosome positioning and histone H1-induced compaction in reconstituted chromatin
AbstractWe addressed the question of how nuclear histones and DNA interact and form a nucleosome structure by applying atomic force microscopy to an in vitro reconstituted chromatin system. The molecular images obtained by atomic force microscopy demonstrated that oligonucleosomes reconstituted with purified core histones and DNA yielded a ‘beads on a string’ structure with each nucleosome trapping 158±27 bp DNA. When dinucleosomes were assembled on a DNA fragment containing two tandem repeats of the positioning sequence of the Xenopus 5S RNA gene, two nucleosomes were located around each positioning sequence. The spacing of the nucleosomes fluctuated in the absence of salt and the nucleosomes were stabilized around the range of the positioning signals in the presence of 50 mM NaCl. An addition of histone H1 to the system resulted in a tight compaction of the dinucleosomal structure
Ultra-high-purity iron is a novel and very compatible biomaterial
Metals and alloys are used widely in bone prosthetic materials, stents and dental tissue reconstructions. The most common materials are stainless steels and cobalt-chromium-nickel and titanium alloys. These alloys can be easily deformed but are hard to break. However, their affinity for cells and tissues is very low. In addition, they can sometimes provoke unexpected metal allergies. Iron is an abundant trace element essential for humans. However, excess amounts in particular of Fe2+ ions are toxic. We previously succeeded in obtaining 99.9996% ultra-high-purity iron (ABIKO iron). The chemical properties of ABIKO iron are completely different from that of conventional pure iron. For example, the reaction rate in hydrochloric acid is very slow and there is barely any corrosion. Here, we found that, in the absence of any type of coating, mammalian cells could easily attach to, and normally proliferate and differentiate on, ABIKO iron. On the other hand, cell densities and proliferation rate of the surfaces of plates made from Co–Cr–Mo or Ti–6Al–4V were significantly reduced. In addition, several stress and iron response genes, HSP70, SOD1, ATM and IRP2 did not change in the cells on ABIKO iron, while these genes were induced with exogenous application of FeSO4. Cells also secreted and fastened some organics on ABIKO iron. In vitro collagen binding assay showed that ABIKO iron binds higher amount of collagens. These findings highlight ABIKO iron as a novel biocompatible prosthetic material
Different growth and metastatic phenotypes associated with a cell-intrinsic change of Met in metastatic melanoma
A dynamic phenotypic change contributes to the metastatic progression and drug resistance in malignant melanoma. Nevertheless, mechanisms for a phenotypic change have remained to be addressed. Here, we show that Met receptor expression changes in a cell-autonomous manner and can distinguish phenotypical differences in growth, as well as in metastatic and drug-resistant characteristics. In metastatic melanoma, the cells are composed of Met-low and Met-high populations. Met-low populations have stem-like gene expression profiles, are resistant to chemotherapeutic agents, and have shown abundant angiogenesis and rapid tumor growth in subcutaneous inoculation. Met-high populations have a differentiated phenotype, are relatively resistant to B-RAF inhibitor, and are highly metastatic to the lungs. Met plays a definitive role in lung metastasis because the lung metastasis of Met-high cells requires Met, and treatment of mice with the Met-containing exosomes from Methigh cells facilitates lung metastasis by Met-low cells. Clonal cell fate analysis showed the hierarchical phenotypical changes from Met-low to Met-high populations. Met-low cells either showed self-renewal or changed into Met-high cells, whereas Met-high cells remained Met-high. Clonal transition from Met-low to Met-high cells accompanied changes in the gene expression profile, in tumor growth, and in metastasis that were similar to those in Met-high cells. These findings indicate that malignant melanoma has the ability to undergo phenotypic change by a cell-intrinsic/autonomous mechanism that can be characterized by Met expression
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