570 research outputs found
Anti-inflammatory sesquiterpenes from Curcuma zedoaria
This is a preprint of an article whose final and definitive form has been published in the NATURAL PRODUCT RESEARCH © 2006 copyright Taylor & Francis; NATURAL PRODUCT RESEARCH is available online at: http://www.informaworld.com/openurl?genre=article&issn=1478-6419&volume=20&issue=7&spage=680ArticleNATURAL PRODUCT RESEARCH. 20(7): 680-685 (2006)journal articl
Effects of Two Lactic Acid Bacteria Strains on the Fermentation and Aerobic Stability of Corn Silage
An efficient synthesis of procyanidins. Rare earth metal Lewis acid catalyzed equimolar condensation of catechin and epicatechin
ArticleTETRAHEDRON LETTERS. 48(33): 5891-5894 (2007)journal articl
Cyanamide mode of action during inhibition of onion (Allium cepa L.) root growth involves disturbances in cell division and cytoskeleton formation
Cyanamide is an allelochemical produced by hairy vetch (Vicia villosa Roth.). Its phyotoxic effect on plant growth was examined on roots of onion (Allium cepa L.) bulbs. Water solution of cyanamide (2–10 mM) restricted growth of onion roots in a dose-dependent manner. Treatment of onion roots with cyanamide resulted in a decrease in root growth rate accompanied by a decrease in accumulation of fresh and dry weight. The inhibitory effect of cyanamide was reversed by its removal from the environment, but full recovery was observed only for tissue treated with this chemical at low concentration (2–6 mM). Cytological observations of root tip cells suggest that disturbances in cell division may explain the strong cyanamide allelopathic activity. Moreover, in cyanamide-treated onion the following changes were detected: reduction of mitotic cells, inhibition of proliferation of meristematic cells and cell cycle, and modifications of cytoskeleton arrangement
The Initial-Final Mass Relation among White Dwarfs in Wide Binaries
We present the initial-final mass relation derived from 10 white dwarfs in
wide binaries that consist of a main sequence star and a white dwarf. The
temperature and gravity of each white dwarf was measured by fitting theoretical
model atmospheres to the observed spectrum using a fitting
algorithm. The cooling time and mass was obtained using theoretical cooling
tracks. The total age of each binary was estimated from the chromospheric
activity of its main sequence component to an uncertainty of about 0.17 dex in
log \textit{t} The difference between the total age and white dwarf cooling
time is taken as the main sequence lifetime of each white dwarf. The initial
mass of each white dwarf was then determined using stellar evolution tracks
with a corresponding metallicity derived from spectra of their main sequence
companions, thus yielding the initial-final mass relation. Most of the initial
masses of the white dwarf components are between 1 - 2 M. Our results
suggest a correlation between the metallicity of a white dwarf's progenitor and
the amount of post-main-sequence mass loss it experiences - at least among
progenitors with masses in the range of 1 - 2 M. A comparison of our
observations to theoretical models suggests that low mass stars preferentially
lose mass on the red giant branch.Comment: 28 pages, 8 figures, accepted for publication in Ap
Structural insights into the HBV receptor and bile acid transporter NTCP
B型肝炎ウイルスの受容体“胆汁酸輸送体”の立体構造を解明. 京都大学プレスリリース. 2022-05-18.Roughly 250 million people are infected with hepatitis B virus (HBV) worldwide, and perhaps 15 million also carry the satellite virus HDV, which confers even greater risk of severe liver disease. Almost ten years ago the HBV receptor was identified as NTCP (sodium taurocholate co-transporting polypeptide), which interacts directly with the first 48 amino acid residues of the N-myristoylated N-terminal preS1 domain of the viral large (L) protein. Despite the pressing need for therapeutic agents to counter HBV, the structure of NTCP remains unsolved. This 349-residue protein is closely related to human apical sodium-dependent bile acid transporter (ASBT), another member of the solute carrier family SLC10. Crystal structures have been reported of similar bile acid transporters from bacteria, and these models with ten transmembrane helices are believed to resemble strongly both NTCP and ASBT. Using cryo-electron microscopy we have solved the structure of NTCP bound to an antibody, clearly showing the transporter has no equivalent to the first transmembrane helix of other SLC10 models, leaving the N-terminus exposed on the extracellular face. Comparison of the different structures indicates a common mechanism of bile acid transport, but the NTCP structure also displays a pocket formed by residues known to interact with preS1, presenting new and enticing opportunities for structure-based drug design
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