RESUMEN
Metabolic distribution of fatty acid to organelles is an essential biological process for energy homeostasis as well as for the maintenance of membrane integrity, and the metabolic pathways are strictly regulated in response to environmental stimuli. Herein, we report a fluorescent fatty acid probe, which bears an azapyrene dye that changes its absorption and emission features depending on the microenvironment polarity of the organelle into which it is transported. Owing to the environmental sensitivity of this dye, the distribution of the metabolically incorporated probe in non-polar lipid droplets, medium-polarity membranes, and the polar aqueous regions, can be visualized in different colors. Based on density scatter plots of the fluorophore, we demonstrate that the degradation of triacylglycerols in lipid droplets occurs predominantly via lipolysis rather than lipophagy in nutrition-starved hepatocytes. This tool can thus be expected to significantly advance our understanding of the lipid metabolism in living organisms.
Asunto(s)
Ácidos Grasos , Colorantes Fluorescentes , Ácidos Grasos/metabolismo , Colorantes Fluorescentes/metabolismo , Gotas Lipídicas/metabolismo , Metabolismo de los Lípidos/fisiología , Lipólisis/fisiologíaRESUMEN
The synthesis and photophysical properties of a soluble amide-embedded coronene is reported. The key step in this synthesis is the twofold C-H activation of diazaperylene by a rhodium(III)Cp* catalyst. This unprecedented structural motif shows intense fluorescence in the near infrared region with a small Stokes shift and a distinct vibronic structure, which exhibits a slight extent of negative solvatochromism. Comparison of this compound with some relevant compounds revealed the importance of the amide incorporation in the peripheral concave region including an angular position to retain high aromaticity reflecting that of parent coronene. Treatment of this compound with Lewis acid B(C6 F5 )3 formed a bis-adduct, which exhibited enhanced aromaticity as a consequence of the increased double bond character of the amide C-N bonds.
RESUMEN
Bright fluorescent molecules with long fluorescence lifetimes are important for the development of lifetime-based fluorescence imaging techniques. Herein, a molecular design is described for simultaneously attaining long fluorescence lifetime (τ) and high brightness (ΦF ×É) in a system that features macrocyclic dimerization of fluorescent π-conjugated skeletons with flexible linkers. An alkylene-linked macrocyclic dimer of bis(thienylethynyl)anthracene was found to show excimer emission with a long fluorescence lifetime (τ≈19â ns) in solution, while maintaining high brightness. A comparison with various relevant derivatives revealed that the macrocyclic structure and the length of the alkylene chains play crucial roles in attaining these properties. Inâ vitro time-gated imaging experiments were conducted as a proof-of-principle for the superiority of this macrocyclic fluorophore relative to the commercial fluorescent dye Alexa Fluorâ 488.
RESUMEN
We disclose the development of a ratiometric fluorescent probe based on a benzophosphole P-oxide and its application for the detection of intracellular Na(+) ions. Excitation by visible light induced red emission from this probe in water, which was subjected to a hypsochromic shift upon complexation with Na(+). Based on this change, a ratiometric analysis enabled us to visualise changes in the Na(+) concentration in living mammalian cells.
Asunto(s)
Óxidos P-Cíclicos/química , Colorantes Fluorescentes/química , Óxidos/química , Sodio/análisis , Óxidos P-Cíclicos/síntesis química , Colorantes Fluorescentes/síntesis química , Células HeLa , Humanos , Iones/análisis , Estructura Molecular , Óxidos/síntesis químicaRESUMEN
The Higashi-Ohgishima viaduct of Metropolitan Expressway. Bay-shore Route (4th phase), is a 9-span continuous prestressed concrete box-girder bridge using base isolator. In order to improve seismic resistance, a reaction distribution method using rubber bearing supports was adopted for the bridge. In addition, seismic design using menshin technology was carried out so that the piers, bearing supports and main girders would withstand an earthquake of the magnitude of the Great Earthquake of 1923. For the bearing, the LRB bearing having energy dissipating capability was adopted, and its dynamic characteristics were verified by approving test for dynamic load and elasto-plastic dynamic analysis. Vibration test were also perfomed on the bridge itself during construction to confirm the propriety of the design.(AU)