Strong inhibitions: The inhibition of trehalases, enzymes which hydrolyze the disaccharide trehalose, is a target for novel antibiotic insecticides. The structures (see picture; C black, N blue, O red, S yellow) of a trehalase in complex with validoxylamine A (yellow) and 1‐thiatetrazolin (blue) reveal that the inhibitors tightly bind to the enzyme through hydrogen bonds.
A series of mono‐ to hexachlorinated BODIPY dyes have been prepared in good to excellent yields through the use of N‐chlorosuccinimide as an inexpensive halogenating reagent. This library of chlorinated dyes allowed analysis in detail, from the experimental and theoretical points of view, of the dependency of the photophysical and optical properties of the dyes on the number and positions of the chlorine substituents on their BODIPY cores. Quantum mechanical calculations predict the regioselectivity of the halogenation reaction and explain why some positions are less prone to chlorination. The new chlorinated BODIPYs exhibit enhanced laser action with respect to their non‐halogenated analogues, both in liquid solution and in the solid phase. In addition, chlorination is a facile and essentially costless protocol for overcoming important shortcomings exhibited by commercially available BODIPYs, which should favor their practical applications in optical and sensing fields.
Dedicated to Prof. Dr. Anronio G6mez-Sbnchez on the occasion of his 65th birthday.(5.1X.9 1) Diazo transfer from trifluoromethanesulfonyl azide (TfN,) to 2-amino-2-deoxy-glycoses constitutes a high-yielding, simple procedure for the preparation of partially protected or unprotected 2-azido-2-deoxy-aldoses. Thus, the o-allosamine derivative 2 gave 93% of 3, while diazo transfer to o-glucosamine, o-mannosamine, and o-galactosamine, followed by acetylation, yielded the azides 5, 7, and 9 in yields of 74-91, 65, and 70%, respectively.Introduction. -The 2-Azido-2-deoxy derivatives of mono-and disaccharides are frequently used intermediates in the synthesis of amino-deoxy oligosaccharides (see [ 11 for leading ref.). These azides have been prepared by azidonitration of glycals [2], by addition of halogeno azides to glycals [3], and from 1,6-anhydroglycoses either by opening of epoxides [4] or by substitution of 2-0-triflates [5]. The diastereoselectivity of the azidonitration and halogeno-azide addition depends on the configuration of the glycal. It is high for the lyxo-glycals, leading to mixtures of 2-azido-2-deoxy-galactose nitrates
Tunneling nanotubes (TnTs) are thin channels that temporally connect nearby cells allowing the cell-to-cell trafficking of biomolecules and organelles. The presence or absence of TnTs in human neoplasms and the mechanisms of TnT assembly remains largely unexplored. In this study, we have identified TnTs in tumor cells derived from squamous cell carcinomas (SCC) cultured under bi-dimensional and tri-dimensional conditions and also in human SCC tissues. Our study demonstrates that TnTs are not specific of epithelial or mesenchymal phenotypes and allow the trafficking of endosomal/lysosomal vesicles, mitochondria, and autophagosomes between both types of cells. We have identified focal adhesion kinase (FAK) as a key molecule required for TnT assembly via a mechanism involving the MMP-2 metalloprotease. We have also found that the FAK inhibitor PF-562271, which is currently in clinical development for cancer treatment, impairs TnT formation. Finally, FAK-deficient cells transfer lysosomes/autophagosomes to FAK-proficient cells via TnTs which may represent a novel mechanism to adapt to the stress elicited by impaired FAK signaling. Collectively, our results strongly suggest a link between FAK, MMP-2, and TnT, and unveil new vulnerabilities that can be exploited to efficiently eradicate cancer cells.
A one-step synthesis of octakis(3-azidopropyl)octasilsesquioxane from commercially available octakis(3-aminopropyl)octasilsesquioxane has been developed by a highly efficient diazo-transfer reaction under very mild conditions. Nonaflyl azide is shown to be a safer, cheaper and more efficient reagent for this transformation than the better known and generally used diazotransfer reagent triflyl azide. Octakis(3-azidopropyl)octasilsesquioxane is an excellent nanobulding block that can be readily octafunctionalized with a diversity of simple and highly functionalized terminal alkynes by copper(I)-catalyzed 1,3-dipolar azidealkyne cycloaddition under very mild conditions to provide new functional nanocages keeping a perfect 3-D cubic symmetry. The mildness, simplicity and efficiency of this approach have been demonstrated in the preparation of a glyco-POSS conjugate and a BODIPY-POSS cluster.
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