Development of molecular imaging tools to investigate protein functions by chemical probe design

Molecular imaging technologies, which enable the visualization of the behaviors or functions of biomolecules in living systems, have received considerable attention from life scientists. Novel imaging technologies that overcome the limitations of current imaging techniques are desired. In this review, two independent technologies that were recently developed by the authors are described. The first technology is for smart (19)F magnetic resonance imaging (MRI) probes that were developed for in vivo applications. These probes were developed by exploiting paramagnetic relaxation enhancement in order to detect hydrolase activity. With respect to cellular applications, gene expression in cells was visualized using one of the (19)F MRI probes. It was confirmed that this probe design principle is effective for various hydrolases, and broad applications are expected. The second technology is for practical protein labeling. This labeling method is based on a mutant β-lactamase and its specific labeling probes. Since the probe is fluorescence resonance energy transfer (FRET)-based, this labeling method achieves both specific and fluorogenic labeling of target proteins. In addition, derivatization of the probe enabled the labeling of intracellular proteins and the modification of various functional molecules.     

Approximate solution for kinetic differential equations

Summary In the present work we show the analysis of an approximate solution for the coupled kinetic differential equations of a defect involving processes of untrapping, retrapping and recombination annihilation, using the Poincaré-Dulac theorem. The authors of this paper have agreed to not receive the proofs for correction.     

Decentralized robust control for a class of uncertain large-scale interconnected nonlinear dynamical systems

The problem of the decentralized robust control for a class of large-scale interconnected nonlinear dynamical systems with input interconnection and external interconnection perturbations is considered. Based on the stabilizability of each nominal isolated subsystem (i.e., the isolated subsystem in the absence of interconnection perturbations), a class of decentralized local state feedback controllers is proposed, and some sufficient conditions are derived by making use of the Lyapunov stability criterion such that uncertain large-scale interconnected systems can be stabilized asymptotically by these decentralized state feedback controllers. For large-scale systems with only input interconnection perturbations, such decentralized controllers become a class of decentralized stabilizing state feedback controllers. That is, the decentralized stability of such large-scale systems can be guaranteed always by using the decentralized state feedback controllers proposed in the paper. Finally, a numerical example is given to demonstrate the validity of the results.     

New sesquiterpene lactones from water extract of the root of Lindera strychnifolia with cytotoxicity against the human small cell lung cancer cell, SBC-3

In the present study, new sesquiterpene lactones (1) and (2) were isolated from the EtOAc soluble fraction of the water extract of Linderae Radix through bioassay-guided fractionation and isolation methods. The structure of these compounds was elucidated by spectroscopic analysis of their 2D NMR spectra, including COSY, HMBC, and HMQC techniques. Two isolates showed significant cytotoxicity against the human small cell lung cancer cell SBC-3, and lesser cytotoxicity against mouse fibroblast cell 3T3-L1.     

Effect of Alkynyl Group on Reactivity in Photoaffinity Labeling with 2-Thienyl-Substituted α-Ketoamide

Minimalist photo-reactive probes, which consist of a photo-reactive group and a tag for detection of target proteins, are useful tools in chemical biology. Although several diazirine-based and aryl azide-based minimalist probes are available, no keto-based minimalist probe has yet been reported. Here we describe minimalist probes based on a 2-thienyl-substituted α-ketoamide bearing an alkyne group on the thiophene ring. The 3-alkyne probe showed the highest photo-affinity labeling efficiency.     

Multiple determinations in the micro Dumas nitrogen method

Summary A multiple analysis method for the Dumas nitrogen determination has been described. The furnace is provided with eight combustion tubes arranged in a circle around the axis of the furnace. An improved nozzle-type nitrometer, without ground joints, has been designed. The multiple determinations are simultaneously carried out as in usual method, permitting thirty two analyses in a 7-hour working day. The standard deviation-error of estimate from 88 analyses in routine work is ±0.12% N.

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Zusammenfassung Ein Verfahren zur gleichzeitigen Durchführung mehrerer Stickstoffbestimmungen nachDumas wurde beschrieben. Der Verbrennungsofen kann acht Verbrennungsrohre in gleichmäßiger Entfernung von seiner Längsachse aufnehmen. Ein verbessertes Düsenazotometer ohne Schliffverbindungen wurde konstruiert. Die Analysen werden gleichzeitig in der üblichen Art durchgeführt, so daß im 7stündigen Arbeitstag 32 Bestimmungen möglich sind. Die mittlere Abweichung von 88 Analysen im Routinebetrieb betrug ± 0,12% N.

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Résumé On a décrit une méthode d'analyse multiple pour le dosage de l'azote selonDumas. Le four est muni de huit tubes á combustion disposés suivant un cercle autour de l'axe du four. On a construit un nitromètre perfectionné de type à étranglement, sans joints rodés. On effectue simultanément les dosages multiples comme dans la méthode habituelle, ce qui permet de réaliser trente deux analyses en une journée de travail de 7 heures. L'écart type calculé à partir de 88 analyses dans un travail en série est de ±0,12% N.

     

Interaction of wheat germ agglutinin with an N-acetylglucosamine-carrying telomer brush accumulated on a colloidal gold monolayer

A disulfide-carrying telomer with many pendent N-acetylglucosamine (GlcNAc) residues (Cys-PMHGlcNAc) was obtained by photo-polymerization of 1-(6'-methacryloylaminohexyl)-2-N-acetoamido-2-deoxy d-glucopyranoside) (MHGlcNAc) using a benzyl N,N-diethyldithiocarbamoyl (BDC) derivative that shows abilities of initiation, transfer, and termination (iniferter). The disulfide-carrying telomer was accumulated on a monolayer of colloidal Au on a glass substrate, and the interaction of wheat germ agglutinin (WGA) with GlcNAc residue at the polymer brush-solution interface was examined by using the localized surface plasmon resonance (LSPR) technique. For comparison, an amphiphile carrying many pendent GlcNAc residues was also prepared with MHGlcNAc and a lipophilic radical initiator and was incorporated in a phospholipid liposome to examine interaction of the GlcNAc residue with WGA on the liposome surface using turbidity measurements. Both the colloidal gold optical device and the liposome showed a concentration-dependent specific binding of WGA, and the GlcNAc-carrying liposome had a detection limit of 100 nM for WGA, whereas that of the colloidal gold device was 10nM. The sugar-carrying telomer-coated device examined here is not only useful as a simple biosensor chip but is also expected to expand our knowledge of bio-related phenomena at the liquid-telomer brush interfaces on a colloidal Au.