Elucidating a normal function of huntingtin by functional and microarray analysis of huntingtin-null mouse embryonic fibroblasts

Background

Multi-sensory integration is necessary for organisms to discriminate different environmental stimuli and thus determine behavior. Caenorhabditis elegans has 12 pairs of amphid sensory neurons, which are involved in generating behaviors such as thermotaxis toward cultivation temperature, and chemotaxis toward chemical stimuli. This arrangement of known sensory neurons and measurable behavioral output makes C. elegans suitable for addressing questions of multi-sensory integration in the nervous system. Previous studies have suggested that C. elegans can process different chemoattractants simultaneously. However, little is known about how these organisms can integrate information from stimuli of different modality, such as thermal and chemical stimuli.

Results

We studied the behavior of a population of C. elegans during simultaneous presentation of thermal and chemical stimuli. First, we examined thermotaxis within the radial temperature gradient produced by a feedback-controlled thermoregulator. Separately, we examined chemotaxis toward sodium chloride or isoamyl alcohol. Then, assays for simultaneous presentations of 15°C (colder temperature than 20°C room temperature) and chemoattractant were performed with 15°C-cultivated wild-type worms. Unlike the sum of behavioral indices for each separate behavior, simultaneous presentation resulted in a biased migration to cold regions in the first 10 min of the assay, and sodium chloride-regions in the last 40 min. However, when sodium chloride was replaced with isoamyl alcohol in the simultaneous presentation, the behavioral index was very similar to the sum of separate single presentation indices. We then recorded tracks of single worms and analyzed their behavior. For behavior toward sodium chloride, frequencies of forward and backward movements in simultaneous presentation were significantly different from those in single presentation. Also, migration toward 15°C in simultaneous presentation was faster than that in 15°C-single presentation.

Conclusion

We conclude that worms preferred temperature to chemoattractant at first, but preferred the chemoattractant sodium chloride thereafter. This preference was not seen for isoamyl alcohol presentation. We attribute this phase-dependent preference to the result of integration of thermosensory and chemosensory signals received by distinct sensory neurons.     

Direct observation of local distortion of a crystal lattice with picometer accuracy using atomic resolution neutron holography

We demonstrate that neutron holography permits us to extend the determination of atomic positions beyond nearest neighbors at least up to the fourth neighboring shell around cadmium probe atoms alloyed into a lead crystal. The accuracy achieved is sufficient to allow quantitative determination of displacements of atoms due to elastic distortions induced by impurity atoms. The atomic positions derived from the holographic data are in good agreement with those expected theoretically due to Friedel oscillations in this system. In addition, the atomic positions are in qualitative agreement with results obtained in an independent experiment studying the diffuse distortion scattering around Bragg peaks.     

Development of chemically modified glass surfaces for nucleic acid,protein and small molecule microarrays

Microarrays have become a widely used tool to investigate the living cell at different levels. DNA microarrays enable the expression analysis of thousand of genes simultaneously, while protein arrays investigate the properties and interactions of proteins with other proteins and with non-proteinaceous molecules. One crucial step in producing such microarrays is the permanent immobilization of samples on a solid surface. Our goal was to develop diverse linker systems capable of anchoring different biological samples, especially DNA and drug-like small molecules. We developed 6 different chemical surfaces having a 3-D-like linker system for biomolecule immobilization, and compared them to previously described immobilization strategies. The attachment chemistry utilizes the amino reactive properties of acrylic and epoxy functions. The capacity of the support was increased by creating a branching structure holding the reactive functions. The method of anchoring was investigated through a model reaction. From HPLC and mass spectrometry measurements we concluded that the covalent binding of DNA occurs through nucleobases. The tested systems offer the capability to permanently immobilize several biomolecular species in an array format.     

Measures of inset information on the open domain — I: Inset entropies and information functions of all degrees

This is one in a series of papers studying measures of information in the so-called mixed theory of information (i.e. considering the events as well as their probabilities) on the open domain (i.e. without empty sets and zero probabilities). In this paper we find all-recursive, 3-semisymmetric inset entropies on the open domain. We do this by solving the fundamental equation of inset information of degree () on the open domain.Dedicated to Professor János Aczél on his 60th birthday.     

Refractive index behavior of SiO2-P2O5 glass in optical fiber application

The refractive index of SiO₂-P₂O₅ glass prepared by a modified chemical vapor deposition method is measured using an interference microscope. It is found that the refractive index in bulk form increases linearly at 9.5×10^-4 (mol.%)^-1 as the P₂O₅ concentration increases. It is also found that quenching at extremely high speed reduces the refractive index over 2 mol.% P₂O₅. The wavelength dispersion of the refractive index dn/dλ is constant up to 5 mol.% P₂O₅ producing a refractive index difference of 5×10^-3 compared with fused silica. Consequently, this glass materials is thought to be suitable for wide band-width optical fiber applications.     

Eine neue papierchromatographische Methode zum Nachweis von Blei

Zusammenfassung Es wird über eine papierchromatographische Methode zum Nachweis von Bleiverunreinigungen in Schwermetallsalzen berichtet, die auf dem Unterschied zwischen der Löslichkeit des Bleisulfats und der übrigen Schwermetallsulfate beruht. Als Lösungsmittel wird das durch Rex u. Diller vorgeschlagene Gemisch Methanol-Schwefelsäure-Wasser verwendet. Nach der Chromatographie bleibt das Blei auf der Startlinie, während die übrigen Metalle mit R_f-Werten von 0,7–0,9 wandern. In den untersuchten Co²⁺-, Ni²⁺-, Cd-, Zn- und Cu-Salzen konnten im allgemeinen Bleiverunreinigungen von 30 g/g (=0,003%) nachgewiesen werden. Ni-, Cd- und Cu-Sulfate bleiben gleichfalls auf der Startlinie zurück, weshalb in diesen Salzen das Blei nach der beschriebenen Methode nicht nachgewiesen werden kann.Herrn Prof. Dr. A. Végh sind wir für die Unterstützung unserer Arbeit zu Dank verpflichtet.     

Ring Enlargement of Phospholenes to Phosphorin Derivatives Through Dichlorocarbene Adducts

Abstract

The ring enlargement of ready available phospholenes by dichlorocarbene addition to the double bond and subsequent opening of the cyclopropane ring is discussed. Adductcs of phospholene wih dichlorocarbene (2)can be synthetised under liquid-liquid phase transfer circumstances. The simplest bray to open the cyclopropane ring in the adducts is thermal transformation giving the two regioisomers of the appropriate dihydrophosphorin (3). Electrophilic reagents can also be used for -the opening of the cyclopropane ring. On heating with silver nitrate in water or in alcohols the adducts are transformed to the -two rcgioisomers of the hydroxy- or the alkoxy -tetrahydrophosphorins, respectively (4, Y=H, CH₃ C₂H₅) In the reaction of adducts with mercury acetate-acetic acid the corresponding acetoxy-derivatives (4, Y=CH₃CO) are formed. The Friedl Crofts reaction of the adducts with benzene iii the presence of aluminium trichloride yields diarylated product.     

DIHALOCARBENE ADDITION TO ARYLSUBSTTTUTED VINYL PHOSPHATES UNDER PHASE TRANSFER CATALYTIC CONDITIONS

Abstract

Dihalocarbene addition to aryl-substituted vinyl phosphates was carried out both in solid-liquid and in liquid-liquid two phase systems. The dihalocyclopropane adducts of vinyl phosphates could be obtained in better yield using dihalocarbenes generated by the latter method and no hydrolysis of the vinyl phosphate and of the adduct occurred under these circumstances. Eighteen new vinyl phosphate-dihalocarbene adducts were synthetized and characterized.     

Simple,Safe, Large Scale Synthesis of 5-Arylmethyl-2,2-dimethyl-1,3-dioxane-4,6-diones and 3-Arylpropanoic Acids

Reaction of aryl aldehydes with Meldrum's acid 2 in the presence of formic acid and triethylamine gives 5-arylmethyl Meldrum's acid derivatives 4 at room temperature, whereas at 80–100°C 3-arylpropanoic acids 5 are formed.