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Madler S.,Laboratory of Organic Chemistry
Analytical and Bioanalytical Chemistry | Year: 2011

The 59th Conference on Mass Spectrometry and Allied Topics of the American Society for Mass Spectrometry (ASMS) was held on June 5, 2011 to June 9, 2011 at the Colorado Convention Center in Denver, Colorado. The conference offered short courses covering the basics of the most important mass spectrometric techniques. It covered several presentations focusing on the latest instrumental developments and applications of mass spectrometry (MS). Other presentations covered several areas such as systems biology/cellular pathways, energy, petroleum and biofuels, drug discovery and development, identification of posttranslational modifications, imaging of biological samples, plant proteomics, and drug metabolism and pharmacokinetics. Several sessions focused on methodological and instrumental developments for H/D exchange, biomolecular structure analysis, microscale and nanoscale separations, LC-MS detection of reactive metabolites, and imaging MS. Source

Merz T.,University of Zurich | Heck T.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Geueke B.,Eawag - Swiss Federal Institute of Aquatic Science and Technology | Mittl P.R.E.,University of Zurich | And 4 more authors.
Structure | Year: 2012

The β-aminopeptidase BapA from Sphingosinicella xenopeptidilytica belongs to the N-terminal nucleophile (Ntn) hydrolases of the DmpA-like family and has the unprecedented property of cleaving N-terminal β-amino acid residues from peptides. We determined the crystal structures of the native (αβ)4 heterooctamer and of the 153 kDa precursor homotetramer at a resolution of 1.45 and 1.8 Å, respectively. These structures together with mutational analyses strongly support mechanisms for autoproteolysis and catalysis that involve residues Ser250, Ser288, and Glu290. The autoproteolytic mechanism is different from the one so far described for Ntn hydrolases. The structures together with functional data also provide insight into the discriminating features of the active site cleft that determine substrate specificity. © 2012 Elsevier Ltd All rights reserved. Source

Moussouni S.,Mediterranean Agronomic Institute of Chania | Detsi A.,Laboratory of Organic Chemistry | Majdalani M.,Mediterranean Agronomic Institute of Chania | Makris D.P.,Technological Educational Institute of Larissa | Kefalas P.,Mediterranean Agronomic Institute of Chania
Tetrahedron Letters | Year: 2010

The potential of a crude peroxidase (POD) from onion solid waste as a biocatalyst for the synthesis of a naturally occurring aurone is described. The crude enzyme preparation effectively promotes the cyclization of 2′,3,4,4′,6′-pentahydroxy-chalcone (which is not a natural substrate of onion POD) into aureusidin. © 2010 Elsevier Ltd. All rights reserved. Source

Blokland M.H.,European Union | Van Tricht E.F.,European Union | Van Rossum H.J.,European Union | Sterk S.S.,European Union | And 2 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

For years it has been suspected that natural hormones are illegally used as growth promoters in cattle in the European Union. Unfortunately there is a lack of methods and criteria that can be used to detect the abuse of natural hormones and distinguish treated from non-treated animals. Pattern recognition of steroid profiles is a promising approach for tracing/detecting the abuse of natural hormones administered to cattle. Traditionally steroids are analysed in urine as free steroid after deconjugation of the glucuronide (and sulphate) conjugates. The disadvantage of this deconjugation is that valuable information about the steroid profile in the sample is lost. In this study we develop a method to analyse steroids at very low concentration levels (ng l~) for the free steroid, glucuronide and sulphate conjugates in urine samples. This method was used to determine concentrations of natural (pro)hormones in a large population (n = 620) of samples from male and female bovine animals and from bovine animals treated with testosterone-cypionate, estradiol-benzoate, dihydroepiandrosterone and pregnenolone. The data acquired were used to build a statistical model applying the multivariate technique 'Soft Independent Modeling of Class Analogy' (SIMCA). It is demonstrated that by using this model the results of the urine analysis can indicate which animal may have had illegal treatment with natural (pro)hormones. ©2012 Taylor & Francis. Source

Wauer T.,University of Oxford | Wauer T.,University of Cambridge | Gerlach H.,University of Oxford | Mantri S.,University of Oxford | And 5 more authors.
ACS Nano | Year: 2014

Previously, we reported the manual assembly of lipid-coated aqueous droplets in oil to form two-dimensional (2D) networks in which the droplets are connected through single lipid bilayers. Here we assemble lipid-coated droplets in robust, freestanding 3D geometries: for example, a 14-droplet pyramidal assembly. The networks are designed, and each droplet is placed in a designated position. When protein pores are inserted in the bilayers between specific constituent droplets, electrical and chemical communication pathways are generated. We further describe an improved means to construct 3D droplet networks with defined organizations by the manipulation of aqueous droplets containing encapsulated magnetic beads. The droplets are maneuvered in a magnetic field to form simple construction modules, which are then used to form larger 2D and 3D structures including a 10-droplet pyramid. A methodology to construct freestanding, functional 3D droplet networks is an important step toward the programmed and automated manufacture of synthetic minimal tissues. © 2013 American Chemical Society. Source

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