Active Site Mapping of Xylan-Deconstructing Enzymes with Arabinoxylan Oligosaccharides Produced by Automated Glycan Assembly

Xylan-degrading enzymes are crucial for the deconstruction of hemicellulosic biomass, making the hydrolysis products available for various industrial applications such as the production of biofuel. To determine the substrate specificities of these enzymes, we prepared a collection of complex xylan oligosaccharides by automated glycan assembly. Seven differentially protected building blocks provided the basis for the modular assembly of 2-substituted, 3-substituted, and 2-/3-substituted arabino- and glucuronoxylan oligosaccharides. Elongation of the xylan backbone relied on iterative additions of C4-fluorenylmethoxylcarbonyl (Fmoc) protected xylose building blocks to a linker-functionalized resin. Arabinofuranose and glucuronic acid residues have been selectively attached to the backbone using fully orthogonal 2-(methyl)naphthyl (Nap) and 2-(azidomethyl)benzoyl (Azmb) protecting groups at the C2 and C3 hydroxyls of the xylose building blocks. The arabinoxylan oligosaccharides are excellent tools to map the active site of glycosyl hydrolases involved in xylan deconstruction. The substrate specificities of several xylanases and arabinofuranosidases were determined by analyzing the digestion products after incubation of the oligosaccharides with glycosyl hydrolases.Fil: Senf, Deborah. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Ruprecht, Colin. Max Planck Institut für Kolloid und Grenzflächenforschung; AlemaniaFil: de Kruijff, Goswinus H. M.. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; Alemania. University Mainz. Institute of Institute of Organic Chemistry, Johannes Gutenberg; AlemaniaFil: Simonetti, Sebastián Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Química Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Química Rosario; Argentina. Max Planck Institut für Kolloid und Grenzflächenforschung; AlemaniaFil: Schuhmacher, Frank. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Seeberger, Peter H.. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; AlemaniaFil: Pfrengle, Fabian. Max Planck Institut für Kolloid und Grenzflächenforschung; Alemania. Freie Universität; Alemani

The genetic study of three population microisolates in South Tyrol (MICROS): study design and epidemiological perspectives

<p>Abstract</p> <p>Background</p> <p>There is increasing evidence of the important role that small, isolated populations could play in finding genes involved in the etiology of diseases. For historical and political reasons, South Tyrol, the northern most Italian region, includes several villages of small dimensions which remained isolated over the centuries.</p> <p>Methods</p> <p>The MICROS study is a population-based survey on three small, isolated villages, characterized by: old settlement; small number of founders; high endogamy rates; slow/null population expansion. During the stage-1 (2002/03) genealogical data, screening questionnaires, clinical measurements, blood and urine samples, and DNA were collected for 1175 adult volunteers. Stage-2, concerning trait diagnoses, linkage analysis and association studies, is ongoing. The selection of the traits is being driven by expert clinicians. Preliminary, descriptive statistics were obtained. Power simulations for finding linkage on a quantitative trait locus (QTL) were undertaken.</p> <p>Results</p> <p>Starting from participants, genealogies were reconstructed for 50,037 subjects, going back to the early 1600s. Within the last five generations, subjects were clustered in one pedigree of 7049 subjects plus 178 smaller pedigrees (3 to 85 subjects each). A significant probability of familial clustering was assessed for many traits, especially among the cardiovascular, neurological and respiratory traits. Simulations showed that the MICROS pedigree has a substantial power to detect a LOD score ≥ 3 when the QTL specific heritability is ≥ 20%.</p> <p>Conclusion</p> <p>The MICROS study is an extensive, ongoing, two-stage survey aimed at characterizing the genetic epidemiology of Mendelian and complex diseases. Our approach, involving different scientific disciplines, is an advantageous strategy to define and to study population isolates. The isolation of the Alpine populations, together with the extensive data collected so far, make the MICROS study a powerful resource for the study of diseases in many fields of medicine. Recent successes and simulation studies give us confidence that our pedigrees can be valuable both in finding new candidates loci and to confirm existing candidate genes.</p

Disputatio Ivridica, Desumta ex Titulo 4. de Condiĉtione causâ datâ causâ non secutâ, & seqq. usque ad finem libri XII. Pandectarum

quam, ... Sub Praesidio ... D. Johannis Jacobi Wissenbach, ... publicè ventilandam proponit Goswinvs Hasenhart, Steenv. Transis.Franeker, Univ., Univ.-Schr., 164

Electrochemical Preparation of Aryl Mom Ethers

In organic synthesis, methoxymethyl (MOM) ethers are frequently used as acid-labile protecting group [1] or leaving group in aryl cross-coupling reactions [2]. Their preparation commonly involves MOM chloride, a carcinogenic liquid with high vapour pressure which should be avoided as much as possible [3]. Therefore, we started to synthezise aryl MOM ethers without the use of MOM chloride by application of sustainable electrosynthetic methods [4]. Anodic decarboxylation of 2-aryloxy acetic acids under non-Kolbe conditions and trapping of the corresponding cation with methanol gives the desired MOM ethers (Figure 1). Indeed, this pathway is described for few aliphatic α-alkoxyacetic acids [5] and unsubstituted phenoxyacetic acid [6], but scope of this transformation to prepare substituted aryl MOM ethers has not been investigated so far. We now present our studies on the preparation of substituted aryl MOM ethers by anodic decarboxylation using an undivided cell setup. A wide range of substituents on the phenyl moiety is tolerated, giving access to valuable protected phenols [7]. References: [1] P. G. M. Wuts, T. W. Greene, Greene's Protective Groups in Organic Synthesis, John Wiley &amp; Sons, Inc, Hoboken, NJ, USA, 2006. [2] J. W. Dankwardt, Angew. Chem. Int. Ed. 2004, 43, 2428-2432. [3] Encyclopedia of Reagents for Organic Synthesis, John Wiley &amp; Sons, Ltd, Chichester, UK, 2001. [4] B. A. Frontana-Uribe, R. D. Little, J. G. Ibanez, A. Palma, R. Vasquez-Medrano, Green Chem. 2010, 12, 2099-2119. [5] H.-J. Schäfer in Topics in Current Chemistry, Vol. 152 (Ed.: E. Steckhan), Springer, Berlin Heidelberg, 1990. [6] S. I. Rosca, E.-M. Ungureanu, M.-G. Alexandru, U. P. B. Sci. Bull., Series B, 2007, 69, 3-10. [7] G. H. M. de Kruijff, S. R. Waldvogel, in preparation. Figure 1 <jats:p /

Biobased Epoxy Resin by Electrochemical Modification of Tall Oil Fatty Acids

A biobased epoxy resin was prepared from tall oil fatty acids (TOFAs), a byproduct of the pulping industry. As free carboxylic acids compromise resin stability, TOFA was subjected to non-Kolbe decarboxylation to give alkenes upon loss of CO2. Thereby, the degree of unsaturation is significantly increased. This electrosynthetic protocol using an undivided cell setup and inexpensive graphite electrodes in a galvanostatic operation mode was scaled to a 1.5 L reactor, making use of electric current as a green and waste-free reagent. Simple, cost-efficient epoxidation using oxone subsequently gives an epoxy resin of low viscosity. Curing with anhydrides yields thermoset materials. Dynamic mechanical analyses and tensile and flexural tests were conducted to determine the effect of different curing agents on the thermomechanical properties. For methyl tetrahydrophthalic anhydride (MTHPA) and methyl-5-norbornene-2,3-dicarboxylic anhydride (MNA), good mechanical properties were observed, whereas dodecenyl succinic anhydride (DDSA) resulted in a brittle material with low Tg

Metal-free electrochemical fluorodecarboxylation of aryloxyacetic acids to fluoromethyl aryl ethers

Electrochemical decarboxylation of aryloxyacetic acids followed by fluorination provides easy access to fluoromethyl aryl ethers.</p