S‐Adenosyl‐Methionine‐Dependent Methyltransferases: Highly Versatile Enzymes in Biocatalysis,Biosynthesis and Other Biotechnological Applications

S‐adenosyl methionine (SAM) is a universal biological cofactor that is found in all branches of life where it plays a critical role in the transfer of methyl groups to various biomolecules, including DNA, proteins and small‐molecule secondary metabolites. The methylation process thus has important implications in various disease processes and applications in industrial chemical processing. This methyl transfer is catalysed by SAM‐dependent methyltransferases (MTases), which are by far the largest groups of SAM‐dependent enzymes. A significant amount is now known regarding the structural biology and enzymology of these enzymes, and, consequently, there is now significant scope for the development of new MTases and SAM analogues for applications from biomolecular imaging to biocatalytic industrial processes. This review will focus on current efforts in the manipulation of class I and V SAM‐dependent MTases and the use of synthetic SAM analogues, which together offer the best prospects for rational redesign towards biotechnological applications. Firstly, metabolic engineering of organisms incorporating small‐molecule MTases is discussed; this can be applied in a variety of areas from the industrial bioprocessing of flavourants and antibiotics to frontier research in biofuel production and bioremediation. Secondly, the application of MTases in combination with SAM analogues is reviewed; this allows the tagging of proteins and oligonucleotides with moieties other than the methyl group. Such tagging allows the isolation of the tagged biomolecule and aids its visualisation by a range of analytical methods. The review then summarises the potential advantages of MTase‐mediated chemistry and offers some future perspectives on downstream applications.     

Surface functionalization of polymer networks. Sulfonation of the internal surface of macroporous styrene-divinylbenzene copolymers

Surface functionalization of porous polymer networks was investigated using the sulfonation of macroporous styrene-divinylbenzene (S-DVB) copolymers as model reaction. Reaction conditions for the surface sulfonation were studied. Sulfonation with sulfuric acid in the presence of nitromethane was found to be a suitable method. Models and ideas of network structure are developed in order to estimate surface capacities and to show that surface-sulfonated networks were obtained.     

Niederdruckumkehrosmose mit modifizierten polyacrylnitril-ultrafiltrationsmembranen

The chemical modification of polyacrylonitrile ultrafiltration (PAN-UF) membranes by hydroxylamine yields low-pressure reverse-osmosis (LP-RO) membranes containing amidoxime and hydroxamic acid groups besides nitrile groups. These membranes are positively charged at pH values of 4.0 to 6.5. The water permeability of the membranes decreases from 400 L h^?1 m^?2 to 15 L h^?1 m^?2 (p = 0.3 MPa) by this modification. A comprehensive characterization was carried out by retention curves, IR and NMR spectra, Hg porosimetry, measurement of membrane potentials and separation performance regarding different metal salts. Due to the Donnan exclusion these membranes have a retention of 88% at a filtrate flux of 8 L h^?1 m^?2(p = 0.3 MPa) regarding bivalent metal ions like Ca²⁺ and Mg²⁺ which cause the water hardness. Regarding heavy metal ions like Cu²⁺ and In³⁺ much higher filtrate fluxes from 90 to 100 L h^?1 m^?2 (p = 0.3 MPa) are possible. In water medium without any heavy metal ions the amidoxime and hydroxamic acid groups are hydrolysed to carboxylic acid groups which are able to reject multivalentanions. By this the water softening ability remains.     

Systematisierung des Nutzens von ERP-Systemen in der Fertigungsindustrie

This paper classifies and explores the benefits of Enterprise Resource Planning (ERP) systems using the individual manufacturing facility as the level of analysis. We focused on German companies using SAP R/3. Two successful cases are described in detail. The cases revealed that remarkable benefits have been realized in the following categories: ?Process efficiency (business processes)”, ?Market efficiency (market and customer orientation)”, ?Resource efficiency (productivity and profitability)”, and ?Delegation efficiency (gathering of information)”. Data standardization and integration explain many of these benefits. However, the users complain about higher workloads as a result of the complexity and required data structures of these systems. Therefore, they show lower acceptance for the new system.     

DInSAR investigation in the Pärvie end-glacial fault region,Lapland, Sweden

Northern Fennoscandia bears witness to the Pleistocene glaciation in the form of a series of large faults that have been shown to have ruptured immediately after the retreat of the ice sheet, about 9500 years ago. The largest one, known as the Pärvie fault, consists of a 155 km long linear series of fault scarps forming north–northeast-trending, that stretch west of Kiruna, Lapland. End-glacial intra-plate faults of this extent are very rare in the continental crust and the Pärvie system represents one of the major fault zone structures of this type in the world. Seismological evidence shows that there is still noticeable seismic activity, roughly one event of magnitude 2 per year that can be attributed to the fault. Nevertheless assessing its state of activity is a difficult task due to the extent and remoteness of the area. This study is aimed at the determination of crustal motion around the Pärvie fault zone using the differential inter-ferometric synthetic aperture radar (DInSAR) technique, based on images acquired with the European Space Agency (ESA) satellites European Remote Sensing (ERS) 1, ERS-2, and the Environmental Satellite (ENVISAT). We present results achieved in terms of deformation of the crystalline bedrock along different sectors of the fault where high levels of coherence were obtained, even from image pairs several years apart. This finding does not exclude deformation in other segments, as observing conditions are not always as favourable in terms of data availability.     

Authoring vs. Configuring Affective Agents for Interactive Storytelling

Autonomous characters in interactive storytelling can be supported by using affective agent architectures. The configuration of most current tools for controlling agents is, however, implementation specific and not tailored to the needs of authors. Based on literature review, a questionnaire evaluation of authors’ preferences for character creation, and a case study of an author’s conceptualization of this process, we investigate the different methods of configuration available in current agent architectures, reviewing discrepancies and matches. Given these relations, promising approaches to configuration are identified, based on initial inner states, “global” parameters of characters, libraries of stock characters, and selections of backstory experiences.     

Immobilization of enzymes onto modified polyacrylonitrile membranes: Application of the acyl azide method

Chemical reactions toward acyl azide activated polyacrylonitrile (PAN) and conditions for membrane surface modifications are described. Ultrafiltration (UF) membranes were prepared from PAN homopolymer and copolymer with methyl acrylate. Besides hydrazide formation and nitrosation, a new method to introduce acyl azide groups into carboxyl modified PAN, using azido transfer with diphenyl phosphoryl azide, was developed. Chemical conversions were characterized, especially with Fourier transform infrared spectroscopy. The heterogeneous modifications are not chemically selective due to side reactions and/or incomplete conversion. The pore structure is altered predominately via modified polymer swelling causing changed UF fluxes and selectivities. However, for the modification via PAN reaction with hydroxyl amine, acid hydrolysis, and azido transfer, the initial membrane separations performance is qualitatively preserved. Using the acyl azide ḿethod, amylo-glucosidase (AG) (EC 3.2.1.3) was immobilized onto the modified PAN UF membranes, enabling hydrolysis of starch or maltose to glucose. Enzyme activity was assayed depending on previous chemical modification (azide content) and immobilization (pH) conditions as well as hydrolysis parameters (substrate, conversion during diffusion or UF). The best results (up to 600 mU/cm² at 40°C and pH 5.0) were obtained after modification of PAN membranes via carboxyl creation and azido transfer. AG convalently bound to PAN is not influenced much in its catalytic properties (K_m = 3.48 and 3.1 mmol/L for free and bound AG, respectively, with maltose at 40°C and pH 5.0). Under UF conditions, AG effective activity can be improved by the convective flow through the membrane. UF selectivity for the polymer starch determines effective substrate concentrations in the membrane, thus affecting observed activities and product purities in the filtrate. © 1996 John Wiley & Sons, Inc.     

Yield optimization of a RSFQ voltage doubler

The centers-of-gravity optimization method has been applied to optimize a complex circuit consisting of a dc/SFQ-converter and RSFQ voltage doubler in order to obtain maximum parameter margins. As a result, the margins of all circuit parameters have been enlarged to at least ±35%. This improves the yield of the circuit fabrication process. On the other hand, the upper limiting frequency and the output voltage of the circuit, respectively, are decreased by the yield optimization process.