Standardisierte Persönlichkeitsdiagnostik und Behandlungsevaluation : methodenkritische Analyse der Handhabung im Strafvollzug

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NAD(H)-coupled hydrogen cycling - structure-function relationships of bidirectional [NiFe] hydrogenases

Hydrogenases catalyze the activation or production of molecular hydrogen. Due to their potential importance for future biotechnological applications, these enzymes have been in the focus of intense research for the past decades. Bidirectional [NiFe] hydrogenases are of particular interest as they couple the reversible cleavage of hydrogen to the redox conversion of NAD(H). In this account, we review the current state of knowledge about mechanistic aspects and structural determinants of these complex multi-cofactor enzymes. Special emphasis is laid on the oxygen-tolerant NAD(H)-linked bidirectional [NiFe] hydrogenase from Ralstonia eutropha. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved

H-2-driven biotransformation of n-octane to 1-octanol by a recombinant Pseudomonas putida strain co-synthesizing an O-2-tolerant hydrogenase and a P450 monooxygenase

An in vivo biotransformation system is presented that affords the hydroxylation of n-octane to 1-octanol on the basis of NADH-dependent CYP153A monooxygenase and NAD(+)-reducing hydrogenase heterologously synthesized in a bacterial host. The hydrogenase sustains H-2-driven NADH cofactor regeneration even in the presence of O-2, the co-substrate of monooxygenase.DFG, EXC 314, Unifying Concepts in CatalysisEC/FP7/297503/EU/Modular beads for regeneration of bio-cofactors in enzyme-catalysed synthesis/HydRege

Polizei im Wandel: Das Erhebungsinstrument der standardisierten Befragung der Vollzugsbeamtinnen und -beamten der niedersächsichen Polizei 2001

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Polizei im Wandel: Abschlussbericht der standardisierten Befragung der Vollzugsbeamtinnen und -beamten der niedersächsischen Polizei 2001 sowie erste Ergebnisse der Gruppendiskussionen 2002

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Enzymatic and spectroscopic properties of a thermostable [NiFe]‑hydrogenase performing H2-driven NAD+-reduction in the presence of O2

Biocatalysts that mediate the H2-dependent reduction of NAD+ to NADH are attractive from both a fundamental and applied perspective. Here we present the first biochemical and spectroscopic characterization of an NAD+-reducing [NiFe]‑hydrogenase that sustains catalytic activity at high temperatures and in the presence of O2, which usually acts as an inhibitor. We isolated and sequenced the four structural genes, hoxFUYH, encoding the soluble NAD+-reducing [NiFe]‑hydrogenase (SH) from the thermophilic betaproteobacterium, Hydrogenophilus thermoluteolus TH-1T (Ht). The HtSH was recombinantly overproduced in a hydrogenase-free mutant of the well-studied, H2-oxidizing betaproteobacterium Ralstonia eutropha H16 (Re). The enzyme was purified and characterized with various biochemical and spectroscopic techniques. Highest H2-mediated NAD+ reduction activity was observed at 80 °C and pH 6.5, and catalytic activity was found to be sustained at low O2 concentrations. Infrared spectroscopic analyses revealed a spectral pattern for as-isolated HtSH that is remarkably different from those of the closely related ReSH and other [NiFe]‑hydrogenases. This indicates an unusual configuration of the oxidized catalytic center in HtSH. Complementary electron paramagnetic resonance spectroscopic analyses revealed spectral signatures similar to related NAD+-reducing [NiFe]‑hydrogenases. This study lays the groundwork for structural and functional analyses of the HtSH as well as application of this enzyme for H2-driven cofactor recycling under oxic conditions at elevated temperatures

Mesaconate is synthesized from itaconate and exerts immunomodulatory effects in macrophages.

peer reviewedSince its discovery in inflammatory macrophages, itaconate has attracted much attention due to its antimicrobial and immunomodulatory activity1-3. However, instead of investigating itaconate itself, most studies used derivatized forms of itaconate and thus the role of non-derivatized itaconate needs to be scrutinized. Mesaconate, a metabolite structurally very close to itaconate, has never been implicated in mammalian cells. Here we show that mesaconate is synthesized in inflammatory macrophages from itaconate. We find that both, non-derivatized itaconate and mesaconate dampen the glycolytic activity to a similar extent, whereas only itaconate is able to repress tricarboxylic acid cycle activity and cellular respiration. In contrast to itaconate, mesaconate does not inhibit succinate dehydrogenase. Despite their distinct impact on metabolism, both metabolites exert similar immunomodulatory effects in pro-inflammatory macrophages, specifically a reduction of interleukin (IL)-6 and IL-12 secretion and an increase of CXCL10 production in a manner that is independent of NRF2 and ATF3. We show that a treatment with neither mesaconate nor itaconate impairs IL-1β secretion and inflammasome activation. In summary, our results identify mesaconate as an immunomodulatory metabolite in macrophages, which interferes to a lesser extent with cellular metabolism than itaconate

Catalytic Production of Hydrogen Peroxide and Water by Oxygen-Tolerant [NiFe]-Hydrogenase during H₂ Cycling in the Presence of O₂

Hydrogenases control the H₂-related metabolism in many microbes. Most of these enzymes are prone to immediate inactivation by O₂. However, a few members of the subclass of [NiFe]-hydrogenases are able to convert H₂ into protons and electrons even in the presence of O₂, making them attractive for biotechnological application. Recent studies on O₂-tolerant membrane-bound hydrogenases indicate that the mechanism of O₂ tolerance relies on their capability to completely reduce O₂ with four electrons to harmless water. In order to verify this hypothesis, we probed the O₂ reduction capacity of the soluble, NAD⁺-reducing [NiFe]-hydrogenase (SH) from <i>Ralstonia eutropha</i> H16. A newly established, homologous overexpression allowed the purification of up to 90 mg of homogeneous and highly active enzyme from 10 g of cell material. We showed that the SH produces trace amounts of superoxide in the course of H₂-driven NAD⁺ reduction in the presence of O₂. However, the major products of the SH-mediated oxidase activity was in fact hydrogen peroxide and water as shown by the mass spectrometric detection of H₂¹⁸O formed from H₂ and isotopically labeled ¹⁸O₂. Water release was also observed when the enzyme was incubated with NADH and ¹⁸O₂, demonstrating the importance of reverse electron flow to the [NiFe] active site for O₂ reduction. A comparison of the turnover rates for H₂ and O₂ revealed that in the presence of twice the ambient level of O₂, up to 3% of the electrons generated through H₂ oxidation serve as “health insurance” and are reused for O₂ reduction

High-Pressure Synthesis, Electron Energy-Loss Spectroscopy Investigations, and Single Crystal Structure Determination of a Spinel-Type Gallium Oxonitride Ga2.79◻0.21(O3.05N0.76◻0.19)

Under high-pressure/high-temperature conditions of 5 GPa and 1250 °C, the cubic phase Ga2.790.21(O3.05N0.760.19) ( = vacancy) was synthesized in a Walker-type multianvil apparatus. For the first time, the crystal structure of a gallium oxonitride was determined on the basis of single crystal X-ray diffraction data. The cubic spinel-type gallium oxonitride crystallizes in the space group Fd3̅m (No. 227) with a lattice parameter a0 = 827.8(2) pm. The combination of energy-dispersive X-ray spectroscopy (EDS) with electron energy-loss spectroscopy (EELS) allowed the quantification of nitrogen and oxygen for structural refinement. In the literature dealing with oxonitrides, crystal defects in spinel-type materials are handled with different models, mainly the approximation of a constant anion model. The present results indicate that this model is questionable, and one should also take into account a model with both cation and anion vacancies. Furthermore, a linear relationship between the lattice parameters and the ratio N/O in the gallium oxonitrides is questionable