Pyridine as novel substrate for regioselective oxygenation with aromatic peroxygenase from Agrocybe aegerita

AbstractAgrocybe aegerita peroxidase (AaP) is a versatile extracellular biocatalyst that can oxygenate aromatic compounds. Here, we report on the selective oxidation of pyridine (PY) yielding pyridine N-oxide as sole product. Using H218O2 as co-substrate, the origin of oxygen was confirmed to be the peroxide. Therefore, AaP can be regarded as a true peroxygenase transferring one oxygen atom from peroxide to the substrate. To our best knowledge, there are only two types of enzymes oxidizing PY at the nitrogen: bacterial methane monooxygenase and a few P450 monooxygenases. AaP is the first extracellular enzyme and the first peroxidase that catalyzes this reaction, and it converted also substituted PYs into the corresponding N-oxides

Nuclear Shape Effect on the g Factor of Hydrogenlike Ions

The nuclear shape correction to the g factor of a bound electron in 1S-state is calculated for a number of nuclei in the range of charge numbers from Z=6 up to Z=92. The leading relativistic deformation correction has been derived analytically and also its influence on one-loop quantum electrodynamic terms has been evaluated. We show the leading corrections to become significant for mid-Z ions and for very heavy elements to even reach the 10^(-6) level.Comment: 4 pages, 1 figur

The interplay of incentives and mode-choice design in self-administered mixed-mode surveys

Self-administered mixed-mode surveys are increasingly used as an alternative to face-to-face surveys for collecting data from the general population. However, little is known about how decisions regarding the incentive scheme and the mode-choice design jointly affect key outcomes such as response rates, net sample composition, and survey costs. To study this, we drew a probability sample of the residential population of the city of Mannheim, Germany (N = 2,980) and randomly assigned target persons to one of four incentive schemes (€0, €1, or €2 prepaid incentive on first contact, and €2 delayed prepaid incentive) and one of two mode-choice designs (concurrent or sequential [web-push]). Our results indicate that small prepaid monetary incentives work better in concurrent than in sequential designs. Moreover, a €2 prepaid incentive in a concurrent design proved particularly successful for older target persons, probably reinforcing their sense of trust and reciprocity, while also fitting better with their survey-mode preferences. Finally, a €2 delayed prepaid incentive in a sequential design primarily motivated target persons aged under 50 years. This combination of incentive scheme and mode-choice design also proved to be most cost-effective in that age group. Based on our results, we recommend using sampling frame information on age to address different age groups with different combinations of incentive scheme and mode-choice design. This may help to maximize response rates, achieve a balanced net sample composition, and minimize survey costs

Politiken der Kindheit

The publication of this work was supported by the Open Access Publication Fund of Humboldt-Universität zu Berlin.Die sozialwissenschaftliche Kindheitsforschung wird seit ihrem Entstehen von politischen Argumenten begleitet. Die Auseinandersetzung mit Kindern und Kindheit ist somit nicht von einer politischen Dimension zu trennen und gibt Anlass, Fragen nach der politischen Dimension nicht nur von Kindheit, sondern auch der Kindheitsforschung zu stellen. Der Sammelband beleuchtet systematisch die vielfältigen Beziehungen zwischen Kindheit und Politik und macht auch neuere Diskussionen im Feld der sozialwissenschaftlichen Kindheitsforschung sichtbar. Im Mittelpunkt des Interesses stehen Fragen nach den differenten Modi und Zielen der Inanspruchnahme von Kindern und Kindheit in und durch Politik, nach den (nicht-)intendierten Konsequenzen politischer Prozesse auf Kinder und Kindheit, nach zentralen Paradoxien im Bezug von politischen Akteur:innen auf Kinder und Kindheit, aber auch grundsätzlich der Ent-/Politisierung von Kindern und durch Kinder

Subcellular distribution of the V-ATPase complex in plant cells, and in vivo localisation of the 100 kDa subunit VHA-a within the complex

BACKGROUND: Vacuolar H(+)-ATPases are large protein complexes of more than 700 kDa that acidify endomembrane compartments and are part of the secretory system of eukaryotic cells. They are built from 14 different (VHA)-subunits. The paper addresses the question of sub-cellular localisation and subunit composition of plant V-ATPase in vivo and in vitro mainly by using colocalization and fluorescence resonance energy transfer techniques (FRET). Focus is placed on the examination and function of the 95 kDa membrane spanning subunit VHA-a. Showing similarities to the already described Vph1 and Stv1 vacuolar ATPase subunits from yeast, VHA-a revealed a bipartite structure with (i) a less conserved cytoplasmically orientated N-terminus and (ii) a membrane-spanning C-terminus with a higher extent of conservation including all amino acids shown to be essential for proton translocation in the yeast. On the basis of sequence data VHA-a appears to be an essential structural and functional element of V-ATPase, although previously a sole function in assembly has been proposed. RESULTS: To elucidate the presence and function of VHA-a in the plant complex, three approaches were undertaken: (i) co-immunoprecipitation with antibodies directed to epitopes in the N- and C-terminal part of VHA-a, respectively, (ii) immunocytochemistry approach including co-localisation studies with known plant endomembrane markers, and (iii) in vivo-FRET between subunits fused to variants of green fluorescence protein (CFP, YFP) in transfected cells. CONCLUSIONS: All three sets of results show that V-ATPase contains VHA-a protein that interacts in a specific manner with other subunits. The genomes of plants encode three genes of the 95 kDa subunit (VHA-a) of the vacuolar type H(+)-ATPase. Immuno-localisation of VHA-a shows that the recognized subunit is exclusively located on the endoplasmic reticulum. This result is in agreement with the hypothesis that the different isoforms of VHA-a may localize on distinct endomembrane compartments, as it was shown for its yeast counterpart Vph1

Clumped isotope thermometry of cryogenic cave carbonates

Abstract Freezing of cave pool water that is increasingly oversaturated with dissolved carbonate leads to precipitation of a very specific type of speleothems known as cryogenic cave carbonates (CCC). At present, two different environments for their formation have been proposed, based on their characteristic carbon and oxygen isotope ratios. Rapidly freezing thin water films result in the fast precipitation of fine-grained carbonate powder (CCC fine ). This leads to rapid physicochemical changes including CO 2 degassing and CaCO 3 precipitation, resulting in significantly 13 C-enriched carbonates. Alternatively, slow carbonate precipitation in ice-covered cave pools results in coarse crystalline CCC (CCC coarse ) yielding strongly 18 O-depleted carbonate. This is due to the formation of relatively 18 O-enriched ice causing the gradual depletion of 18 O in the water from which the CCC precipitates. Cryogenic carbonates from Central European caves were found to have been formed primarily during the last glacial period, specifically during times of permafrost thawing, based on the oxygen isotope ratios and U-Th dating. Information about the precise conditions of CCC coarse formation, i.e. whether these crystals formed under equilibrium or disequilibrium conditions with the parent fluid, however, is lacking. An improved understanding of CCC coarse formation will increase the predictive value of this paleo-permafrost archive. Here we apply clumped isotopes to investigate the formation conditions of cryogenic carbonates using well-studied CCC coarse from five different cave systems in western Germany. Carbonate clumped isotope measurements yielded apparent temperatures between 3 and 18°C and thus exhibit clear evidence of isotopic disequilibrium. Although the very negative carbonate d 18 O values can only be explained by gradual freezing of pool water accompanied by preferential incorporation of 18 O into the ice, clumped isotope-derived temperatures significantly above expected freezing temperatures indicate incomplete isotopic equilibration during precipitation of CCC

Shortened Tracer Uptake Time in GA-68-DOTATOC-PET of Meningiomas Does Not Impair Diagnostic Accuracy and PET Volume Definition

Ga-68-DOTATOC-PET/MRI can affect the planning target volume (PTV) definition of meningiomas before radiosurgery. A shorter tracer uptake time before image acquisition could allow the examination of more patients. The aim of this study was to investigate if shortening uptake time is possible without compromising diagnostic accuracy and PET volume. Fifteen patients (f = 12; mean age 52 years (34-80 years)) with meningiomas were prospectively examined with dynamic [68Ga]Ga-68-labeled [DOTA0-Phe1-Tyr3] octreotide (Ga-68-DOTATOC)-PET/MRI over 70 min before radiosurgery planning. Meningiomas were delineated manually in the PET dataset. PET volumes at each time point were compared to the reference standard 60 min post tracer injection (p.i.) using the Friedman test followed by a Wilcoxon signed-rank test and Bonferroni correction. In all patients, the earliest time point with 100% lesion detection compared to 60 min p.i. was identified. PET volumes did not change significantly from 15 min p.i. (p = 1.0) compared to 60 min p.i. The earliest time point with 100% lesion detection in all patients was 10 min p.i. In patients with meningiomas undergoing Ga-68-DOTATOC-PET, the tracer uptake time can safely be reduced to 15 min p.i. with comparable PET volume and 100% lesion detection compared to 60 min p.i