Co-Oxidative Transformation of Piperine to Piperonal and 3,4-Methylenedioxycinnamaldehyde by a Lipoxygenase from Pleurotus sapidus

The valuable aroma compound piperonal with its vanilla-like olfactory properties is of high interest for the fragrance and flavor industry. A lipoxygenase (LOX_Psa1) of the basidiomycete Pleurotus sapidus was identified to convert piperine, the abundant pungent principle of black pepper (Piper nigrum), to piperonal and a second volatile product, 3,4-methylenedioxycinnamaldehyde, with a vanilla-like odor through an alkene cleavage. The reaction principle was co-oxidation, as proven by its dependence on the presence of linoleic or α-linolenic acid, common substrates of lipoxygenases. Optimization of the reaction conditions (substrate concentrations, reaction temperature and time) led to a 24-fold and 15-fold increase of the piperonal and 3,4-methylenedioxycinnamaldehyde concentration using the recombinant enzyme. Monokaryotic strains showed different concentrations of and ratios between the two reaction products.     

Effect of Methionine Sulfoxide on the Synthesis and Purification of Aggregation-Prone Peptides

A two-step synthesis for methionine-containing hydrophobic and/or aggregation-prone peptides is presented that takes advantage of the reversibility of methionine oxidation. The use of polar methionine sulfoxide as a building block in solid-phase peptide synthesis improves the synthesis quality and yields the crude peptide, with significantly improved solubility compared to the reduced species. This facilitates the otherwise often laborious peptide purification by high-performance liquid chromatography. The subsequent reduction proceeds quantitatively. This approach has been optimised with the methionine-rich Tar-DNA-binding protein 43 (307–347), but is also more generally applicable, as demonstrated by the syntheses of human calcitonin and two aggregation-prone peptides from the human prion protein.     

Rapid On-Resin N-Formylation of Peptides as One-Pot Reaction

N-formylation is a common pre- and post-translational modification of the N-terminus or the lysine side chain of peptides and proteins that plays a role in the initiation of immune responses, gene expression, or epigenetics. Despite its high biological relevance, protocols for the chemical N-formylation of synthetic peptides are scarce. The few available methods are elaborate in their execution and the yields are highly sequence-dependent. We present a rapid, easy-to-use one-pot procedure that runs at room temperature and can be used to formylate protected peptides at both the N-terminus and the lysine side chain on the resin in near-quantitative yields. Only insensitive, storage-stable standard chemicals – formic acid, acetic anhydride, pyridine and DMF – are used. Formylation works for both short and long peptides of up to 34 amino acids and over the spectrum of canonical amino acids.     

Status quo on identified transformation products of organic ultraviolet filters and their persistence

Organic micropollutants of concern—including organic UV filters (UVF)—are getting increasing attention. Personal care products such as sunscreens or cosmetic articles often contain large quantities of UVF. These substances enter the environment either directly (during outdoor activities) or indirectly (via sewages from households). Therefore, the removal or degradation of UVF by natural or technical treatment processes is important to understand. UVF are often incompletely removed and transformed to side products of incomplete mineralization by abiotic and biotic processes. An extensive overview on transformation products (TPs) is essential to systematically identify knowledge gaps and to derive research needs. While there are many reviews on the UVF themselves, the number of reviews which focus on their TPs is limited. Consequently, this review gives an overview on the latest findings regarding TPs of UVF. In this publication, known TPs of UVF, which were formed during abiotic and biotic processes, are reviewed. Target substances were defined and a literature database was reviewed for studies on TPs of the target substances. The first list of studies was shortened stepwise, thus generating a final list of studies which contained only the relevant studies. Since biodegradation is one of the most important pathways for removal of organic compounds from the environment, this review presents an overview on known TPs of organic UVF and their biodegradability, which determines their environmental fate. In this way, all identified TPs of UVF were listed and checked for information on their biodegradability. A total of 2731 records of studies were assessed. Forty-two studies, which assessed 46 processes that lead to the formation of identified TPs, were included in this review. One hundred and seventyseven different TPs resulting from 11 different UVF were identified. Little to no data on the biodegradability was found for TPs. This indicates a severe lack of data on the biodegradability of TPs of organic UVF substances. Since most TPs lack information on biodegradability, further research should provide information on both—identity and biodegradability—of formed TPs to be able to assess their hazardousness for the environment.     

Was ist Qualit?t im Gesundheitswesen?

Definition of the problem With the introduction of diagnosis-related groups, German hospitals were obliged to develop quality assurance schemes. This article analyses (1) commonly used definitions for quality in health care and (2) their implementation in terms of interventions for improving quality in hospitals.Arguments Consequences of current quality assurance practices include advances in objective quality, but also a shift within the culture of medicine towards dividing the treatment of patients into measurable and standardized steps. In contrast to this objective meaning of quality, there is a demand for more patient orientation and for more attention to the subjective quality of treatment which refers to a therapeutic interaction-based notion of quality standards. Besides technical quality standards, there are important quality standards that are being defined in and through interpersonal therapeutic interaction.Conclusion Good hospital management should, therefore, protect the cultivation of therapeutic interaction in its essentially interpersonal qualities.     

Synthesis,characterization and in situ monitoring of the mechanochemical reaction process of two manganese(II)-phosphonates with N-containing ligands

Two divalent manganese aminophosphonates, manganese mono(nitrilotrimethylphosphonate) (MnNP₃) and manganese bis(N-(carboxymethyl)iminodi(methylphosphonate)) (Mn(NP₂AH)₂), have been prepared by mechanochemical synthesis and characterized by powder X-ray diffraction (PXRD). The structure of the novel compound Mn(NP₂AH)₂ was determined from PXRD data. MnNP₃ as well as Mn(NP₂AH)₂ exhibits a chain-like structure. In both cases, the manganese atom is coordinated by six oxygen atoms in a distorted octahedron. The local coordination around Mn was further characterized by extended X-ray absorption fine structure. The synthesis process was followed in situ by synchrotron X-ray diffraction revealing a three-step reaction mechanism. The as-prepared manganese(II) phosphonates were calcined on air. All samples were successfully tested for their suitability as catalyst material in the oxygen evolution reaction.     

Crystallization and microstructure of a glass seal for rapid laser sealing in the system CaO/Al<Subscript>2</Subscript>O<Subscript>3</Subscript>/SiO<Subscript>2</Subscript>

A glass with the composition 61 CaO·30 Al₂O₃·9 SiO₂ was studied with respect to its crystallization behavior and its suitability as a rapidly crystallizing material for laser sealing. The glass was studied by differential scanning calorimetry; from the profiles recorded, Avrami activation energies and Avrami coefficients were calculated. The latter are in the range between 0.99 and 1.55 which is supposedly attributed to sole surface crystallization. During thermal treatment as well as during laser sealing, Ca₁₂Al₁₄O₃₃, CaAl₂O₄ and Ca₃Al₂O₆ are formed. These phases were also observed in SEM micrographs as evidenced by electron backscatter diffraction from the attributed Kikuchi patterns. Transmission electron microscopy showed a crystallized CaO- and SiO₂-enriched interface which strongly adhered to the Al₂O₃ ceramic. The porosity of the crystallized seal was in the order of few percent. The studied glass proved suitable as crystallizing seal for rapid laser sealing.