Reconstitution of Nucleosome Demethylation and Catalytic Properties of a Jumonji Histone Demethylase

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Highlights? Catalytic domain of JMJD2A (cJMJD2A) removes methyl marks in a distributive manner ? Homogeneously methylated nucleosomes were used as substrates ? Quantitative assay for nucleosome demethylation has been developed     

Map operations and k-orbit maps

A k-orbit map is a map with k flag-orbits under the action of its automorphism group. We give a basic theory of k-orbit maps and classify them up to k?4. “Hurwitz-like” upper bounds for the cardinality of the automorphism groups of 2-orbit and 3-orbit maps on surfaces are given. Furthermore, we consider effects of operations like medial and truncation on k-orbit maps and use them in classifying 2-orbit and 3-orbit maps on surfaces of small genus.     

Synthesis of pyrazino[1,2-a]benzimidazol-1(2H)ones via a microwave assisted Buchwald-Hartwig type reaction

A convenient synthesis of substituted pyrazino[1,2-a]benzimidazol-1(2H)ones starting from 3,5-dichloropyrazinones has been accomplished. Various 3-anilino-pyrazinones were easily converted to the desired tricyclic structures by applying a microwave assisted Buchwald-Hartwig type cyclization.     

Ultra-thin-layer chromatography mass spectrometry and thin-layer chromatography mass spectrometry of single peptides of angiotensin-converting enzyme inhibitors

The separation of structurally related angiotensin-converting enzyme (ACE) inhibitors lisinopril, cilazapril, ramipril and quinapril and their corresponding active diacid forms (prilates) by conventional TLC silica gel 60 plates was contrasted with that afforded by monolithic ultra-thin-layer chromatographic (UTLC) plates. For the use of UTLC plates technical modifications of the commercially available equipments for the sample application, development and detection were made. Plates were developed in modified horizontal developing chamber using ethyl acetate-acetone-acetic acid-water (4:1:0.25:0.5, v/v). Detection of the separated compounds was performed densitometrically in absorption/reflectance mode at 220 nm and after exposure to iodine also by image analysis. The obtained results showed that monolithic layer is more efficient for the separation of structurally similar polar compounds, such as prilates than conventional silica layers. Identification of the compounds was confirmed by ESI-MS after their on-line extraction from the UTLC and TLC plates by means of Camag TLC-MS interface.     

Epidemic centrality — is there an underestimated epidemic impact of network peripheral nodes?

In the study of disease spreading on empirical complex networks in SIR model, initially infected nodes can be ranked according to some measure of their epidemic impact. The highest ranked nodes, also referred to as “superspreaders”, are associated to dominant epidemic risks and therefore deserve special attention. In simulations on studied empirical complex networks, it is shown that the ranking depends on the dynamical regime of the disease spreading. A possible mechanism leading to this dependence is illustrated in an analytically tractable example. In systems where the allocation of resources to counter disease spreading to individual nodes is based on their ranking, the dynamical regime of disease spreading is frequently not known before the outbreak of the disease. Therefore, we introduce a quantity called epidemic centrality as an average over all relevant regimes of disease spreading as a basis of the ranking. A recently introduced concept of phase diagram of epidemic spreading is used as a framework in which several types of averaging are studied. The epidemic centrality is compared to structural properties of nodes such as node degree, k-cores and betweenness. There is a growing trend of epidemic centrality with degree and k-cores values, but the variation of epidemic centrality is much smaller than the variation of degree or k-cores value. It is found that the epidemic centrality of the structurally peripheral nodes is of the same order of magnitude as the epidemic centrality of the structurally central nodes. The implications of these findings for the distributions of resources to counter disease spreading are discussed.     

Synthesis of 2(1H)-pyrazinone phosphonates via an Arbuzov-type reaction

A simple and catalyst-free method for the synthesis of phosphonated 2(1H)-pyrazinones is described starting from 3,5-dichloropyrazinones. The method also works for 3-bromo- and 3-iodopyrazinones. Classical heating conditions as well as microwave-enhanced reaction conditions were tested.     

Design and synthesis of novel type VI-like β-turn mimetics. Diversity at the i+1 and the i+2 position

In this paper, a synthetic approach for functionalised 5-aminopiperidinone-2-carboxylate (APC) systems as non-pro cis-peptide bond containing external β-turn mimics is presented. The scope and limitations of the synthetic method are discussed and the potential turn inducing properties of a model compound are evaluated by means of molecular modelling and NMR analysis.     

Fiber-optic flow-through sensor for online monitoring of glucose

A new microdialysis-based glucose-sensing system with an integrated fiber-optic hybrid sensor is presented. Design and dimensions of the cell are adapted for its coupling with commercially available microdialysis techniques, thereby providing a new system for continuous glucose monitoring. The glucose level is detected via oxygen consumption which occurs as a consequence of enzymatic reaction between immobilized glucose oxidase and glucose. The use of gas-permeable Tygon tubing ensures complete and constant air-saturation of the measuring fluid in the cell. Nevertheless, a reference oxygen optode is used to detect and to compensate response changes caused by events like bacterial growth, temperature fluctuations, or failure of the peristaltic pump. In contrast to widely used electrochemical sensors, the response of the microdialysis-based fiber-optic glucose sensor is highly selective, making this sensor approach particularly advantageous for continuous glucose monitoring of patients in intensive care units. The effects of flow rate, pH, temperature, and common interferences on the sensor response are presented and discussed in detail. The sensor is evaluated in vitro using a 3-day continuous test in glucose-spiked plasma. The ability to measure glucose in humans is demonstrated by coupling the flow-through cell and commercially available microdialysis catheter CMA60. A 24-h monitoring test using this setup is successfully applied to a healthy volunteer.