Methylation of Phenol by Methanol on Acidic Zeolite H–Y Investigated by in situ CF MAS NMR Spectroscopy

In situ ¹³C MAS NMR spectroscopy under continuous-flow (CF) conditions was applied to study the mechanism of the methylation of phenol by methanol on acidic zeolite H–Y. Ex situ GC-MS was used as a complementary technique to confirm the nature of the chemical species remaining on the catalyst after the in situ MAS NMR investigations. Anisole and cresols were observed as the main reaction products in the initial step of the reaction. By use of the stopped-flow (SF) technique, the consecutive transformation of anisole to cresols was observed at the reaction temperature of 413K indicating that anisole is an unstable primary product and an important intermediate.     

SNPs of the FADS Gene Cluster are Associated with Polyunsaturated Fatty Acids in a Cohort of Patients with Cardiovascular Disease

Polymorphisms of the human Δ-5 (FADS1) and Δ-6 (FADS2) desaturase genes have been recently described to be associated with the level of several long-chain n-3 and n-6 polyunsaturated fatty acids (PUFAs) in serum phospholipids. We have genotyped 13 single nucleotide polymorphisms (SNPs) located on the FADS1–FADS2–FADS3 gene cluster (chromosome 11q12–13.1) in 658 Italian adults (78% males; mean age 59.7 ± 11.1 years) participating in the Verona Heart Project. Polymorphisms and statistically inferred haplotypes showed a strong association with arachidonic acid (C20:4n-6) levels in serum phospholipids and in erythrocyte cell membranes (rs174545 adjusted P value for multiple tests, P < 0.0001 and P < 0.0001, respectively). Other significant associations were observed for linoleic (C18:2n-6), alpha-linolenic (C18:3n-3) and eicosadienoic (C20:2n-6) acids. Minor allele homozygotes and heterozygotes were associated to higher levels of linoleic, alpha-linolenic, eicosadienoic and lower levels of arachidonic acid. No significant association was observed for stearidonic (C18:4n-3), eicosapentaenoic (C20:5n-3) and docosahexaenoic (C22:6n-3) acids levels. The observed strong association of FADS gene polymorphisms with the levels of arachidonic acid, which is a precursor of molecules involved in inflammation and immunity processes, suggests that SNPs of the FADS1 and FADS2 gene region are worth studying in diseases related to inflammatory conditions or alterations in the concentration of PUFAs. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Irisin and Secondary Osteoporosis in Humans

Irisin is a peptide secreted by skeletal muscle following exercise that plays an important role in bone metabolism. Numerous experiments in vitro and in mouse models have shown that the administration of recombinant irisin promotes osteogenesis, protects osteocytes from dexamethasone-induced apoptosis, prevents disuse-induced loss of bone and muscle mass, and accelerates fracture healing. Although some aspects still need to be elucidated, such as the dose- and frequency-dependent effects of irisin in cell cultures and mouse models, ample clinical evidence is emerging to support its physiological relevance on bone in humans. A reduction in serum irisin levels, associated with an increased risk of osteoporosis and bone fractures, was observed in postmenopausal women and in both men and women during aging, Recently, cohort studies of subjects with secondary osteoporosis showed that these patients have lower circulating levels of irisin, suggesting that this myokine could be a novel marker to monitor bone quality in this disease. Although there are still few studies, this review discusses the emerging data that are highlighting the involvement of irisin in some diseases that cause secondary osteoporosis.     

Synthesis and Biochemical Evaluation of an Artificial,Fluorescent Glucosinolate (GSL)

The synthesis of the first example of a fluorescent glucosinolate (GSL)–BODIPY conjugate based on an azide-containing artificial GSL precursor (GSL-N₃) is reported. Biochemical evaluation of the artificial GSLs revealed that the compounds are converted to the corresponding isothiocyanates in the presence of myrosinase. Furthermore, myrosinase-catalyzed hydrolysis in the presence of plant specifier proteins yielded the expected alternative products, namely nitriles. The easy assembly of the fluorescent GSL–BODIPY conjugate by click chemistry from GSL-N₃ holds potential for application as a fluorescence labeling tool to investigate GSL-associated processes.     

Development of an Enzyme Mimic Using Self-Selection

The development of a serine protease model using a self-selection protocol is described. The developed system mimics the regeneration step of an enzyme involved in covalent enzyme catalysis. A transition-state analogue of a transesterification reaction is used to self-select functional groups able to accelerate ester cleavage. It is shown that the insertion of a tertiary amine substituent flanking the reaction center reinforces transition-state stabilization by directing the reactive center towards the self-selected functionality. In addition, the tertiary amine activates a bland (solvent) nucleophile for attack on an ester bond similar to what occurs in a serine protease. A quantitative correspondence is observed between the amplification factors and catalytic activity, illustrating the potential of the dynamic covalent capture strategy to precisely detect and quantify weak noncovalent interactions.     

Enantioselective Gas Chromatography with Derivatized Cyclodextrins in the Flavour and Fragrance Field

This article deals with enantioselective gas chromatography (Es-GC) utilizing cyclodextrin derivatives as chiral stationary phases (CSPs) for chiral recognition in the flavour and fragrance field. It consists of two main parts. The first one concerns cyclodextrins and their use in Es-GC, and it deals with their introduction and evolution as CSPs in GC, together with some theoretical aspects involved with enantiomeric separation and their consequent influence on routine chiral recognition. The second part reports on the strategy of chiral recognition in routine analysis with cyclodextrin derivatives as CSP, illustrated with examples from the authors’ everyday experiences. This part describes how to identify enantiomers or to measure their excess or ratio determination in complex mixtures; in particular, it discusses the opportunities offered by multidimensional and fast GC techniques, the role of mass spectrometry, and the application of total analysis systems to chiral recognition.     

Trifluoroethanol Modulates Amyloid Formation by the All α-Helical URN1 FF Domain

Amyloid fibril formation is implicated in different human diseases. The transition between native α-helices and nonnative intermolecular β-sheets has been suggested to be a trigger of fibrillation in different conformational diseases. The FF domain of the URN1 splicing factor (URN1-FF) is a small all-α protein that populates a molten globule (MG) at low pH. Despite the fact that this conformation maintains most of the domain native secondary structure, it progressively converts into β-sheet enriched and highly ordered amyloid fibrils. In this study, we investigated if 2,2,2-trifluoroethanol (TFE) induced conformational changes that affect URN1-FF amyloid formation. Despite TFE having been shown to induce or increase the aggregation of both globular and disordered proteins at moderate concentrations, we demonstrate here that in the case of URN1-FF it reinforces its intrinsic α-helical structure, which competes the formation of aggregated assemblies. In addition, we show that TFE induces conformational diversity in URN1-FF fibrils, in such a way that the fibrils formed in the presence and absence of the cosolvent represent different polymorphs. It is suggested that the effect of TFE on both the soluble and aggregated states of URN1-FF depends on its ability to facilitate hydrogen bonding.     

Tailored electrospun small-diameter graft for vascular prosthesis

There is an unmet need for engineering small vascular graft that can be anastomosed without inducing thrombosis. The objective of this work is to fabricate tubular graft with 2?mm of diameter with biomimetic mechanical and biological properties. Poly(ε-caprolactone) and poly(glycerol sebacate) blends with different concentrations and ratios are used to fabricate fibrous grafts using electrospinning process. Porous and degradable scaffolds with enhanced mechanical properties and comparable suture retention to the native human artery are fabricated. Scaffold–blood interaction revealed good anticoagulation properties. The fabricated constructs can serve as biocompatible and hemocompatible vascular graft with enhanced mechanical properties.