α-N-Linked glycopeptides: conformational analysis and bioactivity as lectin ligands

Natural N-glycosylation involves a β-anomeric linkage connecting the sugar to one asparagine residue of the protein. We herein report NMR- and modelling-based data on glycomimetics containing α-glycosidic linkages. The bioactivity of α-Gal-containing glycopeptides has been documented by revealing binding to two plant lectins, i.e. a potent β-trefoil toxin (Viscum album agglutinin) and β-sandwich lectin (Erythrina corallodendron agglutinin), by NMR protocols. Docking provided insights into the 3D structures of the resulting complexes. These results provide the basis to introduce α-substituted neoglycopeptides to the toolbox of scaffold for the design of potent lectin inhibitors.     

DNA separation by capillary electrophoresis with hydrophilic substituted celluloses as coating and sieving polymers. Application to the analysis of genetically modified meals

A coating procedure based on the physical adsorption of hydroxypropyl cellulose onto the wall of a capillary column has been successfully used for the separation of DNA fragments up to 500 bp. The method uses a running Tris-phosphate-EDTA buffer containing 2-hydroxyethyl cellulose as sieving polymer. The separation procedure shows good reproducibility (measured as RSD%) for consecutive runs (<0.64), for different days (< 1.15) and capillaries (<2.15), short analysis times, and a long coating lifetime. Good reproducibility and efficiency are even achieved by performing the separation in the presence of additives such as ethidium bromide and mannitol. The method is applied to the detection of GMOs in soybean and maize meals with an accurate evaluation of the length of DNA sequences, previously amplified by polymerase chain reaction.     

A theoretical study of the solvent effect on Diels-Alder reaction in room temperature ionic liquids using a supermolecular approach

The Diels-Alder reaction between cyclopentadiene and three dienophiles (acrolein, methyl acrylate and acrylonitrile) in different room temperature ionic liquids containing imidazolium-based cations ([HBIM]⁺, [BMIM]⁺ and [BM₂IM]⁺) has been studied at the DFT level using a supermolecular approach. An analysis of the theoretical results shows that the ionic liquid cation coordination affects the equilibrium geometries and electronic structures of the reacting species throughout the reaction pathway leading to changes in reactivity and selectivity. They also indicate that the strong asynchronicity of the Diels-Alder reactions in ionic liquids is due to the polarisation effect of the cation.     

New solid mucoadhesive systems for benzydamine vaginal administration

The aim of this work was the realization of new formulations for vaginal application to improve the pharmacological effect of benzydamine, displaying both anti-inflammatory and antiseptic activities. For this reasons, this drug was formulated in solid dispersions, by using the mucoadhesive polymers HPMC and/or Carbopol(?), then compressed. Tablets were characterized by studies of friability, hardness, hydration, DSC, mucoadhesion and in vitro release. Kinetics, responsible for drug delivery, was investigated as well. Tablets prepared by using only HPMC showed the best results in terms of swelling and mucoadhesion (time and force) together with prolonged and complete drug release, by diffusive mechanism, through gelled layer. Despite the good mucoadhesive properties, Carbopol(?) does not represent a good excipient because, after the contact with water, it generates a spongy gel layer, not homogeneous, stiff, brittle and with breaking tendency when highly swelled. This kind of gel does not guarantee a linear drug release and could provoke discomfort because of fragment release. HPMC mucoadhesive tablets could be a proper delivery system for benzydamine administration representing a good alternative to traditional dosage forms for vaginal topical therapy.     

New Designs for Phototherapeutic Transition Metal Complexes

In this Minireview, we highlight recent advances in the design of transition metal complexes for photodynamic therapy (PDT) and photoactivated chemotherapy (PACT), and discuss the challenges and opportunities for the translation of such agents into clinical use. New designs for light‐activated transition metal complexes offer photoactivatable prodrugs with novel targeted mechanisms of action. Light irradiation can provide spatial and temporal control of drug activation, increasing selectivity and reducing side‐effects. The photophysical and photochemical properties of transition metal complexes can be controlled by the appropriate choice of the metal, its oxidation state, the number and types of ligands, and the coordination geometry.     

Low affinity PEGylated hemoglobin from Trematomus bernacchii, a model for hemoglobin-based blood substitutes

Background

The majority of peroxisomal matrix proteins destined for translocation into the peroxisomal lumen are recognised via a C-terminal Peroxisomal Target Signal type 1 by the cycling receptor Pex5p. The only structure to date of Pex5p in complex with a cargo protein is that of the C-terminal cargo-binding domain of the receptor with sterol carrier protein 2, a small, model peroxisomal protein. In this study, we have tested the contribution of a second, ancillary receptor-cargo binding site, which was found in addition to the characterised Peroxisomal Target Signal type 1.

Results

To investigate the function of this secondary interface we have mutated two key residues from the ancillary binding site and analyzed the level of binding first by a yeast-two-hybrid assay, followed by quantitative measurement of the binding affinity and kinetics of purified protein components and finally, by in vivo measurements, to determine translocation capability. While a moderate but significant reduction of the interaction was found in binding assays, we were not able to measure any significant defects in vivo.

Conclusions

Our data therefore suggest that at least in the case of sterol carrier protein 2 the contribution of the second binding site is not essential for peroxisomal import. At this stage, however, we cannot rule out that other cargo proteins may require this ancillary binding site.     

Harnessing the Liquid‐Phase Exfoliation of Graphene Using Aliphatic Compounds: A Supramolecular Approach

The technological exploitation of the extraordinary properties of graphene relies on the ability to achieve full control over the production of a high‐quality material and its processing by up‐scalable approaches in order to fabricate large‐area films with single‐layer or a few atomic‐layer thickness, which might be integrated in working devices. A simple method is reported for producing homogenous dispersions of unfunctionalized and non‐oxidized graphene nanosheets in N‐methyl‐2‐pyrrolidone (NMP) by using simple molecular modules, which act as dispersion‐stabilizing compounds during the liquid‐phase exfoliation (LPE) process, leading to an increase in the concentration of graphene in dispersions. The LPE‐processed graphene dispersion was shown to be a conductive ink. This approach opens up new avenues for the technological applications of this graphene ink as low‐cost electrodes and conducting nanocomposite for electronics.     

Validation of ELISA methods for search and quantification of β-n-methylamino-l-alanine in water and fish tissue

Water basins with low hydrodynamic activities can promote the growth and increase in algal biomass due to eutrophication, and toxic cyanobacteria species might then produce metabolites hazardous to human health. Over the last decade, a neurotoxic non-protein amino acid, (2S)-2-amino-3-(methylamino) propanoic acid, known as β-N-methylamino-L-alanine (BMAA), has become of particular interest because it has been hypothesised to be involved in progressive human neurodegenerative pathologies. This toxin can be found both in algal cells and free in water, as well as in some foods of aquatic and terrestrial origin. Analytical methods used for BMAA are often based on chromatography coupled with mass spectrometry, although these techniques involve long and expensive analysis. As the availability of a faster and cheaper screening method would be useful, we tested the only available Enzyme-Linked Immunosorbent Assay kit for BMAA evaluation and validated methods to verify their reliability for the analysis of water and fish muscle. For both matrices, we determined adequate selectivity and repeatability (relative standard deviation < 6%), with recoveries from 70% to 83% at the tested spiking levels; the methods were also robust. These data appear in contrast to a previous evaluation carried out on the same kit in 2013, although this might depend on an improvement to the kit performance. We can conclude that a preliminary determination of BMAA in water, and also in fish tissue after an adequate extraction procedure, can be performed efficiently with the tested kit, which provides for easier monitoring of this dangerous toxin.     

Comparison of pyrimethanil-imprinted beads and bulk polymer as stationary phase by non-linear chromatography

A pyrimethanil-imprinted polymer (P1) was prepared by iniferter-mediated photografting a mixture of methacrylic acid and ethylene dimethacrylate onto homemade near-monodispersed chloromethylated polydivinylbenzene beads. The chromatographic behaviour of a column packed with these imprinted beads was compared with another column packed with irregular particles obtained by grinding a bulk pyrimethanil-imprinted polymer (P2). The comparison was made using the kinetic model of non-linear chromatography, studying the elution of the template and of two related substances, cyprodinil and mepanipyrim. Extension of the region of linearity, capacity factors for the template and the related substances, column selectivity, binding site heterogeneity, apparent affinity constant (K) and lumped kinetic association (k_a) and dissociation rate constant (k_d) were studied during a large interval of solute concentration, ranging between 1 and 2000 μg/ml. From the experimental results obtained, in the linearity region of solute concentration column selectivity and binding site heterogeneity remained essentially the same for the two columns, while column capacity (at 20 μg/ml, P1 = 23.1, P2 = 11.5), K (at 20 μg/ml, P1 = 8.3 × 10⁶ M⁻¹, P2 = 2.5 × 10⁶ M⁻¹) and k_a (at 20 μg/ml, P1 = 3.5 μM⁻¹ s⁻¹, P2 = 0.47 μM⁻¹ s⁻¹) significantly increased and k_d (at 20 μg/ml, P1 = 0.42 s⁻¹, P2 = 0.67 s⁻¹) decreased for the column packed with the imprinted beads. These results are consistent with an influence of the polymerisation method on the morphology of the resulting polymer and not on the molecular recognition properties due to the molecular imprinting process.     

Dried Destoned Virgin Olive Pomace: A Promising New By-Product from Pomace Extraction Process

At present the olive oil industry produces large amounts of secondary products once considered waste or by-products. In this paper, we present, for the first time, a new interesting olive by-product named “dried destoned virgin olive pomace” (DDVOP), produced by the pomace oil industry. The production of DDVOP is possible thanks to the use of a new system that differs from the traditional ones by having the dryer set at a lower temperature value, 350 °C instead of 550 °C, and by avoiding the solvent extraction phase. In order to evaluate if DDVOP may be suitable as a new innovative feeding integrator for animal feed, its chemical characteristics were investigated. Results demonstrated that DDVOP is a good source of raw protein and precious fiber; that it is consistent in total phenols (6156 mg/kg); rich in oleic (72.29%), linoleic (8.37%) acids and tocopherols (8.80 mg/kg). A feeding trial was, therefore, carried out on sheep with the scope of investigating the influence of the diet on the quality of milk obtained from sheep fed with DDVOP-enriched feed. The resulting milk was enriched in polyunsaturated (0.21%) and unsaturated (2.42%) fatty acids; and had increased levels of phenols (10.35 mg/kg) and tocopherols (1.03 mg/kg).