Elemental characterization of bread and durum wheat by instrumental neutron activation analysis

Cereals are by far the most significant agricultural crops, not only due to the sheer amount of their gross-tonnage production and prevalence in human diets worldwide, but also as food vehicles of important items for human nutrition and wellness at large—proteins, dietary fibers and oligoelements, such as selenium, calcium, zinc and iron, to name just a few. Still, some micronutrients feature an uneven distribution in the upper continental crust, and thus in cultivation soils deriving therefrom. Whether soils have always been poor in an essential element, or have just become deprived of it by intensive farming, the result is the same: insufficient soil–plant transfer, feeble-to-nonexistent plant uptake, and, therefore, unsatisfactory dietary distribution of that element through the food chain. Countries that implemented corrective measures or programs of crop biofortification and consumer education have been successful in dealing with some micronutrients’ deficiencies. Given their relative weight in Portuguese diets, cereals are obvious candidates for crop-supplementation strategies that may contribute to an upgrade in the health status of the whole population. A good knowledge of element-baseline data for major cereal varieties (plants) and main production areas (soils) is a pre-requisite though. The present work was aimed at an elemental characterization of cereals and soils from relevant wheat-producing areas of mainland Portugal. This paper is focused on wheat samples—bread and durum wheats; Triticum aestivum L. (Farak and Jordão cultivars) and Triticum durum Desf. (Don Duro and Simeto cultivars), respectively—from the 2009 campaign, collected at Trás-os-Montes, Alto Alentejo and Baixo Alentejo (inland regions). Elemental concentrations were determined by instrumental neutron activation analysis (INAA; k ₀-variant), and assessed with the k ₀-IAEA software. Quality control was asserted through the analysis of NIST-SRM^® 1567a (Wheat Flour), NIST-SRM^® 1568a (Rice Flour) and GBW 07404 (Limy-yellow Soil). Results are discussed and compared to available data from abroad.     

Characterization of dextrin hydrogels by FTIR spectroscopy and solid state NMR spectroscopy

Fourier transform infrared (FTIR) and ¹³C solid state nuclear magnetic resonance (NMR) spectroscopy were used to study dextrin structural changes occurring upon hydrogel formation by vinyl acrylate (VA) grafting and subsequent free radical polymerization. The degrees of VA substitution (DS) and polymerization (DP) were quantified up to 40%VA by FTIR intensity measurements and partial least squares (PLS)/FTIR, the latter being a faster and less error-prone method. Above 40%VA, both parameters are underestimated by FTIR. A spin counting NMR experiment showed high carbon observabilities for hydrogels and improved PLS/NMR models were achieved for DS and DP determination. Alternative NMR integration methods are hindered by the broad VA peaks and need for area correction, due to their CP dynamics. NMR changes in C1 profile showed that a single helical conformation predominates at lower %VA, being replaced by disordered conformations as %VA increases. Furthermore, a correlation FTIR/NMR study indicated that ring conformations are significantly affected in hydrogels, compared to unpolymerized dextrin.     

Report of in vitro antileishmanial properties of Iberian macroalgae

Here is reported the anti Leishmania infantum activity of 48 hexane, CH₂Cl₂ and MeOH extracts from 16 macroalgae collected on the Iberian Coast. Seven hexane and CH₂Cl₂ Cystoseira baccata, Cystoseira barbata, Cystoseira tamariscifolia, Cystoseira usneoides, Dictyota spiralis and Plocamium cartilagineum extracts were active towards promastigotes (IC₅₀ 29.8–101.8 μg/mL) inducing strong morphological alterations in the parasites. Hexane extracts of C. baccata and C. barbata were also active against intracellular amastigotes (IC₅₀ 5.1 and 6.8 μg/mL, respectively). Fatty acids, triacylglycerols, carotenoids, steroids and meroterpenoids were detected by nuclear magnetic resonance (NMR), and gas chromatography in the Cystoseira extracts. These results suggest that Cystoseira macroalgae contain compounds with antileishmanial activity, which could be explored as scaffolds to the development of novel sources of antiparasitic derivatives.     

Evaluation of the Structure–Activity Relationship of Rifabutin and Analogs: A Drug–Membrane Study

This work focuses on the influence of rifabutin and two novel analogs, namely, N′‐acetyl‐rifabutin and N′‐butanoyl‐rifabutin, on the biophysical properties of lipid membranes. Monolayers and multilamellar vesicles composed of egg L ‐α‐phosphatidylcholine:cholesterol in a molar ratio of 4:1 are chosen to mimic biological membranes. Several accurate biophysical techniques are used to establish a putative relationship between the chemical structure of the antimycobacterial compounds and their activity on the membranes. A combination of in situ experimental techniques, such as Langmuir isotherms, Brewster angle microscopy, polarization‐modulated infrared reflection–absorption spectroscopy, and small‐angle X‐ray scattering, is used to assess the drug–membrane interaction. A relationship between the effect of a drug on the organization of the membranes and their chemical structure is found and may be useful in the development of new drugs with higher efficacy and fewer toxic effects.     

Charge and substituent effects on the stability of porphyrin/G-quadruplex adducts

The adduct ions of two tetramolecular G-quadruplexes formed from the d(TGGGGT) and d(TTGGGGGT) single strands with a group of cationic porphyrins, with different charges and substituents, and one neutral porphyrin, were investigated by ESI-MS and ESI-MS/MS in the negative ion mode. Formation of [Q + nNH(4)(+)+P(p+)-(z + n + p)H(+)](z-) adduct ions (where Q = quadruplex, n = number of quartets minus 1, P = porphyrin and p(+) = 0,1,2,3,4) indicates that the porphyrins are bound outside the quadruplexes providing an additional stabilization to those structures. The fragmentation pathways of the [Q + nNH(4)(+)+P(p+)-(z + n + p)H(+)](z-) adduct ions depend on the number of positive charges (p(+)) of the porphyrins and on the overall complex charge (z(-)), but do not show a significant dependence on the type of the substituent groups in the porphyrins. Formation of the 'unfilled' ions [Q + P(p+)-(z + p)H(+)](z-) predominates for porphyrins with a higher number of positive charges. Strand separation with the formation of [T + P(p+)-(z-2 + p)H(+)]((z-2)-) and (SS-2H(+))(2-) ions, where T = [d(TG(4)T)](3) and [d(T(2)G(5)T)](3) and SS = d(TG(4)T) and d(T(2)G(5)T) is only observed for the complexes with a higher overall negative charge. Porphyrin loss with the formation of [Q + nNH(4)(+)-(z + n)H(+)](z-) ions occurs predominantly for the neutral and monocharged porphyrins. The predominant formation of the 'unfilled' ions, [Q + P(p+)-(z + n)H(+)](z-), for porphyrins with a higher number of charges shows that these porphyrins can prevent strand separation and preserve, at least partially, the quadruplex structure.     

Regularity for Eigenfunctions of Schr?dinger Operators

We prove a regularity result in weighted Sobolev (or Babu?ka?CKondratiev) spaces for the eigenfunctions of certain Schr?dinger-type operators. Our results apply, in particular, to a non-relativistic Schr?dinger operator of an N-electron atom in the fixed nucleus approximation. More precisely, let ${\mathcal{K}_{a}^{m}(\mathbb{R}^{3N},r_S)}$ be the weighted Sobolev space obtained by blowing up the set of singular points of the potential ${V(x) = \sum_{1 \le j \le N} \frac{b_j}{|x_j|} + \sum_{1 \le i < j \le N} \frac{c_{ij}}{|x_i-x_j|}}$ , ${x \in \mathbb{R}^{3N}}$ , ${b_j, c_{ij} \in \mathbb{R}}$ . If ${u \in L^2(\mathbb{R}^{3N})}$ satisfies ${(-\Delta + V) u = \lambda u}$ in distribution sense, then ${u \in \mathcal{K}_{a}^{m}}$ for all ${m \in \mathbb{Z}_+}$ and all a ?? 0. Our result extends to the case when b _j and c _ij are suitable bounded functions on the blown-up space. In the single-electron, multi-nuclei case, we obtain the same result for all a?<?3/2.     

Re-exploring the high-throughput potential of microextraction techniques,SPME and MEPS,as powerful strategies for medical diagnostic purposes. Innovative approaches,recent applications and future trends

The human population continues to grow exponentially in the fast developing and most populated countries, whereas in Western Europe it is getting older and older each year. This inevitably raises the demand for better and more efficient medical services without increasing the economic burden in the same proportion. To meet these requirements, improvement of medical diagnosis is certainly a key aspect to consider. Therefore, we need powerful analytical methodologies able to go deeper and further in the characterization of human metabolism and identification of disease biomarkers and endogenous molecules in body fluids and tissues. The ultimate goal is to have a reliable and early medical diagnosis, mitigating the disease complications as much as possible. Microextraction techniques (METs) represent a key step in these analytical methodologies by providing samples in the suitable volumes and purification levels necessary for the characterization of the target analytes. In this aspect, solid-phase microextraction (SPME) and, more recently, microextraction by packed sorbent (MEPS), are powerful sample preparation techniques, characterized by their reduced time of analysis, low solvent consumption, and broad application. Moreover, as miniaturized techniques, they can be easily automatized to have a high-throughput performance in the clinical environment. In this review, we explore some of the most interesting MEPS and SPME applications, focusing on recent trends and applications to medical diagnostic, particularly the in vivo and near real time applications.

Natural Compounds against Alzheimer’s Disease: Molecular Recognition of Aβ1–42 Peptide by Salvia sclareoides Extract and its Major Component,Rosmarinic Acid,as Investigated by NMR

Amyloid peptides, Aβ1–40 and Aβ1–42, represent major molecular targets to develop potential drugs and diagnostic tools for Alzheimer’s Disease (AD). In fact, oligomeric and fibrillar aggregates generated by these peptides are amongst the principal components of amyloid plaques found post mortem in patients suffering from AD. Rosmarinic acid has been demonstrated to be effective in preventing the aggregation of amyloid peptides in vitro and to delay the progression of the disease in animal models. Nevertheless, no information is available about its molecular mechanism of action. Herein, we report the NMR characterization of the interaction of Salvia sclareoides extract and that of its major component, rosmarinic acid, with Aβ1–42 peptide, whose oligomers have been described as the most toxic Aβ species in vivo. Our data shed light on the structural determinants of rosmarinic acid–Aβ1–42 oligomers interaction, thus allowing the elucidation of its mechanism of action. They also provide important information for the rational design of new compounds with higher affinity for Aβ peptides to generate new anti‐amyloidogenic molecules and/or molecular tools for the specific targeting of amyloid aggregates in vivo. In addition, we identified methyl caffeate, another natural compound present in different plants and human diet, as a good ligand of Aβ1–42 oligomers, which also shows anti‐amyloidogenic activity. Finally, we demonstrated the possibility to exploit STD‐NMR and trNOESY experiments to screen extracts from natural sources for the presence of Aβ peptide ligands.     

Heptyl α‐D‐Mannosides Grafted on a β‐Cyclodextrin Core To Interfere with Escherichia coli Adhesion: An In Vivo Multivalent Effect

n‐Heptyl α‐D ‐mannoside (HM) has previously been identified as a nanomolar FimH antagonist able to prevent Escherichia coli adhesion. We have designed mono‐ and heptavalent glycoconjugates in which HM is tethered to β‐cyclodextrin (β‐CD) through short and long spacers. One‐pot click or co‐clicking procedures were developed to directly obtain the glycoconjugates from unprotected HM and β‐CD precursors. These FimH antagonists were examined biophysically and in vivo. Reverse titrations by isothermal calorimetry led to trapping of the short‐tethered heptavalent β‐CD in a complex with three FimH lectins. Combined dynamic light scattering and small‐angle X‐ray solution scattering data allowed the construction of a model of the FimH trimer. The heptavalent β‐CDs were shown to capture and aggregate living bacteria in solution and are therefore also able to aggregate FimH when attached to different bacteria pili. The first in vivo evaluation of multivalent FimH inhibitors has been performed. The heptavalent β‐CDs proved to be much more effective anti‐adhesive agents than monovalent references with doses of around 2 μg instilled in the mouse bladder leading to a significantly decreased E. coli load. Intravenously injected radiolabeled glycoconjugates can rapidly reach the mouse bladder and >2 μg concentrations can easily be retained over 24 h to prevent fluxing bacteria from rebinding.     

Genotyping of Saccharomyces cerevisiae strains by interdelta sequence typing using automated microfluidics

Amplification of genomic sequences flanked by delta elements of retrotransposons TY1 and TY2 is a reliable method for characterization of Saccharomyces cerevisiae strains. The aim of this study is to evaluate the usefulness of microfluidic electrophoresis (Caliper LabChip) to assess the factors that affect interlaboratory reproducibility of interdelta sequence typing for S. cerevisiae strain delimitation. We carried out experiments in two laboratories, using varying combinations of Taq DNA polymerases and thermal cyclers. The reproducibility of the technique is evaluated using non-parametric statistical tests and we show that the source of Taq DNA polymerase and technical differences between laboratories have the highest impact on reproducibility, whereas thermal cyclers have little impact. We also show that the comparative analysis of interdelta patterns is more reliable when fragment sizes are compared than when absolute and relative DNA concentrations of each band are considered. Interdelta analysis based on a smaller fraction of bands with intermediate sizes between 100 and 1000 bp yields the highest reproducibility.