Modeling Neurotransmission: Computational Tools to Investigate Neurological Disorders

The investigation of synaptic functions remains one of the most fascinating challenges in the field of neuroscience and a large number of experimental methods have been tuned to dissect the mechanisms taking part in the neurotransmission process. Furthermore, the understanding of the insights of neurological disorders originating from alterations in neurotransmission often requires the development of (i) animal models of pathologies, (ii) invasive tools and (iii) targeted pharmacological approaches. In the last decades, additional tools to explore neurological diseases have been provided to the scientific community. A wide range of computational models in fact have been developed to explore the alterations of the mechanisms involved in neurotransmission following the emergence of neurological pathologies. Here, we review some of the advancements in the development of computational methods employed to investigate neuronal circuits with a particular focus on the application to the most diffuse neurological disorders.     

Piedmont olive oils: Compositional characterization and discrimination from oils from other regions

Piedmont olive oils collected in 2010 were characterized, for the first time, in terms of their fatty acid profile using GC and ¹H NMR and compared to other oils from five Italian regions. Applying NMR spectroscopy on the olive oil samples, without manipulation, it is possible to calculate the proportion of the different acyl groups in the oil samples. As the area of the signals is proportional to the number of each type of proton in the sample, saturated, monounsaturated (oleic acid) and polyunsaturated (linoleic and linolenic acids) fatty acids were determined. All analyzed samples can be categorized as virgin olive oil extra quality according to the oleic/linoleic ratio. Based on a preliminary geographical investigation, olive oils produced in the North of Italy show a good separation from those from Central and Southern regions. Practical applications : Oil characterization of new products is the basis for further nutritional and food technological investigations and the quality of edible oils is of great concern especially for products available on the market. The two adopted techniques show a remarkable agreement in the evaluation of fatty acid composition of oil samples. Also, this research, by means of ¹H NMR, provides information on geographical origin of the olive oils of Northern Italian regions with respect to Central and Southern regions.     

Correlation between isotopic and meteorological parameters in Italian wines: a local-scale approach

BACKGROUND: Since the beginning of the 1980s deuterium nuclear magnetic resonance and carbon‐13 mass spectrometry have proved to be reliable techniques for detecting adulteration and for classifying natural products by their geographic origin. Scientific literature has so far mainly focused on data acquired at regional level where isotopic parameters are correlated to climatic mean data relative to large territories. RESULTS: Nebbiolo and Barbera wine samples of various vintages and from different areas within the Piedmont region (northern Italy) were analysed using SNIF‐NMR and GC‐C‐IRMS and a large set of meteorological parameters were recorded by means of weather stations placed in fields where the grapes were grown. Correlations between isotopic (²H and ¹³C) data and several climatic parameters at a local level (mean temperature, total rainfall, mean humidity and thermal sums) were attempted and some linear correlations were found. CONCLUSIONS: Mean temperature and total rainfall were found to be correlated to isotopic (²H and ¹³C) abundance in linear direct and inverse proportions respectively. Lower or no correlations between deuterium and carbon‐13 abundances and other meteorological parameters such as mean humidity and thermal sums were found. Moreover, wines produced from different grape varieties in the same grape field showed significantly different isotopic values. Copyright © 2011 Society of Chemical Industry     

A Simulative Model for the Analysis of Conduction Properties of Ion Channels Based on First-Principle Approaches

A physical model and a simulation framework are proposed for the analysis of conduction properties of ion channels. The permeation path of ions along the channel is defined through the simultaneous occupancy of a set of individual ion binding sites within the pore identified from structural X-ray data and Molecular Dynamics (MD) simulations. All permitted elementary transitions between different channel configurations and their rate constants can be evaluated from the atomistic structure and MD data and are implemented into a statistical model which is then coded in a Monte Carlo simulator. Results for K ions permeating the KcsA channel are shown.     

Isotope Separation of Nitrogen by Ion Exchange Chromatography in a Cascade System

The ion exchange chromatography technique in a cascade process was used to separate stable isotopes of nitrogen (¹⁴N/¹⁵N). For this purpose, three column systems (with different internal diameters, S1?14.5 cm; S2–9.5 cm; S3–5.2 cm) were used that contained the cationic resins DOWEX 50 WX8 (as H⁺ and equilibrated with H₂O) and measured 1.7 m in height. Isotopic fractionation of nitrogen occurs during displacement band chromatography (DBC) of the NH₃ (aq) solution with a 0.75 mol L^?1 NaOH solution. The active sites of the resin were previously saturated to form NH₄ ⁺ (RNH₄) with a 0.75 mol L^?1 solution of (NH₄)₂SO₄ at a natural isotopic abundance (0.366 at. %) in ¹⁵N. The NH₄ ⁺/NH₃ (aq) equilibrium was determined during the DBC, which enriched the rear portion of the band with ¹⁵N. In S1, enrichment of approximately 5 at. % of ¹⁵N in the last 10 cm was achieved. After four interactions (couplings) between S1–S2, an enrichment of approximately 50 at. % of ¹⁵N was obtained. During the interaction between S2–S3, after the second coupling, an isotopic enrichment of approximately 90 at. % of ¹⁵N was observed, which produced 70 g month^?1 of (¹⁵NH₄)₂SO₄.     

Natural origin of ascorbic acid: Validation by C NMR and IRMS

A new method for the extraction and purification of ascorbic acid from two tropical fruits (acerola and camu-camu) is presented. ¹³C nuclear magnetic resonance and isotopic ratio mass spectroscopy (¹³C/¹²C) were used to recognize ascorbic acid coming from either natural or industrial sources. A quantitative ¹³C NMR procedure was optimized to calculate isotopic relative abundances on each molecular site; data were treated by a multivariate method.