Giuseppe E. De Benedetto

Dispersal Patterns of Coastal Fish: Implications for Designing Networks of Marine Protected Areas

Information about dispersal scales of fish at various life history stages is critical for successful design of networks of marine protected areas, but is lacking for most species and regions. Otolith chemistry provides an opportunity to investigate dispersal patterns at a number of life history stages. Our aim was to assess patterns of larval and post-settlement (i.e. between settlement and recruitment) dispersal at two different spatial scales in a Mediterranean coastal fish (i.e. white sea bream, Diplodus sargus sargus) using otolith chemistry. At a large spatial scale (∼200 km) we investigated natal origin of fish and at a smaller scale (∼30 km) we assessed “site fidelity” (i.e. post-settlement dispersal until recruitment). Larvae dispersed from three spawning areas, and a single spawning area supplied post-settlers (proxy of larval supply) to sites spread from 100 to 200 km of coastline. Post-settlement dispersal occurred within the scale examined of ∼30 km, although about a third of post-settlers were recruits in the same sites where they settled. Connectivity was recorded both from a MPA to unprotected areas and vice versa. The approach adopted in the present study provides some of the first quantitative evidence of dispersal at both larval and post-settlement stages of a key species in Mediterranean rocky reefs. Similar data taken from a number of species are needed to effectively design both single marine protected areas and networks of marine protected areas.

Solid-phase microextraction-gas chromatography mass spectrometry and multivariate analysis for the characterization of roasted coffees.

HS-SPME-GC-MS in combination with PCA was employed to discriminate different arabica/robusta blends having different geographical origins. HS-SPME confirmed to be an effective and reproducible sampling technique for routine characterization of coffees. In addition, the chemometric approach permitted to find parameters suitable for the differentiation of the different blends and the determination of the real quality of the products. Finally, the proposed methods have been successfully applied to some commercial coffee blends.

A rapid and simple method for the determination of 3,4-dihydroxyphenylacetic acid, norepinephrine, dopamine, and serotonin in mouse brain homogenate by HPLC with fluorimetric detection.

A fast and simple isocratic high-performance liquid chromatography method for the determination of 3,4-dihydroxyphenylacetic acid (DOPAC), norepinephrine (NE), dopamine (DA), and serotonin (5-HT) in homogenate samples of mouse striatum employing the direct fluorescence of the neurotransmitters is described. The method has been optimized and validated. The analytes were separated in 15min on a reversed-phase column (C18) with acetate buffer (pH 4.0, 12mM)-methanol (86:14, v/v) as mobile phase; the flow rate was 1ml/min. The fluorescence measurements were carried out at 320nm with excitation at 279nm. The calibration curve for DA was linear up to about 2.5μg/ml, with a coefficient of determination (r(2)) of 0.9995 with a lower limit of quantification of 0.031μg/ml. Since the procedure does not involve sample pre-purification or derivatisation, the recovery ranged from 97% to 102% and relative standard deviation (RSD) was better than 2.9%, the use of the internal standard is not mandatory, further simplifying the method. Similar performance was obtained for the other analytes. As a result, thanks to its simplicity, rapidity and adequate working range, the method can be used for the determination of 3,4-dihydroxyphenylacetic acid, dopamine, norepinephrine and serotonin in animal tissues. An experimental 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson-like disease has been used to demonstrate the method is fit-for-purpose.

Determination of glycoalkaloids and relative aglycones by nonaqueous capillary electrophoresis coupled with electrospray ionization-ion trap mass spectrometry

Glycoalkaloids are naturally occurring nitrogen‐containing compounds present in many species of the family Solanaceae, including cultivated and wild potatoes (Solanum spp.), tomatoes (Lycopersicon spp.), etc. These compounds have pharmacological and toxicological effects on humans due to their significant anticholinesterase activity and disruption of cell membranes. Herein is reported the development of a capillary electrophoresis (CE) method using nonaqueous (NA) separation solutions in combination with ion trap mass spectrometry (MS and MS/MS) detection for the identification and quantification of glycoalkaloids and their relative aglycones. A mixture 90:10 v/v of MeCN‐MeOH containing 50 mM ammonium acetate and 1.2 M acetic acid (applied voltage of 25.5 kV) was selected as a good compromise for the separation and detection of these compounds. The electrospray MS measurements were carried out in the positive ionization mode using a coaxial sheath liquid, methanol‐water (1:1) with 1% of acetic acid at a flow rate of 2.5 νL/min. Under optimized experimental conditions, the predominant ion was the protonated molecular ion ([M+H]+) of solanidine (m/z = 398), tomatidine (m/z = 416), chaconine (m/z = 852), solanine (m/z = 868), and tomatine (m/z = 1034). MS/MS experiments were carried out systematically by changing the relative collisional energy and monitoring the intensities of the fragment ions that were not high enough to allow better quantification than with the mother ions. The method was used for analyzing glycoalkaloids in potato extracts.

Assessment of riboflavin and flavin content in common food samples by capillary electrophoresis with laser-induced fluorescence detection

To routinely assay the flavin contents in foodstuffs, a rapid and sensitive method was developed, in which the powerful separation capabilities of high-performance capillary electrophoresis (CE) were exploited. The method is based on a simple sample preparation, electrophoretic separation and laser induced fluorescence (LIF) detection. The average content of water-soluble riboflavin vitamers in raw natural products (i.e. vegetables, wheat flours and tomatoes) and bakers yeasts was evaluated without interferences from the sample matrices. Such an accurate and highly sensitive CE-LIF technique represents a significant improvement over previous analytical methods in terms of sensitivity, simplicity and efficiency. Indeed, it is well suited to satisfy the demands for accurate and sensitive detection with minimal sample preparation and clean-up.

A conserved role for the mitochondrial citrate transporter Sea/SLC25A1 in the maintenance of chromosome integrity

Histone acetylation plays essential roles in cell cycle progression, DNA repair, gene expression and silencing. Although the knowledge regarding the roles of acetylation of histone lysine residues is rapidly growing, very little is known about the biochemical pathways providing the nucleus with metabolites necessary for physiological chromatin acetylation. Here, we show that mutations in the scheggia (sea)-encoded Sea protein, the Drosophila ortholog of the human mitochondrial citrate carrier Solute carrier 25 A1 (SLC25A1), impair citrate transport from mitochondria to the cytosol. Interestingly, inhibition of sea expression results in extensive chromosome breakage in mitotic cells and induces an ATR-dependent cell cycle arrest associated with a dramatic reduction of global histone acetylation. Notably, loss of SLC25A1 in short interfering RNA (siRNA)-treated human primary fibroblasts also leads to chromosome breaks and histone acetylation defects, suggesting an evolutionary conserved role for Sea/SLC25A1 in the regulation of chromosome integrity. This study therefore provides an intriguing and unexpected link between intermediary metabolism and epigenetic control of genome stability.

Analysis by X-ray photoelectron spectroscopy of ruthenium stabilised polynuclear hexacyanometallate film electrodes

Abstract The role and effects of ruthenium on the electrochemical stabilisation of some metal-hexacyanometallate film electrodes was investigated by X-ray photoelectron spectroscopy (XPS). The following inorganic films were studied, cobalt(II)-hexacyanoferrate(II/III) (CoHCFe), nickel(II)-hexacyanoferrate(II/III) (NiHCFe), and iron(II/III)-hexacyanorutenate(II/III) (FeHCRu), and their corresponding ruthenium stabilised ones, Ru-CoHCFe, Ru-NiHCFe and Ru-FeHCRu. A mass increase of CoHCFe, NiHCFe, and FeHCRu, during continuous redox cycles (75–90 times) in a millimolar solution of RuCl3, was monitored by an electrochemical quartz crystal microbalance. Detailed XPS analysis of C 1s, O 1s, Fe 2p, Ni 2p, Co 2p, and Ru 3d peaks has allowed a comprehensive description of changes that occurred. The results obtained demonstrate that the insertion of ruthenium oxo species (e.g., Ru2O63+) was effective for the increase in lifetimes and for the electrocatalytic properties of ruthenium-modified metal-hexacyanometallate film electrodes. Three possible models of stabilisation are discussed.

Portable gliadin-immunochip for contamination control on the food production chain

Celiac disease (CD) is one of the most common digestive disorders caused by an abnormal immune reaction to gluten. So far there are no available therapies, the only solution is a strict gluten-free diet, which however could be very challenging as gluten can be hidden in many food products. Furthermore an additional problem is related to cross-contamination of nominal gluten-free foods with gluten-based ones during manufacturing. Here we propose a lab on chip platform as a powerful tool to help food manufacturers to evaluate the real amount of gluten in their products by an accurate in-situ control of the production chain and maybe to specify the real gluten content in packages labeling. Our portable gliadin-immunochips, based on an electrochemical impedance spectroscopy transduction method, were first calibrated and then validated for both liquid and solid food matrixes by analyzing different beers and flours. The high specificity of our assay was also demonstrated by performing control experiments on rice and potatoes flours containing prolamin-like proteins. We achieved limit of quantification of 0.5 ppm for gliadin that is 20 times lower than the worldwide limit established for gluten-free food while the method of analysis is faster and cheaper than currently employed ELISA-based methods. Moreover our results on food samples were validated through a mass spectrometry standard analysis.

A multianalytical study of archaeological faience from the Vesuvian area as a valid tool to investigate provenance and technological features

The investigation was aimed at defining the compositional and structural characteristics of a group of monochrome blue faiences recovered in Pompeii to assess provenance on the basis of their technological features. Different complementary analytical techniques were used: Scanning Electron Microscopy (SEM) to investigate the morphological aspects of the samples and in particular of the interfaces, micro-Raman Spectroscopy and XRPD to identify crystalline phases and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to assess the elemental composition due to its sensitivity to a wide range of elements and the adequate lateral resolution. Statistical data treatment of the elemental concentrations of both the ceramic bodies and the glazes allowed us to classify the objects into compositional groups and to verify the previously established archaeological hypothesis suggesting an Egyptian provenance for faience of Pompeii.

A new CE-ESI-MS method for the detection of stable hemoglobin acetaldehyde adducts, potential biomarkers of alcohol abuse

A new CE‐ESI‐MS method was developed to provide a simple way to study changes to hemoglobin (HbA) induced by acetaldehyde (Ach) in vitro. Instrumental parameters were univariately optimized in order to maximize the sensitivity of the CE‐ESI‐MS method. The electrophoretic separations were carried out in poly‐E323‐coated capillaries using 60 mM formic acid raised to pH 3.0 with ammonia and containing 5% 2‐propanol while the sheath liquid, 2‐propanol/water (30:70) with 0.1% formic acid, was delivered at 1.0 μL/min through a coaxial sheath flow electrospray interface. The HbA was incubated with Ach for intervals up to 24 h at concentration varying in the window 0.2–20 mM. Four stable Ach‐hemoglobin adducts in the hemoglobin tryptic digest were observed at the submillimolar Ach concentration and characterized by MS/MS experiments: although the α and β N‐amino terminal modifications were expected, the two internal ones arising, respectively, from the condensation of Ach molecules on the histidine residue in position 4 in α4 (i.e. the fourth peptide after tryptic digestion of alpha chain starting from amino terminal) and on the asparagine residue in position 2 in β3, were identified for the first time. During the in vitro experiments higher concentrations of Ach were also used; however, it was not possible to identify any other stable modification of hemoglobin. Interestingly, those stable modifications are the only ones in vivo identified in the hemoglobin of moderate alcohol drinkers.