Food authentication of commercially-relevant shrimp and prawn species: From classical methods to Foodomics

Although seafood species identification has traditionally relied on morphological analysis, sometimes this is difficult to apply for the differentiation among penaeid shrimps owing to their phenotypic similarities and to the frequent removal of external carapace during processing. The objective of this review is to provide an updated and extensive overview on the molecular methods for shrimp and prawn species authentication, in which several omics approaches based on protein and DNA analysis are described. DNA-based methods include the amplification by PCR of different genes, commonly the mitochondrial 16S ribosomal RNA and cytochrome oxidase I genes. A recently described method based on RFLP coupled to PCR turned out to be particularly interesting for species differentiation and origin identification. Protein analysis methods for the characterization and detection of species-specific peptides are also summarized, emphasizing some novel proteomics-based approaches, such as phyloproteomics, peptide fragmentation, and species-specific peptide detection by HPLC coupled to multiple reaction monitoring (MRM) MS, the latter representing the fastest method described to date for species authentication in food.     

Formation of Schiff bases of O-phosphorylethanolamine and O-phospho-D,L-serine with pyridoxal 5'-phosphate. experimental and theoretical studies

Pyridoxal 5'-phosphate (PLP) is a B(6) vitamer acting as an enzyme cofactor in various reactions of aminoacid metabolism and inhibiting glycation of biomolecules. Nonenzymatic glycation of aminophospholipids alters the stability of lipid bilayers and cell function as a result. Similarly to protein glycation, aminophospholipid glycation initially involves the formation of a Schiff base. In this work, we studied the formation of Schiff bases between PLP and two compounds mimicking the polar head of natural aminophospholipids, namely: O-phosphorylethanolamine and O-phospho-D,L-serine. Based on the results, the pH-dependence of the microscopic constants of the two PLP-aminophosphate systems studied is identical with that for PLP-aminoacid systems. However, the rate and equilibrium formation constants for the Schiff bases of the aminophosphates are low relative to those for the aminoacids. A theoretical study by density functional theory of the formation mechanism for the Schiff bases of PLP with the two aminophospholipid analogues confirmed that the activation energy of formation of the Schiff bases is greater with aminophosphates; on the other hand, that of hydrolysis is essentially similar with aminoacids and aminophosphates.     

Surface barrier detector device and its application to alpha spectroscopy

A simple process was utilized to build a surface barrier detector which was applied to measure activities of uranium isotopes in a thin source prepared by electrolysis.     

High order finite volume schemes based on reconstruction of states for solving hyperbolic systems with nonconservative products. Applications to shallow-water systems

This paper is concerned with the development of high order methods for the numerical approximation of one-dimensional nonconservative hyperbolic systems. In particular, we are interested in high order extensions of the generalized Roe methods introduced by I. Toumi in 1992, based on WENO reconstruction of states. We also investigate the well-balanced properties of the resulting schemes. Finally, we will focus on applications to shallow-water systems.

     

Crystal and molecular structure of the inclusion compound between 1,1′-binaphthyl-2,2′-dicarboxylic acid and acetylacetone (1∶1)

The lattice type crystalline inclusion compound of 1,1-binaphthyl-2,2-dicarboxylic acid (BNDA) with acetylacetone (AcAc) 11 has been investigated by single crystal X-ray diffraction. AcAc is present as the enolic tautomer, stabilized by a notably short intramolecular hydrogen bond. This H-bond closes a six-membered ring with delocalization of the system of conjugated double bonds. In the crystal the AcAc molecules are incorporated into channels, delimited by bulky binaphyl moieties, in a hydrogen-bonded framework of BNDA, and they do not show any disorder. The strictly stoichiometric host:guest ratio seems to be enforced by packing forces only.