La Diagnostica nei Beni Culturali- Moderni Metodi di Indagine

Vengono descritte le moderne metodologie di indagine nel settore dei beni culturali. Di esse vengono descritte le caratteristiche essenziali, in modo semplice le basi teoriche e infine le applicazioni di cui vengono forniti esempi specifici

One- and two-dimensional NMR studies of plasmalogens (alk- l -enyl-phosphatidylethanolamine)

9 pages, 8 figures, 3 tables1H and 13C nuclear magnetic resonance (NMR) spectra of phosphatidylethanolamine plasmalogen were studied. Resonances in both spectra were assigned by conventional one- and two-dimensional NMR techniques. Distinctive signals corresponding to the olefinic carbons near the vinyl ether group were shown to be the most useful in both qualitative and quantitative analysis. The plasmalogen content in different fish lipid samples, as determined by 13C-NMR spectroscopy, was in good agreement with the data obtained by gas chromatograpy.We acknowledge the financial support for Research Project ALI 90-773 provided by the Comisión Interministerial de Ciencia y Tecnología (CICYT), the Research Project CEE UP.2.571 (of DG XIV), and a research grant from the Departamento de Postgrado (CSIC) to I.M.Peer reviewe

Identificazione di sostanze organiche in bottiglie di vetro rinvenute negli scavi archeologici di pompei

Atti del convegno- De Frede editor

SYNTHETIC AMATOXIN ANALOGS .2. A PROTON NMR-STUDY OF S-DEOXO-ILE3-(L)ALA5 AND S-DEOXO-ILE3-(D)ALA5-AMANINAMIDE

Amatoxin analogues with d and l-Ala substitutions in position 5 have been studied by means of 1- and 2-dimensional n.m.r. spectroscopy at 500 MHz. The assignment of all resonances for both analogues has been carried out mostly with the use of COSY and NOESY type experiments. Temperature coefficients for the amide NH protons have been measured and the data compared to known amatoxin structures. The results obtained demonstrate that the rigidity of the bicyclic amatoxin framework is preserved in the d and l-Ala5 analogues, although the temperature coefficients point to intramolecular hydrogen bonds stronger in the case of the l-Ala analogue. The 10-fold decrease of biological activity is discussed in terms of structural features involving also the Trp4 indole accessibility

HETERODETIC BICYCLIC DECAPEPTIDE CYCLO(GLU1-LEU2-PRO3-GLY4-SER5-ILE6-PRO7-ALA8)CYCLO-(1-GAMMA-5-BETA)PHE9-GLY10 - SYNTHESIS AND 2-D NMR CONFORMATIONAL-ANALYSIS

Bicyclic peptides are useful model molecules that can mimic the constrained local folding of a great number of natural peptides and proteins, such as ionophoric peptides, enzyme active site, and ligand-receptor active site. The synthesis of the bicyclic title compound with the liquid phase method is described with experimental details. Of particular interest is the heterodetic closure of the second ring. The peptide showed a complexing activity with metal cations like Ba2+, Ca2+, and Mg2+. The free bicyclic peptide conformation in solution has been studied by means of NMR spectroscopy and a plausible structure model worked out with model building on NMR constraints is propose

Experimental evidence for the interaction of clupeine YI with mononucleotides.

1H NMR evidence of a preferential interaction between mononucleotides and a protamine fraction (clupeine YI) is presented. The NMR data demonstrate that clupeine YI interacts strongly with a purine mononucleotide but only weakly with a pyrimidine nucleotide. The biol. implications of these results are discussed