Application of a voltammetric electronic tongue and near infrared spectroscopy for a rapid umami taste assessment

The relationships between sensory attribute and analytical measurements, performed by electronic tongue (ET) and near-infrared spectroscopy (NIRS), were investigated in order to develop a rapid method for the assessment of umami taste. Commercially available umami products and some aminoacids were submitted to sensory analysis. Results were analysed in comparison with the outcomes of analytical measurements. Multivariate exploratory analysis was performed by principal component analysis (PCA). Calibration models for prediction of the umami taste on the basis of ET and NIR signals were obtained using partial least squares (PLS) regression. Different approaches for merging data from the two different analytical instruments were considered. Both of the techniques demonstrated to provide information related with umami taste. In particular, ET signals showed the higher correlation with umami attribute. Data fusion was found to be slightly beneficial - not so significantly as to justify the coupled use of the two analytical techniques

CD69 molecule in human neutrophils: its expression and role in signal trasducing mechanisms

The CD69 glycoprotein is an early activation antigen of T and B lymphocytes and it is constitutively expressed on thymocytes and platelets. Here we report its presence on neutrophils and on bone marrow-derived myeloid precursors. Indeed, promyelocytic cells are CD69+ on the cell membrane, while in resting neutrophils this molecule is located inside the cell. However, intracellular CD69 molecules are rapidly mobilized to the cell surface upon activation by PMA or fMLP. This translocation is independent on a new protein synthesis, as it is not inhibited by cycloheximide; furthermore, CD69 molecules are likely stored in a trans-Golgi structure since their expression is not affected by brefeldin A, a drug that blocks molecular trafficking from ER to Golgi vesicles. Immunoprecipitation of CD69 molecules either from activated neutrophils or from bone marrow cells showed that this protein has the same molecular size (28-34 kDa) as observed in platelets, T and B lymphocytes, and thymocytes. This similarity is reflected also in the functional role played by this molecule: in neutrophils as well as in lymphocytes and platelets, CD69 stimulation induced Ca2+ influx through cellular membrane; furthermore, the perturbation of the CD69 antigen on PMA-activated neutrophils enhances the lysozyme release, suggesting a role of this molecule in the regulation of granule exocytosis, probably through a Ca(2+)-dependent mechanism