Kinetics of the adsorption of bovine serum albumin contained in a model wine solution by non-swelling ion-exchange resins

Adsorption of wine proteins is an essential step in the production of white and rosé wines. In order to develop environmentally friendly adsorption processes, non-swelling adsorbents are required. The performance of selected non-swelling ion-exchange resins (Macro-Prep™ 50S and Streamline® SP) was studied by describing the process kinetics of the adsorption of BSA in a model wine solution. The process was assumed to be diffusion controlled and a shrinking core model was applied. Experiments were performed in the 5–35°C temperature range and with different equilibrium partition coefficients. The results obtained with the shrinking core model were theoretically consistent and the apparent diffusivity values correlated very well with theoretically estimated effective diffusivities combined with a linear dependence of porosity with temperature. Separating the temperature effect on porosity, the apparent diffusivity followed an Arrhenius type dependency with temperature with 16.9 kJ/mole activation energy

Neurofibromatosis type 1 gene product (neurofibromin) associates with microtubules

The neurofibromatosis type 1 (NF1) gene was recently identified by positional cloning and found to encode a protein with structural and functional homology to mammalian and yeast GTPase-activating proteins (GAPs). Using antibodies directed against the NF1 gene product, a protein of ∼250kDa was identified and termed neurofibromin. Double-indirect immunofluorescent labeling with anti-neurofibromin and anti-tubulin antibodies demonstrates that neurofibromin associates with cytoplasmic microtubules. Immunoblotting of microtubule-enriched cytoplasmic fractions, using antibodies generated against neurofibromin, shows that neurofibromin copurifies with microtubules. When portions of neurofibromin are expressed in Sf9 insect cells they associate with polymerized microtubules; furthermore, the critical residues for this interaction reside within the GAP-related domain of neurofibromin. The unexpected association of neurofibromin with microtubules suggests that neurofibromin is involved in microtubule-mediated intracellullar signal transduction pathways.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45544/1/11188_2005_Article_BF01233074.pd

Chemical and Sensory Characterization of DOC Red Wines from Marche (Italy) Related to Aging and Grape Cultivars

The DOC red wines Lacrima di Morro d’Alba, Rosso Conero, Rosso Piceno, Rosso Piceno Superiore, and Vernaccia di Serrapetrona are produced in the region of Marche (Central Italy) and have received little research attention. The characterization of monomeric polyphenols (HPLC-DAD), copigmentation parameters and tannin fractions (spectrophotometric essays), sugars, alcohols and organic acids (HPLC-RI), and colorimetric parameters (CIE) was performed on 30 samples obtained during three different vintages ranging from 1996 to 2000 (two replications for each year). The most significant components explaining the variability of the samples were the HPLC determinations, particularly malvidin-3-glucoside, glucose, and fructose. The bitterness and astringency of the wines were determined with panel tastings and all the collected data were analysed using principle component analysis and partial least squares methodologies. The extent to which the variance in these sensory measures could be explained by the phenolic compositon was determined. Wines obtained from the cultivars Lacrima di Morro and Vernaccia di Serrapetrona were statistically different from all other wines, which were obtained with different percentages of the cultivars Sangiovese and Montepulciano. Wines made from Lacrima were found to be statistically similar to a Spanish cultivar named Tintorera. Vernaccia wines were outliers because of the different processing of the grapes (it is a red, sweet sparkling wine). However, the influence of grape variety seemed to be more significant than wine-processing technology in distinguishing the wines by these chemical and sensory measures