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

He who dares only wins sometimes: physiological stress and contest behaviour in Xiphophorus helleri

While many factors influence contest outcome and social dominance in animals, there is increasing interest in behavioural-physiological stress-coping styles. Causality, however, is often ambiguous; is physiological state determined by contest outcome orvice versa? Furthermore, experimental protocols may themselves induce stress responses that impact individual behaviour and, thus, potentially contest outcome. Here we test whether latency to recover from acute stress, measured both physiologically and behaviourally, predicts who initiates and who wins dyadic contests between pairs of male green swordtails (Xiphophorous helleri). In line with our predictions, animals that recovered faster (behaviourally) from disturbance created by the experimental protocol prior to meeting an opponent were more likely to initiate contests; however, they were not more likely to win and, contrary to expectations, had higher pre-contest cortisol levels than their opponents. They also showed greater physiological stress responses to the experiment as determined from the difference between pre- and post-contest cortisol levels. Moreover, stress response was independent of whether a contest escalated. In contradiction to evidence found in other taxa and fish systems, the suite of traits that we measured were not correlated in a manner that allowed classification of the animals into the usual reactive and proactive stress-coping styles. Our results suggest that coping style may play a key role in determining which individual initiates a contest, but that other factors govern contest outcome.</jats:p

Controls on dryland mountain landscape development along the NW Saharan desert margin: Insights from Quaternary river terrace sequences (Dadès River, south-central High Atlas, Morocco)

This study documents river terraces from upstream reaches of the Dad es River, a major fluvial system draining the south-central High Atlas Mountains. Terraces occur as straths with bedrock bases positioned at 10 m altitudinal intervals up to 40 m (T1-T5) above the valley floor, becoming less common between 50 and 140 m. The rock strength, stratigraphy and structure of the mountain belt influences terrace distribution. Terraces are absent in river gorges of structurally thickened limestone; whilst welldeveloped, laterally continuous terraces (T1-T4) form along wide valleys occupying syncline structures dominated by weaker interbedded limestone-mudstone. Terrace staircases develop in confined canyons associated with weaker lithologies and influence from structural dip and stratigraphic configuration. Terraces comprise a bedrock erosion surface overlain by fluvial conglomerates, rare overbank sands and colluvium. This sequence with some OSL/IRSL age control, suggests terrace formation over a 100 ka climate cycle with valley floor aggradation during full glacials and incision during glacial-interglacial transitions. This integrates with other archives (e.g. lakes, glaciers, dunes), appearing typical of landscape development along the NW Saharan margin south of the High Atlas, and similar to patterns in the western-southern Mediterranean. The 100 ka climate cycle relationship suggests that the terrace sequence documents Late-Middle Pleistocene landscape development. Consistent altitudinal spacing of terraces and their distribution throughout the orogen suggests sustained base-level lowering linked to uplift-exhumation of the High Atlas. Low incision rates (<0.2 mm a 1) and general absence of terrace deformation suggests dominance of isostatically driven base-level lowering with relief generation being Early Pleistocene or older.National Geographic research grant (8609-09

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

Influence of intrinsic factors on conventional wine protein stability tests

The influence of intrinsic factors on the results of ethanol, tannin and heat tests, routinely used to assess wine protein stability, was studied. Experiments were performed on 23 Portuguese and Austrian wines. The factors considered were total protein content, pH, ethanol content and the amount of several relevant cations (calcium, iron, copper, sodium and potassium). The protein pro®les were analysed by HPLC fractionation. The heat test was a good indicator of total protein content while the ethanol and the tannin tests showed signi®cant interference by the other factors. A factorial design at two levels in selected samples was also performed to assess the influence of pH, storage temperature, tannin concentration and ethanol concentration on the development of turbidity. Results indicated that ethanol content had no significant infuence, and that pH and storage temperature had a significant infuence, though only when tannin was added

Archaeological collections from Long Hole (Gower, Swansea, UK) and their place in the British Palaeolithic

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