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In order to contribute to the understanding of the origin of biaxial nematic ordering in tetrapodes, a deuterium NMR study was performed on mixtures of monomers from organosiloxane tetrapodes with a deuterated nematic probe. Contrary to the tetrapode system previously studied, which exhibits a biaxial nematic phase, the results for monomers are compatible, within the experimental error, with uniaxial nematic ordering in the whole nematic range. The data are in agreement with the conjecture that the nematic biaxial behaviour is related to hindering of the mesogenic units' rotational movements, arising from interdigitation and connection to the central silicon core.

The simultaneous separation and quantification of two casein peptides {(IPP}, {VPP)} presenting potent inhibitory activity of angiotensin-converting-enzyme {(ACE)} and casein in fermented milks was developed. Gradient elution was carried out at a flow-rate of 1 {mL/min}, using a mixture of two solvents. Solvent A was 0.1% {TFA} in water and solvent B was acetonitrile-water-trifluoracetic acid 95:5:0.1. The effluent was monitored by {UV} detector at 214 nm. Calibration curves were constructed in the interval of 0.01-1.0 {mg/mL} for {VPP}, 0.005-1.0 {mg/mL} for {IPP}, and 0.05-3.0 {mg/mL} for casein. R2 invariably exceeded 0.999. The detection limits were 0.004 for {VPP}, 0.002 {mg/mL} for {IPP}, and 0.02 {mg/mL} for casein. Repeatability of the method was evaluated by six consecutive injections of two standard solutions containing {VPP}, {IPP}, and casein. The {RSD} values for concentration were all below 5.08%. Recovery studies were carried out to determine the accuracy of the method. Recoveries ranged between 88 and 98.2%. The methodology was applied, not only, for the monitorization of {VPP}, {IPP}, and casein in commercial fermented milks labeled as presenting antihypertensive properties, but also, in milk with different degrees of fermentation by L. Helveticus, and in other commercial functional fermented milks, such as, those presenting cholesterol lowering properties.

The simultaneous separation and quantification of two casein peptides (IPP, VPP) presenting potent inhibitory activity of angiotensin-converting-enzyme (ACE) and casein in fermented milks was developed. Gradient elution was carried out at a flow-rate of 1 mL/min, using a mixture of two solvents. Solvent A was 0.1% TFA in water and solvent B was acetonitrile-water-trifluoracetic acid 95:5:0.1. The effluent was monitored by UV detector at 214 nm. Calibration curves were constructed in the interval of 0.01-1.0 mg/mL for VPP, 0.005-1.0 mg/mL for IPP, and 0.05-3.0 mg/mL for casein. R 2 invariably exceeded 0.999. The detection limits were 0.004 for VPP, 0.002 mg/mL for IPP, and 0.02 mg/mL for casein. Repeatability of the method was evaluated by six consecutive injections of two standard solutions containing VPP, IPP, and casein. The RSD values for concentration were all below 5.08%. Recovery studies were carried out to determine the accuracy of the method. Recoveries ranged between 88 and 98.2%. The methodology was applied, not only, for the monitorization of VPP, IPP, and casein in commercial fermented milks labeled as presenting anti hypertensive properties, but also, in milk with different degrees of fermentation by L Helveticus, and in other commercial functional fermented milks, such as, those presenting cholesterol lowering properties.

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Decameric vanadate species (V10) inhibit the rate and the extent of G-actin polymerization with an IC50 of 68+/-22 microM and 17+/-2 microM, respectively, whilst they induce F-actin depolymerization at a lower extent. On contrary, no effect on actin polymerization and depolymerization was detected for 2mM concentration of "metavanadate" solution that contains ortho and metavanadate species, as observed by combining kinetic with (51)V NMR spectroscopy studies. Although at 25 degrees C, decameric vanadate (10 microM) is unstable in the assay medium, and decomposes following a first-order kinetic, in the presence of G-actin (up to 8 microM), the half-life increases 5-fold (from 5 to 27 h). However, the addition of ATP (0.2mM) in the medium not only prevents the inhibition of G-actin polymerization by V10 but it also decreases the half-life of decomposition of decameric vanadate species from 27 to 10h. Decameric vanadate is also stabilized by the sarcoplasmic reticulum vesicles, which raise the half-life time from 5 to 18h whereas no effects were observed in the presence of phosphatidylcholine liposomes, myosin or G-actin alone. It is proposed that the "decavanadate" interaction with G-actin, favored by the G-actin polymerization, stabilizes decameric vanadate species and induces inhibition of G-actin polymerization. Decameric vanadate stabilization by cytoskeletal and transmembrane proteins can account, at least in part, for decavanadate toxicity reported in the evaluation of vanadium (V) effects in biological systems.

Desulfovibrio gigas ferredoxin II (DgFdII) is a small protein with a polypeptide chain composed of 58 amino acids, containing one Fe3S4 cluster per monomer. Upon studying the redox cycle of this protein, we detected a stable intermediate (FdIIint) with four 1H resonances at 24.1, 20.5, 20.8 and 13.7 ppm. The differences between FdIIox and FdIIint were attributed to conformational changes resulting from the breaking/formation of an internal disulfide bridge. The same 1H NMR methodology used to fully assign the three cysteinyl ligands of the [3Fe-4S] core in the oxidized state (DgFdIIox) was used here for the assignment of the same three ligands in the intermediate state (DgFdIIint). The spin-coupling model used for the oxidized form of DgFdII where magnetic exchange coupling constants of around 300 cm-1 and hyperfine coupling constants equal to 1 MHz for all the three iron centres were found, does not explain the isotropic shift temperature dependence for the three cysteinyl cluster ligands in DgFdIIint. This study, together with the spin delocalization mechanism proposed here for DgFdIIint, allows the detection of structural modifications at the [3Fe-4S] cluster in DgFdIIox and DgFdIIint.

Deuterium NMR is used to examine the molecular order exhibited by an organosiloxane tetrapode giving the first experimental evidence, using a bulk sample, for the existence of a biaxial nematic phase in this type of compounds. The temperature dependence of the averaged quadrupolar coupling constant and asymmetry parameter was determined in the compound's nematic phase. Two distinct regimes could be identified, one with a vanishing asymmetry parameter corresponding to a uniaxial nematic phase and another with a significant temperature dependent asymmetry parameter, corresponding to a biaxial nematic phase. The high values obtained for the asymmetry parameter at the lower end of the nematic range are well above experimental error and constitute a definite proof of the biaxial nature of the nematic phase exhibited by the studied compound for those temperatures.

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Recently reported decameric vanadate (V(10)) high affinity binding site in myosin S1, suggests that it can be used as a tool in the muscle contraction regulation. In the present article, it is shown that V(10) species induces myosin S1 cleavage, upon irradiation, at the 23 and 74 kDa sites, the latter being prevented by actin and the former blocked by the presence of ATP. Identical cleavage patterns were found for meta- and decavanadate solutions, indicating that V(10) and tetrameric vanadate (V(4)) have the same binding sites in myosin S1. Concentrations as low as 50 muM decavanadate (5 muM V(10) species) induces 30% of protein cleavage, whereas 500 muM metavanadate is needed to attain the same extent of cleavage. After irradiation, V(10) species is rapidly decomposed, upon protein addition, forming vanadyl (V(4+)) species during the process. It was also observed by NMR line broadening experiments that, V(10) competes with V(4) for the myosin S1 binding sites, having a higher affinity. In addition, V(4) interaction with myosin S1 is highly affected by the products release during ATP hydrolysis in the presence or absence of actin, whereas V(10) appears to be affected at a much lower extent. From these results it is proposed that the binding of vanadate oligomers to myosin S1 at the phosphate loop (23 kDa site) is probably the cause of the actin stimulated myosin ATPase inhibition by the prevention of ATP/ADP exchange, and that this interaction is favoured for higher vanadate anions, such as V(10).

As was recently published in the GERPISA newsletter, one of the aims of the research for the new years will be the knowledge of interactions between the organisational company dynamics and the social-economical models of development. If one takes the example of the German exercise in the framework of FUTUR programme, one of the main thematic groups that emerged from the first discussions was preciselly “Mobility: individually atractive and socially sustainable”. Also the IMVP programme at MIT is taking these questions on the “visions for a sustainable future” theme. In the same way the WorTiS Project analysed several scenario topics on the issue of mobility and automotive industry. Those scenario topics are explained and justified in this research paper.

This work reports on the direct electrochemistry of the Desulfovibrio gigas aldehyde oxidoreductase (DgAOR), a molybdenum enzyme of the xanthine oxidase family that contains three redox-active cofactors: two [2Fe-2S] centers and a molybdopterin cytosine dinucleotide cofactor. The voltammetric behavior of the enzyme was analyzed at gold and carbon (pyrolytic graphite and glassy carbon) electrodes. Two different strategies were used: one with the molecules confined to the electrode surface and a second with DgAOR in solution. In all of the cases studied, electron transfer took place, although different redox reactions were responsible for the voltammetric signal. From a thorough analysis of the voltammetric responses and the structural properties of the molecular surface of DgAOR, the redox reaction at the carbon electrodes could be assigned to the reduction of the more exposed iron cluster, [2Fe-2S] II, whereas reduction of the molybdopterin cofactor occurs at the gold electrode. Voltammetric results in the presence of aldehydes are also reported and discussed.

The unambiguous assignment of the nuclear magnetic resonance (NMR) signals of the α-substituents of the haems in the tetrahaem cytochrome isolated from Shewanella frigidimarina NCIMB400, was made using a combination of homonuclear and heteronuclear experiments. The paramagnetic 13C shifts of the nuclei directly bound to the porphyrin of each haem group were analysed in the framework of a model for the haem electronic structure. The analysis yields g-tensors for each haem, which allowed the assignment of some electron paramagnetic resonance (EPR) signals to specific haems, and the orientation of the magnetic axes relative to each haem to be established. The orientation of the axial ligands of the haems was determined semi-empirically from the NMR data, and the structural results were compared with those of the homologous tetrahaem cytochrome from Shewanella oneidensis MR-1 showing significant similarities between the two proteins.

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