976 resultados para Beta(4)-adrenoceptor
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Botryosphaeran, a new exopolysaccharide from the endophytic fungus Botryosphaeria rhodina MAMB-05, and algal laminarin were hydrolyzed by partially-fractionated enzymes of the beta-glucanolytic complex from Trichoderma harzianum Rifai. beta-Glucanase fractions (F-I and F-II) separated by gel permeation chromatography presented different modes of attack on botryosphaeran and laminarin. Botryosphaeran was hydrolyzed to the extent of 66% (F-I) and 98% (F-II) within 30 min, and its main hydrolysis products were gluco-oligosaccharides of DP >= 4, with lesser amounts of glucose, di- and tri-saccharides. The action of enzyme fractions I and II on laminarin resulted in 15% conversion to glucose, while the percentage of saccharification was radically different (70% for F-I and 25% for F-II). The different product arrays within the polysaccharide hydrolysates can be explained by the difference in the enzymes' specificities within each enzyme fraction, and the molecular structures of the polysaccharides and their complexity.
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The thermophilic fungus Thermoascus aurantiacus 179-5 and the mesophilic Aureobasidium pullulans ER-16 were cultivated in corn-cob by solid state fermentation for P-glucosidase production. After fermentation both enzymes were purified. The beta-glucosidases produced by the strains A. pullulans and T aurantiacus were most active at pH 4.0-4.5 and 4.5, with apparent optimum temperatures at 80 and 75 degrees C, respectively. Surprisingly, the enzyme produced by the mesophilic A. pullulans was stable over a wider range of pH (4.5-9.5 against 4.5-6.5) and more thermostable (98% after 1 h at 75 degrees C against 98% after 1 h at 70 degrees C) than the enzyme from the thermophilic T. aurantiacus. The t((1/2)) at 80 degrees C were 90 and 30 min for A. pullulans and T. aurantiacus, respectively. beta-Glucosidase thermoinactivation followed first-order kinetics and the energies of denaturation were 414 and 537 kJ mol(-1) for T. aurantiacus and A. pullulans, respectively. The result showed that beta-glucosidase obtained from the mesophilic A. pullulans is more stable than that obtained from the thermophilic T. aurantiacus. (C) 2007 Elsevier Ltd. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The effect of 4 mass% Ag addition on the thermal behavior of the Cu-9 mass% Al alloy was studied using differential scanning calorimetry (DSC), optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffractometry (XRD). The results showed that the presence of silver causes (Cu)-alpha+(alpha+gamma1)-->(Cu)-alpha+beta transformation to occur in two stages. In the first one, part of the produced beta phase combines with the precipitated Ag to give a silver-rich phase and in the second one the transformation is completed. The formation of this silver-rich phase seems to be enhanced at very low cooling rates.
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The influence of 4 wt.%Ag addition on the isothermal decomposition kinetics of the beta' phase in the Cu-9wt.%Al alloy was studied by microhardness measurements, optical and scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and X-ray diffractometry. The results showed that the presence of Ag decreases the beta' --> (alpha + gamma(1)) decomposition reaction rate in the Cu-9%Al-4%Ag alloy, an effect that may be associated to the gamma(1) phase which catalyses the Ag precipitation, making it faster than the decomposition reaction, and thus, stabilizing the martensitic phase. (C) 2003 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Reaction of pristimerin with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in a biomimetic-type coupling leading to xuxuarines E alpha and E beta and not the previously reported Rzedowskia bistriterpenoids I and II suggesting that the structures proposed for these natural products need revision. A product obtained in this reaction by an unusual Diels-Alder addition followed by retro-Diels-Alder-type elimination was characterized as pristimerin dicyanophenalenedione. Complete H-1, and C-13 NMR spectral assignments of xuxuarines Ea and Eb have been made by the application of 1D and 2D NMR techniques. (c) 2007 Elsevier Ltd. All rights reserved.
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The synthesis and characterization of a new organic ligand monooctyldiphenylphosphinate (L) is described, as well as a new Eu(3+) diketonate complex [Eu(tta)(3)(L)(2)] (tta = thenoyltrifluoracetone). The ligand (L) was formed by substitution reaction (80% yield) and characterized by uni- and bidimensional (1)H, (13)C and (31)P NMR experiments, to confirm its molecular structure. The coordination of (L) to Eu(3+) in the complex [Eu(tta)(3)(L)(2)] was confirmed by FT-IR spectra. The emission spectra present the same profile when excited in Eu(3+) or in the ligands, suggesting an energy transfer from ligands to Eu(3+) ions. The emission spectra of the precursor [Eu(tta)(3)(H(2)O)(2)], and [Eu(tta)(3)(L(2))] present bands arising from f-f intra-configurational transitions. The only (5)D(0)-(7)F(0) transition shows the presence of at least one site without symmetry center. The FWHM of such transition is 7 cm(-1) and 57 cm(-1) for [Eu(tta)(3)(H(2)O)(2)] and [Eu(tta)(3)(L)(2)] complexes, respectively. This widening is provided by the presence of large groups around Eu(3+) ion. The calculated intensity parameters Omega(2) and Omega(4) show that the interaction features between center-ion and ligand are different; the small value of Omega(4) is related to long range effects of alkyl chain. The Langmuir isotherms of this ligand and complex have been investigated although their hydrolysis in water subphase does not allow stable monolayers. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)