Purification and Characterization of the alpha-Glucosidase Produced by Thermophilic Fungus Thermoascus aurantiacus CBMAI 756

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Increased Androgen Receptor and Remodeling in the Prostatic Stroma After the Inhibition of 5-Alpha Reductase and Aromatase in Gerbil Ventral Prostate

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Long-term inhibition of 5-alpha reductase and aromatase changes the cellular and extracellular compartments in gerbil ventral prostate at different postnatal ages

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Oxidative Stability and alpha-Tocopherol Retention in Soybean Oil with Lemon Seed Extract (Citrus Limon) under Thermoxidation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tertiary structural changes of the alpha-hemolysin from Staphylococcus aureus on association with liposome membranes

The interaction of alpha-hemolysin (also called alpha-toxin) from Staphylococcus aureus with mixed egg-yolk phosphatidylcholine/cholesterol liposomes has been investigated using the intrinsic tryptophan fluorescence emission (ITFE) signal. The ITFE intensity of alpha-hemolysin, which was obtained using a novel purification protocol, showed a triphasic increase on incubation with liposomes at low protein/lipid ratios. The first, rapid phase results in an increase in ITFE of 10%, which reflects rapid conformation changes in the alpha-hemolysin on association with the liposome membrane, the second phase of the ITFE increase is associated with a red shift from 334 to 339 nm in the maximum emission wavelength, suggesting the transition to a partially unfolded intermediate in the oligomerization process. The third phase of the ITFE intensity change demonstrates a temporal correlation with the appearance of SDS-stable oligomers. The results demonstrate the feasibility of identification of intermediate protein conformations in complex membrane-associated processes by manipulation of the liposomal membrane composition. (C) 1998 Academic Press.

A stability transition at mildly acidic pH in the alpha-hemolysin (alpha-toxin) from Staphylococcus aureus

The effects of mildly acidic conditions on the free energy of unfolding (Delta G(u)(buff)) of the pore-forming alpha-hemolysin (alpha HL) from Staphylococcus aureus were assessed between pH 5.0 and 7.5 by measuring intrinsic tryptophan fluorescence, circular dichroism and elution time in size exclusion chromatography during urea denaturation, Decreasing the pH from 7.0 to 5.0 reduced the calculated Delta G(u)(buff) from 8.9 to 4.2 kcal moI(-1), which correlates with an increased rate of pore formation previously observed over the same pH range, It is proposed that the lowered surface pH of biological membranes reduces the stability of alpha HL thereby modulating the rate of pore formation. (C) 1999 Federation of European Biochemical Societies.

Crystal structure of the platelet activator convulxin, a disulfide-linked alpha(4)beta(4) cyclic tetramer from the venom of Crotalus durissus terrificus

Convulxin (CVX), a C-type lectin, isolated from the venom of the South American rattlesnake Crotalus durissus terrificus, causes cardiovascular and respiratory disturbances and is a potent platelet activator which hinds to platelet glycoprotein GPVI. The structure of CVX has been solved at 2.4 Angstrom resolution to a crystallographic residual of 18.6% (R-free =26.4%). CVX is a disulfide linked heterodimer consisting of homologous alpha and beta chains. The heterodimers are additionally linked by disulfide bridges to form cyclic alpha(4)beta(4)heterotetramers. These domains exhibit significant homology to the carbohydrate-binding domains of C-type lectins, to the factor IX-binding protein (IX-bp), and to flavocetin-A (Fl-A) but sequence and Structural differences are observed in both the domains in the putative Ca2+ and carbohydrate binding regions. (C) 2003 Elsevier B.V. All rights reserved.

Crystallization and preliminary X-ray crystallographic studies of Protac (R), a commercial protein C activator isolated from Agkistrodon contortrix contortrix venom

The protein C pathway plays an important role in the control and regulation of the blood coagulation cascade and prevents the propagation of the clotting process on the endothelium surface. In physiological systems, protein C activation is catalyzed by thrombin, which requires thrombomodulin as a cofactor. The protein C activator from Agkistrodon contortrix contortrix acts directly on the zymogen of protein C converting it into the active form, independently of thrombomodulin. Suitable crystals of the protein C activator from Agkistrodon contortrix contortrix were obtained from a solution containing 2 M ammonium sulfate as the precipitant and these crystals diffracted to 1.95 angstrom resolution at a synchrotron beamline. The crystalline array belongs to the monoclinic space group C2 with unit cell dimensions a=80.4, b = 63.3 and c = 48.2 angstrom, alpha = gamma = 90.0 degrees and beta = 90.8 degrees. (C) 2005 Elsevier B.V. All rights reserved.

Structural studies of BmooMP alpha-I, a non-hemorrhagic metalloproteinase from Bothrops moojeni venom

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of TNF-alpha blockers on the oral prevalence of opportunistic microorganisms in ankylosing spondylitis patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The natural radioactivity in water by gross alpha and beta measurements

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diffusion and interface controlled reactions in alpha-(Cu-Al-Ag) alloys

The isothermal kinetics of Ag precipitation was studied in Cu-Al-Ag alloys with concentrations ranging from 2 to 8 wt.%Al and 2 to 12 wt.%Ag, using scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDX) and microhardness measurements. The results indicated a change in the precipitates growing mechanism from diffusion to interface controlled process, probably due to a change in the nature of the interface with the Ag and Al enrichment of the precipitates. (C) 2006 Elsevier B.V. All rights reserved.

Precipitation reaction in alpha-Cu-Al-Ag alloys

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biomimetic synthesis of xuxuarines E alpha and E beta: Structure revision of Rzedowskia bistriterpenoids

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.