Platelet-rich plasma stimulates cytokine expression and alkaline phosphatase activity in osteoblast-derived osteosarcoma cells

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

Partial purification and properties of cellulase-free alkaline xylanase produced by Rhizopus stolonifer in solid-state fermentation

Rhizopus stolonifer was cultivated in wheat bran to produce a cellulase-free alkaline xylanase. The purified enzyme obtained after molecular exclusion chromatography in Sephacryl S-200 HR showed optimum temperature as 45 degrees C and hydrolysis pHs optima as pH 6.0 and 9.0. Xylanase presented higher Vmax at pH 9.0 (0.87 mu mol/mg protein) than at pH 6.0 and minor Km at pH 6.0 (7.42 mg/mL)than at pH 9.0.

Purification and properties of an alkaline protease of Aspergillus clavatus

An extracellular alkaline serine protease has been purified from a strain of Aspergillus clavatus, to apparent homogeneity, by ammonium sulfate precipitation and chromatography on Sephadex G-75. Its molar mass, estimated by SDS-PAGE, was 35 kDa. Maximum protease activity was observed at pH 9.5 and 40 degrees C. The enzyme was active between pH 6.0 and 11.0 and was found to be unstable up to 50 degrees C. Calcium at 5 mM increased its thermal stability. The protease was strongly inhibited by PMSF and chymostatin as well as by SDS, Tween 80 and carbonate ion. Substrate specificity was observed with N-p-Tos-Gly-Pro-Arg-p-nitroanilide and N-Suc-Ala-Ala-Ala-p-nitroanilide being active substates. Parts of the amino acid sequence were up to 81% homologous with those of several fungal alkaline serine proteases.

Production, partial characterization, and immobilization in alginate beads of an alkaline protease from a new thermophilic fungus Myceliophthora sp.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ventilatory compensation of the alkaline tide during digestion in the snake Boa constrictor

The increased metabolic rate during digestion is associated with changes in arterial acid-base parameters that are caused by gastric acid secretion (the 'alkaline tide'). Net transfer of HCl to the stomach lumen causes an increase in plasma HCO3- levels, but arterial pH does not change because of a ventilatory compensation that counters the metabolic alkalosis. It seems, therefore, that ventilation is controlled to preserve pH and not P-CO2, during the postprandial period. To investigate this possibility, we determined arterial acid-base parameters and the metabolic response to digestion in the snake Boa constrictor, where gastric acid secretion was inhibited pharmacologically by oral administration of omeprazole. The increase in oxygen consumption of omeprazole-treated snakes after ingestion of 30% of their own body mass was quantitatively similar to the response in untreated snakes, although the peak of the metabolic response occurred later (36 h versus 24 h). Untreated control animals exhibited a large increase in arterial plasma HCO3- concentration of approximately 12 mmol 1(-1), but arterial pH only increased by 0.12 pH units because of a simultaneous increase in arterial P-CO2 by about 10 mmHg. Omeprazole virtually abolished the changes in arterial pH and plasma HCO3- concentration during digestion and there was no increase in arterial P-CO2. The increased arterial P-CO2 during digestion is not caused, therefore, by the increased metabolism during digestion or a lower ventilatory responsiveness to ventilatory stimuli during a presumably relaxed state in digestion. Furthermore, the constant arterial P-CO2, in the absence of an alkaline tide, of omeprazole-treated snakes strongly suggests that pH rather than P-CO2 normally affects chemoreceptor activity and ventilatory drive.

Purification and characterization of a new alkaline serine protease from the thermophilic fungus Myceliophthora sp.

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

The late precambrian K-alkaline magmatism in the Ribeira Fold Belt: a case study of the Piracaia Pluton, State of São Paulo, SE Brazil, and its potential mineralization (Cu, Zn, Gd)

The Pluriserial Ribeira Magmatic System-590 of the Late Precambrian Ribeira Fold Belt comprises seven groups of high-K rocks of crustal or mantle origin with ages ranging between 620 and 570 Ma. One of these groups is represented by transalkaline suites akin to appinitic lamprophyres. The suites assemble one or more of following lithologies: (+/- quartz) gabbros and monzogabbros, (+/- quartz) diorites and monzodiorites, (+/- quartz) monzonites and syenites in addition to rare granites. All these rocks occur together in the Piracaia pluton, State of São Paulo. The mineralogy of the Piracaia suite comprises variable amounts of plagioclase (An 60-10), alkali-feldspars (orthoclase, microcline, albite), ortho- (Fe-hypersthene) and clinopyroxenes (augite), amphiboles (hornblende and rare late Fe-hastingsite), abundant biotite, quartz, opaques, sphene, allanite and zircon. Several magmatic pulses constructed the pluton. The Piracaia magma bulk trend evolved initially along the silica-undersaturation plane with simultaneous fractionation of accessory, mafic and felsic minerals. These are segregated in feldspar-rich cumulates. In the late stage, the evolutionary trend followed two distinct paths: one along the or-ab thermal barrier with the crystallization of syenites; the second one along the thermal valley in the or-ab-qz subsystem, producing quartz-syenites and granites. The source of the Piracaia magma was a 'vein-plus-wall-rock-system '. Together the pulses reflect increasing and decreasing participation of peridotites and mica pyroxenites, respectively, in the magmatogenic process. The magmatic pulses were stored in magma chambers, several drained by deep faults or fractures, which were successively reactivated and recharged. Each new pulse underwent mixing with earlier residual magma, followed by fractionation. During ascent through the hot and thickened post-collisional crust, the magma pulses underwent minor compositional changes by crustal contamination. The concentration of valuable elements (Cu, Zn, Gd) in the Piracaia pluton occurred during two phases of the magmatic evolution. Cu and Zn were enriched in cumulates and Gd was concentrated in residual quartz-syenitic veins. Due to their homogeneous dark colour and texture, the monzodiorites are exploited both for polished dimension stones and supports for sensitive scientific instruments. (C) 2001 Elsevier B.V. Ltd. All rights reserved.

Utilization of electrochemical impedance spectroscopy for monitoring bornite (CU5FeS4) oxidation by Acidithiobacillus ferrooxidans

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

Indole ring oxidation by activated leukocytes prevents the production of hypochlorous acid

Hypochlorous acid (HOCl) released by activated leukocytes has been implicated in the tissue damage that characterizes chronic inflammatory diseases. In this investigation, 14 indole derivatives, including metabolites such as melatonin, tryptophan and indole-3-acetic acid, were screened for their ability to inhibit the generation of this endogenous oxidant by stimulated leukocytes. The release of HOCl was measured by the production of taurine-chloramine when the leukocytes (2 x 10(6) cells/mL) were incubated at 37ºC in 10 mM phosphate-buffered saline, pH 7.4, for 30 min with 5 mM taurine and stimulated with 100 nM phorbol-12-myristate acetate. Irrespective of the group substituted in the indole ring, all the compounds tested including indole, 2-methylindole, 3-methylindole, 2,3-dimethylindole, 2,5-dimethylindole, 2-phenylindole, 5-methoxyindole, 6-methoxyindole, 5-methoxy-2-methylindole, melatonin, tryptophan, indole-3-acetic acid, 5-methoxy-2-methyl-3-indole-acetic acid, and indomethacin (10 µM) inhibited the chlorinating activity of myeloperoxidase (MPO) in the 23-72% range. The compounds 3-methylindole and indole-3-acetic acid were chosen as representative of indole derivatives in a dose-response study using purified MPO. The IC50 obtained were 0.10 ± 0.03 and 5.0 ± 1.0 µM (N = 13), respectively. These compounds did not affect the peroxidation activity of MPO or the production of superoxide anion by stimulated leukocytes. By following the spectral change of MPO during the enzyme turnover, the inhibition of HOCl production can be explained on the basis of the accumulation of the redox form compound-II (MPO-II), which is an inactive chlorinating species. These results show that indole derivatives are effective and selective inhibitors of MPO-chlorinating activity.

Effect of hydrogen charging on the stability of SAE 10B22 steel surface in alkaline solutions

The influence of hydrogen charging into a quenched and tempered boron steel membrane electrode (SAE 10B22) was studied using borate buffer (pH 8.4) and NaOH solutions (pH 12.7), with or without the addition of 0.01 M EDTA. At the hydrogen input side, hydrogen charging influenced cyclic voltammograms increasing the anodic charge of iron(II) hydroxide formation, and decreasing the donor density of passive films. These results suggest that the hydrogen ingress caused instability of metallic surface, increasing the surface area activity. (C) 2005 Elsevier Ltd. All rights reserved.

Electrochemical Oxidation of Hydroxylamine on Gold in Aqueous Acidic Electrolytes: An in Situ SERS Investigation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)