Kinetic role of a histidine residue in the T1 copper site of the laccase from Rigidoporus lignosus

Laccases (benzendiol:oxygen oxidoreductases; EC 1.10.3.2) catalyze the oxidation of a broad range of substrates, such as polyphenols, dyes and pollutants, and thus these enzymes are widely applied in industrial, biotechnological and environmental fields. In order to improve their biotechnological applications, a deep knowledge of structural factors involved in controlling their activity, in various experimental conditions and on different substrates, is required. In the present study, a laccase from the mushroom Rigidoporus lignosus was kinetically characterized. In particular, the stability, the effects of pH, ionic strength and fluoride ion concentration on the kinetic parameters were investigated, using three di-hydroxy-benzene isomers (1,2-dihydroxy-benzene, 1,3-dihydroxy-benzene and 1,4-dihydroxy-benzene) as substrates. The catalytic constant values of the laccase showed a bell-shaped pH profile, with the same optimum pH and pK(a) values for all tested substrates. This behavior appears to be due to the presence of an ionizable residue in the enzyme active site. To identify this residue, the enzyme was derivatized with diethylpyrocarbonate to modify accessible histidine residues, which, according to structural data, are present in the active site of this enzyme. The kinetic behavior of the derivatized laccase was compared with that of the native enzyme and the derivatized residues were identified by mass spectrometry. Mass spectrometry and kinetic results suggest the main role of His-457 in the control of the catalytic activity of laccase from R. lignosus. (C) 2013 Elsevier B.V. All rights reserved.

Stimuli-Responsive Biointerface Based on Polymer Brushes for Glucose Detection

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

Characterization of metal-biomass interactions in the lanthanum(III) biosorption on Sargassum sp using SEM/EDX, FTIR, and XPS: Preliminary studies

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Highly Ordered TiO2 Nanotubes for Electrochemical Sensing of Hair Dye Basic Brown 17

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

RAMSY: Ratio Analysis of Mass Spectrometry to Improve Compound Identification

The complexity of biological samples poses a major challenge for reliable compound identification in mass spectrometry (MS). The presence of interfering compounds that cause additional peaks in the spectrum can make interpretation and assignment difficult. To overcome this issue, new approaches are needed to reduce complexity and simplify spectral interpretation. Recently, focused on unknown metabolite identification, we presented a new approach, RANSY (ratio analysis of nuclear magnetic resonance spectroscopy; Anal. Chem. 2011, 83, 7616-7623), which extracts the signals related to the same metabolite based on peak intensity ratios. On the basis of this concept, we present the ratio analysis of mass spectrometry (RAMSY) method, which facilitates improved compound identification in complex MS spectra. RAMSY works on the principle that, under a given set of experimental conditions, the abundance/intensity ratios between the mass fragments from the same metabolite are relatively constant. Therefore, the quotients of average peak ratios and their standard deviations, generated using a small set of MS spectra from the same ion chromatogram, efficiently allow the statistical recovery of the metabolite peaks and facilitate reliable identification. RAMSY was applied to both gas chromatography/MS and liquid chromatography tandem MS (LC-MS/MS) data to demonstrate its utility. The performance of RAMSY is typically better than the results from correlation methods. RAMSY promises to improve unknown metabolite identification for MS users in metabolomics or other fields.

Influência ao consumo crônico de álcool no fêmur de ratos machos e fêmeas

Considering that alcohol has been identified, in the literature, as an evident risk factor for osteoporosis development, inducing loss of bone mass, the aim of this study was to evaluate the effect of the alcohol on the femur of male and female rats. For this purpose, 35 male and 35 female rats, divided into seven groups of five animals per genera were included. The groups were: control group that received food and water as much as they wished; alcohol group in the concentrations of 10, 20 and 30% and the isocalorie: groups corresponding to the concentration of alcohol. After 8 weeks, the animals were sacrificed and evaluated regarding to the body weight and nutritional conditions. Unilateral femurs were removed and analyzed in relation to the length, width, and thickness of the bone cortical, trabeculae percentage and optical density. Data obtained were analyzed by ANOVA (Tukey; p<0.05). Regarding to the weight, loss of weight was observed in the animals of the group alcohol 20% among females and 30% among the males. In relation to the nutritional conditions, the females with the dosages of 10, 20 and 30% of alcohol swallowed a mean of 25, 39 and 53% of Kcall and the males 22, 36 and 45 Kcal Jday coming from the alcohol. Alcohol reduced the length of the femur only in the group MG6. Mesio-distal width was higher in the group FG6 although the antero-posterior width was not modified. The cortical thickness among males and females was not altered however the percentage of trabeculae bone was reduced among females alcohol 30% and among males with the three alcoholic concentrations. Optical density was reduced in the concentration of 30% among the males and females. Under the experimental conditions, it could be concluded that the effect of alcohol was more evident among the males and in the trabeculae bone, and that the alcoholic concentration of 30% was the most harmful for the bone tissue, ....

Bonding durability of dental sealants to deciduous and permanent teeth

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

Avaliação goniométrica da amplitude de movimento do ombro de crianças praticantes de beisebol

Introduction: Baseball is a Sport disputed by two teams composed at least by nine players which compete between themselves in a game of six innings in the amateur game, for children up to 10 years old. Objective: The objective is to compare the movement degrees of the shoulder joint between the dominant and the non dominant shoulder. Methods: Eleven male subjects were assessed (8,63 ± 0,67 years old) whom practiced baseball at the Nikkey Club of the city of Marília – SP. All of the subjects were assessed by the same examiner, whom measured the range of motion (ROM) of both glenohumeral joint. The Student t test was used for the comparison of the shoulders, with level of significance of 5% (p≤0,05). Results: The subjects presented significant differences on the external rotation movement (p= 0,014) between the dominant shoulder (63,63 ± 12,92°) and the non dominant shoulder (55,45 ± 16,27°), and in the internal rotation movement (p= 0,001) between the dominant shoulder (32,90 ± 5,68°) and the non dominant shoulder (40,72 ± 5,74°). Conclusion: The results obtained in this study, on the experimental conditions utilized, allow us to conclude that the practice of baseball influence the range of motion of external rotation and internal rotation of the dominant shoulder, with increased external rotation, and a decreased internal rotation, provoking instability of the shoulder joint.

Efeito de diferentes fontes luminosas e pré-condicionamento do esmalte na alteração de cor, penetração de H2O2 e citotoxicidade em dentes clareados

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

Metilação de mercúrio em águas da região amazônica na presença e ausência de macrófitas: experimentos em microcosmos

Pós-graduação em Química - IQ

Avaliação in vitro da resistência adesiva de braquetes ortodônticos variando-se o tempo de armazenamento e o tipo de fotoativação: luz halógena e led

O objetivo deste estudo in vitro foi comparar os efeitos da fotoativação pelos sistemas luz halógena e LED na adesão de braquetes ortodônticos em diferentes tempos pós-colagem (imediato, 24h e 7d). Braquetes com adesivo pré-aplicado (Gemini series; APC adhesive precoated brackets; 3M Unitek, USA) foram colados na superfície vestibular de dentes bovinos. O esmalte dos dentes foi condicionado utilizando-se o primer auto-condicionante (Transbond SEP, 3M Unitek, USA) em todos os espécimes, conforme recomendações do fabricante. Setenta e dois dentes foram divididos em 2 grupos (n=36), conforme o sistema de fotoativação (luz halógena ou LED) e sub-divididos (n=12) de acordo com o tempo pós-colagem. Para os grupos luz halógena, o tempo de fotoativação foi de 20s e para os grupos LED foi de 10s. O teste de resistência ao cisalhamento foi realizado com auxílio de uma máquina de ensaios universal nos diferentes tempos pós-colagem: imediato, 24h e 7d. O valor médio de adesão para os grupos luz halógena foi de 20,01±5,24MPa e, para os grupos fotoativados pelo sistema LED 17,35±5,07MPa, sendo estes resultados estatisticamente diferentes. Quando comparado o efeito do tempo pós-colagem, os resultados revelaram que os valores de adesão foram significantemente maiores para o tempo de 7d. O resultado do teste ANOVA 2 – fatores revelou não existir diferença estatística entre a interação sistema de fotoativação e tempos pós-colagem. O teste de Tukey mostrou que para as 4 condições experimentais nos tempos imediato e 24h, os resultados não diferiram estatisticamente, independentemente do sistema de fotoativação. Somente com relação ao grupo luz halógena-7d, os resultados mostraram diferenças estatisticamente significantes. O grupo LED-7d desempenhou comportamento intermediário entre os grupos. O índice de adesivo remanescente não revelou diferenças... (Resumo completo, clicar acesso eletrônico abaixo)

Evaluation of the Parameters Affecting the Photoelectrocatalytic Reduction of CO2 to CH3OH at Cu/Cu2O Electrode

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

Limits of Visual Detection for Finasteride Polymorphs in Prepared Binary Mixtures: Analysis by X-ray Powder Diffraction

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

Toxicity on aquatic organisms exposed to secondary effluent disinfected with chlorine, peracetic acid, ozone and UV radiation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effectiveness of therapeutic agents in disease treatment in Piaractus mesopotamicus

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