Overexpression of UCP1 in tobacco induces mitochondrial biogenesis and amplifies a broad stress response

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

A candidate short-term toxicity test using Ampelisca brevicornis to assess sublethal responses to pharmaceuticals bound to marine sediments

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Selenium and sulfur: mitigation in plant stresses

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Agua de reuso e seu efeito sobre parâmetros fisiológicos em manjericão (Ocimum basilicum L.)

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

The zymogen-enteropeptidase system: A practical approach to study the regulation of enzyme activity by proteolytic cleavage

The present research describes an efficient procedure to obtain high levels of trypsinogen and chymotrypsinogen by using a simple, rapid, and easily reproducible method. The extraction process and the time-course of activation of zymogens can be carried out in a single laboratory period, without sophisticated equipment. The main objective was to prepare a laboratory class that would stimulate student interest in enzyme regulation, exploring the fact that the catalytic activity of some enzymes is regulated by different mechanisms. The regulation of proteolytic enzymes requires the synthesis of an inactive zymogen and its being irreversibly switched on by specific proteolytic cleavage.

The influence of ripening stage and cultivation system on the total antioxidant activity and total phenolic compounds of yellow passion fruit pulp

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

Influence of the cultivation system in the aroma of the volatile compounds and total antioxidant activity of passion fruit

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determination of Oxalate in Grass by FIA with a Spectrophotometric Detection System Using a Two Enzyme Reactor

A new methodology for soluble oxalic acid determination in grass samples was developed using a two enzyme reactor in an FIA system. The reactor consisted of 3 U of oxalate oxidase and 100 U of peroxidase immobilized on Sorghum vulgare seeds activated with glutaraldehyde. The carbon dioxide was monitored spectrophotometrically, after reacting with an acid-base indicator (Bromocresol Purple) after it permeated through a PTFE membrane. A linear response range was observed between 0.25 and 1.00mmol l-1 of oxalic acid; the data was fit by the equation A=-0.8(±1.5)+ 57.2(±2.5)[oxalate], with a correlation coefficient of 0.9971 and a relative standard deviation of 2% for n=5. The variance for a 0.25 mmol l-1 oxalic acid standard solution was lower than 4% for 11 measurements. The FIA system allows analysis of 20 samples per hour without prior treatment. The proposed method showed a good correlation with that of the Sigma Kit.

Oxalate determination in urine using an immobilized enzyme on Sorghum vulgare seeds in a flow injection conductimetric system

A flow-injection (FI) method was developed for the determination of oxalate in urine. It was based on the use of oxalate oxidase (E.C. 1.2.3.4) immobilized on ground seeds of the BR-303 Sorghum vulgare variety. A reactor was filled with this activated material, and the samples (200 μL) containing oxalate were passed through it, carried by a deionized water flow. The carbon dioxide produced by the enzyme reaction permeated through a microporous PTFE membrane, and was received in a water acceptor stream, promoting conductivity changes proportional to the oxalate concentration in the sample. The results obtained showed a useful linear range from 0.05 to 0.50 mmol dm-3. The proposed method, when compared with the Sigma enzymatic procedure, showed good correlation (Y = 0.006(±0.016) + 0.98(±0.019)X; r = 0.9995, Y = conductivity in μS, and X = concentration in mmol dm-3), selectivity, and sensitivity. The new immobilization approach promotes greater stability, allowing oxalate determination for 6 months. About 13 determinations can be performed per hour. The precision of the proposed method is about ± 3.2 % (r.s.d).

Effect of potassium sources on the antioxidant activity of eggplant

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Host-guest system of 4-nerolidylcatechol in 2-hydroxypropyl-beta-cyclodextrin: preparation, characterization and molecular modeling

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Construction of an alkaline phosphatase-liposome system: a tool for biomineralization study

Alkaline phosphatase is required for the mineralization of bone and cartilage. This enzyme is localized in the matrix vesicle, which plays a role key in calcifying cartilage. In this paper. we standardize a method for construction an alkaline phosphatase liposome system to mimic matrix vesicles and examine a some kinetic behavior of the incorporated enzyme. Polidocanol-solubilized alkaline phosphatase, free of detergent, was incorporated into liposomes constituted from dimyristoylphosphatidylcholine (DMPC), dilaurilphosphatidylcholine (DLPC) or dipalmitoylphosphatidylcholine (DPPC). This process was time-dependent and >95% of the enzyme was incorporated into the liposome after 4 h of incubation at 25 degreesC. Although, incorporation was more rapid when vesicles constituted from DPPC were used, the incorporation was more efficient using vesicles constituted from DMPC. The 395 nm diameter of the alkaline phosphatase-liposome system was relatively homogeneous and more stable when stored at 4 degreesC.Alkaline phosphatase was completely released from liposome system only using purified phosphatidylinositol-specific phospholipase C (PIPLC). These experiments confirm that the interaction between alkaline phosphatase and lipid bilayer of liposome is via GPI anchor of the enzyme, alone. An important point shown is that an enzyme bound to liposome does not lose the ability to hydrolyze ATP, pyrophosphate and p-nitrophenyl phosphate (PNPP), but a liposome environment affects its kinetic properties, specifically for pyrophosphate.The standardization of such system allows the study of the effect of phospholipids and the enzyme in in vitro and in vivo mineralization, since it reproduces many essential features of the matrix vesicle. (C) 2002 Elsevier B.V. Ltd. All rights reserved.

Erythrocyte ghost cell-alkaline phosphatase: construction and characterization of a vesicular system for use in biomineralization studies

Alkaline phosphatase is required for the mineralization of bone and cartilage. This enzyme is localized in the matrix vesicle, which plays a role key in calcifying cartilage. In this paper we standardize a method to construction a resealed ghost cell-alkaline phosphatase system to mimic matrix vesicles and examine the kinetic behavior of the incorporated enzyme. Polidocanol-solubilized alkaline phosphatase, free of detergent, was incorporated into resealed ghost cells. This process was time-dependent and practically 50% of the enzyme was incorporated into the vesicles in 40 h of incubation, at 25 degreesC. Alkaline phosphatase-ghost cell systems were relatively homogeneous with diameters of about 300 nm and were more stable when stored at -20 degreesC.Alkaline phosphatase was completely released from the resealed ghost cell-system using only phospholipase C. These experiments confirm that the interaction between alkaline phosphatase and the lipid bilayer of resealed ghost cell is exclusively via glycosylphosphatidylinositol (GPI) anchor of the enzyme.An important point shown is that an enzyme bound to resealed ghost cell does not lose the ability to hydrolyze ATP, pyrophosphate and p-nitrophenyl phosphate (PNPP), but the presence of a ghost membrane, as a support of the enzyme, affects its kinetic properties. Moreover, calcium ions stimulate and phosphate ions inhibit the PNPPase activity of alkaline phosphatase present in resealed ghost cells. (C) 2002 Elsevier B.V. B.V. All rights reserved.