Atividades de peroxidase e polifenoloxidase durante o armazenamento pós - Colheita de yacon (polymnia sonchifolia poep & endl)

The purpose of this study was to investigate the peroxidase and polyphenoloxidase activities during the refrigeration at 4oC of yacon tuberous roots with and without polyethylene packing and compared with untreated roots at regular conditions. It was concluded that refrigeration treatment maintains a low activity of these enzymes and keeps good appearance of the roots.

Localization of peroxidase activity in blood mononuclear phagocytes in pacu fish (Piaractus mesopotamicus)

The localization of peroxidase activity in different cell regions is used as a criterion for classifying the stage of maturity of mammalian mononuclear phagocytes, with a positive peroxidase reaction indicating the presence of monoblasts, promonocytes, monocytes, and macrophages. Peroxidase activity was observed ultrastructurally in the circulating blood of pacu fish (Piaractus mesopotamicus), identifying monoblasts, promonocytes, monocytes, and macrophages. These observations suggest that differentiation of mononuclear phagocytes occurs in the blood circulation of fish, whereas in mammals, monoblasts and promonocytes are detected in bone marrow, with only monocytes detected in circulating blood and differentiation into macrophages occurring in other body compartments.

Peroxidase enzyme (EC.1.11.1.7) activity as an indicator of water stress in sweet pepper plants

The present work was carried out at the Faculdade de Ciências Agronômicas - UNESP, Botucatu, SP. The purpose of the study was to evaluate the physiological and biochemical behavior of sweet pepper (Capsicum annuum L.) plants under different soil water availability conditions and the efficiency of the peroxidase (EC. 1.11.1.7) activity as an indicator of water stress in plants. Sweet pepper plants were grown for 230 days after transplanting of seedlings. The experiment was arranged in a completely randomized experimental design with 4 treatments, two irrigation managements (50 and 1500 kPa) and two soil surface managements (presence or absence of black polyethylene covering), and six replications. Physiological activities, such as stomatal transpiration and resistance to water vapor diffusion, were evaluated, as well as biochemical activities, such as peroxidase activity and total soluble protein in foliar tissues. It was observed that soil water availability may lead to physiological and biochemical alterations in plants. Successive water stress cycles may promote the development of characteristics responsible for improving the plant tolerance to periods of low water availability. The peroxidase enzyme activity showed to be an efficient indicator of water stress in sweet pepper plants.

Peroxidase activity as an indicator of water stress in sweet pepper plants

The purpose of the study was to evaluate the physiological and biochemical behavior of sweet pepper (Capsicum annuum L.) plants under different soil water availability conditions and the efficiency of the peroxidase (EC. 1.11. 1.7) activity as an indicator of water stress in plants. The experiment was carried out at the Faculdade de Ciências Agronômicas UNESP, Botucatu, SP. Sweet pepper plants were grown for 230 days after transplanting of seedlings and arranged in a completely randomized experimental design with 4 treatments, two irrigation managements (50 and 1500 kPa) and two soil surface managements (presence or absence of black polyethylene covering), and six replications. Physiological activities, such as stomatal transpiration and resistance to water vapor diffusion, were evaluated as well as biochemical activities, such as peroxidase activity and total soluble protein in foliar tissues. It was observed that soil water availability may lead to physiological and biochemical alterations in plants. Successive water stress cycles may promote the development of characteristics responsible for improving plant tolerance to periods of low water availability. The peroxidase enzyme activity showed to be an efficient indicator of water stress in sweet pepper plants.

Efeito de poliaminas exógenas no crescimento inical in vitro e nos teores de fenóis, poliaminas e atividade da peroxidase em Aloe vera (L.) Burm.

Lateral shoots of the Aloe vera (L.) Burm. cultivated in vitro, without addition vegetal regulators, for 90 days, were inoculated in MS culture-medium, containing or not spermine and/or spermidine. After 30 days of cultivation, the plants were submitted to biochemical analysis together with micropropagated plants - that were under in vitro cultivation for 90 days - (denominated as characterization), and matrix plants (in vivo). The levels of free polyamines, total phenols, total flavonoids, and the activity of peroxidase were evaluated in the biochemical analyses. The exogenous application of spermidine have promoted large number of shoots. Spermidine and spermine have promoted, when associated, an increase in the number of shoots as well as an increase of the contents of putrescine and and flavonoids. The putrescine has presented the most significant alterations, enabling to be utilized as marker of morphogenesis in the micropropagated Aloe vera. Tissues under active growth have presented high activity of peroxidase as well as those with greater rate of oxidation. In these tissues, there were noticed also higher contents of total flavonoids, indicating the need of antioxidative compounds. The action of polyamines jointly tseemed to be benefic for the shooting of micropropagated Aloe vera.

An optimised electrochemical biosensor for the label-free detection of C-reactive protein in blood

C-reactive protein (CRP) is an acute phase protein whose levels are increased in many disorders. There exists, in particular, a great deal of interest in the correlation between blood serum levels and the severity of risk for cardiovascular disease. A sensitive, label-free, non-amplified and reusable electrochemical impedimetric biosensor for the detection of CRP in blood serum was developed herein based on controlled and coverage optimised antibody immobilization on standard polycrystalline gold electrodes. Charge transfer resistance changes were highly target specific, linear with log. CRP. concentration across a 0.5-50. nM range and associated with a limit of detection of 176. pM. Significantly, the detection limits are better than those of current CRP clinical methods and the assays are potentially cheap, relatively automated, reusable, multiplexed and highly portable. The generated interfaces were capable not only of comfortably quantifying CRP across a clinically relevant range of concentrations but also of doing this in whole blood serum with interfaces that were, subsequently, reusable. The importance of optimising receptor layer resistance in maximising assay sensitivity is also detailed. © 2012.

Evaluation of the interactions of DNA with the textile dyes Disperse Orange 1 and Disperse Red 1 and their electrolysis products using an electrochemical biosensor

A disposable pencil graphite electrode modified with dsDNA was used in combination with square wave voltammetry in order to evaluate the interaction of DNA with the textile dyes Disperse Orange 1 (DO1) and Disperse Red 1 (DR1), and with the products of their electrolysis. Significant changes in the characteristic oxidation peaks of the guanine and adenine moieties of immobilized dsDNA were observed after incubation of the modified electrode for 180 s in solutions of the dyes in their original forms. The same was observed using the electrolysis products obtained by oxidation and reduction conversions. The oxidation peak currents of the guanine and adenine moieties decreased when the concentrations of DO1 and DR1 were increased up to 5.0 × 10 -6 and 1.0 × 10-6 mol L-1, respectively; the signal decreases were more pronounced after interaction with the oxidized dyes, compared to the reduced compounds. The interactions between DNA and DO1, DR1, and the electrolyzed dyes were further investigated by UV-vis spectrophotometry in solution, and different effects such as hypochromism and hyperchromism were observed in the resulting DNA spectra. The investigated interactions showed clear evidence of changes in the DNA structure, and suggested a predominant intercalation mode leading to damage in the biomolecule. © 2013 Elsevier B.V.

Quantification of methomyl levels in cabbage, tomato, and soya milk using a renewable amperometric biosensor

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

Switchable biosensor controlled by biocatalytic process

The poly(dimethylamino methacrylate) (PDMAEMA) brush-modified indium tin oxide (ITO) electrode was used to test the switch properties of interfacial activity caused by bioelectrochemical signals. The swelling of the polymer brushes increased when the medium's pH changed from alkaline to acid after glucose was added to the system. A pH change generated in situ by means of biocatalytic reactions enabled bioelectrocatalytic interface's reversible activation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Glutathione and glutathione peroxidase expression in breast cancer: An immunohistochemical and molecular study

The use of prognostic markers for breast cancer allows therapeutic strategies to be defined more efficiently. The expression of glutathione (GSH) and glutathione peroxidase (GPX) in tumor cells has been evaluated as a predictor of prognosis and response to cytotoxic treatments. Its immunoexpression was assessed in 63 women diagnosed with invasive ductal carcinoma in a retrospective study. The results showed that high GSH expression was associated with tumors negative for the estrogen receptor (ER) (P<0.05), and GPX expression was associated with tumors negative for the progesterone receptor (PR) and patient mortality. Focusing on the 37 patients who received adjuvant chemotherapy/radiotherapy (Group I), high expression of GPX was associated with a high rate of patient mortality (P<0.05). The 19 patients who received only adjuvant chemotherapy (Group II) showed high expression of GSH in relation to metastasis (P<0.05). In addition, high levels of GPX expression were significantly associated with a shorter overall survival (P<0.05). To confirm this, the expression of precursor genes of GSH [glutamate cysteine ligase (GCLC) and glutathione synthetase (GSS)] and the GPX gene was analyzed using quantitative PCR in cultured neoplastic mammary cells treated with doxorubicin. Doxorubicin treatment was able to eliminate tumor cells without alterations in the gene expression of GSS, but led to underexpression of the GCLC and GPX genes. Our results suggest that high levels of GPX may be related to the development of resistance to chemotherapy in these tumors, response to treatment and the clinical course of the breast cancer patients.

Detecção do gene de peroxidase em sementes de soja pela reação da polimerase em cadeia (PCR)

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

Avaliação da capacidade antioxidante de frações orgânicas do cogumelo Agaricus blazei Murril e purificação parcial de peroxidase e polifenoloxidase

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Isolamento, purificação e caracterização da peroxidase de yacon (Smallanthus sonchifolius)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Imobilização de peroxidase em filme de titânio

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudos bioquímicos de tegumento de soja brasileira: isolamento, purificação e caracterização de peroxidase com guaiacol como substrato

Pós-graduação em Biotecnologia - IQ