Navegando por Palavras-chave "Lactase"

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    Controlling the molecular architecture of lactase immobilized in Langmuir-Blodgett films of phospholipids to modulate the enzyme activity
    (Elsevier Science Bv, 2017) Ayoub, Fabio de Paula [UNIFESP]; Caseli, Luciano [UNIFESP]
    In this present work, the adsorption of the enzyme lactase onto Langmuir monolayers of the phospholipid dimyristoylphosphatidic acid (DMPA) was investigated and characterized with surface pressure-area isotherms, surface potential-area isotherms and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). The adsorption of the enzyme at the air-water interface expanded the lipid monolayer and increased the film compressibility at high surface pressures. Amide bands in the PM-IRRAS spectra were identified, with the C-N and C=O dipole moments lying parallel to the monolayer plane, revealing that the structuring of the enzyme into beta-sheets was kept in the mixed monolayer. The enzyme-lipid films were transferred from the floating monolayer to solid supports as Langmuir-Blodgett (LB) films and characterized with fluorescence spectroscopy and atomic force microscopy. The catalytic activity of the films was measured and compared to the homogenous medium. The enzyme accommodated in the LB films preserved more than 80% of the enzyme activity after 20 days, in contrast for the homogeneous medium, which preserved less than 60% of the enzyme activity. The method presented in this present work not only allows for an enhanced catalytic activity toward lactose, but also can help explain why certain film architectures exhibit better performance. (C) 2016 Elsevier B.V. All rights reserved.
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    Efeito Da Chia ( Salvia Hispanica L) Sobre Parâmetros Metabólicos E Inflamatórios No Diabetes Mellitus, Em Camundongos
    (Universidade Federal de São Paulo (UNIFESP), 2017-11-30) Oliveira, Cinthia Romeika De [UNIFESP]; Silveira, Vera Lucia Flor [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Introduction and Objectives: Diabetes mellitus (DM) is a chronic disease, characterized by hyperglycemia, which may be caused by the absence or deficient of insulin secretion or peripheral resistance to this hormone. As a consequence of this alteration, the adipose tissue of individuals with type 2 DM (DM2), presents high rates of lipolysis, aggravating the existing insulin resistance. Several studies have shown the importance of omega-3 polyunsaturated fatty acids (PUFAs w-3) as complementary therapy in the treatment of chronic diseases, including DM. Studies have shown that these PUFA decrease the inflammatory process and may improve insulin resistance. chia seeds, which has the vegetable oil with the highest concentration of PUFAs w-3, known until now, has been widely used by the population for reduction of weight, cholesterol and triglyceride, and also prevention of diabetes and cardiovascular diseases. However, the scientific papers which study these relations are few and still quite contradictory. This study aims to analyze the preventive effect of dietary supplementation with chia oil on metabolic and inflammatory parameters in mice submitted to the DM2 model, induced by hyperlipidic diet and streptozotocin (STZ). For this, we used male C57bl / 6 mice, divided into three groups: control (C), diabetic (D) and diabetic treated with chia (DC). The animals in group C received a normolipidic diet for 6 weeks and the animals in groups D and DC received a hyperlipidic diet and daily doses of water (D) or chia oil (DC). At the end of the third week of feeding, animals in groups D and DC were induced to partial insulin deficiency by 1 dose (45mg / kg) of STZ during 5 consecutive days. At the end of the sixth week the mice were euthanized, blood, liver and adipose tissues removed. Results and Conclusions: Preventive treatment with chia oil promoted beneficial effects such as decrease body mass gain without modifying caloric and energy consumption, reduction of visceral fat, lipolysis and adipocyte volume of the epididymal tissue and increase of HDL- c. However, although this treatment partially improved glucose tolerance, it did not improve insulin resistance. It appears that the beneficial effects induced by chia in lipid metabolism were not sufficient for the improvement of insulin resistance required for the treatment of DM2.
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    Interação da enzima Beta-galactosidase em filmes lipídicos e poliméricos de Langmuir e Langmuir-Blodgett
    (Universidade Federal de São Paulo (UNIFESP), 2019-11-29) Araujo, Felipe Tejada [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    In this work we studied the interaction of β-galactosidase in Langmuir and Langmuir-Blodgett (LB) films of stearic acid (HSt) and poly (9,9-dioctylfluorene) -co-thiophene polymer (PDF-TF). The lipid was spread at the air-water interface forming Langmuir monolayers and the enzyme was inserted into the supporting aqueous phase of the lipid monolayer. The adsorption of the enzyme to the monolayer was studied by surface-area pressure isotherms, surface-area potential isotherms, Brewster angle microscopy and vibrational spectroscopy. The mixed monolayer (lipid / enzyme / polymer) was transferred to solid supports by the LB methodology and characterized by luminescence spectroscopy, vibrational spectroscopy, and atomic force microscopy, indicating the presence of the polymer and the enzyme. The enzymatic activity of immobilized lactase as LB film was evaluated against lactose hydrolysis was evaluated with UV-visible spectroscopy. In conclusion, the enzyme can be inserted into lipid films, partially maintaining its secondary structures and altering the morphology of LB films. Catalytic activity could be maintained at up to 60% of activity after one month after transfer to LB film, which makes the system viable for future applications in lactose biosensors.
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    Interação da enzima lactase em filmes fosfolipídicos de Langmuir e Langmuir-Blodgett: possível aplicação para biossensores para lactose
    (Universidade Federal de São Paulo, 2017-10-06) Ayoub, Fabio de Paula [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    In this work the interaction of the enzyme lactase in Langmuir and Langmuir-Blodgett (LB) films of the phospholipid dimyristoylphosphatidic acid (DMPA) was studied. The phospholipid was spread at the air-water interface forming Langmuir monolayers, and the enzyme was inserted into the aqueous subphase that supported the lipid monolayer. The adsorption of the enzyme to the monolayer was studied by surface pressure-area isotherms, surface potential-area isotherms, Brewster angle microscopy, and by vibrational spectroscopy. The mixed monolayers phospholipid + enzyme was transferred to solid supports by the LB methodology and characterized by luminescence spectroscopy, vibrational spectroscopy, atomic force microscopy and nanogravimmetry by quartz crystal microbalance. The enzymatic activity of the lactase immobilized as LB film was evaluated and compared to the hydrolysis of lactose to glucose and galactose using UV-visible spectroscopy. As conclusion, the enzyme can be inserted into the lipid films, maintaining partially its secondary structures, and altering the morphology of the LB films. The catalytic activity could be maintained up to 84% of the activity in relation to the homogeneous medium, which makes the system feasible for future applications in lactose biosensors.