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Estudo da expressão de lipase BTL2 de Bacillus thermocatenulatus em E. coli recombinante
(Universidade Federal de São Carlos, 2009-04-03) Escallón, Ana María Vélez; Giordano, Raquel de Lima Camargo; https://lattes.cnpq.br/0003899410308014
Using recombinant DNA techniques, the lipase BTL2 gene of Bacillus thermocatenulatus was cloned in E. coli BL321 under control of the strong temperature-inducible λPL promoter. It was investigated, initially, in this work, the influence of different variables in cell growth and expression of lipase BTL2 by recombinant E. coli, through experiments performed in agitated flasks with LB medium. First, it was studied the influence of temperature of growth (between 27 ° C and 34.2 °C) and heat shock temperature (between 37.8 °C and 46.2 °C) in the expression of lipase BTL2 by E. coli recombinant, using statistical design of experiments. The results of this study, where the shock was performed in the early exponential phase, indicated as the best Tcresc = 27 °C and Tchoque = 45 °C, yielding cellular concentration of 0.6 g dry weight / L and enzyme activity of 121.000 U/g.wet.cel. Then, it was investigated the influence of the growth phase of the microorganism at the shock, through cultures with Tcresc = 27 °C and Tchoque = 45 °C, the results of these experiments showed how heat shock condition at the end of exponential phase, resulting in activity of 258.000 U/g.wet.cel It investigated the influence of different initial concentrations of glucose in the medium on cell growth and expression of the enzyme. The best results were obtained from cell mass with 10 g/L glucose and μmax = 0,16 h-1, Yx/s = 0,19 g/g, resulting in 1.2 g / L dry cel, enzymatic activity of about 250.000 U / g.wet.cel. Lower concentrations of glucose and higher concentrations led to smaller cell, but did not affect enzyme activity in the final. Based on previous cultures of E.coli were conducted simulations to calculate the best condition for feed-batch. The experimental test was performed with 10 g/L glucose at the beginning of cultivation, Tcresc = 30 °C, Tchoque = 45 °C. In this test, we were able to achieve 15 g/L dry.cel μmax = 0,38 h-1 with enzyme activity of 231.000 U/g.wet.cel, with resulting in 100 times more enzyme in this test than in cultivation in shaker in the best condition. The results of the simulation, obtained using model of Monod, predicted quite well those obtained experimentally. There was no significant accumulation of organic acids and all aminoacids consumed by the moment of shock. From the heat shock, those who were not exhausted with concentration remained constant. The enzyme produced in the test batch was recovered by breaking the cells in a French press to obtain with this methodology 272.000 U/g wet cells, whereas the results of the samples, which were disrupted by sonication resulted in much lower value. Was then investigated the efficiency of the protocol of sonication that was being used, by subjecting the cells to successive rounds of sonication. The results showed that actually the first cycle only 50% of the enzyme was released, indicating that the maximum production achieved was actually around 462.000 U/gcél.úmida. Study characterization of enzyme kinetics showed that the temperature of maximum activity is 65 °C with activation energy equal to 142.3 kJ/mol. Study of stability in solvent showed that the enzyme retains activity in the presence of 2- propanol.
Projeção e desamparo : filosofia, religião e teoria psicanalítica em Sigmund Freud
(Universidade Federal de São Carlos, 2009-04-03) Conte, Fabiano Roberto Sales; Monzani, Luiz Roberto; https://lattes.cnpq.br/2036732603638197; https://lattes.cnpq.br/7720446592652597
One of the most important movements of what we call enlightenment concerns the analysis of the religious phenomenon. Some authors who lived under the aegis of this historical period, as Hume and Feuerbach, adopted a very similar semantics for the construction of their explanatory discourses when dissecting religious belief issues, as well as its motivations and the involved psychical processes. The fear as a cause and the projection as a mental process are important elements in this construction. When Freud who was a reader of both authors and is considered one of the last enlighteners writes some of his texts about the religious phenomenon specifically Totem and Taboo and The Future of an Illusion he ends up making use of explanatory resources which refer to thatphilosophical tradition. The terms which will appear in Freud are helplessness(Hilflosigkeit) and projection(Projektion). These concepts, however, despite of their extreme operativity within the explanatory structure of the religious phenomenon, do not appear for the first time in these cultural texts: they have been part of the history of freudian psychoanalysis for a long time, and have their meaning laboriously built during a long course of development of the theory. The aim of this paper is, thefore, to unravel the paths taken during the elaboration of the concepts of helplessness and projection, so then their real meanings can present themselves when a text on religion is read that will not only allow a more accurate comprehensionabout it but will also demonstrate how the Freudian concepts are developed, both internally in psychoanalysis and in its contact with other forms of construction of knowledge such as philosophy.
Potencial osteogênico in vivo de uma nova vitrocerâmica bioativa (Biosilicato®)
(Universidade Federal de São Carlos, 2009-04-03) Granito, Renata Neves; Oishi, Jorge; https://lattes.cnpq.br/1417328590472858
Bioactive materials have the ability to bond and to integrate with bone tissue by forming a biologically active bonelike apatite layer, which has chemical and structural properties equivalent to the mineral phase of living bone. This process is determined by chemical reactions, whose products also influence the attachment, the proliferation, the differentiation and the mineralizing capacity of bone cells. Cellular responses contribute to the bioactive behavior, which is known for being higher in glass materials. However, as low mechanical properties are also inherent characteristics of glasses, researchers from Federal University of Sao Carlos were stimulated to develop nucleation and growth thermal treatments for the obtainment of the Biosilicate®, a fully-crystallized bioactive glassceramic of the quaternary system P2O5-Na2O-CaO-SiO2. Although a high in vitro osteogenic potential of this novel glass-ceramic has been previously demonstrated, its in vivo effects have not been investigated yet. To contribute to this knowledge, two studies were developed. The first one aimed to investigate the in vivo biological performance of Biosilicate® in bone defects of rat tibias, by means of hystomorphometric and biomechanical analyses 20 days after the surgical procedure. This study revealed that the fully-crystallized Biosilicate® has good bone-forming and bone-bonding properties. Hence, the second study aimed to compare the kinetics of the bone reactions to two different granulometric distributions of this novel glass-ceramic. Although they were both efficient for bone formation, smaller-sized particles of Biosilicate® showed partial reabsortion, which was accompanied by a more pronounced osteogenic activity within the period of time studied. Since positive results were obtained, the search for scaffolds that could serve as supports for the guided bone regeneration had started. A third study preliminarily evaluated cell culture and cocultures in porous structures made of Biosilicate® and of other chemical compositions that were specifically developed for this purpose. The findings suggest that, when in adjusted conditions, the scaffolds can create favorable cellular responses for bone tissue engineering purposes. Taken togheter, these studies point to a promising potential and provide directives for the use of Biosilicate® in bone regenerative processes.