1000 resultados para Enzimas - Regulação
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Among the sexual hormones the estrogens are receiving major attention due to their biological activity. Such biological response is atributed to the best conformation recognized by their receptors, resulting in maximum responses. The estrogens are also considered responsible for most of disruptor´s effects caused by their presence in aquatic ecosystems. The 17β-estradiol hormone is produced by vertebrates during the reproductive phase of their lives and its presence has been detected in superficial waters. The objective of this study was to evaluate the cause-effect of tilapia exposition to the hormone 17β-estradiol through the analysis of biotransformation enzymes in liver and gills, complemented with the quantification of 17β-estradiol and estrone in water samples collected from fish ponds integrated to swine production. The present study was conducted under laboratory conditions, in a randomized experimental design with three levels of 17β-estradiol (E2) (0, 5, 15 µg L-1), with three replicates. After 7 days of exposure time, liver and gills were extracted to analyze three isoforms of cytochrome P450: EROD, BROD, PROD and the activity of Glutathione S-Transferase (GST). The results showed that the EROD activity (CYP1A), normally induced by the metabolism of aromatic compounds, did not present statistical differences among the treatments exposed to E2, what means that the hormone did not induce isoform 1A in fish under these particular experimental conditions. PROD activity was significantly altered in both concentrations, by means of 5 and 15 µg L-1, when compared to control. This result can indicate an important role of PROD on the metabolism of E2 present in water. Regarding to the BROD activity, it could be observed differences statistically significant between control and both groups of treatments. Two or more CYP isoforms can contribute to the metabolism of the same compound, what makes BROD a candidate as a next bioindicator of the exposure to E2 in aquatic ecosystems. Analysis of variance could confirm the effect of E2 statistically significant on the GST activity in liver tissues with >90% of significance (Prob>F = 0.0753). Furthermore, it was possible to observe that the values of GSTs activities in liver and gills in both, control and treatments, follow a tendency, that means, enzymatic activity in gills increase as the increasing of the activity in the liver tissues. In this study, the 17β–estradiol was found in measurable concentrations in three sampled points, and these values were similar to the findings of other authors at different locations in Brazil. In addition, those values are much higher than the minimum concentration that presented observable effects (10 ng L-1).
Simulação computacional da extração líquido-líquido fracionada de enzimas para produção de biodiesel
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Liquid-liquid extraction is utilized for purification of biomolecules by Aqueous Biphasic Systems (ABS), since this process does not damage the biotechnological potential of these compounds. In this work, using the free software Scilab®, the fractionated liquid-liquid extraction was studied aiming a lipase (target enzyme) partition in a water + PEG + DEX system. Lisozime was considered as contaminant. As computer simulations has been extensively used when a first estimation of technical feasibility of process is desired, this work demonstred that the system is viable for recovery the 80 % till 90 % the target enzyme, but should be noted that the trial aimed only the fractionation of the enzyme target of a contaminant, not its concentration, which should be done by another process.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Enzyme stabilization is one critic point in basic and applied enzymology. The increasing interest in applying enzymes in industrial processes has fostered the search for biocatalysts with new properties or extreme stability. Enzyme stabilization can be achieved by different methods: isolating enzyme variants from organisms living in appropriate extreme environments (extremozymes), by protein engineering, chemical modification, use of additives, immobilization. This brief review aims to give a better understanding of those methods employed for enzyme stabilization.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Zootecnia - FCAV
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Biotecnologia - IQ
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Pós-graduação em Engenharia Elétrica - FEIS
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This article presents a reflection on the historical aspects and legislation on Distance Learning (DL). For this, a bibliographic and documentary research was performed with the goal of raising the necessary notes for discussion. The text begins with the characterization of the current society, the Information Society, which supports the modern distance education, which uses information and communication technologies (ICTs) to establish the process of learning teaching. Five stages of the EAD are identified. Later, the Brazilian legislation concerning the DL is punctuated, starting with the passage by Article 80 of the Guidelines and Bases Law-LBD (Law 9394/96) along with the critical analysis of Decree 5,622/05. Finally, in the final considerations is discussed the negative image that the DL carries by the Brazilian population and obstacles in the existing rules that hinder the democratization of access to education that aims DL.
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Our main concern was to investigate the forms and rationalities implicit in the social regulation/autonomy of the management processes of learning, historically established in the 1971 through 2002 educational reforms, via assessment guidelines of school performance in the state of São Paulo. We used a socio-historical approach, relying on speeches and official documents as our primary source and on studies and research work about teacher assessment and performance as secondary sources. As central categories we considered continuity and rupture in the patterns and mechanisms of social regulation/autonomy of educational work. The results help to clarify how educational policies, instituted in contexts of social reproduction/transformation, influence the management of educational processes within the school.
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Temperature is certainly one of the major factors that affect biochemical and physiological processes. So, the investigation of how animals regulate body temperature (Tb) and respond to changes in ambient temperature is indispensable. There are five thermal states defined up to date that include euthermy, hypo and hyperthermia (forced fall and increase of Tb, respectively), fever and anapyrexia (regulated increase and fall of Tb, respectively). In this review, we present some classic and recent data about thermoregulatory mechanisms involved in those thermal states with special attention directed to anapyrexia, a phenomenon that has attracted the interest of researchers due to its potential therapeutic benefits.
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Pós-graduação em Relações Internacionais (UNESP - UNICAMP - PUC-SP) - FFC
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Abstract This paper discusses the quality of basic education legitimized by the external evaluation and publicized by the Basic Education Development Index (IDEB) - an index that combines the performance of students in the assessment and the school flow, culminating with the establishment of an objective parameter (grade) that aims to reflect the Brazilian educational quality. The arguments are based on the premise that these two elements are incipient to determine the quality of education in the country without taking into account other factors that affect quality, namely: socio-economic and cultural level of the students, teacher training, enhancement of teaching, tangible and intangible working conditions, school management, school infrastructure, supplies, etc. The reflection leading to the debate on the lack of evidence to establish the quality of education travels the ways of the external evaluation in Brazil, the technical rationality of the school management referenced primarily by the IDEB and its governance to achieve the goals determined by this index. The purpose of this essay is to contribute to the current debate on the IDEB as a proposer and mobilizer of policies for the Brazilian public schools.
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Pós-graduação em Biopatologia Bucal - ICT