The present report shows that thymocyte death, induced by glucocorticoids, may be modulated in vivo by ouabain. Young, ten days old, mice injected with 140 mg/kg sodium succcinate of hydrocortisone (HC) intraperitonially (i.p.) displayed, 24 h after the injection, a decrease in thymus size and cellular content, an effect that was magnified when ouabain (OUA) 0.56 mg/kg, i.p. was given 1 h prior to the HC injection. Ouabain per se was not capable of producing these changes. Both HC and the combination OUA plus HC induced the death of immature double positive lymphocytes (CD4+CD8+) whereas CD69+ cells survived both treatments. An increase in annexin positive cells and a decrease in mitochondrial membrane potential, assessed by cytofluorimetry, using the fluorescent dye DiOC6, was observed in thymocytes from HC treated animals indicating apoptosis of these cells. Furthermore, a synergistic effect between OUA and HC was also observed using this parameter. The synergy observed in the thymus of animals treated with glucocorticoids and OUA might occur under stress, when both hormones are released, or in situations when ouabain is administered exogenously in a moment of the circadian cycle when glucocorticoid levels are elevated. However the impact of this effect on the immune response is still unknown.
Apoptotic cell death plays a critical role in immune system homeostasis, and c-myc protooncogene deregulated expression is a component of this programmed genomic response. Pharmacological intervention and modulation of peripheral lymphocytes apoptosis would have important implications. The present results indicate that ouabain, a specific inhibitor of Na+K(+)-ATPase, promotes an increased expression of c-myc mRNA, and induces apoptosis in PHA-stimulated lymphocytes. Furthermore, this ouabain-induced apoptosis cannot be counteracted by the addition of exogenous IL-2.
International specialized literature focused on research in biology education is sadly scarce, especially regarding biochemical and molecular aspects. In this light, researchers from this Centre for Structural Molecular Biotechnology developed and evaluated a three-dimensional educational model named "Building Life Molecules DNA and RNA." The development of the model and its evaluation as a potential tool in the teaching-learning process were based on a pilot study involving 226 learners and teachers. Questionnaires were elaborated, containing simple and objective questions, similar to those used in research on science teaching, to orient the evaluation process. Our results show that the model has high educational potential, aiding participants in their conceptual understanding of these molecular structures and their functions, DNA semiconservative replication, and RNA transcription. In addition, it was observed that this model leads students to critical associations of these concepts with actual scientific themes of molecular biology and biotechnology, such as cloning, transgenic organisms, and the genome.
Abstract:This article aims to describe the most important historical and scientific facts that permitted today's understanding of the structure and functionality of the DNA molecule. We believe that recovering history and divulging it culturally integrates new and old generations to the contemporary society we belong to, facilitating the learning and the understanding about our constitution and functionality, as well as allowing us to speculate about our future, our evolution, the life on our planet, and the focus and course of new research in this scientific area.
Resumo:Este artigo tem o objetivo de relatar os fatos históricos científicos mais importantes que permitiram o entendimento atual da estrutura e funcionalidade da molécula de DNA. Acreditamos que resgatar a história e divulgá-la integra culturalmente novas e velhas gerações à sociedade contemporânea a que pertencemos, facilitando o aprendizado e a compreensão sobre a nossa constituição e funcionalidade, assim como nos permite especular sobre o nosso futuro, nossa evolução, a vida no planeta, e o enfoque e direcionamento de novas pesquisas desta área científica.Endereço para correspondência:
The progress in the areas of molecular biology and biotechnology has been demonstrating the importance of the teaching-learning of those subjects to students and teachers of the elementary and high school as well as to the society in general.In this sense, the Scientific Dissemination Coordination of CBME has as objective contributes for the dissemination and learning of techniques and basic concepts in that area of the knowledge, in order to awake in the public the scientific interest and the critical sense related to these advances.With the goal to offer elements for the elaboration of activities addressed to science teachers of elementary and high school, a survey of their conceptions on science and biotechnology was made. A questionnaire was applied to 30 teachers that participated in updating courses and training, being that 13 teachers belonged to the region of São Carlos city (SP), 8 belonged to the region of Campinas city (SP) and 9 belonged to Fortaleza city (CE).The questionnaire was applied to the teachers in the beginning of the courses and it was composed of different types of questions, which allowed capturing their personal reflections about science, their knowledge on basic concepts of cell and molecular biology, and their opinions about the applications of the biotechnology.In the analysis of the question What you think about using the modern biotechnology in the production of foods to increase its protein content, in order to turn it larger or to change its taste?, 57% of the teachers agreed partially that this application is useful for the society, 52% agreed totally that the application is morally acceptable while 70% totally disagree as for the encouragement of this application.Some conflicts presented in the registered answers reflect, in certain way, the conflict shown by the academic and scientific communities, as for the ethical aspects of some applications such as transgenic foods, genetic manipulation in animals and the possibility of human cloning.
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