Conceptions on protein, sugar and fats : an investigation with students of basic and higher education

A Bioquímica, enquanto campo do conhecimento busca entender os processos químicos que ocorrem nos sistemas biológicos, sendo assim, é de fundamental importância para o entendimento de nossa própria existência. Apesar de ser uma ciência com conceitos muito bem estruturados, fora do ambiente acadêmico encontramos muitos conhecimentos baseados em senso comum, as chamadas concepções alternativas. Por carregarem uma grande conotação simplista como forma de explicar os fenômenos ou preceitos científicos, tais concepções podem se tornar obstáculos para uma aprendizagem significativa. Dessa forma, é necessário que o professor tome conhecimento de tais concepções para que possa repensar a sua prática, (re) construindo-a de acordo com as necessidades de seus estudantes. Nesse sentido, o presente trabalho visa, por meio de um questionário, inventariar as concepções de estudantes de escolas públicas da cidade de Santa Maria, RS. Foram investigados 34 estudantes de Ensino Fundamental (nono ano), 306 de Ensino Médio (1º, 2º e 3º anos) e 36 de Ensino Superior (formandos do Curso de Licenciatura em Química da Universidade Federal de Santa Maria – RS) sobre os conceitos: Proteínas, Açúcares e Gorduras. De modo geral, podemos perceber nas respostas uma grande tendência em considerar as proteínas como substâncias fundamentais para a saúde, muito relacionadas à “energia” e “força”. Por outro lado, açúcares e gorduras, são considerados substâncias ruins e causadoras de doenças e problemas estéticos, o que não deixa de ser verdade, porém, pode indicar que estes estudantes não têm um claro entendimento do papel de tais substâncias para o correto funcionamento e manutenção dos organismos.Biochemistry, as a field of knowledge seeks to understand the chemical processes that occur in biological systems, it is therefore of fundamental importance for the understanding of our own existence. Despite being a science with well structured concepts, outside the academic environment we find many knowledge based on common sense, the so-called alternative conceptions. On carry a large connotation as simplistic way of explaining the phenomena or scientific principles, these concepts may become obstacles to meaningful learning. Thus, it is necessary that the teacher becomes aware of such concepts to help you rethink your practice, (re) building it according to the needs of their students. In this sense, the present work aims, using a questionnaire, survey the conceptions of students from public schools in the city of Santa Maria, RS. Thirty four students from Elementary School (ninth year), 306 of Secondary Education (1st, 2nd and 3rd years) and 36 of Higher Education (Chemistry Licentiate students, from Federal University of Santa Maria - RS) were investigated on the concepts: proteins, sugars and fats. Overall, we can see a big trend in the responses to consider the proteins as key substances for health, closely related to the "energy" and "force." On the other hand, sugars and fats are considered bad substances and disease-causing and esthetic problems, which is nonetheless true, however, may indicate that these students have no a clear understanding of the role of such substances for proper operation and maintenance of organisms

Modulatory effect of diphenyl diselenide in Carioca High- and Low-conditioned Freezing rats

AbstractDiphenyl diselenide ([PhSe]2)is an organoselenium compound that has interesting pharmacological properties, including antioxidant, glutathione peroxidase-mimetic, and neuroprotective effects. The objective of the present study was to investigate the possible modulatory effect of (PhSe)2 in 17th-generation Carioca high-and low-conditioned freezing (CHF and CLF) rats, an animal model of generalized anxiety disorders. (PhSe)2 was administered at three doses (10, 50, and 100mg/kg) in CHF and CLF rats, and their anxiety-like profiles (conditioned freezing patterns) were measured before and 30min after treatment. A significant difference was found in freezing scores between CHF and CLF animals before treatment (t70=12.50, p<0.001). Treatment with (PhSe)2 at 10 and 50mg/kg decreased freezing in CHF rats but significantly increased freezing at 100mg/kg. (PhSe)2 increased freezing in CLF animals at 50 and 100mg/kg (p<0.01). These results indicate that (PhSe)2 exerts both anxiolytic- and anxiogenic-like effects in bi-directional rat lines. Distinct genetic profiles of the CHF and CLF lines may influence biochemical functions and lead to differential responses to aversive situations and various drugs like (PhSe)2

Efeito in vivo e in vitro do HgCl2 e do 2,3-dimercaprol (BAL) sobre a atividade da ALA-D de cérebro, fígado e rim de camundongos adultos

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Brain zinc chelation by diethyldithiocarbamate increased the behavioral and mitochondrial damages in zebrafish subjected to hypoxia

The increase in brain levels of chelatable zinc (Zn) in dysfunctions involving oxygen deprivation has stimulated the treatment with Zn chelators, such as diethyldithiocarbamate (DEDTC). However, DEDTC is a redox-active compound and it should be better evaluated during hypoxia. We use the hypoxia model in zebrafish to evaluate DEDTC effects. The exploratory behavior, chelatable Zn content, activities of mitochondrial dehydrogenases, reactive species levels (nitric oxide, superoxide anion, hydroxyl radical scavenger capacity) and cellular antioxidants (sulfhydryl, superoxide dismutase) of zebrafish brain were assessed after recovery, with or without 0.2mM DEDTC. The increased brain levels of chelatable Zn induced by hypoxia were mitigated by DEDTC. However, the novel tank task indicated that DEDTC did further enhance the exploratory deficit caused by hypoxia. Furthermore, these behavioral impairments caused by DEDTC were more associated with a negative action on mitochondrial activity and brain oxidative balance. Thus, due to apparent pro-oxidant action of DEDTC, our data do not support its use for neuroprotection in neuropathologies involving oxygen deprivation

Editorial: 10 years of Frontiers in genetics: past discoveries, current challenges and future perspectives

3 páginasThis research was supported by the National Institute on Health,grant number R01AG059586, R01AG059586-03S1, and by the University of Connecticut (UConn) Claude D. Pepper Older Americans Independence Center (P30-AG067988). BR is a recipient of a Glenn Award for Research in Biological Mechanisms of Aging. Research in the MR lab is supported by the Canadian Institutes of Health Research (CIHR) Project Grant 202203PJG-482520-CIA-CDAA-111824, CIHR Project Grant 202209PJT-486512-CIA-CDAA-111824, University of Manitoba Collaborative Research Program, Ontario Rett Syndrome Association Hope Fund, Children Hospital Research Institute of Manitoba (CHRIM), and Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant RGPIN2016-06035. Work at JP-T’s lab was supported by CIBER-Consorcio Centro de Investigación Biomédica en Red-(209), Instituto de Salud Carlos III, Ministerio de Ciencia e Innovación.Peer reviewe

Efeitos da cafeina (caf) na habituação intra-sessão e na atividade motora (am) de ratas adultas

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Efeitos da cafeina (caf) na habituação intra-sessão e na atividade motora (am) de ratas adultas

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Saberes construídos e experiências adquiridas no programa de iniciação científica do Colégio Estadual Dom João Becker

O trabalho investiga o processo de iniciação científica em uma escola pública de Porto Alegre/RS. Este processo ocorre desde 2006 com alunos ingressos no ensino técnico de Química e tem se constituído em um fator de motivação para a permanência desses alunos. A iniciação científica neste nível de ensino tem se mostrado um importante instrumento de aprendizagem, uma vez que mobiliza os conhecimentos de diferentes disciplinas para a construção de projetos de pesquisa na área de Química e possibilita aos alunos o aprendizado de métodos de organização e construção do conhecimento. A análise do processo visou a identificar como ele ocorre, quais as dificuldades e qual tem sido seu aproveitamento, por parte dos professores, no processo de ensino e aprendizagem.The work investigates the process of Scientific Initiation in a Public School of Porto Alegre - RS. This process occurs since 2006, with pupils ingressions in Ensino Technician of Chemistry and if has constituted as a factor of motivation for the permanence of these pupils. The Scientific Initiation in this level of education if has shown as important instrument of learning, a time that mobilizes the knowledge of different you discipline for the construction of projects of research in the area of Chemistry and make possible to the pupils the learning of organization methods and construction of the knowledge. The analysis of the process aimed at to identify as it occurs, which the difficulties and as he has been used to advantage, for the professors, in the process education and learning

Involvement of glutamate and reactive oxygen species in methylmercury neurotoxicity

This review addresses the mechanisms of methylmercury (MeHg)- induced neurotoxicity, specifically examining the role of oxidative stress in mediating neuronal damage. A number of critical findings point to a central role for astrocytes in mediating MeHg-induced neurotoxicity as evidenced by the following observations: a) MeHg preferentially accumulates in astrocytes; b) MeHg specifically inhibits glutamate uptake in astrocytes; c) neuronal dysfunction is secondary to disturbances in astrocytes. The generation of reactive oxygen species (ROS) by MeHg has been observed in various experimental paradigms. For example, MeHg enhances ROS formation both in vivo (rodent cerebellum) and in vitro (isolated rat brain synaptosomes), as well as in neuronal and mixed reaggregating cell cultures. Antioxidants, including selenocompounds, can rescue astrocytes from MeHginduced cytotoxicity by reducing ROS formation. We emphasize that oxidative stress plays a significant role in mediating MeHg-induced neurotoxic damage with active involvement of the mitochondria in this process. Furthermore, we provide a mechanistic overview on oxidative stress induced by MeHg that is triggered by a series of molecular events such as activation of various kinases, stress proteins and other immediate early genes culminating in cell damage