Comunicação ao BioMicroWorld2007 - Yeast stress enzymes – application of microbiology and bioinformatics for initiate high school students in environmental studies

Abstract

Ciência nas Férias is a work program supported by Science and Technology Foundation (FCT) of Science and Technology Ministry of Portugal which give an opportunity to the high school student’s aproximate to the research scientific work reality, through participation in scientific stages in laboratories of different scientific research institutions. Generally, the stages take place in summer, during scholar holidays. Bearing in mind that it important stimulate high schools students of Portugal for applications of microbiology and bioinformatics in environmental studies, the Institute of Mediterranean Agrarian Sciences (ICAM) and Department of Chemistry of University of Évora are projected in past July a stage, which cover the scope of environmental analysis using simple experiences involving bioinformatics enzymes search, its detection in yeast, as well as, its response to the presence of metal (vanadium-V) in culture medium. We select this theme to emphasize, in one hand, the fact of capacity for adaptation to environmental changes is a universal prerequisite for organism’s survival and evolution and, in other hand, molecular mechanisms of response, repair and adaptation greatly conserved across nature, endows the cell with its essential plasticity to adjust to environmental events, by a process which is termed stress response. It was very grateful for us realise with young students very simple experiments which demonstrate that changes in the environmental conditions, like metal presence in culture medium, starts a genome stress response program in yeast cells, where survival of each cell depends on their ability to adapt to the environmental changes. In this work are involved five high school students from the 10th, 11th and 12th year, with ages ranging from 15 to 17 years old, during one week. The students were integrated in experimental activities of our laboratories during summer holidays. The main goals of this learning activity were to execute a laboratory work which involves the culture of wine yeast S. cerevisiae vinic UE-ME3, a strain isolated from regional wine of Alentejo, belonging to the Enology laboratory collection of Évora University, construct its respective growth curve, and evaluate its stress-response to the presence of a pentavalent salt of vanadium, NH4VO3, using catalase activity as enzymatic marker, having in attention that yeast cells response to stress induced by changes in the environment has been used as a paradigm to study gene regulation. It was also realised bioinformatics search about genome and peptide sequence of catalase, its metabolic role, having in account that understanding yeast gene regulation will help as a model for studies on higher organisms, because these mechanisms are highly conserved, being similar in organisms ranging from yeast to man. In this experimental approach the young students have acquired basic knowledge about care in preparation of materials and culture media for microbiology and environmental experiments, its importance in the reproducibility of results, as well as, capacity to prepare yeast crude, by ultrasonic disrupt, understanding its importance for protein and enzymatic activity determination by spectrophotometry. The obtained results, in this class, namely growth curve, standard calibration curve for proteins and reaction curve for catalase enzymatic activity; gene (CTT 1) and peptide sequences, as well as, metabolic role of catalase, contributes to incentives the young students to use the experimental approach and bioinformatics tools for recover information about molecular stress markers, appealing realisation of environmental studies involving yeast cells as biological model, which illustrates the importance of such experimental application for elucidate metal stress response by eukaryote cells.