Trichoderma is one of the fungi genera that produce important metabolites for industry. The growth of these organisms is a consequence of the nutritional sources used as also of the physical conditions employed to cultivate them. In this work, the automated Bioscreen C system was used to evaluate the influence of different nutritional sources on the growth of Trichoderma strains (T. hamatum, T. harzianum, T. viride, and T. longibrachiatum) isolated from the soil in the Juréia-Itatins Ecological Station (JIES), São Paulo StateBrazil. The cultures were grown in liquid culture media containing different carbon-(2%; w/v) and nitrogen (1%; w/v) sources at 28ºC, pH 6.5, and agitated at 150 rpm for 72 h. The results showed, as expected, that glucose is superior to sucrose as a growth-stimulating carbon source in the Trichoderma strains studied, while yeast extract and tryptone were good growth-stimulating nitrogen sources in the cultivation of T. hamatum and T. harzianum.

Resumo:Aulas práticas são ambientes de aprendizagem potenciais para o desenvolvimento de uma série de habilidades. Este artigo apresenta a proposta de uma atividade prática, que envolve o desenvolvimento de habilidades cognitivas e de instrumentação laboratorial, em que o conteúdo sobre aminoácidos e proteínas de uma disciplina de Bioquímica é trabalhado em um ambiente de investigação científica. Em grupos, os estudantes são estimulados a resolver um problema previamente proposto, tendo autonomia para elaborar uma estratégia experimental. Toda a atividade é estruturada numa abordagem de integração da teoria e prática, em que se objetiva buscar informações sobre amostras desconhecidas, direcionando a prática para a observação crítica e criativa do processo experimental. Palavras-chave: aulas práticas, aulas de laboratório, aminoácidos, proteínas, atividades investigativas Abstract:Practical lab classes are potential learning environments for the development of a series of skills. This article presents the proposal of a practical activity that involves the development of cognitive and laboratory instrumentation skills, in which the amino acids and proteins contents of a discipline of Biochemistry is worked on a scientific research environment. In groups, students are encouraged to solve a previously proposed problem, having autonomy to formulate an experimental strategy. The whole activity is structured in an approach that integrates theory and practice, which aims at seeking information on unknown samples, focusing the practice on the critical and creative observation of the experimental process.

Recebido em 28/2/08; aceito em 17/9/08; publicado na web em 15/4/09 BUFFERING-SYSTEMS: A THEORETICAL AND PRACTICAL DIDATIC APPROACH. Courses with practical and theoretical classes are potentially didactic structures for the development of motor and complex cognitive skills when operated in an integrated manner. When worked aligned, theory and practice enable a clearer view of the issue, opening scope for introducing concepts from other disciplines and for the development of lab skills. This paper presents a methodology for biochemistry labwork that promotes the teaching of the buffering systems contents together with to the development of scientific research practice concepts in an interdisciplinary perspective that integrates theory and practice.

External representations (ERs), such as diagrams and animations have an important role in biochemistry education; it allows the understanding of abstract concepts and phenomena. Visual literacy (the interpreting, thinking and learning capacities using images), has been pointed out as the main cause of student's difficulties to comprehend ERs. To evaluate the visual skills on metabolic pathways, a computer based exam was designed and applied to the undergraduate Biology students at Unicamp. The exam was based on questions that require ERs understanding . The simbology adopted is the most often used in biochemistry textbooks. The target concepts evaluated were defined previously, and clustered in categories to define the visual literacy skills to be evaluated. The exam was supported by both multiple choice questions and interactive questions such as "click and drag", and taken by 83 students. The analysis was performed using the average scores of each question. The lowest scored questions involves: 1) the identification of every substrate and product in a given metabolic pathways; 2) the understanding of the dynamics of the cyclical pathways diagrams; 3) to drag and drop icons to build a reaction diagram; 4) the recognition of compounds involved in the oxidation-reduction reactions. These results pointed out some of the major difficulties that the students have on interpreting ERs.

Biochemistry labworks are fundamental to both the instrumentation and for the establishment of important concepts. The labworks of Basic Biochemistry (BB280) for Biology students at UNICAMP have gone through several improvements. The labworks are now structured from simple activities to more complex ones, and aimed to the student's autonomy development in the experiments planning and execution over the teaching semester. The first practical activity is on buffer systems, and it is based on the confrontation of a theoretical model with the lab experiments results. First of all, the students simulate a Titration in a computational environment, where students lay a theoretical model from their knowledge. In the theoretical model the buffer parameters are set according to the teacher instructions, and the experiment conditions are also set and tested. The simulation results are used for planning the experiment and to compare with the experimental ones. After having the simulations concluded and having the experiment planned the students perform the in lab Titration with the parameters established in the simulation. The results obtained by students are presented in a report. We analyzed the reports from 76 BB280's students in 2007(night class and day class). The students identified as the main causes of the discrepancy between theoretical and experimental data: 1) experimental errors, related to the lack of technical skill 2) limitation of equipment used 3) unexpected behavior of the substances used. In addition to the theoretical content related to labwork, the confrontation between the simulation and experimentation provided the students with ability to identify the main aspects of which can influence the quality of the data obtained.

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