Chemicals binding to membrane receptors may induce events within the cell changing its behavior. Since these events are simultaneous and hard to be understood by students, we developed a computational model to dynamically and visually explore the cAMP signaling system to facilitate its understanding. The animation is shown in parts, from the hormone-receptor binding to the cellular response. There are some questions to be answered after using the model. The software was field-tested and an evaluation questionnaire (concerning usability, animations, models, and the software as an educational tool) was answered by the students, showing the software to be a valuable aid for content comprehension.

Avaliou-se o efeito de concentrações inferiores à mínima inibitória (50, 25 e 12,5% do MIC) de nitrofurantoína, estreptomicina e eritromicina sobre velocidade específica máxima de crescimento (µmax) e velocidade específica de acúmulo de polímero (µPHB) em Alcaligenes eutrophus, considerada resistente a estes antimicrobianos. Nitrofurantoína modificou bastante µmax, mesmo com 50% MIC. Estreptomicina afetou moderadamente e eritromicina não afetou µmax. Quanto à produção de polímero, nitrofurantoína alterou fortemente µPHB quando se empregou 50% MIC.

This work evaluated the influence of nitrofurantoin, erythromycin and streptomycin at 50, 25 and 12,5% of the minimal inhibitory concentration (MIC) on maximum specific growth rate (µmax) and specific polymer accumulation rate (µPHB) of Alcaligenes eutrophus, considered resistant to those antimicrobials. Nitrofurantoin strongly affected µmax even at 50% MIC. Streptomycin moderately affected µmax only at 50%MIC. Nitrofurantoin showed the most harmful effect on µPHB when 50% MIC was applied and erythromycin was not harmful.

Though Free Radicals is one of the most frequently explored scientific subjects in mass communication media, the topic is absent of many Biochemistry introductory courses, especially those in which the students do not have a good chemical background. To overcome this contradictory situation we have developed a software treating this topic in a very simple way. The software is divided in four sections: (1) definition and description of free radicals, (2) production pathways, (3) mechanism of action and (4) enzymatic and non enzymatic protection. The instructional capacity of the software has been both qualitative and quantitatively evaluated through its application in undergraduate courses. The software is available in the INTERNET at the site: http://www.unicamp.br/ib/bioquimica/ensino.