Metals, environment and life interference of vanadium in living systems and their contextualization in teaching experimental sciences

Abstract

The ammonium metavanadate (V + 5), widely used in chemical industry is a toxic compound which is involved in several cases of enzyme inhibition. The alkaline phosphatase (ALP) a zincglycoenzyme implicated in cell growth and apoptosis can be affected by the presence of metals like vanadium. The main objective of this study was to interest young students to the toxicity of metals, exploring the effects of vanadium on the ALP activity, using Saccharomyces cerevisiae as biological model. This activity was developed by a pilot group of students from Dom Manuel Martins high school of Setúbal, Portugal, which follow the yeast growth at 640nm and obtained cell extracts from S. cerevisiae growing at 28 ◦C in YPD medium (glucose 2% (w / v)) in absence and presence of 25 or 75mM NH4VO3, for the quantification of proteins at 720nm by Lowry’s method and ALP activity determination at 405 nm, using pNPP as substrate. The young people observed a growth inhibition of yeast cells exposed to vanadium as well as a decrease of total proteins and ALP activity level, facts which put in evidence a sharp toxicological effect of vanadium in eukaryotic cell. The average score obtained before and after the experimental activity (41%) and (63%), respectively, using the same set of questionsproblem, revealed an overall positive performance of skills developed by students, in the scope of metals toxicological effects in eukaryote cells. In more detail, it was also observed a positive and significant effect in each experimental phase (p < 0.05), before and after the development of the action. The assessment of skills developed by students showed an improvement of their compliance level, thereby acquiring a significant learning. The results for the opinion survey showed that most respondents classified the activity and its difficulty degree as good.