Effect of heavy metals, pesticides and pharmaceuticals on yeast's vacuoles as a biomarker for toxic detection

In this study, the effect of different toxic chemicals on Saccharomyces cerevisiae's vacuoles was determined. More precisely, oxidative stress was mediated by pesticides and heavy metals, whereas nonoxidative stress influence was caused by the treatment with pharmaceuticals. Previously, oxidative stress was reported to alter yeast vacuolar enzymes, thus, intracellular vacuoles are assumed to be used as a biomarker to detect the oxidative stresses on yeast. Simultaneously, nonoxidative stress effect was expected to be recognized by vacuoles as well. The feasibility of toxic detection by vacuolar response was evaluated by confocal microscopy after staining the vacuoles with LysoTracker. The results indicate that each chemical has its own optimal concentration at which the signal corresponding to vacuolar response reached the peak without inhibiting the yeast growth. Therefore, this method was confirmed to detect toxic chemicals at their sub-lethal doses. In addition, the minimum response time of vacuoles for different toxic chemicals was also measured.