Saccharomyces cerevisiae as a biological model to study microbial responses to copper and chromium stress

Abstract

To understand the aspects of how organisms cope with copper and chromium stress, Saccharomyces cerevisiae was used as a model. To achieve this purpose, Scanning Electron Microscopy coupled to X-Ray Dispersive Energy Spectrometry (SEM-EDS) was applied to analyze the microelemental composition and the surface mapping of microbial biomass, in the presence and absence of 30 μg mL−1 Cu(II) and Cr(VI) after 72 h of incubation. Additionally, a shotgun proteomic analysis was carried out using nanoUHPLC-ESI-MS/MS on cytosolic proteins and the cell-free supernatants to analyze the differential protein expression at the intracellular and extracellular level in the presence of the metals. Bioinformatic analysis was performed using the Swiss-Prot database specific for S. cerevisiae and MASCOT v2.7.1. The comparative analysis of protein expression of the samples was performed using ProteoIQ v2.8. The microorganism responds by adjusting intracellular and extracellular protein expression, and also by adjusting microelemental composition variation. The results show that cells exposed to Cu(II) obtained the advantage of enduring unfavorable conditions, while cells exposed to Cr(VI) decreased the expression of proteins important for repair and cell function.