iBB

The role of the cell wall in yeast response and tolerance to stress is frequently neglected. A BSRG-iBB research paper just published in Scientific Reports, provides, for the first time, a comprehensive view of the alterations occurring at the cell wall in a yeast population adapting to sub-lethal stress induced by acetic acid. The results reveal changes to the cell wall polysaccharide composition and nanomechanical properties, as well as alterations in the transcript levels of key cell wall biosynthetic genes. This paper reinforces the notion that the adaptive yeast response to acetic acid involves coordinated alterations of the cell wall at the biophysical and molecular levels. The gathered knowledge is important for the design of superior industrial strains and for the efficient control of the deleterious activity of spoilage yeasts, particularly in the Food Industry. This research work is first-authored by the PhD student of the PhD programme in Biotechnology and Biosciences Ricardo Ribeiro (FCT_DP AEM fellowship), performed under the supervision of Isabel Sá-Correia. This collaborative study with Fábio Fernandes (BSIRG-iBB) and Mário S. Rodrigues and his team (BioISI, Faculty of Sciences, ULisboa), is also coauthored by Cláudia Godinho (posdoc researcher) and the PhD student Nuno Bourbon-Melo (FCT_DP BIOTECnico) from the BSRG-iBB team.

The ability of Saccharomyces cerevisiae to overcome the stress induced by cytotoxic compounds depends on the activity of plasma membrane transporters of the ABC superfamily, presumably through the questionable unspecific efflux of multiple drugs and xenobiotic compounds. A recent paper by iBB researchers provides new insights into the biological role of the ABC transporter of the pleiotropic drug resistance family of putative drug efflux pumps Pdr18, proposed to mediate ergosterol incorporation in plasma membrane. Pdr18 expression was found to help cells to counteract acetic acid-induced decrease of plasma membrane lipid order, increase the non-specific membrane permeability and decrease the transmembrane electrochemical potential. Results support the notion that Pdr18-mediated multistress resistance is linked to the status of plasma membrane lipid environment related with ergosterol content and the associated plasma membrane properties. The paper, published in Scientific Reports, results from the PhD project of Cláudia Godinho, advised by Prof. Isabel Sá-Correia from BSRG-iBB in collaboration with Fábio Fernandes and Sandra Pinto from BSIRG-iBB).