Single-Cell Biophysics: Measurement, Modulation, and Modeling

Single-Cell Biophysics: Measurement, Modulation, and Modeling

Poster Abstracts

46-POS Board 23 Surface Properties of Saccharomyces Cerevisiae during Fermentative and Respiratory Cycles Lucia Lavaisse 1,2 , Axel Hollmann 1,3 , Monica Nazareno 2 , Anibal Disalvo 1 . 1 Laboratory of Biointerphases and Biomimetic Systems, CITSE UNSE CONICET, Santiago del Estero, Santiago del Estero, Argentina, 2 Laboratory of Antioxidants and Oxidative Process CITSE UNSE CONICET, Santiago del Estero, Santiago del Estero, Argentina, 3 National University of Quilmes, Bernal, Buenos Aires, Argentina. The aim of this work is evaluate the zeta potential (ZP) evolution during the growth of Saccharomyces cerevisiae under different stresses to understand the physiological states in connection to changes in cell surface properties. Yeast growth was evaluated following the electrophoretic mobility of cells in an electric field, together with CFU, OD 600nm , pH and size variations. S.cerevisiae spp cultures show different ZP mean values along the growth phases. A single cell method permits to identify different subpopulations with defined ZP values coexisting at each growth stage, indicating that cells in different states of growth are present at each of them. Accordingly, cells can be classified into subpopulations considering their surface charge that anticipates growth phase changes. In the fermentative cycle, the release of acid to media produces a decrease in the negative surfaces charges. In contrast, in the respiratory cycle, the zeta potential decreases abruptly at constant pH as a consequence of changes in the chemical composition of the cell wall or a cell volume change. ZP measurements were applied on cells exposed at different stresses and showed that cells in exponential phase were more sensitive to stresses. These data can be correlated with size information obtained by DLS. It is concluded that the ZP is a useful technique for monitoring cell culture, and to sense changes in the physiological state of the cell.

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