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Single-Cell Biophysics: Measurement, Modulation, and Modeling
Poster Abstracts
121
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.