Oscillations in Yeast Observed Electrically

Abstract

It has previously been demonstrated that oscillations occur in actively growing yeast cultures. These oscillations occur because yeast cells synchronize their glycolytic pathway following a saturation period. Periodic changes in the levels of intermediate metabolites in glycolysis as well as changes in pH ofthe media have been measured, that demonstrate this phenomenon. Here we observe that the conductivity of the media also changes periodically when yeast cells are cultured under similar conditions. As conductivity is easily measured, this provides a simple, more quantitative method to study these changes than those currently used. An electrical biosensor referred to as ECIS (electrical cell surface impedance sensing) was used to study the small conductivity changes (in the order of 0.1%). No significant differences in the observed periods were found in the two yeast strains or the commercially purchased yeast extract studied.