On the uptake of nystatin by Saccharomyces cerevisiae 3. Electrochemistry of the yeast cell surface.

The electrophoretic behaviour of fresh and liquid nitrogen stored inocula of Saccharomyces cerevisiae has been studied as a function of pH, ionic strength, buffer composition, growth temperature of the inoculum, number of washings of the inoculum prior to electrophoretic investigation, growth medium used in the preparation of the inoculum, interaction of the inoculum with nystatin, and interaction of the inoculum with calcium ions. The results provide a basis for a discussion of the role of the yeast cell surface in the mode of action of nystatin (a polyene antibiotic), on interaction with sensitive Saccharomyces cerevisiae cells. They indicate the profound importance of the cell surface in the interaction with the antibiotic. Moreover, the results of the temperature growth/electrophoresis experiments support the view that a sharp change in membrane fluidity occurs in the yeast membrane. The results are also discussed in the light of those reported in previous papers on the interaction of yeast cells with nystatin.