Plasma Membrane Potential of Candida albicans Measured by Di-4-ANEPPS Fluorescence Depends on Growth Phase and Regulatory Factors

The potential of the plasma membrane (Δψ) regulates the electrochemical potential between the outer and inner sides of cell membranes. The opportunistic fungal pathogen, Candida albicans, regulates the membrane potential in response to environmental conditions, as well as the physiological state of the cell. Here we demonstrate a new method for detection of cell membrane depolarization/permeabilization in C. albicans using the potentiometric zwitterionic dye di-4-ANEPPS. Di-4-ANEPPS measures the changes in the cell Δψ depending on the phases of growth and external factors regulating Δψ, such as potassium or calcium chlorides, amiodarone or DM-11 (inhibitor of H(+)-ATPase). We also demonstrated that di-4-ANEPPS is a good tool for fast measurement of the influence of amphipathic compounds on Δψ.