Furfural causes vacuoles to go from large single organelles to several smaller ones. Exponentially growing yeast cells were either untreated or treated with 25 mM or 50 mM furfural. Aliquots of cells were removed and stained with the vacuole targeted dye FM 4-64. Representative images of yeast with no inhibitor (left column; single large vacuoles), exposed to 25 mM furfural (middle column; two to four medium-sized vacuoles) and 50 mM furfural (right column; small and fragmented) are shown. Images of cells were taken 6 h after furfural treatment.