Furfural causes nuclear chromatin to go from tight organized spheres to diffuse unorganized structures. 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 DNA specific dye DAPI, which is shown as lightly stained structures in the cytoplasm. (A) Representative images observed with no inhibitor (left column; tightly compacted spheres), 25 mM furfural (middle column; diffuse chromatin) or 50 mM furfural (right column; diffuse chromatin) are shown. Stained chromatin appear as white structures. Images of cells were taken 6 h after furfural treatment. (B) Percent of cells at each concentration of furfural that contain diffuse chromatin similar to right two images in (A) at 0 h, 6 h and 24 h. Data represent an average of three experiments with standard error indicated. At each time point 100 or more cells were examined.