Differential interference contrast (DIC) light micrograph of cytokinesis (cellular division) in a cell that has had the enzyme topoisomerase II inhibited. Topoisomerase II plays a role in the condensation of chromosomes (dark purple) prior to mitosis (nuclear division), the formation of two daughter nuclei from one parent nucleus. Inhibition of topoisomerase II prevents complete condensation of the chromosomes. Here this has lead to the incomplete segregation of the chromosomes, which are still attached as the cell is dividing. Giemsa stain.