Treatment with NEM blocks cytokinesis but does not cause cleavage furrow regression. (A, B) Time-lapse phase-contrast images showing a dividing (A) crane-fly spermatocyte treated with 50 μM NEM [see Additional file 7] or (B) Drosophila spermatocyte treated with 10 μM NEM. In both experiments, cells were treated just after the time-point depicted in the second panel. Note the appearance of blebs after treatment of the Drosophila spermatocyte (arrows) [see Additional file 8]. Bars, 10 μm. (C) Plot of the change in cell diameter (ordinate) over time (abscissa) for the crane-fly (+) and Drosophila (o) spermatocytes shown in A, B. NEM was added at the time-point indicated by the left arrow. In the crane-fly spermatocyte, cleavage remained arrested even after washing with Insect Ringers (right arrow).