Heavy water inhibition of cell division: an approach to mechanism.

Abstract

ABS>At concentrations higher than about 75%, deuterium oxide blocks cell division in the eggs of the sea urchin Arbacia punctulata and in those of the annelid Chaetopterus pergamentaceus. The block is reversible, although cells that have been kept is a deuterium-rich medium for long periods relative to the time for one mitotic cycle may show multipolar and irregular divisions after removal to normal water, and may subsequently cytolyze. The antimitotic action is manifested at all stages of the mitotic cycle and, to a significant extent, during cytokinesis. An important feature of the mitotic block is that it becomes effective almost immediately after the cells are placed in D2O and is quickly reversed when the cells are washed free of D2O. Whereas D2O blocks mitosis at all stages it does not destroy the achromatic apparatus, nor does it cause wholesale regression of cleavage furrows. Instead, it exerts a powerful stabilizing effect upon these structures. This appears to be related to a sharp and reversible increase in cytoplasmic viscosity evoked by immersion of nondividing cells in D2O. Examination of a number of alternative explanations of the effect leaves as the most useful working hypothesis a rigidification of the mitotic apparatus, possibly throughmore » a small increase in the strength of individual hydrogen bonds which cross-link macromolecules or small particles. For large, multiply cross-linked structures, such changes for individual bonds would produce very large cooperative effects in the direction required by the data.« less