INHIBITION OF CYTOKINESIS AND FORMATION OF GIANT-CELLS IN POTERIOOCHROMONAS-MALHAMENSIS BY ORGANIC LEAD COMPOUNDS AND OTHER AGENTS

Organic lead compounds inhibit cytokinesis of the chrysophycean flagellate Poterioochromonas malhamensis leading to giant, multinucleate cells. This action on cytokinesis is compared with the long-time effects of various compounds with better known subcellular activities. Calcium (10 mM), and cytochalasin B (up to 100 μg/ml) do not visibly influence cytokinesis. Caffeine (1 mM) totally inhibits multiplication of the algae whereas calcium has only a slight and cytochalasin has no effect on this parameter. The other reference-compounds (colchicine, sodium cacodylate, deuterium oxide, local anesthetics, and sodium dodecylsulfate) all inhibit cell multiplication, simultaneously leading to giant multinucleate cells, obviously by inhibition of cytokinesis. The most potent inhibitor of cytokinesis is triethyl lead which was shown to be 250× more effective than colchicine in respect to the molar concentrations. The comparison of the effects of tetraethyl lead and triethyl lead with the reference agents leads to the conclusion that organic lead compounds might inhibit cytokinesis of Poterioochromonas malhamensis by disintegrating peripheral microtubules and/or by interfering with structures and functions of membranes. © 1979 Springer-Verlag.