STUDIES ON STREAMING : I. Inhibition of Protoplasmic Streaming and Cytokinesis of Chaos chaos by Adenosine Triphosphate and Reversal by Magnesium and Calcium Ions

In Chaos chaos streaming, motility, and cytokinesis were inhibited nearly 100% for several hours by 2.5–5 mM sodium adenosine triphosphate (ATP)¹ added to culture fluid. All three effects were completely prevented by the addition of equimolar Mg⁺⁺ or Ca⁺⁺ ions but not Na⁺ to the ATP/culture fluid solution. The effects of ATP were not reproduced by EDTA, EGTA, colchicine, or AMP. Sodium pyrophosphate produced about 50% inhibition at 5 mM. Studies with ¹⁴C-ATP showed that 5 x 10^-5 to 5 x 10^-4 mmole of ATP was firmly associated with each milliliter of packed cells after an hour's incubation at 24°C. Labeling studies also showed that prevention of the ATP effects by Mg⁺⁺ ions was not due to a decrease in the amount of ATP associated with the cells.