Suppression of Cytoplasmic Division in Amoeba proteus

Abstract

CYTOPLASMIC division in Amoeba proteus can be suppressed by the application of strong light during the division process¹. The same can be achieved as follows. Division is allowed to proceed undisturbed until nuclear division is complete. When the cell becomes elongated and the division furrow appears, slight pressure with a glass needle is applied for short intervals alternately on each one of them, thus shifting parts of the liquid endoplasm back and forth from one prospective daughter cell into the other. After about 7–10 min. of such treatment, without having completed the cleavage the cell resumed its normal interphase appearance. The surface, which had been covered with blebs, becomes smooth, pseudopodia are formed, and the cleavage furrow gradually disappears. Pressure applied for the same length of time before the completion of nuclear division does not prevent either nuclear or cytoplasmic division. Once the furrowing process is suppressed no cytoplasmic division occurs before the next full cell division about 20–28 hr. later.