DIGITONIN-SENSITIVE POOL OF CALCIUM AND T HE CHANGE OF ITS VALUE DURING THE DIVISION CYCLE IN SYNCHRONIZED CULTURE OF TETRAHYMENA-PYRIFORMIS

A very significant intracellular pool of calcium, sensitive to digiton in action and different from one of free cytozolic Ca2+, has been show n to exist in the cells of ciliate protozoan T.pyriformis. Calcium con tent in digitonin-sensitive pool N-dig(Ca2+) has been estimated throug hout the cell cycle in synchronized culture of T.pyriformis. The value of N-dig(Ca2+) decreased in the period of time prior to and at the ce ll division, whereas after the division itself it increased. The possi ble role of the calcium content changes of digitonin-sensitive pool in regulation of cytozolic Ca2+ level and in control of cell division is discussed.