Intracellular calcium fluctuations in relation to cell division in synchronized Tetrahymena pyriformis

This research was designed to investigate the levels of cytoplasmic calcium in normal synchronously dividing cultures of Tetrahymena and in cultures treated with 5 µM A23187, a calcium ionophore. The specific goal was to correlate any fluctuation in cytoplasmic calcium to cell division and the morphogenetic development of the cells.

Tetrahymena pyriformis was the organism of choice for this investigation because of its rapid growth rate, ease of synchronization, and an orderly process of oral development preceding cell division. The techniques employed on synchronized cells included atomic absorption spectroscopy and a novel application of the calcium sensitive photoprotein aequorin to a cell free solution as well as morphological studies by silver and lead impregnation stain techniques.

The results of these experiments illustrated that in both control synchronized cultures and cultures treated with 5 uM A23l87 there is a fluctuation in cytoplasmic calcium which correlates to the reactivation of oral morphogenesis. Also, calcium-45 studies indicated that A23l87 causes the release of intracellularly stored calcium. These data are in close agreement with the known fluctuations of cyclic nucleotides in Tetrahymena, and the current concepts of the interrelationship of calcium and cyclic nucleotide metabolism.