RADIOACTIVE PHOSPHORUS ACCUMULATION AND DISTRIBUTION IN TETRAHYMENA

¹ University of Arisona, Tucson, Arizona

1. Tetrahymena in distilled water containing P³² concentrated the isotope to an extent of 450 times that contained in comparable volumes of water after nine hours.

2. The accumulation of P³² by individual Tetrahymena varied with population density. With large populations, the amount of phosphate accumulated per cell was sharply reduced, whereas with low population densities larger quantities were accumulated. More than ten times as much P³² was found in mating type II than in mating type I.

3. The induction of conjugation was found to be strongly influenced by the amount of cellular debris present. The greatest amount of conjugation was obtained by the use of large population densities with gentle centrifugation. It was suspected also that age as influencing cell fragility was important here.

4. Mating type II showed a significantly increased rate of P³² accumulation six hours after addition of this isotope in distilled water, while mating type I was found to concentrate P³² at a slow constant rate.

5. Three times as much phosphate was accumulated during nine hours in the presence of glucose as when in distilled water alone with either mating type.

6. Although a biphasic accumulation was noted with low population densities prepared for the induction of conjugation, this was probably primarily because of an increased uptake by mating type II. Similar information was not obtained with large population densities, possibly because of the numbers effect.

7. Nearly five times as much phospholipid phosphorus was found in mating type II as compared to mating type I. This appears to be correlated with the greater ion accumulation ability found in type II. Only about twice as much acidsoluble phosphorus was found in type II compared with type I, however.