Transformation of Trophic Hartmannella Culbertsoni into Viable Cysts by Cyclic 3',5'-adenosine Monophosphate

Hartmannella culbertsoni, a free-living soil ameba, undergoes differentiation to be transformed into a double-walled cyst when exposed to a nonnutrient medium containing magnesium ions and taurine (Raizada and Krishna Murti, 1971) . The transformation of the trophic form to mature cysts is usually preceded by a stage during induction when the ameba assumes a round and well-defined shape after the withdrawal of the pseudopodia. Evidence is adduced in this communication to show that cyclic 3', 5'-adenosine monophosphate (CAMP) can replace magnesium ions and taurine in the nonnutrient agar medium and that CAMP brings about a comparable degree of encystation of the ameba. The presence of magnesium ions and taurine has also been shown to result in a threeto fourfold increase in the rate of synthesis of CAMP by the ameba .