Control of Ciliary Activities by Adenosinetriphosphate and Divalent Cations in Triton-Extracted Models of Paramecium Caudatum

Abstract

1. Cilia of Paramecium candatum extracted with Triton X-100 were reactivated in the presence of ATP and Mg²⁺. 2. The beating frequency of the reactivated cilia is a function of both the ATP and Mg²⁺ concentrations. 3. The reactivated cell models swam forward when the Ca²⁺ concentrations in the ATP-Mg²⁺ medium was kept below 10^-7M. They swam backward when the Ca²⁺ concentration was above 10^-6M. This was due to a reversed orientation of the effective power stroke of the reactivated cilia. 4. In the absence of Mg²⁺ the cilia failed to beat, even though ATP was present. If Ca²⁺ was then added the cilia assumed a new orientation, pointing toward the anterior without beating. 5. Ni²⁺ inhibited ciliary beating in the reactivated models, but has no influence on changes in the orientation of the cilia produced by ATP and Ca²⁺. This suggests that one ATP-activated system is responsible for beating, while another governs the direction of the effective stroke. 6. Mn²⁺ is half as effective as Mg²⁺ for inducing ciliary beating in the extracted models in the presence of ATP. 7. Salyrgan strongly inhibits Mg²⁺-ATP activated ciliary activity of the model. 8. Bioelectric control of ciliary activity by the cell membrane of live animals is discussed.