Species name： Paramecium caudatum
Faculty of Science, Yamaguchi University Yoshiaki Iwadate
It is not well known that Paramecium cells discharge missiles named "trichocyst" when they are attacked by a predator. Trichocyst discharge and ciliary reversal in Paramecium cells are regulated by the intracellular calcium concentration. We injected caged Calcium into P. caudatum cells and applied ultraviolet (UV) light to the cell for 125ms. This did not induce trichocyst discharge but did induce ciliary reversal . A re-application of UV for 125 ms triggered trichocyst discharge. The threshold of intracellular calcium for trichocyst discharge is higher than those for ciliary reversal.
Iwadate et al., Protoplasma 206, 11-19, 1999
Iwadate and Nakaoka, Cell Calcium 44, 169-179, 2008
(2013.09.03)