Induction of synchronous encystment in a hypotrichous ciliate, Histriculus sp

A method for the induction of synchronous encystment in a hypotrichous ciliate,Histriculus sp. is described. When the ciliates were transferred into 10× Osterhout's solution at around 7 h after disappearance of the food organisms, Tetrahymena, and were maintained at 20 °C, the organisms underwent synchronous encystment. Phase 1 cells (precystic cells) appeared at around 2 h after transfer into the 10× Osterhout solution, and almost all organisms had transformed into phase 1 cells approx. 3 h after transfer. The first cyst appeared at around 3 h after transfer into the 10× solution and essentially 100% of the organisms had transformed into cysts within approx. 4.5 h after transfer.