New Methods for Cultivating, Harvesting, and Purifying Mass Cultures of the Hypotrich Ciliate Euplotes aediculatus1

A new method is described for mass cultivation of Euplotes aediculatus , a hypotrich ciliate containing omikron ‐symbionts. The ciliate cultures, continuously aerated in Erlenmeyer flasks (5000 ml) with 4500 ml medium, yield densities of 2300 cells/ml which are four to five times higher than cell densities of cultures grown in unaerated Fernbach flasks. Harvesting such cultures involves the application of 25‐μm mesh sieves. Cells so concentrated can be purified by using columns or special chambers in which Euplotes migrates towards the cathodes in an electric field (field strength 7 V/cm).