Protocol

Maintaining Clonal Paramecium tetraurelia Cell Lines of Controlled Age through Daily Reisolation

¹ Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique, FRE3144, F-91198 Gif-sur-Yvette, France
² Laboratoire de Biologie Cellulaire 4, Centre National de la Recherche Scientifique, UMR 8080, Université Paris-Sud, 91405 Orsay Cedex, France
³ Laboratoire de Génétique Moléculaire, Centre National de la Recherche Scientifique, UMR 8541, École Normale Supérieure, F-75230 Paris, France
⁴ Laboratoire de Biométrie et Biologie Évolutive, Centre National de la Recherche Scientifique, UMR 5558, Université Lyon 1, F-69622, Villeurbanne, France
⁵ Laboratory of Molecular Biology and Department of Genetics, University of Wisconsin-Madison, WI 53706, USA
⁶ Department of Biology, Indiana University, Bloomington, IN 47405-3700, USA

⁷Corresponding author (emeyer{at}biologie.ens.fr).

INTRODUCTION

The sexual cycle of Paramecium tetraurelia can be managed by controlling food uptake, allowing the study of developmentally regulated differentiation in synchronous cultures. Clonal cell lines can be established easily by single cell isolation and can be grown in bacterized grass infusion medium for a large number of vegetative divisions before entering senescence. Sexual reproduction is triggered by starvation and therefore can be induced or prevented as needed by controlling the availability of food. Given a constant supply of food, P. tetraurelia cells will remain in the vegetative phase of their life cycle and, at 27°C, will divide by binary fission every 6 h. The daily reisolation procedure described here results in populations of P. tetraurelia of known age and produced under reproducible physiological conditions, which can help to standardize experiments. Paramecia produced under these conditions are suitable for immunocytochemical studies or use in genetic cross experiments.