CELL DIVISION - A SECOND CIRCADIAN CLOCK SYSTEM IN PARAMECIUM MULTIMICRONUCLEATUM

Light-dark cycles entrain a pattern of division in a population of individually isolated cells cultured in excess nutrients at 14°C. This pattern persists for at least 8 days in continuous dim light. Both clones which do and which do not express a circadian rhythm of mating-type reversals can be entrained. The phase is a clonal characteristic.