An eternal clock? - monitoring the Neurospora crassa circadian clock in chemostat culture

Neurospora crassa is a filamentous fungus and a model organism for the study of the molecular basis of circadian clocks. Rhythmic sporulation of this organism is maintained for prolonged periods in the dark with a periodicity of approximately 22 h. Three genes; frequency, white collar-1 and white collar-2, and their associated kinases and phosphatases, are key components of the circadian clock that drives this switch between vegetative hyphal growth and asexual development. To date regulation of these genes and the interactions of their RNA and protein products has been investigated using tissue from batch cultures of Neurospora. The use of batch cultures sets a time limit on observations of the molecular clockwork and culture conditions change throughout the experiment as the organism utilizes the carbon source and excretes by-products of metabolism. Here we report conditions for chemostat cultures of Neurospora, that overcome the afore mentioned problems associated with batch cultures.