Circadian rhythmicity during prolonged chemostat cultivation of Neurospora crassa

Following exposure to light and attainment of steady-state in the chemostat, Neurospora was grown in constant conditions of darkness at 25 °C for 6 days. Biomass samples were taken every 4 h for the extraction of RNA and protein, and the state of the circadian clock was assessed by assaying the levels of three rhythmically expressed mRNAs; frequency (frq), antisense frq (qrf) and clock-controlled gene-14 (ccg-14), and by monitoring the clock-controlled rhythm of sporulation. Our results indicate that the Neurospora clock continued to run in the chemostat. This is the longest reported time that Neurospora has been grown in a chemostat in filamentous form and opens up the possibility of studying the response of Neurospora to a range of stimuli in the absence of confounding effects due to; alterations in growth rate, aging, and changing conditions of the growth medium.