Growth regulation in Neurospora crassa effects of nutrients and of temperature

Summary Mycelia of Neurospora crassa growing with quite different rates at a given temperature (30°C) are obtained by changing the composition of the culture medium: for instance a duplication time of 220 min is found when cultures are growing in Vogel's minimal medium supplemented with glycerol and one of 80 min when cultures are growing in Vogel's minimal medium supplemented with sucrose and casein hydrolysate. The kinetics of shifth-down and shift-up transitions of growth between culture conditions supporting different rates of growth are described. Temperatures above 40°C and below 20°C severely restrict growth in Vogel's minimal medium supplemented with sucrose. The Arrhenius plot of the constant of the rate of growth suggests that an inactivation process occurs at low temperatures: the molecular basis for such a process is discussed.Abbreviations used A₄₅₀ absorbance at 450 mm