pH oscillations and constant low pH delay the appearance of highly branched (colonial) mutants in chemostat cultures of the quorn® myco-protein fungus, Fusarium graminearum A3/5

Circadian rhythmicity during prolonged chemostat cultivation of Neurospora crassa

“…These studies have used bacteria or budding yeast which are considerably easier to culture continuously than Wlamentous fungi that may switch growth forms depending on the culture conditions, forming pellets or clumps of tissue that result in a non homogenous culture. Although chemostat cultures of a number of Wlamentous fungi have been reported including Penicillium chrysogenum (Withers et al, 1995), Fusarium venenatum (Wiebe et al, 1992(Wiebe et al, , 1996, Trichoderma reesei (Pakula et al, 2005), Aspergillus niger (Mainwaring et al, 1999;Swift et al, 1998Swift et al, , 2000, Aspergillus nidulans (Rowley and Pirt, 1972;Sims et al, 2005) and Aspergillus oryzae (Withers et al, 1994), this is the Wrst report of conditions for successful growth of N. crassa in chemostat culture. Our results indicate that under these conditions the circadian clock runs for a period of at least six days in the dark after setting the clock through exposure to light.…”

Peptone changes the timing and accumulation of morphological mutants of the Quorn® myco-protein fungus Fusarium graminearum A3/5 in glucose-limited chemostat cultures

“…They have not been observed in slow dilution rate (D = 0.05 h 3I ) glucose-limited chemostats and their appearance has been delayed by altering the culture pH or by imposing oscillations in the culture pH [7]. However, whenever colonial mutants have been observed in F. graminearum A3/5 cultures they inevitably displace the relatively sparsely-branched population [4,7]. The colonial morphology of these mutants is apparently part of a pleiotropic response to the mutation, which a¡ects various enzymes (generally unknown) and metabolic pathways [6].…”

“…Colonial mutants have been isolated from turbidostat cultures [3,5] and from glucose-, magnesium-and nitrogen-limited chemostat cultures grown at high dilution rates (D = 0.14^0.19 h 3I ) [4,6]. They have not been observed in slow dilution rate (D = 0.05 h 3I ) glucose-limited chemostats and their appearance has been delayed by altering the culture pH or by imposing oscillations in the culture pH [7]. However, whenever colonial mutants have been observed in F. graminearum A3/5 cultures they inevitably displace the relatively sparsely-branched population [4,7].…”

Peptone changes the timing and accumulation of morphological mutants of the Quorn�myco-protein fungusFusarium graminearumA3/5 in glucose-limited chemostat cultures

“…Colonial mutants have been isolated from turbidostat cultures [3, 5] and from glucose‐, magnesium‐ and nitrogen‐limited chemostat cultures grown at high dilution rates ( D = 0.14–0.19 h −1 ) [4, 6]. They have not been observed in slow dilution rate ( D = 0.05 h −1 ) glucose‐limited chemostats and their appearance has been delayed by altering the culture pH or by imposing oscillations in the culture pH [7]. However, whenever colonial mutants have been observed in F. graminearum A3/5 cultures they inevitably displace the relatively sparsely‐branched population [4, 7].…”

“…They have not been observed in slow dilution rate ( D = 0.05 h −1 ) glucose‐limited chemostats and their appearance has been delayed by altering the culture pH or by imposing oscillations in the culture pH [7]. However, whenever colonial mutants have been observed in F. graminearum A3/5 cultures they inevitably displace the relatively sparsely‐branched population [4, 7]. The colonial morphology of these mutants is apparently part of a pleiotropic response to the mutation, which affects various enzymes (generally unknown) and metabolic pathways [6].…”