Effect of carbon source and pH of the growth medium on spore germination inPhycomyces blakesleeanus
- 42 Downloads
Phycomyces blakesleeanus sporangiospores responded differently to activation by physical and chemical stimuli. Spores that were physically (heat shock) activated or chemically (ammonium acetate) activated germinated and grew at pH 4.5 with the hexoses glucose, fructose, galactose, andN-acetylglucosamine, and with glycerol and amino acids. Under these conditions, physically activated spores showed a lower, although significant growth with the hexoses fructose, galactose,N-acetylglucosamine and with glycerol. On the other hand, physically activated spores incubated at alkaline pH (pH 7.3) required glucose to germinate; a requirement not observed with chemically activated spores, which showed significant growth in the other hexoses tested. Both physically and chemically activated spores incubated at pH 7.3 were unable to germinate and grow with amino acids and glycerol. These results suggest that there are different targets for activation of the spores by physical and chemical treatments. The levels of the fermentative enzymes alcohol dehydrogenase and lactate dehydrogenase and of the oxidative enzyme NAD+-isocitrate dehydrogenase were higher in cells grown at pH 4.5 in medium containing glucose; however, alcohol dehydrogenase and lactate dehydrogenase appear not to be affected by a change in the pH of the growth medium.
Key wordsSpore activation Phycomyces Carbon source pH
Unable to display preview. Download preview PDF.
- Dominguez-Gutierrez LG, Martínez-Cadena MG (1989) Invertase secretion byPhycomyces blakesleeanus: regulation by the carbon catabolite repression and by the pH of the growth medium. J Gen Microbiol 135: 2807–2812Google Scholar
- Hartz TK, Houston MR, Lockwood LB (1978) Substrate specificity and kinetic properties of NADP+-dependent alcohol dehydrogenase ofPhycomyces blakesleeanus. Mycologia 70: 586–593Google Scholar
- Hildenberg W, Burke PV, Sandmann GS (1987) Metabolic pathways. In: Cerdá-Olmedo E, Lipson ED (eds)Phycomyces. Cold Spring Harbor Laboratory, Cold Spring Harbor, pp 155–198Google Scholar
- Schwitzguebel JP, Moller IM, Palmer JM (1981) Changes in density of mitochondria and glyoxysomes fromNeurospora crassa: a re-evaluation utilizing silica gel gradient centrifugation. J Gen Microbiol 126: 289–295Google Scholar
- Van Laere AJ (1983) Stimulation of phosphofructokinase fromPhycomyces blakesleeanus and some other fungi by micromolar concentrations of fructose-2,6-bisphosphate. J Gen Microbiol 129: 3281–3285Google Scholar
- Van Laere AJ, Carlier AR (1977) Decarboxylation of gluconic and fructose by dormant and activated spores ofPhycomyces blakesleeanus Burgeff. Biochem Physiol Pflanz 171: 151–156Google Scholar
- Van Laere AJ, Van Assche JA, Furch B (1987) The sporangiospore: dormancy and germination. In: Cerdá-Olmedo E, Lipson ED (eds)Phycomyces. Cold Spring Harbor Laboratory, Cold Spring Harbor, pp 247–279Google Scholar