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Effect of Amino Acids on Coremium Development in Penicillium claviforme
Abstract
Amino acids added to the growth medium stimulated development of coremium primordia in mycelium of Penicillium claviforme. Casein hydrolysate, l-asparagine, l-serine, l-glutamine, l-proline, l-hydroxyproline, l-glutamate and glycine accelerated development and also increased the final number of primordia per unit area of mycelium. A nearly linear relationship existed between the logarithm of casein hydrolysate concentration and the numbers of primordia developed, and a similar relationship was also shown with glutamate as nitrogen source. Mycelium developing from spores sown on agar plates showed some sites for coremium development within a few hours of germination, although most sites were not established until about 24 h later when the germlings had fused to form a network. At least 27 h exposure was required for amino acids to stimulate primordium development in 24 h-old mycelium. Cycloheximide, glucosamine and nystatin promoted primordium development at concentrations inhibiting hyphal growth; 2-deoxyglucose inhibited primordium formation. It was concluded that possible sites for coremia develop into primordia as a result of changes in nitrogen metabolism, and that local variations in the concentrations of certain amino acids or their metabolites may decide the pattern in which primordia form in the colony.
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© Society for General Microbiology, 1977