title: Polyamine and ornithine metabolism during the germination of conidia of Aspergillus nidulans.
abstract: 1. The activities of ornithine decarboxylase, S-adenosylmethionine decarboxylase and ornithine-2-oxoglutarate aminotransferase were studied during the first 24 h of conidial germination in Aspergillus nidulans. 2. Increases (over 100-fold) in the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase occurred during the emergence of the germ-tube and before the doubling of DNA and this was followed by a sharp fall in the activities of both enzymes by 16h. 3. The increase in ornithine decarboxylase could be largely suppressed if 0.6 mM-putrescine was added to the growth medium. 4. Low concentrations of cycloheximide, which delayed germination by 2h, caused a corresponding delay in the changes in ornithine decarboxylase activity. 5. Ornithine-2-oxoglutarate aminotransferase activity increased steadily during the first 24h of germination. 6. Ornithine or arginine in the growth medium induced higher activity of ornithine-2-oxoglutarate aminotransferase, but did not affect ornithine decarboxylase activity. 7. The significance of these enzyme changes during germination is discussed.
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000037:antagonists & inhibitors / Q000378:metabolism; D001233:Aspergillus nidulans / Q000201:enzymology / Q000254:growth & development*; D003513:Cycloheximide / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D009952:Ornithine / Q000378:metabolism*; D009955:Ornithine Decarboxylase / Q000378:metabolism; D065108:Ornithine Decarboxylase Inhibitors; D009953:Ornithine-Oxo-Acid Transaminase / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D011700:Putrescine / Q000494:pharmacology; D013172:Spores, Fungal / Q000201:enzymology / Q000254:growth & development; D013997:Time Factors
chemical_list: D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D004247:DNA; D003513:Cycloheximide; D009952:Ornithine; D009953:Ornithine-Oxo-Acid Transaminase; D009955:Ornithine Decarboxylase; D012437:Adenosylmethionine Decarboxylase; D011700:Putrescine