title: Ligninolytic enzyme system of Phanaerochaete chrysosporium: synthesized in the absence of lignin in response to nitrogen starvation.
abstract: The relationship between growth, nutrient nitrogen assimilation, and the appearance of ligninolytic activity was examined in stationary batch cultures of the wood-destroying hymenomycete Phanerochaete chrysosporium Burds. grown under conditions optimized for lignin metabolism. A reproducible sequence of events followed inoculation: 0 to 24 h, germination, linear growth, and depletion of nutrient nitrogen; 24 to 48 h, cessation of linear growth and derepression of ammonium permease activity (demonstrating nitrogen starvation); 72 to 96 h, appearance of ligninolytic activity (synthetic 14C-lignin leads to 14CO2). Experiments with cycloheximide demonstrated that appearance of ligninolytic activity occurs irrespective of the presence of lignin; lignin did not induce additional activity. Addition of NH4+ to cultures immediately prior to the time of appearance of the ligninolytic system delayed its appearance, suggesting that the NH4+ led to interference with synthesis of the enzyme system. Addition of NH4+ to ligninolytic cultures resulted in an eventual, temporary decrease in ligninolytic activity. The results suggest that all or essential protein components of the ligninolytic enzyme system are synthesized as part of a series of physiological ("secondary metabolic") events that are initiated by nutrient nitrogen starvation.
mesh_terms: D001487:Basidiomycota / Q000201:enzymology* / Q000254:growth & development; D004790:Enzyme Induction; D008031:Lignin / Q000378:metabolism* / Q000494:pharmacology; D009584:Nitrogen / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D013997:Time Factors
chemical_list: D000644:Quaternary Ammonium Compounds; D008031:Lignin; D009584:Nitrogen