specific transport system for lysine is fully inhibited by ammonium in Penicillium chrysogenum: An ammonium-insensitive system allows uptake in carbon-starved cells

• Published in: Antonie van Leeuwenhoek Vol. 77; no. 1; pp. 91 - 100
• Main Authors: Bañuelos, Oscar, Casqueiro, Javier, Gutiérrez, Santiago, Riaño, Jorge, Martín, Juan F
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 2000; Springer; Springer Nature B.V
• Subjects: Amino acids; Amino Acids - metabolism; ammonium; ammonium compounds; arginine; Bacteria; Biological and medical sciences; Biological Transport; carbon; Carbon - metabolism; Culture Media; Fundamental and applied biological sciences. Psychology; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; lysine; Lysine - metabolism; Microbiology; Mutation; Mycology; nitrogen; Penicillium chrysogenum; Penicillium chrysogenum - genetics; Penicillium chrysogenum - metabolism; Penicillium chrysogenum - physiology; Quaternary Ammonium Compounds - metabolism; spores; Spores, Fungal - metabolism; Spores, Fungal - physiology; sugars; Ammonium; Transportation system; Basic aminoacid; Environmental factor; Metabolism; Uptake; Penicillium chrysogenum; Fungi; Regulation(control); Arginine; Lysine; Membrane transport; Fungi Imperfecti; Ornithine; Thallophyta
• ISSN: 0003-6072; 1572-9699
• DOI: 10.1023/A:1002427916923

The regulation exerted by ammonium and other nitrogen sources on amino acid utilization was studied in swollen spores of Penicillium chrysogenum. Ammonium prevented the L-lysine, L-arginine and L-ornithine utilization by P. chrysogenum swollen spores seeded in complete media, but not in carbon-deficient media. Transport of L-[¹⁴C]lysine into spores incubated in presence of carbon and nitrogen sources was fully inhibited by ammonium ions (35 mM). However, in carbon-derepressed conditions (growth in absence of sugars, with amino acids as the sole carbon source) L-[¹⁴C]lysine transport was only partially inhibited. Competition experiments showed that L-lysine (1 mM) inhibits the utilization of L-arginine, and vice versa, L-arginine inhibits the L-lysine uptake. High concentrations of L-ornithine (100 mM) prevented the L-lysine and L-arginine utilization in P. chrysogenum swollen spores. In summary, ammonium seems to prevent the utilization of basic amino acids in P. chrysogenum spores by inhibiting the transport of these amino acids through their specific transport system(s), but not through the general amino acid transport system that is operative under carbon-derepression conditions.