Bañuelos O, Casqueiro J, Gutiérrez S, Riaño J, Martín J F
Faculty of Biology, University of León, Spain.
Antonie Van Leeuwenhoek. 2000 Jan;77(1):91-100. 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.
研究了铵及其他氮源对产黄青霉肿胀孢子中氨基酸利用的调控作用。铵可抑制接种于完全培养基中的产黄青霉肿胀孢子对L-赖氨酸、L-精氨酸和L-鸟氨酸的利用，但对碳源缺乏培养基中的孢子无此作用。铵离子（35 mM）可完全抑制在碳源和氮源存在下培养的孢子对L-[14C]赖氨酸的转运。然而，在碳源阻遏解除的条件下（无糖生长，以氨基酸作为唯一碳源），L-[14C]赖氨酸的转运仅受到部分抑制。竞争实验表明，1 mM的L-赖氨酸可抑制L-精氨酸的利用，反之，L-精氨酸可抑制L-赖氨酸的摄取。高浓度的L-鸟氨酸（100 mM）可抑制产黄青霉肿胀孢子对L-赖氨酸和L-精氨酸的利用。总之，铵似乎通过抑制碱性氨基酸通过其特定转运系统的转运，而非通过在碳源阻遏解除条件下起作用的一般氨基酸转运系统，来抑制产黄青霉孢子中碱性氨基酸的利用。
