Fig 2. Chemicals that antagonise the effects of arginine de-repress AMT1.1 expression in the presence of ammonium and nitrate.

AMT1.1 transcript levels were measured in wild type cells exposed to different nitrogen contexts (8 mM NH₄⁺, 4 mM NO₃^-, or no nitrogen), and in the presence / absence of 1mM canavanine and 1mM L-NAME. Samples were collected after 1 hour in the different conditions. Error bars represent the standard deviation of at least three replicates from independent PCR runs. Cells were first left to grow for several days in medium containing 8 mM NH₄⁺ until they reached the exponential growth phase. Cells were then washed and transferred to nitrogen-free medium where they were exposed to different nitrogen sources and chemicals as indicated on the figure.