Fig. 4. Regulation of DIF-1 synthetic capacity by cAMP and DIF-1. Cells of strain Ax2 were starved in shaken suspension at 2x107/ml in KK2 buffer and after the first hour, pulsed with 50 nM cAMP every 6 minutes for a further 6 hours. These cells were subdivided, 4 mM cAMP and 100 nM DIF-1 added as indicated, and samples taken for northern analysis and enzyme assays. A second experiment gave a similar result.