Strains bearing plasmids expressing YFP under the control of native or synthetic promoters were grown overnight in synthetic drop-out medium minus leucine (SD-leu; Sigma) containing 1.1 g/l monosodium glutamate as a nitrogen source, and 200 mg/l G418. Cells were diluted 20-fold in duplicate in minimal Delft medium (13 (link)) with the necessary supplements at pH 6 containing 250 mg/l G418 and grown for 4h to re-enter the log phase. Following this, one replicate was diluted to an OD of approximately 0.1–0.2 in Delft medium, pH 6, while the other was washed and diluted two-fold in Delft medium, pH 2.5. The latter, lower dilution was necessary to have enough cells for fluorescence measurements. In the case of inductions by oxidative stress, cells were diluted two-fold in Delft medium, pH 6, and the oxidative agent diamide (Sigma-Aldrich) was added to a final concentration of 2 mM from a concentrated stock of 500 mM. For inductions by osmotic stress, cells were washed and diluted 2-fold in Delft, pH 6 containing 1 M sorbitol. YFP fluorescence was then measured at 4 or 24 h by flow cytometry, using the base strain without YFP for background correction.