20240903 Hamm & Gray ppk relA spoT supplementation growth curves

Effect of media supplements on growth of ppk relA spoT mutants. Escherichia coli strains MG1655, MJG0224 (MG1655 ∆ppk-749), MJG1287 (MG1655 ∆relA782 ∆spoT1000::kan+), and MJG1282 (MG1655 ∆ppk-749 ∆relA782 ∆spoT1000::kan+) were grown overnight at 37C with shaking in Lysogeny Broth (LB), then normalized to A600 = 1 and rinsed three times with sterile PBS. The resulting cell suspensions were diluted 1:40 into LB or M9 minimal medium containing 0.4% glucose and 100 µM FeCl3 with or without supplementation with 0.1% or 1% (w/v) of yeast synthetic dropout mix supplement (Sigma Aldrich cat. #Y1501), casamino acids (Fisher Scientific cat. #BP1424), tryptone (Fisher Scientific cat. #BP1421), or yeast extract (Becton Dickinson cat. #288620). Growth curves were performed in clear 96-well plates in a Tecan Spark plate reader, incubating at 37C with shaking and measuring A600 at 30-minute intervals for 24 hours (n=3-6 experimental replicates, with 3-12 technical replicates per experiment).