Growth of E. coli wild type in M9 minimal medium supplemented with FeSO4. (B) Enzyme activity of malate dehydrogenase (MDH), aconitase (ACN), fumarase (FUM), and succinate dehydrogenase (SDH) after μAPPJ treatment. E. coli wild type grown in M9 medium without any iron supplementation was untreated (gray, set to 1.0), exposed to helium/oxygen gas flow (blue), or treated with plasma for 1 min (orange). Residual enzyme activity was determined either directly after treatment (t0, dark bars) or after incubation at 37°C for 20 min (t20, light bars). Averages and standard deviations represent three independent biological replicates.