Figure 6

Cellular viability assay. The cellular viability of wild-type KT2440 (blue) and the streamlined strain EM383 (green) was compared in stationary-phase cultures. Cells grown overnight in LB medium or in M9 minimal medium added with 0.2% (w/v) of either citrate, glucose, or succinate were stained with propidium iodide (PI) and analysed by flow cytometry to estimate the percentage of dead cells (i.e., PI⁺ cells). The results of at least four biological independent experiments are represented as box plot charts (Tukey-style box plots). The median is marked as a grey line within the charts and the dark grey dots outside the box represent the data outliers. The results for P. putida KT2440 grown in M9 minimal medium with citrate and some of the replicas in LB and M9-glucose are taken from Martínez-García et al. [36]. The asterisks (**) indicate a significant difference for strain EM383 as compared to wild-type KT2440 according to the Mann–Whitney U test (P <0.01).