Fig. 4: Activity of the flagellar regulon and motility in natural isolates of E. coli.
a Relation between flagellar regulon activity and motility for representative ECOR strains (indicated here and throughout by their number in the collection) compared to MG1655 WT (IL28) and Ptac (IL29) strains grown in a liquid TB medium; corresponding inducer concentrations (IPTG, µM) used for the Ptac strain are indicated by numbers in red. The same mid-exponential cell culture was used to measure the PfliC reporter activity in the plate reader (GFP fluorescence normalized to OD600) and a population-averaged swimming velocity (see Methods for details). Each point represents the mean value for both parameters measured in three independent cultures of each strain (n = 3), with error bars indicating the standard deviations. b Diameters of spreading zones formed by MG1655 WT, Ptac and ECOR strains in porous 0.27% TB agar, measured after 4–5 h incubation at 34 °C Bar charts represent the mean diameter across three individual colonies of each strain (overlaid as empty black circles) and error bars indicate standard deviations. c Correlation between PfliC reporter activity of in E. coli strains grown in liquid or on the semi-solid medium (0.5% TB agar) (n = 3 biological replicates; mean ± s.d.). d Dependence of the population-averaged swimming velocity on PfliC activity for ECOR, MG1655 WT and Ptac strains grown on semi-solid medium (n = 3 biological replicates, mean ± s.d.). Data for other ECOR strains are shown in Supplementary Fig. 10. Source data are provided as a Source Data file.
