FIG. 4.

Influence of iron availability on twitching motility. P. aeruginosa K1120 was inoculated onto succinate minimal agar with or without Fe supplementation, and following incubation at 37°C for 40 h, the twitching zones were stained (bottom) and their diameters measured (top). Error bars represent the standard errors of the means for a representative assay performed in triplicate. Bars under twitching zones (bottom) represent 10 mm. Similar results were observed using glucose minimal medium.