Polymyxin sensitivity of P. luminescens. TT01gfp and mutant strains were grown overnight in LB broth and inoculated into fresh LB without (black curve) or with (grey curves) 2.5 μg ml-1 polymyxin B (PB) added. The cells were grown for 24 h at 30°C and OD600 readings were taken every 15 mins. The growth curves of all of the strains were identical in the absence of added PB and therefore only a single representative curve (of TT01gfp) is shown. The growth curves of the strains growing in the presence of PB are labeled appropriately. Although the experiment was repeated 3 times only a representative growth curve of each mutant is presented.