Multiple resistance factors collectively promote inoculum-dependent dynamic survival during antimicrobial peptide exposure in Enterobacter cloacae
Fig 5
OmpT contributes to cecB resistance via proteolytic cleavage of cecB.
Overnight cultures were diluted (A) 10-fold or (B) 100-fold into fresh LB containing 20 μg/mL cecB, and cells were grown at 37°C for 24 hours. Where applicable, expression of ompT from pBAD was induced with 0.1% arabinose. OD600 measurements were taken every 5 minutes. Error bars represent standard deviation (n = 3). (C) Mid-exponential cells were placed on 0.8% agarose pads containing the indicated amounts of cecropin and incubated at 37°C. Representative, cropped frames from a timelapse movie are shown. Red arrow indicates a cell which initially divided, but later succumbed to cecropin and lysed. (D) Effects of OmpT active site mutations were tested using conditions in (A).