Quantification of the Bacillus anthracis siderophores petrobactin and bacillibactin obtained from the IDM cultures of the strains Sterne 34F2 and ΔsodA1 with the addition of different concentrations of paraquat.

aConcentration of siderophores petrobactin and bacillibactin is expressed as µg/ml of supernatant from IDM cultures of B. anthracis.bQuantification was performed three times from the independent extraction and values represent means ± standard deviations.cNO, not observed.*Paraquat (PQ) concentration and incubation times before cell lysate and supernatant harvesting for siderophore quantification are as follows: For exponentially growing cells, 800 µM paraquat was added at OD600 0.4–0.5 and cells were harvested after 1 hour.**Note that of all the samples, the growth of ΔsodA1 is slowed by the addition of paraquat, and so the final OD600 of this sample was slightly lower than that of all others.