2.70

1. 21% O2 O2 : Media: LB + 0.4% NO3- OD600 : 0.04 0.2 0.92 1.83 2.06 2.70 2.92 3.3 3.61 Time (hr) : 0 1 2 3 4 5 6 7 8 75 50 37 Elastase 25 15 10 ΔlasB mutant PAO1 Fig. S1. Aerobic growth of a ΔlasB mutantand SDS-PAGE analysis of its culture supernatants. The mutant bacteria grown overnight in LB at 37 °C were inoculated at 1:100 in LB + 0.4 % NO3-, and growth was monitored by measuring OD600. Aliquots of the culture were harvested every hour and protein contents present in each culture supernatant (CS) were analyzed by SDS-PAGE. For a comparison, SDS- PAGE of the PAO1 CS harvested after 8 hr aerobic growth was shown to the right. The protein band that corresponds to the mature elastase is shown with an arrow.

2. A Pneu 1 Pneu 2 Pneu 3 FRD1 PAO1 PA14 PAK 37 21% O2 25 37 0% O2 25 21% O2 0% O2 B * Relative viability * * * * * Fig. S2. The effect of anaerobiosis on the elastase secretion of various P. aeruginosa strains including clinical isolates. (A) Strains indicated at the top were grown in LB plus 0.4 % (w/v) NO3- either aerobically (21% O2) or anaerobically (0% O2) for 18 hrs. The level of elastase was analyzed by SDS-PAGE. PA14 and PAK are non-mucoid pathogenic strains, while FRD1 is a mucoid laboratory strain derived from a CF patient. Pneu1, 2 and 3 are non-mucoid isolates from Korean pneumonia patients. (B) MTT cell viability assay of A549 human epithelial cells treated with cell-free culture supernatants (CS) of indicated strains. A549 cells were treated with the same set of CSs as in panel A. Experimental conditions are identical to those described for Fig. 1A. *p<0.01 vs. treatment with anaerobic CS.

3. Table S1. Primers used for qRT-PCR