FIG 4.

NO pretreatment induces the expression of fhp. P. aeruginosa PAO1 was grown in multiwell plate batch cultures for 3 h before being treated or not with 10 μM SP-NO. After 15 min, mRNAs were extracted from biofilm and planktonic bacteria, and fhp mRNA levels were quantified by qRT-PCR analysis. The data show fold changes in fhp transcript levels relative to untreated planktonic cells. The error bars indicate standard deviations (n = 3). The asterisks indicate statistically significant differences between samples as indicated (**, P < 0.01; ***, P < 0.001).