FIG 1.

sRNA-29 causes a reduction in the amount of N₂O produced by P. denitrificans, is predicted to form a complex secondary structure, and is expressed at its highest levels under aerobic conditions in the absence of N₂O emission. (A) Six cultures of P. denitrificans plus empty pLMB509 vector (circles) and 6 cultures of P. denitrificans plus pLMB509 plus sRNA-29 (squares) were grown under denitrification conditions (20 mM nitrate as electron acceptor) for 8 h. Three of 6 of the cultures then had 10 mM taurine added (indicated with an arrow, circles and squares), while the remaining 3 continued to be incubated in the absence of taurine (triangles). N₂O levels were measured. Error bars represent standard deviations (SD) of results obtained between triplicate experiments; where not visible, the error bars were smaller than the symbols. ****, P < 0.0001. (B) The secondary structure was predicted using Mfold. (C) Expression levels are shown relative to the levels expressed under conditions high N₂O emission as reported previously (16).