Figure 7.

Quantification of total polyamine production in tested strains and a model that depicts the multilayered role of DksA1. A, polyamine production in bacterial strains. Total polyamines, including putrescine, spermine, and spermidine, were measured from 100 mg of bacterial cell pellets. The values of means ± S.D. (error bars) are presented (n = 3). *, p < 0.05 versus values in PAO1. B, potential roles of DksA1 in P. aeruginosa. When DksA1 is absent (bottom half), the metabolic flow of SAM leads to elevated polyamine synthesis, inhibiting the synthesis of autoinducers. In addition to its well-characterized role in activating stringent response, DksA1 also participates in regulation of anaerobic respiration and motility.