Fig 3.

LetA/LetS is dispensable for growth inhibition but required for full induction of motility in response to nicotinic acid treatment. WT (circles), letA (triangles) or letS (squares) L. pneumophila cells containing the flaA-GFP gene reporter were cultured to E phase and then supplemented with water (closed symbols) or 10 mM nicotinic acid (NA; open symbols). At the times indicated, samples were collected and growth was analyzed as OD₆₀₀ (A) and flaA expression as relative fluorescence (B). Similar fluorescence patterns were observed in three independent experiments using two different fluorometers. At time points after 0 h, the OD₆₀₀ values for strains treated with NA were significantly different than those for strains treated with water (P < 0.05).