FIG. 4.

Lipolytic activities of wild type, plaB mutant, and genetically complemented L. pneumophila strains. Culture supernatants (A) and cell lysates (B) of wild type, plaB mutant, and genetically complemented L. pneumophila strains were incubated with DPPG, DPPC, MPLPG, MPLPC, or 1-MPG for 2 h (A) or 30 min (B) at 37°C, and then the release of FFA was quantified. In some cases, culture supernatants or cell lysates were diluted with lipids as indicated prior to incubation. Data are expressed as differences between the amount of FFA released by the culture supernatant or cell lysate and the amount released by uninoculated BYE broth or Tris-HCl buffer, respectively. Results are means and standard deviations from duplicate cultures and are representative of three independent experiments.