FIG 6.

Deletion of manL affects release of pyruvate (A to C) and eDNA (D). Strains SK36 (MMZ1896), manL, manLComp, ccpA, and manL ccpA were cultured in TY medium supplemented with 20 mM glucose (A to D) or 10 mM lactose (A). (A) Supernatants from stationary-phase (20-h) cultures of all 5 strains were used in an LDH-catalyzed reaction to measure the pyruvate levels under glucose and lactose conditions. Aliquots of SK36 (B) or the manL mutant (C) were taken at specified time points for measurements of OD₆₀₀ and extracellular pyruvate. (D) Supernatants from stationary cultures of SK36, manL, and manLComp were measured for DNA concentrations using a fluorescent dye. The relative fluorescence units (RFU) are in linear relationship with DNA concentrations within the experimental range. Each result shows the average of three biological repeats, with the error bars denoting standard deviations and asterisks denoting the statistical significance according to Student’s t test (**, P < 0.01; ***, P < 0.001).