Thermonuclease Nuc1 expression during biofilm formation. With a competitive Luminex assay, we monitored the presence of thermonuclease Nuc1 (red line, left y axis) in the supernatants of the 1st, 2nd, 4th, and 24th hour during biofilm formation of S. aureus RN6390 (A), Newman (B), M116 (C), and RWW50 (D). Presented are biofilm mass (bar, right y axis) and thermonuclease Nuc1 (red line, left y axis). Significant statistical differences are indicated by asterisks (*, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001). These figures have been generated from three independent experiments. Error bars presented are mean and SEM.