Figure 2: Effect of sonication time on the concentration of genomic DNA extracted from spores of B. atrophaeus. Each experiment was performed with 230 μL of a purified suspension containing 3.0 × 105 spores mL-1 in PBS. Sonication was performed in continuous (1 × 20 to 1 × 120 s) or intermittent fashion (2 × 10 to 4 × 30 s). For intermittent exposure, sonication and interruption periods were equivalent in time length. The amplitude of the sonicator probe was maintained at 30 μm. DNA concentrations were evaluated using real-time PCR and are shown relative to the average yield obtained with the BD GeneOhmTM Lysis Kit. The number of replicates (n) for bacterial lysis is indicated for each condition on the bar chart. Error bars represent standard deviations.