FIG 1.

Efficiency of microbial cell lysis in subseafloor sediments after DNA extraction. Sediments from 2H-2 (9.5 mbsf [meters below the seafloor]) (A), 5H-1 (35.4 mbsf) (B), 10H-1 (84.0 mbsf) (C), 20H-3 (177.4 mbsf) (D), and 40H-10 (364.0 mbsf) (E) from offshore of the Shimokita Peninsula and 3H-6 (22.0 mbsf) (F) from the Nankai Trough in Japan were treated with alkaline lysis solution at 50, 70, 90, or 98°C for 20 min, and the lysis efficiencies were determined with bead beating using a commercial kit (PowerMax soil DNA isolation kit [PM] or FastDNA spin kit for soil [FP]). The lysis percentage was calculated by enumerating cells before and after extraction. Error bars show standard deviations of at least triplicate measurements of triplicate extractions.