Figure 1: Significance of trypsin digestion for dissociating DNA fibers from nuclear DNA–binding components. The results shown in Figures 1–6 were obtained by using sperm prepared as described below using the ejaculate (vol.=4.4 mL, conc.=76 x 106 sperm/mL, motility=59%), the precipitate of the density–gradient (200 μL, 370 x 106 sperm/mL, 78%), and the swim–up fraction (1.0 mL, 31 x 106 sperm/mL, 97%). Asthenozoospermic semen was defined by 3.8 mL, 46 x 106 sperm/mL, and 3.6%. The purified sperm with progressive motility were suspended in 30 mM Tris–HCl, 0.05% Triton X–100, 5.0 mmol/L DTT, x 104 diluted Cyber–Gold containing 2.0 mol/L NaCl (A) or 8.2 mmol/L hexa–metaphosphate Na (B), respectively. C: one–tenth volume of Trypsin (20 μg/mL) was subsequently added to the above specimen A. The scale bar shown in the figures 1, 2 and 5–7 represented 20 μm, and those in the figures 3 and 4 were 10 μm.