FIG. 6.

Continued. stained sperm nucleus; a8) dual bright-field/fluorescence image of PNA-stained anterior acrosome; a9) dual bright-field/fluorescence image of SPESP1-positive domain confined to equatorial segment; a10) dual SPESP1 and DAPI; a11) dual DAPI and PNA; a12) dual SPESP1 and PNA-positive revealing distinct segregation of PNA and SPESP1 domains. Bar = 10 μm (a1–a6) and 5 μm (a7–a12). b) Capacitated, acrosome-reacted sperm: b1) bright field; b2) green immunofluorescent SPESP1 domain confined to equatorial segment in each cell, albeit at lower intensity than in acrosome-intact sperm (a series above); b3) SPESP1 and PNA staining reveals absence of red staining anterior acrosome in acrosome-reacted sperm; b4) DAPI staining alone; b5) DAPI