Figure 2.

Gray short-tailed opossum sperm share subflagellar compartmentalization conserved in mammalian species. (A) An adult male gray short-tailed opossum (Monodelphis domestica). (B) A half side of the dissected male reproductive tract from an adult opossum. (C) Confocal images of the opossum epididymal sperm. Paired (left and middle) or single (right) sperm were observed in which PNA staining depicts the location of the acrosome on the anterior head. Hoechst was used for counterstaining. Fluorescence and corresponding DIC images were merged. (D) Scanning electron microscopy images of the opossum sperm. Shown are paired and single sperm (left). Sperm flagella is compartmentalized into midpiece (MP) and principal piece (PP), as shown in the enlarged inset (right). An arrowhead indicates the annulus, a junction between midpiece and principal piece. The magnified region in the right panel shows a longitudinal column (empty arrowheads). H, head. See also Figure S2.