2.1. Conventional transmission electron microscopy
Testicular tissues were dissected out from snails. The
tissue was fixed with 2.5% glutaraldehyde in 0.05M cacodylate
buffer at 4 ◦C for 6 h, washed thoroughly in the
same buffer, and was post-fixed with 1% osmium tetroxide
in the same buffer. The fixed tissue was dehydrated
with graded series of ethanol and embedded in epoxy
resin. Ultra-thin sections were cut on an ultratome (MT-
2C, RMC) with a diamond knife. After double staining
with uranyl acetate and lead citrate, the sections were observed
with an electron microscpe (JEM-2000EX, JEOL) at
80 kV.