Germ cells and fertilization: why I studied these topics and what I learned along the path of my study

Chemical and physical guidance of fish spermatozoa into the egg through the micropyle†,‡

“…For eggs of some fish that were not adhesive or floated in water (e.g., zebrafish, medaka), glass or plastic dishes were coated with poly-l-lysine [13] to facilitate attachment of the eggs to dishes. Alternatively, a group of eggs or mechanically isolated chorions in a drop of Ringer's were mounted between a slide and a coverslip that was supported with four dots of vaseline-paraffin-bee's wax (9: 1: 0.5) mixture [14]. Eggs were compressed slightly under the coverslip before searching for an egg with a clearly visible micropyle under a 40x ordinary objective lens.…”

“…These reagents are known to increase intracellular Ca 2+ levels. To test the effects of these agents, a slide glass with four small dots of vaseline-paraffin mixture was prepared [14]. After a small drop (1 μl) of milt was placed at the center of the four vaseline dots, a coverslip with hanging seawater (for herring and flounder) or 1/100 Ringer's (for trout) with or without the above reagents was laid on the vaseline dots.…”

Lessons learned in Andrology: revelations on a road less traveled

“…We have a very active program on sperm cell biology in a range of species from horses to duck-billed platypi and Mark, in particular, has been instrumental in pioneering the use of mass spectrometry to understand the fundamental biochemistry of these cells. In addition, we have had a lot of fun recently working on the developmental biology of a range of sub-mammalian species including annelid worms, oysters and fish, just as Yana described in his Lessons-in-Andrology article (Yanagimachi, 2014).…”