A thick layer surrounding a mammalian egg, which the sperm must penetrate via an enzymatic reaction in order to fuse with the egg membrane and fertilize the egg. Japanese scientists recently discovered a protein (dubbed "Izumo" after a Japanese shrine dedicated to marriage) without which mouse sperm could not fuse with a mouse egg membrane. A similar protein has been identified in human sperm, hinting at possible methods of non-hormonal contraception.
posted on Wed, 09 Mar 2005 at 15:33 | path: /words | perma link
