Sperm reception by an egg microvillus in the polychaete,Tylorrhynchus heterochaetus

✍ Scribed by Sato, Masanori ;Osanai, Kenzi

• Book ID: 102890379
• Publisher: John Wiley and Sons
• Year: 1983
• Tongue: English
• Weight: 816 KB
• Volume: 227
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402270315

✦ Synopsis

Abstract

A fine‐structure study of sperm‐egg interactions during normal fertilization in the polychaete Tylorrhynchus heterochaetus was carried out. Sperm initiated an acrosome reaction on the outermost layer of the chorion, which consisted of four layers. After the acrosomal vesicle opened, the subacrosomal space expanded to become a lobular acrosomal process, the frontal margin of which penetrated the first and second layers of the chorion and adhered to the third layer. The process did not penetrate the third and fourth layers. Within 1 min of insemination the acrosomal process of the fertilizing spermatozoon fused with a microvillus projecting from the egg through the chorion. The microvillus thickened and developed into a sperm penetration cone. The sperm nucleus entered the egg cortex through this cone 20–25 min after insemination. The result shows that the tips of egg microvilli are sites for sperm reception.