Ultrastructural changes during fertilization envelope assembly in Lytechinus pictus eggs revealed by quick-freeze, deep-etch electron microscopy

Nancy M. Mozingo, Douglas E. Chandler

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Morphological features of fertilization envelope assembly in egges from the sea urchin Lytechinus pictus were examind in platinum replicas of samples quick-frozen, deep-etched, and rotary-shadowed at various times after insemination. Unfertilized eggs are surrounded by the vitelline layer, a glycocalyx, which faith-fully follows the contours of the microvillus-studded egg surface. The vitelline layer is secured to the plasma membrane below via a series of short projections called vitelline posts. The vitelline matrix itself is an elaborate meshwork of uniformly sized filaments, which are decorated in places with globular particles. At fertilization, the vitelline layer elevates off the egg surface and by 1 min after insemination appears as a thin, airy network of fibers. In contrast to Strongylocentrotus purpuratus, impressions of the underlying microvilli are not retained in this species. The vitelline template appears to become filled in by the deposition of amorphous secretory material between 1 and 5 min after fertilization. This smooth, amorphous layer is then coated with a thin sheet of paracrystalline material. Paracrystalline coating is incomplete at 5 min, but by 20 min after insemination the coat is complete, consisting of ordered parallel rows of roset-telike particles.

Original languageEnglish (US)
Pages (from-to)271-277
Number of pages7
JournalCell And Tissue Research
Volume271
Issue number2
DOIs
StatePublished - Feb 1 1993

Keywords

  • Fertilization envelope
  • Lytechinus pictus (Echinodermata)
  • Paracrystalline protein
  • Sea urchin eggs
  • Vitelline layer

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology

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