Hatching envelope formation in the egg of the black tiger shrimp,Penaeus monodon(Decapoda, Penaeidae)

Abstract

The aim of this study was to reveal the process of hatching envelope (HE) formation in eggs of the black tiger shrimp Penaeus monodon, using fluorocytochemistry with fluorescein isothiocyanate (FITC)-labelled lectins and transmission electron microscopy (TEM) with mouse monoclonal anti-FITC-conjugated gold-lectin labelling. Following lectin binding screening tests, Concanavalin A (Con A) and wheat germ agglutinin (WGA) were chosen to trace movements of specific sugar-associated components of the HE. This revealed that both Con A and WGA-binding components migrated from the ooplasm to the HE. Using TEM, it was revealed that membranous materials in the ooplasm were released at the time of spawning, that these became associated with granular structures outside the oocyte and that they together developed into an outer layer of the HE. Contents of flocculent vesicles and dense vesicles in the ooplasm were exocytosed and formed the inner layer of the HE. The TEM with gold-labelled Con A and WGA revealed that the dense and flocculent vesicles and the inner layer of the HE contained components associated with mannose (sugar affinity to Con A) and N-acetyl-β-d-glucosamine (sugar affinity to WGA).