New ultrastructural observations of human oocyte smooth endoplasmic reticulum tubular aggregates and cortical reaction: update on the molecular mechanisms involved

• Type: Article in International Scientific Journal
• Date: 2016

Authors

sousa, m (Author) ICBAS; Oliveira, E (Author) Other; Barros, N (Author) Other; barros, a (Author) FMUP; Sa, R (Author) Other

Journal

Title: Revista Internacional de Andrologia

Vol. 14

Pages: 113-122

ISSN: 1698-031X

Publisher: Asociacion Espanola de Andrologia

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 4 Citations

Other information

Authenticus ID: P-00M-6QD

DOI: 10.1016/j.androl.2016.04.005

Abstract (EN): Introduction: The ultrastructure of the human mature metaphase-II oocyte before and after the cortical reaction has been previously described. However, we found a new vesicular aggregate associated with smooth endoplasmic reticulum tubular aggregates (aSERT) and new observations regarding the cortical reaction. Objectives: To describe at the ultrastructural level a novel vesicle aggregate associated with aSERT and new observations regarding the cortical reaction. Materials and methods: Donated, surplus mature oocytes were processed for transmission electron microscopy immediately after recover. Calcium detection was performed using the pyroantimonate technique. The cortical reaction was artificially induced by ionophore treatment. Results: We observed an accumulation of small vesicles at the periphery of aSERT. At high magnification these were composed by small pale vesicles coated by tiny vesicles, with associated dense materials, giving a rosette-like appearance. Adjacent to these there was another group of small dense vesicles incompletely coated by similar tiny vesicles. Using calcium detection at the ultrastructural level, antimonate deposits were observed in the tubules of aSERT and in the surrounding mitochondria but not in the rosette-like structures. Regarding cortical vesicles, although most previous studies described their contents as homogeneous dense, others referred the presence of another type of cortical vesicles whose contents were moderate dense. Using ionophore oocyte activation, we observed that moderate dense cortical vesicles may correspond to a progressive swelling of the dense cortical vesicles prior to exocytosis. Conclusions: We describe a novel vesicle aggregate associated to aSERT and new observations on the remodeling of cortical vesicles before exocytosis.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10