1,721,061 research outputs found
Cellular localization of PACAP and its receptors in the ovary of the spotted ray Torpedo marmorata Risso 1880 (Elasmobranchii: Torpediniformes).
No full textThe pituitary adenylate cyclase-activating polypeptide (PACAP) is a member of the glucagon-related family and occurs in two amidated forms, PACAP38 and PACAP27, with 38 and 27 amino acids, respectively. PACAP acts by binding to three different receptors, that are classified by their binding affinity for PACAP and VIP (vasoactive intestinal polypeptide): PAC(1) R (PACAP-specific receptor) exclusively binds PACAP, while VPAC(1) R (VIP/PACAP receptor, subtype 1) and VPAC(2) R (VIP/PACAP receptor, subtype 2) bind both PACAP and VIP. PACAP, first discovered in the brain, was then localized in several peripheral tissues of mammals, including the ovary. Besides mammals, PACAP and its receptors have been reported in fish too; however, less is known about the presence of PACAP in the fish ovary and the studies are limited to teleosts. The aim of our work was to study the distribution of the PACAP/PACAP-Rs system in the ovary of the cartilaginous fish Torpedo marmorata. Using in situ hybridization (ISH) and immunohistochemistry techniques, we demonstrated that PACAP and its receptors are widely represented in the Torpedo ovary in a stage-dependent manner. Moreover, our findings suggest an involvement of this peptide in the whole follicologenesis, probably influencing steroidogenesis, follicle development, and oocyte growt
SLOW COOLING OF HUMAN OOCYTES: ULTRASTRUCTURAL INJURIES AND APOPTOTIC STATUS
No full textOBJECTIVE: To identify the damages caused by slow cooling human metaphase II (MII) oocytes comparing the ultrastructure, inner mitochondrial membrane potential (DeltaPsim), and apoptotic status of fresh and cryopreserved oocytes.
DESIGN: Experimental study.
SETTING: University biology research unit and private IVF unit.
PATIENT(S): Fresh and cryopreserved supernumerary MII oocytes donated from women undergoing IVF cycles.
MAIN OUTCOME MEASURE(S): Ultrastructure was assessed by transmission electron microscopy (TEM), mitochondrial function by means of the fluorescent DeltaPsim reporter JC-1, and apoptotic status through fluorescent labeling with the pan-caspase inhibitor fluorescein isothiocyanate conjugate (FITC)-VAD FMK, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling.
RESULT(S): Compared to fresh oocytes, frozen/thawed (F/T) oocytes showed reduced cortical granule densities (F/T 3.35 +/- 1.94/10 microm vs. fresh 10.30 +/- 3.9/10 microm), swelling of smooth endoplasmic reticulum (F/T 0.084 +/- 0.03 microm(2) vs. fresh 0.040 +/- 0.02 microm(2)), decreased electron density of the mitochondrial matrix and damage to the mitochondrial membranes, low DeltaPsim of pericortical mitochondria, but no signs of apoptosis.
CONCLUSION(S): Slow cooling is associated with cortical granule exocytosis, swelling of smooth endoplasmic reticulum vesicles, and mitochondrial damage, but does not induce early or late apoptotic events. The observed injuries might be responsible for the reduced developmental competence of cryopreserved oocytes
The nucleolus and its modifications during oogenesis of Torpedo marmorata
No full textThe structural organisation of the nucleolar apparatus during oogenesis of the spotted ray Torpedo marmorata was investigated. The observations showed that unlike other cartilaginous fishes, in T. marmorata the nucleolar apparatus was always represented by one or two conspicuous nucleoli, whose organization significantly changed during oocyte development. In the smallest follicles (follicles <300 μm in diameter) the nucleolus was made up of granular and fibrillar components, and actively incorporated 3H uridine; later it becomes more and more electron‐dense so in follicles of 400 μm in diameter its components and 3H uridine incorporation were no longer evident. These results indicate that in T. marmorata the nucleolar apparatus significantly changes and undergoes a possible impairment in rRNA synthesis. After nucleolus inactivation, the synthesis of rRNA may be substained by granulos
The Fas/FasL system is a possible regulator of germ cell apoptosis in the testis of Torpedo marmorata
No full textThe role played by the Fas/FasL system in the activation of apoptosis during the spermatogenesis of the spotted ray Torpedo marmorata was investigated. By immunohistochemical and western blot techniques it was demonstrated that the Fas/FasL system is amply represented during spermatogenesis of T. marmorata and it could act both via a paracrine and autocrine route: paracrine at the level of immature and mature cysts, autocrine only in mature cysts
Il testicolo di Torpedo marmorata: un modello per lo studio della spermatogenesi nei vertebrati anamni
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