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Your search keyword '"José A. Cebrian-Perez"' showing total 3 results
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3 results on '"José A. Cebrian-Perez"'

1. New method for the treatment of sperm samples for ultrastructural study based on the use of animal tissues as biological containers

Author

Concepción Junquera, Carmen Colás, Carmen Martínez-Ciriano, Pedro Serrano, Tomás Castiella, José A. Cebrian-Perez, and Teresa Muiño-Blanco

Subjects
Male, Medical Laboratory Technology, Histology, Sheep, Microscopy, Electron, Transmission, Animals, Microtomy, Anatomy, Instrumentation, Chickens, Spermatozoa, Specimen Handling
Abstract

The study of the ultrastructure of spematozoa by means of transmission electron microscopy (TEM) often presents with problems of interpretation according to the method employed, depending on whether samples are either centrifuged previously to the fixation or immersed in viscous gels. The major problems of interpretation are changes in the location of vesicles originated during the maturation process and modifications in the adsorption of seminal plasma proteins to the sperm membrane surface. The aim of our study is to communicate an original new method for the treatment of spermatozoa for ultrastructural study. Our method is based on the use of animal tissues as biological containers, inside which the spermatic suspensions are included. We developed this method using fresh sperm samples taken from mature Rasa Aragonesa rams. As biological container, we used 2.5-cm long segments of the intestine of 1-week-old chickens (Gallus gallus) (diameter around 4 mm). In order to avoid any influence of digestive enzymes of the mucosa on the sperm surface, we put each intestine fragment inside out by means of microdissection forceps under a bifocal optical microscope and cold light. One of the edges was tied with thin suture silk. The sperm suspension was injected in the optimal experimental condition and amount. Finally, the still-open edge of the intestine segment was tied with silk in the same way as the other segment edge. By using this technique, we can perform a suitable morphological study at an ultrastructural level. In addition, the functional relationship of the ultrastructural components of the target cells is correctly preserved.

Published
2007

2. Cyclic-AMP initiates protein tyrosine phosphorylation independent of cholesterol efflux during ram sperm capacitation.

Author

Carmen Colas, Peter James, Liz Howes, Roy Jones, José A. Cebrian-Perez, and Teresa Muiño-Blanco

Subjects
CYCLIC adenylic acid, PROTEIN-tyrosine kinases, PHOSPHORYLATION, BLOOD cholesterol, SPERMATOGENESIS, PHOSPHODIESTERASES, CYCLODEXTRINS, RAMS, REPRODUCTION
Abstract

Unlike most other species, ram spermatozoa are difficult to capacitate in vitro. Bicarbonate and Ca2+ are necessary, whereas bovine serum albumin does not appear to be obligatory. In the present investigation we have assessed (1) the ability of the cholesterol-sequestering agent, methyl-β-cyclodextrin (M-β-CD), to initiate protein tyrosine phosphorylation, and (2) the importance of phosphodiesterases (PDEs) in controlling the levels of cAMP. Results show that despite removing significant amounts of membrane cholesterol, as assessed by filipin staining, M-β-CD treatment did not stimulate major increases in protein tyrosine phosphorylation. Addition of a cocktail of PDE inhibitors (theophylline and caffeine), a phosphatase inhibitor (okadaic acid) and dibutyryl-cAMP (db-cAMP), however, stimulated specific tyrosine phosphorylation of several proteins between 30 and 120 kDa. On their own, none of the above reagents were effective but a combination of db-cAMP + PDE inhibitors was sufficient to achieve a maximal response. H-89, a protein kinase-A inhibitor, suppressed tyrosine phosphorylation significantly. Immunofluorescence revealed that the newly-phosphorylated proteins localised mainly in the sperm tail. These findings suggest that in ram spermatozoa cAMP levels are too low to initiate tyrosine phosphorylation of flagellar proteins that are indicative of the capacitation state and that this is caused by unusually high levels of intracellular PDEs. [ABSTRACT FROM AUTHOR]

Published
2008
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3. Sperm quality and seminal plasma proteins in three sheep breeds under high altitude and tropical conditions

Author

Melissa Carvajal-Serna, Jaime A. Cardozo, Henry Grajales-Lombana, José A. Cebrián-Pérez, and Teresa Muiño-Blanco

Subjects
antioxidant defense enzymes, high-tropic, rainy season, Agriculture
Abstract

We tested the hypothesis that sheep breed can influence the sperm quality and seminal plasma (SP) composition and investigated any potential relationship between SP proteins and antioxidant enzyme activities (AO) with sperm quality. Ejaculates from twelve rams of three breeds were obtained during the rainy season at high altitudes, and sperm quality was automatically evaluated (CASA-Hamilton Thorne). The AO of superoxide dismutase, glutathione peroxide and glutathione reductase (GR) in SP was evaluated and total proteins were separated by SDS-PAGE. Comparative analyses of semen quality parameters between breeds revealed that Creole and Hampshire breeds had a higher sperm quality compared with Romney Marsh (p

Published
2018
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