Search results for "Oocytes"
showing 10 items of 132 documents
Identification and characterization of a constitutive HSP75 in sea urchin embryos.
1997
Abstract An antiserum against a hsp of the 70-kDa family was prepared, by means of a fusion protein, which was able to detect a constitutive 75-kDa hsc in the sea urchinP. lividus.This hsc was present both during oogenesis and at all developmental stages. A two-dimensional electrophoresis has revealed four isolectric forms of this 75-kDa hsc. The amino acid sequence of the fragment used to prepare the anti-hsp70 antibodies revealed a 43% identity with the corresponding part of sea urchin sperm receptor, and in mature eggs a brighter immunofluorescence was seen all around the cell cortex where the receptor for sea urchin sperm is localized. In oocytes the hsp75 was localized in the cytoplasm…
Beneficial effects of dithiothreitol on relative levels of glutathione S-transferase activity and thiols in oocytes, and cell number, DNA fragmentati…
2006
We analyzed the effect of in vitro aging of mouse oocytes in the presence of dithiothreitol (DTT) on relative levels of glutathione S-transferase (GST) activity and thiols in oocytes, and cell number, DNA fragmentation and cellular allocation to the inner cell mass (ICM) and trophectoderm (TE) lineage at the blastocyst stage. Ovulated oocytes from gonadotropin primed hybrid female mice of 6-8 weeks of age were aged in vitro in the presence of 0, 5, 50, or 500 microM DTT for 6 hr prior to insemination. Relative levels of GST activity and thiols in oocytes were determined by confocal laser scanning microscopy, DNA fragmentation using a single-step TUNEL method, and cell allocation to the ICM …
Deficient membrane integration of the novel p.N14D-GJB2mutant associated with non-syndromic hearing impairment
2006
Mutations in GJB2, the gene encoding for the Gap Junction protein Connexin 26 (Cx26), have been established as the major cause of hereditary, non-syndromic hearing impairment (HI). We report here the identification of a novel point mutation in GJB2, c.40A>G [p.N14D], detected in compound heterozygosity with the c.35delG mutation in two brothers with moderate non-syndromic sensorineural HI. The mother who carried one wildtype and a p.N14D allele displayed normal hearing. The mutation leads to substitution of the neutral amino acid asparagine (N) by the negatively charged aspartic acid (D) at amino acid number 14, a position that is conserved among Cx26 of different organisms and among many o…
Human cationic amino acid transporter hCAT-3 is preferentially expressed in peripheral tissues.
2001
At least five distinct carrier proteins form the family of mammalian cationic amino acid transporters (CATs). We have cloned a cDNA containing the complete coding region of human CAT-3. hCAT-3 is glycosylated and localized to the plasma membrane. Transport studies in Xenopus laevis oocytes revealed that hCAT-3 is selective for cationic L-amino acids and exhibits a maximal transport activity similar to other CAT proteins. The apparent substrate affinity and sensitivity to trans-stimulation of hCAT-3 resembles most closely hCAT-2B. This is in contrast to rat and murine CAT-3 proteins that have been reported to display a very low activity and to be inhibited by neutral and anionic L-amino acid…
Molecular markers for germ cell differentiation in the demosponge Suberites domuncula
2004
Sponges (phylum Porifera) are simple metazoans for which no molecular information on gametogenesis and larval development is available. To support the current study, it was confirmed by histology that oocytes and larvae were produced by the demosponge Suberites domuncula. Three genes/expressed products from S. domuncula whose expression correlated with sexual reproduction were identified and characterized (they are used here as marker genes): i) a receptor tyrosine kinase (RTK) with sequence similarity in the tyrosine kinase domain to fibroblast growth factor receptors; ii) the sex-determining protein FEM1 and iii) the sperm associated antigen (SAA) of triploblasts. Antibodies against the e…
Gamete intrafallopian transfer in the treatment of infertility: the first series at the University of Palermo
1986
Twenty-six couples with unexplained infertility (UI), nine women with repeated failures of artificial insemination with donor semen (AID), three women with mild endometriosis, three with periadnexal adhesions, one with hostile (not immunologic) cervical mucus, and one couple in which the male partner was affected by asthenospermia were treated by the gamete intrafallopian transfer (GIFT) technique. Three different protocols for controlled ovarian hyperstimulation were used, and an adequate follicular growth and oocyte maturation were achieved in all cases. Seventeen pregnancies were obtained, for a global pregnancy rate of 38.6%. Two pregnancies (11.7%) ended in clinical abortions, and one …
Consequences on offspring of abnormal function in ageing gametes.
2000
The present review aims to analyse (i) the molecular, biochemical and cellular changes that accompany oocyte and sperm ageing in any of the internal or external environments where they can reside, and (ii) the consequences of the abnormal function in ageing gametes on pre- and post-implantation development and later life of offspring. This review also aims to propose and discuss cellular/molecular mechanisms framed within the 'free radical theory of ageing'. It appears that the ageing of gametes prior to fertilization may affect many molecular, biochemical and cellular pathways that may jeopardize not only pre- and post-implantation embryo/fetal development but also later life of offspring.…
New molecular markers for the evaluation of gamete quality.
2013
Purpose: Only 30 % of IVF cycles result in a pregnancy, so that multiple embryos need to be replaced, per treatment cycle, to increase pregnancy rates, resulting in a multiple gestation rate of 25 %. The use of new markers in the gamete selection, could reduce the number of the oocytes to be fertilized and embryos to be produced, but the tools to evidence the gamete competence remain unavailable and more studies are needed to identify bio-markers to select the best oocyte and sperm to produce embryos with higher implantation potentiality. Methods: To define oocyte competence, the apoptosis of the surrounding cumulus cells and the oxygen consumption rates for individual oocytes before fertil…
Oral administration of pharmacological doses of Vitamins C and E reduces reproductive fitness and impairs the ovarian and uterine functions of female…
2002
This study aims to ascertain whether oral administration of pharmacological doses of Vitamins C and E has any detrimental effect on reproductive fitness of female mice. We fed hybrid female mice from the first day of weaning a standard diet supplemented or not supplemented with pharmacological doses of Vitamins C and E. At the age of 28 weeks, we individually caged females with a male for the rest of their reproductive life. We performed a series of mating experiments to ascertain the number of oocytes ovulated and the potential for embryo development in vitro to the blastocyst stage and in vivo to Day 12 of gestation. The antioxidant diet decreased the frequency of litters, litter size, to…
The polychaete Platynereis dumerilii (Annelida): a laboratory animal with spiralian cleavage, lifelong segment proliferation and a mixed benthic/pela…
2004
Platynereis dumerilii, a marine polychaetous annelid with indirect development, can be continuously bred in the laboratory. Here, we describe its spectacular reproduction and development and address a number of open research problems. Oogenesis is easily studied because the oocytes grow while floating in the coelom. Unlike the embryos of other model spiralians, the Platynereis embryo is transparent giving insight into the dynamic structures and processes inside the cells that accompany the prevailing anisotropic cleavages. Functional studies on cell specification and differential gene expression in embryos, larvae, and later stages are underway. Lifelong proliferation of uniform trunk segme…