Search results for " sea urchin"

Molecular approaches to elucidate the early response of P. lividus embryos to sublethal Cadmium exposition.

2011

cis-Regulatory sequences driving the expression of the Hbox12 homeobox-containing gene in the presumptive aboral ectoderm territory of the Paracentro…

2008

AbstractEmbryonic development is coordinated by networks of evolutionary conserved regulatory genes encoding transcription factors and components of cell signalling pathways. In the sea urchin embryo, a number of genes encoding transcription factors display territorial restricted expression. Among these, the zygotic Hbox12 homeobox gene is transiently transcribed in a limited number of cells of the animal-lateral half of the early Paracentrotus lividus embryo, whose descendants will constitute part of the ectoderm territory. To obtain insights on the regulation of Hbox12 expression, we have explored the cis-regulatory apparatus of the gene. In this paper, we show that the intergenic region …

Characterization of a nuclear factor associated to the chromatin of sea urchin histone genes

2007

A method for measuring mitochondrial mass and activity

2007

Mitochondria, responsible for the energy-generating process essential for the cell metabolism, differ for the number, localization and activity in animal cells and tissues in relation to the energetic needs. Using fluorescent probes specific for mitochondria, Mitotracker Green (MTG) and Orange (MTO), and Confocal Laser-Scanning Microscope (CLSM), we elaborated a method to measure in vivo the mitochondrial mass and activity, in sea urchin Paracentrotus lividus eggs and embryos. The analysis of captured images, revealed a variation of mitochondrial distribution and an increase of activity after fertilization.

A constitutive 70 kDa heat-shock protein is localized on the fibres of spindles and asters at metaphase in an ATP-dependent manner: A new chaperone r…

2001

In the present study, double immunofluorescence and immunoblot analysis have been used to show that centrosomes, isolated from Paracentrotus lividus sea urchin embryos at the first mitotic metaphase, contain the constitutive chaperone, heat-shock protein (HSP) 70. More specifically, we demonstrate that centrosomes contain only the HSP70-d isoform, which is one of the four isoforms identified in P. lividus . We also provide evidence that p34(cell division control kinase-2) and t complex polypeptide-1 (TCP-1) α, a subunit of the TCP-1 complex, are localized on the centrosomes. Furthermore, inhibition of TCP-1 in vivo, via microinjecting an anti-(TCP-1α) antibody into P. lividus eggs before fe…

TOXICITY INDUCED BY GADOLINIUM IONS ON DEVELOPING SEA URCHIN EMBRYOS

2016

Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a metal of the lanthanide series of the elements whose chelates are commonly employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the effects of exposure to sublethal Gd concentrations on the development of four phylogenetically and geographically distant species: two Mediterranean species, Paracentrotus lividus and Arbacia lixula, and two species living in the East coast of Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Measures of the Gd and Ca content inside embryos by ICPMS showed a time- and dose-depend…

The toxic effect of gadolinium ions on sea urchin embryos: comparison among phylogenetically distant species and focus on mechanisms regulating stres…

2016

Gadolinium (Gd) is a metal of the lanthanide series of the elements whose chelates are commonly employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the consequences of sea urchin embryo exposure to sublethal Gd concentrations, comparing the effects on the development of four phylogenetically and geographically distant species: two Mediterranean species, Paracentrotus lividus and Arbacia lixula, and two species living in the East coast of Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Measures of the Gd content inside embryos by ICP-MS showed a time- and dose-dependent increase. In all these s…

Confocal microscopy study of the distribution, content and activity of mitochondria during Paracentrotus lividus development

2007

Summary In the present paper we applied confocal microscopy andfluorescence technologies for studying the distribution andthe oxidative activity of sea urchin ( Paracentrotus lividus )mitochondria during development, by in vivo incubating eggsand embryos with cell-permeant MitoTracker probes. Wecalculated, by a mathematical model, the intensity values, the variations of intensity, and the variation index of incorporatedfluorochromes. Data demonstrate that mitochondrial massdoes not change during development, whereas mitochondrialrespirationincreases.Inaddition,startingfrom16blastomeresstage, some regions of the embryo contain organelles moreactive in oxygen consumption. Introduction The con…

EGFR signalling is required for Paracentrotus lividus endomesoderm specification

2008

The EGFR pathway is critical for cell fate specification throughout the development of several organisms. Here we identified in sea urchin an EGFR-related antigen maternally expressed and showing a dynamic pattern of localization during development. To investigate the role played by the EGFR in Paracentrotus lividus development we blocked its activity by using the EGFR kinase inhibitor AG1478. This treatment produces decrease of EGFR phosphorylation, and embryos with various defects especially in the endomesoderm territory until to obtain an animalized phenotype. These effects are rescued by the addition of TGF-alpha, an EGFR ligand. The role played by EGFR-like along the animal/vegetal axi…

Ectopic hbox12 Expression Evoked by Histone Deacetylase Inhibition Disrupts Axial Specification of the Sea Urchin Embryo

2015

Dorsal/ventral patterning of the sea urchin embryo depends upon the establishment of a Nodal-expressing ventral organizer. Recently, we showed that spatial positioning of this organizer relies on the dorsal-specific transcription of the Hbox12 repressor. Building on these findings, we determined the influence of the epigenetic milieu on the expression of hbox12 and nodal genes. We find that Trichostatin-A, a potent and selective histone-deacetylases inhibitor, induces histone hyperacetylation in hbox12 chromatin, evoking broad ectopic expression of the gene. Transcription of nodal concomitantly drops, prejudicing dorsal/ventral polarity of the resulting larvae. Remarkably, impairing hbox12 …