Search results for "sea urchin."
showing 10 items of 317 documents
Cellular and molecular bases of biomineralization in sea urchin embryos
2013
Sea urchin embryos construct their skeleton following a precise gene-regulated time- and space-dependent programme, in concert with factors promoting cell adhesion and differentiation. The biomineral is deposited in a privileged extracellular space produced by the fused filopodia processes of the primary mesenchyme cells, the only cells producing a set of necessary matrix proteins. More than ten years ago we showed for the first time that signals from ectoderm cells promoted the expression of one of the major skeleton matrix genes by the primary mesenchyme cells. Since then, many of the crucial steps of this complex activation cascade, from ectoderm cells to embryonic spicules, have been el…
Autophagy as defence strategy against cadmium stress in Paracentrotus lividus embryos.
2009
Sea urchin embryo is a developmental model that offers an excellent opportunity to investigate the possible adaptive response of cells exposed to different stress during differentiation. These embryos are able to respond to many stress by synthesizing a set of highly conserved proteins, the hsps and/or by activation of apoptosis. The exposure to cadmium trigger the accumulation of metal in embryo cells and the activation of both defence mechanisms depending on concentration and exposure time [1-4]. Recent experimental evidences demonstrate that by autophagy, a highly regulated mechanism that enhances cell survival under various environmental and cellular stress, the breakdown and recycling …
A possible role of autophagy for the execution of apoptosis in cadmium-exposed sea urchin embryos
2012
The sea urchin embryo is a suitable model system that offers an excellent opportunity to investigate different defence strategies activated in stress conditions. We previously showed that cadmium treatment provokes the accumulation of metal in dose- and time-dependent manner in embryonic cells and the activation of defence systems, such as the synthesis of HSPs and/or the initiation of apoptosis. Analysing autophagy, by neutral red, acridine orange and LC3-detection, we demonstrated that Cd-exposed embryos adopt this process as an additional stratagem to safeguard the developmental program. We observed that embryos treated with subletal Cd concentration activate a massive autophagic respons…
Sea urchin embryo as a model system for studing autophagy induced by cadmium stress
2010
Localization of HSP70, Cdc2, and cyclin B in sea urchin oocytes in non-stressed conditions.
2003
In Paracentrotus lividus embryos, a Mediterranean sea urchin species, HSP70 is present in all the cells. During cell division it localizes under normal growth conditions on the centrosomes and on the whole isolated mitotic apparatus. Now, in situ hybridization, Western blot analyses, and immunohistochemistry show that the HSP70 mRNA is present in both small and large P. lividus oocytes, that all four isoforms of HSP70 can be found also in the oocytes, and that a certain amount of HSP70 localizes on asters and spindles during polar body formation. Moreover, two representative cell-cycle related proteins, cyclin B, and Cdc2, are present both in small and large oocytes, concentrating in the ge…
A survey on tubulin and arginine methyltransferase families sheds light on p. lividus embryo as model system for antiproliferative drug development
2019
Tubulins and microtubules (MTs) represent targets for taxane-based chemotherapy. To date, several lines of evidence suggest that effectiveness of compounds binding tubulin often relies on different post-translational modifications on tubulins. Among them, methylation was recently associated to drug resistance mechanisms impairing taxanes binding. The sea urchin is recognized as a research model in several fields including fertilization, embryo development and toxicology. To date, some &alpha
The effects of recreational Paracentrotus lividus fishing on distribution patterns of sea urchins at Ustica Island MPA (Western Mediterranean, Italy)
2006
This study evaluated the effects of recreational Paracentrotus lividus fishing on average density and size of this edible sea urchin, and its indirect effects on Arbacia lixula on barren substrates of Ustica Island MPA (SW Italy, Mediterranean Sea). Size, single and pooled species densities, density of large individuals (>40 mm long) and small individuals (<20 mm long) of the two species were estimated by scuba diving in autumn 2003, spring and summer 2004 at two sites impacted by P. lividus fishing (Punta Cavazzi and Pagliaro, take zone C) and one control (Cala Sidoti, no take zone). Two samplings were performed in each season. We found that reduced densities of P. lividus and A. lixula oc…
Sequence analysis of the rDNA spacer of Paracentrotus lividus and observations about pre-rRNA processing. NTS sequence of Paracentrotus lividus rDNA.
1993
We have isolated and sequenced one intergenic region and a small part of the flanking regions (18S and 26S rRNA coding regions) of the rRNA-encoding genes (rDNA) from the sea urchin Paracentrotus lividus. This region is about 3.8 Kb long. Northern blot hybridizations and S1 mapping experiments demonstrated the presence of a partially processed 21S rRNA precursor while has the same 5' terminus as the 32S primary precursor, also in developmental stages characterized by a low rate of rRNA synthesis.
Relazione tra autofagia e apoptosi in embrioni di riccio di mare esposti a stress
2012
L’embrione di riccio di mare Paracentrotus lividus è stato utilizzato come organismo modello della biologia dello sviluppo per molti anni ed è considerato il deuterostoma più primitivo, con scheletro calcificato, correlato a protocordati e vertebrati. Tale sistema offre un'eccellente opportunità per studiare le numerose strategie di difesa che gli embrioni mettono in atto contro diverse condizioni di stress. In precedenza, abbiamo riportato che l’esposizione di embrioni a dosi citotossiche di cadmio, provoca l'accumulo intracellulare del metallo e l'attivazione del sistema difensivo, in modo dose-tempo dipendente, attraverso la sintesi di specifiche HSPs e/o l’innesco di apoptosi. Mediante …