Search results for "sea urchin embryo."
showing 10 items of 70 documents
Phosphoproteinphosphatase activity in sea urchin embryos
1964
Si e studiata l'attivita fosfoproteinfosfatasica in omogenati totali di uova ed embrioni diParacentrotus lividus e diArbacia lixula. La reazione ha un optimum a pH acido, e stimolata da K+ e Na+ ed e inibita da Ca++ e Mg++. L'attivita enzimatica aumenta tra la fecondazione e lo stadio a 64 blastomeri; in seguito rimane costante fino a blastula con mesenchima; quindi generalmente decresce.
Aggregation of cells isolated from vegetalized and animalized sea urchin embryos
1963
Blastule diParacentrotus lividus trattate con LiCl (vegetalizzate) o con ZnSO4 (animalizzate) sono state disaggregate con la tecnica precedentemente descritta. Le cellule da blastule vegetalizzate si riaggregano in masse solide che non differenziano ne scheletro ne intestino. Quelle da blastule animalizzate danno origine a vescicole ciliate. Tentativi di combinazione di cellule da blastule animalizzate e vegetalizzate in un caso hanno dato origine ad aggregati con abbozzi di scheletro.
Symmetry Breaking and Establishment of Dorsal/Ventral Polarity in the Early Sea Urchin Embryo
2015
The mechanisms imposing the Dorsal/Ventral (DV) polarity of the early sea urchin embryo consist of a combination of inherited maternal information and inductive interactions among blastomeres. Old and recent studies suggest that a key molecular landmark of DV polarization is the expression of nodal on the future ventral side, in apparent contrast with other metazoan embryos, where nodal is expressed dorsally. A subtle maternally-inherited redox anisotropy, plus some maternal factors such as SoxB1, Univin, and p38-MAPK have been identified as inputs driving the spatially asymmetric transcription of nodal. However, all the mentioned factors are broadly distributed in the embryo as early as no…
Marine Invertebrates as Bioindicators of Heavy Metal Pollution
2014
Atmosphere, earth and water compose the environment. The presence of heavy metals in the environment has grown because of their large employment in some industrial and agricultural activities. Although these metals are terrestrial products, they flow into the sea through effluents and sewage or are directly discharged from industries placed on the seawater front. It should be considered that metals concentrations vary widely according to different seawater latitudes and depths and can be strongly influenced by fresh water discharges from heavily polluted rivers. In this review recent studies on heavy metal pollution in marine ecosystems and their organisms will be presented. Metal speciatio…
Sea urchin embryos exposed to cadmium as an experimental model for studying the relationship between autophagy and apoptosis
2014
The sea urchin embryo is a suitable model that offers an excellent opportunity to investigate different defence strategies activated in stress conditions. We previously showed that cadmium accumulates in a dose- and time-dependent manner into embryonic cells, activating different stress and defence mechanisms, including the synthesis of HSPs and the onset of apoptosis and/or autophagy. In this paper we investigated the functional relationship between autophagy and apoptosis, evaluating apoptosis signals in cadmium-exposed Paracentrotus lividus embryos with inhibited autophagy. We found that the inhibition of autophagy produced the concurrent reduction of apoptosis, suggesting that the two p…
2 Genes and Their Products in Sea Urchin Development
1999
Publisher Summary This chapter focuses on the genes and their products in sea urchin development. Sea urchin embryos were among the first eukaryotes in which regulation of gene expression was studied and still represent one of the main developing systems for which most of the literature has accumulated in the past and also in recent years. The interest in the subject has, however, shifted from the molecular biology field—that is, from the study of the mechanisms of regulation of gene expression—to a field in which the role of genes and their products on development is being considered. The study of the synthesis of histones has served the purpose of trying to understand the mechanisms, unde…
Strategie di difesa attivate in risposta a stress, in embrioni di Paracentrotus lividus
2012
Sea urchin embryos are able to activate different defense strategies against stress. This model system allows to investigate numerous phenomena in multipotent cells, which interact among themselves, in their natural position, bypassing the disadvantages of isolated cells, deprived of their normal network. Cadmium (Cd) treatment triggers the accumulation of metal in embryonic cells and the activation of defense systems depending on concentration and exposure time, through the synthesis of heat shock proteins and/or the initiation of apoptosis. Here we show that Paracentrotus lividus embryos exposed to subacute/sublethal concentrations of Cd adopt autophagy as an additional stratagem to safeg…
Toxicity induced by Gadolinium ions on sea urchin embryos: comparison among phylogenetically distant species and focus on stress response and skeleto…
2016
Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a lanthanide metal whose chelates are 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 sea urchin species: two Mediterranean, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Sensitivity to Gd greatly varied, with EC50 ranging from 56 nM to 132 µM across the four species. Measures of the Gd and Ca content inside embryos showed a…
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 …