Search results for "sea urchins"
showing 10 items of 135 documents
Manganese interferes with calcium, perturbs ERK signaling, and produces embryos with no skeleton.
2011
Manganese (Mn) has been associated with embryo toxicity as it impairs differentiation of neural and skeletogenic cells in vertebrates. Nevertheless, information on the mechanisms operating at the cellular level remains scant. We took advantage of an amenable embryonic model to investigate the effects of Mn in biomineral formation. Sea urchin (Paracentrotus lividus) embryos were exposed to Mn from fertilization, harvested at different developmental stages, and analyzed for their content in calcium (Ca), expression of skeletogenic genes, localization of germ layer markers, and activation of the extracellular signal-regulated kinase (ERK). By optical and immunofluorescence microscopy, we found…
Isolation and characterization of a Paracentrotus lividus cDNA encoding a stress-inducible chaperonin
2001
Chaperonins are ubiquitous proteins that facilitate protein folding in an adenosine triphosphate–dependent manner. Here we report the isolation of a sea urchin cDNA (Plhsp60) coding for mitochondrial chaperonin (Cpn60), whose basal expression is further enhanced by heat shock. The described cDNA corresponds to a full-length mRNA encoding a protein of 582 amino acids, the first 32 of which constitute a putative mitochondrial targeting leader sequence. Comparative analysis has demonstrated that this protein is highly conserved in evolution.
EMPLOYMENT OF CATIONIC SOLID-LIPID NANOPARTICLES AS RNA CARRIERS
2007
Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. In this article, the suitability of cationically modified solid-lipid nanoparticles (SLN) as a nonviral vector for gene delivery was investigated, in order to obtain stable materials able to condense RNA. Cationic SLN were produced by microemulsion using Compritol ATO 888 as matrix lipid, Pluronic F68 as tenside, and dimethyldioctadecylammonium bromide (DDAB) as cationic lipid. The resulting particles were approximately 100 nm in size and showed a highly positive surface charge (+41 mV) in water. Size and shape were further characterized by scanning electron microscopy (SEM) measurements. M…
PHYSIOLOGICAL AND INDUCED APOPTOSIS IN SEA URCHIN LAEVAE UNDERGOING METAMORPHOSIS
2002
Paracentrotus lividus embryos at the early pluteus stage undergo spontaneous apoptosis. Using a TUNEL (TdT-mediated dUTP Nick-End Labelling) assay on whole mount embryos, we showed that there was a different distribution of the apoptotic cells in different optical sections. Not more than 20% of cells in plutei were spontaneously apoptotic, as confirmed by the counts of dissociated ectoderm and intestine cells. Observation of larva stages closer to metamorphosis confirmed that apoptosis is a physiological event for the development of the adult. In particular, larvae at different developmental stages showed apoptotic cells in the oral and aboral arms, intestine, ciliary band and both apical a…
Effects of cadmium exposure on sea urchin development assessed by SSH and RT-qPCR: metallothionein genes and their differential induction
2012
In order to study the defense strategies activated by Paracentrotus lividus embryos in response to sub-lethal doses of CdCl2, we compared the induced transcripts to that of control embryos by suppression subtractive hybridization technique. We isolated five metallothionein (MT) cDNAs and other genes related to detoxification, to signaling pathway components, to oxidative, reductive and conjugative biotransformation, to RNA maturation and protein synthesis. RT-qPCR analysis revealed that two of the five P. lividus MT (PlMT7 and PlMT8) genes appeared to be constitutively expressed and upregulated following cadmium treatment, whereas the other three genes (PlMT4, PlMT5, PlMT6) are specifically…
Inhibitor of the Cytochrome Oxidase of Unfertilized Sea Urchin Eggs
1960
IN a previous communication1 the presence of an inhibitor of cytochrome oxidase in the unfertilized sea urchin egg was described. It was shown that its activity decreases considerably following fertilization, that it is a low-molecular compound, that it is heat- and alkali-labile and that its action is of a competitive type.
Localization of mitochondrial Hsp56 chaperonin during sea urchin development.
2001
We have previously demonstrated that Paracentrotus lividus nuclear genome encodes for the heat shock inducible chaperonin homolog Hsp 56 (1) and that the mature protein is localized in the mitochondrial matrix (2). In this paper we report that constitutive Hsp56 is maternally inherited, in fact it is present in the in unfertilized eggs, and that it has a perinuclear specific localization during cleavage. In the later stages both the constitutive and the heat shock inducible chaperonin has a specific territorial distribution. Moreover following heat shock, the Hsp56 appears in the cytoplasm and in the postmitochondrial supernatant beside the mitochondrial fraction.
The nucleus negatively controls the synthesis of mitochondrial proteins in the sea urchin egg.
1983
Enucleation of Paracentrotus lividus eggs, followed by parthenogenetic activation induces a sharp increase in the synthesis of mitochondrial proteins as shown by electrofluorography after in vivo labeling with radioactive amino acids. These results further substantiate the hypothesis that the cell nucleus negatively controls mitochondrial replication in the sea urchin egg.
Controlled uptake of PFOA in adult specimens of Paracentrotus lividus and evaluation of gene expression in their gonads and embryos
2023
AbstractPerfluorooctanoic acid (PFOA) has been largely used in the manufacturing industry but a few years ago it turned out to be a dangerous pollutant which is now of concern for terrestrial and aquatic environments. Here, we investigated the bioaccumulation of PFOA in the sea urchin Paracentrotus lividus after exposure to different concentrations of the pollutant for 28 days. We observed rapid uptake of PFOA in the coelomic fluid collected weekly during the exposure period and high bioaccumulation in gonads at the end of the experiment. Interestingly, animals were also able to fast depurate when relocated to a clean environment. In addition, to assess the effect of PFOA on sea urchins’ ph…
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.