Search results for " SEA URCHIN"

p38 MAPK activation is required for Paracentrotus lividus skeletogenesis

2008

We investigated the p38 MAPK role during sea urchin, Paracentrotus lividus, development. We found that at the morula stage, before the onset of skeletogenesis, p38 MAPK shows a peak of activity, and we tested whether p38 MAPK activity has any effect on skeletogenesis. By immunohistochemistry on whole-mount embryos we show the preferential localization of the active p38 form both in the presumptive PMCs and bilateral spiculo- genesis centers in control embryos, and in the radialized supernumerary spiculogenesis centers induced by NiCl2 treatment. By using SB203580, a p38 MAPK specific inhibitor, we show that p38 activity is required both for the initial triradiate spicule rudiments formation…

Relative role of fish vs. starfish predation in controlling sea urchin populations in Mediterranean rocky shores

2009

In the Mediterranean, fishing bans generally allow the recovery of populations of sea urchin predators, such as the seabreams Diplodus sargus and D. vulgaris, promoting the transformation of overgrazed communities into ones dominated by erect macroalgae. However, in the marine reserve on Ustica Island (SW Italy) the opposite trend has occurred in the upper infralittoral community, and urchin barrens formed after the cessation of fishing activities. We hypothesized that (1) the natural scarcity of the 2 seabream species leads to a low predation rate on sea urchins at Ustica, and (2) predation rate varies with depth, due to differences in the predator assemblages. Tethering experiments were c…

A FOX Binding Site is Necessary for the Activation of Pl-Tuba1a Gene in the neurogenic domains

2016

All echinoderm larvae possess a nervous system consisting of a ciliary band and associated sensory ganglia (apical, oral and lateral ganglia) that controls swimming and feeding. Neurons of the larval nervous system first appear as neuroblasts in the thickened ectoderm of the animal plate (anterior neuroectoderm, ANE) at the late blastula – early gastrula stage and then also in the ciliary band. The neural differentiation process of sea urchin embryos has been analysed and the Gene Regulatory Network involved in the differentiation processes is extensively studied. We have previously isolated an alpha tubulin family member of the sea urchin Paracentrotus lividus (Pl-Tuba1a, formerly known as…

Vanadium perturbs the fertilization outcome and the metalloproteinase activity in sea urchin embryos

2021

Metal toxicology represents a current major topic due to the disper- sion of these elements in the environment. Metals are released from both natural sources and industrial activities. Some of them have also a clinical interest due to their application as metallodrugs (i.e., Pt, Cu, Au, Ru, and Y) or in medical diagnosis (Gd).1,2 Recently, V derivatives are considered as potential therapeutic factors in some diseases (e.g., obesity, diabetes, cancer, neurodegenerative and heart disorders). As a consequence, pharmaceutical residues could repre- sent emerging pollutants of aquatic environments, as wastewater treatment plants do not sufficiently remove these compounds3. Embryonic models repres…

The Sea Urchin sns Insulator Blocks CMV Enhancer following Integration in Human Cells

2001

Insulators are a new class of genetic elements that attenuate enhancer function directionally. Previously, we characterized in sea urchin a 265-bp-long insulator, termed sns. To test insulator activity following stable integration in human cells, we placed sns between the CMV enhancer and a tk promoter up-stream of a GFP transgene of plasmid or retroviral vectors. In contrast to controls, cells transfected or transduced with insulated constructs displayed a barely detectable fluorescence. Southern blot and PCR ruled out vector rearrangement following integration into host DNA; RNase protection confirmed the enhancer blocking activity. Finally, we demonstrate that two cis-acting sequences, p…

Bioactive molecules from soil and marine bacteria: new potential applications

2015

CELLULAR AND MOLECULAR MECHANISMS ACTIVATED IN SEA URCHIN EMBRYOS EXPOSED TO GADOLINIUM, EMERGING ENVIRONMENTAL CONTAMINANT

On hidden heterogeneity in directional asymmetry – can systematic bias be avoided?

2006

8 pages; International audience; Directional asymmetry (DA) biases the analysis of fluctuating asymmetry (FA) mainly because among-individual differences in the predisposition for DA are difficult to detect. However, we argue that systematic bias mainly results from predictable associations between signed right-left asymmetry and other factors, i.e. from systematic variation in DA. We here demonstrate methods to test and correct for this, by analysing bilateral asymmetry in size and shape of an irregular sea urchin. Notably, in this model system, DA depended significantly on body length and geographic origin, although mean signed asymmetry (mean DA) was not significant in the sample as a wh…

Effect of environmental stress on sea urchin embryos and larvae: from developmental to molecular biology analyses

2010

Identification of GABA receptor genes and evidence of GABA signaling during embryogenesis of the sea urchin

2012

Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the mammalian central nervous system and acts via ionotropic (GABAA-Rs) and metabotropic (GABAB-Rs) receptors. GABAA-Rs are Cl- selective hetero-pentameric channels assembled by combinations of 19 distinct gene products. Instead, GABAB-Rs are bi-subunit G-protein coupled receptors linked to K+ or Ca2+ channels. Dysfunctions of GABA-signaling (GS) cause psychotic disorders and correlate with epigenetic alterations, such as over-expression of DNA methyl transferase-1 which in turn imposes iper-methylation of GABA-regulated genes. The sea urchin embryo, which presents a rudimentary nervous system, offers a big oppor…