Search results for "Paracentrotus"

Antimicrobial peptides from echinoderms as antibiofilm agents: a natural strategy to combat bacterial infections

2014

AbstractIncreased attention has been focused on marine invertebrates as a source of bioactive molecules for biomedical applications. Many bioactive molecules are part of the innate immune system. Some more recently isolated compounds, mainly from the sea urchin and the sea cucumber, are antimicrobial peptides (AMPs) active against Gram-positive and Gram-negative bacteria, and fungi. In this review we described the most recent studies on AMPs isolated from echinoderms. AMPs are small peptides (< 10 kDa) with cationic charge and amphipathic structure. Recently, it was demonstrated that in the coelomocyte lysates of Paracentrotus lividus and Holothuria tubulosa, AMPs possess activity against s…

A member of the Tlr family is involved in dsRNA innate immune response in Paracentrotus lividus sea urchin

2015

Abstract The innate immune response involves proteins such as the membrane receptors of the Toll-like family (TLRs), which trigger different intracellular signalling pathways that are dependent on specific stimulating molecules. In sea urchins, TLR proteins are encoded by members of a large multigenic family composed of 60–250 genes in different species. Here, we report a newly identified mRNA sequence encoding a TLR protein (referred to as Pl-Tlr) isolated from Paracentrotus lividus immune cells. The partial protein sequence contained the conserved Toll/IL-1 receptor (TIR) domain, the transmembrane domain and part of the leucine repeats. Phylogenetic analysis of the Pl-Tlr protein was acco…

Centrifugation does not alter spatial distribution of `BEP4' mRNA in paracentrotus lividus EGG

1997

AbstractParacentrotus lividus unfertilized eggs were centrifuged in a sucrose gradient, so to split each into two parts: a nucleated light fragment and an anucleated heavy fragment. Northern blot analyses utilizing a bep4 probe as animal marker and H2A histone gene and 12S-mit RNA as controls indicate that the eggs are elongated along the animal-vegetal axis during centrifugation and thereafter split into an animal and a vegetal half. Treatment of the eggs with colchicine before centrifugation abolishes the animal localization of bep4 mRNA.

Manganese overload affects p38 MAPK phosphorylation and metalloproteinase activity during sea urchin embryonic development.

2014

Abstract In the marine environment, manganese represents a potential emerging contaminant, resulting from an increased production of manganese-containing compounds. In earlier reports we found that the exposure of Paracentrotus lividus sea urchin embryos to manganese produced phenotypes with no skeleton. In addition, manganese interfered with calcium uptake, perturbed extracellular signal-regulated kinase (ERK) signaling, affected the expression of skeletogenic genes, and caused an increase of the hsc70 and hsc60 protein levels. Here, we extended our studies focusing on the temporal activation of the p38 mitogen-activated protein kinase (p38 MAPK) and the proteolytic activity of metalloprot…

Characterization of three different clusters of 18S-26S ribosomal DNA genes in the sea urchin P. lividus: Genetic and epigenetic regulation synchrono…

2015

We previously reported the characterization 5S ribosomal DNA (rDNA) clusters in the common sea urchin Paracentrotus lividus and demonstrated the presence of DNA methylation-dependent silencing of embryo specific 5S rDNA cluster in adult tissue. In this work, we show genetic and epigenetic characterization of 18S-26S rDNA clusters in this specie. The results indicate the presence of three different 18S-26S rDNA clusters with different Non-Transcribed Spacer (NTS) regions that have different chromosomal localizations. Moreover, we show that the two largest clusters are hyper-methylated in the promoter-containing NTS regions in adult tissues, as in the 5S rDNA. These findings demonstrate an an…

Identification and characterization of PlAlix, the Alix homologue from the Mediterranean sea urchin Paracentrotus lividus.

2013

The sea urchin provides a relatively simple and tractable system for analyzing the early stages of embryo development. Here, we use the sea urchin species, Paracentrotus lividus, to investigate the role of Alix in key stages of embryogenesis, namely the egg fertilization and the first cleavage division. Alix is a multifunctional protein involved in different cellular processes including endocytic membrane trafficking, filamentous (F)-actin remodeling, and cytokinesis. Alix homologues have been identified in different metazoans; in these organisms, Alix is involved in oogenesis and in determination/differentiation events during embryo development. Herein, we describe the identification of th…

La raccolta del riccio di mare Paracentrotus lividus

2008

Allozyme Similarity in Two Morphologically Distinguishable Populations ofParacentrotus Lividus(Echinodermata) From Distinct Areas of the Mediterranea…

1998

Allozymes ofParacentrotus lividusfrom Palermo Gulf in the northern Sicilian coast (Italy) and from a small body-size population in the western Greek coast (Ionian Sea) were investigated by PAGE. Five of the twenty examined loci were polymorphic(AAT*, ADH*, ME*, PGI*andPGM*)over each population with a polymorphism value of 0–25. Average heterozygosity was equal to 0081 in the Sicilian sample and 0084 in the Greek. Deviations from Hardy-Weinberg equilibrium were significant inME*andPGI*loci (as calculated byy).Nei's (1978) genetic distance (D=0–0025) index described a close identity between the two samples. FSTvalue of polymorphic loci ranged from 0001 to 0029, its mean value (0–008) resultin…

Macroalgal assemblage type affects predation pressure on sea urchins by altering adhesion strength.

2010

In the Mediterranean, sea breams are the most effective Paracentrotus lividus and Arbacia lixula predators. Generally, seabreams dislodge adult urchins from the rocky substrate, turn them upside down and crush their tests. Sea urchins may respond to fish attacks clinging tenaciously to the substratum. This study is the first attempt to investigate sea urchin adhesion strength in two alternative algal assemblages of the rocky infralittoral and valuated its possible implication for fish predation. We hypothesized that (1) sea urchin adhesion strength is higher in rocky shores dominated by encrusting macro-algae (ECA) than in erected macro algae (EMA); (2) predation rates upon sea urchins are …

Hydrodynamism and its influence on the reproductive condition of the edible sea urchin Paracentrotus lividus

2013

Despite the large body of work published in the last two decades on the reproduction of the sea urchin Paracentrotus lividus, the reproductive aspects linked to hydrodynamic conditions and their influence on gonad production remain poorly understood. The present paper aims to evaluate the effect of hydrodynamism on the reproductive cycle of P. lividus. Variability in the gonadosomatic index (GSI) of P. lividus was estimated seasonally from 2007 to 2008 at two shallow sub-littoral flat basaltic areas at Ustica Island (Western Mediterranean). GSI was higher in the sites characterized by low hydrodynamism than in those with high hydrodynamism. Results also suggest a possible role for hydrodyna…