Search results for "Paracentrotus"

Stato e conservazione di Paracentrotus lividus nell’ AMP Plemmirio.

2011

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…

ANTIMICROBIAL AND ANTISTAPHYLOCOCCAL BIOFILM ACTIVITY FROM THE SEA URCHIN PARACENTROTUS LIVIDUS

2009

Aims: Staphylococcal biofilm-associated infections are resistant to conventional antibiotics. Consequently, new agents are needed to treat them. With this aim, we focused on the effector cells (coelomocytes) of the sea urchin Paracentrotus lividus immune system. Methods and Results: We tested the activity of the 5-kDa peptide fraction of the cytosol from coelomocytes (5-CC) against a group of Gram-positive, Gram-negative bacteria and fungi. We determined minimal inhibitory concentrations (MICs) ranging from 253.7 to 15.8 mg ml(-1). We observed an inhibitory activity and antibiofilm properties of 5-CC against staphylococcal biofilms of reference strains Staphylococcus epidermidis DSM 3269 an…

Strategie di difesa in risposta a stress in embrioni di riccio di mare: L'embrione di riccio di Paracentrotus lividus come modello sperimentale per l…

2013

Negli ultimi decenni, grazie alle nuove tecnologie e alla maggiore disponibilità di strumenti di ricerca, il campo riguardante lo studio delle strategie di difesa attivate nella risposta a stress, compresi i meccanismi di apoptosi e autofagia, è divenuto molto ampio ed è in continua espansione. Sin dagli albori della Biologia, gli studi condotti sul modello sperimentale di riccio di mare hanno permesso di ottenere conoscenze di base, spesso applicabili ad altri modelli biologici. I dati riportati nel presente libro dovrebbero aiutare a far luce sui meccanismi di difesa che le cellule sono in grado di attivare, in caso di necessità, se esposte a sfavorevoli condizioni ambientali. Le osservaz…

Studies on sea urchin oocytes. II. Synthesis of RNA during oogenesis.

1972

Abstract Isolated oocytes of the sea urchin Paracentrotus lividus actively incorporate 3H-uridine into RNA. Labeled RNA was analysed by sucrose gradient and acrylamide gel electrophoresis following cell fractionation. Much of the radioactivity is incorporated at the nucleolar level in the form of rRNA precursors. The kinetics of maturation of these latter suggests that this occurs at a slower rate than during embryogenesis. Other non-nucleolar RNA classes are also actively labelled and retained in the nucleus for many hours. These results are confirmed by an autoradiographic investigation.

Ectoderm restricted expression of the TRIM-containing factor Strim1 directs the migration, aggregation and terminal differentiation of mesenchymal ce…

2011

Constitutive hsp70 is essential to mitosis during early cleavage of Paracentrotus lividus embryos: The blockage of constitutive hsp70 impairs mitosis

1999

Localization of constitutive hsp70 in eggs and early embryos of sea urchin Paracentrotus lividus is shown by means of in situ immunostaining. An accumulation of this protein is shown in the mitotic structures (asters, spindles and centrosomes). Microinjection of anti-hsp70 antibodies into eggs causes impairment of formation of mitotic structures and of cell division. This impairment goes from a complete mitotic block, to irregular mitotic apparatus formation with irregular cleavage, depending upon the antibody concentration. The localization of hsp70 after antibody microinjection is also described. Blockage of mitotic apparatus formation by nocodazole also blocks the concentration of hsp70 …

Promoter activity of the sea urchin (Paracentrotus lividus) nucleosomal H3 and H2A and linker H1 a-histone genes is modulated by enhancer and chromat…

2009

Core promoters and chromatin insulators are key regulatory elements that may direct a transcriptional enhancer to prefer a specific promoter in complex genetic loci. Enhancer and insulator flank the sea urchin (Paracentrotus lividus) alpha-histone H2A transcription unit in a tandem repeated cluster containing the five histone genes. This article deals with the specificity of interaction between the H2A enhancer-bound MBF-1 activator and histone gene promoters, and with the mechanism that leads the H1 transcripts to peak at about one-third of the value for nucleosomal H3 and H2A mRNAs. To this end, in vivo competition assays of enhancer and insulator functions were performed. Our evidence su…

Sea urchin neural alpha 2 tubulin gene: isolation and promoter analysis

2004

Abstract Expression of Tα2 gene, during sea urchin Paracentrotus lividus development, is spatially and temporally regulated. In order to characterize this gene, we isolated the relevant genomic sequences and scanned the isolated 5 ′ -flanking region in searching for cis -regulatory elements required for proper expression. Gel mobility shift and footprinting assays, as well as reporter gene (CAT and β-gal) expression assays, were used to address cis -regulatory elements involved in regulation. Here we report that an upstream 5 ′ -flanking fragment of PlTα2 gene drives temporal expression of reporter genes congruent with that of endogenous Tα2 gene. The fragment contains cis -elements able to…

Aberrant gene expression profiles in Mediterranean sea urchin reproductive tissues after metal exposures

2019

Abstract Marine organisms are simultaneously exposed to numerous pollutants, among which metals probably represent the most abundant in marine environments. In order to evaluate the effects of metal exposure at molecular level in reproductive tissues, we profiled the sea urchin transcriptional response after non-lethal exposures using pathway-focused mRNA expression analyses. Herein, we show that exposures to relatively high concentrations of both essential and toxic metals hugely affected the gonadic expression of several genes involved in stress-response, detoxification, transcriptional and post-transcriptional regulation, without significant changes in gonadosomatic indices. Even though …