Defensome against Toxic Diatom Aldehydes in the Sea Urchin Paracentrotus lividus

Abstract

Many diatom species produce polyunsaturated aldehydes, such as decadienal, which compromise embryonic and larval development in benthic organisms. Here newly fertilized Paracentrotus lividus sea urchins were exposed to low concentration of decadienal and the expression levels of sixteen genes, implicated in a broad range of functional responses, were followed by Real Time qPCR in order to identify potential decadienal targets. We show that at low decadienal concentrations the sea urchin Paracentrotus lividus places in motion different classes of genes to defend itself against this toxic aldehyde, activating hsp60 and two proteases, hat and BP10, at the blastula stage and hsp56 and several other genes (14-3-3ε, p38 MAPK, MTase, and GS) at the prism stage. At this latter stage all genes involved in skeletogenesis (Nec, uni, SM50 and SM30) were also down-expressed, following developmental abnormalities that mainly affected skeleton morphogenesis. Moreover, sea urchin embryos treated with increasing concentrations of decadienal revealed a dose-dependent response of activated target genes. Finally, we suggest that this orchestrated defense system against decadienal represents part of the chemical defensome of P. lividus affording protection from environmental toxicants.

Molecular Response to Toxic Diatom-Derived Aldehydes in the Sea Urchin Paracentrotus lividus

“…More generally, the new genes analysed in this work can be considered as an additional part of the stress surveillance system or chemical defensome of the sea urchin, as proposed in Marrone et al [13], affording protection from environmental xenobiotics.…”

Diatom-derived oxylipins induce cell death in sea urchin embryos activating caspase-8 and caspase 3/7

“…The expression level of caspase-3/7 and caspase-8 (previously analysed in Marrone et al, 2012) genes was followed by Real Time qPCR. Since caspase-3 and caspase-7 gene sequences of P. lividus were not available, a sequence of a gene annotated as caspase 3/7 (Sp-Cspe3/7L, ID SPU 002280) in the sea urchin S. purpuratus was retrieved from SpBase (http://spbase.org/ , primary site for genomic information on the sea urchin S. purpuratus; Cameron et al, 2009).…”

“…lividus embryos were allowed to develop in the presence of PUAs and HEPEs at the concentrations producing about 35% of abnormal plutei at 48 hpf (Marrone et al, 2012;Varrella et al, 2014): decadienal 1.6 M, heptadienal 3.0 M, octadienal 4.5 M, 5-and 15-HEPE at 7 M. Embryos were collected at different development times after fertilization, corresponding to the stages of early blastula (5 hpf), swimming blastula (9 hpf), prism (24 hpf) and pluteus (48 hpf). The expression levels of caspase-8 and caspase3/7 genes were followed by Real Time qPCR (Figs.…”

“…At these lower concentrations decadienal was able to induce embryonic malformations in a concentration-dependent manner, whereas at higher concentrations embryos showed blebbing associated with apoptosis. More recently, molecular studies at low concentration have revealed that decadienal affected the expression levels of the caspase-8 gene in P. lividus embryos (Marrone et al, 2012).…”

Tissue-specificity and phylogenetics of Pl-MT mRNA during Paracentrotus lividus embryogenesis

“…In particular, new insights on MTs role have been gained from marine invertebrates, such as sponges, bivalves, crustaceans, and echinoderms (Capdevila and Atrian, 2011;Schroder et al, 2000;Tanguy and Moraga, 2001;Vergani et al, 2005). The increasing interest towards marine organisms comes mostly from monitoring programs, in which MTs are accounted as useful biomarkers for the assessment of environmental pollution (Canesi et al, 2010;Marrone et al, 2012;Sanchez and Porcher, 2009). For example, the induction of MT gene expression after exposure to Cd has been well documented in a variety of marine organisms including sponges (Schroder et al, 2000), bivalve mussels (Wang and Rainbow, 2010; and sea urchins (Russo et al, 2003;Filosto et al, 2008, for review see Amiard et al, 2006;Roccheri and Matranga, 2009).…”