Publications by authors named "Santini Adrien"

5 Publications

  • Page 1 of 1

Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers.

Mar Pollut Bull 2017 May 18;118(1-2):420-426. Epub 2017 Mar 18.

Ifremer, UMR 241 EIO, UPF-ILM-IRD, Labex Corail, BP 49, 98719 Taravao, Tahiti, French Polynesia. Electronic address:

This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10μgL) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
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http://dx.doi.org/10.1016/j.marpolbul.2017.03.012DOI Listing
May 2017

High polymorphism in big defensin gene expression reveals presence-absence gene variability (PAV) in the oyster Crassostrea gigas.

Dev Comp Immunol 2015 Apr 4;49(2):231-8. Epub 2014 Dec 4.

Ifremer, CNRS, Université Montpellier 2, IRD, Université Montpellier 1, UMR5119 - Ecology of Coastal Marine Systems, Place Eugène Bataillon, CC80, 34095 Montpellier, France.

We report here the first evidence in an invertebrate, the oyster Crassostrea gigas, of a phenomenon of Presence-Absence Variation (PAV) affecting immune-related genes. We previously evidenced an extraordinary interindividual variability in the basal mRNA abundances of oyster immune genes including those coding for a family of antimicrobial peptides, the big defensins (Cg-BigDef). Cg-BigDef is a diverse family composed of three members: Cg-BigDef1 to -3. Here, we show that besides a high polymorphism in Cg-BigDef mRNA expression, not all individual oysters express simultaneously the three Cg-BigDefs. Moreover, in numerous individuals, no expression of Cg-BigDefs could be detected. Further investigation at the genomic level revealed that in individuals in which the transcription of one or all Cg-BigDefs was absent the corresponding Cg-bigdef gene was missing. In our experiments, no correlation was found between Cg-bigdef PAV and oyster capacity to survive Vibrio infections. The discovery of P-A immune genes in oysters leads to reconsider the role that the immune system plays in the individual adaptation to survive environmental, biotic and abiotic stresses.
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http://dx.doi.org/10.1016/j.dci.2014.12.002DOI Listing
April 2015

Sequence polymorphism and expression variability of Crassostrea gigas immune related genes discriminate two oyster lines contrasted in term of resistance to summer mortalities.

PLoS One 2013 26;8(9):e75900. Epub 2013 Sep 26.

Institut Français de Recherche pour l'Exploitation de la Mer, Centre National de la Recherche Scientifique, Université de Montpellier 2, Université de Montpellier 1, Institut de la Recherche pour le Développement, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Montpellier, France.

Summer mortalities of Crassostreagigas are a major concern in oyster aquaculture. They are the result of a complex interaction between the host, pathogens and environmental factors. Oyster genetics have been identified as an essential determinant of oyster susceptibility to summer mortalities. As the capability of oysters to circumvent diseases depends in part on their immune defenses, we aimed to analyze the gene expression and sequence polymorphism of 42 immune related genes in two oyster lines selected for their "High" (H) and "Low" (L) survival to summer mortalities. Results showed that the variability of gene expression and the sequence polymorphism acting on particular genes could enable the discrimination between H and L oyster lines. Besides, a higher sequence polymorphism was observed on the L line affecting 11 of the 42 analyzed genes. By analyzing gene expression, sequence polymorphism and gene copy number of two antimicrobial peptide families (Cg-Defs and Cg-Prp), and an antimicrobial protein (Cg-BPI) on individual oysters, we showed that gene expression and/or sequence polymorphism could also discriminate H and L oyster lines. Finally, we observed a positive correlation between the gene expression and the gene copy number of antimicrobials and that sequence polymorphism could be encoded in the genome. Overall, this study gives new insights in the relationship between oyster immunity and divergent phenotypes, and discusses the potential implication of antimicrobial diversity in oyster survival to summer mortalities.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0075900PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3784401PMC
July 2014

Paralytic toxins accumulation and tissue expression of α-amylase and lipase genes in the Pacific oyster Crassostrea gigas fed with the neurotoxic dinoflagellate Alexandrium catenella.

Mar Drugs 2012 Nov 12;10(11):2519-34. Epub 2012 Nov 12.

IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, 34095 Montpellier Cedex 5, France.

The pacific oyster Crassostrea gigas was experimentally exposed to the neurotoxic Alexandrium catenella and a non-producer of PSTs, Alexandrium tamarense (control algae), at concentrations corresponding to those observed during the blooming period. At fixed time intervals, from 0 to 48 h, we determined the clearance rate, the total filtered cells, the composition of the fecal ribbons, the profile of the PSP toxins and the variation of the expression of two α-amylase and triacylglecerol lipase precursor (TLP) genes through semi-quantitative RT-PCR. The results showed a significant decrease of the clearance rate of C. gigas fed with both Alexandrium species. However, from 29 to 48 h, the clearance rate and cell filtration activity increased only in oysters fed with A. tamarense. The toxin concentrations in the digestive gland rose above the sanitary threshold in less than 48 h of exposure and GTX6, a compound absent in A. catenella cells, accumulated. The α-amylase B gene expression level increased significantly in the time interval from 6 to 48 h in the digestive gland of oysters fed with A. tamarense, whereas the TLP gene transcript was significantly up-regulated in the digestive gland of oysters fed with the neurotoxic A. catenella. All together, these results suggest that the digestion capacity could be affected by PSP toxins.
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http://dx.doi.org/10.3390/md10112519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509533PMC
November 2012

Big defensins, a diverse family of antimicrobial peptides that follows different patterns of expression in hemocytes of the oyster Crassostrea gigas.

PLoS One 2011 28;6(9):e25594. Epub 2011 Sep 28.

IFREMER, CNRS, Université Montpellier 2, IRD, and Université Montpellier 1, UMR 5119 "Écologie des Systèmes Marins Côtiers", Montpellier, France.

Background: Big defensin is an antimicrobial peptide composed of a highly hydrophobic N-terminal region and a cationic C-terminal region containing six cysteine residues involved in three internal disulfide bridges. While big defensin sequences have been reported in various mollusk species, few studies have been devoted to their sequence diversity, gene organization and their expression in response to microbial infections.

Findings: Using the high-throughput Digital Gene Expression approach, we have identified in Crassostrea gigas oysters several sequences coding for big defensins induced in response to a Vibrio infection. We showed that the oyster big defensin family is composed of three members (named Cg-BigDef1, Cg-BigDef2 and Cg-BigDef3) that are encoded by distinct genomic sequences. All Cg-BigDefs contain a hydrophobic N-terminal domain and a cationic C-terminal domain that resembles vertebrate β-defensins. Both domains are encoded by separate exons. We found that big defensins form a group predominantly present in mollusks and closer to vertebrate defensins than to invertebrate and fungi CSαβ-containing defensins. Moreover, we showed that Cg-BigDefs are expressed in oyster hemocytes only and follow different patterns of gene expression. While Cg-BigDef3 is non-regulated, both Cg-BigDef1 and Cg-BigDef2 transcripts are strongly induced in response to bacterial challenge. Induction was dependent on pathogen associated molecular patterns but not damage-dependent. The inducibility of Cg-BigDef1 was confirmed by HPLC and mass spectrometry, since ions with a molecular mass compatible with mature Cg-BigDef1 (10.7 kDa) were present in immune-challenged oysters only. From our biochemical data, native Cg-BigDef1 would result from the elimination of a prepropeptide sequence and the cyclization of the resulting N-terminal glutamine residue into a pyroglutamic acid.

Conclusions: We provide here the first report showing that big defensins form a family of antimicrobial peptides diverse not only in terms of sequences but also in terms of genomic organization and regulation of gene expression.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0025594PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182236PMC
January 2012