Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis
In France, oyster sites in the Mediterranean Sea are regularly confronted to high mortalities of Crassostrea gigas juveniles and to recurrent blooms of the dinoflagellate producer of Paralytic Shellfish Toxins (PSTs), Alexandrium catenella. Among the pathogens associated to these mortalities, we fou...
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Online Access: | https://theses.hal.science/tel-01450626 https://theses.hal.science/tel-01450626/document https://theses.hal.science/tel-01450626/file/Abi%20Khalil-2016.pdf |
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ftunivnantes:oai:HAL:tel-01450626v1 2023-05-15T15:57:39+02:00 Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis Effets apoptotiques du dinoflagellé Alexandrium catenella et de ses toxines sur les cellules immunitaires de l'huître creuse Crassostrea gigas. Implications dans la susceptibilité de l'huître aux vibrioses Abi-Khalil, Célina Interactions Hôtes-Pathogènes-Environnements (IHPE) Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM) Université de Montpellier Mohamed Laabir Jean Luc Rolland 2016-11-15 https://theses.hal.science/tel-01450626 https://theses.hal.science/tel-01450626/document https://theses.hal.science/tel-01450626/file/Abi%20Khalil-2016.pdf fr fre HAL CCSD tel-01450626 https://theses.hal.science/tel-01450626 https://theses.hal.science/tel-01450626/document https://theses.hal.science/tel-01450626/file/Abi%20Khalil-2016.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01450626 Evolution [q-bio.PE]. Université de Montpellier, 2016. Français. ⟨NNT : ⟩ Crassostrea gigas Alexandrium catenella Toxins Apoptosis Immune Cells vibriosis Toxines Apoptose Cellules immunitaires vibrioses [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE] info:eu-repo/semantics/doctoralThesis Theses 2016 ftunivnantes 2022-12-07T02:25:29Z In France, oyster sites in the Mediterranean Sea are regularly confronted to high mortalities of Crassostrea gigas juveniles and to recurrent blooms of the dinoflagellate producer of Paralytic Shellfish Toxins (PSTs), Alexandrium catenella. Among the pathogens associated to these mortalities, we found Vibrio strains belonging to Splendidus clade. We here focus on theinteractions between A. catenella and the oyster C. gigas challenged with pathogenic vibrios. In the first part of this work, we have shown that, in vivo, A. catenella increased the susceptibility of the oyster C. gigas to the pathogen Vibrio tasmaniensis LGP32. In situ, we also established the coincidence between oyster mortality in 2014 and the presence of PSTs in their tissues. In the second part of this work, we studied the interactions between the PSTs produced by A. catenella and oyster immune cells, the hemocytes. An important result of this thesis was that saxitoxin, a toxin produced by A. catenella, binds to granular structures in the cytoplasm of C. gigas hemocytes and induces their caspase-dependent cell death. This death is independent of the production of reactive oxygen species. We also demonstrated that the major toxin of A. catenella cells, the gonyautoxin 5, is the most toxic on C. gigas hemocytes. Among affected hemocyte populations, the hyalinocytes are very sensitive to this toxic stress. As hemocytes are oyster immunocompetent cells and therefore play the central role in the defense against infections, we can presume that their cell death induced by the PSTs negatively affects the defense of bivalve mollusks and explains the increased susceptibility of oysters to the infection by Vibrio tasmaniensis LGP32 when exposed to A. catenella. En France, les sites ostréicoles de la méditerranée sont confrontés régulièrement à de fortes mortalités de juvéniles de Crassostrea gigas mais également à des efflorescences récurrentes du dinoflagellé producteur de toxines paralysantes (PSTs), Alexandrium catenella. Parmi les pathogènes associés ... Doctoral or Postdoctoral Thesis Crassostrea gigas Université de Nantes: HAL-UNIV-NANTES |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Crassostrea gigas Alexandrium catenella Toxins Apoptosis Immune Cells vibriosis Toxines Apoptose Cellules immunitaires vibrioses [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE] |
spellingShingle |
Crassostrea gigas Alexandrium catenella Toxins Apoptosis Immune Cells vibriosis Toxines Apoptose Cellules immunitaires vibrioses [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE] Abi-Khalil, Célina Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
topic_facet |
Crassostrea gigas Alexandrium catenella Toxins Apoptosis Immune Cells vibriosis Toxines Apoptose Cellules immunitaires vibrioses [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE] |
description |
In France, oyster sites in the Mediterranean Sea are regularly confronted to high mortalities of Crassostrea gigas juveniles and to recurrent blooms of the dinoflagellate producer of Paralytic Shellfish Toxins (PSTs), Alexandrium catenella. Among the pathogens associated to these mortalities, we found Vibrio strains belonging to Splendidus clade. We here focus on theinteractions between A. catenella and the oyster C. gigas challenged with pathogenic vibrios. In the first part of this work, we have shown that, in vivo, A. catenella increased the susceptibility of the oyster C. gigas to the pathogen Vibrio tasmaniensis LGP32. In situ, we also established the coincidence between oyster mortality in 2014 and the presence of PSTs in their tissues. In the second part of this work, we studied the interactions between the PSTs produced by A. catenella and oyster immune cells, the hemocytes. An important result of this thesis was that saxitoxin, a toxin produced by A. catenella, binds to granular structures in the cytoplasm of C. gigas hemocytes and induces their caspase-dependent cell death. This death is independent of the production of reactive oxygen species. We also demonstrated that the major toxin of A. catenella cells, the gonyautoxin 5, is the most toxic on C. gigas hemocytes. Among affected hemocyte populations, the hyalinocytes are very sensitive to this toxic stress. As hemocytes are oyster immunocompetent cells and therefore play the central role in the defense against infections, we can presume that their cell death induced by the PSTs negatively affects the defense of bivalve mollusks and explains the increased susceptibility of oysters to the infection by Vibrio tasmaniensis LGP32 when exposed to A. catenella. En France, les sites ostréicoles de la méditerranée sont confrontés régulièrement à de fortes mortalités de juvéniles de Crassostrea gigas mais également à des efflorescences récurrentes du dinoflagellé producteur de toxines paralysantes (PSTs), Alexandrium catenella. Parmi les pathogènes associés ... |
author2 |
Interactions Hôtes-Pathogènes-Environnements (IHPE) Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM) Université de Montpellier Mohamed Laabir Jean Luc Rolland |
format |
Doctoral or Postdoctoral Thesis |
author |
Abi-Khalil, Célina |
author_facet |
Abi-Khalil, Célina |
author_sort |
Abi-Khalil, Célina |
title |
Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
title_short |
Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
title_full |
Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
title_fullStr |
Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
title_full_unstemmed |
Apoptotic effects of dinoflagella Alexandrium catenella and its toxins on immune cells of hollow oyster Crassostrea gigas. Implications in the susceptibility of the oyster to vibriosis |
title_sort |
apoptotic effects of dinoflagella alexandrium catenella and its toxins on immune cells of hollow oyster crassostrea gigas. implications in the susceptibility of the oyster to vibriosis |
publisher |
HAL CCSD |
publishDate |
2016 |
url |
https://theses.hal.science/tel-01450626 https://theses.hal.science/tel-01450626/document https://theses.hal.science/tel-01450626/file/Abi%20Khalil-2016.pdf |
genre |
Crassostrea gigas |
genre_facet |
Crassostrea gigas |
op_source |
https://theses.hal.science/tel-01450626 Evolution [q-bio.PE]. Université de Montpellier, 2016. Français. ⟨NNT : ⟩ |
op_relation |
tel-01450626 https://theses.hal.science/tel-01450626 https://theses.hal.science/tel-01450626/document https://theses.hal.science/tel-01450626/file/Abi%20Khalil-2016.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766393319798079488 |