A Feedback Mechanism to Control Apoptosis Occurs in the Digestive Gland of the Oyster Crassostrea gigas Exposed to the Paralytic Shellfish Toxins Producer Alexandrium catenella
Jean-Luc Rolland,
Walid Medhioub,
Agnes Vergnes,
Celina Abi-khalil,
Véronique Savar,
Eric Abadie,
Estelle Masseret,
Zouher Amzil,
Mohamed Laabir
Affiliations
Jean-Luc Rolland
IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, Montpellier cedex 5 34095, France
Walid Medhioub
INSTM, Institut National des Sciences et Technologies de la Mer, Laboratoire d'Aquaculture, 28 rue du 2 mars 1934, Salammbô 2025, Tunisia
Agnes Vergnes
IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, Montpellier cedex 5 34095, France
Celina Abi-khalil
IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, Montpellier cedex 5 34095, France
Véronique Savar
IFREMER, Laboratoire Phycotoxines (PHYC), Rue de l'Ile d'Yeu BP 21105, Nantes Cedex 3 44311, France
Eric Abadie
IFREMER, Département des laboratoires côtiers Environnement littoral et Ressources aquacoles (LER-LR), Avenue Jean Monnet, BP 171, Sète Cedex 34203, France
Estelle Masseret
IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, Montpellier cedex 5 34095, France
Zouher Amzil
IFREMER, Laboratoire Phycotoxines (PHYC), Rue de l'Ile d'Yeu BP 21105, Nantes Cedex 3 44311, France
Mohamed Laabir
IFREMER, Université Montpellier 2, Centre National de la Recherche Scientifique, IRD, UM1, UMR 5119 "Ecologie des Systèmes Marins Côtiers", Place E. Bataillon, CC93, Montpellier cedex 5 34095, France
To better understand the effect of Paralytic Shellfish Toxins (PSTs) accumulation in the digestive gland of the Pacific oyster, Crassostrea gigas, we experimentally exposed individual oysters for 48 h to a PSTs producer, the dinoflagellate Alexandrium catenella. In comparison to the effect of the non-toxic Alexandrium tamarense, on the eight apoptotic related genes tested, Bax and BI.1 were significantly upregulated in oysters exposed 48 h to A. catenella. Among the five detoxification related genes tested, the expression of cytochrome P450 (CYP1A) was shown to be correlated with toxin concentration in the digestive gland of oysters exposed to the toxic dinoflagellate. Beside this, we observed a significant increase in ROS production, a decrease in caspase-3/7 activity and normal percentage of apoptotic cells in this tissue. Taken together, these results suggest a feedback mechanism, which may occur in the digestive gland where BI.1 could play a key role in preventing the induction of apoptosis by PSTs. Moreover, the expression of CYP1A, Bax and BI.1 were found to be significantly correlated to the occurrence of natural toxic events, suggesting that the expression of these genes together could be used as biomarker to assess the biological responses of oysters to stress caused by PSTs.
