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| Clerissi, Camille; De Lorgeril, Julien; Petton, Bruno; Lucasson, Aude; Escoubas, Jean Michel; Gueguen, Yannick; Dégremont, Lionel; Mitta, Guillaume; Toulza, Eve. |
| Pacific Oyster Mortality Syndrome (POMS) affects Crassostrea gigas oysters worldwide and causes important economic losses. Disease dynamic was recently deciphered and revealed a multiple and progressive infection caused by the Ostreid herpesvirus OsHV-1 μVar, triggering an immunosuppression followed by microbiota destabilization and bacteraemia by opportunistic bacterial pathogens. However, it remains unknown if microbiota might participate to protect oysters against POMS, and if microbiota characteristics might be predictive of oyster mortalities. To tackle this issue, we transferred full-sib progenies of resistant and susceptible oyster families from hatchery to the field during a period in favor of POMS. After 5 days of transplantation, oysters from... |
| Tipo: Text |
Palavras-chave: Holobiont; Microbiome; Metabarcoding; Fitness; Bacteria. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00621/73332/72500.pdf |
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| Picot, Sandy; Morga, Benjamin; Faury, Nicole; Chollet, Bruno; Dégremont, Lionel; Travers, Marie-agnes; Renault, Tristan; Arzul, Isabelle. |
| Macroautophagy is a mechanism that is involved in various cellular processes, including cellular homeostasis and innate immunity. This pathway has been described in organisms ranging in complexity from yeasts to mammals, and recent results indicate that it occurs in the mantle of the Pacific oyster, Crassostrea gigas. However, the autophagy pathway has never been explored in the hemocytes of C. gigas, which are the main effectors of its immune system and thus play a key role in the defence of the Pacific oyster against pathogens. To investigate autophagy in oyster hemocytes, tools currently used to monitor this mechanism in mammals, including flow cytometry, fluorescent microscopy and transmission electron microscopy, were adapted and applied to the... |
| Tipo: Text |
Palavras-chave: Autophagosome; Autophagy; Crassostrea gigas; Flow cytometry; Fluorescence microscopy; Hemocytes; Transmission electron microscopy. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00487/59905/63087.pdf |
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| Dégremont, Lionel; Morga, Benjamin; Trancart, Suzanne; Pépin, Jean-francois. |
| The ostreid herpesvirus(OsHV-1) is one of the major diseases that affect the Pacific oyster Crassostrea gigas. Selective breeding programs were recently shown to improve resistance easily to OsHV-1 infections in spat, juvenile, and adult oysters. Nevertheless, this resistance has never been investigated in larvae, whereas this developmental stage has crucial importance for the production of commercial hatcheries, as well as explaining the abundance of spatfall. A first trial tested several viral suspensions at several concentrations using contaminated water with OsHV-1 in 4- and 10-day-old larvae that we reproduced from an unselected broodstock. In follow up on the results, one viral suspension at a final concentration of 10+6 OsHV-1 DNA copies per L was... |
| Tipo: Text |
Palavras-chave: Larvae; Crassostrea gigas; OsHV-1; Disease resistance; Mortality. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00313/42441/41796.pdf |
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| Divilov, Konstantin; Schoolfield, Blaine; Morga, Benjamin; Dégremont, Lionel; Burge, Colleen A.; Mancilla Cortez, Daniel; Friedman, Carolyn S.; Fleener, Gary B.; Dumbauld, Brett R.; Langdon, Chris. |
| Background Variants of the Ostreid herpesvirus 1 (OsHV-1) cause high losses of Pacific oysters globally, including in Tomales Bay, California, USA. A suite of new variants, the OsHV-1 microvariants (μvars), cause very high mortalities of Pacific oysters in major oyster-growing regions outside of the United States. There are currently no known Pacific oysters in the United States that are resistant to OsHV-1 as resistance has yet to be evaluated in these oysters. As part of an effort to begin genetic selection for resistance to OsHV-1, 71 families from the Molluscan Broodstock Program, a US West Coast Pacific oyster breeding program, were screened for survival after exposure to OsHV-1 in Tomales Bay. They were also tested in a quarantine laboratory in... |
| Tipo: Text |
Palavras-chave: Ostreid herpesvirus 1; Crassostrea gigas; Heritability; Breeding. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00598/70974/69206.pdf |
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| Dégremont, Lionel; Maurouard, Elise; Ledu, Christophe; Benabdelmouna, Abdellah. |
| Due to massive mortality of Crassostrea gigas spat in France since 2008, a “plan de sauvegarde” was set up from 2011 to 2014 (hereafter referred to as PS1 to PS4), in order to reduce the shortage of spat. This plan involved the participation of commercial hatcheries, the French Research Institute for Exploitation of the Sea (Ifremer), and the Direction des Pêches Maritimes et de l'Aquaculture (DPMA) of the French Ministry of Agriculture. It was based on selecting diploid lines of C. gigas for their higher resistance to the oyster herpesvirus OsHV-1 (2nR group), and one of these lines was subsequently tetraploidized (4nR group). Both the 2nR and 4nR groups were produced by Ifremer, and then transferred to commercial hatcheries that produced the selected... |
| Tipo: Text |
Palavras-chave: Triploids; Mortality; Crassostrea gigas; OsHV-1; Disease resistance. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00484/59596/62598.pdf |
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| Garcia, Celine; Mesnil, Aurelie; Tourbiez, Delphine; Moussa Pouly, Mirna; Dubreuil, Christine; Gonçalves De Sa, Amélie; Chollet, Bruno; Godfrin, Yoann; Dégremont, Lionel; Serpin, Delphine; Travers, Marie-agnes. |
| Cockle mortality events have been reported in northern France since 2012. In the present study, we describe and investigate the implication of a potential bacterial causative agent in cockle mortality. Bacteria isolated from five different cockle mortality events were characterized and studied. Using phenotypic analysis combined with DNA–DNA hybridization (DDH) and whole genome sequencing, the isolates were shown to belong to Vibrio aestuarianus , a species regularly detected in France during oyster mortality events. Comparison of the strains from cockles with strains from French oysters and the type strain showed that the strains from cockles were genetically different to those from oysters and also different to the V. aestuarianus type strain. Moreover,... |
| Tipo: Text |
Palavras-chave: Bacterial pathogen; Bivalvia; Cockle; Mortality; Shellfish; Vibrio aestuarianus. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78893/81195.pdf |
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| Broquard, Coralie; Martinez, Anne-sophie; Maurouard, Elise; Lamy, Jean-baptiste; Dégremont, Lionel. |
| Understanding sex determination in the Pacific oyster Crassostrea gigas, a sequential hermaphrodite, can provide prospective on the evolution of sex-determining systems for comparative reproduction from an evolutionary perspective. Surprisingly, this mechanism is still poorly understood. To date, sex ratio and sex change have never been studied at the individual level for a large size group and long-term monitoring. To this purpose, we performed an ambitious individual long-term follow-up (6 years) on a large population (cohort 1: 7488 oysters) produced from wild oysters, as well as for a second population produced from the cohort 1 (cohort 2: 4320 oysters). All oysters were individually sexed from 2014 to 2019. For the cohort 1, our results showed a... |
| Tipo: Text |
Palavras-chave: Sex-ratio; Sex change; Oysters; Hermaphroditism; Crassostrea gigas. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00587/69868/67845.pdf |
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