Publications by authors named "Magre Kevin"

4 Publications

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A star is born again: Methods for larval rearing of an emerging model organism, the False clownfish Amphiprion ocellaris.

J Exp Zool B Mol Dev Evol 2021 Feb 4. Epub 2021 Feb 4.

CNRS, FR3724, Observatoire Océanologique, Sorbonne Université, Banyuls-sur-Mer, France.

As interest increases in ecological, evolutionary, and developmental biology (Eco-Evo-Devo), wild species are increasingly used as experimental models. However, we are still lacking a suitable model for marine fish species, as well as coral reef fishes that can be reared at laboratory scales. Extensive knowledge of the life cycle of anemonefishes, and the peculiarities of their biology, make them relevant marine fish models for developmental biology, ecology, and evolutionary sciences. Here, we present standard methods to maintain breeding pairs of the anemonefish Amphiprion ocellaris in captivity, obtain regular good quality spawning, and protocols to ensure larval survival throughout rearing. We provide a detailed description of the anemonefish husbandry system and life prey culturing protocols. Finally, a "low-volume" rearing protocol useful for the pharmacological treatment of larvae is presented. Such methods are important as strict requirements for large volumes in rearing tanks often inhibit continuous treatments with expensive or rare compounds.
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http://dx.doi.org/10.1002/jez.b.23028DOI Listing
February 2021

Sea anemone and clownfish microbiota diversity and variation during the initial steps of symbiosis.

Sci Rep 2019 12 20;9(1):19491. Epub 2019 Dec 20.

Observatoire Océanologique de Banyuls-sur-Mer, UMR CNRS 7232 BIOM; Sorbonne Université Paris; 1, avenue Pierre Fabre, 66650, Banyuls-sur-Mer, France.

Clownfishes and sea anemones form an intriguing long-term association, but the mechanism underlying this symbiosis is not well understood. Since clownfishes seem to cover themselves with sea anemone mucus, we investigated the microbiomes of the two partners to search for possible shifts in their compositions. We used a 16S rRNA gene sequencing strategy to study the dynamics of the microbiota during the association between the clownfish Amphiprion ocellaris and its host Heteractis magnifica under laboratory conditions. The experiment conducted in aquaria revealed that both clownfish and sea anemone mucus had specific signatures compared to artificial sea water. The microbiomes of both species were highly dynamic during the initiation of the symbiosis and for up to seven days after contact. Three families of bacteria (Haliangiaceae, Pseudoalteromonadacae, Saprospiracae) were shared between the two organisms after symbiosis. Once the symbiosis had been formed, the clownfishes and sea anemone then shared some communities of their mucus microbiota. This study paves the way for further investigations to determine if similar microbial signatures exist in natural environments, whether such microbial sharing can be beneficial for both organisms, and whether the microbiota is implicated in the mechanisms that protect the clownfish from sea anemone stinging.
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http://dx.doi.org/10.1038/s41598-019-55756-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6925283PMC
December 2019

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

Bacterial community characterization of water and intestine of the shrimp Litopenaeus stylirostris in a biofloc system.

BMC Microbiol 2016 07 19;16(1):157. Epub 2016 Jul 19.

Ifremer, UMR 241 EIO, UPF-ILM-IRD, Labex Corail, B.P. 7004, 98719, Taravao, Tahiti, French Polynesia.

Background: Biofloc technology (BFT), a rearing method with little or no water exchange, is gaining popularity in aquaculture. In the water column, such systems develop conglomerates of microbes, algae and protozoa, together with detritus and dead organic particles. The intensive microbial community presents in these systems can be used as a pond water quality treatment system, and the microbial protein can serve as a feed additive. The current problem with BFT is the difficulty of controlling its bacterial community composition for both optimal water quality and optimal shrimp health. The main objective of the present study was to investigate microbial diversity of samples obtained from different culture environments (Biofloc technology and clear seawater) as well as from the intestines of shrimp reared in both environments through high-throughput sequencing technology.

Results: Analyses of the bacterial community identified in water from BFT and "clear seawater" (CW) systems (control) containing the shrimp Litopenaeus stylirostris revealed large differences in the frequency distribution of operational taxonomic units (OTUs). Four out of the five most dominant bacterial communities were different in both culture methods. Bacteria found in great abundance in BFT have two principal characteristics: the need for an organic substrate or nitrogen sources to grow and the capacity to attach to surfaces and co-aggregate. A correlation was found between bacteria groups and physicochemical and biological parameters measured in rearing tanks. Moreover, rearing-water bacterial communities influenced the microbiota of shrimp. Indeed, the biofloc environment modified the shrimp intestine microbiota, as the low level (27 %) of similarity between intestinal bacterial communities from the two treatments.

Conclusion: This study provides the first information describing the complex biofloc microbial community, which can help to understand the environment-microbiota-host relationship in this rearing system.
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http://dx.doi.org/10.1186/s12866-016-0770-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4952143PMC
July 2016