Publications by authors named "C Belliard"

12 Publications

Dual RNAseq highlights the kinetics of skin microbiome and fish host responsiveness to bacterial infection.

Anim Microbiome 2021 May 7;3(1):35. Epub 2021 May 7.

Ifremer, IRD, Institut Louis-Malardé, Univ Polynésie Française, EIO, F-98719 Taravao, Tahiti, Polynésie Française.

Background: Tenacibaculum maritimum is a fish pathogen known for causing serious damage to a broad range of wild and farmed marine fish populations worldwide. The recently sequenced genome of T. maritimum strain NCIMB 2154 provided unprecedented information on the possible molecular mechanisms involved in the virulence of this species. However, little is known about the dynamic of infection in vivo, and information is lacking on both the intrinsic host response (gene expression) and its associated microbiota. Here, we applied complementary omic approaches, including dual RNAseq and 16S rRNA gene metabarcoding sequencing using Nanopore and short-read Illumina technologies to unravel the host-pathogen interplay in an experimental infection system using the tropical fish Platax orbicularis as model.

Results: We showed that the infection of the host is characterised by an enhancement of functions associated with antibiotic and glucans catabolism functions but a reduction of sulfate assimilation process in T. maritimum. The fish host concurrently displays a large panel of immune effectors, notably involving innate response and triggering acute inflammatory response. In addition, our results suggest that fish activate an adaptive immune response visible through the stimulation of T-helper cells, Th17, with congruent reduction of Th2 and T-regulatory cells. Fish were, however, largely sensitive to infection, and less than 25% survived after 96 hpi. These surviving fish showed no evidence of stress (cortisol levels) or significant difference in microbiome diversity compared with controls at the same sampling time. The presence of T. maritimum in resistant fish skin and the total absence of any skin lesions suggest that these fish did not escape contact with the pathogen, but rather that some mechanisms prevented pathogens entry. In resistant individuals, we detected up-regulation of specific immune-related genes differentiating resistant individuals from controls at 96 hpi, which suggests a possible genomic basis of resistance, although no genetic variation in coding regions was found.

Conclusion: Here we focus in detail on the interplay between common fish pathogens and host immune response during experimental infection. We further highlight key actors of defence response, pathogenicity and possible genomic bases of fish resistance to T. maritimum.
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http://dx.doi.org/10.1186/s42523-021-00097-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8106148PMC
May 2021

Dynamic Energy Budget model suggests feeding constraints and physiological stress in black-lip pearl oysters, 5 years post mass-mortality event.

Mar Pollut Bull 2021 Jun 13;167:112329. Epub 2021 Apr 13.

IFREMER, IRD, Institut Louis-Malardé, Univ Polynésie française, EIO, F-98719 Taravao, Tahiti, French Polynesia.

Mass-mortality events of marine species can disturb the structure of communities. While identifying the causes of mass-mortality events is crucial for implementing recovery strategies, monitoring is challenging in remote locations. Black-lip pearl oysters (Pinctada margaritifera) are farmed for producing black pearls within remote atolls of French Polynesia. Previous mass-mortality events have resulted in the collapse of oysters and other species; however, the causes and conditions that favour recovery are unclear. We investigated the potential for oyster population recovery 5 years after a mortality event at Takaroa Atoll (Tuamotu Archipelago). Temperature, food availability (total chlorophyll-a), growth and reproduction were monitored. Growth was also simulated using a Dynamic Energy Budget model. Despite favourable conditions, reduced growth and reproduction signalled an energetic deficit. The model overpredicted growth, and supported the hypotheses that individuals are unable to profit from the phytoplankton available and maintenance costs are high in Takaroa, ultimately explaining their poor physiological condition.
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http://dx.doi.org/10.1016/j.marpolbul.2021.112329DOI Listing
June 2021

Household Food and Water Emergency Preparedness Practices Across the United States.

Disaster Med Public Health Prep 2021 Apr 6:1-9. Epub 2021 Apr 6.

Department of Nutrition, Dietetics, and Food Science, Brigham Young University, Provo, UT, USA.

Objective: To evaluate food and water storage practices in the United States, including the extent that government emergency preparedness guidelines were followed.

Methods: Qualtrics panelists (n = 572) completed a 142-item online survey in August 2014. Cognitive interviews (n = 5) and pilot data (n = 14) informed survey development. Descriptive statistics were used to analyze quantitative data. Open-ended responses related to water storage preparation were classified into 5 categories.

Results: Many respondents reported being somewhat or well prepared to provide food and water for their households during a large-scale disaster or emergency. Only 53% met Federal Emergency Management Agency (FEMA) guidelines to have water last at least 3 days. Based on respondents' self-report, it appeared that those who prepared personally-filled containers for water did not carefully follow FEMA instructions. Most respondents had non-perishable foods available, with 96% meeting the FEMA guidelines of at least 3 days of storage.

Conclusion: Households were generally prepared to provide food and, to a lesser extent, water in emergency situations, but were not consistently following FEMA guidelines. Additional easy-to-follow, evidence-based information may better help citizens accurately implement food and water storage emergency preparedness guidelines.
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http://dx.doi.org/10.1017/dmp.2020.480DOI Listing
April 2021

French Red Cross Ladies in International or Universal Exhibitions (1867-1937).

Front Sociol 2019 10;4:54. Epub 2019 Jul 10.

Sorbonne Nouvelle, Université Paris-Sorbonne, Paris, France.

This paper attempts to pinpoint what French Red-Cross women were doing in the international exhibitions from 1867 to 1937. They engaged their energies into organizing meetings, exhibitions, and into healing, receiving awards for their work. In spite of their dual activity of exhibitors and healthcarers, they had no specific pavilion at the world fairs. They hovered between the worlds of politics and medicine as distinguished guests but without their own space.
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http://dx.doi.org/10.3389/fsoc.2019.00054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8022656PMC
July 2019

Influence of temperature and pearl rotation on biomineralization in the pearl oyster, .

J Exp Biol 2018 09 21;221(Pt 18). Epub 2018 Sep 21.

Ifremer, UMR EIO 241, Labex Corail, Centre du Pacifique, BP 49, 98719 Taravao, Tahiti, French Polynesia.

The objective of this study was to observe the impact of temperature on pearl formation using an integrative approach describing the rotation of the pearls, the rate of nacre deposition, the thickness of the aragonite tablets and the biomineralizing potential of the pearl sac tissue though the expression level of some key genes. Fifty pearl oysters were grafted with magnetized nuclei to allow the rotation of the pearls to be described. Four months later, 32 of these pearl oysters were exposed to four temperatures (22, 26, 30 and 34°C) for 2 weeks. Results showed that the rotation speed differed according to the movement direction: pearls with axial movement had a significantly higher rotation speed than those with random movement. Pearl growth rate was influenced by temperature, with a maximum between 26 and 30°C but almost no growth at 34°C. Lastly, among the nine genes implicated in the biomineralization process, only expression was significantly modified by temperature. These results showed that the rotation speed of the pearls was not linked to pearl growth or to the expression profiles of biomineralizing genes targeted in this study. On the basis of our results, we consider that pearl rotation is a more complex process than formerly thought. Mechanisms involved could include a strong environmental forcing in immediate proximity to the pearl. Another implication of our findings is that, in the context of ocean warming, pearl growth and quality can be expected to decrease in pearl oysters exposed to temperatures above 30°C.
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http://dx.doi.org/10.1242/jeb.186858DOI Listing
September 2018