Bonilla-Findji, O., Rochelle-Newall, E., Weinbauer, M. G., Pizay, M. D., Kerros, M. E., & Gattuso, J. P. (2009). Effect of seawater-freshwater cross-transplantations on viral dynamics and bacterial diversity and production. Aquat. Microb. Ecol., 54(1), 1–11.
Résumé: Dilution experiments were carried out to investigate the community composition and the metabolic response of seawater and freshwater bacteria to cross-transplantation, and the effects of nor.-indigenous bacterial hosts on viral dynamics. Changes in viral and bacterial abundance and production, as Well as bacterial respiration, carbon demand and diversity were regularly monitored over a 6 d period. Bacterial production in the transplanted seawater (SB-t) and freshwater (FB-t) bacteria treatments was stimulated up to 256 and 221 %, respectively, compared to controls. The stimulation of bacterial production and carbon demand was accompanied by a decrease in bacterial richness. Net viral production was stimulated by 81% in SB-t and repressed by 75% in FB-t. Transplantation increased the virus-induced mortality of marine bacteria, but decreased it for freshwater bacteria. These results suggest that (1) marine bacteria can readily oxidize freshwater dissolved organic matter, and (2) freshwater viruses might be able to infect marine hosts, thus highlighting their potential role in fueling bacterial growth under resource stress or nutrient-depleted conditions.
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Bouvy, M., Combe, M., Bettarel, Y., Dupuy, C., Rochelle-Newall, E., & Charpy, L. (2012). Uncoupled viral and bacterial distributions in coral reef waters of Tuamotu Archipelago (French Polynesia). Marine Pollution Bulletin, 65(10–12), 506–515.
Résumé: This study examined the distribution of virioplankton and bacterioplankton in two coral reef systems (Ahe and Takaroa atolls) in the Tuamotu Archipelago, in comparison with the surrounding oligotrophic ocean. Mean concentrations of 4.8 × 105 and 6.2 × 105 cells ml−1 for bacteria and 8.1 × 106 and 4.3 × 106 VLP (virus-like particle) ml−1 were recorded in Ahe and Takaroa lagoons, respectively. Chlorophyll-a concentrations and dissolved organic matter were higher in Ahe whereas 3H thymidine incorporation rates were higher in Takaroa. First data on lytic and lysogenic strategies of phages in coral reef environments were discussed in this paper. The fraction of visibly infected cells by viruses was negligible regardless of the lagoon station (mean = 0.15%). However, the fraction of lysogenic cells ranged between 2.5% and 88.9%. Our results suggest that the distribution patterns of virioplankton are apparently not coupled to the spatial dynamics of the bacterioplankton communities.
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Combe, M., Bouvier, T., Pringault, olivier., Rochelle-Newall, E., Bouvier, C., Agis, M., et al. (2013). Freshwater prokaryote and virus communities can adapt to a controlled increase in salinity through changes in their structure and interactions. Estuarine Coastal and Shelf Science, 133, 58–66.
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de Lorgeril, J., Lucasson, A., Petton, B., Toulza, E., Montagnani, C., Clerissi, C., et al. (2018). Immune-suppression by OsHV-1 viral infection causes fatal bacteraemia in Pacific oysters. Nat. Commun., 9, 4215.
Résumé: Infectious diseases are mostly explored using reductionist approaches despite repeated evidence showing them to be strongly influenced by numerous interacting host and environmental factors. Many diseases with a complex aetiology therefore remain misunderstood. By developing a holistic approach to tackle the complexity of interactions, we decipher the complex intra-host interactions underlying Pacific oyster mortality syndrome affecting juveniles of Crassostrea gigas, the main oyster species exploited worldwide. Using experimental infections reproducing the natural route of infection and combining thorough molecular analyses of oyster families with contrasted susceptibilities, we demonstrate that the disease is caused by multiple infection with an initial and necessary step of infection of oyster haemocytes by the Ostreid herpesvirus OsHV-1 mu Var. Viral replication leads to the host entering an immune-compromised state, evolving towards subsequent bacteraemia by opportunistic bacteria. We propose the application of our integrative approach to decipher other multifactorial diseases that affect non-model species worldwide.
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Doan, K. Q., Vandeputte, M., Chatain, B., Morin, T., & Allal, F. (2017). Viral encephalopathy and retinopathy in aquaculture: a review. J Fish Dis, 40(5), 717–742.
Résumé: Viral encephalopathy and retinopathy (VER), otherwise known as viral nervous necrosis (VNN), is a major devastating threat for aquatic animals. Betanodaviruses have been isolated in at least 70 aquatic animal species in marine and in freshwater environments throughout the world, with the notable exception of South America. In this review, the main features of betanodavirus, including its diversity, its distribution and its transmission modes in fish, are firstly presented. Then, the existing diagnosis and detection methods, as well as the different control procedures of this disease, are reviewed. Finally, the potential of selective breeding, including both conventional and genomic selection, as an opportunity to obtain resistant commercial populations, is examined.
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