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Le Chevanton, M., Garnier, M., Bougaran, G., Schreiber, N., Lukomska, E., Bérard, J. B., et al. (2013). Screening and selection of growth-promoting bacteria for Dunaliella cultures. Algal Research, 2, 212–222.
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Massol, F., Altermatt, F., Gounand, I., Gravel, D., Leibold, M. A., & Mouquet, N. (2017). How life-history traits affect ecosystem properties: effects of dispersal in meta-ecosystems. Oikos, 126(4), 532–546.
Résumé: The concept of life-history traits and the study of these traits are the hallmark of population biology. Acknowledging their variability and evolution has allowed us to understand how species adapt in response to their environment. The same traits are also involved in how species alter ecosystems and shape their dynamics and functioning. Some theories, such as the metabolic theory of ecology, ecological stoichiometry or pace-of-life theory, already recognize this junction, but only do so in an implicitly non-spatial context. Meanwhile, for a decade now, it has been argued that ecosystem properties have to be understood at a larger scale using meta-ecosystem theory because source-sink dynamics, community assembly and ecosystem stability are all modified by spatial structure. Here, we argue that some ecosystem properties can be linked to a single life-history trait, dispersal, i.e. the tendency of organisms to live, compete and reproduce away from their birth place. By articulating recent theoretical and empirical studies linking ecosystem functioning and dynamics to species dispersal, we aim to highlight both the known connections between life-history traits and ecosystem properties and the unknown areas, which deserve further empirical and theoretical developments.
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Meistertzheim, A. - L., Lartaud, F., Arnaud-Haond, S., Kalenitchenko, D., Bessalam, M., Le Bris, N., et al. (2016). Patterns of bacteria-host associations suggest different ecological strategies between two reef building cold-water coral species. Deep Sea Research Part I: Oceanographic Research Papers, 114, 12–22.
Résumé: Cold-water corals (CWC) are main ecosystem engineers of the deep sea, and their reefs constitute hot-spots of biodiversity. However, their ecology remains poorly understood, particularly, the nature of the holobiont formed by corals with their associated bacterial communities. Here, we analyzed Madrepora oculata and Lophelia pertusa samples, collected from one location in a Mediterranean canyon in two different seasons (autumn and spring), in order to test for species specificity and temporal stability of the host-bacteria associations. The 16S rRNA sequencing revealed host-specific patterns of bacterial communities associated with L. pertusa and M. oculata, both in terms of community composition and diversity. All analyzed M. oculata polyps exhibited temporally and spatially similar bacterial communities dominated by haplotypes homologous to the known cnidarians-associated genus Endozoicomonas. In contrast, the bacterial communities associated with L. pertusa varied among polyps from the same colony, as well as among distinct colonies and between seasons. While the resilient consortium formed by M. oculata and its bacterial community fit the definition of holobiont, the versatility of the L. pertusa microbiome suggests that this association is more influenced by the environmental conditions or nutritional status. Our results thus highlight distinct host/microbes association strategies for these two closely related Scleractinians sharing the same habitat, suggesting distinct sensitivity to environmental change.
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Minguez, L., Farcy, E., Ballandonne, C., Lepailleur, A., Serpentini, A., Lebel, J. M., et al. (2014). Acute toxicity of 8 antidepressants: What are their modes of action? Chemosphere, 108, 314–319.
Résumé: Currently, the hazard posed by pharmaceutical residues is a major concern of ecotoxicology. Most of the antidepressants belong to a family named the Cationic Amphipathic Drugs known to have specific interactions with cell membranes. The present study assessed the impact of eight antidepressants belonging to selective serotonin reuptake inhibitors or serotonin norepinephrine reuptake inhibitors by the combination of multi-approaches (in vivo, in vitro, in silico) and gives some insights on the mode of action for these molecules. Antidepressants were from the most to the least toxic compound for Daphnia magna: Sertraline (EC50 = 1.15 mg L-1) > Clomipramine (2.74 mg L-1)> Amitriptyline (4.82 mg L-1)> Fluoxetine (5.91 mg L-1) > Paroxetine (6.24 mg L-1) > Mianserine (7.81 mg L-1) > Citalopram (30.14 mg L-1) and Venlafaxine (141.28 mg L-1). These acute toxicities were found correlated to Log K, coefficients (R = 0.93, p < 0.001) and to cytotoxicity assessed on abalone hemocytes through the neutral red uptake assay (R = 0.96, p < 0.001). If narcosis as mode of action is typically expected during acute ecotoxicity bioassays, we showed by molecular modeling that particular interactions can exist between antidepressants and phosphatidylcholine, a major component of cell membranes, leading to a more specific mode of action corresponding to a potential acidic hydrolysis of ester functions. (C) 2014 Elsevier Ltd. All rights reserved.
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Mostajir, B., Amblard, C., Buffan-Dubau, E., De Wit, R., Lensi, R., & Sime-Ngando, T. (2015). Microbial Food Webs in Aquatic and Terrestrial Ecosystems. In J. - C. Bertrand, P. Caumette, P. Lebaron, R. Matheron, P. Normand, & T. Sime-Ngando (Eds.), (pp. 485–509). Environmental Microbiology: Fundamentals and Applications. Springer Netherlands.
Résumé: In microbial food webs, different types of interactions occur between microorganisms themselves and with meio- and macroorganisms. After an historical and general introduction, the biological components of the microbial food webs in the pelagic and benthic marine and lake ecosystems, as well as in the terrestrial ecosystems, are presented. The functioning of the microbial food webs in different ecosystems is illustrated and explained, including the trophic pathways and transfer of matter from microbial food webs toward meio- and macroorganisms of the superior trophic levels, the nutrient recycling in the aquatic environments, and the decomposition of organic matter in soils. Finally, the factors regulating microbial food webs, primarily “top-down” and “bottom-up” controls, are described with a special focus on the role of viruses in the aquatic microbial food webs.
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