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Auteur (up) Masroor, W.; Farcy, E.; Gros, R.; Lorin-Nebel, C.
Titre Effect of combined stress (salinity and temperature) in European sea bass Dicentrarchus labrax osmoregulatory processes Type Article scientifique
Année 2018 Publication Revue Abrégée Comp. Biochem. Physiol. A-Mol. Integr. Physiol.
Volume 215 Numéro Pages 45-54
Mots-Clés Osmoregulation; fresh-water; Teleost; goldfish carassius-auratus; Ionocytes; branchial na+/k+-atpase; fish gills; gill morphology; Gill plasticity; Hydromineral balance; k+-atpase activity; mitochondria-rich cells; mozambique tilapia; NKA activity; salmon salmo-salar; Thermal acclimation; tilapia oreochromis-mossambicus
Résumé European sea bass Dicentrarchus Iabrax undertake seasonal migrations to estuaries and lagoons that are characterized by fluctuations in environmental conditions. Their ability to cope with these unstable habitats is undeniable, but it is still not clear how and to what extent salinity acclimation mechanisms are affected at temperatures higher than in the sea. In this study, juvenile sea bass were pre-acclimated to seawater (SW) at 18 degrees C (temperate) or 24 degrees C (warm) for 2 weeks and then transferred to fresh water (FW) or SW at the respective temperature. Transfer to FW for two weeks resulted in decreased blood osmolalities and plasma Cl- at both temperatures. In FW warm conditions, plasma Na+ was similar to 15% lower and Cl- was similar to 32% higher than in the temperate-water group. Branchial Na+/K+-ATPase (NKA) activity measured at the acclimation temperature (V-apparent) did not change according to the conditions. Branchial Na+/K+-ATPase activity measured at 37 degrees C (V-max) was lower in warm conditions and increased in FW compared to SW conditions whatever the considered temperature. Mitochondrion-rich cell (MRC) density increased in FW, notably due to the appearance of lamellar MRCs, but this increase was less pronounced in warm conditions where MRC's size was lower. In SW warm conditions, pavement cell apical microridges are less developed than in other conditions. Overall gill morphometrical parameters (filament thickness, lamellar length and width) differ between fish that have been pre acclimated to different temperatures. This study shows that a thermal change affects gill plasticity affecting whole-organism ion balance two weeks after salinity transfer.
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ISSN 1095-6433 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2260
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Auteur (up) Meynard, C.N.; Mouillot, D.; Mouquet, N.; Douzery, E.J.P.
Titre A Phylogenetic Perspective on the Evolution of Mediterranean Teleost Fishes Type Article scientifique
Année 2012 Publication Revue Abrégée PLoS One
Volume 7 Numéro 5 Pages
Mots-Clés cytochrome-b; divergence time; diversification; dna sequences; missing data; mitochondrial genome sequences; molecular phylogeny; nuclear; ray-finned fishes; tetraodontiform fishes
Résumé The Mediterranean Sea is a highly diverse, highly studied, and highly impacted biogeographic region, yet no phylogenetic reconstruction of fish diversity in this area has been published to date. Here, we infer the timing and geographic origins of Mediterranean teleost species diversity using nucleotide sequences collected from GenBank. We assembled a DNA supermatrix composed of four mitochondrial genes (12S ribosomal DNA, 16S ribosomal DNA, cytochrome c oxidase subunit I and cytochrome b) and two nuclear genes (rhodopsin and recombination activating gene I), including 62% of Mediterranean teleost species plus 9 outgroups. Maximum likelihood and Bayesian phylogenetic and dating analyses were calibrated using 20 fossil constraints. An additional 124 species were grafted onto the chronogram according to their taxonomic affinity, checking for the effects of taxonomic coverage in subsequent diversification analyses. We then interpreted the time-line of teleost diversification in light of Mediterranean historical biogeography, distinguishing non-endemic natives, endemics and exotic species. Results show that the major Mediterranean orders are of Cretaceous origin, specifically similar to 100-80 Mya, and most Perciformes families originated 80-50 Mya. Two important clade origin events were detected. The first at 100-80 Mya, affected native and exotic species, and reflects a global diversification period at a time when the Mediterranean Sea did not yet exist. The second occurred during the last 50 Mya, and is noticeable among endemic and native species, but not among exotic species. This period corresponds to isolation of the Mediterranean from Indo-Pacific waters before the Messinian salinity crisis. The Mediterranean fish fauna illustrates well the assembly of regional faunas through origination and immigration, where dispersal and isolation have shaped the emergence of a biodiversity hotspot.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 408
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Auteur (up) Oikonomou, A.; Leprieur, F.; Leonardos, I.D.
Titre Biogeography of freshwater fishes of the Balkan Peninsula Type Article scientifique
Année 2014 Publication Revue Abrégée Hydrobiologia
Volume 738 Numéro 1 Pages 205-220
Mots-Clés Balkan Peninsula; Beta diversity; Bioregionalisation; Conservation biogeography; Vulnerability; ancient lakes; biodiversity conservation; endemism; freshwater fish; global patterns; mitochondrial-dna sequences; north-america; phylogeography; species richness
Résumé Delineating biogeographical regions is a critical step towards the establishment and evaluation of conservation priorities. In the present study, we analysed the distribution patterns of the freshwater fish of an understudied European biodiversity hotspot, the Balkan Peninsula. Based on the most extensive available database of native freshwater fish species distributions, we performed a hierarchical clustering analysis to identify the major biogeographical regions of the Balkan Peninsula. We also highlighted the 'hottest hotspots' of freshwater fish diversity across the delimited biogeographical regions by describing the patterns of species richness, endemic and vulnerable species; indicator species were also determined. The bioregionalisation scheme consisted of eight groups of drainage basins that correspond to distinct regions of the Balkan Peninsula. Overall, the delineated biogeographical regions varied in terms of species richness, endemism, vulnerability (i.e. extinction threats) and indicator species composition. From a conservation perspective, this study emphasises the prioritisation of areas characterised by high levels of irreplaceability (endemism) and vulnerability (i.e. the Attikobeotia region, Ionian Sea and Prespa Lakes) and stresses the necessity of implementing a network of protected freshwater areas across the Balkan Peninsula.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0018-8158 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 454
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Auteur (up) Rivera-Ingraham, G.A.; Lignot, J.-H.
Titre Osmoregulation, bioenergetics and oxidative stress in coastal marine invertebrates: raising the questions for future research Type Article scientifique
Année 2017 Publication Revue Abrégée J. Exp. Biol.
Volume 220 Numéro 10 Pages 1749-1760
Mots-Clés Antioxidants; callinectes-sapidus; cell-volume regulation; clibanarius-vittatus bosc; copepod tigriopus-brevicornis; crab chasmagnathus-granulata; different salinity levels; free amino-acids; Free radicals; Hyper-/hypo-osmoregulator; Hyper-/iso-osmoregulators; Hypometabolism; metabolic depression; Mitochondria; Osmoconformers; oxygen species production; reactive oxygen
Résumé Osmoregulation is by no means an energetically cheap process, and its costs have been extensively quantified in terms of respiration and aerobic metabolism. Common products of mitochondrial activity are reactive oxygen and nitrogen species, which may cause oxidative stress by degrading key cell components, while playing essential roles in cell homeostasis. Given the delicate equilibrium between pro- and antioxidants in fueling acclimation responses, the need for a thorough understanding of the relationship between salinity-induced oxidative stress and osmoregulation arises as an important issue, especially in the context of global changes and anthropogenic impacts on coastal habitats. This is especially urgent for intertidal/estuarine organisms, which may be subject to drastic salinity and habitat changes, leading to redox imbalance. How do osmoregulation strategies determine energy expenditure, and how do these processes affect organisms in terms of oxidative stress? What mechanisms are used to cope with salinity-induced oxidative stress? This Commentary aims to highlight the main gaps in our knowledge, covering all levels of organization. From an energy-redox perspective, we discuss the link between environmental salinity changes and physiological responses at different levels of biological organization. Future studies should seek to provide a detailed understanding of the relationship between osmoregulatory strategies and redox metabolism, thereby informing conservation physiologists and allowing them to tackle the new challenges imposed by global climate change.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0022-0949 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2140
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Auteur (up) Rivera-Ingraham, G.A.; Nommick, A.; Blondeau-Bidet, E.; Ladurner, P.; Lignot, J.-H.
Titre Salinity stress from the perspective of the energy-redox axis: Lessons from a marine intertidal flatworm Type Article scientifique
Année 2016 Publication Revue Abrégée Redox Biology
Volume 10 Numéro Pages 53-64
Mots-Clés Energetic balance; Flatworms; Live-imaging; Mitochondrial membrane potential; Osmoregulation; Rns; Ros
Résumé In the context of global change, there is an urgent need for researchers in conservation physiology to understand the physiological mechanisms leading to the acquisition of stress acclimation phenotypes. Intertidal organisms continuously cope with drastic changes in their environmental conditions, making them outstanding models for the study of physiological acclimation. As the implementation of such processes usually comes at a high bioenergetic cost, a mitochondrial/oxidative stress approach emerges as the most relevant approach when seeking to analyze whole-animal responses. Here we use the intertidal flatworm Macrostomum lignano to analyze the bioenergetics of salinity acclimation and its consequences in terms of reactive oxygen/nitrogen species formation and physiological response to counteract redox imbalance. Measures of water fluxes and body volume suggest that M. lignano is a hyper-/iso-regulator. Higher salinities were revealed to be the most energetically expensive conditions, with an increase in mitochondrial density accompanied by increased respiration rates. Such modifications came at the price of enhanced superoxide anion production, likely associated with a high caspase 3 upregulation. These animals nevertheless managed to live at high levels of environmental salinity through the upregulation of several mitochondrial antioxidant enzymes such as superoxide dismutase. Contrarily, animals at low salinities decreased their respiration rates, reduced their activity and increased nitric oxide formation, suggesting a certain degree of metabolic arrest. A contradictory increase in dichlorofluorescein fluorescence and an upregulation of gluthathione-S-transferase pi 1 (GSTP1) expression were observed in these individuals. If animals at low salinity are indeed facing metabolic depression, the return to seawater may result in an oxidative burst. We hypothesize that this increase in GSTP1 could be a “preparation for oxidative stress”, i.e. a mechanism to counteract the production of free radicals upon returning to seawater. The results of the present study shed new light on how tolerant organisms carry out subcellular adaptations to withstand environmental change.
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Volume de collection Numéro de collection Edition
ISSN 2213-2317 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2408
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