title: Osmoregulation and salinity-induced oxidative stress: is oxidative adaptation determined by gill function?
abstract: Osmoregulating decapods such as the Mediterranean green crab Carcinus aestuarii possess two groups of spatially segregated gills: anterior gills serve mainly respiratory purposes, while posterior gills contain osmoregulatory structures. The co-existence of similar tissues serving different functions allows the study of differential adaptation, in terms of free radical metabolism, upon salinity change. Crabs were immersed for 2 weeks in seawater (SW, 37 ppt), diluted SW (dSW, 10 ppt) and concentrated SW (cSW, 45 ppt). Exposure to dSW was the most challenging condition, elevating respiration rates of whole animals and free radical formation in hemolymph (assessed fluorometrically using C-H2DFFDA). Further analyses considered anterior and posterior gills separately, and the results showed that posterior gills are the main tissues fueling osmoregulatory-related processes because their respiration rates in dSW were 3.2-fold higher than those of anterior gills, and this was accompanied by an increase in mitochondrial density (citrate synthase activity) and increased levels of reactive oxygen species (ROS) formation (1.4-fold greater, measured through electron paramagnetic resonance). Paradoxically, these posterior gills showed undisturbed caspase 3/7 activity, used here as a marker for apoptosis. This may only be due to the high antioxidant protection that posterior gills benefit from [superoxide dismutase (SOD) in posterior gills was over 6 times higher than in anterior gills]. In conclusion, osmoregulating posterior gills are better adapted to dSW exposure than respiratory anterior gills because they are capable of controlling the deleterious effects of the ROS production resulting from this salinity-induced stress.
authors.affiliation: Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), Université de Montpellier, UMR 9190 MARBEC, Place Eugène Bataillon, Montpellier 34095, France georgina.rivera-ingraham@univ-montp2.fr.
authors.forename: Georgina A
authors.initials: GA
authors.lastname: Rivera-Ingraham
authors.affiliation: Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), Université de Montpellier, UMR 9190 MARBEC, Place Eugène Bataillon, Montpellier 34095, France.
authors.forename: Kiam
authors.initials: K
authors.lastname: Barri
authors.affiliation: Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), Université de Montpellier, UMR 9190 MARBEC, Place Eugène Bataillon, Montpellier 34095, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Boël
authors.affiliation: Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), Université de Montpellier, UMR 9190 MARBEC, Place Eugène Bataillon, Montpellier 34095, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Farcy
authors.affiliation: EA 3072, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 11 rue Humann, Strasbourg 67000, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Charles
authors.affiliation: EA 3072, Fédération de Médecine Translationnelle de Strasbourg, Université de Strasbourg, 11 rue Humann, Strasbourg 67000, France.
authors.forename: Bernard
authors.initials: B
authors.lastname: Geny
authors.affiliation: Groupe fonctionnel AEO (Adaptation Ecophysiologique et Ontogenèse), Université de Montpellier, UMR 9190 MARBEC, Place Eugène Bataillon, Montpellier 34095, France.
authors.forename: Jehan-Hervé
authors.initials: JH
authors.lastname: Lignot
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D017209:Apoptosis; D003386:Brachyura / Q000502:physiology*; D005609:Free Radicals; D005880:Gills / Q000378:metabolism; D006458:Hemolymph / Q000378:metabolism; D064587:Osmoregulation; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D056152:Respiratory Rate; D054712:Salinity; D012623:Seawater / Q000737:chemistry
chemical_list: D005609:Free Radicals; D017382:Reactive Oxygen Species
keywords: Antioxidant defense; Carcinus aestuarii; Osmoregulation; ROS production