title: Osmoregulation in larvae and juveniles of two recently separated Macrobrachium species: Expression patterns of ion transporter genes.
abstract: In this comparative study, osmoregulatory mechanisms were analyzed in two closely related species of palaemonid shrimp from Brazil, Macrobrachium pantanalense and Macrobrachium amazonicum. A previous investigation showed that all postembryonic stages of M. pantanalense from inland waters of the Pantanal are able to hyper-osmoregulate in fresh water, while this species was not able to hypo-osmoregulate at high salinities. In M. amazonicum originating from the Amazon estuary, in contrast, all stages are able to hypo-osmoregulate, but only first-stage larvae, late juveniles and adults are able to hyper-osmoregulate in fresh water. The underlying molecular mechanisms of these physiological differences have not been known. We therefore investigated the expression patterns of three ion transporters (NKA α-subunit, VHA B-subunit and NHE3) following differential salinity acclimation in different ontogenetic stages (stage-V larvae, juveniles) of both species. Larval NKAα expression was at both salinities significantly higher in M. pantanalense than in M. amazonicum, whereas no difference was noted in juveniles. VHA was also more expressed in larvae of M. pantanalense than in those of M. amazonicum. When NHE3 expression is compared between the larvae of the two species, further salinity-related differences were observed, with generally higher expression in the inland species. Overall, a high expression of ion pumps in M. pantanalense suggests an evolutionary key role of these transporters in freshwater invasion.
authors.affiliation: Université Montpellier, Adaptation Ecophysiologique et Ontogenèse, UMR9190 MARBEC, cc 092, Place E. Bataillon, 34095 Montpellier cedex 05, France.
authors.forename: Nesrine
authors.initials: N
authors.lastname: Boudour-Boucheker
authors.affiliation: Ifremer, LEAD, BP2059, 98846 Nouméa Cedex, New Caledonia.
authors.forename: Viviane
authors.initials: V
authors.lastname: Boulo
authors.affiliation: Université Montpellier, Adaptation Ecophysiologique et Ontogenèse, UMR9190 MARBEC, cc 092, Place E. Bataillon, 34095 Montpellier cedex 05, France.
authors.forename: Mireille
authors.initials: M
authors.lastname: Charmantier-Daures
authors.affiliation: Alfred-Wegener-Institut für Polar- und Meeresforschung, Biologische Anstalt Helgoland, 27498 Helgoland, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Anger
authors.affiliation: Université Montpellier, Adaptation Ecophysiologique et Ontogenèse, UMR9190 MARBEC, cc 092, Place E. Bataillon, 34095 Montpellier cedex 05, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Charmantier
authors.affiliation: Université Montpellier, Adaptation Ecophysiologique et Ontogenèse, UMR9190 MARBEC, cc 092, Place E. Bataillon, 34095 Montpellier cedex 05, France. Electronic address: catherine.lorin@umontpellier.fr.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lorin-Nebel
mesh_terms: D000818:Animals; D017136:Ion Transport; D007814:Larva / Q000502:physiology*; D064587:Osmoregulation; D033541:Palaemonidae / Q000254:growth & development / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase
keywords: Branchial chamber; Crustaceans; NHE3 transporter; Na(+)/K(+)-ATPase; Salinity; V-type H(+)-ATPase