title: Immunolocalization and expression of Na(+)/K(+) -ATPase in embryos, early larval stages and adults of the freshwater shrimp Palaemonetes argentinus (Decapoda, Caridea, Palaemonidae).
abstract: The euryhaline shrimp Palaemonetes argentinus exemplifies an evolutionary transition from brackish to freshwater habitats that requires adequate osmoregulatory capacities. Hyperosmoregulation is functional at hatching and it likely begins during the embryonic phase allowing this species to develop entirely in fresh water. Here, we investigated the Na(+)/K(+)-ATPase α-subunit gene (nka-α) expression using quantitative real-time PCR and localized Na(+)/K(+)-ATPase (NKA) in ion-transporting epithelia through immunofluorescence microscopy. We reared shrimps from spawning to juvenile stages at two salinities (1, 15 ‰) and maintained adults for 3 weeks at three salinity treatments (1, 15, 25 ‰). nka-α gene expression was measured in: (1) embryos at an early (SI), intermediate (SII) and late (SIII) stage of embryonic development; (2) newly hatched larvae (Zoea I, ZI); and (3) isolated gill tissue of adults. The nka-α expression was low in SI and SII embryos and reached maximum levels prior to hatching (SIII), which were similar to expression levels detected in the ZI. The nka-α expression in SIII and ZI was highest at 15 ‰, whereas salinity did not affect expression in earlier embryos. In SIII, in ZI and in a later zoeal stage ZIV, NKA was localized in epithelial cells of pleurae, in the inner-side epithelium of branchiostegite and in the antennal glands. Gills appeared in the ZIV but NKA immunolabeling of the cells of the gill shaft occurred in a subsequent developmental larval stage, the decapodid. Extrabranchial organs constitute the main site of osmoregulation in early ontogenetic stages of this freshwater shrimp.
authors.affiliation: Grupo Zoología Invertebrados, Instituto de Investigaciones Marinas y Costeras, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Mar del Plata, Dean Funes 3250, 7600, Mar del Plata, Argentina. ituarte@mdp.edu.ar.
authors.forename: Romina Belén
authors.initials: RB
authors.lastname: Ituarte
authors.affiliation: Groupe Fonctionnel Adaptation Ecophysiologique et Ontogenèse, UMR 9190 MARBEC, UM-CNRS-IRD-Ifremer, Université Montpellier, cc 092, Place E. Bataillon, 34095, Montpellier cedex 05, France.
authors.forename: Jehan-Hervé
authors.initials: JH
authors.lastname: Lignot
authors.affiliation: Groupe Fonctionnel Adaptation Ecophysiologique et Ontogenèse, UMR 9190 MARBEC, UM-CNRS-IRD-Ifremer, Université Montpellier, cc 092, Place E. Bataillon, 34095, Montpellier cedex 05, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Charmantier
authors.affiliation: Grupo Zoología Invertebrados, Instituto de Investigaciones Marinas y Costeras, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de Mar del Plata, Dean Funes 3250, 7600, Mar del Plata, Argentina.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Spivak
authors.affiliation: Groupe Fonctionnel Adaptation Ecophysiologique et Ontogenèse, UMR 9190 MARBEC, UM-CNRS-IRD-Ifremer, Université Montpellier, cc 092, Place E. Bataillon, 34095, Montpellier cedex 05, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lorin-Nebel
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000201:enzymology*; D005618:Fresh Water; D015971:Gene Expression Regulation, Enzymologic; D005880:Gills / Q000648:ultrastructure; D007814:Larva / Q000201:enzymology; D064587:Osmoregulation; D033541:Palaemonidae / Q000033:anatomy & histology / Q000196:embryology* / Q000201:enzymology* / Q000648:ultrastructure; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D054712:Salinity; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D012333:RNA, Messenger; D000254:Sodium-Potassium-Exchanging ATPase
keywords: Antennal gland; Extrabranchial organs; Gill; Ontogeny; Osmoregulation