Immunolocalization and expression of Na+/K+-ATPase in embryos, early larval stages and adults of the freshwater shrimp Palaemonetes argentinus (Decapoda, Caridea, Palaemonidae)

ITUARTE, ROMINA B.; LIGNOT, JEHAN-HERVÉ; CHARMANTIER, GUY; SPIVAK, EDUARDO D.; LORIN-NEBEL, CATHERINE

CELL AND TISSUE RESEARCH

SPRINGER

Lugar: Berlin; Año: 2016

0302-766X

The euryhaline shrimp Palaemonetes argentinus exemplifies an evolutionary transition from brackish to freshwater habitats that requires adequate osmoregulatory capacities.Hyperosmoregulationisfunctionalathatchinganditlikely begins during the embryonic phase allowing this species to developentirelyinfreshwater.Here,weinvestigatedtheNa+/ 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.Werearedshrimpsfromspawningtojuvenilestages 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 expressionwas 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.