INVESTIGADORES
LOPEZ MAÑANES Alejandra Antonia
artículos
Título:
Activity of Na+-K+-ATPase in a "freshwater shrimp", Palaemonetes argentinus (Caridea, Palaemonidae): ontogenetic and salinity-induced changes
Autor/es:
ITUARTE, R.; LOPEZ MAÑANES A.A.; SPIVAK, E.; ANGER, K.
Revista:
Aquatic Biology
Editorial:
Inter-research
Referencias:
Año: 2008 vol. 3 p. 283 - 290
ISSN:
1864-7782
Resumen:
Embryos, larvae, and adults of Palaemonetes argentinus tolerate a wide range of salinities
(1 to 25). While osmoregulatory capacities have previously been demonstrated in all postembryonic
stages, little is known about the occurrence of osmoregulation during the embryonic
phase. We examined ontogenetic and salinity-induced changes in the activity of a key enzyme
involved in osmoregulation, Na+,K+-ATPase. Its activity was studied in: (1) eggs at an early (SI), an
intermediate (SII), and a late stage of embryonic development (SIII); (2) in newly hatched larvae
(Zoea-I, ZI); and in homogenates of (3) whole adults and (4) isolated gill tissue. All stages were
directly exposed to 1, 15, or 25, and Na+,K+-ATPase activity was chemically determined 24 h
(embryos, larvae) or 48 h later (adults). Enzyme activity was detected in all developmental stages,
being low in SI and SII, maximum in SIII, and intermediate in ZI and adults. Maximum salinityinduced
activity changes prior to hatching (SIII) suggest that hyper-osmoregulatory functions are
expressed by the end of the embryonic phase. The ontogenetic activity maximum at this stage, however,
may also be related to the hatching process. Comparing different salinities, Na+,K+-ATPase
activity in SIII was always highest at 15, whereas the activity in gills was higher at both 15 and 25
than at 1. While gills are absent in the embryonic and early larval stages, ion-transporting cells
must be located elsewhere during these early ontogenetic stages, probably in the brachiostegites.Palaemonetes argentinus tolerate a wide range of salinities
(1 to 25). While osmoregulatory capacities have previously been demonstrated in all postembryonic
stages, little is known about the occurrence of osmoregulation during the embryonic
phase. We examined ontogenetic and salinity-induced changes in the activity of a key enzyme
involved in osmoregulation, Na+,K+-ATPase. Its activity was studied in: (1) eggs at an early (SI), an
intermediate (SII), and a late stage of embryonic development (SIII); (2) in newly hatched larvae
(Zoea-I, ZI); and in homogenates of (3) whole adults and (4) isolated gill tissue. All stages were
directly exposed to 1, 15, or 25, and Na+,K+-ATPase activity was chemically determined 24 h
(embryos, larvae) or 48 h later (adults). Enzyme activity was detected in all developmental stages,
being low in SI and SII, maximum in SIII, and intermediate in ZI and adults. Maximum salinityinduced
activity changes prior to hatching (SIII) suggest that hyper-osmoregulatory functions are
expressed by the end of the embryonic phase. The ontogenetic activity maximum at this stage, however,
may also be related to the hatching process. Comparing different salinities, Na+,K+-ATPase
activity in SIII was always highest at 15, whereas the activity in gills was higher at both 15 and 25
than at 1. While gills are absent in the embryonic and early larval stages, ion-transporting cells
must be located elsewhere during these early ontogenetic stages, probably in the brachiostegites.+,K+-ATPase. Its activity was studied in: (1) eggs at an early (SI), an
intermediate (SII), and a late stage of embryonic development (SIII); (2) in newly hatched larvae
(Zoea-I, ZI); and in homogenates of (3) whole adults and (4) isolated gill tissue. All stages were
directly exposed to 1, 15, or 25, and Na+,K+-ATPase activity was chemically determined 24 h
(embryos, larvae) or 48 h later (adults). Enzyme activity was detected in all developmental stages,
being low in SI and SII, maximum in SIII, and intermediate in ZI and adults. Maximum salinityinduced
activity changes prior to hatching (SIII) suggest that hyper-osmoregulatory functions are
expressed by the end of the embryonic phase. The ontogenetic activity maximum at this stage, however,
may also be related to the hatching process. Comparing different salinities, Na+,K+-ATPase
activity in SIII was always highest at 15, whereas the activity in gills was higher at both 15 and 25
than at 1. While gills are absent in the embryonic and early larval stages, ion-transporting cells
must be located elsewhere during these early ontogenetic stages, probably in the brachiostegites.+,K+-ATPase activity was chemically determined 24 h
(embryos, larvae) or 48 h later (adults). Enzyme activity was detected in all developmental stages,
being low in SI and SII, maximum in SIII, and intermediate in ZI and adults. Maximum salinityinduced
activity changes prior to hatching (SIII) suggest that hyper-osmoregulatory functions are
expressed by the end of the embryonic phase. The ontogenetic activity maximum at this stage, however,
may also be related to the hatching process. Comparing different salinities, Na+,K+-ATPase
activity in SIII was always highest at 15, whereas the activity in gills was higher at both 15 and 25
than at 1. While gills are absent in the embryonic and early larval stages, ion-transporting cells
must be located elsewhere during these early ontogenetic stages, probably in the brachiostegites.+,K+-ATPase
activity in SIII was always highest at 15, whereas the activity in gills was higher at both 15 and 25
than at 1. While gills are absent in the embryonic and early larval stages, ion-transporting cells
must be located elsewhere during these early ontogenetic stages, probably in the brachiostegites.