Excellent Salinity Tolerance of Mozambique Tilapia (Oreochromis mossambicus): Elevated Chloride Cell Activity in the Branchial and Opercular Epithelia of the Fish Adapted to Concentrated Seawater

Uchida, Katsuhisa; Kaneko, Toyoji; Mitsuya, Hiroaki; Hasegawa, Sanaé; Hirano, Tetsuya

doi:10.2108/zsj.17.149

Cited by 157 publications

(124 citation statements)

References 36 publications

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“…This argument is also supported by a relatively slow increase in NKA activity in gills of tilapia following salinity transfer (Dange 1985;Hwang et al 1989). Likewise, signiWcant changes in MRC size only occurred several days after the onset of MRC apoptosis, which is consistent with previous studies based on MRC DASPMI staining and electron microscopy (Cioni et al 1991;Uchida et al 2000;Van Der Heijden et al 1997).…”

Section: Discussionsupporting

confidence: 89%

Prolonged apoptosis in mitochondria-rich cells of tilapia (Oreochromis mossambicus) exposed to elevated salinity

Kammerer

Kültz

2009

J Comp Physiol B

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The time-course of programmed cell death (apoptosis) during reorganization of gill epithelium in salinity-stressed tilapia was analyzed using a recently developed method based on laser scanning cytometry (LSC) of dissociated gill cells. Apoptosis in mitochondriarich cells (MRC) was distinguished from that in other cell types using Na + /K + ATPase (NKA) as a cell-speciWc marker. Caspase 3/7 activity in MRC, assessed using LSC and microplate assays, increased signiWcantly starting at 6 h of salinity stress and remained elevated for at least 5 days. This time-course of apoptosis in MRC during acute salinity stress was reXected in elevated apoptotic DNA fragmentation. In parallel to induction of apoptosis, MRC showed a pronounced shift to G2 phase of the cell cycle, which is indicative of G2/M cell cycle arrest, and an increase in NKA abundance per MRC. Unlike in MRC, apoptosis was not signiWcantly increased in other gill cell types, although there was a small transient increase in DNA fragmentation at 6 h. G2 arrest was also observed. Overall, we interpret our data as evidence for a signiWcant role of apoptosis in the extensive reorganization of MRC populations that takes place during salinity acclimation, perhaps similar to its well-established role during organismal development.

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Section: Discussionsupporting

confidence: 89%

Prolonged apoptosis in mitochondria-rich cells of tilapia (Oreochromis mossambicus) exposed to elevated salinity

Kammerer

Kültz

2009

J Comp Physiol B

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“…Morphology and physiology of the gill chloride cells have been studied extensively (18)(19)(20). Recently, various ion transporters have been identified in the chloride cells (21)(22)(23)(24).…”

Section: Discussionmentioning

confidence: 99%

Kidney-specific chloride channel, OmClC-K, predominantly expressed in the diluting segment of freshwater-adapted tilapia kidney

Mitsuya

Kaneko²,

Uchida³

et al. 2002

Proc. Natl. Acad. Sci. U.S.A.

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The kidney plays an important role in osmoregulation in freshwater teleosts, which are exposed to the danger of osmotic loss of Na ؉ and Cl ؊ . However, ion-transport mechanisms in the kidney are poorly understood, and ion transporters of the fish nephron have not been identified thus far. From Mozambique tilapia, Oreochromis mossambicus, we have cloned a chloride channel, which is a homologue of the mammalian kidney-specific chloride channel, ClC-K. The cDNA of the channel, named OmClC-K, encodes a protein whose amino acid sequence has high homology to Xenopus and mammalian ClC-K (Xenopus ClC-K, 41.8%; rat ClC-K2, 40.9%; rat ClC-K1, 40.1%). The mRNA of OmClC-K was expressed exclusively in the kidney, and the expression level of mRNA was increased more in freshwater-adapted fish than seawater-adapted fish. The immunohistochemical study using a specific antibody showed that OmClC-K-positive cells were specifically located in the distal nephron segments. Immunoelectron microscopy further showed that immunoreaction of OmClC-K was recognizable on the structure of basolateral membrane infoldings in the distal tubule cells. The localization of OmClC-K and its induction in hypoosmotic media suggest that OmClC-K is involved in Cl ؊ reabsorption in the distal tubule of freshwater-adapted tilapia.T he kidney plays an important role in osmoregulation in both freshwater and seawater teleosts, although its function is entirely different under the two different environmental conditions. Freshwater teleosts are exposed to the danger of osmotic water load and ion loss. Accordingly, the primary function of their kidneys is to excrete excess water, while reabsorbing most of the filtered solutes. The glomerular filtration rate of freshwater teleosts is higher than that of marine teleosts, and sometimes as much as 95% of the filtered water is excreted as copious dilute urine, which implies that the renal tubules of freshwater teleosts must generally have low water permeability. The nephron of freshwater teleosts is composed of a well-developed glomerulus, a ciliated neck segment, a proximal tubule, an intermediate segment, a distal tubule, and a collecting tubule, but it lacks the loop of Henle (1). The teleost kidney exhibits neither zonation, such as the cortex and medulla, nor a countercurrent system of tubular elements. Thus, teleosts are not able to excrete hyperosmotic urine.Nishimura et al. (2) measured water and ion transport in nephron tubules isolated from freshwater-adapted rainbow trout, Oncorhynchus mykiss. They perfused nephron tubules and measured water and ion transport in the distal tubule. These results suggest that in freshwater-adapted rainbow trout, the distal tubule acts as a diluting segment, which is equivalent to the early distal segment of the frog kidney and the mammalian thick ascending limb of Henle's loop (TALH) (3, 4).The extraction of NaCl from urine in the TALH is crucial to urinary concentration and dilution, which is accomplished by the active reabsorption of NaCl in the water-impermeable epitheli...

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“…Both species are highly euryhaline; however, their acclimation 'strategy' in molecular terms seems different when exposed to increasing salinity. The Mozambique tilapia develops the appropriate hypo-osmoregulatory mechanisms gradually when stimulated by increased salinity (Morgan et al 1997, Uchida et al 2000. Thus, the energy to build the appropriate mechanisms is only spent when needed.…”

Section: Introductionmentioning

confidence: 99%

Differential effects of cortisol and 11-deoxycorticosterone on ion transport protein mRNA levels in gills of two euryhaline teleosts, Mozambique tilapia (Oreochromis mossambicus) and striped bass (Morone saxatilis)

Kiilerich¹,

Tipsmark²,

Borski³

et al. 2011

Journal of Endocrinology

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The role of cortisol as the only corticosteroid in fish osmoregulation has recently been challenged with the discovery of a mineralocorticoid-like hormone, 11-deoxycorticosterone (DOC), and necessitates new studies of the endocrinology of osmoregulation in fish. Using an in vitro gill explant incubation approach, DOC-mediated regulation of selected osmoregulatory target genes in the gill was investigated and compared with that of cortisol in two euryhaline teleosts, Mozambique tilapia (Oreochromis mossambicus) and striped bass (Morone saxatilis). The effects were tested in gills from both fresh water (FW)-and seawater (SW)-acclimated fish. Both cortisol and DOC caused an up-regulation of the Na C ,K C -ATPase a1 subunit in SW-acclimated tilapia but had no effect in FW-acclimated fish. Cortisol conferred an increase in NaK cotransporter (NKCC) isoform 1a transcript levels in FW-and SW-acclimated tilapia, whereas DOC had a stimulatory effect only in SW-acclimated fish. Cortisol had no effect on NKCC isoform 1b mRNA levels at both salinities, while DOC stimulated this isoform in SW-acclimated fish. In striped bass, cortisol conferred an up-regulation of Na C ,K C -ATPase a1 and NKCC transcript levels in FW-and SW-acclimated fish, whereas DOC resulted in down-regulation of these transcripts in FW-acclimated fish. It was also found that both corticosteroids may rapidly (30 min) alter the mitogen-activated protein kinase signalling pathway in gill, inducing phosphorylation of extracellular signalregulated kinase 1 (ERK1) and ERK2 in a salinity-dependent manner. The study shows a disparate organisation of corticosteroid signalling mechanisms involved in ion regulation in the two species and adds new evidence to a role of DOC as a mineralocorticoid hormone in teleosts.

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Excellent Salinity Tolerance of Mozambique Tilapia (Oreochromis mossambicus): Elevated Chloride Cell Activity in the Branchial and Opercular Epithelia of the Fish Adapted to Concentrated Seawater

Abstract: BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

Cited by 157 publications

References 36 publications

Prolonged apoptosis in mitochondria-rich cells of tilapia (Oreochromis mossambicus) exposed to elevated salinity

Prolonged apoptosis in mitochondria-rich cells of tilapia (Oreochromis mossambicus) exposed to elevated salinity

Kidney-specific chloride channel, OmClC-K, predominantly expressed in the diluting segment of freshwater-adapted tilapia kidney

Differential effects of cortisol and 11-deoxycorticosterone on ion transport protein mRNA levels in gills of two euryhaline teleosts, Mozambique tilapia (Oreochromis mossambicus) and striped bass (Morone saxatilis)

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