Some mechanisms of salinity acclimation in the euryhaline teleost, Etroplus maculatus

1967 ◽  
Vol 1 (2) ◽  
pp. 97-101 ◽  
Author(s):  
V. Parvatheswararao
Keyword(s):  
Salinity Acclimation ◽  
Euryhaline Teleost

scholarly journals Evidence for a role of arginine vasotocin receptors in the gill during salinity acclimation by a euryhaline teleost fish

2019 ◽  
Vol 316 (6) ◽  
pp. R735-R750 ◽  
Author(s):  
Sean C. Lema ◽  
Elsie H. Washburn ◽  
Mary E. Crowley ◽  
Paul G. Carvalho ◽  
Jennifer N. Egelston ◽  
...  
Keyword(s):  
Transcript Abundance ◽  
Arginine Vasotocin ◽  
Teleost Fishes ◽  
Salinity Acclimation ◽  
Receptor Inhibition ◽  
Osmotic Balance ◽  
Euryhaline Teleost ◽  
Seawater Acclimation ◽  
Type Receptor

The nonapeptide arginine vasotocin (AVT) regulates osmotic balance in teleost fishes, but its mechanisms of action are not fully understood. Recently, it was discovered that nonapeptide receptors in teleost fishes are differentiated into two V1a-type, several V2-type, and two isotocin (IT) receptors, but it remains unclear which receptors mediate AVT’s effects on gill osmoregulation. Here, we examined the role of nonapeptide receptors in the gill of the euryhaline Amargosa pupfish ( Cyprinodon nevadensis amargosae) during osmotic acclimation. Transcripts for the teleost V1a-type receptor v1a2 were upregulated over fourfold in gill 24 h after transferring pupfish from 7.5 ppt to seawater (35 ppt) or hypersaline (55 ppt) conditions and downregulated after transfer to freshwater (0.3 ppt). Gill transcripts for the nonapeptide degradation enzyme leucyl-cystinyl aminopeptidase (LNPEP) also increased in fish acclimating to 35 ppt. To test whether the effects of AVT on the gill might be mediated by a V1a-type receptor, we administered AVT or a V1-type receptor antagonist (Manning compound) intraperitoneally to pupfish before transfer to 0.4 ppt or 35 ppt. Pupfish transferred to 35 ppt exhibited elevated gill mRNA abundance for cystic fibrosis transmembrane conductance regulator ( cftr), but that upregulation diminished under V1-receptor inhibition. AVT inhibited the increase in gill Na+/Cl− cotransporter 2 ( ncc2) transcript abundance that occurs following transfer to hypoosmotic environments, whereas V1-type receptor antagonism increased ncc2 mRNAs even without a change in salinity. These findings indicate that AVT acts via a V1-type receptor to regulate gill Cl− transport by inhibiting Cl− uptake and facilitating Cl− secretion during seawater acclimation.

scholarly journals Transcriptomic Analysis of Gill and Kidney from Asian Seabass (Lates calcarifer) Acclimated to Different Salinities Reveals Pathways Involved with Euryhalinity

Genes ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 733 ◽  
Author(s):  
Shubha Vij ◽  
Kathiresan Purushothaman ◽  
Prakki Sai Rama Sridatta ◽  
Dean R. Jerry
Keyword(s):  
Cell Volume Regulation ◽  
Initial Step ◽  
Lates Calcarifer ◽  
Salinity Acclimation ◽  
Asian Seabass ◽  
The Family ◽  
Freshwater Habitats ◽  
Acclimation Response ◽  
Euryhaline Teleost ◽  
Expression Pathways

Asian seabass (or commonly known as barramundi), Lates calcarifer, is a bony euryhaline teleost from the Family Latidae, inhabiting nearshore, estuarine, and marine connected freshwaters throughout the tropical Indo-West Pacific region. The species is catadromous, whereby adults spawn in salinities between 28 and 34 ppt at the mouth of estuaries, with resultant juveniles usually moving into brackish and freshwater systems to mature, before returning to the sea to spawn again as adults. The species lives in both marine and freshwater habitats and can move quickly between the two; thus, the species’ ability to tolerate changes in salinity makes it a good candidate for studying the salinity acclimation response in teleosts. In this study, the transcriptome of two major osmoregulatory organs (gills and kidneys) of young juvenile Asian seabass reared in freshwater and seawater were compared. The euryhaline nature of Asian seabass was found to be highly pliable and the moldability of the trait was further confirmed by histological analyses of gills and kidneys. Differences in major expression pathways were observed, with differentially expressed genes including those related to osmoregulation, tissue/organ morphogenesis, and cell volume regulation as central to the osmo-adaptive response. Additionally, genes coding for mucins were upregulated specifically under saline conditions, whereas several genes important for growth and development, as well as circadian entrainment were specifically enriched in fish reared in freshwater. Routing of the circadian rhythm mediated by salinity changes could be the initial step in salinity acclimation and possibly migration in euryhaline fish species such as the Asian seabass.

Intestinal glycyl-L-phenylalanine and L-phenylalanine transport in a euryhaline teleost

1991 ◽  
Vol 260 (3) ◽  
pp. R563-R569 ◽  
Author(s):  
S. J. Reshkin ◽  
G. A. Ahearn
Keyword(s):  
Significant Contribution ◽  
Brush Border Membrane ◽  
Membrane Vesicles ◽  
Transport Mechanisms ◽  
Intestinal Brush Border Membrane ◽  
Overshoot Phenomenon ◽  
Independent Process ◽  
Euryhaline Teleost ◽  
Dipeptide Uptake ◽  
Phenylalanine Transport

The transport mechanisms for the dipeptide glycyl-L-phenylalanine (Gly-Phe) and L-phenylalanine (Phe) were characterized in fish intestinal brush-border membrane vesicles (BBMV). Gly-Phe was rapidly hydrolyzed only intravesicularly with almost total hydrolysis occurring even at 10 s. Dipeptide uptake was not stimulated by an inward gradient of Na, K, or H. Phe uptake was stimulated by an inward gradient of either Na or K but displayed an overshoot phenomenon only in the presence of an Na gradient. Kinetic analysis of the effect of substrate concentration on transport rate revealed that transport of both Gly-Phe and Phe occurred by a saturable process conforming to Michaelis-Menten kinetics. The Km for Gly-Phe was 9.8 +/- 3.5 mM, whereas that for Phe in the presence of Na or K, respectively, was 0.74 +/- 0.13 and 1.1 +/- 0.37 mM. Maximum uptake for Gly-Phe and for Phe in the presence of Na and K was 5.1, 0.9, and 0.4 nmol.mg and protein-1.5 s-1, respectively. Gly-Phe and Phe transport displayed different patterns of inhibition by dipeptides and amino acids. These results suggest that Gly-Phe and Phe are transported via different mechanisms, with Gly-Phe being hydrolyzed during a carrier-mediated, cation-independent process and Phe being transferred via a Na+ cotransport process similar to that described in mammals. During conditions of high luminal dipeptide concentrations, the Gly-Phe pathway may make a significant contribution to total Phe uptake.

Estrogen-related receptor γ2 controls NaCl uptake to maintain ionic homeostasis

2021 ◽  
Author(s):  
Shang-Wu Shih ◽  
Jia-Jiun Yan ◽  
Yi-Hsing Wang ◽  
Yi-Ling Tsou ◽  
Ling Chiu ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Body Fluid ◽  
Whole Body ◽  
Ionic Homeostasis ◽  
Ion Regulation ◽  
Expression Levels ◽  
Morpholino Knockdown ◽  
Oryzias Melastigma ◽  
Euryhaline Teleost

Estrogen-related receptors (ERRs) are known to function in mammalian kidney as key regulators of ion transport-related genes; however, a comprehensive understanding of the physiological functions of ERRs in vertebrate body fluid ionic homeostasis is still elusive. Here, we used medaka (Oryzias melastigma), a euryhaline teleost, to investigate how ERRs are involved in ion regulation. After transferring medaka from hypertonic seawater to hypotonic freshwater (FW), the mRNA expression levels of errγ2 were highly upregulated, suggesting that ERRγ2 may play a crucial role in ion uptake. In situ hybridization and immunofluorescence staining showed that errγ2 was specifically expressed in ionocytes, the cells responsible for Na+/Cl- transport. In normal FW, ERRγ2 morpholino knockdown caused reductions in the mRNA expression of Na+/Cl- cotransporter (NCC), the number of NCC ionocytes, Na+/Cl- influxes of ionocytes, and whole-body Na+/Cl- contents. In FW with low Na+ and low Cl-, the expression levels of mRNA for Na+/H+ exchanger 3 (NHE3) and NCC were both decreased in ERRγ2 morphants. Treating embryos with DY131, an agonist of ERRγ, increased the whole-body Na+/Cl- contents and ncc mRNA expression in ERRγ2 morphants. As such, medaka ERRγ2 may control Na+/Cl- uptake by regulating ncc and/or nhe3 mRNA expression and ionocyte number, and these regulatory actions may be subtly adjusted depending on internal and external ion concentrations. These findings not only provide new insights into the underpinning mechanism of actions of ERRs, but also enhance our understanding of their roles in body fluid ionic homeostasis for adaptation to changing environments during vertebrate evolution.

Liza aurata: Following different salinity acclimation

2008 ◽  
Vol 150 (3) ◽  
pp. S113
Author(s):  
S. Khodabandeh ◽  
M. Shahreyari Moghadam ◽  
B. Abtahi ◽  
A. Hosseinzadeh
Keyword(s):  
Salinity Acclimation ◽  
Liza Aurata

Benzocaine-induced stress in the euryhaline teleost, Centropomus parallelus and its implications for anesthesia protocols

2018 ◽  
Vol 226 ◽  
pp. 32-37 ◽  
Author(s):  
Natascha Wosnick ◽  
Fabiano Bendhack ◽  
Renata D. Leite ◽  
Rosana N. Morais ◽  
Carolina A. Freire
Keyword(s):  
Induced Stress ◽  
Euryhaline Teleost
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