Tolerance and ultrastructural responses of branchial chloride cells to salinity changes in the euryhaline teleost Oreochromis mossambicus

1987 ◽  
Vol 94 (4) ◽  
pp. 643-649 ◽  
Author(s):  
P. P. Hwang
2002 ◽  
Vol 75 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Ching‐Feng Weng ◽  
Chia‐Chang Chiang ◽  
Hong‐Yi Gong ◽  
Mark Hung‐Chih Chen ◽  
Cliff Ji‐Fan Lin ◽  
...  

2015 ◽  
Vol 309 (10) ◽  
pp. R1251-R1263 ◽  
Author(s):  
Mayu Inokuchi ◽  
Jason P. Breves ◽  
Shunsuke Moriyama ◽  
Soichi Watanabe ◽  
Toyoji Kaneko ◽  
...  

This study characterized the local effects of extracellular osmolality and prolactin (PRL) on branchial ionoregulatory function of a euryhaline teleost, Mozambique tilapia ( Oreochromis mossambicus). First, gill filaments were dissected from freshwater (FW)-acclimated tilapia and incubated in four different osmolalities, 280, 330, 380, and 450 mosmol/kg H2O. The mRNA expression of Na+/K+-ATPase α1a (NKA α1a) and Na+/Cl− cotransporter (NCC) showed higher expression with decreasing media osmolalities, while Na+/K+/2Cl− cotransporter 1a (NKCC1a) and PRL receptor 2 (PRLR2) mRNA levels were upregulated by increases in media osmolality. We then incubated gill filaments in media containing ovine PRL (oPRL) and native tilapia PRLs (tPRL177 and tPRL188). oPRL and the two native tPRLs showed concentration-dependent effects on NCC, NKAα1a, and PRLR1 expression; Na+/H+ exchanger 3 (NHE3) expression was increased by 24 h of incubation with tPRLs. Immunohistochemical observation showed that oPRL and both tPRLs maintained a high density of NCC- and NKA-immunoreactive ionocytes in cultured filaments. Furthermore, we found that tPRL177 and tPRL188 differentially induce expression of these ion transporters, according to incubation time. Together, these results provide evidence that ionocytes of Mozambique tilapia may function as osmoreceptors, as well as directly respond to PRL to modulate branchial ionoregulatory functions.


2003 ◽  
Vol 284 (1) ◽  
pp. C233-C241 ◽  
Author(s):  
Li-Yih Lin ◽  
Chia-Chang Chiang ◽  
Hong-Yi Gong ◽  
Ching-Yi Cheng ◽  
Pung-Pung Hwang ◽  
...  

Although euryhaline teleosts can adapt to environmental fluctuation of salinity, their energy source for responding to changes in salinity and osmolarity remains unclear. This study examines the cellular localization of creatine kinase (CK) expression in branchia of tilapia ( Oreochromis mossambicus). Western blot analysis of muscle-type CK (MM form) revealed a high association with salinity changes, but BB and MB forms of CK in the gills of fish adapted to seawater did not change. With the use of immunocytochemistry, three CK isoforms (MM, MB, and BB) were localized in mitochondria-rich (MR) cells and other epithelial cells of tilapia gills. In addition, staining intensity of MM-form CK in MR cells increased after seawater transfer, whereas BB and MB forms did not significantly change. To our knowledge, this work presents the first evidence of CK expression in MR cells of tilapia gills, highlighting the potential role of CK in providing energy for ion transport.


1984 ◽  
Vol 62 (12) ◽  
pp. 2674-2677 ◽  
Author(s):  
Brian Harvey ◽  
R. Norman Kelley

Motility in Oreochromis mossambicus spermatozoa was determined in mannitol solutions of varying osmolality. The number of spermatozoa activated was maximal in distilled water and declined with increasing osmolality. Transfer of males from freshwater to dilute seawater (22‰) and full seawater (35‰) increased motility at any given osmolality within 2 days. Spermatozoa from fish held at three test salinities showed varying degrees of motility at the mean osmolality of undiluted milt (321 mosmol/kg). Spermatozoa were fertile in full seawater, although motility in this medium and in a mannitol solution of the same osmolality was only 0.2%. The involvement of a second factor modulating spermatozoan motility in O. mossambicus is proposed.


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