Studies on the Color-Change Mechanism in a Fresh-Water Teleost, Nandus nandus (Ham.). II. Hormonal Control

1978 ◽  
Vol 26 (5) ◽  
pp. 261-269
Author(s):  
A.K. Jain ◽  
H.N. Bhargava
Keyword(s):  
Fresh Water ◽  
Color Change ◽  
Hormonal Control ◽  
Change Mechanism ◽  
Fresh Water Teleost

Adaptations to a terrestrial existence in the robber crab Birgus latro L. IX. Hormonal control of post-renal urine reprocessing and salt balance in the branchial chamber

2000 ◽  
Vol 203 (2) ◽  
pp. 389-396 ◽  
Author(s):  
S. Morris ◽  
P. Greenaway ◽  
A.M. Adamczewska ◽  
M.D. Ahern
Keyword(s):  
Cyclic Amp ◽  
Ion Transport ◽  
Fresh Water ◽  
Sea Water ◽  
Inhibitory Effect ◽  
Hormonal Control ◽  
Uptake System ◽  
Dietary Salt ◽  
Artificial Urine ◽  
Brachyuran Crabs

The terrestrial robber crab Birgus latro L. regulates the composition of its final excretory product (termed P) depending on the availability of dietary salt by reabsorbing ions from urine passed over the gills. Laboratory and field-based studies investigated the nature of the mechanisms of control of this branchial ion uptake. B. latro were prepared such that their branchial chambers could be perfused with artificial urine, and the rate of ion transport from the artificial urine was determined. For B. latro acclimated to drinking fresh water, the rates of Na(+) and Cl(−) uptake were more than four times those of crabs drinking 70 % sea water. Crabs were injected with either saline carrier or the same solution containing either dopamine or dibutyryl cyclic AMP (db-cAMP) (final concentration 8.7×10(−)(7)mol l(−)(1)haemolymph). Dopamine and db-cAMP inhibited Na(+) and Cl(−) uptake in animals acclimated to fresh water and markedly reduced their gill Na(+)/K(+)-ATPase activity. Dopamine stimulated the production of cyclic AMP within the branchial epithelial cells. Dopamine, released from the pericardial organs, acts as a primary messenger, and cyclic AMP acts as a second messenger most likely promoting phosphorylation of membrane proteins. In contrast to aquatic brachyuran crabs, ion transport in B. latro, an anomuran, is controlled via an inhibitory effect. Terrestrial crabs normally have access to fresh water and must salvage salt from their urine, and a mechanism to down-regulate a normally active uptake system seems more appropriate to their ecology. Whether the control is stimulatory or inhibitory in the various air-breathing crabs may depend on the osmoregulatory abilities of their aquatic ancestors, but in either case has significant implications for the evolution of crustaceans to life on land. Further work must establish whether terrestrial brachyuran crabs are similar to B. latro and whether this crab is unique amongst the anomuran crabs.

Sex steroids exert a suppressive effect on innate and cell mediated immune responses in fresh water teleost, Channa punctatus

2019 ◽  
Vol 100 ◽  
pp. 103415 ◽  
Author(s):  
Sunita Patel ◽  
Meghmala Choudhary ◽  
Rakesh Kumar Chandra ◽  
Ajay Kumar Bhardwaj ◽  
Manish Kumar Tripathi
Keyword(s):  
Immune Responses ◽  
Fresh Water ◽  
Sex Steroids ◽  
Suppressive Effect ◽  
Channa Punctatus ◽  
Fresh Water Teleost
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