scholarly journals Adaptation of the carbamoyl-phosphate synthetase enzyme in an extremophile fish

2020 ◽  
Vol 7 (10) ◽  
pp. 201200
Author(s):  
Lewis J. White ◽  
Gemma Sutton ◽  
Asilatu Shechonge ◽  
Julia J. Day ◽  
Kanchon K. Dasmahapatra ◽  
...  

Tetrapods and fish have adapted distinct carbamoyl-phosphate synthase (CPS) enzymes to initiate the ornithine urea cycle during the detoxification of nitrogenous wastes. We report evidence that in the ureotelic subgenus of extremophile fish Oreochromis Alcolapia , CPS III has undergone convergent evolution and adapted its substrate affinity to ammonia, which is typical of terrestrial vertebrate CPS I. Unusually, unlike in other vertebrates, the expression of CPS III in Alcolapia is localized to the skeletal muscle and is activated in the myogenic lineage during early embryonic development with expression remaining in mature fish. We propose that adaptation in Alcolapia included both convergent evolution of CPS function to that of terrestrial vertebrates, as well as changes in development mechanisms redirecting CPS III gene expression to the skeletal muscle.

Hepatology ◽  
1999 ◽  
Vol 29 (1) ◽  
pp. 181-185 ◽  
Author(s):  
J. Paul Schofield ◽  
J. Paul Schofield ◽  
Timothy M. Cox ◽  
C. Thomas Caskey ◽  
Maki Wakamiya

Cell ◽  
2009 ◽  
Vol 137 (3) ◽  
pp. 560-570 ◽  
Author(s):  
Takashi Nakagawa ◽  
David J. Lomb ◽  
Marcia C. Haigis ◽  
Leonard Guarente

2000 ◽  
Vol 203 (24) ◽  
pp. 3703-3715 ◽  
Author(s):  
K. Iwata ◽  
M. Kajimura ◽  
T. Sakamoto

To examine the transition to ureogenesis, the gobiid fish Mugilogobius abei was immersed in 2 mmol l(−)(1) NH(4)HCO(3) or a (15)N-labelled ammonia solution [1 mmol l(−)(1) ((15)NH(4))(2)SO(4), pH 8.0] for 4–8 days. When exposed to 2 mmol l(−)(1) NH(4)HCO(3) or (15)N-labelled ammonia solution for 4 days, the rate of urea excretion increased to seven times that of the control (in 20 % synthetic sea water) and remained at this level for 4 days. The proportion of nitrogen excreted as urea reached 62 % of total nitrogen excretion (ammonia-N + urea-N). (15)N-enrichment of the amide-N in glutamine in the tissues of fish exposed to (15)N-labelled ammonia was virtually the same as that of ammonia-N: i.e. approximately twice that of urea-N in the excreta and the tissues. Glutamine contents and glutamine synthetase activities in the liver and muscle increased greatly following exposure to ammonia. Urea and citrulline contents in the muscle and whole body of the exposed fish increased significantly, whereas uric acid contents remained unchanged. Carbamoyl phosphate synthetase III (CPSase III) mRNA expression and CPSase III activity were detected in the muscle, skin and gill, but levels were negligible in the liver. Furthermore, all other ornithine-urea cycle (O-UC) enzymes were also detected in muscle, skin and gill. Thus, M. abei clearly shows the transition from ammoniotely to ureotely under ammonia-loading condition and is able to produce urea mainly via the O-UC operating in multiple non-hepatic tissues as a means for ammonia detoxification.


1985 ◽  
Vol 225 (1) ◽  
pp. 271-274 ◽  
Author(s):  
A Husson ◽  
M Bouazza ◽  
C Buquet ◽  
R Vaillant

The activity changes of the urea-cycle enzymes were monitored in cultured foetal hepatocytes after dexamethasone and insulin treatments. Addition of dexamethasone induced the development of carbamoyl-phosphate synthetase, argininosuccinate synthetase, argininosuccinase and arginase activities as soon as day 16.5 of gestation. When insulin was added together with dexamethasone, it markedly inhibited the steroid-induced increase in carbamoyl-phosphate synthetase, argininosuccinate synthetase and argininosuccinase activities.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
David Sabater ◽  
Silvia Agnelli ◽  
Sofía Arriarán ◽  
José-Antonio Fernández-López ◽  
María del Mar Romero ◽  
...  

Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higherNOx; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite.NOxand creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability.


2021 ◽  
Vol 8 ◽  
pp. 2329048X2098517
Author(s):  
Meaghan McGowan ◽  
Carlos Ferreira ◽  
Matthew Whitehead ◽  
Sudeepta K. Basu ◽  
Taeun Chang ◽  
...  

Neonatal-onset urea cycle disorders (UCDs) may result in hyperammonemic (HA) encephalopathy presenting with several neurologic sequelae including seizures, coma, and death. However, no recommendations are given in how and when neurodiagnostic studies should be used to screen or assess for these neurologic complications. We present a case of carbamoyl phosphate synthetase 1 (CPS1) deficiency in a newborn female in which electroencephalogram monitoring to assess encephalopathy and seizures, and magnetic resonance imaging measurements of brain metabolites were used to guide care during her hyperammonemic crisis. Her neurologic course and response to treatment characterizes the significant neurologic impact of HA encephalopathy. Our group herein proposes a clinical neurodiagnostic pathway for managing acute HA encephalopathy.


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