Data/hora: 05/06/2024 19:12:53

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Different biochemical strategies of two Neotropical fish to cope with the impairment of nitrogen excretion during air exposure	
Autores: 	Polez,V.L.P.; Moraes,G.; Santos Neto,C.	
Data: 	2003-02-01	
Ano: 	2003	
Palavras-chave: 	Hoplias malabaricus; Hoplerythrinus unitaeniatus; Fish; Urea cycle enzymes; Biochemical adaptation; Air exposure.	
Resumo: 	The exposure of fish to air is normally expected to interfere with the nitrogen excretion process. Hoplias malabaricus and Hoplerythrinus unitaeniatus, two teleost species, display distinct behaviors in response to decreases in natural reservoir water levels, although they may employ similar biochemical strategies. To investigate this point, plasma levels of ammonia, urea, uric acid, and the two urea cycle enzymes, ornithine carbamoyl transferase (OCT) and arginase (ARG), as well as glutamine synthetase (GS) were determined for both species after exposure to air. Plasma ammonia increased gradually during exposure to air, but only H. malabaricus showed increased concentrations of urea. Plasma uric acid remained very low in both fish. Enzymatic activities (mean ± SD, µmol min-1 g protein-1) of H. malabaricus showed significant increases (P&lt;0.05, N = 6) in OCT from 0.84 ± 0.05 to 1.42 ± 0.03, in ARG from 8.07 ± 0.47 to 9.97 ± 0.53 and in GS from 1.15 ± 0.03 to 2.39 ± 0.04. The OCT and ARG enzymes remained constant in H. unitaeniatus (N = 6), but GS increased from 1.49 ± 0.02 to 2.06 ± 0.03. Although these species are very closely related and share the same environment, their biochemical strategies in response to exposure to air or to increased plasma ammonia are different.	
Tipo: 	Info:eu-repo/semantics/article	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000200017	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2003000200017	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.36 n.2 2003	
Fonte: 	info:eu-repo/semantics/openAccess