Short- and long-term, salinity-induced modulation of V-ATPase activity in the posterior gills of the true freshwater crab, Dilocarcinus pagei (Brachyura, Trichodactylidae).

Autor: Firmino KC; Departamento de Química, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil., Faleiros RO, Masui DC, McNamara JC, Furriel RP
Jazyk: angličtina
Zdroj: Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology [Comp Biochem Physiol B Biochem Mol Biol] 2011 Sep; Vol. 160 (1), pp. 24-31. Date of Electronic Publication: 2011 May 16.
DOI: 10.1016/j.cbpb.2011.05.002
Abstrakt: To better understand the biochemical mechanisms underlying anisosmotic extracellular regulation in the freshwater Brachyura, we kinetically characterized the V-ATPase from the posterior gills of Dilocarcinus pagei, acclimated for 10days to salinities up to 21‰. Specific activity was highest in fresh water (26.5±2.1U mg(-1)), decreasing in 5‰ to 21‰, attaining 3-fold less at 15‰. Apparent affinities for ATP and Mg(2+) respectively increased 3.2- and 2-fold at 10‰, suggesting expression of different isoenzymes. In a 240-h time-course study of exposure to 21‰, maximum specific activity decreased 2.5- to 4-fold within 1 to 24h while apparent affinities for ATP and Mg(2+) respectively increased by 12-fold within 24h and 2.4-fold after 1h, unchanged thereafter. K(I) for bafilomycin A(1) decreased 150-fold after 1h, remaining constant up to 120h. This is the first kinetic analysis of V-ATPase specific activity in crustacean gills during salinity acclimation. Our findings indicate active gill Cl(-) uptake by D. pagei in fresh water, and short- and long-term down-regulation of V-ATPase-driven ion uptake processes during salinity exposure, aiding in comprehension of the biochemical adaptations underpinning the establishment of the Brachyura in fresh water.
(Copyright © 2011 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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