A kinetic characterization of the gill V(H < sup > + < /sup > )-ATPase from two hololimnetic populations of the Amazon River shrimp Macrobrachium amazonicum

Comp Biochem Physiol B Biochem Mol Biol. 2023 Jul 28:110880. doi: 10.1016/j.cbpb.2023.110880. Online ahead of print.ABSTRACTThis investigation examines the kinetic characteristics and effect of acclimation to a brackish medium (21 ‰S) on gill V(H+)-ATPase activity in two hololimnetic populations of M. amazonicum. We also investigate the cellular immunolocalization of the enzyme. Immunofluorescence findings demonstrate that the V(H+)-ATPase c-subunit is distributed in the apical pillar cells of shrimps in fresh water but is absent after acclimation to 21 ‰S for 10 days. V(H+)-ATPase activity from the Tietê River population is ≈50% greater than the Grande River population, comparable to a wild population from the Santa Elisa Reservoir, but is 2-fold less than in cultivated shrimps. V(H+)-ATPase activity in the Tietê and the Grande River shrimps is abolished after 21 ‰S acclimation. The apparent affinities of the V(H+)-ATPase for ATP (0.27 ± 0.04 and 0.16 ± 0.03 mmol L-1, respectively) and Mg2+ (0.28 ± 0.05 and 0.14 ± 0.02 mmol L-1, respectively) are similar in both populations. The absence of V(H+)-ATPase activity in salinity-acclimated shrimps and its apical distribution in shrimps in fresh water underpins the importance of the crustacean V(H+)-ATPase for ion uptake in fresh water.PMID:37517460 | DOI:10.1016/j.cbpb.2023.110880
Source: Comparative biochemistry and physiology. Part B, Biochemistry and molecular biology. - Category: Biochemistry Authors: Source Type: research