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A kinetic characterization of the gill V(H+)-ATPase from two hololimnetic populations of the Amazon River shrimp Macrobrachium amazonicum.
- Source :
-
Comparative Biochemistry & Physiology - Part B: Biochemistry & Molecular Biology . Oct2023, Vol. 268, pN.PAG-N.PAG. 1p. - Publication Year :
- 2023
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Abstract
- This 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. [Display omitted] • V(H+)-ATPase activity is ≈60% greater in the Tietê than Grande River shrimp population. • ATP hydrolysis by the V(H+)-ATPase follows Michaelian kinetics in both populations. • 25% of V(H+)-ATPase activity occurs in sealed microsomes in Grande River shrimps. • In fresh water, the V(H+)-ATPase is immunolocalized to the apical pillar cell flanges. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10964959
- Volume :
- 268
- Database :
- Academic Search Index
- Journal :
- Comparative Biochemistry & Physiology - Part B: Biochemistry & Molecular Biology
- Publication Type :
- Academic Journal
- Accession number :
- 169876558
- Full Text :
- https://doi.org/10.1016/j.cbpb.2023.110880