Osmotic and ionic regulation, and kinetic characteristics of a posterior gill (Na+, K+)-ATPase from the blue crab Callinectes danae on acclimation to salinity challenge

Author(s)

Garcon, Daniela P. ^[1] ; Leone, Francisco A. ^[2] ; Faleiros, Rogerio O. ^[3] ; Pinto, Marcelo R. ^[4] ; Moraes, Cintya M. ^[5] ; Fabri, Leonardo M. ^[5] ; Antunes, Claudia D. ^[6] ; McNamara, John Campbell ^{[7, 6]}

Affiliation

^[1] Univ Fed Triangulo Mineiro, Campus Univ Iturama, Iturama, MG - Brazil

^[2] Univ Sao Paulo, Dept Quim, Fac Filosofia Ciencias & Letras Ribeirao Preto, Ribeirao Preto, SP - Brazil

^[3] Univ Fed Espirito Santo, Dept Ciencias Agr & Biol, Sao Mateus, ES - Brazil

^[4] Univ Uberaba, Lab Biopatol & Biol Mol, Uberaba, MG - Brazil

^[5] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Bioquim & Imunol, Ribeirao Preto, SP - Brazil

^[6] Univ Sao Paulo, Dept Biol, Fac Filosofia Ciencias & Letras Ribeirao Preto, Ave Bandeirantes 3900, BR-14040901 Ribeirao Preto, SP - Brazil

^[7] Univ Sao Paulo, Ctr Biol Marinha, Sao Sebastiao, SP - Brazil

• Document type: Journal article
• Source: Marine Biology; v. 168, n. 6 JUN 2021.
• Web of Science Citations: 0

Abstract

Salt tolerance reflects ecophysiological adaptation, and the wide-ranging distribution of the Brachyura mirrors their ability to adjust body fluid concentrations. The gill (Na+, K+)-ATPase underpins such hyper/hypo-regulatory mechanisms. We evaluate osmotic and chloride regulation in Callinectes danae after 10 days acclimation to a wide salinity range (5-50 parts per thousand S), accompanying alterations in hemolymph osmolality and {[}Cl-] during hypo- (15 parts per thousand S) or hyper- (45 parts per thousand S) osmotic challenge. Further, we investigate posterior gill (Na+, K+)-ATPase kinetics, alpha-subunit immunolocalization and its mRNA and protein expression (15, 30 and 40 or 45 parts per thousand S). The crab is a moderate, asymmetrical hyper/hypo-osmoregulator but is a strong, asymmetrical hyper/hypo-chloride regulator. Hyper-regulation at low salinity is sustained by a threefold increase in (Na+, K+)-ATPase activity, a 3.5-fold increase in alpha-subunit mRNA expression and 1.6-fold increase in protein expression. alpha-Subunit signal is highest in 15 parts per thousand S-acclimated crabs, and is uniformly distributed throughout the ionocytes and pillar cells. Activity in 30- and 40% S-acclimated crabs is similar. Affinity for ATP and Na+ increases on high salinity acclimation but decreases for ouabain. K+ apparent affinity is independent of salinity, while that for Mg2+ decreases and for NH4+ increases with increasing salinity. A high-affinity ATP-binding site disappears on acclimation at any salinity. FOF1- and Na+- or K+-ATPase activities decrease with increased salinity. Hemolymph chloride hypo-regulation depends little on gill (Na+, K+)-ATPase activity. Hyper-, and hypo-osmotic and ionic regulatory capabilities in C. danae are intricate physiological processes underpinned by multifarious gill (Na+, K+)-ATPase kinetics and altered mRNA and protein expressions. (AU)

• FAPESP's process: 15/00131-3 - Chloride secretion by the gill epithelium of shrimps and crabs from different osmotic niches: a physiological and molecular investigation of the Na+-K+-2Cl- symporter
• Grantee: John Campbell McNamara
• Support Opportunities: Regular Research Grants
• FAPESP's process: 07/04870-9 - Adaptive physiological strategies in the Crustacea: the invasion of fresh water and the molecular and structural bases of osmoregulation
• Grantee: John Campbell McNamara
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/25336-0 - Comparative biochemical study of gill (Na+, K +)- ATPase of Macrobrachium amazonicum (Heller, 1862) inhabitant of coastal and continental regions
• Grantee: Francisco de Assis Leone
• Support Opportunities: Regular Research Grants