Low salinity-induced alterations in epithelial ultrastructure, Na+/K+-ATPase immunolocalization and enzyme kinetic characteristics in the gills of the thinstripe hermit crab, Clibanarius vittatus (Anomura, Diogenidae)

Author(s)

Antunes, Claudia Doi ^{[1, 2]} ; Lucena, Malson Neilson ^[3] ; Garcon, Daniela Pereira ^[4] ; Leone, Francisco Assis ^[3] ; McNamara, John Campbell ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Biol, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Ctr Biol Marinha, Sao Sebastiao, SP - Brazil

^[3] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Quim, Ribeirao Preto, SP - Brazil

^[4] Univ Fed Triangulo Mineiro, Campus Univ Iturama, Iturama, MG - Brazil

• Document type: Journal article
• Source: JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY; v. 327, n. 6, p. 380-397, JUL 2017.
• Web of Science Citations: 2

Abstract

Fresh caught Clibanarius vittatus {[}SW, 31 parts per thousand salinity (S)] were acclimated to a dilute medium (15 parts per thousand S) for 10 days, employing silver staining to locate gill ion transporting tissue, immunofluorescence to localize the Na+/K+-ATPase alpha-subunit in the lamellae, and electron microscopy to portray ultrastructural changes in the gill epithelia. Na+/K+-ATPase activity was characterized kinetically in a gill microsomal fraction, including synergistic stimulation by NH4+ plus K+. Silver staining revealed that all 26 phyllobranchiate arthro-and pleurobranchiae participate in ion transport. Na+/K+-ATPase alpha-subunit staining was weak in SW crabs and distributed exclusively and irregularly within the intralamellar septal cells, particularly at the septal-pillar cell body junctions, and septal cell cytoplasm facing the hemolymph space. In 15 parts per thousand S crabs, alpha-subunit localization was intense, occupying the entire thickened septum. Pillar cells and flanges did not stain. Mitochondria and membrane foldings increased in the pillar cell flanges and intralamellar septal cells, greatly amplifying surface area. Only a single ATP binding site (V-M = 130.8 +/- 10.5 nmol min(-1) mg protein(-1); K-0.5 = 55.3 +/- 1.7 mu mol l(-1)) obeying Michaelis-Menten kinetics was disclosed. Na+/K+-ATPase activity was modulated by Mg2+, Na+, and NH4+, exhibiting site-site interactions; K+ modulation showed Michaelis-Menten kinetics. K+ plus NH4+ synergistically stimulated activity approximate to 1.7-fold. Ouabain inhibited total ATPase activity by approximate to 70% (K-I = 220-300 mu mol l(-1)), revealing phosphohydrolytic activities other than the Na+/K+-ATPase. Despite ample phylogenetic separation, the phyllobranchiate lamellae of the Anomura and Caridea share many ultrastructural features, that is, an intralamellar septum and opposed abutting pillar cells, similar Na+/K+-ATPase distribution, and comparable kinetic characteristics. These findings suggest either convergent evolution at the structural and biochemical levels, or preservation of traits present in a remote common ancestor. (AU)

• FAPESP's process: 13/22605-1 - Kinetic and molecular characterization of gill tissue (Na+,K+)-ATPase from Cardisoma guanhumi (Latreille)crab
• Grantee: Francisco de Assis Leone
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/17534-0 - Role of (Na,K)-ATPase in osmoregulation and excretion of ammonium ions in euryhaline crustaceans: identification and influence of FXYD2 on the regulation of gill (Na,K)-ATPase of the crab Callinectes danae
• Grantee: Francisco de Assis Leone
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/24252-9 - The (Na+,K+)-ATPase in osmoregulatory capacity in crab Ucides cordatus: biochemical and molecular view
• Grantee: Malson Neilson de Lucena
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 10/50188-8 - Decapod crustaceans: multi-disciplinary characterization of the sea biodiversity of the State of São Paulo (taxonomy, spermiotaxonomy, molecular biology and population dynamics)
• Grantee: Fernando Luis Medina Mantelatto
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants