Ion-motive ATPases and active, transbranchial NaCl uptake in the red freshwater crab,Dilocarcinus pagei(Decapoda,Trichodactylidae)
| Autor: | David W. Towle, Dirk Weihrauch, John Campbell McNamara, Horst Onken |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Gills
Gill Vacuolar Proton-Translocating ATPases DNA Complementary animal structures Brachyura Physiology ATPase Molecular Sequence Data Biological Transport Active Fresh Water Sodium Chloride Aquatic Science Epithelium Ouabain Species Specificity medicine Animals Amino Acid Sequence RNA Messenger Molecular Biology Phylogeny Ecology Evolution Behavior and Systematics DNA Primers Base Sequence biology Ussing chamber Reverse Transcriptase Polymerase Chain Reaction Decapoda fungi Sequence Analysis DNA Anatomy biology.organism_classification Electrophysiology medicine.anatomical_structure Ion pump Insect Science Biophysics biology.protein Animal Science and Zoology Sodium-Potassium-Exchanging ATPase Sequence Alignment Brazil Freshwater crab medicine.drug |
| Zdroj: | Journal of Experimental Biology. 207:4623-4631 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.01333 |
| Popis: | SUMMARYThe present investigation examined the microanatomy and mRNA expression and activity of ion-motive ATPases, in anterior and posterior gills of a South American, true freshwater crab, Dilocarcinus pagei. Like diadromous crabs, the anterior gills of this hololimnetic trichodactylid exhibit a highly attenuated (2–5 μm), symmetrical epithelium on both lamellar surfaces. In sharp contrast, the posterior gill lamellar epithelia are markedly asymmetrical. Their proximal side consists of thick (18–20μm) cells, displaying features typical of a transporting epithelium, while the distal epithelium is thin (3–10 μm) and formed entirely by apical pillar cell flanges. Both anterior and posterior gills express Na+/K+- and V-ATPases. Phylogenetic analysis of partial cDNA sequences for the Na+/K+-ATPase α-subunit and V-ATPase B-subunit among various crab species confirmed the previous classification and grouping of D. pagei based on morphological criteria. Semi-quantitative RT-PCR clearly showed that mRNA for both ion pump subunits is more intensely expressed in posterior gills. Na+/K+-ATPase activity in the posterior gills was nearly fourfold that of anterior gills, while V-ATPase and F-ATPase activities did not differ. A negative short-circuit current (Isc) was measured using the distal side of split, posterior gill lamellae, mounted in a modified Ussing chamber and perfused symmetrically with identical hemolymph-like salines. Although hemolymph-side ouabain did not affect this current, concanamycin significantly reduced Isc without altering preparation conductance, suggesting V-ATPase-driven Cl– absorption on the distal side of the posterior gill lamellae, as known to occur in diadromous crabs adapted to freshwater. These findings suggest that active Na+ uptake predominates across the thick proximal epithelium, and Cl– uptake across the thin,distal epithelium of the posterior gill lamellae. |
| Databáze: | OpenAIRE |
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