Calcium transport in gill cells of Ucides cordatus, a mangrove crab living in variable salinity environments

Author(s)

Leite, V. P. ^[1] ; Zanotto, F. P. ^[2]

Affiliation

^[1] Univ Fed Sao Paulo UNIFESP, Dept Renal Physiol, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Dept Physiol, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY; v. 166, n. 2, p. 370-374, OCT 2013.
• Web of Science Citations: 6

Abstract

Crustaceans show discontinuous growth and have been used as a model system for studying cellular mechanisms of calcium transport, which is the main mineral found in their exoskeleton. Ucides cordatus, a mangrove crab, is naturally exposed to fluctuations in calcium and salinity. To study calcium transport in this species during isosmotic conditions, dissociated gill cells were marked with fluo-3 and intracellular Ca2+ change was followed by adding extracellular Ca2+ as CaCl2 (0, 0.1, 0.25, 0.50, 1.0 and 5 mM), together with different inhibitors. For control gill cells, Ca2+ transport followed Michaelis-Menten kinetics with V-max = 0.137 +/- 0.001 Delta Ca(2+)i (mu M x 22.10(4) cells(-1) x 180 s(-1); N = 4; r(2) = 0.99); K-m = 0.989 +/- 0.027 mM. The use of different inhibitors for gill cells showed that amiloride (Na+/Ca2+ exchange inhibitor) inhibited 80% of Ca2+ transport in gill cells (V-max). KB-R, an inhibitor of Ca influx in vertebrates, similarly caused a decrease in Ca2+ transport and verapamil (Ca2+ channel inhibitor) had no effect on Ca2+ transport, while nifedipine (another Ca2+ channel inhibitor) caused a 20% decrease in Ca2+ affinity compared to control values. Ouabain, on the other hand, caused no change in Ca2+ transport while vanadate increased the concentration of intracellular calcium through inhibition of Ca2+ efflux probably through the plasma membrane Ca2+-ATPase. Results show that transport kinetics for Ca2+ in these crabs under isosmotic conditions is lower compared to a hyper-regulator freshwater crab Dilocarcinus pagei studied earlier using fluorescent Ca2+ probes. These kinds of studies will help understanding the comparative mechanisms underlying the evolution of Ca transport in crabs living in different environments. (C) 2013 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 09/15546-3 - Characterization of cadmium transport and its interaction with calcium on epithelial cells of Ucides cordatus, a mangrove crab
• Grantee: Flavia Pinheiro Zanotto
• Support Opportunities: Regular Research Grants