Intracellular pH regulation in mantle epithelial cells of the Pacific oyster, Crassostrea gigas
- PDF / 3,117,215 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 55 Downloads / 201 Views
ORIGINAL PAPER
Intracellular pH regulation in mantle epithelial cells of the Pacific oyster, Crassostrea gigas Kirti Ramesh1,2 · Marian Y. Hu3 · Frank Melzner1 · Markus Bleich3 · Nina Himmerkus3 Received: 18 November 2019 / Revised: 31 July 2020 / Accepted: 9 August 2020 © The Author(s) 2020
Abstract Shell formation and repair occurs under the control of mantle epithelial cells in bivalve molluscs. However, limited information is available on the precise acid–base regulatory machinery present within these cells, which are fundamental to calcification. Here, we isolate mantle epithelial cells from the Pacific oyster, Crassostrea gigas and utilise live cell imaging in combination with the fluorescent dye, BCECF-AM to study intracellular pH (pHi) regulation. To elucidate the involvement of various ion transport mechanisms, modified seawater solutions (low sodium, low bicarbonate) and specific inhibitors for acid–base proteins were used. Diminished pH recovery in the absence of Na+ and under inhibition of sodium/hydrogen exchangers (NHEs) implicate the involvement of a sodium dependent cellular proton extrusion mechanism. In addition, pH recovery was reduced under inhibition of carbonic anhydrases. These data provide the foundation for a better understanding of acid–base regulation underlying the physiology of calcification in bivalves. Keywords Mollusc · Calcification · Acid–base · Ion transport proteins
Introduction Shells of the Pacific oyster, Crassostrea gigas, a mollusc species with enormous economic and ecological value (Zhang et al. 2012) are characterized by the presence of two calcareous valves. In adult C. gigas molluscs, shell formation occurs under the control of the mantle tissue, where mantle epithelial cells take part in the transport of calcification substrates (Gong et al. 2008) (Ca2+ and H CO3−). Recently, Sillanpaa et al. (2018) reported that up to 60% of the Ca2+ transport in C. gigas mantle epithelia occurs via Communicated by Bernd Pelster. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00360-020-01303-3) contains supplementary material, which is available to authorized users. * Kirti Ramesh [email protected] 1
GEOMAR Helmholtz Centre for Ocean Research, Kiel 24105, Germany
2
Department of Biological & Environmental Sciences, Gothenburg University, Gothenburg, Sweden
3
Institute of Physiology, Christian Albrechts University Kiel, 24118 Kiel, Germany
the transcellular pathway. However, it is unknown at present by which pathways bivalve molluscs control the precipitation of the calcareous shell. Since proton production is a byproduct of mineral formation from the bicarbonate ( HCO3−) substrate (Zeebe and Wolf-Gladrow 2001), specific mechanisms have to be present in calcifying molluscs to minimize fluctuations in intracellular pH ( pHi). For calcification to take place, mantle epithelial cells would be responsible for generating and maintaining a highly regulated microenvironment. This makes intracellular pH hom
Data Loading...
