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Plant Physiol. 2003 Mar;131(3):1391-400.

A novel Cl- inward-rectifying current in the plasma membrane of the calcifying marine phytoplankton Coccolithus pelagicus.

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  • 1The Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom. arta@mba.ac.uk

Abstract

We investigated the membrane properties and dominant ionic conductances in the plasma membrane of the calcifying marine phytoplankton Coccolithus pelagicus using the patch-clamp technique. Whole-cell recordings obtained from decalcified cells revealed a dominant anion conductance in response to membrane hyperpolarization. Ion substitution showed that the anion channels were selective for Cl(-) and Br(-) over other anions, and the sensitivity to the stilbene derivative 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid, ethacrynic acid, and Zn(2+) revealed a pharmacological profile typical of many plant and animal anion channels. Voltage activation and kinetic characteristics of the C. pelagicus Cl(-) channel are consistent with a novel function in plants as the inward rectifier that tightly regulates membrane potential. Membrane depolarization gave rise to nonselective cation currents and in some cases evoked action potential currents. We propose that these major ion conductances play an essential role in membrane voltage regulation that relates to the unique transport physiology of these calcifying phytoplankton.

PMID:
12644688
[PubMed - indexed for MEDLINE]
PMCID:
PMC166898
Free PMC Article
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