Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 12 October 1990:
Vol. 250. no. 4978, pp. 285 - 288
DOI: 10.1126/science.2218533
Prev | Table of Contents | Next

Articles

Science, Vol 250, Issue 4978, 285-288
Copyright © 1990 by American Association for the Advancement of Science

articles

A magnesium current in Paramecium

RR Preston

Laboratory of Molecular Biology, University of Wisconsin-Madison 53706.

Recent reappraisals of the role of ionized magnesium in cell function suggest that many cells maintain intracellular free Mg2+ at low concentrations (0.1 to 0.7 mM) and that external agents can influence cell function via changes in intracellular Mg2+ concentration. Depolarization and hyperpolarization of voltage-clamped Paramecium elicited a Mg2(+)-specific current, IMg. Both Co2+ and Mn2+ were able to substitute for Mg2+ as charge carriers, but the resultant currents were reduced compared with Mg2+ currents. Intracellular free Mg2+ concentrations were estimated from the reversal potential of IMg to be about 0.39 mM. The IMg was inhibited when external Ca2+ was removed or a Ca2+ chelator was injected, suggesting that its activation was Ca2(+)-dependent.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Ion Channels in Microbes.
B. Martinac, Y. Saimi, and C. Kung (2008)
Physiol Rev 88, 1449-1490
   Abstract »    Full Text »    PDF »
Genetic dissection of attractant-induced conductances in Paramecium.
W. E. Bell, R. R. Preston, J. Yano, and J. L. Van Houten (2007)
J. Exp. Biol. 210, 357-365
   Abstract »    Full Text »    PDF »
An exchanger-like protein underlies the large Mg2+ current in Paramecium.
W. J. Haynes, C. Kung, Y. Saimi, and R. R. Preston (2002)
PNAS 99, 15717-15722
   Abstract »    Full Text »    PDF »
Isolation and Characterization of Magbane, a Magnesium-Lethal Mutant of Paramecium.
J. A. Hammond and R. R. Preston (2001)
Genetics 158, 1061-1069
   Abstract »    Full Text »    PDF »
Overexpression of the Saccharomyces cerevisiae Magnesium Transport System Confers Resistance to Aluminum Ion.
C. W. MacDiarmid and R. C. Gardner (1998)
J. Biol. Chem. 273, 1727-1732
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)