Skip Navigation

Plant and Cell Physiology 2004 45(10):1434-1441; doi:10.1093/pcp/pch164
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrow Search for citing articles in:
ISI Web of Science (3)
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Obata, T.
Right arrow Articles by Shiraiwa, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Obata, T.
Right arrow Articles by Shiraiwa, Y.
Agricola
Right arrow Articles by Obata, T.
Right arrow Articles by Shiraiwa, Y.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© 2004 Oxford University Press

Bioconcentration Mechanism of Selenium by a Coccolithophorid, Emiliania huxleyi

Toshihiro Obata, Hiroya Araie and Yoshihiro Shiraiwa1

Institute of Biological Sciences, University of Tsukuba, Tsukuba, 305-8572 Japan

We investigated the uptake and bioconcentration of the essential element selenium by a coccolithophorid, Emiliania huxleyi, using [75Se]selenite. The time course of 75Se uptake showed a biphasic pattern, namely a primary phase and a subsequent secondary phase. The primary and secondary phases are due to a rapid selenite uptake process that attained a stationary level within 2 min and a slow Se-accumulation process that continued at a constant rate for 4 h or longer, respectively. Kinetic analysis revealed that the selenite uptake process consists of two components, one saturable and one linearly related to substrate concentration. The Km of the saturable component was 29.8 nM selenite; the uptake activity of this component was suppressed by inhibitors of ATP biogenesis, suggesting that selenite uptake is driven by a high-affinity, active transport system. During a 6-h incubation of cells with [75Se]selenite, 70% of the intracellular 75Se was incorporated into low-molecular-mass compounds (LMCs), and 17% was incorporated into proteins, but [75Se]selenite was barely detectable. A pulse–chase experiment demonstrated that the 75Se that had accumulated in LMCs was transferred into proteins. When the syntheses of amino acids and proteins were each separately inhibited, 75Se incorporation into LMCs and proteins was decreased. These results suggest that E. huxleyi rapidly absorbs selenite, filling a small intracellular pool. Then, Se-containing LMCs are immediately synthesized from the selenite, creating a pool of LMCs that are then metabolized to selenoproteins.

1 Corresponding author: E-mail, emilhux{at}biol.tsukuba.ac.jp; Fax, +81-29-853-6614.


Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J. Biol. Chem.Home page
H. Araie, I. Suzuki, and Y. Shiraiwa
Identification and Characterization of a Selenoprotein, Thioredoxin Reductase, in a Unicellular Marine Haptophyte Alga, Emiliania huxleyi
J. Biol. Chem., December 19, 2008; 283(51): 35329 - 35336.
[Abstract] [Full Text] [PDF]

Home page
 J. Biol. Chem.Home page
T. Obata and Y. Shiraiwa
A Novel Eukaryotic Selenoprotein in the Haptophyte Alga Emiliania huxleyi
J. Biol. Chem., May 6, 2005; 280(18): 18462 - 18468.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.