QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online November 10, 2003

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Iwamoto, M. Articles by Naitoh, Y. Search for Related Content PubMed PubMed Citation Articles by Iwamoto, M. Articles by Naitoh, Y. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB CALCIUM COMPOUNDS CALCIUM, ELEMENTAL Medline Plus Health Information Fluid and Electrolyte Balance Social Bookmarking                         What's this?

The Journal of Experimental Biology 206, 4467-4473 (2003)
doi: 10.1242/jeb.00696

Hypo-osmotic or Ca²⁺-rich external conditions trigger extra contractile vacuole complex generation in Paramecium multimicronucleatum

Masaaki Iwamoto, Richard D. Allen and Yutaka Naitoh^*

Pacific Biomedical Research Center, Snyder Hall 306, University of Hawaii at Manoa, 2538 The Mall, Honolulu, HI 96822, USA

^* Author for correspondence (e-mail: naitoh{at}pbrc.hawaii.edu)

Accepted 1 September 2003

The freshwater ciliated protozoan, Paramecium multimicronucleatum, usually possesses two contractile vacuole complexes (CVCs). The number of CVCs in a single cell, however, may vary from 1 to 7. We found that the number of cells that have more than two CVCs increased after the cells were exposed to a hypo-osmotic or a high Ca²⁺ condition. It is assumed that the biological significance of this increase in the number of CVCs is to enhance the cell's ability to eliminate excess water or Ca²⁺ from the cytosol. An extra CVC was either generated de novo in the posterior region of the cell or, when in the anterior region, by binary fission of the anterior CVC. Generation of these extra CVCs was not inhibited by aphidicolin, a potent inhibitor of DNA synthesis in the micronuclei of Paramecium, even though normal duplication of the CVC that accompanies normal cell division was completely inhibited by this inhibitor. These results suggest that generation of extra CVCs is controlled by a hypothetical regulatory mechanism that is activated either by a hypo-osmotic or by a Ca²⁺-rich condition and that differs from the regulatory mechanism that governs normal CVC duplication during cell division.

Key words: contractile vacuole complex, osmoregulation, Ca²⁺ regulation, organelle biogenesis, Paramecium multimicronucleatum

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				A. J. Stemm-Wolf, G. Morgan, T. H. Giddings Jr., E. A. White, R. Marchione, H. B. McDonald, and M. Winey Basal Body Duplication and Maintenance Require One Member of the Tetrahymena thermophila Centrin Gene Family Mol. Biol. Cell, August 1, 2005; 16(8): 3606 - 3619. [Abstract] [Full Text] [PDF]