|
|
|
|
 |
|||
|
|||
Secretory organelles of Paramecium cells (trichocysts) are not remarkably acidic compartments
CJ Lumpert, R Glas-Albrecht, E Eisenmann and H Plattner
Faculty of Biology, University of Konstanz, Federal Republic of Germany.
Acridine orange (AO) trapping in conjunction with fluorescence microscopy was applied to Paramecium cells. Trichocysts were not labeled when analyzed with an image intensification system (as opposed to a lysosomal population). Only with increasing intensity of ultraviolet light (UV) did trichocysts (and to some extent the cytosol) exhibit orange fluorescence, both effects being paralleled by increasing cell damage. Therefore, in comparison with the reported cytosolic pH (6.8), trichocysts cannot be considered as essentially acidic compartments. This is supported by experiments in vitro, using isolated cortex fragments or isolated fractions of membrane-bounded trichocysts (greater than or equal to 90% non-leaky). Again, during UV illumination orange fluorescence was observed even in the absence of ATP and Mg2+. Furthermore, this AO fluorescence and the condensation state of trichocyst contents were not affected by NH3 or by any of the widely differing ion- and H(+)-exchange inhibitors or ionophores tested. Decondensation of trichocyst contents occurred only when Ca2+ ionophore A23187 or X537A was incorporated into trichocyst membranes and when Ca2+ was then added. In this case all trichocysts partially decondensed within their intact membranes. We conclude that AO might be trapped in trichocysts by the abundant acidic secretory components during observation with UV light, rather than by acidic luminal pH.
Volume 40,
Issue 1,
pp. 153-160,
01/01/1992
Copyright © 1992 by The Histochemical Society
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Wassmer, R. Kissmehl, J. Cohen, and H. Plattner Seventeen a-Subunit Isoforms of Paramecium V-ATPase Provide High Specialization in Localization and Function Mol. Biol. Cell, February 1, 2006; 17(2): 917 - 930. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Wassmer, M. Froissard, H. Plattner, R. Kissmehl, and J. Cohen The vacuolar proton-ATPase plays a major role in several membrane-bounded organelles in Paramecium J. Cell Sci., July 1, 2005; 118(13): 2813 - 2825. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W. Verbsky and A. P. Turkewitz Proteolytic Processing and Ca2+-binding Activity of Dense-Core Vesicle Polypeptides in Tetrahymena Mol. Biol. Cell, February 1, 1998; 9(2): 497 - 511. [Abstract] [Full Text]
|
|
|
|
|
|
S. J. Shih and D. L. Nelson Proteolytic processing of secretory proteins in Paramecium: immunological and biochemical characterization of the precursors of trichocyst matrix proteins J. Cell Sci., October 1, 1992; 103(2): 349 - 361. [Abstract] [PDF]
|
|
| Guidelines | Subscriptions | About | exPRESS - Current - Archive | Business Information | Contact |