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Subcellular calcium localization in Toxoplasma gondii by electron microscopy and by X‐ray and electron energy loss spectroscopies
Author(s) -
Bonhomme A.,
Pingret L.,
Bonhomme P.,
Michel J.,
Balossier G.,
Lhotel M.,
Pluot M.,
Pi J. M.
Publication year - 1993
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.1070250403
Subject(s) - egta , vacuole , toxoplasma gondii , ultrastructure , calcium , transmission electron microscopy , biophysics , electron microscope , chemistry , nuclear chemistry , cytoplasm , biology , materials science , biochemistry , anatomy , nanotechnology , antibody , immunology , optics , physics , organic chemistry
The localization of calcium in Toxoplasma gondii tachyzoites was studied at the ultrastructural level, with a cytochemical pyroantimonate precipitation method (PA) and controlled by EGTA chelating and EDX and EELS microanalyses. Appropriate conditions for material preparation, fixation and embedding, were defined. The proportion of precipitates that were either free or inside vacuoles and their distribution inside Toxoplasma appeared to be PA dose‐dependent. Precipitation mainly occurred in the anterior pole of the Epon‐embedded tachyzoites. EDX and EELS analyses showed that out of 30 PA precipitates inside tachyzoites, 78% contained Ca. In Melamine sections, 96% of the tachyzoites had intracellular precipitates and the membrane complex was stained; 25% of the tachyzoites inside host cells contained PA‐Ca precipitates, but most of them were retained in the reticular network of the parasitophorous vacuole. Melamine embedding appeared to improve the preservation of calcium pyroantimonate precipitates. © 1993 Wiley‐Liss, Inc.