학술논문
Potassium permanganate is an excellent alternative to osmium tetroxide in freeze-substitution.
Document Type
Article
Source
Subject
*LIPID analysis
*FREEZING
*MOLECULAR diagnosis
*STAINS & staining (Microscopy)
*CHEMICAL reagents
*POTASSIUM compounds
*ELECTRON microscopy
*OXIDES
*COLLECTION & preservation of biological specimens
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Language
ISSN
0948-6143
Abstract
High-pressure freezing followed by freeze-substitution is a valuable method for ultrastructural analyses of resin-embedded biological samples. The visualization of lipid membranes is one of the most critical aspects of any ultrastructural study and can be especially challenging in high-pressure frozen specimens. Historically, osmium tetroxide has been the preferred fixative and staining agent for lipid-containing structures in freeze-substitution solutions. However, osmium tetroxide is not only a rare and expensive material, but also volatile and toxic. Here, we introduce the use of a combination of potassium permanganate, uranyl acetate, and water in acetone as complementing reagents during the freeze-substitution process. This mix imparts an intense en bloc stain to cellular ultrastructure and membranes, which makes poststaining superfluous and is well suited for block-face imaging. Thus, potassium permanganate can effectively replace osmium tetroxide in the freeze-substitution solution without sacrificing the quality of ultrastructural preservation. [ABSTRACT FROM AUTHOR]