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Updated: May 23, 2026
Preparation of embryos for Electron Microscopy of the Drosophila embryonic heart tube
Published on: December 21, 2009
Transmission electron microscopy of thin sections of Drosophila: conventional chemical fixation of embryos using
Abstract:
High-pressure freezing (HPF) followed by freeze-substitution is a valuable method for specimen preservation for transmission electron microscopy (TEM) in Drosophila. However, not all projects require this level of precision. In addition, some tissues are too large to fit into the HPF specimen carriers, and some fly tissues such as eyes and ovaries do not freeze well. This protocol describes a trialdehyde fixation procedure for embryos, to be used in situations where optimal preservation is not required or when HPF is not an option. Because the vitelline membrane is impermeable to aqueous solvents, it is necessary to either mechanically disrupt it or render it permeable by treatment with organic solvents. Good ultrastructural preservation has been achieved by puncturing embryos immersed in fixative with extremely sharp tungsten needles, as described here.
Related Concept Videos
01:20Preparation of Samples for Electron Microscopy
01:03Fixation and Sectioning
The simplest type of preparation is the wet mount, in which the specimen is placed in a drop of liquid on the slide. A liquid specimen can be directly deposited on the slide using a dropper. Solid specimens, such as skin scraping, can be placed on the slide before adding a drop of liquid to prepare the wet mount. Sometimes the liquid is simply water, but stains are often added...