Fixed Versus Live Specimens
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Click on the image to view the movie
(live specimen enables time-lapse imaging, 2 MB, 12")
A confocal microscopy
image with fixed specimen. This is a C. elegans
with tubulin labeled in green
A MPFE microscopy
image with live specimen. This is a C. elegans
embryo with GFP fused with tubulin.
The specimen is no longer alive and the tissue/cell structure has been preserved (usually chemically with formaldehyde or alcohols).
- Advantages: the tissue can be stained to accentuate specific structures, the tissue is static. Specimens can be prepared in large numbers. The specimen can be re-analyzed at a later time.
- Disadvantages: fixations can alter the tissue. You cannot see dynamic changes within the specimen.
- Examples: 1) antibody-specific labeling, 2) ultra-structure analysis (e.g.: EM)
- Advantages: dynamic changes within the specimen can be seen. It is likely to provide a truer representation of the phenomenon of interest.
- Disadvantages: often can only visualize one specimen at a time (thus is more time consuming). The specimen can only be used once.
- Examples: 1) GFP, 2) time-lapse (e.g.: DIC)
Common Cell Biology Techniques
Common Microscopy Techniques
Electron Microscopy (EM)
(Flash movie, 460K, movie length: 27")
TEM specimen is a C. elegans embryo (cross-sectioned).
SEM specimen is a bunch of C. elegans (surface imaging).
This bioclip illustrates commonly used microscopy in C. elegans research. It does not focus on the technical aspects of microscopes but rather emphasizes how each type of microscopy helps researchers observe biology events. Microscopies addressed are DIC, confocal, multiphoton, TEM and SEM. Computational processing, such as color mapping, used in current microscopy is also illustrated.
(A Flash movie, 50 MB, movie length: 19' 44")