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Spider Beetle (Gibbium psylloides)
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Although this beetle is a rich brown color with golden legs and antennae, the colors in the image to the left are not the true colors, but only an approximation painted onto the image in Photoshop. Color, as we see it, is the detection of photons of different wave lengths, which can not be "seen" in the SEM.
Although electrons may have different "wavelengths" or energies, they do not have color as we see it. The images collected in the SEM are more or less intensity maps of electrons being deflected towards a detector. For typical SEM, the detector has a charge that attracts weak electrons. This is what gives SEM images their characteristic look of bright edges and few shadows. |
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C. elegans, the Nematode of choice
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To the left is an image of an adult hermaphrodite of C. elegans. This nematode's natural environment is the soil of temperate regions of the world. Here the worm can self-fertilize, or mate sexually with a male worm. The resulting single celled embryos develop into an organism containing over 900 individual cells comprising several organ systems. These include a digestive system, reproductive system, and a complex nervous system. The animal undergoes growth phases, and molts and along the way exhibits growth, behavior, aging and senescence.
All of these traits can be found in higher animals, but C.elegans has a few advantages over higher animals when it comes to basic research. The entire animal is transparent, and can be viewed, intact, under a microscope. The lifespand is only 2-3 weeks, and colonies of nematodes can be grown as easily as plates of bacteria. With all of these advantages, it is no wonder that so many people are turning to C. elegans as a model system. For more information please see http://www.wormatlas.org/ |
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| Cultured Lymphocytes infected with retrovirus | |||||||||||||||||||||||
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Lymphocytes, or white blood cells, grow suspended in fluid. In their natural environment, this would be blood. These particular cells, however, have been modified to grow in a laboratory environment. This cell line was originally derived from a patient with leukemia, and the cells were manipulated, or transformed, so that they could divide indefinitely, if give the proper conditions.
Along the way they were unintentionally infected with a murine type-C particle (a member of the retroviridae). Although the virus has co-existed with the cell line for quite some time, few if any published images at the EM level exist. To learn more about viruses, see All the virology on the WWW. Ramos cells provided by Dr. R. Leskov. |
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| Compare SEM and TEM images |
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