Details for Frank Abernathy entry for Bioscapes 2014
The common thread between all of these photomicrographs is to demonstrate that the
DNA structure within eukaryotic chromosomes is far more complex than depicted in
classical texts where chromosomes are illustrated as little more than super wound
single strands of chromatin. Instead, they seem to be comprised of a complex network
of circular structures which add another rich layer to the genetic complexity of the
nucleus. More information on this can be found at the following blog:
http://evolution4.wordpress.com.
All images are from mouse L-1210 cells in various degrees of degradation on
microscope slides. UV fluorescent and phase contrast photomicrographs were taken
with a Nikon microscope and captured with 35 mm film at 100-400x. Acridine orange
was used as the fluorescent stain.
Image 1
This is a composite image containing nine images of mouse L-1210 cells in various
states of breaking up. Living cells in cell medium were placed onto microscope slides,
stained with acridine orange, and allowed to die under coverslips while being
photographed using UV fluorescence. Early in the process, cells would begin to bleb
and long thread-like extensions attached to smaller blebs would begin to emerge from
them (A). In other cases, bizarre structures would develop that look very much like
colonies of yeast cells (B and C). When cell remnants were exposed to 0.1N HCl and
re-examined, complex structures were generated with multiple hierarchical levels of
repeating circular elements (E-I). Note that some of these circular structures contain
“hubs”.
Image 2
Fig.1: Scanning electron microscopy image (10KV at 500x magnification). Mouse cells
heat fixed to slides, rinsed with distilled water, and fixed with glutaraldehyde. Rinsed,
covered with saran wrap, inverted, and heated to allow material to migrate to the other
side of the slide.
Figs. 2 - 11: Phase contrast images at 400x magnification. Images are digitally
enlarged.
Fig. 12: UV fluorescent microscopy, (400x). Digitally enlarged.
Image 3
Figs. 13 -14, 16-17: UV fluorescent microscopy, treated with 0.1N HCl (400x). Digitally
enlarged.
Figs. 15: Phase contrast of image in Fig. 16.
Figs. 18: Scanning electron microscopy image (15KV at 400x magnification).
Processed as in Fig 1.
Figs. 19 - 20, 23, 25-28: Phase contrast images at 400x magnification. Images are
digitally enlarged.
Figs. 21-22: Phase contrast images at 400x magnification. Images are digitally
enlarged. Prepared using techniques similar to those used for scanning election
microscopy.
Fig. 24: Same as 23 but in UV fluorescent mode.
Image 4
All images but 52 are from mouse L-1210 cells in various degrees of degradation on
microscope slides.
Figs. 29 - 51: Phase contrast images at 400x magnification. Images are digitally
enlarged.
Fig. 51: Transmission electron microscopy was performed using a Hitachi HU-12
transmission electron microscope at 50 kilovolts. Purified mouse nuclear matrix DNA
was heated for 1 minute to 80 degrees in DNA spreading buffer containing 40%
formamide, chilled on ice, spread onto copper grids, dried, stained with 5% uranyl
acetate, and subjected to low angle shadowing with palladium-gold. 125,000x
magnification.