Biology Reference
In-Depth Information
FIGURE 8.3
(A) Left heart ventricle from an overnight fasted mice was excised and fixed with Trump's
fixative, post-fixed in 1% osmium tetroxide, and investigated with transmission electron
microscopy. (B) Thin sections were processed as (A) and stained with lead citrate and uranyl
acetate and then investigated with transmission electron microscopy. (B
0
) Sample is
processed as (B) but visualized with high magnification. (C) Sample is processed as (A) and
further stained with OTO. Black arrows indicate mitochondria (M) and lipid droplets (LDs).
Respective magnification is reported on the micrograph in white.
uranyl acetate and lead stain (
Fig. 8.3
B and B
0
), LDs are not uniformly stained
and few LDs appear to be without any lipid content (
Fig. 8.3
B). Often, the extent
of lipid extraction varies from one specimen to another but is always proportional
to the staining time and number of heavy metal staining. Effort to enhance the
staining of the LDs in TEM sample preparation may backfire too. The heart muscle
TEM specimen stained by the OTO method exhibits greatly enhanced membrane
of the LDs (
Fig. 8.3
C). However, the edges of the LD membrane show irregularities
and pitting, an appearance not observed in the control specimen when LDs were
stained with only osmium and uranyl acetate during the embedding process
(
Fig. 8.3
B
0
).
In order to maximize the ultrastructural preservation of not only the LDs but also
of the aqueous cytoplasmic content as well as organelles such as mitochondria and
