Thesis-PDF - IAP/TU Wien

Figure 6.10: The middle part of an E. gracilis cell, the apical part would
be found toward the top. Some crystalline storage grains, paramylums, show
as cameo shapes (arrowheads) in the pellicle. They press against the pellicle
after the drying process. Intermittent contact mode AFM image, Amplitude
trace.
tuned to the alga’s need of lubrication, could prove to be an excellent target for
viscoelastic studies using AFM force curves.
As of our knowledge this is the first time that pellicular strips and mucilage
of an E. gracilis cell were imaged at this resolution. The available data in the
literature, mostly SEM and TEM data does not include reliable information about
distribution and properties of Euglena’s mucilage.
A feature that has not yet been observed by either SEM or TEM is presented
in Fig. 6.13. The figure shows indentations as imaged by AFM that occur in the
in the middle of pellicular strips. Such features are not to be seen in SEM and
TEM images. Pellicle pores known from the literature differ in size and position
from the features found. They are located to the side of a pellicular strip whereas
the new indentations are found at the center of a strip. The fact that the new
indentations can be imaged with the AFM might be due to our gentle preparation
methods that differ from preparation methods for SEM/TEM.
For comparison, a SEM image is given in Fig. 6.14 that does not show any
features in the middle of pellicular strips. The features seen are well known pellicle
pores and they are not located centered on the strips as opposed to the indentations
measured by AFM.
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