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6.2 AFM data and cell features
Below some images in AFM xy-mode are presented. They clearly demonstrate the
convenience of Atomic Force Microscopy as a tool for high resolution imaging of
E. gracilis cells. AFM data could be acquired of various features of the Euglena
gracilis cell, including cell walls, mucus excretion pellicle pores, crystalline cell
parts and new surface features not previously reported or visible on SEM/TEM
images available in the literature.
Fusing pellicle strips
In the left part of Fig. 6.6, the basal part of an E. gracilis cell shows the distinct
fusing of its pellicle strips. To our knowledge this is the first time that the strip
reduction patterns of E. gracilis have been imaged by AFM. Also in Fig. 6.6, to
the right, a schematic drawing of a pellicular strip reduction pattern is given. Such
patterns can provide information on algal evolutionary pathways and may also be
derived from mathematical expressions ([118]). AFM easily resolves pellicular strip
endings and can be used to compare how these differ from other strip parts.
Figure 6.6: Left: Detail of the basal part of an E. gracilis cell. Arrowheads
indicate end points of pellicular strips and broken lines hint at strip reduction
patterns. Intermittent contact mode AFM image, Amplitude trace. Right:
Diagram illustrating linear patterns of strip reduction at the posterior end
of Euglena mutabilis. Three consecutive strips pass whorl I, two pass whorl
I’ and only one passes whorl II. Image adapted from [118].
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