Thesis-PDF - IAP/TU Wien

cavity and is used for regulatory functions concerning the cell fluid (cytosol 9 ). The
vacuole surrounds the bases of the flagella. It is limited by a unit membrane and
discharges rhythmically every 20 − 30 seconds.
The boundaries of the elongated Euglena body are formed by the outer tripartite
(three-layered) plasmalemma membrane surrounding the pellicle composed
of interlocking and articulating flexible strips. These ribbon-like strips are spirally
arranged and underlain by microtubuli.
Inside the cell fluid, near the center of the cell the nucleus containing all the
cell DNA can be found. The chloroplasts of Euglena account for a great percentage
of cell organelles - its main energy providing facility. The cornered shape of these
is characteristic for Euglena gracilis. A lot of other entities such as paramylum
granules, lipid bodies, crystalloid bodies and phospholipid vesicles can be found
spread throughout the cell.
4.3.2 Motory System and Phototaxis
The elongated cell swims edgewise while it rotates around its long axis. It pulls
itself through the water by means of the flagellum - thus moving in the direction
of the apical part, where the locomotory (emergent) flagellum protrudes.
Figure 4.4: Apical part of Euglena viridis. Image adapted from [94].
The apical part of the cell bears the reservoir, an inversion of the pellicle,
with two thin rods emerging out of its base part, the two flagella. One of these
9 The cytoplasm in comparison is defined as the sum of the cytosol and the embedded organelles
and inclusions.
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