A tiny ciliate with a indentation in the middle of its body is completely still. Its cilia are extended but unmoving, as if it were in a coma. For some reason, it suddenly jumps to another location. How is such a quick reaction possible from a state of immobility?
Commentary by Prof. Yuji Tsukii, Hosei University This organism belongs to genus Uronema.
Cyclidium is characterized by a fringe of long cilia called velum surrounding its mouth, which is located on the side of the cell. Cyclidium can also be identified by long cilia at the rear end. Unlike Cyclidium, the organism in this video does not have velum or long cilia at the rear end. The front of its body is flat lacks cilia. Therefore this organism is probably in the genus Uronema.
Also appearing in the video is a long filamentous alga which may be Tribonema.
A Strobilibidium with its strawberry-like shape creates a whirlpool through the motion of its mouth cilia. Surrounding organisms cannot resist the vortex and are pulled into the mouth of Strobilibidium and transferred inside. Even a large Euglena is drawn in by the whirlpool and has trouble escaping. It appears to dance in the turbulent water near Strobilibidium's mouth.
Commentary by Prof. Yuji Tsukii, Hosei University This organism is either Strombidium or Strobilidium, which are similar to each other.
In the case of Strobilidium the adoral zone has continuous membranelles, while Strombidium does not have continuous membranelles and both ends of its membranelles extend backward.
We must be able to clearly observe the adoral zone of membranelles in order to distinguish between the two organisms.
Behavior of Euplotes A large ciliate called Euplotes is gathering food with the dense cilia around its mouth. Small flagellates are sucked into the mouth one by one. They are transferred to the food vacuole which already contains plenty of food. One of the caudal cirri near the rear end shows characteristic movement. At first the body seems to be flat when viewed from above. When the organism moves over to a particle, we can see it from the side. It almost lookes like a turtle holding onto the particle with its "hairy legs" (cirri).
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to say whether this organism is Euplotes eurystomus
or E. woodruffi, because the exact shape of its nucleus cannot be identified.
In spite of having a long body, this ciliate is flat like a ribbon. The organism is thus able to move delicately through the narrow spaces between particles.
Commentary by Prof. Yuji Tsukii, Hosei University This ciliate may belong to either genus Loxodes or genus Remanella.
These groups look similar and are distinguished mainly by the following points: (i) the presence or absence of a fibrous structure in the cytoplasm, and (ii) the structure of the mouth area. Since these characteristics cannot be seen clearly in this video, it is difficult to determine to which genus this ciliate belongs.
