Hunting technique The shape of this ciliate called Strobilidium reminds us of a bell or strawberry. Although the body shape is similar to Vorticella, it does not have a stalk, yet like Vorticella, it rotates in a continuous arc. The whirlpool created by the rapid waving of the cilia surrounding its mouth pulls food into the organism.
Commentary by Prof. Yuji Tsukii, Hosei University This organism is Strobilidium.
The Protozoological Monograph, vol.3, 134, 2006 (Kreutz & Foissner), depicts the figure of Strobilidium with a narrow string at its rear end, and describes the organism as exhibiting rotatory movement while attaching itself to a surface by its string.
This is the top view of Strobilidium . We can see the strong whirlpool it creates from the way that surrounding organisms are sucked toward, and sometimes bounce off Strobilidium .
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to determine whether the organism in this video is Strobilidium or Strombidium.
A ciliate called Pleuronema is hiding between particles waiting for food. It is driven away by a Strobilidium which repeatedly jumps into Pleuronema's hiding place.
Commentary by Prof. Yuji Tsukii, Hosei University The organism hiding between particles is Pleuronema marinum.
Two Strobilidium are facing each other. The whirlpool between them is so strong that small flagellates around these bodies cannot swim freely. The movement of diatoms is not so strongly affected, but a large colony of flagellates, Synula, is forced to stop for an instant.
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to determine whether this organism is Strobilidium or Strombidium.
Two Strobilidium are connected to each other. Are they in the process of conjugation? In the top view, we cannot see a wall separating the organisms. From the side view, there is a transparent membrane structure that seems to connect the top of the two bodies. However, this conjugation fails because after 4 minutes, the cell walls of both organisms suddenly begin to collapse, and the cell contents spill out and scatter.
Commentary by Prof. Yuji Tsukii, Hosei University These 2 Strobilidium-like cells began their conjugation smoothly enough,
but unfortunately the rapid movement and collision caused tear in the cell membrane.
Various organisms such as Coleps, Strobilidium , Euglena, Diatom, and some small flagellates can be seen. This is the world of active microorganisms, which cannot be recognized with naked eye.
Commentary by Prof. Yuji Tsukii, Hosei University (a) It is difficult to determine whether this organism is Strobilidium or Strombidium.
Strobilidium
The cilia surrounding the mouth of Strobilidium are always moving. This organism has collected and stored numerous food particles in its body, but seems to want more.
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to determine whether this organism is Strobilidium or Strombidium.
We can’t be sure, but it might be a sign it has started to devide.
Stick-like structures are often identified at the rear end of Strobilidium, although whether these structures take part in cell division is not yet known.
A Strobilidium and a Stylonychia are feeding close to each other. Both ciliates are trying to attract food particles by moving the cilia around their mouths. However, the strong whirlpools that they both create interfere with each other's efforts. After a while, they change their strategy and move to separate places to feed.
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to determine whether this organism is
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.
Strobilibidium is basically a stationary feeder. It lacks a stalk but keeps a fixed position by attaching itself to other particles. When necessary, such as being disturbed by other organisms, it moves to another location to resume feeding. We can see its transparent vacuole contracting periodicalloy.
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 observe the adoral zone of membranelles in order to distinguish between the two organisms.
A transparent vacuole inside this organism, as described in the comment of this video, is formally called a contractile vacuole.
The whirlpool created by this Strombidium's cilia motion is so strong that small organisms are pulled toward the Strombidium, only to be repelled by the water current. Occasionally the Strombidium manages to capture food using the whirlpool hunting strategy.
Commentary by Prof. Yuji Tsukii, Hosei University This organism may be either Strombidium or Strombilidium.
Both organisms are distinguished by the pattern of cirri at the front end of the cell,
that is whether line of cirri is closed or whether line of cirri is not closed but
extends to backward.
But it is difficult to decide without checking the side view of a motionless cell.
The first part of this recording shows a Strobilidium ciliate at a higher magnification, the second part at a lower magnification, and the last part is in slow motion at a higher magnification. There is a strange protuberance on the side of its body, but we do not know the cause of this abnormality, or if it has a particular function.
Commentary by Prof. Yuji Tsukii, Hosei University Strobilidium can be difficult to distinguish from Strombidium due to their similar shapes and features.
The organism in this video is in fact Strombidium, not Strobilidium.
There are three species of ciliates with a similar shape:
i) Strobilidium: cirri surrounding the mouth extend downwards.
In this video, the cirri surrounding the mouth cannot be clearly identified.
However, the cell tapers at the rear, and with careful observation,
we can see numerous stick-like structures arranged like a ring
in the rear part of the cell.
These features are characteristic to Strombidium.
In Kahl’s Wimertiere oder Ciliata (Infusoria), two conjugating
Strombidium sulcatum cells both have pointed ends.
