After being collected from a paddy field, the sample was put on DNB agar plate (diluted nutrient broth with agar) with a drop of distilled water for 4 days, and then observed.
A ciliate is busily swimming in various directions, making sharp turns and suddenly reversing course.
Commentary by Prof. Yuji Tsukii, Hosei University This ciliate belongs to order Stichotrichida.
A variety of ciliates are included in this group. To identify them to the species level, it is necessary to stain the cirri by a special technique and to observe the number and arrangement of the cirri. Since we cannot see any cirri on the ciliate in this video, we cannot determine even which genus it is.
However, when the organism changes direction, it also changes the body shape itself. Therefore this organism is certainly not a member of genus Stylonychia in Sporadotrichina, Oxytrichidae group.
Organisms belonging to genus Oxytricha or genus Urostyla change directions in a similar manner to the organism in this video.
After being collected from a paddy field, the sample was put on DNB agar plate (diluted nutrient broth with agar) with a drop of distilled water for 4 days, and then observed.
This large ciliate is moving around within a small area. As the center of the body is slightly narrow, this organism might be preparing to divide.
A variety of ciliates are included in this group. To identify them to the species level, it is necessary to stain the cirri by a special technique and to observe the number and arrangement of the cirri.
The cell in this video may be in the process of division, because it appears there are two sets of a peristome connected to a cytostome (mouth): one is located at the front of the cell, and the other is in the middle, just behind where the cell is slightly narrow. This narrow middle part will gradually pinch together and finally divide into two daughter cells.
After being collected from a paddy field, the sample was put on DNB agar plate (diluted nutrient broth with agar) with a drop of distilled water for 4 days, and then observed.
One of the ciliates in this video is nearly ready to divide into two daughter cells. While other ciliates swim around rapidly, this one has slowed nearly to a standstill.
This cell is obviously about to divide. The surrounding ciliates may be the same species.
When these swimming ciliates change direction, the tops of their cells also bend toward the new direction. Therefore these ciliates probably belong to genus Oxytricha.
However, according to the Monograph of the Oxytrichidae (Ciliophora, Hupotrichia) by Helmut Berger : Kluwer Academic Publishers, 1999, 113 species with similar shapes are included in genus Oxytricha. Therefore identification of this ciliate to the species level is almost impossible.
After being collected from a paddy field, the sample was put on DNB agar plate (diluted nutrient broth with agar) with a drop of distilled water, and kept for 4 days before observation.
Because of the quick movements of these ciliates, it was hard to observe their cell structure at high magnification.
Commentary by Prof. Yuji Tsukii, Hosei University This ciliate belongs to genus Urostyla in order Stichotrichida.
