A ciliate-like organism is sticking its head into aggregate. Various types of diatoms come in and out of the aggregate, pushing against this unknown organism.
Commentary by Prof. Yuji Tsukii, Hosei University The shape of this organism does not change at all, and even the cytoplasm inside
does not move.
This unidentified organism surrounded by a shell has possibly died,
and it is difficult to say what it is because the front of the cell is behind a particle.
If its shell has an opening at the front, it could be in the genus Euglypa.
Among particles at the bottom of Hirose River, a small ciliate is foraging. This tiny organism is so absorbed in its search for food that it doesnt seem concerned by the giant ciliates swirling around it.
Commentary by Prof. Yuji Tsukii, Hosei University Unfortunately this organism is too small and lacking in remarkable features to determine what it is.
An organism is twitching in a narrow space between particles. After a while it begins to contract and expand its body, hides itself behind the particles, then suddenly jumps out and shoots out of our view. The organism is gone in an instant so it is difficult to determine if it is a ciliate.
Commentary by Prof. Yuji Tsukii, Hosei University As described in the video commentary, this is may be a ciliate, but it is difficult to know for sure.
Particles in the river are composed of organic debris, aggregated soil particles, sand grains and minerals. Their surface is covered with nutrients and numerous bacteria, so various kinds of small protozoa take turns feeding. They appear to be enjoying the feast.
Commentary by Prof. Yuji Tsukii, Hosei University I have no special comments in this video.
A round brown organism with a yellow tint is standing still beside a particle, but we cannot tell what it is.
Commentary by Prof. Yuji Tsukii, Hosei University This organism may be a type of golden-brown algae, Crysophyceae,
based on three main visible features:
1) The shape is round,
2) Thick yellowish-brown structure like a protoplast is noticed in the gap
between the outer shell and inner cell,
3) There is a contractive vacuole in both sides of the shell.
The organism's round shape suggests that it is in a cycstic (dormant) form.
From this shape, it is difficult to decide to what genus this organism belongs.
Feeble organisms Two small organisms are attached to the surface of a swollen-looking, round organism, which is probably a weakened ciliate. The attached flagellate and diatom are also weak, as none of the three is moving at all.
Commentary by Prof. Yuji Tsukii, Hosei University We can see a small attached diatom cell on the right side of the picture.
The abnormal shape of this ciliate seems to have been caused by a large bite, leaving the organisms weakened and able to move only feebly.
Commentary by Prof. Yuji Tsukii, Hosei University As the title suggests, this ciliate exhibits a very abnormal shape. It is possible that when the sample was collected, the body might have be injured by sand particles. Therefore it is difficult to say to what genus this ciliate belongs.
This ciliate has a strange projection at the rear end. There may be a missing piece from an attack by another organism, because this type of projection is rarely seen. The ciliate with its slightly bent mouth is actively swimming around particles and algal cells.
Commentary by Prof. Yuji Tsukii, Hosei University The projection at the rear end of this organism might be damage caused by sand particles when it was collected from the river. As the front of the body has retained a normal shape, it can be identified to the genus level. It probably belongs to either genus Loxodes or genus Remanella, both of which have a beak-like shape at the front.
The whole body might have been longer and narrower before being injured suggesting that this organism is Remanella, but it is difficult to say which species it is.
This colorless ciliate seems to have a hard, partially concave surface. It is standing still, slowly moving the long cilia near its mouth. There is no evidence that it is catching any food with this lazy movement.
Commentary by Prof. Yuji Tsukii, Hosei University This organism cannot be identified even to the genus level because the body was injured and fragmented by sand particles when it was collected. Only the front part remains intact.
The rear end of this small oval ciliate is slightly narrow and bent. The organism rotates in a stationary position. No one can guess why it continues this rotary motion.
Commentary by Prof. Yuji Tsukii, Hosei University This organism looks like it might be a fragmented ciliate, but it is also possible that this is its normal shape. Even so, it is difficult to say what genus it is. The fact that it is swimming backward is unusual, and suggests that the cell shape has been greatly transformed.
Commentary by Prof. Yuji Tsukii, Hosei University I don’t know what this is. It is probably not a living organism.
In nature, there are crystals called plant opals which originate from plant cells.
Plant opals exhibit various shapes depending on the plant species.
However, the image in this video does not exhibit a normal shape, so it may not be a plant opal.
A small ciliate in the center of this view is still except for the movement of its cilia.
Just as we begin to wonder if it will ever move, it turns and quickly darts away.
Commentary by Prof. Yuji Tsukii, Hosei University This organism is certainly a kind of ciliate with a contractile vacuole, but it is difficult to identify. The location of the cytostome (mouth) at the top suggests that it belongs to the class Prostematea. The Prostematea class includes Coleps and Prorodon. However this ciliate is not covered with a hard armor-like plate, which Coleps has, and it is much smaller than Prorodon. The cylindrical structure of the cytostome is not clear in this video, so we cannot say what kind of ciliate it is.
A small slender ciliate proceeds slowly while also turning along its axis. The body narrows in the middle, which usually indicates the process of division. Soon it stops moving forward and twists repeatedly in the same position, in an effort to divide into two separate bodies. Unfortunately this dividing process is interrupted after 30 minutes by the approaching water boundary.
Commentary by Prof. Yuji Tsukii, Hosei University It is doubtful that this video shows the dividing process, because the cell shape and location of the cilia are not the same in the two cells. It is most likely that the middle of the cell has become narrow because it was pinched or squeezed when it was collected.
This ciliate is about 100 microns long and is shaped like a leaf. The body and surrounding cilia are not moving at all except for a vacuole in the cytoplasm that is expanding and shrinking. Perhaps this ciliate is exhausted from hunting or fleeing from a predator.
Commentary by Prof. Yuji Tsukii, Hosei University This organism must be a living ciliate because its whole body is covered by cilia, and a contractile vacuole is moving in the cytoplasm near the top. However, we cannot determine the location of the cytostome (mouth) in this video, which is an important criterion for identification of ciliates. Therefore we cannot be more specific about which type of ciliate this is.
The surface to which this organism is attached may be a kind of organic material rather than a biological organism.
This diatom appears to be dead. There are brown particles inside, and small organisms go in and out through various openings in its silicate cell wall.
Commentary by Prof. Yuji Tsukii, Hosei University The shell is all that remains of a diatom that has died. Because of the large number of species of diatoms, we cannot say to which one this shell belongs. If we could observe the shell from the top, side and other angles, it might be easier to figure out, but it is impossible when viewed from only one direction.
This organism covered with a reddish-brown shell may be a flagellate called Trachelomonas. It is swimming around too rapidly for us to clearly see its flagellum.
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to say if this organism is Trachelomonas. The organism in this video is different from a typical Trachelomonas, which has a spherical, eliptical or spindle-shaped shell all wuthout a dent. This organism has a dent near the center and may have one or two flagella. If this organism were trachelomonas, it would have only one flagellum extending forward.
Algae are often covered with a shell. In particular, green algae have shells of various shapes. The organism appearing in this video, however, is too small for us to recognize the characteristic shape of its shell.
(Green algae with shell:Please refer to the following additional examples)
This small amoeba is deeply dented on one side of the body, and there are pseudopodia-like structures all over the surface. The first part of the video was taken in real time, so the amoeba appears nearly motionless. However, in the time-lapse segment, we can see the amoeba moving slowly, with the particles in its cytoplasm moving as well.
Commentary by Prof. Yuji Tsukii, Hosei University It is difficult to say what type of amoeba this is. It might belong to Heliozoa as the cell shape does not change. However, some smaller Heliozoa with very thin pseudopodia have recently been reclassified from the Heliozoa group to the Filosea group, including Rabdiophrys and Pompholyxophrys. As the organism in this video appears to have very thin pseudopodia, it might be Rabdiophrys belonging to Filosea.
Small Heliozoa(and other small amoebae) are often found in the field, but to what group these organisms should be classified can be perplexing.
After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for a few days.
At first glance this object appeared to be a round aggregate rather than a living creature, but more careful observation revealed numerous small organisms moving inside. By fast-forwarding the video to ten times the normal speed, we still cannot identify the organisms but we can certainly confirm that they are alive.
Commentary by Prof. Yuji Tsukii, Hosei University We cannot identify the organisms in this video; we can only say that numerous small organisms are moving together using either flagella or amoeboid movement. But as the individual organisms are small and packed together too closely, it is difficult to determine how they move. We might be able to understand more by taking the body apart to observe each individual cell, or by comparing it to similar living bodies nearby. Mysterious organisms like these are sometimes found in natural, uncultivated fields.
After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for a few days.
The body of this organism is transparent like a plastic bag. Small particles of various sizes are moving inside.
Commentary by Prof. Yuji Tsukii, Hosei University This unknown organism of about 20-30μm long is covered by a transparent gel. Four seconds after the start of the video, its body suddenly contracts. If this organism were Vorticella, the contracting left half would be the oral part (peristome) and the right half would connect to the stalk (which we cannot see). Vorticella sometimes secretes a gel-like substance to protect itself against a hostile or unfavorable environment, but we cannot identify this organism as Vorticella with the information available.
Euglena cells are usually cylindrical or long and tapered like a spindle, but in the field I frequently find Euglena exhibiting such a ball-like shape. When the environment becomes hostile, the cell becomes round and stands still, and may secrete a gel around itself. This form of Euglena is often found in autumn.
The sample was observed immediately after being collected.
While clinging to soil aggregates, this round greenish organism is continually moving. Such
a strange organism is often observed in the microbial world.
Commentary by Prof. Yuji Tsukii, Hosei University This organism cannot be identified at all. The green color suggests that it contains chlorophyll. It moves despite sticking to aggregates but we cannot determine how it moves.
After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for four days.
This tiny organism is continually flutters as it moves around. It is too small for us to see whether it has a flagellum or not.
Commentary by Prof. Yuji Tsukii, Hosei University This organism is smaller than 20μm long and we cannot determine whether it is a flagellate or a ciliate. The resolution of the video is too low for us to confirm its exact shape, though its manner of swimming suggests that it uses a flagellum for locomotion.
Soils from the L, H, and A layers were sampled from the Tohoku University Botanical Garden in Sendai. This is a video of an organism taken from the H layer, which is below the L layer. There are fairly decomposed organic debris and humic substances in this layer. At first organisms could not be found in the newly collected soil, so the samples (including water) were left for one month and then observed.
Commentary by Prof. Yuji Tsukii, Hosei University This organism belongs to Helizoa, but the image is too small to determine the genus.
We cannot see the exact shape of the spines or other protrusions that are useful to distinguish the genera of Helizoa.
We also cannot tell whether the cell surface is double-layered or covered with a gel-like substance, which is another characteristic that would help to determine the genus.
Sampling Date : 06 December 2006
Sampling Site : Tohoku University Botanical Garden in Aobayama Google Map
2006Botanical Garden in AobayamaVII
Soils from the L, H, and A layers were sampled from the Tohoku University Botanical Garden in Sendai. This is a video of an organism taken from the A layer, the first layer below the soil surface (which is composed of L, F, and H layers). The A layer is mainly composed of mineral particles and humus. At first organisms could not be found in the newly collected soil, so the samples (including water) were left for one month and then observed.
Commentary by Prof. Yuji Tsukii, Hosei University The cell of this cylindrical organism is slightly tapered at the front end and rounder at the rear end.
The mouth is on the side near the front, which might indicate that it is a thin Tetrahymena cell.
This organism has lines running lengthwise along the whole cell, a characteristic of Sathrophilus.
However, the mouth of Sathrophilus is set back a little from the front end, whereas the mouth of the organism in this video is located closer to the front. This suggests that the organism may not be Sathrophilus.
Sampling Date : 06 December 2006
Sampling Site : Tohoku University Botanical Garden in Aobayama Google Map
