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An amoeba hunting for food I

Here a large amoeba is actively hunting and catching food in various ways. When a food particle becomes caught on the tip of the pseudopodium, the pseudopodium carries the food to the center of its body, by becoming shorter and broader until the food is engulfed.


Commentary by Prof. Yuji Tsukii, Hosei University
This organism is possibly a floating Vannella.

http://protist.i.hosei.ac.jp/PDB/Im.....

It usually attaches onto solid surfaces and appears like a flat fan, but when it is torn off from the surface by water movement, it transforms into a radial shape.

Floating in water, Vanella expands its narrow pseudopodia to find a new surface to which it can attach.

Vanella looks for food - bacteria and small protozoa - as it moves along solid surfaces.

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map

An amoeba hunting for food II

When a ciliate or flagellate accidently runs into the amoebas body, two pseudopodia tightly grasp the unlucky prey and transfer it to the central part. At first the prey struggles to get free, but soon stops moving. Finally the prey loses its shape and becomes unrecognizable.


Commentary by Prof. Yuji Tsukii, Hosei University
This organism resembles Vanella in its radial shape, but unlike Vanella, it catches food while floating freely. The organism may be Vexillifera or it may belong to a related family.

http://protist.i.hosei.ac.jp/PDB/Im.....

It sometimes moves on a solid surface, while at other times it proceeds while swaying its long pseudopodium in front.

An important criterion for classifying amoeba is their method of locomotion. Since amoeba appear similar when they are floating, it is difficult to determine what species this organism is.

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map

An amoeba hunting for food III

When the amoeba concentrates on catching food using one or two pseudopodia, the remaining pseudopodia become very short. When many food particles approach all at once, the amoeba becomes confused and cannot decide which pseudopodium to extend. When this happens, the hunt is a complete failure.


Commentary by Prof. Yuji Tsukii, Hosei University
The organism is Vexillifera.

http://protist.i.hosei.ac.jp/PDB/Im.....

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map