A Euglena changing its shape

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. At a first glance this looks like a round green organism with a red part in the center.

But after a while, the organism elongates and swims around, revealing itself as a Euglena. Later it gradually returns to the former shape and stops moving entirely.

Commentary by Prof. Yuji Tsukii, Hosei University
This video records a Euglena in the process of changing shape. Many species are included in Euglena and recently the standards for classification have changed a lot. Therefore identification of Euglena has become more difficult.

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

It is necessary to know the shape of the chloroplast, surface appearance, changeability of its body shape, and the shape and number of its paramylon particles.

The round cell in this video is nearly 200μm in diameter. Ribbon-like protoplasts inside seem to spread radially from the center. These features suggest that the organism is Euglena schmitzii, but if you refer to my photograph of E. schmitzii, you will not see a red part and the shape is different. Therefore the organism cannot be determined to the species level.

Sampling Date : 17 November 2006

Sampling Site : KASHIMADAI paddy field  Google Map