Is this green protrusion alive?

After being collected from a paddy field, the sample was put on 1% agar plate with a drop of distilled water and kept for two days. An unknown green object protrudes from the surface of an aggregate. It is motionless, but could it be a living organism?

Commentary by Prof. Yuji Tsukii, Hosei University
It is difficult to identify this organism with certainty. It may be Oedogonium (filamentous green algae), which is typically cylindrical and slightly swollen on one side.

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

However, the body surface--which is assumed to be the cell wall--is partly discolored and has lost its shape, which means a long time must have been passed since the organism died.

Many green particles are crammed inside of the dead cell, and they are certainly alive.

These green particles are probably different from Oedogonium zoospores, because its zoospores are typically larger and number from one to only a few. Furthermore the zoospores cannot survive very long after the cell dies.

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

Therefore these numerous green particles are most likely tiny cyanobacterial cells such as Microcystis, which entered the dead cell of Oedogonium and proliferated there.

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

Sampling Date : 17 November 2006

Sampling Site : KASHIMADAI paddy field  Google Map