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Synula grows into a large colony and divides into smaller ones

Several Synula (colonies of brown flagellates) take turns feeding on a large particle. Successful feeding causes the Synula to grow larger, which makes it difficult to move quickly. One large Synula disappears briefly behind the particle and reappears as two smaller colonies, apparently having divided just out of view.

Commentary by Prof. Yuji Tsukii, Hosei University
(a) This video shows how a colony of Synula divides from one large colony to a smaller one, rather than each flagellate member dividing individually.

Synula is a colony of flagellate cells that, in the course of its symbiotic development, has included algal chloroplasts inside its flagellate members. Therefore Synula can get nutrients from the photosynthetic activity of those chloroplasts. But it is also possible that each flagellate in a Synula colony has the ability to take in food from outside.

(b) There are non-colonized flagellates that can take in food from outside.

(c) Ochromonas is a single-celled, motile, golden- brown alga, with the ability to perform photosynthesis, phagocytosis and osmotrophy. Therefore Ochromonas is easily cultured without bacterial food.

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map

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