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Domain : Bacteria (bacteria)
Trunk : Cyanobacteria (Cyanobacteria)
Class : Cyanobacteria (Cyanobacteria)
Order : Nostocales
Family : Microchaetaceae
Genre : Tolypothrix
Scientific name
Kützing ex Bornet & Flahault

Tolypothrix is a genus from the tribe of cyanobacteria (blue-green algae).


Tolypothrix forms falsely branched, blue-green to brown, single-row threads with a diameter of 6 to 20 µm. Like all bacterial cells , their cylindrical cells contain neither nuclei nor plastids . Each thread sits in its own gelatinous sheath. A fake side branch is created by fragmenting a thread at a pre-formed point where a single cell dies. This creates two separate threads that remain connected by the gelatinous sheath. One of the threads breaks out of the gelatinous sheath, the other thread differentiates one or more colorless, thick-walled cells, the so-called heterocysts, at the branching point . They are used for biological nitrogen fixation . The growth occurs through cell division within the thread.


The asexual reproduction is done by hormogonia , ie by capable of creeping thread fragments. Likewise Fadenfragmentation possible.

Sexual reproduction is absent in all cyanobacteria.


Tolypothrix lives on aquatic plants and on stones at the bottom of standing and flowing water. Some species survive the occasional dry run of their waters.

Types (selection)


  • Karl-Heinz Linne von Berg, Michael Melkonian u. a .: The Kosmos algae guide. The most important freshwater algae under the microscope. Kosmos, Stuttgart 2004, ISBN 3-440-09719-6 .

Web links

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