Nodularia

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Nodularia
Nodularia spumigena

Nodularia spumigena

Systematics
Domain : Bacteria (bacteria)
Department : Cyanobacteria ("Cyanobacteria")
Class : Cyanobacteria (Cyanobacteria)
Order : Nostocales
Family : Nostocaceae
Genre : Nodularia
Scientific name
Nodularia
( Mertens in Jürgens ) ex Bornet & Flahault 1888

Nodularia is a genus of filamentous cyanobacteria . In summer,surface blooms of the toxic species Nodularia spumigena , which is also the type species,regularlyoccur in the Baltic Sea .

features

The filamentous, long, unbranched cell chains ( coenobia ) consist of over a hundred individual cells, which can also form in groups or clusters, and are more or less straight, curved, culled or irregularly spiral with a sleeve open at both ends. At regular intervals they carry heterocysts , specialized cells that are responsible for binding atmospheric nitrogen. The trichomes are uniserial, cylindrical and rarely shortened at the ends. The planktonic species have gas vesicles, while the benthic species do not. The cell contents are yellowish, pale olive-green or blue-green, the thylakoids are irregularly culled and scattered over the cell volume. The heterocysts have the same shape, but sometimes also smaller or larger than the vegetative cells. Akinetes (immobile cells) are barrel-shaped or spherical.

Occurrence

Nodularia occurs primarily in brackish water and salt water up to 30 PSU and is distributed worldwide. Surface blooms occur in the Baltic Sea in summer. The stable stratification of the surface water of the Baltic Sea leads to a depletion of nitrogen compounds. Due to the ability of diazotrophic cyanobacteria to reduce molecular atmospheric nitrogen to ammonium, they can use the remaining amount of phosphate compounds in the water column for growth. Due to gas vesicles in the cells, the coenobia float to the surface and are driven to the coast by the wind.

toxicity

Some Nodularia strains produce the hepatoxin nodularin . This liver poison is an oligopeptide and related to the microcystins which are produced by the cyanobacterium Microcystis . Several incidents are known of fatal poisoning of ducks, dogs, sheep, pigs, horses and cattle after ingestion of Nodularia . The LD50 value of nodularin in the mouse model organism is between 30 and 250 µg / kg body weight, depending on the structural variant of the toxin.

Genome

Currently (2009) the genome of the strain Nodularia spumigena CCY9414 is being annotated . The genome is approximately 5.3 megabase pairs in size .

Systematics

Nodularia belongs to the Nostocaceae family :

Unexplained species:

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