NC_007412:147757 Anabaena variabilis ATCC 29413 plasmid C, complete sequence
Host Lineage: Anabaena variabilis; Anabaena; Nostocaceae; Nostocales; Cyanobacteria; Bacteria
General Information: These cyanobacteria are bluegreen algae that are capable of fixing carbon and nitrogen. They form long filaments and can be found worldwide in various aquatic environments as well as some terrestrial ones. These bacteria can form a variety of differentiated cell types, including spore-like cells (akinetes), small motile filaments (hormongia) and most importantly, heterocysts that are nitrogen-producing cells. The heterocyst produces multiple layers outside of its cell wall, shuts down photosystem II in order to inhibit oxygenic photosynthesis and ramps up metabolism in order to use up the oxygen present. Heterocysts donate fixed nitrogen compounds as amino acids to neighboring cells and in return receive a photosynthetically produced carbon source such as sucrose. These organisms produce toxic blooms in aquatic environments that are harmful or fatal to animals and humans due to the various cyanotoxins they produce. Anabaena variabilis is a filamentous heterocyst-forming cyanobacterium that fixes nitrogen and CO2 using the energy of sunlight via oxygen-evolving plant-type photosynthesis. In addition, this organism has been studied extensively for the production of hydrogen using solar energy.