Bacteria Genomes - ANABAENA VARIABILIS

Anabaena is a genus of filamentous N2-fixing cyanobacteria (blue-green algae) that are known for producing a suite of cyanotoxins (a toxin secreted by certain cyanobacteria) which range from the neurotoxic anatoxins and saxitoxins to the hepatotoxic microcystins.

Anabaena variabilis is a Gram Negative aeorobic motile filamentous heterocyst-forming cyanobacterium that fixes nitrogen and CO2 using the energy of sunlight via oxygen-evolving plant-type photosynthesis. In addition, strain ATCC 29413 has been studied extensively for the production of hydrogen using solar energy Anabaena variabilis has a complex life cycle that includes multiple types of differentiated cells: heterocysts for nitrogen fixation, akinetes (spores) for survival, and hormogonia for motility and for the establishment of symbiotic associations with plants and fungi. It has been studied extensively for over 40 years and is the strain of choice for many laboratories throughout the world.

A. variabilis, is important in global carbon sequestration via photosynthetic CO2 fixation. Because it can grow heterotrophically, it has been possible to create photosystem-I mutants that grow in the dark. It is unique in having three different sets of nitrogenase genes that function under different environmental conditions. The production of H2 by microorganisms has long been pursued actively. A practical process for biological H2 production using sunlight as the source of energy would create a major new source of sustainable and renewable energy, without greenhouse gas emissions or environmental pollution.

A third major area of interest in A. variabilis is comparative developmental analyses. Most cyanobacteria that form heterocysts also form spores, called akinetes, that protect against desiccation, cold, and phosphate-deprivation. Essentially every vegetative cell of A. variabilis can differentiate into an akinete. Despite the structural and physiological differences of akinetes from heterocysts, their development sufficiently resembles the development of heterocysts that it has been proposed that heterocysts are evolutionary derivatives of akinetes. It is an ideal organism in which to pursue analysis of akinete formation, akinete-pattern formation, and the comparative differentiation processes of heterocysts and akinetes.

References:

http://genome.jgi-psf.org/finished_microbes/anava/anava.home.html">http://genome.jgi-psf.org/finished_microbes/anava/anava.home.html
http://www.thelabrat.com/protocols/RestrictionEnzymes.shtml
http://www-cyanosite.bio.purdue.edu/cyanotox/toxiccyanos/anabaena.html