Anabaena variabilis
A Microbial Biorealm page on the genus Anabaena variabilis
Classification
Higher order taxa
Bacteria; Cyanobacteria; Nostocales; Nostocaceae; Anabaena
Genus and Species
Anabaena variabilis
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NCBI: Taxonomy |
Description and significance
Anabaena variabilis is a bacteria strain of blue-green algae that are known as cyanobacteria. Cyanobacteria are able to carry out photosynthesis, fix nitrogen from the environment, and also produce hydrogen. This feature of creating hydrogen with energy from the sun has made it popular in many laboratories in the world. The main role in its sequencing and research is because of the previous data collected regarding its physiology, biochemistry, and genetics can be better understood (4). This particular strain has also been described to have a “complex life cycle” that involved many types of cells that differentiate. The cells described were the “Heterocysts for nitrogen fixation, akinetes (spores) for survival, and hormogonia for motility and establishment of symbiotic associations with plants and fungi” (4).
The organism Anabaena variabilis was isolated at the U.S. Department of Energy Joint Genome Institute (DOE JGI). The DOE JGI listed that it sequenced the genomes of the organisms through the use of “whole-genome shotgun” (5). It described the technique as randomly “shearing” the genome DNA and then re-assembling it by comparing similar sequences and then inferring the original genome. The institute lists the three different size fragments that it can use and gives an example of how the procedure is done (5).
Genome structure
Anabaena variabilis has been sequenced and the data gathered showed that the circular DNA contains 6,365,727 base pairs (2). The information on the site shows that the GC-content of the organism is at 41.4% and that the genome as of now codes for 5043 proteins and 62 RNA strands (3). The cyanobacteria also have three plasmids which are named plasmid A, B, and C (3). The plasmids probably affect the organism’s ability to produce immunity to harmful substances and also provide the codes for certain proteins. Respectively, the plasmids each codes for 344, 31 and 243 proteins within the cyanobacteria (3).
Some interesting characteristics about this organism are some of its genes. It contains two gene clusters, nif1 and nif2, that code for Mo-nitrogenase (7). It also has another gene cluster, vnf, which codes for V-Fe cofactor nitrogenase. Each of the nitrogenase are activated under different conditions allowing the cyanobacteria to function. The Anabaena variabilis is also one of the few prokaryotic organisms that contains the enzyme Phenylalanine ammonia lyase (PAL), which helps deaminate phenylalanine to cinnamate (6).
Cell structure and metabolism
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Ecology
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Pathology
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Application to Biotechnology
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Current Research
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References
Edited by Phuoc Nam Nguyen, student of Rachel Larsen and Kit Pogliano
