Desulforudis audaxviator
Taylor Robinson

 Man’s pursuit of gold has led him all around the world in search of adventure and wealth.  Little did he know that he would find one of nature’s treasures buried deep underneath Africa.  It was 2.8 kilometers down the Mponeng gold mine that a sample of ground water was found containing only one microbe, a gram-positive rod shaped bacteria.  In a microbe diversity test of the water sample, it was found that 99.9% of the DNA collected was from one microorganism, named Candidatus Desulforudis audaxviator.  This means that D. audaxviator is the first known organism to encompass its entire ecosystem.  Such seclusion has given D. audaxviator abilities that differ immensely from other bacteria.  It has traded DNA with archaea, adapted to high temperatures and no light, and it has learned to live off of almost nothing. 

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 The unique name, Candidatus Desulforudis audaxviator, was given to the microbe by two of its founders, Tullis Onstott and Dylan Chivian.  The name Candidatus means that the microbe is unculturable by known methods.  This is probably due to the extreme heat and lack of oxygen necessary for D. audaxviator’s survival.Tullis Onstott classified the microbe under the genus Desulforudis for its ability to get energy from sulfate and its rod shape.  Dylan Chivian coined the name audaxviator from a quote of the book “Journey to the Center of the Earth”, by Jules Vernes, that luckily was in Latin.  It says, “descend, bold traveler, and attain the center of the Earth”, where bold traveler in Latin is Audax viator (Chivian).  Such a unique name can only be given to a unique microbe.

 On its long journey towards the center of the earth, taking millions of years, D. audaxviator has acquired a unique set of genes incorporated from encounters with ancient archaea through horizontal gene transfer.  These genes allow it to fix nitrogen and carbon from inorganic sources, similar to the method archaea use.  Living deep underground for such a long time has also stripped D. audaxviator of the ability to use oxygen as an electron acceptor in its metabolic pathways, thus making it a strict anaerobe.  Instead of oxygen, sulfate is used as an electron acceptor. 

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 Not only is D. audaxviator capable of surviving without organic compounds, light, or oxygen, it is also able to survive at 60°C and in a ph of 9.3.  The ability to endure these severe conditions is given credit to D. audaxviator’s extensive genome, which contains 2157 genes instead of the 1500 that most bacteria possess in stable environments (Chivian).  These genes allow the microbe to live in almost all conditions except in the presence of oxygen.  If the ph or temperature changes to a more unfavorable condition, D. audaxviator is able to form a spore that protects its DNA from heat, extreme ph, and the lack of water.

 Astrobiologists have hypothesized that underneath the surface of many planets other microbes similar to that of D. audaxviator may exist.  This is because of D. audaxviator’s gift to gather all of the nutrients it needs from surrounding rocks and dissolved CO2, and its capability to make all of its amino acids from elemental nitrogen or ammonia.  It is also capable of living without the necessity of oxygen, which is fairly scarce on celestial bodies other than Earth.  D. audaxviator is a perfect candidate for evidence that it is possible for only one living organism to survive totally isolated in its environment. 

References

Chivian, Dr. Dylan. "Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth." Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth (2008): 1-168. ScienceMag. ScienceMag, 10 Feb. 2008. Web. 16 Oct. 2010. <http://www.sciencemag.org/cgi/data/322/5899/275/DC1/1>.

Chivian, Dr. Dylan. "Environmental genomics reveals a single-species ec... [Science. 2008] - PubMed result." National Center for Biotechnology Information. 10 Oct. 2008. Web. 16 Feb. 2010. <http://www.ncbi.nlm.nih.gov/pubmed/18845759?dopt=Abstract>.

Chivian, Dr. Dylan. "Environmental Genomics Reveals a Single-Species Ecosystem Deep Within Earth." ScienceMag. 10 Feb. 2008. Web. 16 Feb. 2019. <http://www.sciencemag.org/cgi/content/full/322/5899/275>.

Chivian, Dr. Dylan. "At 2.8 km down, a 1-of-a-kind microorganism lives all alone." PhysOrg.com - Science News, Technology, Physics, Nanotechnology, Space Science, Earth Science, Medicine. 9 Oct. 2008. Web. 16 Feb. 2010. <http://www.physorg.com/news142777731.html>.

Images

Suwansawad, Thanya. 2008. Photograph. PhysOrg.com - Science News, Technology, Physics, Nanotechnology, Space Science, Earth Science, Medicine. 9 Oct. 2008. Web. 16 Oct. 2010. <http://www.physorg.com/news142777731.html>.

Wanger, Greg, and Gordon Southam. Photograph. ABC News/Technology. 10 Oct. 2008. Web. 16 Feb. 2010. <http://abcnews.go.com/Technology/story?id=5998582&page=1>.

*Disclaimer - This report was written by a student participaring in a microbiology course at the Missouri University of Science and Technology. The accuracy of the contents of this report is not guaranteed and it is recommended that you seek additional sources of information to verify the contents.

 

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