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Methanoccoides is also a unique archeon in the sense that it is one of the few known psychrophilic archeons that have been discovered and thus have research.

History
m. burtonii was first discovered and isolated from a lake in Antarctica. Discovered by an Austrian scientist named harry burton, m. burtonii was quickly determined to be a pyschrophile. The environment m. burtonii was discovered had temperatures as low as 1 to 2 degrees Celsius, and it was later determined that the optimal temperature of growth was 23 degrees Celsius.

Psychrotolerance
A large amount of earth’s atmosphere is at or below 5 degrees Celsius. Methanococcoides burtonii are one of the first methanogenic archeaon extremophiles to have been discovered and extensively researched. Prior to their discovery there was little knowledge on the mechanism of adaptation to cold environments of methanogenic extremophiles. The discovery of M. burtonii will has enabled scientists to delve further into the advantageos traits and proteins that allow these organisms to sustain.

Cold Adaptation
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC532414/ Adaptation of microbes to cold environments has been studied, thanks to M. burtonii, to a reasonable extent. The majority of this research has been conducted using bacterial organsims such as Bacillus subtilis, although the majority of psychrophilic extremophiles in cold environments are in the archean domain. Since the discovery of m. burtonii, the investigation of archaean cold adaptation has taken a new turn. Two methods of adaptation have been extensively studied in M. burtonii, those being membrane lipid structure adaptation and protein usage.

Membrane Structure Adaptation
It is known that archaea represent a large proportion of the microbial biomass in “cold” environments, ie, ace lake where M. burtonii was discovered. The investigation of membrane lipid composition is a novel idea that has come forth following the discovery of m. burtonii. As environmentl temperature decreases, the lipid bilayer becomes rigid in a majority of wild type organisms. However, it has been discovered that increasing the proportion of unsaturated fatty acids in the membrane can sustain a liquid crystalline state. To accomplish this a denaturase enzyme is utilized. De novo synthesis allows for a permanent adaptation to cold environments, as is observed in m. burtonii. It was determined that the presence of unsaturated diether lipids (UDLs) provides a mechanism of cold adaptation in archaea. Certain UDLs have been discovered in M. burtonii. These UDLs are temperature sensitive, and growing them at different temperature affects the rate of unsaturation in the membrane. Thus, this provides evidence that M. Burtonii has the ability to control its membrane fluidity (with resepct to temperature). This ability therefore provides a plausible pathway to cold adaptation by archaea. Another molecule potentially responsible for membrane unsaturation, and thus cold adaptation, are isoprenoid side chains. Two specific enzymes, acetoacetyl-CoA thiolase and HMG-CoA synthase were discovered to participate in the mevalonate pathway in m. burtonii. Isoprenoid chains produced in this manner are fully unsaturated. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC532414/