''Methanogenium frigidum'' is a
psychrophilic, H2-using
methanogen
Methanogens are microorganisms that produce methane as a metabolic byproduct in hypoxic conditions. They are prokaryotic and belong to the domain Archaea. All known methanogens are members of the archaeal phylum Euryarchaeota. Methanogens are com ...
from
Ace Lake,
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
.
Description and metabolism
Cells are psychrophilic, irregular, slightly
halophilic
The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ...
and non-
motile coccoids (diameter 1.2 to 2.5
μm
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Unit ...
). They require salt to grow. They prefer
low temperatures: their optimal temperature is 15 °C, and they cannot grow at 18 °C–20 °C. They reduce
carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
with
hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...
to produce
methane
Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Eart ...
, but it may be possible that they use other substrates as well. One experiment showed that these cells grow best in the presence of
yeast extract
Yeast extracts consist of the cell contents of yeast without the cell walls; they are used as food additives or flavorings, or as nutrients for bacterial culture media. They are often used to create savory flavors and umami taste sensations, a ...
.
Genome
The genome of this species differs from those of archaea that prefer higher temperatures. It contains more polar amino acids, particularly Gln and Thr, and fewer non-polar ones, particularly Leu. Unlike
hyperthermophiles, in psychrophiles, the
GC content is the most important factor to the stability of the
tRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino ac ...
.
References
Further reading
*
*
*Garrett, Roger A., and Hans-Peter Klenk, eds. Archaea: evolution, physiology, and molecular biology. Wiley. com, 2008.
External links
*
LPSNType strain of ''Methanogenium frigidum'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
Archaea described in 1997
Euryarchaeota
{{Euryarchaeota-stub