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Recent extensive surveys of archaea presence in the animal gut, based on 16S rRNA analysis, have provided a comprehensive view of archaea diversity and abundance. [27] [28] [29] These studies revealed that only a few archaeal lineages are present, with the majority being methanogens, while non-methanogenic archaea are rare and not abundant ...
In one study of the feces of nine adults, five of the samples contained archaea capable of producing methane. [13] Similar results are found in samples of gas obtained from within the rectum. Even among humans whose flatus does contain methane, the amount is in the range of 10% or less of the total amount of gas. [14]
Archaea exhibit a great variety of chemical reactions in their metabolism and use many sources of energy. These reactions are classified into nutritional groups, depending on energy and carbon sources. Some archaea obtain energy from inorganic compounds such as sulfur or ammonia (they are chemotrophs).
The exact mechanism is still a topic of debate but the most widely accepted theory is that the archaea use the reversed methanogenesis pathway to produce carbon dioxide and another, unknown intermediate, which is then used by the sulfate-reducing bacteria to gain energy from the reduction of sulfate to hydrogen sulfide and water.
Reduced sulfur compounds are oxidized by most organisms, including higher animals and higher plants. [2] Some organisms can conserve energy (i.e., produce ATP) from the oxidation of sulfur and it can serve as the sole energy source for some lithotrophic bacteria and archaea. [3]
It has been proposed that thermophilic archaea would be expected to have higher GC content within their DNA, because GC pairings have three hydrogen bonds, while AT pairings have only two. Increasing the number of hydrogen bonds would increase the stability of the DNA, thereby increasing the energy required to separate the two strands of DNA.
Chemoautotrophs can use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia or organic sources to produce energy. Most chemoautotrophs are prokaryotic extremophiles , bacteria , or archaea that live in otherwise hostile environments (such as deep sea vents ) and are the primary ...
Venenivibrio stagnispumantis gains energy by oxidizing hydrogen gas.. In biochemistry, chemosynthesis is the biological conversion of one or more carbon-containing molecules (usually carbon dioxide or methane) and nutrients into organic matter using the oxidation of inorganic compounds (e.g., hydrogen gas, hydrogen sulfide) or ferrous ions as a source of energy, rather than sunlight, as in ...