Archaea


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Archaea

Evolutionary biology
One of the three domains of living organisms: Archaea, Bacteria and Eukaryota. While Archaea are single-celled, they are unlike bacteria given their independent evolutionary history. Archaea differ from Eukaryota in their ribosomal structure and the presence—in some—of introns in the genome, as well as other features (e.g., different membrane composition).
 
Molecular biology
Archaea are of interest in biotechnology as they have unique biochemical features (e.g., enzymes of theromophiles, such as Taq polymerase, the “workhorse” enzyme of PCR) and are extremely stable at high temperatures. Archaea include metabolic oddities (e.g., extreme halophiles, which live in extremely salty environments), methanogens (which produce methane) and sulphur-dependant extreme thermophiles (which can live in extremely hot environments).

Archaea phyla
• Crenarchaeota
• Euryarchaeota
• Korarchaeota
• Nanoarchaeota
• Thaumarchaeota (recently proposed)

Archaea

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References in periodicals archive ?
Erguder TH, Boon N, Wittebolle L, Marzorati M, Verstraete W (2009) Environmental factors shaping the ecological niches of ammonia-oxidizing archaea.
Because ammonia is a major component of sweat, Archaea might play a role in nitrogen turnover and skin health.
CRISPR interference RNA-directed adaptive immunity in bacteria and archaea.
A novel finding of our study is to quantitatively show a reduction of the total methanogenic archaea population in the yeast-supplemented groups (Figure 2).
The results showed that there is biological transmutation of magnesium to calcium in human systems mediated by actinidic archaea dependent on cerium for its growth.
La version detallada del sistema de Cavalier-Smith, publicada en 2004, conservaba los imperios Prokaryota y Eukaryota, pero Archaea quedaba como un subreino del reino Bacteria, se reintroducia el reino Protozoa y hacia su aparicion el reino Chromista--propuesto por Cavalier-Smith en 1981--que, a pesar de su nombre--del griego [TEXTO IRREPRODUCIBLE EN ASCII], chroma, 'color'--, incluye organismos sin color, si bien todos tienen clorofila c y otros pigmentos que no se hallan en las plantas.
And, it appears that the number of methane-producing archaea in the Tammar wallaby is less than what we typically see in sheep and cattle.
Currently there is little information on the relationship between Archaea and chronic periodontitis.
Later, however, comprehensive sequence comparisons of the nucleic acids and proteins of these microorganisms showed fundamental differences to bacteria, so that evolutionary biologists reclassified the five kingdoms of life to three domains: archaea, single-celled organisms lacking nuclei; bacteria, which also lack nuclei; and eukarya, organisms with nuclei (single-celled protists, single- and multi-celled algae, single- and multi-celled fungi, plants, animals, and humans).
A partir de los anos 60, cuando se descifro el codigo genetico y se comprobo su universalidad, la investigacion de esta cuestion perdio gran parte de su carga especulativa y en la actualidad esta generalmente aceptado que toda la diversidad biologica del planeta se agrupa en tres grandes dominios, Archaea, Bacteria y Eucarya, que a su vez proceden de una misma celula primigenia: LUCA (Last Universal Common Ancestor).
These include unicellular green algae of the genus Dunaliella, which is the sole primary producers in the lake, and a variety of heterotrophic prokaryotes, aerobes, anaerobes as well as Archaea [4, 5].