Wednesday, May 16, 2012

A term in microbiology: archaea, shortened from archaeabacteria to denote the third domain

In 1977, when Carl Woese and George Fox reformulated the prokaryote-eukaryote grouping as a result of their phylogenetic analysis based upon ribosomal RNA sequencing, they proposed three main branches for the tree of life: eubacteria (typical bacteria), archaebacteria (then only methanogenic bacteria) and urkaryotes that evolved into components of eukaryotic cells [1].  Now these three domains are named bacteria, archaea and eukarya, respectively. Animals, plants and fungi, for example, branch of as subdomains from the latter.

The name archaea was introduced in 1990 by Woese as a short form of the term archaeabacteria [2]. The intention further was to eliminate the bacteria connotation, since archaea significantly differ from “typical” bacteria.

Although the three-domain system finds wide acceptance today, this bacteriocentric scheme has also been critized since it fails to recognize cell symbiogenesis—a five-kingdom scheme has been suggested instead [3].

Archaea are now known to fill many places of our world (at least on Earth). They are thriving in harsh environments, but also in soils, swamps and animal colons. A peer-reviewed, open-access journal with the title Archaea exists in which research and review articles are published that cover topics in archaea biology, ecology and bioinformatics  [4].

Keywords: microbiology, three-kingdom system, phyla of life, taxonomy, nomenclature.

References and more to explore
[1] Carl Wose and George Fox: Phylogenetic structure of the prokarotic domain: The primary kingdoms. Proc. Natl. Acad. Sci. USA November 1977, 74 (11), pp. 5088-5090 [].
[2] Tim Friend: The Third Domain. The Untold Story of Archaea and the Future of Biotechnology. Joseph Henry Press, Washington, D.C., 2007; pp. 60-61 and 86.
[3] Lynn Margulis and Karlene V. Schwartz: Five Kingdoms. Henry Holt and Company, New York, Third Edition 1998.
[4] Hindawi Publishing Corporation: Archaea [].

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