Gracilicutes

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Gracilicutes
EscherichiaColi NIAID.jpg
Escherichia coli cells magnified 25,000 times
Scientific classification
Domain: Bacteria
(unranked): Gracilicutes
Kingdoms/Phyla

Proteobacteria
Planctobacteria
Sphingobacteria
Spirochaetae

Gracilicutes (Latin: gracilis, slender, and cutis, skin, referring to the cell wall) is a controversial taxon in bacterial taxonomy.

Traditionally gram staining results were most commonly used as a classification tool, consequently until the advent of molecular phylogeny, the Kingdom Prokaryotae (as the domain Bacteria was known then) was divided into four phyla,[1]

This classification system was abandoned in favour of the three-domain system based on molecular phylogeny started by C. Woese.[3][4]

This taxon was revived in 2006 by Cavalier-Smith as an infrakindgom containing the phyla Spirochaetae, Sphingobacteria, Planctobacteria, and Proteobacteria.[5] However, this taxon is not generally accepted and the three-domain system is followed.[6]

It is a gram-negative clade that branched off from other bacteria just before the evolutionary loss of the outer membrane or capsule, and just after the evolution of flagella.[5]

Relationships[edit]

The following graph shows Cavalier-Smith's version of the tree of life, indicating the status of Gracilicutes.[7]

References[edit]

  1. ^ GIBBONS (N.E.) and MURRAY (R.G.E.): Proposals concerning the higher taxa of bacteria. International Journal of Systematic Bacteriology, 1978, 28, 1-6.
  2. ^ MURRAY (R.G.E.): The higher taxa, or, a place for everything...? In: N.R. KRIEG and J.G. HOLT (ed.) Bergey's Manual of Systematic Bacteriology, vol. 1, The Williams & Wilkins Co., Baltimore, 1984, p. 31-34
  3. ^ Woese, C. R. (1987). "Bacterial evolution". Microbiological reviews 51 (2): 221–271. PMC 373105. PMID 2439888.  edit
  4. ^ Don J. Brenner, Noel R. Krieg, James T. Staley (July 26, 2005) [1984(Williams & Wilkins)]. George M. Garrity, ed. Introductory Essays. Bergey's Manual of Systematic Bacteriology 2A (2nd ed.). New York: Springer. p. 304. ISBN 978-0-387-24143-2. British Library no. GBA561951. 
  5. ^ a b Cavalier-Smith T (2006). "Rooting the tree of life by transition analyses". Biol. Direct 1: 19. doi:10.1186/1745-6150-1-19. PMC 1586193. PMID 16834776. 
  6. ^ Krieg, N.R.; Ludwig, W.; Whitman, W.B.; Hedlund, B.P.; Paster, B.J.; Staley, J.T.; Ward, N.; Brown, D.; Parte, A. (November 24, 2010) [1984(Williams & Wilkins)]. George M. Garrity, ed. The Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres, Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and Planctomycetes. Bergey's Manual of Systematic Bacteriology 4 (2nd ed.). New York: Springer. p. 908. ISBN 978-0-387-95042-6. British Library no. GBA561951. 
  7. ^ Cavalier-Smith T (2006). "Cell evolution and Earth history: stasis and revolution". Philos Trans R Soc Lond B Biol Sci 361 (1470): 969–1006. doi:10.1098/rstb.2006.1842. PMC 1578732. PMID 16754610.