Planctobacteria

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PVC group
ChlamydiaTrachomatisEinschlusskörperchen.jpg
Chlamydia trachomatis
Scientific classification (temporary)
Domain: Bacteria
Superphylum: PVC group
Phyla

Chlamydiae
Lentisphaerae
Planctomycetes
Verrucomicrobia

Synonyms

Planctobacteria Cavalier-Smith, 1987[1]

Planctobacteria is a taxon created by Cavalier-Smith, specifically a division (phylum).[note 1] However, it is not followed by the larger scientific community.[2] Cavalier-Smith postulated that the Planctobacteria probably lost or reduced their peptidoglycan cell wall twice.[3]

In the Cavalier-Smith bacterial megaclassification, it is within the bacterial Gracilicutes infrakingdom and comprises three classes Chlamydiae, Lentisphaerae, Planctomycetes, Verrucomicrobia.[3][4] These three groups in the traditional molecular phylogeny view are considered as phyla and also cluster together in what is referred to as the PVC superphylum, along with the candidate phyla OP3 and the Poribacteria.[5] It has been hypothesised that a member of the PVC clade might have been the host cell in the endosymbiotic event that gave rise to the first proto-eukaryotic cell.[6][7]

PVC superphylum[8][9][10]

Poribacteria





Planctomycetes



OP3





Chlamydiae




Lentisphaerae



Verrucomicrobia





Molecular evidence

Support for this superphylum has been found by examining the RNA polymerase protein RpoB.[11] This protein has a unique 3 amino acid insert in all sequenced Chlamydiae, Lentisphaerae and Verrucomicrobia species. A conserved protein of unknown function is present in all sequenced species from the phyla Chlamydiae, Lentisphaerae, Planctomycetes and Verrucomicrobia. This protein is absent in the Poribacteria.

Additional lines of evidence for the existence of this clade have been found.[12][13] These include the presence of membrane coat like proteins, tubulin, sterol synthesis and the presence of condensed DNA.

Study of additional proteins from this proposed syperphylum suggests that the Poribacteria may be separate from this clade.[11] The Planctomycetes may be basal to the Chlamydiae-Verrucomicrobia-Lentisphaerae clade.

Notes

  1. Historically bacteria were considered plants consequently the usage of "division" over "phylum" was brought over when the kingdom Monera was established. The bacteriological code has since imposed that the rank should be phylum and not division. Nevertheless, Cavalier-Smith adopts the term division.

References

  1. Cavalier-Smith, T. (1987). The origin of eukaryote and archaebacterial cells. Annals of the New York Academy of Sciences 503, 17–54.
  2. 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. <templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
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