Candidatus (biology)

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Culture of a bacterium from a marine sponge in a Petri dish with a culture medium made of agar-agar

Candidatus is a term that is placed infront ofthe name of a bacterial species in scientific nomenclature if this species has not yet been cultivated . The spelling is then for example " Candidatus Desulforudis audaxviator " for a bacterium whose genetic material ( DNA ) was isolated from the water at a depth of more than 1500 m in South African mines or for " Candidatus Thiobios zoothamnicoli" for abacteriumlivingon the colonies of an eyelash animal , sulfide-reducing bacterium, which previously could only be cultivated together with the colonies.

use

For a valid description and publication of a bacterial species it is necessary to isolate and cultivate this species from others. Such a bacterial strain is then kept in a collection of bacterial cultures such as the German Collection of Microorganisms . The physiology and way of life of the bacteria can thereby be studied. For many species this cultivation is not possible under laboratory conditions because they live as parasites or endosymbionts in the cells or in the organs of other organisms or occur in the deep sea under extreme ecological conditions.

The status Candidatus is used when a microbe species is well characterized, primarily through molecular genetic analysis of the genetic material, but could not be isolated and kept permanently in a bacterial culture under laboratory conditions without the presence of other cells .

history

In 1994, Murray and Schleifer proposed that such inadequately described bacterial taxa should be designated as Candidatus without taxonomic rank instead of a species or genus . Candidatus is therefore the preliminary stage to a possible taxon. It was recommended that a list of these candidates for a taxon be published in a list in the International Journal of Systematic Bacteriology (now the International Journal of Systematic and Evolutionary Microbiology ). In 1995, Murray and Stackebrandt recommended the implementation of the Status Candidatus for incompletely described bacterial taxa and became increasingly important. According to this proposal, the Candidatus category is to be used to describe prokaryotic organisms of which more than one DNA sequence is known if the conditions for a complete description according to the International Code of Nomenclature of Bacteria are not met. In addition to the genetic information, such a description should also contain all available information about morphological characteristics and ultrastructure, metabolism and reproduction .

Individual evidence

  1. ↑ BJ Tindall, P. K Merger, JP Euzéby, A. Oren: Valid publication of names of prokaryotes according to the rules of nomenclature: past history and current practice. Int. J. Syst. Evol. Microbiol. 56 (11), pp. 2715-20, November 2006, PMID 17082418 . doi : 10.1099 / ijs.0.64780-0 .

Web links

literature

  • RGE Murray and Karl-Heinz Schleifer: Taxonomic notes: a proposal for recording the properties of putative taxa of procaryotes . In: Int. J. Syst. Bacteriol. 44, pp. 174-176, 1994
  • Judical Commission of the International Committee on Systematic Bacteriology: Minutes of the meetings. July 2nd and 6th 1994 , Prague, Czech Republic. In: Int. J. Syst. Bacteriol. 1995, 45, 195-196.
  • RGE Murray and E. Stackebrandt: Taxonomic Note: implementation of the provisional status Candidatus for incompletely described procaryotes. In: Int. J. Syst. Bacteriol. 45, pp. 186-187, 1995
  • E. Stackebrandt, W. Frederiksen, GM Garrity, PAD Grimont, P. KAMPER, MCJ Maiden, X. Nemse, R. Rossello-Mora, J. Swings, HG Trüper, L. Vauterin, AC Ward and WB Whitman: Report of the ad hoc committee for the re-evaluation of the species definition in bacteriology. In: Int. J. Syst. Evol. Microbiol. 52, pp. 1043-1047, 2002