Candidatus

Candidatus is a term that is prepended to the name of a bacterial species in the scientific nomenclature when this type could not be cultivated. The notation is then for example " Candidatus Desulforudis audaxviator " for a bacterium whose genetic material (DNA) from the water at a depth of more than 1500 m was isolated in South African mines or for " Candidatus Thiobios zoothamnicoli " living for the colonies of a batting animalcule, sulfidreduzierendes bacterium that could previously be cultivated only with the colonies.

Use

For the valid description and publication of a bacterial species, it is necessary to isolate this species from other and cultivate. Such a bacterial strain is then held in a collection of bacteria cultures, such as the German collection of microorganisms. The physiology and behavior of bacteria can be studied. In many species, this cultivation is not possible under laboratory conditions because they live as parasites or endosymbionts in the cells or in the bodies of other organisms, or occur in the deep sea under extreme environmental conditions.

Status Candidatus is therefore used when a microbe is indeed well characterized, mainly by molecular genetic analysis of the genetic material, but could not be isolated under laboratory conditions without the presence of other cells and permanently maintained in a bacterial culture.

History

1994 beat Murray and Schleifer ago to designate such Bakterientaxa insufficiently described instead as a species or genus as Candidatus without taxonomic rank. Candidatus then, is the precursor to a possible taxon. It was recommended to publish a list of these candidates for a taxon in a list in the International Journal of Systematic Bacteriology (now International Journal of Systematic and Evolutionary Microbiology ). In 1995, Murray and Stackebrandt the implementation of the status Candidatus for incompletely described recommended Bakterientaxa and became increasingly important. The category Candidatus to be used for the description of prokaryotic animal according to this proposal, 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 is Such a description also contain all available information on morphological features and ultrastructure, metabolism, and reproduction.