Candidatus

Candidatus Prometheoarchaeum syntrophicum cells dividing under SEM (c). Cryo-electron tomography image of a single cell (d). White arrows indicate large membrane vesicles. Scale bar = 1 μm (c) and 500 μm (d)

In prokaryote nomenclature, Candidatus (abbreviated Ca.; Latin for "candidate of Roman office") is used to name prokaryotic taxa that are well characterized but yet-uncultured.[1] Contemporary sequencing approaches, such as 16S ribosomal RNA sequencing or metagenomics, provide much information about the analyzed organisms and thus allow identification and characterization of individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in in vitro study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity.

  1. ^ Stackebrandt, E. (1 May 2002). "Report of the ad hoc committee for the re-evaluation of the species definition in bacteriology". International Journal of Systematic and Evolutionary Microbiology. 52 (3): 1043–1047. doi:10.1099/ijs.0.02360-0. PMID 12054223.[permanent dead link]