Simkaniaceae is a family of bacteria in the order Chlamydiales, class Chlamydiia, phylum

Chlamydiota The Chlamydiota (synonym Chlamydiae) are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of ...

, domain

Bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

. Species in this family have a chlamydia-like cycle of replication and their

ribosomal RNA Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal ...

genes are 80–90% identical to ribosomal genes in the

Chlamydiaceae The Chlamydiaceae are a family of gram-negative bacteria that belongs to the phylum Chlamydiota, order Chlamydiales. Chlamydiaceae species express the family-specific lipopolysaccharide epitope αKdo-(2→8)-αKdo-(2→4)-αKdo (previously ca ...

. The Simkaniaceae are not recognized by

monoclonal antibodies A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a Lineage (evolution), cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Mon ...

that are specific for Chlamydiaceae

lipopolysaccharide Lipopolysaccharide (LPS), now more commonly known as endotoxin, is a collective term for components of the outermost membrane of the cell envelope of gram-negative bacteria, such as '' E. coli'' and ''Salmonella'' with a common structural archit ...

. The family Simkaniaceae currently includes two

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

: '' Simkania'' and '' Fritschea''. The type species is ''Simkania negevensis'', and its natural host is not known. It is readily grown in monolayers of eukaryotic

Vero cell Vero cells are a lineage of cells used in cell cultures. The 'Vero' lineage was isolated from kidney epithelial cells extracted from an African green monkey ('' Chlorocebus'' sp.; formerly called ''Cercopithecus aethiops'', this group of monk ...

s. Serological evidence and PCR indicate that ''S. negevensis'' is widespread among humans. Two ''Fritschea'' species have been identified in

insects Insects (from Latin ') are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed ...

. These are

candidatus 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. Contemporary sequencing approaches, such as 16S ribosomal R ...

species because they only grow in insect bacteriocytes and have not been cultured

in vitro ''In vitro'' (meaning ''in glass'', or ''in the glass'') Research, studies are performed with Cell (biology), cells or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in ...

. Whiteflies are the host of Candidatus ''Fritschea bemisiae'' (strain Falk). Scale insects are the host of Candidatus ''Fritschea eriococci'' (strain Elm). ''Simkania negevensis'' and ''Fritschea bemisiae'' have a group I intron in the 23S rRNA, unlike other characterized chlamydial rRNA genes. The introns are closely related to group I introns in the 23S rRNA of chloroplasts and mitochondria in algae and amoebae.

Taxonomy

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...

(NCBI) * "''Ca.'' Amphritriteisimkania" Davison & Hurst 2023 ''Ca.'' Amphrikana" (sic)** "''Ca.'' A. amoebophyrae" Davison & Hurst 2023 * "''Ca.'' Fritschea" Everett et al. 2005 ** "''Ca.'' F. bemisiae" Everett et al. 2005 ** "''Ca.'' F. eriococci" Everett et al. 2005 * "''Ca.'' Neptunichlamydia" corrig. Pizzetti et al. 2016 ** "''Ca.'' N. vexilliferae" corrig. Pizzetti et al. 2016 * '' Simkania'' Everett, Bush & Andersen 1999 ** ''S. negevensis'' Everett, Bush & Andersen 1999 * "''Ca.'' Syngnamydia" Fehr et al. 2013 ** "''Ca.'' S. medusae" Viver et al. 2017 ** "''Ca.'' S. salmonis" Nylund et al. 2015 ** "''Ca.'' S. veneta" corrig. Fehr et al. 2013

References

{{Taxonbar, from=Q7517905 Chlamydiota

Taxonomy

See also

References