The ''Coriobacteriia'' are a class of

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bact ...

bacteria within the

Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be terrestrial or aquatic. They are of great economic importance to humans because agriculture and forests depend on their contributions to s ...

phylum.Ludwig, W., Euzéby, J., Schumann, P., Busse, H. J., Trujillo, M. E.,Kämpfer, P. & Whitman, W. B. (2012). Road map of the phylum Actinobacteria. In: Bergey's Manual of Systematic Bacteriology, pp. 1–28. Eds. M. Goodfellow, P. Ka¨mpfer, H. J. Busse, M. E. Trujillo, K. Suzuki, W. Ludwig & W. B. Whitman. Springer-:New YorkClavel T, Lepage P & Charrier C. (2014). The family Coriobacteriaceae. In: The Prokaryotes, pp. 201-238. Springer-:Berlin Heidelberg Species within this group are non

sporulating In biology, a spore is a unit of sexual reproduction, sexual or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of ...

, strict or facultative anaerobes that are capable of thriving in a diverse set of ecological niches. '' Gordonibacter'' species are the only members capable of motility by means of flagella within the class. Several species within the ''Coriobacteriia'' class have been implicated with human diseases that range in severity. '' Atopobium'', '' Olsenella'', and ''

Cryptobacterium ''Cryptobacterium'' is a genus of Actinomycetota, in the family Coriobacteriaceae The Coriobacteriaceae a family of Actinomycetota The ''Actinomycetota'' (or ''Actinobacteria'') are a phylum of all gram-positive bacteria. They can be t ...

'' species have responsible for human oral infections including

periodontitis Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main cau ...

halitosis Bad breath, also known as halitosis, is a symptom in which a noticeably unpleasant breath odour is present. It can result in anxiety among those affected. It is also associated with depression and symptoms of obsessive compulsive disorder. ...

, and other endodontic infections. ''

Eggerthella ''Eggerthella'' is a bacterial genus of Actinomycetota, in the family Coriobacteriaceae. Members of this genus are anaerobic, non-sporulating, non-motile, Gram-positive bacilli that grow singly, as pairs, or in short chains. They are found in t ...

'' species have been associated with severe blood bacteraemia and

ulcerative colitis Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...

Molecular signatures and phylogenetic position

Historically, all ''Coriobacteriia'' species were placed within a single order (''Coriobacteriales'') and a single family (''Coriobacteriaceae''). This view, however, was not reflective of accurate evolutionary interrelationships within the class. The current taxonomic view is justified by the presence of several

conserved signature indels Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers ...

(CSIs) that have been found at the different taxonomic ranks. These CSIs are specific and represent synapomorphic characteristics that can be used to distinguish groups within the ''Coriobacteriia'', both at the family and order levels. The distinction of the orders within the ''Coriobacteriia'' is also supported phylogenetic tree branching and by consistent characteristics; members belonging to the ''Coriobacteriales'' are glucose-fermenting, saccharolytic species while the ''Eggerthellales'' order has species that are consistently unable to ferment glucose and are asaccharolytic. CSIs have also been used to resolve the phylogenetic position of the ''Coriobacteriia'' among all bacteria where they have been found exclusively for all species within the class, delineating them from other

. The ''Coriobacteriia'' are an early branching lineage within the Actinomycetota phylum The deep branching of the class has led to dispute over its membership within the phylum and whether or not it is a true Actinomycetota group. A CSI in the form of a single amino acid insert in the enzyme deoxyuridine 59-triphosphate (dUTP) nucleotidohydrolase has been found that is shared by all ''Coriobacteriia'' members, as well as several Actinomycetota species, and absent from all other bacteria. This CSI provides unambiguous support for ''Coriobacteriias membership within the Actinomycetota.

Phylogeny

References

{{Taxonbar, from=Q26211126 Gram-positive bacteria

Molecular signatures and phylogenetic position

Phylogeny

See also

References