The ''Eggerthellaceae'' are a family 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 bacte ...

, rod- or coccus-shaped

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 soi ...

. It is the sole family within the order ''Eggerthellales.'' The name ''Eggerthellaceae'' is derived from the Latin term ''

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 ...

,'' referring to the type genus of the family and the suffix "-ceae," an ending used to denote a family. Together, ''Eggerthellaceae'' refers to a family whose nomenclatural type is the genus ''

''.

Biochemical characteristics and molecular signatures

Members of this family are mostly anaerobic, non-motile (with the exception of some ''Gordonibacter'' and ''Senegalimassilia'' species that exhibit motility), asaccharolytic and do not form spores. ''Eggerthellaceae'' species are commonly isolated from human and animal faeces and other human sources such as the colon, vagina, oral cavity and blood. Some species have also been isolated from human samples of periodontal or endodontic infections, Crohn's disease and severe blood bacteremia. The G+C content for ''Eggerthellaceae'' species is between 43.4 and 66.3 mol%. Analysis of genome sequences identified 13

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) in diverse proteins that are exclusively present in different ''Eggerthellaceae'' species. The proteins containing these CSIs are: contaexcinuclease ABC subunit UvrC,

DNA polymerase III DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of ...

subunit alpha,

ribonuclease III Ribonuclease III (RNase III or RNase C)(BREND3.1.26.3 is a type of ribonuclease that recognizes RNA, dsRNA and cleaves it at specific targeted locations to transform them into mature RNAs. These enzymes are a group of endoribonucleases that are c ...

, tRNA (N6-isopentenyl adenosine(37)-C2)-methylthiotransferase (MiaB), peptide chain release factor 2, 16S rRNA (cytosine(1402)-N(4))-methyltransferase,

elongation factor Tu EF-Tu (elongation factor thermo unstable) is a prokaryotic elongation factor responsible for catalyzing the binding of an aminoacyl-tRNA (aa-tRNA) to the ribosome. It is a G-protein, and facilitates the selection and binding of an aa-tRNA to t ...

, UDP-N-acetylglucosamine 1-carboxyvinyltransferase

subunit epsilon,

UDP-glucose 4-epimerase The enzyme UDP-glucose 4-epimerase (), also known as UDP-galactose 4-epimerase or GALE, is a homodimeric epimerase found in bacterial, fungal, plant, and mammalian cells. This enzyme performs the final step in the Leloir pathway of galactose ...

and

DNA-directed RNA polymerase A polymerase is an enzyme ( EC 2.7.7.6/7/19/48/49) that synthesizes long chains of polymers or nucleic acids. DNA polymerase and RNA polymerase are used to assemble DNA and RNA molecules, respectively, by copying a DNA template strand using base- ...

subunit alpha. The identified CSIs provide reliable and important means to distinguish members of ''Eggerthellaceae'' from all other Coriobacteriia as well as other bacteria.

Phylogeny

Eggerthellaceae phylogenetic relationships

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 Nomenclature ...

(LPSN). The phylogeny is based on whole-genome analysis. See figure for a detailed phylogenetic tree.

Notes

References

Actinomycetota {{actinobacteria-stub