''Cytobacillus'' is a genus of rod-shaped bacteria that stain either

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 ...

or Gram-variable in the family ''

Bacillaceae The Bacillaceae are a family of gram-positive, heterotrophic, rod-shaped bacteria that may produce endospores. Motile members of this family are characterized by peritrichous flagella. Some Bacillaceae are aerobic, while others are facultative ...

'' within the order ''

Bacillales The Bacillales are an order of Gram-positive bacteria, placed within the Bacillota. Representative genera include ''Bacillus'', ''Listeria'' and ''Staphylococcus''. See also * List of bacteria genera * List of bacterial orders This article li ...

.'' The type species for this genus is '' Cytobacillus firmus.'' Members of this genus was transferred from the ''

Bacillus ''Bacillus'' (Latin "stick") is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum ''Bacillota'', with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacilli ...

'' genus after

comparative genomics Comparative genomics is a field of biological research in which the genomic features of different organisms are compared. The genomic features may include the DNA sequence, genes, gene order, regulatory sequences, and other genomic structural lan ...

studies have determined they were sufficiently different by phylogenetic measures than ''

Bacillus subtilis ''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus ''Bacillu ...

'', the type species of the genus ''Bacillus''. The genus ''Bacillus'' has long been under close scrutiny by the scientific community due to its polyphyletic nature, displaying many distinct monophyletic groupings in various phylogenetic trees within the genus. In addition, while ''Bacillus'' species have a diverse range of biochemical characteristics, there is no unique characteristic that can be used to reliably distinguish all ''Bacillus'' species from other bacteria. Many studies have used phylogenetic and comparative genomic analyses as a means towards clarifying the complicated taxonomic relationships within ''Bacillus'', resulting in the transfer of many species into novel genera such as ''

Alkalihalobacillus ''Alkalihalobacillus'' is a genus of gram-positive or gram-variable rod-shaped bacteria in the family ''Bacillaceae'' from the order ''Bacillales''. The type species of this genus is '' Alkalihalobacillus alcalophilus.'' This genus comprises s ...

,'' '' Virigibacillus,'' ''

Brevibacillus ''Brevibacillus'' is a genus of Gram-positive bacteria in the family Paenibacillaceae The Paenibacillaceae are a family of Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain tes ...

,'' ''

Solibacillus ''Solibacillus'' is a genus of Gram positive, rod shaped, spore-forming bacteria. The first member of ''Solibacillus'' was first isolated in 1999, and was originally called ''Bacillus silvestris''. However, further studies on ''B. silvestris'' ...

'' and ''

Evansella ''Evansella'' is a genus of Gram-positive rod-shaped bacteria in the family ''Bacillaceae'' within the order ''Bacillales''. The type species for this genus is ''Evansella cellulosilytica.'' Members of ''Evansella'' was transferred from the genu ...

''. In addition, the genus ''Bacillus'' has been restricted to include only species closely related to ''

'' and ''

Bacillus cereus ''Bacillus cereus'' is a Gram-positive rod-shaped bacterium commonly found in soil, food, and marine sponges. The specific name, ''cereus'', meaning "waxy" in Latin, refers to the appearance of colonies grown on blood agar. Some strains are ha ...

''. The name ''Cytobacillus'' can be broken down into the prefix "cyto-" (from the Greek noun ''kytos'', referring to hollow, vessel, jar or a cell in biology) and the suffix "-bacillus" (from the Latin noun ''bacillus'', referring to a small staff or rod and Bacillus, the bacterial genus). Together, ''Cytobacillus'' refers to a rod-shaped cell.

Biochemical characteristics and molecular signatures

Members of ''Cytobacillus'' can be either

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cellu ...

facultatively anaerobic A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent. Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...

. All studied species of this genus has been observed to produce endospores under adverse environmental or nutritional conditions. ''Cytobacillus'' can be isolated and found a diverse range of locations, ranging from natural locations (soil, marine sediments), living organisms (human gut, earthworm) to pharmaceutical production sites. Most species are motile, and some are able to tolerate moderate saline conditions and high alkalinity environments. While ''Cytobacillus'' species can grow in temperatures ranging from 10–45°C, optimum growth occurs in the range 25–37°C. Three

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) have been identified as exclusively shared by most/all members of ''Cytobacillus'' in the following proteins: PDZ domain-containing protein,

histidinol dehydrogenase In enzymology, histidinol dehydrogenase (HIS4) (HDH) () is an enzyme that catalyzes the chemical reaction :L-histidinol + 2 NAD+ \rightleftharpoons L-histidine + 2 NADH + 2 H+ Thus, the two substrates of this enzyme are L-histidinol and NAD ...

and transcription-repair coupling factor. These CSIs were identified through the analysis of genome sequences from ''Cytobacillus'' species and provide novel molecular means to differentiate this genus from other ''Bacillaceae'' genera.

Taxonomy

As of May 2021, there are a total of 13 species with validly published names in the genus ''Cytobacillus''. Members of ''Cytobacillus'' are observed to group together in a monophyletic clade in phylogenetic trees created based on different datasets of conserved proteins as well as 16S rRNA genome sequences. This branching pattern is also observed in the

Genome Taxonomy Database The Genome Taxonomy Database (GTDB) is an online database that maintains information on a proposed nomenclature of prokaryotes, following a phylogenomic approach based on a set of conserved single-copy proteins. In addition to breaking up parap ...

(GTDB). In addition to these species with published names, several non-validly published species (‘Bacillus dabaoshanensis', ‘Bacillus dafuensis’, ‘Bacillus massiliogabonensis’, and ‘Bacillus mesophilum') been observed to branch with other ''Cytobacillus'' species and share molecular markers (in the form of

) exclusively unique for this genus. However the lack of culture strain information prevented the transfer of these species into the genus. It is important to note as genome and strain information becomes available, it is necessary to conduct additional analyses of these classifications to account for any required amendments.

References

{{Taxonbar, from=Q107105214 Bacillaceae Bacteria genera