''Ectobacillus'' is a genus 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 ...

(with the exception of ''Ectobacillus funiculus'', which is

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

), rod-shaped bacteria 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 ''Ectobacillus panaciterrae.'' ''Ectobacillus'' is composed of species originally belonging to the genus ''

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 ...

''. The genus ''Bacillus'' comprises a large number of phylogenetically unrelated bacteria species with a diverse range of biochemical characteristics. The polyphyletic nature of the genus is partly due to the vague criteria used to assign species to this genus (ie. accepting all species that are able to form endospores in aerobic conditions). Comparative genomic analyses and phylogenetic studies have set out to clarify the complex taxonomic relationship of this genus, resulting in the transfer of many species into novel genera such as ''

Virgibacillus ''Virgibacillus'' is a genus of Gram-positive, rod-shaped (bacillus) bacteria and a member of the phylum Bacillota. ''Virgibacillus'' species can be obligate aerobes (oxygen reliant), or facultative anaerobes and catalase enzyme positive. Under s ...

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'' f ...

Brevibacillus ''Brevibacillus'' is a genus of Gram-positive bacteria in the family Paenibacillaceae The Paenibacillaceae are a family of Gram-positive bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often con ...

'' and ''

Alteribacter ''Alteribacter'' is a genus of Gram-positive or Gram-variable, rod-shaped bacteria in the family ''Bacillaceae'' within the order ''Bacillales''. The type species for this genus is ''Alteribacter auranticus.'' ''Alteribacter'' is composed of spe ...

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

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 ...

'' 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 ''Ectobacillus'' is derived from its taxonomic position in relation to ''Bacillus''. The prefix "ecto-" (which comes from the Greek preposition ''ecto'', and translates to "outside") and the suffix "-bacillus" (which comes from the Latin noun ''Bacillus'', referring to a rod or small staff, as well as ''Bacillus'', a bacterial genus) come together to form the name ''Ectobacillus,'' meaning "outside of ''Bacillus''".

Biochemical Characteristics and Molecular Signatures

Members of the genus ''Ectobacillus'' can be

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' ...

. They all are endospore-forming and some members are motile cells. ''Ectobacillus'' can survive in temperatures ranging from 15°C to 45°C, but optimal growth occurs in the range of 28-35°C. Analyses of genome sequences from ''Ectobacillus'' have identified five

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 are exclusive for ''Ectobacillus'' species in the proteins 3-isopropylmalate dehydratase small subunit, bacillithiol biosynthesis deacetylase BshB1, aldo or keto reductase, MBL fold metallo-hydrolase, and CYTH domain-containing protein. These CSIs can be used to demarcate ''Ectobacillus'' from other ''Bacillceae'' genera in molecular terms.

Taxonomy

As of May 2021, there are a total of 4 species with validly published names in the genus ''Ectobacillus''. Members of this clade were found to group together in a monophyletic branch in various phylogenetic trees constructed on conserved genome sequences and 16S rRNA sequences. This branching pattern could also be seen 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), further supporting this classification.

References

{{Taxonbar, from=Q107210939 Bacillaceae Bacteria genera