''Evansella'' 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 ...

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 ''Evansella cellulosilytica.'' Members of ''Evansella'' was transferred from 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 ...

'', a genus that has long been under close scrutiny by the scientific community due to its inclusion of many phylogenetically unrelated species. The original criteria used to assign species into ''Bacillus'' were vague and applied to many different species of bacteria, resulting in a large genus full of unrelated organisms with a diverse range of biochemical characteristics. To clarify the taxonomic relationships within the genus, multiple phylogenetic studies have been conducted, 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'' ...

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 ...

'' and '' Ectobacillus.'' Additionally, ''Bacillus'' has been restricted only include 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 ''Evansella'' is chosen to celebrate the American microbiologist Dr. Alice Catherine Evans (1885-1975, US Department of Agriculture) in recognition of her contributions to the field of bacteriology.

Biochemical Characteristics and Molecular Signatures

Members of the genus ''Evansella'' 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' ...

. Cells are motile by means of peritrichous

flagella A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...

. They all are endospore-forming and catalase-positive. Species can be found in industrial areas and soda lakes. ''Evansella'' can survive in temperatures ranging from 15°C to 60°C, but optimal growth occurs in the range of 35-40°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 through genomic analyses as exclusive for this genus in the proteins GTP pyrophosphokinase family protein, lipoprotein signal peptidase II and Clp protease ClpP. These CSIs provide a novel means to distinguish ''Evansella'' from other ''Bacillaceae'' genera in molecular terms.

Taxonomy

As of May 2021, there are a total of 5 species with validly published names in the genus ''Evansella''. Various phylogenetic trees created based on concatenated sequences from various datasets of conserved proteins and 16S rRNA genome sequences revealed that members of ''Evansella'' form a monophyletic branch. This clade is also reflected in the branching pattern 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).

References

{{Taxonbar, from=Q107210932 Bacillaceae Bacteria genera