''Siminovitchia'' 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. The Gram stain is ...

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

rod-shaped bacteria Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea ...

in the family ''

Bacillaceae Bacillaceae, from Latin "bacillus", meaning "little staff, wand", 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 Baci ...

'' from the order ''

Bacillales Bacillales, from Latin "bacillus", meaning "little staff, wand", are an order (biology), order of Gram-positive bacteria, placed within the Bacillota. The ''Bacillales'' are the most productive order of the phylum ''Firmicutes''. Representative ...

.'' The type species of this genus is ''Siminovitchia fortii.'' Members of ''Siminovitchia'' are previously species belonging to ''

Bacillus ''Bacillus'', from Latin "bacillus", meaning "little staff, wand", 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-sh ...

'', a genus that has been recognized as displaying extensive

polyphyly A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as homoplasies, which ar ...

and phylogenetic heterogeneity due to the vague criteria (such as the ability to form

endospore An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form (''endo'' means 'within'), but it is not a true spore (i.e., not ...

s in the presence of oxygen) previously used to assign species to this clade. Multiple studies using comparative phylogenetic analyses have been published in an attempt to clarify the evolutionary relationships between ''Bacillus'' species, resulting in the establishment of numerous 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 sp ...

'', ''

Brevibacillus ''Brevibacillus'' is a genus of Gram-positive bacteria in the family Brevibacillaceae. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnolo ...

, Solibacillus'', ''

Alicyclobacillus ''Alicyclobacillus'' is a genus of Gram-variable, rod-shaped, spore-forming bacteria. The bacteria are able to grow in acidic conditions, while the spores are able to survive typical pasteurization procedures. Overview ''Alicyclobacilli'' are ...

,'' '' Virgibacillus'' and ''

Evansella ''Evansella'' is a genus of Gram-positive bacteria, 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 t ...

''. In addition, the genus ''Bacillus'' has been restricted to 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 ''Bacill ...

'' and ''

Bacillus cereus ''Bacillus cereus'' is a Gram-positive bacteria, Gram-positive Bacillus, 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 o ...

.'' The name ''Siminovitchia'' was named after the Canadian geneticist Professor Louis Siminovitch (

University of Toronto The University of Toronto (UToronto or U of T) is a public university, public research university whose main campus is located on the grounds that surround Queen's Park (Toronto), Queen's Park in Toronto, Ontario, Canada. It was founded by ...

), for his work on the discovery of bacteriophage lysogeny and for his seminal contributions on advancement of the field of

Medical Genetics Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to me ...

in Canada.

Biochemical Characteristics and Molecular Signatures

Members of this genus are

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 ...

and found in locations such as soil and dairy farms. All members can produce endospores and most are motile by means of peritrichous

flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

. Members are generally

catalase Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting ...

and

oxidase positive The oxidase test is used to determine whether an organism possesses the cytochrome c oxidase enzyme. The test is used as an aid for the differentiation of '' Neisseria'', '' Moraxella'', '' Campylobacter'' and '' Pasteurella'' species (oxidase posi ...

. The optimal growth conditions for ''Siminovitchia'' occur in the temperature range 30-37 °C and at pH 6.0–8.0. Analyses of ''Siminovitchia'' genome sequences identified seven

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) for this genus in the proteins DNA repair protein RecN, amidophosphoribosyltransferase, UDP-N-acetylmuramate dehydrogenase, 50S ribosomal protein L11 methyltransferase, iron-sulphur cluster-binding protein and alanine racemase, which in most cases are exclusively shared by either all or most members of this genus. These molecular signatures serve as identifying characteristics for this genus and provide a method to reliably differentiate them from other ''Bacillaceae'' genera and bacteria.

Taxonomy

''Siminovitchia'', as of May 2021, contains a total of 8 species with validly published names. This genus was identified as a

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

clade and phylogenetically unrelated to other ''Bacillus'' species in studies examining the taxonomic relationships within ''Bacillus''. 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 resolving parap ...

(GTDB). One non-validly published species, "Bacillus freudenreichii", is also found to group with other members of ''Siminovitchia'' in phylogenetic trees as well as share the same molecular markers in the form of

(CSIs). However, its transfer was not officially proposed due to the lack of culture strain information. Further revision of this genus is required as additional genomes and novel species are discovered and assigned.

Phylogeny

References

{{Taxonbar, from=Q107210967 Bacillaceae Bacteria genera

Biochemical Characteristics and Molecular Signatures

Taxonomy

Phylogeny

See also

References