''Litchfieldia'' 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 ...

rod-shaped 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 archae ...

bacteria 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 ...

within 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 for this genus is ''Litchfieldia alkalitelluris.'' ''Litchfieldia'' is composed of species originally belonging to the genus ''

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 displayed 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 ...

due to the vague criteria used to assign new species to the genus. Studies using phylogenetic and comparative genomic analyses have clarified the taxonomy of ''Bacillus'' by restricting the genus 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 ...

'' as well as transfer many species into new novel genera such as '' Virgibacillus, Solibacillus,

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 ...

'' and '' Ectobacillus''. The name ''Litchfieldia'' was named after the American marine microbiologist and ecologist Dr. Carol D. Litchfield (1936-2012).

Biochemical characteristics and molecular signatures

Source: Members of the genus ''Litchfieldia'' 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 ...

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' ...

bacteria. They are all endospore-forming and

motile cells Motility is the ability of an organism to move independently using metabolic energy. This biological concept encompasses movement at various levels, from whole organisms to cells and subcellular components. Motility is observed in animals, mi ...

. They are catalase-positive,

oxidase In biochemistry, an oxidase is an oxidoreductase (any enzyme that catalyzes a redox reaction) that uses dioxygen (O2) as the electron acceptor. In reactions involving donation of a hydrogen atom, oxygen is reduced to water (H2O) or hydrogen peroxid ...

-positive and slightly

halophilic A halophile (from the Greek word for 'salt-loving') is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species. ...

. They can grow in environments containing 0-4% ( w/v)

sodium chloride Sodium chloride , commonly known as Salt#Edible salt, edible salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. It is transparent or translucent, brittle, hygroscopic, and occurs a ...

(NaCl), but grow best in 0-3% (w/v) NaCl. Grow also occurs at (optimally at ) and pH 7.0–10.0 (optimally at pH 8.0–9.0). Analyses of genome sequences from ''Litchfieldia'' species 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 ...

that are unique for the genus ''Litchifieldia'' in the following proteins: MFS transporter, M15 family

metallopeptidase A metalloproteinase, or metalloprotease, is any protease enzyme whose catalytic mechanism involves a metal. An example is ADAM12 which plays a significant role in the fusion of muscle cells during embryo development, in a process known as myoge ...

, amidohydrolase,

response regulator In molecular biology, a response regulator is a protein that mediates a cell's response to changes in its environment as part of a two-component regulatory system. Response regulators are coupled to specific histidine kinases which serve as sens ...

transcription factor, hypothetical proteins, and l-glutamate gamma-semialdehyde dehydrogenase. These molecular signatures provide a reliable way to distinguish members of this genus from other ''Bacillaceae'' genera and bacteria.

Taxonomy

, there are a total of 2 species with validly published names in the genus ''Litchfieldia''. Members of this genus group together to form 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 ...

branch in various

phylogenetic trees A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

constructed based on concatenated sequences from various protein datasets, as well as 16S ribosomal RNA sequences. This branching pattern was also reflected 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 ...

. There is one non-validly published species, ''Bacillus cheonanensis'', that was also found to branch reliably with other members of the ''Litchfieldia'' clade as well as share the unique molecular markers. However, transfer was not proposed for this species due to the lack of culture strain information. Future analyses of this clade should be conducted when additional genome sequence and culture strain information becomes available.

Phylogeny

References

{{Taxonbar, from=Q107210934 Bacillaceae Bacteria genera

Biochemical characteristics and molecular signatures

Taxonomy

Phylogeny

See also

References