''Alkalihalobacillus'' 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 ...
or gram-variable 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 ...
'' from 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 of this genus is ''
Alkalihalobacillus alcalophilus.''
This genus comprises species formerly 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 ...
'', a genus that has been recognized as displaying extensive
polyphyly
A polyphyletic group is an assemblage of organisms or other evolving elements that is of mixed evolutionary origin. The term is often applied to groups that share similar features known as homoplasies, which are explained as a result of converg ...
and phylogenetic heterogeneity due to the vague criteria (such as the ability to form endospores 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'', ''
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'' ...
'', ''
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'' ar ...
'' and ''
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 ...
''.
The genus ''Bacillus'' is now restricted to 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 ''Alkalihalobacillus'' is composed of the prefix "alkali-" (from the Arabic article and noun ''al galiy,'' which translates to 'the ashes of saltwort'), the prefix "halo-" (from the Greek noun ''hals/halos,'' meaning salt) and suffixed by "-bacillus" (from the Latin noun ''bacillus,'' referring to 'a small staff or rod' and ''Bacillus,'' a bacterial genus). Together, the name refers to bacillus living in salty or alkaline conditions, or salty and alkaline conditions.
Taxonomy
This genus, as of May 2021, contains a total of 44 species, 39 of which have been validly published and have established names.
This genus was identified as a
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
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 breaking up parap ...
(GTDB).
Two additional ''Bacillus'' species (''Bacillus alcaliphilum'' and ''Bacillus alkalisoli'') are found to group with other members of ''Alkalihalobacillus'' in phylogenetic trees as well as share the same molecular markers in the form of
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).
However, their 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.
Accepted species
* ''
A. akibai''
* ''
A. alcalophilus''
* ''
A. algicola''
* ''
A. alkalilacus''
* ''
A. alkalinitrilicus''
* ''
A. alkalisediminis''
* ''
A. berkeleyi''
* ''
A. bogoriensis''
* ''
A. caeni''
* ''
A. clausii''
* ''
A. decolorationis''
* ''
A. gibsonii''
* ''
A. halodurans''
* ''
A. hemicellulosilyticus''
* ''
A. hemicentroti''
* ''
A. hunanensis''
* ''
A. hwajinpoensis''
* ''
A. kiskunsagensis''
* ''
A. krulwichiae''
* ''
A. ligniniphilus''
* ''
A. lindianensis''
* ''
A. lonarensis''
* ''
A. macyae''
* ''
A. marmarensis''
* ''
A. miscanthi''
* ''
A. murimartini''
* ''
A. nanhaiisediminis''
* ''
A. oceani''
* ''
A. okhensis''
* ''
A. okuhidensis''
* ''
A. oshimensis''
* ''
A. patagoniensis''
* ''
A. pseudalcaliphilus''
* ''
A. pseudofirmus''
* ''
A. shaceensis''
* ''
A. trypoxylicola''
* ''
A. urbisdiaboli''
* ''
A. wakoensis''
* ''
A. xiaosiensis''
Biochemical characteristics and molecular signatures
Most 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 ...
or
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' ...
and are found in diverse locations such as hypersaline lakes, coastal regions and soil. All species, with the exception of ''Alkalihalobacillus okhensis'', are able to produce
endospores
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., no ...
.
Motility
Motility is the ability of an organism to move independently, using metabolic energy.
Definitions
Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms th ...
is variable, with some species possessing 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 ...
. The majority of species from this genus are
alkaliphilic Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline ( pH roughly 8.5–11) environments, growing optimally around a pH of 10. These bacteria can be further categorized as obligate alkaliphiles (those that require high ...
and
halophilic
The halophiles, named after the Greek word for "salt-loving", are extremophiles that thrive in high salt concentrations. While most halophiles are classified into the domain Archaea, there are also bacterial halophiles and some eukaryotic species, ...
/tolerant, and thus they are able to grow in alkaline conditions, with the optimal growth rate being in the pH range of 9-10 with 1-5% NaCl.
Some species are obligately alkaliphilic and require very alkaline conditions to survive. A wide range of temperature (4-45 °C) can be conducive to growth; however, optimal growth occurs in the range of 25-37°C. Some species are able to produce enzymes such as cellulases and proteases, which are used in laundry detergent manufacturing, xylanases for the pulp paper sector and cyclodextrin glucanotransferase for starch treatment.
In addition, ''
A. clausii'' is
diazotrophic Diazotrophs are bacteria and archaea that fix gaseous nitrogen in the atmosphere into a more usable form such as ammonia.
A diazotroph is a microorganism that is able to grow without external sources of fixed nitrogen. Examples of organisms that d ...
and able to convert atmospheric nitrogen into ammonia and it is also able to produce antimicrobial compounds for the manufacturing of probiotic.
Through genomic analysis, ten CSIs have been identified for this genus in the following proteins: RNase adapter RapZ, flagellar basal body M-ring protein FliF, 7-carboxy-7-deazaguanine synthase QueE, peptide chain release factor 3, type I glutamate-ammonia ligase, tRNA threonyl-carbamoyladenosine dehydratase,
transcription-repair coupling factor, tRNA uridine-5- carboxymethylaminomethyl (34) synthesis enzyme MnmG, 50S ribosomal protein L11 methyltransferase, and
homoserine kinase
In enzymology, a homoserine kinase () is an enzyme that catalyzes the chemical reaction
:ATP + L-homoserine \rightleftharpoons ADP + O-phospho-L-homoserine
Thus, the two substrates of this enzyme are ATP and L-homoserine, whereas its two pro ...
.
These CSIs are specific for ''Alkalihalobacillus'' and provide a novel way to molecularly differentiate this genus from other ''Bacillaceae'' genera and bacteria.
References
{{Taxonbar, from=Q107144877
Bacteria genera
Bacillaceae