''Bacillus'', from

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

"bacillus", meaning "little staff, wand", is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

, a member of the phylum ''

Bacillota The Bacillota (synonym Firmicutes) are a phylum of bacteria, most of which have Gram-positive cell wall structure. They have round cells, called cocci (singular coccus), or rod-like forms (bacillus). A few Bacillota, such as '' Megasphaera'', ...

'', with 266 named

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural ''Bacilli'' is the name of the

class Class, Classes, or The Class may refer to: Common uses not otherwise categorized * Class (biology), a taxonomic rank * Class (knowledge representation), a collection of individuals or objects * Class (philosophy), an analytical concept used d ...

of bacteria to which this genus belongs. ''Bacillus'' species can be either obligate aerobes which are dependent on

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

, or facultative anaerobes which can survive in the absence of oxygen. Cultured ''Bacillus'' species test positive for the

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

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 ...

if oxygen has been used or is present. ''Bacillus'' can reduce themselves to oval

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 and can remain in this dormant state for years. The endospore of one species from Morocco is reported to have survived being heated to 420 °C. Endospore formation is usually triggered by a lack of nutrients: the bacterium divides within its cell wall, and one side then engulfs the other. They are not true

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s (i.e., not an offspring). Endospore formation originally defined the genus, but not all such species are closely related, and many species have been moved to other genera of the ''Bacillota''. Only one endospore is formed per cell. The spores are resistant to heat, cold, radiation, desiccation, and disinfectants. ''Bacillus anthracis'' needs oxygen to sporulate; this constraint has important consequences for epidemiology and control. In vivo, ''B. anthracis'' produces a polypeptide (polyglutamic acid) capsule that kills it from phagocytosis. The genera ''Bacillus'' and ''Clostridium'' constitute the family ''Bacillaceae''. Species are identified by using morphologic and biochemical criteria. Because the spores of many ''Bacillus'' species are resistant to heat, radiation, disinfectants, and desiccation, they are difficult to eliminate from medical and pharmaceutical materials and are a frequent cause of contamination. Not only are they resistant to heat, radiation, etc., but they are also resistant to chemicals such as antibiotics. This resistance allows them to survive for many years and especially in a controlled environment. ''Bacillus'' species are well known in the food industries as troublesome spoilage organisms. Ubiquitous in nature, ''Bacillus'' includes

symbiotic Symbiosis (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

(sometimes referred to as

endophyte An endophyte is an endosymbiont, often a bacterium or fungus, that lives within a plant for at least part of its life cycle without causing apparent disease. Endophytes are ubiquitous and have been found in all species of plants studied to date; ...

s) as well as independent species. Two species are medically significant: '' B. anthracis'' causes

anthrax Anthrax is an infection caused by the bacterium '' Bacillus anthracis'' or ''Bacillus cereus'' biovar ''anthracis''. Infection typically occurs by contact with the skin, inhalation, or intestinal absorption. Symptom onset occurs between one ...

; and '' B. cereus'' causes

food poisoning Foodborne illness (also known as foodborne disease and food poisoning) is any illness resulting from the contamination of food by pathogenic bacteria, viruses, or parasites, as well as prions (the agents of mad cow disease), and toxins such ...

. Many species of ''Bacillus'' can produce copious amounts of enzymes, which are used in various industries, such as in the production of

alpha amylase Alpha (uppercase , lowercase ) is the first letter of the Greek alphabet. In the system of Greek numerals, it has a value of one. Alpha is derived from the Phoenician letter ''aleph'' , whose name comes from the West Semitic word for ' o ...

used in starch hydrolysis and the

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...

subtilisin Subtilisin is a protease (a protein-digesting enzyme) initially obtained from ''Bacillus subtilis''. Subtilisins belong to subtilases, a group of serine proteases that – like all serine proteases – initiate the nucleophilic attack on the ...

used in

detergent A detergent is a surfactant or a mixture of surfactants with Cleanliness, cleansing properties when in Concentration, dilute Solution (chemistry), solutions. There are a large variety of detergents. A common family is the alkylbenzene sulfonate ...

s. '' B. subtilis'' is a valuable model for bacterial research. Some ''Bacillus'' species can synthesize and secrete

lipopeptide A lipopeptide is a molecule consisting of a lipid connected to a peptide. They are able to self-assemble into different structures. Many bacteria produce these molecules as a part of their metabolism, especially those of the genus ''Bacillus'', ...

s, in particular

surfactin Surfactin is a cyclic lipopeptide, commonly used as an antibiotic for its capacity as a surfactant. It is an amphiphile capable of withstanding hydrophilic and hydrophobic environments. The Gram-positive bacterial species ''Bacillus subtilis' ...

s and

mycosubtilin Mycosubtilin is a natural lipopeptide with antifungal and hemolytic activities and isolated from ''Bacillus'' species. It belongs to the iturin lipopeptide family. Definition Mycosubtilin is a natural lipopeptide. It is produced by the strain ...

s. ''Bacillus'' species are also found in marine

sponge Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and a ...

s. Marine sponge associated ''Bacillus subtilis'' (strains WS1A and YBS29) can synthesize several antimicrobial peptides. These ''Bacillus subtilis'' strains can develop disease resistance in ''

Labeo rohita The rohu, rui, ruhi or roho labeo (''Labeo rohita'') is a species of fish of the carp family, found in rivers in South Asia. It is a large omnivore and extensively used in aquaculture. Description The rohu is a large, silver-colored fish o ...

''.

Structure

Cell wall

The cell wall of ''Bacillus'' is a structure on the outside of the cell that forms the second barrier between the bacterium and the environment, and at the same time maintains the rod shape and withstands the pressure generated by the cell's

turgor Turgor pressure is the force within the cell that pushes the plasma membrane against the cell wall. It is also called ''hydrostatic pressure'', and is defined as the pressure in a fluid measured at a certain point within itself when at equilib ...

. The cell wall is made of teichoic and teichuronic acids. ''B. subtilis'' is the first bacterium for which the role of an

actin Actin is a family of globular multi-functional proteins that form microfilaments in the cytoskeleton, and the thin filaments in muscle fibrils. It is found in essentially all eukaryotic cells, where it may be present at a concentration of ...

-like

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is compos ...

in cell shape determination and

peptidoglycan Peptidoglycan or murein is a unique large macromolecule, a polysaccharide, consisting of sugars and amino acids that forms a mesh-like layer (sacculus) that surrounds the bacterial cytoplasmic membrane. The sugar component consists of alternating ...

synthesis was identified and for which the entire set of peptidoglycan-synthesizing enzymes was localized. The role of the cytoskeleton in shape generation and maintenance is important. ''Bacillus'' species are rod-shaped, endospore-forming aerobic or facultatively anaerobic, Gram-positive bacteria; in some species cultures may turn Gram-negative with age. The many species of the genus exhibit a wide range of physiologic abilities that allow them to live in every natural environment. Only one endospore is formed per cell. The spores are resistant to heat, cold, radiation, desiccation, and disinfectants.

Origin of name

The genus ''Bacillus'' was named in 1835 by

Christian Gottfried Ehrenberg Christian Gottfried Ehrenberg (19 April 1795 – 27 June 1876) was a German Natural history, naturalist, zoologist, Botany, botanist, comparative anatomist, geologist, and microscopy, microscopist. He is considered to be one of the most famous an ...

, to contain rod-shaped (bacillus) bacteria. He had seven years earlier named the genus ''

Bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

''. ''Bacillus'' was later amended by

Ferdinand Cohn Ferdinand Julius Cohn (24 January 1828 – 25 June 1898) was a German biologist. He is one of the founders of modern bacteriology and microbiology. Biography Ferdinand Julius Cohn was born in the Jewish quarter of Breslau in the Prussian Pro ...

to further describe them as spore-forming, Gram-positive, aerobic or facultatively anaerobic bacteria. Like other genera associated with the early history of microbiology, such as ''

Pseudomonas ''Pseudomonas'' is a genus of Gram-negative bacteria belonging to the family Pseudomonadaceae in the class Gammaproteobacteria. The 348 members of the genus demonstrate a great deal of metabolic diversity and consequently are able to colonize a ...

'' and ''

Vibrio ''Vibrio'' is a genus of Gram-negative bacteria, which have a characteristic curved-rod (comma) shape, several species of which can cause foodborne infection or soft-tissue infection called Vibriosis. Infection is commonly associated with eati ...

'', the 266 species of ''Bacillus'' are ubiquitous. The genus has a very large

ribosomal Ribosomes () are macromolecular machines, found within all cells, that perform biological protein synthesis (messenger RNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA molecules to fo ...

16S diversity.

Isolation and identification

Established methods for isolating ''Bacillus'' species for culture primarily involve suspension of sampled soil in distilled water, heat shock to kill off vegetative cells leaving primarily viable spores in the sample, and culturing on agar plates with further tests to confirm the identity of the cultured colonies. Additionally, colonies which exhibit characteristics typical of ''Bacillus'' bacteria can be selected from a culture of an environmental sample which has been significantly diluted following heat shock or hot air drying to select potential ''Bacillus'' bacteria for testing. Cultured colonies are usually large, spreading, and irregularly shaped. Under the microscope, the ''Bacillus'' cells appear as rods, and a substantial portion of the cells usually contain oval

s at one end, making them bulge.

Characteristics of ''Bacillus'' spp.

S.I. Paul et al. (2021) isolated and identified multiple strains of ''

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 ...

'' (strains WS1A, YBS29, KSP163A, OA122, ISP161A, OI6, WS11, KSP151E, and S8,) from marine sponges of the Saint Martin's Island Area of the

Bay of Bengal The Bay of Bengal is the northeastern part of the Indian Ocean. Geographically it is positioned between the Indian subcontinent and the Mainland Southeast Asia, Indochinese peninsula, located below the Bengal region. Many South Asian and Southe ...

Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...

. Based on their study, colony, morphological, physiological, and biochemical characteristics of ''Bacillus'' spp. are shown in the Table below. Note: + = Positive, – =Negative, O= Oxidative, F= Fermentative

Phylogeny

It's been long known that the (pre-2020) definition of ''Bacillus'' is overly vague. * Xu and Côté (2003) uses 16S and ITS rRNA regions to divide the genus ''Bacillus'' into 10 groups, including the nested genera '' Paenibacillus'', ''

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 ...

'', '' Geobacillus'', ''Marinibacillus'' and '' Virgibacillus''. * Ash and Carol (2008) also uses 16S rRNA and found extensive "phylogenetic heterogenity". * 'The All-Species Living Tree' Project, which has been in operation since 2008, also maintains a 16S (and 23S if available) tree of all validated species. In this tree, the genus ''Bacillus'' contains a very large number of nested taxa and majorly in both 16S and 23S. It is

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

to the

Lactobacillales Lactobacillales are an order of gram-positive, low-GC, acid-tolerant, generally nonsporulating, nonrespiring, either rod-shaped (bacilli) or spherical ( cocci) bacteria that share common metabolic and physiological characteristics. These bac ...

(''Lactobacillus, Streptococcus, Staphylococcus, Listeria'', etc.), due to '' Bacillus coahuilensis'' and others. * Alcaraz ''et al.'' 2010 presents a gene

concatenation In formal language theory and computer programming, string concatenation is the operation of joining character strings end-to-end. For example, the concatenation of "snow" and "ball" is "snowball". In certain formalizations of concatenati ...

study, which found results similar to the All-Species Living Tree, but with a much more limited number of species in terms of groups. (This scheme used ''Listeria'' as an outgroup, so in light of the ARB tree, it may be "inside-out"). * Gupta ''et al.'' 2020 and Patel ''et al.'' 2020 use phylogenomics and

comparative genomics Comparative genomics is a branch of biological research that examines genome sequences across a spectrum of species, spanning from humans and mice to a diverse array of organisms from bacteria to chimpanzees. This large-scale holistic approach c ...

to resolve the structure in ''Bacillus'' sensu lato. They propose (and validly publish) a number of new genus names, thereby restricting ''Bacillus'' has been restricted to only include species closely related to ''

'' 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 ...

.'' (This does not make the genus monophyletic, however: a number of nested genera persists between the two groups.) The newly created genera are: '' Peribacillus'', '' Cytobacillus'', '' Mesobacillus'', '' Neobacillus'', '' Metabacillus'', ''

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 ...

'', '' Alteribacter'', '' Ectobacillus'', '' Evansella'', '' Ferdinandcohnia'', '' Gottfriedia'', '' Heyndrickxia'', '' Lederbergia'', '' Litchfieldia'', '' Margalitia'', '' Niallia'', '' Priestia'', '' Robertmurraya'', '' Rossellomorea'', '' Schinkia'', '' Siminovitchia'', '' Sutcliffiella'' and '' Weizmannia''. * Nikolaidis ''et al.'' 2022 studied 1104 ''Bacillus'' proteomes using a gene concatenation based on 114 core proteins and delineated the relationships among the various species, defined as ''Bacillus'' from the NCBI taxonomy. The various strains were clustered into species, based on Average Nucleotide identity (ANI) values, with a species cutoff of 95%. One clade, formed by ''Bacillus anthracis'', ''Bacillus cereus'', ''Bacillus mycoides'', ''Bacillus pseudomycoides'', ''Bacillus thuringiensis'', and ''Bacillus weihenstephanensis'' under the 2011 classification standards, should be a single species (within 97% 16S identity), but for medical reasons, they are considered separate species (an issue also present for four species of ''

Shigella ''Shigella'' is a genus of bacteria that is Gram negative, facultatively anaerobic, non–spore-forming, nonmotile, rod shaped, and is genetically nested within ''Escherichia''. The genus is named after Kiyoshi Shiga, who discovered it in 1 ...

'' and ''

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

'').

Species

Species orphaned and assigned to other

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

: * '' B. Symun'' * '' B. acidicola'' * '' B. acidiproducens'' * '' B. acidocaldarius'' * '' B. acidoterrestris'' * '' B. aeolius'' * '' B. agaradhaerens'' * '' B. agri'' * '' B. aidingensis'' * '' B. akibai'' * '' B. albus'' * '' B. alcalophlus'' * '' B. algicola'' * '' B. alginolyticus'' * '' B. alkalidiazotrophicus'' * '' B. alkalinitrilicus'' * '' B. alkalisediminis'' * '' B. alkalitelluris'' * '' B. alveayuensis'' * '' B. alvei'' * '' B. aminovorans'' * '' B. amylolyticus'' * '' B. andreesenii'' * '' B. aneurinilyticus'' * '' B. anthracis'' * '' B. aquimaris'' * '' B. arenosi'' * '' B. arseniciselenatis'' * '' B. arsenicus'' * '' B. aurantiacus'' * '' B. arvi'' * '' B. aryabhattai'' * '' B. asahii'' * '' B. axarquiensis'' * '' B. azotofixans'' * '' B. azotoformans'' * '' B. badius'' * '' B. barbaricus'' * '' B. bataviensis'' * '' B. beijingensis'' * '' B. benzoevorans'' * '' B. beringensis'' * '' B. berkeleyi'' * '' B. beveridgei'' * '' B. bogoriensis'' * '' B. boroniphilus'' * '' B. borstelensis'' * '' B. brevis'' * '' B. butanolivorans'' * '' B. canaveralius'' * '' B. carboniphilus'' * '' B. cecembensis'' * '' B. cellulosilyticus'' * '' B. centrosporus'' * '' B. cereus'' * '' B. chagannorensis'' * '' B. chitinolyticus'' * '' B. chondroitinus'' * '' B. choshinensis'' * '' B. chungangensis'' * '' B. cibi'' * '' B. circulans'' * '' B. clarkii'' * '' B. clausii'' * '' B. coagulans'' * '' B. coahuilensis'' * '' B. cohnii'' * '' B. composti'' * '' B. curdlanolyticus'' * '' B. cycloheptanicus'' * '' B. cytotoxicus'' * '' B. daliensis'' * '' B. decisifrondis'' * '' B. decolorationis'' * '' B. deserti'' * '' B. dipsosauri'' * '' B. drentensis'' * '' B. edaphicus'' * '' B. ehimensis'' * '' B. eiseniae'' * '' B. enclensis'' * '' B. endophyticus'' * '' B. endoradicis'' * '' B. farraginis'' * '' B. fastidiosus'' * '' B. fengqiuensis'' * '' B. filobacterium rodentuim'' * '' B. firmus'' * '' B. flexus'' * '' B. foraminis'' * '' B. fordii'' * '' B. formosus'' * '' B. fortis'' * '' B. fumarioli'' * '' B. funiculus'' * '' B. fusiformis'' * '' B. gaemokensis'' * '' B. galactophilus'' * '' B. galactosidilyticus'' * '' B. galliciensis'' * '' B. gelatini'' * '' B. gibsonii'' * '' B. ginsengi'' * '' B. ginsengihumi'' * '' B. ginsengisoli'' * '' B. glucanolyticus'' * '' B. gordonae'' * '' B. gottheilii'' * '' B. graminis'' * '' B. halmapalus'' * '' B. haloalkaliphilus'' * '' B. halochares'' * '' B. halodenitrificans'' * '' B. halodurans'' * '' B. halophilus'' * '' B. halosaccharovorans'' * '' B. hemicellulosilyticus'' * '' B. hemicentroti'' * '' B. herbersteinensis'' * '' B. horikoshii'' * '' B. horneckiae'' * '' B. horti'' * '' B. huizhouensis'' * '' B. humi'' * '' B. hwajinpoensis'' * '' B. idriensis'' * '' B. indicus'' * '' B. infantis'' * '' B. infernus'' * '' B. insolitus'' * '' B. invictae'' * '' B. iranensis'' * '' B. isabeliae'' * '' B. isronensis'' * '' B. jeotgali'' * '' B. kaustophilus'' * '' B. kobensis'' * '' B. kochii'' * '' B. kokeshiiformis'' * '' B. koreensis'' * '' B. korlensis'' * '' B. kribbensis'' * '' B. krulwichiae'' * '' B. laevolacticus'' * '' B. larvae'' * '' B. laterosporus'' * '' B. lautus'' * '' B. lehensis'' * '' B. lentus'' * '' B. ligniniphilus'' * '' B. litoralis'' * '' B. locisalis'' * '' B. luciferensis'' * '' B. luteolus'' * '' B. luteus'' * '' B. macauensis'' * '' B. macerans'' * '' B. macquariensis'' * '' B. macyae'' * '' B. malacitensis'' * '' B. mannanilyticus'' * '' B. marisflavi'' * '' B. marismortui'' * '' B. marmarensis'' * '' B. massiliensis'' * '' B. megaterium'' * "'' B. mesentericus''" * '' B. mesonae'' * '' B. methanolicus'' * '' B. methylotrophicus'' * '' B. migulanus'' * '' B. mucilaginosus'' * '' B. muralis'' * '' B. murimartini'' * '' B. mycoides'' * '' B. naganoensis'' * '' B. nanhaiensis'' * '' B. nanhaiisediminis'' * '' B. nealsonii'' * '' B. neidei'' * '' B. neizhouensis'' * '' B. niabensis'' * '' B. niacini'' * '' B. novalis'' * '' B. oceanisediminis'' * '' B. odysseyi'' * '' B. okhensis'' * '' B. okuhidensis'' * '' B. oleronius'' * '' B. oryzaecorticis'' * '' B. oshimensis'' * '' B. pabuli'' * '' B. pakistanensis'' * '' B. pallidus'' * '' B. pallidus'' * '' B. panacisoli'' * '' B. panaciterrae'' * '' B. pantothenticus'' * '' B. parabrevis'' * '' B. paraflexus'' * '' B. pasteurii'' * '' B. patagoniensis'' * '' B. peoriae'' * '' B. persepolensis'' * '' B. persicus'' * '' B. pervagus'' * '' B. plakortidis'' * '' B. pocheonensis'' * '' B. polygoni'' * '' B. polymyxa'' * '' B. popilliae'' * '' B. pseudalcalophilus'' * '' B. pseudofirmus'' * '' B. pseudomycoides'' * '' B. psychrodurans'' * '' B. psychrophilus'' * '' B. psychrosaccharolyticus'' * '' B. psychrotolerans'' * '' B. pulvifaciens'' * '' B. purgationiresistens'' * '' B. pycnus'' * '' B. qingdaonensis'' * '' B. qingshengii'' * '' B. reuszeri'' * '' B. rhizosphaerae'' * '' B. rigui'' * '' B. ruris'' * '' B. salarius'' * '' B. salexigens'' * '' B. saliphilus'' * '' B. schlegelii'' * '' B. sediminis'' * '' B. selenatarsenatis'' * '' B. selenitireducens'' * '' B. seohaeanensis'' * '' B. shacheensis'' * '' B. shackletonii'' * '' B. silvestris'' * '' B. simplex'' * '' B. siralis'' * '' B. smithii'' * '' B. soli'' * '' B. solimangrovi'' * '' B. solisalsi'' * '' B. songklensis'' * '' B. sphaericus'' * '' B. sporothermodurans'' * '' B. stearothermophilus'' * '' B. stratosphericus'' * '' B. subterraneus'' * '' B. taeanensis'' * '' B. thermantarcticus'' * '' B. thermoaerophilus'' * '' B. thermoamylovorans'' * '' B. thermocatenulatus'' * '' B. thermocloacae'' * '' B. thermocopriae'' * '' B. thermodenitrificans'' * '' B. thermoglucosidasius'' * '' B. thermolactis'' * '' B. thermoleovorans'' * '' B. thermophilus'' * '' B. thermoproteolyticus'' * '' B. thermoruber'' * '' B. thermosphaericus'' * '' B. thiaminolyticus'' * '' B. thioparans'' * '' B. thuringiensis'' * '' B. tianshenii'' * '' B. toyonensis'' * '' B. trypoxylicola'' * '' B. tusciae'' * '' B. validus'' * '' B. vedderi'' * '' B. vietnamensis'' * '' B. vireti'' * '' B. vulcani'' * '' B. wakoensis'' * '' B. xiaoxiensis'' * '' B. zanthoxyli'' * '' B. zhanjiangensis''

Ecological and clinical significance

''Bacillus'' species are ubiquitous in nature, e.g. in soil. They can occur in extreme environments such as high pH ('' B. alcalophilus''), high temperature ('' B. thermophilus''), and high salt concentrations ('' B. halodurans''). They also are very commonly found as

s in plants where they can play a critical role in their

immune system The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to bacteria, as well as Tumor immunology, cancer cells, Parasitic worm, parasitic ...

, nutrient absorption and nitrogen fixing capabilities. '' B. thuringiensis'' produces a toxin that can kill insects and thus has been used as

insecticide Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...

. ''B. siamensis'' has antimicrobial compounds that inhibit plant pathogens, such as the fungi '' Rhizoctonia solani'' and ''

Botrytis cinerea ''Botrytis cinerea'' is a necrotrophic fungus that affects many plant species, although its most notable hosts may be wine grapes. In viticulture, it is commonly known as "botrytis bunch rot"; in horticulture, it is usually called "grey mould" ...

'', and they promote plant growth by volatile emissions. Some species of ''Bacillus'' are naturally competent for DNA uptake by transformation. * Two ''Bacillus'' species are medically significant: '' B. anthracis'', which causes

; and '' B. cereus'', which causes

, with symptoms similar to that caused by ''

Staphylococcus ''Staphylococcus'', from Ancient Greek σταφυλή (''staphulḗ''), meaning "bunch of grapes", and (''kókkos''), meaning "kernel" or " Kermes", is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillale ...

''. ** ''B. cereus'' produces toxins which cause two different set of symptoms: *** emetic toxin which can cause vomiting and nausea *** diarrhea * '' B. thuringiensis'' is an important

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

pathogen, and is sometimes used to control insect pests. * ''B. subtilis'' is an important

model organism A model organism is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workings of other organisms. Mo ...

. It is also a notable food spoiler, causing ropiness in bread and related food. ** ''B. subtilis'' can also produce and secrete antibiotics. * Some environmental and commercial strains of '' B. coagulans'' may play a role in food spoilage of highly acidic, tomato-based products.

Industrial significance

Many ''Bacillus'' species are able to secrete large quantities of enzymes. '' Bacillus amyloliquefaciens'' is the source of a natural antibiotic protein barnase (a

ribonuclease Ribonuclease (commonly abbreviated RNase) is a type of nuclease that catalyzes the degradation of RNA into smaller components. Ribonucleases can be divided into endoribonucleases and exoribonucleases, and comprise several sub-classes within th ...

used in starch hydrolysis, the

used with detergents, and the BamH1

restriction enzyme A restriction enzyme, restriction endonuclease, REase, ENase or'' restrictase '' is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. Restriction enzymes are one class o ...

used in DNA research. A portion of the '' Bacillus thuringiensis'' genome was incorporated into

corn Maize (; ''Zea mays''), also known as corn in North American English, is a tall stout Poaceae, grass that produces cereal grain. It was domesticated by indigenous peoples of Mexico, indigenous peoples in southern Mexico about 9,000 years ago ...

and

cotton Cotton (), first recorded in ancient India, is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure ...

crops. The resulting plants are resistant to some insect pests. ''

'' ( natto) is the key microbial participant in the ongoing production of the soya-based traditional natto fermentation, and some ''Bacillus'' species are on the Food and Drug Administration's GRAS (generally regarded as safe) list. The capacity of selected ''Bacillus'' strains to produce and secrete large quantities (20–25 g/L) of extracellular enzymes has placed them among the most important industrial enzyme producers. The ability of different species to ferment in the acid, neutral, and alkaline pH ranges, combined with the presence of thermophiles in the genus, has led to the development of a variety of new commercial enzyme products with the desired temperature, pH activity, and stability properties to address a variety of specific applications. Classical mutation and (or) selection techniques, together with advanced cloning and protein engineering strategies, have been exploited to develop these products. Efforts to produce and secrete high yields of foreign recombinant proteins in ''Bacillus'' hosts initially appeared to be hampered by the degradation of the products by the host proteases. Recent studies have revealed that the slow folding of heterologous proteins at the membrane-cell wall interface of Gram-positive bacteria renders them vulnerable to attack by wall-associated proteases. In addition, the presence of thiol-disulphide oxidoreductases in ''B. subtilis'' may be beneficial in the secretion of disulphide-bond-containing proteins. Such developments from our understanding of the complex protein translocation machinery of Gram-positive bacteria should allow the resolution of current secretion challenges and make ''Bacillus'' species preeminent hosts for heterologous protein production. ''Bacillus'' strains have also been developed and engineered as industrial producers of nucleotides, the vitamin riboflavin, the flavor agent ribose, and the supplement poly-gamma-glutamic acid. With the recent characterization of the genome of ''B. subtilis'' 168 and of some related strains, ''Bacillus'' species are poised to become the preferred hosts for the production of many new and improved products as we move through the genomic and proteomic era.

Use as model organism

'' is one of the best understood prokaryotes, in terms of molecular and cellular biology. Its superb genetic amenability and relatively large size have provided the powerful tools required to investigate a bacterium from all possible aspects. Recent improvements in fluorescent microscopy techniques have provided novel insight into the dynamic structure of a single cell organism. Research on ''B. subtilis'' has been at the forefront of bacterial molecular biology and cytology, and the organism is a model for differentiation, gene/protein regulation, and cell cycle events in bacteria.

References

External links

Bacillus
genomes and related information a
PATRIC
a Bioinformatics Resource Center funded b
NIAID
{{Authority control Bacteria genera Gram-positive bacteria

Structure

Cell wall

Origin of name

Isolation and identification

Characteristics of ''Bacillus'' spp.

Phylogeny

Species

Ecological and clinical significance

Industrial significance

Use as model organism

See also

References

External links