Bacillus subtilis
| Bacillus subtilis | |
|---|---|
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| TEM micrograph of a B. subtilis cell in cross-section (scale bar = 200 nm). | |
| Scientific classification | |
| Domain: | Bacteria |
| Phylum: | Firmicutes |
| Class: | Bacilli |
| Order: | Bacillales |
| Family: | Bacillaceae |
| Genus: | Bacillus |
| Species: | B. subtilis |
| Binomial name | |
| Bacillus subtilis (Ehrenberg 1835) Cohn 1872 |
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| Synonyms | |
Bacillus subtilis, known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium commonly found in soil.[3] A member of the genus Bacillus, B. subtilis is rod-shaped, and has the ability to form a tough, protective endospore, allowing the organism to tolerate extreme environmental conditions. Unlike several other well-known species, B. subtilis has historically been classified as an obligate aerobe, though recent research has demonstrated that this is not strictly correct.[4]
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[edit] Pathogenesis
B. subtilis is only known to cause disease in severely immunocompromised patients, and can conversely be used as a probiotic in healthy individuals[5]. It may contaminate food but rarely causes food poisoning.[6] B. subtilis produces the proteolytic enzyme subtilisin. B. subtilis spores can survive the extreme heat during cooking. B. subtilis is responsible for causing ropiness — a sticky, stringy consistency caused by bacterial production of long-chain polysaccharides — in spoiled bread dough.
[edit] Reproduction
B. subtilis can divide symmetrically to make two daughter cells (binary fission), or asymmetrically, producing a single endospore that can remain viable for decades and is resistant to unfavourable environmental conditions such as draught, salinity, extreme pH, radiation and solvents. The endospore is formed at times of nutritional stress, allowing the organism to persist in the environment until conditions become favorable. Prior to the process of sporulation the cells might become motile by producing flagella, take up DNA from the environment, or produce antibiotics. These responses are viewed as attempts to seek out nutrients by seeking a more favourable environment, enabling the cell to make use of new beneficial genetic material or simply by killing of competition.
[edit] Chromosomal replication
B. subtilis is a model organism used to study bacterial chromosome replication. Replication of the single circular chromosome initiates at a single locus, the origin (oriC). Replication proceeds bidirectionally and two replication forks progress in clockwise and counterclockwise directions along the chromosome. Chromosome replication is completed when the forks reach the terminus region, which is positioned opposite to the origin on the chromosome map. The terminus region contains several short DNA sequences (Ter sites) that promote replication arrest. Specific proteins mediate all the steps in DNA replication. Comparison between the proteins involved in chromosomal DNA replication in B. subtilis and in Escherichia coli reveals similarities and differences. Although the basic components promoting initiation, elongation, and termination of replication are well-conserved, some important differences can be found (such as one bacterium missing proteins essential in the other). These differences underline the diversity in the mechanisms and strategies that various bacterial species have adopted to carry out the duplication of their genomes.[7] Bacillisc
[edit] Model organism
B. subtilis has proven highly amenable to genetic manipulation, and has become widely adopted as a model organism for laboratory studies, especially of sporulation, which is a simplified example of cellular differentiation. It is also heavily flagellated, which gives B. subtilis the ability to move quickly in liquids. In terms of popularity as a laboratory model organism, B. subtilis is often used as the Gram-positive equivalent of Escherichia coli, an extensively studied Gram-negative bacterium.
Wild-type natural isolates of B. subtilis are difficult to work with compared to laboratory strains that have undergone domestication processes of mutagenesis and selection. These strains often have improved capabilities of transformation (uptake and integration of environmental DNA), growth, and loss of abilities needed "in the wild." And, while dozens of different strains fitting this description exist, the strain designated 168 is the most widely used.
[edit] Uses
B. subtilis is used as a soil inoculant in horticulture and agriculture. B. globigii, a closely related but phylogenetically distinct species[8][9] was used as a biowarfare simulant during Project SHAD (aka Project 112).[10][dead link]
Enzymes produced by B. subtilis and B. licheniformis are widely used as additives in laundry detergents.
Its other uses include:
- A strain of B. subtilis formerly known as Bacillus natto is used in the commercial production of the Japanese food natto, as well as the similar Korean food cheonggukjang.
- B. subtilis strain QST 713 (marketed as QST 713 or Serenade) has a natural fungicidal activity, and is employed as a biological control agent.
- It was popular worldwide before the introduction of consumer antibiotics as an immunostimulatory agent to aid treatment of gastrointestinal and urinary tract diseases. It is still widely used in Western Europe and the Middle East as an alternative medicine
- It can convert (decompose) some explosives into harmless compounds of nitrogen, carbon dioxide, and water.
- Its surface binding properties play a role in safe radionuclide waste [e.g. thorium (IV) and plutonium (IV)] disposal.
- Recombinant strains pBE2C1 and pBE2C1AB were used in production of polyhydroxyalkanoates (PHA), and malt waste can be used as their carbon source for lower cost PHA production.
- It is used to produce amylase.
- It is used to produce hyaluronic acid,[11] which is useful in the joint-care sector in healthcare.
- It may provide some benefit to saffron growers by speeding corm growth and increasing stigma biomass yield.[12]
[edit] Genome
B. subtilis has approximately 4,100 genes. Of these, only 192 were shown to be indispensable; another 79 were predicted to be essential as well. A vast majority of essential genes were categorized in relatively few domains of cell metabolism, with about half involved in information processing, one-fifth involved in the synthesis of cell envelope and the determination of cell shape and division, and one-tenth related to cell energetics.[13]
Several non-coding RNAs have been characterized in the B. subtilis genome, including Bsr RNAs.[14]
[edit] History
In 1835, the bacterium was originally named Vibrio subtilis by Christian Gottfried Ehrenberg,[15] and renamed Bacillus subtilis by Ferdinand Cohn in 1872.[16] Cultures of B. subtilis were used throughout the 1950s as an alternative medicine due to the immunostimulatory effects of its cell matter, which upon digestion has been found to significantly stimulate broad spectrum immune activity including activation of specific antibody IgM, IgG and IgA secretion[17] and release of CpG dinucleotides inducing INF A/Y producing activity of leukocytes and cytokines important in the development of cytotoxicity towards tumor cells.[18] It was marketed throughout America and Europe from 1946 as an immunostimulatory aid in the treatment of gut and urinary tract diseases such as Rotavirus and Shigella,[19] but declined in popularity after the introduction of cheap consumer antibiotics, despite causing less chance of allergic reaction and significantly lower toxicity to normal gut flora.
[edit] See also
[edit] References
- ^ Euzéby JP (2008). "Bacillus". List of Prokaryotic names with Standing in Nomenclature. http://www.bacterio.cict.fr/b/bacillus.html. Retrieved 2008-11-18.
- ^ Ambrosiano N (1999-06-30). "Lab biodetector tests to be safe, public to be well informed". Press release. Los Alamos National Labs. http://www.lanl.gov/news/releases/archive/99-101.shtml. Retrieved 2008-11-18.
- ^ Madigan M, Martinko J (editors). (2005). Brock Biology of Microorganisms (11th ed.). Prentice Hall. ISBN 0-13-144329-1.
- ^ Nakano MM, Zuber P (1998). "Anaerobic growth of a "strict aerobe" (Bacillus subtilis)". Annu Rev Microbiol 52: 165–190. doi:10.1146/annurev.micro.52.1.165. PMID 9891797.
- ^ http://jcm.asm.org/content/36/1/325.full
- ^ Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
- ^ Noirot P (2007). "Replication of the Bacillus subtilis chromosome". In Graumann P. Bacillus: Cellular and Molecular Biology. Caister Academic Press. ISBN 978-1-904455-12-7. http://www.horizonpress.com/bac.
- ^ Nakamura LK (1979). "Taxonomic relationship of Black-Pigmented Bacillus subtilis strains and a Proposal for Bacillus atrophaeus sp. nov". Int. J. Syst. Bacteriol. 39 (3): 295–300. doi:10.1099/00207713-39-3-295. http://ijs.sgmjournals.org/cgi/content/abstract/39/3/295.
- ^ Burke SA, Wright JD, Robinson MK, Bronk BV, Warren RL (May 2004). "Detection of molecular diversity in Bacillus atrophaeus by amplified fragment length polymorphism analysis". Appl. Environ. Microbiol. 70 (5): 2786–2790. doi:10.1128/AEM.70.5.2786-2790.2004. PMC 404429. PMID 15128533. http://aem.asm.org/cgi/pmidlookup?view=long&pmid=15128533.
- ^ http://www1.va.gov/shad/[dead link]
- ^ http://www.biopharma.novozymes.com/en/products---technologies/hyaluronic-acid/hyacare.aspx
- ^ Sharaf-Eldin M, Elkholy S, Fernández JA, Junge H, Cheetham R, Guardiola J, Weathers P"Bacillus subtilis FZB24(R) Affects Flower Quantity and Quality of Saffron (Crocus sativus)." Planta Med. 2008 Jul 11;
- ^ Kobayashi K, Ehrlich SD, Albertini A, Amati G, Andersen KK, Arnaud M, Asai K, Ashikaga S, Aymerich S, Bessieres P, Boland F, Brignell SC, Bron S, Bunai K, Chapuis J, Christiansen LC, Danchin A, Débarbouille M, Dervyn E, Deuerling E, Devine K, Devine SK, Dreesen O, Errington J, Fillinger S, Foster SJ, Fujita Y, Galizzi A, Gardan R, Eschevins C, Fukushima T, Haga K, Harwood CR, Hecker M, Hosoya D, Hullo MF, Kakeshita H, Karamata D, Kasahara Y, Kawamura F, Koga K, Koski P, Kuwana R, Imamura D, Ishimaru M, Ishikawa S, Ishio I, Le Coq D, Masson A, Mauël C, Meima R, Mellado RP, Moir A, Moriya S, Nagakawa E, Nanamiya H, Nakai S, Nygaard P, Ogura M, Ohanan T, O'Reilly M, O'Rourke M, Pragai Z, Pooley HM, Rapoport G, Rawlins JP, Rivas LA, Rivolta C, Sadaie A, Sadaie Y, Sarvas M, Sato T, Saxild HH, Scanlan E, Schumann W, Seegers JF, Sekiguchi J, Sekowska A, Séror SJ, Simon M, Stragier P, Studer R, Takamatsu H, Tanaka T, Takeuchi M, Thomaides HB, Vagner V, van Dijl JM, Watabe K, Wipat A, Yamamoto H, Yamamoto M, Yamamoto Y, Yamane K, Yata K, Yoshida K, Yoshikawa H, Zuber U, Ogasawara N. (2003). "Essential Bacillus subtilis genes". PNAS 100 (8): 4678–83. PMID 12682299.
- ^ Saito S, Kakeshita H, Nakamura K (2008). "Novel small RNA-encoding genes in the intergenic regions of Bacillus subtilis". Gene 428 (1–2): 2–8. doi:10.1016/j.gene.2008.09.024. PMID 18948176.
- ^ Ehrenberg CG (1835). Physikalische Abhandlungen der Koeniglichen Akademie der Wissenschaften zu Berlin aus den Jahren 1833–1835. pp. 145–336.
- ^ Cohn F (1872). "Untersuchungen über Bacterien". Beitr Biol Pflanzen 1 (Heft 1): 127–224.
- ^ Ciprandi, G., A. Scordamaglia, D. Venuti, M. Caria, and G. W. Canonica. (1986). "In vitro effects of Bacillus subtilis on the immune response". Chemioterapia 5 (6): 404–7. PMID 3100070.
- ^ Shylakhovenko, V.A. (June 2003). "Anticancer and Immunostimulatory effects of Nucleoprotein Fraction of Bacillus subtilis". Experimental Oncology 25: 119–123.
- ^ Mazza, P. (1994). "The use of Bacillus subtilis as an antidiarrhoeal microorganism". Boll. Chim. Farm. 133 (1): 3–18. PMID 8166962.
[edit] External links
- SubtiWiki: SubtiWiki "up-to-date information for all genes of Bacillus subtilis"
- http://epa.gov/biotech_rule/pubs/fra/fra009.htm
