Diferencia entre revisiones de «Bacillus»
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==Phylogeny== |
==Phylogeny== |
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The genus ''Bacillus'' was named in 1835 by [[Christian Gottfried Ehrenberg]], to contain rod-shaped (bacillus) bacteria. He had seven years earlier named the genus ''[[Bacterium]]''. ''Bacillus'' was later amended by [[Ferdinand Cohn]] to further describe them as spore-forming, Gram-positive, aerobic or facultatively anaerobic bacteria.<ref name="Cohn 1872">{{de icon}} Cohn F.: Untersuchungen über Bakterien. Beitrage zur Biologie der Pflanzen Heft 2, 1872, 1, 127-224.</ref> Like other genera associated with the early history of microbiology, such as ''[[Pseudomonas]]'' and ''[[Vibrio]]'', the 266 species of ''Bacillus'' are ubiquitous.<ref>{{lpsn|b/bacillus.html|Bacillus}}</ref>The genus has a very large [[ribosomal]] [[16S ribosomal RNA|16S]] diversity and is environmentally diverse. |
The genus ''Bacillus'' was named in 1835 by [[Christian Gottfried Ehrenberg]], to contain rod-shaped (bacillus) bacteria. He had seven years earlier named the genus ''[[Bacterium]]''. ''Bacillus'' was later amended by [[Ferdinand Cohn]] to further describe them as spore-forming, Gram-positive, aerobic or facultatively anaerobic bacteria.<ref name="Cohn 1872">{{de icon}} Cohn F.: Untersuchungen über Bakterien. Beitrage zur Biologie der Pflanzen Heft 2, 1872, 1, 127-224.</ref> Like other genera associated with the early history of microbiology, such as ''[[Pseudomonas]]'' and ''[[Vibrio]]'', the 266 species of ''Bacillus'' are ubiquitous.<ref>{{lpsn|b/bacillus.html|Bacillus}}</ref>The genus has a very large [[ribosomal]] [[16S ribosomal RNA|16S]] diversity and is environmentally diverse. |
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Several studies have tried to reconstruct the phylogeny of the genus. The ''Bacillus''-specific study with the most diversity covered is by Xu and Cote using 16S and the ITS regions, where they divide the genus into 10 groups, which includes the nested genera ''Paenibacillus, Brevibacillus, Geobacillus, Marinibacillus'' and ''[[Virgibacillus]]''.<ref>{{cite doi|10.1099/Ijs.0.02346-0}}</ref> However, the tree [http://www.arb-silva.de/fileadmin/silva_databases/living_tree/LTP_release_104/LTPs104_SSU_tree.pdf] constructed by [['The All-Species Living Tree' Project|the living tree project]], a collaboration between ARB-Silva and [[LPSN]] where a 16S (and 23S if available) tree of all validated species was constructed,<ref>{{cite doi|10.1016/J.Syapm.2008.07.001}}</ref><ref>{{cite doi|10.1016/j.syapm.2010.08.001}}</ref> the genus ''Bacillus'' contains a very large number of nested taxa and majorly in both 16S and 23S it is paraphyletic to Lactobacillales (''Lactobacillus, Streptococcus, Staphylococcus, Listeria'', etc.), due to ''[[Bacillus coahuilensis]]'' and others. A gene concatenation study found similar results to Xu and Cote, but with a much more limited number of species in terms of groups,<ref name="Alcaraz2010">{{cite doi|10.1186/1471-2164-11-332}}</ref> but used ''Listeria'' as an outgroup, so in light of the ARB tree, it may be "inside-out". |
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One clade, formed by ''B. anthracis'', ''B. cereus'', ''B. mycoides'', ''B. pseudomycoides'', ''B. thuringiensis'', and ''B. weihenstephanensis'' under current classification standards, should be a single species (within 97% 16S identity), but due to medical reasons, they are considered separate species,<ref>Ole Andreas Økstad and Anne-Brit Kolstø [http://link.springer.com/chapter/10.1007%2F978-1-4419-7686-4_2#page-1 Chapter 2: Genomics of Bacillus Species] in M. Wiedmann, W. Zhang (eds.), Genomics of Foodborne Bacterial Pathogens, 29 Food Microbiology and Food Safety. Springer Science+Business Media, LLC 2011 DOI 10.1007/978-1-4419-7686-4_2</ref>{{rp|34–35}} an issue also present for four species of ''[[Shigella]]'' and ''[[Escherichia coli]]''.<ref>BRENNER (D.J.): Family I. Enterobacteriaceae Rahn 1937, Nom. fam. cons. Opin. 15, Jud. Com. 1958, 73; Ewing, Farmer, and Brenner 1980, 674; Judicial Commission 1981, 104. In: N.R. KRIEG and J.G. HOLT (eds), Bergey's Manual of Systematic Bacteriology, first edition, vol. 1, The Williams & Wilkins Co, Baltimore, 1984, pp. 408-420</ref> |
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{{cladogram |
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|title=''Bacillus'' phylogenetics |
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|align=none |
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|caption=Phylogeny of the genus ''Bacillus'' according to <ref name="Alcaraz2010" /> |
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|cladogram={{clade |
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|label1=Root |
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|1={{clade |
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|label1="pathogenic" |
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|1={{clade |
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|1=''[[Bacillus weihenstephanensis]]'' |
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|2=''[[Bacillus cereus]]''/''[[Bacillus thuringiensis|thuringiensis]]''/''[[Bacillus anthracis|anthracis]]'' |
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}} |
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|2={{clade |
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|label1="soil" |
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|1={{clade |
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|1=''[[Bacillus pumilus]]'' |
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|2={{clade |
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|1=''[[Bacillus subtilis]]'' |
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|2=''[[Bacillus licheniformis]]'' |
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}} |
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}} |
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|2={{clade |
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|label1="benthic" |
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|1=''[[Geobacillus kaustophilus]]'' |
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|2={{clade |
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|label1="aquatic" |
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|1={{clade |
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|1={{clade |
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|1=''[[Bacillus coahuilensis]]'' |
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|2=''Bacillus'' sp. m3-13 |
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}} |
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|2=''Bacillus'' sp. NRRLB-14911 |
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}} |
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|2={{clade |
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|label1="benthic" |
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|1=''[[Oceanobacillus iheyensis]]'' |
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|label2="halophiles" |
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|2={{clade |
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|1=''[[Bacillus halodurans]]'' |
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|2=''[[Bacillus clausii]]'' |
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}} |
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}} |
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}} |
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}} |
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}} |
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}} |
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}} |
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}} |
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==See also== |
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* ''[[Paenibacillus]]'' and ''[[Virgibacillus]]'' are genera of bacteria that were formerly included in ''Bacillus'' |
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<!---* "Von bacillus", a genus of bacillus associated with ''Mariquiita mariconae'', widely resistant to machomycin---> |
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Revisión del 19:41 26 ene 2015
Many species of Bacillus can produce copious amounts of enzymes which are made use of in different industries. Some Bacillus species can form intracellular inclusions of polyhydroxyalkanoates under certain adverse environmental conditions, as in a lack of elements such as phosphorus, nitrogen, or oxygen combined with an excessive supply of carbon sources.
B.subtilis has proved a valuable model for research. Other species of Bacillus are important pathogens, causing anthrax and food poisoning.
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), alpha amylase used in starch hydrolysis, the protease subtilisin used with detergents, and the BamH1 restriction enzyme used in DNA research.
A portion of the Bacillus thuringiensis genome was incorporated into corn (and cotton) crops. The resulting GMOs are therefore resistant to some insect pests.
Use as model organism
Bacillus subtilis is one of the best understood prokaryotes, in terms of molecular biology and cell 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 fluorescence microscopy techniques have provided novel and amazing insight into the dynamic structure of a single cell organism. Research on Bacillus 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.[1]
Clinical significance
Two Bacillus species are considered medically significant: B. anthracis, which causes anthrax, and B. cereus, which causes food poisoning similar to that caused by Staphylococcus.[2] A third species, B. thuringiensis, is an important insect pathogen, and is sometimes used to control insect pests. The type species is B. subtilis, an important model organism. It is also a notable food spoiler, causing ropiness in bread and related food. Some environmental and commercial strains of B. coagulans may play a role in food spoilage of highly acidic, tomato-based products.
An easy way to isolate Bacillus is by placing nonsterile soil in a test tube with water, shaking, placing in melted mannitol salt agar, and incubating at room temperature for at least a day. 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 endospores at one end, making it bulge.
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. The cell wall is composed of teichoic and teichuronic acids. B. subtilis is the first bacterium for which the role of an actin-like cytoskeleton in cell shape determination and peptidoglycan synthesis was identified, and for which the entire set of peptidoglycan-synthesizing enzymes was localised. The role of the cytoskeleton in shape generation and maintenance is important
Phylogeny
The genus Bacillus was named in 1835 by Christian Gottfried Ehrenberg, to contain rod-shaped (bacillus) bacteria. He had seven years earlier named the genus Bacterium. Bacillus was later amended by Ferdinand Cohn to further describe them as spore-forming, Gram-positive, aerobic or facultatively anaerobic bacteria.[3] Like other genera associated with the early history of microbiology, such as Pseudomonas and Vibrio, the 266 species of Bacillus are ubiquitous.[4]The genus has a very large ribosomal 16S diversity and is environmentally diverse.
Several studies have tried to reconstruct the phylogeny of the genus. The Bacillus-specific study with the most diversity covered is by Xu and Cote using 16S and the ITS regions, where they divide the genus into 10 groups, which includes the nested genera Paenibacillus, Brevibacillus, Geobacillus, Marinibacillus and Virgibacillus.[5] However, the tree [1] constructed by the living tree project, a collaboration between ARB-Silva and LPSN where a 16S (and 23S if available) tree of all validated species was constructed,[6][7] the genus Bacillus contains a very large number of nested taxa and majorly in both 16S and 23S it is paraphyletic to Lactobacillales (Lactobacillus, Streptococcus, Staphylococcus, Listeria, etc.), due to Bacillus coahuilensis and others. A gene concatenation study found similar results to Xu and Cote, but with a much more limited number of species in terms of groups,[8] but used Listeria as an outgroup, so in light of the ARB tree, it may be "inside-out".
One clade, formed by B. anthracis, B. cereus, B. mycoides, B. pseudomycoides, B. thuringiensis, and B. weihenstephanensis under current classification standards, should be a single species (within 97% 16S identity), but due to medical reasons, they are considered separate species,[9]: 34–35 an issue also present for four species of Shigella and Escherichia coli.[10]
See also
- Paenibacillus and Virgibacillus are genera of bacteria that were formerly included in Bacillus
- ↑ Graumann P (editor). (2012). Bacillus: Cellular and Molecular Biology (2nd edición). Caister Academic Press. ISBN 978-1-904455-97-4. [2].
- ↑ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th edición). McGraw Hill. ISBN 0-8385-8529-9.
- ↑ (en alemán) Cohn F.: Untersuchungen über Bakterien. Beitrage zur Biologie der Pflanzen Heft 2, 1872, 1, 127-224.
- ↑ Plantilla:Lpsn
- ↑ Por favor, pon la referencia que aparece aquí.
- ↑ Por favor, pon la referencia que aparece aquí.
- ↑ Por favor, pon la referencia que aparece aquí.
- ↑ Por favor, pon la referencia que aparece aquí.
- ↑ Ole Andreas Økstad and Anne-Brit Kolstø Chapter 2: Genomics of Bacillus Species in M. Wiedmann, W. Zhang (eds.), Genomics of Foodborne Bacterial Pathogens, 29 Food Microbiology and Food Safety. Springer Science+Business Media, LLC 2011 DOI 10.1007/978-1-4419-7686-4_2
- ↑ BRENNER (D.J.): Family I. Enterobacteriaceae Rahn 1937, Nom. fam. cons. Opin. 15, Jud. Com. 1958, 73; Ewing, Farmer, and Brenner 1980, 674; Judicial Commission 1981, 104. In: N.R. KRIEG and J.G. HOLT (eds), Bergey's Manual of Systematic Bacteriology, first edition, vol. 1, The Williams & Wilkins Co, Baltimore, 1984, pp. 408-420