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{{Taxobox
{{Taxobox
| color = lightgrey
| name = ''Bacillus anthracis''
| name = ''Bacillus anthracis''
| image = Bacillus_anthracis_01.png
| image = Bacillus_anthracis.png
| image_width = 240px
| image_width = 240px
| image_caption = Photomicrograph of ''Bacillus anthracis'' (fuchsin-methylene blue spore stain).
| image_caption = Photomicrograph of ''Bacillus anthracis'' (fuchsin-methylene blue spore stain)
| regnum = [[Bacterium|Bacteria]]
| domain = [[Bacterium|Bacteria]]
| kingdom = [[Archaebacteria]]
| phylum = [[Firmicutes]]
| phylum = [[Firmicutes]]
| classis = [[Bacilli]]
| classis = [[Bacilli]]
Line 15: Line 16:
| binomial_authority = Cohn 1872
| binomial_authority = Cohn 1872
}}
}}
[[Image:B_anthracis_diagram_en.png|right|thumb|240px|Structure of ''Bacillus anthracis''.]]
__NOTOC__
{{CMG}}; {{AE}} {{JH}}
==Overview==
'''''Bacillus anthracis''''' is a [[Gram-positive]], [[Facultative anaerobic organism|facultatively anaerobic]], rod-shaped [[bacterium]] of the genus ''[[Bacillus]]''. An [[endospore]] forming bacterium, ''B. anthracis'' is a natural soil-dwelling organism, as well as the causative agent of [[anthrax disease|anthrax]].<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 }}</ref>
Each cell is about 1 by 6 [[micrometre|μm]] in size.
==Historical background==
''B. anthracis'' was the first bacterium conclusively demonstrated to cause disease, by [[Robert Koch]] in 1877.<ref name=Brock>{{cite book | author = Madigan M, Martinko J (editors). | title = Brock Biology of Microorganisms | edition = 11th ed. | publisher = Prentice Hall | year = 2005 | isbn = 0-13-144329-1 }}</ref> The species name ''anthracis'' is from the [[Greek language|Greek]] ''anthrakis'' (ἄνθραξ), meaning ''coal'' and referring to the most common form of the disease, [[cutaneous]] anthrax, in which large black skin [[lesion]]s are formed.
==Pathogenicity==
Under conditions of environmental stress, ''B. anthracis'' bacteria naturally produce endospores which rest in the soil and can survive for decades in this state.  When ingested by a cattle, sheep, or other [[herbivore]]s, the bacteria begin to reproduce inside the animal and eventually kill it, then continue to reproduce in its carcass.  Once the nutrients are exhausted, new endospores are produced and the cycle repeats.<ref name=Baron>{{cite book | author = Turnbull PCB | title = Bacillus. ''In:'' Barron's Medical Microbiology ''(Baron S ''et al'', eds.)| edition = 4th ed. | publisher = Univ of Texas Medical Branch | year = 1996 | url = http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.925 | isbn = 0-9631172-1-1}}</ref>
''B. anthracis'' has at least 89 known [[strain (biology)|strains]], ranging from highly virulent strains with [[biological warfare]] and [[bioterrorism]] applications ([[Ames strain|Ames]] and ''Vollum'') to benign strains used for [[inoculation]]s (''Sterne''). The strains differ in presence and activity of various [[gene]]s, determining their [[virulence]] and production of [[antigen]]s and [[toxin]]s. The form associated with the [[2001 anthrax attacks]] produced both [[anthrax toxin|toxin]] (consisting of three [[protein]]s: [[anthrax toxin|the protective antigen, the edema factor and the lethal factor]]) and a [[Capsule_(microbiology)|capsule]] (consisting of a polymer of glutamic acid).  Infection with anthrax requires the presence of all three of these exotoxins.<ref>{{cite journal |author=Dixon TC, Meselson M, Guillemin J, Hanna PC |title=Anthrax |journal=N. Engl. J. Med. |volume=341 |issue=11 |pages=815-26 |year=1999 |pmid=10477781 |doi=}}</ref>
The bacterium can be cultivated in ordinary nutrient medium under aerobic or anaerobic conditions.
==Treatment==
{{main|Anthrax}}
Infections with ''B. anthracis'' can be treated with [[Beta-lactam|β-lactam]] [[antibiotic]]s such as [[penicillin]], and others which are active against Gram-positive bacteria.<ref>{{cite journal |author = Barnes JM |title=Penicillin and ''B. anthracis''. |journal= J Path Bacteriol |volume=194|year=1947|pages=113}}</ref>
==References==
{{reflist|2}}


==Gallery==
'''''Bacillus anthracis''''' is the [[Etiology|etiologic]] agent of [[anthrax]]—a common disease of livestock and, occasionally, of humans—and the only obligate [[pathogen]] within the genus ''[[Bacillus]]''.<ref name="Spencer">{{cite journal|last=Spencer|first=RC|title=Bacillus anthracis.|journal=Journal of clinical pathology|date=March 2003|volume=56|issue=3|pages=182–7|pmid=12610093|pmc=1769905|doi=10.1136/jcp.56.3.182}}</ref> ''B. anthracis'' is a [[Gram-positive]], [[endospore]]-forming, rod-shaped [[bacterium]], with a width of 1.0–1.2 [[µm]] and a length of 3–5 [[µm]].<ref name="Spencer" /> It can be grown in an ordinary nutrient medium under aerobic or anaerobic conditions.<ref>Holt, J. G., N. R. Krieg, P. H. A. Sneath, J. T. Staley, and S. T. Williams. 1994. Group 17: gram-positive cocci, p. 527–558. In W. R. Hensyl (ed.), Bergey's manual of determinative bacteriology, 9th ed. Williams and Wilkins, Baltimore, Md.</ref>
[[File:Bacillus anthracis belongs to the Bacillus cereus group of strains.png|thumb|''B. anthracis'' belongs to the ''B. cereus'' group of strains.]]
[[Image:B anthracis diagram en.png|thumb|right|thumb|Structure of ''B. anthracis'']]
It is one of few bacteria known to synthesize a protein capsule (poly-D-gamma-glutamic acid). Like ''[[Bordetella pertussis]]'', it forms a [[calmodulin]]-dependent [[adenylate cyclase]] exotoxin known as ([[Anthrax toxin|edema factor]]), along with [[Anthrax lethal factor endopeptidase|lethal factor]]. It bears close [[genotypical]] and [[phenotypical]] resemblance to ''[[Bacillus cereus]]'' and ''[[Bacillus thuringiensis]]''. All three species share cellular dimensions and morphology. All form oval spores located centrally in an unswollen sporangium. ''B. anthracis'' spores, in particular, are highly resilient, surviving extremes of temperature, low-nutrient environments, and harsh chemical treatment over decades or centuries.


<gallery>
The spore is a dehydrated cell with thick walls and additional layers that form inside the cell membrane. It can remain inactive for many years, but if it comes into a favorable environment, it begins to grow again. It is sometimes called an endospore because it initially develops inside the rod-shaped form. Features such as the location within the rod, the size and shape of the endospore, and whether or not it causes the wall of the rod to bulge out are characteristic of particular species of ''Bacillus''. Depending upon the species, the endospores are round, oval, or occasionally cylindrical. They are highly refractile and contain [[dipicolinic acid]]. Electron micrograph sections show they have a thin outer spore coat, a thick spore cortex, and an inner spore membrane surrounding the spore contents. The spores resist heat, drying, and many disinfectants (including 95% ethanol).<ref>Bergey's Manual of Systematic Bacteriology, vol. 2, p. 1105, 1986, Sneath, P.H.A.; Mair, N.S.; Sharpe, M.E.; Holt, J.G. (eds.); Williams & Wilkins, Baltimore, Maryland, USA</ref> Because of these attributes, ''B. anthracis'' spores are extraordinarily well-suited to use (in powdered and aerosol form) as [[biological weapon|biological weapons]]. Such weaponization has been accomplished in the past by at least five state bioweapons programs—those of the [[United Kingdom]], [[Imperial Japan|Japan]], the [[United States]], [[Russia]], and [[Iraq]]—and has been attempted by several others.<ref>Zilinskas, Raymond A. (1999), "Iraq's Biological Warfare Program: The Past as Future?", Chapter 8 in: [[Joshua Lederberg|Lederberg, Joshua]] (editor), ''Biological Weapons: Limiting the Threat'' (1999), [[The MIT Press]], pp 137-158.</ref>


Image: Bacillus_anthracis01.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
== Historical background ==
[[Image:Bacillus anthracis - CapD protein crystal structure.jpg|160px|thumb|CapD protein crystal structure of ''B. anthracis'']]
French physician [[Casimir Davaine]] (1812-1882) demonstrated the symptoms of anthrax were invariably accompanied by the microbe ''B. anthracis''.<ref>{{cite journal
|last=Théodoridès
|first=J
|authorlink=
|date=April 1966
|title=Casimir Davaine (1812-1882): a precursor of Pasteur
|journal=Medical history
|volume=10
|issue=2
|pages=155–65
| publisher = | pmid = 5325873
| bibcode = |pmc=1033586
| doi=10.1017/S0025727300010942
}}</ref>  German physician [[Aloys Pollender]] (1799–1879) is also credited for this discovery. ''B. anthracis'' was the first bacterium conclusively demonstrated to cause disease, by [[Robert Koch]] in 1876.<ref>Koch, R. (1876) "Untersuchungen über Bakterien: V. Die Ätiologie der Milzbrand-Krankheit, begründet auf die Entwicklungsgeschichte des ''Bacillus anthracis''" (Investigations into bacteria: V. The etiology of anthrax, based on the ontogenesis of ''Bacillus anthracis''), Cohns ''Beitrage zur Biologie der Pflanzen'', vol. 2, no. 2, [http://edoc.rki.de/documents/rk/508-5-26/PDF/5-26.pdf pages 277–310].</ref> The species name ''anthracis'' is from the [[Greek language|Greek]] ''anthrax''<!--[sic]--> (ἄνθραξ), meaning "coal" and referring to the most common form of the disease, [[cutaneous]] anthrax, in which large, black skin [[lesion]]s are formed.


Image: Bacillus_anthracis02.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
==Genome structure==
''B. anthracis'' has a single chromosome which is a circular, 5,227,293-bp DNA molecule.<ref name="Read">{{cite journal|last=Read|first=TD|coauthors=Peterson, SN; Tourasse, N; Baillie, LW; Paulsen, IT; Nelson, KE; Tettelin, H; Fouts, DE; Eisen, JA; Gill, SR; Holtzapple, EK; Okstad, OA; Helgason, E; Rilstone, J; Wu, M; Kolonay, JF; Beanan, MJ; Dodson, RJ; Brinkac, LM; Gwinn, M; DeBoy, RT; Madpu, R; Daugherty, SC; Durkin, AS; Haft, DH; Nelson, WC; Peterson, JD; Pop, M; Khouri, HM; Radune, D; Benton, JL; Mahamoud, Y; Jiang, L; Hance, IR; Weidman, JF; Berry, KJ; Plaut, RD; Wolf, AM; Watkins, KL; Nierman, WC; Hazen, A; Cline, R; Redmond, C; Thwaite, JE; White, O; Salzberg, SL; Thomason, B; Friedlander, AM; Koehler, TM; Hanna, PC; Kolstø, AB; Fraser, CM|title=The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria.|journal=Nature|date=May 1, 2003|volume=423|issue=6935|pages=81–6|pmid=12721629|doi=10.1038/nature01586}}</ref>  It also has two circular, extrachromosomal, double-stranded DNA plasmids, pXO1 and pXO2. Both the pXO1 and pXO2 plasmids are required for full virulence and represent two distinct plasmid families.<ref name="Kolstø">{{cite journal|last=Kolstø|first=Anne-Brit|author2=Tourasse, Nicolas J.|author3= Økstad, Ole Andreas|title=What Sets                            Apart from Other                            Species?|journal=Annual Review of Microbiology|date=1 October 2009|volume=63|issue=1|pages=451–476|doi=10.1146/annurev.micro.091208.073255}}</ref>


Image: Bacillus_anthracis03.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
{| class="wikitable"
|-
! Feature !! scope="col" width="100px" | Chromosome !! scope="col" width="100px" | pXO1 !! scope="col" width="100px" | pXO2
|-
| Size (bp) || align="right"|5,227,293 || align="right"|181,677 || align="right"|94,829
|-
| Number of genes || align="right"|5,508 || align="right"|217 || align="right"|113
|-
| [[Replicon (genetics)|Replicon]] coding (%) || align="right"|84.3 || align="right"|77.1 || align="right"|76.2
|-
| Average [[gene]] length (nt) || align="right"|800 || align="right"|645 || align="right"|639
|-
| G+C content (%) || align="right"|35.4 || align="right"|32.5 || align="right"|33.0
|-
| [[rRNA]] operons || align="right"|11 || align="right"|0 || align="right"|0
|-
| [[tRNA]]s || align="right"|95 || align="right"|0 || align="right"|0
|-
| [[Small RNA|sRNAs]] || align="right"|3 || align="right"|2 || align="right"|0
|-
| [[Phage]] genes || align="right"|62 || align="right"|0 || align="right"|0
|-
| [[Transposon]] genes || align="right"|18 || align="right"|15 || align="right"|6
|-
| Disrupted reading frame || align="right"|37 || align="right"|5 || align="right"|7
|-
| Genes with assigned function || align="right"|2,762 || align="right"|65 || align="right"|38
|-
| Conserved hypothetical genes || align="right"|1,212 || align="right"|22 || align="right"|19
|-
| Genes of unknown function || align="right"|657 || align="right"|8 || align="right"|5
|-
| Hypothetical genes || align="right"|877 || align="right"|122 || align="right"|51
|}


Image: Bacillus_anthracis05.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===pXO1 plasmid===
The pXO1 plasmid (182 kb) contains the genes that encode for the [[anthrax toxin]] components: ''pag'' (protective antigen, PA), ''lef'' (lethal factor, LF), and ''cya'' (edema factor, EF). These factors are contained within a 44.8-kb [[pathogenicity island]] (PAI). The lethal toxin is a combination of PA with LF and the edema toxin is a combination of PA with EF. The PAI also contains genes which encode a [[transcriptional activator]] AtxA and the [[repressor]] PagR, both of which regulate the expression of the anthrax toxin genes.<ref name="Kolstø" />


Image: Bacillus_anthracis06.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===pXO2 plasmid===
pXO2 encodes a five-gene [[operon]] (''capBCADE'') which synthesizes a poly-γ-D-glutamic acid (polyglutamate) capsule.  This capsule allows ''B. anthracis'' to evade the host immune system by protecting itself from [[phagocytosis]]. Expression of the capsule operon is activated by the transcriptional regulators AcpA and AcpB, located in the pXO2 pathogenicity island (35 kb). Interestingly, AcpA and AcpB expression are under the control of AtxA from pXO1.<ref name="Kolstø" />


Image: Bacillus_anthracis07.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
==Strains==
The 89 known strains of ''B. anthracis'' include:
*[[Sterne strain]] (34F2; aka the "Weybridge strain"), used by [[Max Sterne]] in his 1930s vaccines
*[[Vollum strain]], formerly weaponized by the US, UK, and Iraq; isolated from cow in [[Oxfordshire]], UK, in 1935
**Vollum M-36, virulent British research strain; passed through macaques 36 times
**Vollum 1B, weaponized by the US and UK in the 1940s-60s
**Vollum-14578, UK biotesting contaminated [[Gruinard Island]], Scotland, in 1940s
**V770-NP1-R, the avirulent, nonencapsulated strain used in the ''[[BioThrax]]'' vaccine
*Anthrax 836, highly virulent strain weaponized by the USSR; discovered in [[Kirov, Kirov Oblast|Kirov]] in 1953
*[[Ames strain]], isolated from a cow in [[Texas]] in 1981; famously used in [[AMERITHRAX]] letter attacks (2001)
**Ames Ancestor
**Ames Florida
*H9401, isolated from human patient in Korea; used in investigational anthrax vaccines<ref name="Chun" />


Image: Bacillus_anthracis08.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
==Evolution==
Whole genome sequencing has made reconstruction of the ''B. anthracis'' phylogeny extremely accurate. A contributing factor to the reconstruction is ''B. anthracis'' being monomorphic, meaning it has low genetic diversity, including the absence of any measurable lateral DNA transfer since its derivation as a species. The lack of diversity is due to a short evolutionary history that has precluded mutational saturation in [[single nucleotide polymorphisms]].<ref name="Keim">{{cite journal|last=Keim|first=Paul|author2=Gruendike, Jeffrey M.|author3= Klevytska, Alexandra M.|author4= Schupp, James M.|author5= Challacombe, Jean|author6= Okinaka, Richard|title=The genome and variation of Bacillus anthracis|journal=Molecular Aspects of Medicine|date=1 December 2009|volume=30|issue=6|pages=397–405|doi=10.1016/j.mam.2009.08.005|pmid=19729033|pmc=3034159}}</ref>


Image: Bacillus_anthracis09.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
A short evolutionary time does not necessarily mean a short chronological time. When DNA is replicated, mistakes occur which become genetic mutations.  The buildup of these mutations over time leads to the evolution of a species. During the ''B. anthracis'' lifecycle, it spends a significant amount of time in the soil spore reservoir stage, a stage in which DNA replication does not occur. These prolonged periods of dormancy have greatly reduced the evolutionary rate of the organism.<ref name="Keim" />


Image: Bacillus_anthracis10.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Nearest neighbors===
''B. anthracis'' belongs to the ''B. cereus'' group consisting of the strains: ''B. cereus'', ''B. anthracis'', ''B. thuringiensis'', ''[[Bacillus weihenstephanensis|B. weihenstephanensis]]'', ''[[Bacillus mycoides|B. mycoides]]'', and ''B. pseudomycoides''.  The first three strains are pathogenic or opportunistic to insects or mammals, while the last three are not considered pathogenic.  The strains of this group are genetically and phenotypically heterogeneous overall, but some of the strains are more closely related and phylogenetically intermixed at the chromosome level. The ''B. cereus'' group generally exhibits complex genomes and most carry varying numbers of plasmids.<ref name="Kolstø" />


Image: Bacillus_anthracis11.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
''B. cereus'' is a soil-dwelling bacterium which can colonize the gut of invertebrates as a symbiont<ref>{{cite journal|last=Jensen|first=G. B.|author2=Hansen, B. M.|author3= Eilenberg, J.|author4= Mahillon, J.|title=The hidden lifestyles of Bacillus cereus and relatives|journal=Environmental Microbiology|date=18 July 2003|volume=5|issue=8|pages=631–640|doi=10.1046/j.1462-2920.2003.00461.x|pmid=12871230}}</ref>   and is a frequent cause of food poisoning<ref>{{cite journal|last=Drobniewski|first=FA|title=Bacillus cereus and related species.|journal=Clinical Microbiology Reviews|date=October 1993|volume=6|issue=4|pages=324–38|pmid=8269390|pmc=358292}}</ref>  It produces an emetic toxin, enterotoxins, and other virulence factors.<ref>{{cite journal|last=Stenfors Arnesen|first=Lotte P.|author2=Fagerlund, Annette|author3= Granum, Per Einar|title=From soil to gut:                            and its food poisoning toxins|journal=FEMS Microbiology Reviews|date=1 July 2008|volume=32|issue=4|pages=579–606|doi=10.1111/j.1574-6976.2008.00112.x|pmid=18422617}}</ref>   The enterotoxins and virulence factors are encoded on the chromosome, while the emetic toxin is encoded on a 270-kb plasmid, pCER270.<ref name="Kolstø" />


Image: Bacillus_anthracis12.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
''B. thuringiensis'' is an insect pathogen and is characterized by production of parasporal crystals of insecticidal toxins Cry and Cyt.<ref>{{cite journal|last=Schnepf|first=E|author2=Crickmore, N|author3=Van Rie, J|author4=Lereclus, D|author5=Baum, J|author6=Feitelson, J|author7=Zeigler, DR|author8= Dean, DH|title=Bacillus thuringiensis and its pesticidal crystal proteins.|journal=Microbiology and molecular biology reviews : MMBR|date=September 1998|volume=62|issue=3|pages=775–806|pmid=9729609|pmc=98934}}</ref>   The genes encoding these proteins are commonly located on plasmids which can be lost from the organism, making it indistinguishable from ''B. cereus''.<ref name="Kolstø" />


Image: Bacillus_anthracis13.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Pseudogene===
''PlcR'' is a global transcriptional regulator which controls most of the secreted virulence factors in ''B. cereus'' and ''B. thuringiensis''.  It is chromosomally encoded and is ubiquitous throughout the cell.<ref>{{cite journal|last=Agaisse|first=H|author2=Gominet, M|author3= Okstad, OA|author4= Kolstø, AB|author5= Lereclus, D|title=PlcR is a pleiotropic regulator of extracellular virulence factor gene expression in Bacillus thuringiensis.|journal=Molecular microbiology|date=June 1999|volume=32|issue=5|pages=1043–53|pmid=10361306|doi=10.1046/j.1365-2958.1999.01419.x}}</ref>   In ''B. anthracis'', however, the ''plcR'' gene contains a single base change at position 640, a nonsense mutation, which creates a dysfunctional protein. While 1% of the ''B. cereus'' group carries an inactivated ''plcR'' gene, none of them carries the specific mutation found only in ''B. anthracis''.<ref>{{cite journal|last=Slamti|first=L|author2=Perchat, S|author3=Gominet, M|author4=Vilas-Bôas, G|author5=Fouet, A|author6=Mock, M|author7=Sanchis, V|author8=Chaufaux, J|author9=Gohar, M|author10= Lereclus, D|title=Distinct mutations in PlcR explain why some strains of the Bacillus cereus group are nonhemolytic.|journal=Journal of bacteriology|date=June 2004|volume=186|issue=11|pages=3531–8|pmid=15150241|doi=10.1128/JB.186.11.3531-3538.2004|pmc=415780}}</ref>


Image: Bacillus_anthracis14.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
The ''plcR'' gene is part of a two-gene operon with ''papR''.<ref>{{cite journal|last=Okstad|first=OA|author2=Gominet, M|author3= Purnelle, B|author4= Rose, M|author5= Lereclus, D|author6= Kolstø, AB|title=Sequence analysis of three Bacillus cereus loci carrying PIcR-regulated genes encoding degradative enzymes and enterotoxin.|journal=Microbiology (Reading, England)|date=November 1999|volume=145|pages=3129–38|pmid=10589720|issue=11}}</ref><ref name="Slamti">{{cite journal|last=Slamti|first=L|author2=Lereclus, D|title=A cell-cell signaling peptide activates the PlcR virulence regulon in bacteria of the Bacillus cereus group.|journal=The EMBO Journal|date=Sep 2, 2002|volume=21|issue=17|pages=4550–9|pmid=12198157|pmc=126190|doi=10.1093/emboj/cdf450}}</ref>  The ''papR'' gene encodes a small protein which is secreted from the cell and the reimported as a processed heptapeptide forming a quorum-sensing system.<ref name="Slamti" /><ref>{{cite journal|last=Bouillaut|first=L|author2=Perchat, S|author3=Arold, S|author4=Zorrilla, S|author5=Slamti, L|author6=Henry, C|author7=Gohar, M|author8=Declerck, N|author9= Lereclus, D|title=Molecular basis for group-specific activation of the virulence regulator PlcR by PapR heptapeptides|journal=Nucleic Acids Research|date=June 2008|volume=36|issue=11|pages=3791–801|pmid=18492723|doi=10.1093/nar/gkn149|pmc=2441798}}</ref> The lack of PlcR in ''B. anthracis'' is a principle characteristic differentiating it from other members of the ''B. cereus'' group.  While ''B. cereus'' and ''B. thuringiensis'' depend on the ''plcR'' gene for expression of their virulence factors, ''B. anthracis'' relies on the pXO1 and pXO2 plasmids for its virulence.<ref name="Kolstø" />


Image: Bacillus_anthracis15.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
==Clinical aspects==
{{Main|Anthrax}}


Image: Bacillus_anthracis16.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Pathogenesis===
''B. anthracis'' possesses an antiphagocytic capsule essential for full virulence. The organism also
produces three plasmid-coded exotoxins: edema factor, a calmodulin-dependent adenylate cyclase, causes elevation of intracellular cAMP, and is responsible for the severe edema usually seen in ''B. anthracis'' infections; lethal toxin is responsible for tissue necrosis; protective antigen (so named because of its use in producing protective anthrax vaccines) mediates cell entry of edema factor and lethal toxin.


Image: Bacillus_anthracis17.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Manifestations in human disease===
Three forms of human anthrax disease are recognized based on their [[portal of entry]].
*Cutaneous, the most common form (95%), causes a localized, inflammatory, black, necrotic lesion ([[eschar]]).
*Pulmonary, the highly fatal form, is characterized by sudden, massive chest [[edema]] followed by cardiovascular shock.
*Gastrointestinal, a rare but also fatal (causes death to 25%) type, results from ingestion of spores.


Image: Bacillus_anthracis18.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Prevention and treatment===
A number of [[anthrax vaccines]] have been developed for preventive use in livestock and humans. Anthrax Vaccine Adsorbed (AVA) may protect against cutaneous and inhalation anthrax. However, this vaccine is only used for at-risk adults before exposure to anthrax and has not been approved for use after exposure.<ref>http://www.cdc.gov/anthrax/medicalcare/prevention/antibiotics.html</ref> Infections with ''B. anthracis'' can be treated with [[Beta-lactam|β-lactam]] [[antibiotic]]s such as [[penicillin]], and others which are active against Gram-positive bacteria.<ref>{{cite journal |author = Barnes JM |title=Penicillin and ''B. anthracis'' |journal= J Path Bacteriol |volume=194|year=1947|pages=113–125 |doi=10.1002/path.1700590113}}</ref> Penicillin-resistant ''B. anthracis'' can be treated with [[fluoroquinolones]] such as [[ciprofloxacin]] or tetracycline antibiotics such as [[doxycycline]].


Image: Bacillus_anthracis19.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
== Laboratory research ==
Components of [[tea]], such as [[polyphenols in tea|polyphenol]]s, have the ability to inhibit the activity both of ''B. anthracis'' and its toxin considerably; spores, however, are not affected. The addition of milk to the tea completely inhibits its antibacterial activity against anthrax.<ref>{{cite web|url = http://web.archive.org/web/20090213231226/http://www.sfam.org.uk/newsarticle.php?214&2 |title=Anthrax and tea|publisher = Society for Applied Microbiology |accessdate = 2011-12-21|date=2011-12-21}}</ref> Activity against the ''B. athracis'' in the [[laboratory]] does not prove that drinking tea affects the course of an infection, since it is unknown how these polyphenols are absorbed and distributed within the body.


Image: Bacillus_anthracis20.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
===Recent research===
Advances in genotyping methods have led to improved genetic analysis for variation and relatedness. These methods include multiple-locus variable-number tandem repeat analysis ([[MLVA]]) and typing systems using canonical [[single-nucleotide polymorphisms]]. The Ames ancestor chromosome was sequenced in 2003<ref name="Read" /> and contributes to the identification of genes involved in the virulence of ''B. anthracis''. Recently, ''B. anthracis'' isolate H9401 was isolated from a Korean patient suffering from gastrointestinal anthrax.  The goal of the Republic of Korea is to use this strain as a challenge strain to develop a recombinant vaccine against anthrax.<ref name="Chun">{{cite journal|last=Chun|first=J.-H.|author2=Hong, K.-J.|author3=Cha, S. H.|author4=Cho, M.-H.|author5=Lee, K. J.|author6=Jeong, D. H.|author7=Yoo, C.-K.|author8= Rhie, G.-e.|title=Complete Genome Sequence of Bacillus anthracis H9401, an Isolate from a Korean Patient with Anthrax|journal=Journal of Bacteriology|date=18 July 2012|volume=194|issue=15|pages=4116–4117|doi=10.1128/JB.00159-12|pmid=22815438|pmc=3416559}}</ref>


Image: Bacillus_anthracis21.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
The H9401 strain isolated in the Republic of Korea was sequenced using [[454 Life Sciences|454]] GS-FLX technology and analyzed using several bioinformatics tools to align, annotate, and compare H9401 to other ''B. anthracis'' strains.  The sequencing coverage level suggests a molecular ratio of pXO1:pXO2:chromosome as 3:2:1 which is identical to the Ames Florida and Ames Ancestor strains. H9401 has 99.679% sequence homology with Ames Ancestor with an [[amino acid]] sequence homology of 99.870%. H9401 has a circular chromosome (5,218,947 bp with 5,480 predicted [[Open reading frame|ORF]]s), the pXO1 plasmid (181,700 bp with 202 predicted ORFs), and the pXO2 plasmid (94,824 bp with 110 predicted ORFs).<ref name="Chun" /> As compared to the Ames Ancestor chromosome above, the H9401 chromosome is about 8.5 kb smaller. Due to the high pathogenecity and sequence similarity to the Ames Ancestor, H9401 will be used as a reference for testing the efficacy of candidate anthrax vaccines by the Repbulic of Korea.<ref name="Chun" />


Image: Bacillus_anthracis22.jpeg| Bacillus anthracis. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
== Host interactions ==
As with most other pathogenic bacteria, ''B. anthracis'' must acquire iron to grow and proliferate in its host environment. The most readily available iron sources for pathogenic bacteria are the [[heme]] groups used by the host in the transport of oxygen. To scavenge heme from host [[hemoglobin]] and [[myoglobin]], ''B. anthracis'' uses two secretory [[siderophore]] proteins, IsdX1 and IsdX2. These proteins can separate heme from hemoglobin, allowing surface proteins of ''B. anthracis'' to transport it into the cell.<ref>{{cite journal |author = Maresso AW, Garufi G, Schneewind O |title=Bacillus anthracis Secretes Proteins That Mediate Heme Acquisition from Hemoglobin |journal= PLOS Pathogens |volume=4(8): e1000132|year=2008}}</ref>


</gallery>
== References ==
{{Reflist|2}}


==References==
== External links ==
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See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for a
* [http://patricbrc.org/portal/portal/patric/Taxon?cType=taxon&cId=1392 Bacillus anthracis] genomes and related information at [http://patricbrc.org/ PATRIC], a Bioinformatics Resource Center funded by [http://www.niaid.nih.gov/ NIAID]
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Revision as of 15:28, 5 August 2015

style="background:#Template:Taxobox colour;"|Bacillus anthracis
Photomicrograph of Bacillus anthracis (fuchsin-methylene blue spore stain)
Photomicrograph of Bacillus anthracis (fuchsin-methylene blue spore stain)
style="background:#Template:Taxobox colour;" | Scientific classification
Domain: Bacteria
Phylum: Firmicutes
Class: Bacilli
Order: Bacillales
Family: Bacillaceae
Genus: Bacillus
Species: B. anthracis
Binomial name
Bacillus anthracis
Cohn 1872

Bacillus anthracis is the etiologic agent of anthrax—a common disease of livestock and, occasionally, of humans—and the only obligate pathogen within the genus Bacillus.[1] B. anthracis is a Gram-positive, endospore-forming, rod-shaped bacterium, with a width of 1.0–1.2 µm and a length of 3–5 µm.[1] It can be grown in an ordinary nutrient medium under aerobic or anaerobic conditions.[2]

File:Bacillus anthracis belongs to the Bacillus cereus group of strains.png
B. anthracis belongs to the B. cereus group of strains.
File:B anthracis diagram en.png
Structure of B. anthracis

It is one of few bacteria known to synthesize a protein capsule (poly-D-gamma-glutamic acid). Like Bordetella pertussis, it forms a calmodulin-dependent adenylate cyclase exotoxin known as (edema factor), along with lethal factor. It bears close genotypical and phenotypical resemblance to Bacillus cereus and Bacillus thuringiensis. All three species share cellular dimensions and morphology. All form oval spores located centrally in an unswollen sporangium. B. anthracis spores, in particular, are highly resilient, surviving extremes of temperature, low-nutrient environments, and harsh chemical treatment over decades or centuries.

The spore is a dehydrated cell with thick walls and additional layers that form inside the cell membrane. It can remain inactive for many years, but if it comes into a favorable environment, it begins to grow again. It is sometimes called an endospore because it initially develops inside the rod-shaped form. Features such as the location within the rod, the size and shape of the endospore, and whether or not it causes the wall of the rod to bulge out are characteristic of particular species of Bacillus. Depending upon the species, the endospores are round, oval, or occasionally cylindrical. They are highly refractile and contain dipicolinic acid. Electron micrograph sections show they have a thin outer spore coat, a thick spore cortex, and an inner spore membrane surrounding the spore contents. The spores resist heat, drying, and many disinfectants (including 95% ethanol).[3] Because of these attributes, B. anthracis spores are extraordinarily well-suited to use (in powdered and aerosol form) as biological weapons. Such weaponization has been accomplished in the past by at least five state bioweapons programs—those of the United Kingdom, Japan, the United States, Russia, and Iraq—and has been attempted by several others.[4]

Historical background

File:Bacillus anthracis - CapD protein crystal structure.jpg
CapD protein crystal structure of B. anthracis

French physician Casimir Davaine (1812-1882) demonstrated the symptoms of anthrax were invariably accompanied by the microbe B. anthracis.[5] German physician Aloys Pollender (1799–1879) is also credited for this discovery. B. anthracis was the first bacterium conclusively demonstrated to cause disease, by Robert Koch in 1876.[6] The species name anthracis is from the Greek anthrax (ἄνθραξ), meaning "coal" and referring to the most common form of the disease, cutaneous anthrax, in which large, black skin lesions are formed.

Genome structure

B. anthracis has a single chromosome which is a circular, 5,227,293-bp DNA molecule.[7] It also has two circular, extrachromosomal, double-stranded DNA plasmids, pXO1 and pXO2. Both the pXO1 and pXO2 plasmids are required for full virulence and represent two distinct plasmid families.[8]

Feature Chromosome pXO1 pXO2
Size (bp) 5,227,293 181,677 94,829
Number of genes 5,508 217 113
Replicon coding (%) 84.3 77.1 76.2
Average gene length (nt) 800 645 639
G+C content (%) 35.4 32.5 33.0
rRNA operons 11 0 0
tRNAs 95 0 0
sRNAs 3 2 0
Phage genes 62 0 0
Transposon genes 18 15 6
Disrupted reading frame 37 5 7
Genes with assigned function 2,762 65 38
Conserved hypothetical genes 1,212 22 19
Genes of unknown function 657 8 5
Hypothetical genes 877 122 51

pXO1 plasmid

The pXO1 plasmid (182 kb) contains the genes that encode for the anthrax toxin components: pag (protective antigen, PA), lef (lethal factor, LF), and cya (edema factor, EF). These factors are contained within a 44.8-kb pathogenicity island (PAI). The lethal toxin is a combination of PA with LF and the edema toxin is a combination of PA with EF. The PAI also contains genes which encode a transcriptional activator AtxA and the repressor PagR, both of which regulate the expression of the anthrax toxin genes.[8]

pXO2 plasmid

pXO2 encodes a five-gene operon (capBCADE) which synthesizes a poly-γ-D-glutamic acid (polyglutamate) capsule. This capsule allows B. anthracis to evade the host immune system by protecting itself from phagocytosis. Expression of the capsule operon is activated by the transcriptional regulators AcpA and AcpB, located in the pXO2 pathogenicity island (35 kb). Interestingly, AcpA and AcpB expression are under the control of AtxA from pXO1.[8]

Strains

The 89 known strains of B. anthracis include:

  • Sterne strain (34F2; aka the "Weybridge strain"), used by Max Sterne in his 1930s vaccines
  • Vollum strain, formerly weaponized by the US, UK, and Iraq; isolated from cow in Oxfordshire, UK, in 1935
    • Vollum M-36, virulent British research strain; passed through macaques 36 times
    • Vollum 1B, weaponized by the US and UK in the 1940s-60s
    • Vollum-14578, UK biotesting contaminated Gruinard Island, Scotland, in 1940s
    • V770-NP1-R, the avirulent, nonencapsulated strain used in the BioThrax vaccine
  • Anthrax 836, highly virulent strain weaponized by the USSR; discovered in Kirov in 1953
  • Ames strain, isolated from a cow in Texas in 1981; famously used in AMERITHRAX letter attacks (2001)
    • Ames Ancestor
    • Ames Florida
  • H9401, isolated from human patient in Korea; used in investigational anthrax vaccines[9]

Evolution

Whole genome sequencing has made reconstruction of the B. anthracis phylogeny extremely accurate. A contributing factor to the reconstruction is B. anthracis being monomorphic, meaning it has low genetic diversity, including the absence of any measurable lateral DNA transfer since its derivation as a species. The lack of diversity is due to a short evolutionary history that has precluded mutational saturation in single nucleotide polymorphisms.[10]

A short evolutionary time does not necessarily mean a short chronological time. When DNA is replicated, mistakes occur which become genetic mutations. The buildup of these mutations over time leads to the evolution of a species. During the B. anthracis lifecycle, it spends a significant amount of time in the soil spore reservoir stage, a stage in which DNA replication does not occur. These prolonged periods of dormancy have greatly reduced the evolutionary rate of the organism.[10]

Nearest neighbors

B. anthracis belongs to the B. cereus group consisting of the strains: B. cereus, B. anthracis, B. thuringiensis, B. weihenstephanensis, B. mycoides, and B. pseudomycoides. The first three strains are pathogenic or opportunistic to insects or mammals, while the last three are not considered pathogenic. The strains of this group are genetically and phenotypically heterogeneous overall, but some of the strains are more closely related and phylogenetically intermixed at the chromosome level. The B. cereus group generally exhibits complex genomes and most carry varying numbers of plasmids.[8]

B. cereus is a soil-dwelling bacterium which can colonize the gut of invertebrates as a symbiont[11] and is a frequent cause of food poisoning[12] It produces an emetic toxin, enterotoxins, and other virulence factors.[13] The enterotoxins and virulence factors are encoded on the chromosome, while the emetic toxin is encoded on a 270-kb plasmid, pCER270.[8]

B. thuringiensis is an insect pathogen and is characterized by production of parasporal crystals of insecticidal toxins Cry and Cyt.[14] The genes encoding these proteins are commonly located on plasmids which can be lost from the organism, making it indistinguishable from B. cereus.[8]

Pseudogene

PlcR is a global transcriptional regulator which controls most of the secreted virulence factors in B. cereus and B. thuringiensis. It is chromosomally encoded and is ubiquitous throughout the cell.[15] In B. anthracis, however, the plcR gene contains a single base change at position 640, a nonsense mutation, which creates a dysfunctional protein. While 1% of the B. cereus group carries an inactivated plcR gene, none of them carries the specific mutation found only in B. anthracis.[16]

The plcR gene is part of a two-gene operon with papR.[17][18] The papR gene encodes a small protein which is secreted from the cell and the reimported as a processed heptapeptide forming a quorum-sensing system.[18][19] The lack of PlcR in B. anthracis is a principle characteristic differentiating it from other members of the B. cereus group. While B. cereus and B. thuringiensis depend on the plcR gene for expression of their virulence factors, B. anthracis relies on the pXO1 and pXO2 plasmids for its virulence.[8]

Clinical aspects

Main article: Anthrax

Pathogenesis

B. anthracis possesses an antiphagocytic capsule essential for full virulence. The organism also produces three plasmid-coded exotoxins: edema factor, a calmodulin-dependent adenylate cyclase, causes elevation of intracellular cAMP, and is responsible for the severe edema usually seen in B. anthracis infections; lethal toxin is responsible for tissue necrosis; protective antigen (so named because of its use in producing protective anthrax vaccines) mediates cell entry of edema factor and lethal toxin.

Manifestations in human disease

Three forms of human anthrax disease are recognized based on their portal of entry.

  • Cutaneous, the most common form (95%), causes a localized, inflammatory, black, necrotic lesion (eschar).
  • Pulmonary, the highly fatal form, is characterized by sudden, massive chest edema followed by cardiovascular shock.
  • Gastrointestinal, a rare but also fatal (causes death to 25%) type, results from ingestion of spores.

Prevention and treatment

A number of anthrax vaccines have been developed for preventive use in livestock and humans. Anthrax Vaccine Adsorbed (AVA) may protect against cutaneous and inhalation anthrax. However, this vaccine is only used for at-risk adults before exposure to anthrax and has not been approved for use after exposure.[20] Infections with B. anthracis can be treated with β-lactam antibiotics such as penicillin, and others which are active against Gram-positive bacteria.[21] Penicillin-resistant B. anthracis can be treated with fluoroquinolones such as ciprofloxacin or tetracycline antibiotics such as doxycycline.

Laboratory research

Components of tea, such as polyphenols, have the ability to inhibit the activity both of B. anthracis and its toxin considerably; spores, however, are not affected. The addition of milk to the tea completely inhibits its antibacterial activity against anthrax.[22] Activity against the B. athracis in the laboratory does not prove that drinking tea affects the course of an infection, since it is unknown how these polyphenols are absorbed and distributed within the body.

Recent research

Advances in genotyping methods have led to improved genetic analysis for variation and relatedness. These methods include multiple-locus variable-number tandem repeat analysis (MLVA) and typing systems using canonical single-nucleotide polymorphisms. The Ames ancestor chromosome was sequenced in 2003[7] and contributes to the identification of genes involved in the virulence of B. anthracis. Recently, B. anthracis isolate H9401 was isolated from a Korean patient suffering from gastrointestinal anthrax. The goal of the Republic of Korea is to use this strain as a challenge strain to develop a recombinant vaccine against anthrax.[9]

The H9401 strain isolated in the Republic of Korea was sequenced using 454 GS-FLX technology and analyzed using several bioinformatics tools to align, annotate, and compare H9401 to other B. anthracis strains. The sequencing coverage level suggests a molecular ratio of pXO1:pXO2:chromosome as 3:2:1 which is identical to the Ames Florida and Ames Ancestor strains. H9401 has 99.679% sequence homology with Ames Ancestor with an amino acid sequence homology of 99.870%. H9401 has a circular chromosome (5,218,947 bp with 5,480 predicted ORFs), the pXO1 plasmid (181,700 bp with 202 predicted ORFs), and the pXO2 plasmid (94,824 bp with 110 predicted ORFs).[9] As compared to the Ames Ancestor chromosome above, the H9401 chromosome is about 8.5 kb smaller. Due to the high pathogenecity and sequence similarity to the Ames Ancestor, H9401 will be used as a reference for testing the efficacy of candidate anthrax vaccines by the Repbulic of Korea.[9]

Host interactions

As with most other pathogenic bacteria, B. anthracis must acquire iron to grow and proliferate in its host environment. The most readily available iron sources for pathogenic bacteria are the heme groups used by the host in the transport of oxygen. To scavenge heme from host hemoglobin and myoglobin, B. anthracis uses two secretory siderophore proteins, IsdX1 and IsdX2. These proteins can separate heme from hemoglobin, allowing surface proteins of B. anthracis to transport it into the cell.[23]

References

  1. ↑ 1.0 1.1 Spencer, RC (March 2003). "Bacillus anthracis". Journal of clinical pathology. 56 (3): 182–7. doi:10.1136/jcp.56.3.182. PMC 1769905. PMID 12610093.
  2. ↑ Holt, J. G., N. R. Krieg, P. H. A. Sneath, J. T. Staley, and S. T. Williams. 1994. Group 17: gram-positive cocci, p. 527–558. In W. R. Hensyl (ed.), Bergey's manual of determinative bacteriology, 9th ed. Williams and Wilkins, Baltimore, Md.
  3. ↑ Bergey's Manual of Systematic Bacteriology, vol. 2, p. 1105, 1986, Sneath, P.H.A.; Mair, N.S.; Sharpe, M.E.; Holt, J.G. (eds.); Williams & Wilkins, Baltimore, Maryland, USA
  4. ↑ Zilinskas, Raymond A. (1999), "Iraq's Biological Warfare Program: The Past as Future?", Chapter 8 in: Lederberg, Joshua (editor), Biological Weapons: Limiting the Threat (1999), The MIT Press, pp 137-158.
  5. ↑ Théodoridès, J (April 1966). "Casimir Davaine (1812-1882): a precursor of Pasteur". Medical history. 10 (2): 155–65. doi:10.1017/S0025727300010942. PMC 1033586. PMID 5325873.
  6. ↑ Koch, R. (1876) "Untersuchungen über Bakterien: V. Die Ätiologie der Milzbrand-Krankheit, begründet auf die Entwicklungsgeschichte des Bacillus anthracis" (Investigations into bacteria: V. The etiology of anthrax, based on the ontogenesis of Bacillus anthracis), Cohns Beitrage zur Biologie der Pflanzen, vol. 2, no. 2, pages 277–310.
  7. ↑ 7.0 7.1 Read, TD (May 1, 2003). "The genome sequence of Bacillus anthracis Ames and comparison to closely related bacteria". Nature. 423 (6935): 81–6. doi:10.1038/nature01586. PMID 12721629. Unknown parameter |coauthors= ignored (help)
  8. ↑ 8.0 8.1 8.2 8.3 8.4 8.5 8.6 Kolstø, Anne-Brit; Tourasse, Nicolas J.; Økstad, Ole Andreas (1 October 2009). "What Sets Apart from Other Species?". Annual Review of Microbiology. 63 (1): 451–476. doi:10.1146/annurev.micro.091208.073255.
  9. ↑ 9.0 9.1 9.2 9.3 Chun, J.-H.; Hong, K.-J.; Cha, S. H.; Cho, M.-H.; Lee, K. J.; Jeong, D. H.; Yoo, C.-K.; Rhie, G.-e. (18 July 2012). "Complete Genome Sequence of Bacillus anthracis H9401, an Isolate from a Korean Patient with Anthrax". Journal of Bacteriology. 194 (15): 4116–4117. doi:10.1128/JB.00159-12. PMC 3416559. PMID 22815438.
  10. ↑ 10.0 10.1 Keim, Paul; Gruendike, Jeffrey M.; Klevytska, Alexandra M.; Schupp, James M.; Challacombe, Jean; Okinaka, Richard (1 December 2009). "The genome and variation of Bacillus anthracis". Molecular Aspects of Medicine. 30 (6): 397–405. doi:10.1016/j.mam.2009.08.005. PMC 3034159. PMID 19729033.
  11. ↑ Jensen, G. B.; Hansen, B. M.; Eilenberg, J.; Mahillon, J. (18 July 2003). "The hidden lifestyles of Bacillus cereus and relatives". Environmental Microbiology. 5 (8): 631–640. doi:10.1046/j.1462-2920.2003.00461.x. PMID 12871230.
  12. ↑ Drobniewski, FA (October 1993). "Bacillus cereus and related species". Clinical Microbiology Reviews. 6 (4): 324–38. PMC 358292. PMID 8269390.
  13. ↑ Stenfors Arnesen, Lotte P.; Fagerlund, Annette; Granum, Per Einar (1 July 2008). "From soil to gut: and its food poisoning toxins". FEMS Microbiology Reviews. 32 (4): 579–606. doi:10.1111/j.1574-6976.2008.00112.x. PMID 18422617.
  14. ↑ Schnepf, E; Crickmore, N; Van Rie, J; Lereclus, D; Baum, J; Feitelson, J; Zeigler, DR; Dean, DH (September 1998). "Bacillus thuringiensis and its pesticidal crystal proteins". Microbiology and molecular biology reviews : MMBR. 62 (3): 775–806. PMC 98934. PMID 9729609.
  15. ↑ Agaisse, H; Gominet, M; Okstad, OA; Kolstø, AB; Lereclus, D (June 1999). "PlcR is a pleiotropic regulator of extracellular virulence factor gene expression in Bacillus thuringiensis". Molecular microbiology. 32 (5): 1043–53. doi:10.1046/j.1365-2958.1999.01419.x. PMID 10361306.
  16. ↑ Slamti, L; Perchat, S; Gominet, M; Vilas-Bôas, G; Fouet, A; Mock, M; Sanchis, V; Chaufaux, J; Gohar, M; Lereclus, D (June 2004). "Distinct mutations in PlcR explain why some strains of the Bacillus cereus group are nonhemolytic". Journal of bacteriology. 186 (11): 3531–8. doi:10.1128/JB.186.11.3531-3538.2004. PMC 415780. PMID 15150241.
  17. ↑ Okstad, OA; Gominet, M; Purnelle, B; Rose, M; Lereclus, D; Kolstø, AB (November 1999). "Sequence analysis of three Bacillus cereus loci carrying PIcR-regulated genes encoding degradative enzymes and enterotoxin". Microbiology (Reading, England). 145 (11): 3129–38. PMID 10589720.
  18. ↑ 18.0 18.1 Slamti, L; Lereclus, D (Sep 2, 2002). "A cell-cell signaling peptide activates the PlcR virulence regulon in bacteria of the Bacillus cereus group". The EMBO Journal. 21 (17): 4550–9. doi:10.1093/emboj/cdf450. PMC 126190. PMID 12198157.
  19. ↑ Bouillaut, L; Perchat, S; Arold, S; Zorrilla, S; Slamti, L; Henry, C; Gohar, M; Declerck, N; Lereclus, D (June 2008). "Molecular basis for group-specific activation of the virulence regulator PlcR by PapR heptapeptides". Nucleic Acids Research. 36 (11): 3791–801. doi:10.1093/nar/gkn149. PMC 2441798. PMID 18492723.
  20. ↑ http://www.cdc.gov/anthrax/medicalcare/prevention/antibiotics.html
  21. ↑ Barnes JM (1947). "Penicillin and B. anthracis". J Path Bacteriol. 194: 113–125. doi:10.1002/path.1700590113.
  22. ↑ "Anthrax and tea". Society for Applied Microbiology. 2011-12-21. Retrieved 2011-12-21.
  23. ↑ Maresso AW, Garufi G, Schneewind O (2008). "Bacillus anthracis Secretes Proteins That Mediate Heme Acquisition from Hemoglobin". PLOS Pathogens. 4(8): e1000132.

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