View source for Bacillus anthracis

{{Taxobox
| name = ''Bacillus anthracis''
| image = Bacillus_anthracis.png
| image_width = 240px
| image_caption = Photomicrograph of ''Bacillus anthracis'' (fuchsin-methylene blue spore stain)
| domain = [[Bacterium|Bacteria]]
| kingdom = [[Archaebacteria]]
| phylum = [[Firmicutes]]
| classis = [[Bacilli]]
| ordo = [[Bacillales]]
| familia = [[Bacillaceae]]
| genus = ''[[Bacillus]]''
| species = '''''B. anthracis'''''
| binomial = ''Bacillus anthracis''
| binomial_authority = Cohn 1872
}}
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{{About0|Anthrax}}
{{Anthrax}}
{{CMG}}
==Overview==
The causative agent of [[anthrax]] is [[B. anthracis]], a [[motility|nonmotile]], [[Gram-positive]], [[aerobic]] or facultatively [[anaerobic]], [[endospore]]-forming, [[rod]]-shaped [[bacterium]]. The [[spores]] of [[B. anthracis]], which can remain dormant in the environment for decades, are the [[infectious]] form, but this vegetative [[B. anthracis]] rarely causes disease.<ref>{{Cite journal | author = [[Sean V. Shadomy]] & [[Theresa L. Smith]] | title = Zoonosis update. Anthrax | journal = [[Journal of the American Veterinary Medical Association]] | volume = 233 | issue = 1 | pages = 63–72 | year = 2008 | month = July | doi = 10.2460/javma.233.1.63 | pmid = 18593313}}</ref> The [[Bacillus]] may enter the body through the [[skin]], [[lungs]], [[gastrointestinal system]] or by injection, after which they will travel to the [[lymph nodes]]. The [[virulence factor]]s will facilitate the translocation of the [[toxins]] to the [[cytosol]]. The [[natural reservoir]]s of [[Bacillus anthracis]] include humans, mammals, herbivores, reptiles, and birds.

== Historical background ==
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.

==Biology==
[[B. anthracis]], the causative agent of [[anthrax]], is a [[motility|nonmotile]], [[Gram-positive]], [[aerobic]] or facultatively [[anaerobic]], [[endospore]]-forming, [[rod]]-shaped [[bacterium]] approximately 4 μm by 1 μm, although under the microscope it frequently appears in chains of [[cells]]. Like other [[Bacillus]], [[Bacillus anthracis]] is  saprophyte, being able to live in vegetation, air, water and soil.<ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>

These [[bacterial]] [[cells]] may occur isolated, form groups of 2 or more [[cells]] in the body, or long chains in [[cell culture|cultures]].<ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref> In [[blood smear]]s, smears of [[tissue]]s or lesion fluid from [[diagnostic]] specimens, these chains are two to a few [[cells]] in length. In smears made from [[in vitro]] cultures, they can appear as endless strings of [[cells]] - responsible for the characteristic tackiness of the colonies and for the flocculating nature of broth cultures. [[Cell culture]]s appear with a large, grey and curled structure, resembling a "medusa head".<ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>

[[B. anthracis]] have a characteristic square-ended appearance, traditionally associated with its vegetative state, although this may not always be very clear. In the presence of [[oxygen]], ideally at 32 - 35 ºC, and towards the end of the exponential phase of growth, one ellipsoidal [[spore]] (approximately 2 μm by 1 μm in size) is formed within each [[cell]].<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref><ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref> Commonly the [[spores]] will be produced once the [[cell]] senses scarcity of [[nutrients]].<ref name="pmid12610093">{{cite journal| author=Spencer RC| title=Bacillus anthracis. | journal=J Clin Pathol | year= 2003 | volume= 56 | issue= 3 | pages= 182-7 | pmid=12610093 | doi= | pmc=PMC1769905 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=12610093  }} </ref>

The [[spores]] of [[B. anthracis]], which can remain dormant in the environment for decades, being resistant to heat and disinfectants, are the [[infectious]] form, but vegetative [[B. anthracis]] rarely causes disease.<ref>{{Cite journal | author = [[Sean V. Shadomy]] & [[Theresa L. Smith]] | title = Zoonosis update. Anthrax | journal = [[Journal of the American Veterinary Medical Association]] | volume = 233 | issue = 1 | pages = 63–72 | year = 2008 | month = July | doi = 10.2460/javma.233.1.63 | pmid = 18593313}}</ref><ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref>

In the absence of [[oxygen]] and under a high partial pressure of Co2, in the presence of [[bicarbonate]], the vegetative [[cell]] secretes its [[polypeptide]] [[capsule]]. This is one of the two established [[in vivo]] [[virulence factor]]s of [[B. anthracis]]. The [[capsule]] is also a primary [[diagnostic]] aid.<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref> Protective [[antigen]] (PA) and [[edema]] factor (EF) combine to form [[edema]] toxin (ET) and PA and lethal factor (LF) combine to form lethal toxin (LT), the active [[toxins]].<ref>{{Cite journal | author = [[Mahtab Moayeri]] & [[Stephen H. Leppla]] | title = The roles of anthrax toxin in pathogenesis | journal = [[Current opinion in microbiology]] | volume = 7 | issue = 1 | pages = 19–24 | year = 2004 | month = February | doi = 10.1016/j.mib.2003.12.001 | pmid = 15036135}}</ref><ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref>


{| style="float: right;"
| [[File:AnthraxCauses2.png|200px|thumb|none| Photomicrograph depicting a number of Gram-positive, endospore-forming Bacillus anthracis bacteria<SMALL>Courtesy: ''[http://phil.cdc.gov/phil/home.asp Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)]''<ref>{{Cite web | title = http://phil.cdc.gov/phil/details.asp | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL>]]
|-
| [[File:AnthraxCauses1.jpg|200px|thumb|none| Scanning electron micrograph (SEM) depicted spores from the Sterne strain of Bacillus anthracis bacteria<SMALL>Courtesy: ''[http://phil.cdc.gov/phil/home.asp Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)]''<ref>{{Cite web | title = http://phil.cdc.gov/phil/details.asp | url = http://phil.cdc.gov/phil/details.asp}}</ref></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>

{| 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
|}

===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" />

===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" />

==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" />

==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>

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" />

===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" />

''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" />

''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" />

===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>

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" />

== 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.

===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>

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" />

== 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>

==Origin==
[[Bacillus anthracis]] is thought to have originated in Egypt and Mesopotamia. Many scholars think that in Moses’ time, during the 10 plagues of Egypt, [[anthrax]] may have caused what was known as the fifth [[plague]], described as a sickness affecting horses, cattle, sheep, camels and oxen.

==Tropism==
After entering the body (through the [[skin]], [[lungs]], [[gastrointestinal tract]] or by [[injection]]), [[B. anthracis]] [[spores]] are believed to germinate locally or be transported by [[phagocytic cells]] to the [[lymphatics]] and regional [[lymph nodes]], where they germinate.<ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref><ref name="Ross1957">{{cite journal|last1=Ross|first1=Joan M.|title=The pathogenesis of anthrax following the administration of spores by the respiratory route|journal=The Journal of Pathology and Bacteriology|volume=73|issue=2|year=1957|pages=485–494|issn=0368-3494|doi=10.1002/path.1700730219}}</ref> After binding to [[cell]] surface receptors, the PA portion of the complexes facilitates translocation of the [[toxins]] to the [[cytosol]].<ref name="Moayeri2004">{{cite journal|last1=Moayeri|first1=M|title=The roles of anthrax toxin in pathogenesis|journal=Current Opinion in Microbiology|volume=7|issue=1|year=2004|pages=19–24|issn=13695274|doi=10.1016/j.mib.2003.12.001}}</ref><ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref>

==Natural Reservoir==
[[Natural reservoir]]s of [[Bacillus anthracis]] include:<ref name=WHO>{{cite web | title = Anthrax in Humans and Animals | url = http://www.who.int/csr/resources/publications/anthrax_web.pdf }}</ref><ref name="BhatnagarBatra2001">{{cite journal|last1=Bhatnagar|first1=Rakesh|last2=Batra|first2=Smriti|title=Anthrax Toxin|journal=Critical Reviews in Microbiology|volume=27|issue=3|year=2001|pages=167–200|issn=1040-841X|doi=10.1080/20014091096738}}</ref><ref name=CDC>{{cite web | title = Centers for Disease Control and Prevention Expert Panel Meetings on Prevention and Treatment of Anthrax in Adults | url = http://wwwnc.cdc.gov/eid/article/20/2/13-0687_article }}</ref>
* Humans
* Mammals 
* Herbivores
* Reptiles
* Birds

 

== References ==
{{Reflist|2}}

== External links ==
{{commons category|Bacillus anthracis}}
* [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]
* [http://hazard.hegroup.org/query/query_detail.php?c_hazard_ID=64 Hazards in Animal Research Database - ''Bacillus anthracis'']
* [http://pathema.jcvi.org/cgi-bin/Bacillus/PathemaHomePage.cgi Pathema-''Bacillus'' Resource]

{{Gram-positive bacterial diseases}}

[[Category:Anthrax]]
[[Category:Bacillus|anthracis]]
[[Category:Bacteria with sequenced genomes]]