Editing Corynebacterium diphtheriae (section)

==Toxin==
''C. diphtheriae'' produces the diphtheria toxin which alters protein function in the host by inactivating the [[elongation factor]] EF-2. This causes pharyngitis and 'pseudomembrane' in the throat. The strains that are toxigenic are ones which have been infected with a [[bacteriophage]].<ref>{{cite journal | vauthors = Freeman VJ | title = Studies on the virulence of bacteriophage-infected strains of Corynebacterium diphtheriae | journal = Journal of Bacteriology | volume = 61 | issue = 6 | pages = 675–688 | date = June 1951 | pmid = 14850426 | pmc = 386063 | doi = 10.1128/JB.61.6.675-688.1951 }}</ref><ref>{{cite journal |vauthors=Freeman VJ, Morse IU |date=March 1952 |title=Further observations on the change to virulence of bacteriophage-infected a virulent strains of Corynebacterium diphtheria |journal=Journal of Bacteriology |volume=63 |issue=3 |pages=407–414 |doi=10.1128/JB.63.3.407-414.1952 |pmc=169283 |pmid=14927573}}</ref>

The [[diphtheria toxin]] gene is encoded by the bacteriophage found in toxigenic strains, integrated into the bacterial chromosome.<ref name="pmid19007916">{{cite journal | vauthors = Mokrousov I | title = Corynebacterium diphtheriae: genome diversity, population structure and genotyping perspectives | journal = Infection, Genetics and Evolution | volume = 9 | issue = 1 | pages = 1–15 | date = January 2009 | pmid = 19007916 | doi = 10.1016/j.meegid.2008.09.011 | bibcode = 2009InfGE...9....1M }}</ref>

The diphtheria toxin repressor is mainly controlled by iron. It serves as the essential cofactor for the activation of target DNA binding. A
low concentration of iron is required in the medium for toxin production. At high iron concentrations, iron molecules bind to an [[aporepressor]] on the beta bacteriophage, which carries the ''Tox'' gene. When bound to iron, the aporepressor shuts down toxin production.<ref>{{cite book | vauthors = Nester EW, Anderson DG, Roberts CE, Pearsall NN, Nester MT |title=Microbiology: A Human Perspective |date=2004 |publisher=McGraw-Hill Education |location=Boston |isbn=978-0-07-291924-0 |edition=Fourth}}</ref> [[Elek's test]] for toxigenicity is used to determine whether the organism is able to produce the diphtheria toxin.<ref name="pmid7899317">{{cite journal | vauthors = Breton D | title = [Non-toxic Corynebacterium diphtheriae septicemia with endocarditis in an earlier healthy adult. First case and review of the literature] | language = French | journal = Presse Médicale | volume = 23 | issue = 40 | pages = 1859–1861 | date = December 1994 | pmid = 7899317 | doi =  }}</ref>