| Summary: | Bacteriocins are antibacterial, proteinaceous substances that mediate microbial
dynamics. Bacteriocin production is a highly disseminated property among all
major lineages of bacteria, including Shigella. In this paper,
we addressed the purification and characterisation of a bacteriocin produced by
a Shigella sonnei strain (SS9) isolated from a child with acute
diarrhoea. The substance was purified through ammonium-sulphate precipitation
and sequential steps of chromatography. The intracellular fraction obtained at
75% ammonium sulphate maintained activity following exposure to pH values from
1-11 and storage at -80ºC for more than two years and was inactivated by high
temperatures and proteases. The molecular mass of the purified bacteriocin was
determined by mass spectrometry to be 18.56 kDa. The N-terminal sequence of the
bacteriocin did not match any other antibacterial proteins described. A putative
new bacteriocin produced by S. sonnei has been detected. This
bacteriocin may represent a newly described protein or a previously described
protein with a newly detected function. Considering that SS9 expresses
antagonism against other diarrhoeagenic bacteria, the bacteriocin may contribute
to S. sonnei virulence and is potentially applicable to either
preventing or controlling diarrhoeal disease.
|
|---|