Thursday, August 26, 2010

Defining the link between enterotoxin production and sporulation in C. perfringens

The second most common cause of bacterial foodborne illness is Clostridium perfringens type A. These isolates produce an enterotoxin (CPE), and an estimated 250,000 cases of resultant food poisoning occur annually in the U.S. Forty years ago, it was postulated that sporulation and enterotoxin production were linked and, in fact, C. perfringens type A isolates only produce CPE during sporulation.

Four sigma factors mediate sporulation in C. perfringens; however, the exact roles of two of them (SigF and SigG) are unknown. After confirming that sporulating wild-type SM101 cultures produce SigF and SigG, Li and McClane prepared isogenic sigF or sigG null mutants. They used the MasterPure™ Gram-Positive DNA Purification Kit to isolate DNA for Southern blotting, to confirm the presence of a single intron insertion in the SM101::sigF and SM101::sigG mutants. The detection of alternative sigma factor production by Western blot analysis was aided by Ready-Lyse™ Lysozyme. The authors concluded that all four sigma factors are needed for sporulation, but only SigE, SigF, and SigK are needed for synthesis of CPE. The results of this study indicate a previously unappreciated level of complexity for the regulation of cpe transcription.

ResearchBlogging.orgLi, J. and McClane, B. (2010). Evaluating the Involvement of Alternative Sigma Factors SigF and SigG in Clostridium perfringens Sporulation and Enterotoxin Synthesis Infect. Immun. : 10.1128/IAI.00528-10

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