Sporulation and enterotoxin regulation by sigma factors in Clostridium perfringens

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dc.contributor.authorHarry, Kathryn Heleneen
dc.contributor.committeechairMelville, Stephen B.en
dc.contributor.committeememberChen, Jiann-Shinen
dc.contributor.committeememberSchubot, Florian D.en
dc.contributor.committeememberYang, Zhaominen
dc.contributor.departmentBiologyen
dc.date.accessioned2014-03-14T21:35:41Zen
dc.date.adate2008-06-04en
dc.date.available2014-03-14T21:35:41Zen
dc.date.issued2008-04-28en
dc.date.rdate2008-06-04en
dc.date.sdate2008-05-07en
dc.description.abstractClostridium perfringens is a leading cause of food poisoning annually in the United States. Ingested C. perfringens vegetative cells respond to the acidic conditions of the stomach by initiating sporulation. The process of sporulation is essential in the formation of an enterotoxin (CPE) that is responsible for the symptoms of acute food poisoning. During sporulation, the cell must differentiate into the mother cell and the forespore. Studies in Bacillus subtilis have shown that gene expression during sporulation is compartmentalized, with different genes expressed in the mother cell and the forespore. The cell-specific RNA polymerase sigma factors coordinate the development of the differentiating cell. These sigma factors are Ï F, Ï E, Ï G, and Ï K. The C. perfringens cpe gene, encoding the enterotoxin CPE, is transcribed from three promoters, P1, P2, and P3. P2 and P3 were previously proposed to be Ï E-dependent, and P1 was proposed to be Ï K-dependent based on consensus recognition sequences. In this study, mutations were introduced into the sigE and sigK genes of C. perfringens. In the sigE and sigK mutants, promoter fusion assays indicated that there was no transcription of cpe in either mutant. We also determined through transcriptional analyses that Ï E-associated RNA polymerase and Ï K-associated RNA polymerase co-regulate the transcription of each other. RT-PCR analyses indicated that Ï K is a very early acting sigma factor. The evidence provided here shows that the regulation of sporulation in C. perfringens is not the same as it is in B. subtilis, as previously proposed.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-05072008-115555en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-05072008-115555/en
dc.identifier.urihttp://hdl.handle.net/10919/42517en
dc.publisherVirginia Techen
dc.relation.haspartHarryThesis.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectClostridium perfringensen
dc.subjectsporulationen
dc.subjectsigma factorsen
dc.subjectCPEen
dc.subjectfood poisoningen
dc.titleSporulation and enterotoxin regulation by sigma factors in Clostridium perfringensen
dc.typeThesisen
thesis.degree.disciplineBiologyen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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