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dc.contributor.authorVarga, John Josephen_US
dc.date.accessioned2014-03-14T20:19:16Z
dc.date.available2014-03-14T20:19:16Z
dc.date.issued2006-09-01en_US
dc.identifier.otheretd-11272006-133747en_US
dc.identifier.urihttp://hdl.handle.net/10919/29759
dc.description.abstractClostridium perfringens is a significant human pathogen, causing 250,000 cases of food poisoning in addition to several thousand potentially lethal cases of gas gangrene each year in the United States. Historically, work in this field has centered around toxin production, as C. perfringens can produce over 13 toxins. This work expands the knowledge of the starvation-response of C. perfringens, which includes several potential virulence factors, sporulation, motility and biofilm formation. Sporulation protects cells from a variety of stresses, including starvation. Efficient sporulation requires the transcriptional regulator CcpA, mediator of catabolite repression. Sporulation is repressed by glucose, but, surprisingly, in a CcpA-independent fashion. C. perfringens cells in a biofilm are resistant to a number of environmental stresses, including oxygen and antibiotics. Biofilm formation is repressed by glucose, and other carbohydrates, independently of CcpA. Gliding motility, a type four pili (TFP)-dependent phenomenon, affords C. perfringens with a mechanism for moving across a solid surface in response to carbohydrate starvation, while carbohydrates supplementation at high levels delay the initiation of the motility response. CcpA is required for the proper initiation of motility, a ccpA-C. perfringens strain showed a considerable increase in the time to initiation of motility on lactose and galactose, and was unable to move at all in the presence of glucose. Gliding motility represents the most significant finding of this work. TFP were previously undescribed in any Gram-positive bacterial species, and this work produced genetic evidence suggesting their presence in all members of the clostridia, and physical evidence for TFP-dependent gliding motility in a second species, C. beijerinckii.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartvarga-dissertation-11-30.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectsporulationen_US
dc.subjecttransposonen_US
dc.subjectfood poisoningen_US
dc.subjectCcpAen_US
dc.subjectmotilityen_US
dc.subjecttype four pilien_US
dc.subjectcomparative genomicsen_US
dc.subjectbiofilmen_US
dc.subjectClostridium perfringensen_US
dc.titleThe Role of CcpA in Regulating the Carbon-Starvation Response of Clostridium perfringensen_US
dc.typeDissertationen_US
dc.contributor.departmentBiological Sciencesen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineBiological Sciencesen_US
dc.contributor.committeechairMelville, Stephen B.en_US
dc.contributor.committeememberChen, Jiann-Shinen_US
dc.contributor.committeememberBoyle, Stephen M.en_US
dc.contributor.committeememberPopham, David L.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-11272006-133747/en_US
dc.date.sdate2006-11-27en_US
dc.date.rdate2008-12-01
dc.date.adate2006-12-01en_US


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