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Biochemistry, Biophysics, and Structural Biology Commons

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Molecular Biology

University of South Florida

EHEC

Publication Year

Articles 1 - 3 of 3

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Genetic Basis For The Virulence Of Enterohemorrhagic Escherichia Coli Strain Tw14359, Jason Kyle Morgan May 2014

Genetic Basis For The Virulence Of Enterohemorrhagic Escherichia Coli Strain Tw14359, Jason Kyle Morgan

Graduate Theses and Dissertations

Enterohemorrhagic Escherichia coli (EHEC) is a virulent pathotype of E. coli that is associated with major outbreaks of hemorrhagic colitis and the life-threatening kidney disease hemolytic uremic syndrome. For successful host colonization and attachment to the intestinal mucosa, EHEC requires the locus of enterocyte effacement (LEE) pathogenicity island, which encodes a type III secretion system (TTSS) responsible for secreting and translocating effector proteins into host colonocytes. Regulation of the LEE is primarily directed through the first operon, LEE1, encoding the locus encoded regulator (Ler), and occurs through the direct and indirect action of several regulators. The 2006 U.S. spinach ...


Sigma Factor N: A Novel Regulator Of Acid Resistance And Locus Of Enterocyte Effacement In Escherichia Coli O157:H7, Avishek Mitra Mar 2014

Sigma Factor N: A Novel Regulator Of Acid Resistance And Locus Of Enterocyte Effacement In Escherichia Coli O157:H7, Avishek Mitra

Graduate Theses and Dissertations

In enterohemorrhagic E. coli (EHEC) sigma factor N (σN) regulates glutamate-dependent acid resistance (GDAR) and the locus of enterocyte effacement (LEE), discrete genetic systems required for transmission and virulence of this intestinal pathogen. Regulation of these systems requires nitrogen regulatory protein C, NtrC, and is a consequence of NtrC/σN-dependent reduction in the activity of sigma factor S (σS). This study elucidates pathway components and stimuli for σN-directed regulation of GDAR and the LEE in EHEC. Deletion of fliZ, the product of which reduces σS activity, phenocopies rpoNN) and ntrC null ...


Sigma Factor N (Σn): A Novel Regulator Of Extreme Acid Resistance In Enterohemorrhagic E. Coli O157:H7, Pamela Ann Fay Jan 2012

Sigma Factor N (Σn): A Novel Regulator Of Extreme Acid Resistance In Enterohemorrhagic E. Coli O157:H7, Pamela Ann Fay

Graduate Theses and Dissertations

Extreme acid resistance contributes to the successful transmission of enterohemorrhagic E. coli (EHEC) through acidic food matrices and the stomach, allowing it to gain access to the intestine and elicit disease in humans. Alternative sigma factor N (σN, encoded by rpoN) was previously identified as a novel regulator of extreme acid resistance in EHEC. This study investigated the role for σN and co-expressed products of the rpoN operon in the acid resistance phenotype of EHEC. The results revealed that σN primarily controls acid resistance through repression of the glutamate-dependent acid resistance (GDAR) system through control of the ...