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Full-Text Articles in Molecular Biology
Sigma Factor N: A Novel Regulator Of Acid Resistance And Locus Of Enterocyte Effacement In Escherichia Coli O157:H7, Avishek Mitra
Sigma Factor N: A Novel Regulator Of Acid Resistance And Locus Of Enterocyte Effacement In Escherichia Coli O157:H7, Avishek Mitra
USF Tampa 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 rpoN (σN) …
Sigma Factor N (Σn): A Novel Regulator Of Extreme Acid Resistance In Enterohemorrhagic E. Coli O157:H7, Pamela Ann Fay
Sigma Factor N (Σn): A Novel Regulator Of Extreme Acid Resistance In Enterohemorrhagic E. Coli O157:H7, Pamela Ann Fay
USF Tampa 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 …