Temperature regulation of the heme transport system in Escherichia coli


Temperature regulation of the heme transport system in Escherichia coli

Show simple record

dc.contributor.advisor Shelley Payne
dc.creator Wygoda, Jennifer
dc.date.accessioned 2011-09-07T15:31:18Z
dc.date.available 2011-09-07T15:31:18Z
dc.date.created 2010
dc.date.issued 2011-09-07
dc.identifier.uri http://hdl.handle.net/2152/13472
dc.description.abstract Temperature regulation of the heme transport system is important, as it allows the microorganism to sense that it has entered the mammalian host environment of 37° C and adjust the expression of its iron-transport and virulence genes accordingly. It is known that expression of shuA, a gene encoding the outer membrane receptor that binds heme, is regulated by the amount of iron in the environment, yet little is known about the role of temperature in the regulation of this system. To study the effect of temperature on the activity of the shuA promoter, E. coli was transformed with a plasmid containing the shuA promoter fused to the reporter gene lacZ and transformed cultures were assayed for ß-galactosidase activity as an indirect measure of shuA promoter activity. Results suggest that shuA promoter activity is temperature regulated, with increased activity at 37° C compared to 30° C. The histone-like nucleoid structuring protein (H-NS) is a global regulator in E. coli, and it has been shown to respond to environmental signals, including osmolarity, temperature, and pH. To test the hypothesis that H-NS is mediating shuA promoter activity, gene expression was measured in an hns mutant and wild-type strain. Results indicate that H-NS is partially, but not solely, responsible for the temperature regulation of shuA. In a separate investigation, the possibility of exploiting the presence of heme transport systems in pathogenic bacteria to deliver toxic compounds to the pathogen was tested. The toxicity of MGd and MGd-18-crown-6 texaphyrin compounds to E. coli expressing the heme transport system was examined. Results suggest that texaphyrin compounds are not toxic to E. coli growth.
dc.language.iso eng
dc.subject College of Natural Sciences
dc.subject heme transport system
dc.subject Escherichia coli
dc.subject shuA
dc.subject histone-like nucleoid structuring protein
dc.subject temperature regulation
dc.title Temperature regulation of the heme transport system in Escherichia coli
dc.type Thesis
dc.description.department Biological Sciences, School of

Files in this work

Download File: Wygoda_Bio_10.pdf
Size: 406.2Kb
Format: application/pdf

This work appears in the following Collection(s)

Show simple record

Advanced Search


My Account