Please use this identifier to cite or link to this item:
Title: Environmental regulation of the pneumolysin gene of Streptococcus pneumoniae
Authors: Manning, Georgina.
Award date: 1997
Presented at: University of Leicester
Abstract: Streptococcus pneumoniae (the pneumococcus), a major cause of morbidity and mortality throughout the world, is responsible for the life threatening diseases pneumonia and meningitis. Numerous virulence factors are believed to be involved in the disease process, including the cytolytic toxin pneumolysin. This toxin has been studied in detail in terms of its structure and function. Little is known about the expression and regulation of this toxin. It is also unknown whether any of the other virulence factors are regulated.;Environmental regulation of the pneumolysin gene was studied. The effect of temperature, adding serum to the growth medium, pH, and iron, on the expression of the pneumolysin gene was studied. Initial experiments, whereby toxin levels were measured directly by ELISA, indicated that pneumolysin expression is increased in a low iron environment, compared with an iron replete medium.;A luciferase and a cat reporter fusion, with DNA from immediately upstream of the pneumolysin gene, confirmed the observation that pneumolysin expression is increased in a low iron environment.;Regulation of the pneumolysin gene was also studied at the transcriptional level. Northern blot analysis revealed that the pneumolysin gene is transcribed as part of a polycistronic message along with two open reading frames located upstream and possibly a third located downstream. Primer extension analysis identified a putative transcriptional start site 90bp upstream of ORF1 and another 300bp upstream of the pneumolysin gene. A model of the proposed mechanism of regulation of pneumolysin expression is presented.
Type: Thesis
Level: Doctoral
Qualification: PhD
Rights: Copyright © the author. All rights reserved.
Appears in Collections:Theses, Dept. of Biology
Leicester Theses

Files in This Item:
File Description SizeFormat 
U104177.pdf12.39 MBAdobe PDFView/Open

Items in LRA are protected by copyright, with all rights reserved, unless otherwise indicated.