The basis of my research has been to identify and characterise the function of ‘<i>E. coli</i> specific’ genes. <i>E. coli</i> specific genes were identified after comparing 33 gamma proteobacterial genomes at the Microbial Genome Database (MBGD). The database was used to investigate the change in the number of <i>E. coli</i> specific genes since the completion of the first <i>E. coli</i> genome in 1997. Forty nine selected <i>E. coli </i>specific genes were deleted in 38 separate deletion events on the genome of the model <i>E. coli </i>K-12 MG1655 using the modified pKO3 deletion procedure. Gene expression levels and patterns in various phases of growth in LB broth were measured and are reported here. Mutant and parent strains were tested for growth on a variety of conditions in agar based media. A mutant of the <i>yigE</i> ORF was found to be sensitive to high concentrations of nickel and cobalt in the growth medium. Mutation of the <i>E. coli</i> specific <i>htrC</i> gene showed no temperature sensitivity as reported in published literature and is shown here to play no part in the heat shock response of <i>E. coli. </i>The chromosomal position of the acetate utilisation gene <i>ackB</i> is experimentally demonstrated to be close to the known acetate kinase gene <i>ackA</i> at 50 minutes on the K-12 chromosome. Mutations in ORFs <i>yceP, ydeK </i>and <i>ygjMN</i> made the mutants sensitive to high levels of the basic dye gentian violet. This study shows that the group of genes specific to <i>E. coli</i> targeted here are expressed, show different patterns of expression and some are phenotypically functional. This study draws attention to a fraction of genes whose functional contribution to <i>E. coli</i> may have been underestimated due to their poor conservation in genomes other than <i>E. coli.</i>
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:662824 |
| Date | January 2004 |
| Creators | Thacker, Zubin |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/11457 |
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