<i>Campylobacter jejuni</i> is the most commonly recognized cause of bacterial gastroenteritis in man and also infects cattle, sheep and poultry. Publishing of the genome sequence of <i>Campylobacter jejuni 11168</i> (Parkhill, 2000) revealed the presence of only one cytochrome P450. Its coding sequence (Cj411c) is located in an operon involved in sugar and cell surface biosynthesis. The gene name is Cj1411c, is 1359 bp long and encodes 453 aa. The sequence is strictly conserved in <i>Campylobacter jejuni</i> RM221. Recombinant P450 was expressed in <i>E. coli</i> and showed the 450 nm peak in the presence of CO indicating the correct folding. The protein was partially purified to about 70% purity. By deleting the P450 gene from the <i>Campylobacter jejuni 11168</i> genome clear changes in cell morphology were identified, cells becoming wider and shorter. The capsular sugar profile of the NC1 knockout strain reveals the presence of arabinose which was not found in the wild type strain. The arabinose was identified by both HPLC and NMR. The phenotype studies showed clear differences between NC1 and WT cells: NC1 cells are less resistant to starvation in the stationary phase; by exposure to the atmospheric oxygen 36.47% of the wild type cells survived after 24 hours and only 16.61% of the NC1 cells survived; by growing the NC1 cells in competition with the WT cells the growth rate of NC1 cells approximately 10x lower than the WT; NC1 cells were proved to be less resistant to high temperature, more resistant to low temperatures and pH. By analysing the results obtained with NaC1 and glycerol we have determined that it is not the osmotic pressure that is affecting the growth of <i>Campylobacter </i>and the differences between the WT and NC1 strain might be related with changes in cell surface components.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:644990 |
| Date | January 2005 |
| Creators | Corcionivoschi, Nicolae |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/13463 |
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