Project description:Creation of Transposon libraries within 6 C. jejuni, 4 C. coli, 1 C. hyointestinalis and1 C. lari species. A mariner transposon was used to create libraries, these were sequenced and analysed using the Biotradis pipeline. This allowed us to investigate essential genes for each strain, across strains and between species.
Project description:Campylobacter species are the major cause of bacterial gastroenteritis. As there is no effective vaccine, combined with the rapid increase in antimicrobial resistant strains, there is a need to identify new targets for intervention. Essential genes are those that are necessary for growth and/or survival, making these attractive targets. In this study, comprehensive transposon mutant libraries were created in six C. jejuni strains, four C. coli strains and one C. lari and C. hyointestinalis strain, allowing for those genes that cannot tolerate a transposon insertion being called as essential. Comparison of essential gene lists using core genome analysis can highlight those genes which are common across multiple strains and/or species. Comparison of C. jejuni and C. coli, the two species that cause the most disease, identified 316 essential genes. Genes of interest highlighted members of the purine pathway being essential for C. jejuni whilst also finding that a functional potassium uptake system is essential. Protein-protein interaction networks using these essential gene lists also highlighted proteins in the purine pathway being major 'hub' proteins which have a large number of interactors across the network. When adding in two more species (C. lari and C. hyointestinalis) the essential gene list reduces to 261. Within these 261 essential genes, there are many genes that have been found to be essential in other bacteria. These include htrB and PEB4, which have previously been found as core virulence genes across Campylobacter species in other studies. There were 21 genes which have no known function with eight of these being associated with the membrane. These surface-associated essential genes may provide attractive targets. The essential gene lists presented will help to prioritise targets for the development of novel therapeutic and preventative interventions.
Project description:The experiment aimed to find how Campylobacter responds to oxidative stress using hydrogen peroxide. This was done by using previously made TraDIS libraries (https://bmcmicrobiol.biomedcentral.com/articles/10.1186/s12866-023-02835-8) and putting them under oxidative stress. The strains used were C. jejuni 11168, C. coli 15-537360 and C. coli CCN182.
Project description:Transcriptional profile of C. jejuni NCTC11168 while growing in MEM medium containing L-fucose. We hypothesize that certain C. jejuni strains, containing A certain genomic island, have acquired the ability to metabolize fucose. This study demonstrates the transcriptional profile C. jejuni growth while utilizing fucose.
Project description:While growing in the human intestine, C. jejuni grows within the mucus layer. The largest constituents of this layer are the large mucin glycoproteins. A transcriptomic profile of C. jejuni NCTC11168 growing in a mucin-containing minimal medium seeks to describe the effect of the presence of mucin proteins on the transcriptome of C. jejuni.
Project description:Transcriptional regulation mediates adaptation of pathogens to environmental stimuli and is important for host colonisation. The Campylobacter jejuni genome sequence reveals a surprisingly small set of regulators, mostly of unknown function, suggesting an intricate regulatory network. Interestingly, C. jejuni lacks the homologues of ubiquitous regulators involved in stress response found in many other Gram-negative bacteria. Nonetheless, cj1000 is predicted to code for the sole LysR-type regulator in the C. jejuni genome, and thus may be involved in major adaptation pathways. A cj1000 mutant strain was constructed and found to be attenuated in its ability to colonise 1-day old chicks. Complementation of cj1000 mutation restored the colonisation ability to that of wild type levels. The mutant strain was also outcompeted in a competitive colonisation assay of the piglet intestine. High resolution oxygraphy was carried out for the first time on C. jejuni and revealed a role for Cj1000 in controlling O2 consumption. Furthermore, microarray analysis of the cj1000 mutant revealed both direct and indirect regulatory targets, including genes involved in energy metabolism and oxidative stress defences. These results highlight the importance of Cj1000 regulation in host colonisation and in major physiological pathways.
Project description:The screening of a cDNA derived expression library of Campylobacter jejuni NCTC 11168 expressed in E. coli using a fusion construct and specific HaloTag interaction to a modified surface is shown. 1536 different clones were screened including positive (hisJ, cjaA, peb1a) and negative (argC, pyrC, gapA) reference proteins. The goal of the screening was to identify potential novel immunogenic proteins from C. jejuni by selecting clones showing a high signal intensity in comparison to the known antigens used as positive markers. Afterwards, the most promising clones were sequenced to identify the gene and corresponding protein, and these proteins were then investigated further. Consequently, 22 novel immunogenic proteins could be identified.