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A Novel Bacterial Defence System against Antimicrobial Peptides: Implications for Host Colonisation in the Foodborne Pathogen Campylobacter jejuni


<p>The main objective of this project is to determine the function of each of the components involved in the complex CAMP resistance system and its contribution to the colonisation of the chicken.</p>

<p>The campylobacter CAMP resistance system consists of a membrane-bound sensor protein and a small DNA binding protein which controls the expression of three genes encoding an inner membrane protein, an outer membrane anchored lipoprotein and a periplasmic protein, as well as certain disulphide bond (Dsb) genes and genes that are involved in peptide transport and metabolism.</p>

This is the project approach:
<ul><li>investigate the mechanism of action of the lipoprotein and determine if it provides resistance to structurally diverse CAMPs</li>
<li>determine the roles of the uncharacterised genes</li>
<li>determine the role of the Dsb system in CAMP resistance</li>
<li>investigate the connection between peptide transport and CAMP transport and degradation</li>
<li>determine the importance of this system in vivo by chicken colonisation studies</li></ul>

More information

<p>Background: Campylobacter is the most commonly reported bacterial cause of infectious intestinal disease in the UK and the leading cause of bacterial food poisoning. Poultry are a major source of infection through undercooked meat. In order to begin to control campylobacter infection in chickens, and reduce the risk of food poisoning, it is important to have a better understanding of how campylobacter interacts with both its chicken and human host.</p>

<p>Cationic antimicrobial peptides (CAMPs) form a crucial defence against bacteria. CAMPs can be produced by the host, which insert themselves into the membrane of the bacteria to create a pore. The bacterial contents leak out of the pore which causes the death of the bacteria. However, campylobacter can be highly resistant to this action. This is because the bacterium uses a novel defence system, in the presence of these peptides, in which it positions a protein at its surface which binds the peptides and stops them getting to the cell membrane.</p>

<p>This project aims to understand the details of how campylobacter is able to sense and respond to antimicrobial peptides, how the binding protein works and the role of some other proteins that are also controlled by this system. </p>

University of Sheffield
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