Pro studenty

The World Health Organisation (WHO) foresees that antibiotic-resistant (AR) bacteria will kill 10 million people annually by 2050. One of the most concerning AR species is Pseudomonas aeruginosa, which is an opportunistic pathogen that usually infects people with weakened immune systems. In recent years, the scientific community has turned to exploring bacteriophages as a mean to fight bacterial diseases, an alternative to antibiotics. Bacteriophages, or phages, are viruses that kill bacteria. This could thus prevent the health crisis foreseen by the WHO.

For an efficient therapeutic use of phages, we need to know more about their life cycle. One of the key steps of the cycle happens in the beginning. In the presence of the bacterium, the phage contracts its tail and ejects its genome into the bacterium. Now, the infection begins. In our laboratory, we can study this step by looking at the changes in the ultrastructure of phages.

The aim of this project is to induce the tail contraction of the phage phiKZ without the presence of the bacterium. PhiKZ is a phage infecting P. aeruginosa and we are currently studying its structure before the tail contraction. However, in order to study the genome ejection step and the structural changes that occur, the conditions for its induction need to be established.

In this project, the student will learn the procedure for propagation and purification of the phage phiKZ, including media preparation for bacterial and phage growth. The student will use ultracentrifugation to separate phages from impurities and verify the purity of the sample by electron microscopy and plaque assays. Additionally, the student will test various conditions of temperature, ionic strength, or pH, to trigger the tail contraction without the presence of the bacterium.