Master Thesis Proposal

Proposed Topic

Testing methods for the isolation of novel Iron bacteria phages from environmental samples (e.g. Odertal National Park).

Project summary

Bacteriophages are viruses that infect bacteria, and in countries like Georgia are commonly used for the control bacterial infections in a treatment known as phage therapy. In recent years, the increase of antibiotic resistance of pathogenic bacteria has made Western countries, including Germany, to regain interest in phage therapy (Lin et al., 2017). This interest is not only limited to phage therapy but extended to the use of phages to control undesired and uncontrolled bacteria in other fields (i.e. biocontrol mediated by phages) like in agriculture and food industry (Abedon et al., 2017; Buttimer et al., 2017). There are numerous benefits of using phages for biocontrol including low toxicity, environmentally friendly and low-costly (Loc-Carrillo & Abedon, 2011). These characteristics are very appealing for the control, for example, of bacteria growing in groundwater water wells where the accumulation of bacteria and biogenic materials causes clogging and ultimately the spoilage of the wells. Among others, iron oxidiser bacteria (FeOB) are common clogging microorganisms. Therefore, we aim to use phages for the biocontrol of FeOB. That is, nevertheless, not a straightforward process because the physiology and ecology of FeOB bacteria display many methodological challenges for phage isolation (e.g. aggregation and formation of iron shields around cells).  On the one hand, available techniques might fail on the isolation. On the other hand, recent studies suggest that current standard methods for phage isolation are possibly biased to a few specific phage groups (Kauffman et al., 2018). Hence, the purpose of this thesis will be to establish FeOB phages isolation methods and to evaluate which methods fit better for our interest.

Methodology:

The methods used during this project will principally focus on the isolation of novel phages from the environment.  The technical focus of this thesis will rely upon "Phage Methods" including phage isolation, propagation, concentration and host-range testing techniques.

The student will have the chance to learn about phage and FeOB biology and ecology. Furthermore, he/she will have the opportunity, and will be encouraged to propose and accomplish some experiments of his/her own ideas that fall within the scope of the project.

Additionally, depending on the success of the project and availability, it will also be possible to characterise a phage fully.

References / Bibliography:

Abedon, S.T., García, P., Mullany, P. & Aminov, R. (2017) Editorial: PhageTherapy: Past, Present and Future. Front. Microbiol. 8: 981. doi: 10.3389/fmicb.2017.00981

Buttimer, C., McAuliffe, O., Ross, R. P., Hill, C., O’Mahony, J. & Coffey, A. (2017) Bacteriophages and Bacterial Plant Diseases. Front. Microbiol 8: 34. doi: 10.3389/fmicb.2017.00034

Kauffman, K., Hussain, F.A. Yang, J., Arevalo, P., Brown, J.M., Chang, W. K., VanInsberghe, D., Elsherbini, J., Sharma, R.S., Cutler, M.B., Kelly, L., & Polz, M.F. (2018) A major lineage of non-tailed dsDNA viruses as unrecognized killers of marine bacteria. Nature 554, 118. doi: 0.1038/nature25474

Lin, D. M., Koskella, B., & Lin, H. C. (2017). Phage therapy: An alternative to antibiotics in the age of multi-drug resistance. World Journal of Gastrointestinal Pharmacology and Therapeutics, 8(3), 162–173. doi.org/10.4292/wjgpt.v8.i3.162

Loc-Carrillo, C., & Abedon, S. T. (2011). Pros and cons of phage therapy. Bacteriophage, 1(2), 111–114. doi.org/10.4161/bact.1.2.14590