From stress to success: how actinobacteria exploit life witout a cell wall

Ongenae, V.M.A. (2025)

Doctoral Thesis

The aim of this thesis was to study phage infection in Streptomyces, focused on cell wall-deficient cells. Bacteriophages (or phages in short) attach to the cell wall of bacteria after which they replicate and lyse the host cell. We have discovered that bacteria are able to shed their cell wall in response to phage infection in osmoprotective medium and can thereby escape an infection by phages. Our research was focused on Streptomyces species, but even Escherichia coli and Bacillus subtilis could shed their cell wall in response to phage infection, which should be taken into account when researching the effects of phage therapy. The results of this thesis contribute to a better understanding of phage infection dynamics in multicellular bacteria and the effect of cell wall-deficient bacteria associated with bacteriophages.

• Bacteriophages
• Streptomyces
• Cell wall-deficiency
• Cell wall
• L-forms
• Phage defense
• Phage therapy

• All authors: Ongenae, V.M.A.
• Supervisor: Claessen, D.; Briegel, A.
• Committee: Meijer, A.H.; Spaink, H.P.; Barona Gomez, F.; Frunzke, J.; Brouns, S.J.J.
• Qualification: Doctor (dr.)
• Awarding Institution: Institute of Biology (IBL), Faculty of Science, Leiden University
• Date: 2025-03-11
• ISBN (print): 9789465069678