Uncovering Transcriptional States in Bacterial Biofilms and Planktonic Populations

PhD defence by Siwei Liang

Assessment Committee

Professor Søren J Sørensen, Biology, University of Copenhagen (Chairperson)
Professor Timothy Vogel, University of Lyon
Professor Andreas Schramm, University of Århus

Supervisors

Professor Mette Burmølle
Associate Professor Jonas Stenløkke Madsen


Department

Department of Biology

Place

Building: Building 1, Room: Auditorium A, Universitetsparken 15, 2100 København Ø

Email address to gain access to the thesis: burmolle@bio.ku.dk.
You will either receive a copy of the thesis or be informed where you can read a physical copy.
Recipients of copies of the thesis are not allowed to share or distribute it due to copyright compliance.

Short description of the thesis

This PhD thesis explores how genetically similar bacteria can display heterogeneity, both as free-living cells and within biofilms. Such hidden heterogeneity can influence how bacterial populations grow, interact, and survive stressful conditions. The thesis combines conceptual frameworks, fluorescent biosensors, cell sorting, biofilm imaging, bulk RNA sequencing, and exploratory single-cell transcriptomics. It investigates transient low-energy subpopulations in Escherichia coli, interactions between CAUTI-derived Pseudomonas aeruginosa and Klebsiella oxytoca in dual-species biofilms, and the challenges of resolving bacterial gene expression at single-cell resolution. Together, this work advances our understanding of bacterial heterogeneity and the transcriptional states that shape microbial survival and community behavior.