Bacteria, like all other cells, stay alive by maintaining adequate supplies of free energy. Under various external stresses, bacteria attempt to stay viable by distributing the available energy to processes essential for coping with the challenge, while simultaneously maintaining core cellular functions. However, little research has been done on understanding the free energy coordination.
In this project, we will take a multidisciplinary approach to investigate bacterial strategies for free energy coordination by directly measuring the free energy dynamics under stress conditions. Specifically, we will start with dormant states, where the bacterial cells are alive, but not dividing, which are known to be low in energy. We will be asking are different dormancies energetically equivalent states, and if not, how exactly are the energy levels relevant for cell survival.
During the project, you will use a range of biophysical assays for single-cell measurements of the two main sources of free energy we developed in the lab: the proton motive force (PMF) and the internal adenosine triphosphate (ATP) levels. The PMF is a direct consequence of the activity of the electron transport chain and serves as the energy source driving numerous cellular processes: ATP production, motility and active membrane transport. The ATP molecule is the energy ‘currency’ of living organisms used for biosynthesis and ABC transport pathways. The biophysical assays for single-cell PMF and ATP measurements we develop are suited for simultaneous monitoring of changes in both PMF and ATP while exposing the cells to various external stresses.
Based on this unique data set, which will be the time course information on the two main energy sources in dormant cells, we will build a mathematical model that will allow us to identify different strategies to sustain free energy. Time providing, apart from dormant cells we will extend the range of stressed conditions, by using a range of different killing agents with different targets and mechanisms (such as different antibiotics).
A simplistic view of life is to think of it as a process that transforms external materials into cellular components based on genetic information and by transducing energy. While significant efforts by the research community are going into understanding the flow of genetic information less has been done to elucidate energy transduction. As the free energy state in living organisms also transmits information, our overall objective is to uncover the fundamental principles behind the preservation of free energy and to offer an operational definition of ‘dead’ and ‘alive’ grounded in the biophysics of free energy flows.
During the project, you will work in an interdisciplinary team composed of physicist, engineers, biotechnologists and biologists, and will be embedded in the Synthetic and Systems Biology Centre at the University of Edinburgh. The Centre offers a great range of expertise in quantitative biology approaches, but also host internationally renewed guests on regular basis, all of whom you will have the opportunity to interact with during the course of the project. http://pilizotalab.bio.ed.ac.uk/ http://www.synthsys.ed.ac.uk/our-centre
Krasnopeeva E, Lo CJ, Pilizota T**. Single-cell bacterial electrophysiology reveals mechanisms of stress induced damage. Biophys J 2019;116(12): 2390-2399
Arlt J**, Martinez V A, Dawson A, Pilizota T and Poon W C K. Painting with light-powered bacteria. Nature Communications 2018;9: 768
Mancini L, Tian T*, Terradot G*, Pu Y, Li Y, Lo CJ, Bai F, Pilizota T** A general work-flow for characterization of Nernstian dyes and their effects on bacterial physiology, (Biophys J, In press)