1. Competitive interactions in heterogeneous cell populations

Competition between cells is a phenomenon originally identified in development that results in the elimination of less fit cells (the loser cells) from a tissue. The viability of loser cells depends strongly on context: when they are cultured alone, they thrive but, when they are cultured in a mixed population, they are eliminated by cells with greater fitness. To address this we have combined long-term automated microscopy, deep learning and single cell tracking to decipher how single-cell behaviour determines tissue make-up during competition (Bove et al. Mol. Biol. Cell 2017).

2. Single-molecule studies of the Nuclear Pore Complex

The eukaryotic cell is characterised by containing an envelope bound nucleus, separating the genome and the remainder of the cell. Massive protein channels, known as Nuclear Pore Complexes (NPCs), span the membrane and mediate all molecular traffic. This function is critical to normal cellular function, in that the spatial and temporal localisation of factors such as transcription factors must be tightly regulated.

We were the first to develop bespoke semiconductor nanocrystal probes, employing single particle tracking, to monitor single cargos as they transit through the NPC in real-time (Lowe et al. Nature 2010). Using fluorescence fluctuation spectroscopy and super-resolution imaging we described to nanometre scale organisation of nuclear transport receptors (NTRs) within intact NPCs (Jeremy et al. Meth. Mol. Biol. 2016), and showed that the multivalent binding of NTRs is likely involved in forming the permeability barrier within the NPC, acting as a reversible molecular staple between FG-nup domains in vitro (Lowe et al. eLife 2015).

3. Micro-optical properties of cyanobacteria

Many prokaryotes move directionally in response to a chemical or physical stimulus. Synechocystis cells do not respond to a spatiotemporal gradient in light intensity, but rather they directly and accurately sense the position of a light source. We show that directional light sensing is possible because Synechocystis cells act as spherical microlenses, allowing the cell to see a light source and move towards it. A high-resolution image of the light source is focused on the edge of the cell opposite to the source, triggering movement away from the focused spot. Spherical cyanobacteria are probably the world’s smallest and oldest example of a camera eye (Schuergers et al. eLife 2016).

Press coverage: BBC News, Wired, The Telegraph, The Atlantic, Science, The Economist, Nature, Physics World

4. Methods and tool development

We are developing super-resolution microscopy and single particle tracking approaches to study reactions in living cells. We are also interested in understanding larger scale functional and phenotypic changes in populations of cells. We have been developing software for image classification, segmentation and tracking, based on computer vision and machine learning approaches to data analysis. See more...