I will give an overview of some recent work in my lab, where we have used high-speed cameras and computational image processing to gain new insight into biological systems. The first area is collective motion in a population of swimming bacteria (specifically E. coli). We adopt ideas from light scattering to measure chemotactic drift in thousands of bacteria at the same time. We compare our results to a parameter-free analytical model of chemotaxis and find excellent agreement . Secondly, we have developed a form of high-speed holographic microscopy to image swimming cells in three dimensions. I will give a brief overview of several systems that we have studied: microgametes of the genus Plasmodium (which causes malaria), chemotaxis in sea urchin sperm cells, and populations of bacteria/archaea. The Plasmodium microgametes are essentially isolated, swimming flagella; by looking at the waves that pass along microgametes as they swim, we uncovered something surprising in the relationship between the swimming stroke and the underlying molecular structure . In conjunction with groups in Bonn and Dresden, we studied the chemosensory system in sea urchin sperm cells. We used a relatively simple model to relate the cells’ internal signalling state to their steering response, as they swim in spatially-controlled 3D chemical gradients . Lastly, we have been tracking populations of bacteria and archaea in three dimensions. This work is at an early stage, but I will talk about where we intend to go with it, and give some preliminary results.
 Colin et al., J. Roy. Soc. Interface 11(98) p. 20140486 (2014)
 Wilson et al., Proc. Natl. Acad. Sci. USA 110(47) p.18769-18774 (2013)
 Jikeli et al., Nat. Comms. 6 p.7985 (2015)
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..