Social Motility

Social Dynamics, Signaling, and Surface Motility in Cyanobacteria: Integrating Models and Experiment

Microorganisms live in environments that are often severely limited in resources or in which vital inputs such as light and nutrients fluctuate unpredictably. Thus, their ability to sense and respond quickly to environmental cues is finely regulated and well-evolved. We are particularly interested in the exquisite ability of photosynthetic microorganisms, like cyanobacteria, to sense and respond to light, in a process called phototaxis. Based on our preliminary studies, we hypothesize that the motility of cyanobacteria in space and time is a result of an intricate interplay between the characteristics of an individual bacterium and the social dynamics of the colony. We believe that a better understanding of these complex phenomena can greatly benefit from collaboration between biologists who use a range of genetic and biochemical tools to dissect the process of phototaxis, and mathematicians who can develop models that integrate individual cellular behavior with social behavior (which may be difficult to monitor at a biological level).

Our initial collaboration integrated data taken from long duration time-lapse video microscopy movies of phototactic cyanobacterial cells (made in the Bhaya lab) and new mathematical models that were developed by Levy’s group. This was particularly exciting given that the models were based on a set of assumptions that provide biological insights and alerted us to the possible advantages of consolidating this approach.

Here, we intend to extend this collaborative research with the following specific aims:

  1. To experimentally monitor surface dependent motility of Synechocystis sp. under defined, biologically relevant conditions.
  2. To derive, study, and test mathematical models that will be integrated with the new biological data.
  3. To use phototaxis mutants to extend and refine mathematical models in the context of biologically relevant questions.