Social Motility

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

Microorganisms live in environments that are often severely resource-limited or where vital inputs such as light and nutrients fluctuate unpredictably. Thus, their ability to sense and respond quickly to environmental cues is carefully regulated. We are particularly interested in the exquisite ability of photosynthetic microorganisms, like cyanobacteria, to sense and respond to light, in a process called phototaxis. We hypothesize that the motility is an intricate interplay between the individual bacterial behavior and the social dynamics of the colony.

We believe that a better understanding of these complex phenomena can greatly benefit from collaboration between experimental biologists who use genetic and biochemical tools and those with theoretical training. This allows us to develop testable models that integrate individual cellular behavior with emergent social behavior (which may be difficult to monitor at a biological level).

In a fruitful collaboration data taken from long duration time-lapse video microscopy movies of phototactic cyanobacterial cells (made in the Bhaya lab) were used to build new mathematical models developed in the group of Doron Levy. This has provided us models based on a set of assumptions that provide biological insights and has alerted us to the possible advantages of consolidating this approach. We have continued this approach in collaboration with the group of K. C. Huang  at the Department of Bioengineering, Stanford University.

Collaborative research has 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.

View videos of phototaxis and other plant photo-movements. 

This research was funded by NSF.