Bacteria can form communities on a surface, the behaviors of cells spatially and temporally depend on their neighbors, sharply contrasting with that of the planktonic cells. Understanding behavior of bacterial community is much more complicate than that of a single cell. In this context, the key problem is: How do you characterize the bacterial communities? We don't want to solve this problem directly, instead, we asked another question - How bacteria build their communities from the individuals? Knowing this definitely can help us to understand the bacterial communities, including the cooperation, competition and communication.
We developed a method (called topological tracking algorithm) that can be used to track how bacteria build their communities from the individuals. The new algorithm can automatically quantify the behaviors of single cells, including motility, attaching or detaching on the surface, division and clustering. We also utilized the modern mathematical tools (Graph Theory or Network Theory) to quantify the collective behaviors as well as the structure of bacterial communities.