Motion-Signal Correlation and Decision Making in the Social Amoeba Dictyostelium discoideum

Abstract

Collective behavior and pattern formation are ubiquitous phenomena at all levels of biological complexity, yet they remain incompletely understood. One powerful model system for studying collective behavior of individual cells is the social amoeba Dictyostelium discoideum, in which single cells aggregate to form a multicellular structure during conditions of starvation through signaling by cyclic adenosine monophosphate (cAMP). This thesis improves on current experimental and analytic techniques to develop a system for analysis of cAMP signaling at both the population and single-cell levels with unprecedented resolution. This approach demonstrates a strong correlation between cAMP signaling and individual cellular responses, with cells closer to aggregation centers showing an earlier response to cAMP. These results add to current understanding of how cAMP signaling a ects individual cell decision making and how aggregation centers are formed. In addition, modeling the cAMP signals through circular waves has begun to elucidate how these chemical signals translate into cellular motion. Thus, this work not only builds on current research investigating the dynamics underlying cellular self-organization in D. discoideum but also provides an improved experimental and analytic approach that can be applied to a variety of research questions in collective behavior and pattern formation.