A Numerical Model of Vibrio fischeri Growth and Intraspecific Competition

Yuexia Lin, Harvard University

Photo of Yuexia Lin

E. scolopes squids are colonized with V. fischeri bacteria, a symbiosis that serves as a model system for studying host-microbe interactions. Wild-caught adult squids harbor multiple strains of V. fischeri that engage in intraspecific competition during initial host colonization. However, little is known about how competing strains interact at the single-cell level to influence their spatial structure as they coexist. When grown on agar surfaces, two competing strains form segregated spatial patterns that are dependent on their ability to kill one another. We developed an experimentally informed, multi-agent numerical model of cell growth, division and death in two dimensions that can simulate intercellular interactions and environmental factors. In particular, the model accounts for intraspecific competition via mutual killing and differences in growth. This computational model is used to explore conditions that allow a diversity of strains to coexist and to investigate the spatiotemporal properties of this coexistence. We present results that demonstrate the method's ability to capture the segregated patterns and their length scales, and explore parameter space that is hard to access in experiments.

Abstract Author(s): Yuexia Lin, Stephanie Smith, Alecia Septer, Christopher Rycroft, Eva Kanso